SPAST Abstracts https://spast.org/techrep <p><strong>SPAST Abstracts </strong>publishes the extended abstracts of the papers presented in the First International Conference on Technologies for Smart Green Connected Society 2021</p> <p><strong>SPAST Abstracts </strong>are open access and provide the audience with the insights into the latest research trends in the field.</p> <p><strong>SPAST Abstracts </strong>is the part of the SPAST Open Access Research series and is google scholar indexed.</p> <p> </p> SPAST Foundation en-US SPAST Abstracts The DIGITAL MODERNIZATION AND NECESSITY OF ELECTROMAGNETIC COMPLIANCE: CONCERN ABOUT HUMAN WELL-BEING IN FUTURE https://spast.org/techrep/article/view/2892 <p>Digital Modernization and Digital transformation have become a predominant source of electromagnetic interference (EMI) in today’s world [1-2]. The DC-to-DC Converters market is also expanding due to the emergence of digital market. DC to DC converters produce a lot of EMI and affect the performance of neighbouring sensitive systems. It is very important to comply with specifications to ensure electromagnetic compatibility (EMC) standards by prioritizing the sustainability and incorporating the social responsibilities for the human well-being. It’s really a great challenge to the design engineers to give a best solution to EMI and at the same time producing a cost effective system. During the development of a new system itself at most care need to be taken to prevent EMI. Numerous design methods, simulation tools&nbsp; are available to predict the noise level and provide feasible/reliable solutions to the problems at low cost. In-spite of that, there are some deviations in the end results in reality compare to the simulated values. This research paper focusses on the&nbsp; quick review of Electro Magnetic Interference, EMC standards as well as the comparative&nbsp; analysis of &nbsp;simulated &nbsp;and experimental EMI measurements of a DC-DC converter.</p> JANAKI G Ramya K Copyright (c) 2021 JANAKI G, Ramya K 2021-10-21 2021-10-21 1 01 Classification of Power Quality Disturbances in Emerging Power System Using Discrete Wavelet Transform and K-Nearest Neighbor https://spast.org/techrep/article/view/550 <p><span style="font-weight: 400;">Power quality becomes a highly important issue in the power system operation due to the increasing use of power electronic devices. Waveform distortions are frequently caused by the power quality disturbances such as sag, swell, interruption, harmonics, flicker, transients, and notch. These disturbances cause malfunctions, instabilities, and failure of end user equipment’s [1].</span></p> <p><span style="font-weight: 400;">It is important to select appropriate features for the classification of PQDs. In order to extract features from the captured signal, signal processing techniques are used. These features are further fed to the classifier. The feature extraction is done in two steps. To begin, the time domain voltage signal is processed using signal processing techniques. Second, extraction of appropriate feature is done using the processed signal. A well selected feature vector reduces the classifiers load [2]. Features can be directly extracted from the original time domain signals, and from the transformed frequency domain signals. To convert the time domain signal into a frequency domain signal, signal processing techniques such as Fourier transform (FT), short-time Fourier transform (STFT), wavelet transform (WT), and S-transform (ST) are utilized.</span></p> <p><span style="font-weight: 400;">The frequency contents in the signal were extracted using FT. The frequency content of the signal can be used to identify some PQDs. However, FT is ineffective for transient signals. This is due to the fact that FT only tells you if a frequency component exists, but not when it appears [2]. In order to get this information, the time-frequency localization techniques are used. This enables you to obtain time-evolved signal components in different frequency ranges. This problem can be solved by using STFT, but it has a fixed window size. The STFT approach is found to be insufficient for evaluating non-stationary signals. Hence there is a requirement of efficient and powerful techniques for analysing non-stationary signals [3-6]. Many researchers have recommended Wavelet transform for the analysis of PQDs to overcome the fixed window width problem of STFT [7]. This approach automatically adapts to give correct time and frequency resolutions. High-frequency signal components have a higher time resolution, whereas the low-frequency signal components have higher frequency resolution with this technique. These characteristics make the WT ideal for analysing power system transients induced by a variety of PQDs.</span></p> <p><span style="font-weight: 400;">In Wavelet transform wavelet is used as the basis function, and it scales according to the frequency under consideration. The WT delivers superior results than the FT and STFT because the basis function is a wavelet rather than an exponential function. The WT divides the signal into several frequency levels and displays them as wavelet coefficients. Continuous wavelet transform (CWT) and discrete wavelet transform (DWT) are used based upon type of signal under study. CWT-based decomposition is used for continuous time signals, while DWT-based decomposition is used for discrete time signals [8].&nbsp;</span></p> <p><span style="font-weight: 400;">This paper proposes a discrete wavelet transform and KNN based approach for the classification of PQDs. The PQDs such as sag, swell and interruption are created by simulating the emerging power system using MATLAB Simulink. These disturbances are further analyse using wavelet transform for feature extraction. The features extracted from DWT are further used for training and testing the KNN classifier.</span></p> Ravishankar Kankale Copyright (c) 2021 Udit Mamodiya 2021-09-15 2021-09-15 1 01 Random Space Vector PWM for Acoustic Noise Cancellations in Voltage Source Inverter PMSM Electrical Vehicle Drive System https://spast.org/techrep/article/view/2818 <p>Pulse Width Modulation (PWM) for Voltage Source Inverters (VSI) has grown in recent years. For any motor drives with low common mode voltage and high DC-link voltage usage, a new age PWM methods have been developed in current era. In PWM inverters the external noise tricky. To suppress those multifrequency noise the chokes/filters have been proposed and connected in the outside of the VSIs. However, these methods suggest higher installation drive cost. Despite the fact that the suppression filters are easily get damage and it has its own age limit. In EV drive applications, this technique uncovers extensive promises. Therefore, the interest of EV manufactures is to find out the solution through inverter PWM itself. The random pulse width modulation (RPWM) is the most promising method amongst all the PWM methods as it has owning characteristics to&nbsp;avoid EMI noises [1]. The&nbsp;RPWM is the ideal PWM for handling induction motor drives because of its simple approach and inexpensive cost, making it one of the most efficient PWM schemes. In other side, space vector PWM(SVPWM) is superior in terms of inverter DC-link voltage utilizations. Likely all recently developed PWMs are having their own advantages and boundaries. Considering the EV drive requirements; they need high DC-link (battery voltage utilization), lesser harmonics and lesser noises. Hence the new interest to hybrid the PWM methods is getting famous these days. The most widely used technique was the random pulse position pulse width modulation, which involved changing the switching events in an operational frequency cycle at random with the modulated carrier frequency [2,3]. If SVPWM is utilised to incorporate RPWM, the alteration is accomplished by the researcher by modifying the slope of the carrier triangle or the angle of the space vector reference [4]. The random signal is employed in RSPWM instead of the carrier triangular wave form modification to provide the switching action. There are PWMs is suggested through spreading multifrequency harmonics. Nevertheless, these methods ignore the impact of acoustic noise and the use of inverter DC-link voltage. The generating the asymmetric carrier wave is important for RPWM and it is digitally implemented without the use of an external circuit [5]. &nbsp;More unique states are required to generate a random bit number, which necessitates a larger number of consecutive digital states. However, as the number of digital circuits grows, therefore does the expense and difficulty of implementation. As a result, the researcher suggested using a linear feedback shift register (LFSR) to increase randomization. The LFSR code generator, also known as a pseudo-PWM code generator, operates by leveraging a binary number's digital logical process.</p> <p>&nbsp;&nbsp;&nbsp; This paper focuses to use RPWM and SVPWM combinedly (called RSVPWM) to generate the PWM to reduce the acoustic noise and more unitization of DC-link voltage. The SVM works using multicarrier (carrier waves with distinct fixed frequencies) that are chosen using a random binary bit generator. The suggested RSVPWM generates pulses with a randomised triangular carrier (10 ± 2.5 kHz), whereas the traditional RPWM approach uses a fixed frequency triangular carrier and a random pulse location. This is work, the random binary is generated using two FPGA-based PRBS bit (8 bit and 16 bit) generators. The SVM was created using the same FPGA controller and uses the PRBS binary selector block to generate random carriers. A three-phase VSI linked 3&nbsp;HP, 250V Battery, EV grade&nbsp;PMSM&nbsp;motor is used to validate the proposed PWM performance.&nbsp;&nbsp;A six switch (Power MOSFET – SCH2080KE) inverter power module (IPM) is used as an inverter drive&nbsp;to evaluate the experimental feasibility of the developed RSVPWM. The simulation and hardware findings reveal that the VSI and motor function similarly to the traditional MCRSVPWM, however the noise power spectra of current, voltage, dominant harmonic components, and acoustic noise spectra are lowered when compared to previously published RPWM approaches.</p> bharatiraja Chokkalingam Ravi Eswar K M Munda JL Copyright (c) 2021 bharatiraja Chokkalingam, Ravi Eswar K M, Munda JL 2021-10-17 2021-10-17 1 01 Modeling for demand response optimization using incentives based on the previous day https://spast.org/techrep/article/view/226 <p>The sustainable developments and energy strategies currently being developed in the world imply policies of innovation and technological optimization. In this way, we will advance towards green intelligence and a smart city [1]. Furthermore, the electric power grid faces significant changes in the supply of resources and the type, scale, and demand patterns of residential users [2]. Usually, the energy industry is based on a centralized grid that is supported by its natural resources and generation plants. Power generation in existing utilities generally exploits non-renewable sources, which negatively impacts the environment [3].&nbsp; Demand response (DR) is a solution to this challenge that has excellent benefits and efficiency. This means that consumers can intelligently manage their use to pay the low cost in peak hours when energy prices are high [4]. DR schedule optimization is the potential to schedule a portion of the electricity demand in smart energy systems. It is a significant opportunity to improve the grid efficiency [5].</p> <p>&nbsp;</p> <p>Power systems currently face different challenges, such as low efficiency, high energy losses, high emissions, and a high possibility of exercising market power [6]. Integrated Demand Response (IDR) optimization methods mainly address the dynamic switching of energy forms (by disconnection, renewable connection, conventional electrical connection, among others) and uncertain variables in the systems caused by the domestic load and unconventional energy [7]. Furthermore, it is estimated that the electricity demand will increase significantly due to population growth, the increasing penetration of green technologies, electric vehicles, and cogeneration systems [8].</p> <p>&nbsp;</p> <p>This article presents simulation scenarios of demand response for incentives based on the "day before." Its main objective is to help power systems during peak demand hours and also during contingencies. This study is essential for the following reasons: (1) A short DR Integration overview is performed on consumers' time-series responses to prices based on the "day before" transaction scheme, (2) provides preferred options for a solution that reflects the uncertainty caused by volatile electricity market prices and demand in the decision-making problem.</p> <p>&nbsp;</p> <p>Through computational experiments (Gamside software), we demonstrate the validity of the data obtained. We achieved active participation based on the “day before” work scheme in DR. 100% coverage of the Demand was achieved for each hour in percentages from 25% to 100% in optimization case studies. The maximum capacities of contribution to the grid were from 2500 to 6000 kW/h. This allowed having inputs for decision-making by introducing the rational response of the consumer and the agents of the energy integrator.</p> <p>&nbsp;</p> <p>The optimization problem is developed in Gamside supported by its solution algorithms that are an optimal development tool. Two case studies were modeled, and the main results are shown in Figures 1 and 2.</p> Favian Moncada Alonso de Jesús Chica Mónica Castaneda Sebastian Zapata Andres Julian Aristizabal Copyright (c) 2021 Favian Moncada, Alonso de Jesús Chica, Mónica Castaneda, Sebastian Zapata, Andres Julian Aristizabal 2021-09-09 2021-09-09 1 01 Dr Bharatiraja https://spast.org/techrep/article/view/2798 <p>The multi-level inverters (MLI) are used in most of the power electronic industries for its better harmonics performance, lower switching stress, lower losses etc. Generally, the 3-phase motors are in practice, but in recent years the multi-phase motors are gaining attraction due to its lower switching stress, reduced current per phase and better harmonic performances. For increasing the AC output voltage, the Z-source converter circuitry uses two identical structures: X-shaped capacitance and inductance, and an impedance network connected between the DC input source and the inverter circuit. The Neutral-Pointed Clamped (NPC) MLI is a topology from the MLI family that can accommodate all of the circuit and operation features of a traditional two-level inverter. The preceding literature review gives an overview of the work that has been done on space vector PWM development and implementation. It, on the other hand, lacks a thorough understanding of Z-source MLI space vector PWM development and implementation. The performance of similar space vector PWM on Z-source NPC-MLI with voltage buck and boost capabilities is examined using an X network for balancing the clamping level to assure voltage waveform quality and harmonics performance. Space vector modulation concepts integrated in Z-source NPC-multilevel inverter would constantly operate with the fewest number of device commutations per half switching carrier cycle and is configured to switch with low harmonic distortion. For phase current balancing, these methods select the inverter's nearest switching (nearest three vectors (NTV)). Although the NPC-MLI has been proven to be superior for drive applications, future PWM strategy tweaks and new topology advancements in the Z-source family can expand its application reach. In NPC MLIs, the SVPWM utilised for neutral point capacitor voltage management, neutral point voltage balancing is a crucial element.</p> <p>&nbsp;&nbsp; This research describes an enhanced space vector PWM for a Z Source Multi-Level Inverter that provides a single–stage power conversion by using single impedance (Z) network to raise its output AC voltage via shoot-through (ST) and non-ST. Nonetheless, the ST states limit the modulation index and create a large ST current in the phase legs of the inverter. The inductive boosting voltage and output levels are directly balanced by the Z networks. Existing approaches use the whole ST, which uses more switching commutations every cycle, resulting in unbalanced inductor charging and discharging, as well as higher harmonics in the output voltage and currents. This paper presents a new development of space vector PWM (SVPWM) model to improve the DC link unitization and DC link capacitors to balance the charging and discharging of inductors in a Z network. Simulations and experiments on a 2kW prototype in an FPGA setting with current schemes validate the suggested method. Its performance was tested using an induction motor.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp; The proposed space vector PWM for a three phase 2kW three-level Z-source NPC multilevel inverter with an adjustable speed induction motor drive is explored for experimental verification. The Xilinx Spartan-6 -XC6SLX9 FPGA controller is used to corroborate the PWM signals.</p> bharatiraja Chokkalingam c Santha Kumar Copyright (c) 2021 bharatiraja Chokkalingam, c Santha Kumar 2021-10-17 2021-10-17 1 01 Design and Development of High Performance 3kW Electric Vehicle Grade Switched Reluctance Motor https://spast.org/techrep/article/view/1523 <p>In modern era the automotive industry transformation to electrifying from internal combustion engine to electric vehicles (EVs). The shortage of fossil-based sources demands increasing the price and high emission of greenhouse gas emission transportation to shift go green. The EVs benefits big diversity in fuel portfolio, reduced dependence on fuel sources, energy independence, healthier environment and for smart cities. The new e-mobility models and emerging technologies helps to improve the EV in the market last two decades. The main challenge in EV is High cost and low mileage, these two key factors are primarily dependence on electric motor(e-motor) [1]. To achieve better EV performance and overcome the problems by improve higher power and torque density, increasing the efficiency are main challenge in advanced e-motor design. Often to attain these goals using non-permanent magnet material, constructing the stator and rotor out of minimum inductance, high permeability and low loss soft magnetic materials. The optimal performance of EV using low-cost material in e-motor design higher acceleration, increasing payload capacity, improving range and improving space savings [3]. At present e-motors are rare earth material permanent magnet synchronous motor has high efficiency and power density is suitable for EV powertrain with high cost. The non-magnet material induction motor has developed control techniques with low cost is suitable for EV powertrain with low efficiency and high core loss.</p> M.Deepak janaki gopalakrishnan Bharatiraja Chokkalingam Copyright (c) 2021 Deepak Mohanraj, janaki gopalakrishnan, Bharatiraja Chokkalingam 2021-10-07 2021-10-07 1 01 Frequency Stabilization of Stand-alone Hybrid Microgrid with tuned PID controller https://spast.org/techrep/article/view/2909 <p>Frequency Deviation is a major concern in a power network due to the frequent load changes. The stand-alone hybrid Microgrid is developed with wind/ and solar systems with MPPT techniques, and this system also faces frequency instability due to the source and load variation.PID controllers are used to mitigate the frequency deviation in the proposed stand-alone hybrid Microgrid. The PID controller parameters are optimized using the Ziegler – Nichols method. The system is developed in Matlab Simulink, and the proposed Ziegler-Nichols tuned PID controllers maintain the system frequency within the IEEE standards under both source and load variations.</p> NISHA G Jamuna K Copyright (c) 2021 NISHA G, jamuna k 2021-10-22 2021-10-22 1 01 REACTIVE POWER INJECTION TO GRID USING TRANSFORMER-LESS MOSFET BASED SINGLE PHASE INVERTER USING PV TO ACHIEVE HIGH EFFICIENCY https://spast.org/techrep/article/view/2625 <p>The objective of this paper is to improve the power quality of the system by injecting power in to the grid using transformer-less MOSFET based single phase inverter using PV to achieve high efficiency.</p> <p>The developed topology for PV inverter is proposed with following objectives:</p> <ul> <li>Designed switching strategy for inverter to reduce the flow of leakage current.</li> <li>Developing a gate pulse switching of Grid-tied Inverter with combination of SPWM and triangular wave.</li> <li>Comparing the results of simulation and hardware of proposed topology.</li> <li>As transformer is considered heavy weighted and expensive the proposed topology is designed to implement an inverter circuit without transformer to obtain maximum efficiency and reduce Total Harmonic Distortion.</li> <li>Injecting reactive power into the system to reduce losses and hence increase the overall efficiency.</li> </ul> <h1>Methodology:</h1> <p>The transformer-less inverter has an increasing demand due to its low cost, high efficiency and reliability. The elimination of transformers from grid connected PV enables to create the leakage currents across stray capacitance, which is connected between PV and ground. To overcome this disadvantageous issue, the topology used is a single step conversion process of directly connecting coupled inductor to the grid. The efficiency and the quality of AC output current is improved by implementation of high frequency PWM switching commutation to the converter. The proposed system is focused to inject reactive power to the grid, changing the controlling techniques used for the Gate Pulse input, and reducing the number of switches, passive elements and harmonics.</p> <h1>Findings:</h1> <p>The prototype for 12V/13.2V is utilized to set up a practical prototype for 200V/310V which can be synchronized with grid-tied PV system. The values for the practical set up are summarized in the above table I. this also aims at producing a maximum efficiency of 98.04% with a THD of 0.915%. The prototype for 12V input, 13.2V output was verified using a hardware and a simulation model. The obtained output AC voltages for both the prototypes are said to be same i.e., 13.2V.</p> <h1>Originality/value:</h1> <p>Our contribution in the emergent field of power generation using renewable resource is designing a prototype of highly efficient transformer-less topology for grid connected PV system. The proposed system topology injects reactive power into the grid and reduces the output harmonics and distortions. Higher switching frequency operation reduces current ripples in the output, while the inverter efficiency is still maintains high. This topology does not face reverse recovery issue even when the reactive power is injected into grid. The CM mode voltage is maintained constant during all switching modes of operation and thus, the leakage current is reduced to a great extent. This topology is a single step conversion process from the coupled inductor directly into the grid without a transformer. The switching commutation of high-frequency pulse width modulation (PWM), increases the converter efficiency and improves and boosts the quality of the output AC current. The efficiency obtained in 12V/13.2V and 200V/310V prototype is observed to be 98.04%<em>.</em></p> M. Vinil G. Ramya M. Moovendan J. Ajay Daniel Mayakannan Selvaraju Copyright (c) 2021 M. Vinil, G. Ramya, M. Moovendan, J. Ajay Daniel, Mayakannan Selvaraju 2021-10-17 2021-10-17 1 01 Exploration of Anomalous Tracing of Records in Smart Home Energy Consumption Dataset https://spast.org/techrep/article/view/2756 <p>Currently, the entire world is in the era of smart grids. The evolution of smart grids is fast by transforming the traditional grids into smarter ones. This transformation is not only limited to macro-level (grids), but also to micro-level (such as cities, buildings, and homes). In recent years, electricity consumers are looking towards renovating their regular homes into smart homes. These smart homes are equipped with advanced metering infrastructure, different kinds of sensors, control units, etc. The smart meter is one of the key components of this advanced metering infrastructure that records the energy consumption data continuously at a predefined rate. All these traces are stored in a file in a format that is specified by the respective utility company, which is used for further computations and analysis. So, the accuracy of the traces plays a major role. But, sometimes, this tracing of data is anomalous due to the malfunctioning of the metering infrastructure, congestion in the network, etc. In general, the respective traces are expected to be gathered and stored under a file representing a day. Any deviation in this is considered as anomalous tracing. This anomalous tracing of the energy consumption data affects the integrity of billing and analytics in terms of demand-side management, real-time load profiles, decision making, etc. Hence, it is required to identify such improper tracing in the energy consumption data. In this regard, this paper proposes a simple approach to identify the anomalous tracing of energy consumption readings. To accomplish this, the file name and the content of that file are considered and compared their timestamps in dates. A continuous automatic search has been performed to verify whether all the energy consumption readings are recorded under the respective date. The proposed approach successfully identified the irregularity in tracing the energy consumption readings. A real case energy consumption dataset ‘Tracebase’ is used for implementing the proposed approach.</p> Pavan Kumar Y. V. Purna Prakash K. Copyright (c) 2021 Pavan Kumar Y. V., Purna Prakash K. 2021-10-21 2021-10-21 1 01 A Stand Alone Building Integrated PV Tied Bidirectional Capability Direct DC Electric Vehicle Charging System through Z-Source Inverter Impedance Network Capacitors https://spast.org/techrep/article/view/2831 <p>Due to declining fossil fuel resources and rising gasoline prices, Electric Vehicles (EVs) have recently regained popularity. Meanwhile, due to the expensive initial cost of the battery, range anxiety or limited travel distance, a lack of charging infrastructure, and poor recharging rates, widespread adoption of EVs is not occurring at a rapid pace. There is a lot of attention in the building-integrated PV (BIPV) for the past few years around the world and they have been designed and integrated in different ways to meet out the building load requirements. The PV design experts and architectural consultants are exploring ingenious techniques, and they have delivered the innovative building elevation design with wall mounted PV structure. Even though these BIPVs are supplying the local building loads, due to the increase in the electrical vehicles (EVs) users in the commercial buildings, there is need to provide sufficient power requirement for their fast charging.&nbsp; Due to the consideration of EVs with respect to the environmental sustainability, high progression is expected in the near future, and it will because extreme surges in the claim while charging them during rush hours (particularly during daytime). Hence similar to rooftop PV system, BIPV is a trustful system to provide the electricity to the EVs.&nbsp; Nevertheless, numerous challenges are still addressed in the fast charging with PV and utility grid power. Hence, the proposal motivates to design high-efficient and low-cost wall mounted BIPV integrated electric vehicle DC fast charging system to meet out the EV power requirement for their quick charging [1,2].</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; A single stage inverter called Z-source inverter (ZsI) can buck or boost as well as reverse the input dc voltage. In PV-grid-connected/ Stand Alone applications, it has sparked a lot of attention in current era. The ZsI able to boosts the input dc voltage to match the inverter-side ac output voltage requirements with impedance network two capacitors and two inductors. The passive components are crucial to the operation of a ZsI [3]. It opens up the possibility of incorporating energy storage devices into such a system. The capacitor voltage of impedance network of the ZsI can be tapped and from there DC supply can be taken. Hence in this papers a modified ZsI with split capacitors to provide the DC supply to the EV charging side pulsating transformer. The conventional X- network type ZsI C<sub>1</sub> and C<sub>2 </sub>capacitors are splitted into two namely C<sub>1</sub> as C<sub>11</sub> and C<sub>11 </sub>besides C<sub>2</sub> as C<sub>21</sub> and C<sub>22</sub>. This capacitors are connected with the primary widening of the isolated full-bridge converter (IFBC). Hence the isolated full-bridge converter receive the two cycle pulsating DC from the both primary winding of IFBC. The secondary side of the IFBC connected with EV Battery. This topology also proves a bidirectional capability to get the power from the battery and charges the impedance network capacitors. &nbsp;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp; The simulation and experimentation is conducted for the proposed BIPV EV charging ZsI standalone system. The Test set is built for established values of 1.2-kWp roof-top PV panels (15 tin film panels, each 90W) attached single-phase ZsI standalone system. The 24V/20Ah li-iron battery is used for the EV battery</p> <p>The proposed method is capable of any EV charging architecture anfd it can be used in a centralised charging setup in semi-commercial venues such as a supermarket car park. This approach can be extended to wall and rooftop PV&nbsp;inverters for grid connected and domestic applications. This research presented an energy storage topology based on the symmetrical operation of a Z-source converter's impedance network</p> bharatiraja Chokkalingam gsilangonitt@gmail.com G.Ramanathan Copyright (c) 2021 bharatiraja Chokkalingam, gsilangonitt@gmail.com , G.Ramanathan 2021-10-17 2021-10-17 1 01 Performance Analysis of Standalone Photovoltaic System using PVSYST https://spast.org/techrep/article/view/1696 <p>Electricity has become one of the essential needs of today’s life like food and shelter. The entire technology and advancements are completely dependent on the power which should not be interrupted at any cost. The entire world is completely damaged and polluted to the core due to the smoke, Radiations, etc., These damages create various environmental and Health issues out of which many of the problems cannot be addressed at all. So, we are in an urgent need of creating pollution free energy for an environmental-friendly scenario. Because of these requirements, many renewable energies have come into Utilization.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Renewable Energy are the inexhaustible energy given by the nature. The different renewable energies are Solar, Wind, Hydroelectric, Ocean, Geothermal, Biomass and Hydrogen. Solar and wind energy have been leading energy producers compared to all others. Wind Energy production involves a very high Installation cost as compared to Solar Energy. So solar energy production has become more common. In India, the development of solar energy production has been rapid in the last few years. The country has total installation capacity of 44.3MW as on 31<sup>st</sup> August 2021 with an investment of US $100 Billion. India has been ranked as five among the countries in solar energy production all over the world. Karnataka, Telangana, Rajasthan, Andhra Pradesh and Gujarat are the states which have more production of photovoltaic energy.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Out of many Renewable Energy Sources, Solar Energy Production has become very competitive. The different types of Photovoltaic System mainly include Grid Connected System, Standalone system and the Hybrid system. Many software like PVsyst, PVSOL, HOMER Pro, SOLARGIS, System Advisor Model (SAM), Solar Pro have emerged in the recent days which enables us for designing a Photo voltaic system, Energy Production, Energy Consumption, Energy Utilizations, Analysis of Cost, etc., for any specific application. The above said analysis can be made on Hourly basis, Monthly Basis, Component-wise, etc., This work focuses on simulation of Stand-alone Photovoltaic System with PVsyst Software (PVsyst 7.2) on a small geographical location at Madipakkam, Chennai in Tamil Nādu, India. PVSyst is a software which assists us in designing and analyzing various Photovoltaic systems like Grid connected, Stand Alone and pumping applications. The project can be simulated with detailed hourly consumption and economic valuation. Meteo Databases and Component Databases listed by the manufacturers can also be utilized.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; This paper analysis on 100Wp Standalone Si-Poly Photovoltaic System. The simulated system consists of 72 cells, 7 strings of 1 module each. The entire data sets of radiation and temperature has been taken from Metronome 8.0. The energy consumption has been considered for 89.9KWh/month. The Battery used is Lead Acid with 80% DOD and battery voltage of 24V. The Performance Ratio and the Normalized Productions for different months of the year has been studied. The different losses linked with the Stand-alone plant has been studied and the feasibility of the System has been Predicted for different parameters. The detailed component wise loss diagram has also been given by reducing which the efficiency of the entire system can be increased.</p> BHUVANESWARI D.Susitra W.Abitha Memala Copyright (c) 2021 BHUVANESWARI, D.Susitra, W.Abitha Memala 2021-10-08 2021-10-08 1 01 Drone Operated Bidirectional Wireless Charging System for Energy Constrained Devices in Smart Farming Applications https://spast.org/techrep/article/view/1498 <p>The new age of technology has revolutionized the way the agriculture sector functions. Smart machines are gradually captivating primitive farming techniques and aid in increasing the quality and yield of crops. The implementation of Energy Constrained Devices (ECDs) into the agricultural sector has grabbed the curiosity of many researchers and has opened up opportunities for autonomous monitoring of soil-crops health. This research benefits the agricultural sector in providing top quality yield at minimal human resources and uses smart machinery, such as drones to monitor the progress on the field. This research aids in<br>implementing the use of ECDs for collecting field data such as moisture content, temperature, mineral requirements, etc. at a given area. The devices are sealed with wireless charging circuits in them. The drones are used to wirelessly charge these ECDs at a predicted interval of time.</p> Prithvi Krishna Chittoor Copyright (c) 2021 Prithvi Krishna Chittoor 2021-10-07 2021-10-07 1 01 Performance Analysis of Five Phase NPC MLI with Phase Shifting Carrier Pulse Width Modulation https://spast.org/techrep/article/view/2658 <p>The multi-level inverters (MLI) are used in most of the power electronic industries for its better harmonics performance, lower switching stress, lower losses etc. Generally, the 3-phase motors are in practice, but in recent years the multi-phase motors are gaining attraction due to its lower switching stress, reduced current per phase and better harmonic performances. The 5-phase motors are preferred among multi-phase motors for its better reliability and robust control [1]. The 5-phase Neutral Point Clamped Multi Leve Inverter (NPC MLI) are used for driving the 5-phase motors [2]. The controlling of MLI is done by multi-carrier Pulse Width Modulation (PWM) techniques which is categorised as Level Shifting Carrier PWM and Phase Shifting Carrier (PSC) PWM [3]. The Level Shifting PWM is classified as Phase Disposition (PD) PWM, Phase Opposition Disposition (POD) PWM and Alternate Phase Opposition Disposition (APOD) PWM. The amplitude and frequency of carrier signal are same for all the above mentioned PWM techniques. The position of carrier signal is displaced in PD PWM, while the phase angle of carrier signal below the zero reference is shifted by 180<sup>o</sup> in POD PWM techniques and the phase angle of alternate carrier signals are shifted by 180<sup>o</sup> in APOD PWM techniques [4]. In PSC PWM techniques, the phase angles of each carrier signal are shifted by particular degrees while the amplitude, frequency and position are same for all carrier signal [5]. This angle shift of each carrier signal is selected based on the number of levels in inverter.</p> Vinoth Jayakumar Bharatiraja Chokkalingam Santhakumar C Munda Josiah Lange Copyright (c) 2021 Vinoth Jayakumar, Bharatiraja Chokkalingam, Santhakumar C, Munda Josiah Lange 2021-10-19 2021-10-19 1 01 Integrated Double-sided LCC Compensation Topology for an Electric Vehicle Wireless Charging System https://spast.org/techrep/article/view/2825 <p>&nbsp; Due to declining fossil fuel resources and rising gasoline prices, Electric Vehicles (EVs) have recently regained popularity. Meanwhile, due to the expensive initial cost of the battery, range anxiety or limited travel distance, a lack of charging infrastructure, and poor recharging rates, widespread adoption of EVs is not occurring at a rapid pace. The aforementioned concerns can be addressed with wireless power transfer (WPT) systems that use dynamic power transfer while the EVs are moving. It has the potential to lower the depth of depletion of the on-board battery, extending the battery's life cycle. Furthermore, a smaller battery not only decreases vehicle weight but also lowers vehicle costs due to improved performance. The WPT charging pads are used at regular intervals on frequently used routes; the range constraint is effectively alleviated or erased. Similarly, power transfer to EVs can be used directly to propel, avoiding losses of about 15% caused by energy stored in the battery. It is acknowledged that infrastructure investment costs may be expensive at first, but RWPT systems are best implemented in heavily frequented highways, in which case just a small portion of the entire roadway is required to execute. Furthermore, electricity charging costs can be collected from EVs that use power segments similar to toll booths to help support infrastructure costs. WPT has been studied and successfully applied to applications such as material handling and biomedicine in the past. Because of the adverse environment and particular properties of the roadway, adapting this technology to EV applications is currently a challenge. The key problem is higher power transfer rates (50-100 kW for SUVs, 8-20 kW for automobiles), charging distance, magnetic field leakage, high power transfer efficiency, high pressure and vibration in heavy traffic, compatibility, and extended expected life.</p> <p>The majority of WPT EV charging experiments to date have concentrated on static systems, with only a few inquiries into roadway (dynamic) charging of EVs. Furthermore, the WPT technology for static charging has not been optimised to provide high power transfer efficiency. The selection of power electronic circuit topologies, magnetic coupler design, and compensator selection are all important factors in the efficient design of static or dynamic WPT charging systems. An inductive-based wireless charging system is nothing without coils. They are responsible for determining the power transmission capability and efficiency. The geometry of the coils is an important property since it is linked to the coupling-factor (K) of the coil construction and the Quality-factor (Q) of both primary and secondary coils. The compensator topology design is is another key feature of a WPT&nbsp;since it enhances transmission of power, reduces the power source's VA rating, and aids in soft switching devices. The researchers add a coplanar coil to the primary coil pad&nbsp;in order to increase coupling and efficiency using the Series-Series (SS) compensator architecture.. The compensation circuitry is divided into four types: PP, PS, SP, and SS, with the letters "P" and "S" denoting the way the resonant capacitor is linked to the coil, with "P" denoting parallel and "S" denoting series.</p> <p>Double-sided LCC (DSLLC) compensation topology that is more favourable to improve&nbsp; &nbsp;the K, Q and load condition handling.&nbsp; The resonance frequency is not only independent, although it is very efficient and provides wide misalignment power transfer.&nbsp;&nbsp; However, the DSLLC topology has a huge volume. This work offers a new integration approach for a wireless charging system employing DSLLC compensation structure in order to optimize modeling and development while maintaining the benefits of compact and high efficient. The proposed DSLCC WPT design is provide a wide variation of Magnitude of magnetic intensity and reaches to 93.2 % efficiency when the misalignment is close zero. &nbsp;The lab scale experimentation is also conducted to validate the simulation results.&nbsp;</p> bharatiraja Chokkalingam Aganti Mahesh aganti mahesh Copyright (c) 2021 bharatiraja Chokkalingam, Aganti Mahesh, aganti mahesh 2021-10-17 2021-10-17 1 01 Fault Analysis for Devising Protection Scheme in Microgrid https://spast.org/techrep/article/view/3389 <p>A microgrid is an active distribution network which can be operated in grid connected as well<br>as in islanded mode. It is a cluster of distributed generators. The objectives of the microgrid<br>are : Remote electrification and Local generation of power , Reliable supply of power and<br>Clean sustainable energy.<br>Following are the main challenges in microgrid:<br>• Protection of microgrid: Insufficient level of short circuit current<br>• Control &amp; Protection of microgrid is one of the major challenges<br>• On occurrence of any permanent fault, protection system or devices should quickly isolate<br>the microgrid from main grid to protect the microgrid<br>• Fault current levels vary as there are distributed generation units connected to grid and in<br>turn affects the performance of the relays connected in the system<br>•The reverse or backward power flow is also one of the main challenges for microgrid<br>operation.<br>•Insufficient level of short circuit current and Intermittence in the generation<br>•Topological changes due to connections/ Disconnections of DG’s.<br>Protection of a microgrid is a major challenge in the development of a renewable energy based<br>microgrid project There are various types of protection devices which can be employed for the<br>protection of microgrid.<br>Regular overcurrent relays cannot be employed for the protection of microgrid when<br>changeover from one mode to the other mode takes place. The reason behind this is the<br>difference in short circuit current in both the mode, this will affect the performance of the relay<br>in terms of time of operation and relay may fail to operate. Therefore, Coordination and setting<br>of the relays need to be updated on regular intervals. Most of the DG’s are renewable in nature<br>and are grid integrated via power electronic devices in between. Also, there are storage<br>devices integrated to the system to enhance reliability as renewable energy sources are<br>intermittent sources. The low voltage dc microgrid is basically employed to integrate<br>Distributed generators and sensitive loads especially electronic loads [1]<br>Fault Analysis for Devising Protection<br>Scheme in Microgrid <br>SPAST Abstracts Sangeeta Modi , Dr. P Usha , IGCSTS-1, 2021<br>The integration of various DG’s, storage devices and loads via power electronic interfaces in<br>between makes them to respond to the fault current in different way. Fault current may change<br>according to the selected device. So, coordination of these devices is very much required. For<br>this purpose, It is required to analyse the system behaviour properly against various types of<br>faults.<br>Load flow analysis can be carried out for this purpose Microgrid configuration plays very<br>important role in deciding the settings of the protective devices. Depending upon the<br>configuration selected fault current may vary in the various devices integrated in the system.<br>[2-3] One of the important requirements in microgrid protection is very fast real time<br>communication channel in between the protective devices and the master controller unit to<br>ensure security and reliability. Detection and location of fault can be found out with the help of<br>these communication channels based on most sensible standards such as IEC 61850[3-4].<br>As compared to traditional ac distribution systems, protection part has been challenging for a<br>dc system. [5] Grounding system is well explained and differential protection algorithm has<br>been applied. [6] For fault location identification the traveling waves concept is applied which<br>is caused by a fault. This approach has been tailored for ac fault protection as well [7] The<br>comparison between two arrival times along with the wave propagation velocity can identify<br>the fault location<br>In [8] The best part of the developed adaptive protection scheme is that it monitors the<br>microgrid continuously and updates relay fault current immediately according to the conditions<br>in the system but this scheme is not capable of finding the shortest path of isolation.[9].<br>In [10] The central controller presented involves the multiple features for proper coordination<br>of distributed energy resources to serve the critical and non-critical loads. Initiation of<br>protection techniques at the time of fault occurrence at the grid end or in microgrid ensures<br>stability and reliability in the system.<br>It is always advisable to divide the complete microgrid network into number of zones . Point of<br>common coupling (PCC) zone could be the main zone where high-speed CBs with suitable<br>relays are required. Another zone could be the feeder protection zone where miniature CB’s<br>with suitable relays can be connected. Third zone could be the service zone near customer<br>where suitable CBs can be employed with appropriate devices for the detection of the fault.<br>Fourth zone could be the zone in which DGs are connected. Fifth zone could be the zone<br>carrying power electronic interfaces. It is very important to know the operational curves of the<br>protective devices during islanded and grid connected mode before connecting them in the<br>system .<br>SPAST Abstracts Sangeeta Modi , Dr. P Usha , IGCSTS-1, 2021<br>Figure 1 Block diagram of the Microgrid System under consideration<br>Figure 2 block diagram with Fault location on AC and DC side<br>In this work multiple renewable energy sources PV sources will be considered along with<br>Utility Grid. DC bus can be maintained at 480V and AC bus can be maintained at 400V, 50Hz<br>according to the load requirement . AC and DC loads will be supplied from AC and DC bus<br>points respectively. AC and DC sides are linked together with Bi-directional Converters<br>Desirable features of a protection scheme employed for Microgrid<br>• Faster operation during high voltage dips (by using high speed standard-based<br>communication IEC-61850)<br>• Adaption capability<br>SPAST Abstracts Sangeeta Modi , Dr. P Usha , IGCSTS-1, 2021<br>• Discrimination: unrequired operation of protective devices should be avoided<br>• Reliability<br>Fault analysis is a pre-requisite for designing protection scheme for any microgrid. In this work<br>fault analysis on a Photo Voltaic ( PV) based microgrid topology will be carried out for<br>deciding the suitable protection scheme. With the help of these results , setting of the<br>protection devices can be decided in future. An adaptive protection scheme using<br>microcontrollers can be realized for the microgrid under consideration as a continuation of the<br>work.</p> Sangeeta Modi Dr. P Usha Copyright (c) 2021 Sangeeta Modi, Dr. P Usha 2021-11-10 2021-11-10 1 01 ENERGY IMPROVEMENT IN DISTRIBUTION NETWORK USING SLIDING MODE CONTROLLER BASED SVC SYSTEM https://spast.org/techrep/article/view/2635 <h1>Abstract</h1> <p>Purpose: This paper presents the power quality improvement using SVC in 14 bus system using Proposed Resonance and Sliding Mode (SM) Controller to improve the power quality. &nbsp;</p> <h1>Methodology:</h1> <p>Static Var Compensator is a shunt type reactive power compensation device used to enhance the energy in the distribution system. Minimized power losses, improved power transfer capacity to stabilize the weak system are the main functions of the SVC system. The instantaneous response of SVC is the main important advantage in comparison with mechanically switched compensation devices. SVC is installed at the point of common coupling to improve the reactive power.</p> <h1>Findings:</h1> <p>SVC is a shunt type reactive power controller to inject reactive power to the grid for the purpose of maintaining required power transmitted from the sender side. Static VAR Compensator is a shunt associated system in parallel with line and It comprises of a TSR or TCR, TSC and filter to inject reactive power to the system. It additionally comprises of different channels for power factor improvement. SVC injects the reactive power to the distribution system using slideing mode controller. The sliding mode controller based SVC system is employed between the source and the load to improve the power quality of the system.</p> <h1>Originality/value:</h1> <p>The performance of proposed resonance and sliding mode controlled 14 bus SVC system are designed and simulated using MATLAB Simulink. The time domain parameters of closed loop controllers are compared and sliding mode controlled 14 bus SVC system has better peak time and settling time of 0.35 sec and 0.34 sec respectively. The percentage of SMC controlled SVC has less steady state error of 2.3 % in comparison with proposed resonance of 2.6%. The real and reactive power of SMC controlled 14 bus SVC system has better performance to PR controlled SVC system. Fuzzy Logic Controller can be employed further in future to analyze the performance of SVC in multibus system. PR controller controlled 14 bus SVC system circuit diagram is depicted in Figure 8. The combination of resonant term and proportional term forms the proposed resonance controller to eliminate steady state error with high gain around resonant frequency. Figure 9 shows the Voltage at bus 3 of closed loop 14 bus SVC system with PR controller and Figure 10 depicts the RMS voltage at bus-3 of closed loop 14-bus SVC with PR controller.</p> <p>The combination of resonant term and proportional term forms the proposed resonance controller to eliminate steady state error with high gain around resonant frequency. The real &amp; reactive Power at bus-3 of closed loop 14-bus SVC with PR controller and its values are 4200 MW and 13000&nbsp; MVAR respectively.</p> G. Ramya M. Vinil J. Ajay Daniel M. Moovendan Mayakannan Selvaraju Copyright (c) 2021 G. Ramya, M. Vinil, J. Ajay Daniel, M. Moovendan, Mayakannan Selvaraju 2021-10-17 2021-10-17 1 01 Passive Filter Topologies for Grid Connected and Standalone PV Systems: A Survey https://spast.org/techrep/article/view/1436 <p>Distributed generation using sustainable energy sources like solar and wind energy has received greater attention to meet increasing energy demand and environmental constraints. Voltage source inverters are a key component in most of the grid connected and standalone distributed generation systems. A passive filter is necessary between the inverter and the grid or the load in these systems to reduce harmonics on the inverter output voltage/current waveforms. Passive filters are simple, inexpensive and involve no complexity [1-2]. &nbsp;</p> <p>First order passive L type filters were used with inverters for attenuation of switching harmonics. As L filters are first order filters, they carry restrictions due to their inevitable large size. LC or LCL&nbsp;&nbsp; filter provides better harmonic attenuation with a reduced filter volume. However, the main disadvantage with LC and LCL filters is the presence of a resonance frequency that can amplify harmonic components that could cause system instability. To alleviate the challenges faced with LC and LCL filters, many higher order filters have been introduced for better harmonic suppression in PWM inverters [2]. Some of the higher order filters include modified LCL topologies, containing either series or parallel LC circuits, tuned at the switching frequency and its multiples, to either bypass or block harmonics. Mutlituned trap filters provide higher harmonic attenuation. An inductor is inserted in the capacitor branch loop of the LCL filter, thus creating a series resonant circuit at the switching frequency creating LLCL filter. The grid side inductor design of the LLCL filter is based on harmonics at double the switching frequency, which enables to decrease total inductance value and size, when compared with LCL filters.&nbsp; However, the filter size increases with more than three traps. Additional series resonant circuit restructures the filter frequency characteristics and the attenuation capability falls off to -20 dB/decade at high frequencies. To overcome the disadvantages of the above filters and provide flexible filter design, a modified LCL filter, named, LTCL filter is proposed where multiple series LC traps are inserted in parallel with the capacitor branch of the LCL filter tuned at the switching frequency and its multiples to form multiple series resonant circuits, helps in providing good attenuation of harmonics around the multiples of inverter switching frequency. As the number of traps increase, it becomes difficult to design individual filter parameters.&nbsp; To reduce circuit complexity, several other higher order filters based on above configurations such as LCL-LC filter, L(LCL)<sub>2</sub> filter, SPRLCL filter, LT-C-L filter, LCPSL filter and (LCR) <sub>trap</sub>-LC-RC filters [2] have been studied and carry their own merits and demerits. Another major shortcoming with these passive filters is that they trigger a resonance between the inverter and the grid causing instability in the system which needs to be damped. Passive damping mechanism is simple with lesser control complexity and involves low cost [1]. Table 1 shows the features of some of the existing passive damping strategies. Various other strategies include RLC Damping, Split Capacitor RL damping etc. [1] which have their own highlight and possess certain demerits.</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p><strong>Table 1. Damping Methods</strong></p> <table width="593"> <tbody> <tr> <td width="311"> <p><strong>Highlights</strong></p> </td> <td width="282"> <p><strong>Challenges</strong></p> </td> </tr> <tr> <td width="311"> <p><strong>Series Resistance Damping: </strong>connecting a resistor in series with the filter capacitor of the LCL filter, simple and adequate damping can be achieved.</p> </td> <td width="282"> <p>With larger resistance values, power losses increase and harmonic attenuation gets affected.</p> </td> </tr> <tr> <td width="311"> <p><strong>Parallel Resistance Damping</strong>: Resistor is placed either across the inverter side inductor or across the grid side inductor or across the filter capacitor.</p> </td> <td width="282"> <p>Increased losses, Placing the damping resistor across the grid side inductor is a good option, however, it becomes challenging to design the damping circuit.</p> </td> </tr> <tr> <td width="311"> <p><strong>Resistance-Inductance Damping: </strong>Placing a parallel RL circuit in series with the filter capacitor.</p> </td> <td width="282"> <p>At power frequencies, the inductor offers low impedance path, thereby lowering current through the resistor hence reducing losses. However at high frequencies, the resistor current dominates and hence the attenuation gets affected.</p> </td> </tr> <tr> <td width="311"> <p><strong>Parallel Resistance-Capacitance Damping: </strong>An additional series RC circuit is connected across the LCL filter capacitor. the high frequency attenuation is retained as 60 dB/decade.</p> </td> <td width="282"> <p>The value of damping resistance used is higher than that with simple resistance damping method; losses also increase with large capacitance ratio and with increased damping branch capacitance, the attenuation gets decreased.</p> </td> </tr> </tbody> </table> <p><strong>Discussion and Conclusion</strong></p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Thus, passive filters carry several challenges and require a suitable structure to realize an efficient PV generation system. The choice of an appropriate passive filter is governed by some of the below mentioned desirable features a) strong attenuation capability at the switching frequency b) robustness against parameter variations c) reduced total harmonic distortion (THD) on the output waveforms d) flexible design to suit different power levels and switching frequencies e) easy implementation f) reduced power dissipation and g) reduced size and cost and g) damping methodology applied. Poor design methods of passive filters lead to reduced attenuation at the switching frequency, larger filter size, higher resonant peaking, distorted output waveforms and higher power losses across the damping elements. Lot of research is being done towards new filter structures and filter design methodologies for voltage source inverters that can address the above mentioned issues. As existing passive filter configurations presented in literature carry one or more of the above mentioned challenges, a research void exists. Thus research work can be carried out to realize and fill the research gap which is to address these challenges and gaps by developing and implementing novel passive filter configurations for voltage source inverters.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; This work attempts to perform a survey of passive filter topologies used in standalone and grid connected systems. Based on the basic filter topologies, many new filtering solutions and structures have been proposed in the literature and this paper reviews some of them. The work highlights new filter topologies that have been developed concentrating on reduced number of elements, reduced size, less cost and lower complexity. A comprehensive survey of damping strategies that are used with the passive filters to suppress resonance is also carried out. This paper would serve as a base for selecting a particular passive filter topology for standalone and grid connected applications.</p> Meenakshi Jayaraman Sreedevi V T Copyright (c) 2021 Meenakshi Jayaraman, Sreedevi V T 2021-09-30 2021-09-30 1 01 A Comprehensive Review of Microgrid Challenges and Protection Schemes https://spast.org/techrep/article/view/2611 <p>For the greater part of a century, the world has been mobilizing towards more sustainable methods of energy production. This has led to an increased dependence on renewable energy resources to meet a snowballing demand for reliable and consistent energy to feed a rapidly growing population. This trend can be accredited towards a common vision of sustainable development. Additionally, reserves of conventional sources are rapidly depleting, with a foreboding environmental crisis brought by the profligate consumption of energy resources like coal and oil. Moreover, the problems associated with traditional electric utility grids are several, such as the archaic architecture and the absence of last mile connectivity. The conservative electric grid also inhibits sustainable development due to its rigidity and obstinacy.</p> <p>Distributed generation through renewable energy resources and microgrids have repeatedly proved as sustainable alternatives to mitigate the portending crises. Microgrids provide a versatile topology with the option of dispersed generation and provision for future expansion. This is further backed by the impressive growth of microgrid markets over the last few years. However, the existence of a non-conventional landscape of microgrids and the inherent intermittency of renewable energy resources can cause unique challenges. The control and protection strategies used for the conventional utility grid have proven unsuitable for microgrids. The microgrid protection challenge has established itself to be a conundrum due to the bidirectional flow of power, blinding of protection, and the dynamics of fault current. This paper attempts to be a comprehensive review of microgrid challenges and existing protection schemes.</p> <p>The contents of this paper can be realized in four segments. The first segment presents the technical definition of a microgrid and proceeds to present an overview of the microgrid market scenario. The following segment discusses the classification of microgrids, and the control strategies used. The paper then proceeds to elaborate on various challenges associated with microgrids, including voltage and frequency issues, resynchronization issues, power quality and inertia issues, cybersecurity risks and protection challenges. Subsequently, various protection schemes used for microgrids are discussed. More recent schemes such as Wide Area Protection and Artificial Intelligence algorithms are also presented in this paper. The last segment of the paper gives an overview of relay coordination and various optimization algorithms used to achieve the same. The paper concludes with a brief overview of a few IEEE and IEC microgrid standards and codes.</p> Nirupama Srinivas Sangeeta Modi Copyright (c) 2021 Nirupama Srinivas, Sangeeta Modi 2021-10-17 2021-10-17 1 01 Radial Basis Function Artificial Neural Network Optimized Stability Analysis in Modified Mathematical Modeled Type-III Wind Turbine System using Bode Plot and Nyquist Plot https://spast.org/techrep/article/view/3387 <p>Stability is the major factor that should be maintained in every power system. To predict and to optimize the nonlinear parameters this research provides a control system transient analysis using Bode Plot and Nyquist Plot to regulate the stability in wind power generation. The rotor speed should be balanced with respect to the generation of generator power for viable wind power generation. This study introduces a sliding mode controller for controlling wind speed and preserving system stability, and it may be improved using an Artificial Neural Network based Radial Basis Function Neural Network to eliminate nonlinearities induced by changing wind speed. The tip speed ratio approach is utilized in this study to harvest the most power from wind energy. To optimize this TSR method, a PI-RBFN tuned sliding mode controller was utilized to get maximum power while minimizing active power losses. This proposed approach may be used to address nonlinearities in the pitch angle caused by changing wind speed. As a result, the resilience of the redesigned Type-III wind turbine system is investigated using MATLAB simulink in this study. The simulation results are compared to the current DFIG-based modified Type-III wind turbine method.</p> Bibhu Prasad Ganthia Subrat Kumar Barik Byamakesh Nayak Copyright (c) 2021 Bibhu Prasad Ganthia, Subrat Kumar Barik, Byamakesh Nayak 2021-11-09 2021-11-09 1 01 OPTIMAL LOCATION AND SIZING OF REACTIVE POWER COMPENSATION DEVICES FOR VOLTAGE STABILITY IMPROVEMENT OF RADIAL POWER SYSTEMS https://spast.org/techrep/article/view/1283 <p>With the advancement in technology, the electricity demand is increasing day-by-day. Power supply utilities are facing the problem to expand their network owing to the problems like availability of land in urban areas and Right of Way (ROW). Due to these problems, many of the existing lines are operating nearer to their thermal stability limit. Maintaining the voltage within the limits will be a challenging task for the utilities. Increased loading of the lines is moving the power system to the verge of voltage stability. Many indices are proposed in the literature for predicting the voltage stability of the system. In this paper, L-Index is used for voltage stability analysis of the radial distribution system. L-Index sensitivity method is used to the locate and size the reactive power compensation devices. The effectiveness of L-Index sensitivity method on the larger power system like IEEE-33 bus system is studied. Simulation is done using MATLAB.</p> Bhargavi RN Copyright (c) 2021 Bhargavi RN 2021-10-15 2021-10-15 1 01 Prediction error identification for a closed-loop system with errors-in-variables https://spast.org/techrep/article/view/248 <p>To study whether the predictive error method can also obtain satisfactory results in the closed-loop system with variable errors, the closed-loop situation is deduced by imitating the predictive error method in the open-loop system. The results show that the prediction error method can be used to identify the classical closed-loop system. When the input and output noise are all white noise with mean 0 and Variance 1, the closed-loop system with errors-in-variables can be used to identify the prediction error.</p> <p>&nbsp;</p> <p>&nbsp;</p> Zhang Yun Feng Copyright (c) 2021 Zhang Yun Feng 2021-09-10 2021-09-10 1 01 ENHANCEMENT OF SOLAR PANEL EFFICIENCY USING NEW LIGHT REFLECTION TECHNIQUE https://spast.org/techrep/article/view/2515 <p>In recent years electrical power demand is increased rapidly in fast growing countries like India as electricity is the key source for modern economics. Recent inventions in technology emphasize to concentrate on socio economical power generation to all electrical researchers. Renewable energy sources [1-5] are the non-vulnerable energy sources supports for socio economical power generation. Of course, renewable energy sources are also facing major limitation of its long run availability in environment. This dictates that, vast research is needed for alternative design modifications to overcome the long run availability of renewable energy source. Solar electricity generation is the vivid socio economical power generation and facing with staid limitation of its availability in nature. Various techniques are introduced elsewhere in the world to achieve maximum power from the solar panel within the limited time period only and those techniques inoperative to continuous solar power. Hence, alternative design techniques are needed to overcome these limitations scrupulously. &nbsp;Designing of the solar panels with enhanced panel efficiency compared to the existing solar panels pays more attention in recent years. Few techniques are developed and used to obtain the maximum solar panel efficiency by extracting the maximum power from the solar panels [6-10]. All these existing techniques are constrained due sporadic sun energy in the environment. Hence, the comprehensive research work is needed to be acquainted with suitable technique to achieve the enhanced solar panel efficiency.</p> <p>In recent years, it is observed that, few researchers are initiated to use the concept of light reflection technique [11-14] on solar panels to generate the solar electricity shown in figures 1. In view of this, reflection of light concept is the primeval technique used in many applications adopted here to corroborate the solar panel efficiency. Also, the authors are attempted instantaneous light reflection technique on solar panel to verify the solar panel efficiency compared to existing light reflection concept.&nbsp; Instantaneous lights contain the enormous energy which may affects the strength of the molecules in a semiconductor material. The solar PV cells are semiconducting materials only, so the instantaneous lights affect the strength of the molecules. This results in week bonding between the PV cell molecules and causes the generation of free electrons which in turns into flow of higher amount current in solar PV cells compared to the existing solar PV panels. This ensures the enhanced power generation from same solar PV panel results in enhanced solar PV panel efficiency. &nbsp;Hence, the major methodology to achieve the continuous solar power generation is generation of continuous light reflections. This methodology is the famous ancient methodology used in many applications such as national astronomy, ionosphere Centre to study the earth ionosphere etc [15-16].&nbsp; There are two possible types of light reflections may generate usually. The two types of light reflections are i) regular light reflections and ii) Irregular light reflections. Each type of light reflections may support enhanced solar power generation for suitable selection of light reflector. The magnitude of solar power of given solar panel depends on the type of reflector material selected for operation and the reflection coefficient of various reflecting materials is observed in table 1. This paper presents the solar panel design with reflection of light proposal for usual light reflection arrangement and instantaneous light reflection arrangement and the experimental arrangements are observed from figure 2 to 4. Also, the solar panel efficiencies are compared to evaluate the light reflection technique and commercial solar panel technique which is observed in table 2. From the experimental results carried out using various experimental setups, the instantaneous regular type of light reflections offers socio-economic continuous power generation with optimal space constraints. Also it is observed during the instantaneous light reflection arrangement experimentation, the AC power generation is observed directly from the solar panel without any inverter application.</p> RAJA NAYAK M Copyright (c) 2021 RAJA NAYAK M 2021-10-17 2021-10-17 1 01 A Comprehensive Study on Electric Vehicle Charging Infrastructure https://spast.org/techrep/article/view/720 <p>The awareness and concerns for energy conservation and environmental sustainability have been increasing over the years globally. In recent years so many research works are going on in this field. In the UN’s Sustainable Development goals, the protection of the planet plays a key role. For centuries, internal combustion engines (ICEs) have powered automobiles, which use fossil fuels and emit harmful emissions. Human activities that produce greenhouse emissions have severely impacted the environment. So, electric vehicles (EVs) have arisen and they possess vast advantages as compared to vehicles powered by ICEs[1].</p> <p>In the present Indian scenario, the government is promoting EVs by implementing the <strong>National Electric Mobility Mission Plan (NEMMP) 2020 </strong>in 2012. In early 2018, the Ministry of Power launched the new National Electrical Mobility Programme to specialize in making the charging infrastructure and a policy framework to line a target of 30% electrical vehicles by 2030 [2].</p> <p>Even though so many advantages are there for EVs, people are deterred to buy them. The major challenge faced by the EVs are related to the charging time and charging infrastructure [3]. There are different charging methods are available for EV such as conductive and inductive. Conductive charging is a wired charging method whereas inductive is wireless. Different types of conductive and inductive charging methods are given in Fig.1.</p> <p><img src="https://spast.org/public/site/images/jishajames/mceclip0.png"></p> <p><strong>Fig.1.</strong> Different charging methods available for EVs.</p> <p>As per the IEC 61851 standards, conductive charging is classified into 4 modes, mode 1 to mode 4. Mode 1 charging is the commonly used one for domestic applications based on the power requirements and economic constraints and it is slow charging. Mode 2 is AC fast charging one but is not common when compared with mode 1. Mode 3 and 4 are the DC fast and ultra-fast charging modes which are rarely used as it affects the lifetime of the battery. Moreover, safety concern is also a factor that reduces the usage of DC chargers. Even though the construction of a conductive charging method is simple, the major limitations in the conductive charging methods are the physical constraints like maximum charging current, power, and voltage. The charging process of EVs can be improved by adopting the technology of Wireless Power Transfer (WPT). WPT technology is based on the induction principle, capacitive based techniques, the principle used in radio frequency waves, and laser power. Magnetic coupling is used as the mode of energy transfer in WPT- based EV battery chargers [4-5]. Since contactless energy transfer is happening in WPT charging of EV, it is more advantageous than conductive charging.</p> <p>Even though there are so many review papers available based on the different charging methods of EV, a paper reviewing both conductive and inductive charging methods along with the industry standards is rarely seen. In this review paper, the authors are focusing on the need and necessity of electric vehicles in the Indian scenario and the different charging infrastructures of EVs including both conductive and inductive.</p> <p>The research works that are carried out in the charging infrastructure of EVs will surely give a great contribution to society. When EVs become affordable and popular, clean energy with proper climate action will occur and sustainable cities and communities will exist in the future.</p> Jisha James Vijaya Margaret Copyright (c) 2021 Jisha James, Vijaya Margaret 2021-09-15 2021-09-15 1 01 SIGNIFICANCE OF RENEWABLE ENERGY SOURCES FOR FUTURE TECHNOLOGIES BUILT ON GEOGRAPHICAL CONDITIONS AND PERIOD OF SEASONS https://spast.org/techrep/article/view/360 <p>An endlessly developing population means a constant rising necessity of energy for their needs.&nbsp; Currently, high usage of energy can’t be repudiated. Energy sources can be generally categorized as conservative and non-conservative energy sources. Major terrible fact of non-renewable sources will ultimately reduce in day by day due to the over usage of energy sources by all human needs. The significance of renewable sources cannot be underrated. The most essential feature while using that, it is not harmful to atmosphere. This paper momentarily explains the significance of non-conservative energy sources extension towards the background of fossil fuel problem. The main importance and usage of non-conservative energy sources for DC and AC applications are presented in this paper and also enlist the maximum power that can be produced by various renewable energy sources based on the geographical conditions and seasons.</p> BHAVANA PABBULETI Jyothi B Tirumala Rao B Copyright (c) 2021 BHAVANA PABBULETI, Jyothi B, Tirumala Rao B 2021-09-17 2021-09-17 1 01 A Review of Optimization Algorithms used in Proportional Integral Controllers (PID)for Automatic Voltage Regulators https://spast.org/techrep/article/view/1642 <p>An automatic control system consists of an algorithm that acts as the brain of the controller.<br>Control system design theory explores the methods of designing a system's algorithm in a<br>way that ensures stability and accuracy [1]. Dynamical systems must be reliable, accurate and<br>stable in closed-loop operation as a central goal in controller design. A well-designed feedback<br>controller can be an investment that saves both money and lives [2]. Furthermore, both<br>optimality and robustness play a vital role in situations of uncertainty. It is more important to<br>generalize a control strategy than to overfit it to specific tasks at one time interval. Automation<br>and intelligent systems rely heavily on feedback systems. Most of the control strategies are<br>still implemented using a PID control, a Proportional-Integral-Derivative strategy because of<br>its easy implementation. As a result, there have been plenty of latest<br>works covering various aspects such as analysis, numerical tools, design, tuning and<br>implementation of PID controllers for different applications. An automatic voltage regulator<br>(AVR) is an important application of the PID controller. The function of AVR system is to<br>regulate the output voltage of a synchronous generator used in the production of electricity.<br>There are many optimisation algorithms used for tuning the parameters of PID controllers in<br>literature. An Enhanced Crow Search-based Assessment (ECSA) of automatic voltage<br>regulator (AVR) optimization [3] is used to address the drawbacks of Crow Search-based<br>Assessment (CSA-PID). ECSA was characterized by improved convergence rates and low<br>values for integral indices, including ISE, IAE, ITAE, and ITSE. In addition to unimodal and<br>multimodal functions, the enhanced algorithm was tested on 23 fixed-dimension multimodal<br>functions as well [3]. All test functions were statistically analyzed and their memory capacities<br>calculated. Several advantages of ECSA include achieving global best with fewer iterations<br>and a shorter development cycle. Although its search strategy did not prove effective and<br>convergence was not assured. The parameters of four different PID controllers are designed<br>using hybrid simulated annealing – Manta ray Foraging Optimization algorithm [4] which is a<br>combination of simulated annealing (SA) and Manta Ray for Foraging Optimization (MRFO)<br>algorithms. The SA algorithm is used to initialize the population of MRFO convergence speed.<br>The PID controller designed using (SA-MRFO) outperforms the other types of the controller<br>design algorithms. A new Fractional Order Fish Migration Optimisation (FOFMO) algorithm is<br>used to optimise the PID controller parameters [5] that mimic the swim and migration<br>behaviour of fish biology. Compared to the original FMO, FOFMO is superior, and FOFMOtuned PID controllers have stronger performance than other contrast algorithms [5].The goal<br>of this paper is to give a concise overview of optimization algorithms used in PID controllers<br>for automatic voltage controller applications.<br>&nbsp;</p> ATHIRA SIVANANDHAN Aneesh V Copyright (c) 2021 ATHIRA SIVANANDHAN, Aneesh V 2021-11-06 2021-11-06 1 01 New magnetic coupling pad with circular geometry for wireless power transfer applications https://spast.org/techrep/article/view/1639 <p><strong>Abstract </strong>&nbsp;</p> <p>With features like convenience, fully automatable and safety, Wireless Power Transfer(WPT) technology have the ability revolutionize the EV charging infrastructure[1, 2]. The difference between plug-in charging and wireless charging is a magnetic coupler, which transfers power without using cables. The basic structure of WPT shown in the fig. 1. The performance of the WPT operation mainly depends on the coil design, core and shielding. Researchers introduced different types of magnetic coupler designs for enhancing magnetic power transfer capabilities [3].</p> <p><img src="https://spast.org/public/site/images/maheshaganti/mceclip3.png"></p> <p><strong>Fig.1.</strong> Basic structure of inductive wireless charging system.</p> <p>In particular multi coil structures like DD, DDQ Bi polar pad, quadruple pad and many more proposed as a solution to challenges like low coupling factor, low mutual inductance and misalignment. Furthermore, these multi coil pads shown the tolerance towards movement of vehicles that is more useful in dynamic wireless charging systems (charging of EV while moving). Among the all the pads circular pads have same misalignment tolerance in all directions and they have simple construction and easy to operate. Due to their non-directional behaviour, EV can approach towards charging point from different directions which provides flexibility for driver. These all features suitable for Static Wireless Charging (SWC) applications (charging of EV in stationary position). Therefore, despite having low mutual inductance and coupling factor compared to similar sized pads with identical air gap, circular pads are still mostly used geometric structure for SWC applications[4] [5].</p> <p><strong><img src="https://spast.org/public/site/images/maheshaganti/mceclip2.png"><br>Fig.2.</strong> Proposed coil model.<br>Considering the features of circular geometry. In this article, a new pad proposed to enhance the power transfer capabilities of circular shaped magnetic pad. Proposed model consist of multiple coils to gain more mutual inductance and misalignment tolerance operation. The proposed pad shown in fig. 2, which consisting of two coils one is circular shaped DD coil and another one circular coil acts as a quadrature coil.</p> <p>Initial analysis of proposed pad done in Ansys Maxwell 3D FEA simulation software with different approaches and compared with conventional circular pad. Approach-1: proposed pad as transmitting coil and circular pad as a receiving coil.Approach-2 proposed pad(position of quadrature coil changed) as a transmitting coil and circular coil in receiver side.Approach-3 is proposed model as transmitter and Factors considered for the analysis are mutual inductance and similar air gap (50 mm) and simulation is done without using ferrites. Model diagrams of different approaches shown in fig. 3. Table 1 presents sel af and mutual inductances of different approaches in that proposed pad utilized as a transmitter with different receiving coils and they are compared with circular model (transmitter and receiver both are circular coils. Fig .4 shows the magnetic flux path in circular model in FEA simulation.</p> <p><img src="https://spast.org/public/site/images/maheshaganti/mceclip1.png"></p> <p><strong>Fig.3.</strong> Different approaches followed in simulation.</p> <p><img src="https://spast.org/public/site/images/maheshaganti/mceclip0.png"></p> <p><strong>Fig.4.</strong> Magnetic flux path in FEA simulation.</p> <p><strong>&nbsp;</strong></p> <p><strong>Table 1. </strong>Comparison of different approaches</p> <table> <tbody> <tr> <td width="121"> <p><strong>50mm air gap</strong></p> </td> <td width="110"> <p><strong>Circular model</strong></p> </td> <td width="119"> <p><strong>&nbsp;Approach-1</strong></p> </td> <td width="119"> <p><strong>Approach-2</strong></p> </td> <td width="97"> <p><strong>Approach-3</strong></p> </td> </tr> <tr> <td width="121"> <p><strong>Mutual Inductance</strong></p> </td> <td width="110"> <p>327nH</p> </td> <td width="119"> <p>303nH</p> </td> <td width="119"> <p>357nH</p> </td> <td width="97"> <p>127nH</p> </td> </tr> <tr> <td width="121"> <p><strong>Self-inductance of primary</strong></p> </td> <td width="110"> <p>4.4µH</p> </td> <td width="119"> <p>8.7µH</p> </td> <td width="119"> <p>9µH</p> </td> <td width="97"> <p>8.7µH</p> </td> </tr> <tr> <td width="121"> <p><strong>Self-inductance of Secondary</strong></p> </td> <td width="110"> <p>4.4µH</p> </td> <td width="119"> <p>4.53µH</p> </td> <td width="119"> <p>4.53µH</p> </td> <td width="97"> <p>4.50µH</p> </td> </tr> </tbody> </table> <p>&nbsp;</p> <p>By observing table 1, the approach 2 offers better performance than the conventional circular model in terms of mutual inductance. This method is useful in static charging applications to improve the charging time and power transfer capability. Adding of compensation and ferrites improves the mutual inductance and coupling factor.</p> mahesh Bharatiraja C Copyright (c) 2021 mahesh, Dr.C.Bharatiraja 2021-10-08 2021-10-08 1 01 Development of Grid Tied Inverter for Indian Grid and Operating Environmental Condition https://spast.org/techrep/article/view/1537 <p>Solar Photovoltaic (PV) technology is one of the renewable energy source technologies to realize the shift to decarbonize energy supply because of availability of safe, limitless, free and reliable long-term sources of power. It is projected to emerge as most appropriate technology for an alternate electricity source in the future.