Enhancement of Electrochemical Capacitance by Doping Rod-Like Mn Oxide Electrodes with Co

Abstract

The electrochemical properties of nanocrystalline Mn oxide and Mn-Co doped oxide electrodes, with and without a conducting polymer (PEDOT) coating, were investigated to determine the effect of morphology, chemistry and crystal structure on the corresponding electrochemical behavior of synthesized electrodes. Mn-Co oxide electrodes with rod-like structures were synthesized electrochemically by anodic deposition from an electrolyte solution of Mn acetate and Co sulfate on Au coated Si substrates. The electrochemical behavior of the deposits was studied by cyclic voltammetry at different scan rates. Also, microstructural characterization of as-deposited and cycled electrodes was conducted using SEM. The Mn-Co oxide/PEDOT electrodes showed improved specific capacity and electrochemical cyclability relative to uncoated Mn oxide, Mn-Co oxide and Mn oxide/PEDOT electrodes. A specific capacitance of ~310 Fg−1, with a capacitance retention of 92% of the original value, was obtained for Mn-Co/PEDOT electrodes after 250 cycles in 0.5M Na2SO4 at 100 mVs−1.