Technological Development of Graphene and Graphene Nanocomposite-Based Supercapacitor Electrode

Abstract

Graphene and graphene-based nanomaterials are captivating immense attention nowadays due to their novel properties, like highly stretchable specific surface area, phenomenal electrical conductivity, high transparency, remarkable chemical stability, and brilliant mechanical behavior. Utilizing these remarkable properties, graphene acts as a prominent nanomaterial for supercapacitor electrodes and various energy storage devices. Moreover, its admirable mechanical properties with immense tensile strength, Young’s modulus and stretching capability (elasticity) make it greatly applicable electrode materials to fabricate ultrathin, flexible, safe energy storage devices in wearable and handy electronic products, biointegrated devices, recreational sports gadgets, medical utensils, telecommunication, automobile, space satellites, and hybrid electric vehicles. Here, we have emphasized on the recent developments of graphene and various modified graphene-based nanocomposites as a promising electrode material for supercapacitor applications depending 264on the various nanostructures formed by various synthesis techniques, to improve the specific capacitance, voltage window, cyclic stability, charging/discharging time, electrical conductivity, and specific energy and power density. But in the last few decades, researchers devoted themselves to formulate a graphene and/or its derivatives-based supercapacitors with high gravimetric energy density while retaining the intrinsic properties of high specific power density and long shelf life. Extensive research is going on for development of various graphene-based materials, improvization of their compositions and dimensions at varying scale using effective, low-cost synthesis techniques with enhanced electrochemical properties. In this review, classification of supercapacitors are studied based on their charge storage phenomenon (electrostatic or non-Faradaic, Faradaic, or combination of two) as well as functional active electrode materials (symmetric and asymmetric) and the latest development and perspective of graphene or graphene-based materials as supercapacitor electrodes have been critically analyzed.