</p> <p>In India, ample amount of solar energy is available in the form of heat and irradiation. PV modules/ cells are instruments to convert this solar energy to DC energy. Storing this electric energy is a big challenge. Batteries and Ultracapacitors are used to store this energy. However, they have certain limitations with regard to size, cost and life. Grid&nbsp;interconnection is one of the best solution. In sun hour, PV system supply additional energy to satisfy peak demand and in night hour consumer can take energy from grid. This system has the&nbsp;advantage&nbsp;of effective utilization of generated&nbsp;power&nbsp;because of absence of storage losses.</p> <p>Various control techniques have been developed and reported so far for the interconnection of PV system to the utility grid.&nbsp; Dynamic hysteresis current control technique, current controlled techniques with power quality (PQ) improvement control strategies, active and reactive power control techniques. Synchronization is also an important issue in integration of renewable energy sources into the utility grid [1].</p> <p>Conventional synchronous reference frame phase locked loop (SRF-PLL) based synchronization techniques are used in detecting the phase angle of the grid voltages. Improvements have been done to achieve fast and accurate synchronization under distorted grid conditions by Phase Locked Loop (PLL) algorithms and symmetrical component extraction methods intended for grid-connected power electronic converters. Vector control based techniques are Natural (a-b-c), stationary and rotating coordinates (d-q), Dual Second Order Generalized Integrator (DSOGI-PLL), Dual Virtual Flux – both in stationary coordinates, rotating d-q coordinates which is Dual Synchronous Reference Frame PLL (DSRF-PLL) [2-4]. In these techniques, continuous monitoring of instantaneous grid voltage is required. In [5], SCR based converter does not required synchronisation but operates at poor power factor.</p> <p>In proposed technique, Voltage source converter continuously follows the grid voltage. A simple R-C circuit is used to create phase shift between grid voltage and output of voltage source converter. From this R-C circuit, a modulating signal is derived to inject maximum power to grid. This technique can be implement with Microcontroller/ Digital signal processor with less computational time and programming space.</p> <p>The main objectives of proposed scheme is to design single phase, 3kW, 230 V PV system to connect to 230 V, 50 Hz grid which is available to house. This research will provide affordable and reliable PV system.</p> <p>Block diagram of proposed scheme is shown in Fig. 1. Current (I) through R-C circuit leads to Supply voltage V<sub>S</sub>. The voltage drop across the resistance is V<sub>R</sub>. The microcontroller reads these voltages and generates modulating signal V<sub>I</sub> as shown in Fig. 2. The injected power p is given by</p> <p>Where &nbsp;&nbsp;V<sub>g</sub>= grid voltage ,V<sub>i</sub>= output Voltage of Voltage Source Converter governed by V<sub>I</sub>,&nbsp; δ=angle between V<sub>g</sub> and V<sub>i </sub>&nbsp;which is derived by microcontroller. The angle δ controls the power injected to grid which can obtain maximum power injection to grid.</p> <p>Fig. 3&nbsp; shows the generated solar power in watt with given irradiance level 700 w/m<sup>2</sup> and peak irradiance at sunny period i.e 1000 w/m<sup>2</sup> over a specified period . The irradiance level changes to 1000 W/m<sup>2</sup> after 6 sec. The maximum power extracted by P&amp;O maximum power point tracking MPPT algorithm from PV panel is 3013 watt and 2100 watt at irradiance of 1000 w/m<sup>2</sup> and 700 w/m<sup>2</sup> respectively. The corresponding voltage of PV panel to obtain maximum power is 373.5 V<sup>. </sup></p> <p>Fig. 4a shows the maximum tracking point alpha α after P&amp;O MPPT at given two irradiance level 700 w/m<sup>2</sup> and 1000 W/m<sup>2</sup> respectively. As α oscillate near the maximum tracking point, hence, input inverter power and grid power also fluctuate as shown in Fig. 4b. The injected current to grid is shown in Fig. 4c. When rate of change of power with respect to voltage dp/dv (shown in Fig. 4d) is zero, the maximum point is tracked by MPPT.</p> <p>Fig. 5 shows the zoom version of AC output voltage of 1-phase three level inverter at irradiance 1000 W/m<sup>2</sup>.The r.m.s value of output voltage observed is 276.1 V. Fig. 6 shows the single phase voltage at grid side in zoom version. The grid side voltage is maintained at r.m.s value of 230V, 50Hz and it is connected to output of inverter through inductive reactance of 0.8Ω. Fig.7 shows zoom version of output voltage of synchronization circuit. It shows grid voltage and modulating signal which generates gate pulses for inverter. This modulating signal leads by an angle δ to grid voltage.</p> <p>This research will provide affordable and reliable PV system solution to generate power at the rooftop of house. There is always sun light on the half of the earth globe. The international grid can collect and provide solar power to all countries as demand of electric power is increasing due to advent of digitalization, automation and electric vehicle.</p> Manjusha Palandurkar Copyright (c) 2021 Manjusha Palandurkar 2021-10-07 2021-10-07 1 01 Power Quality Enhancement Using Multi-Level Inverter with UPQC and Robust Back Propagation Neural Network Strategy https://spast.org/techrep/article/view/2967 <p>More pollutants for coal, oil, natural gas and others, a viable alternative to sustainable and renewable energy sources, have increased significantly over the past decade. These can then be seen as the first step in the global movement to reverse the problems resulting from slow climate change. Therefore, in this work, use solar power source-based power quality improvement in a system. The main aim of this work is multilevel inverter associated UPQC for power quality enhancement. In this work, multilevel inverters are used in a series shunt controller for producing accurate sinusoidal wave shape. The series controller is connected to the grid side for grid power quality improvement. In this work, grid side voltage sag/swell was reduced by a series controller. The advantage of the proposed system is the high-efficiency enrichment of quality power. The MATLAB/Simulink environment verifies the simulated results of the proposed system.</p> A Hema Sekhar S. Lakshmi Kanthan Bharathi N. Ahamed Hussain Asif P. Veera Manikandan Copyright (c) 2021 A Hema Sekhar, S. Lakshmi Kanthan Bharathi, N. Ahamed Hussain Asif , P. Veera Manikandan 2021-11-05 2021-11-05 1 01 Appraisal of Available Transfer Capability Determination Methods in Competitive Electricity Market https://spast.org/techrep/article/view/396 <p><span style="font-weight: 400;">The existing power market is contentiously promoting sustainability and competitiveness in the electricity industry. It has raised the transmission networks' transfer capacity as an emerging area for researchers. The electricity production units and consumers share the same transmission network. All stakeholders try to generate power from cheaper sources to make more significant profit margins. This situation creates transmission congestion, violation of voltage and thermal limits, system security threats. The accurate measurement and optimal use of the available transfer capability (ATC) shall resolve this issue up to some extent. Thus, efficient evaluation of ATC is needed to ensure system security, and it provides an open and trending research topic. This article presents a review of the various techniques for ATC determination and provides the characteristics, practices, and features of the methods. This analysis demonstrates the issues of ATC evaluation techniques and provides the research areas to the researchers.&nbsp;</span></p> <p><br><br></p> <p><strong>Figure 1: ATC Related Parameters &amp; Limitations</strong></p> <p>&nbsp;</p> <p><span style="font-weight: 400;">Figure 2: An AI training model for ATC estimation</span></p> <p><br><br></p> <p><strong>Table I: ATC determination techniques Comparison</strong></p> <table> <tbody> <tr> <td> <p><strong>Technique</strong></p> </td> <td> <p><strong>Computation</strong></p> </td> <td> <p><strong>Data Size</strong></p> </td> <td> <p><strong>Complexity</strong></p> </td> <td> <p><strong>Accuracy</strong></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">LAM</span></p> </td> <td> <p><span style="font-weight: 400;">Fast</span></p> </td> <td> <p><span style="font-weight: 400;">Small</span></p> </td> <td> <p><span style="font-weight: 400;">High</span></p> </td> <td> <p><span style="font-weight: 400;">Accuracy cannot be guaranteed</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">RPF or CPF</span></p> </td> <td> <p><span style="font-weight: 400;">Moderate</span></p> </td> <td> <p><span style="font-weight: 400;">Large</span></p> </td> <td> <p><span style="font-weight: 400;">Low</span></p> </td> <td> <p><span style="font-weight: 400;">Accurate compared to LAM.</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">OPF&nbsp;</span></p> </td> <td> <p><span style="font-weight: 400;">Moderate</span></p> </td> <td> <p><span style="font-weight: 400;">Large</span></p> </td> <td> <p><span style="font-weight: 400;">High</span></p> </td> <td> <p><span style="font-weight: 400;">Optimal results are not guaranteed</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">AI Approach</span></p> </td> <td> <p><span style="font-weight: 400;">Very fast</span></p> </td> <td> <p><span style="font-weight: 400;">Very Large</span></p> </td> <td> <p><span style="font-weight: 400;">Low</span></p> </td> <td> <p><span style="font-weight: 400;">Highly accurate</span></p> </td> </tr> </tbody> </table> <p><br><br></p> Shweta Meena Copyright (c) 2021 Udit Mamodiya 2021-09-15 2021-09-15 1 01 Design of Mono Stage LUO Converter for Electric Vehicles Charging System https://spast.org/techrep/article/view/2699 <p>The Electric Vehicle (EV) is gaining more attraction in recent years due to the reduction of pollution and increase in fuel costs. The commercialization of EV is still struggling to find the better solution for charging facilities due to lack of charging station and time required for charging the EV. The research in charging infrastructure is increased in recent years to increase the charging facilities [1]. The Light Duty EVs has huge demand among the customers, but due to lack of charging facilities the distributors and consumers are worried to utilize the EV in their daily routine. The Government of India has created the standards for EV charging and battery swapping technologies to avoid the confusion for the charging station providers.</p> <p>In [2], a charger with coupled winding structure is designed that reduced the current stress and switch voltage. But this arrangement results in the complexity of isolation transformer and makes it bulky. The voltage stress in semiconductor devices is high with the singe stage single switch configuration that results in lower efficiency [3]. The non-isolated negative output Luo Converter is discussed in [4], which gives better performances like lower input and output ripple, higher voltage conversion ratio, etc. The Luo converter is broadly utilized in super-lift, re-lift and ultra-lift applications [5]. The charging station with 12 kW along with 6 kWh capacity of the battery is designed in [6]. The converter proposed in [7] will operate in both buck and boost mode simultaneously. In the resonant LLC converter that eliminates the switching losses in ZVS mode is fed by the CUK converter. The battery supplies the input to converter which is stabilized and improved with the help of inductor [8].</p> Ramanathan G Bharatiraja c SANTHA KUMAR C JOSIAH LANGE MUNDA Copyright (c) 2021 Ramanathan G, Bharatiraja c, SANTHA KUMAR C, JOSIAH LANGE MUNDA 2021-10-19 2021-10-19 1 01 An Overview of SOC estimation in Li-ion batteries with Direct Measurement methods. https://spast.org/techrep/article/view/1950 <p>The recent increase in demand for new and improved battery technologies and energy storage <br>devices has accelerated due to the recent electric vehicle market surge. This also includes <br>better battery management systems to allow safe, efficient, long-lasting use of the batteries. A <br>better battery management system allows for a better system for the required application, <br>allowing the batteries to function at their best potential. An extremely crucial parameter for <br>this is the SOC (State of Charge) Estimation, which is the measure of the ratio of the <br>available capacity to the maximum possible charge that can be stored in the battery.<br>The state of charge (SOC) is an indication of the available battery capacity. It is one of the <br>most crucial aspects to monitor to enhance the efficiency and endurance of lithium-ion <br>batteries. <br>There have been several methods for estimating SOC, mainly categorized into two types: <br>i)Direct measurements, ii) Indirect Measurements. <br>i) Direct measurement methods, which include; a) Open Circuit Voltage method b) Terminal <br>Voltage method b) Impedance spectroscopy method d) Coulomb counting method and ii) <br>Indirect measurement methods, which include several new methods such as a) Adaptive <br>artificial intelligence method which include Fuzzy based Neural Networks (ANFIS) and <br>Artificial Neural methods, etc., b) Adaptive Filter Based Methodologies which include <br>Kalman Filter Based Estimation methods, etc.. and c) Model-Based Estimation methods <br>which include Electrochemical methods and Electrical circuit methods. <br>This paper primarily focuses on The direct measurement methods of SOC estimation and <br>compares the options to highlight the drawbacks and advantages of each. <br>Direct SoC estimation methods analyze and measure physical battery characteristics like the <br>voltage, current, and temperature, then estimate the SoC using an equation or relationship[1]<br>In Direct Measurement methods, the primarily used ones are Coulomb Counting (also <br>known as the ampere-hour balancing method), which currently happens to be Because it is <br>the most precise methodology for short-term calculations, it is the most often used method for <br>SoC estimate. SoC is described using the CC method as [1-2]:</p> <p><img src="https://spast.org/public/site/images/manthan_sharma/mceclip0.png"></p> <p>Here, SoC(t) is the starting or initial state of charge, Cn is the nominal capacity, and the term <br>Ibat is for the charge/discharge current.</p> <p>This paper also significantly emphasizes a relatively newly discovered method known as <br>Event-Driven Coulomb Counting. This method enhances the conventional coulomb countingbased direct assessment method, applicable for online realizations required for electric <br>vehicles and drones [3-4]. This new technique provides ways for improving the <br>computational effectiveness of the conventional coulomb counting technique, which is <br>accomplished by intelligently adding event-driven processing methodology to the suggested <br>solution. This technique employs an Event-Driven Analog to Digital Converter, which <br>successfully records desired battery cell characteristics such as current and voltage. This <br>reduces the computational cost of the post SOC estimate step substantially. [3-8] This <br>method uses Equivalent Circuit Modeling (ECM), which then uses a Data Acquisition and <br>Measurement system to record the parameters, which then carries out Event-Driven Coulomb <br>calculation on the individual recorded values. Other Coulomb Counting methods use <br>different applications such as Combination of Coulomb Counting and Dynamic Model With <br>Adjusted Gain, Peukert’s Law and Coulombic Efficiency, and other Enhanced methods. <br>Other methods include: Open circuit Voltage Method: In the several SoC estimating <br>techniques, open-circuit voltage (OCV) is widely utilized to estimate the state-of-charge <br>(SoC). The connection between the OCV and the SoC, on the other hand, cannot be the same <br>for all batteries. Because the traditional OCV–SoC varies amongst batteries, there is a <br>difficulty in that the OCV–SoC relationship must be measured to correctly estimate the SoC.<br>To alleviate the inconsistency in traditional OCV–SoC, an estimating technique based on the <br>dual EKF with a modified OCV–SoC is introduced. The OCV–SoC relationship and the dual <br>EKF method are explained, along with experimental results. The suggested approaches <br>simplify the implementation of the dual EKF and allow for simultaneous estimation of the <br>SoC and capacity. The dual EKF estimate results meet the requirements to within ±5%[9].<br>The third method in Direct Measurement is The terminal voltage technique, which is <br>primarily based on the terminal voltage decreasing due to internal impedances when the <br>battery is discharging; thus, the battery's electromotive force (EMF) is proportional to the <br>terminal voltage. Because the EMF of the battery is approximately linearly proportional to <br>the SOC, the terminal voltage of the battery is likewise linearly proportional to the SOC. The <br>terminal voltage technique has been used at various discharge currents and temperatures.[10]<br>Lastly, the method known as Electrochemical Impedance Spectroscopy (EIS) can be <br>applied to decipher the electrochemical processes inside of the Li-ion battery. We can create <br>an Equivalent Circuit Model (ECM) using the data from the EIS and knowledge of the <br>physical and chemical processes inside of the battery. Also, Various methods based on <br>electrochemical impedance spectroscopy(EIS) have been put forward to estimate SOC, SOH, <br>and internal temperature, which are key states to character battery condition and maintain <br>proper use of batteries in vehicles. EIS is a basic method to study an electrochemical system, <br>including batteries [11-14].<br>However, EIS is not a viable solution for estimating SoC in EV batteries because of its <br>significant drawbacks. The bulky and costly EIS measurement equipment can’t be used in <br>vehicles directly, though methods based on EIS are effective. On-board EIS measurement <br>system design can only be seen in a limited number of works of literature [11-17]</p> Manthan Sharma Siva Ram Geda Copyright (c) 2021 Manthan Sharma, Siva Ram Geda 2021-10-09 2021-10-09 1 01 An Impudence Source Inverter Three-level Pulse Width Modulation for Common-Mode Voltage Reduction in DC-MLI Induction Motor Drive https://spast.org/techrep/article/view/2905 <p>Three phase induction motor drives is excellent choice for variable - speed drives capabilities, are commonly applied according to industrial needs and power facilities. On other hand development of power electronic converters and their switching technologies are also growing in a faster manner. As a result, silicon carbide (SiC)/gallium nitride (Gn) based rapid switching devices with pulse width modulated inverters are used to construct the variable frequency drive (VFD) system to satisfy the drive's full capabilities. However, issues about common-mode voltage (CMV) are prevalent in VFDs, which are primarily augmented by the switching devices' faster switching characteristic (dv/dt) [1]. For VFDs, the CMV causes concerns like leakage current, bearing current, and conducted emissions. In other direction conventional voltage source inverters are replaced by Impudence Source Inverter (ISI) as it has the DC – link voltage boosting capabilities. However the CMV reduction in complex in ISI as it have a shoot- through state which is needed all the CMV producing voltage switching vectors. Hence the ISI based AC drives are using predominant active and passive CMV filtration are the most broadly. To eliminate the CMV in wide-range frequency operations, active attenuation methods use a correct blend of inductors, capacitors, and switches, together with appropriate management mechanisms. Active techniques, on the other hand, are difficult to create (phase requirement and attenuation are requires accurate tuning over the wide range of frequency). Active methods have a resiliency that is determined by the drive rating. Active switches also cause additional power loss, reduced dependability, and increased control complexity. Nonetheless, this methods takes larger portion in the drive and the smaller parasitic capacitive (Cwf) impedance (choke output impedance) appear across it. Hence PWM base CMV elimination is concentrated; hence the filtrations cost and space and weight of the drive can be reduced. The amplitude of three-phase three-level DC IS- MLI CMV generated for the period of the switching period will be less than or equal to VDC/3 in any PWM scheme that uses all available switching vectors [2].</p> <p>Numerous studies have been conducted based on this concept in order to discover a solution to the CMV mitigation challenge in DC-MLI. However the DC IS- MLI CMV reduction is not yet attempted [3]. The amplitude of the CMV generated for the period of the switching period will be less than or equal to V<sub>DC</sub>/6 in any PWM scheme that implements reference vector by series of useful vectors. Numerous studies have been conducted based on this concept in order to discover a solution to the CMV mitigation challenge [4]. The use of three medium vectors (M<sup>3</sup>V) is a way for keeping the CMV constant. However, these solutions could only work with a lower modulation index, which has an impact on the fundamental output voltage. The maximum voltage output obtained is only 66 percent of V<sub>DC</sub>, which is lower and affect the inverter output voltage requirement. Hence this paper the ISI DC MLI new PWM method is proposed the partially eliminating the CMV without affecting the DC-link utilizations. The Figure-1 and Table-1 show the switching vectors and CMV of inverter.</p> Suresh kumar Annam R.K Pongiannan Copyright (c) 2021 Suresh kumar Annam1, R.K Pongiannan 2021-10-21 2021-10-21 1 01 DETECTION OF SHADING AND ABNORMAL CONDITIONS IN A PHOTOVOLTAIC ARRAY USING FUZZY LOGIC CONTROLLER https://spast.org/techrep/article/view/182 <p>Among several renewable energy resources, Solar has great potential to solve the problem of shortage of nonrenewable energy resources. Now-a-days a greater number of houses are installed with PV system. As installation increases monitoring the system is a need to protect the system from weather and atmospheric conditions. Environmentally friendly power is free, spotless and interminable, for example, sunlight based photovoltaic (PV), wind energy, flowing energy, and so forth… and the utilizations of sustainable assets have been respected by all clients [1, 2]. In electrical business sectors, PV is becoming quickly because of their benefits like expense decrease of sun powered board, life time of the board, simple establishment and support [3]. In that support has become the more significant part for extricating the most extreme energy from the sunlight based board for the duration of the existence season of the module. By appropriate upkeep, Maximum Power (Pm) extraction is guaranteed by Maximum Power Point Tracker (MPPT). In writing, bunches of papers are introduced in the space of most extreme force point following [4-6].Throughout the most recent couple of many years, the utilization of PV frameworks has spread quickly everywhere on the world in various applications, from space to the private, business, and modern applications [7]. High utilization of PV boards has brought high PV segment disappointment rate too. This high rate is a direct result of numerous reasons, for example, cut off modules; an open circuit in various strings, and so forth These disappointments extraordinarily impact on the working proficiency of the PV age frameworks and the presentation of the PV framework work. In this way, numerous kinds of examination and improvements in ref. [8] gained great headway utilizing on-line deficiency determination to build framework unwavering quality and execution by early issue discovery.Various shortcomings can be classified into impermanent and perpetual blames in PV clusters, and both are liable for lessening the yield power and sun based energy created contrasted and solid working conditions [9]. Albeit the brief flaws happened for a brief period truly, the security gadgets need to segregate this condition from perpetual shortcoming conditions for forestalling incorrectly closures [10]. In this way, to decrease the inaccessibility time, increment the steadiness and effectiveness of PV frameworks, distinctive issue determination and location strategies are expected to guarantee the progression of sun based age [11]. There are many shortcoming location techniques utilized in the GCPV frameworks. In [12], programmed oversight by OPC innovation based observing by figuring Voltage and Current Ratios VR, and IR is utilized to distinguish the various flaws. Some different strategies, for example, in ref. [13,14] are executed dependent on the constant natural conditions and some PV boundaries, notwithstanding, the disadvantage of this strategies is the significant expense of hardware. Also, Partial Shading PS in the GCPV plant utilizing measurable techniques is talked about and approved utilizing Ratios VR&amp; PR [15,16].As of late, various flaw determination strategies dependent on man-made reasoning methods are embraced to build the identification rate and right grouping, for example, Fuzzy Logic Control FLC [13, 16], Neural Network [8,17], both Neural and FLC [16,18], Genetic Algorithm [19], or MATLAB [10, 12]. As of now, the FLC is broadly utilized with GCPV frameworks, Such as [16, 18] which introduced FLC to distinguish the flawed modules, yet couldn't separate between open circuit and short out deficiencies.The work introduced in this paper is to acquaint another procedure with recognize and analyse the various kinds of flaws happening in the PV power plants utilizing sugeno FLC strategy. This strategy is utilized as a counterfeit technique to expand the exactness of flaw recognizable proof and quick conclusion. The proposed discovery strategy relies upon the examination set of two information proportions which are Current Ratio IR, and Voltage Ratio VR. Computing these proportions is performed utilizing the deliberate and mimicked under ordinary and defective conditions. The flaw discovery technique is executed utilizing FLC-based strategy and MATLAB Simulink device to distinguish the sort of the shortcoming. The chose blames in this work are PS, PS with bypass diode failure, open circuit, short circuit, snow falling, and bird or tree leaves dropping on PV plant.</p> <p>This paper proposes a novel technique for fault detection in the photovoltaic array by using fuzzy logic controller. By using a simulation model, the voltage and current variation under eight different faults. They are open circuit, short circuit, partial shading, bypass diode failure, snow falling, bird or tree leaves dropping faults. The simulated attributes are given to the fuzzy logic controller to predict the type of fault occur in or between photovoltaic modules.</p> Nageswara Rao Gudipudi Copyright (c) 2021 Nageswara Rao Gudipudi 2021-09-08 2021-09-08 1 01 A Single Stage SEPIC Converter for Electric Vehicles Charging System https://spast.org/techrep/article/view/1589 <p><strong>&nbsp;</strong>In recent years, the combustion engine vehicles are replaced with Electric Vehicles (EV) as the pollution is less. Though the EV has been commercialized, charging facilities is the biggest hurdle for consumers to use EV. Lack of charging station is the major problem for consumers to utilize EV in their day-to-day life. Thus, the research has been increased in charger for EV. In this regard, the charging scheme with constant current (CC) and constant voltage (CV) is introduced in [1] where the battery life is been affected due to the presence of ripple in charging current. This ripple is reduced with the help of Dual Active Bridge (DAB) topology, which has inbuilt zero current and voltage switching where the power is transferred from primary to secondary bridge with the help of leakage inductor [2]. At present, single port charging station is mostly available in practice where only one EV can be charged at a time. This increases the waiting time for customers to charge their vehicle. A on-board charger (OBC) is introduced to reduce the congestion of EV at the charging station. The size of OBC is minimized by introducing the voltage source converter at the front end in the place of rectifier cum boost converter. The back end has multiple options of DC/DC converter in which DAB is preferred for the OBC [3]. The control technique for the OBC with DAB topology is focused in [4] for obtaining the smoother operation and various DC/DC converter is discussed for the reduction of converter size. The waiting time of the consumer can be reduced by proper scheduling and forecasting process as discussed in [5].</p> <p>A high gain DC-DC converter with the combination of boost and CUK converter is designed which provides better efficiency [6]. Though the efficiency is high, it requires two converters to charge the EV. In [7], only SEPIC converter is used for designing the OBC. In this topology, the frond end consists of rectifier with AC supply which provides DC output to the SEPIC converter at the back end. In the proposed topology, the AC input with rectifier is replaced with PV panel which provides direct DC supply. This reduces the number of power electronic components which in turn minimizes the power loss. Two SEPIC configuration is used in isolated condition. The isolated SEPIC configuration gives the multi-step current output which provides the different charging condition such as fast and slow charging.</p> Ramanathan G Bharatiraja C Copyright (c) 2021 Ramanathan G, Bharatiraja C 2021-10-01 2021-10-01 1 01 Upgradation of Smart Grid Power Utility with Vehicle-to-Grid Technology by using Smart Energy Management System https://spast.org/techrep/article/view/862 <p>The Smart Grid (SG) station is a unique manner, which needs close collaboration between production, transmission and distribution systems. Over the past times, extreme greenhouse gases result more sustainable energy system, which involves integration of renewable sources such as solar and wind energy into the distributed power systems. These renewables offer more prospects for the end-users to contribute in energy distribution system and make this further effective, where the new "Smart Grid" idea appears. This new grid offers: a two-way communication between the source and load, incorporates renewable sources to the generation system and provides reliability and durability throughout the generation for final energy consumption. The lack of reliability in continuing production shows the challenges to deploy renewable sources in a real-time energy distribution system. Different storage options can solve this lack of reliability problem but it consumes electricity and create significant costs and carbon emissions. An alternative is to use Electric Vehicles (EV) and electric vehicles with a two-way power transferability (Grid-to-Vehicle and Vehicle-to-Grid, as temporary power storage devices. A perfect fit can reload the vehicle batteries from renewable sources and start-up batteries, when the grid network needs more. It significantly reduces the carbon emissions from energy and transport sector, which will increase the reliability of renewable use. However, participation of these vehicles in grid discharge program is naturally limited by the concern of vehicle owners on the basis of battery life and income. A big challenge is to find ways to make integration of more efficient and economical vehicles for vehicle and public service owners. The proposed method focuses on problems like less average life of vehicles, unloading of the grid, to make energy transfer a two-way economically viable, to increase participation rate of vehicles and to make more reliable and durable the entire system. Different techniques are already implemented to integrate EV’s into the power system, but this proposal includes smart Energy Management System (EMS) to integrate the EV’s with the grid properly to increase the power utility according to the load demand at different conditions. This gives the economic benefits to use vehicle batteries in second life in the form of energy storage units, which reduces storage energy costs for network operators and income creation for vehicle owners.</p> Pallavi Gajbhiye Copyright (c) 2021 Pallavi Gajbhiye 2021-09-16 2021-09-16 1 01 Simulation of the Effect of Frequency and Aspect Ratio on Ribbon Bond Wire Performance https://spast.org/techrep/article/view/258 <p>Power electronics has become significant research area because of efficient electronic devices and power generation from renewable sources. The advances in power electronics increase the operating frequency of the power semiconductor devices in the range from 2 kHz to 200 MHz and current range from mA to MA [1]. This leads to significant challenge in power electronics packaging. Bonding wires are important component in packaging which is used to make interconnections between power semiconductor devices and other components such as integrated circuit, inductors, capacitors etc, [2]. The bond wire is made of materials such as aluminium, copper, silver and gold. Even though copper is less reliable due to its susceptibility to corrosion and hardness, it is most preferred because of cost [3, 4]. Round wires and ball bonders and commonly used by industries. Recently, ribbon bond wires become more popular because of reduced cross section area while maintaining or increasing the surface area [5, 6]. For high frequency applications, the proper design of bond wire is required in order to deduce the voltage drop and power loss across the bond wire [7]. At high frequencies, the resistance of the bond wires increases significantly as the result of skin effect.&nbsp; This significantly cause power loss and reduces the overall system efficiency [8]. The frequency dependent impedance and power loss are essential in the design of bond wires in power electronics packages. In this work, the simulation of the effect of frequency and aspect ratio on the performance of the ribbon bond wire is presented. A copper ribbon bond wire is considered and 2D FEM electromagnetic simulation is carried out. The current density, resistance and power losses obtained for power frequency using simulation are compared with the calculated values. The performance parameters are obtained for the frequency range from 200 Hz to 20 MHz. Also, simulation is carried out to obtain the performance of the ribbon bond wires for the aspect ratios 6, 24, 54, 96 and 150.&nbsp;</p> Femi Robert Muskan Puri Sanyukta Nair Copyright (c) 2021 Femi Robert, Muskan Puri, Sanyukta Nair 2021-09-11 2021-09-11 1 01 CAPACITY CREDIT BASED RELIABILITY ANALYSIS IN THE POWER SYSTEM CONSIDERING RENEWABLE ENERGY GENERATORS https://spast.org/techrep/article/view/965 <p>The rapidly increasing power demand gives the needs of attention in renewable energy generation. But due to high uncertainties, all-time integrating renewable power becomes highly unbelievable. This situation is creation reliability evaluation and cost evaluation of power system with consideration of renewable energy generation. This paper mainly deals with the reliability evaluation based on mathematical and probabilistic techniques. The proper FOR (Forced Outage Rate) value should be taken for reliability evaluation in an efficient way. This can be done by the mathematical formula for a year. This paper deals with the model consecutive replacing of conventional generation to renewable generation and calculation of capacity credit value in the test system using recursive formulae. The capacity credit value is calculated from the ELCC value.</p> <p>&nbsp;</p> shankar Amalaraj Copyright (c) 2021 shankar Amalaraj 2021-09-18 2021-09-18 1 01 GA-ANN based Fault Identification in a Micro Grid https://spast.org/techrep/article/view/2677 <p>Designing and maintaining a reliable distribution network with multifaceted nonlinear loads is the key challenge to electrical design engineers. Identifying the fault type in a complex system is intricate. Many research works are carried out to reconfigure the distribution network with sophisticated control schemes to achieve the enhanced reliable network operation. Each control scheme has its advantages and disadvantages. The complete knowledge is essential in the selection of a suitable control scheme to comply with the reliable network in a socio-economic way for various faults scrupulously, failing which causes severe damage on both the network side and consumer side. In this article, micro grid considered is 33 bus distribution networks along with DG (Distributed Generation). Article presents the genetic algorithm for optimal location of DG and artificial intelligence type control scheme to identify the fault type in the radial 33 bus distribution network. The proposed scheme uses Genetic Algorithm (GA) and artificial neural network (ANN) techniques to identify fault type using MATLAB 2014b.</p> Syed Abdul Mujeer M.Raja Nayak Copyright (c) 2021 Syed Abdul Mujeer, M.Raja Nayak 2021-10-21 2021-10-21 1 01 Piezoelectric https://spast.org/techrep/article/view/312 <p>In general, everyone wants new technology to survive in this competitive world. In the <br>segment of instrumentation, the transducer is one of the electrical devices well suited for <br>domestic and small-scale industry applications. One of the new technologies in the <br>transducers such as piezoelectric transducer is widely used in the electrical and mechanical<br>field applications. So in this review paper, various piezoelectric materials are discussed <br>along with their physical properties and benefits. Current applications with piezoelectric <br>transducers are discussed and analyzed based on the physical properties of these <br>piezoelectric materials.</p> B Thirumala Rao Anand Copyright (c) 2021 B Thirumala Rao Anand 2021-09-14 2021-09-14 1 01 Different Power Quality Issues of the Energy Power System with Their Analysis and Mitigation Techniques https://spast.org/techrep/article/view/537 <p><span style="font-weight: 400;">The power systems have the utilization of the power electronics devices for electric power supply becomes a very common trend. These power electronics devices work like as a nonlinear loads and produce the distortion in the system which introduces unwanted harmonics for reduction of the PQ supply system. The power quality of the system becomes very important issue due to the utilization of the power electronics devices and their application of day to day life. Power suppliers faced a number of problems for transferring the power supply from generating station to the end users and load demand centers with minimum investment or high reliability of the system. Different power quality monitoring techniques describe with their applicable solution of the issues. Custom power devices are utilized for achieving the better power quality through the mitigation techniques like UPS, UPQC, DVR, D-STATCOM and TVSS for the system. Due to the different advantages of the power quality S-TATCOM can be utilize for renewable energy system. Spinning reserve is the traditional method for improving the power quality of the system. Flow chart of the power quality of the system provide the information of the about the problem identification and evaluation of the problem of power quality in first stage. It can be divided into five parts of the problem evaluation like voltage sag, transients, flicker, voltage regulation and harmonics distortion. &nbsp; After the determination of the problem, measuring and collecting data of the problem have been taken account through the malfunction of the system.</span></p> <p><span style="font-weight: 400;">Power quality of the power system is a combination of the voltage and current quality. Voltage stability of the system is a very important issue for the power quality. System quantity have the affected by reactive power time constant of the voltage regulation with system excitation.</span></p> <p><span style="font-weight: 400;">Power qualities of the DC system have higher arrangement of the reliability which have two advantages like the poor detection of the faults and instability. Various type of equipment’s and the system have been affected through the different issues power quality of their impact. Economic burden and loss of equipment life is created on the system through the various power quality issues. These issues of the power quality have the impacts with the effect of facility like: high cost of equipment, medium cost and the low cost of the equipment</span></p> <p><span style="font-weight: 400;">Issue of the power quality have an issues on the solar power system remains in term of the low level of penetration that have the required for specific devices for serious impacts on the system. According to the different researcher PV power plant must have with stand level of pre specified with the disturbances that is related to the sag.In this paper different power quality issues of the distribution system are discussed that are related to the solar energy. A number of power quality issues, different parameters and sources of the disturbances with their effects and other parameters have been mentions. Standards of the power quality with their different issues in the energy system for monitoring techniques have been discussed with use of particular custom power devices.</span></p> Rajendra Singh Copyright (c) 2021 Udit Mamodiya 2021-09-15 2021-09-15 1 01 Rotor Modification of Switched Reluctance Motor to Improve Performance on EV Grade Application https://spast.org/techrep/article/view/2770 <p>&nbsp;Nowadays the transportation transforms to electrification by the raise of fossil fuel demands and environmental air pollution collapse. Due to this reason the electric vehicles (EVs) are introduced to reduce the fuel demands and go green. The main challenge in EVs are high cost and low mileage. These two factors are mainly depending on the selection of motor in the EV application. The current trends of EV motors material are rare earth permanent magnet comes with high cost. The low-cost material and simple manufacture Switched Reluctance Motor (SRM) is competitor in EVs motor [1]. The main drawback of SRM in EVs creates low torque density, commutation high torque ripple, radial force noise and it makes vibration [2]. This paper discusses the design of SRM with different rotor modification topology to select the suitable structure for EVs to overcome from torque ripple and density. The four different modifications in rotor round teeth, straight teeth, taper and round teeth, taper and straight teeth are analyzed using FEA simulation tool, other machine parameters are optimized. In this study, the drive duty cycle for SRM machine is selected based on the rating of power and speed. The value consider for this study are 20kW and 2750rpm and the results are discussed.</p> <p>The four rotor modification in SRM for EV application the geometry parameters are optimized. The change in rotor structure, teeth, width and compare their analysis with efficency, torque and power [3]. The electric vehicle body dynamics parameter driving conditions for 750kg at 60kmph. The drag coeffieint is 0.35, frontal area factor is 2.121m<sup>2 </sup>,rolling resistance coefficient is 0.029m and coefficient of aerodynamic resistance is 0.38 and rotational inertia factor is 1.04.</p> <p>The SRM electric vehicle total force derived using the above condition the expected torque is 70Nm. The SRM 20kW calculating outer diameter and stack length using this equation[ 4]</p> M.Deepak janaki gopalakrishnan Bharatiraja C Copyright (c) 2021 Deepak Mohanraj, janaki gopalakrishnan, Bharatiraja C 2021-10-18 2021-10-18 1 01 The DIGITAL MODERNIZATION AND NECESSITY OF ELECTROMAGNETIC COMPLIANCE: CONCERN ABOUT HUMAN WELL-BEING IN FUTURE https://spast.org/techrep/article/view/1690 <p>Digital Modernization and Digital transformation have become a predominant source of electromagnetic interference (EMI) in today’s world. The DC-to-DC Converters market is also expanding due to the emergence of digital market. DC to DC converters produce a lot of EMI and affect the performance of neighbouring sensitive systems. It is very important to comply with specifications to ensure electromagnetic compatibility (EMC) standards by prioritizing the sustainability and incorporating the social responsibilities for the human well-being. It’s really a great challenge to the design engineers to give a best solution to EMI and at the same time producing a cost effective system. During the development of a new system itself at most care need to be taken to prevent EMI. Numerous design methods, simulation tools&nbsp; are available to predict the noise level and provide feasible/reliable solutions to the problems at low cost. In-spite of that, there are some deviations in the end results in reality compare to the simulated values. This research paper focusses on the&nbsp; quick review of Electro Magnetic Interference, EMC standards as well as the comparative&nbsp; analysis of &nbsp;simulated &nbsp;and experimental EMI measurements of a DC-DC converter.</p> JANAKI G Ramya K Copyright (c) 2021 JANAKI G, Ramya K 2021-10-08 2021-10-08 1 01 A REVIEW ON VARIOUS PIEZOELECTRIC MATERIALS FOR CURRENT APPLICATIONS https://spast.org/techrep/article/view/310 <p>In general, everyone wants new technology to survive in this competitive world. In the<br>segment of instrumentation, the transducer is one of the electrical devices well suited for<br>domestic and small-scale industry applications. One of the new technologies in the<br>transducers such as piezoelectric transducer is widely used in the electrical and mechanical<br>field applications. So in this review paper, various piezoelectric materials are discussed<br>along with their physical properties and benefits. Current applications with piezoelectric<br>transducers are discussed and analyzed based on the physical properties of these<br>piezoelectric materials.</p> B Thirumala Rao Anand Copyright (c) 2021 B Thirumala Rao Anand 2021-09-14 2021-09-14 1 01 Role of Turbine Selection in Hydropower and Wind Power for sustainable living https://spast.org/techrep/article/view/422 <div class="page" title="Page 1"> <div class="layoutArea"> <div class="column"> <p>The need for renewable energy has exponentially grown in the past two decades due to the concerns of global warming and greenhouse gases, the energy generated for non-renewable and conventional sources of fossil fuels are being reduced slowly to provide the green energy sources an upper hand in the scope of sustainable living. Taking into consideration of two main renewable energy such as hydropower and wind energy, a common component in these two is the turbine and blades. This paper provides an insight about various turbines combination in the hydropower for optimal energy generation with a case study. On the other hand the role of blades in the wind energy generation.[1,2] This paper also provides a broader aspect of mathematical calculations in the field of hydropower by comparing and contrasting with the presence of a dam[4-6], followed by the mathematical modelling of wind turbine and electrical modelling of wind energy generation considering a live wind pattern.[3]</p> </div> </div> </div> Viswanathan Ganesh Ajay Krishna V.M Ajit Ram R.R Copyright (c) 2021 Viswanathan Ganesh, Ajay Krishna, Ajit Ram 2021-09-15 2021-09-15 1 01 Power Quality And Low Voltage Ride Through Capability Enhancement In Wind Energy System Using Unified Power Quality Conditioner (UPQC) https://spast.org/techrep/article/view/3388 <p>The various approaches used to improve the Low Voltage Ride Through (LVRT) capabilities of DFIG-based wind turbine systems are investigated in this study (WT). The Type-III WT machine, which is primarily based on DFIG, is connected to the grid without a digital power interface, resulting in unmanageable terminal voltage or reactive electricity output. As a consequence, novel LVRT approaches based on the deployment of additional active interface technologies were given in this work. The problem of low voltage faults is now being addressed using a variety of approaches. By analyzing LVRT approaches for DFIG-based WECS, this research attempts to discover such working ways by bridging the gap in terms of overall adaptive performance, operative complexity of controllers, and cost-effectiveness. This study suggests ways to improve LVRT's ability to rely on the relationship arrangement in three major areas based on their grid integrations. The wind turbine system is connected to a DVR, STATCOM and UPQC in this study for active and reactive power regulation throughout the fault detection procedure. Using UPQC with SRF theory offers improved reaction during faults to increase active power and maximum compensation in reactive power with synchronous reference frame and without synchronous reference frame operation presented in this paper.</p> Subash Ranjan Kabat Chinmoy Kumar Panigrahi Copyright (c) 2021 Subash Ranjan Kabat, Chinmoy Kumar Panigrahi 2021-11-09 2021-11-09 1 01 A Photovoltaic Tied Three-Phase Transformerless DC-MLI Control Switching to Accomplish the Grid Connected Solutions https://spast.org/techrep/article/view/2806 <p>Due to their superior performance over other inverter topologies, photovoltaic (PV) tied Z-source Diode-Clamped (DC) multilevel inverter (MLI) topologies are widely employed for high-power medium voltage grid linked applications. Due to its single stage power conversion, Z-source DC-MLI (ZsDCMLI) is employed in solar grid linked applications where it outperforms traditional inverters. Despite the fact that Z source inverters are accepted in grid connected technologies, a sufficient controller to meet the grid/standalone standards is required. The MLI are used in most of the power electronic industries for its better harmonics performance, lower switching stress, lower losses etc. For increasing the AC output voltage, the Z-source converter circuitry uses two identical structures: X-shaped capacitance and inductance, and an impedance network connected between the DC input source and the inverter circuit [1]. The DCMLI is a topology from the MLI family that can accommodate all of the circuit and operation features of a traditional two-level inverter. The preceding literature review gives an overview of the work that has been done on space vector PWM development and implementation. It, on the other hand, lacks a thorough understanding of Z-source MLI Space vector modulation (SVM) development and implementation. Because of the adequate voltage vector selection opportunity, the SVM is a popular modulation technique for Z-source NPC-MLIs. The control of a Z-source MLI inverter with and without modification of shoot through switching has been demonstrated in previous papers. However, no attempt is made to use a current controller (CC) to implement SVPWM, which is the most important factor for a grid-connected inverter to offer minimal harmonic distortion and good quality current [2]. The grid-connected CCs should operate using a direct control method based on the grid reference. Researchers have proposed alternative PV powered transformerless (TL) inverters for grid connected power systems in both three and single&nbsp;phases to tackle the transformer dependency issue [3]. Many single phase TL inverter topologies have been developed, with the goal of simply reducing leakage current by adding extra power switches to the main inverter circuitry. The study in three-phase networks is entirely focused on PWM and current control design algorithms [4],[5]. In terms of reducing harmonic content output waveforms and suppressing common mode voltage (CMV), Z source MLIs are a better choice for PV applications than two-level VSIs.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; In this paper a PWM method proposes for the performance enhancement of PV-tied Z-NPC-MLI grid-connected system with a unique hysteresis current control SVPWM (HSVM) technique and neutral point (NP) balancing control to achieve all of these goals. The suggested current control provides good direct current control with neutral point balancing on the inverter input side. As a result, the suggested CC ensures a high-quality current and voltage waveforms for utility grid. The HCC and SVPWM adaptations to the Z-MLI for NP balancing were described in the article. MATLAB/Simulink software is used to model and verify the proposed system. The validation of the laboratory prototype 2-kWp solar panels attached grid linked three-phase three-level Z-NPC-MLI is done using a Xilinx family SPARTAN-6 controller. The feasibility and reliability of the suggested CC for the PV tie grid linked Z- Source MLI were proven by simulation and experimental results. The CC can be used with other MLI topologies as well.</p> bharatiraja Chokkalingam c sathakumar Copyright (c) 2021 bharatiraja Chokkalingam, c sathakumar 2021-10-17 2021-10-17 1 01 THe DC-DC Bidirectional converter model interfacing two energy storage systems proposed for HEV’s https://spast.org/techrep/article/view/2843 <p><strong><em>A design of dc/dc Bidirectional converter (BDC) interfacing two energy storage systems i.e., Main (ES1), and auxiliary (ES2) and a dc-bus of various voltage levels for Hybrid Electric vehicle is proposed in this paper. In this system we have power flow control in two directions, both step-up and step-down i.e., Low voltage powering mode and High voltage regenerative mode. Furthermore, this model can switch from one mode to another on multiple bases i.e., Low-voltage accelerating to regenerative and buck/boost mode. To understand the methodology involved in&nbsp; this proposed converter, the three different modes of power transfer, their circuits, working, and close loop control along with simulation results for a one-kW system is discussed. </em></strong></p> Mohammed Ekkram Uddin Mohammed Lateef Uddin Copyright (c) 2021 Mohammed Ekkram Uddin Mohammed Lateef Uddin 2021-10-18 2021-10-18 1 01 Prediction and validation of overall energy consumption of Sustainable buildings with machine learning techniques https://spast.org/techrep/article/view/1711 <p>Electricity consumption plays a vital role in any building's energy consumption. One of the main features of sustainable building is to reduce the energy consumption to the lowest level without comprising the comforts, and at the same time, it should be cheaper to implement. It is essential to forecast the load requirement to tap the onsite renewable energy sources economically.</p> <p>Predicting the electrical load usage is an essential element to validate sustainable building design. The building has to suffice with onsite renewable energy sources, and it should meet the entire load of the building with onsite renewable energy generation.</p> <p>The conventional algorithms, approaches are too time-consuming and complex to predict the energy consumption, its savings, and finally to compare with onsite renewable energy generation.&nbsp;</p> <p>In this research paper, the data analytics framework supported with Python library functions and subsequent machine learning algorithms can efficiently address these issues.&nbsp;</p> G R K D SATYA PRASAD GOLLAKOTA Copyright (c) 2021 G R K D SATYA PRASAD GOLLAKOTA 2021-10-08 2021-10-08 1 01 The Study on Refined Coconut Oil as Transformer Liquid Insulation https://spast.org/techrep/article/view/2915 <p>Transformer is a vital equipment in power system. Liquid insulation is most commonly used in high voltage systems such as power transformer where it provides electrical insulation, extinguishes arcing and acts as a coolant agent to prevent the transformer from overheating. Mineral oil is commonly used as the transformer oil. Mineral oil has negative impact on the environment, contaminating the soil and water, whenever there is an accidental transformers fires, explosions or tank rupture. To combat these causes, alter- native environment friendly and oil with similar properties and characteristics as mineral is needs to be used as liquid insulation[1]</p> <p>Refined coconut oil is commonly available and highly reliable and it’s basic properties such as flash point, pour point, viscosity, specific gravity, etc. Before oil use in transformer, oil has been pre-process using Nitrogen bubbling method.</p> <p>Actual transformer oil properties and characteristics are simulated through conduction of accelerated ageing on pure coconut oil samples. Nitrogen bubbling is used to remove dissolved oxygen content in coconut oil. Effects of different concentrations of DBPC and passivators had been explored as well. To understand the behavior of oil with these chemical compounds, conduction of Breakdown voltage and Leakage current, DC Resistivity, Dielectric Constant, Capacitance and Tan-Delta tests were carried out in High Voltage Lab. The migration of the Copper Sulphide (Cu2S) into the solid insulation was also demonstrated to show the eventual destruction of both solid and liquid insulation properties through a simulation done on a Finite Element Modelling (FEM) method in Ansys software[2-4].</p> <p>From the studies conducted, it was concluded that: DBPC is needed in preventing sludge formation. Passivators had shown to play a crucial role by prolonging the life of transformer oil.&nbsp; It was discovered that for samples with passivators – as the ageing period increased the di-electric strength of the oil reduced and from this observation it was concluded that passivators had degraded over a period of time. It was also found that 500 ppm of Igramet- 39 had the most optimum effect of prolonging the life of the liquid insulation</p> suresha C Copyright (c) 2021 suresha C 2021-10-22 2021-10-22 1 01 Model Predictive Control of PMSM Motor Drive for Electric Vehicle Applications with Space Vector Modulation https://spast.org/techrep/article/view/1509 <p>Electric Vehicle (EV) is the recent technology which is becoming more commercialized around the world. Therefore, research around EV in the domain of drives, motors, charging infrastructure, etc. is increasing gradually. The motors which are preferred for EV application is Brushless DC (BLDC) motor, Induction Motor and Permanent Magnet Synchronous Motor (PMSM). BLDC motor is applicable for low power applications, thus only 2-wheelers and 3-wheelers can be driven. For high power application, Induction motor and PMSM are available, in which, Induction motor has low efficiency and high core losses. Therefore, PMSM is preferred for EV applications, as it gives high power, high torque density, high efficiency and better thermal management capacity. In recent years, multi-phase motor drives have gained more attraction for its reduced losses, lower Common Mode Voltage (CMV) and better efficiency over 3-phase motor drives. Among the multi-phase motor drives, the five 5-phase motor drives are selected for their robust control. In this paper, Model Predictive Control technique with Space Vector Modulation for PMSM motor drive is done.</p> Vinoth Jayakumar Bharatiraja Chokkalingam Copyright (c) 2021 Vinoth Jayakumar, Bharatiraja Chokkalingam 2021-10-07 2021-10-07 1 01 Maximum Power Point Tracking of a Standalone Photovoltaic System Consisting of a Series Connected Supercapacitor https://spast.org/techrep/article/view/1242 <p>Standalone photovoltaic (PV) systems are used in remote areas where the utility grid is not accessible. PV panels of a standalone PV system are connected with a charge controller as the first power conversion stage. The efficiency of the power stage of charge controllers is around 90% [1]. Researchers worldwide are trying to increase the power stage efficiency while limited attention is given to finding alternative methods. Reference [2] has presented a possible approach for enhancing the efficiency of a standalone PV system by an additional 9% by connecting a supercapacitor (SC) bank in series configuration with the PV panel and charge controller. This approach utilises a concept called SC assisted loss circumvention theory to develop the proposed system. This theory describes the RC circuit's efficiency enhancement, consisting of an SC bank and a useful load [3]. However, the feasibility of maximum power point tracking (MPPT) for this system is yet to be validated. With the variation of incident sunlight and temperature, the power generation of the PV panels varies. With these variations, the maximum power point (MPP) of typical standalone PV systems is tracked by varying the duty ratio of the built-in DC-DC converter's PWM signal in the charge controller by executing MPPT algorithms. A summary of existing MPPT algorithms can be found in [4]. This study presents a comparative study for the adaptation of MPPT for standalone PV systems consisting of a series-connected SC bank with PV panel and buck converter. The buck converter is used as the impedance matching network and is connected to a battery bank and a load as per the typical standalone PV systems. A Static irradiance profile was emulated to observe the static MPPT efficiency. Slow ramp, fast ramp, and ramp and drop irradiance profiles were emulated to observe the dynamic MPPT efficiency of the proposed system. From the results, it was shown that the typical MPPT can be adapted to the proposed type of standalone PV systems as compared with typical systems. Therefore, we hope that these results could be beneficial in developing highly efficient MPPT standalone PV systems soon.</p> Kasun Piyumal Aruna Ranaweera Sudath Kalingamudali Nihal Kularatna Copyright (c) 2021 Kasun Piyumal, Aruna Ranaweera, Sudath Kalingamudali, Nihal Kularatna 2021-09-30 2021-09-30 1 01 Migrating Data to NOSQL Databases and Improving Data Quality for Big Data Analytics https://spast.org/techrep/article/view/2197 <p><span class="fontstyle0">Today, in the computer science world, data has become an essential hub for information processing in general.<br>these data continue to progress in a progressive and exponential way, especially in storage and its technologies. The term Big Data as we use it for mass volumes of data, offers important techniques for processing, analyzing and proposing useful information for decision making. NOSQL databases become a modern and indispensable technology to use, to provide scalability to support large data; this is why there is always this challenge for organizations to transform their existing databases to NOSQL databases by considering the heterogeneity and complexity of relational data. In this paper, we propose an approach for the migration of a relational database to another NOSQL; this method has two phases, the first is to transform the relational database to a NOSQL database, and the second is to enhance and improve the quality of the data with cleanup processes to provide and prepare them for big data analytics systems</span> </p> Abdelhak ERRAJI Copyright (c) 2021 Abdelhak ERRAJI 2021-10-07 2021-10-07 1 01 Pore-Scale Modelling of Metal Foam Heat Exchanger https://spast.org/techrep/article/view/1185 <p class="Abstract"><span lang="EN-US">Heat exchangers have been essential in thermal energy systems. Increasing the heat transfer performance of heat exchangers has been the focus in thermal engineering field. This study aims to investigate transport processes in metal foam heat exchangers by adopting 3D pore-scale model which is expected to provide better accuracy and details on the transport processes in metal foam heat exchanger. The numerical study done has been initiated with the model development, followed by numerical implementation and finally numerical investigation. The numerical investigation reaffirms past studies that the presence of metal foam does bring enhancement to the heat transfer. However, it comes with the sacrifice on the huge change of pressure of the fluid. The adoption of pore-scale model revealed details of transport processes inside metal foam heat exchangers.</span></p> Adam Reduan Chin Jundika Candra Kurnia Agus Pulung Sasmito Copyright (c) 2021 Adam Reduan Chin, Jundika Candra Kurnia, Agus Pulung Sasmito 2021-09-24 2021-09-24 1 01 Improvement in the performance of perovskite solar cells by reducing defect density with antisolvent treatment https://spast.org/techrep/article/view/2015 <p>Methylammonium lead (II) mixed halides (CH3NH3PbI3-xClx) have emerged as promising and efficient photoactive material owing to its excellent light absorption, low exciton binding energy, high carrier mobility and facile solution processability. Generally, vapour-assisted and two-step sequential deposition methods have been utilized for perovskite film formation for making efficient solar cells. The film qualities of perovskite photoactive layers like crystallinity, defect density, homogeneity, surface coverage, optical absorption etc. plays crucial role in the photovoltaic performance. Perovskite films deposited by conventional spin-coating methods generally have some pin-holes and randomly oriented fine grains with a poor substrate coverage. <br>In this work, we have investigated the influence of chlorobenzene antisolvent treatment on perovskite film formation in inverted planar perovskite solar cells. Herein, we report the formation of smooth, pin-hole free flat homogeneous perovskite film by one-step antisolvent induced crystallisation method for the device configuration of ITO/PEDOT:PSS/ CH3NH3PbI3 xClx/PC71BM/Al.. The process involves spin-coating of perovskite precursor followed by addition of antisolvent liquid (chlorobenzene) in the mid of the spin-coating process. This antisolvent treatment process has shown an effective way to improve the morphology of the perovskite film as well as photovoltaic performance of the PSCs. The significant superior photovoltaic performance has been obtained with antisolvent treated PSCs having average PCE ~ 11.5% as compared to conventional spin-coated planar PSCs with an average PCE ~ 8% as shown in Fig 1. <br>In order to investigate this enhanced photovoltaic performance in antisolvent assisted PSCs, systematic investigations using optical absorption, IPCE, electroluminescence (EL), electrochemical impedance spectroscopy (EIS), capacitance-voltage (C-V), XRD, and scanning electron microscopy (SEM) have been carried out. <br>An enhanced absorption in antisolvent treated films in 400-650 nm wavelength range was observed which was also supported by IPCE measurements. We studied the electroluminescence (EL) emission spectrum for distinguishing the recombination losses. Conventional PSCs showed an increased loss due to non-radiative recombination as compared to antisolvent treated PSCs. This increased recombination loss was confirmed with electrochemical impedance spectroscopy (EIS) and Mott-Schottky (MS) analysis. Capacitance-voltage (C-V) measurement using MS plot has been used for distinguishing the effects taking place in bulk of the active layer and those occurring at the interface of perovskite/ETL or HTL [1,2] . We found lower built-in potential (Vbi) of 0.77 V and higher defect density (N) of 24.6 x 1016 cm-3 for conventional planar PSCs as compared to antisolvent treated PSCs with Vbi ~ 1.135 V and N ~ 24.6 x 1016 cm-3 [3]. The higher defects exerts extra potential barrier and hinder the charge carrier’s extraction. It also induce trap-assisted recombination and reflects as lower Voc and PCE as in case of conventional PSCs. The lower trap density and higher Vbi results in lower non-radiative recombination which is beneficial to raise both the Voc and PCE for antisolvent PSCs. In EIS studies, we have found two signals in the form of arcs in Nyquist plot and in the form of peak in bode plot at 104-105 Hz and 1 Hz respectively. We found a good agreement between ideality factor (nid) determined by two different methods viz. Sun-Voc (extracted from J-V curves) and Sun-RHF (extracted from EIS). Ideality factor of 1.64 and 2.28 has found for antisolvent treated and conventional PSCs [4]. The higher nid confirms the increased recombination loss in conventional PSC. <br><br>Fig. 1. Current density−voltage curves of devices fabricated with conventional and antisolvent treated PSCs. Inset shows the schematic diagram of the planar inverted perovskite device.</p> <p>The XRD measurements on the films revealed that antisolvent treatment causes improved crystallinity of perovskite structure and preferred crystal growth in (110) direction. SEM studies also confirmed the formation of smooth and pin-hole free perovskite film formation with antisolvent treated perovskite film. It is therefore concluded that the enhanced photovoltaic performance in antisolvent-assisted PSCs is attributed to smooth pin-hole free perovskite film morphology having lower defect density and recombination losses.</p> Deeksha Gupta Copyright (c) 2021 Deeksha Gupta 2021-10-09 2021-10-09 1 01 Optical Analysis of a Flat Plate External Compound Parabolic Concentrator for Photovoltaics Thermal Applications https://spast.org/techrep/article/view/625 <p>The world-facing growth of carbon emissions and energy demand became a challenge. Solar thermal technologies are a viable renewable energy solution to meet the heat demand of residential and industrial applications [1]. The most promising solar thermal technologies are concentrated solar power (CSP) and solar water heating. These technologies had rapid growth in the past decades. In India, 50% of total energy demand is consumed by the industry sectors and it is projected to grow massively. India receives the daily average solar irradiation of 5000 trillion KWh and 2300 to 3200 sunshine hours per year [2]. Many processing industries require a temperature below 400°C. So, the industrial heating demand can be classified based on the temperature range are as follows: low (&gt;100°C), medium (100 to 250°), high (&lt;250°C) [3], [4]. The low-temperature collector is well-developed technology, but the medium temperature range collectors are not much developed. Even though many solar technologies are available but it intermittence of solar radiation and economic benefits are not viable. Unlike thermal systems, photovoltaics have become more popular and feasible to use in industries. In recent years the development of combined electricity and heat generation receiving more attention and it is called concentrator photovoltaic thermal (CPVT) applications [5]. Many small and medium scale industries are not having enough space to install solar technologies [6]. But, the XCPC is more suitable for rooftop applications and is not required any tracking system [7]. The present study aims at evaluating the optical performance of a flat plate absorber with an external compound parabolic concentrator (XCPC) used for medium temperature applications [8]. The optical performance of the XCPC collector is mainly affected by the geometrical characteristics, those are truncation residual ratio (Ct), the reflectivity of the reflector and half acceptance angle (θa). The whole simulation has performed using the Tonatiuh ray-tracing software, which is open-source software and it used the Monte Carlo ray-tracing techniques[9].</p> <p><br>Initially, the simulation model has validated with existing literature results [10]. Once established with the validation, the investigation is carried out by investigating the effect of truncation residual ratio (Ct), reflectivity and half acceptance angle (θa) of the XCPC collector on the optical performance of the collector. Based on the simulation results, the power production per aperture area, optical efficiency and incidence angle modifier were calculated. It is found from the results that when truncation residual ratio (Ct = 1), the optical performance performs better under sun incidence angle (0-20°) beyond the incidence angle 20° it performs worse. This happens because, when Ct is decreasing the amount of sun light-receiving is increased and power per aperture area is low at a smaller incidence angle vice versa; it is depicted in Fig. 1 (half acceptance angle is 20°). The optical efficiency varies concerning the quality of the reflector, mainly under a low incidence angle which is equal to the half acceptance angle of the XCPC. For different half acceptance angles (θa), power production per aperture area is constant up to the incidence angle lower than the acceptance angle (θa). Fig. 2 shows the optical efficiency of XCPC for different acceptance angles. Where (θa = 30°) having a concentration ratio of 2, it has the maximum optical efficiency comparative to another acceptance angle. The results of the study help to identify the optimum geometrical parameters for designing the XCPC-CPVT applications.</p> Mathiyazhagan Shanmugam Lakshmi Sirisha Maganti Copyright (c) 2021 Mathiyazhagan, Lakshmi Sirisha 2021-09-16 2021-09-16 1 01 Effects of Sulfur induced in TiO2 for high-performance on thermoelectric device https://spast.org/techrep/article/view/2125 <p>The TiO<sub>2</sub> materials provides the possibility of allowing sulfurizing by wet-ball milling followed by annealing and pressure sintered at 200° C for 10 min under uniaxial pressure of 400 MPa. The addition of small amount of sulfur powder in set during annealing period to prevents sulfur deficiency in the sintered compact, resulting in the formation of near-stoichiometric composition. Here, we report for the first time a novel wet-milling assisted-sintering method to achieve high-performance two-dimensional (2D) semi-metallic sulfur doped TiO<sub>2</sub> platelets. Ball milled processed 2D materials provides the possibility of allowing these materials to be incorporated into scale up device fabrication. The formation of 2D nanoplatelets functionalized with Ti and S was confirmed through X-ray diffraction, Field-emission scanning electron microscopy, and energy dispersive spectroscopy. The thermoelectric properties were measured in the temperature range of 25 °C to 100° C and it is showing promising candidates for highest ZT 0.35 at 100° C.</p> Shalini M Pandiyarasan Veluswamy shankar H Copyright (c) 2021 Shalini M, Pandiyarasan Veluswamy, shankar H 2021-10-08 2021-10-08 1 01 MxFe[Fe(CN)6] for room temperature rechargeable alkali metal ion battery https://spast.org/techrep/article/view/697 <p>The increased challenges created by the limitations of oil based resources plays a crucial role in developing new technologies which is green, sustainable and safe. Lithium ion battery plays a vital role in a transition from fossil fuels to renewable energy system. However, large scale energy storage systems (EES) are a main factor for a smooth integration of renewable energy to grid. A smart reliable alternative or a support system is required for the current lithium ion battery technology due to the less resource and high cost of the material. The wide resources and similar chemistry of sodium makes it an ideal alternative for this technology. Nevertheless, the larger ionic radii of sodium ion compared to lithium ion leads to poor kinetics [1]. Among various cathode materials proposed, Fe[Fe(CN)<sub>6</sub>] Prussian blue (PB) and its analogues (PBAs) are considered to be a favorable cathode material because of its properties like robust structure which could undergo several interstitial modification and substitution without affecting the structure. This open frame work enables good diffusion kinetics even for larger cations. Nonetheless, the challenges like high cycle life, less reversible capacity as well as the coordinated water molecule also leads to a less utilization of theoretical capacity [2-4] limiting the PBAs being commercialized.</p> <p>In the current work, we report a simple, scalable and sustainable approach using PBAs as cathode for two prominent metal ion (Li and Na) battery applications. As iron and sodium being abundant, the major focus of this work was to develop a sodium cathode even though Li-ion battery applications have also been reported. Herein, we have synthesized iron hexacyanno ferrate through a single iron source by a precipitation process [5] and further the product has been lithiated and sodiated at a lower temperature of 80 °C at a time duration of less than 15 minutes. Apart from the productive preparation part several characterizations have been done. The phase purity of all the samples including bare Fe[Fe(CN)<sub>6</sub>], sodiated Na<sub>x</sub>Fe[Fe(CN)<sub>6</sub>]&nbsp; and Li<sub>x</sub>Fe[Fe(CN)<sub>6</sub>] lithiated has been done. The morphology has been imaged under a FESEM which attributes the lithiation/sodiation didn’t invoke any change in structural as well as morphology. Further the surface chemical analysis has also been conducted and the electrochemical evaluation has been widely studied through galvanostatic rate performance, cycling and subsequently using impedance spectroscopy. Even though the lithiation efficiency was lesser, almost complete sodiation of Fe[Fe(CN)<sub>6</sub>] has been observed, which has been realized through the quantified first charge-discharge capacities. A prolonged performance cycles at 100 mA/g current density has been shown for lithium and sodium ion batteries. A retention rate of 92% and 69% has been observed for both Li<sub>x</sub>Fe[Fe(CN)<sub>6</sub>] and Na<sub>x</sub>Fe[Fe(CN)<sub>6</sub>] respectively. Such a lithiated and sodiated Fe[Fe(CN)<sub>6</sub>] under a solvent medium in atmospheric condition has not been reported for iron hexacyanoferrates to the best of our knowledge. It may be noted a complete sodiation process and not complete lithiation, further detailed investigations are required to understand the reasons for the same. In summary, this study gives new insights into a cost effective, rapid and low temperature process to develop a sodium ion containing Fe[Fe(CN)<sub>6</sub>] battery applications.</p> Dona Susan Baji Copyright (c) 2021 Dona Susan Baji 2021-09-16 2021-09-16 1 01 Evaluating Energy Storage Systems for Renewable Energy Integrated Urban Community Microgrid Systems https://spast.org/techrep/article/view/2161 <p>Energy storage systems play an important role in the ever-increasing reliance on renewable energy technologies, especially in deregulated energy grid systems. There are many promising stationary energy storage technologies currently in the market or in development; however, not all these technologies can be used in an urban community microgrid system (UCMS) primarily because of constraints, such as costs and land requirements. A UCMS is characterised as a completely off-grid microgrid systems installed in a city environment connected with its residential community through physical placement and owned by said community. This research explores all available, and developing, energy storage technologies by reviewing and analysing academic and industrial publications and then validating the data by interviewing industrial experts for a real-world perspective on the suitability of these technologies for UCMSs. Technologies are evaluated by under five main themes: technological capability, market readiness, LCOS (levelised cost of storage), location of installation (in homes, communal areas, or energy farms located outside cities/community system), and environmental impact. Based on these themes, and their parameters, an up-to-date summary of suitability for UCMSs is established. With the evaluation of which, it is found that a combined energy system, with Lithium-ion batteries installed in communal areas for electricity and hot-water energy storage tanks installed in residential dwellings for heat energy, is currently the most suitable storage system for a UCMS in the United Kingdom (UK).</p> Akash Kapur Copyright (c) 2021 Akash Kapur 2021-10-08 2021-10-08 1 01 Role of pH of electrolytic pH on the performance of nanostructured ZnO thin films in photoelectrochemical water splitting https://spast.org/techrep/article/view/265 <p>World power consumption has reached 15 terawatts (TW) and it is all set to amplify in the future. To reduce the energy crisis renewable energy can play a significant role. Solar energy induced hydrogen production via photoelectrochemical path is the most encouraging pathway to find alternate source of energy [1-3].</p> <p>The present study is focused on nanostructured thin films of zinc oxide (ZnO) deposited on ITO glass substrate using sol-gel spin coating method. Samples were characterized using X-ray diffractometry (XRD), Field Emission Scanning electron microscopy (SEM) and UV-Vis spectrometry etc. The pH of aqueous solution of NaOH &amp; KOH electrolyte was varied from 9-13 pH and its influence was studied on the performance of photoelectrochemical (PEC) water splitting for hydrogen production. The photocurrent-voltage (J-V) characteristic of ZnO electrodes were studied &amp; analyzed for all variables. Maximum photocurrent of 13.8 mAcm<sup>-2</sup> at 1.23V/RHE was obtained at pH 13 of NaOH electrolyte. Detailed results would be discussed</p> Neeraj Kumar Biswas Anuradha Verma Vibha Rani Satsangi Rohit Shrivastav Sahab Dass Copyright (c) 2021 Neeraj Kumar Biswas, Anuradha Verma, Vibha Rani Satsangi, Rohit Shrivastav, Sahab Dass 2021-09-11 2021-09-11 1 01 Role of perovskite-type oxides in energy harvesting applications https://spast.org/techrep/article/view/302 <p>Perovskite type oxide (PTO) is an extensively studied material over the past decade. There are differences in the ionic radii and electronegativity of the perovskite structure that results in distortions due to the creation of oxygen or cationic vacancies, or changes in the bonding angles of cations and oxygen. Metal at the B-site of ABO<sub>3</sub>-type perovskites could transfer its s-electrons to the oxygen ions while the remaining strongly correlated d-electrons greatly effects the electronic and magnetic properties like colossal magnetoresistance, multiferroicity and superconductivity [1]. Additionaly, many perovskites have the capability of holding versatile forms of order in their charge, spin and orbital states. The presence of two perovskites having different electronic orders at the interface results in a more complex phenomena like a two-dimensional electron gas, topological insulators, and anomalous quantum Hall effect. The technical advancement in the atomic-scale synthesis of oxide heterostructures made it possible to fabricate atomically abrupt artificial superlattices with novel states at the interfaces. The defects and order–disorder crystalline structures existing in the perovskite family, lead to a rich spectrum of functional properties, like ferroelectricity, piezoelectricity, catalytic activity, and non-stoichiometry related magnetism phenomena [2]. In reality, the real perovskite oxides tend to show complex chemical compositions and crystalline structures.They are also known to exhibit excellent metallic, superconducting, supermagnetic, dielectric, optoelectronic, semiconducting, and insulating properties [3]. PTOs have established themselves as well-known structures in solid-state physics due to their structure, geometry, and properties that can be flexibly tailored. The PTOs have recently drawn enormous attention as a potential platform for upcoming energy harvesting and storage technologies. Due to their fascinating properties, PTOs have attracted the attention of researchers in energy harvesting applications, including solar cells, supercapacitors, solid oxide fuel cells (SOFCs), and lithium-based batteries (LBs). There has been significant achievements in the synthesis perovskites and their device fabrication. PTOs energy harvesting properties is due to their strong ferroelectric and ferromagnetic behaviour [4]. Perovskites have also established themselves as a solar energy harvesting material in recent years owing to their desirable photovoltaic properties [5]. Doping or fabricating multilayered structures is an effective method to increase the efficiency of traditional solar cells, which can also be introduced in ferroelectric perovskite solar cells to achieve a more complete absorption of the solar spectrum. The potential strategies for a more effective use of these materials can involve multiple energy conversion mechanisms through a single device or employing materials where a solar or thermal input provides multiple electrical outputs to enhance the overall energy harvesting capability. This paper reviews the contribution of perovskite-based oxides in these applications. It also overviews the developments and limitations in their existing technology. In this context, the future scope of these materials has been investigated to enhance the performance parameters like power conversion efficiency, specific capacity, cycle life, and energy densities. This study will not only help in selecting an appropriate material from the existing pool of perovskite materials but will also provide an outlook and assistance to researchers in developing new material systems.