Facile one-pot synthesis of ultrathin NiS nanosheets anchored on graphene and the improved electrochemical Li-storage properties

Abstract

A NiS/graphene (NiS/G) nanohybrid has been synthesized by a facile in situ one-pot hydrothermal route using graphite oxide, thiourea, NiCl₂·4H₂O and sodium citrate as the raw materials. The growth of NiS nanosheets and the reduction of graphite oxide occur simultaneously during the hydrothermal reactions. The hybrid exhibits a unique sheet-on-sheet structure, where ultrathin NiS sheets (below 5 nm) are anchoring on few-layer (below 8 layers) graphene sheets. The electrochemical measurements indicate that the NiS/G hybrid exhibits remarkably improved Li-storage properties compared with bare NiS, due to the ultrathin feature of the NiS sheets, unique sheet-on-sheet structure of the hybrid, and the combined conducting, buffering and confining effects of the in situ introduced graphene nanosheets.