REDUCED GRAPHENE OXIDE COMPOSITES FOR ENERGY GENERATION AND STORAGE

摘要

Energy storage systems are playing important roles in storing energy generated from sun and wind, or other renewable energy sources. Electrical energy storage systems include conventional capacitors, batteries, and electrochemical capacitors or supercapacitors. Supercapacitors are the primary choice for the applications where faster- and higher-power energy storage systems are needed because they have higher energy density than conventional capacitors, and higher power density and faster power delivery than batteries.Graphene and its derivatives, have also been studied as potential candidates for supercapacitor electrodes due to their high specific surface area (2675m~2/g), chemical stability, excellent electrical, thermal conductivity and capacitance and low cost. Since the surface area of graphene sheet play a significant role which directly affects the performance of the supercapacitors, it is important to disperse graphene and its derivatives to reduce the agglomeration and restacking due to Van Der Waals attraction between the neighboring sheets. The aggregation reduces the effective surface area resulting loss of capacitance. A few researchers have made effort to keep graphene sheets separated by addition of metal oxide nanoparticles. Metal oxide nanocomposites with graphene have been explored for superior capacitance. The approach utilizing nanoparticles to improve the electrochemical performance is an indication of a positive synergistic effect of graphene sheets and nanoparticles. '