</p> BHAVYA PADHA Copyright (c) 2021 BHAVYA PADHA 2021-09-20 2021-09-20 1 01 Investigation of quaternary Nickel Cobalt Tungstate and its carbonaceous materials as an alternative counter electrodes for Dye Sensitized Solar Cells (DSSCs) https://spast.org/techrep/article/view/2760 <p>Dye Sensitized solar cells (DSSCs) are the third generation solar cells received great attention due to its low cost, environment friendliness, and ease fabrication relative to former silicon solar cells<sup>1</sup>. Counter electrodes are one of the major components in DSSC such as photoanode, electrolyte and dye. The counter electrode should possess good electrocatalytic activity, high conductivity, high reflectivity, corrosive resistance and high stability at the electrode / electrolyte interface. Platinum based counter electrodes are still a benchmark counter electrode for DSSC due to its excellent properties such as high electrochemical activity, stability and reflectivity. However due to its cost, research groups were started focusing developing alternative counter electrodes materials such as Transition metal oxides, nitrides, sulfides, telluride and carbon based materials due to its cost, ease preparation. Metal oxides and sulfides mixed with various carbonaceous materials such as carbon Black, Mesoporous carbon, reduce graphene oxide, few layer graphene, and bio mass derived carbons induces a synergetic effect leads to enhanced electrocatalytic and conductivity at the electrode/electrolyte interface. Many researchers investigated vast metal compounds in binary, ternary, and quaternary and its carbon composites with the aim to find an alternative counter electrode material for DSSCs.</p> <p>Among many binary compounds Tungsten trioxide (WO<sub>3</sub>) showed relatively good performance among the binary compounds due to its similar structural properties like platinum<sup>2</sup>. On the other hand, Bio mass derived carbons such as Activated charcoals, carbon from aloe peel, cellulose filter paper, rice husk and corn stalk becoming promising alternative electrode materials<sup>3</sup>. These bio mass derived carbons were hydrothermally treated followed by a KOH activation leads to micro and macro porous carbon materials leads to ultimate redox properties. Metal oxide materials such as ternary Nickel and zinc tungstates were recently reported with bio mass derived carbon extracted from Aloe Vera leaf. Out of various ternary tungstates FeWO<sub>4</sub>, MnWO<sub>4</sub>, CuWO<sub>4</sub> CoWO<sub>4 </sub>and its bio mass derived carbon, Nickel and zinc tungstate NiWO<sub>4</sub>/Bio mass carbon<sup>4</sup> and ZnWO<sub>4</sub>/Bio mass carbon resulted<sup>5</sup> in enhanced conversion efficiency due to the synergetic effect. In the present work, we prepared a quaternary Nickel Cobalt tungstate and its carbonaceous composites such as reduced graphene oxide (rGO) and Activated charcoal (AC) via facile hydrothermal method. The structural and surface characteristics were studied using X-Ray Diffraction, Scanning Electron Microscopy and Raman spectroscopy. The XRD spectra confirms the prepared materials are highly crystalline nature and the presence of carbon materials has been confirmed with Raman spectroscopy. The redox properties and catalytic behaviour have been investigated using cyclic voltammetry (CV) to study its interactions at the electrode /electrolyte interface. The cyclic stability studies has been carried out to study the electrode stability at the interface. Electrochemical impedance spectroscopy (EIS) and Tafel Polarization curves were carried out on the symmetric dummy cell, fabricated using two identical NiCoWO<sub>4 </sub>/ Carbonaceous material with the liquid electrolyte injected between the two electrodes, to study its charge carrier dynamics such as diffusion, Charge transfer resistance and sheet resistance at the electrode /electrolyte interface&nbsp; in order to find the suitability of the prepared materials as an alternative counter electrode materials for DSSCs.</p> Mathan Kumar P RajagopalPeri Mohanaselvi T Muthuraaman. B Copyright (c) 2021 Mathan Kumar P, RajagopalPeri, Mohanaselvi T, Muthuraaman. B 2021-10-21 2021-10-21 1 01 Ni0.85Se/MoSe2 Interfacial Structure: An Efficient Electrocatalyst for Alkaline Hydrogen Evolution Reaction https://spast.org/techrep/article/view/640 <p>Catalyzing hydrogen evolution reaction in alkali media is challenging owing to the sluggish kinetics, originated from the water dissociation process. In this context, synergistic coupling between Ni/Co-based materials with transition metal dichalcogenides<br>(TMDs) often accelerates the alkaline hydrogen evolution reaction (HER). Significant interaction between the two components and active-site density are the keys for achieving a promising catalytic activity. This report emphasizes a two-step selenization approach to prepare a Ni0.85Se/MoSe2 interfacial structure with abundant active sites. Initially, Ni0.75Se nanoparticles were prepared using the solvothermal method and subsequently employed them as a support for the growth of MoSe2 under hydrothermal conditions. This resulted in the formation of a Ni0.85Se/MoSe2 interfacial structure. The results of physical<br>characterization techniques confirm the significant interaction between Ni0.85Se and MoSe2. The interfacial structures showed a superior HER activity in alkali media compared to the individual components; especially, Ni0.85Se/MoSe2 (20) delivers a current density of 10 mA cm−2 at an overpotential of 108 mV. The improved HER activity of the interfacial structure is attributed to the (i) efficient water dissociation process over the Ni0.85Se promoter and (ii) exposure of more catalytic active sites (edges) of MoSe2. In addition, as-prepared Ni0.75Se exhibits a better oxygen evolution reaction (OER) activity by delivering a current density of 10 mA cm−2 at an overpotential of 340 mV. Furthermore, overall water splitting has been demonstrated by constructing an electrolyzer using Ni0.85Se/MoSe2 (20) and Ni0.75Se as a cathode and anode, respectively. The electrolyzer delivers a current density of 10 mA cm−2 at a cell potential of 1.7 V. The longterm stability experiment and the post catalytic characterization reveals the high robustness of the Ni0.85Se/MoSe2 interfacial structure.</p> HARISH REDDY INTA Copyright (c) 2021 HARISH REDDY INTA 2021-09-19 2021-09-19 1 01 Self-reporting molecularly imprinted polymer-based Electrochemical sensors for structurally similar analytes https://spast.org/techrep/article/view/3012 <p>Molecularly imprinted polymers (MIPs) are the potential replacement for the natural receptors because of its good stability, molecular recognition property and low cost. MIPs ae synthesized by polymerizing the functional monomer in presence of template molecule and subsequently creating the molecular cavity by removing the template from the three-dimensional polymer structure. MIP’s are otherwise called as artificial antibodies and plastibodies. In various detection platforms such as optical, piezoelectric, thermal, acoustic and calorimetric, sensor devices can use MIP’s as molecular recognition element. Biomarkers are selectively recognized using natural receptors such as antibodies, which are expensive to produce and that cannot withstand harsh environment conditions. Some biomarkers do not have any natural receptors which makes their detection protocol difficult. Furthermore, it is difficult to regenerate the binding sites of natural receptors for repeated measurements as the regeneration process might affect the binding affinity of biological receptors. In order to produce synthetic receptors, MIP’s and aptamers design are emerging as innovative methods in recent days. Among MIPs and aptamers, synthesis of aptamer involves some sophisticated method called SELEX and it need more technical assistance. But synthesis of MIP is easy and that can be customized to industrial scale. In electrochemical sensors, binding of analyte is measured through the faradaic current. Analytes that can be detected through electrochemical sensors are classified into electro-active and non-electro active analyte. In case of electro active molecules, analyte binding is measured through the faradaic current of analyte itself. In case of non-electro active analyte, binding of analyte is measured through the faradaic current of soluble redox markers such as ferri/ferro solution. But this soluble redox marker is etching the electrode surface and affect sensors reliability [1]. &nbsp;So, labeling of redox active moieties on electrode surface is better method to measure the non-electro active biomarkers. MIPs also face similar issues when used for measuring non-electroactive target molecule. Here, electro active molecular imprinted polymers (e-MIP) are come to play it role as a binding element as well as measuring element to detect the non-electroactive analytes selectively [2]. Electrochemical copolymerization of electro-active monomer and functional monomer in presence of template molecule and subsequent template removal step can create e-MIP’s. To demonstrate our concept, we used steroid hormone cortisol known for its stress related behavior as a model analyte and template. Absence of electro activity of cortisol restricts its direct detection in aqueous media by an electrochemical method. So, e-MIP’s can detect and measure cortisol selectively and quantitatively. It is first time to detect structurally similar steroid molecule selectively by e-MIPs. By making portable electrochemical sensor device for detecting structurally similar steroids through e-MIP, one can create a sensor device for monitoring hormone imbalance related health condition immediately. In this method, we created a versatile analyte sensing platform which can be tuned for detecting other biomarkers by changing template molecule. Stable redox active group incorporated molecular recognition element synthesized through this method can be synthesized in bulk which provides cost effective detection method with minor technical assistance. Unlike antibody production, creating MIPs is animal free method and involves only polymer matrix and thus the protocol involves MIP sensor can be called as “plastic antibody for health care diagnosis”. Integrating computational methods can be used to find suitable functional monomer for different analyte (library creation). Suitable reversible redox system can also be integrated to perform large scale commercial production. MIPs can also be regenerated for frequent monitoring. Thus MIPs are alternate tools for constructing reusable self-reporting, animal free antibodies based low energy sensors for non-electro active analytes.</p> <p><img src="https://spast.org/public/site/images/editorchief/mceclip0.png"></p> Vignesh Magudeeswaran Jayasudha Velayutham Sriraja Subhasri Paramasivam Gopi K Siva A Mariappan Pandiaraj Manickam Copyright (c) 2021 Vignesh Magudeeswaran, Jayasudha Velayutham, Sriraja Subhasri Paramasivam, Gopi K, Siva A Mariappan, Pandiaraj Manickam 2021-11-03 2021-11-03 1 01 Electrocatalytic Hydrogen Evolution using Ionic Liquid Tagged Cobalt Terpyridine Complex as Precatalyst https://spast.org/techrep/article/view/3046 <p>Concern over the global energy demand, rising of post-oil economy, climate change induced by greenhouse gases and environmental pollution upon the burning of fossil fuels have prompted the development of alternative renewable and sustainable energy sources [1]. A key challenge confronted by modern society is the advancement of high potential renewable energy source, with minimal environmental footprint. Hydrogen has gained unique attention as the most favourable fuel for the future. If the molecular hydrogen could be produced from a non-carbon source, it would be a clean fuel for future use in sustainable energy storage and transport [2]. Hydrogen is a valuable commodity that can be predominately produced via water electrolysis. Hence, the hydrogen evolution reaction (HER) plays a substantial role in the betterment of a sustainable energy economy. Electrocatalytic hydrogen evolution from water splitting emphasizes one of the economically and environmentally useful processes for the generation of clean fuels for sustainable development [3]. Thus, wide ranges of electrocatalysts are continuously being explored for hydrogen production in high purity and large quantities through water splitting.</p> <p>Nature provides molecular metal complex catalysts in the form of hydrogenases with active catalytic sites, which employ earth-abundant iron and nickel metal centers. They participate reversibly to interconvert protons to hydrogen at low thermodynamic potentials with extremely high efficiencies and activities. Impressed with the activity of hydrogenases, scientists are striving to design molecular complex based catalysts for replacing or mimicking the enzyme activities. Transition-metal complexes have a high degree of sophistication, and they store electrons through numerous redox states and are therefore admirable candidates to efficiently catalyse electrochemical water splitting reactions [4]. Several metal complexes have been employed as a catalyst for electrocatalytic hydrogen production. However, metal complexes based electrocatalysts face significant challenges and limiting factors, as many of them are soluble only in organic solvents, exhibit inadequate long term stability during the electrolysis and possess low density metal active sites. On the other hand, noble metals like platinum have shown high efficiency, but they are relatively expensive and less abundant. Thus, it is imperative to design a robust catalyst for H<sub>2</sub> generation that are made from earth abundant elements, effective in environmentally benign neutral pH medium, capable of rapid hydrogen evolution, maintaining high efficiency in low overpotential, requiring no organic additives, avoids corrosive conditions and being stable in aqueous media.&nbsp;</p> <p>Polypyridine type ligands are commonly used ligand systems in coordination chemistry, because of their ease of preparation, high stability towards air, moisture, heat, and even high potential window [5]. Moreover, these ligands offer a high surface area with a vast aromatic conjugation system that makes them electrochemically stable and provides coherent redox behaviour, which induces to use this ligand and its complexes in H<sub>2</sub> reduction reactions. Terpyridine ligand with cobalt based metal complexes are reputed as efficient catalysts for H<sub>2</sub> production. Since ILs are known to reduce the overpotential as well as increase the conversion efficiency of proton reduction reactions, we intended to utilize them synergistically along with cobalt-terpyridine metal complex for H<sub>2</sub> production.</p> <p>In this direction, we have synthesised ionic liquid tagged cobalt terpyridine and bis-terpyridine complexes and explored their electrocatalytic activity towards hydrogen generation. The synthesized ligands and complexes were thoroughly characterized by melting point, NMR, UV-Vis, FTIR, HRMS and single crystal XRD. The electrochemical investigation revealed that both the complexes show two sets of redox peaks corresponding to Co(III)/Co(II) and Co(II)/Co(I). Further, the electrocatalytic activity of both the complexes were tested towards hydrogen evolution reaction (HER) in DMF by the addition of incremental amounts of acetic acid as an external proton source. Both the complexes effectively reduced the proton in the organic medium and it is clear that the IL tagged complexes are active for HER in an organic medium in the presence of external proton source. The Co-ttpy-IL complex reduced proton at -1.7 V whereas the Co-bisttpy-IL exhibited HER at -1.9 V vs Ag/AgCl. As the complexes are water soluble, it would be highly desirable to generate H<sub>2</sub> from water medium than in the organic medium as a sustainable process. Accordingly, a controlled potential electrolysis experiment was performed in a closed H-type cell at -1.3 V vs Ag/AgCl in the presence of 0.5 mM of the complex in 0.1 M phosphate buffer (pH 7.0). During the 10 h experiment, we can notice the gas bubbles evolving from the electrode surface indicates the effective H<sub>2</sub> generation. Co-ttpy-IL exhibited higher charge consumption 20.2 C, whereas Co-bisttpy-IL consumed very less charge 3.3 C. It is obvious that the Co-ttpy-IL complex was remarkably more active than the Co-bisttpy-IL complex in terms of high current density and significant charge consumption than Co-bisttpy-IL. After realizing the remarkable electrocatalytic response of the cobalt terpyridine complex in an aqueous medium via CPE experiment, once again, the LSV was recorded from 0 to -1.5 V, which did not show any change in the voltammogram of Co-bisttpy-IL. However, in the case of Co-ttpy-IL, the onset has tremendously shifted towards positive potential after the electrolysis and it indicated that some modification has occurred on the electrode surface. SEM and XPS analysis on the modified electrode confirmed the nanostructured CoO materials stabilized with the heteroatoms of the terpyridine ligand were formed on the SPE. The CoO/SPE modified electrode exhibited a highly active and robust HER catalyst with a high current density in a neutral aqueous solution. These results provide a facile route for grafting the active electrocatalytic material onto the electrode surface from soluble molecular complexes, which may lead to their applicability in technological energy catalysis applications.</p> Senthilkumar Sellappan Copyright (c) 2021 Senthilkumar Sellappan 2021-11-06 2021-11-06 1 01 Nickel Sulfide (Ni3S2)/ Multi-walled Carbon Nanotubes (MWCNTs) nanohybrids for enhanced electrocatalytic activity towards methanol oxidation https://spast.org/techrep/article/view/918 <p>Nowadays fuel cells are considered one of the most promising renewable energy devices due to their low cost and high energy conversion efficiency. Out of these direct methanol fuel cells (DMFCs) are frequently studied due to high abundance and extraordinary energy density of methanol. A typical DMFC generally needs an electrocatalyst that can provide high number of active sites for methanol oxidation and enhanced charge transportation. Nanostructured platinum (Pt) and its alloys are mostly used as electrocatalysts in DMFC owing to higher number of active sites possessed by Pt to enhance the performance of the device <em>via </em>facilitating methanol oxidation reaction (MOR)[1]. However, high cost of Pt and its poisoning by intermediate species like carbon monoxide (CO) produced during MOR demands the production of Pt-free electrocatalysts possessing high larger number of active sites and good charge transport network[2]. Recently transition metal based sulphides, carbides and oxides based nanoparticles (NPs) are extensively studied owing to their enhanced electrocatalytic activity, high stability and low cost[3]. However, growth of these NPs leads to agglomeration resulting in lower surface area for MOR. Hence, carbonaceous materials based highly conducting network is required which can dissipate the heat used for agglomeration through heat sink effect[4]. Also carbonaceous materials alone are not capable for MOR reaction due to their lower electrocatalytic activity and lesser active sites. Therefore the nanohybrids of transition metal sulphides, oxides and carbides with carbonaceous materials like MWCNTs and rGO have been extensively used for electrocatalytic applications. In this direction, nanohybrids of multi-walled carbon nanotubes (MWCNTs) and nickel sulphide (Ni<sub>3</sub>S<sub>2</sub>) with optimized Ni<sup>2+</sup>/Ni<sup>3+</sup> ratio have been explored as anode in DMFCs to explore the synergistic effect of both the materials. Hydrothermal method has been used to synthesize MWCNTs/Ni<sub>3</sub>S<sub>2</sub> nanohybrids with three different concentrations (S1, S2 and S3). The proposed nanohybrids was chosen such a way that Ni<sub>3</sub>S<sub>2</sub> will provide the required active sites for methanol absorption and MWCNTs will act as highly conducting materials for enhanced charge transportation. These nanohybrids have been characterized through field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller analysis (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopic techniques. XRD and Raman techniques confirm the preparation of nanohybrids and their composition was calculated through XPS. FESEM images reveal that nanohybrids possess greater surface area essential for MOR which was further confirmed though BET study. Cyclic voltammograms demonstrate that the MWCNTs/Ni<sub>3</sub>S<sub>2</sub> nanohybrids with maximum Ni<sup>2+</sup>/Ni<sup>3+</sup> ratio exhibits higher electrocatalytic activity and low onset potential for MOR which is attributed to the presence of larger ionic radii of Ni<sup>2+</sup> ions. Further from the Tafel plots it has been calculated that optimized nanohybrids show highest exchange current. To understand the stability of nanohybrids, chronoamperometric studies have also been performed.</p> Viplove Bhullar Navjyoti Rajinder Singh R.K. Bedi Aman Mahajan Copyright (c) 2021 Viplove Bhullar, Navjyoti, Rajinder Singh, R.K. Bedi, Aman Mahajan 2021-09-16 2021-09-16 1 01 Electrochemical studies on Polyaniline/Titanium oxide composite for aqueous supercapacitors https://spast.org/techrep/article/view/1973 <p>Over the couple of decades, Supercapacitors (SCs) attracted tremendous attention of researchers among all energy storage systems due to its high-power density, long cycle life, and fast charge-discharge rates [1]. Development on SCs is dependent on electrode materials which play an important role in the energy storage [2]. Polyaniline (PANI) has been widely studied as electrode material because of its high conductivity, low cost, and easy synthesis [3]. However, poor cyclic stability becomes a major obstacle for pristine PANI to be used in supercapacitors. Poor cyclic stability is minimized by doping PANI with inorganic materials like TiO<sub>2</sub> which also improves the mechanical stability [4,5]. The Polyaniline (PANI) and Polyaniline - Titanium dioxide (PANI-TiO<sub>2</sub>) nanocomposites were prepared by interfacial polymerization using ammonium persulfate (APS) as oxidant. The physico-chemical properties were studied using P-XRD (powder X-ray diffraction), SEM (scanning electron microscopy), HR-TEM (high-resolution transmission electron microscope) and FT-IR (Fourier transform infrared spectroscopy). The XRD patterns of PANI and PANI-TiO<sub>2</sub> nanocomposites were given in fig.1 (A) and it is observed that PANI has a broad band at 25 degree and Titanium dioxide has many prominent peaks which were consistent with the JCPDS file (4-0477). These results of PANI-TiO<sub>2</sub> nanocomposite confirmed the presence of TiO<sub>2</sub> in PANI matrix. The intensity of peaks in nanocomposite decreased as expected due to the presence of PANI. The TEM image was shown as inset in fig.1 (A). It is observed that, PANI was wrapped around TiO<sub>2</sub> particles and TiO<sub>2</sub> particles were well dispersed in PANI matrix.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; To analyse the electrochemical behaviour of the PANI and PANI/TiO<sub>2</sub> nanocomposites, Cyclic voltammetry (CV), Galvanostatic Charging and Discharging (GCD), and electrochemical impedance spectroscopic (EIS) measurements were employed using CHI 608E electrochemical workstation at room temperature. The electrochemical measurements were conducted in a three-electrode system consisting of toray carbon paper coated with active material as a working electrode, saturated calomel electrode as a reference electrode, and platinum wire as a counter electrode in 1 M KOH solution. CV responses were recorded using cyclic voltammetry at different scan rates and charge-discharge curves were recorded using chronopotentiometry at different current densities. The CV responses and discharge curves of PANI and PANI-TiO<sub>2</sub> were shown in fig.1 (B) and fig.1 (C) respectively. The PANI-TiO<sub>2</sub> nanocomposites exhibited maximum specific capacitance (Cs) of 1456 F/g at a scan rate of 5 mV/s and 536 F/g at a current density of 5 A/g. These nanocomposites also delivered a maximum energy density (ED) of 8 W h Kg<sup>-1</sup> at a corresponding power density (PD) of 598 W kg<sup>-1</sup>. A higher solution resistance (R<sub>s</sub>-1.49 Ω) and lower charge transfer resistance (R<sub>ct</sub>-0.33 Ω) were observed in PANI-TiO<sub>2</sub> nanocomposites. Symmetric supercapacitor prototype (fig.1(D)) was fabricated using two electrodes coated with PANI-TiO<sub>2</sub> nanocomposites and electrically isolated from each other by porous membrane pre–soaked with the electrolyte solution. The device achieved specific capacitance of 145 F/g and 46 F/g at 5 mV/s and 2.5 A/g. The outstanding capacitive retention of 70% after 2000 cycles in device can enable the PANI/TiO<sub>2</sub> hybrid composites to be a promising electrode material for future generation energy storage.</p> <table> <tbody> <tr> <td width="258"> <table> <tbody> <tr> <td width="21">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> <p><br><strong>A</strong></p> </td> <td width="265"> <table> <tbody> <tr> <td width="169">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> <p><br><strong>B</strong></p> </td> </tr> <tr> <td width="258"> <table> <tbody> <tr> <td width="16">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> <p><br><strong>C</strong></p> </td> <td width="265"> <table> <tbody> <tr> <td width="163">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> <p><br><strong>D</strong></p> </td> </tr> </tbody> </table> <p><strong>&nbsp;</strong></p> <p><strong>Fig.1.</strong> (A) XRD patterns of PANI, PANI-TiO<sub>2</sub>, TiO<sub>2</sub> (inset-TEM image of PANI-TiO<sub>2</sub> nanocomposite), (B) CV patterns of PANI and PANI-TiO<sub>2</sub> nanocomposite, (C) Charge-discharge curves of PANI and PANI-TiO<sub>2</sub> nanocomposite, (D) Plot of capacitance retention of PANI-TiO<sub>2</sub> nanocomposite.</p> Radhika M G Rudranna Nandihalli Sudha Kamath M K Copyright (c) 2021 Radhika M G, Rudranna Nandihalli, Sudha Kamath M K 2021-10-09 2021-10-09 1 01 Role of mixed inorganic additives in controlling the dendrite growth in lithium metal anodes https://spast.org/techrep/article/view/2700 <p>Ever since the first commercialization in 1991, Lithium-ion batteries (LIB) have been effectively utilized in smart electronic gadgets, and are now progressively breaking into the markets of electric cars and grid energy storage systems [1]. Lithium metal anode (LMA) has a theoretical specific capacity of 3860 mAhg<sup>-1</sup>, which is 10 times higher than that of the typical lithiated graphite anode LiC<sub>6</sub> (372 mAhg<sup>-1</sup>) with low mass density (0.53 gcm<sup>-3</sup>) and low anode potential (-3.04 V), making it as a viable anode material for lithium batteries. However, usage of LMA is severely hampered by the formation of undesirable Li dendrites and low columbic efficiency during continuous Li<sup>+ </sup>plating and stripping process [2]. Another important barrier in exploring LMA in battery applications is the volume expansion that occur when the SEI layer breaks during the Li<sup>+</sup> plating/striping process, which further contributes in the rapid capacity fading The most viable solutions to overcome the aforementioned problems include surface modification of LMA, inducing electrostatic shield mechanism using electrolyte additives, exploring the use of functional separator and high modulus solid state electrolytes etc., [3]. These serious drawbacks can be offset by engineering the electrolyte system, which not only delivers the fast Li<sup>+</sup> ion flow between the cathode and anode but also helps in maintaining the electrode/electrolyte interfaces stable, allowing for a high voltage of ~4 V. During the electrochemical process, the electrolyte decomposition products will make a thick layer on the electrode, which in turn increases the interfacial resistance as well as the cell polarization, thereby affecting the performance characteristics of the battery. Adding a film additive into the electrolyte will lead to the formation of film layer on the anode surface, eventually enhancing the cycling stability of the battery [4]. Hence, it is desirable to substitute the organic additive with inorganic liquid electrolyte to overcome these fundamental issues. Here, we demonstrate to suppress the dendrite growth and stabilize the LMA using Lithium difluoro(oxalato)borate (LiDFOB) and tetraethyl orthosilicate (TEOS) as primary and secondary additives in commercial LiPF<sub>6</sub> salt electrolyte. While the incorporation of LiDFOB additive potentially reduced the overpotential values, thereby improving the cycling stability in comparison to commercial electrolyte in Li/Li symmetric cell, the performance characteristics dramatically enhanced on using TEOS as the secondary electrolyte additive (Fig. 1 (a)). In addition, rate capabilities of the NMC/Li full cells are apparently higher on using the additives in the electrolyte system (Fig. 1 (b)). The profound effect is attributed to the formation of film layer on the lithium surface, which eventually regulates the lithium deposition during the electrochemical cycling. Thus, incorporation of multiple inorganic additives in the commercial electrolyte system paves a way in making high performance lithium-metal batteries.&nbsp;</p> <p><img src="https://spast.org/public/site/images/irfan/fig.-1.jpg" alt="Fig. 1 (a) Voltage curve of Li/Li cells fabricated using electrolyte with/without additives, Fig 1 (b) great performance of NMC/Li cells fabricated using electrolyte with/without additives" width="1280" height="720"></p> Irfan H Copyright (c) 2021 Irfan H 2021-10-21 2021-10-21 1 01 Efficient Co-MOF/CNT based symmetric Supercapacitor for high performance electrochemical application https://spast.org/techrep/article/view/2049 <p><span style="font-weight: 400;">Recently, Metal organic frameworks are stealing great interest as a new, trendy and crystalline material for energy storage systems. This crystalline porous network formed by the co-ordination bonding of metal ions and organic ligands. </span><span style="font-weight: 400;">MOFs tremendously used material in energy storage systems, Since MOFs are well known for attractive architectures which promotes three dimensional structure with high specific surface area and uniform pore size distributions.</span> <span style="font-weight: 400;">The advantages boost the usage of MOFs in vast applications such as catalysis, gas separation and storage, drug delivery, imaging and sensing and also optical and magnetic materials [1]. There were various MOFs have been prepared for the supercapacitors applications, special attraction was taken by nickel and cobalt metal ions-based electrode materials, since the nickel and cobalt have the advantages of high electrical and thermal properties</span><span style="font-weight: 400;">, hence used as various supercapacitors based electrode materials and their composites</span><span style="font-weight: 400;"> The lacking in utility of metal organic frameworks is its less chemical stability and ionic conductivity. To improve this shortcoming of MOFs various strategies have been developed.</span><span style="font-weight: 400;"> In the present study, we have fabricated a Co- based metal organic framework (Co-MOF) over carbon nanotube through highly reliable and industrially applicable electrochemical deposition technique. The technique provide uniform deposition of MOF crystals over a surface of carbon nanotubes. The material was casted layer by layer over a conducting Ni foam substrate. The prepared electrode material was characterize by X-ray diffraction (XRD), Scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), cyclic voltammetry(CV), Galvanostatic charge discharge (GCD) and Electrochemical impedance spectroscopy(EIS) for analyzing the structural, morphological and electrochemical parameters. The incorporation of carbon nanotubes into Co-MOF enhances its conductivity and cycle life. As prepared Co-MOF/CNT material delivers high specific capacitance of 1294.54 Fg</span><span style="font-weight: 400;">-1</span><span style="font-weight: 400;"> at 2Ag</span><span style="font-weight: 400;">-1</span><span style="font-weight: 400;"> current density in three electrode cell configuration. The electrode was also proven to have high cyclic stability of 10000 cycles with 80% capacitance retention. To further explore practical application of as prepared electrode, a symmetric supercapacitor based on Co-MOF/CNT was fabricated, and this device was operated in voltage range of 0 to 1.0 V in 2M KOH electrolyte. The prepared device exhibits high energy density with magnificent stability of 100000 cycles with 94.23% capacitance retention. This work demonstrates a new approach and efficient method to enhance the performance of supercapacitors.</span></p> <p>&nbsp;</p> <p><strong>Keyword:&nbsp; Metal organic Frameworks, Co-MOF/CNTs, hybrid material, Long cycle life, Supercapacitor</strong></p> <p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <img src="https://spast.org/public/site/images/ritikasharma/image-abstract.jpg" alt="" width="572" height="235"></p> <p><span style="font-weight: 400;"><strong>Fig 1:</strong> Graphical abstract of as prepared Co-MOF/CNT electrode for supercapacitors</span></p> Ritika Sharma Copyright (c) 2021 Ritika Sharma 2021-10-08 2021-10-08 1 01 Novel design and numerical analysis of 3D porous electrodes for Micro-Supercapacitors https://spast.org/techrep/article/view/2476 <p><strong>Why micro-supercapacitors</strong>?</p> <p>Miniaturized electronic components used in a portable, wearable, and implantable smart electronics require the energy harvesting technologies to realize their own energy from mechanical, thermal, or ambient light energy from the environment and convert into electricity[1–3]. But, intermittence and instability of such resources, microscale electrochemical energy storage (EES) units are required as the energy buffer to support these electronic devices. The available microscale EES devices are divided into micro-batteries (MBs) and micro-supercapacitors (MSCs). MBs offer substantially high energy density (~ 1mWh/cm<sup>2</sup>) but lower areal power density (&lt; 5 mW/cm<sup>2</sup>) and limited-service life (few thousand cycles)[4]. On other hand, MSCs provides ultrahigh areal power density (&gt; 10 mW cm<sup>-2</sup>), long cycle life (&gt; 10000 cycles), quick charge and supply moderate energy (&lt; 0.1 mWh cm<sup>-2</sup>)[5,6].</p> <p><strong>Challenge in fabrication of MSCs - </strong></p> <p>Although the MSCs have better power density than MBs, enhancing the energy density remains a challenge. [7,8] The capacitance of conventional 2D planar MSCs is constrained due to the lesser amount of active materials per unit area [9,10]. Three-dimensional (3D) MSCs offer high energy/power autonomy, long charge-discharge cycles, and fast charge-discharge rates. In addition, 3D electrodes extend the benefits over 2D electrodes such as – a) much larger surface area, b) reduced ion diffusion length between electrodes, and c) low cost [11]. In recent years, strenuous efforts have been taken to develop 3D electrodes for MSCs, and significant progress has been made. Figure 1 depicts various micro-truss structures employed in the past by various researchers for sandwich and interdigitated configuration of MSC electrodes.[12–16]. Researchers have highlighted several challenges related to the design of lattice structures with high surface area while maintaining their strength, as well as to increase electrode conductivity and capacitance. Various research efforts have been made to overcome these challenges and improve the performance of the MSCs.</p> <p>Figure 1. Micro-truss structures a) Octet [13] and b) Honeycomb Structure [14,15] employed for MSCs.</p> <p><strong>Novel Concept - </strong></p> <p>This proposal brings up a unique in-plane design of “<em>Parallel cylindrical holes with staggered arrangement</em>” for MSC electrodes. The objective of this research is to design and numerically analyse the recently employed 3D octet structure. The physical and mechanical performance of the same was compared with the proposed 3D porous structure (Fig. 2). To avoid edging and the presence of sharp corners in the earlier truss structures and to increase the surface area of the electrode, cylindrical microporous holes (~ 40 µm diameter) are made in the proposed structure. The axes of these holes are parallel to each other.&nbsp;</p> <p>Figure 2. Proposed design of parallel cylindrical holes with staggered arrangement.</p> <p>The FEA analysis under uniaxial tensile loading was carried out. Results showed that, with similar stress values, the staggered cylindrical holes structure demonstrated higher surface area than the octet structure, which will enhance the electrochemical performance of the MSC. This design also demonstrates higher mechanical strength due to the continuity of the material. This unique, simplified design will exhibit significantly less ionic resistance due to the continuity of the pores. This design simplicity will also permit the unconventional processing methods to produce such 3D MSC electrodes with higher surface area. The authors are confident that the proposed structure will significantly improve the energy and power density values of the 3D MSC.</p> SANDEEP AHANKARI Copyright (c) 2021 SANDEEP AHANKARI 2021-10-13 2021-10-13 1 01 THEORETICAL STUDIES ON THE ROLE OF WATER IN IONIC LIQUIDS AT ZIF (IL@ZIF) COMPLEX FOR GAS STORAGE AND SEPARATION APPLICATIONS https://spast.org/techrep/article/view/605 <p>One of the major problems we have always faced and still facing is the vast amount of toxic gases expelled into the atmosphere mainly during manufacturing of many of the day-to-day commodities we all use.[1,2] The selective adsorption and storage of gases from various industrially important mixtures using membrane technology is studied in order to find a suitable solution for the concern.[3–5] This study is conducted in order to give a different perspective on the gas separation and storage capabilities of the larger frameworks like zeolitic imidazolate frameworks (ZIFs).[6] Large framework molecules like ZIFs combined with ionic liquids (ILs)[7,8] are used in this study to check their gas adsorption efficiency in presence of a single water molecule. We have taken 1-butyl 3-methylimidazolium ([BMIM]<sup>+</sup>) cation along with five different anions for this study.[9] We used both hydrophilic and hydrophobic ILs. Also the IL based complexes are studied with addition of water molecule in two different approaches. We have added water alone into previously optimized geometries[10] of IL@ZIF in one method, while we added water and IL to the ZIF-8 confinement simultaneously in the second method. The selection of the different approaches for water addition is to gather information about the interaction pattern of water with IL and ZIF and also of these molecules with one another in presence of water. We have used the complexes to study their adsorption capabilities towards CO<sub>2</sub> and also their selectivity nature towards CO<sub>2</sub> in a binary mixture of CO<sub>2</sub> and N<sub>2</sub>. The optimization of single water molecule inside the IL@ZIF-8 and IL-water mixture inside ZIF-8 are done using DFT based methods in CP2K[11] software. Also the gas adsorption, separation studies are carried out using RASPA[12] simulation package. Grand canonical Monte Carlo simulations are used in this aspect. This study gives a detailed insight about how the addition of water molecules affect the gas storage ability of the IL@ZIF-8 complexes. This gives some important information on real time gas separation from flue gas mixtures.</p> Anoopa Thomas Aakhash Cheriyan Muthuramalingam Prakash Copyright (c) 2021 Anoopa Thomas, Aakhash Cheriyan , Muthuramalingam Prakash 2021-09-16 2021-09-16 1 01 Abnormal Synergistic behavior of metal chelates of 1,10-Phenanthroline scaffold for enhancing Hydrogen Evolution from water https://spast.org/techrep/article/view/2834 <p>The design and development of metal complex architecture with a multidenate heterocyclic organic compound that modulates hydrogen evolution from water. To achieve effective hydrogen evolution efficiencies of metal chelates bearing Phenanthroline scaffold, [ML].2(OAc) (L-1,10-Phenanthroline analogous contains aromatic core; M=Co, Zn, Cu &amp; Ni ions) were designed and synthesised. A square-planar arrangement with moderate distortion was attributed to the above metal chelates based on spectroscopic data and analytical studies. The experimental observations highlighted that metal chelates were effective towards hydrogen evolution under photochemical and electrocatalytic condition. During the photochemical process, the metal chelate was combined with fluorescein (photosensitizer) and triethylamine (sacrificial e‑ donor) showed enhanced hydrogen evolution under photochemical irradiation that correlates with electronic and conjugation of ligand. Copper complexes with the highest TON and TOF values (11,500 and 7800) had the best catalytic activity at pH 10.6 in CH<sub>3</sub>CN:H<sub>2</sub>O (1:1 ratio). All of the promising findings offers novel paths for hydrogen production with chromophores and metal catalysts. Due to its abnormal synergistic behaviour imparts the potential of redox characteristics, metal ions with highly conjugated ligands showed hydrogen production with impressive results. This research could pave the way for the growth of metal complex as hydrogen generation catalysts.</p> K Nagashri Copyright (c) 2021 K Nagashri 2021-10-19 2021-10-19 1 01 Effects of KOH Activation on the Supercapacitive performance of Kenaf fibre-based activated carbon https://spast.org/techrep/article/view/1536 <p>Supercapacitors are devices used for the storage of electrical energy that can be used in motor starters, static random access, power grids and regenerative breaking in cars [1]. Supercapacitors have high capacitance compared to conventional dielectric capacitors andhave drawn many interests among researchers due to possible energy storage by the utilization of renewable energy sources. Batteries have high energy density but low power density whereas supercapacitors have high power density and cycling stability. Fast charging and discharging of large amounts of electrical energy make supercapacitors ideal for short-term energy storage [2]. The benefits of using supercapacitors compared to batteries are that it has high power density, longer life cycles, fast charging and discharging capabilities and safer compared to batteries [3]. It also has wide operating temperatures [4]. There are three types of supercapacitors, which are electrical double-layer capacitors (EDLC), pseudocapacitors and hybrid capacitors [5]. The working principle of EDLC are that the capacitance is produced through the accumulation of static charge at the electrode/electrolyte interface, where charged ions undergo adsorption and desorption. Hence, materials with high surface area with many pores are required to exhibit excellent capacitance [6]. Many attempts were made to improve the performance of the carbon electrode to achieve high specific capacitance. Commonly used materials are carbon fibres, carbon nanotubes, carbon aerogels, graphene and activated carbons [7]. Generally, the process of synthesizing activated carbon is relatively simple that involves carbonization and is followed by chemical activation using a suitable activating agent. It is also much cheaper compared to other methods of generating carbon especially for biowaste [8]. Kenaf fibre is a renewable source of biomass and is abundantly available.</p> <p>Kenaf fibre has been successfully explored for low cost activated carbon for supercapacitor application via two-step synthesis method. Pre-carbonized carbon (PC) is synthesized by pyrolysis at 500 °C in an argon gas environment. Activated carbon is synthesized by activating the pre-carbonized carbon at 700 °C for 1 h. This paper demonstrates the need for activation of pre-carbonized carbon to further improve the surface area which increases the specific capacitance of the fabricated electrode. The specific capacitance achieved from activated carbon and pre-carbonized carbon from kenaf fibres is compared. This comparison is made to present the importance of activation and to study the change in the porous structure of the activated carbon before and after activation. The electrochemical performance of the fabricated electrode was analyzed using Cyclic Voltammetry (CV) and Cyclic charge/discharge (CCD) studies in 1 M KOH electrolyte. Specific capacitance is calculated from the discharge time in CCD analysis. Fig.1 shows the CV curve of both pre-carbonized carbon and activated carbon. It can be observed that AC has a significantly larger quasi rectangular shape compared to PC. From the CCD study, the discharge time of electrode from AC have significantly increased compared to the electrode from PC. The activated carbon from kenaf produced the highest specific capacitance of 224.3 F g<sup>-1</sup> at 0.5 A g<sup>-1</sup> compared to the specific capacitance of pre-carbonized carbon of 75.5 F g<sup>-1</sup> at 0.5 A g<sup>-1</sup> as shown in Fig. 2. Table 1 shows that the activated carbon has better specific capacitance retention at higher current densities compared to pre-carbonized carbon. From this, it is concluded that activation of biowaste fibres like kenaf is needed for the fabrication of high-performance supercapacitor electrodes.</p> THILAGESHWARAN SUBRAMANIAM M N M Ansari Syam G. Krishnan Mohammad Khalid Copyright (c) 2021 THILAGESHWARAN SUBRAMANIAM, M N M Ansari, Syam G. Krishnan, Mohammad Khalid 2021-10-07 2021-10-07 1 01 Substantial Benefits of Surface Modified Rhombohedral α-Fe2O3 High Stability Electrode for Lithium Energy Storage Device https://spast.org/techrep/article/view/1218 <p>In the field of energy storage devices, lithium-ion batteries (LIBs) are act as one of the major tools to store the energies. LIBs are commonly used as a current storage device for electronic gadgets such as laptops, smart watches, mobile phones, and modern electrical vehicles (EVs), because of its excellent energy storage capacity, low self-discharge, high durability and improved energy and power density. [1] The commercial negative electrode for LIBs are carbon-based compounds, which containing the low specific capacity (372 mAh g<sup>-1 </sup>for graphene). To overcome this issues, Transition Metal Oxides (TMO) is focused to use as negative electrode for rechargeable LIBs. A variety of TMO (TM = Ni, Co, Cu, and Fe) [2] have been used as anode material for LIBs fabrication, due to their high theoretical capacity. Among those metal oxides, hematite α-Fe<sub>2</sub>O<sub>3</sub> is technologically important because of its <strong>substantial benefits</strong> <strong>of </strong>electrical and magnetic properties, cost-effective and environmental benign. The high theoretical capacity of the hematite α-Fe<sub>2</sub>O<sub>3</sub> is 1007 mAh g<sup>-1</sup>, but its delivers poor practical capacity due to the less conductivity, unstable structure and large volume changes while undergoes the cycling process. The formation of unstable or collapsing the structure of α-Fe<sub>2</sub>O<sub>3</sub>, when undergoes the intercalation/de-intercalation of Li<sup>+ &nbsp;</sup>on into the core structure, the volume change of α-Fe<sub>2</sub>O<sub>3 </sub>is much higher ⁓96 % [3] this is leading to the disintegration of the anode within the cycles, which is highly impact the quick capacity fading and decaying of LIBs work function. The main objective of this current work is to overcome the above-mentioned issues, since the electrochemical performance of the α-Fe<sub>2</sub>O<sub>3 </sub>is depends on it size and morphologies. The nanostructure electrodes offer a large surface area which is create a short path of lithium-ion diffusion and more active reaction sites. It’s highly helpful to enhance the electrochemical properties of rechargeable LIBs. Here in we reported the rhombohedral α-Fe<sub>2</sub>O<sub>3 </sub>surface is modified/tuned with conducting material (X-α-Fe<sub>2</sub>O<sub>3</sub>) used as a negative electrode for LIBs. The electrode materials are synthesized via pechini method followed by calcination processes. The crystallography phase, structure and surface morphologies of as-synthesized X-α-Fe<sub>2</sub>O<sub>3</sub> are analysing via Powder X-ray Diffraction (XRD), High-Resolution Scanning Electron Microscopy (HR-SEM) and High-Resolution Transmission Electron Microscopy (HR-TEM), the electrochemical properties of as-synthesized X-α-Fe<sub>2</sub>O<sub>3 </sub>are analysized via Cyclic Voltammogram (CV), Charge-Discharge Techniques (CD), and Electrochemical Impedance Spectroscopy (EIS). The XRD result confirms the phase purity of as-synthesized α-Fe<sub>2</sub>O<sub>3</sub>. The pristine α-Fe<sub>2</sub>O<sub>3</sub> exhibits an excellent initial discharge capacity of 947 mAh g<sup>-1</sup> at 0.1C rate followed by 25<sup>th</sup> cycle discharge capacity is 117 mAh g<sup>-1</sup>, over 50<sup>th</sup> cycle the discharge capacity of &nbsp;67 mAh g<sup>-1</sup> with 100 % of columbic efficiency (CE) in the potential window of 0.01 to 3.0V. When compare to pristine α-Fe<sub>2</sub>O<sub>3</sub>, the coated X-α-Fe<sub>2</sub>O<sub>3</sub> reveals the excellent initial discharge capacity of (809 mAh g<sup>-1</sup>) at 0.1C rate followed by 25<sup>th</sup> and 50<sup>th</sup> cycle exhibits discharge capacity of &nbsp;X-α-Fe<sub>2</sub>O<sub>3 </sub>is 137 and 110 mAh g<sup>-1</sup> with 100 % of CE respectively. When compare to α-Fe<sub>2</sub>O<sub>3</sub>, the X-α-Fe<sub>2</sub>O<sub>3 </sub>reveals the good electrochemical performance and stable cycling for LIBs. Thus the X-α-Fe<sub>2</sub>O<sub>3 </sub>is a suitable electrodes for next generation energy storage systems.</p> kasiviswanathan kavibharathy Copyright (c) 2021 kasiviswanathan kavibharathy 2021-09-28 2021-09-28 1 01 An Eco-friendly smart battery-less Wi-Fi-based environmental condition monitoring system for precision agriculture https://spast.org/techrep/article/view/1594 <p>Agriculture is the primary source of food for the world's population. The agriculture industry has seen many changes in the last few decades. One of the most critical changes is using small electronic devices to manage an optimum environmental condition such as soil moisture, temperature, and humidity for crops Therefore, with the help of electronics products, farmers can achieve a good and quality yield. Every electronics equipment needs a power source, and on most occasions, environment condition monitoring devices use a rechargeable battery. Therefore, the lifetime and performance of the device depend on the battery life of the device. This study is focused on an eco-friendly Smart battery-less Wi-Fi-based environment condition monitoring system for precision agriculture to overcome the limitations mentioned above. In this design, a small 6 V/0.6 W photovoltaic module (PV) with a 5.5 F supercapacitor is used as an energy source, which is a sustainable, eco-friendly and cost-effective solution for agricultural devices. The performance of the proposed device may change due to variation in power generation by PV module due to variation of solar irradiance of the daytime. Hence, a performance management algorithm is used to manage the power dissipation of the device's internal circuitry. The proposed device uses a specially designed low power consuming supercapacitor charge discharging circuit to manage the device performance and power. The Schmitt-trigger based power management circuit controls the output voltage of the circuit for the ESP8266 microcontroller at 3.3 V. The BME680 air quality sensor and capacitive soil moisture sensors are used for environmental condition measurements. With the help of this study, conventional battery-powered agricultural devices can be replaced using the proposed low-cost solar-powered supercapacitor assisted battery less agricultural monitoring devices that are Wi-Fi enabled and IoT ready. This solution will not only be of low maintenance cost but also will help to reduce the global e-waste collection. Hence this study helps to protect our environment as well as human and animal life.</p> Aruna Ranaweera Ishara Rajapaksha Kasun Piyumal Jehan Seneviratne Copyright (c) 2021 Aruna Ranaweera, Ishara Rajapaksha, Kasun Piyumal, Jehan Seneviratne 2021-10-01 2021-10-01 1 01 High energy storage efficiency and electrocaloric effect in Pb-free Ba0.85Ca0.15Hf0.10Ti0.90O3 ceramics for sustainable green energy applications https://spast.org/techrep/article/view/1093 <p>The growth of the economy and culture, as well as the fossil-fuel problem, global warming, and environmental pollution, have all driven huge efforts to build clean and sustainable energy alternatives in recent years. Compact refrigeration and energy conversion devices are in high demand these days. Dielectric/ferroelectric capacitors exhibit a high power density and fast charging/discharging speed than other energy storage devices, but their low energy storage density has limited their applications for commercialization. Also, electrocaloric effect-based solid-state cooling devices are having the potential to replace present vapor-compression-based refrigeration. However small adiabatic temperature change (ΔT) and narrow temperature span of ΔT of ferroelectric ceramics at room temperature limited their application for practical cooling devices. So, the research community is focusing to develop new ferroelectric materials that can have high ΔT, energy storage density, and efficiency at room temperature [1-4]. Pb-free BaTiO<sub>3</sub>-based ceramics can achieve high energy storage density and large ΔT because their properties can be easily tailored by doping and fabrication conditions, and thus have the potential for clean energy applications [4, 5]. Porosity has great effect on the dielectric, energy storage, and electrocaloric properties of ferroelectric ceramics [6, 7]. Here in this work, we have successfully synthesized Pb-free Ba<sub>0.85</sub>Ca<sub>0.15</sub>Hf<sub>0.10</sub>Ti<sub>0.90</sub>O<sub>3</sub> (BCHT) ceramics by sol-gel method (fig.1A) and their structural, dielectric, ferroelectric, electrocaloric, and energy storage properties are presented in fig.1B. The room temperature XRD patterns show pseudo cubic type perovskite polycrystalline structure without any secondary phase. Fig.1(a) shows Rietveld refinement of two-phase co-existence model tetragonal (P4mm) and cubic (Pm3m) phase, with each phase contribution of 58 % and 42 % respectively. Fig.1(b) shows the FESEM micrograph of porous BCHT ceramic. The average grain size and pores diameter of around 2.5 µm and 1 µm are observed. The volumetric porosity of BCHT ceramic is found to be around 11 %. Fig.1(c) shows Raman spectra of BCHT ceramics recorded at room temperature. The spectra exhibit widened vibrational peaks, which indicate a phase transition from tetragonal to cubic phase. Temperature-dependent dielectric properties are shown in fig.1(d) at different frequencies 1kHz, 10kHz, 100kHz, and 1MHz. The dielectric constant characteristic curves show slight variation in the lower temperature region and very broad dielectric peaks are observed in temperature range 25 to 120 <sup>0</sup>C at various frequencies, this is due to porosity [8]. Fig.1(e) and fig.1(f) show temperature-dependent P-E loops and P-T curves at the various electric fields from 0 to 20 kV/cm respectively. The adiabatic temperature change ΔT and entropy change ΔS have been calculated by an indirect method using Maxwell relations. &nbsp;The ΔS and ΔT are calculated at a comparatively low electric field of 20 kV/cm as shown in fig.1(h) and fig.1(i). The room temperature value of ΔS and ΔT are -0.207 and 0.157 respectively, with a wide temperature span of 50 K. Temperature-dependent energy storage properties of BCHT ceramics are investigated by using temperature-dependent P-E loops.&nbsp; Energy density (W<sub>tot</sub>), recoverable energy density (W<sub>rec</sub>), and energy storage efficiency (η) are estimated by using equations W<sub>tot</sub>, W<sub>rec</sub>, and η&nbsp;% [1]. Fig.1(g) shows temperature-dependent W<sub>tot</sub>, W<sub>rec</sub>, and η of BCHT ceramics. &nbsp;The observed W<sub>tot</sub>, W<sub>rec</sub>, and η values at Room temperature are 84.43 mJ/cm<sup>3</sup>, 64.38 mJ/cm<sup>3</sup> and 76.25 % respectively. The W<sub>tot</sub> and W<sub>rec</sub> values decreases and η increase with increasing temperature, the maximum value of η ~ 85.03 % has been observed at temperature 80 <sup>0</sup>C. In conclusion, the high energy storage and electrocaloric properties of BT-based ceramics can be achieved by optimizing porosity level within the material and high applied electric field (high dielectric breakdown strength), So as to meet the desired performance for possible device applications in the field of sustainable green energy.</p> REVATI NANDAN Nainjeet Singh Negi Sanjeev Kumar Copyright (c) 2021 REVATI NANDAN, N. S. Negi, Sanjeev Kumar 2021-09-21 2021-09-21 1 01 Critical Perspective on the Industry-centred Engineering of Single Crystalline NCM Cathodes https://spast.org/techrep/article/view/448 <p>Ever growth in the demand of the energy has catapulted us to explore various energies and henceforth, multiple energy storage devices have been under intense research that can quench this desire. To meet these ends, among the various cathode active materials, Nickel(Ni) rich polycrystalline cathode materials have been known to aptly serve the purpose. Yet, with an increase in the voltage, temperature and the number of cycles, these Ni polycrystalline rich cathode active materials were found in a deteriorated condition and have yielded inferior performances. This is mainly attributed to the polycrystallinity of the cathode materials where micro/Nano-sized primary particles have aggregated to form the secondary particles.[1] As the number of charge-discharge cycles increase, battery operating voltage goes beyond 4.2 V, the anisotropic mechanical strain arises in the c direction of the layered structure and the non-uniform distribution of the strain in the randomly oriented primary particles causes the intergranular cracking, which initiates the parasitic side reactions. These inter-grain cracks lead to rapid impedance growth and capacity decay. Owing to few of these cracks that arise during the calendaring process, the compact density of the electrode and the volumetric density are limited to a considerable extent.[2] Adding to these setbacks, cation mixing has been widely reported as a factor in plummeting the output performances. As a result, the scientific community has focused on the Single Crystalline NCM cathode materials to combat this below par performance. The absence of grain boundaries in the intrinsic structure, high mechanical strength, high thermal stability, and controllable crystal faucet led to the major EV battery sectors eyeing for the development of SC cathodes. Yet, there are challenges to overcome in the SC cathodes like larger crystals hinder the Li+ transport and longer ionic transport pathway, this leads to disappointing electrochemical performance. In recent months, we have seen immense growth in publication of papers in SC cathodes suggesting various synthesis methods, various strategies to overcome the challenges involving cation doping and surface coating which involves less complicated processes and scalability which is an important parameter in the perspective of the industries. Dopants or Coating elements have complementary effect and mitigate the losses that have been observed in the pristine material. Various dopants such as Aluminium, Magnesium,[3] Boron [1], Tungsten, Vanadium have been doped to enhance the ability to tackle the anomalies at high temperatures and voltages. Through this perspective article we wish to elucidate the crucial factors that facilitate the growth of SC-NCM Cathode, on-going research on the SC-NCM, viable dopants and coating materials that could possibly be used to enhance the performance, future scope, and scalability of SC-NCM at Industrial level. Additionally, we have presented the preparation of the pristine Single crystalline NCM Cathode and Boron doped Single Crystalline NCM cathode material (B SC NCM) through Co-precipitation method in Continuous stirred Tank Reactor, characterization results of the precursor are presented, Fig. 1. This perspective article explores the possible solutions and lapses that facilitate a conducive environment to the scientific fraternity in reducing the need gap in the energy storage sector.[4] Identification of lapses in the pivotal aspect in battling this ever-growing problem. Through this paper, we aspire that it leads to manufacturing of batteries that would effectively operate for longer durations and support in lowering the amount of toxic chemicals that are released into the atmosphere.</p> Praneash Venkatachalam Chanakya Karra Kamala Kumari Duru Asha Anish Madhavan Pardha Saradhi Maram Sujith Kalluri Copyright (c) 2021 Praneash, Chanakya, Kamala Kumari , Asha Madhavan, Pardha Saradhi , Sujith Kalluri 2021-09-15 2021-09-15 1 01 The need of development of Na -ion batteries in the present scenario https://spast.org/techrep/article/view/1443 <p>Countries like India have no lithium resources and they need to depend on other countries for the application of energy storage devices. Lithium resources are draining day by day and costs are increasing accordingly. It's time to develop alternative rechargeable batteries like Na, Mg, Al, and fluoride-ion batteries. Sodium is the cheapest and safest material of all. Development of Sodium based cathode, anode and electrolyte materials are needed urgently to fill the need of energy requirements all over the world. So, we started preparing sodium-based solid electrolytes for use in all-solid-state sodium-ion batteries. We compared different sodium precursors to enhance ionic conductivity.</p> Y Bhaskara Rao Copyright (c) 2021 Y Bhaskara Rao 2021-10-07 2021-10-07 1 01 A Design of high potential organic cathodes for Lithium – ion batteries, using first- principle DFT modelling approach. https://spast.org/techrep/article/view/1573 <p>The Li-ion battery technology is very efficient because of the significant energy and power density [1]. While manufacturing the commercial prototype cathode materials, the 3d transition metals like Co, Ni, Cr, Mn, and Fe are extensively used. However, they usually suffer from high production costs due to less abundant raw materials [2-3]. Apart from the commercial cathodes, toxic metals like Co and Ni pollute the earth surface and need to be recycled. Alternatively, many research groups focus on developing cathode materials consisting of earth-abundant elements viz., C, H, S, N, O. The organic-based materials are promising candidates for the advancement of Lithium-ion/sodium – ion/dual- ion battery technologies [4-5]. Because low-cost, nontoxic nature of organic compounds makes them promising alternatives to their inorganic counterparts [6]. Among the many examples of organic compounds, carbonyl group-containing compounds are most popularly used for rechargeable batteries because they have a high theoretical capacity with good redox chemistry. Each carbonyl group can except electron reversibly favours stable charge/discharge. However, they a few challenges for commercial applications, namely, high solubility in organic solvents, multiple synthesis steps involved during the synthesis process, low electronic conductivity due to wide intrinsic bandgap and relatively low redox potentials (lower than the 3V). Many research groups are working to resolve the obstacles mentioned above [7-8].</p> <p>In the present study, our emphasis is on <strong><em>pyrenetetrones</em> </strong>compounds as they possess high redox potential due to the multi redox centres of carbonyl groups present in the structure [9]. DFT methods are applied to investigate the redox properties of substituted pyrenetetrone compounds, such as 4,5,9,10-tetroane (PT), 2,7- difluoropyrene-4,5,9,10-tetroane (PT-2F), 2,7-trifluoropyrene-4,5,9,10-tetroane (PT-2CF3), 2,7- diacylchloropyrene-4,5,9,10-tetroane (PT-2AcCl), 2,7- dicyanopyrene-4,5,9,10-tetroane (PT-2CN), 2,7- dinitropyrene-4,5,9,10-tetroane (PT-2NO<sub>2</sub>), 2,7- diaminopyrene-4,5,9,10-tetroane (PT-2NH<sub>2</sub>) in Figure (A). the computed redox properties are calculated based on the nature of the substituents like EWG (electron withdrawing) and EDG (electron-donating group) present on the pyrene ring. the electronic properties are affecting with addition of any substituent to the core molecules, first, we find out the higher electron acceptability character containing pyrenetetrone molecules and performed a lithiation process. This investigation reveals EWG shows higher redox potentials than the EDG. Among all the examples, PT-2CN shows higher redox potential ~ 3.6V Li/Li<sup>+</sup> with two lithium binding, apart from that PT-2CN maintain a stable voltage until four lithiums binding to the structure. Also, we calculated the theoretical charge capacities of the highest redox potential exhibiting molecules. Finally, we found that PT-2CN highest redox potential and theoretical charge capacities. It can store four lithiums per molecule, showing an exceptionally high charge capacity (343 mAh/g). the complete finding of my research work will be presented.</p> <p>&nbsp;</p> saisrinu yarramsetti Copyright (c) 2021 saisrinu yarramsetti 2021-10-08 2021-10-08 1 01 HYBRID CONVERTER FOR STANDALONE SOLAR PHOTOVOLTAIC SYSTEM https://spast.org/techrep/article/view/161 <p>Renewable energy sources are ever blooming sources for the energy generation in the world. Some of the regions in our country can manage extremely mere power production with this renewable sources. In the world energy production, renewable energy installed capacity occupies 586.42 GW. In that India it has been 35.06 GW. The investments on solar energy generation are continuously increasingly irrespective of the installation and maintenance cost. The energy generated from the solar is enhanced by using the DC-to-DC Converters and DC to AC Converters. Most of the grid tied system are running with the DC-to-DC converters and DC to AC Converters. The two stages of power conversions need to be carried out in all the system. This paper focusses on hybrid converter for both AC and DC Conversion which enhances the system efficiency much higher and reduces the cost for including separate Inverter for most of the applications. The DC converter voltage, current, voltage gain and output voltage, output current of the inverter are compared in this paper.</p> Rubia Gandhi R R Copyright (c) 2021 Rubia Gandhi R R 2021-09-08 2021-09-08 1 01 Ab initio calculations on Zn(O,S) buffer layer for cost effective photovoltaics https://spast.org/techrep/article/view/1654 <p>Zinc oxysulphide (Zn(O,S) is a promising material for replacing the Cd-free buffer layer in thin film photovoltaic (PV) cell. This material has sparked a lot of interest because of its wide bandgap tunability by varying the sulphur and oxygen concentrations [1-2]. Furthermore, at higher sulphur concentrations (S &gt; 70%), Zn(O,S) has an ideal conduction band offset with Cu2O which is an earth abundant and environment friendly absorber layer [3]. But, there are only limited studies which explain the optoelectronic properties of Zn(O,S) system in terms of its electronic density of states and band structure. Therefore in the present work, we have studied the optoelectronic properties of Zn(O,S) for O rich (hexagonal wurtzite phase) as well as S rich (cubic zinc blende phase) conditions through ab initio calculations. The density functional theory calculations were performed using the plane wave self-consistent field (PWSCF) approach as implemented in the Quantum ESPRESSO package [4]. The interactions between the core electrons and the valence electrons were represented by the projector augmented wave (PAW) method. Generalized gradient approximation (GGA) as parametrized by Perdew-Burke-Ernzerhof (PBE) was used to treat the electron exchange and correlation terms. For the hexagonal wurtzite structure, the 2 \times 2 \times 2 supercell of ZnO containing 32 atoms was created in which S was introduced as the anionic substitutional impurity (Fig. 1a). On the other hand, the 2 \times 2 \times 2 supercell of zinc blende ZnS contains 64 atoms in which O was introduced as the anionic substitutional impurity. The undoped as well as the doped structures were fully relaxed in terms of their atomic coordinates and cell dimensions. The total energy during was converged to within 10-8 Ry. The semi-empirical DFT+U (Hubbard-U correction) calculations were performed to take into account the correlation effects in ZnO and ZnS. Fig. 1a, b shows the optimized crystal structure with the calculated electronic band structure for S doped ZnO system. For pure ZnO, the lattice parameters were found to be a = b = 3.2786 Å and c = 5.2941 Å which is in accordance with the reported values in the literature. S doping resulted in an increase in the lattice volume with the corresponding lattice parameters as a = b = 3.3121 Å and c = 5.3547 Å. The electronic band structure clearly indicates the semiconducting nature for ZnO as well as S doped ZnO with a direct band gap at the -point. The direct band gap was found to be slightly increased from 3.06 eV to 3.23 eV with S incorporation into the hexagonal lattice. From the band structure, substitutional S was found to be acting as a donor with the corresponding defect levels lying below the Fermi level. Similarly, the electronic density of states (DOS) also reveals the presence of S related impurity states at the forbidden region. Based on the ab initio calculations, the proposed Cu2O based PV cell with Cu2O/Zn(O,S)/Al:ZnO device structure was simulated under AM1.5 conditions by using the SCAPS-1D software [5]. The efficiency (η), fill factor (FF), short-circuit current density (JSC), and open-circuit voltage (VOC) were calculated at various thicknesses of the Zn(O,S) buffer layer. Besides this, we also examined the quantum efficiency for the proposed device. The ab initio calculation as well as the device simulation performed in the present study will help the experimentalists to design the cost-effective Cu2O based PV cell with enhanced photoconversion efficiency.</p> <p><img src="https://spast.org/public/site/images/lakshmanan/mceclip0.png"></p> <p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; (a)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;(b)</p> <p><strong>Fig.1.</strong> (a) Optimized crystal structure for S doped ZnO and (b) Electronic band structure for S doped ZnO across the high symmetry <em>k</em>-points</p> Lakshmanan A Zachariah C Alex S. R. Meher Copyright (c) 2021 Lakshmanan A, Zachariah C Alex, S. R. Meher 2021-10-08 2021-10-08 1 01 Cost Optimization and Emission control of a Grid connected Hybrid PV-Wind system for a Health Care Centre in India https://spast.org/techrep/article/view/1738 <p>Due attention is needed for energy demand in health care centers as energy requirement for average Energy Use Intensity (EUI) is huge. It is to be noted that EUI is the energy per square foot per year. The technology advancement result in sophisticated and inevitable equipment, increases the energy consumption of the health care centers. The maintenance of these equipment and increase in the patient to doctor ratio are also one of the main reason which affects the energy consumption. India is found to be the fourth largest greenhouse gasses emitter. As a result, India is much affected by the change in climatic conditions. Therefore the obligatory situation is arised in India to reduce the global warming which can be possible with the penetration of renewable energy based electricity generation. Our major objective is to produce the electrical energy with the optimized PV- wind system and to avoid the global warming with the optimized energy generation technology.</p> <p>The novelty in the work is to generate the electricity with Hybrid pv-wind&nbsp;system for a health care centre in India, and to payback the excess energy produced to the electricity board through grid system. &nbsp;&nbsp;</p> <p>A health care center which uses 160kWh/day of electrical load and deferrable load of 10kWh/d is taken for analysis. 200 kW of PV and 100 kW of wind generation capacity&nbsp;are proposed for generating power. The monthly average wind speed profile and solar profile is downloaded from NASA Prediction of Worldwide Energy Resource database. 300kW converter is used, with the mean output of 38.8W capacity is used in the proposed system for power conversion.An idealized battery storage system of 48V is introduced with the capacity of 139kWh and round trip efficiency of 64%.</p> <p>Homerpro 3.11.2 is used to obtain and analyse the optimization result. The analysis gives best solution for cost summary, economic comparison in using various resources. This microgrid requires 1938 kWh/day and has a peak of 305 kW. In the proposed system, the energy demand, energy selling and cost analysis is done. The energy demand of the health care system is estimated and the remaining energy produced is sold back to the grid. Grid power is connected to the system with simple rates of grid power rate and sell back rates.</p> <p>From the Homer Analysis, the Net Present Value, total Annualized Cost, simple payback, Return on Investment (ROI), the Internal Rate of Return (IRR) and annual savings are estimated for the proposed system. It is estimated that our investment has a payback of 1.33 years and an IRR of 75.3%. The annual energy purchased from the grid is 6,639 kWh and the annual energy sold to the grid is 643,549 kWh.</p> <p>Along with the cost analysis, &nbsp;the emission of gases like carbon dioxide, carbon monoxide, unburned hydrocarbons, particulate matter, sulfur dioxide and nitrogen oxides are also calculated for the proposed system. The analysed result gives null result for the emission of green house gases and the proposed system becomes environmental friendly system in reducing the global warming. Also cost analysis of the proposed system proves the annual savings in regards with the energy consumption.</p> Abitha Memala W Bhuvaneswari C Susitra D Copyright (c) 2021 Abitha Memala W, Bhuvaneswari C, Susitra D 2021-10-08 2021-10-08 1 01 Graphitic Carbon Nitride/Copper Sulfide Nanocomposite Heat Localization Material for Solar Steam Generation https://spast.org/techrep/article/view/352 <p>One of the most pressing challenges currently being faced by humanity is the threat of water shortages and freshwater scarcity, without which we could face a complete destabilization of human civilization. At present 1.1 billion people suffer from freshwater scarcity, and this figure is expected to rise to 40% of the world’s population by 2050 [1–3]. Furthermore, the demand for freshwater from manufacturing and household is expected to rise by 400% and 130%, respectively. Solar steam generation (SSG) is a technology that could be used to remediate the current situation by utilizing solar energy to heat water to its latent heat of vaporization in order to produce water vapor/steam, which would then condense and be collected as freshwater [6,7]. However, there are significant limitations to this approach: high cost associated with complex geometrical design and lenses needed for appropriate magnification of sunlight, exotic coatings to increase solar absorptivity, and most importantly the non-localized warming of the water causing the thermal energy to dissipate into the bulk of the fluid [8–12]. Thus, this technology needs to be improved in order to serve as a viable solution remediation for the freshwater crisis. One such advancement that addresses the aforementioned shortcomings is interfacial solar steam generation. In this approach, a highly absorptive heat localization structure is floated at the surface of the fluid in order to intensely absorb solar radiation and translate it to the thermal energy of a thin film of water adsorbed within the heat localization structure. A heat localization material (HLM) is constituted of a strong visible light and NIR absorber layer, an optional support layer to improve the mechanical properties of the absorber, and a substrate which is typically needed for thermal isolation of the absorber form the fluid and for buoyancy. Such an approach is not reliant on expensive absorption strategies such as lenses or coatings, and most importantly, localizes the heating of the water only at the surface; thereby resulting in intense heating and &nbsp;the rapid generation of water vapor/steam and no loss to the bulk of the fluid and the external environment [13–18].&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p>In this study the absorber layer is a novel nanocomposite of the layered graphitic carbon nitride (g-CN) and copper sulphide nanoparticles. A support layer of a porous mixed cellulose ester membrane, and a substrate of extruded polystyrene foam wrapped in airlaid paper. <br>g-CN, apart from being an inherent visible light absorber, will also allow for superior water transport and subsequent heat transfer to water due to its hydrophilic nature. Covellite nanoparticles display intense plasmonic absorption at the NIR region resulting in intense heating. Moreover, both copper sulfide and graphitic carbon nitride are non-toxic which is critical as the desired application solar desalination [19–21].</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>The practical suitability of the HLM was then tested in a solar still and compared to the performance four identical solar stills. This system had a transmittance in the range of 0 to 5, a water evaporation rate of 2.6 kg/m<sup>2</sup>, and an evaporation rate that is 1.5 times greater than that of pure water. The HLM modified solar still was the most effective in comparison to the control solar stills as it had the greatest yield of freshwater as well the highest quality of freshwater. Therefore, this literary work further validates the effectiveness of heat localization technology in providing a practical, productive and eco-friendly solution to the freshwater crisis, while introducing a new material with this functionality. It is a step towards a brighter future. &nbsp;</p> Joshua Fernandes Sujith Kalluri Asha Madhavan Copyright (c) 2021 Joshua , Sujith, Asha Madhavan 2021-09-14 2021-09-14 1 01 A facile synthesis of high performing MnxOy-rGO hybrid composite for potential supercapacitor application https://spast.org/techrep/article/view/2695 <p>In 2015, the United Nations (UN) has proposed a roadmap to achieve clean, cheap, and renewable energy in their sustainable development goals. As well as the modern technological advancement with zero-emission has been emphasized to upgrade the quality of lifestyles especially in developed countries [1]. As a consequence of the necessity, nowadays smart and heavy-duty electric vehicles have been introduced in front of modern society. Those electrical vehicles are accelerated by a heavy-duty electrical energy storage device (hybrid batteries, supercapacitors) which can be easily changed within a short period and supply required power with efficient mileage too [2].&nbsp; In the context of energy storage, supercapacitors especially electric double-layer capacitors (EDLC) are good owing to their robust lifetime, longer cycle life, rapid charging-discharging, low maintenance cost, and high power energy storage for multipurpose applications [3].&nbsp; Usually, carbon-based materials <em>viz.</em> graphene, reduced graphene oxide (rGO), CNT, biomass-derived porous carbon materials, etc. are the most popular candidates of EDLC [4]. Among them, rGO is special for their excellent electrochemical performance attributed to their morphological excellence including the expanded d-spacing and abundant surface area. But their highly agglomerate properties reduce their performance (conductivity, accessible surface area) thus limits their applications [5].</p> <p>To address this issue, rGO can be synthesized by mixing with other transitional metal or metal oxide which will contribute to the expansion of the rGO layer, and enhance the supercapacitor performance by induces pseudocapacitance thus increasing the charging-discharging rate [6]. &nbsp;Due to the various oxidation states and high theoretical capacitance (1370 Fg<sup>-1</sup>) manganese oxides are highly recommended as a high-performance supercapacitor electrode material [7].&nbsp; Moreover, the natural abundance of manganese is greater than most of the other transitional metals. Hence, the incorporation of Mn<sub>x</sub>O<sub>y </sub>also attributes to rGO electrode performance by enhancing the surface area, interlayer distance, and charge transfer rate due to the fast-reversible redox reaction [8]. The total electrochemical performance of the Mn<sub>x</sub>O<sub>y</sub>-rGO electrode highly depends on the morphology and amount of incorporated Mn<sub>x</sub>O<sub>y</sub> [9]. Interestingly, the presence of high content of Mn<sub>x</sub>O<sub>y</sub> results in poor performance of the rGO-Mn<sub>x</sub>O<sub>y</sub> electrode. This might be occurred because of the higher agglomeration of Mn<sub>x</sub>O<sub>y</sub> in and on between the rGO surface and blocking of rGO pores. As a result, the charge transfer resistance of the electrode material increases. So, it is very crucial to optimize the amount of Mn<sub>x</sub>O<sub>y</sub> during the preparation of the Mn<sub>x</sub>O<sub>y</sub>-rGO composite during the synthesis. In this work, the rGO-Mn<sub>x</sub>O<sub>y</sub> composite was synthesized in a facile way by optimizing the amount of KMnO<sub>4</sub>. In brief, different concentration of KMnO<sub>4</sub> was mixed with 0.2 g of GO suspension under vigorous stirring and sonication. 5 mL of glycerin was further added to form precursors for the preparation of Mn<sub>x</sub>O<sub>y</sub>-rGO. Finally, the mixture was reduced by a one-step hydrothermal reduction process (180°C for 24 h) followed by washing and drying. The electrochemical capacitance performance of all compositions was evaluated using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) in a two-electrode system with 0.5 M Na<sub>2</sub>SO<sub>4</sub> aqueous electrolyte solution. The maximum specific capacitance was found at 280 Fg<sup>-1</sup> at 1 Ag<sup>-1</sup> current density for the rGO-Mn<sub>x</sub>O<sub>y</sub> composite at the concentration of 0.05mM KMnO<sub>4</sub>. The summarized electrochemical data are represented in Table 1. <sub>&nbsp;</sub>The total work is expected to contribute to the next generation of hybrid supercapacitor applications.</p> <p><strong>Table 1.</strong></p> <table> <tbody> <tr> <td width="47"> <p><strong>No.