INFLUENCE OF METAL ION ON STRUCTURE AND CAPACITANCE PERFORMANCES OF MANGANESE OXIDE/CARBON MATERIALS FOR SUPERCAPACITORS

摘要

A composite of manganese oxide /carbon powders for supercapacitors was prepared by a redox of acidic KMnO_4 and active carbon(AC) in this paper, and Ni~(2+)、Co~(2+) 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 Ni~(2+)and Co~(2+). 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 Ni~(2+)and Co~(2+) ions.