Influence of metal ion on structure and capacitance performances of manganese oxide/carbon materials for supercapacitors

A composite of manganese oxide /carbon powders for supercapacitors was prepared by a redox of acidic KMnO₄ and active carbon(AC) in this paper, and Ni²⁺, Co²⁺ ions were added during the preparation .The influence of AC specific surface area and metal ions on structure and electrochemical properties of obtained manganese oxide /carbon powders were investigated. The crystal structure and surface morphology of manganese oxide /carbon powders were examined by X-ray diffraction(XRD) , X-ray photoelectron spectroscopy(XPS) and scanning electron microscope. Cyclic voltammetry(CV) and electrochemical impedance were performed to evaluate the electrochemical properties of obtained manganese oxide /carbon powders. The XRD result indicated that the obtained manganese oxide had poor crystallinity, and the crystal structure of manganese oxide was changed after the composite doped with Ni²⁺and Co²⁺. The results of CV showed that obtained manganese oxide /carbon powders possess the ideal capacitive property, and the specific capacitance reached to 185F/g after doping Ni²⁺and Co ²⁺ ions.