Three-dimensional MnO_2 nanowire/ZnO nanorod arrays hybrid nanostructure for high-performance and flexible supercapacitor electrode

摘要

Pure MnO_2 nanowires and MnO_2 nanowire/ZnO nanorod array hybrid nanostructure grown on carbon cloth are synthesized through a low temperature solution method for flexible and high performance supercapacitor applications. The MnO_2 nanowire/ZnO nanorod hybrid nanostructured electrodes exhibit more than two times higher specific capacitance, and better capacitance retention than those of pure MnO_2 nanowire electrodes. For the three-dimensional MnO_2 nanowire/ZnO nanorod array hybrid electrode, a high specific capacitance of 746.7 F g~(-1) (areal capacitance ～41.5 mF cm~(-2)) is obtained at a scan rate of 2 mV s~(-1) while the specific capacitance of pure MnO_2 nanowire electrode is 319.6 F g~(-1). The electrochemical impedance spectroscopy measurements also confirm MnO_2 nanowire/ZnO nanorod array hybrid electrode has better electrochemical character. The MnO_2 nanowire/ZnO nanorod array hybrid electrode shows great cycle stability, it only losses 6.5% of the initial capacitance after 1000 cycles. The energy density and power density of the hybrid electrode at 2 A g~(-1) are 63.1 Wh kg~(-1) and 950 W kg (-1), respectively. It is illustrated that the electrochemical performance of MnO_2 nanowire electrode has been greatly enhanced with the supporting of ZnO nanorod arrays.