Faculty Publications
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Item Fabrication and performance evaluation of hybrid supercapacitor electrodes based on carbon nanotubes and sputtered TiO2(Institute of Physics Publishing michael.roberts@iop.org, 2016) Aravinda, L.S.; Nagaraja, K.K.; Nagaraja, H.S.; Bhat, K.U.; Badekai Ramachandra, B.R.We report a simple and eco-friendly method for the fabrication of a titanium dioxide/functionalized multiwalled carbon nanotube (TiO2/FMWCNT) composite electrode for use in supercapacitors. The nanocomposite electrodes were formed by depositing titanium dioxide onto FMWCNTs using reactive magnetron sputtering, thus providing a green roue for the formation of the binder-free composite electrode. It is shown that the electrochemical performance of the fabricated electrodes can be altered by tuning the thickness of the titanium dioxide overlayer. The integrated nanocomposite electrode showed an improved specific capacitance of 90 Fg-1 in two-electrode configuration. © 2016 IOP Publishing Ltd.Item Performance of an activated carbon supercapacitor electrode synthesised from waste Compact Discs (CDs)(Korean Society of Industrial Engineering Chemistry A-803 Twin Bldg 275-3 Yangjae-Dong Seocho-Kul Seoul 137-130, 2018) Farzana, R.; Rajarao, R.; Badekai Ramachandra, B.R.; Sahajwalla, V.Microporous activated carbon was synthesised using waste compact discs as precursor through physical activation method for supercapacitor electrode application. The activated carbon prepared at 900 °C for a time interval of 8 h showed highest surface area of 1214.25 m2 g?1. The electrochemical measurements showed that waste CDs derived activated carbon exhibited good specific capacitance, cycle stability and good rate capability compared to other waste derived activated carbon. The specific capacitance 51 F g?1 at the current density of 10 mV s?1 and energy density of 21.43 Wh kg?1 at power density 0.7 kW kg?1 was achieved in non-aqueous electrolyte. © 2018 The Korean Society of Industrial and Engineering ChemistryItem Enhancing supercapacitor performance with zinc doped MnSe nanomaterial(Springer, 2024) Mascarenhas, F.J.; Badekai Ramachandra, B.R.The decreasing availability of fossil fuels and the increasing demand for energy highlight the pressing need for sustainable energy sources. Electrochemical technologies, notably supercapacitors, play a key role. They promise renewable energy storage, necessitating high-performing, safe, and affordable electrode materials. In this study, we present a novel hydrothermal synthesis method for producing MnSe and ZnxMn1-xSe materials across a range of concentrations (x = 0.01, 0.02, and 0.03). Characterization techniques including XRD, FESEM, HRTEM, BET and Raman analysis were employed. Among the synthesized compositions, Zn0.03Mn0.97Se emerged as the most promising material for supercapacitor applications. Evaluation through cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) revealed specific capacitance values of 135 F/g at 3 mV/s and 95 F/g at 0.5 A/g for Zn0.03Mn0.97Se. Furthermore, the material demonstrated impressive stability, retaining 97% of its capacitance after 1000 cycles. Additionally, to validate the potential of the synthesized electrode, we assembled a two-electrode symmetric cell using Zn0.03Mn0.97Se as both positive and negative electrode material in a 5 M KOH electrolyte. Extensive characterization techniques, including CV, GCD, and long-term cyclic stability tests, revealed compelling evidence of the material’s robust electrochemical behavior. These findings underscore the potential of Zn0.03Mn0.97Se for supercapacitors, contributing to the advancement of sustainable energy storage. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.Item Impact of electrolyte concentration on electrochemical performance of Cocos nucifera Waste-Derived High-Surface carbon for green energy storage(Elsevier Ltd, 2024) Hegde, S.S.; Badekai Ramachandra, B.R.The increasing popularity of utilizing biomass's natural structure represents a promising avenue for sustainable innovation, as it taps into the inherent characteristics of organic materials to address various environmental and industrial challenges. Researchers and industries continue to explore the full potential of biomass in creating more sustainable and efficient solutions. The transformation of biomass into carbon materials is an indirect means of utilizing CO2 as a carbon source, thus contributing to the sustainable development of energy storage technologies and also in pollution reduction. In the quest for sustainable energy solutions, this research unveils a cost-effective approach to supercapacitor development by harnessing the untapped potential of Cocos nucifera trunk sawdust-derived high-surface carbon (CHSC). Through a meticulous process involving ZnCl2 treatment and KOH activation at varying temperatures, CHSC-700 emerges as a standout electrode material with exceptional structural characteristics, boasting enhanced graphitization and a specific surface area of 1153.72 m2/g. Further, the study delved into the nuanced relationship between electrolyte concentration and supercapacitor performance, pinpointing 6 M KOH as the optimal condition. In 6 M KOH, the electrode exhibits a maximum specific capacitance of 559.27F/g at the current density of 0.5 A/g with outstanding cyclic stability, retaining 80.37 % capacitance after 20,000 cycles and an impressive energy density of 18.92 Wh/kg and power density of 246.75 W/kg. This systematic exploration provides valuable data for understanding the biomass-derived carbon electrode's behaviour under various electrolyte concentrations, offering crucial information for optimizing its performance in practical applications, such as energy storage devices. © 2024 Elsevier LtdItem Recycling waste plastics and biowaste into high-performance NiCo-MOF/activated carbon electrocatalyst for overall water splitting(Elsevier Ltd, 2025) Nayak, M.P.; Rao, L.; Rodney, J.D.; S, S.; Rohit, A.G.; Badekai Ramachandra, B.R.Environmental and energy crises are the most significant global challenges. Developing non-precious and environmentally sustainable electrocatalysts remains critical for advancing renewable hydrogen production. This study presents a novel hybrid electrocatalyst comprising a NiCo-BDC Metal-Organic Framework (NiCo-MOF), where the BDC (Benzene 1,4-di carboxylic acid) ligand was obtained by recycling waste poly(ethylene terephthalate) (PET) bottles, integrated with activated carbon (AC) derived from dried drumstick (Moringa olifera) biowaste, via a one-pot hydrothermal method. The research emphasizes optimizing the AC content within the MOF matrix to enhance catalytic performance. The synergistic interaction between NiCo-MOF and AC significantly reduces the overpotentials required for the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) in an alkaline medium. Notably, the optimized composite, NiCo-MOF@40AC, exhibited enhanced crystallinity, BET surface area, and electrocatalytic activity. At a current density of 100 mA cm?2, NiCo-MOF@40AC achieved overpotentials as low as 217 mV for HER with a Tafel slope of 105.6 mV dec?1 and 315 mV for OER with a Tafel slope of 42.2 mV dec?1. Furthermore, this material demonstrated robust stability over a 24 h chrono potentiometric test, maintaining performance at an elevated current density of 200 mA cm?2. In a two-electrode system, NiCo-MOF@40AC needed only 1.58 V to sustain a current density of 10 mA cm?2, exhibiting stability over 48 h and 24 h at a current density of 10 mA cm?2 and 400 mA cm?2, respectively. An average faradaic efficiency was found to be 93.48 % for HER and 91.91 % for OER. These findings highlight the potential of NiCo-MOF@40AC as an efficient electrocatalyst, characterized by a high surface area, rapid electron transfer, favorable structural properties, and enhanced reaction kinetics. © 2025 Hydrogen Energy Publications LLC