Various metal oxide nanostructures of RuO2, MnO2, NiO, Co3O4, SnO2, MoO3, and V2O5 have been used widely as promising electrode materials for supercapacitor applications. Among these Cobalt oxide (Co3O4) is believed to be one of the best materials among transition metal oxides for supercapacitors owing to its high theoretical capacitance (3560 Fg-1), environmental friendliness, and better electrochemical performance. On the other hand, MnO2 is one of the most favorable pseudo-capacitor electrode materials because of its low cost, environmentally friendly characteristics, and excellent capacitive performance. The intrinsically low conductivity of MnO2, however, limits its practical applications as a pseudo-capacitive material. Several strategies have been employed to improve the electrical conductivity of MnO2 based electrode. One simple strategy is to combine MnO2 with other metal oxides to form hybrid nanostructure with sufficient electrical conductivity. Another approach is to integrate it with electrically conducting materials like carbon materials or graphene to enhance the electrochemical stability and electric conductivity of the electrode.
In the present study, we developed new Co3O4- MnO2-graphene oxide-based electrode by simple hydrothermal technique. The synthesized electrode materials are characterized by, XRD, XPS, FE-SEM, TEM, HRTEM etc. The supercapacitor performance of all the prepared electrodes was assessed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge measurements. The important parameters of electrochemical supercapacitor like specific capacitance, energy density and electrochemical stability are measured in this work.