Electrochemical capacitance characteristics of corn-like MnO2 prepared by pulse electrodeposition

Abstract

Corn-like MnO2 electrodes with promising capacitive behavior have been prepared successfully by pulse electrodeposition. Effects of duty ratio and electrodeposition time on the performance of MnO2 electrodes were investigated. The crystal structure and morphology of the obtained material were fully characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that the structure of the obtained MnO2 was amorphous, and that the morphology of the sample exhibited a porous corn-like characteristic. Moreover, the electrochemical properties of the as-prepared MnO2 as an electrode material for supercapacitor were characterized and analyzed by cyclic voltammetry measurements in 1mol/L neutral Na2SO4 aqueous electrolyte. The optimal pulse electrodeposition conditions were obtained as follows: MnSO4 0.2mol/L, Na2SO4 0.15mol/L, electrodeposition temperature 20°C, pulse period 1min, duty ratio 0.2 and the electrodeposition time 204min. Under these optimum conditions, the sample exhibits the high specific capacitance of 0.278F/cm2 at a 5mV/s scan rate. The good capacitive performance and the simple accessibility make this corn-like MnO2 a promising candidate as a supercapacitor electrode material.