</strong></p> </td> <td width="71"> <p><strong>Conc. of KMnO<sub>4</sub></strong></p> </td> <td width="112"> <p><strong>Electrolyte</strong></p> </td> <td width="91"> <p><strong>Potential &nbsp;window, (V)</strong></p> </td> <td width="118"> <p><strong>Specific capacitance, C<sub>sp</sub>(Fg<sup>-1</sup>)</strong></p> </td> <td width="82"> <p><strong>Energy density, E</strong></p> <p><strong>(Whkg<sup>-1</sup>)</strong></p> </td> <td width="81"> <p><strong>Power density,</strong><strong>P</strong></p> <p><strong>(kWkg<sup>-1</sup>)</strong></p> </td> </tr> <tr> <td width="47"> <p>1.&nbsp;&nbsp;&nbsp; &nbsp;</p> </td> <td width="71"> <p>0.5 mM</p> </td> <td width="112"> <p>Na<sub>2</sub>SO<sub>4</sub></p> </td> <td width="91"> <p>1.0</p> </td> <td width="118"> <p>280</p> </td> <td width="82"> <p>9.72</p> </td> <td width="81"> <p>250.0</p> </td> </tr> <tr> <td width="47"> <p>2.&nbsp;&nbsp;&nbsp; &nbsp;</p> </td> <td width="71"> <p>0.5 M</p> </td> <td width="112"> <p>Na<sub>2</sub>SO<sub>4</sub></p> </td> <td width="91"> <p>1.0</p> </td> <td width="118"> <p>100</p> </td> <td width="82"> <p>3.47</p> </td> <td width="81"> <p>250.0</p> </td> </tr> </tbody> </table> Sanjida Afrin Ragib Shakil Yeasin Arafat Tarek Shakhawat Hossain Firoz Copyright (c) 2021 Sanjida Afrin, Ragib Shakil, Yeasin Arafat Tarek, Shakhawat Hossain Firoz 2021-10-21 2021-10-21 1 01 Modelling and Analysis of Wearable Thermoelectric Device (WTED) and its Mechanical behaviours https://spast.org/techrep/article/view/2082 <p>Supplying sustainable power to portable devices requires a promising energy harvesting technology. The thermoelectric effect is an assuring technique to harvest energy from waste heat. This paper presents the modeling of wearable Thermoelectric device (WTED) with different device component variations such as several legs (2 and 12 leg configuration), the material of electrodes (Copper electrode vs. Silver electrode), filler material of PDMS for device flexibility, and solder paste of SAC305 at the range of temperature gradient (00 to450C ) and loads. All these former components optimization is done to ensure the theoretical maximum electric output, the stress distribution, and deformation on mechanical load till the elastic limit of the device. This thermoelectric device has used Bismuth Antimony Telluride (Bi<sub>0.5</sub>Sb<sub>1.5</sub>Te<sub>3</sub> as p-type) and Bismuth Selenium Telluride (Bi<sub>2</sub>Se<sub>0.5</sub>Te<sub> 2.5</sub> as n-type). The result shows that the device's open-circuit output electric potential with two legs at ∆T = 100C was 4.4mV, and that of 12 leg device shows the output as 24.9mV. The result promises high performance of TEG in harvesting human body temperature into small-scale electronic chips and device's power source.</p> Suhasini Sathiyamoorthy Pandiyarasan Veluswamy Copyright (c) 2021 Suhasini Sathiyamoorthy, Pandiyarasan Veluswamy 2021-10-08 2021-10-08 1 01 Modelling the SEI-Formation on Electrodes in LiFe0,99Gd0,01PO4/C Batteries https://spast.org/techrep/article/view/1634 <p>An advanced model describing the capacity losses of LiFe<sub>0,99</sub>Gd<sub>0,01</sub>PO<sub>4</sub>/C batteries under synthesis conditions is proposed in this work. These capacity losses are attributed to the growth of a solid electrolyte interface (SEI) of LiPF<sub>6</sub> on the surface of lithium metal (Li) in the negative electrode. This model considers the existence of an inner and outer SEI layers. The rate determining step is considered by electron tunneling through the inner SEI layer. It is found that the inner SEI layer grows much slower than the outer SEI layer. Another contribution to the degradation process is the exfoliation of SEI near the edges of graphite particles during discharging and the formation of newly induced SEI by the volumetric changes during the subsequent charging. This model has been validated by storage and cycling experiments. The simulation results then show that the capacity losses are dependent on the state of charge (SoC), the storage time, cycle number and graphite particle size. The model can be used to predict both the calendar and cycling life of the Li-ion batteries.</p> Anggi Suprabawati Iman Rahayu Atiek Rostika Noviyanti Anni Anggraeni Heri Jodi Copyright (c) 2021 Anggi Suprabawati, Iman Rahayu, Atiek Rostika Noviyanti, Anni Anggraeni, Heri Jodi 2021-10-08 2021-10-08 1 01 A Development of High-Capacity Organosulfur Cathodes for Li-ion Batteries – A DFT Study https://spast.org/techrep/article/view/371 <p>Lithium-ion batteries have dominated the portable electronics market and show great promise in large-scale applications such as smart grids and EVs. To date, commercial metal oxide cathodes like LiCoO<sub>2</sub>, LiFePO<sub>4</sub>, or LiNi<sub>x</sub>Mn<sub>y</sub>Co<sub>Z</sub>O<sub>2</sub>, are mainly used. However, ores and the resources of these metal oxides are very limited [1-3]. Several research groups focused on searching for a new generation of rechargeable lithium battery technologies with low cost using more environmentally friendly and naturally abundant materials. The advantages of organic materials are discussed in three aspects, compared with inorganic cathode materials [4]. Firstly, organic compounds consisting of a lightweight elements such as C, H, O, N, and S, which leads to low cost and high gravimetric energy density. Secondly, these materials are structurally flexible and stable. In contrast, inorganic materials undergo structural changes during dis/charging, leading to diffusion of alkali ions from the structure is very difficult. Thirdly, organic compounds can provide multiple lithiation sites leading to high energy densities and tune the redox properties by different substituents [5].</p> <p>The current study is focused on <strong><em>organo sulphur</em></strong> compounds as they possess high theoretical capacities due to multi-electron reactions of S-S bonds [6-7]. In the present study, DFT methods are applied to investigate the redox properties of several organosulfur organic compounds, namely benznesulphur, napthasulphur, anthrasulphur, tetrasulphur, petnasulphur, sumanenesulphur, and coronenesulphur. The computed redox properties are described based on the position of sulphur atoms on aromatic ring structures. Also, we understood the redox values are affecting as increasing the number of reacted lithiums. This investigation reveals an essential finding of mono sulphur, disulphide bond containing organic cathodes and their redox potential differences. Also, we calculated the theoretical performance of the highest redox potential exhibiting molecules. Finally, we found that pentacene sulfur has the highest redox potential and theoretical performance. It can take up to eight lithium per molecule, showing an exceptionally high charge capacity (409 mAhg<sup>-1</sup>). The lithiation mechanism of the Pentacene molecule is given in Figure (B), where the electron from Li-metal is added to the molecule followed by Li<sup>+</sup>-ion. A total of eight lithium reacted with the molecules showing a theoretical capacity of ~400 mAh/g. The complete findings will be presented.</p> saisrinu yarramsetti Copyright (c) 2021 saisrinu yarramsetti 2021-09-14 2021-09-14 1 01 Polypyrrole/MoS2 Nanocomposite for Flexible Supercapacitor Applications https://spast.org/techrep/article/view/1196 <p>A new kind of chitosan-polypyrrole nanotubes/molybdenum disulphide (CS-PNTs/MoS<sub>2</sub>) nanocomposite is fabricated for the first time&nbsp;<em>via</em> a facile two-step <em>in-situ</em> chemical polymerization and hydrothermal method and successfully applied in charge storage flexible supercapacitor (SC) devices. The CS-PNTs/MoS<sub>2 </sub>nanocomposite makes up a good SC electrode material by&nbsp;inheriting the facts of good electrical conductivity of MoS<sub>2</sub>&nbsp;and enhanced pseudocapacitive activity of polypyrrole nanotubes (PNTs). The incorporation of chitosan (CS) increases the cyclic stability of CS-PNT/MoS<sub>2</sub> nanocomposite by reducing the aggregation of MoS<sub>2</sub> Quantum dots and enhancing the surface area and porous structure of the nanocomposite which facilitates the diffusion of solvent and faradic process.&nbsp;The CS-PNTs/MoS<sub>2 </sub>nanocomposite exhibits a highest specific capacity (C<sub>sp</sub>) of 759 C/g and solid state flexible symmetric supercapacitor (SSC) was assembled using CS-PNTs/MoS<sub>2</sub>&nbsp;achieved a high-power density of 7680 W kg<sup>-1</sup>&nbsp;at an energy density of 32.12 Wh kg<sup>-1 </sup>and also good cyclic stability with capacity retention of 91.2% after 10,000 cycles at 10 A/g. Remarkably, the SSC device featured enhanced flexibility and stability and can sustain up to 97% of its initial capacity under various bending positions, clearly suggesting that the fabricated solid-state SSC device is exceptionally flexible and can be deformed without distracting its structural integrity and energy storage ability. These findings suggest that CS-PNTs/MoS<sub>2</sub>&nbsp;represents a promising electrode material for flexible supercapacitors.</p> Dr. VIJETH Copyright (c) 2021 Dr. VIJETH 2021-09-24 2021-09-24 1 01 Review of Real Time Implementation of State of Health of a Li-Ion Battery https://spast.org/techrep/article/view/1441 <p>Nowadays usages of electric vehicles are increased due to abnormal price hike of petrol, pollution-free driving and less noise, lightweight. The battery’s SoH provides important details to the BMS to decide the battery life conditions. The function of BMS is to provide safe and efficient operating conditions to the battery. BMS protects the battery from over-voltage, under-voltage, over-charge and over-discharge, over-temperature, and under temperature. Due to ageing problem, the internal resistance is increased hence the retention capacity of the battery is reduced, the internal resistance is inversely proportional to the battery capacity. The SoH cannot be measured directly, it is estimated from the internal resistance and the capacity of the battery. Early prognosis of Battery gives the replacement of the battery and avoid any accident because of battery malfunction. The fast and accurate method of estimating the State of Health is remaining challenge in the area of battery’s research. This paper provides the various estimating algorithms, implementation methods and their advantages and disadvantages. It provides overall estimation of SoH techniques which were used in literature survey.</p> Murugan Veerasingh Copyright (c) 2021 Murugan Veerasingh 2021-10-07 2021-10-07 1 01 Facile Synthesis of Boron doped NiCu for efficient methanol oxidation: Selectivity towards value-added fomate formation https://spast.org/techrep/article/view/711 <p>The impending nature of the fossils fuel and to mitigate the CO<sub>2</sub> content, the search for clean renewable energy sources has become imperative. In order to fulfil the energy demand of growing population, considerable research work has been focused on methanol fuel cells. However, high cost of noble metals and occurrence of CO poising hinders the practical application[1-2]. In order to replace the noble metals, design and development of non-noble metal-based electrocatalyst has gained numerous attentions owing to their high mobility, low working temperature, and low emission of greenhouse gases. Among different non noble metals, spinel structure of nickel copper oxide has been considered as a good catalyst for methanol oxidation reaction due to its partially filled d-valence orbitals, which induces spin and orbital degrees of freedom, resulting in better electrochemical activity. Nevertheless, the oxidation of methanol at nickel copper electrocatalyst still suffers due to its low porous structure and electrical conductivity[3]. In order to alleviate the above issues, researchers adopted different strategies, such as incorporation of polymer, carbon based materials, doping of heteroatom, etc to non noble metals. Among them, heteroatom doping namely boron has gained numerous attentions owing to its tunable electronic structure of host electrocatalysts, which helps in absorbing more methanol effectively. Moreover, simple boron combustion and calcination technique was adopted to synthesize nickel copper oxide and boron doped nickel copper oxide. Interestingly unlike other noble metals, boron doped nickel copper oxide yields formate as primary intermediate[4]. It is worth noting that, this formate/formic acid results as a partial oxidation product in non noble metal based methanol oxidation reaction and it is an important industrial intermediate that can be used in diverse chemical industry fields, such as rubber, pharmaceutical, dye, direct formate fuel cell and hydrogen storage. However, traditional industrial formic acid production usually involves complicated multi-step processes and requires large amounts of energy consumption, resulting in its high cost. Considering the industrial price, a ton of methanol might be sold at about $350, which can be useful in converting electricity at low cost as compared with other techniques such as battery, tidal plant, etc. Moreover, the byproduct can be used effectively in various industries, which also reduces the cost and preserve the environment. Hence, generation of electricity along with production of value-added products, can resolve both energy and environmental crisis. In this present work, we have synthesized highly electroactive boron doped nickel copper oxide for efficient methanol oxidation reaction[5]. The prepared electrocatalyst was characterized with various spectroscopy studies such as XRD, FT-IR and XPS spectroscopy studies. The effectiveness towards methanol oxidation reaction was studied by employing cyclic voltammeter and chronoamperometry studies. This work opens up a new insight for the designing and fabricating non noble metal based methanol oxidation reaction.&nbsp;</p> Naveen Kumar T. R Copyright (c) 2021 Naveen Kumar T. R 2021-09-16 2021-09-16 1 01 Performance studies of biomass derived RHAC and MgO2 Nanocomposite electrode material for supercapacitor applications. https://spast.org/techrep/article/view/752 <p>Sodium-ion batteries, lithium-sulfur batteries, and supercapacitors are examples of electrochemical energy storage technologies, have shown great promise and received a lot of research attention among the many energy storage systems [1]. Because of its ability to store data quickly, SCs have attracted more interest than batteries, a Supercapacitor with the same weight as a battery can hold more power and enhanced cyclic stability. Aside from low energy density, new advances in SC electrolytes and electrode materials have the potential to bridge the gap between fuel cells and batteries and conventional electrolytic-capacitor technology [2]. The material used to build a supercapacitor's electrodes and the electrolyte that delivers the greatest results for each electrode define the supercapacitor's efficiency. As a result, the material of the electrode becomes crucial. Two compounds that have attracted interest for supercapacitor applications are transition metal oxides and carbon-based materials. Carbonaceous compounds, as compared to metal oxides, have the highest surface area. Porosity, chemical and thermal stability, surface area, and packing density are all characteristics of activated carbons. Activated carbons for supercapacitors are mainly made from renewable materials, such as biowaste, sawdust, neem leaves, coconut shells, bamboo, and weeds.</p> <p>The electrode materials for supercapacitors based on biomass-produced Rice Husk Activated Carbon (RHAC) and RHAC + 50%MgO<sub>2 </sub>nanocomposite are compared in this article. The crystallinity, structural morphology, and crystalline size of the particles were determined using microstructural and electrochemical characterization. Scanning Electron Microscope and X-Ray Diffraction techniques were used to determine the surface morphology and crystallinity of the materials. The XRD results reveal that RHAC which has broad peaks indicates amorphous nature whereas RHAC+50%MgO<sub>2 </sub>nanocomposite which has sharp peaks exhibits crystalline nature.The theRHAC+50%MgO2 nanocomposite electrode exhibits a specific capacitance of 220.52 F/g however RHAC electrode exhibited only 162.91 F/g at a scan rate of 2mV/s by Cyclic Voltammetry in 1 M KOH electrolyte. After 2500 cycles of Galvanic charge-discharge, it was discovered that RHAC+50%MgO<sub>2</sub> nanocomposite has capacitance retention of 76.71% and RHAC has capacitance retention of 80.49%.</p> Ajay K M Copyright (c) 2021 Ajay K M 2021-09-19 2021-09-19 1 01 Enhanced efficiency in electrodeposited cuprous oxide thin film homojunction solar cells https://spast.org/techrep/article/view/2377 <p><strong>Abstract </strong></p> <p>Cuprous oxide (Cu<sub>2</sub>O) is a lattice defect type semiconductor material owing to important optoelectronic properties. Fabrication of Cu<sub>2</sub>O thin film solar cells using electrodeposition technique is being investigated over years to introduce cheap and environmentally friendly solar cells to PV market [1-3]. Nevertheless, inherent electrochemical properties of Cu<sub>2</sub>O is observed to be the reason for the low short-circuit current density (J<sub>SC</sub>) values reported in the literature of Cu<sub>2</sub>O based solar cells [1,3-4]. However, surface modification methods such as annealing and sulphidation have proven the capability of improving the quality of Cu<sub>2</sub>O by controlling the surface properties [2,5]. This has led to the improved J<sub>SC </sub>values close enough to the maximum theoretical limit of 14 mA cm<sup>-2</sup>. However, the poor fill factor (FF) and open-circuit voltage (V<sub>OC</sub>) values still dwindle the efficiency ( ) of Cu<sub>2</sub>O solar cells. In this study, we have investigated the possibility of improving the FF and V<sub>OC</sub> values of Cu<sub>2</sub>O solar cells while preserving the resulted high J<sub>SC</sub> values. &nbsp;</p> <p>It is well-known that Cu<sub>2</sub>O thin films can be grown to exhibit n- or p-type conductivities depending on the growth conditions of the Cu<sub>2</sub>O film deposition baths as well as annealing conditions [6,7]. Indeed, tuning the ion concentration and pH of the Cu<sub>2</sub>O film deposition bath is capable of changing the stoichiometry of the Cu<sub>2</sub>O so that the Fermi level in Cu<sub>2</sub>O can be altered to form n- or p-type Cu<sub>2</sub>O films. Of course, the open-circuit voltage value of a p-n junction solar cell depends on the positions of its n- and p-type materials’ Fermi levels. When the Fermi level of n-type material is closer to the conduction band and that of p-type is closer to the valence band it will lead to produce high V<sub>OC</sub> values &nbsp;[8].</p> <p>In this study, we have examined the feasibility of improving the V<sub>OC</sub> value of homojunction Cu<sub>2</sub>O solar cell by varying the ion concentrations of p-Cu<sub>2</sub>O film deposition bath. Initially, &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;n-Cu<sub>2</sub>O thin film was potentiostatically electrodeposited on the titanium substrate using an acetate bath consisting of&nbsp; 0.1 M sodium acetate and &nbsp;0.01 M cupric acetate at a pH value of 6.1, a deposition potential of -200 mV vs. Ag/AgCl and a bath temperature of 55 . Films were annealed at 100 &nbsp;for 24 hours and 175 &nbsp;for 30 minutes. Subsequently, p-Cu<sub>2</sub>O thin film layer was potentiostatically electrodeposited on this Ti/n-Cu<sub>2</sub>O electrode using a lactate bath at a pH value of 13.0, a deposition potential of -450 mV vs. Ag/AgCl and a bath temperature of 60 . Then, this Cu<sub>2</sub>O bi-layer was exposed to 20% ammonium sulphide vapour for 8s. Finally, a thin layer of gold is sputtered on this as a grid of gold to form the front contacts. The lactate bath, which is consisted of 0.4 M copper sulphate pentahydrate, 2.51 M lactic &nbsp;acid, 4 M sodium hydroxide ion concentrations has produced the best solar cell of J<sub>SC</sub> = 12.95 mA cm<sup>-2</sup>, V<sub>OC</sub> = 445 mV, FF = 39.5% and &nbsp;= 2.28%. The current density-voltage (J-V) characteristic curve for the best solar cell is illustrated in fig. 1. According to the figure, it is notable that the FF and the V<sub>OC</sub> values have been improved significantly while the J<sub>SC</sub> value is high as 12.95 mA cm<sup>-2</sup>. The efficiency reported here is very significant in respect of Cu<sub>2</sub>O homojunction solar cells because it clearly demonstrates the possibility of adapting the low cost Cu<sub>2</sub>O material and fabrication methods in achieving a commercially viable solar cell.</p> <p><strong>Acknowledgement:</strong> Financial support of the National Research Council of Sri Lanka (NRC 19-051) is gratefully acknowledged.</p> RP Wijesundera S.A.A.B. Thejasiri F.S.B. Kafi W. Siripala Copyright (c) 2021 RP Wijesundera, S.A.A.B. Thejasiri, F.S.B. Kafi, W. Siripala 2021-10-09 2021-10-09 1 01 HYDROGEN IMPERMEABLE MATERIALS FOR EFFICIENT HYDROGEN STORAGE https://spast.org/techrep/article/view/314 <p>The world’s fossil fuel resources are limited and are getting depleted rapidly. Most of the current energy demands are fulfilled by fossil fuels and the related implications due to the rise in greenhouse gas emissions is a major concern [1]. Hence, the use of renewable energy sources should be encouraged. Hydrogen is an important alternative to other energy sources which is clean and abundant [2]. Hydrogen is used in many industries starting from refineries to chemicals. The global demand for hydrogen has escalated over the decades, from around 20MT (Million Tons) in 1975 to around 70MT in 2018. Yet, most of the hydrogen production is through fossil fuels and its costs range from 1 to 3 USD per kg. This must change because an energy transition is taking place to reduce the emission of greenhouse gases and to combat climate change. Recent advancement in this field includes the production of green hydrogen, a new ally for a zero-carbon future [3]. The development of efficient hydrogen storage systems plays an important role in the adaptation of hydrogen as an alternate fuel. However, hydrogen is considerably difficult to handle given its small size, high volatility, flammability, lowest energy density (per unit volume), and the fact that it travels with the velocity of sound. These properties of hydrogen lead to its permeation through several materials that are impermeable to other gases. This permeation and trapping lead to the generation and propagation of cracks in carbonaceous materials which is termed hydrogen embrittlement. It also results in the degradation of mechanical properties such as ductility, tensile strength, fatigue strength, and fracture toughness of the materials. This ushers the search for hydrogen impermeable materials. &nbsp;</p> <p>Processes like cathodic charging, electroplating, and welding allow hydrogen to enter metals and alloys [4]. High strength materials such as high strength steels, high Manganese steel, aluminum, titanium, and magnesium alloys of steel are most vulnerable to hydrogen embrittlement. The factors that affect hydrogen embrittlement include gaseous and dissolved sources of hydrogen, residual or applied stress, material susceptibility, exposure time, type and production method of the alloy, number of discontinuities, heat treatment method, etc. The prevention of embrittlement focuses on two approaches, one being surface treatment methods (such as surface coatings, surface modification) and the other being the modification of the microstructure of materials, which includes the addition or elimination of suitable alloy elements [5]. Alternative options include the use of lower strength steel, low hydrogen plating, and minimization of applied and residual stress.</p> <p>Hydrogen storage is very important when it comes to the usage of hydrogen on a large scale. This could either be for stationary or for mobile applications. The stationary applications include storage on-site at points of use or production and power generators. The mobile applications are hydrogen transportation and vehicle fuels. Hydrogen storage is currently done in different ways such as a compressed gas using metallic heavy steel containers, steel vessels with glass fiber composite overwraps, full composite wrap with metal lining, and fully composite storage systems. However, steels are heavy and occupy a lot of space, whereas composites are expensive [2]. Also, the durability of the current materials used is not up to the mark. Therefore, lightweight, compact, and durable materials must be made to increase the lifespan of the hydrogen storage systems. The energy efficiency must be increased as the energy used to get hydrogen in and out is more than that of the fuel itself. The low density of hydrogen even at extreme pressures and temperatures results in a low energy per unit volume. So, storage methods having more potential for greater energy density (per unit volume) must be developed. Other challenges are long refueling times and a lack of analysis of the full life-cycle cost and efficiency for current storage systems. Overcoming these challenges can help increase vehicle range and bring down the overall cost of storage if hydrogen impermeable materials with better properties are created. This is ultimately expected to facilitate the desired shift to green hydrogen technology.</p> Ujwal Shreenag Meda Nidhi Bhat Chitra Agrawal Copyright (c) 2021 Ujwal Shreenag Meda, Nidhi Bhat, Chitra Agrawal 2021-09-14 2021-09-14 1 01 Lithium-ion Battery Model Parameters Estimation Using Modified Grey Wolf Optimization for E-mobility Applications https://spast.org/techrep/article/view/502 <p>Accurate estimation of battery internal model parameters and consequently state of charge (SOC) prediction is crucial in any battery powered systems. Especially, it is the fundamental need in Electric Vehicles (EVs), smart grids, and energy storage systems. The accuracy in Identification of model parameters will affect the Battery Management System (BMS), battery safety, characteristics, and performance [1]. To estimate the parameters accurately and easily, we require effective, simple, and robust parameters estimation algorithms. In this abstract, we have proposed a new method for parameters estimation using the modified Grey Wolf Optimization (GWO) for Lithium-ion Batteries (LIBs) in EV applications. Second order RC equivalent circuit Model is considered for NMC battery. The parameters estimation and non-linear relation of OCV-SOC are obtained from the experimental data as shown in Fig. 1. This proposed method produces fast, robust, and efficient identification of parameters.</p> <p>GWO is a revolutionary meta-heuristic optimization method. Meta heuristic optimization approaches are in high demand for tackling optimization difficulties due to its simplicity, flexibility, derivation-free mechanism, and avoidance of local optima [2-4]. GWO primary assumption is to imitate grey wolves cooperative hunting behaviour in the wild. GWO stands apart from the competition in terms of model structure. For the optimization task, it performs well [4].</p> <p>At the moment, identification of battery parameters is a challenging task because of the factor that the battery is a complex non-linear device, and parameters are affected by several factors. The development of a battery model is essential for effective utilization of battery energy, identification of operating limitations, developing Fast charging algorithms, and safe charging/discharging. An accurate battery model is essential in the design of efficient BMS. In any battery powered system, the battery modelling plays a key role since it accurately reflects the chemical reactions that have occurred inside the battery. We can accurately predict the battery characterization/ estimation of battery parameters [5]. Estimation of battery parameters and states, are pivotal for superior management and control of battery usable capacity, for safe operation and to prolong the useful life of batteries. Batteries have many known parameters like current, voltage, temperature which can be directly accessed from the experiment or from the sensors. Battery states (SOC, SOH) are unknown parameters that can’t be extracted directly from the experiments. These states are estimated from the known parameters. Accurate estimation of battery parameters and SOC is a demanding task in real time applications because batteries are nonlinear, time-dependent electrochemical devices, and depend on several influential internal and external conditions [6]. So robust, efficient, and low complexity battery models are required to connect these unknown parameters with the known parameters to find the SOC, SOH, and to effectively use and manage the LIBs [7].</p> <p>The equivalent circuit model (ECM) is the most widely used battery modelling technique in EVs to model the LIBs. It is an easy and simple model that uses the electrical circuit components to describe the chemical reactions that occur inside the battery components such as resistors, capacitors, inductors, voltage source, etc. [8]. In this model, we can accurately reflect the chemical reactions like charge transfer reactions, diffusion process and each chemical reaction is represented by a particular electrical component [7].This model avoids the complexity in determination of parameters and is suitable for real-time applications as it provides moderate accuracy and less complexity. ECM gives a flexible trade-off between accuracy and complexity and easier to Identify the battery parameters like voltage, current, and the temperature. In recent times, second-order (2RC) ECM is a widely used model as it gives the best results when compared with the other ECM models in terms of complexity and accuracy. Research is going on in this field to update the parameters based on frequency [9].</p> Kamala Kumari Duru Praneash Venkatachalam Chanakya Karra Asha Anish Madhavan Sujith Kalluri Copyright (c) 2021 Kamala Kumari, Praneash, Chanakya, Asha Madhavan, Sujith Kalluri 2021-09-15 2021-09-15 1 01 Effect of Structural Modification on Ionic Conductivity of Solid Polymer Electrolytes https://spast.org/techrep/article/view/2771 <p>Solid polymer electrolyte (SPE) systems with poly (ethylene oxide) PEO as polymer and Rubidium Bromide (RbBr) as salt were prepared. The SPE system PEO: RbBr doped with 10 wt% of RbBr, which is stable and exhibits highest ionic conductivity of 4.02x10<sup>-6</sup> Scm<sup>-1</sup> was structurally modified by irradiating with low energy oxygen ion beam [1-3].&nbsp; Ionic conductivity and dielectric properties of the SPEs are evaluated by studying complex impedance spectra. SPE irradiated with ion beam of fluence 1x10<sup>15</sup> ions/cm<sup>2</sup> shows increase in ionic conductivity by one order (3.6 x10<sup>-5 </sup>Scm<sup>-2</sup>). The single peak in dielectric loss tangent curves indicates the fact that movement of ions through the polymer matrix is aided by segmental motion. The decrease in the relaxation time (τ) in the irradiated SPEs shows increased segmental motion as a result of reduced crystalline phase [4]. The decrease in the activation energy from 0.62eV (un-irradiated) to 0.30 eV (Irradiated with1x10<sup>15</sup> ions/cm<sup>2</sup>) observed in temperature dependence studies of ionic conductivity indicates the increase in amorphous phase. X-ray diffraction graphs shows increase in peak width along with reduced peak intensity of characteristic peaks [5] and thermal studies shows decrease in glass transition temperature (T<sub>g</sub>) as well as melting point (T<sub>m</sub>) in case of irradiated SPEs, These observation support the observed enhancement of amorphous phase due to irradiation which is the reason behind increased ionic conductivity.</p> H Manjunatha Copyright (c) 2021 H Manjunatha 2021-10-21 2021-10-21 1 01 Electrochemical Performance of MgCo2O4 as an Electrode Material for Supercapacitor Applications https://spast.org/techrep/article/view/651 <p>The fast depletion of fossil fuels forces the new generation to develop clean and sustainable energy substitutes. Numerous forms of renewable and environment-friendly energy sources, such as biomass, solar, wind energy, have been widely investigated. But it is also important to look into sophisticated devices for energy storage, which are a critical component in applications of green energy. A supercapacitor is one of the most recognized energy storage devices that offer great power density, a quick discharge-charge rate, and an incredibly long cycling lifespan. The super challenge with the supercapacitor is their lower energy density as compared to the battery. Numerous factors, such as type of electrode material, method of fabrication of electrode material, conditions of temperature and pressure, pH value, ageing time condition, exert a key function in enhancing the energy density of the electrode material of the supercapacitor. Ternary transition metal oxides (TTMOs), particularly spinel-type (AB<sub>2</sub>O<sub>4</sub>), received great attention in recent years as a potential electrode material for supercapacitor devices. Among the various spinel cobaltites, MgCo<sub>2</sub>O<sub>4 </sub>has a higher theoretical (3122 F/g), cycling stability, and coulombic efficiency which suggest that it could be used as a cost-effective energy storage medium [1]. Most of the studies reveal the electrochemical performance of MgCo<sub>2</sub>O<sub>4</sub> prepared by the hydrothermal method. Lifeng Cui <em>et al </em>fabricated the binder-free nanocones array of MgCo<sub>2</sub>O<sub>4</sub> over the Ni foam substrate via the hydrothermal method and the results revealed the maximum specific capacitance of 750 F/g at a minimum current density of 1.0 A/g [2]. On the other hand, S.G. Krishnan <em>et al </em>used the molten state method for the preparation of aggregated spheroidal particle morphology of MgCo<sub>2</sub>O<sub>4</sub> that results in specific capacitance of 320 F/g in 3 M LiOH electrolyte [3]. Yifei Teng <em>et al</em> synthesized MgCo<sub>2</sub>O<sub>4</sub> nanosheet arrays via the hydrothermal method to deliver the highest specific capacitance of 853.06 C/g (at 1 mA/cm<sup>2</sup>) [4]. In this regard, the present study addresses the fabrication of MgCo<sub>2</sub>O<sub>4</sub> (magnesium cobaltite) with the facile co-precipitation method as no study shows the electrochemical performance of MgCo<sub>2</sub>O<sub>4</sub> prepared by this method. The novelty of this work lies in the use of a different yet so simple co-precipitation method followed by calcination at 450<sup>◦</sup>C for 2 hr. To analyse the phase and sample purity, the fabricated MgCo<sub>2</sub>O<sub>4­</sub> material undergo X-ray diffraction (XRD) characterization through Rigaku Miniflex Japan X-ray Diffractometer. Fig 1(a) depicted the obtained XRD pattern with well-defined diffraction peaks at 2q = 18.91<sup>◦</sup>, 31.21<sup>◦</sup>, 36.61<sup>◦</sup>, 44.84<sup>◦</sup>, 55.56<sup>◦</sup>, 59.21<sup>◦</sup>, 65.19<sup>◦</sup>, and 77.16<sup>◦</sup> corresponds to (hkl) plane (111), (220), (311), (400), (422), (511), (440), and (533) respectively. The standard card of MgCo<sub>2</sub>O<sub>4­</sub> (JCPDS No. 02–1073) was used to assign all diffraction peaks [5]. There was no extra peak in the spectrum which confirms the high purity of the prepared material. Morphology of the powdered sample was obtained via JEOL JSM-6390LV Scanning Electron Microscope (SEM). The resulted nanorods morphology picture is shown in fig. 1(b). To test the compatibility of the synthesized material as an electrode material for supercapacitor, electrochemical characterizations were performed. Chronopotentiometry (CP)/Galvanostatic Charge-Discharge (GCD) and Cyclic Voltammetry (CV) techniques were performed through CHI 760E three-electrode electrochemical workstation using 2 M KOH electrolyte. The characteristic curves of CV are shown in fig. 1(c) with various scan rates from 1 – 20 mV/s within the voltage window of 0.0 – 0.45 V. The curve in the CV characteristic indicates the occurrence of Faradaic redox reaction at the electrode-electrolyte interface [6]. The shape of CV curves is well maintained at high scan rates with a peak voltage shift. It concludes the pseudocapacitor behaviour of the electrode material. Further, GCD patterns among various current densities are shown in fig. 1(d). The non-linear triangular shape of GCD curves further confirms the pseudocapacitor behaviour. The specific capacitance of the electrode material is calculated by using the equation: C<sub>s</sub> = (I &nbsp;t)/(m V), where C<sub>s</sub>, I, t, m, and V are the specific capacitance, current, discharge time, active mass of the material on the electrode (0.5 mg), and the potential window respectively. The calculated values of the specific capacitance are reported in table 1.</p> <p>It can be concluded that the present study insights the usefulness of the co-precipitation method in the fabrication of MgCo<sub>2</sub>O<sub>4</sub>. XRD pattern reveals the phase formation and purity of the fabricated sample. SEM analysis explored the unique nanorods morphology. Morphology of the material plays a key role in tuning the electrochemical performance of the electrode. Results of CV and GCD indicate the potential of MgCo<sub>2</sub>O<sub>4</sub> as an electrode material for supercapacitor application.</p> <p>The fast depletion of fossil fuels forces the new generation to develop clean and sustainable energy substitutes. Numerous forms of renewable and environment-friendly energy sources, such as biomass, solar, wind energy, have been widely investigated. But it is also important to look into sophisticated devices for energy storage, which are a critical component in applications of green energy. A supercapacitor is one of the most recognized energy storage devices that offer great power density, a quick discharge-charge rate, and an incredibly long cycling lifespan. The super challenge with the supercapacitor is their lower energy density as compared to the battery. Numerous factors, such as type of electrode material, method of fabrication of electrode material, conditions of temperature and pressure, pH value, ageing time condition, exert a key function in enhancing the energy density of the electrode material of the supercapacitor. Ternary transition metal oxides (TTMOs), particularly spinel-type (AB<sub>2</sub>O<sub>4</sub>), received great attention in recent years as a potential electrode material for supercapacitor devices. Among the various spinel cobaltites, MgCo<sub>2</sub>O<sub>4 </sub>has a higher theoretical (3122 F/g), cycling stability, and coulombic efficiency which suggest that it could be used as a cost-effective energy storage medium [1]. Most of the studies reveal the electrochemical performance of MgCo<sub>2</sub>O<sub>4</sub> prepared by the hydrothermal method. Lifeng Cui <em>et al </em>fabricated the binder-free nanocones array of MgCo<sub>2</sub>O<sub>4</sub> over the Ni foam substrate via the hydrothermal method and the results revealed the maximum specific capacitance of 750 F/g at a minimum current density of 1.0 A/g [2]. On the other hand, S.G. Krishnan <em>et al </em>used the molten state method for the preparation of aggregated spheroidal particle morphology of MgCo<sub>2</sub>O<sub>4</sub> that results in specific capacitance of 320 F/g in 3 M LiOH electrolyte [3]. Yifei Teng <em>et al</em> synthesized MgCo<sub>2</sub>O<sub>4</sub> nanosheet arrays via the hydrothermal method to deliver the highest specific capacitance of 853.06 C/g (at 1 mA/cm<sup>2</sup>) [4]. In this regard, the present study addresses the fabrication of MgCo<sub>2</sub>O<sub>4</sub> (magnesium cobaltite) with the facile co-precipitation method as no study shows the electrochemical performance of MgCo<sub>2</sub>O<sub>4</sub> prepared by this method. The novelty of this work lies in the use of a different yet so simple co-precipitation method followed by calcination at 450<sup>◦</sup>C for 2 hr. To analyse the phase and sample purity, the fabricated MgCo<sub>2</sub>O<sub>4­</sub> material undergo X-ray diffraction (XRD) characterization through Rigaku Miniflex Japan X-ray Diffractometer. Fig 1(a) depicted the obtained XRD pattern with well-defined diffraction peaks at 2q = 18.91<sup>◦</sup>, 31.21<sup>◦</sup>, 36.61<sup>◦</sup>, 44.84<sup>◦</sup>, 55.56<sup>◦</sup>, 59.21<sup>◦</sup>, 65.19<sup>◦</sup>, and 77.16<sup>◦</sup> corresponds to (hkl) plane (111), (220), (311), (400), (422), (511), (440), and (533) respectively. The standard card of MgCo<sub>2</sub>O<sub>4­</sub> (JCPDS No. 02–1073) was used to assign all diffraction peaks [5]. There was no extra peak in the spectrum which confirms the high purity of the prepared material. Morphology of the powdered sample was obtained via JEOL JSM-6390LV Scanning Electron Microscope (SEM). The resulted nanorods morphology picture is shown in fig. 1(b). To test the compatibility of the synthesized material as an electrode material for supercapacitor, electrochemical characterizations were performed. Chronopotentiometry (CP)/Galvanostatic Charge-Discharge (GCD) and Cyclic Voltammetry (CV) techniques were performed through CHI 760E three-electrode electrochemical workstation using 2 M KOH electrolyte. The characteristic curves of CV are shown in fig. 1(c) with various scan rates from 1 – 20 mV/s within the voltage window of 0.0 – 0.45 V. The curve in the CV characteristic indicates the occurrence of Faradaic redox reaction at the electrode-electrolyte interface [6]. The shape of CV curves is well maintained at high scan rates with a peak voltage shift. It concludes the pseudocapacitor behaviour of the electrode material. Further, GCD patterns among various current densities are shown in fig. 1(d). The non-linear triangular shape of GCD curves further confirms the pseudocapacitor behaviour. The specific capacitance of the electrode material is calculated by using the equation: C<sub>s</sub> = (I &nbsp;t)/(m V), where C<sub>s</sub>, I, t, m, and V are the specific capacitance, current, discharge time, active mass of the material on the electrode (0.5 mg), and the potential window respectively. The calculated values of the specific capacitance are reported in table 1.</p> <p>It can be concluded that the present study insights the usefulness of the co-precipitation method in the fabrication of MgCo<sub>2</sub>O<sub>4</sub>. XRD pattern reveals the phase formation and purity of the fabricated sample. SEM analysis explored the unique nanorods morphology. Morphology of the material plays a key role in tuning the electrochemical performance of the electrode. Results of CV and GCD indicate the potential of MgCo<sub>2</sub>O<sub>4</sub> as an electrode material for supercapacitor application.</p> <p>&nbsp;</p> Manpreet Kaur Copyright (c) 2021 Manpreet Kaur 2021-09-16 2021-09-16 1 01 Design and Performance analysis of improvised Poly-house solar bulk drying system for turmeric in North-East India https://spast.org/techrep/article/view/1549 <p>Abstract</p> Laxmi Narayan Sethi Abhijit Borah Copyright (c) 2021 Professor Sethi, Dr Borah 2021-10-08 2021-10-08 1 01 Design and Development of Pt-Sn/C based Electrocatalytic Sensor using Micro DMFC technology https://spast.org/techrep/article/view/218 <p>In this paper, a MEMS-based micro DMFC structure of 1cm<sup>2</sup> is proposed. It was fabricated using 3D printing technology. Pt-Sn/C was identified as the novel catalyst in DMFC technology which offers good current density. Pt-Sn/C was synthesized by the microwave-assisted chemical route and the nanoparticle of the same was derived. The MEA with the electrolyzer of Nafion membrane was fabricated with the acting anode medium of Pt-Sn/C and the cathode catalyst of pure Pt. The MEA of 1 cm<sup>2</sup> was attached with the DMFC cell and the experimentation was carried out for the methanol of different concentrations. Methanol vapour was allowed for the anodic oxidation at Pt-Sn/C where the air was pumped at the cathodic end for the reduction reaction. The produced current was amplified and the sensor’s minimal detection ability of methanol was tested and results are presented.</p> MUTHURAJA SOUNDRAPANDIAN SUBRAMANIAM CHITTUR KRISHNASWAMY SIVAKUMAR R Govardhan K Copyright (c) 2021 MUTHURAJA SOUNDRAPANDIAN, SUBRAMANIAM CHITTUR KRISHNASWAMY, SIVAKUMAR R 2021-09-08 2021-09-08 1 01 Economical sizing of energy storage system to meet the standards of Zero Energy Buildings https://spast.org/techrep/article/view/1671 <p>Energy storage is storing excess energy and converting it into various forms of energy with minimum losses. This can be achieved with an extensive analysis of load optimization, storage pattern, energy storage capacity, user’s autonomous requirement, etc. The gap between the supply and demand of electricity that is adoptable with conventional and renewable energy sources is challenging for the energy storage system design. Energy storage adds flexibility to networks in terms of load-leveling by which network imbalance can be predicted. Combining any renewable energy generation supported with batteries has been recognized as a solution to the problem by smoothing the variable power generated by renewable energy technologies through storage of electricity during the day and utilizing it during evenings. Zero Energy Building design requires economical energy storage options with a practical, viable option.&nbsp;</p> <p>In this research paper, a complete analysis has been designed and suggested an optimal economical solution for off-grid and on-grid Zero Energy Buildings by using a Homer pro optimization tool to validate the practical implementation.</p> G R K D SATYA PRASAD GOLLAKOTA Copyright (c) 2021 G R K D SATYA PRASAD GOLLAKOTA 2021-10-08 2021-10-08 1 01 A Review on Solar Tracking System https://spast.org/techrep/article/view/2358 <p>Solar energy is not just a renewable source of energy but also a sustainable energy resource around the world, which can easily fulfill the worlds growing energy demand, and to achieve this goal we need to track the position of the sun continuously so energy-absorbing panels would be normal to incident solar radiation for maximum energy production. From the last four to five decades many new systems, designs, theories, and techniques have been introduced in this field to facilitate the goal of energy demand.</p> <p>The study of this paper is reviewing the different types of solar tracking mechanisms with their solar tracking methods for solar tracking systems. This involves two solar tracking systems a duel axis and single-axis solar tracking system. This paper also overviews the difference in energy production between fixed panels and moving solar tracking panels. It also highlights limitations in a solar tracking system for its future scope.</p> Sagar Sabane Copyright (c) 2021 Sagar Sabane 2021-10-08 2021-10-08 1 01 Experimental investigation of boron arsenide as heat sink for thermoelectric generator https://spast.org/techrep/article/view/1790 <p>Thermal conductivity of heat sink decides the performance of heat sink and subsequently the performance of concerned system. Regular thermoelectric generators [TEG] uses aluminum heat sinks for faster heat rejection at cool side of TEG. This aluminum has thermal conductivity of 230 W·m<sup>−1</sup>·K<sup>−1</sup>. While the boron arsenide [BAs] has a 1300 W·m<sup>−1</sup>·K<sup>−1</sup>. This work uses the high thermal conductive boron arsenide as a heat sink for TEG to increases the temperature difference between two sides. This results in the increase in output power delivered by TEG. Further analysis has been made on cost effectiveness of system. Along with this a mathematical model of this system is presented to understand the relation between different parameters of the system.</p> alajingi ram kumar RMARIMUTHU Copyright (c) 2021 alajingi ram kumar, RMARIMUTHU 2021-10-09 2021-10-09 1 01 Regenerated graphite from failed commercial Li-ion batteries for high performance Na-ion battery applications https://spast.org/techrep/article/view/367 <p>Escalating production and consumption of lithium-ion batteries (LIB) leads to the accumulation of large number of end-of-life batteries having hazardous components which could become a potential threat to environment in the near future. Recycling and regeneration of cathode/anode materials from used LIB’s would be an effective solution for the development of a sustainable technology with economic benefits [1, 2]. Considering the low added value of graphite, initially recycling of anode didn’t consume much attention among researchers. The increased improper disposal of failed batteries and environmental pollution generated from graphite (also called spent graphite) triggered the scientific community to focus on recycle-reuse of spent graphite. In LIB’s graphite stands as the most popular negative electrode material till to date with highly reversible Li ion intercalation mechanism. On the other hand, implementation of graphite in sodium battery is still challenging due to the larger ionic radius of Na<sup>+</sup>, which would create hindrance to the ionic transport and sodium storage in the graphite structure [3, 4]. Over the past few years, many groups have reported the increased sodium ion storage in graphite via interlayer expansion. Also recently, solvated Na-ion intercalation (solvent-ion co-intercalation) in graphite is seeking much attention owing to its effect in enhancement of capacity and stability. Especially, due to the formation of ternary graphite intercalation compounds in the gylme based electrolyte systems [5, 6].</p> <p>In the present work, we focused on the recycling and regeneration of spent graphite as a potential anode material for sodium ion battery (NIB) technology. We report a simple, low cost and thermal treatment-free approach for the recycling of spent graphite from a failed LIB. Regeneration of graphite was accomplished with optimizing the interlaying spacing expansion via a thermal-treatment-free solvent/acid treatment. X-ray diffraction pattern reveals the phase purity and magnitude of inter planar expansion of the acid treated graphite which is further confirmed using Transmission electron microscopy analysis. Surface chemical analysis evidenced the presence of organic compounds raised from solid electrolyte interface layer (SEI) formed on spent graphite, whereas the regenerated graphite was found to be SEI-free that indicates the effectiveness of the recycling methodology implemented. As regenerated phase pure graphite exhibited outstanding electrochemical performance with the aid of an ether derived electrolyte, diglyme. The optimized regenerated graphite exhibited ultra-long cycle life and ultra-high rate which is possibly due to the the synergetic effect of regeneration process and electrolyte combination. We strongly believe that this work will give a new insight in the field of recycling and regeneration of graphite anodes for future sodium ion battery applications. We shall present a comparison of results reported in the literature for graphite based NIB applications.</p> <p><strong>&nbsp;</strong></p> SILPASREE S J Copyright (c) 2021 SILPASREE S J 2021-09-17 2021-09-17 1 01 Redox Mediated Neutral Electrolyte Solution for High Performing Ni(OH)2-MnO2-rGO Supercapacitor Electrode https://spast.org/techrep/article/view/1231 <p>The most ascertain key to resolving the ever-increasing global energy crisis is the enrichment of electrochemical energy storage technologies. Besides, towards achieving the goals of SDG-7 (including zero-emission vehicles, modern use of electricity, and green grid storage, etc.), the development of heavy-duty supercapacitors (SC) is now a center of focus for scientists. Among the various strategies and efforts, reduced graphene oxide (rGO) is the most studied carbonaceous material for the fabrication of EDLC based SC [1]. But, one of the major problems regarding rGO based electrode materials for SC is its uncontrolled stacking layer formation property which is not usually favorable for electrical charge storage [2]. Although the pristine rGO, prepared via chemical vapor deposition is highly conductive with a large surface area, a chemically synthesized rGO possesses much lower electrical conductivity with a lower surface area [3]. Usually, rGO prepared by the modified Hummer method contains so many unwanted functional groups that hinder the actual conducting properties of rGO and significantly affect the surface area. Another reason is the random stacking of rGO interlayers. This work demonstrated the approach to resolve the electrical conductivity problem by the successful incorporation of α-Ni(OH)<sub>2</sub> and γ-MnO<sub>2 </sub>on and in between the hydrothermally synthesized rGO interlayers by a simple gel formation method. The crystalline phase of the metal oxides in the Ni(OH)<sub>2</sub>-MnO<sub>2</sub>-rGO is characterized by X-ray Diffraction (XRD) and found to be α-Ni(OH)<sub>2</sub> and γ-MnO<sub>2</sub>. Initially, KMnO<sub>4</sub> abruptly reacted with glycerine and produced hydrated manganese oxide in the presence of GO and NiNO<sub>3</sub> solution. The hydrothermal reaction was carried out at 180°C for 24 h to convert this material into Ni(OH)<sub>2</sub>-MnO<sub>2</sub>-rGO. The incorporation of Ni(OH)<sub>2</sub> and MnO<sub>2</sub> unzipped the stacked layers of rGO sheets and facilitated a way to enhance the interlayer distance of rGO sheets [3,4]. Besides, the incorporation of single or multiple metal oxides or hydroxides with the pure rGO layers always provides extra surface area and induces pseudocapacitance with a suitable electrolyte system. Due to the synergistic effects of Ni(OH)<sub>2</sub> and MnO<sub>2</sub>, the overall electrochemical performance of as-synthesized hybrid has shown high performance as SC electrodes [4]. Now, the architecting of proper electrode materials is not the only challenge remaining towards fabricating a high-performing SC device. Instead, the equal focus on electrolyte architecting is also a must issue of achieving maximum efficiency from the electrode material.</p> <p>Usually, aqueous electrolytes (Na<sub>2</sub>SO<sub>4, </sub>H<sub>2</sub>SO<sub>4</sub> KOH) with rGO based hybrids are always a safe choice for the fast-charging and discharging features because of their higher electronic conductivity and lesser solution resistance. However, the limited working window of aqueous electrolytes limits the energy density of an energy storage device. Although organic electrolytes are commonly used in commercial energy storage devices, organic liquids are still under consideration due to their high cost, low conductivity, high volatility, and extremely flammable nature, making them unsafe for high-voltage and long-term operation. So, towards this solution, an adequately designed electrolytic system is required to achieve maximum capacitance with high energy density and long cyclic stability of a hybrid SC device. Towards this solution, a redox-mediated (Na<sub>2</sub>SO<sub>4</sub> and K<sub>4</sub>FeCN<sub>6</sub>) electrolyte solution was used for the first time with the Ni(OH)<sub>2</sub>-MnO<sub>2</sub>-rGO electrode as shown in fig. 1. During the charging-discharging process, K<sub>4</sub>FeCN<sub>6 </sub>introduces a reversible redox (FeCN<sub>6­</sub><sup>4-</sup> to FeCN<sub>6­</sub><sup>3-</sup> ) reaction in the hybrid electrode and electrolyte interfaces. During this time, the adsorption and desorption of FeCN<sub>6­</sub><sup>4-</sup> and FeCN<sub>6­</sub><sup>3-</sup> took place on the electrode surface [5]. Thus, the redox-mediated aqueous media facilitated different faradic reactions to introduce more pseudocapacitance without hampering the material stability. Hence, a high specific capacitance of 870 Fg<sup>-1</sup> was found at 1 Ag<sup>-1</sup> current density with a high energy density of 30.2 Whkg<sup>-1</sup> by using symmetrical two-electrode setup. &nbsp;Besides, even after 5,000 cycles, high capacitance retention of 92 % was found with maintaining 95% Coulombic efficiency. The total electrochemical evaluation of Ni(OH)<sub>2</sub>-MnO<sub>2</sub>-rGO with different electrolytes is presented in table 1. It is expected that this work will contribute to developing a high-performing and low-cost SC device that can be used in smart and sustainable hybrid vehicles.</p> Yeasin Arafat Tarek Ragib Shakhil Chanchal Kumar Roy Shakhawat Hossain Firoz Copyright (c) 2021 Yeasin Arafat Tarek, Ragib Shakil, Chanchal Kumar Roy, Shakhawat Hossain Firoz 2021-09-28 2021-09-28 1 01 Ni0.85Se/MoSe2 Interfacial Structure: An Efficient Electrocatalyst for Alkaline Hydrogen Evolution Reaction https://spast.org/techrep/article/view/632 <p>Increasing human population and the associated surge in the energy consumption result in the depletion of non-renewable fossil fuels. This demands development of sustainable energy sources to combat the on-growing energy crisis. One of the promising approaches towards achieving uninterrupted energy supply is to employ hydrogen as an alternative fuel as it possesses highest specific energy (142 MJ/Kg) [1]. Hydrogen gas is generally produced from the polymer electrolyte membrane (PEM) or alkaline electrolyzers which works in acidic or alkaline media, respectively. Platinum (Pt) based materials are state-of-the-art electrocatalysts for efficient hydrogen evolution reaction (HER) in acidic medium. On the other hand, a good performing HER electrocatalyst is highly desirable in alkali medium as the activities of best performing electrocatalysts in acidic medium (including Pt) have been compromised in alkaline medium by several orders. This is due to the additional energy barriers originated from the water dissociation step (cleavage of H-OH bond) which is crucial to trigger the HER process in alkaline medium [2]. In this context, heterostructural engineering has been emerged as a rational materials design strategy to achieve promising HER activity in alkali medium. This generally involves synergistic coupling between water dissociation promotors (i.e. Ni/Co based materials) and Pt surface. In the heterostructure, the water dissociation (H<sub>2</sub>O+e<sup>-</sup>→H*+OH<sup>-</sup>, Volmer step) occurs initially over the promotor surface in the heterostructure to produce adsorbed hydrogen atoms (H*). Subsequently, the Heyrovsky step (H*+ H<sub>2</sub>O+2e<sup>-</sup>→H<sub>2</sub>) or Tafel step (H*+H*→H<sub>2</sub>) results in the production of H<sub>2</sub> gas over the Pt site [3]. Besides expensive Pt, two dimensional transition metal dichalcogenides (TMDs) are promising candidates for HER in acidic medium due to their near zero hydrogen free energy (ΔG<sub>H*</sub>), which is a key discriminator to evaluate the catalytic performance. Similar to the Pt, MoX<sub>2</sub> (X=S, Se) surface is favourable to accelerate the Heyrovsky process, irrespective of the sluggish water dissociation step (Volmer step, H<sub>2</sub>O to H* formation) in alkali medium. To accelerate the alkaline HER process over MoX<sub>2</sub> the synergistic coupling with water dissociation (Ni/Co-based) promoters is highly desired. Despite several metal sulfide-based heterojunctions have been tested for alkaline HER, only few reports are available in the literature based on the selenium counterpart. For instance, Wang et al. have developed hierarchical MoSe<sub>2</sub>–CoSe<sub>2</sub> nanotubes for the improved hydrogen evolution reaction [4]. In another report, strongly coupled NiSe with MoSe<sub>2</sub> showed better catalytic activity compared to the MoSe<sub>2</sub>. The synergistic coupling helps in the reduction of ΔG<sub>H-OH </sub>(water dissociation step) and ΔG<sub>H*</sub> as close to zero thereby facilitating the HER in alkaline medium [5]. To prepare the Ni/Co-selenide and MoSe<sub>2</sub> heterostructures, the direct selenization of the metal (Ni/Co) molybdates precursors is the commonly used method. However, the adopted synthetic route could not provide the control over the composition and active site exposure of the catalyst which play significant roles during the catalysis. Hence, we aim to design an interfacial structure with abundant active sites by two step selenization approach, such that one material acts as a support for the uniform growth/dispersion of the other component. Firstly, Ni<sub>0.75</sub>Se was prepared from solvothermal method. Subsequently, certain amounts of as-prepared Ni<sub>0.75</sub>Se was introduced into the hydrothermal synthesis of MoSe<sub>2</sub> to obtain a series of Ni<sub>0.85</sub>Se/MoSe<sub>2</sub> hetero-structures. This method allows tuning of the composition in the heterostructure by simply varying the amount of Ni<sub>0.75</sub>Se or the precursor used for the MoSe<sub>2</sub>. The phase analysis of the Ni<sub>0.85</sub>Se/MoSe<sub>2</sub> hetero-structure indicates the transformation of Ni<sub>0.75</sub>Se into Ni<sub>0.85</sub>Se during the composite formation which is facilitated by the reduction environment. The morphological analysis reveals that the interfacial structure comprises of interconnected Ni<sub>0.85</sub>Se nanoparticles and MoSe<sub>2</sub> flakes with abundant heterojunctions. The resulted composite materials displayed superior alkaline HER activity compared to pristine MoSe<sub>2</sub>, especially Ni<sub>0.85</sub>Se/MoSe<sub>2</sub> (20) exhibits a current density of 10 mA cm<sup>-2</sup> at an overpotential of 108 mV along with a good durability. The improved electrocatalytic activity of Ni<sub>0.85</sub>Se/MoSe<sub>2</sub> in alkali medium could be attributed to (i) efficient water dissociation process over Ni<sub>0.85</sub>Se promotor and (ii) the exposure of more catalytic active sites (edges) of MoSe<sub>2</sub> resulted from the interfacial structure [6]. Further, the as-prepared Ni<sub>0.75</sub>Se has shown improved OER activity, which consumes an overpotential of 340 mV to reach a current density of 10 mAcm<sup>-2</sup>. Additionally, the overall water splitting was demonstrated by constructing an alkaline electrolyzer using the best performing HER and OER catalysts. Ni<sub>0.85</sub>Se/MoSe<sub>2</sub> (20) and Ni<sub>0.75</sub>Se were employed as cathode and anode, respectively as shown in Fig.1. The alkaline electrolyzer delivers a current density of 10 mA cm<sup>-2 </sup>at a cell potential of 1.7 V. In addition, the long-term stability experiment for 24 h and the post catalytic characterization revealed the high robustness of the Ni<sub>0.85</sub>Se/MoSe<sub>2</sub> interfacial structure for alkaline hydrogen evolution reaction. Besides, the synthetic approach could pave a way for designing various interfacial/heterostrucures based on TMDs to attain superior HER activity in both alkaline and acidic media. Furthermore, the substrate (carbon fibre paper) and the electrocatalysts used in this work are earth abundant and cost effective, this could be efficient method for the large scale hydrogen fuel production.</p> <p><img src="https://spast.org/public/site/images/harishreddy9396/picture1.png" alt="" width="700" height="438"></p> <p><strong>Fig.1.</strong> (a) Schematic representation of overall water splitting reaction using the alkaline electrolyzer where Ni<sub>0.85</sub>Se/MoSe<sub>2</sub> (20) and Ni<sub>0.75</sub>Se were used as electrocatalysts for HER and OER, respectively. (b) Backward polarization curve for overall water splitting reaction.</p> HARISH REDDY INTA Copyright (c) 2021 HARISH REDDY INTA 2021-09-19 2021-09-19 1 01 Transition Metal based carbide and nitride electrocatalysts for high-performance alkaline seawater electrolysis https://spast.org/techrep/article/view/2787 <p>To meet the practical demand of world’s energy requirements sustainable energy<br>technology has received enormous attention in recent years. Specifically, electrochemical<br>water splitting is considered to be the cleanest technique for the production of promising<br>fuels like hydrogen and oxygen. Also, electrolysis is one of the efficient and potential means<br>of energy conversion, with minimal environmental footprint. As seawater is one of the most<br>abundant natural resources on our planet, electrolysis of seawater is not only a promising<br>approach to produce clean energy, but also of great significance to seawater desalination.<br>Moreover, to enhance reaction rates, catalysts are required to minimize overpotential. So,<br>developing highly efficient, low-cost, durable, non noble metal catalysts for overall water<br>splitting is of the great importance for the production of H2 and O2. As alternatives to the<br>noble metal electrocatalysts are essential to address the needs of scale, transition based<br>materials were preferred due to the significant attention they attained. In this context,<br>transition metal carbide (TMC) and transition metal nitride (TMN) thin films were preferred as<br>they have attracted significant attention due to their high catalytic activity, distinctive<br>electronic structures, and enhanced surface morphologies. Finally, the popular bi-functional<br>catalysts usually shown good activity for one half reaction at expense of the activity for<br>another half-reaction, thus given a moderate performance for overall water splitting. Also, the<br>implementation of seawater electrolysis requires robust and efficient electrocatalysts that<br>can sustain seawater splitting without chloride corrosion, especially for the anode. So, to<br>meet the practical demand of overall water splitting, we aimed at developing highly efficient,<br>low-cost, durable, non noble metal catalysts for overall water splitting.<br>Herein, four combinations of transitional metal based carbides and nitrides were<br>prepared. i.e., vanadium aluminium carbide (VAlC), vanadium aluminium nitride (VAlN),<br>titanium aluminium carbide (TiAlC), titanium aluminium nitride (TiAlN). Thin films for all the<br>compounds were developed using reactive magnetron sputtering. Benefiting from the high<br>catalytic activity, distinctive electronic structures, enhanced surface morphologies and<br>synergistic effect; VAlC thin film exhibited good catalytic activity for both oxygen evolution<br>reaction (OER) and hydrogen evolution reaction (HER) in seawater. It achieved current<br>density of 18mA cm−2 at record low voltage of 0.25 V for HER, current density of 58mA cm−2<br>at an overpotential of 1.16 V for OER. Following the same trend VAlN also produced similar<br>results by achieving current density of 15 mA cm−2 at 0.2475 V for HER, current density of<br>52 mA cm−2 at 1.16 V for OER. Whereas TiAlC and TiAlN has achieved only a current<br>density of 12 mA cm−2 and 7.6 mA cm−2<br>respectively at 0.3 V for HER. Current density of 32<br>mA cm−2 and 28 mA cm−2 respectively at an overpotential of 1.16 V for OER. The difference in the performances might be because vanadium is electrocatalytically active in all V+3, V+4<br>and V+5 states whereas, Ti ion is electrochemically active only under certain circumstances.<br>This work advances the development of seawater electrolysis for large-scale hydrogen<br>production and paves an avenue for fabricating highly efficient, low-cost durable, and non<br>noble metal electrocatalysts.</p> Rajagopal Peri Mathan Kumar P Mohanaselvi T Muthuraaman B Copyright (c) 2021 Rajagopal Peri, Mathan Kumar P, Mohanaselvi T, Muthuraaman B 2021-10-19 2021-10-19 1 01 Electrodeposition of Inorganic, Organic and Hybrid Thin Films for Energy Conversion and Storage https://spast.org/techrep/article/view/1304 <p>There are no winners nor losers in the fight against the global climate change. It is the fight we cannot lose, in which all of us must become winners for our survival. The challenges for carbon neutrality (CaN) by 2050 are now real and eminent.</p> <p>Aside from the political challenges to avoid all the ridiculous international conflicts to hinder the actions for CaN, near complete change of our energy system to renewable ones is the most important technical challenge. It is not only about electrification of our life by renewable sources such as solar and wind. Energy and resource saving technologies are important as well. Also, because of the intermittency of renewable power, technologies for storing electricity in a large-scale battery and ideally converting it into chemical fuels are needed.</p> <p>We have been working on electrodeposition of functional thin films for the above-mentioned purposes for over 1/4 centuries. Electrodeposition is a low-cost and scalable solution processing of thin film materials. Starting from inorganic compound semiconductors such as metal chalcogenides used in thin film solar cells [1], discovery of self-assembly of nanostructured ZnO/organic dye hybrid thin film lead to an industry/university national project for flexible dye-sensitized solar cells in 2000’s [2]. And by now, solar electricity from Si panels became the cheapest, which was bitter for a researcher of organic solar cells, but welcome as an individual, so that production of renewable electricity is no longer an issue but its storage is highly important for on-demand use of renewable energy. We then shifted our research to redox flow batteries as well as electrocatalysis for water splitting and CO<sub>2</sub> reduction [3,4]. Once again, electrodeposition plays an important role. The target now is a hydrogen-bonding conductive organic polymer such as polydopamine that shows high catalytic activities for hydrogen evolution and CO<sub>2</sub> reduction reactions.</p> <p>This way, our explorations have come to cover all kinds of materials to be electrodeposited. In fact, it is not too useful to categorize materials as organic or inorganic, since history of the synthesis remains in their properties. Variety of control parameters in the electrodeposition process can result in fine-tuning of the products to suit the need in applications. Scientifically understanding the phenomena of electrochemical precipitation is thereby the most important for establishing a foundation for industrial development of electrodeposition.</p> <p>In this talk, a review of the past/history of our research, the present and the future will be discussed. Also, the foundation of Yamagata University Carbon Neutral (YUCaN) research center to tackle the broader goals of carbon neutrality will be announced and explained.</p> Tsukasa Yoshida Copyright (c) 2021 Tsukasa Yoshida 2021-09-30 2021-09-30 1 01 Cyclo[18]carbon (C18) as Electron Acceptor for Organic Solar Cells Applications https://spast.org/techrep/article/view/2170 <p>Organic solar cells (OSCs) can be a theoretically promising technology for providing clean and renewable energy. The significant advantages of OSCs compared to their counterparts are low-cost, lightweight, flexibility.[1] However, efficiency limitations, as well as long-term reliability, are major concerns. The design and development of new non-fullerene acceptors (NFAs) (used as electron acceptors in organic solar cells) is currently a major focus of the research. Several NFAs, such as fused ring aromatic cores with strong electron acceptors and rylene diimide-based materials, have shown promising power conversion efficiencies (PCEs).[2] Recently developed molecules ITIC and Y6-based acceptors have shown PCE of more than 18%.[3,4] However, key information related to structure-property relationships, donor-acceptor energy levels matching, and understanding the energy losses are important to improve the efficiencies of devices. In this context, computational studies provide more insights into the molecular level understanding on energy level matching and molecular packing between donor and acceptor materials.</p> <p>In this investigation, we computationally study whether the recently synthesized Cyclo[18]carbon (C<sub>18</sub>) molecule can be used as the electron acceptor in organic solar cells. Strong π-electron delocalization and high electron affinity make C<sub>18</sub> as the electron acceptor.[5] Thus, density functional theory-based methods are used to characterize the electronic properties, aromaticity, and the nature of interactions between C<sub>18</sub> molecules. The important criteria which control charge mobility are reorganization energies and electronic coupling between molecules. We have calculated the reorganization energies using state-of-the-art methods. The nature of interaction between C<sub>18 </sub>molecules is analyzed using symmetry-adapted perturbation theory (SAPT). The results obtained from this analysis are useful to understand the packing between molecules. The calculated reorganization energies and electronic couplings have shown good charge transport properties.</p> <p><img src="https://spast.org/public/site/images/maheshr06/fig1.png" alt="" width="320" height="203"></p> <p><strong>Fig.1.</strong> Optimized geometry of polyyne and cumulene structure along with bond angle and distance using CAM-B3LYP/6-311++G (2d,p) method.</p> <p>The optimized geometries of monomers are shown in fig. 1, along with the bond length data obtained from three different DFT methods. For this study, selecting a suitable DFT method is very important to identify the correct bond length and electronic structure of these molecules. In this study, we have demonstrated the importance of long-range corrected DFT methods for the proper description of highly delocalized bonds.</p> <p>The aromatic behavior of molecules depends on the nature of bonding (σ and π bonds) between carbon and carbon (C-C) atoms. From our DFT simulations we found the double aromatic nature of C18 rings. The delocalization of two scaffolds of π-electrons oriented towards in-plane (π<sub>in</sub>) and out-of-plane (π<sub>out</sub>). Thus, there is a double aromaticity behavior in the circular form of C<sub>18</sub> molecules. The bond order differences in polyyne and cumulene rings reflect through aromatic character.</p> <p><img src="https://spast.org/public/site/images/maheshr06/fig2a.png" alt="" width="530" height="189"></p> <p><strong>Fig.2.</strong> Graphical representation of energy decomposition analysis of two C18 rings at a. eclipsed position change in vertical distance from 2.5Å to 4.5Å. All calculations are carried out using SAPT/aug-cc-pvdz level of theory.</p> <p>Based on the results obtained from both analyses, we consider only cumulene ring structure for further analysis. The energy decomposition analysis on dimers of C<sub>18</sub> is carried out to gain more insights into the nature of interactions between the ring structures and also packing of these molecules in the thin-films. One can see from fig. 2 that the major contribution to the stabilization complex came from the dispersion energy. The large repulsive exchange energy compensates attractive terms. However, it is interesting to note that the large exchange-repulsion indicates the considerable overlap of electron densities. Such a large overlap of electron density might lead to large electronic coupling between rings. We have calculated the electronic coupling values between the rings, and we found (LUMO-LUMO) electronic couplings values in the rages of 400 meV. As discussed before, large electronic couplings and low internal reorganization energies are the key parameters for better charge mobilities. Results obtained from our calculations indicate that the C<sub>18</sub> may exhibit better charge mobilities as it shows large electronic coupling with low reorganization energies.</p> <p><img src="https://spast.org/public/site/images/maheshr06/fig3.png" alt="" width="664" height="265"></p> <p><strong>Fig.3.</strong> pictorial representation of hole and electron wavefunctions in pentacene-C18 clusters in the lowest excited states.</p> <p>Further, we have also studied donor-acceptor complexes based on pentacene-C<sub>18</sub> clusters as model systems. Time-dependent DFT analysis is carried out to characterize the excited state properties of these clusters. Fig. 3 shows the hole and electron wavefunctions of pentance-C<sub>18</sub> clusters in the lowest excited state. The excited state analysis on these clusters reveals that the C<sub>18</sub> molecule can be used as acceptor molecules as the lowest excited state has charge transfer in nature (hole localized on pentacene and electron localized on C<sub>18</sub>). We have studied how molecular packing between donor and acceptor molecules impact the hole and electron delocalization in the excited states. These results give insights into the charge dissociation property of the system of interest. All these results will be useful to provide designing rules for the experimentalist. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> Mahesh Kumar Ravva Sheik Haseena Prakash Muthuramalingam Maiyelvaganan K. R. Copyright (c) 2021 Mahesh Kumar Ravva, Haseena, Prakash, Maiyelvaganan 2021-10-08 2021-10-08 1 01 Analysis of Solar Photovoltaic technologies integrated with storage systems and Fuel Cell Vehicle. https://spast.org/techrep/article/view/1568 <p>“51 billion tons”, is the quantity of greenhouse gases the world adds to the atmosphere every year and this number is rising at an alarming rate. Climate change is not an imaginary event. Floods, storms, droughts, and heatwaves have been on the rise, worldwide. At the same time due to the increase in the concentration of greenhouse gases in the atmosphere, average temperature &amp; rainfall around the globe are constantly rising and are becoming more variable and extreme. “Zero” is the number we need to aim for i.e., complete reliance on sustainable, cleaner, self-sufficient, and zero-carbon emission sources of energy systems. Electricity production contributes 27% of a total greenhouse gas emission and transportation (Automotive sector, planes, ships, etc.) contributes to a total of 16% of greenhouse gas emission. This demands prompt actions to provide solutions to neutralize above a total of 43% of global greenhouse gas emissions. It is extremely essential to produce electricity from renewable sources. Considering the current technological setup, solar energy is a promising and freely available energy source for managing long-term issues in the energy crisis. The major issue with utilizing solar energy is the fluctuations caused in the production due to its reliance on various natural factors such as cloud density, sun-oriented radiation, etc. All things considered, the production site is unable to respond deftly to the demand of consumers which results in overproduction and supply to the grid refer fig.1. This surplus energy is stored or wasted, to safeguard the grid integration balance. The excess energy generated is stored by various methods and is utilized subsequently during deficiencies or irregular periods of energy generation, thereby controlling the output in a better form. Various solar power technology integration with different dynamic subsystems is the way forward.</p> <p>It is extremely difficult for these solar-powered subsystems to renovate post setup. Therefore, to select the suitable technology for a particular geographical location, therefore there is a need to comprehend and analyse the fundamental systems and general activity elements of reasonable photovoltaic innovations.</p> <p>The major concern of the automotive sector is the need for clean fuel. The answer to this is a battery, but this raises limitations such as long charging time and compromising range.&nbsp;</p> <p>Because of the cited concerns, we suggest a hybrid ecosystem integrating the solar PV technology with hydrogen-powered FCV (Fuel- cell Vehicles). This paper comprises a detailed analysis of system integration with various combinations of PV technology and different electrolysis processes for generating green hydrogen. Analysis of the round-trip efficiency of different photovoltaic technologies integrated with relevant storage systems will be presented.&nbsp;</p> <p>The scope of solar technologies in this paper is focused to standard, tracking (1 axis, 1.5 axis, 2 axis), bi-facial and perovskite painted silicon cell. The storage systems integrated with the mentioned solar technologies include pumped hydropower, compressed air, liquid metal batteries, and flywheel.</p> <p>The paper suggests the best possible combination of discrete technologies to achieve the “Zero” figure which enables us to have complete reliance on sustainable, cleaner, self-sufficient, and zero-carbon emission sources of the energy system.</p> <p><img src="https://spast.org/public/site/images/yash_mistry/solar-genration-and-load-curve.png" alt="Typical daily solar generation and load curve: Area 1 represents user’s power purchase; area 2 represents the power exported to the grid; area 3 represents the solar generation used locally.[2]" width="822" height="438"></p> <p><strong>Fig.1.</strong> Typical daily solar generation and load curve: Area 1 represents user’s power purchase; area 2 represents the power exported to the grid; area 3 represents the solar generation used locally.[2]</p> Yash Mistry Shreyas Khandekar Copyright (c) 2021 Yash Mistry, Shreyas Khandekar 2021-10-08 2021-10-08 1 01 The Production of Hydrogen by Biological Method from Crude Glycerol https://spast.org/techrep/article/view/1733 <p>Hydrogen (H<sub>2</sub>) is a clean, effective and renewable fuel which can be produced by different methods including biological ones, namely fermentation. To improve fermentative H<sub>2</sub> production the strategies, implicating use of by-products, utilization of carbon containing organic wastes and optimization of biotechnology process conditions, are developed. Glycerol, a biodiesel by product, can serve as a cheap carbon containing source to produce H<sub>2 </sub>by mesophilic bacteria.</p> <p>Unlike fossil fuels, Hydrogen contains no carbon and hence does not generate CO<sub>2</sub> emission at the point of use. This is unsustainable for the reason that using natural gas depletes fossil fuel resources and the process generates significant Greenhouse gas (GHG) emission. Biodiesel is one of those alternative fuels which have picked up keen interest of the people due to its similar properties to diesel. However due to Biodiesel being costlier than diesel in the present scenario, it has not been preferred to diesel. Biodiesel has become more competitive against petroleum diesel due to the higher prices of crude oil and increased demand for environmentally. However, if the cost of Biodiesel is reduced then its effective usage can be made, either by utilising its by product (Glycerol) effectively. Data on metabolic pathways and dependence of H<sub>2</sub> production on external factors during glycerol fermentation are summarized. Optimal conditions and analysis of gas sample are highlighted. All of these are significant for further development H<sub>2</sub> production from glycerol and perspective for applied energy systems.</p> <p>To overcome the challenge for the demand of clean energy, by utilizing waste resource through economical method.</p> PRIYA S Rakesh kumar TEJAS S MADANE POOJA C KALAMADI Kruthika M K Copyright (c) 2021 Mrs PRIYA S, Rakesh kumar, TEJAS, POOJA, Kruthika 2021-10-08 2021-10-08 1 01 GQDs assisted BaCoS/MWCNT composite as a promising candidate for supercapacitor and a perspective Pt-free counter electrode in DSSC https://spast.org/techrep/article/view/1768 <p>Incorporation of carbon materials into transition metal sulfides (TMS) for counter electrode (CE) of the dye sensitized solar cell (DSSCs) are common way to enhance the photovoltaic performance. This enhancement is almost always attributed to an increase in overall conductivity due to the addition of carbonaceous materials. However, the role of these carbonaceous materials in promoting solar cell efficiency is rarely discussed. Here, the low-cost transition metal sulfides has been considered as alternative to Pt.&nbsp; In this paper, pristine barium cobalt sulfide (BCS) and Graphene Quantum Dots (GQDs) supported barium cobalt sulfide/MWCNT (BCS/MWCNT/GQDs) composites are successfully prepared by facile hydrothermal method and employed as a counter electrode for DSSC.&nbsp; The structural and crystalline nature of the BCS composites are analyzed by X-ray diffraction (XRD) and the cubic of Ba<sub>6</sub>Co<sub>25</sub>S<sub>27</sub> is detected.