Electrochemical Analysis of Graphene Oxide and Reduced Graphene Oxide for Super Capacitor Applications

摘要

Graphene Oxide (GO) was successfully synthesized by following the Hummer's method and was reduced to form reduced Graphene Oxide (rGO) by using Zn metal powder. The AFM image showed smooth surface for both GO and rGO, indicating the formation of GO sheets. The reduction in lattice spacing from 0.85 to 0.36 nm in rGO is caused by the removal of the oxygen-containing functional groups bonded on the surface of the graphene layers. The defect density as well as the number of stacking in rGO is reduced as compared to GO indicated by the reduction of both I_D/I_G and I_2D/I_G ratio. As shown by the CV measurement the integrated area under the CV curve was increased with a rectangular shape for rGO and hence obtained better capacitance than GO. Hence, rGO has a better super capacitor property than GO. The impedance spectroscopy showed that the value of RCT is 21.84 and 30.54 ohm for rGO and GO respectively, indicating an increase in the charge transfer resistance for GO, and hence increased charge conductivity for rGO.