Enhanced electrochemical performance of flower-like SnS2/NC@GO composite anodes for lithium-ion batteries

Abstract

Flower-like SnS2/NC@GO composite powders are successfully synthesized by freeze-drying a mixed suspension of graphene oxide (GO) and melamine decorating flower-like SnS2 powders with following annealing processes, which are confirmed by scanning electron microscope, X-ray diffraction, transmission electron microscope, Raman spectra and thermogravimetric analysis. These results demonstrate that a three dimensional network provided by GO wraps uniformly on the surface of flower-like SnS2 powders coated with the N-doped carbon (NC) layer derived from melamine, in which the NC layer can effectively relieve the volume expansion and the conductive network can supply plentiful charge transfer channels for electrons and lithium ions. When served as an anode material, the coin cell with the SnS2/NC@GO composite electrode exhibits an outstanding cyclic property and delivers an average discharge specific capacity of 761.5, 569.7, 502.6, 415.1 and 290.3 mAh g−1 at 100, 200, 300, 500 and 1000 mA g−1, respectively. The cell can deliver a high discharge specific capacity of 621.1 mAh g−1 when the current density recovers suddenly to 100 mA g−1. Moreover, the cell with the SnS2/NC@GO composite electrode presents an enhanced lithium ions diffusion coefficient of 1.872 × 10−14 cm2 s−1 and a low charge transfer resistance of 129.1 Ω. It is no doubt that the as-prepared SnS2/NC@GO composite with improved electrochemical properties can be used as a promising anode material for lithium-ion batteries.