&nbsp; The morphology of the BCS, BCS/MWCNT and BCS/MWCNT/GQD composites are observed through Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The chemical valence states of GQD enriched BCS/MWCNT composites are determined using X-ray photoelectron spectroscopy (XPS). The characterizations of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and tafel polarization decay are used to investigate the electrochemical activity of the prepared CEs under I<sup>-</sup>/I<sub>3</sub><sup>-</sup> electrolyte. From CV, the GQD incorporated BCS/MWCNT CE shows the low E<sub>PP</sub> and higher J<sub>PC</sub> values than BCS and BCS/MWCNT CEs. Moreover, the Nyquist spectra confirms the BCS/MWCNT/GQD CE yield low charge transfer resistance (R<sub>CT</sub>) than BCS and BCS/MWCNT composites, which indicating GQD functions has a great impact in electrocatalytic activity than the conductivity promoter. So, the dye sensitized solar cell is fabricated using dye adsorbed TiO<sub>2</sub> photoanode, iodine/iodide electrolyte and prepared BCS, BCS/MWCNT and BCS/MWCNT/GQD composites as CEs. Under optimal condition, BCS/MWCNT/GQD CE based DSSC shows the open circuit voltage (V<sub>OC</sub>) of 0.75, short circuit current (J<sub>SC</sub>) of 10.54 mA/cm<sup>2</sup>, fill factor (FF) of 0.58, and PCE of 4.38%, which is 42% higher than pristine BCS CE (2.53%). This phenomena can be attributed to the incorporation of the carbon materials (GQDs and MWCNT) in BCS composite, which offers large electrochemical surface area, improvement in electrical conductivity, low peak to peak separation value (E<sub>PP</sub>) and low charge transfer resistance (R<sub>CT</sub>) than pristine BCS composite. Further, the prepared composites are employed as working electrode for supercapacitor and the device fabricated using BCS/MWCNT/GQD composite shows typical faradic redox features and the impressive specific capacitance of 434 C/g at 2 A/g. The good electrochemical performance is due to the layered structure of GQDs and strong interaction between BCS and GQDs, which increase the diffusion of electrolyte ions/electrons and decrease the intrinsic resistance and contact resistance. The benefits of GQDs enriched BCS composites confirm their unique properties for potential applications in the field of energy conversion and energy storage applications.</p> <p>&nbsp;</p> GAYATHRI VELUCHAMI Copyright (c) 2021 GAYATHRI VELUCHAMI 2021-10-09 2021-10-09 1 01 Terephthalate Linkage Spherical Cerium-based Metal Organic Framework as Sustainable Electrodes for Rechargeable Li-ion Batteries https://spast.org/techrep/article/view/1020 <p>Searching for a new type of sustainable electrode has to overcome the energy crises in the field of green energy storage systems. Past few decays, lithium-ion batteries (LIBs) are the inevitable potential candidate in the field of hybrid vehicles to wearable electronic devices due to their long cycle life, high power, and energy density [1]. Cerium is the most reactive element in the lanthanide serious, and comparatively cheap element other rare earth metals. It processes great valuable properties such as oxygen capacity, optical, defluoridation properties. Also fast and direct transformation of Ce(III) and Ce(IV) redox behavior but have not been achieved in many details in the field of energy storage applications [2]. In this work, the spherical cerium-based metal-organic framework (Ce-MOF) is successfully synthesized via solvothermal method and terephthalic acid (TPA) used as a linker, which is obtained from the waste resource of polyethylene terephthalate (PET) and furnished as a linker onto metal sites. The obtained Ce-MOF is involved in postcalcination at 500<sup>o</sup>C to achieve CeO<sub>2</sub>, moreover, to enhance the specific capacity melamine-formaldehyde resin coated onto the Ce-MOF and transformed to MF-CeO<sub>2</sub> [2–4]. As synthesized CeO<sub>2</sub>, MF-CeO<sub>2</sub> shows a favourable structural advantage with nanostructure morphology. The prepared Ce-MOF, CeO<sub>2</sub> and MF-CeO<sub>2</sub> are confirmed via various physicochemical characterizations such as XRD, FE-SEM, HR-TEM and XPS. The fabricated Ce-MOF and CeO<sub>2</sub> show discharge/charge capacities 247/100 mAh g<sup>-1</sup> and 279/147 mAh g<sup>-1</sup> in the initial cycle with 40.6% and 52.6% coulombic efficiency (CE), followed by upon charge-discharge process over 250 cycles shows with no more fading the reversible specific capacities about 106/105 mAh g<sup>-1</sup> and 109/108 mAh g<sup>-1</sup> with 99% and 99.2% CE respectively, at the current rate of 1C. In addition, it shows good reversible capacity at a low current rate of 0.1C. Thus, it could be one of the sustainable candidates as anode materials for LIBs and their electrochemical behaviors investigated in detail and compared briefly with one another. However, in the best of knowledge, no one documented that the recycled TPA is utilized for the preparation of Ce-MOF, CeO<sub>2</sub> and MF-CeO<sub>2</sub>. The archived remarkable electrochemical performance is the potential key to renovate economic approaches and large-scale productions for the energy storage device. It could be one of the most effective approaches to recycle PET bottle waste into long-term energy storage applications in a PET-free environment in the future.</p> Lakshmanan Kumaresan Copyright (c) 2021 Lakshmanan Kumaresan 2021-09-20 2021-09-20 1 01 Advances in the Synthesis and Thermoelectric Applications of Metal Chalcogenide Nanomaterials https://spast.org/techrep/article/view/1920 <p>With advancing technology, rise in energy demand is an alarming concern and providing an alternative source &amp; replenishing existing energy sources shows a promising pathway for a sustainable future. Thermoelectricity is a phenomenon of conversion of thermal energy into electricity. Thermoelectric materials are capable of converting the waste heat, which accounts to 2/3rd of energy available, to electricity that can be used for different purposes. Understanding their role in the field of energy supply, thermoelectric materials and devices have been extensively explored and studied.<br>In this review, we have presented recent advances in preparation of metal selenides, metal tellurides and layered metal oxychalcogenides by various methods for diverse applications such as (Wearable Devices, Thermoelectric generator, Wireless Sensors, etc.,) owing to their unique characteristics. We have also discussed the enhancement methods studied for improving electrical conductivity, Seebeck coefficient and thermal conductivity of these materials at nanoscale dimension and its effect on their thermoelectric efficiency. Finally, we have explored the various notable progresses in thermoelectric device application in enormous fields that are advantageous in overcoming the wastage of energy in the form of heat and have thrown light upon the scope of future prospects. Thus, this article is credited to cover recent advances in metal chalcogenide compounds with thermoelectric properties and scope for further research.</p> Yashaswini N Suraj L Sachith Nayak Copyright (c) 2021 Yashaswini N, Suraj L, Sachith Nayak 2021-10-09 2021-10-09 1 01 Artificial Intelligence Applications in Renewable Energy systems https://spast.org/techrep/article/view/1492 <p>In recent years, carbon emissions and demand for energy have improved dramatically around the world due to the increasing population and energy-consuming devices. The integration of renewable energy resources into an electricity system offers an efficient solution in terms of low-cost energy consumption with lower carbon emissions. However, renewable energy sources such as solar panels have an unreliable nature in power generation due to their dependence on weather circumstances, such as solar radiation, temperature, and humidity. Thus, to challenge this irregular nature of solar power energy, a power forecast is essential for efficient energy management. So, in order to improve the prediction ability of renewable energy sources, several prediction methods have been established. Novel technologies like artificial intelligence (AI) and machine learning (ML) proposals a lot of chances to address these problems. Basically, artificial intelligence (AI) technology has gone through fast growth during the past several years, and in modern industrial systems, their applications have increased quickly. The main objective of this paper is to explain how the artificial intelligence (AI) method might play a significant role in modeling and predicting renewable energy systems. At the beginning of the paper, the basic features of artificial intelligence that are related to renewable energy applications have been studied. Secondly, analyses the applications of machine learning in various areas of renewable energy systems like forecasting where machine learning is used to build precise models, Maximum Power Point Tracking (MPPT) where machine learning provides smooth control and robust, inverter where machine learning (ML) can be used to offer high excellence power without variation even when input is irregular. At the end of this paper, opportunities and future challenges of artificial intelligence (AI) for renewable energy sources are provided.</p> Durga priyanka kodada Copyright (c) 2021 Durga priyanka kodada 2021-10-08 2021-10-08 1 01 Global Offshore Wind Scenario: A Review https://spast.org/techrep/article/view/822 <p>This paper is a concentrated culmination of the past and the current trends in the development of offshore wind farms (OWFs) all around the major industrial and economic regions of the globe. Humankind has witnessed the aggrandization of technological wealth throughout the world, since the era of the industrial revolution, which dates back to the years 1760 to 1820; and since then, there is no looking back. Industries, technological developments have surged to levels and capacities that the human race would not have fathomed to imagine a decade or two back. Every single piece of machinery built was conceived and burdened with the purpose of making the common man’s life easier, to reduce his efforts. But little did we know, that greed would clasp us all in its herculean grip, driving us all to create more and more of such machines and industries, without giving a second of thought about the inimical effects it would have on the different ecosystems or the environment as a whole. We, as a civilized humankind, need to open up our minds and think with a broader perspective about the environment, and make sure we do not destroy this planet, even before our upcoming generations get to see the face of it.&nbsp;</p> <p>One of the major contributors to global pollution and global warming is the power generating industry, which as of today, mainly focuses on fossil fuel - based generation; and as a consequence of this, staggering amounts of toxic fumes and pollutants are generated. According to the Union of Concerned Scientists, in an average year, a typical coal plant (500 MWs) generates 3.7 million tons of carbon dioxide, an amount equivalent to chopping down 161 million trees [1]. Now these numbers look alarming, if analysed using the world as a parameter, because the above numbers pertain to just the USA, whilst there are around 62,500 active power plants all around the world, which result in a cumulative generation of trillions of tonnes of greenhouse gases and pollutants [2]. So in order to curb the pollution caused as a result of power generation by the usage of fossil fuels, a cleaner, greener alternative has to enter the picture; and the viable options are solar, wind, hydro, geothermal and biomass facilitated power generation. Amongst the aforementioned sources of renewable energy, wind has proved to be the most rapidly growing source, all across the world. As depicted in pie chart (Fig. 1) below, 721 GWs of wind power was consumed globally in the year 2020; the highest among all renewable energy sources [3].</p> <p>But this is just the beginning, as the global consumption of electric power is gigantic as compared to mere 721 GWs and has amounted to a massive 3 trillion watts, which is only set to increase by almost 80% by the year 2050, as industrialization and developments are on a steep upward rising curve [4].</p> <p><img src="https://spast.org/public/site/images/kaushalhote0204/1.jpg" alt="" width="536" height="258"></p> <p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</p> <p><strong>Fig. 1.</strong> Global power consumption for various renewable sources (in GWs)</p> <p>&nbsp;</p> <p>In this review article, the past and the current trends in the development of offshore wind farms (OWFs) all around the major industrial and economic regions of the globe like Asia, Europe, Middle East and Africa, South America and the USA are discussed. Along with the aforementioned sections, detailed reviews pertaining to wind turbine technologies which describe the current industry standard for the OWF industry and the latest technologies which are trending in the market are also highlighted. Also, the recent developments in transmission, grid and power electronic converter technologies which essentially comprise the bridge between an offshore unit and an onshore grid and have MMC (Modular Multilevel Converter) and OWF models [5], MMC-HVDC models [6], VSC-HVDC (Voltage Source Converter based High Voltage Direct Current) power grids [7],&nbsp;have been elaborated. A detailed life cycle assessment review which encompasses the overall lifespan and quality assessments of the machinery used in OWFs, in particular, the Vestas' 2-MW GridStreamer<sup>TM</sup> wind turbines [8] as well as locally manufactured small wind turbines and pico-hydro plants [9]. In addition, the successive section reviews the work which describes &nbsp; second generation high-temperature superconductor synchronous generators with direct-drive technology as a better substitute for permanent-magnet direct-drive synchronous generators [10]. In the end, an overall economic and cost analysis of the wind turbines used in the industry, which provides an insight to the wind turbine markets and the current statistics has been enumerated.</p> <p>Considering the bigger perspective for this work, this study can serve as a base-repository of all the current trends and scenarios for all the upcoming/ongoing projects in the sector of OWFs and harnessing power through wind energy in general. The main objectives which would be served via this review are as follows:</p> <ol> <li>To analyse the current scenario of OWFs in the major economical parts of the world.</li> <li>To assess the current&nbsp;wind turbine technology in the market.</li> </ol> <ul> <li>To enumerate on the transmission, grid and power electronic converter technologies.</li> </ul> <ol> <li>To perform the life cycle assessment and economics of wind turbines.</li> </ol> <p>The prime aim of this study is to contribute to ameliorate the quality of the common man’s life by emphasizing on the benefits of offshore wind. If implemented with the correct vision, offshore wind has the potential to cater to the energy demands of the entire planet [11], resulting in a steep decline in the usage of fossil fuels to generate electricity; as rightfully highlighted in the graph (Fig. 2) below, which shows the amount of total offshore wind installations in the year 2020 as compared to 2019.&nbsp;</p> <p><img src="https://spast.org/public/site/images/kaushalhote0204/2.jpg" alt="" width="924" height="650"></p> <p><strong>Fig. 2.</strong> Total installations of offshore wind turbines in 2019 and 2020&nbsp;</p> <p>&nbsp;</p> <p>In conclusion, emphasis is laid on the importance of snubbing fossil fuels and substituting them with offshore wind assisted power generation. With this, the environment can be deemed safer; and ecosystems can once again breed and breathe freely.</p> Kaushal Hote Riya Kaushik Washima Tasnin Copyright (c) 2021 Kaushal Hote, Riya Kaushik, Dr. Washima Tasnin 2021-09-16 2021-09-16 1 01 Role and Improvements of Battery Energy Storage Systems in Energy Sector https://spast.org/techrep/article/view/364 <div class="page" title="Page 1"> <div class="layoutArea"> <div class="column"> <p>The field of battery and energy storage has seen a significant growth in the past five decades through the invention of Lithium Ion cells and their potential for storing excess energy for back up purposes. [1] This paper would focus on the development of Battery Energy Storage Systems (BESS) and the implementation of BESS in the field of energy storage in microgrid in peak shaving algorithm , load shedding etc. This paper also provides an introduction to modelling of battery charge controller and power conditioning component for successful integration of BESS into microgrid for maintaining the fundamental requirements such as nominal frequency, voltage, low harmonics and comparatively lower negative sequence from the BESS. [2-4] On the other hand the paper would provide the methodology and simulated results of various scenarios considering the renewable energy , BESS and grid for automated load management. The paper provides a comparative result of absence of BESS in a microgrid and the effect in presence of BESS for a microgrid and peak demand reduction on the grid. [5-7]</p> </div> </div> </div> Viswanathan Ganesh Ajay Krishna V.M Senthilmurugan S Copyright (c) 2021 Viswanathan Ganesh, Ajay Krishna, S.Senthilmurugan 2021-09-14 2021-09-14 1 01 The Electrochemical Investigation of BixNiyOz/ Bi2O3 nanostructured Active electrode for the energy storage application https://spast.org/techrep/article/view/1980 <p><strong>Abstract </strong></p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Energy has become an integral part of human life. Hence energy research set off new challenges to the researchers. Since energy storage is an indispensable part of this journey, devices like supercapacitors and batteries have been attracting growing interest in energy-storage applications for the past decade. [1] A supercapacitor is an alternative that evinces the potential to emulate future energy technologies. To achieve this decisive task, metal oxides can be the potential electrode material. [2] Transition-metal oxides offer a fast and reversible surface redox reaction with higher specific capacitance (SC) and are frequently preferred in commercial energy storage products.&nbsp; But low stability, poor conductivity, and limited rate capability are the demerits associated with it. Reducing the demerits and improving the performance mixing of two or more metal oxides is a modern approach in metal oxides. Many studies have been reported on binary metal oxides, i.e., Bismuth molybdate (Bi2MoO6),[3] CoMoO4,[4] NiMoO4, [5], etc. Among these, bismuth nickel compounds are less studied and not reported for energy storage appliaction. Bismuth and nickel are considered the best anode material due to their low cost, less toxic, and environment-friendly properties. [6]</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; In this study, we synthesized bismuth, nickel-based oxide material by simple and most versatile hydrothermal synthesis method, as shown in fig.1 A. Where 1:1 M solutions of bismuth nitrate (Bi (NO<sub>3</sub>)<sub>3</sub>) and Nickel Nitrate (Ni (NO<sub>3</sub>)<sub>2</sub>) were used as starting material, and an appropriate amount of polyvinylpyrrolidone (PVP) was used as a caping agent along with urea and prepared homogeneous solution. Then the resultant solution is transferred to the 100ml Teflon autoclave and set the reaction for 12 h at the desired temperature. The final sample is further annealed at 400°C temperature for 2 hours. As prepared binary nanocomposite grown on nickel foam was systematically characterized using techniques viz XRD, HRTEM, FESEM, XPS, EDS, etc. From FESEM images, it is observed that the material possesses particle and sheet-like morphonology, which gives high surface area and provides an active site for a redox reaction; XRD study shows the sharp and broader peaks which confirm the crystalline structure of the material. Whereas electrochemical characterization viz cyclic voltammetry (CV) was measured in 6 M KOH at various scan rates for the potential window of -0.2V to 0.8V as depicted in fig.1B from the CV curve, we can confirm the pseudocapacitive behaviour of the material , along with it galvanic charging-discharging (GCD) test were performed and he areal capacitance of 137.7 mF/cm<sup>2</sup> was achieved at 1 mA/cm<sup>2 </sup>current density with the energy density of 4.7 × 10<sup>-3</sup> Wh/cm<sup>2</sup> and 138.8× 10<sup>-3 </sup>W/cm<sup>2</sup> power density. The stability of the electrode is observed over the 5000 charge-discharge cycles at 2 mA/cm<sup>2 </sup>current density. To assess the electrochemical performance of the device, electrochemical impedance spectroscopy (EIS) was implemented. Overall the bismuth nickel nanocomposite shows the well-suited characteristics for supercapacitor devices and it can be potential electrode material for the future storage device.</p> Yogesh Nakate Umesh Nakate ‪Rafiq Ahmad Copyright (c) 2021 Yogesh Nakate, Umesh T Nakate, ‪Rafiq Ahmad 2021-10-09 2021-10-09 1 01 Renewable Energy Sources – A Review https://spast.org/techrep/article/view/555 <p><span style="font-weight: 400;">The development of technology combined with the surge in population has led to a new era of living that has increased energy demand. Fossil fuel has been the main energy source for so many years, but it is no longer sustainable with its depletion and negative consequences. A need has arisen for a replacement resource to replace the depleting fossil fuels using right now. This need is what pushes us towards renewable energy. An examination of renewable energy sources: their uses, potentials, and limitations, as well as their effects on the climate and human health, is presented in this work. As final recommendations, the paper outlines policies and strategies to address climate change and fully integrate renewables as a sustainable energy source. Renewable energy means collecting energy from natural resources that are replenished over time, like sunlight, wind, tides, waves, etc. Fossil fuels, on the other hand, are being used far faster than they are being replenished. While the majority of renewable energy is considered sustainable, there are some that are not, for instance some biomass. &nbsp; &nbsp; In addition to their major advantages, renewable energy sources also have some disadvantages. The initial setup costs are very high. High storage costs pose a problem for storing energy. Renewable energy is dependent on weather conditions that may be unpredictable, causing energy shortages. There is a need for a large area for installing renewable energy technologies.</span></p> <p><span style="font-weight: 400;">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Fossil fuels are depleting gradually and negatively impacting the environment. Switching to renewable energy sources is necessary to limit their negative impact. These are the energy sources that do not deplete with time and provide nearly unlimited energy According to EPA (Environmental Protection Agency), 65% of total greenhouse gas is carbon dioxide (CO2) emission that comes from fossil fuels. Among the key factors in reducing our dependence on fossil fuels in recent years is renewable energy. Shortly, renewable energy sources will grow rapidly and will potentially become the primary source of energy, reducing over-dependence on fossil fuel. Wind energy is the use of wind to provide electric power using a wind turbine to turn generators.</span></p> Rohan Kandpal Rajendra Singh Copyright (c) 2021 Udit Mamodiya 2021-09-15 2021-09-15 1 01 High Water-Oxidation Catalytic Activity of FeNi-Layered Double-Hydroxide Nanoflakes on Carbon Paper https://spast.org/techrep/article/view/151 <p><strong>Introduction</strong>: A water-based electrochemical system (WES) is attracting attention as an innovative technology for overcoming the global-warming and fossil-fuel crises. Water-based electrochemical reactions smoothly occur by using various catalysts. And then, their reactions are designed, proceeding on a gas-diffusion electrode (GDE) working on three-phase boundaries of gas//liquid//solid interfaces.</p> <p>&nbsp; Oxygen evolution reaction (OER), 4-electron oxidation of two water molecules [1], is indispensable for the construction of WES combined with electrochemical reductions (ORR and CO<sub>2</sub>RR) of the ubiquitous gases O<sub>2</sub> and CO<sub>2</sub> (Fig. 1). Toward the development of alternative catalysts using rare metals such as Pr and Ir, advanced catalysts composed of earth-abundant and low-cost 3d transition metals have comprehensively explored. FeNi-layered double hydroxides (LDHs) of binary metal OER catalysts are benchmark materials, where a synergistic mechanism via the binary metal atoms [2,3]. Note that inherent catalytic activities can be totally evaluated based on four parameters of overpotential, Tafel slope, turnover frequency, and mass activity [4].</p> <p>Here, we aimed to prepare nanoparticulate OER catalysts composed of FeNi-based hydroxides via FeNi-Prussian blue analog (FeNi-PBA, Fe<sub>1-<em>x</em></sub>Ni<em><sub>x</sub></em>[Fe(CN)<sub>6</sub>]<sub>0.67</sub>), whose metal composition ratios are systematically controlled. Carbon paper (CP) is a commercially available GDE, employed for the deposition of the nanoparticulate OER catalysts.</p> <p><strong>Experimental section</strong>: FeNi-PBA nanoparticles (NPs) were synthesized by mixing of an aqueous mixture of FeSO<sub>4</sub>·7H<sub>2</sub>O and Ni(NO<sub>3</sub>)<sub>2</sub>·6H<sub>2</sub>O and an aqueous solution of K<sub>3</sub>[Fe(CN)<sub>6</sub>] in difference metal composition ration of&nbsp; <em>x</em> = 0, 0.1, 0.2, 0.4, 0.6, 0.8, 0.9, and 1 of Fe<sub>1-<em>x</em></sub>Ni<em><sub>x</sub></em>[Fe(CN)<sub>6</sub>]<sub>0.67</sub> [5]. FeNi-PBAs were hydrolyzed to Fe<sub>1-<em>x</em></sub>Ni<em><sub>x</sub></em>OH. For control microgram-scale mass-loading amounts of catalysts, we prepared FeNi-PBA NP aqueous dispersion solutions via surface modification of [Fe(CN)<sub>6</sub>]<sup>4</sup><sup>-</sup>, and the as-prepared solutions were drop-casted on CP. After the hydrolysis in a KOH solution, OER activities were measured in an alkali condition using the three-electrode method.</p> <p><strong>Results and discussion</strong>: FeNi-PBA NP solids were decomposed to Fe<sub>1-<em>x</em></sub>Ni<em><sub>x</sub></em>OH with release of [Fe(CN)<sub>6</sub>]<sup>n</sup><sup>-</sup> in a KOH solution from X-ray diffraction (XRD) patterns, FT-IR spectra, and X-ray fluorescence analyses. In <em>x</em> = 0.4 – 0.8, the FeNi-PBA NPs was transformed to FeNi-layered double hydroxide (FeNi-LDH) nanoflakes with sheet-domain sizes between 10 and 20 nm (Fig. 2a).</p> <p>A surface-modified FeNi PBA NPs immobilized on CP were directly transformed to Fe<sub>1-<em>x</em></sub>Ni<em><sub>x</sub></em>OH by a similar hydrolysis reaction, based on X-ray photoelectron spectroscopy (XPS). The OER overpotentials, <em>η</em><sub>10</sub>, normalized at a catalytic current of 10 mA cm<sup>−2</sup> were minimized in the case of FeNi-LDH nanoflakes (<em>x</em> = 0.6). Depending on loading amounts of FeNi-PBA (= FeNi-LDH), the OER overpotentials were changed. In an optimized condition, the <em>iR</em>-corrected OER overpotential of FeNi-LDH (<em>x</em> = 0.6)&nbsp; was estimated to be <em>η</em><sub>10</sub> = 269 mV. To the best of our knowledge, the as-prepared FeNi-LDH nanoflake immobilized on CP showed the highest OER activities based on the lowest Tafel slope (15.1 mV dec<sup>−</sup><sup>1</sup>) and the highest values of turnover frequency (1.58 s<sup>−</sup><sup>1</sup>) and mass activity (10,600 A g<sup>−</sup><sup>1</sup>) at a low overpotential of 300 mV (Fig.2b) [6]. The inherently high catalytic activity is derived from the downsizing effect of a sheet dimension (= increasing OER-active sites of FeNi-LDHs) and the controlled microgram-scale mass loading procedure of FeNi-LDH nanoflakes (= inhibition of catalyst aggregation).</p> Manabu Ishizaki Copyright (c) 2021 Manabu Ishizaki 2021-09-08 2021-09-08 1 01 Electrochemical performance and fabrication of different Polyaniline (PANI) morphologies as supercapacitor electrodes https://spast.org/techrep/article/view/2559 <p>We develop and fabricate different morphologies of Polyaniline (PANI) viz., granular (Fig. 1a), pebbles (Fig. 1b), spheres (Fig. 1c), tubes (Fig. 1d), fibres (Fig. 1e) and flakes (Fig.1f) via two methods: chemical polymerization method and self-assembled method of polymerization of Aniline monomer. The synthesis process is carried out in the presence of dopants, Hydrochloric Acid (HCl), Ammonium persulfate (APS) as an oxidant and Triton X-100 as a surfactant to form PANI morphologies. The as-synthesized PANI samples are characterized for surface morphology via Field Emission Scanning Electron Microscopy (FE-SEM), electronic transition information within the PANI chain network via UV-Vis spectroscopy, band and functional groups information via Fourier Transform Infra-red spectroscopy (FTIR), phase structure, crystallinity, amorphous nature determined via X-ray diffraction (XRD) and thermal stability via Thermogravimetric analysis (TGA). Raman analysis reveals the amorphous nature of the PANI structures. All the results obtained from above characterization techniques confirm the formation of the PANI fabrication. PANI is one of the most important kind of conducting polymers that has been playing a tremendous role in the energy storage devices. PANI has become a research corner for supercapacitor electrode material due to low cost of aniline monomer, facile synthesis, environmental stability and high specific pseudocapacitance values and it alone can be used in electrode materials [1]. It solves the problems related with specific capacitance of pseudocapacitance but cycling performance is poor.</p> <p>For fabrication of PANI electrodes, acetylene black is used as conducting agent and PVDF used as binding material to form active materials. They are pasted onto the graphite sheet as a current collector and tested as a supercapacitor electrodes performances in aqueous acidic electrolytes 0.1M H<sub>2</sub>SO<sub>4</sub> and gel polymer electrolytes (PVA/H<sub>2</sub>SO<sub>4</sub>) using Cyclic Voltammetry (CV), Galvanostatic charge/discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) analysis. They evaluate the sustainability of the PANI electrodes for supercapacitor application.</p> <p>It is seen that as the aniline monomer concentration, temperature and time of stirring changes, the electrochemical properties of the material changes significantly due to the different morphologies. It is analysed that PANI with different morphologies having different specific capacitance are mainly governed by the synthesis and its conditions. The fabricated electrode materials exhibits good specific capacitance, rate performances, long cycle stability in polymer gel electrolytes PVA/H<sub>2</sub>SO<sub>4</sub> instead of the acidic electrolyte H<sub>2</sub>SO<sub>4</sub>. The development and fabrication of different morphologies based PANI [2] as perspective electrode material enhances the electrochemical properties and provides a feasible route for promoting the applications in supercapacitor for the future generation.</p> <p><img src="https://spast.org/public/site/images/editorchief/mceclip0.png"></p> Gyan Singh Yogesh Kumar Samina Husain Copyright (c) 2021 Gyan Singh, Yogesh Kumar, Samina Husain 2021-10-17 2021-10-17 1 01 Design and Development of Li-ion Batteries for Electric Motorcycle https://spast.org/techrep/article/view/2654 <p>Battery technology has evolved since the introduction of Li-ion batteries in 1976. While Li ion batteries were primarily created for portable electronics they are now used in a growing number of applications such as electric vehicles, drones, satellites, smart watches, power tools, medical equipment and even utility scale storage. Many Li-ion batteries have developed since then have specific advantages and disadvantages over other types. In this review paper, we discuss the design development timeline of Li-ion cells and the technical advancements in the materials used for making the cathodes and anodes suitable for the Electric Vehicle industry (EV) [1]. With the rise of sustainable development, the world has shifted towards manufacturing of Electric Vehicles. Electric vehicles play an important role in reducing the use of fossil fuels like petroleum and diesel such as in combustion vehicles, as these are powered by Li ion batteries which reduce the greenhouse gas emission of earth.[2]. With the increase in demand of 2 wheelers, the requirement for a proper battery pack is of immense importance. Different types of Li ion cells possess different battery chemistry thus providing different applications. Electric-motorcycles or motorbikes have been known to use various types of cells starting from LCO to NMC to NCA to LiPo and now LFPs. The battery pack of electric-motorcycles are generally classified on the basis of their performance into energy dense and power dense packs. This paper covers the procedure for selecting cells to manufacture a battery pack based on energy and power requirements. Various factors affect the overall life of a battery pack and to maximise its life, the vehicle needs to run at optimum requirements such as its C-rate, SOC and Depth of Discharge etc. This paper will help researchers and engineers who are already working in this industry as well as the new scientists who are willing to join the EV industry get a broader and wider look on the importance of battery chemistry in assembling a battery pack. This review paper emphasises on the prospects of building a battery module for an electric motorcycle.</p> Mohammed Dilshaad Uzair Saksham Mamtani B.H.S. Thimmappa Copyright (c) 2021 Mohammed Dilshaad Uzair, Saksham Mamtani, B.H.S. Thimmappa 2021-10-17 2021-10-17 1 01 Electrochemical studies on Polyaniline/Titanium oxide composite for aqueous supercapacitors https://spast.org/techrep/article/view/1960 <p>Over the couple of decades, Supercapacitors (SCs) attracted tremendous attention of researchers among all energy storage systems due to its high-power density, long cycle life, and fast charge-discharge rates [1]. Development on SCs is dependent on electrode materials which play an important role in the energy storage [2]. Polyaniline (PANI) has been widely studied as electrode material because of its high conductivity, low cost, and easy synthesis [3]. However, poor cyclic stability becomes a major obstacle for pristine PANI to be used in supercapacitors. Poor cyclic stability is minimized by doping PANI with inorganic materials like TiO<sub>2</sub> which also improves the mechanical stability [4,5]. The Polyaniline (PANI) and Polyaniline - Titanium dioxide (PANI-TiO<sub>2</sub>) nanocomposites were prepared by interfacial polymerization using ammonium persulfate (APS) as oxidant. The physico-chemical properties were studied using P-XRD (powder X-ray diffraction), SEM (scanning electron microscopy), HR-TEM (high-resolution transmission electron microscope) and FT-IR (Fourier transform infrared spectroscopy). The XRD patterns of PANI and PANI-TiO<sub>2</sub> nanocomposites were given in fig.1 (A) and it is observed that PANI has a broad band at 25 degree and Titanium dioxide has many prominent peaks which were consistent with the JCPDS file (4-0477). These results of PANI-TiO<sub>2</sub> nanocomposite confirmed the presence of TiO<sub>2</sub> in PANI matrix. The intensity of peaks in nanocomposite decreased as expected due to the presence of PANI. The TEM image was shown as inset in fig.1 (A). It is observed that, PANI was wrapped around TiO<sub>2</sub> particles and TiO<sub>2</sub> particles were well dispersed in PANI matrix.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; To analyse the electrochemical behaviour of the PANI and PANI/TiO<sub>2</sub> nanocomposites, Cyclic voltammetry (CV), Galvanostatic Charging and Discharging (GCD), and electrochemical impedance spectroscopic (EIS) measurements were employed using CHI 608E electrochemical workstation at room temperature. The electrochemical measurements were conducted in a three-electrode system consisting of toray carbon paper coated with active material as a working electrode, saturated calomel electrode as a reference electrode, and platinum wire as a counter electrode in 1 M KOH solution. CV responses were recorded using cyclic voltammetry at different scan rates and charge-discharge curves were recorded using chronopotentiometry at different current densities. The CV responses and discharge curves of PANI and PANI-TiO<sub>2</sub> were shown in fig.1 (B) and fig.1 (C) respectively. The PANI-TiO<sub>2</sub> nanocomposites exhibited maximum specific capacitance (Cs) of 1456 F/g at a scan rate of 5 mV/s and 536 F/g at a current density of 5 A/g. These nanocomposites also delivered a maximum energy density (ED) of 8 W h Kg<sup>-1</sup> at a corresponding power density (PD) of 598 W kg<sup>-1</sup>. A higher solution resistance (R<sub>s</sub>-1.49 Ω) and lower charge transfer resistance (R<sub>ct</sub>-0.33 Ω) were observed in PANI-TiO<sub>2</sub> nanocomposites. Symmetric supercapacitor prototype (fig.1(D)) was fabricated using two electrodes coated with PANI-TiO<sub>2</sub> nanocomposites and electrically isolated from each other by porous membrane pre–soaked with the electrolyte solution. The device achieved specific capacitance of 145 F/g and 46 F/g at 5 mV/s and 2.5 A/g. The outstanding capacitive retention of 70% after 2000 cycles in device can enable the PANI/TiO<sub>2</sub> hybrid composites to be a promising electrode material for future generation energy storage.</p> <table> <tbody> <tr> <td width="258"> <table> <tbody> <tr> <td width="21">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> <p><br><strong>A</strong></p> </td> <td width="265"> <table> <tbody> <tr> <td width="169">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> <p><br><strong>B</strong></p> </td> </tr> <tr> <td width="258"> <table> <tbody> <tr> <td width="16">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> <p><br><strong>C</strong></p> </td> <td width="265"> <table> <tbody> <tr> <td width="163">&nbsp;</td> </tr> <tr> <td>&nbsp;</td> <td>&nbsp;</td> </tr> </tbody> </table> <p><br><strong>D</strong></p> </td> </tr> </tbody> </table> <p><strong>&nbsp;</strong></p> <p><strong>Fig.1.</strong> (A) XRD patterns of PANI, PANI-TiO<sub>2</sub>, TiO<sub>2</sub> (inset-TEM image of PANI-TiO<sub>2</sub> nanocomposite), (B) CV patterns of PANI and PANI-TiO<sub>2</sub> nanocomposite, (C) Charge-discharge curves of PANI and PANI-TiO<sub>2</sub> nanocomposite, (D) Plot of capacitance retention of PANI-TiO<sub>2</sub> nanocomposite.</p> Radhika Rao Rudranna Nandihalli Sudha Kamath M K Copyright (c) 2021 Radhika Rao, Rudranna Nandihalli, Sudha Kamath M K 2021-10-08 2021-10-08 1 01 Ta2O5-rGO nanocomposite as emerging anode material for sodium ion storage via extrinsic pseudocapacitive redox process https://spast.org/techrep/article/view/646 <p>Abstract</p> <p>Metal oxide nanoparticles finds diverse application including energy storage [1-2]. Ta<sub>2</sub>O<sub>5</sub> nanoparticles are an emerging conversion type anode material [3-4], which store sodium ion via extrinsic pseudocapacitance property. Ionic liquid assisted hydrothermal methods have been employed to synthesise Ta<sub>2</sub>O<sub>5</sub> nanoparticles followed by hydrothermal method to synthesize Ta<sub>2</sub>O<sub>5</sub>–reduced graphene oxide (Ta<sub>2</sub>O<sub>5</sub>-rGO) nanocomposite.&nbsp; The Ta<sub>2</sub>O<sub>5</sub>–rGO nanocomposite delivered specific capacity of 19mAhg-1 after 500 cycles at 0.1C current rate compared to the pure Ta<sub>2</sub>O<sub>5 </sub>nanoparticles where it exhibited 18 mAhg<sup>-1</sup> after 150 cycles at 0.1C current rate. The stable electrochemical performance of Ta<sub>2</sub>O<sub>5</sub>–rGO nanocomposite could be offered by two-dimensional reduced graphene oxide possessing high surface area, better mechanical stability and high electrical conductivity enhances the electron and ion transfer rate. Finally, the present investigation urges contemporary researchers to design advance Ta<sub>2</sub>O<sub>5</sub>-rGO nanocomposites for sodium ion battery applications. Fig.1 shows the graphical abstract of the present work.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p>Key words: Ta<sub>2</sub>O<sub>5</sub>–rGO; nanocomposites; anode; conversion reaction; pseudocapacitance; sodium ion battery.</p> Nagaraju Ganganagappa Manukumar K N Harini R Copyright (c) 2021 Nagaraju Ganganagappa, Manukumar K N, Harini R 2021-09-19 2021-09-19 1 01 Tuning the tribological properties of Ni/NiO thin films by Nd:YAG pulsed laser irradiation https://spast.org/techrep/article/view/362 <p>Nickel (Ni) is one of the most common metal coatings used to synthesize composite <br>electrochemical coatings (CECs) as it is characterized by superior corrosion resistance, and <br>enhanced mechanical and tribological properties. Ni-based alloy coatings have been widely <br>used as wear materials [1]. The most employed Ni-based alloy coatings are NiFe, NiW, and <br>NiFeW. Ni, as the major element, provides ductility and enhances the corrosion resistance [2]. <br>These coatings are widely used in gas turbines and in oil and steel industries, where sliding <br>or erosion between one or more bodies is commonly encountered. Ni-based alloy coatings <br>may also be more suitable than Co-based alloy coatings due to their better antiwear properties <br>and lower costs. Recently, graphene has been used in the electrodeposition of Ni composite <br>coatings known as nickel-graphene (Ni–Gr) coatings for lubrication application. Such coatings <br>are superior in tribological properties as compared to other hard CECs that consist of <br>chromium, boron nitride, zirconium dioxide, PTFE, etc [3]. Similarly, NiO is a well-known <br>antiferromagnetic material, and a metal-deficient p-type semiconductor with a 3.6 eV band <br>gap. Nickel oxide (NiO) films have a wide range of applications due to their excellent chemical <br>stability. They have been used as catalysts, electrochromic display devices, fuel cells and gas <br>sensors. NiO thin films usually exhibit p-type conductivity due to holes generated by Ni <br>vacancies in the lattice and therefore NiO is an interesting candidate for materials research<br>[4]. Although structural and electrical properties of NiO films have been studied extensively, <br>mechanical and tribological properties have been recently trending primarily due its ease of <br>deposition. Therefore, understanding the correlations between the mechanical properties and<br>microstructure of NiO-based films has been of great interest. In particular, it has been widely <br>conceived that the wide variety of methods used for fabricating NiO thin films often resulted in <br>very different film microstructures or even stoichiometries.<br>The present work aims at investigating how the nanomechanical properties and the surface <br>wettability of the Ni/NiO thin films deposited on glass substrates by radio-frequency magnetron <br>sputtering change with the post-deposition laser irradiation. A semiconductor laser based on <br>Nd:YAG operating at its 4th harmonic wavelength, λ = 266nm with varying laser fluence and <br>spot size of about 5 µm is irradiated on the Ni/NiO film. The localized heating allows for <br>smoothening of the NiO film along with contributions to the changes in the stoichiometry of <br>NiO (reduction of excess oxygen) and creation of Ni interstitials. In particular, the effects of <br>tuning laser fluence and the subsequent evolution of films microstructure and the associated <br>nanomechanical properties of the Ni/NiO thin films revealed by the mechanical tests, wear <br>and coefficient of friction variations for tribological tests are discussed. The hardness (H) and <br>the elastic modulus (E) of NiO thin films are measured by nanoindentation and their <br>dependence on the laser fluence is studied. Raman analysis along with XRD analysis for structural changes due to laser irradiation and EDX were carried out to validate the <br>dependence of laser fluence on the hardness of Ni/NiO thin films due to interstitials/ reduced <br>oxygen</p> Srikanth Itapu BHANU SRI PILLA Vamsi Borra Copyright (c) 2021 srikanth itapu 2021-09-19 2021-09-19 1 01 Design and performance comparison of effect of different switching sources on thermoelectric energy harvesting using single-inductor boost converters https://spast.org/techrep/article/view/402 <p><span style="font-weight: 400;">This paper presents a comparison for the amount of power generated using different switching sources in a DC-DC boost converter designed to generate 3-5 V output voltage. The desired output voltage is sufficient to charge a rechargeable battery. The input voltage is supplied by a commercially available thermoelectric generator module (TEG) when subjected to appropriate temperature gradient. Three boost converter circuit configurations with gate pulse, square wave and PWM switching sources are designed to step-up the low DC voltage of 0.2 V from thermoelectric energy harvester. The output voltage and current levels are measured for estimating the amount of increase in output power. Gate pulsed switching in boost converter generated a highest output voltage of 5.26 V while square wave triggered circuit could generate maximum 3.5 V while PWM based switching generated an output voltage of 1.98 V for input supply of 0.2 V.</span></p> <p><span style="font-weight: 400;"><img src="https://spast.org/public/site/images/uditm/mceclip0.png"></span></p> <p><strong>Fig.1.</strong> <span style="font-weight: 400;">Basic Boost Converter</span><span style="font-weight: 400;">.</span></p> <p>&nbsp;</p> Deepshikha Yadav Copyright (c) 2021 Udit Mamodiya 2021-09-15 2021-09-15 1 01 Improvement in the performance of perovskite solar cells by reducing defect density with antisolvent treatment https://spast.org/techrep/article/view/2019 <p>Methylammonium lead (II) mixed halides (CH3NH3PbI3-xClx) have emerged as promising and efficient photoactive material owing to its excellent light absorption, low exciton binding energy, high carrier mobility and facile solution processability. Generally, vapour-assisted and two-step sequential deposition methods have been utilized for perovskite film formation for making efficient solar cells. The film qualities of perovskite photoactive layers like crystallinity, defect density, homogeneity, surface coverage, optical absorption etc. plays crucial role in the photovoltaic performance. Perovskite films deposited by conventional spin-coating methods generally have some pin-holes and randomly oriented fine grains with a poor substrate coverage. <br>In this work, we have investigated the influence of chlorobenzene antisolvent treatment on perovskite film formation in inverted planar perovskite solar cells. Herein, we report the formation of smooth, pin-hole free flat homogeneous perovskite film by one-step antisolvent induced crystallisation method for the device configuration of ITO/PEDOT:PSS/ CH3NH3PbI3 xClx/PC71BM/Al.. The process involves spin-coating of perovskite precursor followed by addition of antisolvent liquid (chlorobenzene) in the mid of the spin-coating process. This antisolvent treatment process has shown an effective way to improve the morphology of the perovskite film as well as photovoltaic performance of the PSCs. The significant superior photovoltaic performance has been obtained with antisolvent treated PSCs having average PCE ~ 11.5% as compared to conventional spin-coated planar PSCs with an average PCE ~ 8% as shown in Fig 1. <br>In order to investigate this enhanced photovoltaic performance in antisolvent assisted PSCs, systematic investigations using optical absorption, IPCE, electroluminescence (EL), electrochemical impedance spectroscopy (EIS), capacitance-voltage (C-V), XRD, and scanning electron microscopy (SEM) have been carried out. <br>An enhanced absorption in antisolvent treated films in 400-650 nm wavelength range was observed which was also supported by IPCE measurements. We studied the electroluminescence (EL) emission spectrum for distinguishing the recombination losses. Conventional PSCs showed an increased loss due to non-radiative recombination as compared to antisolvent treated PSCs. This increased recombination loss was confirmed with electrochemical impedance spectroscopy (EIS) and Mott-Schottky (MS) analysis. Capacitance-voltage (C-V) measurement using MS plot has been used for distinguishing the effects taking place in bulk of the active layer and those occurring at the interface of perovskite/ETL or HTL [1,2] . We found lower built-in potential (Vbi) of 0.77 V and higher defect density (N) of 24.6 x 1016 cm-3 for conventional planar PSCs as compared to antisolvent treated PSCs with Vbi ~ 1.135 V and N ~ 24.6 x 1016 cm-3 [3]. The higher defects exerts extra potential barrier and hinder the charge carrier’s extraction. It also induce trap-assisted recombination and reflects as lower Voc and PCE as in case of conventional PSCs. The lower trap density and higher Vbi results in lower non-radiative recombination which is beneficial to raise both the Voc and PCE for antisolvent PSCs. In EIS studies, we have found two signals in the form of arcs in Nyquist plot and in the form of peak in bode plot at 104-105 Hz and 1 Hz respectively. We found a good agreement between ideality factor (nid) determined by two different methods viz. Sun-Voc (extracted from J-V curves) and Sun-RHF (extracted from EIS). Ideality factor of 1.64 and 2.28 has found for antisolvent treated and conventional PSCs [4]. The higher nid confirms the increased recombination loss in conventional PSC. </p> Deeksha Gupta Copyright (c) 2021 Deeksha Gupta 2021-10-09 2021-10-09 1 01 Research Pathway of Rechargeable Batteries for 2030 https://spast.org/techrep/article/view/1433 <p>An increase in the dependency on energy has made it inevitable for the humankind to explore storage devices to harness the energy. This necessity has propelled the evolution of Batteries as energy storage devices. The high production of electronic gadgets, portable battery-powered equipment, and electric vehicles has led to the soaring demand for highly optimized and better performance battery systems. With the invention of Lithium-Ion Batteries (LIBs) in 1991 by Sony, the focus of the Industrial-centred research has shifted towards LIBs and improving its performance parameters such as energy density and cycle life with enhanced safety. Decades of research on the lithium-ion batteries by Nobel Prize awardee in the year 2019 and several other veterans across the planet. In order to protect the planet, the major focus has shifted towards creating sustainable and environmentally friendly electrode (anode &amp; cathode) and electrolyte materials for the e-mobility. The state-of-the-art of electrode materials are developed by optimization of design and process to improve the safety and improve the fast-charging capability with enhanced cycle life batteries for the e-transportation [1-6].</p> <p>To facilitate this, from the material perspective, authors &nbsp;improve the performance of the battery by adopting the feasibility of silicon-based composite, lithium metal-based anodes and nickel rich of the LNMC/LNCA cathode and exploring new electrolytes including the solid electrolyte for solid-state batteries for the industrial scalable system. Further, the exigent need for the extrusion of toxic and expensive elements such as Cobalt in the NMC based lithium-ion batteries to eliminate the range anxiety and fast charging to meet the consumer requirement. Further, the testing including the fast charging is often concern thermal stability that is jeopardizing safety of the LIBs and may be led to thermal runaway and explode under abuse operations which is more prone with organic solvent-based liquid electrolyte-based batteries.</p> <p>To improve the thermal stability of the liquid electrolyte-based LIBs, the designing of the battery components that is to replace liquid electrolyte with solid electrolyte and thereby lamenting the trade-offs of thermal runaway. The solid electrolyte based solid-state battery (SSBs)&nbsp;&nbsp; however face engineering challenges that is interfacial characteristics, intergranular cracking, and parasitic reactions on the surface of electrode are intensive research. In the present study attempted to surface treatment on the electrodes and adoption of additive manufacturing process are being explored to improve the superior performance with enhanced cycle life of the battery.&nbsp;</p> <p>From the battery system engineering perspective, we elucidate the electronic control and the thermal management of the battery management system (BMS). Active cell balancing through the efficient BMS protects the battery from overcharging, deep discharging, and thermal runaway.[7] With fervent research towards the LIBs for decades and extensive usage and even with the recycling of used LIBs from electric vehicles, the saturation of the lithium metal is around the corner. This hurls the research on the LIBs to be expensive. To lessen this effect, the focus should be shifted to accommodate other potential battery technologies such as Sodium-Sulphur, Aluminium-Sulphur, Magnesium-Sulphur, etc, are considerable alternative to the existing LIB technology and expected to would ease out the burden on the LIBs.&nbsp;</p> <p>This article critically presents the holistic information of the rechargeable batteries from the material perspective, designing of battery components, battery system engineering, and scope for the industry and research fraternity to go beyond LIBs (Fig. 1). With reports citing that by 2030, the sale of Electric Vehicles would expected to be peak on the road, as much as 30 million, it is pivotal to comprehensively understand these aspects to complement the development of a sustainable and superior battery technology.</p> Pardha Saradhi Maram Laxminarayana Patro Surfarazhussain Halkarni Tousif Khan Nizami Jasvinder Singh Venkateswarlu Manne Sujith Kalluri Copyright (c) 2021 Pardha Saradhi, Laxminarayana, Surfarazhussain, Tousif Khan , Jasvinder , Venkateswarlu, Sujith Kalluri 2021-10-07 2021-10-07 1 01 Theoretical Modeling and Fabrication of Conductor–Dielectric Triboelectric Nanogenerators (CD-TENG) https://spast.org/techrep/article/view/149 <p>With the growing Pandemic COVID Scenario, Human beings are surrounded with dozens of miniaturised wearable electronics and healthcare sensors. The potential requirements of mobile sensors are nano/micro power sources which are practically driven by conventional harmful chemical batteries for its stable operation. Cyclic time to time monitoring and replacement of tiny µpower batteries is quiet cost effective method. Therefore many scientists undergo research worldwide in order to develop low cost, high efficient alternate power source to serve the portable electronics in an eco-friendly approach. There comes an emerging novel Triboelectric nanogenerator (TENG) mechanical energy harvester sustainably powering flexible low power electronics such as smart watches, mobile phones, keypads, wireless smart toys, interfacing man-machine smart lighting control and security system etc., Triboelectric nanogenerator works on the principle of tribo-electrification and electrostatic induction mechanism[1]. It operates on four working modes namely contact-separation, sliding mode, freestanding mode and single electrode mode. Here we focus on conductor to dielectric sliding mode operation for smart toy application[2]. Though tribo-electrification is a well-known older technology, practical implementation for a real-time system not yet commercialised at the present-stage due to some of the Challenging factors. Design and Development of Conductor-Dielectric Triboelectric nanogenerator (CD-TENG) faces three important gaps to be investigated in detail to improve the triboelectric performance. First, Selection of stable and durable materials from triboelectric series is important to achieve figure of merit results. Secondly besides material selection, optimised structural surface morphologies by adopting accurate physical techniques such as spongy structure, grating structure, wavy structure also plays crucial role in output stability. Third designing energy storage system for TENG has to be deeply studied to promote their intelligence and miniaturization. The design of TENG clearly uses organic eco-friendly materials for harvesting bio-mechanical energy which avoid environmental hazards to society rather usage of harmful chemical batteries[3]. The main objective of this research mainly focuses on selection of suitable triboelectric materials by theoretical investigation and mathematical simulation using COMSOL. Then followed by fabrication and characterization to enhance the performance for smart toy application[4]. The organic dielectric material selected for this experimental work is PDMS (polydimethyl siloxane) and conductive metal chosen for sliding is copper. The simulated results and experimental methodology where shown in the circular chart below.</p> <p><strong>&nbsp;Keywords</strong></p> <p>CD-TENG, PDMS, miniaturization, COMSOL, Surface Morphologies, cost-effective, chemical batteries</p> V VIJAYALAKSHMI Copyright (c) 2021 V VIJAYALAKSHMI 2021-09-08 2021-09-08 1 01 Role of Carbon protected BiVO4 nanostructured photoanode with FeOOH/NiOOH OER catalyst for solar water splitting applications https://spast.org/techrep/article/view/1844 <p>Solar water splitting is the process of converting solar energy into hydrogen fuel. BiVO<sub>4</sub> is the best suited photoanode material for water oxidation/oxygen evolution reaction (OER) because of its availability, bandgap, low cost. However, the water oxidation kinetics reaction is really sluggish and stability also needs to be improved. The kinetics of the photoanode is improved by adding ultrathin FeOOH/NiOOH co-catalysts [1-2] by photo-assisted electrodeposition method. A thin-protective carbon layer deposited by simple carbonization process [3] improves the stability of the materials. In this work, we have prepared and characterized the photoanode consists of Mo-doped BiVO4 protected by a thin carbon layer with FeOOH/NiOOH co-catalysts. The optimized photoanodes (Mo-BiVO<sub>4</sub>/C/FeOOH/NiOOH) provided higher photocurrent density at water oxidation potential (1.23 V<sub>RHE</sub>) compared to bare BiVO<sub>4</sub> photoanode. The addition of thin carbon layer increases the surface area and protects the nanostructured photoanode. The PEC performance of optimized photoanodes have been improved in terms of stability and OER by addition of alternate carbon protective layer and FeOOH/NiOOH catalyst</p> S.R. Sitaaraman Copyright (c) 2021 S.R. Sitaaraman 2021-10-08 2021-10-08 1 01 Non-carbonous Ternary Transition Metal Oxide@Sulphur as a Cathode Material for Li-Sulphur Rechargeable Batteries https://spast.org/techrep/article/view/1879 <p>A most important challenge of the 21<sup>st</sup> century is to develop long lasting energy storage systems with high safety standards. It means developing energy storage device with higher capacity and prolonged cycle life. Conventional alkali metal-ion battery systems have energy density of ~ 400 Whkg<sup>-1</sup>. Whereas, the metal sulphur battery system has high energy density of ~ 2500 Whkg<sup>-1</sup>, due to the high theoretical specific capacity of sulphur (1675 mAhg<sup>-1</sup>).</p> <p>&nbsp;</p> <p>The objective of this work is to design a suitable transition metal oxide (TMO, TM = Mg, Mn, Ti) based sulphur cathode. The catholyte sulphur can be introduced into the TMO core for fabricating the lithium sulphur batteries to reduce the surface corrosion of the electrode materials. The main challenge of this work is to reduce the polysulphide shuttle effect between the electrodes, which is the main reason behind surface corrosion of anodic part and low coulombic efficiency. P2|O3 mixed phase of TMO has proven to deliver higher charge-discharge capacity in metal ion batteries [1]. The P2 and O3 denote the trigonal prismatic and elongated octahedra sites between the TMO, respectively. We have synthesized a ternary transition metal oxide which is MnMgTiO<sub>2</sub> (MTMO) by using hydrothermal method, where the P2 phase of MnO<sub>2</sub> is hypothesized to be of higher proportion with respect to O3 phase of MgO<sub>2</sub>. The O3 phase of MgO<sub>2</sub> would remarkably suppress the volume change with continuous charge-discharge process. This is because, a part of Mn<sup>4+</sup> ions get substituted by Mg<sup>2+</sup>, which in turn alleviates Jahn-Teller distortion. The layered transition metal oxide MTMO has been infused with sulphur by melt diffusion process. The addition of the sulphur catholyte would result in the formation of polythionate complex, which would deposit on the surface of MTMO cathode through thiosulphate linkage. As synthesized MTMO-S has been confirmed by various physical characterizations, then the material is utilized to fabricate a standard CR2032 coin cell, and electrochemical behaviour has been characterized in detail. Moreover, the MTMO-S exhibits good reversible capacity with stable cycling. Thus, the MTMO-S could be one of the materials in future for real energy storage applications to the emerging field lithium-sulphur batteries.</p> Sajan Raj Sasirajan Little Flower Kavibharathy Kasiviswanathan Lakshmanan Kumaresan Kumaran Vediappan Copyright (c) 2021 Sajan Raj Sasirajan Little Flower, Kavibharathy Kasiviswanathan, Lakshmanan Kumaresan, Kumaran Vediappan 2021-10-09 2021-10-09 1 01 Copper Cobalt based Sulfides as Binder-Free Electrodes towards Faradaic Supercapacitors https://spast.org/techrep/article/view/568 <p>The growth in civilization and technologies urges the betterment of everyday life in an environmentally and economically productive way, demands the improved energy storage system for transports, domestic and conventional usages.[1] Amid the various energy storage systems, Supercapacitors (SCs) clasp their unique platform owing to their fast charge-discharge, long cycling capability and low cost.[2] As the use of state-of-art carbon based SCs are suffering from lower energy densities, a new stream opens up with transition metal based electrode materials, which are highly conductive and redox active materials, termed faradaic electrodes, likely faradaic/pseudo SCs.[3] Researchers have examined different energy storage systems based on transition metal oxides, hydroxides, sulfides and nitrides, verified the fact that sulfides display superior electrode performances.[4] The lower electronegativity of sulphur and poor solubility of sulfides fetches the surface properties and structural defects, boosts the electrical conductivity, which accompanies improved capacity and rate capability behaviour of sulfide based materials.[5] The ameliorated charge storage properties have been reported by combining multiple metal species, owing to the synergistic electrochemical influence of both the metals in ternary metal electrodes with lower band gap and higher conductivity.[6]&nbsp; Until now, ternary metal based faradaic SCs have been described widely. However, the comparative study of spinel sulfide (AB<sub>2</sub>X<sub>4</sub>) and layer by layer sulfides (AX@BX) has been rarely reported. Furthermore, the structural advantages and morphological impacts including multivalent elements, crystallinity, multidimensional architecture, porosity and interconnected conductive channels of the transition series electrodes are the roots for improved charge storage phenomena.[7] Furthermore the binder free growth is highly prudent in order to subdue the conductivity and active surface area loss with electro inactive polymer binder.[8]&nbsp; The&nbsp; direct growth of copper cobaltite chalcogenides were designed and developed<em> viz</em> simple and economically effectual electrochemical route followed by the hydrothermal cation exchange process without altering the morphological features. The systematic synthetic approach provided spinel crystalline structured copper cobalt sulphide (CuCo<sub>2</sub>S<sub>4</sub>) through <em>in-situ</em> codeposition and copper sulphide/cobalt sulphide composite (CuS/Co<sub>2</sub>S) <em>viz</em> layer by layer deposition. The obtained HR-SEM explains the unique dendrite morphology of copper cobalt sulphide (CuCo<sub>2</sub>S<sub>4</sub>) with primary midrib followed by secondary and tertiary trunks. Whereas, CuS/Co<sub>2</sub>S govern distinct CuS dendrite covered with thin Co<sub>2</sub>S sheets homogenously. The superior electrochemical behaviour of spinel CuCo<sub>2</sub>S<sub>4 </sub>to CuS/Co<sub>2</sub>S was verified with Cyclic Voltammetry (CV) studies and Electrohemical Impedance Spectroscopy (EIS) analysis, specifies the role of microstructural effects on electrochemical properties. The specific crystalline and morphological advantages including multiple oxidation states, continuous conducting pathways, 3D network, and porous architecture substantially promote the electrical conductivity and electrochemical property of the electrode material. Furthermore, CuCo<sub>2</sub>S<sub>4 </sub>electrode material governed superior charge storage property in supercapacitor application with capacitive value of 966 to 676.8 C g<sup>-1</sup> at current density ranging from 10 to 40 A g<sup>-1 </sup>with 70.15 % retention value. Considering, CuS/Co<sub>2</sub>S contributed 157.1 and 109.56 C g<sup>-1</sup> at 10 and 40 A g<sup>-1</sup> current densities and 69.73 % retention. The promising faradaic behaviour of the as prepared material was attributed by the stable charge property at different applied current density as 10, 20, 30, 40 and 10 A g<sup>-1</sup> for 5000 cycles with 95.56 and 92.7 % capacitive retention for CuCo<sub>2</sub>S<sub>4 </sub>and CuS/Co<sub>2</sub>S electrodes, respectively. The real time charge storage behaviour of the proposing electrode material was analysed with two electrode device, constitutes of Ni foam based CuCo<sub>2</sub>S<sub>4 </sub>and Activated Carbon Electrode (CCS//ACE) with aqueous electrolyte (3 M KOH). The fabricated device delivered 63.87% retention at current densities from 10 to 40 A g<sup>-1 </sup>and capacitive values of 132.7 and 84.76 C g<sup>-1 </sup>respectively, at 10 and 40 A g<sup>-1</sup>. The device cycling capability was checked through GCD cycling for 5000 cycles at 40 A g<sup>-1 </sup>with 98.27 % capacitive retention. Thus, the present work strategically explains the role of crystalline nature and morphological effects on charge storage property and offers the exclusive platform for binder free ternary chalcogenide electrode for the development of faradaic SCs.</p> Amala George Copyright (c) 2021 Amala George 2021-09-16 2021-09-16 1 01 Investigation on the Effect of Nanofluid Diameter and Concentration on Nanofluid Solar Pond https://spast.org/techrep/article/view/1243 <p>Solar pond is one of the simplest types of solar collector that utilised its salinity gradient to store thermal energy at the bottom of the pond where the density is the highest. However, research found that the brine water solar pond might cause salinity pollution to the surrounding vegetation and ground water if there is no proper management. Hence, this study evaluates the usage of nanofluid to substitute brine water in solar pond and investigate the effect of nanoparticles size and concentration on the solar pond performance. Unlike brine water that can bring negative impacts to the land or surrounding vegetation, silicon dioxide (SiO2) is a non-toxic, natural compound that can even be found in a natural pond. According to Bakthavatchalam et al., Pourhoseini et al. and Joseph et al. [1-3], to utilize nanofluid in solar pond, the thermal efficiency is a key criterion for the solar collector performance evaluation, that is directly influenced by the photothermal properties of the nanofluid, which can be affected by the particle size and concentration. Nevertheless, no experimental study has been done regarding to the utilization of nanofluid for thermal storage medium in solar pond as in the literature review.</p> <p>This paper proposes an experimental approach to evaluate the nanofluid density gradient solar pond performance. The experiment utilizes the Silicon Dioxide (SiO2) nanofluid as the storage medium in solar pond by using SiO2 nanoparticles’ size range from 20 to 30nm, 60 to 70nm and 400nm, to create a density gradient. The SiO2 nanofluid was synthesised using the two-step method as shown in fig.1 with deionised water as the base fluid and the amount of SiO2 nanoparticles as calculated. The nanofluid prepare is then sent for Field Emission Scanning Electron Microscope (FESEM), Zeta Potential (ZP) and Thermogravimetric analysis (TGA) for characterisation.</p> <p>The investigation on the solar pond performance with different SiO2 nanofluid concentration and sizes has been conducted with the experimental setup validated with the salt density gradient solar pond as shown in fig.2. The validation of experiment set up is done with salt density gradient solar pond using NaCl solution of concentrations and compared the temperature profile of each layer with the simulation results of salt density gradient solar pond test rig from ANSYS Fluent (table 1). The experiment of the SiO2 nanofluid solar pond is conducted in two sets which are interested to find out the effect of nanoparticle size and nanoparticle concentration on the performance of density gradient nanofluid solar pond. The temperature profiles of the solar pond test rig are shown in fig.3. The results of 20~30nm SiO2 nanofluid solar pond temperature rise in Lower Convection Zone (LCZ) is higher than of 60~70nm SiO2 nanofluid solar pond by 2.33% while the temperature rise in LCZ of 0.12wt% nanofluid solar pond is greater than of 0.04wt%. The experiments showed that the rise in temperature in LCZ after 6 hours is higher with smaller nanoparticle size and higher nanofluid concentration.</p> <p>In conclusion, this paper proposed SiO2 nanofluid as a potential substitution of brine water in the density gradient solar pond that could enhanced the thermal performance of solar pond at the same time avoid salinity pollution to surrounding vegetation and ground water.</p> Shania Ying Ying Ting Kim Leong Liaw Jundika Candra Kurnia Copyright (c) 2021 Shania Ting Ying Ying, Kim Leong Liaw, Jundika Candra Kurnia 2021-09-30 2021-09-30 1 01 Monitoring State-of-charge of Lithium-Ion Battery with Diverse Series- Parallel Configuration using Particle Filter https://spast.org/techrep/article/view/611 <p>Lithium-ion battery packs are typically assembled into modules. These modules can be equipped with various series-parallel configurations [1]. SoC estimation is of critical importance to the reliability and safety of a battery pack. SoC Estimation for a battery pack assembly is of great interest [2]. Our work presents a method for estimating SOC for multi-cell assemblies [3]. In this work a feasible method for monitoring SoC is demonstrated by designing a circuit model in Simulink of three different configurations 3s2p (three in series and two in parallel), 3s3p (three in series and three in parallel) and 4s2p (four in series and two in parallel) using Particle Filter. In this model, a current source is attached to the battery in order to maintain and control the circuit balance which is further attached to the subsystem having SoC, previous state of SoC, SoC minimum, charge current and discharge current as input, working on a simple logic; which is connected to the bus selector for respective output in scope. Initially, lithium-ion cells are connected in 3s2p configuration and then we compared our results by adding one cells in parallel (3s3p) and then in series (4s2p) with the estimated SoC of 3s2p configuration. All the three configurations have been simulated in 0.5C and 1C discharging rate with 0.5C charging rate respectively. The circuit parameters are taken as function of SOC, for model accuracy, where PFs algorithm are used for proper estimation of SOC [4]. Rated capacity is kept at 40Ah, nominal voltage of 12.6V, temperature at 25<sup>0</sup>C, discharge current as 20A for 0.5C discharging rate and 40A for 1C discharging rate with 20A of charge current. Current, Voltage and SOC plot for different configuration has been evaluated. By comparing 3s2p and 4s2p configuration (Fig.1), it is observed that the SoC of both the configurations has slight difference in their charging and discharging time, that is, they almost overlap each other with the slope of 0.0133. Upon comparing 3s2p and 3s3p configuration (as shown in Fig.2), we observe the discharging and charging time for 3s3p is increasing. The SoC of the individual configuration does not coincide each other, with the slope of 0.0133 at discharging of 80% and charging of 100%. Upon monitoring we observe that connecting more cells in series, has less contribution towards change in SoC, whereas in parallel connection, there is a difference in the state of charge depending on charge and discharge rates. Simulations has been carried out in T=20000, a complex current pattern is used in simulation to verify PF's performance. Based on given SOC, the discharging pattern is commonly changed in short time battery current (Fig.3). Thereby, changing the position of the cell effects the SOC of the battery packs, can be effectively monitored using Particle filter by setting number of particles, that is M as 1000. As lithium ions batteries have a great importance and widely used in Electrical vehicles because of their power efficiency, high charging rate, more lifetime, so proper monitoring of state of charge plays a vital role in Battery Management System [5].</p> <p>&nbsp;</p> Bhabya Sinha Arunima Adhikary Nandini P Venkatesh Chakravartula Samiappan Dhanalakshmi Rajamanickam Narayanamoorthi Copyright (c) 2021 Bhabya Sinha, Arunima Adhikary, Nandini P, Venkatesh Chakravartula, Samiappan Dhanalakshmi, Rajamanickam Narayanamoorthi 2021-09-16 2021-09-16 1 01 THE EFFECT OF SHEAR STRESS ON REDUCING THE FROUDES NUMBER ON THE CREST OF OGEE WEIR https://spast.org/techrep/article/view/2894 <p>The surface roughnesses on the downstream floor of the weir reduces the froude's number, reduces and stabilizes the hydraulic jump. The sher stress developed on the surface due to its roughness has reduced the jump height through which the erosion/scouring, this effect also reduces the construction cost of the stilling basin by reducing the length and thickness of the stilling basin. In this paper the downstream of the ogee weir is placed with a small length of construction aggregates which can be used an effective and economical way to reduce the impact of the jumps. The shear force generated across the surface of the longitudinal axis tilting flume withheld the&nbsp; velocity of the flow at the downstream thus reducing the scouring affect and&nbsp; roller length of the hydraulic jump which narrows the down the velocty of the flow and additionally, the shear stress grows sharply with the increasing approach Froude's number.&nbsp;</p> Mekapothula Sravani Copyright (c) 2021 Mekapothula Sravani 2021-10-21 2021-10-21 1 01 Wireless Power Transfer for Electric Vehicle https://spast.org/techrep/article/view/2198 <p>In this 21<sup>st</sup> century the vehicles which is seen as feasible mode of transport every day is Electric Vehicles - EVs, the future cars. It offers many benefits to individuals as well as business. &nbsp;Because of the technical growth EVs are now available to suit a range of budget [1-2]. Driving of EV improves the environment we live in because it doesn’t produce any carbon monoxide which causes the pollution of air. Since an electric car on the road saves carbon monoxide at an average of about 1.5 million grams. EVs become an enticing solution as it improves the health of the residents, quality of life and air. EVs- the future transport is limited by the distance it can travel. In order to overcome the range anxiety, it becomes necessary to propose a design that makes EVs more reliable and autonomous. The promising design that can transfer power while a vehicle in motion is dynamic wireless charging. Wireless power transfer (WPT) can rise the driving scope of EVs by charging in shopping centers, parking garages, etc. WPTs are extremely appealing for some modern applications in light of their advantages contrasted with the wired partner, like no unprotected wires, simplicity of charging, and bold transmission of force in contradicting ecological conditions [3]. WPT is accomplished through the reasonable inductive coupling between two curls called transmitter and beneficiary loop. Reception of WPTs to charge the onboard batteries of an electric vehicle (EV). In EV charging applications, transmitter loops are covered in the street and beneficiary curls are situated in the vehicle. EV charging circuit integrated with IoT to make the user aware of the charge available in the battery. To analyze and propose a converter that would improve the performance of EV.</p> <p>Square outline is a graph of a framework, wherein the chief parts or capacities are addressed by blocks associated by lines that show the connections of the blocks. They, are intensely utilized in the designing scene in equipment plan, electronic plan, programming plan, and interaction stream diagrams. The ordinary force lattice and to work with the consistent activity of the power conveyance framework even in brutal climate, diminishing the likelihood of disappointments. utilizing lattice network for conveying power from makers to consumers. This, circuit consolidates the elements of the rectifier and DC to DC converter, as opposed to utilizing the rectifier to change AC over to DC and afterward providing the necessary voltage with controller as in the momentary technique. This alteration can lessen the force utilization and the space of the circuit. It’s equipped for changing AC voltage over to DC voltage. It will go to the DC to AC channel. we need to utilize 2 channels, in light of the fact that we have 2 loops. The high-recurrence inverter (DC-AC) associates with a TX curl and a remuneration network that goes about as a receiving wire. The TX curl is liable for creating the ideal electric or potentially attractive fields that couple the energy to the accepting side through a remote medium. It is an electrical gadget which is created and intended to satisfy the need of high recurrence. It gives yield as high recurrence having range up to kHz. at last voltage will go to the essential loop. The proposed transmitter curl is delineated in figure 1.</p> <p><img src="https://spast.org/public/site/images/sivagamipdkv/mceclip0.png"></p> <p>&nbsp;</p> <p><strong>Fig.1.</strong> Transmitter curl in WPT for EV</p> <p><img src="https://spast.org/public/site/images/sivagamipdkv/mceclip1.png"></p> <p><strong>Fig.2.</strong> Reciever communication link in WPT for EV</p> <p>Essential loop sends the capacity to HF auxiliary side. at that point HF correction channel, A rectifier is an electrical gadget that converts rotating flow (AC), which occasionally switches course, to coordinate flow (DC), which streams just a single way. Correction may serve in jobs other than to create direct current for use as a wellspring of force. The lift converter is utilized to "venture up" an information voltage to some more elevated level, needed by a heap. This extraordinary ability is accomplished by putting away energy in an inductor and delivering it to the heap at a higher voltage. This short note features a portion of the more normal traps when utilizing support controllers. we need to utilize two transfers; one is charging cut off/on and another is engine/on. hand-off is utilized to when battery charge is filled it will be cut the interaction. PWM can be utilized to control the measure of force conveyed to a heap without causing the misfortunes that would result from direct influence conveyance by resistive means. High recurrence PWM influence control frameworks are effectively feasible with semiconductor switches. A voltage sensor is a sensor used to figure and screen the measure of voltage in an item. Voltage sensors can decide the AC voltage or DC voltage level. The contribution of this sensor is the voltage, though the yield is the switches, simple voltage signal, a current sign, or a perceptible sign. We need to utilize two sensor, curl voltage sensor and battery voltage sensor. The Battery Voltage Sensor gives clients more exact battery charging giving you tranquillity of mind that the charge regulator is working as adequately as it ought to. On specific applications with long. Current sensor used to quantify the heap flow. A flow sensor is a gadget that recognizes electric flow in a wire and produces a sign corresponding to that flow . battery is utilized to store the charges. Electric engines transform power into movement by misusing electromagnetic enlistment. In LCD module, we can see the yield like how much voltage in battery and loop. &nbsp;what's more, WIFI module used to share the area in vehicle. The figure 2 sketches the receiver communication link in WPT for EV. Thus WPT is the attractive solution for overcoming the limitation of EVs such as the distance that it can travel and the size of the battery.</p> SIVAGAMI PONNALAGARSAMY Copyright (c) 2021 SIVAGAMI PONNALAGARSAMY 2021-10-07 2021-10-07 1 01 Zinc oxide nanostructural materials for wearable thermoelectric device applications https://spast.org/techrep/article/view/2126 <p>Among the semiconductor materials, zinc oxide (ZnO) nanostructures have attracted considerable attention due to their attractive electronic properties for applications depending on the size and morphology. In the present work, we investigate fabrication the relevant thermoelectric parameters, e.g., electric conductivity, Seebeck coefficient, of two-dimensional ZnO nanoflakes.&nbsp;&nbsp; The ZnO nanoflakes were prepared by a two-step hydrothermal method at a constant temperature and were in-situ with cotton fabric. The resultant nanoflakes have an average size of 100 – 500 nm, observed by using field emission scanning electron microscopy (FE-SEM). The phase purity and homogeneity of the fabric were investigated by x-ray diffraction (XRD). Measured Seebeck coefficient and electrical resistivity of ZnO nanoflakes/cotton fabric were -77µV/K and 3.4x10<sup>-5</sup>Ωcm, respectively. Hence, its power factor was evaluated to be 1.7x10<sup>-2</sup> W/m-K<sup>2</sup>.</p> NANTHINI NEMISH Copyright (c) 2021 NANTHINI NEMISH 2021-10-08 2021-10-08 1 01 Investigation of LiVMO4F (M=B, Si) Tavorites as cathodes for lithium storage systems under sensitive mode operations https://spast.org/techrep/article/view/1012 <p>Li-ion battery technology has evolved a lot in terms of capacity, energy, and power density when compared to first-generation batteries. However, the cost and safety are of a big concern. Cathodes with expensive elements, large manufacturing, and production costs due to a complex synthesis process have to be considered since they are the prime member of a battery. Also, cathodes are yet under continuous research, to attain a higher energy density and an efficient material that can be replaced with commercial cathode materials for better output. Even though a lot of batteries have been explored beyond Li-ion batteries, there is no higher possibility for them to be commercialized for wide usage in the near future. Hence, the immediate achievement of better battery technology to cope up with the present innovations is to tune in the present Li-ion battery for efficient use.[1] Recently, Polyanionic cathodes have drawn greater attention towards Li-ion batteries owing to their stability during the Li-ion insertion/extraction. Tavorites are one among them with greater benefits for the electrochemical systems, especially in Rechargeable batteries.