Hierarchical core/shell structures of ZnO nanorod@CoMoO4 nanoplates used as a high-performance electrode for supercapacitors

Abstract

Hierarchical core/shell structures of ZnO nanorod@CoMoO₄ nanoplates grown directly on Ni foam were synthesized by a two-step hydrothermal process, in which ZnO nanorod arrays were first grown on Ni foam substrate, and then CoMoO₄ nanoplates were grown in multiple directions on each ZnO nanorod. The as-grown ZnO@CoMoO₄ core/shell structures (on Ni foam) directly used as integrated electrodes for electrochemical capacitors demonstrated prominent electrochemical performances, i.e., a high specific capacitance of 1.52 F cm⁻² at a current density of 2 mA cm⁻², which was higher than that (772 mF cm⁻²) of the pure CoMoO₄ electrode, and a good long-term cycling stability, in which the electrodes retained 109% of the initial capacitance after 5000 cycles at a scan rate of 50 mV s⁻¹. The superior electrochemical performances suggest that the ZnO@CoMoO₄ core/shell structures could be considered as a prospective electrode material for supercapacitors.