Characterization of manganese dioxide electrodeposited by pulse and direct current for electrochemical capacitor

This paper describes the electrochemical capacitor behavior of manganese dioxide (MD, MnO(2)) samples that were prepared by direct current (DCMD) and pulse current (PCMD) electrodeposition. The capacitive characteristics of the samples were studied in 0.5 M aqueous Na(2)SO(4) solution using the cyclic voltammetry (CV) method. Scanning electron microscopy (SEM). X-ray diffraction (XRD), chemical composition analyses and the Barrett-Joyner-Halenda (BJH) method were employed to characterize the samples. In the study of the effect of scan rate on capacitance, it was revealed that PCMD displayed higher capacities than DCMD for all scan rates. The higher capacitive performance of PCMD was attributed to its porosity (specific surface area, pore volume, and pore-size distribution), chemical composition and structural properties. (C) 2009 Elsevier B.V. All rights reserved.