Methyl-orange/reduced graphene oxide composite as the electrode material for the solid-state supercapacitor

Abstract Herein, we have introduced the electrode material made up of a composite of an electrochemical active organic molecule (i.e. methyl orange (MO)) and reduced graphene oxide (rGO) composite. This composite is found to be a potential material for supercapacitor application due to the sustainability, redox reversibility of organic molecules, and good conductivity of rGO. For fabricating symmetric solid-state cell (MO/rGO//PVA/H2SO4//MO/rGO), polyvinyl alcohol–sulphuric acid (PVA/H2SO4) aqueous gel polymer electrolyte (GPE) has been sandwiched between the two MO/rGO electrodes. It was found that a MO/rGO based symmetric cell interfaced with a PVA/H2SO4 gel electrolyte has a specific capacitance of 166.79 F g−1 and an energy density of 11.58 Wh kg−1 at a power density of 6.25 kW kg−1. Here, good specific capacitance is the result of a combination of both electric double-layer capacitor (EDLC) and pseudo-capacitive behaviour observed in a fabricated cell. The specific capacitance is stable after 2500 cycles of charge and discharge, with an initial fade of 32 %. This synthesized material and fabricated device found its potential to be used for the supercapacitor application.