Enhanced electrochemical performance of MWNT@MnO2 composites in polymerized ionic liquids

Abstract

In this article, we report a newly devised composite electrode for electrochemical capacitors, by depositing manganese dioxide (MnO₂) on the surface of carbon nanotubes via a spontaneous redox reaction. X-ray diffraction and transmission electron microscopic studies demonstrated a homogeneous coating of layered MnO₂ on the surface of the carbon nanotubes. The MWNT@MnO₂ composite electrode displayed enhanced capacity performance and rate capability as compared to the MnO₂ electrode. Introduction of a thin layer of polymerized ionic liquid on the surface of the composite electrode enhanced the utilization rate of MnO₂ and improved the conductivity of the resultant electrode. Electrochemical tests confirmed the augmented capacity performance and rate capabilities of the polyion-coated composite electrode.