Electrochemical and Capacitance Properties of Rod-Shaped MnO[sub 2] for Supercapacitor

A novel kind of electrode material, rod-shaped , was synthesized under high viscosity for the first time. The was proved to be the multicrystal with the mixture of α- and by X-ray diffraction. From transmission electron micoscopy, it could be seen that the sample has a length of and a diameter of . The ratio of length to diameter could reach more than 20:1. The electrochemical properties were examined by cyclic voltammograms (CV), galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS) in three electrode cell. According to CV results, aqueous solution was a proper electrolyte for supercapacitors. A maximum specific capacitance (SC) of was obtained from galvanostatic charge/discharge curve in solution at constant current of 10 mA. The SC value was at a high current of 50 mA which exhibit high power characteristics of the rod-shaped . The electrolyte resistance was by researching on EIS. Long cycle-life and high coulombic efficiency of rod-shaped were also demonstrated by charging and discharging 1000 cycles.