Microwave-Induced Structural Modifications in Reduced Graphene Oxide for Enhanced Supercapacitive Performance

Abstract

The state of the art in improving the thermal and electrochemical properties of reduced graphene oxide (RGO) prepared via microwave heat treatment (MWHT)-induced chemical reduction of modified Hummer's method synthesized GO is presented. Microwave heating is an efficient and green method of heating. It is a facile and mild heating method through which uniform and synchronized heating can be done. Thus, it helps in enhancing the uniform porosity throughout the graphene matrix. The optical, structural, and thermal characterization of synthesized RGO and after microwave heat treatment (MWRGO) have been done using UV–Visible absorption spectroscopy, Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, and Thermogravimetric Analysis (TGA). The prepared materials were tested for supercapacitor (SC) in a symmetric electric double layer capacitor (EDLC) type parallel plate cell design. The prepared cell has been checked for electrochemical performance using cyclic voltammetry (CV) measurements and cross-confirmed through Electrochemical Impedance spectroscopy (EIS) and Galvanostatic Charge–discharge (GCD) measurements. Enhanced electrochemical performance of MWRGO-based supercapacitive cell depicts specific capacitance of 289 F/g at low ESR of 3.4 Ω and energy density of 24 Wh/Kg at power density of 1000 W/Kg. This is due to enhanced specific surface area to 731.81 m²/g after microwave heat treatment, which hence plays a major role in achieving virtuous electrochemical performance of RGO for energy applications.