Synthesis And Lithium Storage Behavior Of MoS₂/graphene As Anode Material For Lithium Ion Batteries

MoSi/graphene composites, which combines the excellent properties of graphene and the three dimensional structure of MoS2, was in situ synthesised through hydrothermal method due to the poor conductivity and cyclic performance of MoS2in charge-discharge process. The micro structure and morphology were characterised by X-ray diffraction(XRD), scanning electron microscope(SEM) and transmission electron microscope(TEM) mearsurements. The electrochemical performances have been investigated by means of various techniques. The innovation lies in that compsites of3D MoS2flower-like structure was prepared by hydrothermal method, and its electrochemical performances was improved by introducing excellent properties of graphene. The main results are obtained as follows.(1) After microwaving, GO was reduced into graphene with thickness of2-4layer carbon atoms, and the micrometer-sized typical wrinkles could were observed on the surface of graphene. Pore structure analysis proved the layered structure and slit type pore structure of graphene, with BET specific surface area of436.8m2/g, and a narrow pore size distribution.(2)3D flower-like structure MoS2was in situ synthesised through hydrothermal method under the condition of240℃, Na2MoO4and CS(NH2)2as Mo resource and S resource respectively.The flower-like structure MoS2was assembled by layered MoS2nanosheets, with diameter of1-2μm HRTEM proved the obvious layered structure. Pore structure analysis showed the slit type pore structure with a narrow pore size distribution of4-5nm.(3) Electrochemical analysis showed that MoS2/graphene performed better than pure MoS2in reversible capacity, cyclic stability and rate capability. The discharge capacity of MoS2/graphene composites is735.2mAh/g after100cycles at100mAh/g, with the capacity retention60.4%. Capacities at100,200,400,800,1000mAh/g are689.6,620.5,490.3,411.9,349.6mAh/g. The resistance of MoS2/graphene composites was also significantly lower than that of MoS2. The excellent electrochemical properties should be attributeed to the high electric conductivity and the two-dimensional nanostructure of graphene. The electrochemical performance was effected by the ratio of graphene. Of all the4samples, composite of which GO dosage was0.01g, showed the best cyclic stability and rate capability.