Hydrothermal Synthesis of Hybrid Rod-Like Hollow CoWO4/Co1-xS for High-Performance Supercapacitors

A rod-like hollow cobalt tungstate/non-stoichiometric cobalt sulfide (CoWO4/Co1-xS) hybrid is successfully grown insitu on nickel foam through a simple two-step hydrothermal process. Owing to the unique hollow structure, the as-synthesized CoWO4/Co1-xS hybrid electrode possesses a large surface area and delivers a high specific capacitance of 1894.5Fg(-1) at a current density of 1Ag(-1). By using the CoWO4/Co1-xS hybrid electrode as the anode and an activated carbon (AC) electrode as the cathode, an asymmetric supercapacitor of CoWO4/Co1-xS//AC exhibits a high capacitance of 103.1Fg(-1) and high specific capacitance retention of 87.27% after 5000 cycles. Furthermore, the asymmetric supercapacitor demonstrates a maximum power density of 4000Wkg(-1) at an energy density of 22.5Whkg(-1). The superior performance of the device can be ascribed to distinctive structure and positive synergistic effects in the hybrid. The facile preparation process and excellent performance presented here indicate the CoWO4/Co1-xS hybrid to be a promising candidate electrode material for supercapacitor applications.