Graphene-wrapped nickel sulfide nanoprisms with improved performance for Li-ion battery anodes and supercapacitors

Highlights: • Nickel sulfide and graphene-wrapped nickel sulfide nanoprisms were synthesized. • Nickel sulfide nanoprisms have excellent pseudocapacitive performance. • Graphene wrapping enhanced Li-ion battery anode capacity and stability. • Graphene wrapping improved pseudocapacitive rate performance. Nickel sulfide and graphene-wrapped nickel sulfide nanoprisms were synthesized using a facile one-pot method and evaluated as anode materials for Li-ion batteries, and as supercapacitor electrodes. Graphene wrapping significantly improved the performance of nickel sulfide both as Li-ion battery anode and supercapacitor electrode. As Li-ion battery anode, graphene-wrapped nickel sulfide nanoprisms achieved an excellent specific capacity of over 1200 mAh/g after 100 cycles, and showed improved rate capability. As supercapacitor electrode, nickel sulfide nanoprisms achieved a specific capacitance of over 1000 F/g at a current density of 5 A/g, which is one of the best results reported for nickel sulfide. However, specific capacitance was much lower at 10 and 20 A/g. Introducing graphene significantly improved the specific capacitance of nickel sulfide at high current densities.