Transition Metal Oxide/Graphene/Reduced Graphene Oxide Composites as Electrode Materials for Supercapacitors

Abstract

Graphene-based materials have been extensively used as electrode materials for supercapacitor applications due to their extraordinarily high electrical conductivity and large surface area. However, they suffer from the low energy density and specific capacitance because of the graphene’s propensity toward aggregation and restacking, which reducing the ion-accessible surfaces and limiting ion and electron transport. Therefore, to enhance electrochemical performance for high-performance supercapacitor, pseudocapacitive transition metal oxides are integrated with graphene-based materials. Currently, these hybrid supercapacitors have been attracted much attention due to the combination of rapid charge–discharge and long cycle life for energy storage in modern electronic devices. In these hybrid materials, the emphasis is given to synergistic effects between graphene/reduced graphene oxide and metal oxides, which results in high energy and power densities along with high specific capacitance. This chapter is mainly focused on hybrid supercapacitors of transition metal oxides with graphene-based materials. The chapter provides decent and updated coverage on the synthesis, structure, properties, and supercapacitor performance of graphene and transition metal oxide-based composite materials.