Chapter 5 - Supercapacitors based on graphene and its hybrids

Abstract

The fascinating properties of graphene, like high theoretical surface area, better electrical/thermal conductivity, excellent mechanical behavior, and chemical inertness, make it a suitable material for energy storage applications, specifically for supercapacitor. The pristine graphene-based materials store charge forming a double layer at the electrode/electrolyte interface and show many fold higher power density, but lag behind the traditional batteries in terms of energy density, thereby limiting their broad application. Therefore strategies have been developed and hybrids of graphene with other carbon nanostructures (like activated carbon, carbon nanotube, carbon black, etc.) and transition metal oxides/hydroxides etc. have been prepared to demonstrate their charge storage performances. The hybridization process avails the synergistic properties of each of the constituents, boosting the specific energy without compromising the cycle life of the assembled supercapacitor device. This chapter presents a brief discussion on the classification of supercapacitors, based on the types of electrode materials, electrolytes, and cell assembly, emphasizing the synthesis of various graphene hybrids and their charge storage performances. Keeping in mind the current requirements, the use of these hybrid materials for the fabrication of flexible electrodes and solid-state supercapacitor devices is discussed. We presume that this chapter will attract broad readers of material research as well as professionals working in the field of energy research across the globe.