Electrochemical Performance Of Graphene And SnO₂/Graphene As Anode Material For Lithium Ion Batteries

SnO2/graphene anode material was prepared by in situ synthesis due to the large volume change of SnO2in charge-discharge process and the excellent properties of graphene. The electrochemical performance of SnO2/graphene anode material and the effect of using different binder were investigated in this paper. The innovation of this paper lies in:1) By embedding SnO2nanoparticles into graphene nanosheets, the volume expansion and contraction of SnO2nanoparticles can by buffered by flexible graphene nanosheets.2) To those anode materials which have great volume change in charge-discharge process, aqueous binder can limit their volume change. In addition to these innovations, there are also some main results.1) After100cycles at200mA/g, the capacity of graphene maintained at445.2mAh/g, higher than212.3mAh/g of graphite. But the capacity retention of graphene is23.9%, lower than61.9%of graphite.2) The discharge capacity of SnO2/graphene can still remain at552mAh/g, even for100cycles at200mA/g, and the capacity retention is4.4times of pure SnO2. The discharge capacities of SnO2/graphene anode material at400,800and40mA/g are426.0,241.3and724.5mAh/g, respectively. The excellent rate capability should be attributed to the high electric conductivity and two dimensional nanostructures of graphene.3) The effect of SnO2/graphene anode materials’electrochemical performance was investigated by changing SnO2content. The SnO2content of three samples were59.6%,62.2%and65.5%. After100cycles, their capacity retentions were32.8%,25.4%and14.6%respectively. So there exists an optimal value of SnO2content in SnO2/graphene anode material. Through using different binders, such as PVDF, CMC and SBR, the electrochemical performance of SnO2/graphene was investigated. The research found that the capacity retention of SnO2/graphene was43.8%while using CMC and SBR as binder, higher than32.8%while using PVDF as binder.