Optimization of Experimental Conditions in Preparation of Manganese Oxide Electrodes for Electrochemical Capacitors

Abstract

To improve the performance of manganese oxides applying to electrochemical capacitor as electrodes, the hydrothermal electrochemical deposition method was used for preparing the manganese oxide films. The optimum synthesis conditions and each synthesis factor (such as solution concentration, synthesis temperature, deposition time and deposition voltage) contributing to the specific capacitance of synthesized manganese oxides were approached by using Taguchi experimental design method. The synthesis temperature and concentration of manganese acetate were the two main factors influencing the specific capacitance. The manganese oxide films deposited under the solution concentration of 0.2 mol L^-1, synthesis temperature of 100°C, deposition time of 60 s, and deposition voltage of 0.8 V showed the optimum specific capacitance of ca. 126.35 Fg^-1. Porous and needle-like morphology enhanced the specific capacitance of manganese oxide film but restricted the stability performance of charge/discharge. The crystalline Mn₃O₄ and denser morphology revealed the good stable ability of capacitive performance after 600 cyclic-life test.