Microstructural characterization of Mn oxide/PEDOT electrodes with rod-like structures for application as electrochemical capacitors

Mn oxide/PEDOT coaxial core/shell electrodes were electrochemically synthesized without any catalysts or templates using a stepwise synthetic approach. Mn oxide (1-1.5 mu m diameter) rods were first synthesized by anodic deposition from a 0.01M Mn acetate solution, then coated electrochemically with a conducting polymer (PEDOT). The morphology of the electrodes depended on the pH of the electrolyte, deposition potential, current density and polymer deposition time, which affect the electrochemical behavior of the capacitor. The capacitive properties of the deposits were investigated in terms of morphological and structural evolution by characterization using scanning electron microscopy (SEM). The Mn oxide/PEDOT electrodes showed significantly improved specific capacity and charge/discharge stability relative to uncoated Mn oxide electrodes with rod-like structures. The best specific capacitance for Mn oxide/PEDOT coaxial rods produced sequentially was remarkably high (similar to 285 Fg(-1)). Also, after 250 cycles in 0.5M Na2SO4 at 20 mVs(-1), specific capacitance retention was 92% of the original value.