Physicochemical properties and electrochemical behavior of binary manganese-cobalt oxide electrodes for supercapacitor applications

Binary Mn-Co oxide electrodes were prepared by anodic deposition at 25 degrees C in a mixture of manganese acetate and cobalt acetate aqueous solutions. It was found that the Mn-to-Co content ratio in the oxide could be easily controlled by adjusting the composition of the plating solution. The chemical states of the oxides produced were analyzed using an X-ray photoelectron spectroscope, and the deposition mechanism was thus explored in this study. Chronopotentiometry was also performed to evaluate the pseudocapacitive characteristics of the oxide electrodes. The experimental results indicated that an appropriate amount of Co addition could effectively inhibit the anodic dissolution of Mn and consequently improve the electrochemical reversibility and stability of the oxide electrode. However, it was also confirmed that high Co content caused a significant reduction in the specific capacitance of the oxide. (C) 2007 Elsevier B.V. All rights reserved.