Synthesis and electrochemical performance of ZnO@MnO2 core-shell column arrays on Ni Foam as electrode for supercapacitors

ZnO@MnO2 core-shell column arrays on nickel foam have been synthesized by a two-step approach, which includes hydrothermal synthesis of ZnO column arrays and electrodeposition of MnO2. The structure and morphology of hierarchical ZnO@MnO2 core-shell arrays are characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy. In addition, the hierarchical ZnO@MnO2 core-shell column arrays on nickel foam are directly used as binder-free electrodes for supercapacitors. The electrode exhibits high specific capacitance of 586.8 F g(-1) at a current density of 2 A g(-1), which is much higher than the capacitance of pure MnO2. Furthermore, the ZnO@MnO2 electrode loses 7.2% of the initial capacitance after 2000 charge-discharge cycles, which demonstrates its excellent cycling stability. These results indicate that the ZnO@MnO2 electrode is promising for high-performance supercapacitor applications.