[2] Herein, LiVMO4F (M=B, Si) based Tavorite structures are investigated as cathodes for Li-ion batteries under sensitive mode operations, i.e., at a temperature of 55 °C and -10 °C.[3–5] Theoretically, the battery system at a lower temperature is expected to perform lesser than the system at room temperature because of the lack in kinetic energy owing to the near-freezing point at an atomic level. This has become true in the case of VSF (LiVSiO4F), while VBF (LiVBO4F) depicts the opposite by exhibiting a greater specific capacity at -10 °C than at ambient temperature. On the whole, VBF displayed better electrochemical properties based on its tightly packed covalent bond resulting in structural stability along with its multivalent behavior. This interesting property of VBF seems promising for its applications in rechargeable battery systems in low-temperature regions. This research might pave the way for neoteric Tavorite structured electrodes in future energy storage and conversion devices.</p> Kiran Preethi Kirubakaran Chenrayan Senthil Marimuthu Priyadarshini Kumaran Vediappan Copyright (c) 2021 Kiran Preethi Kirubakaran, Chenrayan Senthil, Marimuthu Priyadarshini, Kumaran Vediappan 2021-09-21 2021-09-21 1 01 Eco-friendly and Renewable Power Generation from Heat using Thermophotovoltaic Technology. https://spast.org/techrep/article/view/641 <p><span style="font-weight: 400;">Renewable energy sources are the need of the hour, considering climate change’s impact on our planet. Although many such sources are currently being researched, none of them are commercially stable enough to compete with the existing non-renewable energy sources, with the main reason being performance for the price</span><span style="font-weight: 400;">[1]</span><span style="font-weight: 400;">. We believe our topic is relevant and necessary because </span><span style="font-weight: 400;">it is essential to develop a reliable energy source to aid ongoing developments in renewable energy generation. </span><span style="font-weight: 400;">The challenge is to accommodate the ongoing research of this technology into real systems. Restricted infrastructure development is responsible for the lag in further developments of this technology for commercial applications. We aim to develop a practical system based on the current research progress in infrared-based thermophotovoltaic power generation and storage</span><span style="font-weight: 400;">[2]</span><span style="font-weight: 400;">. Similar systems already exist for harnessing solar energy, but we plan to overcome the inability of solar energy to produce electricity in the absence of sunlight by developing an infrared-based system. Another challenge being the unavailability of enough thermal radiation in the vicinity to support the system from different sources. The main objectives of this work are to identify the advantages and disadvantages of such a system, its feasibility, and efficiency for working in the real world through theoretical predictions, simulation, and, if possible, experimentation. Thermophotovoltaic technology is currently under extensive research; the discovery of carbon nanotubes to capture a broad spectrum of thermal radiation and narrow it down to emit a shorter range has enabled researchers to generate power from infrared radiations</span><span style="font-weight: 400;">[3-6]</span><span style="font-weight: 400;">. Our proposed hypothesis is that integrating infrared-powered electricity generation can work similarly to solar energy harnessing systems. Components of a general photovoltaic system are divided into three main parts, namely solar panels, power inverter (to convert DC to AC), and batteries for energy storage</span><span style="font-weight: 400;">[7]</span><span style="font-weight: 400;">. For the thermophotovoltaic (TPV) system to work efficiently (by using light as an intermediary to convert heat to electricity), at least three components are required: a heat source, an emitter, and a photovoltaic (PV) cell with a low bandgap</span><span style="font-weight: 400;">[2]</span><span style="font-weight: 400;">. We intend to use a similar flow of components where the solar panels shall be replaced by heat-powered cells, thus allowing electricity generation when enough sunlight is not available</span><span style="font-weight: 400;">[5]</span><span style="font-weight: 400;">. The bigger picture of this work could be developing a system capable of producing and storing energy during the summers. The stored energy is sufficient to run during winters. Also, combining it with solar panels could give double benefit, increasing the overall absorption spectrum for an efficient generation with minimum wastage of energy present in the surroundings. Although renewable energy sources require massive infrastructure and great initial capital for setting up, they prove to be far more economical and reliable as time passes. Our project should be looked at as an investment in the future, leading the way toward a greener and cleaner planet. This is an essential step, keeping the future of the planet in mind. The use of non-renewable energy resources has already caused multiple problems across the world, like extensive scale pollution, depletion of the resources, global warming, and depletion of the ozone layer. </span></p> <p><span style="font-weight: 400;"><img src="https://spast.org/public/site/images/hrishikeshgokhale/untitled-diagram.drawio-2.png" alt="Fig.1.Flowchart: System workflow." width="517" height="852"></span></p> <p><strong>Fig.1.</strong><span style="font-weight: 400;">Flowchart: System workflow</span><span style="font-weight: 400;">.</span></p> Hrishikesh Gokhale Lochan Chaudhari Copyright (c) 2021 Hrishikesh Gokhale, Lochan Chaudhari 2021-09-16 2021-09-16 1 01 Tuning the tribological properties of Ni/NiO thin films by Nd:YAG pulsed laser irradiation https://spast.org/techrep/article/view/3984 <p>Nickel (Ni) is one of the most common metal coatings used to synthesize composite <br>electrochemical coatings (CECs) as it is characterized by superior corrosion resistance, and <br>enhanced mechanical and tribological properties. Ni-based alloy coatings have been widely <br>used as wear materials [1]. The most employed Ni-based alloy coatings are NiFe, NiW, and <br>NiFeW. Ni, as the major element, provides ductility and enhances the corrosion resistance [2]. <br>These coatings are widely used in gas turbines and in oil and steel industries, where sliding <br>or erosion between one or more bodies is commonly encountered. Ni-based alloy coatings <br>may also be more suitable than Co-based alloy coatings due to their better antiwear properties <br>and lower costs. Recently, graphene has been used in the electrodeposition of Ni composite <br>coatings known as nickel-graphene (Ni–Gr) coatings for lubrication application. Such coatings <br>are superior in tribological properties as compared to other hard CECs that consist of <br>chromium, boron nitride, zirconium dioxide, PTFE, etc [3]. Similarly, NiO is a well-known <br>antiferromagnetic material, and a metal-deficient p-type semiconductor with a 3.6 eV band <br>gap. Nickel oxide (NiO) films have a wide range of applications due to their excellent chemical <br>stability. They have been used as catalysts, electrochromic display devices, fuel cells and gas <br>sensors. NiO thin films usually exhibit p-type conductivity due to holes generated by Ni <br>vacancies in the lattice and therefore NiO is an interesting candidate for materials research<br>[4]. Although structural and electrical properties of NiO films have been studied extensively, <br>mechanical and tribological properties have been recently trending primarily due its ease of <br>deposition. Therefore, understanding the correlations between the mechanical properties and<br>microstructure of NiO-based films has been of great interest. In particular, it has been widely <br>conceived that the wide variety of methods used for fabricating NiO thin films often resulted in <br>very different film microstructures or even stoichiometries.<br>The present work aims at investigating how the nanomechanical properties and the surface <br>wettability of the Ni/NiO thin films deposited on glass substrates by radio-frequency magnetron <br>sputtering change with the post-deposition laser irradiation. A semiconductor laser based on <br>Nd:YAG operating at its 4th harmonic wavelength, λ = 266nm with varying laser fluence and <br>spot size of about 5 µm is irradiated on the Ni/NiO film. The localized heating allows for <br>smoothening of the NiO film along with contributions to the changes in the stoichiometry of <br>NiO (reduction of excess oxygen) and creation of Ni interstitials. In particular, the effects of <br>tuning laser fluence and the subsequent evolution of films microstructure and the associated <br>nanomechanical properties of the Ni/NiO thin films revealed by the mechanical tests, wear <br>and coefficient of friction variations for tribological tests are discussed. The hardness (H) and <br>the elastic modulus (E) of NiO thin films are measured by nanoindentation and their <br>dependence on the laser fluence is studied. Raman analysis along with XRD analysis for structural changes due to laser irradiation and EDX were carried out to validate the dependence of laser fluence on the hardness of Ni/NiO thin films due to interstitials/ reduced <br>oxygen</p> Srikanth Itapu BHANU SRI PILLA Vamsi Borra Frank Li Copyright (c) 2021 Srikanth Itapu , BHANU SRI PILLA, Vamsi Borra, Frank Li 2021-12-30 2021-12-30 1 01 Ms Sheik Haseena https://spast.org/techrep/article/view/2144 <p>Organic solar cells (OSCs) can be a theoretically promising technology for providing clean and renewable energy. The significant advantages of OSCs compared to their counterparts are low-cost, lightweight, flexibility.[1] However, efficiency limitations, as well as long-term reliability, are major concerns. The design and development of new non-fullerene acceptors (NFAs) (used as electron acceptors in organic solar cells) is currently a major focus of the research. Several NFAs, such as fused ring aromatic cores with strong electron acceptors and rylene diimide-based materials, have shown promising power conversion efficiencies (PCEs).[2] Recently developed molecules ITIC and Y6-based acceptors have shown PCE of more than 18%.[3,4] However, key information related to structure-property relationships, donor-acceptor energy levels matching, and understanding the energy losses are important to improve the efficiencies of devices. In this context, computational studies provide more insights into the molecular level understanding on energy level matching and molecular packing between donor and acceptor materials.</p> <p>In this investigation, we computationally study whether the recently synthesized Cyclo[18]carbon (C<sub>18</sub>) molecule can be used as the electron acceptor in organic solar cells. Strong π-electron delocalization and high electron affinity make C<sub>18</sub> as the electron acceptor.[5] Thus, density functional theory-based methods are used to characterize the electronic properties, aromaticity, and the nature of interactions between C<sub>18</sub> molecules. The important criteria which control charge mobility are reorganization energies and electronic coupling between molecules. We have calculated the reorganization energies using state-of-the-art methods. The nature of interaction between C<sub>18 </sub>molecules is analyzed using symmetry-adapted perturbation theory (SAPT). The results obtained from this analysis are useful to understand the packing between molecules. The calculated reorganization energies and electronic couplings have shown good charge transport properties.</p> <p><img src="https://spast.org/public/site/images/maheshr06/fig1.png" alt="" width="339" height="215"></p> <p><strong>Fig.1.</strong> Optimized geometry of polyyne and cumulene structure along with bond angle and distance using CAM-B3LYP/6-311++G (2d,p) method.</p> <p>The optimized geometries of monomers are shown in fig. 1, along with the bond length data obtained from three different DFT methods. For this study, selecting a suitable DFT method is very important to identify the correct bond length and electronic structure of these molecules. In this study, we have demonstrated the importance of long-range corrected DFT methods for the proper description of highly delocalized bonds.</p> <p>The aromatic behavior of molecules depends on the nature of bonding (σ and π bonds) between carbon and carbon (C-C) atoms. From our DFT simulations we found the double aromatic nature of C18 rings. The delocalization of two scaffolds of π-electrons oriented towards in-plane (π<sub>in</sub>) and out-of-plane (π<sub>out</sub>). Thus, there is a double aromaticity behavior in the circular form of C<sub>18</sub> molecules. The bond order differences in polyyne and cumulene rings reflect through aromatic character.</p> <p><img src="https://spast.org/public/site/images/maheshr06/fig2a.png" alt="" width="412" height="147"></p> <p><strong>Fig.2.</strong> Graphical representation of energy decomposition analysis of two C18 rings at a. eclipsed position change in vertical distance from 2.5Å to 4.5Å. All calculations are carried out using SAPT/aug-cc-pvdz level of theory.</p> <p>Based on the results obtained from both analyses, we consider only cumulene ring structure for further analysis. The energy decomposition analysis on dimers of C<sub>18</sub> is carried out to gain more insights into the nature of interactions between the ring structures and also packing of these molecules in the thin-films. One can see from fig. 2 that the major contribution to the stabilization complex came from the dispersion energy. The large repulsive exchange energy compensates attractive terms. However, it is interesting to note that the large exchange-repulsion indicates the considerable overlap of electron densities. Such a large overlap of electron density might lead to large electronic coupling between rings. We have calculated the electronic coupling values between the rings, and we found (LUMO-LUMO) electronic couplings values in the rages of 400 meV. As discussed before, large electronic couplings and low internal reorganization energies are the key parameters for better charge mobilities. Results obtained from our calculations indicate that the C<sub>18</sub> may exhibit better charge mobilities as it shows large electronic coupling with low reorganization energies.</p> <p><img src="https://spast.org/public/site/images/maheshr06/fig3.png" alt="" width="394" height="157"></p> <p><strong>Fig.3.</strong> pictorial representation of hole and electron wavefunctions in pentacene-C18 clusters in the lowest excited states.</p> <p>Further, we have also studied donor-acceptor complexes based on pentacene-C<sub>18</sub> clusters as model systems. Time-dependent DFT analysis is carried out to characterize the excited state properties of these clusters. Fig. 3 shows the hole and electron wavefunctions of pentance-C<sub>18</sub> clusters in the lowest excited state. The excited state analysis on these clusters reveals that the C<sub>18</sub> molecule can be used as acceptor molecules as the lowest excited state has charge transfer in nature (hole localized on pentacene and electron localized on C<sub>18</sub>). We have studied how molecular packing between donor and acceptor molecules impact the hole and electron delocalization in the excited states. These results give insights into the charge dissociation property of the system of interest. All these results will be useful to provide designing rules for the experimentalist. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> Mahesh Kumar Ravva Sheik Haseena Prakash Muthuramalingam Maiyelvaganan K. R. Copyright (c) 2021 Mahesh Kumar Ravva, Haseena, Prakash, Maiyelvaganan 2021-10-08 2021-10-08 1 01 Supercapacitive Behaviour of Chemically Prepared Manganese Dioxide/Aluminum Counter Cation-Based Monophosphate Tungsten Bronze Composites https://spast.org/techrep/article/view/1524 <p>A marked increase in energy consumption has been seen in the recent years due to large population growth. So there have been a global cry for efficient energy storage and conversion devices that can meet up our day to day demand towards energy consumption. Hence, one of the colossal challenges in the energy sector is the storage and safe distribution of electrical energy. In this regard, a low-cost, environmentally benign electrochemical energy storage device with enormous power density, supercapacitors, can play a very vital role in the path of checking this burning issue [1]. Supercapacitors usually store energy via electrostatic double layer formation with higher power density compared with batteries but they demonstrate a lower energy density [2]. With the introduction of pseudocapacitance, energy density can be improved. For that very purpose <em>transition metal oxides</em> (like RuO<sub>2</sub>, MnO<sub>2</sub> etc.) can play a very significant role [3]. Manganese dioxide (MnO<sub>2</sub>) has been deemed as one of the most promising materials for its unique properties like high theoretical specific capacitance (1370 Fg<sup>-1</sup>), low-cost, environmental benignity, non-toxic and natural abundance [4]. Polyoxometalates (POMs), nanosized transition metal oxide clusters, have attracted much attention over recent years as an electrode material for their high stability, non-toxicity, rapid reversible multi-electronic redox reactions, and catalytic activity. POMs provide its stable inorganic molecular framework for dispersion of nano-materials in a composite [5]. In this study, the capacitive behavior of composites of MnO<sub>2 </sub>and POM-Al (<em>MP-X</em>) with different compositions have been investigated. Manganese dioxide (MnO<sub>2</sub>) has been synthesized successfully from the reduction of potassium permanganate (KMnO<sub>4</sub>) by sodium thiosulphate (Na<sub>2</sub>S<sub>2</sub>O<sub>3</sub>) in aqueous medium [6]. POM-Al has been synthesized separately from tungstic acid (H<sub>2</sub>WO<sub>4</sub>), aluminum nitrate nonahydrate (Al(NO<sub>3</sub>)<sub>3</sub>.9H<sub>2</sub>O and ammonium dihydrogen phosphate (NH<sub>4</sub>H<sub>2</sub>PO<sub>4</sub>) [6], whereas <em>MP-X</em> composite has been prepared through solution dispersion method by mixing POM-Al and MnO<sub>2</sub> particles (X = % POM-Al) in appropriate proportions. The as-synthesized materials has been characterized by Fourier-transform infrared and UV-visible spectroscopy. Pristine POM-Al and MnO<sub>2 </sub>fabricated on graphite electrode surface have specific capacitances of 2.15 F g<sup>-1 </sup>and 327 F g<sup>-1</sup> respectively in 0.5 M Na<sub>2</sub>SO<sub>4</sub> aqueous solution (Fig.1a). With the addition of only 5% of MnO<sub>2 </sub>in the composite, the specific capacitance of POM-Al has drastically increased to 15 F g<sup>-1</sup>. Further increase of specific capacitance due to the addition of MnO<sub>2 </sub>in the <em>MP-X</em> composites has been observed (Fig.1a)<sub>. </sub>The prepared <em>MP-X </em>composite shows high specific capacitance with longer life time as well as higher power and energy density. Further improvements of this existing system can lead to a device that can meet up the global demand for an efficient energy storage device.<img src="https://spast.org/public/site/images/akibhasan04/firgure-abstract.png" alt=""></p> <p><strong>Fig.1. </strong>(a) Galvanostatic charging-discharging curves of a) POM-Al, b) MP - 95, c) MP - 50, d) MP - 15, e) MP - 3.5, g) MnO<sub>2</sub> modified electrode at 0.1 A g<sup>-1</sup> current density, (b) Cyclic voltammograms of a) MP - 95, b) MP - 50, c) MP - 15, d) MP - 3.5, e) MnO<sub>2</sub>(MP - 0) modified electrode in 0.5 M Na<sub>2</sub>SO<sub>4</sub> aqueous solution at the potential scan rate of 0.01 Vs<sup>-1</sup>, and (c) Schematic diagram of the present work.</p> Md. Akib Hasan Dr. Md. Mominul Islam Copyright (c) 2021 Md. Akib Hasan, Dr. Md. Mominul Islam 2021-10-07 2021-10-07 1 01 A Mini Review on Electrospun PVDF- Doped Metal Oxide Nanoparticles for Sensor Applications https://spast.org/techrep/article/view/1974 <p>Due to the over consumption of natural sources like petroleum and coal, researchers have started paying attention to balance the energy crisis in alternative way such as fabricating energy storage and harvesting devices. Identifying polymers having appreciable dielectric and piezoelectric properties for fabricating energy storage devices is an area of interest to our research group. Among the many fluoropolymers, polyvinylidene fluoride (PVDF) is well-known since 1960s and is preferred for its exhibition of inordinate mechanical properties and complicated polymorphism. Usually, PVDF exhibits four crystalline forms namely <em>α</em>, <em>β</em>, <em>γ</em> and <em>δ</em>. Most common polymorph was <em>α</em>-crystalline phase and upon crystallization from melt, <em>β</em>-phase could be formed. <em>β</em>-phase is the most important polymorph with excellent piezoelectric and pyroelectric properties [1]. The effect of nanoparticles (NPs) in improving the electrical characteristics of PVDF has generated numerous publications since the last decade and a review paper in this topic will be of interest to many researchers working in this field. Basically, NPs can be classified as atom clusters with at least 1-D in the nanoscale size range (1~100 nm). NPs are used in diverse applications owing to their unique physical and electrical (optical, magnetic &amp; catalytic) properties. In recent times, many research groups have focussed on synthesizing Fe, Co and Ni oxides based magnetic NPs for data storage and sensor applications due to their higher thermal and mechanical stability which is essential to survive in severe working conditions [2]..More importantly, transition metal cations can exist in several different valence states [3], and their crystallite size increased with increasing addition of metal doping [4].&nbsp; Incorporation of metal oxides and doped metal oxides with PVDF plays a vital role in the improvement in piezoelectric sensor sensitivity. This mini-review presents recent advancement in metal oxides doping with PVDF and its effectiveness towards the sensors application. This mini-review focuses to provide the key note for synthesising a novel and economically cheap material for energy storage and harvesting process. From the overall literature, it was observed that most of the published reviews and research articles explained only on synthesis of metal oxides and doped metal oxide in different synthetic methods. In our review, we aim to bring about the correlation of metal oxide and doped metal oxide with PVDF and the resultant changes in electrical properties. From the literature review, it was clear that doping a metal with other metal oxides enhancing the crystallite size, and it will enhance the sensitivity of material for sensor applications. The core objectives of the review are (i). How the metal oxides and doped metal oxides with PVDF will be prepared by simple chemical synthesis? and (2). How it will be useful to fabricate the energy storage and energy harvesting devices which is going to fulfil the future energy imbalance? Acknowledgement: This work was supported by CSIR, Government of India under CSIR-EMR-II scheme (03(1450)18/EMR-II dt.05-06-2018). A.A.P also thank VIT for providing ‘VIT SEED GRANT’ for carrying out this research work.</p> HEMA MALINI V Indumathy B GUNASEKHAR R Anand Prabu Arun Copyright (c) 2021 HEMA MALINI V, Indumathy B, GUNASEKHAR R, Anand Prabu Arun 2021-10-09 2021-10-09 1 01 Cost Optimization and Emission control of a Grid connected Hybrid PV-Wind system for a Health Care Centre in India https://spast.org/techrep/article/view/1724 <p>Due attention is needed for energy demand in health care centers as energy requirement for average Energy Use Intensity (EUI) is huge. It is to be noted that EUI is the energy per square foot per year. The technology advancement result in sophisticated and inevitable equipment, increases the energy consumption of the health care centers. The maintenance of these equipment and increase in the patient to doctor ratio are also one of the main reason which affects the energy consumption. India is found to be the fourth largest greenhouse gasses emitter. As a result, India is much affected by the change in climatic conditions. Therefore the obligatory situation is arised in India to reduce the global warming which can be possible with the penetration of renewable energy based electricity generation. Our major objective is to produce the electrical energy with the optimized PV- wind system and to avoid the global warming with the optimized energy generation technology.</p> <p>The novelty in the work is to generate the electricity with Hybrid pv-wind&nbsp;system for a health care centre in India, and to payback the excess energy produced to the electricity board through grid system. &nbsp;&nbsp;</p> <p>A health care center which uses 160kWh/day of electrical load and deferrable load of 10kWh/d is taken for analysis. 200 kW of PV and 100 kW of wind generation capacity&nbsp;are proposed for generating power. The monthly average wind speed profile and solar profile is downloaded from NASA Prediction of Worldwide Energy Resource database. 300kW converter is used, with the mean output of 38.8W capacity is used in the proposed system for power conversion.An idealized battery storage system of 48V is introduced with the capacity of 139kWh and round trip efficiency of 64%.</p> <p>Homerpro 3.11.2 is used to obtain and analyse the optimization result. The analysis gives best solution for cost summary, economic comparison in using various resources. This microgrid requires 1938 kWh/day and has a peak of 305 kW. In the proposed system, the energy demand, energy selling and cost analysis is done. The energy demand of the health care system is estimated and the remaining energy produced is sold back to the grid. Grid power is connected to the system with simple rates of grid power rate and sell back rates.</p> <p>From the Homer Analysis, the Net Present Value, total Annualized Cost, simple payback, Return on Investment (ROI), the Internal Rate of Return (IRR) and annual savings are estimated for the proposed system. It is estimated that our investment has a payback of 1.33 years and an IRR of 75.3%. The annual energy purchased from the grid is 6,639 kWh and the annual energy sold to the grid is 643,549 kWh.</p> <p>Along with the cost analysis, &nbsp;the emission of gases like carbon dioxide, carbon monoxide, unburned hydrocarbons, particulate matter, sulfur dioxide and nitrogen oxides are also calculated for the proposed system. The analysed result gives null result for the emission of green house gases and the proposed system becomes environmental friendly system in reducing the global warming. Also cost analysis of the proposed system proves the annual savings in regards with the energy consumption.</p> Abitha Memala W Bhuvaneswari C Susitra D Copyright (c) 2021 Abitha Memala W, Bhuvaneswari C, Susitra D 2021-10-08 2021-10-08 1 01 Designing a solar PV module for powering an electrolyzer https://spast.org/techrep/article/view/934 <p>The rapid depletion of fossil fuels, rise in the cost and demand for energy, greenhouse gas emissions, and global warming have collectively led to the requirement of generating clean energy through renewable energy sources. Among all renewable resources, solar energy proves to be of the highest potential owing to its abundant and inexhaustible nature. Solar power capacity in India has increased from 6.7 GW to 40 GW as of March 2021. The use of solar energy can partially address the issue. The reduction of greenhouse emissions is a major concern and can be addressed only by finding an alternative to fossil fuels. One possible alternative is hydrogen which turns out to be a green and clean energy carrier if produced via electrolysis. Further, the electrolyzer should be integrated with a solar photovoltaic system to make it fully sustainable [1].</p> <p>Solar energy is ubiquitous, making it a viable contender for coupling with electrolyzers. Solar PV systems can be combined with a dual-functional electrolyzer, producing hydrogen by electrolysis and removing the waste heat by active cooling. When compared to a stand-alone electrolyzer at an ambient temperature, it is seen that this system has an energy efficiency of 56-59%, and integrating the electrolyzer to the PV module results in the increase of hydrogen production by almost 2.5 folds. Hence, to enhance the application of solar PV technologies, coupling with electrolyzers proves to be a significant approach. Solar PV arrays can be directly coupled with PEM electrolyzers to improve the system efficiency as shown in fig. 1A. Power transfer efficiency close to 99% can be achieved by connecting electrolyzer cells in series or parallel and by matching the PV systems’ curve connecting MPPs and different irradiation levels to the electrolyzer polarization curve [3]. A PV-Electrolysis system with an InGaP/GaAs/GaInNAsSb triple-junctional solar cell with two PEM electrolyzers in series, achieving a 48-h solar-to-hydrogen (STH) efficiency of 30%, is depicted in fig. 1B [4].&nbsp;</p> <p>A challenge in coupling a solar PV system with an electrolyzer is that there can be a mismatch between the Maximum Power Point of the solar cell and I-V characteristics of the electrolyzer due to variation in solar irradiation during the day, to resolve which a DC/DC regulator can be added. The PV-Electrolyzer Systems’ I-V Characteristics have to be accurately predicted for constructing and optimizing the system. Moreover, the solar resource is intermittent, available only during the day, and subject to fluctuations. Hence there is a requirement for a storage system, which, however, adds to the life cycle cost of the system. Overcoming these challenges can lead to the successful integration of solar PV systems with electrolyzers, thereby enhancing the production of Green Hydrogen, a recent ally to a carbon-neutral future.</p> Ujwal Shreenag Meda Aditi Pandey Yashesh Vijay Rajyaguru Manjunatha C Copyright (c) 2021 Ujwal Shreenag Meda, Aditi Pandey, Yashesh Vijay Rajyaguru, Manjunatha C 2021-09-18 2021-09-18 1 01 Graphite counter electrode for Cost effective Dye Sensitized Solar Cells (DSSCs) https://spast.org/techrep/article/view/1202 <p>Dye Sensitized Solar Cells (DSSCs - Grätzel cell) are the third generation thin film solar cells which are emerging photovoltaic techniques to produce electricity. &nbsp;This bionic model of the photo electrochemical cell is composed of dye coated nanoporous photoanode which is sandwiched together with a counter electrode to catalyze the (reduce) electrolyte with electrons from the external circuit [1,2]. At first (in 60s) DSSCs were demonstrated with the metal oxide electrodes like ZnO, TiO<sub>2</sub>, and SnO<sub>2 </sub>etc. which are sensitized with Chlorophyll and derivatives of the chlorophyll and Rose Bengal [3,4]. Platinum (Pt CE) was used as the counter electrode since it has very good catalytic property. Grätzel et al demonstrated the TiO<sub>2</sub> sensitized with Ru complex dyes, LiI<sub>2</sub> electrolyte and Pt CE, they got extraordinary performance.&nbsp; It is indispensable to find low cost and earth abundant materials for the CEs which are having high electrical conductivity, electro chemical catalytic properties to reduce the electrolyte and also having chemical stability. By the way carbon based electrodes are the inexpensive and simple alternative materials to the Pt CE. Since these carbon based counter electrodes show the excellent electrochemical catalytic activities [5]. We have fabricated DSSCs with graphite coated on aluminium as the CE at low cost instead of Pt based CEs. Lithium per chlorate (LiClO<sub>4</sub>) which is inexpensive and forms highly conductive solutions with carbon based electrodes and perform very well [6]. Hydrothermally synthesized TiO<sub>2</sub> nanoparticles were coated onto FTO glass plates and sensitized with Eosin Y (EY) dye. The Graphite counter electrode (G) was fabricated by G coating onto the Al and then the cells were assembled by sandwiching the TiO<sub>2</sub> photo anode (soaked in EY) and the counter electrode. The assembled FTO/TiO<sub>2</sub>+EY/Electrolyte/CE solar cells were subjected to I-V characteristics under a light source of 100mW/cm<sup>2</sup>. I-V measurement was carried out for Pt CE, and for the Gl CE based DSSCs. Cell structure and the working mechanism of the DSSC with Pt CE are shown in the Fig.1.A, and I-V characteristics for the assembled DSSCs which is based on Pt CE is shown in the Fig.1.B. For the G/Al CE based DSSC structure and I-V characteristics are given in Fig.1.C. and Fig.1.D., respectively. The photovoltaic performances of the fabricated cells were tabled in Table 1. From the result Cell with Pt CE shows high open circuit voltage (V<sub>OC</sub>) 0.717V and fill factor (FF) 0.51, where the G/Al CE based cell gives short circuit current (I<sub>SC</sub>) 1.4 mA and photo conversion efficiency (η) 0.56%. Finally cell which is fabricated with G counter electrode shows better performance than Pt CE based cell. Since carbon has good electrochemical property. Further we investigate by using graphene or activated charcoal instead of graphite due to the property of high surface area to get good conversion efficiency.</p> Karuppasamy Balasubramanian Gayathri Venkatachari Copyright (c) 2021 Karuppasamy Balasubramanian, Gayathri Venkatachari 2021-09-24 2021-09-24 1 01 A Mini Review on Electrospun PVDF-Metal Nanoparticle Composites for Electronic Applications https://spast.org/techrep/article/view/2067 <p>Due to the increase in world population, the demand for energy is also increasing, Hence, researchers are now interested to explore alternative energy resources to that of conventional energy resources that can be found in ambient environment like mechanical vibration, fluid flow, radio and EM waves, heat, etc. Among this, mechanical energetic form is considered to be omnipresent form of energy which can be easily converted to useful power. Piezoelectric mechanism is the most efficient technology for converting mechanical energy to useful power output and ease of manufacturing [1]. During 19<sup>th</sup> century, Curie et al and Lipmann proposed the concept of piezoelectricity [2]. Unlike any other mechanism, piezoelectricity does not require any additional voltage, contact with any other material and magnetic force field. Piezoelectricity is simply internal polarization of the material upon the application of stress, and this polarization creates electric field that can convert mechanical stress applied on the material to electrical energy [3]. Piezoelectricity can be seen in dielectric crystalline/semi-crystalline materials that possess dipole moment [2]. Piezoelectric materials ranging from naturally occurring crystals to synthetic materials such as Quartz, Rochelle salt, ceramics, polymers such as Nylons, PVDF, PVDF-TrFE&nbsp; copolymers and metal/carbon-based nanoparticles [2,4]. Compared to other piezoelectric materials, polymers are generating lots of interest because of their low cost, flexibility and ease of processing. Currently fluoropolymers, especially PVDF is one of the most promising commercially available piezo-material used in diverse applications such as wearable sensors, nanogenerators, actuators and some micro-devices because of its excellent thermal and mechanical property, high sensitivity, good chemical resistance and biocompatibility [2,5]. PVDF exist in at least four crystalline phases (<em>α, β, δ</em> and <em>γ</em>). Among these, <em>β</em>-phase attributes piezoelectric behaviour to PVDF since it exhibits all-trans arrangement with non-zero net dipole moment. Hence, the increase in <em>β</em>-phase leads to a better piezoelectric property. Preferable <em>β</em>-polymorph can be obtained by various processes (annealing, mechanical poling, rolling and electrospinning) [5]. A typical one-step process that is widely utilized for preparing highly oriented nanofibers with excellent crystallinity is electrospinning method [6]. Additionally, mixing of nanoparticle on to the polymer matrix also shows efficient improvement in electrical properties. In this mini-review, we have covered the crystallinity, piezoelectric response and electrical applications of electrospun PVDF nanofiber with the addition of various metals, metal-oxide, core-shell and some hybrid nanoparticles. Acknowledgement: One of the author (A.A.P) wish to thank MHRD-SPARC, India (No. 2018-2019/P399) for the financial support. A.A.P also thank VIT for providing ‘VIT SEED GRANT’ for carrying out this research work.</p> Reshma Indumathy B GUNASEKHAR R Anand Prabu Arun Copyright (c) 2021 Reshma, Indumathy B, GUNASEKHAR R, Anand Prabu Arun 2021-10-08 2021-10-08 1 01 Transport Properties of Novel LaCoTiIn Equiatomic Quaternary Heusler Alloy for Thermoelectric Energy Conversion https://spast.org/techrep/article/view/675 <p>The increasing global demand for green energy has prompted us to develop new methods for energy conversion to reduce the combustion of fossil fuels. Massive amounts of waste heat are generated in automobiles, nuclear reactors, space vehicles, and heavy machinery, etc., which emit approximately 65% of waste heat into the environment. Thermoelectric materials are widely regarded as one of the most effective renewable energy resources for waste heat recovery. Searching for new thermoelectric materials with effective transport properties that concentrate on the criterion of low thermal conductivity and high Seebeck coefficient. The thermoelectric material efficiency can be estimated using the figure of merit , where ‘ ’ is the thermal conductivity, ‘ ’ is the absolute temperature, ‘ ’ is the electrical conductivity, and ‘ ’ is the Seebeck coefficient. Many thermoelectric materials such as skutterudites, Zintl phases, clathrates, Cu<sub>2</sub>Se, etc., have been discovered. Heusler alloys are considered promising material with various properties, including thermoelectric effect, half-metallic ferromagnetism, spin-gapless semiconductivity, and shape memory effect [1]. Due to the small thermal conductivity, a remarkable Seebeck coefficient, tunable band structure, and half-metallic band gap around the Fermi level, extensive research on Heusler alloys have been conducted in recent years. Currently, the focus of research is on increasing the efficiency of thermoelectric materials by applying novel techniques such as alloying, doping, manufacturing phonon glass-like structures, and nanostructuring. A high density of states is experienced by an f electron contained materials that has bands close to the Fermi level, which leads to enhanced thermoelectric coefficients, as established experimentally [2]. In light of this fact, we should investigate materials that include f electrons based materials, such as the La based quaternary Heusler alloys. Recently, Sing et al. (2019) determined the &nbsp;values of LaCoCrX (X = Al, Ga) Heusler alloys, estimating that LaCoCrAl has a &nbsp;value of 0.94 at 600 K and LaCoCrGa has a &nbsp;value of 0.42 at 500 K, respectively. In this study, we determined the thermoelectric characteristics of novel LaCoTiIn quaternary Heusler alloy using first-principles calculations [3]. The computed physical properties are obtained using the Full Potential and Linearized Augmented Plane Wave (FP-LAPW) approach, which is implemented in the WIEN2k code and is based on the Generalized Gradient Approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) functional [4]. Thermoelectric transport coefficients were computed as embedded in the BoltzTraP simulation package in the semi-classic Boltzmann theory.&nbsp;The transport coefficients such as , , , and &nbsp;were determined for up spin and down spin channels and figures of merit ( ) given in Fig. 1, and the obtained results were listed in Table 1. The maximum figure of merit obtained in the majority spin state is around 0.94 at 850 K and is also maintained to a significant extent at all temperatures. As a result of those mentioned above, the LaCoTiIn quaternary Heusler alloy is ideal for high-efficiency thermoelectric applications.</p> V. Aravindan Copyright (c) 2021 V. Aravindan 2021-09-16 2021-09-16 1 01 Affordable and Sustainable Energy Generation Based on Fuel Cell to Enhance Voltage and Current Profile of Conventional Grid https://spast.org/techrep/article/view/2836 <p>This paper proposed the affordable and clean form of energy generation system tied to<br>existing power grid to improve voltage and current profile during three phase symmetrical<br>fault condition and thereby increasing the power quality at the grid. Harnessing power from<br>sustainable non-conventional energy sources (NCES) is popular in current scenario, as less<br>amount of carbon foot prints are encountered by these sources and are freely available in<br>enormous quantity. Sustainable energy like wind energy system, solar photovoltaic<br>generation system, geothermal energy generation, fuel cell and energy derived from ocean<br>in different form is the most common and clean form of energy generation system. As the<br>electricity generation based on conventional fossil fuels is associated with environment<br>pollution and the conventional sources are not sufficient to produce required power to meet<br>the future electricity demand. It is essential to take alternative sources which are<br>environment friendly, affordable and sustainable in characteristics. Although the sustainable<br>NCES are intermittent in nature and their integration to grid create instability in the system<br>parameters. Utilizing suitable technologies these systems are connected to the grid for<br>improving stability in the system parameters. Electricity generation based on fuel cell is<br>clean, and when connected to grid improves the voltage and current profile of the system.<br>This paper presented model design of 11KV fuel cell plant connected to the grid and<br>simulated in MATLAB environment [1-3]. The results obtained after simulation verified the<br>validity of the model and proved the applicability of the proposed system.<br>Grid connected 11 KV fuel cell plant is analyzed through simulation results obtained for a<br>three phase symmetrical line to ground (LG) fault existing for time t = 0.1 second to t = 0.3<br>second. The waveform of voltage and current generated from 11 KV fuel cell plant is shown<br>in Fig. 1 A. In Fig. 1 B waveforms of voltage and current during LG fault is shown when fuel<br>cell plant is connected to the grid. Simulation results obtained are critically observed and<br>analyzed for the grid system for the case of without fuel cell plant and when fuel cell plant is<br>connected to the grid. The voltage value is considerably increased and considerable<br>reduction in the current value is is recorded in for LG fault condition with fuel cell plant<br>connected to the three phase grid. Comparison of voltage and current value during normal<br>and fault condition with grid tied fuel cell plant and without of fuel cell plant is presented in<br>table 1. The outcome of results obtained shows the enhancement in voltage and current<br>profile. Special attention is given to incorporation and project execution at wide range of<br>sustainable energy sources [4] to the conventional grid. The proposed scheme will prove to<br>be a powerful idea for enterprises, power areas and innovative work reason with broadened plan of cutting edge control procedures and to make people aware of sustainable<br>development technologies.&nbsp;</p> Satyanarayan Joshi Gaurav Bharadwaj Ravindra Singh Chauhan Virendra Sharma Jeetendra Deegwal Copyright (c) 2021 Satyanarayan Joshi, Gaurav Bharadwaj, Ravindra Singh Chauhan, Virendra Sharma, Jeetendra Deegwal 2021-10-21 2021-10-21 1 01 High performance supercapacitor based on Activated carbon-supported vanadomanganates https://spast.org/techrep/article/view/849 <p>The increasing demand for renewable and sustainable energy in modern electronic industries has stimulated intensive research efforts to develop high-performance and environmentally friendly energy storage devices [1-3]. Supercapacitors (SCs) or ultracapacitors, also known as electrochemical capacitors, are emerging energy storage devices because of their high power density, excellent charge-discharge characteristics, high cycling life, and above all, the safest operation [4-6]. The pseudocapacitors electrode materials based on metal oxides/hydroxides with variable valence exhibit a higher specific capacitance than those based on high surface areas carbonaceous materials and conducting polymers as they can provide various oxidation states for efficient redox charge transfer. Therefore, significant efforts have been dedicated to searching for inexpensive transition metal oxides with good capacitive behaviors. In this regard, polyoxometalates serve as a multi-metal oxide water-soluble cluster of variable oxidation states and demonstrate as promising electrode materials for energy storage technology.&nbsp; Here, we introduce two new electrode materials to prepare supercapacitors and show a detailed comparative study of those materials using a two-electrode configuration.</p> <p>K<sub>7</sub>Mn<sup>IV</sup>V<sub>11</sub>O<sub>33</sub>.10 H<sub>2</sub>O (<strong>MnV<sub>11</sub></strong>) and K<sub>7</sub>Mn<sup>IV</sup>V<sub>13</sub>O<sub>38</sub>.18 H<sub>2</sub>O (<strong>MnV<sub>13</sub></strong>) were supported on the high surface area activated carbon (<strong>AC</strong>), which are used for the preparation of electrode materials, denoted as <strong>AC-MnV<sub>11</sub></strong> and <strong>AC-MnV<sub>13</sub></strong> for compounds MnV<sub>11</sub>, and MnV<sub>13</sub> respectively. To confirm the interaction between the pseudocapacitors materials (MnV<sub>11</sub> and MnV<sub>13</sub>) and high surface area activated carbon, the composites were characterized using various analytical techniques, mainly Infrared spectroscopy (FTIR), thermal stability analysis using TGA, crystallinity by powder X-ray diffraction, surface morphologies using FE-SEM, EDX, and surface activity by N<sub>2</sub> adsorption/desorption studies. Electrodes are prepared by depositing these composites upon carbon cloth, and their electrochemical properties concerning the supercapacitance behavior have been extensively studied. The electrochemical performance of all composite materials has been tested in an aqueous 0.1 M H<sub>2</sub>SO<sub>4</sub> electrolytic solution. <strong>AC-</strong><strong> MnV<sub>11</sub> </strong>electrode displays the highest specific capacitance of 479.73 Fg<sup>‑1</sup> at a current density of 0.4 Ag<sup>-1</sup>, along with incredible specific energy and power of 95.95 Whkg<sup>‑1</sup> and 960 Wkg<sup>‑1</sup>, respectively. Likewise, <strong>AC-MnV<sub>13</sub></strong> exhibits a specific capacitance of 357.33 Fg<sup>-1</sup> at the same current density of 0.4 Ag<sup>-1 </sup>with a high specific energy of 71.46 Whkg<sup>‑1</sup>. The <strong>AC-MnV<sub>11</sub></strong> electrode, therefore, shows more conducting and lower resistivity based on the Nyquist plot. Importantly, <strong>AC- MnV<sub>11</sub></strong> was observed to light up red and yellow colour LED bulbs for 80 and 60 seconds, respectively, suggesting a remarkable specific power of that material. Similarly, the <strong>AC-</strong><strong> MnV<sub>13</sub></strong> electrode could also light up the red and blue LED bulbs. Moreover, the<strong> AC-</strong><strong>MnV<sub>11</sub> and AC-MnV<sub>13</sub></strong> were also observed to retain 95.9 and 83.3% of the electrode stability after 10,000 charge-discharge cycles.&nbsp;</p> ANJANA ANANDAN VANNATHAN Copyright (c) 2021 ANJANA ANANDAN VANNATHAN 2021-09-18 2021-09-18 1 01 Life Cycle Assessment and Environmental Impact of a Photovoltaic System Installed at Universidad Jorge Tadeo Lozano, Colombia https://spast.org/techrep/article/view/242 <p>In recent years, the need to exploit alternative sources of energy has taken on great importance. Concern for sustainable development and the latent threat of climate change has generated a reason to change lifestyles dependent on fossil fuels [1]. In the international context, institutions and associations have established a consensus related to research related to the environment and energy. The use of energy sources from fossil fuels generates a high environmental impact. Multilateral treaty initiatives such as the Kyoto Protocol, the Copenhagen Conference, and recently the XXI International Conference on Climate Change; commit industrialized countries to reduce greenhouse gas emissions. Furthermore, within the framework of the objectives of the Kyoto Protocol, the signatory countries undertook to promote the supply of energy through renewable energy sources and thus reduce the use of fossil resources, which helps mitigate the environmental impacts of greenhouse gas emissions [2]. Furthermore, electrical energy is required to satisfy many basic human needs: lighting, communication, mobility, and comfort; therefore, it is necessary to ensure social, environmental, and energy sustainability through the change to renewable technologies [3]. The electric power generation sector alone represents 25% of greenhouse gas emissions worldwide, and this is due to the need to meet the energy demand of a growing population [3]. Currently, there are 7,000 million inhabitants on earth, and it is estimated that by 2050 the figure will reach 9,000 million, thus demanding an increase in energy supply, calculated in the order of 30% over current levels, based on estimates of the Energy Information Administration - EIA [4].</p> <p>This research analyzed the environmental loads of the photovoltaic power generation system installed in the "Alberto Lozano Salmonelli Biosystems Center" of the Jorge Tadeo Lozano University using the Life Cycle Analysis (LCA) method using the Simapro 7.1 Software. The target renewable energy system was divided into three stages: installation, operation, and final disposal, where two scenarios were included. The results show that the installation phase generates the most significant impact on the system. However, applying methods such as disassembly and use decreases environmental impacts in the final disposal stage.</p> <p>Figure 1 shows the 5.7 kW PV system installed in the Biosystems Center of the Jorge Tadeo Lozano University. Figure 2 shows the performance of the system for 2019. Figure 3 presents the results of the life cycle analysis of the system.</p> Andres Julian Aristizabal Copyright (c) 2021 Andres Julian Aristizabal 2021-09-11 2021-09-11 1 01 Synthesis, characterization and effect of Copper incapacitating nanostructured MoO3 flakes as anode electrode for Li-ion batteries. https://spast.org/techrep/article/view/547 <p>Abstract</p> <p>Molybdenum oxide (MoO<sub>3</sub>) is a very prominent and promising anode electrode material for Li-ion battery due to its high specific capacity, less toxicity and low cost. Nevertheless, undoped MoO<sub>3</sub> usually suffers from unsatisfactory cyclic stability, low rate capability and poor conductivity [<a href="#_ENREF_17">1]</a>. Hence in the present work the different weight percentage (0, 2, 4, 6, 8 and 10 wt %) of Copper (Cu) incapacitated MoO<sub>3</sub> flakes were successfully green synthesized by combustion technique using ammonium heptamolybdate tetrahydrate as precursor, Shorea Robusta leaves extract as fuel and Copper nitrate trihydrate as dopant. The synthesized different weight percentage (wt%) of &nbsp;nanostructured Cu doped MoO<sub>3</sub> flakes were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), morphology studies were carried by Scanning electron microscopy (SEM) equipped with EDAX and High resolution transmission electron microscopy (HRTEM), the band gap was determined by UV-Visible Diffused reflectance spectroscopy (UV-Vis DRS) and impedance was determined by Electrochemical impedance spectroscopy (EIS). XRD analysis reveals that the prepared Cu doped MoO<sub>3</sub> material exhibits orthorhombic structure with high crystallanity nature and the XRD pattern show a shift in diffractive peak towards lower diffractive angle as the Cu dopant wt% increases. FT-IR analysis shows the presence of stretching bond between molybdenum and oxygen atom (Mo=O) at 993cm<sup>-1 </sup>[2]. From SEM morphological analysis flake like structure was observed [3-4]. The HRTEM studies shows d-spacing of 0.20 nm for 6 wt % Cu doped MoO<sub>3</sub> flakes with irregular shapes. UV-DRS studies revealed the band gap varies from 3.15 eV to 3.36 eV for different wt% Cu doped MoO<sub>3</sub> flakes and for 6 wt % Cu doped MoO<sub>3</sub> flakes obtained band gap is less (3.15 eV). EIS studies reports the impedance varies from 180 Ω to 300 Ω is shown in &nbsp;&nbsp;&nbsp;fig.1 and values are tabulated in table 1. The band gap and impedance results shows good conductivity for 6 wt % Cu doped MoO<sub>3</sub> flakes compared to other synthesized wt% nanostructured Cu doped MoO<sub>3</sub> flakes. The improved band gap and impedance were observed for 6 wt % Cu doped MoO<sub>3</sub>. Thereby the synthesized 6 wt % Cu doped MoO<sub>3</sub> flakes were selected and configured as anode electrode material for Li-ion battery. The Li-ion battery performances; charge/discharge profile and Coulombic efficiency of 0 and 6 wt % Cu doped MoO<sub>3</sub> were analysed&nbsp; for 100 cycles. The first cycle discharge capacity of 0 and 6 wt % Cu doped MoO<sub>3</sub> were 1149 and 1718 mAh/g respectively. The hundredth cycle discharge capacity of 0% and 6 wt % Cu doped MoO<sub>3</sub> were 254 and 780 mAh/g respectively. The charge/discharge profile shows good specific capacity and cycalibilty for 6 wt % Cu doped MoO<sub>3</sub> flakes than 0 wt % Cu doped MoO<sub>3</sub>.</p> <p><em>Keywords</em>: MoO<sub>3</sub>; Flakes; Doping; Shorea Robusta; Combustion; Band gap;</p> <p><em>&nbsp;</em></p> <p><strong>Fig. 1. EIS spectra of different concentration Cu doped MoO<sub>3</sub>.</strong></p> <p><em>&nbsp;</em></p> <table> <tbody> <tr> <td width="48"> <table width="100%"> <tbody> <tr> <td> <p>A</p> </td> </tr> </tbody> </table> &nbsp;</td> </tr> </tbody> </table> <p>Table 1<strong>&nbsp; </strong></p> <table> <tbody> <tr> <td colspan="2" width="320"> <p><strong>Samples </strong></p> </td> <td width="125"> <p><strong>Impedance (Ω)</strong></p> </td> </tr> <tr> <td width="319"> <p>2% Cu doped MoO<sub>3</sub> nanoparticles</p> </td> <td colspan="2" width="126"> <p>182.97</p> </td> </tr> <tr> <td width="319"> <p>4% Cu doped MoO<sub>3</sub> nanoparticles</p> </td> <td colspan="2" width="126"> <p>227.68</p> </td> </tr> <tr> <td width="319"> <p>6% Cu doped MoO<sub>3</sub> nanoparticles</p> </td> <td colspan="2" width="126"> <p>180.56</p> </td> </tr> <tr> <td width="319"> <p>8% Cu doped MoO<sub>3</sub> nanoparticles</p> </td> <td colspan="2" width="126"> <p>195.71</p> </td> </tr> <tr> <td width="319"> <p>10% Cu doped MoO<sub>3</sub> nanoparticles</p> </td> <td colspan="2" width="126"> <p>194.55</p> </td> </tr> </tbody> </table> HARINI R raj LATHA H K E Copyright (c) 2021 HARINI R raj, LATHA H K E 2021-09-16 2021-09-16 1 01 Improvement in the Performance of Perovskite Solar Cells by Reducing Defect Density with Antisolvent Treatment https://spast.org/techrep/article/view/2213 <p>In this work, we have investigated the influence of chlorobenzene antisolvent treatment on perovskite film formation in inverted planar perovskite solar cells. Herein, we report the formation of smooth, pin-hole free flat homogeneous perovskite film by one-step antisolvent induced crystallisation method for the device configuration of ITO/PEDOT:PSS/ CH3NH3PbI3 xClx/PC71BM/Al. The process involves spin-coating of perovskite precursor followed by addition of antisolvent liquid (chlorobenzene) in the mid of the spin-coating process. This antisolvent treatment process has shown an effective way to improve the morphology of the perovskite film as well as photovoltaic performance of the PSCs. The significant superior photovoltaic performance has been obtained with antisolvent treated PSCs having average PCE ~ 11.5% as compared to conventional spin-coated planar PSCs with an average PCE ~ 8% as shown in Fig 1. <br>In order to investigate this enhanced photovoltaic performance in antisolvent assisted PSCs, systematic investigations using optical absorption, IPCE, electroluminescence (EL), electrochemical impedance spectroscopy (EIS), capacitance-voltage (C-V), XRD, and scanning electron microscopy (SEM) have been carried out. <br>An enhanced absorption in antisolvent treated films in 400-650 nm wavelength range was observed which was also supported by IPCE measurements. We studied the electroluminescence (EL) emission spectrum for distinguishing the recombination losses. Conventional PSCs showed an increased loss due to non-radiative recombination as compared to antisolvent treated PSCs. This increased recombination loss was confirmed with electrochemical impedance spectroscopy (EIS) and Mott-Schottky (MS) analysis. Capacitance-voltage (C-V) measurement using MS plot has been used for distinguishing the effects taking place in bulk of the active layer and those occurring at the interface of perovskite/ETL or HTL [1,2]. We found lower built-in potential (Vbi) of 0.77 V and higher defect density (N) of 24.6 x 1016 cm-3 for conventional planar PSCs as compared to antisolvent treated PSCs with Vbi ~ 1.135 V and N ~ 11.1 x 1016 cm-3 [3]. The higher defects exert extra potential barrier and hinder the charge carrier’s extraction. It also induces trap-assisted recombination and reflects as lower Voc and PCE as in case of conventional PSCs. The lower trap density and higher Vbi results in lower non-radiative recombination which is beneficial to raise both the Voc and PCE for antisolvent PSCs. In EIS studies, we have found two signals in the form of arcs in Nyquist plot and in the form of peak in bode plot at 104-105 Hz and 1 Hz respectively. We found a good agreement between ideality factor (ηid) determined by two different methods viz. Sun-Voc (extracted from J-V curves) and Sun-RHF (extracted from EIS). Ideality factor of 1.64 and 2.28 has found for antisolvent treated and conventional PSCs respectively [4]. The higher ηid confirms the increased recombination loss in conventional PSC. <br><br>Fig. 1. Current density−voltage curves of devices fabricated with conventional and antisolvent treated PSCs. Inset shows the schematic diagram of the planar inverted perovskite device.</p> <p>The XRD measurements on the films revealed that antisolvent treatment causes improved crystallinity of perovskite structure and preferred crystal growth in (110) direction. SEM studies also confirmed the formation of smooth and pin-hole free perovskite film formation with antisolvent treated perovskite film. It is therefore concluded that the enhanced photovoltaic performance in antisolvent-assisted PSCs is attributed to smooth pin-hole free perovskite film morphology having lower defect density and recombination losses.</p> Deeksha Gupta Anil K. Chauhan Veerender Putta S. P. Koiry P. Jha Copyright (c) 2021 Deeksha Gupta, Anil K. Chauhan, Veerender Putta, S. P. Koiry, P. Jha 2021-10-03 2021-10-03 1 01 Water Management in Proton Exchange Membrane Fuel Cells https://spast.org/techrep/article/view/1555 <p>Most of the world’s energy requirements are fulfilled by fossil fuels alone since the second industrial revolution. Concurrently, fossil fuels are diminishing and greenhouse gas emissions are soaring at an exponential rate leading to adverse climatic conditions such as global warming. All these events have made it inevitable to look for alternatives to fossil fuels [1].</p> <p>Hydrogen is a clean and green alternative to fossil fuels which generated only water on combustion. The use of hydrogen as a fuel in the fuel cells is a viable solution. A fuel cell is a device that converts the chemical energy of the fuel directly to electricity with minimum loss of energy. Of the variety of fuel cells present in the market, the Polymer Electrolyte Membrane Fuel Cell (PEMFC) is a promising type. However, its economical commercialization is still a challenge due to certain perceptive shortcomings associated with it, such as water balancing in the fuel cell stack, flooding and dry out, etc [2]. Proton conductivity and activation overpotentials are influenced by the amount of water available in the polymer membrane. The protonic conductivity of the MEA diminishes when it is not properly humidified, resulting in increased cell resistance and reduced durability. To prevent fuel cell deterioration and ensure good performance, a delicate balance between membrane drying and liquid water flooding must be maintained. The current density affects the generation of water at the cathode. Design of heater, flow channel, and gas diffusion layer plays a major role in water management [3].</p> <p>Even though a lot of research has been carried out on this topic, efficient water management remains elusive. This paper presents a comprehensive review of water transport/management, its effects on cell performance, and mitigation strategies of water flooding to increase the overall efficiency of the cell. It also highlights the gaps in water management and future advancements [4].</p> Ujwal Shreenag Meda Amrit Aman Iqra Arabia Ali Khan Copyright (c) 2021 Ujwal Shreenag Meda, Amrit Aman, Iqra Arabia Ali Khan 2021-09-30 2021-09-30 1 01 Effect of electrolyte on the performance of supercapacitors https://spast.org/techrep/article/view/413 <p>The significant increase in global economy and urbanization results in accelerated depletion of fossil fuel reserves as well as some serious environmental problems such as increased greenhouse gas emission, pollution etc. Thus, a paramount importance has been given to the development of zero-emission renewable energy technologies. In this regard, electrochemical energy storage devices such as supercapacitors [1-3] and batteries [4, 5] gain great research interest owing to their good efficiency, high stability, as well as non-toxic nature. However, the electrochemical supercapacitors are a preferred choice for applications that demands high power (electric vehicles, satellites, robots etc), rapid charging/discharging ability as well as long cycle life in comparison to batteries. For high performance of electrochemical supercapacitors, electrolytes play a very imperative role. A large variety of electrolytes, such as aqueous electrolytes, organic electrolytes, ionic liquids electrolytes, redox-type electrolytes and solid or semi-solid electrolytes have been investigated. In all electrochemical processes, the interaction among electrodes and electrolyte considerably influence the electrode-electrolyte interface state as well as the internal structure of active material. For instance, the matching between the electrolyte ion size and the pore size of carbon based electrode has a significant effect on the obtained specific capacitance. The pseudocapacitances from the carbon-based electrodes and transition metal oxides are also highly dependent on the type of electrolytes used [6, 7]. Moreover, the viscosity, boiling point and freezing point of the electrolytes highly influences the thermal stability as well as the operating temperature range of the electrochemical supercapacitors. It has also been observed that the aging and breakdown of electrochemical supercapacitor are also due to the electrochemical decomposition of the electrolyte used which may be due to the incompatibility of the electrolyte with the supercapacitor electrode material. Generally, the requirements for an ideal electrolyte includes a broad potential range, high ionic conductivity, good stability,&nbsp; wide operating temperature, highly compatible with the electrode material, non-volatility and low flammability, non-toxic as well as cost effective. Till now, there has been no single electrolyte that completely fulfils all the requirements of electrochemical supercapacitor device. For example, supercapacitor using aqueous electrolytes exhibits high conductivity as well as high specific capacitance but low energy density and poor cyclic stability. Organic electrolytes and ionic liquids usually have lower ionic conductivity. Solid-state electrolytes may shun the potential leakage problem of the liquid electrolytes, but they also exhibit low ionic conductivity. Therefore, the performance of the electrode material and hence the supercapacitor device depends highly on the selection of the electrolyte. As a result, the development of highly compatible electrolytes is very crucial for developing safe and high performance supercapacitors.</p> <p>This article reviews the progress in the electrolytes for electrochemical supercapacitors. The effects of electrolyte properties on the electrochemical performance of supercapacitors are also discussed along with the interaction among the electrolyte, electro-active material and inactive component (current collectors, binders, and separators). Various important challenges encountered along with their potential solutions for developing highly efficient electrolytes are also scrutinized.</p> Sonali Verma Copyright (c) 2021 Sonali Verma 2021-09-15 2021-09-15 1 01 Some Aspects of Transition Metal Oxide based Devices for Energy Management https://spast.org/techrep/article/view/2681 <p>The market for smart windows/glass is exponentially growing (projected 3.5 billion by 2024) with the evolving work culture as people are gradually spending more time in the indoors. One well-identified concern is energy wastage in commercial buildings that consume near forty percent of total supplied power and out of what more than thirty percent gets wasted through the windows. The “Energy and Buildings” document published by the <em>Centre for Science and Environment </em>identified two facts: rapid increase of Glass usage in buildings; and glazing of glass to be the most viable pathway for saving substantial amount of energy[2].</p> <p>Energy is essential to maintain and increase the standard of living. Energy saving are becoming more urgent because of its increasing demand day by day due to rising population. The use of energy is mostly dwelt with various sectors like industry, transport and in buildings especially it is utilized for heating, cooling, lighting and ventilation. As people spend their most of the time in indoor environment related to their carriers which tend to spend as much as energy for space cooling. One way to improve the situation with regard to energy and indoor comfort is to have building envelopes with variable throughput of visible light and solar energy. In line with these worldwide efforts, use of smart windows will significantly decrease the cost of air conditioning and sun shading, and simultaneously improve the indoor comfort with added decoration effect [1]. Such windows are mostly relying on the chromogenic technologies in which the optical properties can be changed in response to external signal.&nbsp; Chromogenic materials based on transition metal oxide (TMOs)&nbsp; can alter their optical properties via the application of some external stimuli like potential, temperature, light etc. Herein we demonstrated a facile, low cost, environment friendly technique to synthesis photochromic solution of WO<sub>3</sub>-PVP , V<sub>2</sub>O<sub>5</sub>- PVP composite. These solutions show good photochromic behavior under the irradiation of UV light 365nm with coloring time of 3s and bleaching time of 30mins with good kinetics. The major challenge in this solution is to make bleaching time lesser. This property of the composite in altering the optical properties pave the way for real time applications like smart displays, smart windows, glasses, optical memory devices, security systems.</p> <p><strong>Take away Message:</strong></p> <ul> <li>Chromogenic technologies in smart materials help to save a good amount of energy in HVAC.</li> <li>Among the chromogenic systems, photochromic systems are simple, great solar modulation especially among infrared region, automatic modulation depends on photo excitation without any external energy supply accessories[3].</li> <li>The result show good photochromic behaviour with less switching time for real time applications.</li> </ul> Amritha P Copyright (c) 2021 Amritha P 2021-10-21 2021-10-21 1 01 Energy recovery from palm leaflet waste by using anaerobic digestion and thermochemical conversion https://spast.org/techrep/article/view/881 <p>Due to the increasing population around the globe, requirements for energy are increasing day after day. The conventional approaches for energy production may not be sufficient to meets these requirements. This necessitates energy production from different renewable sources through suitable techniques. In the present study, energy recovery from palm leaflet waste (PLW) in Morocco was examined. PLW is the by-product of palm farms and is usually burnt in the field or barren lands. This causes the emission of carbon dioxide (CO2) and of other air pollutants, as well as the outbreak of fires in the fields, which destroy a large number of palms. The purpose of this study was to identify and calculate the theoretical energetic potential (Ep) that can be recovered from PLW using anaerobic digestion (AD) and thermochemical conversion (TC) i.e. combustion. To estimate the theoretical heating value for TC, an elementary analysis was used. The processes of AD and TC on PLW led to the generation of energetic potentials (EP) of 69.81 GWh/y and 235.5 GWh/y, respectively. This work could be used as a guide by the countries having the same nature of biomass to make a preliminary energy study. This would ultimately lead to the development of processes that can end the energy crisis worldwide.</p> Omar Kerrou Copyright (c) 2021 Omar Kerrou 2021-09-16 2021-09-16 1 01 Anti- solar panels https://spast.org/techrep/article/view/914 <p>A report is presented that contains the development of a research project of the applied type<br>that lies in the contribution of innovation products that transcend the use of Renewable Energy<br>(RE). Through a methodology for the development of technological prototypes [1], an energy<br>diversification is obtained, which seeks to reduce the pollution caused by fossil fuels, so as<br>to avoid the environmental deterioration that has been generated in the world constantly over<br>the years [2].<br>This innovation suggests as a hypothesis that alternative energies and in particular the use<br>of solar panels, which have benefited in different areas: governmental, business, social, family<br>and economic, entails a technological impact on the use of antisolar panels, generating clean<br>energy that achieves the operation of different machines and circuits that together with<br>conventional solar panels, antisolar panels create a sustainable energy source that can be<br>used during the course of the days, using another type of device called a thermoradiative cell,<br>which generates energy by radiating heat to the environment, in order to convert more<br>electrical energy between both mechanisms [3], thus opting for a alternative to minimize<br>pollution to the environment.<br>The importance of the development of technological systems, which are efficient and safe and,<br>which contribute to the conservation of existing biodiversity, in such a way that resources<br>prevail for future generations, avoiding the destruction of ecosystems, promotes a research<br>project aware of the minimization of environmental impact. Using anti-solar panels that capture<br>and transform natural energy (solar and absence of light) into electrical energy, will allow<br>conditions to be created to create economic, public safety, ecological and environmental<br>strategies, since the follow-up of the suggestions of the 2030 Agenda will be made explicit<br>through five Sustainable Development Goals: affordable and non-polluting energy, industry,<br>innovation and infrastructure, sustainable communities and cities, life of terrestrial ecosystems<br>and climate action [4].<br>The improvement through technology based on the mechanism used by the panels to<br>transform the captured sunlight into electrical energy will allow the panels to also transform<br>the energy captured from the absence of light, and therefore, more electrical energy will be<br>generated for industrial, public and domestic use. For the design of the prototype of the antisolar panel, a study was analyzed through different periods. Initially, the selection of the place<br>of the application of the system was made considering the size of the device and the<br>thermoradiative effect obtained [5].<br>The necessary criteria for the development of the project are previously established and the<br>joint planning of the prototype hardware is carried out so that the objectives considered are<br>achieved. The construction of the prototype is divided into two phases: mechanical design and<br>electronic system of which its operation consists. Subsequently, the development for the<br>operation is specified for each of the elements used in its elaboration, which make up both the<br>panel in its physical structure, as well as the photovoltaic solar module, charge regulator as<br>well as the battery or accumulator and of course the inverter, which has as operability to&nbsp;</p> <p>convert the direct current captured by the panels that capture the energy of light and the<br>absence of light, according to the time of day.<br>The social impact that the innovation of anti-solar panels entails, leads to the aspect of public<br>safety: streets, jobs and even homes and, in the medium and long term, it is considered that<br>there are savings in the lighting service. The involvement of both companies and the common<br>citizen, to address the seriousness of the situation caused by traditional technology, is the<br>basis for also generating social impact, since they serve as special data and are subject to<br>programs with defined strategies, causing, therefore, satisfaction in both roles and benefiting<br>the environment by taking care of the environment by generating energy in an alternative way.</p> PEDRO URIEL AZUA GALVAN Copyright (c) 2021 PEDRO URIEL AZUA GALVAN 2021-09-16 2021-09-16 1 01 Design of Solar Cell Temperature Based Single Parameter Model of PV Modules https://spast.org/techrep/article/view/393 <p><span style="font-weight: 400;">Single parameter models are very useful for the focused study of the impact of a particular parameter on a complex phenomenon while holding all other influencing parameters at some standardized constant values. Such models form the basis of many studies of systems that require performance estimation and prediction with due parametric analysis. For example, if the performance a system degrades by a certain percentage, its impact on the overall performance in the long run is often required to be estimated.</span></p> <p><span style="font-weight: 400;">This paper aims to develop a single parameter model of a solar photovoltaic module. The output power and the efficiency of PV cells are primarily governed by cell temperature. In India, the range of highest cell temperature generally lies between 50°C to 75°C in different seasons and impacts their performance negatively. The increase in temperature also causes the development of thermal stresses in the panel and affects its life span.&nbsp;</span></p> <p><span style="font-weight: 400;">The authors have studied several models available in the literature and deeply examined twelve of these. However, none of these models have discussed the temperature coefficients in detail which is the most important part of the temperature modeling. Further, the authors have often not disclosed the mathematical derivation and appear to arrive at the proposed equations empirically. Generally, no explanation has been provided about the constants and their particular values.&nbsp;</span></p> <p>&nbsp;</p> <p><span style="font-weight: 400;">Hence, in this paper, a methodology has been proposed to design a simple single parameter model of a PV module based on cell temperature that can be used under changing operational conditions. The methodology has been validated by developing models for three different modules widely used by researchers. These include Kyocera KC 200GT [29=1], Trina TSM 290PC/PA [30=2], and Jakson JPH 24X330 [31=3]. The technical specifications of these modules have been taken from the data sheets provided by the respective manufacturers. The cell temperature is estimated by employing the mathematical modelling equations proposed by Skoplaki and Palyvos [8=4].</span></p> <p><span style="font-weight: 400;">The simulation of these models of PV module is carried out using MATLAB and estimates of voltage at the maximum power point, current at maximum power point and hence power at maximum power point have been obtained for temperature ranges from 250C to 750C in steps of 50C, at constant solar radiation of 1000W/m</span><span style="font-weight: 400;">2</span><span style="font-weight: 400;"> as shown in Table 1.</span></p> <p><span style="font-weight: 400;">Table 1 Analysis of the Accuracy of the Proposed Model</span></p> <table> <tbody> <tr> <td rowspan="2"> <p><strong>Temperature</strong></p> <p><strong>(</strong><strong>0</strong><strong>C)</strong></p> </td> <td rowspan="2"> <p><strong>Power output from the Proposed Model</strong></p> </td> <td colspan="3"> <p><strong>% Accuracy of the Proposed Model with respect to Referred Models</strong></p> </td> </tr> <tr> <td> <p><strong>Evans and Florschuetz’s Model [5]</strong></p> </td> <td> <p><strong>Parretta et al.’s Model [6]</strong></p> </td> <td> <p><strong>Al-Sabounchi’s Model [7]</strong></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">25</span></p> </td> <td> <p><span style="font-weight: 400;">290.242</span></p> </td> <td> <p><span style="font-weight: 400;">99.92</span></p> </td> <td> <p><span style="font-weight: 400;">99.92</span></p> </td> <td> <p><span style="font-weight: 400;">99.92</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">30</span></p> </td> <td> <p><span style="font-weight: 400;">284.901</span></p> </td> <td> <p><span style="font-weight: 400;">99.70</span></p> </td> <td> <p><span style="font-weight: 400;">99.09</span></p> </td> <td> <p><span style="font-weight: 400;">99.25</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">35</span></p> </td> <td> <p><span style="font-weight: 400;">278.798</span></p> </td> <td> <p><span style="font-weight: 400;">99.75</span></p> </td> <td> <p><span style="font-weight: 400;">98.5</span></p> </td> <td> <p><span style="font-weight: 400;">98.82</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">40</span></p> </td> <td> <p><span style="font-weight: 400;">271.938</span></p> </td> <td> <p><span style="font-weight: 400;">99.92</span></p> </td> <td> <p><span style="font-weight: 400;">98.16</span></p> </td> <td> <p><span style="font-weight: 400;">98.64</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">45</span></p> </td> <td> <p><span style="font-weight: 400;">264.586</span></p> </td> <td> <p><span style="font-weight: 400;">99.38</span></p> </td> <td> <p><span style="font-weight: 400;">97.99</span></p> </td> <td> <p><span style="font-weight: 400;">98.64</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">50</span></p> </td> <td> <p><span style="font-weight: 400;">255.94</span></p> </td> <td> <p><span style="font-weight: 400;">98.31</span></p> </td> <td> <p><span style="font-weight: 400;">98.29</span></p> </td> <td> <p><span style="font-weight: 400;">99.14</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">55</span></p> </td> <td> <p><span style="font-weight: 400;">246.803</span></p> </td> <td> <p><span style="font-weight: 400;">99.97</span></p> </td> <td> <p><span style="font-weight: 400;">99.98</span></p> </td> <td> <p><span style="font-weight: 400;">99.99</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">60</span></p> </td> <td> <p><span style="font-weight: 400;">236.906</span></p> </td> <td> <p><span style="font-weight: 400;">99.95</span></p> </td> <td> <p><span style="font-weight: 400;">99.99</span></p> </td> <td> <p><span style="font-weight: 400;">99.99</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">65</span></p> </td> <td> <p><span style="font-weight: 400;">226.250</span></p> </td> <td> <p><span style="font-weight: 400;">99.92</span></p> </td> <td> <p><span style="font-weight: 400;">99.99</span></p> </td> <td> <p><span style="font-weight: 400;">99.97</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">70</span></p> </td> <td> <p><span style="font-weight: 400;">214.836</span></p> </td> <td> <p><span style="font-weight: 400;">99.90</span></p> </td> <td> <p><span style="font-weight: 400;">99.97</span></p> </td> <td> <p><span style="font-weight: 400;">99.95</span></p> </td> </tr> <tr> <td> <p><span style="font-weight: 400;">75</span></p> </td> <td> <p><span style="font-weight: 400;">202.663</span></p> </td> <td> <p><span style="font-weight: 400;">99.86</span></p> </td> <td> <p><span style="font-weight: 400;">99.94</span></p> </td> <td> <p><span style="font-weight: 400;">99.92</span></p> </td> </tr> </tbody> </table> <p>&nbsp;</p> <p><span style="font-weight: 400;">The accuracy of all the proposed models has been found to be better than 98% as shown in Table 1. This methodology will be useful for the design of simplified models for accurate prediction of the power output of PV modules for different operating temperatures. It is also expected to be useful for researchers wherever manufacturers of commercial PV modules do not specify the coefficient of temperature.</span></p> Harish Khyani Copyright (c) 2021 Udit Mamodiya 2021-09-15 2021-09-15 1 01 Investigation into performance of Battery- Supercapacitor Hybrid System https://spast.org/techrep/article/view/1928 <p>The world economy is becoming aware of the impact that conventional vehicles can have on the environment. The adoption of electric vehicles has become a growing trend in recent years. Consequently, extensive research has been carried out to improve the performance of electric vehicles. The existing battery technologies do not completely match the requirements of an electric vehicle's power consumption, which is one of the primary disadvantages of electric vehicles. When an electric vehicle demands a surge of power during acceleration, the battery pack cannot be discharged quickly enough to meet this requirement. Supercapacitors are electrochemical cells that are the most versatile devices widely used for the delivery of electrical energy in a short time and in arenas that demand long shelf life. They are of similar architecture to batteries but with higher power density, longer cycle life, and good transient charge and discharge performance. While batteries generally lose their efficacy after a few hundred charge-discharge cycles, supercapacitors may last for over a million cycles.