High performance Ni3S2/3D graphene/nickel foam composite electrode for supercapacitor applications

Nano-structured Ni3S2 is regarded as one of the most promising supercapacitor (SC) electrode materials due to its unique heazlewoodite phase and high electronic conductivity. However, preparation of Ni3S2 nanostructures with controllable chemical stoichiometry and morphology is still a challenge issue. Herein, we report a novel Ni3S2/3D graphene/nickel foam (Ni3S2/3D G/NF) composite electrode prepared by a chemical vapor deposition (CVD) followed by an electrodeposition. The as-prepared Ni3S2/3D G/NF composite electrode is stable with good chemical stoichiometry, binder-free and exhibits an excellent specific capacitance up to 2585 F/g with current density of 1 A/g,a high capacitance retention rate similar to 70.68% as the current density increases to 30 A/g, and a capacitance remaining 88.9% after 5000 cycles of charge and discharge with the current density of 20 A/g. The perfect Ni3S2 heazlewoodite phase and good contact between Ni3S2 and the surface of 3D G/NF are believed to be responsible for the greatly improved conductivity and specific surface area of the as-prepare composite electrode. Our result has provided an effective way to significantly improve the capacitive property of Ni3S2 and shown a great potential for realizing its practical SC applications.