Hydrothermal synthesis of CoMoO4/Co1-xS hybrid on Ni foam for high-performance supercapacitors

Cobalt molybdate/non-stoichiometric cobalt sulfide (CoMoO4/Co1-xS) hybrid was in situ grown on nickel foam by a simple two-step hydrothermal process. The as-prepared CoMoO4/Co1-xS hybrid electrode possessed core-shell nanostructure, large surface area and high specific capacitance of 2250 F g(-1) at a current density of 1 A g(-1). Using the hybrid as anode and activated carbon (AC) as cathode, an asymmetric supercapacitor of CoMoO4/Co1-xS//AC was fabricated. The optimized supercapacitor had large potential window of 1.6 V and high capacitance of 112 F g(-1), resulting in high power density of 804.5 W kg(-1) and energy density of 39.8 Wh kg(-1). Furthermore, the supercapacitor exhibited an excellent long cycle life along with 86.4% specific capacitance retained after 5000 cycles. The superior performances and good stability of the asymmetric supercapacitor can be attributed to the unique structure of the two components in hybrid, and the positive synergistic effects of the hybrid electrodes. The facile preparation process and excellent performance presented here render the CoMoO4/Co1-xS hybrid as a promising candidate for energy storage device. (c) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.