Graphene as the electrode material in supercapacitors

Abstract

Supercapacitors, a new energy storage element based on electrochemical double layer capacitance, store energy by ion adsorption, have recently attracted increasing interest with the sharp development of nanostructure materials. Supercapacitors store and release energy by nanoscopic charge separation at the interface between an electrode and an electrolyte, and the energy restored in it is inversely proportional to the thickness of the double layer. Due to its high power density, long cycle life, low weight, flexible packaging and a wide thermal operating range compared to other conventional energy storage devices, supercapacitor can be used as a potential energy device bridging the gap between chemical power and common electrostatic capacitance. However, a distinct defect for supercapacitor is the energy density lower than rechargeable batteries. Electrode material is the key to improve the performance of supercapacitor, so most of researches current is around searching electrode materials with higher specific capacitance. Fortunately, graphene as a single atomic of graphite was found to be suitable for electrode materials in supercapacitors owing to its super conductivity and high specific area. In this paper, we report a study on graphene as the electrode material in supercapacitor.