Constructing Co3O4 Nanowire@NiCo2O4 Nanosheet Hierarchical Array as Electrode Material for High-Performance Supercapacitor.

The Co₃O₄ nanowire@NiCo₂O₄ nanosheet hierarchical array was constructed on Ni foam using hydrothermal and annealing approaches in turn, from which a NiCo₂O₄ nanosheet could self-assemble on the Co₃O₄ nanowire. The structure and morphology of the Co₃O₄ nanowire@NiCo₂O₄ nanosheet hierarchical array were characterized via XRD, EDS, SEM, and FESEM, respectively. The electrochemical performance of the composite array was measured via a cyclic voltammetry curve, galvanostatic current charge-discharge, charge-discharge cycle, and electrochemical impedance and then compared with the Co₃O₄ nanowire. The results show that the Co₃O₄ nanowire@NiCo₂O₄ nanosheet hierarchical array could reach a high value of 2034 F g^-1 at a current density of 2.5 A g^-1. After 5000 galvanostatic charge-discharge cycles, the specific capacitance of the Co₃O₄ nanowire@NiCo₂O₄ nanosheet hierarchical array could still maintain 94.7% of the original value. Therefore, the Co₃O₄ nanowire@NiCo₂O₄ nanosheet hierarchical array would be a desirable electrode material for a high-performance supercapacitor.