Design and development of electrode materials for hybrid supercapacitors

Abstract

The synergy between energy and the environment is highly essential for the survival of the human race. However, extensive exploitation of fossil fuels has resulted in widespread environmental damage. The glacier burst/cloud burst at Uttarakhand, India, on 7th February 2021 is a classic example that exposes the extent of catastrophes caused due to climate change. A paradigm shift in the dependence from non-renewable to renewable energy sources is the need of the hour to mitigate these effects. newlineIn the current scenario, 80 % of energy comes from fossil fuels in India. The transport sector alone accounts for 18 % of the total energy consumption. Combustion of the fuels in automobiles releases greenhouse gases into the environment, worsening the climatic deterioration. At this juncture, green technologies like electric vehicles have become important. On the other hand, vehicles operating on renewable energy generation technologies need a constant and stable power supply. Energy can be effectively stored electrochemically by batteries and supercapacitors. newlineIn comparison to batteries, supercapacitors can be charged and discharged at a faster rate. The life cycle achievable in the case of supercapacitors is over a million cycles compared to around 500 cycles for batteries. Owing to these features, research into supercapacitors will yield rich dividends in terms of devices possessing superior electrochemical characteristics. newlineThe supercapacitor research has witnessed a broad range of materials such as metal compounds, carbonaceous materials and their composites as electrode materials. Transition metals like nickel, cobalt and manganese are widely researched for energy storage due to their excellent redox kinetics. Still, they are often limited by their conductivity, stability and slower diffusion rates.