▎ 摘　　要

In the present work we report a facile and efficient hydrothermal method to fabricate a nanocomposite of NiMoO4 and graphene nanosheets (NiMoO4/GNS) on a nickel foam (NF) substrate. The nanocomposite displayed good mechanical strength. Interestingly, NiMoO4/GNS/NF was employed as a binder-free electrode for supercapacitor application. The NiMoO4/GNS/NF electrode with high electrical conductivity showed a remarkable electrochemical performance compared to a pure NiMoO4 electrode. Herein, the role of the GNS was investigated in the electrochemical behavior of the electrode. A maximum specific capacitance of 3868 F g(-1) at 2 A g(-1) discharge current was obtained for the NiMoO4/ GNS/NF electrode. Notably, the NiMoO4/GNS/NF electrode preserved almost 76% of its maximum capacitance at a high current density of 30 A g (1), which indicates the high-rate capability of the electrode material. Also, the NiMoO4/GNS/NF electrode maintained at least 98% of its initial capacitance after 4000 operational cycles. Moreover, an asymmetric supercapacitor was assembled using NiMoO4/ GNS/NF in combination with a reduced graphene oxide (rGO)/NF electrode. The fabricated device showed excellent performance with high energy/power density and long cycling stability. It was concluded that such an excellent supercapacitive performance originates from the three-dimensional structure of the nanosheets and the intimate contact between NiMoO4 and the GNS. This work suggests that the NiMoO4/GNS/NF electrode is an exciting electrode material for energy storage purposes.