Dandelion‐like Nanospheres Synthesized by CoO@CuO Nanowire Arrays for High‐Performance Asymmetric Supercapacitors

Abstract Recently, three‐dimensional‐structure materials have attracted enormous attention in energy‐storage fields on account of their excellent electrochemical performance. In this study, hierarchical nanospheres consisting of mesoporous CoO@CuO nanowires on a three‐dimensional conductive Ni foam are prepared by a one‐step hydrothermal method combined with a subsequent annealing process. Compared to CoO or CuO alone, the as‐obtained CoO@CuO/Ni hybrid nanowires show good electronic conductivity owning to the abundant existence of O vacancies in them. In a three‐electrode system, the area capacitance of the prepared CoO@CuO/Ni electrode reaches 2.94 F cm −2 (1.32 C cm −2 ) at 1 mA cm −2 , and the CoO@CuO/Ni electrode presents an outstanding cycle performance. Moreover, a CoO@CuO/Ni//AC ASC asymmetric supercapacitor is fabricated and found to display a high energy density of 20.22 Wh kg −1 at 800 W kg −1 . Hence, this novel CoO@CuO/Ni hybrid nanowires with excellent electrochemical properties shows outstanding potential in the practical application of high‐energy storage devices.