Excellent Electrochemical Performance Hierarchical Co3O4@Ni3S2 core/shell nanowire arrays for Asymmetric Supercapacitors

Three-dimensional hierarchical Co3O4@Ni3S2 core/shell nanowire arrays were designed and fabricated on nickel foam via a facile two-step route for supercapacitor applications. Compared with the pristine Co3O4 nanowire arrays and Ni3S2 nanosheets, the hierarchical nanostructure demonstrates much more excellent capacitive behaviors. The Co3O4@Ni3S2 electrode exhibited an ultrahigh specific capacitance of 1710 F g(-1) at 1 Ag-1 and 1474 F g(-1) at 10 A g(-1). An asymmetric supercapacitor based on Co3O4@Ni3S2 core/shell nanowire arrays on nickel foam as the positive electrode and activated carbon (AC) as negative electrode was successfully assembled. A specific capacitance of 126.6 F g(-1) at 1 Ag-1 (retaining 83.5% capacity after 5000 cycles at a current density of 2 A g(-1)) and an outstanding energy density of 44.9 Wh kg(-1) was achieved. The remarkable electrochemical properties could be attributed to the unique hierarchical architectures of Co3O4@Ni3S2 core-shell nanowire arrays on 3D on nickel foam and a rational combination of two electrochemical pseudocapacitor materials. The results indicate that our asymmetric supercapacitors have great potential in energy storage device applications. (C) 2016 Elsevier Ltd. All rights reserved.