209 p.The electrochemical capacitors or supercapacitors are envisioned as potential next-generation energy storage systems because of their excellent storage capacity, power density, and long-term durability. However, all these advantages are overshadowed by their poor energy density. Thus, this thesis aims to achieve a high-energy supercapacitor device without compromising its power performance to make them more commercially viable for many applications. The research work is associated with the improvement of the supercapacitors in different device configurations, such as EDL, asymmetric, and hybrid LIC systems by integration of advanced material and cell design. The results obtained from the studies of different supercapacitor systems demonstrate that the variation in electrode mass, cell voltage, and electrolyte has a huge impact on the overall electrochemical performance, stability, life expectancy, and safety of the device. Therefore, careful optimization of cell design and advancement in electrode materials retains the high importance driving factors of the supercapacitors for the development of future energy storage technology
