Study On The Electrochemical Performance Of Several Graphene-based Metal Sulfur Multi-phase Composites And Their Fabrication

As a new kind of two-dimensional carbon material, graphene has attracted enormous attentions in many fields and it possesses the superiority to the fields of energy storage materials, sensor devices, Li-ion battery and so on. As a kind of pseudocapacitance electrode materials, metal sulfide has excellent electrochemical properties. To take the advantage high electrical-conductivity of graphene and high capacitance of metal sulfide, we combine them together to prepare a multi-phase composite with excellent electrochemical properties.In this paper, a one-step hydrothermal strategy was designed for the synthesis of CdS/RGO composite. Due to the addition of graphene, the electrochemical performance of the composite increased obviously than pure CdS. Moreover, the composite has a good photocatalytic performance.The CuS/RGO composite was preapred by two different menthods. The capacitance of this composite can reach 212.5 F/g through one-step hydrothermal menthod. Then, we converted CuO/RGO to CuS/RGO composite successfully by ion exchange in the two-steps hydrothermal strategy. This method provides a new way to contol the microstructure of the composite.Futher, the CoS/RGO composite was prepared successfully. We prepared the three-dimentional composite by controlling the structure of graphene. The capacitiance of this composite (564 F/g) was better than pure CoS (433 F/g). Finally, the graphene was introduced into lithium-sulfur battery cathode material, and the S/RGO composite has a good electrochemical performance.The results of FT-IR, Raman, XRD, XPS and TEM showed that the garphene and mental sulfur composite was prepared successfully. In the composite, the improvement of the electrochemical properties can be attributed to the synergistic effect between graphene and metal sulfide.