Three-dimensional MnO2 nanowire/ZnO nanorod arrays hybrid nanostructure for high-performance and flexible supercapacitor electrode

Pure MnO2 nanowires and MnO2 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 MnO2 nanowire/ZnO nanorod hybrid nanostructured electrodes exhibit more than two times higher specific capacitance, and better capacitance retention than those of pure MnO2 nanowire electrodes. For the three-dimensional MnO2 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 MnO2 nanowire electrode is 319.6 F g−1. The electrochemical impedance spectroscopy measurements also confirm MnO2 nanowire/ZnO nanorod array hybrid electrode has better electrochemical character. The MnO2 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 MnO2 nanowire electrode has been greatly enhanced with the supporting of ZnO nanorod arrays.