&nbsp; However, they cannot be used as the power source of electric vehicles since they have low energy density as compared to batteries [1]. The development of supercapacitors is a huge market requirement, and long-term progress is needed for successful advancement and commercialization. One such development is a hybrid combination of batteries and supercapacitors, which help in taking advantage of both high specific power for better acceleration and high specific energy to extend the range of the vehicle. The use of a supercapacitor pack in conjunction with a battery allows for considerable reductions in battery cell heat output while preserving or even decreasing the weight of the energy storage system. Supercapacitors have a significant impact on the efficiency of energy storage systems in electric vehicles and thereby help increase the vehicle's range [2]. They also play a major role in decreasing the peak current of the battery pack, thereby extending the lifetime of the battery pack. The most popular choice for energy storage recuperated by regenerative braking is batteries; however, the high-power transient charging that can occur during braking is troublesome for batteries and can cause considerable deterioration, reducing performance and lifespan. In comparison to batteries, the high-power density of supercapacitors allows hybrid energy systems to absorb the power generated during braking more effectively [3]. Meanwhile, the adoption of supercapacitors is also facing challenges such as technical problems, establishing electrical parameter models, consistency testing, and establishing industry standards. It is also important to balance the energy and distribute the battery load efficiently to maximize the benefits of the hybrid energy storage system. Hybrid energy systems will benefit the electric vehicle industry by overcoming difficulties such as range and battery aging. Simulation results show that supercapacitors help in increasing the vehicle's range by up to 20% and decrease battery's peak current by up to 80% [4-5]. In this paper, the challenges and advantages of hybrid energy systems are discussed in detail. For the development of hybrid systems, this paper provides insight into the topologies and various energy management methods to enhance the hybrid energy system.</p> Shashwat M.A Sameer Keshavan Alwaaz Ahmad Copyright (c) 2021 Shashwat M.A, Sameer Keshavan, Alwaaz Ahmad 2021-10-09 2021-10-09 1 01 Poly Neutral Red for Electrocatalytic Hydrogen Evolution Reaction https://spast.org/techrep/article/view/582 <p>&nbsp;Electrocatalytic hydrogen evolution reaction (HER) is a key process for conversion of renewable electricity to storable hydrogen and is crucial to achieve sustainable energy system. HER currently needs nanoparticles of precious metals as electrocatalysts. Development of alternative catalysts based on abundant materials is therefore necessary. Recently, certain conductive polymers exhibited a high catalytic activity towards HER, as they possess hydrogen bonding sites for stabilization of reaction intermediates <sup>[1,2]</sup>. Neutral red (NR) is a phenazine dye that has a hydrogen-bonding amino group and can be polymerized as it is an analogue of aniline. We have studied synthesis of poly neutral red (PNR) by oxidative chemical vapor deposition (oCVD) and electropolyerization deposition (EPD) to evaluate their HER electrocatalysis.</p> <p>&nbsp;F-doped Tin Oxide (FTO, Asahi Glass) and Carbon felt (CF, SIGRATHERM® GFA5) were used as substrates. 3 zone tubular furnace was employed for oCVD in which NR vapor was oxidized by sulfuric acid at 325°C under N<sub>2</sub> stream. EPD was performed by potential cycling between -0.2 and 1.2 V (vs. Ag/AgCl) for 50 times in a 5 mM NR - 0.1 M H<sub>2</sub>SO<sub>4</sub> aqueous solution under N<sub>2</sub>. Polyaniline (PANI) was also obtained by EPD for comparison. The samples were characterized by infrared spectroscopy (IR), and UV-visible spectroscopy (UV/Vis). The HER catalysis was evaluated by linear sweep voltammetry (LSV) in a 1 M trifluoromethanesulfonic acid (TfOH) under N<sub>2</sub>.</p> <p>&nbsp;Although both PANI and PNR were nicely obtained by EPD, the CVs during the film growth significantly differed (Fig. 1). An irreversible anodic peak marked as IV is initially seen for oxidation of aniline to trigger its polymerization to PANI. Then, multiple redox peaks marked as I, II, III continue to grow during the CV scans, which are caused by proton-coupled reversible redox of PANI. On the other hand, an irreversible anodic peak II and reversible couple I are seen for NR. While oxidation of NR results in formation of PNR associated with slight decrease of the magnitude of II, the couple I should be proton-coupled reversible reduction of NR, which gradually become irreversible. It already is a sign of catalytic HER by PNR. It is important to note that no redox peaks of PNR are seen as those of PANI.</p> <p><img src="https://spast.org/public/site/images/yuya-harada/fig1.jpg" alt="Fig.1. CVs during EPD of (a) PANI and (b) PNR at 50 mV/s in a 5 mM monomer – 0.1 M H2SO4 on FTO for 50 cycles (Red initial to Blue final)." width="800" height="381"></p> <p><strong>Fig.1.</strong> CVs during EPD of (a) PANI and (b) PNR at 50 mV/s in a 5 mM monomer – 0.1 M H<sub>2</sub>SO<sub>4</sub> on FTO for 50 cycles (Red initial to Blue final).</p> <p>Although significantly broadened, the absorption spectrum of PNR-EPD preserves the character of that of NR monomer, to make it appear dark red (Fig. 2a). On the other hand, PNR-oCVD was black with a featureless spectrum. The FTIR of PNR-EPD also show peaks from the C=C and C=N stretching of the ring system, which are almost in the same positions as those for NR, whereas they are greatly shifted towards shorter wavenumbers for PNR-oCVD, suggesting complete change of the chemical structure during oCVD (Fig. 2b). Both PNR samples, however, show additional peaks assignable to HSO<sub>4</sub><sup>-</sup> or SO<sub>4</sub><sup>2-</sup> introduced as dopant to make them conductive.</p> <p><img src="https://spast.org/public/site/images/yuya-harada/fig2.jpg" alt="Fig.2. Spectroscopic characterizations: (a) Normalized UV-vis absorption spectra and (b) FTIR spectra of NR, PNR-oCVD, PNR-EPD and PANI. (●: C=C or C=N stretching, ■: s CH3, ▲: HSO4- / SO42- stretching)" width="800" height="318"></p> <p><strong>Fig.2. </strong>Spectroscopic characterizations: (a) Normalized UV-vis absorption spectra and (b) FTIR spectra of NR, PNR-oCVD, PNR-EPD and PANI. (●: C=C or C=N stretching, ■: δ<sub>s</sub> CH<sub>3</sub>, ▲: HSO<sub>4</sub><sup>-</sup> / SO<sub>4</sub><sup>2-</sup> stretching)</p> <p>The catalytic activity was in the order of PNR-EPD, PNR-oCVD and PANI with the HER overpotential (<em>η</em> for 10 mA cm<sup>-2</sup>) of 268, 379 and 590 mV, respectively (Fig. 3a). The best performing PNR-EPD also resulted in the largest exchange current density (<em>i</em><sub>0</sub>) and the smallest slope of 0.321 mA cm<sup>-2</sup> and 174.2 mV dec<sup>-1</sup>, respectively, from the Tafel plot (Fig. 3b), which are among the top reported for conductive polymer catalysts <sup>[1,2]</sup>. The poor HER catalytic activity of PANI is to be mentioned, since high conductivity and proton exchanging capabilities are expected for PANI. Stable reversible redox of PANI as seen in Fig. 1 is an indication of stabilization and localization of additional charge by protonation, which is not irreversibly transferred to proton to yield H<sub>2</sub>. On the other hand, the extra charge cannot be stabilized in the structure of PNR but rather is transferred to achieve HER. In order for the polymers to be catalytically active, we need to seek for polymers which are conductive as well as hydrogen-bonding, but not redox active.</p> <p><img src="https://spast.org/public/site/images/yuya-harada/fig3.jpg" alt="Fig.3. HER catalytic activity evaluation: (a) Liner sweep voltammogram (10 mV s−1) and (b) Tafel plot of PNR-EPD and PNR-oCVD as compared to PANI, CF (blank control) in 1 M TfOH electrolyte." width="800" height="367"></p> <p><strong>Fig.3.</strong> HER catalytic activity evaluation: (a) Liner sweep voltammogram (10 mV s−1) and (b) Tafel plot of PNR-EPD and PNR-oCVD as compared to PANI, CF (blank control) in 1 M TfOH electrolyte.</p> Yuya Harada Daiki Kono Philipp Stadler Tsukasa Yoshida Copyright (c) 2021 Yuya Harada, Daiki Kono, Philipp Stadler, Tsukasa Yoshida 2021-09-19 2021-09-19 1 01 Morphological, optical and photoelectrochemical properties of ZnS/CZTS QDs modified α-Fe2O3 Thin Films https://spast.org/techrep/article/view/864 <p>Quantum Dots (QDs) have tremendous potential for utilizing solar energy due to their high extinction coefficient and tunable bandgap on account of quantum confinement effect. Till date, many QDs like PbS, CdS, CdSe, CdTe have been widely studied in photoelectrochemical (PEC) generation of hydrogen [1]. All these QDs are highly toxic in nature which demand a need of alternative green QDs. In this view, Cu<sub>2</sub>ZnSnS<sub>4</sub>&nbsp;(CZTS) QDs has come up with its low cost and environment-friendly nature. They are widely known to be a good photo-absorber as they possess large absorption coefficient (up to 10<sup>5</sup> cm<sup>−1</sup>) and its bandgap lies in visible region of solar spectrum which makes them useful with other metal oxide for harnessing light effectively [2]. In PEC, metal oxides are old gems of the field and widely explored which require modification as they lack with some of the desired properties. The main considerations for the design of a PEC material are band structure, quantum efficiency, and resistance to both photocorrosion and corrosion in an aqueous environment. In order to achieve highly efficient PEC system, α-Fe<sub>2</sub>O<sub>3</sub> has been sensitized with CZTS QDs. Since, hydrothermal synthesis of CZTS QDs produces defect in it [3] so this system was coated with ZnS layer as a defect passivation layer. The band edges of this system are favorable for easy transfer of the carriers. Hence, this investigation for the first time explores the possibility of using CZTS QDs to improve the properties of hematite (α-Fe<sub>2</sub>O<sub>3</sub>) thin film photoelectrode for PEC water splitting.</p> <p>The photoelectrode preparation includes the synthesis of CZTS QDs, α-Fe<sub>2</sub>O<sub>3</sub>, and ZnS. CZTS QDs were prepared by hydrothermal method using Cu(CH<sub>3</sub>COO)<sub>2</sub>, Zn(NO3)<sub>2</sub>, SnCl<sub>2</sub> and thiourea as precursors [4]. α-Fe<sub>2</sub>O<sub>3 </sub>thin films were prepared by sol-gel spin coating method using Fe(NO<sub>3</sub>)<sub>3</sub> [5] and sensitized by CZTS QDs by chemical bath deposition method. These films were then subjected to ZnS coating by successive ionic layer adsorption and reaction (SILAR) method [6]. These films were implemented as photoanode in photoelectrochemical cell for photoresponse measurements. XRD, TEM, SEM and UV- visible spectroscopy techniques were used to characterize these thin films for deeper analysis. The size of synthesized CZTS QDs was well within the quantum confinement regime as examined by TEM image. This confinement was also verified by examining the UV-Vis spectra of CZTS QDs as they showed more value of bandgap compared to bulk counterpart. The UV-Vis spectra of modified Fe<sub>2</sub>O<sub>3</sub> thin films showed the increased value of absorption over visible region. It was also analysed that the value of resistance was smaller for modified sample as compared to pristine. The photoelectrochemical studies were carried out in PEC cell in 1M NaOH under Xe lamp. Highest photocurrent density of 1.98 mA/cm<sup>2</sup> at 0.75 V/SCE was observed for ZnS/CZTS QDs modified α- Fe<sub>2</sub>O<sub>3</sub> film. This photocurrent is 9.9 times than that of pristine. An increase in photocurrent could be attributed to better light absorption ability and reduced resistance after modification. Applied bias to photon conversion efficiency was also calculated using open circuit potential value and found higher for modified sample.</p> Ashi Ikram M. Zulfequar Copyright (c) 2021 Ashi Ikram, M. Zulfequar 2021-09-16 2021-09-16 1 01 A Development of High-Capacity Organosulfur Cathodes for Li-ion Batteries – A DFT Study https://spast.org/techrep/article/view/372 <p>&nbsp;</p> <p>Lithium-ion batteries have dominated the portable electronics market and show great promise in large-scale applications such as smart grids and EVs. To date, commercial metal oxide cathodes like LiCoO<sub>2</sub>, LiFePO<sub>4</sub>, or LiNi<sub>x</sub>Mn<sub>y</sub>Co<sub>Z</sub>O<sub>2</sub>, are mainly used. However, ores and the resources of these metal oxides are very limited [1-3]. Several research groups focused on searching for a new generation of rechargeable lithium battery technologies with low cost using more environmentally friendly and naturally abundant materials. The advantages of organic materials are discussed in three aspects, compared with inorganic cathode materials [4]. Firstly, organic compounds consisting of a lightweight elements such as C, H, O, N, and S, which leads to low cost and high gravimetric energy density. Secondly, these materials are structurally flexible and stable. In contrast, inorganic materials undergo structural changes during dis/charging, leading to diffusion of alkali ions from the structure is very difficult. Thirdly, organic compounds can provide multiple lithiation sites leading to high energy densities and tune the redox properties by different substituents [5].</p> <p>The current study is focused on <strong><em>organo sulphur</em></strong> compounds as they possess high theoretical capacities due to multi-electron reactions of S-S bonds [6-7]. In the present study, DFT methods are applied to investigate the redox properties of several organosulfur organic compounds, namely benznesulphur, napthasulphur, anthrasulphur, tetrasulphur, petnasulphur, sumanenesulphur, and coronenesulphur. The computed redox properties are described based on the position of sulphur atoms on aromatic ring structures. Also, we understood the redox values are affecting as increasing the number of reacted lithiums. This investigation reveals an essential finding of mono sulphur, disulphide bond containing organic cathodes and their redox potential differences. Also, we calculated the theoretical performance of the highest redox potential exhibiting molecules. Finally, we found that pentacene sulfur has the highest redox potential and theoretical performance. It can take up to eight lithium per molecule, showing an exceptionally high charge capacity (409 mAhg<sup>-1</sup>). The lithiation mechanism of the Pentacene molecule is given in Figure (B), where the electron from Li-metal is added to the molecule followed by Li<sup>+</sup>-ion. A total of eight lithium reacted with the molecules showing a theoretical capacity of ~400 mAh/g. The complete findings will be presented.</p> saisrinu yarramsetti Copyright (c) 2021 saisrinu yarramsetti 2021-09-14 2021-09-14 1 01 Exploring The Thermoelectric Prospects of MoSe2 https://spast.org/techrep/article/view/2137 <p>The world will become more contemporary and automated, resulting in a significant increase in energy usage. We are primarily reliant on fossil fuels, which are finite in supply. The need for alternate and renewable energy resources is urgent. One approach to address this issue is to use thermoelectric energy. Thermoelectric energy is a type of green energy that is created by converting waste heat into electricity without causing any noise or harm to the environment. The conversion power or efficiency of any thermoelectric devices which is known by its figure of merit i.e. ZT= S<sup>2</sup>σ/k where S is thermopower, σ is electrical conductivity and k is thermal conductivity. TMDC’s are considered as a potential material for generating thermoelectricity because of their high Seebeck coefficients and low thermal conductivities.[1] MoS<sub>2</sub> has mostly been studied for thermoelectric response since the emergence of 2D materials [2-3]. Because selenides are more stable and resistant to oxidation than sulphides [4]. in this study, we explored MoSe<sub>2</sub>. Herein, we fabricated the MoSe<sub>2</sub> device which is characterized by Raman Spectroscopy and Atomic Force Microscopy. The thermopower has been investigated through 2ω method and found ~250uV/K at room temperature. The MoSe<sub>2</sub> shows n type semiconductor behaviour which can be confirmed through the figure 2(C) in which thermopower is increasing as back gate voltage is increasing in the positive side. Through this work, it can be concluded that MoSe<sub>2</sub> shows good thermopower and can be considered as a good thermoelectric material.</p> Chetan Awasthi WEN BIN JIAN WEN BIN JIAN S.S. Islam Copyright (c) 2021 Chetan Awasthi, JIAN, JIAN, Islam 2021-10-08 2021-10-08 1 01 Nanophase MnO2@ZIF composite as a High Performance Anode Material for Rechargeable Batteries https://spast.org/techrep/article/view/1572 <p>Li-ion technology has dominated the portable electronics market and is continually advancing; unfortunately, it falls short of the needs imposed by the powering of hybrid and ordinary electric vehicles<sup> [1]</sup>.Lithium-ion batteries have achieved extensive use in consumer devices due to their high power and energy density, long service life, and environmental friendliness when compared to other commonly used batteries. <sup>[2]</sup> Recently, transition metal oxides with Metal Organic Framework (MOF) composite nanomaterials have initiated intense research interest as electrodes for high performance energy storage devices.Among the various metal oxides, manganese dioxides (MnO<sub>2</sub>) in various forms prove to be a promising anode material for lithium-ion batteries. MOFs, a family of crystalline porous materials developed recently by combining metal ions with organic ligands. They are promising materials for a variety of applications based on its ability to construct fine-tunable and homogenous pore architectures. In this work, we report the synthesis of MnO<sub>2</sub>&nbsp;with zeolitic imidazole framework (ZIF) <sup>[4] </sup>electrochemical performance studies. MnO<sub>2</sub>@ZIF nanoparticles were successfully synthesized in two steps using hydrothermal method and followed by solvothermal method. MnO<sub>2</sub>@ZIF nanocomposites were characterized using X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR) and scanning electron microscopy (SEM). The electrochemical studies such as cyclic Voltametric, charge/discharge studies and electrochemical impedance (EIS) studies were conducted for MnO<sub>2</sub>@ZIF using CR2032 type coin cell. The obtained results indicate that MnO<sub>2</sub>@ZI has high potential for application in lithium-ion batteries.</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> <p>&nbsp;</p> Jeyakiruba Palraj Helen Annal Therese Copyright (c) 2021 Kiruba, Helen 2021-10-08 2021-10-08 1 01 Double heterojunction system of TiO2/ZnO/Cu3BiS3 for photoelectrochemical water splitting https://spast.org/techrep/article/view/1772 <p>In response to the increasing energy demand of modern generation, finding new sources of energy has become inevitable. Among all the intermittent renewable energy sources, hydrogen generation via photoelectrochemical (PEC) water splitting has been widely believed to be a cleaner route but the final word on this is yet to be said. Semiconductor plays an important role in the PEC configuration and all the researchers around the world are involved in preparing the most optimum semiconductor having the characteristics of narrow band gap, straddling band alignment with redox potential of water, economical, stable and have efficient photoresponse. In this connection, heterojunction of semiconductors has become an interesting format towards increasing the overall efficiency of the system by ensuring an effective charge separation and high current density. The purpose of this study was to determine the effectiveness of double heterojunction systems of Cu<sub>3</sub>BiS<sub>3</sub>, ZnO and TiO<sub>2</sub> in different combinations by arranging the materials in straddling band gap alignment.</p> <p>Cu<sub>3</sub>BiS<sub>3 </sub>(commonly known as Wittechenite) was chosen on account of being a p-type semiconductor, abundant in earth’s crust (band gap of 1.5 eV) having similar chemical properties as of CIGS (Copper-Indium-Gallium-Selenide). Other chosen material of interest viz. TiO<sub>2</sub> and ZnO are also non-toxic, stable materials and have an almost equivalent band gap of 3.2 eV.</p> <p>Hydrolysis-condensation mechanism involving Titanium butoxide and acetylacetonate was opted for synthesizing TiO<sub>2</sub> to make it stable and corrosion resistant. Titania so formed is in pure crystalline anatase phase. ZnO, on the other hand, was prepared in Wurtzite phase by using ethylene glycol which offered great ionic conductivity. L-cysteine was used as sulphur source and nitrates of Bismuth and Copper were used for synthesizing Cu<sub>3</sub>BiS<sub>3</sub>.Thin films were prepared via sol-gel method followed by spin coating deposition on conductive substrate of fluorine-doped tin oxide (FTO) to form double heterojunction of TiO<sub>2</sub>/ZnO/Cu<sub>3</sub>BiS<sub>3</sub> [TZC].</p> <p>Samples were subjected to electrochemical characterizations, optical analysis and UV-Vis spectroscopic analysis. Out of various opted combinations, TZC was found to be superior over the other investigated systems. It can be inferred from the UV – Vis analysis that TZC has higher absorbance relative to CZT [Cu<sub>3</sub>BiS<sub>3</sub>/TiO<sub>2</sub>/ZnO]. Subsequently, current density of 2.34 mA cm<sup>-2</sup> at 1 V vs. SCE in 0.1N NaOH electrolyte was achieved. Systematic investigation was performed for optimization of electrolyte pH vis-à-vis PEC performace and it was found that best results were achieved with pH range of 12.5 – 13.5. The results in detail would be discussed.</p> Runjhun Dutta Vanshita Goyal Manju Srivastava Rohit Shrivastav Copyright (c) 2021 Runjhun Dutta, Vanshita Goyal, Manju Srivastava, Rohit Shrivastav 2021-10-09 2021-10-09 1 01 HER via Volmer-Tafel route on borophene and its origin https://spast.org/techrep/article/view/1812 <p>H<sub>2</sub> gas as an alternate to hazardous fossil fuel is much significant as a solution to the green house gas problem. However, H<sub>2</sub> has to be produced, since it is not readily available from nature [1]. Hydrogen evolution reaction (HER) is a green method of producing H<sub>2</sub> gas. It is a half-cell reduction reaction where complete H<sub>2</sub> production can occur by either Volmer-Tafel pathway or Volmer-Heyrovsky pathway [2]. First step in both the pathways is common, the electrochemical step Volmer. It is the protonation of the surface, wherein the product is hydrogen adsorbed on the surface (H*). Adsorption free energy of Volmer step is a widely used parameter in theoretical works to find the HER activity of the corresponding catalyst. Tafel is a chemical step where a second H-atom is adsorbed near the pre-adsorbed H* and then H<sub>2</sub> evolves through recombination. Heyrovsky is an electrochemical recombination step where protonation occurs not on the surface but directly on the adsorbed H* and H<sub>2</sub> evolves. Tafel is a straightforward step to analyse theoretically and in calculating the respective activation barrier. Whereas theoretically modelling Heyrovsky is a complicated process. This is due to the complexity in modelling the solvent environment that has direct influence on the calculated activity.</p> <p>Platinum is the most efficient catalyst for HER with H<sub>2</sub> production occurring through V-T pathway [3]. The rarity and cost of platinum prevents it from used as a commercial catalyst thus demanding the search for a feasible catalyst. Density Functional Theory (DFT) based approach is a vital tool in investigating properties of a material and screening it for the required catalytic activity[4–6]. It serves as a precursor for experimental investigation by providing vital insights required. Borophene is a 2D analogue of boron that has been a recent addition to the 2D materials. It is explored for its role in multiple applications [7,8]. Additionally, it shows polymorphism with varying vacancy concentrations [9]. Metallic nature of borophenes make them a possible candidate as catalyst for HER. In this work, we use DFT based first principles approach, to investigate the HER activity of four borophene analogues. Based on the stability studies and experimentally synthesized sheets, we have selected four borophenes namely β<sub>12</sub>, α<sub>1</sub>, χ<sub>3 </sub>and β<sub>1 </sub>(Shown in Figure 1). Initially, the hydrogen adsorption free energy (DGH*) on all the possible active sites were investigated. It is found that pristine sheets shows high activity with DGH* (0.04 eV) that can be compared with that of platinum (0.09 eV). Further, free energy for the Tafel step is investigated considering the most active site for the first H-atom adsorption along with the barrier energy for H<sub>2</sub> recombination. Considering both free energy steps, α<sub>1 </sub>and β<sub>1</sub> are relatively good HER catalysts. Heyrovsky step is not investigated completely owing to the complexity in modelling the alkaline or acidic environment precursors and solvents. However, a simple barrier energy for H<sub>2</sub> formation from Hydronium ion is calculated. Overall, this work shows that borophene is good catalyst with high activity for HER and this work will serve as a basis in exploring further kinetic activities of HER on borophene and borophene based material.</p> Erakulan E.S Ranjit Thapa Copyright (c) 2021 Erakulan E.S, Ranjit Thapa 2021-10-09 2021-10-09 1 01 Combined Economic-Emission Dispatch of External Optimization Integrating Renewable Energy Resources Stochastic Wind and Solar https://spast.org/techrep/article/view/1852 <p>Economic dispatch in the standard power system network frequently prioritizes instant economic gains while overlooking the detrimental environmental effects of gas discharges from thermal power stations. Economic emission dispatch (EED) has received a lot of consideration in current years as a way to alleviate this shortage. The unpredictability and intermittence of renewable energy sources like wind and solar power are raising the difficulty of electric grid planning as renewable production penetration rises. This research proposes a modified MMOCE to improve dispatch efficiency with considerable renewable energy consumption. A congestion calculation method and a new external storage process are added to the traditional kernel function method to address multi-objective optimization issues. The energy and transportation sectors are two of the most significant producers of GHG emissions. Improved vehicle productivity is a partial answer, but to limit the rate of GHG emissions, it is important to use RESs in the network. It is, however, critical to evaluate the efficacy of each approach. In this research, the environmental and economic aspects of employing RESs will be examined using a mixture of generating cost and GHG emissions from the two businesses stated. To overcome the ELD problem, an enhanced PSO is employed. However, solutions for reducing time consumption for the high-dimensional ELD issue are not considered in this study.</p> Mayakannan Selvaraju C Shilaja G Nalinashini N Balaji K Sujatha Parveen Singla Copyright (c) 2021 Mayakannan Selvaraju, C Shilaja, G Nalinashini, N Balaji, K Sujatha, Parveen Singla 2021-10-08 2021-10-08 1 01 Comparative study of various DC-DC converter topologies for PV powered EV charging stations. https://spast.org/techrep/article/view/1177 <p>The urge for technology upgradation in automotive industry from conventional internal combustion engines (ICE) to Electric Vehicles (EV’s) is increasing deeply. One of the reasons behind this is their zero emissivity and thus reducing environmental effects [1]. EV’s also finds a solution for increasing fossil fuel costs and reduces the burden over fossil fuels. When it comes to renewable energy sources, typically to solar energy. Renewable energies like solar and wind energy systems are affluent and cheaper than fossil fuels [2]. The utilization of solar energy is maximized by advancements in power converter topologies. The EV application does not limits to electrics car it also finds major applications in aircrafts, marine vehicles etc. Wide range of converter topologies are also available for the power conversion, from DC to AC and DC to DC. Converters widely proposed ranges from the non-isolated topologies to isolated topologies, with voltage doublers, voltage cells, active clamping etc. An EV utilizes. The family of boost converters holds the task to boosting the electrical energy available at its input side to a higher output value. This paper aims to compare some of the boost converter topologies that are used in EV applications with solar photovoltaic powered charging stations. EV batteries can either be charged from AC grids or DC grids, islanded operation is also possible by using standalone PV power plants [3].</p> <p>Different boost topologies like conventional boost converter, Interleaved boost converter, boost converter with resonant circuit, and cascaded boost converter topologies are selected, their design and analysis conducted. By using MATLAB Simulink, the topologies are modelled for 30 – 50kW power and results are validated as shown in table 1. The comparative study is conducted on various parameters such as DC voltage gain, duty-cycle, efficiency, voltage stress, merits and demerits. Based on the design values, the best out of these topologies are identified as interleaved topology. The topology has the advantage of having reduced number of components and size reduction of passive components [4].</p> <p><img src="https://spast.org/public/site/images/mayavijayan/screenshot-2021-09-23-215114.png" alt="" width="455" height="218"></p> Maya Vijayan Copyright (c) 2021 Maya Vijayan 2021-09-24 2021-09-24 1 01 Modular Ultra-High Gain non-isolated DC-DC Converter for DC microgrid integrated with Fuel Cell https://spast.org/techrep/article/view/2117 <p>In recent years, DC microgrid integrated with energy sources like solar PV, fuel cell, batteries receives tremendous attention due to the depleting fossil fuel reserves, massive urge to reduce carbon footprint in the economic growth and initiatives for decentralized power distribution policy [1]. But the output voltage of fuel cell, solar PV are too low to integrate them directly with DC bus [2-4]. Hence it is essential to connect an intermediate high gain DC-DC converter between low voltage DC sources and DC bus [5]. Both isolated and non-isolated DC-DC converters can effectively use for this purpose. The voltage gain of the isolated converter can easily be enhanced by increasing transformer turns ratio. But, non-isolated converters with high voltage gain capability are preferred over isolated converters because of its compact size [6]. This paper presents a new ultra-high gain non-isolated DC-DC converter with modular structure for DC microgird system integrated with fuel cell. This converter is developed by judicially combining both switched inductor and switched capacitor techniques as gain extension network. Integration of both passive switched inductor (SI) and switched capacitor (SC) techniques in the adopted circuit for ultra-high voltage gain evolves into a hybrid modular structure with extendable gain options. The single switch structure of the proposed converter makes it suitable for implementing control algorithms. All the semiconductor devices (switch and diodes) of the proposed converter experience reduced voltage stress due to the adopted circuit architecture. The component rating and size is reduced considerably due to the reduced voltage stress of the semiconductor devices of this converter. This paper includes principle of operation, steady state analysis, design procedure, simulation results and experimental results of the proposed hybrid SI-SC (HSISC) converter. Results available from the hardware model of 380V/200W validate the performance of the converter at full load efficiency of 92.23%. All the analysis and results confirm the appropriateness of the converter for fuel cell based DC microgrid application.</p> Nilanjan Tewari Vaibhav Gurjar Sachhidanand Meenakshi J Sreedevi V T Copyright (c) 2021 Nilanjan Tewari, Vaibhav Gurjar, Sachhidanand, Meenakshi J, Sreedevi V T 2021-10-01 2021-10-01 1 01 "Electrochemical performance and fabrication of different Polyaniline (PANI) morphologies as supercapacitor electrodes ". https://spast.org/techrep/article/view/2883 <p>We develop and fabricate different morphologies of Polyaniline (PANI) viz., granular (Fig. 1a), <br>pebbles (Fig. 1b), spheres (Fig. 1c), tubes (Fig. 1d), fibres (Fig. 1e) and flakes (Fig.1f) via two <br>methods: chemical polymerization method and self-assembled method of polymerization of Aniline <br>monomer. The synthesis process is carried out in the presence of dopants, Hydrochloric Acid (HCl), <br>Ammonium persulfate (APS) as an oxidant and Triton X-100 as a surfactant to form PANI<br>morphologies. The as-synthesized PANI samples are characterized for surface morphology via Field <br>Emission Scanning Electron Microscopy (FE-SEM), electronic transition information within the <br>PANI chain network via UV-Vis spectroscopy, band and functional groups information via Fourier <br>Transform Infra-red spectroscopy (FTIR), phase structure, crystallinity, amorphous nature determined <br>via X-ray diffraction (XRD) and thermal stability via Thermogravimetric analysis (TGA). Raman <br>analysis reveals the amorphous nature of the PANI structures. All the results obtained from above <br>characterization techniques confirm the formation of the PANI fabrication. PANI is one of the most <br>important kind of conducting polymers that has been playing a tremendous role in the energy storage <br>devices. PANI has become a research corner for supercapacitor electrode material due to low cost of <br>aniline monomer, facile synthesis, environmental stability and high specific pseudocapacitance values <br>and it alone can be used in electrode materials [1]. It solves the problems related with specific <br>capacitance of pseudocapacitance but cycling performance is poor.<br>For fabrication of PANI electrodes, acetylene black is used as conducting agent and PVDF used as <br>binding material to form active materials. They are pasted onto the graphite sheet as a current <br>collector and tested as a supercapacitor electrodes performances in aqueous acidic electrolytes 0.1M<br>H2SO4 and gel polymer electrolytes (PVA/H2SO4) using Cyclic Voltammetry (CV), Galvanostatic <br>charge/discharge (GCD) and Electrochemical Impedance Spectroscopy (EIS) analysis. They evaluate <br>the sustainability of the PANI electrodes for supercapacitor application.<br>SPAST Abstracts Gyan Singh, Yogesh Kumar and Samina Husain, IGCSTS-1, 2021 <br>It is seen that as the aniline monomer concentration, temperature and time of stirring changes, the <br>electrochemical properties of the material changes significantly due to the different morphologies. It <br>is analysed that PANI with different morphologies having different specific capacitance are mainly <br>governed by the synthesis and its conditions. The fabricated electrode materials exhibits good specific <br>capacitance, rate performances, long cycle stability in polymer gel electrolytes PVA/H2SO4 instead of <br>the acidic electrolyte H2SO4. The development and fabrication of different morphologies based PANI<br>[2] as perspective electrode material enhances the electrochemical properties and provides a feasible <br>route for promoting the applications in supercapacitor for the future generation.</p> GYAN SINGH Copyright (c) 2021 GYAN SINGH 2021-10-19 2021-10-19 1 01 Modelling of power-optimized saturated SRAM design with high performance and low-power cardiovascular deceases https://spast.org/techrep/article/view/3059 <p>Throughout history, technology is evolving at a faster and more dynamic rate. Memory has been one of the primary modules that utilize ultralow-power technologies, leading to technological advancements which help humans satisfy their requirements. To fulfill rising demand, the device's size is shrinking [1-2], resulting in greater energy conservation. As a result, an SRAM cell with low power consumption [3] and adequate read and write stability is needed. The SRAM's basic structure [4] is based on pass transistors and a CMOS design. The research work proposed in the paper refers to Saturated NMOS inverter-based 8T SRAM [5]. The performance of the design is analyzed based on reading and writing operations. Functionality [6] is evaluated based on rising and fall time [7].&nbsp; Leakage, dynamic power [8] is characterized under sub threshold region operation by technological variations [9]. All the parameters are compared with the standard SRAM design [10].</p> Vasudeva Reddy T Copyright (c) 2021 Vasudeva Reddy T 2021-11-06 2021-11-06 1 01 The Production of Hydrogen by Biological Method from Crude Glycerol https://spast.org/techrep/article/view/1718 <p>Hydrogen (H<sub>2</sub>) is a clean, effective and renewable fuel which can be produced by different methods including biological ones, namely fermentation. To improve fermentative H<sub>2</sub> production the strategies, implicating use of by-products, utilization of carbon containing organic wastes and optimization of biotechnology process conditions, are developed. Glycerol, a biodiesel by product, can serve as a cheap carbon containing source to produce H<sub>2 </sub>by mesophilic bacteria.</p> <p>Unlike fossil fuels, Hydrogen contains no carbon and hence does not generate CO<sub>2</sub> emission at the point of use. This is unsustainable for the reason that using natural gas depletes fossil fuel resources and the process generates significant Greenhouse gas (GHG) emission. Biodiesel is one of those alternative fuels which have picked up keen interest of the people due to its similar properties to diesel. However due to Biodiesel being costlier than diesel in the present scenario, it has not been preferred to diesel. Biodiesel has become more competitive against petroleum diesel due to the higher prices of crude oil and increased demand for environmentally. However, if the cost of Biodiesel is reduced then its effective usage can be made, either by utilising its by product (Glycerol) effectively. Data on metabolic pathways and dependence of H<sub>2</sub> production on external factors during glycerol fermentation are summarized. Optimal conditions and analysis of gas sample are highlighted. All of these are significant for further development H<sub>2</sub> production from glycerol and perspective for applied energy systems.</p> <p>To overcome the challenge for the demand of clean energy, by utilizing waste resource through economical method.</p> Rakesh kumar TEJAS S MADANE POOJA C KALAMADI PRIYA S Kruthika M K Copyright (c) 2021 Rakesh kumar, TEJAS, POOJA, Mrs PRIYA S, Kruthika 2021-10-08 2021-10-08 1 01 Designing High-Performance Symmetric Supercapacitors from Waste Jute and Bio-electrolyte https://spast.org/techrep/article/view/1792 <p>Electronic technologies, particularly cell phones to electronic cars, have been essential in our everyday needs. However, the consequences of the energy demand at a high rate to power up these devices severely affect our biodiversity.&nbsp; We need to design highly efficient, clean, and renewable energy storage systems to address these issues. Supercapacitors are one option for clean and renewable energy devices, minimizing the gap between batteries and traditional capacitors. The potential demand for supercapacitors is growing in hybrid electrical devices [1]. Attempts have been made on enhancing the energy-storage capability of electric double layer (EDL) based supercapacitors while maintaining a high-power density. The biomass-derived carbonaceous materials are promising in performance compared to the conventional graphene-based materials (GO, rGO), single-wall carbon nanotube (SWCNT), or multiwall carbon nanotube (MWCNT), etc. for their specific morphological features [2]. Generally, the features include the large surface area, highly porous nanostructures with large pore volume [2]. Additionally, the biomass-derived carbonaceous material offers waste mitigation issues in environmentally-friendly forms. However, the synthesis of carbonaceous materials from biomass <em>via</em> chemical or physical carbonization for supercapacitor anode electrodes seems especially attractive but suffers from lower yield and cost issues. Besides, the carbonization process requires massive sophistication, especially the precursors' pre-treatments, carbonization temperatures, exposure time, activating agents, and gas flow during the pyrolysis process [3, 4]. Instead, the hydrothermal process to convert biomass precursors into carbonaceous material is expected to be feasible than the conventional carbonization process. The hydrothermal process usually deals with convenient reaction conditions like- lower temperature, lesser precursor treatments, and facile incorporation pathway to dope other materials into the biomass precursor [5].</p> <p>Now, as all the biomass precursors are structurally and morphologically different, without performing proper electrochemical experiments, there are no other practical methods to predict the electrode material's performance prepared from such resources. As a result, the electrochemical performance of supercapacitors from various biomass materials has been studied, including rice husk, sugar cane bagasse, potato starch, bamboo, eggshell membranes, etc. [6–8]. Similarly, jute is an agricultural by-product, and the abundance of cellulose and hemicellulose contents makes jute a prospective source to obtain electrode material for supercapacitor applications [9]. In this work, waste jute fiber is hydrothermally treated into a stainless-steel autoclave at 220<sup>o</sup>C for 24 h to get nano-carbon electrodes for supercapacitor application. The pre-treated jute fiber evolves reactive gases at this high temperature, and pressure in the closed tube allows the introduction of various porosity into the carbonaceous material. Camila Zequine group chemically activated (KOH as activating agent) jute fiber to fabricate a carbon-based supercapacitor. They have found a specific capacitance of 185 Fg<sup>-1</sup> at 500 mAg<sup>-1</sup> and at an energy density of 21 Whkg<sup>-1</sup> in a standard three-electrode system using 3M KOH electrolyte [8]. Most of the early works reported low specific capacitance, short cycle life, and lower energy density.</p> <p>However, the fundamental trick to increasing the electrochemical potential window thus energy density is selecting appropriate electrolytes. Different electrolytes have been reported to design supercapacitors, including aqueous, organic, ionic liquid, and polymer-gel electrolytes. Though aqueous electrolytes are the most widely used, conventional aqueous electrolytes have limited potential windows and biocompatibility [10–12]. In this context, bio-electrolytes could open captivating prospects to encourage future generation modern electrolytes. Compared with conventional aqueous electrolytes, bio-electrolytes like sodium acetate show attractive benefits, such as higher energy density, biocompatibility, biodegradability, and lower cost [13]. They are living organism-generated biomolecules and also waste materials of various industries like medical and pharmaceuticals. It has compelled to bias research and development for harnessing clean energy and storage systems. Hence by limiting the O<sub>2</sub>/H<sub>2</sub> evaluation, the sodium acetate electrolyte can broaden the thermodynamic stability of water. Generally, the acid equilibrium of water and the hydrogen bond between the hydrogen molecule to its nearest oxygen molecule in the water are the two significant factors responsible for water decomposition [10]. Since sodium acetate is very soluble in water, strong hydration of Na<sup>+ </sup>and C<sub>2</sub>H<sub>3</sub>O<sub>2</sub><sup>- </sup>with water may lower the free water content attached to H<sup>+</sup> to form H<sub>3</sub>O<sup>+</sup> ions. Moreover, lowering the hydrogen bond causes a strong O-H bond which results in a wide potential window [14]. To better understand the mechanism of how sodium acetate expands the potential window, one should consider the electrode-electrolyte interaction. The hydrothermally treated carbon contains hydrophilic surface groups (OH-, COO-, C-O-C, etc.), therefore, the sodium acetate molecules are absorbed on the carbon surface with their hydrophilic groups [9]. It results in an increase in the energy barrier of 1.3 eV for water molecules, where the energy barrier for Na<sup>+ </sup>of sodium acetate electrolyte to be absorbed in the carbon surface is lowered to 0.406 eV [10].&nbsp; This lower electronic barrier for sodium acetate demonstrates that it is facile for Na<sup>+</sup> to go to the carbon surface faster than water molecules. Thus, using aqueous sodium acetate electrolytes, the electrochemical window and specific capacitance of carbon-based supercapacitors are expected to be enhanced. Therefore, they have the potential to be used in supercapacitor devices as bio-electrolytes for ensuring a clean and sustainable environment. A Schematic illustration to the way of fabricating supercapacitor with waste jute carbon electrode with sodium acetate is shown in fig. 1.</p> Ragib Shakil Yeasin Arafat Tarek Akter Hossain Reaz Chanchal Kumar Roy Al-Nakib Chowdhury Copyright (c) 2021 Ragib Shakil, Yeasin Arafat Tarek, Akter Hossain Reaz, Chanchal Kumar Roy, Al-Nakib Chowdhury 2021-10-09 2021-10-09 1 01 Effect of electrolyte on the performance of supercapacitors https://spast.org/techrep/article/view/407 <p>The significant increase in global economy and urbanization results in accelerated depletion of fossil fuel reserves as well as some serious environmental problems such as increased greenhouse gas emission, pollution etc. Thus, a paramount importance has been given to the development of zero-emission renewable energy technologies. In this regard, electrochemical energy storage devices such as supercapacitors [1-3] and batteries [4, 5] gain great research interest owing to their good efficiency, high stability, as well as non-toxic nature. However, the electrochemical supercapacitors are a preferred choice for applications that demands high power (electric vehicles, satellites, robots etc), rapid charging/discharging ability as well as long cycle life in comparison to batteries. For high performance of electrochemical supercapacitors, electrolytes play a very imperative role. A large variety of electrolytes, such as aqueous electrolytes, organic electrolytes, ionic liquids electrolytes, redox-type electrolytes and solid or semi-solid electrolytes have been investigated. In all electrochemical processes, the interaction among electrodes and electrolyte considerably influence the electrode-electrolyte interface state as well as the internal structure of active material. For instance, the matching between the electrolyte ion size and the pore size of carbon based electrode has a significant effect on the obtained specific capacitance. The pseudocapacitances from the carbon-based electrodes and transition metal oxides are also highly dependent on the type of electrolytes used [6, 7]. Moreover, the viscosity, boiling point and freezing point of the electrolytes highly influences the thermal stability as well as the operating temperature range of the electrochemical supercapacitors. It has also been observed that the aging and breakdown of electrochemical supercapacitor are also due to the electrochemical decomposition of the electrolyte used which may be due to the incompatibility of the electrolyte with the supercapacitor electrode material. Generally, the requirements for an ideal electrolyte includes a broad potential range, high ionic conductivity, good stability,&nbsp; wide operating temperature, highly compatible with the electrode material, non-volatility and low flammability, non-toxic as well as cost effective. Till now, there has been no single electrolyte that completely fulfils all the requirements of electrochemical supercapacitor device. For example, supercapacitor using aqueous electrolytes exhibits high conductivity as well as high specific capacitance but low energy density and poor cyclic stability. Organic electrolytes and ionic liquids usually have lower ionic conductivity. Solid-state electrolytes may shun the potential leakage problem of the liquid electrolytes, but they also exhibit low ionic conductivity. Therefore, the performance of the electrode material and hence the supercapacitor device depends highly on the selection of the electrolyte. As a result, the development of highly compatible electrolytes is very crucial for developing safe and high performance supercapacitors.</p> <p>This article reviews the progress in the electrolytes for electrochemical supercapacitors. The effects of electrolyte properties on the electrochemical performance of supercapacitors are also discussed along with the interaction among the electrolyte, electro-active material and inactive component (current collectors, binders, and separators). Various important challenges encountered along with their potential solutions for developing highly efficient electrolytes are also scrutinized.</p> Sonali Verma Copyright (c) 2021 Sonali Verma 2021-09-15 2021-09-15 1 01 Influence of Vanadate Structure on Electrochemical Surface Reconstruction and OER Performance of CoV2O6 and Co3V2O8 https://spast.org/techrep/article/view/633 <p>The increase in global population and modernization of the world created a surge in the energy demand. Currently, carbon-based fossil fuels like coal, petroleum, natural gases etc., are the most widely used energy sources. However, they are limited in resources, and the burning of these fuels produces greenhouse gases which create a harmful impact on the environment. Wind, solar, geothermal energies are considered efficient, clean energy sources, but their intermittent nature restricts their real-life applications [1]. In this regard, Hydrogen is increasingly envisaged as an alternative fuel due to its highest gravimetric energy density (142 MJ/kg) and environmentally benign nature. Electro-catalytic water splitting is a promising method to produce hydrogen in a sustainable manner. For efficient water splitting, the oxygen evolution reaction (OER) at the anode acts as a bottleneck due to its four-electron/proton-coupled mechanism. To facilitate OER, catalysts are generally employed, but most are based on expensive metals, such as Ir, Rh etc. This has enthused researchers to develop cheaper transition metal based catalysts. Although many transition metal based catalysts have been developed, cobalt vanadate systems as OER catalysts are less explored [2]. This enthused us to synthesize pure phase Co<sub>3</sub>V<sub>2</sub>O<sub>8</sub> and CoV<sub>2</sub>O<sub>6</sub> by thermal co-precipitation followed by calcination. We could able to get these two different phases of cobalt vanadate by altering the reaction conditions slightly. Among these materials, CoV<sub>2</sub>O<sub>6</sub> showed higher geometric electrocatalyst activity towards OER. The overpotential requirement to attain the benchmark current density of 10 mA/cm<sup>2</sup><sub>geo</sub> was 360 mV, whereas Co<sub>3</sub>V<sub>2</sub>O<sub>8</sub> required 510 mV overpotential to reach 10 mA/cm<sup>2</sup><sub>geo</sub> current density.</p> <p>In addition, we have investigated the factors responsible for the superior phase-dependent electrocatalytic OER activity of two different crystalline cobalt vanadate phases. Vanadates as a class of oxometallates can exist as discrete as well as polymeric ions. For example, while orthovanadate is a discrete [VO<sub>4</sub>]<sup>3−</sup> ion, metavanadate ([VO<sub>3</sub>]<sub>n</sub>)<sup>n−</sup> can be visualized as a polymeric network of VO<sub>3</sub> units.&nbsp; Earlier reports on cobalt vanadate as OER catalyst have ascribed activity difference to optimal metal-oxygen bond strength. In contrast, we found out that the etching of vanadate moieties from the precatalyst during the electrochemical activation plays a pivotal role [3].</p> <p>Further, we observed that the polymerization of vanadate ions significantly affects the etching process. CoV<sub>2</sub>O<sub>6</sub> has a polymeric structure consisting of chains of [VO<sub>3</sub>]<sup>−</sup>, formed via corner-shared VO<sub>4</sub> tetrahedra, corner-shared VO<sub>6</sub> octahedra, and edge-shared VO<sub>6</sub> octahedra, whereas in Co<sub>3</sub>V<sub>2</sub>O<sub>8</sub> vanadate ions only exist as discrete [VO<sub>4</sub>]<sup>3-</sup> tetrahedral. Due to the polymeric structure of metavanadate, its etching from the material would tear off a long chain of vanadate, thereby aiding the transformation of the material to its active phase. In contrast, the etching of orthovanadate is structurally constrained and, thus, much slower in nature. The resulting higher surface reconstruction exposes a higher number of catalytically active cobalt sites that otherwise lay inactive due to their position in bulk. Cobalt vanadates with polymeric vanadates (CoV<sub>2</sub>O<sub>6</sub>) showed better OER over monomeric orthovanadates (Co<sub>3</sub>V<sub>2</sub>O<sub>8</sub>) due to higher vanadate etching. Further, this work validates that etching can happen even from lattice positions, where bonding between constituents are strong.</p> Ayan Mondal Sagar Ganguli Harish Reddy Inta Venkataramanan Mahalingam Copyright (c) 2021 Ayan Mondal, Sagar Ganguli, Harish Reddy Inta, Venkataramanan Mahalingam 2021-09-19 2021-09-19 1 01 PbTe and PbSe based Thermoelectric Materials : A review https://spast.org/techrep/article/view/806 <p>To meet the increasing power demand researchers have been working for different methods of energy conversion. One of the best method for waste heat recovery is the use of thermoelectric materials. Thermoelectric materials can convert heat into electrical energy. The current area of interest is to explore highly efficient thermoelectric materials at room temperature. PbTe based alloys, Bi<sub>2</sub>Te<sub>3</sub> based alloys and SiGe alloys are some of the traditional thermoelectric materials. PbTe is an excellent thermoelectric material around mid temperature range. Due to its simple crystal structure and narrow band gap of 0.33 eV PbTe is widely used in thermoelectric applications (1,2). Selenium is more abundant than Te. PbSe is referred to as sister material of PbTe. Other advantages of PbSe is its high melting point, low cost, narrow band gap (~0.28 eV), low thermal conductivity (~1.6 W/m K) and higher operating temperature (3). A systematic study of PbTe and PbSe doped with different materials as a function of temperature and carrier density has been reviewed. Nanostructuring, alloying and band engineering are some of the strategies used to enhance the thermoelectric performance of materials (2) . This paper reports the need of third element introduced in the parent material PbTe and PbSe to enhance the thermoelectric properties (4,5).</p> Isha Sihmar Copyright (c) 2021 Isha Sihmar 2021-09-18 2021-09-18 1 01 Design and Implementation of a PV Solar System for regular Non-Commercial Use https://spast.org/techrep/article/view/843 <p>Solar energy being renewable and abundant is truly a green energy solution in times when the world is on the verge of exhausting all non renewable energy resources. However as the study on utilisation of solar energy is still ongoing, it’s utility in day to day life despite of being easy isn’t wide spread. Hence it becomes important to set up small systems and analyse the overall impact and then slowly shift the electrical system from the conventional form to this eco-friendly solution. This project is an endeavour of designing a solar based electrical circuit which is capable of running daily appliances. Analysing the electrical parameters of the solar cells and thus setting up a circuit with optimum productivity is focused. Standard Test Conditions are taken into account before installing the panels. Post installation the intensity of light falling on the panel at different times is recorded and the corresponding power is measured. The IV characteristics of the panel is plotted against time and the best time to store current is determined. The design of the circuit is the most crucial and influential part and hence is drawn with utmost details of the loads to be connected and the output to be gained. While installing the panels the latitude of the region is taken into consideration to keep the panels perpendicular to the sun at noon when the intensity peak is the highest. The advantages and disadvantages of different types of PV cells is studied and points of disadvantage of the module used is studied further to improve the overall efficiency. The gain of series and parallel connections is compared and accordingly the design is drawn. Taking into account the electric load requirement, load analysis is done ensuring efficient use of the natural energy alongside not hampering any device. Thus Load estimation, Solar array sizing, Battery Bank sizing, Inverter sizing, Solar charge controller sizing are the major points focused in laying out the PV system. Also throughout the process, safety and security aspects are taken into consideration and accordingly are implemented. Once this prototype shows optimum productivity and profitability it can be enlarged and installed on a larger scale thus moving on the path of shifting from non renewable energy to renewable solar energy. This shall eventually give rise to new fields of study and broaden the electrical sector along with going a step further in protecting the environment. Depletion of recourses, pollution, global warming are the issue which shall be sufficiently tackled with this green energy solution. [1] Thus solar energy is sustainable and is the need of the hour. Especially is running of day to day appliances, solar power is the best resource – specifically in a tropical country like India. Though at present solar is best for DC current and an external inverter is required for AC appliances making the circuit costlier; but if the concept is given greater exposure and utilized on a large scale the disadvantage of cost would gradually strike out. Thus solar energy is a green energy alternative with great potentials and practical implementation.</p> Tulika Sinha Abhida Nadar Adesh Dalvi Deepak Singh Shalini Swami Copyright (c) 2021 Tulika Sinha, Abhida Nadar, Adesh Dalvi, Deepak Singh, Shalini Swami 2021-09-16 2021-09-16 1 01 Influence of Binder in the Fabrication of AC-based High Performance Electrochemical Supercapacitor https://spast.org/techrep/article/view/1651 <p style="text-align: justify;"><span style="font-size: 11.0pt; font-family: 'Arial',sans-serif;">In modern society, the potential demand for energy is rising due to rapid population growth and socioeconomic advancement. In order to supply this huge amount of energy, various renewable technologies like solar, wind, tidal, biogas, and nuclear technology have already been developed. Producing clean and renewable energy is not the only challenge, rather storing the energy has also appeared a major concern. As a result, electrochemical energy storage devices like supercapacitors have become an important topic of study [1]. As a novel energy storage technology, electrical double-layer capacitors (EDLCs) employ novel carbon as the electrode material and may supply high power in a short period while maintaining an outstanding cycle [2]. This is due to the well-tuned hierarchical porous structure, high specific surface area, superior electrical conductivity, and good chemical and thermal stability, biomass-derived activated carbon (AC) has attracted tremendous attention for its potential applications as an electrode material or electrode modifier in supercapacitor technologies [3-5].</span></p> <p style="text-align: justify;"><span style="font-size: 11.0pt; font-family: 'Arial',sans-serif;">However, AC-based-supercapacitor electrodes are often made by spraying or coating an electrode paste or slurry of AC on a current collector such as graphite, aluminum foil, nickel foam, etc. In this work, a combination of AC, conductive agents, and binders (cohesive agent) is ultrasonically mixed to create the electrode paste or slurry. The binders bind active materials from falling off and give enough strength during electrochemical operation. Interestingly, the binders, on the other hand, invariably cover certain surface regions or pores of active molecules. As a result, the characteristics of binders and their contents in electrodes will have a direct impact on the electrochemical performance of supercapacitors. Thus, it is critical to understand how to select a good binder [6].</span></p> <p style="text-align: justify;"><span style="font-size: 11.0pt; font-family: 'Arial',sans-serif;">Among others, the chemical structures of carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and polyvinylidene fluoride (PVDF) are shown in Fig. 1(A), which are favorable for AC- based supercapacitors. The CMC possesses lower mechanical stability and it could not be utilized beyond 40 with any water or oxygen but demonstrated a reduced resistivity. Whereas PVDF is made up of a CH<sub>2</sub>-CF<sub>2</sub> unit, it possesses conventional fluoropolymer stability, but interacting groups create a unique polarity, resulting in a better chemical and oxidative resistance, low wettability, and considerable swelling in the electrolyte.</span></p> <p style="text-align: justify;"><span style="font-size: 11.0pt; font-family: 'Arial',sans-serif;">In this study, we have investigated the interaction of a highly porous activated carbon with different polymeric binders (CMC, PVP, and PVDF) and tested its applicability as AC-based supercapacitor electrodes. The AC was synthesized from banana leaves followed by carbonization under Ar flow at 750&nbsp;with an activating agent (K<sub>2</sub>CO<sub>3</sub>). The total synthesis route is shown in Fig. 1(B). The presence of different types of functional groups was confirmed by analyzing the Fourier Transform Infrared Spectroscopy (FTIR) spectrum. The morphology of the as-prepared AC was investigated by using a Field Emission Scanning Electron Microscope (FESEM), X-Ray Diffraction (XRD), and Ramon spectroscopy.</span></p> <p style="text-align: justify;"><span style="font-size: 11.0pt; font-family: 'Arial',sans-serif;">The supercapacitor performance of the AC was evaluated in a standard 3-electrode setup containing NaSO<sub>4</sub> as electrolyte by performing cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS), and cyclic stability tests. In fabricating the supercapacitor, the modified graphite electrode was used as the working electrode, Ag/AgCl, and platinum wire was used as the reference and counter electrode, respectively. To examine the effect of the binder on the supercapacitor’s performance, three different kinds of binders were employed in fabricating the AC- modified graphite electrode of the supercapacitor. The highly porous AC with PVDF binder shows the best current response as well. The highest specific capacitance of 255 Fg<sup>-1</sup> is found at 0.5 Ag<sup>-1</sup> in the potential window of 1.4 V. The overall performance of AC with different binder materials is shown in Table 1. It is expected that the present work will significantly contribute to constructing an AC-based supercapacitor with the proper selection of polymeric binder materials for high efficiency.</span></p> Md. Moniruzzaman Anwarul Azim Akib Ragib Shakil Chanchal Kumar Roy Al-Nakib Chowdhury Copyright (c) 2021 Md. Moniruzzaman, Anwarul Azim Akib, Ragib Shakil, Chanchal Kumar Roy, Al-Nakib Chowdhury 2021-10-08 2021-10-08 1 01 Numerical Simulation for Cd-free Sb2S3 based Photovoltaics https://spast.org/techrep/article/view/1693 <p>Solar energy harnessing can meet energy demand of the world and can solve the problem like global warming caused by traditional source fossil fuel. Photovoltaic technologies including wafer, thin film, and organic solar cell have been developed to convert solar energy into electricity. Among them, thin film technology needs very less material to fabricate the solar cell which makes thin film solar cell cost effective and more available in the market. CIGS (Copper Indium Gallium Selenide) and CdTe (Cadmium Telluride) based solar cells are commercially available thin film solar cells since it has got efficiency comparable to silicon wafer solar cells. But due to the scarcity of the constituent elements like In, Ga and toxicity of Cd hinder further development. CZTS (Copper Zinc Tin Sulfide) solar cell made of earth abundant material was believed to overcome scarcity and toxicity issue but the associated secondary phases result in low efficiency [1].</p> <p>On searching alternative material for thin film technology, antimony sulfide Sb<sub>2</sub>S<sub>3</sub> deserves special attention due to its suitable optoelectronic properties including band gap (1.7eV) and high absorption coefficient ( &gt; 10<sup>4</sup> cm<sup>-1</sup>), stable phase, and non-toxicity [2]. Recently, Sb<sub>2</sub>S<sub>3</sub> is being widely studied for its photovoltaic property and has emerged as a suitable alternate to the quaternary CIGS and CZTS based photovoltaics (PV). Despite numerous research work focused on antimony sulfide, its power conversion efficiency is still low and is limited to ~7% [3]. The low efficiency can be attributed to quick recombination of electron and hole due to the presence of mid-gap as well as interfacial defects. Another major challenge in Sb<sub>2</sub>S<sub>3</sub> based PV is the band offset between the absorber and the buffer layers. Conduction band offset (CBO) strongly influences the photoconversion efficiency [4]. CdS is the conventional buffer layer in CIGS and CZTS photovoltaic cells and the same also has been reported widely for Sb<sub>2</sub>S<sub>3</sub>. The CBO for Sb<sub>2</sub>S<sub>3</sub>/CdS heterojunction is nominal with a spike of ~0.37 eV. But, the usage of cadmium is not environment friendly for both producer and consumer. Further, the narrow band gap of CdS causes absorption at shorter wavelength region and reduces the overall efficiency [5]. Keeping this we propose a suitable alternative ternary buffer layer Zn(O,S) for Sb<sub>2</sub>S<sub>3</sub> PV cell for which the CBO can be tuned by varying the S concentration.</p> <p>In the present work, Sb<sub>2</sub>S<sub>3</sub> PV cell with Zn(O,S) buffer layer has been numerically analyzed using SCAPS 1D [6] simulator. SCAPS 1D calculates solar cell parameter using Poisson’s equation and continuity equation for hole and electron. Simulation has been carried out for the solar cell configuration ITO/Zn(O,S)/Sb<sub>2</sub>S<sub>3</sub>/Ni. Zn(O,S) has been used as buffer layer to overcome the issue connected with&nbsp; traditional CdS buffer. The electron affinity of Zn(O,S) can be tuned by varying the S content which in turn enables the tuning of CBO. The simulation is performed in two stages. Firstly, absorber layer thickness, buffer layer thickness, carrier concentration, defect density and interface defect density are optimized. The electron affinity of buffer layer is optimized to optimize the CBO between the absorber and the buffer layers. Secondly, under optimized condition, the solar cell ITO/Zn(O,S)/Sb<sub>2</sub>S<sub>3</sub>/Ni is simulated. The solar cell parameter such as open circuit voltage (V<sub>oc</sub>), short circuit current density (J<sub>sc</sub>), fill factor (FF) and power conversion efficiency have been obtained under global AM 1.5 conditions. The main objectives of the present work are to find the optimal layers parameters for achieving better efficiency and to replace the toxic CdS with Zn(O,S). This work will serve the experimentalist to overcome difficulties associates with Sb<sub>2</sub>S<sub>3</sub> solar cell and it will also provide a direction to improve efficiency of the solar cell. Figure 1 shows the proposed structure of the solar cell and Figure 2 shows the J-V characteristic result of the SCAPS for the structure. Device layer parameters used for simulation have been mentioned in Table 1.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <img src="https://spast.org/public/site/images/afzal/mceclip2.png"></p> <p>&nbsp;</p> <p>Fig.1. Proposed solar cell structure&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Fig.2. Initial J-V characteristic result</p> <p>Table 1: Layer parameters for Sb<sub>2</sub>S<sub>3</sub>/Zn(O,S) solar cell simulation using SCAPS-1D</p> <table width="729"> <tbody> <tr> <td width="255"> <p><strong>Material Parameters</strong></p> </td> <td width="160"> <p><strong>FTO </strong></p> </td> <td width="157"> <p><strong>Zn(O,S)</strong></p> </td> <td width="157"> <p><strong>Sb<sub>2</sub>S<sub>3</sub></strong></p> </td> </tr> <tr> <td width="255"> <p>Thickness (mm)</p> </td> <td width="160"> <p>0.5</p> </td> <td width="157"> <p>0.1</p> </td> <td width="157"> <p>1</p> </td> </tr> <tr> <td width="255"> <p>Bandgap (eV)</p> </td> <td width="160"> <p>3.5</p> </td> <td width="157"> <p>2.83</p> </td> <td width="157"> <p>1.7</p> </td> </tr> <tr> <td width="255"> <p>Electron Affinity (eV)</p> </td> <td width="160"> <p>4</p> </td> <td width="157"> <p>3.6</p> </td> <td width="157"> <p>3.7</p> </td> </tr> <tr> <td width="255"> <p>Dielectric Permittivity</p> </td> <td width="160"> <p>9</p> </td> <td width="157"> <p>9</p> </td> <td width="157"> <p>7.08</p> </td> </tr> <tr> <td width="255"> <p>CB Effective Density of State (1/cm<sup>3</sup>)</p> </td> <td width="160"> <p>2.2 x 10<sup>18</sup></p> </td> <td width="157"> <p>2.2 x 10<sup>18</sup></p> </td> <td width="157"> <p>2.2 x 10<sup>19</sup></p> </td> </tr> <tr> <td width="255"> <p>VB Effective Density of State (1/cm<sup>3</sup>)</p> </td> <td width="160"> <p>1.8 x 10<sup>19</sup></p> </td> <td width="157"> <p>1.8 x 10<sup>19</sup></p> </td> <td width="157"> <p>1 x 10<sup>19</sup></p> </td> </tr> <tr> <td width="255"> <p>Electron Thermal Velocity (cm/s)</p> </td> <td width="160"> <p>10<sup>7</sup></p> </td> <td width="157"> <p>10<sup>7</sup></p> </td> <td width="157"> <p>10<sup>7</sup></p> </td> </tr> <tr> <td width="255"> <p>Hole Thermal Velocity (cm/s)</p> </td> <td width="160"> <p>10<sup>7</sup></p> </td> <td width="157"> <p>10<sup>7</sup></p> </td> <td width="157"> <p>10<sup>7</sup></p> </td> </tr> <tr> <td width="255"> <p>Electron Mobility (cm<sup>2</sup>/V.s)</p> </td> <td width="160"> <p>20</p> </td> <td width="157"> <p>100</p> </td> <td width="157"> <p>20</p> </td> </tr> <tr> <td width="255"> <p>Hole Mobility (cm<sup>2</sup>/V.s)</p> </td> <td width="160"> <p>10</p> </td> <td width="157"> <p>25</p> </td> <td width="157"> <p>10</p> </td> </tr> <tr> <td width="255"> <p>Donor Density (N<sub>D</sub>) (cm<sup>-3</sup>)</p> </td> <td width="160"> <p>10<sup>20</sup></p> </td> <td width="157"> <p>2 x 10<sup>16</sup></p> </td> <td width="157"> <p>0</p> </td> </tr> <tr> <td width="255"> <p>Acceptor Density (N<sub>A</sub>) (cm<sup>‑3</sup>)</p> </td> <td width="160"> <p>0</p> </td> <td width="157"> <p>0</p> </td> <td width="157"> <p>5.5 x 10<sup>15</sup></p> </td> </tr> </tbody> </table> AFZAL BASHA M.I Z.C. Alex S.R. Meher Copyright (c) 2021 AFZAL BASHA M.I, Z.C. Alex, S.R. Meher 2021-10-08 2021-10-08 1 01 Consideration of chemically synthesized ZnO@WO3 nanoparticles as electron and hole transport layer in organic solar cells https://spast.org/techrep/article/view/687 <p>Metal oxides are a diverse class of inexpensive, non-hazardous, easily synthesized, and abundant materials utilised in a wide range of applications such as solar cells, photocatalysis, photodetectors, water splitting, and so on[1]. Because of their remarkable optical and electrical properties, inorganic semiconductors that utilise transition metal oxide nanoparticles such as WO<sub>3</sub> and ZnO have piqued the interest of researchers. ZnO is an n-type semiconductor with a direct bandgap of 3.37 eV [2]. It is regarded as a versatile material since it has highly developed fabricationtechniques and is relatively straightforward to prepare in nanostructure form [3]. These promising properties make ZnO an appealing foundation for the construction of different devices. On the other hand, WO<sub>3</sub> is a reliable semiconductor with a small bandgap (2.7–3.1 eV) [4]. Because of its unusual physicochemical features, it has the potential to be used in a wide range of technological applications, including semiconductor gas devices, gas sensors, solar energy devices, electrical devices, photocatalysts, optical storage devices, and emission devices. Core-shell nanomaterials have recently piqued the interest of researchers due to their wide range of potential applications when compared to individual components [5]. The coating or shell formation of WO<sub>3</sub> on ZnO nanoparticles opens up new possibilities for use in optoelectronic devices. Global environmental concerns and an increasing need for energy, together with ongoing advancements in renewable energy technologies, are creating new prospects for the usage of renewable energy resources around the world. Photovoltaic energy is an appealing option to other renewable energy sources for satisfying a variety of energy needs. Solar energy is the most abundant, inexhaustible, and environmentally friendly of all of the renewable energy sources available to us today.Current research is centred on developing photovoltaics that are both inexpensive and competent. Silicon-based photovoltaics have been claimed to be highly efficient, but as they are made of expensive materials and require a huge surface area, they are still unsuitable and even have insufficient functionality in the absence of sunlight. As a result, inorganic semiconductors with wide optoelectronic capabilities for photovoltaics, such as transition metal oxide nanoparticles, can be employed to avoid the instability of other organic solar cells (OSC) [6].</p> <p>In this study, ZnO@WO<sub>3</sub>nanoparticleshave been synthesized via sol-gel method. Sol-gel technique is the simplest technique and has the capability to control the particle size and morphology through systematic monitoring of reaction parameters. Various characterization techniques have been utilized for studying morphological, structural, and optical properties of the synthesized nanoparticles. Two different inverted OSCs were fabricated using the solution-processed ZnO@WO<sub>3</sub> nanoparticles as electron transporting layer (ETL) and as hole transporting layer (HTL) and the solar cell characteristics were examined. The first solar cell (device A) employing ZnO@WO<sub>3</sub> as ETL was fabricated with structure ITO/ZnO/ZnO@WO<sub>3</sub>/PTB7-Th:PC71BM/MoO<sub>3</sub>/Ag while the other solar cell (device B) employing ZnO@WO<sub>3</sub> as HTL was fabricated with structure ITO/ZnO/PTB7-Th:PC71BM/ZnO@WO<sub>3</sub>/MoO<sub>3</sub>/Ag. In comparison with the device A with ZnO@WO<sub>3</sub> as ETL, a notableimprovement is seen in device B with ZnO@WO<sub>3</sub> as HTL. An efficiency of 1.88% is observed in device B in comparison to the efficiency of 0.64% in device A. Our results suggest that ZnO@WO<sub>3</sub> nanoparticles have great potential in photovoltaics field.</p> Prerna Copyright (c) 2021 Prerna 2021-09-16 2021-09-16 1 01 The Effect of boron doping to enhance the specific capacity of Li3V2(PO4)3 and Li de-intercalation possibility https://spast.org/techrep/article/view/177 <p>Among different categories of cathode material phosphate or polyanion compound attracted worldwide interest due to high operating voltage, thermodynamical stability, and good specific capacity. Among several polyanion compounds Li<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> has the potential to be next-generation cathode material due to high operating voltage window 3.5 – 4.8 V, 133 mAh-gm-1, and 197 mAh-gm-1 specific capacity on two and three mol Li extraction, whereas LiFePO<sub>4 </sub>exhibit 163 mAh-gm<sup>-1</sup>. In our work, using first-principles calculation, we have demonstrated Boron (B) substitution can improve the specific capacity up to 205 mAh-gm<sup>-1</sup>. Whereas, in the case of pure Li<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>, we found Li<sub>1</sub> shows an unstable phase as compare to Li<sub>2</sub> and Li<sub>3</sub>. We have shown B substitution can improve the formation energy of Li<sub>1 </sub>atom as well electronic conductivity with bandgap reduce to 2.9 eV from 3.2 eV. This change in bandgap is all due to a change in the occupancy of the nearest O and V atom to B substitution.</p> Deepak Gavali Copyright (c) 2021 Deepak Gavali 2021-09-08 2021-09-08 1 01 Effect of solar radiation on the performance of solar air heater duct having dimple shape roughness on the absorber plate https://spast.org/techrep/article/view/926 <p>The artificial roughness on the heat transferring surface of a solar air heater brings about a considerable increment in heat transfer on the expense of increase in pressure drop. In the present study, the effect of intensity on heat transfer and friction factor coefficient has been investigated in a solar air heater duct with dimple shaped roughness ordered in angular fashion. The experimental set up exhibits the Reynolds number in the range of 3600-18000, while the range of intensity is 800-1200, relative roughness height (e/D<sub>h</sub>) 0.036, relative roughness pitch (p/e) 10 and angle of attack value of 60°.</p> Muneesh Sethi Copyright (c) 2021 Muneesh Sethi 2021-09-16 2021-09-16 1 01 Advances in MoS2 nanostructures and their composites: Synthesis characterization and hydrogen fuel generation https://spast.org/techrep/article/view/1123 <p>Global Hydrogen gas production market size is valued around 6 % (USD 119 billion) in 2020 and it is used as alternative fuel source to replace contemporary fuels like crude oil which are depleting at a faster rate and also direct threat to environmental health. Traditionally, platinum is used as a catalyst to accelerate the hydrogen evolution process. Although it shows excellent results, the high cost of platinum limits the use at laboratory level making it impractical in commercial applications. Molybdenum disulphide (MoS2) is a transition metal dichalcogenide which acts as catalyst in electro-chemical water splitting to produce hydrogen gas. This review aims to provide the various methods adopted for the synthesis of nanoscale MoS2 and its composites. Various methods such as hydrothermal, solvothermal, sol-gel, microwave, and their reaction conditions, reactant precursors adopted by different research groups were complied. The review was also focused on reveling the structural features of nanoscale MoS2 and its composites, from the results of XRD, SEM, EDS, PL Spectroscopy and Raman reported by various research works. The H2 generation efficiency of MoS2 and its composites were studied in an electro-chemical workstation to evaluate the catalyst performance. The photo/electrochemical studies on H2 generation by MoS2 carried out by various groups were studied and the results were discussed. The results were correlated in order to propose the suitable functionality, dopant, for better H2 generation performance of MoS2. Finally the review provides the summary of the various MoS2 nanocomposites, current challenges and future scope of H2 generation applications.</p> Abdul Rahman Faisal Shivaraj BW Manjunatha C Copyright (c) 2021 Abdul Rahman Faisal, Shivaraj BW, Manjunatha C 2021-09-21 2021-09-21 1 01 An Economic and Political Assessment on the Development of Green Hydrogen Infrastructure for Fuel Cell & IC Engine based Vehicles: From Indian Scenario https://spast.org/techrep/article/view/2745 <p>Hydrogen produced from fossil based fuels using various reformer techniques such as steam reforming usually operate at a low efficiency despite of using high cost fossil based fuels.&nbsp; Electrolysis of water is a critical technology for transition to the hydrogen economy since the method of hydrogen production would be a clean, domestic and carbon-free; moreover, the fuel (Water) is abundant by nature and henceforth hydrogen can be produced on-site whenever the situation demands. Electrolysers can thereby provide H<sub>2</sub> and/or O<sub>2</sub> for virtually any requirement. This paper deals with the comparative techno-economic assessment on hydrogen production by various conventional reformer techniques with respect to various electrolyzers. The comparison in this study is based on the purity of hydrogen produced, the efficiency of the system producing hydrogen, pros and cons of the various systems and the cost analysis for hydrogen production.&nbsp; The carbon-footprint of the generated H<sub>2 </sub>and O<sub>2 </sub>is principally a function of the input electricity. Thus, it is envisaged that future low-carbon economies will exploit electrolyzer technology to deliver ‘low/zero carbon hydrogen’ for fuel cells and other uses. The implication here is that electrolyzers may well be implemented and may soon supersede the conventional low energy efficient reformers.</p> <p>&nbsp;</p> <p>&nbsp;</p> Arunkumr Jayakumar Copyright (c) 2021 Arunkumr Jayakumar 2021-10-21 2021-10-21 1 01 Experimental Investigation of a Novel Design Solar Still Desalination System https://spast.org/techrep/article/view/1266 <p>Freshwater is the need of the hour. Water scarcity has created tensions, wars, and terrorism over the globe. Desalination of water from existing brackish and saline water bodies over the globe is the only probable solution that can mitigate the water demand of this thirsty society. Conventional desalination technologies consume enormous energy, thus demanding the penetration of renewable energy systems for a more innovative solution. Solar still-based thermal desalination systems are a sustainable approach to clean water production through clean energy [1].</p> <p>Various parameters affect the rate of evaporation as well as the rate of condensation of solar stills. Reviews made by researchers [2-5] indicates that the design and material of the solar still, the basin material’s heat capacity, evaporation surface area, feedwater temperature, temperature between basin water and condensing surface (glass lid inner surface), and many more factors influence the performance of the solar still. Amongst these challenges, the design and material have a significant impact on the performance and the economics of the solar still. In this paper, the glass cover design of solar still and the basin material are considered for an investigation to enhance the solar's productivity.</p> <p>The top cover is made to receive and transmit more solar radiation into the still and trap the thermal radiations reflected back to the atmosphere. The basin material has to collect the solar energy radiation transmitted into the still by the glass lid, convert the radiation into heat and simultaneously heat the water, provide maximum surface area for evaporation, and store excess thermal energy to utilize it when the radiation levels are low.</p> <p>Based on these considerations, a novel Twin Wedge shaped glass cover is designed with a basin made of Concrete material, which best fits the requirements. The glass material for cover is cost-effective and has high transmissivity. The Twin Wedge shape is symmetrical and straightforward in design with increased aperture area to receive more solar radiation and increased condensation surface area. The concrete basin material is economical, robust, non-corrosive, and stores sensible heat in order to enhance productivity during low or off-solar radiation duration. This solar still can be implemented in Green Buildings, where a water purification system can be integrated with the roof delivering higher yield and additional benefits.</p> <p>The main objectives of this paper are to compare the performance of the proposed solar still – Twin Wedge Solar Still (TWSS) with Conventional Solar Still (CSS) made of Mild Steel sheet metal and evaluate the economics of this system for futuristic development. The pictorial representation of the experimental setup is presented in fig. 1.A.The experiment was conducted for about 8 hours, and various temperature parameters are recorded for hourly intervals. The total collected water at the end of the day is measured for the total productivity during the daytime.