Analysis of Electrochemical Performance of Reduced Graphene Oxide based Symmetric Supercapacitor with different Aqueous Electrolytes

Carbon nanomaterials are considered to be the materials of choice for the fabrication of electrochemical energy storage devices due to their stability, cost-effectiveness, well-established processing techniques, and superior performance compared to other active materials. In the present work, reduced graphene oxide (rGO) has been synthesized and used for the fabrication of a symmetric supercapacitor. The electrochemical performance of the fabricated supercapacitors with three different aqueous electrolytes namely 0.5 M H2SO4, 0.5 M H3PO4, and 1.0M Na2SO4 have been compared and analyzed. Among the three electrolytes, the highest areal specific capacitance of 14 mF/cm(2) was calculated at a scan rate of 5 mV/s observed with 0.5M H3PO4 electrolyte. The results were also confirmed from the charge/discharge results where the supercapacitor with 0.5M H3PO4 electrolyte delivered a specific capacitance of 11 mF/cm(2) at a current density of 0.16 mA/cm(2). In order to assess the stability of the supercapacitor with different electrolytes, the cells were subjected to continuous charge/discharge cycling and it was observed that acidic electrolytes showed excellent cyclic stability with no appreciable drop in specific capacitance as compared to the neutral electrolyte.