Facile Construction of 3D Reduced Graphene Oxide Wrapped Ni3S2 Nanoparticles on Ni Foam for High-Performance Asymmetric Supercapacitor Electrodes

3D reduced graphene oxide (rGO)-wrapped Ni3S2 nanoparticles on Ni foam with porous structure is successfully synthesized via a facile one-step solvothermal method. This unique structure and the positive synergistic effect between Ni3S2 nanoparticles and graphene can greatly improve the electrochemical performance of the NF@rGO/Ni3S2 composite. Detailed electrochemical measurements show that the NF@rGO/Ni3S2 composite exhibits excellent supercapacitor performance with a high specific capacitance of 4048 mF cm(-2) (816.8 F g(-1)) at a current density of 5 mA cm(-2) (0.98 A g(-1)), as well as long cycling ability (93.8% capacitance retention after 6000 cycles at a current density of 25 mA cm(-2)). A novel aqueous asymmetric supercapacitor is designed using the NF@rGO/Ni3S2 composite as positive electrode and nitrogen-doped graphene as negative electrode. The assembled device displays an energy density of 32.6 W h kg(-1) at a power density of 399.8 W kg(-1), and maintains 16.7 W h kg(-1) at 8000.2 W kg(-1). This outstanding performance promotes the as-prepared NF@rGO/Ni3S2 composite to be ideal electrode materials for supercapacitors.