Effects of Addition of Graphene Oxide on Energy Density of Supercapacitor

Abstract

Supercapacitor (SC) is a device designed for storing energy by using a large surface area of conducting material. SC consists of an electrolyte, a separator and a pair of polarizable electrodes. It has been used in storage applications such as hybrid vehicles, memory protection, electronic devices, etc. Based on the storage mechanism of an SC, it can be categorized into pseudocapacitor and electric double-layer capacitors. SCs have long cycles, large power density, and rapid charging speed; however, its major drawback is low energy density, which is attributed to the intrinsic nature of the electroactive material used as electrodes in SCs. The low energy density can be improved upon by effective control of material pores size and specific surface area as well as expanding the operation voltage window. It is expected that addition of graphene oxide in SC material can reinforce their electrochemical performance notably the energy density. The GOs are the integral members in the graphene–graphite family, with excellent mechanical and optical properties that are tunable. In addition, GO has a larger surface area and is cost effective. The basic concepts discussed in this chapter are the working principle of an SC, techniques deployed in the synthesis of GO, and structure and properties of GO. Moreover, the influence of GO on the energy density of an SC electrode material is also discussed. These include the modification or tuning of SC electrode materials such as metal oxides, conducting polymers and carbons by addition of GO to improve their energy density.