Novel method for preparation of metal-sulfide@reduced-graphene-oxide with high energy storage performance

Abstract Transition-metal sulfide with high theoretical capacity is a promising anode material. However, the poor conductivity and pulverization of the transition-metal sulfide caused by huge volume changes lead to a fast decay in specific capacity. In this study, we prepared a three-dimensional sandwich-structured anode material consisting of metal sulfides and reduced graphene oxide (rGO), which can address the above problems. The anode material is composed of Ni7S6/MnS2 micro/nanosheets uniformly attached on the rGO synthesized by an in-situ sulfuration of a NiMn2O3(OH)4@rGO precursor. The Ni7S6/MnS2@rGO composite exhibited a high electrochemical performance, which is mainly ascribed to the three-dimensional sandwich-structures, because it can well relieve the volume change and promote electron mobility and ion diffusion in the discharge/charge process. Furthermore, this method can be used to prepare other sulfides such as NiS2@rGO and Ni7S6/CoS2@rGO. The proposed universal preparation method and excellent electrochemical performance of Ni7S6/MnS2@rGO make the composite attractive anode material.