</p> <p>Fig. 1.B shows the hourly variation of the ambient temperature, the difference in temperature between water and glass inner surface (T<sub>water</sub> - T<sub>glass,in</sub>), and the cumulative yield of both CSS and TWSS. The concrete basin behaved as a sensible heat storage medium throughout higher solar radiation hours and stored the thermal energy. The stored thermal energy is utilized during off-solar radiation hours to elevate the degree of heat of the water. The drop in ambient temperature ensures comparatively lower glass temperature, thus ensuring higher (T<sub>water</sub> - T<sub>glass,in</sub>) values (fig. 1.B). The cumulative yield curve shows that the TWSS delivered 1.3 liters per m<sup>2</sup> of distilled water over 8 hours, whereas the CSS delivered only half (0.635 liters per m<sup>2</sup>) of the TWSS productivity. The daily energy efficiency of the TWSS is 33.94%.</p> <p>The concrete basin TWSS has a longer lifetime than the CSS. The economic analysis [6] in table 1 showed that for a selling price of $ 0.3 per liter of distilled water, the payback period was only 11 months for TWSS whereas, it is five years and ten months for CSS. In high temperature areas, the TWSS can be integrated to buildings to harvest the solar radiation falling onto the roof generating heat. TWSS utilizes the heat to desalinate water simultaneously reducing the heat penertration into the building thus keeping the room temperature comparatively lower in simple and economic manner with higher yield than CSS.</p> <p><strong>Fig.1.</strong> Initial Experiments and results: A. experimental setup B. hourly variation of (T<sub>water</sub>-T<sub>glass,in</sub>) and Cumulative yield in both CSS and TWSS over the testing period.</p> <p><img src="https://spast.org/public/site/images/awjdason/fig-1.png" alt="Fig.1. Initial Experiments and results: A. experimental setup B. hourly variation of (Twater-Tglass,in) and Cumulative yield in both CSS and TWSS over the testing period." width="1117" height="429"></p> <p>Table 1. Economic Analysis and Payback period of the TWSS and CSS systems.</p> <table style="height: 868px;" width="923"> <tbody> <tr> <td width="197"> <p><strong>Parameters</strong></p> </td> <td width="126"> <p><strong>CSS</strong></p> </td> <td width="102"> <p><strong>TWSS</strong></p> </td> <td width="183"> <p><strong>Remarks</strong></p> </td> </tr> <tr> <td width="197"> <p>Yield per day (m)</p> </td> <td width="126"> <p>0.635 liters per m<sup>2</sup></p> </td> <td width="102"> <p>1.3 liters per m<sup>2</sup></p> </td> <td width="183"> <p>&nbsp;</p> </td> </tr> <tr> <td width="197"> <p>Annual Yield (M)</p> </td> <td width="126"> <p>190.5</p> </td> <td width="102"> <p>390</p> </td> <td width="183"> <p>m x 300 solar days</p> </td> </tr> <tr> <td width="197"> <p>Capital Cost (C)</p> </td> <td width="126"> <p>&nbsp;$&nbsp;&nbsp;&nbsp; 230.00</p> </td> <td width="102"> <p>&nbsp;$&nbsp;&nbsp;&nbsp;&nbsp; 95.00</p> </td> <td width="183"> <p>&nbsp;</p> </td> </tr> <tr> <td width="197"> <p>interest per year (i)</p> </td> <td width="126"> <p>12%</p> </td> <td width="102"> <p>12%</p> </td> <td width="183"> <p>&nbsp;</p> </td> </tr> <tr> <td width="197"> <p>Life span (n)</p> </td> <td width="126"> <p>10 years</p> </td> <td width="102"> <p>25 years</p> </td> <td width="183"> <p>&nbsp;</p> </td> </tr> <tr> <td width="197"> <p>Capital Recovery Factor (CRF)</p> </td> <td width="126"> <p>0.177</p> </td> <td width="102"> <p>0.127</p> </td> <td width="183"> <p>i(1+i)n/[(1+i)n-1]</p> </td> </tr> <tr> <td width="197"> <p>Fixed Annucal Cost (FAC)</p> </td> <td width="126"> <p>&nbsp;$&nbsp;&nbsp;&nbsp;&nbsp; 40.71</p> </td> <td width="102"> <p>&nbsp;$&nbsp;&nbsp;&nbsp;&nbsp; 12.11</p> </td> <td width="183"> <p>C x (CRF)</p> </td> </tr> <tr> <td width="197"> <p>Sink Fund Factor (SFF)</p> </td> <td width="126"> <p>0.475</p> </td> <td width="102"> <p>0.062</p> </td> <td width="183"> <p>1/[(1+i)n-1]</p> </td> </tr> <tr> <td width="197"> <p>Salvage Value (SV)</p> </td> <td width="126"> <p>&nbsp;$&nbsp;&nbsp;&nbsp;&nbsp; 46.00</p> </td> <td width="102"> <p>&nbsp;$&nbsp;&nbsp;&nbsp;&nbsp; 19.00</p> </td> <td width="183"> <p>0.2 x C</p> </td> </tr> <tr> <td width="197"> <p>Annual Salvage Value (ASV)</p> </td> <td width="126"> <p>&nbsp;$&nbsp;&nbsp;&nbsp; &nbsp;21.84</p> </td> <td width="102"> <p>&nbsp;$&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 1.19</p> </td> <td width="183"> <p>SFF x SV</p> </td> </tr> <tr> <td width="197"> <p>Annual Maintenance (AMC)</p> </td> <td width="126"> <p>&nbsp;$&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;6.11</p> </td> <td width="102"> <p>&nbsp;$&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;1.82</p> </td> <td width="183"> <p>0.15 x FAC</p> </td> </tr> <tr> <td width="197"> <p>Annual Cost (AC)</p> </td> <td width="126"> <p>&nbsp;$&nbsp; &nbsp;&nbsp;&nbsp;24.97</p> </td> <td width="102"> <p>&nbsp;$&nbsp; &nbsp;&nbsp;&nbsp;12.74</p> </td> <td width="183"> <p>FAC+AMC-ASV</p> </td> </tr> <tr> <td width="197"> <p>Cost of distilled water production per liter (CPL)</p> </td> <td width="126"> <p>&nbsp;$&nbsp; &nbsp;&nbsp;&nbsp;0.131</p> </td> <td width="102"> <p>&nbsp;$&nbsp; &nbsp;&nbsp;&nbsp;0.033</p> </td> <td width="183"> <p>AC/M</p> </td> </tr> <tr> <td width="197"> <p>Selling Price (SP)</p> </td> <td width="126"> <p>&nbsp;$&nbsp; &nbsp;&nbsp;0.300</p> </td> <td width="102"> <p>&nbsp;$ &nbsp;&nbsp;&nbsp;0.300</p> </td> <td width="183"> <p>&nbsp;</p> </td> </tr> <tr> <td width="197"> <p>Payback period</p> </td> <td width="126"> <p>5 years 10 months</p> </td> <td width="102"> <p>11 months</p> </td> <td width="183"> <p>ln[(SPxM)/((SPxM)-(Cxi))]/ln(1+i)</p> </td> </tr> </tbody> </table> <p>&nbsp;</p> Wesley Jeevadason Aruldoss Padmini S Bharatiraja C Copyright (c) 2021 Wesley Jeevadason Aruldoss, Dr. S. Padmini, Dr. C. Bharatiraja 2021-10-07 2021-10-07 1 01 Facile Synthesis of Boron doped NiCu for efficient methanol oxidation: Selectivity towards value-added fomate formation. https://spast.org/techrep/article/view/631 <p>The impending nature of the fossils fuel and to mitigate the CO<sub>2</sub> content, the search for clean renewable energy sources has become imperative. In order to fulfil the energy demand of growing population, considerable research work has been focused on methanol fuel cells. However, bewilderment in noble metals, such as high cost and CO poising hinders their practical application.[1-2] In order to replace the noble metals, design and development of non-noble metal-based electrocatalyst has gained numerous attentions owing to their high mobility, low working temperature, and low emission of greenhouse gases. Among different non noble metals, spinel structure of nickel copper oxide has been considered as a good catalyst for methanol oxidation reaction due to its partially filled d-valence orbitals, which induces spin and orbital degrees of freedom, resulting in better electrochemical activity. Nonetheless, the oxidation of methanol at nickel copper electrocatalyst still suffers due to its low porous structure and electrical conductivity. [3] In order to alleviate the above issues, researchers adopted different strategy, such as incorporation of polymer, carbon based materials, doping of heteroatom, etc to non noble metals. Among them, heteroatom doping namely boron has gained numerous attentions owing to its tunable electronic structure of host electrocatalysts, which helps in absorbing more methanol effectively. Moreover, simple boron combustion and calcination technique was adopted to synthesize nickel copper oxide and boron doped nickel copper oxide. Interestingly unlike other noble metals, boron doped nickel copper oxide yield formate as primary intermediate. [4] It is worth noting that, this formate/formic acid results as a partial oxidation product in non noble metal based methanol oxidation reaction and it is an important industrial intermediate that can be used in diverse chemical industry fields, such as rubber, pharmaceutical, dye, direct formate fuel cell and hydrogen storage. However, traditional industrial formic acid production usually employs complicated multi-step processes and requires large amounts of energy consumption, resulting in its high cost. Considering the industrial price, a ton of methanol might be sold at about $350, which can be useful in converting electricity at low cost as compared with other techniques such as battery, tidal plant, etc. Moreover, the byproduct can be used effectively in various industries, which also reduces the cost and preserve the environment. Hence, generation of electricity along with production of value-added products, can resolve both energy and environmental crisis. In this present work, we have synthesized highly electroactive boron doped nickel copper oxide for efficient methanol oxidation reaction. [5] The prepared electrocatalyst was characterized with various spectroscopy studies such as XRD, FT-IR and XPS spectroscopy. The effectiveness towards methanol oxidation reaction was studied by employing cyclic voltammeter and chronoamperometry studies. This work opens up a new insight for the designing and fabricating non noble metal based methanol oxidation reaction.&nbsp;</p> Naveen Kumar T. R Copyright (c) 2021 Naveen Kumar T. R 2021-09-16 2021-09-16 1 01 Decrypting the charge-storage properties of CeO2 decorated α-nickel hydroxide in battery-type supercapacitors https://spast.org/techrep/article/view/2097 <p>Developing immensely competent, green energy storage device with outstanding power and energy competences is of extreme mandate in the contemporary electronic era. An enthralling energy storage device, supercapacitors have quicker charge/discharge mechanisms (within seconds), high specific power (&gt;163 W kg<sup>-1</sup>), improvable specific energy, and lengthier cycle life (1,000-20,000 cycles) [1-4]. Electrode is the predominant element that governs the overall performance of the supercapacitor device. Electroactive metal oxide with prominent oxidation states and high conductivity like MnO<sub>2</sub>, Co<sub>3</sub>O<sub>4</sub>, CeO<sub>2</sub>, etc., embrace good chemical stability, but are deficit in realizing exemplary electrochemical proficiency. Cerium oxide being a budget-friendly lanthanide-based metal oxide, has good conductivity, and decent electrochemical activity. N. Maheswari et al., developed hexagonal CeO<sub>2</sub> nanoparticles with a specific capacitance of 927 F g<sup>−1</sup>, via hydrothermal method [5]. CeO<sub>2</sub> when combined with suitable electroactive material, have been reported to improve the ion and charge transportation pathways, leading to enhancement in the charge-storage properties laterally with remarkable cyclic stability [6-7]. Environmentally-benign, abundantly obtainable, nickel hydroxide Ni(OH)<sub>2</sub>, a battery-type supercapacitor material, owns interesting electrochemical signatures but lack in conductivity (~10<sup>−13</sup> to 10<sup>−17</sup> S cm<sup>−1</sup>) and mechanical robustness on repeated charge-discharges. These drawbacks hamper the possibility to achieve the theoretically predicted capacitance. Integration of battery-grade Ni(OH)<sub>2</sub> with highly stable and conductive supercapacitive material like CeO<sub>2</sub> can abridge the ion diffusion distance, widen the charge-storage competencies.</p> <p>Earlier works on co-existence of Ce and Ni ions in the host material, boosted the charge/mass transfer kinetics, improved the specific surface area, and amended the electrochemical activity. Z. Liu et al., reported vertically grown CeO<sub>2</sub>/Ni(OH)<sub>2</sub> over N, O and S doped carbon foam with accelerated charge transfer and enhanced electrochemical activity as high efficiency electrocatalyst for oxygen evolution reaction (OER) application [8]. Moreover, CeO<sub>2</sub>-Ni(OH)<sub>2</sub> architectures had interesting non-enzymatic glucose detection [9] and H<sub>2</sub>O<sub>2</sub> sensing properties [10]. These works established that CeO<sub>2</sub>-Ni(OH)<sub>2</sub> composite have remarkable electrochemical activity, and gives hope to serve as an effectual electrochemical supercapacitor electrode material. Through proper tuning of surface properties together with better utilization of both Ni(OH)<sub>2</sub> and CeO<sub>2</sub> surface active sites, superior charge-storage properties could be achieved. Majority of the synthesis strategies are complex and technically exhaustive when extended to industrial scale. Whereas coprecipitation process is an easily scalable and expediently wet-chemical approach to acquire nanomaterial with high uniformity.</p> <p>In the present work, electroactive lanthanide-metal-oxide CeO<sub>2</sub> is decorated over α-Ni(OH)<sub>2</sub> through simplistic coprecipitation method to achieve upgraded surface and electronic properties. The correlation between structural, morphological, and electrochemical properties of the prepared material are analyzed in detail. The unique nanoarchitecture of Ni(OH)<sub>2</sub> nanosheets embedded with CeO<sub>2</sub> spheres empower the ion/electron transport pathways on electrode surface to attain an admirable specific capacity (capacitance) of 257 C g<sup>-1</sup> (960 F g<sup>-1</sup>) at 0.5 A g<sup>-1</sup> with 97.4% capacity retention even after 2000 repetitive redox cycles. The supercapacitor device assembly CeO<sub>2</sub>-Ni(OH)<sub>2</sub>||CeO<sub>2</sub>-Ni(OH)<sub>2</sub> fabricated using the optimal composite, delivers specific energy of 54 W h kg<sup>-1</sup> at a specific power of 1280 W kg<sup>-1</sup> respectively. The superior electrochemical performance of coprecipitated CeO<sub>2</sub>-Ni(OH)<sub>2</sub> establishes the probability of being used as electrode material in futuristic battery-type supercapacitors.</p> Biny R Wiston Shivangi Tewatia Ashok Mahalingam Copyright (c) 2021 Biny R Wiston, Shivangi Tewatia, Ashok Mahalingam 2021-10-08 2021-10-08 1 01 Carbon/MoS2/CuBi2O4 Photocathodes for stable and efficient photoelectrochemical water splitting https://spast.org/techrep/article/view/2824 <p>Hydrogen is contemplated a favouring environmentally friendly energy carrier for substituting outmoded fossil fuels [1-2]. In this context, photoelectrochemical cells efficiently convert solar energy directly into H<sub>2</sub>&nbsp;fuel by use of water photoelectrolysis, thereby monolitically conjoining the functions of both light harvesting and electrolysis.&nbsp;In such devices, photoanodes and photocathodes carry out the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), respectively [1]. Here, we focussed on tetragonal p-type terinary semiconductor metal oxide CuBi<sub>2</sub>O<sub>4</sub> and its bandgap 1.5 to 1.8 eV [3-4]. In this work, we successfully fabricated FTO/CuBi<sub>2</sub>O<sub>4</sub> has photocathode and compared its photoelectrochemical behaviour with FTO/CuBi<sub>2</sub>O<sub>4</sub>/C. in particularly functional role of charge selective and protection layer, which improved both photocurrent density and stability of photocathodes. Here additionally charge transfer resistance of FTO/CuBi<sub>2</sub>O<sub>4</sub>/C and FTO/CuBi<sub>2</sub>O<sub>4</sub> were analysed through Electrochemical Impedance Spectra.&nbsp; Further systematic study on optical, structural and raman studies were done. X-Ray Diffraction (XRD) studies revealed kusachiite structure with average crystallite size of 43.92 nm, wavelength range of 300 – 1200 nm absorbance spectra were recorded and observed broad absorption spectrum at 450 to 800 nm. Atomic force microscopy (AFM) were used to analysis surface roughness difference of both FTO/CuBi<sub>2</sub>O<sub>4</sub>/C and FTO/CuBi<sub>2</sub>O<sub>4</sub>. Linear sweep voltammetry, chronoamperometry, Mott Schotkky plot and Electrochemical impedance spectra were performed to confirm the photoelectrochemical behaviour in 0.1 M of NaOH aqueous solutions (pH = 12.5).</p> VRUNKUMAR K. Sitaaraman SR Dr Raja Sellappan Copyright (c) 2021 VRUNKUMAR K., Sitaaraman SR, Dr Raja Sellappan 2021-10-17 2021-10-17 1 01 Transition Metals Based Layered Materials for Green Hydrogen Production https://spast.org/techrep/article/view/803 <p>The increasing demand for energy and serious concerns on the environmental problems arising from the utilization of unrenewable fossil fuels have led to the emergency and necessity of developing critical techniques and materials for green and sustainable energy sources. Hydrogen made by water splitting is one of the most promising green energy to replace the fossil fuels. However, the high energy barriers involved in water splitting reaction mean sluggish reaction kinetics, making the production cost of the intended fuel products prohibitively high. Therefore, effective catalysts with advanced activity and stability are greatly needed for realizing the industrial application of hydrogen production to overcome the above mentioned energy shortage and environment contamination problems.[1] In this talk, I’d like to<br>present our latest work on design and synthesis of transition metals based electrocatalysts for efficient hydrogen production via water splitting. Specifically, the strategies for chemical composition tuning, surface/interface engineering,[2,3] microstructure control,[4] and active sites manipulation[5] for improving the catalytic performance of the catalysts will be presented, and the revealed structure-performance relationship as well as the catalytic mechanism will also be discussed.</p> Xia Long Shihe Yang Copyright (c) 2021 Xia Long, Shihe Yang 2021-09-18 2021-09-18 1 01 Preparation of MoS2/Curved Graphene Nanosheets based composite as a remarkable electrode material for high-performance supercapacitors https://spast.org/techrep/article/view/152 <p><strong>Abstract </strong></p> <p>MoS<sub>2</sub> was prepared with flower-like microspheres by hydrothermal method using ammonium molybdate and thiourea. Followed by curved graphene nanosheets (CGN) was synthesized from MWCNTs by a two-step process, including oxidation and reduction via modified Hummers method using sodium nitrate, sulfuric acid, and potassium permanganate, and NaBH<sub>4</sub>. After the reduction, the solid sample was collected and washed with ethanol and deionized water and vacuum-dried at 60 °C to obtain the CGN. XRD pattern of MoS<sub>2</sub> nanosheets showed diffraction peaks at 14.12, 33.57, and 58.79 correspondings to the planes of (002), (101), and (110). The intensity of diffraction peaks of the hexagonal phase indicated the crystalline structure of flower-like MoS<sub>2</sub> nanosheets. Hummer’s method of oxidation and following reduction process will lead to the unzipping of MWCNT to curved graphene nanosheets (CGN). XRD pattern for MWCNT showed a plane (001), as evidenced by a peak at 2θ =26.05.° After reduction with NaBH<sub>4</sub>, this peak completely disappeared, and a very broad peak appeared at around 23.2° which corresponds to an interlayer spacing of about 3.7 Å.&nbsp;First, 3 mg of prepared MoS<sub>2</sub> was dispersed in 2 ml DI water and sonicated for 5 min and 3 mg of CGN was dissolved in 2 ml DI water and sonicated. From these dispersions, we found that MoS<sub>2</sub> dispersion was not stable compared to CGN in DI water. Next, 3 mg of CGN and 3 mg of MoS<sub>2</sub> were mixed in 2 mL water and sonicated for 5 min. MoS<sub>2</sub>/CGN dispersion was a stable dispersion in DI water. This composite was used to prepare anode material for supercapacitors. We have studied the electrochemical properties of MoS<sub>2</sub>/CGN after coating on a glassy carbon electrode. MoS<sub>2</sub>/CGN loaded electrode showed better capacitive performance, a specific capacitance of (C<sub>sp</sub>) of 621 F g<sup>-1</sup> at 1 A g<sup>-1</sup> with H<sub>2</sub>SO<sub>4</sub> with good capability. MoS<sub>2</sub>/CGN loaded electrode also showed extraordinary cycling stability with 86.1% capacitance maintenance after 1000 nonstop charge-discharge cycles at a current density of 1 A g<sup>-1</sup>.</p> <p>&nbsp;</p> Desai Prashant Hanamantrao Copyright (c) 2021 Desai Prashant Hanamantrao 2021-09-02 2021-09-02 1 01 Green Synthesis of Corn Cob derived Carbon dots and Its Applications as Electrolyte Additive for Lithium Batteries https://spast.org/techrep/article/view/1848 <p>Carbon quantum dots (CDs), a zero-dimensional nanoparticles, exhibit uniform particle sizes, good biocompatibility, low cytotoxicity and chemical inertness, easy functional modification, and adjustable fluorescence [1, 2].The outstanding optical and electrical properties of CD’s is attributed to its unique quantum confinement and edge effects [3, 4]. In addition, tunable band gap and stable fluorescence of CD’s makes it as the appropriate candidate for replacing high cost inorganic semiconductor quantum dots such as Zinc sulfide (ZnS), cadmium selenide (CdSe) and cadmium sulfide (CdS) [5, 6].The carbon precursors viz., citric acid, glycine are widely used in synthesizing carbon quantum dots with controlled particle sizes (~10 nm) via., hydrothermal or microwave assisted synthetic routes. Alternatively, green synthetic approach involving various bio-related materials including juices, coffee grounds, egg whites and even chocolates have also been explored. In this work, a novel attempt has been made in synthesizing photo luminescent carbon quantum dots using a low cost green material viz., corn cobs by adopting hydrothermal synthetic approach. The synthesized carbon dots were characterized using various characterization tools to understand its chemical, structural and morphological characterizations. X-ray diffraction (XRD) studies revealed the formation of graphitic crystalline features with average d-spacing value of ~0.42 nm in the synthesized carbon quantum dots. The presence of various functional sites viz., &gt;C=O and C-O-C groups are further corroborated using the chemical characterization tools using Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Morphological characterization using transmission electron microscopy (TEM) corroborated the formation of CD’s with average particle sizes of 5~10 nm. The application aspect of the synthesized CD as the deposition regulating additive in lithium metal anode batteries has been explored. Lithium/lithium (Li/Li) symmetric cells fabricated using CD additive loaded LiPF<sub>6</sub> salt electrolyte displayed small over potential (130 mV at 2 mA/cm<sup>2</sup>) and relatively good cycling stability for 200 cycles at 2 mA/cm<sup>2</sup>, when compared to Li/Li cells fabricated using commercial electrolyte system (600mV at 2mA/cm<sup>2</sup>). Full cells (NMC/Li) fabricated using lithium nickel manganese cobalt oxide (NMC) cathode, lithium metal anode and CD additive loaded electrolyte showed about 20 % increment in specific discharge capacity (measured at the current density of 0.1 mA/cm<sup>2</sup>) in comparison to the coin cells fabricated using commercial electrolyte, signifying the positive contribution of CD additive in controlling the lithium dendrite growth.</p> Padmapriya Arumugam Copyright (c) 2021 Padmapriya Arumugam 2021-10-08 2021-10-08 1 01 Development and Control of a Photovoltaic Fed Flywheel Energy Storage System for Power Conditioning https://spast.org/techrep/article/view/647 <p>The concept of newer energy storage and power conditioning using suitable controllers in a solar photovoltaic fed flywheel energy storage system (FESS) is presented in this work.&nbsp; The power from a solar photovoltaic arrangement is harvested using a Sinusoidal Pulse Width Modulated (SPWM) DC-DC converter to provide a controlled, efficient and regulated output to drive the Flywheel Energy Storage System. The FESS is designed with the BLDC motor as prime mover that drives a flywheel of cylindrical mass of suitable material and radius. The alternator connected in the same shaft of the prime mover and flywheel powers an electrical load of 1kW. The dynamic stability of the system is taken care by the flywheel, while reliability is ensured using a well designed controller unit. The solar PV arrangement with its controller was simulated using MATLAB, while the flywheel energy storage system was simulated using ANSYS. Based on the simulation results, a working model was fabricated, installed and tested for the required operation. Test results were compared; graphical representations are given to substantiate the working of the flywheel energy storage system.</p> Vijayalakshmi M Ramaprabha R Copyright (c) 2021 Vijayalakshmi M, Ramaprabha R 2021-09-16 2021-09-16 1 01 Role of Na Precursors on the Sintering and Ionic Conductivity of NASICON type Na excess Na3Zr2Si2PO12: A Comparative Study https://spast.org/techrep/article/view/1455 <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The research and developments on all-solid-state Na-ion batteries as an alternative to Li-ion batteries have received considerable scientific attention due to the larger availability of low-cost Na resources. In addition, the use of solid electrolyte in the solid-state battery provides additional safeties and thermal stabilities in contrast to the battery relying on conventional liquid electrolytes [1]. Investigations on the structural and transport parameters of different Na-based solid electrolytes play a crucial role on the development of all-solid-state Na-ion batteries. NASICON type Na<sub>3</sub>Zr<sub>2</sub>Si<sub>2</sub>PO<sub>12</sub> (NZSP) solid electrolytes exhibit good ionic conductivity (~10<sup>-4</sup> S cm<sup>-1</sup>) and high thermal and chemical stabilities among the known oxide, sulphide and hydride based solid electrolytes. However, they require high sintering temperatures and often occur with undesired secondary phases [2]. Addition of excess Na or tune in the stoichiometry of other elements present is one of the most effective strategies to enhance the conductivity of NZSP.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; NZSP prepared by the solid state reaction using Na<sub>3</sub>PO<sub>4</sub> as Na precursor exhibits higher ionic conductivity in comparison to the same synthesized by sol-gel process [3]. In this work, NZSP with excess Na materials are prepared by solid state reaction using four different types of Na precursors such as Na<sub>2</sub>CO<sub>3 </sub>(NC), Na<sub>3</sub>PO<sub>4 </sub>(NP), NaF (NF) and Na<sub>2</sub>SiO<sub>3 </sub>(NS) as excess Na source. Although same Na stoichiometry is maintained in all the Na-excess NZSP materials, the choice of the precursors results a change in stoichiometry of other elements like P, Si and O present in the bare-NZSP. The structural and transport properties of the Na excess NZSP materials are studied by varying their sintering temperature from 1100<sup>o</sup>C to 1250<sup>o</sup>C.&nbsp; The X-Ray diffraction results confirm monoclinic NASICON as main phase in all the investigated materials. FT-IR analysis confirms the presence of main functional groups in all the samples. The ionic conductivity measurements at different frequencies are carried out using impedance spectroscopy. All NZSP with excess Na materials exhibit higher ionic conductivity in comparison to the bare NZSP conductivity. The influence of Si/P ratio on the total ionic conductivity of Na excess NZSP is also highlighted. Among the investigated materials, Na excess NZSP material using Na<sub>2</sub>CO<sub>3 </sub>(NC) as Na precursor sintered at 1200<sup>o</sup>C exhibited highest ionic conductivity (<strong>Fig. 1</strong>). The ionic transport number measurements by the DC polarization technique confirm the ionic nature of the principal charge carriers.</p> Y Bhaskara Rao Copyright (c) 2021 Y Bhaskara Rao 2021-10-07 2021-10-07 1 01 Thermomechanical properties of artificial muscle based on silicon-carbon fibre composite https://spast.org/techrep/article/view/684 <p>Artificial muscles represent a class of biologically inspired materials that can reversibly contract and expand by application of an external stimuli, such as temperature [1], pressure [2], voltage [3], or current [4]. By potential conversion of muscle's mechanical deformation to useful work or electricity, it can be used as a means for energy storage as well. Recently, artificial muscles have become a popular topic in both academic and industrial fields, where search for innovative actuation devices based on various mechanisms have been initiated and advanced materials with superior performances in many aspects compared to those of natural muscles have been developed. Among other polymers, which can serve as a basis for constructing artificial muscles, silicon rubber possesses many advantages. This elastomer is relatively cheap and possesses useful properties, such as ease manufacturing and shaping, non-reactivity with most chemicals, stability, good resistance to extreme temperatures, ability to operate normally from −100 to 300 °C, biocompatibility, which allows one to use it in many medical applications where contact with skin, water, blood, active ingredients, etc., is needed. At the same time, silicone rubber has low tensile strength, poor wear and tear wear properties and is too soft for some mechanical applications, which stimulates development of new composites that overcome these drawbacks.</p> <p>The objective of this work is to demonstrate a novel prototype for a composite artificial muscle where specific filler is used to improve its mechanical and thermal conducting properties. Specifically, the muscle is based on the composite of a silicon rubber and a carbon fiber. The latter serves for reinforcement of the mechanical strength of the elastomer and improvement of its thermal conductivity properties for thermomechanical applications.</p> <p>First, the elastomer is shown to be able to lift the cargo which is more than one order of magnitude higher than the weight of the sample itself (Fig. 1a). In this sense, the muscle can be used to store the mechanical energy. Second, our studies show how the extent and orientation of the carbon fiber load in the polymer sample influences the rate and extent of the sample deformation. Particularly, it is demonstrated that the relative deformation of the sample can reach up to 5% upon heating to 70-80 <sup>0</sup>C. We also demonstrate that depending on the fiber orientation in the sample one can control the sample rigidity and thus either to suppress or to promote the sample deformation (Fig. 1b). Suppression of the sample deformation is due to increasing mechanical strength, whereas its promotion is due to improved thermal conductivity of the composite sample. A simple control of thermomechanical properties of the muscle and relatively cheap material it is composed of makes it perspective for applications in such fields as collection and storage of thermal energy.</p> <p><img src="https://spast.org/public/site/images/olegdimitriev/fig1a.png" alt="Fig1a" width="403" height="302">&nbsp;<strong>a<img src="https://spast.org/public/site/images/olegdimitriev/fig1b.png" alt="" width="403" height="290"></strong><strong>b</strong></p> <p><strong>Fig. 1.</strong> (a) Lifting of a coin by a silicon muscle upon thermal exposure; (b) Relative deformation of a composite muscle as a function of the filler (vol. %) oriented perpendicular and parallel to the sample axis, respectively.</p> <p>&nbsp;</p> <p><strong>References</strong></p> <p>[1] J. Leng, X. Lan, Y. Liu, S. Du, Progress in Materials Science <strong>56</strong>, 1077-1135 (2011). <a href="https://doi.org/10.1016/j.pmatsci.2011.03.001">https://doi.org/10.1016/j.pmatsci.2011.03.001</a></p> <p>[2] F. Daerden, D. Lefeber, European journal of mechanical and environmental engineering, <strong>47</strong>, 11-21 (2002). <a href="http://www.robotikk.com/inf5207/Daerden_Lefeber_EJMEE.pdf">http://www.robotikk.com/inf5207/Daerden_Lefeber_EJMEE.pdf</a></p> <p>[3] C. Ohm, M. Brehmer, R. Zentel, Advanced Materials <strong>22</strong>, 3366-3387 (2010). <a href="https://doi.org/10.1002/adma.200904059">https://doi.org/10.1002/adma.200904059</a></p> <p>[4] M. D. Lima, N. Li, <em>et al</em>. Science, <strong>338</strong>, 928-932 (2012). doi/10.1126/science.1226762</p> <p>&nbsp;</p> Oleg Dimitriev Polina Dimitriieva Tamara Doroshenko Alexander Fedoryak Copyright (c) 2021 Oleg Dimitriev, Polina Dimitriieva, Tamara Doroshenko, Alexander Fedoryak 2021-09-16 2021-09-16 1 01 Defect-induced FexNi1-xSe2 nanoparticles for enhanced electrocatalytic performances towards hydrogen and oxygen evolution reactions https://spast.org/techrep/article/view/290 <p>Energy demand is increasing with the increasing global population and the natural source of energies such as petroleum, natural gas, coal are very limited and are continuously depleting. Moreover, prolonged use of these fossil fuels release greenhouse gases and pollutes the environment. Therefore, the present world requires a clean and renewable energy source to fulfil the energy demand as well as to safeguard the environment. Generation of hydrogen and oxygen by electrochemical water splitting would be a quality choice, since the by-product here is water and the source is also water [1-2]. To date, noble metal based electrocatalysts such as Pt/C, RuO<sub>2</sub>, and IrO<sub>2</sub> are the best-known electrocatalysts for hydrogen and oxygen evolution reactions (HER, OER) with an overpotential close to the theoretical values and have superior catalytic behaviour [3-4]. However, it remains a great challenge to produce hydrogen and oxygen at a large scale using noble materials, due to their high cost and less abundance. In search of alternatives for noble materials, transition metal based catalysts can be a good choice, since they are cost effective, more abundant and have good electrical conductivities [5-6]. Among them, transition metal dichalcogenides and their bimetallic counter parts are well known for their superior electrochemical properties and high catalytic activities [7]. Moreover, inducing defects in the crystal structure creates more active sites, which enhance the electrocatalytic performance towards HER and OER [8]. Herein, for the first time we report a defect-induced Fe<sub>x</sub>Ni<sub>1-x</sub>Se<sub>2</sub> for the electrochemical water splitting. The electrocatalyst Fe<sub>x</sub>Ni<sub>1-x</sub>Se<sub>2</sub> of different molar ratios were developed by hydrothermal method and the defects were created by calcination. Thus prepared materials were characterized by XRD, TEM and EDX mapping. Before and after calcination, all the XRD peaks remain same which indicates that the phase of the crystal structure is unaffected however, the peak distortion after calcination indicates the occurrence of the defects in the crystal structure. The TEM images of both Fe<sub>0.25</sub>Ni<sub>0.75</sub>Se<sub>2</sub> and DI- Fe<sub>0.25</sub>Ni<sub>0.75</sub>Se<sub>2</sub> (defect induced) show the “d” spacing with an average distance of 0.18 nm corresponds to (311) plane and 0.26 nm corresponds to (210) plane, which confirms that even after calcination there is no change in the “d” spacing but, DI-Fe<sub>0.25</sub>Ni<sub>0.75</sub>Se<sub>2 </sub>exhibits disordered lattice fringes which are due to distortion in the crystal structure. Among different molar ratios of Fe<sub>x</sub>Ni<sub>1-x</sub>Se<sub>2</sub>, DI-Fe<sub>0.25</sub>Ni<sub>0.75</sub>Se<sub>2 </sub>showed the high HER activity with a low overpotential of 128 mV to reach a current density of 10 mA/cm<sup>2</sup> with a Tafel slope of 37.9 mV/dec in 0.5 M H<sub>2</sub>SO<sub>4</sub>. Similarly, for OER, it showed high performance at a low overpotential of 205 mV for 10 mA/cm<sup>2</sup> current density with a Tafel slope of 55.5 mV/dec in 1 M KOH. Moreover, the developed electrocatalyst was stable in the acidic and alkaline medium even after continuous electrolysis for 12 h.</p> Abdul Kareem Copyright (c) 2021 Abdul Kareem 2021-09-14 2021-09-14 1 01 Pillared Assembly of Layered Double Hydroxides and Polyoxometalates: A Sole Approach for Energy Storage Devices https://spast.org/techrep/article/view/1383 <p>In the upcoming years the world will move to the serious energy crisis problem as the non-renewable resource like fossil fuels, gasoline, and coal will be exhaust in the future. The usage of renewable resources such as wind energy, solar energy, tidal energy, and electrical energy etc., will impede and resolve the issue. From the different energy resources, during the conversion of one form of energy to another, the energy can be stored and utilized as the useful form. During the conversion of chemical energy to electrical energy, it will be utilized in storage and conversion devices like supercapacitors and batteries. With this important reminder, the focus is primarily on the development of the storage and conversion, especially for symmetrical supercapacitors [1] and Li-ion batteries [2]. To sort advance in the above systems, the electrode materials, plays a crucial role. Therefore in this work the suitable electrode material to acts as an electrode for the symmetrical supercapacitor and Li-ion batteries are developed. Polyoxometalate (POM), type of inorganic compound in which the transition metal such as Mo, W, V and Nb in the higher oxidation are coordinated to the central metal ions P, Si, and As, etc via the shared oxygen atoms to form 3D open framework structure. Mainly the electrochemical properties including multi-redox properties and electron sponge behaviour has invoked the interest to utilize POM as electrodes in the storage and conversion devices [3]. With a keen interest in POM, in our previous work [PMo<sub>10</sub>V<sub>2</sub>O<sub>40</sub>]<sup>5-</sup>keggin-type POM was developed and used as electrodes for Li-ion batteries. Both for anode and cathode as a result of multi-redox reaction of the Mo<sup>6+</sup>/Mo<sup>5+</sup> and V<sup>5+</sup>/V<sup>4+</sup> redox couples, the specific capacity of 1414 mAh g<sup>-1</sup> and 332 mAh g<sup>-1</sup> is achieved in the initial cycle at 0.1C rate. But after 50 cycles, the capacity fading happens as the result of dissolution of POM in the electrolyte [4]. The dissolution problem are resolved by combining the POM with the suitable substrate of Layered Double Hydroxide (LDH), where the pillaring between LDH and POM are developed in this work. The electrostatic interaction found between POM and LDH material will further enhance the material stability during the cycling performance, which results in the high cycling stability with minimal capacity fading in case for Li-ion batteries. With these positive outcomes for Li-ion batteries, the as-prepared POM@LDH composite will be used as an electrode for symmetrical supercapacitors. The as-prepared composite will be carefully studied from various physical characterizations to further confirm the successful pillaring of POM@LDH. In CR2032 coin-type cells, the Li-ion half cells will be assembled with Li metal as the reference electrode. In case for supercapacitors, in 6M KOH the electrodes are tested for the capacitance value to exhibit high power and energy density. The electrochemical studies including Cyclic Voltammetry (CV), charge/discharge and Electrochemical Impedance Spectroscopy (EIS) further provides greater insights as Li-ion batteries and supercapacitors. Pillaring of LDH with POM opens new findings in the energy storage and conversion devices.</p> Priyadarshini Pushparaj Shanmugan Kumaran Copyright (c) 2021 Priyadarshini, Pushparaj Loganathan, Swaminathan Shanmugan, Kumaran Vediappan 2021-09-30 2021-09-30 1 01 Comparative study of hydrocarbon-based Polymer Membranes in Proton Exchange Membrane Fuel Cells https://spast.org/techrep/article/view/1453 <p>Research related to climate change shows a worrying trend warranting an immediate course correction. Finding alternative fuels to traditional fossil fuels is one of the focus areas for research in recent times. With automobiles being one major consumer of fossil fuels, many greener alternatives are being studied as an energy source for automobiles. Two of the most promising alternatives include lithium-ion batteries and fuel cells. With more data regarding the environmental impacts and uncertainty regarding the price of lithium, fuel cells are a prominent area for future research. The most crucial component in a fuel cell is a proton exchange membrane (PEM).</p> <p>Nafion is the most commonly used material in the production of a membrane in Proton Exchange Membrane Fuel Cells [1]. However, Nafion has several drawbacks such as a low operating temperature range, the presence of fluorine, and high cost [2-4]. Recent studies have explored hydrocarbon-based Proton Exchange Membranes (PEMs) as a potential replacement to Nafion-based membranes. Since most laboratory testing on PEMs is conducted using a standardized protocol, it is possible to compare multiple materials in a review study. In this work, we compare hydrocarbon-based PEMs sterically hindered triphenylated pyridine-containing polyphenylene (sTPPyPP) and triphenylene phenyl polyphenylene (sTPPPP) [4],&nbsp; Pendant dual sulfonated BPAEK-SDPA multi-block copolymer[5], cross-linked sulfonated poly (arylene ether sulfone) membranes (C-SPAES_X) (where X indicates the weight percent of cross-linker in sulfonated poly(arylene ether sulfone)[3], sulfonated polyphenylene (SPP-QP) [2] and Permion<sup>TM</sup> [6] membranes.</p> <p>PEMs are analysed using techniques such as cyclic voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Nyquist plot. The mechanical testing is performed using standards under ASTM D-638.&nbsp; The membranes are compared based on their fuel cell performance (maximum power density) (fig. 1), proton conductivity (fig. 2), water uptake (fig. 3), and their mechanical properties. From the results obtained, we infer that the hydrocarbon-based PEM shows better fuel cell performance, proton conductivity and mechanical strength than Nafion PEM, Nafion on the other hand shows better dimensional stability compared to hydrocarbon-based PEMs. However, it is worth noting that the development of these membranes is in its nascent stage, and further research in the field will lead to improved dimensional stability.</p> <p>The synthesis and membrane fabrication process used in all the studies vastly varies from each other in terms of complexity and cost. Economic factors will also play an important role in selecting the most suitable membrane. It should also be considered that the characterization studies are conducted in a laboratory environment using deionized water over a short duration of time. Future studies warrant the incorporation of real-world factors regarding water quality and long term usage before the fuel cells with hydrocarbon-based PEMs can be used for commercial applications.</p> <p>This study underlines the potential of fuel cells as an environmentally friendly alternative to both fossil fuels and lithium-ion batteries. With no requirement of large-scale mining operations and use of readily available water and organic compounds for operation and production respectively, the use of hydrocarbon-based PEM Fuel cells will be instrumental in achieving the goals such as net-zero carbon emissions that are important for a sustainable future.</p> Amey Dukle Copyright (c) 2021 Amey Dukle 2021-10-07 2021-10-07 1 01 SODIUM BOROHYDRIDE DECOMPOSITION CATALYSTS BASED ON NICKEL FERRIES OF FUEL CELLS https://spast.org/techrep/article/view/681 <p>1</p> Serhii Lesik Copyright (c) 2021 Serhii Lesik 2021-09-18 2021-09-18 1 01 Recent advances in efficient nanostructured photocatalysts for hydrogen fuel production: A short review https://spast.org/techrep/article/view/993 <p><span style="font-weight: 400;">Hydrogen is considered to be leanest energy of the future, in order to empower the sustainable development goal number 7.&nbsp; There are various techniques developed to produce the H</span><span style="font-weight: 400;">2</span><span style="font-weight: 400;"> gas, photocatalytic H</span><span style="font-weight: 400;">2</span><span style="font-weight: 400;"> generation from water splitting is fund to be clean and green technology which is in line with the global environment and energy suitability. It involves separation of charge, migration of charge, chemical reaction on the surface. Various kinds of photocatalysts are used which are made of metal oxides, metal chalcogenides and graphene based nanocomposites. This review describes the development of various photocatalyst such as TiO</span><span style="font-weight: 400;">2</span><span style="font-weight: 400;">, ZnO, MoS</span><span style="font-weight: 400;">2</span><span style="font-weight: 400;">, and their composites.&nbsp; The three-way nitrogen-doped carbon tube covered&nbsp; MoS</span><span style="font-weight: 400;">2</span><span style="font-weight: 400;">&nbsp; (TNCT@MoS</span><span style="font-weight: 400;">2</span><span style="font-weight: 400;">) was reported to be more efficient photocatalyst. SEM images, XRD results and diffraction patterns of above composites were described to correlate with the photocatalytic property. The production of hydrogen using TNCT@MoS</span><span style="font-weight: 400;">2</span><span style="font-weight: 400;"> was found to be much more productive than usual MoS</span><span style="font-weight: 400;">2</span><span style="font-weight: 400;">. In addition to metal oxide and sulfide, the review also covers the photocatalytic behaviour of graphene, and S/Se based metal chalcogenide based compounds and composites (MCCs) were also discussed. The structural feature of all these important photocatalyst using XRD, SEM, EDX, UV-Vis techniques were revealed. Finally, the photocatalytic H</span><span style="font-weight: 400;">2</span><span style="font-weight: 400;"> generation efficiency, possible mechanism of all these catalyst were compared. </span><span style="font-weight: 400;">In summary, we have reviewed photocatalytic hydrogen production efficiency of metal oxides, metal chalcogenides and graphene based nanocomposites.</span></p> M Kaushik Vijeth B Darshan S M Gopal Krishna Hegade Samarth Kumar Shetty Manjunatha C Copyright (c) 2021 M Kaushik, Vijeth B, Darshan S M, Gopal Krishna Hegade, Samarth Kumar Shetty, Manjunatha C 2021-09-18 2021-09-18 1 01 Supercapacitors – Futuristic energy storage devices for electric vehicles https://spast.org/techrep/article/view/401 <p>Electric vehicles (EVs) are on all time high demand lately. Power storage is, no doubt, the most critical component of an electric vehicle and holds the biggest potential to make electric vehicles supersede internal combustion engine based vehicles.&nbsp;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; An EV is powered by two major energy sources, for instance fuel cells or battery in combination with supercapacitors, to provide steady-state and transient power [1]. The supercapacitors (SCs) are unique to other energy storage devices as they are most widely used for delivery of electrical energy in short time and in appliances demanding long shelf life. They strike a perfect balance amongst capacitors and batteries in the energy storage category. SCs are not just lighter, faster to charge, safer, and non-toxic but can ideally last across millions of charge-discharge cycles without performance degradation [2]. The very long lifetimes regardless of the number of charge cycles give SCs edge over batteries as supercapacitors pretty much rely on physics rather than chemical reactions to store energy. SCs don't degrade in the same fashion as lithium-ion batteries. That could present a huge opportunity in improving the lifespan of an electric vehicle, as well as reducing the environmental impact of using lithium-ion power cells.[3]</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; SCs facilitate the scenarios where one needs to supply or acquire a lot of power in a short time by either capturing the kinetic energy from deceleration that is usually dissipated into heat, or from acceleration and regenerative braking. [3,4] For this reason, supercapacitors are often used on hybrid vehicles, such as the Lamborghini Sian and Toyota FCHV. Therefore, the advancement in supercapacitor technology has huge market requirements, and long-term progress is needed for their successful advancement and commercialization.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; While supercapacitors may not be the whole and sole powering component for EVs, the technology already fits perfectly into hybrid power trains. Electric car makers such as Lamborghini and Tesla are innovating with the technology to add some serious extra performance.&nbsp;New technologies on the horizon promise to bring supercapacitors into full competition with rechargeable batteries</p> <p>This review provides an overview of recent advances in the application of Supercapacitors in electric vehicles and the near future Supercapacitor application for more feasible and sustainable energy storing devices.</p> <p><strong>Table 1.</strong> List of major hybrid electric vehicles using supercapacitors in their power train.</p> <table> <tbody> <tr> <td width="38"> <p><strong>Sl No</strong></p> </td> <td width="132"> <p><strong>Manufacturer </strong></p> </td> <td width="129"> <p><strong>Type of vehicle</strong></p> </td> <td> <p><strong>Role of Supercapacitor</strong></p> </td> <td> <p><strong>The primary energy source</strong></p> </td> </tr> <tr> <td width="38"> <p><strong>1</strong></p> </td> <td width="132"> <p>Lamborghini&nbsp;</p> </td> <td width="129"> <p>Sian car</p> </td> <td> <p>power reserve</p> </td> <td> <p>V12 Engine</p> </td> </tr> <tr> <td width="38"> <p><strong>2</strong></p> </td> <td width="132"> <p>Toyota Motor Corporation,</p> </td> <td width="129"> <p>Yaris Hybrid-R</p> </td> <td> <p>used for Power input during acceleration.&nbsp;</p> </td> <td> <p>Spark ignited IC engine</p> </td> </tr> <tr> <td width="38"> <p><strong>3</strong></p> </td> <td width="132"> <p>Peugeot S.A.</p> </td> <td width="129"> <p>Citroën Ami</p> </td> <td> <p>part of its start-stop fuel-saving systems for faster acceleration.</p> </td> <td> <p>&nbsp;Li-ion battery pack</p> </td> </tr> <tr> <td width="38"> <p><strong>4</strong></p> </td> <td width="132"> <p>Mazda&nbsp;</p> <p>&nbsp;</p> </td> <td width="129"> <p>hybrid cars</p> </td> <td> <p>i-ELOOP (Intelligent Energy Loop) regenerative breaking system</p> </td> <td> <p>&nbsp;</p> <p>-------</p> </td> </tr> <tr> <td width="38"> <p><strong>5</strong></p> </td> <td width="132"> <p>Tesla</p> </td> <td width="129"> <p>Hybrid cars (Model S, Model X, Model Y)</p> </td> <td> <p>power reserve, used for Power Input during acceleration</p> </td> <td> <p>Latest dry battery technology and&nbsp;</p> </td> </tr> </tbody> </table> <p>&nbsp;</p> <p><img src="https://spast.org/public/site/images/ramyap/transmission.png" alt="" width="435" height="312"></p> <p><strong>Fig.1. Schematic of s</strong>uper capacitor – Battery hybrid car power train</p> Ramya P Sudha Kamath M K J Abhilash Preetham Devesh Joshi Swetha KP Copyright (c) 2021 Ramya , Sudha Kamath, Abhilash, Devesh 2021-09-16 2021-09-16 1 01 EXPLORATION OF GRAPHENE AS AN ELECTRODE IN Al – ION BASED SUPERCAPACITOR https://spast.org/techrep/article/view/2018 <p>Due to the shortage of fossil fuel and its impact on the environment, it creates the necessity of energy storage upon the society. Supercapacitor plays a prominent role in energy storage domain, for its high power density nature, but when compared to battery it has low energy density, thus it makes a deficient one for energy storage capacitors. Enhancement of its energy density, along with considering its life time, the amount spent on it, and its toxic nature - (1) Carbon is a wonderful material with effective cost. Graphene is a single layer sheet of graphite, which has a thickness of one atom. Excellent electrical conductivity, high surface area, wide potential window and good chemical stability have made them an effective candidate for energy storage applications. (2) Dispersion of GO sheets and interlayer distance of graphene will affect specific capacitance of the supercapacitor. (3) Interlayer distance of graphene from 0.41nm to 2.51nm has improved their specific capacitance from 43F/g to 141F/g. (4) Cornstalk pith derived carbon nanosheets of specific surface area 805 - 332m2/g gives specific capacitance of 116 - 69 F/g in 6M KOH electrolyte. (5) Carbon nanosheets prepared from carbonizing peanut shell with activation of KOH shows the specific capacitance of 186 F/g in 1 M H2SO4 electrolyte. (6) The specific capacitance of graphene in aqueous electrolyte shows good results of 135 F/g when compared to ionic liquid and organic electrolyte, for the feature of high ionic conductivity, cost effective and non-toxic. (7) Electrolyte aspect and the size of the ion play an important role in accessibility of the surface area of the electrode, which may affect specific capacitance. (8) Aluminium has less ionic radii compared to other metal ions (Li, K, Mg, Na, Zn etc) and also has three electron transfer per ion interaction. (9) It leads to expect improvement on specific capacitance. Let us investigate the performances of graphene on aluminium ion based aqueous electrolyte. The specific surface area of the graphene &nbsp;&nbsp;&nbsp;&nbsp;(~380 m2g-1) is oriented in the direction of (0 0 2) and ID/IG ratio of 0.33. Its electrochemical energy storage activities are analyzed using Cyclic Voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 5M Al(NO3)3 electrolytes. It has the specific capacitance of 17 Fg-1 at 5 mVs-1 and charge transfer resistance of ~ 24 Ω. The charge/ discharge cycles provide high power density and also good columbic efficiency (100%) with no degradation even after 2000 cycles at 1 Ag-1.</p> <p>&nbsp;</p> Shenbagabalakrishnan.B Dr.V.Gayathri Copyright (c) 2021 Shenbagabalakrishnan.B, Dr.V.Gayathri 2021-10-09 2021-10-09 1 01 Enhanced electrochemical super-capacitive performance of Co doped WO3 synthesized by microwave irradiation method https://spast.org/techrep/article/view/1914 <p>Increasing energy demands and the polluting nature of traditional fossil fuels lead humankind to massive energy production from renewable energy sources such as solar, wind, and hydroelectric power. Energy storage is essential to energy production development since classical storage devices are deficient in storing a large amount of energy [1]. Modern electrochemical storage devices such as batteries, fuel cells, and supercapacitors can overcome the problem with the support of nanotechnology. Nanomaterials play a vital role in many fields. It is also making the breakthrough in energy storage devices because of the large surface area and enhancement of the electrochemical properties. According to the storage mechanism and electrochemical characteristics, the storage devices are classified into different types. Among them, supercapacitors have a high specific capacity and power density, but it lacks energy density compared with batteries and fuel cells. The charge storage mechanism in supercapacitors makes further classification into electric double-layer capacitor (EDLC) and pseudo capacitor. EDLC stores the charges by adsorption on the surface of the material. Here, carbon-based nanomaterials such as graphene and carbon nanotubes enhance charge storage with a high surface area.<br>On the other hand, pseudo capacitors store the charges from the faradic redox reaction mechanism. Metal oxide nanomaterials are a good candidate for the pseudo capacitor application. A hybrid supercapacitor is working with both EDLC and pseudo capacitor, which involves the adsorption of charges and faradic redox reaction [2]. RuO2 have a high theoretical specific capacitance (2000 Fg-1) which paved the way to research transition metal oxide nanomaterials as an electrode material for supercapacitors. Since the high cost and toxicity of the RuO2 prevent the material from large production at the industrial level. In order to achieve an excellent specific capacity, many metal oxide nanomaterials are studied with different modified structures and various composites. WO3 is a promising material for energy storage applications due to its cost-effectiveness, environmental friendliness, and excellent electrochemical properties. Unlike RuO2, WO3 exhibits low specific capacitance [3]. In order to overcome a particular low capacity of pure WO3, other transition metal atoms can be doped into the WO3 matrix. Doping the suitable atoms in the lattice matrix is one of the easiest ways to alter the properties of crystalline materials [4]. It is found in the literature that Cobalt (Co) is a suitable dopant material that can enhance the electrochemical properties of pristine WO3 [5]. Various methods were adopted to prepare Pure WO3. Microwave irradiation method is a facile, environmental friendly and less time-consuming method to synthesize a large quantity of materials.</p> <p>Further, this method can be utilized in industrial-level production because of its simplicity. In this work, we have successfully doped different concentrations of Co in WO3 nanomaterial. The formation of WO3 was characterized by XRD and Raman studies. The XRD pattern confirms the monoclinic crystal formation of material while comparing it with existing JCPDS data. Pure WO3 and Co-doped WO3 were matched well with the JCPDS card no 43-1035. HRSEM images show the plate-like nanostructure for pristine WO3, upon doping with Co. elongated plate-like structure is observed. Elongation of structure may lead to the increase the surface area of the material; we believe that this could be the reason for improving the charge storage capacity in Co-doped WO3. The electrochemical performance was investigated by cyclic voltammetry (CV), chronopotentiometry (CP), and electrochemical spectroscopy (EIS). A typical redox reaction was observed for WO3 in CV studies. The specific capacity of the material was calculated from CP curves which were 174 Fg-1 for pure WO3. Cobalt doped samples are expected to give improved results since they showed a significant improvement in previous studies done in Sn doped WO3. Hence, we presume that this Co-doped WO3 can behave as excellent supercapacitor electrode material.</p> Dharmalingam N Rajagopal S Pandiyarasan Veluswamy Paulraj S Kathirvel V Copyright (c) 2021 Dharmalingam N, Rajagopal S, Pandiyarasan Veluswamy, Paulraj S, Kathirvel V 2021-10-09 2021-10-09 1 01 Electrochemical Evaluation of Zinc Terephthalate Metal-Organic Frameworks for Application in Rechargeable Batteries https://spast.org/techrep/article/view/2650 <p><strong>Introduction</strong></p> <p>Metal-organic frameworks (MOFs) made of inorganic ions and organic linkers are attracting attention for their unique properties because of their widely open porous crystal structure. We have recently succeeded in microwave-assisted hydrothermal synthesis of Zn-Terephthalate (TPA) MOF particles [1]. Several different types such as Zn<sub>3</sub>(OH)<sub>4</sub>(TPA)・6H<sub>2</sub>O (Type-I), Zn<sub>4</sub>(OH)<sub>6</sub>(TPA) (Type-II) and Zn<sub>2</sub>(OH)<sub>2</sub>(TPA)・H<sub>2</sub>O (Type-IV) in layered structures were obtained depending on pH of the precursor solution. They exhibited proton-selective reversible redox reactions to indicate possibilities for membrane-free redox batteries [2]. However, their redox potentials, capacity, rate characteristics and electrochemical stability, which are important for the application as a rechargeable battery, have not been clarified. In this study, we investigated the redox activity rate and the crystal structure of Zn-TPA MOFs with different types before and after redox by Cyclic voltammetry (CV) and XRD to evaluate their electrochemical stability.</p> <p><strong>Experimental</strong></p> <p>The precursor solution containing 0.1 M zinc acetate and 0.05 M TPA was basified to pH 7.0, 5.9 and 4.9 to yield Types I, II and IV, respectively. White precipitates after hydrothermal reaction at 150℃ and 30 min. under microwave irradiation were centrifugally collected. 35wt% of MOF pastes were prepared in 2-butanol containing acetylacetone, coated onto an FTO glass substrate to fabricate porous electrodes with a projected area of 2 cm<sup>2</sup>. While the film thickness for Types I, II and IV was about 10, 10 and 25 µm the density was 0.25, 0.45 and 0.68 g cm<sup>-3</sup>, corresponding to porosity of 90, 82 and 73%, respectively, assuming the density of bulk MOFs of Types I and II to be the same as that of Zn<sub>3</sub>(OH)<sub>4</sub>(TPA) reported earlier (2.538 g cm<sup>-3</sup>) [3]. Cyclic Voltammograms (CVs) were measured at Zn-TPA MOFs electrodes in 0.1 M KCl aqueous solution.</p> <p><strong>Result and Discussion</strong></p> <p>The redox reactions of Type-I, II and IV which predicted to undergo proton coupled reversible two electron reduction were assumed as,</p> <p>Zn<sub>3</sub>(OH)<sub>4</sub>(TPA)・6H<sub>2</sub>O + 2H<sup>+</sup> + 2e<sup>-</sup> ⇌ Zn<sub>3</sub>(OH)<sub>4</sub>(TPAH<sub>2</sub>)・6H<sub>2</sub>O&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (1)</p> <p>Zn<sub>4</sub>(OH)<sub>6</sub>(TPA) + 2H<sup>+</sup> + 2e<sup>-</sup> ⇌ Zn<sub>4</sub>(OH)<sub>6</sub>(TPAH<sub>2</sub>)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (2)</p> <p>Zn<sub>2</sub>(OH)<sub>2</sub>(TPA)・H<sub>2</sub>O + 2H<sup>+</sup> + 2e<sup>-</sup> ⇌ Zn<sub>2</sub>(OH)<sub>2</sub>(TPAH<sub>2</sub>)・H<sub>2</sub>O&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (3)</p> <p>The redox potentials of Type-I, II and IV were -1.16, -1.08 and -1.07 V vs. Ag/AgCl as judged from redox peaks in cyclic voltammograms (CVs, Fig. 1). The redox active fraction, which is an index of the percentage of MOF particles in the film that contributed to the reaction, described as,</p> <p>Redox active fraction [%] &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (4)</p> <p>where <em>C</em> is the anodic capacity (C), FW is the formula weight (g/mol), <em>m</em> is the total mass (g) of active materials, <em>F</em> and <em>n</em> are the Faraday constant (C/mol) and electron number, respectively. The redox active fraction of Type-I, II and IV calculated from the equation (1)~(3) reaches 0.22, 0.95 and 0.30%, respectively. While Type-I showed almost unchanging in redox active fraction even at the 100th cycle, Type-II and IV that showed initially higher values than Type-I, gradually decrease, eventually reaching 0.53 and 0.21%, respectively. In fact, the XRD patterns of Type II and IV electrode after 100 CV cycles revealed their conversion into Type I (Fig. 2), described as,</p> <p>Zn<sub>4</sub>(OH)<sub>6</sub>(TPA) + 2e<sup>-</sup> + 2H<sup>+</sup> + 6H<sub>2</sub>O → Zn<sub>3</sub>(OH)<sub>4</sub>(TPAH<sub>2</sub>)・6H<sub>2</sub>O + Zn(OH)<sub>2</sub>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (5)</p> <p>3Zn<sub>2</sub>(OH)<sub>2</sub>(TPA)・H<sub>2</sub>O + 2e<sup>-</sup> + 2H<sup>+</sup> + 11H<sub>2</sub>O → 2Zn<sub>3</sub>(OH)<sub>4</sub>(TPAH<sub>2</sub>)・6H<sub>2</sub>O + TPAH<sub>2</sub>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; (6)</p> <p>Although Type I appears to be the better electrode material for its more negative potential and higher stability, the absolute redox capacity is so small because of its small redox active fraction. That may be caused by poor necking of the particles as suggested from its extremely high porosity. Therefore, control of particle size, conditions of paste preparation and film fabrication need to be reviewed to improve its redox activity.<img src="https://spast.org/public/site/images/satoshi/figure.png" alt="" width="1263" height="1109"></p> Satoshi Chubachi Yuji Hirai Tsukasa Yoshida Copyright (c) 2021 Satoshi Chubachi, Yuji Hirai, Tsukasa Yoshida 2021-10-21 2021-10-21 1 01 Electrochemical studies of novel clay -conducting Poly-o-toluidine hybrid nanocomposites for supercapacitor application https://spast.org/techrep/article/view/2596 <p>Modern society has been developing rapidly and depletion of fossil fuel has led to widespread<br>research for the development of renewable energy technologies. This includes the search for<br>energy conversion and storage devices such as electrochemical capacitors, fuel cells and<br>rechargeable batteries. Supercapacitors (SCs) possess high rate capability, pulse power<br>supply, simple working principle, high dynamics of propagation and long cycle life with low<br>cost maintenance [1]. Thus they are the best energy storage devices and extensive research<br>is being carried out around the world to develop SC material with maximum efficiency. Various<br>conducting polymers and their hybrid nanocomposites have been studied so far for electrode<br>material in SCs [2]. Among the hybrid nanocomposites, nanocomposites of conducting<br>polymers with nanoclays are promising materials for SC application as they exhibit better<br>dispersion stability, mechanical strength, good thermal, environmental properties, electrical<br>conductivity and electrochemical stability over pure conducting polymers. In this study new<br>type of nanocomposite has been synthesized using poly-o- toluidine (POT) as conducting<br>polymer and novel clay mineral identified from Tuticorin in Tamilnadu, India and named as<br>Indian clay (IC) which has properties similar to montmorillonite (MMT) [3] as the clay matrix<br>by simple, inexpensive chemical oxidative polymerization with potassium perdisulphate as the<br>oxidizing agent. The synthesized composite was studied for their structural, thermal and<br>electrochemical properties with special reference to their capacitative behaviour.<br>The structural characterization done using UV-Vis, FTIR and XRD studies showed intercalated<br>semi crystalline nature of the nanocomposites where strong interaction between the POT and<br>the IC exists. Optical band gap calculated was 2.96eV indicating the conducting nature of the<br>composite. Average crystallite size calculated from X-ray diffractogram was found to be 12nm.<br>Morphological studies performed using TEM and SAEDP confirmed the intercalated nature of<br>the composite showing the features of both the clay and the polymer. TG/ DTA and DSC<br>studies revealed the increase in polymer degradation temperature to 580.6°C in NCP2<br>compared to that of 530.6°C for pristine polymer which may be attributed to the attractive<br>coulombic interaction between the positive nitrogen of POT layer and the negatively charged<br>surface of the clay layer as a result of which clay sheet act as barrier to the degradation of<br>POT chains.<br>Electrochemical characterisation was done using cyclic voltammetry and impedance studies.<br>The voltammetric response were examined as a function of experimental parameters like pH<br>and scan rate. Optimum pH for good sensitivity response was found to be pH 1.0. The<br>synthesized NCP also shows outstanding electrochemical behavior in a broad range of scan<br>rates (50-500mV/s). With an increasing scan rate the peak current also increased thus<br>indicating good adherence of the composite onto the GC electrode surface. The well-defined<br>nature of the voltammograms at higher scan rates depicts the greater electrochemical stability<br>of the NCP. CV taken at 50mV/s (fig.1 a) exhibited well-defined redox peaks at 322.7mV and<br>3.8mV which shows that POT has retained its conducting nature though it is confined within<br>the interlayers of IC making the NCP an interesting electrode material. Specific capacitance of the composite material calculated from CV profile was found to be 280Fg-1 which is closer<br>to the literature value of 301Fg-1 for POT [4] which further proves the worth of the material as<br>a potential candidate for electrochemical capacitor. The higher value of specific capacitance<br>proves that the Bronsted-Lewis acidic sites on the surface of nanoclay can influence the<br>electron transport across the POT chains and hence can increase the specific capacitance.<br>Nyquist plot of NCP2 (fig.1.b) shows the presence of well-defined semicircle whose high<br>frequency end almost intersects the origin of the graph which is the typical impedance<br>behavior of electronically conducting polymers. The Cdl, Rct and Rs values calculated was found<br>to be 23.0 µF, 240.1ohm and 71.87ohm respectively. The low values of charge transfer<br>resistance and solution resistance indicates that the NCP is a good electrode material for<br>supercapacitor application. Bode phase plot shows a phase angle of 76° which again proves<br>the fact that this nanocomposite can be used as a supercapacitor electrode material.</p> <p><img src="https://spast.org/public/site/images/editorchief/mceclip0.png"></p> <p>The greater electrochemical stability, high specific capacitance and low charge transfer<br>resistance, greater ease of synthesis make the synthesised POT-IC NCP a promising<br>electrode material for supercapacitors.</p> R Baby Suneetha C Vedhi Copyright (c) 2021 R Baby Suneetha, C Vedhi 2021-10-17 2021-10-17 1 01 PRODUCTION OF BIODIESEL FROM WASTE FRYING OIL AS RENEWABLE SOURCE USING VANADYL PHOSPHATE AS HETEROGENEOUS CATALYST https://spast.org/techrep/article/view/2763 <p>Biodiesel has attracted great attention worldwide due to its renewability, biodegradability and better gas emission. Biodiesel from used frying oil, collected in Esmeraldas City, Ecuador, was obtained by means of heterogeneous catalytic trans-esterification, using vanadyl phosphate (VOPO<sub>4</sub>.2H<sub>2</sub>O) as catalyst. This catalyst was generated from exhausted vanadium pentoxide. The raw material, used frying oil was previously treated in order to eliminate moisture, retain suspended solids, and reduce acid index from 14 to 12%. For reducing the acidity, a cellulose filter, previously treated with a NaOH 1 % solution, was used. The exhausted catalyst, exposed to burning in microwave, calcination, and through a sonochemical method with phosphoric acid, generated vanadyl phosphate. Utilizing waste frying oil, vanadyl phosphate and methanol, a micro-reactor which supporting pressures of 2-10 atm, at 115 °C and 3 % of catalyst, was obtained biodiesel with good physic-chemical parameters. Finally, applying a multifactorial design 2<sup>2</sup>, the optimal reaction conditions were determined. Those conditions were related to the ration frying oil / methanol and reaction time. The performance of the reaction to obtain vanadyl phosphate, using a sonochemical method, is 86.38 % in 3 hours, and the optimal reaction conditions in the heterogeneous catalytic trans-esterification process are: molar ration frying oil/methanol 1:12.83 and 4.85 hours of reaction time.</p> Joseph Cruel Sigüenza Maria E. Canchingre Juan E. Tacoronte Carla Bernal Villavicencio Copyright (c) 2021 Joseph Cruel Sigüenza, Maria E. Canchingre, Juan E. Tacoronte, Carla Bernal Villavicencio 2021-10-21 2021-10-21 1 01 University timetabling optimization using FET with a sustainable and smart approach towards subgrouping process https://spast.org/techrep/article/view/1540 <p>Timetable scheduling is the most important activity in any educational institution like schools, colleges, and universities because it involves ensuring that the utilization and allocation of the resources like teachers, students, classrooms, etc. are done effectively. This ensures smooth working of the Institute and a proper administration in place. Many institutions still use manual scheduling of the timetable, which is not efficient and effective because it takes many days of planning and brainstorming to come up with an optimal or sub-optimal timetable. But with the advancement in technology, there are various software solutions that are coming up to make the process of timetable creation more efficient, and one of the software is FET (Free Evolutionary Timetabling). The authors worked towards automating the timetable management process at a university using FET and successfully reduced the scheduling time from 4 days to 1 day. Scheduling in institutions like schools is comparatively easier when compared to universities because they have fixed subjects assigned to a student group, but in universities that offer elective courses, students can select any elective out of many electives based on their interest, and so, various groups are formed based upon the electives chosen, and in this scenario scheduling the timetable is a tedious task for the management at universities. Apart from electives, there are various other constraints like batch size, rooms, regular faculty, guest lecturers, etc. and building up the timetable with so many constraints require the management to come up with a timetable after going through a lot of permutations and combinations while considering every constraint to come up with an optimal or suboptimal solution. Clashes in the constraints can be missed out while creating timetable manually which might not surface until the implementation of the timetable. Using FET software, authors were able to successfully take into considerations all the constraints while implementing the software. In the process of timetable implementation, authors also came up with a new approach of creating mutually exclusive subgroups to ensure that there was no clash among the student subgroups while assigning the teacher and subject in a particular hour, this helped in creating an optimal or sub-optimal solution. This method is found to reduce the amount of complexity in generating the timetable, and this new approach that the authors have proposed can provide a new perspective on solving the Timetable preparation issue. The authors also highlight the troubleshooting technique which would help overcome the possible errors that the FET users might come across while creating the timetable using the proposed approach. Also, in this paper, the authors discuss about the creation of a university timetable using the agile model where the timetabling solution was reached progressively through numerous iterations, where with every iteration the complexity of the constraints were increased. The other aspect of Agile methodology which was utilized was the constant collaboration with the clients, for feedback and acceptance. In addition, by implementing the FET there can be maximization use of the classroom and thus saving resources, energy, and the cost of university. The study has been done in a business school which has more than 1800 students and it offers number of management specializations with many elective courses available to the students, and these aspects makes the complexity of constraints very high as it also needs consideration of the availability of rooms, lecturers and students, but the authors were successful in taking into account the constraints and not only successfully implementing the timetable, but in the process of rolling out the timetable, the authors trained faculty &amp; administrators, and were successful in implementing a change from manual timetable creation process to FET driven automated timetable creation by imbibing some of the best practices of change management, which ensured the smooth adoption of smart and sustainable timetabling process.</p> Enoch Das Siva Muniappan S. Ushnil Dutta Justin Joy Copyright (c) 2021 Enoch Das, Siva Muniappan S., Ushnil Dutta, Justin Joy 2021-10-07 2021-10-07 1 01 Sustainability in the built environment: are we doing enough? https://spast.org/techrep/article/view/168 <p>Sustainability is one of the key requirements for any business. The ever-increasing turbulent and complex nature of the corporate environment calls for organizations to develop competitive strategic models to not only reach profits but also to meet societal and stakeholder expectations in a long-term sustainable view <a name="_ednref1"></a><a href="#_edn1">[1]</a>.</p> <p>The corporate built environment is a critical contributor to carbon emissions and one of the main reasons for depressing energy resources <a name="_ednref2"></a><a href="#_edn2">[2]</a>. Technological advancements have contributed drastically to assisting the management team to adopt sustainable practices. However, there is a knowledge gap among sustainability professionals in understanding the concept of sustainable growth and energy gap, posing as a burden for them to keep up with ongoing technological developments such as the Green Internet of Things (IoT) and the use of sensors technology.</p> <p>Addressing these challenges the aim of this research paper is to explore the current awareness level of sustainability professionals and stakeholders about corporate responsibility towards sustainability, laying the groundwork for addressing these hurdles and contributing towards the overall sustainable development. Furthermore, the researcher referred to three theories commonly used by sustainability theorists to address the above-mentioned challenges: <em>Self-determination theory </em><a name="_ednref3"></a><a href="#_edn3">[3]</a><em>,</em> <em>Stakeholder theory</em> <a name="_ednref4"></a><a href="#_edn4">[4]</a>, and <em>Sustainable leadership theory</em> <a name="_ednref5"></a><a href="#_edn5">[5]</a>.</p> <p>Qualitative methods that utilized semi-structured interview questions were used to interview sustainability professionals from the service industry. The interview guide was structured, adopting predetermined scales used by Zou et al.(2019) <a name="_ednref6"></a><a href="#_edn6">[6]</a>. The data gathered was analyzed using NVIVO12 software. Iterative method was used to code the transcripts <a name="_ednref7"></a><a href="#_edn7">[7]</a>. Under thematic analysis, a combination of both deductive approach and inductive approach was employed, this combination allows the researcher to remain coherent and consistent throughout the data's coding and analysis process <a name="_ednref8"></a><a href="#_edn8">[8]</a>.</p> <p>The researcher established five themes through thematic analysis of the data: (i) Concept of Sustainability, (ii) Corporate Sustainability Responsibility, (iii) Perception of Corporate Sustainable Responsibility, (iv) Current Tools and Concepts and, (v) Institutional Barriers and pressures in the path to sustainability. The five themes were then used as a base to formulate open-ended interview questionnaires for data collection.</p> <p>The current research paper by aligning the objectives with pre-existing theories and conducting an in-depth analysis linking the results from the survey with the objectives, themes, and theories, provides a unique insight into the current knowledge level of sustainability professionals in the corporate environment of the service industry. The survey results reflect an increased need for training and knowledge sharing among business leaders when it comes to the environmental impacts of the business, developing nations need to shift focus from the social aspect of Corporate Social Responsibility to Corporate Sustainable Responsibility.</p> <p>With the rapid change in climate and rising global warming conditions, more research must be conducted in order to investigate and track the causes of carbon emissions and sources of energy depression. This research contributes to the vast array of existing green knowledge with a special focus on the corporate built environment and green manageability.</p> <p>Recalling the urgent need for sustainability, this research paper illustrates the current awareness of sustainability professionals concerning corporate sustainable responsibility through three objectives:</p> <p>To identify the different barriers that influence corporate executives, management teams, and the organization as a whole from attaining sustainability.</p> <p>To analyze crucial strategic decisions that impact CO2 emissions and the firms' energy consumption in the built environment.</p> <p>To formulate a relationship between sustainability and industry 4.0 improving green growth in the built environment.</p> <p>In the past only Governments were held responsible for ensuring sustainable growth and development, however, with rapid industrial developments came more complex environmental issues which called for the cooperation of not only corporates from different industries but also all stakeholders in the society. The current research addresses issues that arise in the corporate environment allowing the readers to examine and understand the relationship between energy systems used in the built environment and their impacts on society.</p> <p>It is important for both internal and external stakeholders to understand in simple language the effects of the business operations on the five Ps in relation to the Sustainable Development Goals: People, Planet, Peace, Prosperity, and Partnering. Given that there exists a knowledge gap amongst stakeholders and shareholders in corporate environment, the findings presented in this research paper will appeal to the scientific audience and also research scholars in educational institutions who are major change catalysts when it comes to sustainability.</p> Varynia Wankhar Leena Fukey Sahana Reddy Copyright (c) 2021 Varynia Wankhar, Dr Leena Fukey, Sahana Reddy 2021-09-02 2021-09-02 1 01 A Qualitative study on the Influence of Social Media Marketing Campaigns on consumer purchase https://spast.org/techrep/article/view/209 <p>People now spend most of their time using social networking applications on their phones, thanks to technological advances. There's no doubt that advertising campaigns on various products and services via social media is a better approach to obtain consumers' positive buy intentions. This leads to an increase in sales owing to customers' positive purchase intentions in today's modern environment. Customers should be able to connect with one other on the companies' platforms, according to previous surveys (Rowley, 2004).</p> <p>Everyone is connected to the internet in today's digitalized society, and it's not just the young. Advertising via social applications and the internet is therefore an option for advertisers. To acquire a product or service, a consumer must first form an opinion about that product or service. Until smart phones hit the general market, social media marketing was done via SMS, and several studies have shown that people are eager to be promoted to through their social network phones. It is true that patterns have completely altered throughout time. However, depending on the advertising channel, promotional methods and advertising might influence customer perception and buy intention (Elliott &amp; Speck, 1998).</p> <p>Customer motivation and perception are taken as variables as it plays a key role in influencing consumer purchase decisions. As a result, companies would be able to learn more about how consumers view their brand or product. Advertisers and customers alike profit from the comments and posts of others on social media as an advertising medium (Cha, 2009). Firms often take their lead from social media sites like Facebook that allow internet users to form virtual relationships with one other so they may benefit from their likes and comments on various postings (Andriole, 2010). Users can conduct a variety of functions with social networking applications, including finding, accessing, and sharing information, bill payment, navigation, and shopping. For this reason, several firms have built their own smart phone applications for communicating with clients and advertising their products (Kim, Wang &amp; Malthouse 2015). Intention to purchase may be described as a customer's belief that he or she will acquire a certain product and/or service Numerous elements (internal and/or external) can influence a customer's decision to buy. Apps platforms and social media advertising have the potential to affect consumer views and motivations, therefore influencing their buying intentions.</p> <p>This study aims to examine the influence of social media marketing campaigns on customers' purchase intentions. The target audience (which includes both men and women) who rely heavily on smart phones and social media sites such as Facebook etc. The primary would be collected by interview process for the study. It focuses on the influence of social media marketing campaigns while studying the relationship between consumer perception, motivation, and purchase intention.</p> Siddharth Nanda Dr. Sangeeta Jauhari Dr. Kaushik Mishra Copyright (c) 2021 Siddharth Nanda, Dr. Sangeeta Johri, Dr. Kaushik Mishra 2021-09-08 2021-09-08 1 01 Administrative Staff – Exploring the Potential Human Resourc