Three-dimensional elastic ultrathin reduced graphene oxide coating SnS2 hierarchical microsphere as lithium ion batteries anode materials

Three-dimensional elastic ultrathin reduced graphene oxide coating SnS2 hierarchical microsphere (3D SnS2@RGO) have been successfully prepared by a convenient hydrothermal method. The morphology and structure of the 3D SnS2@RGO are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectra. It is found that numerous of nanoflakes-assembly SnS2 microspheres are wrapped by ultrathin reduced graphene oxide nanosheets, which form a three-dimensional net-like structure. The electrochemical performance of 3D SnS2@RGO electrode was evaluated by cyclic voltammetry, galvanostatic charge-discharge tests and electrochemical impedance spectroscopy measurement. When evaluated as lithium ion batteries anode material, 3D SnS2@RGO electrode manifest better cycling performance (reserving 942 mAh g−1 after 100 cycles) and higher rate capability (689 mAh g−1 at the rate of 1000 mA g−1) than that of pure SnS2 (retaining 216 mAh g−1 after 100 cycles) (only 10.8 mAh g−1 at the current density of 1000 mA g−1). The excellent electrochemical performance can be attributed to the improvement of lithium ion diffusion and ionic conductivity which is caused by graphene-coating.