Preparation and electrochemical property of MnO₂/carbon microsphere composite

The MnO₂/CMSs composite was obtained by coating MnO₂ onto the surface of carbon microspheres (CMSs), which were prepared by chemical vapor deposition and oxidized by a mixture of 0.1 mol/L KMnO₄ and 0.1 mol/L HNO₃. And then MnO₂/CMSs composite was washed by H₂C₂O₄ to obtain oxidized-CMSs. The morphology and structure of all samples were characterized by FESEM, TEM, XRD and so on. The dispersion of MnO₂/CMSs in water and ethanol was also investigated. The electrochemical property of the composite was measured by cyclic voltammetry. The results show that the MnO₂/CMSs composite with appropriate capacitance performance in neutral solution was synthesized using in-situ coating technique in KMnO₄ and HNO₃ solution, the loading of MnO₂ in the composite was about 60%, and the oxidized-CMSs with oxygen-containing functional groups on their surface have good dispersion in water and ethanol.