Enhanced Capacitance of Thermally Reduced Hexagonal Graphene Oxide for High Performance Supercapacitor

An easy method, cost effective, and scalable approach was developed for the preparation of graphene nanosheets. Graphene oxide (GO) was synthesized by modified Hummer method, and thermal reduction was performed in air ambient at 350 degrees C. The results of Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD) spectroscopy indicate that GO is reduced to graphene. A perfect hexagonal GO structure was confirmed by high resolution transmission electron microscope (HRTEM) images. After thermal reduction, few layers of thermally reduced graphene oxide (TRGO) with dimension of hundred nanometers were obtained. The electrochemical properties of the graphene nanosheets as electrode materials for supercapacitors were studied by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Higher specific capacitance of 731 F g(-1) in 1M H2SO4 at a scan rate of 10 mV s(-1), and a large specific capacitance of 451 F g(-1) was preserved at high scan rate of 100 mV s(-1).