Co3O4 thin film prepared by a chemical bath deposition for electrochemical capacitors

Co3O4 thin film is synthesized on ITO by a chemical bath deposition. The prepared Co3O4 thin film is characterized by X-ray diffraction, and scanning electron microscopy. Electrochemical capacitive behavior of synthesized Co3O4 thin film is investigated by cyclic voltammetry, constant current charge/discharge and electrochemical impedance spectroscopy. Scanning electron microscopy images show that Co3O4 thin film is composed of spherical-like coarse particles, together with some pores among particles. Electrochemical studies reveal that capacitive characteristic of Co3O4 thin film mainly results from pseudocapacitance. Co3O4 thin film exhibits a maximum specific capacitance of 227 F g−1 at the specific current of 0.2 A g−1. The specific capacitance reduces to 152 F g−1 when the specific current increases to 1.4 A g−1. The specific capacitance retention ratio is 67% at the specific current range from 0.2 to 1.4 A g−1.