Preparation Of Moiybdenum Disulfide/graphene Nanocomposite And Its Application In Electrode Materials

Supercapacitor is one of the most promising energy storage device in the future due to its high energy density,high power density and long cyclic life.The preparation of electrode materials with good electrochemical properties is the key to promote the performance of this new type energy storage device.Molybdenum disulfide has structure similar to graphene with two-dimensional layers.The interlayer of MoS2 can store charge efficiently.However,the conductivity of MoS2 is poor.In order to improve the conductivity of electrode,MoS2 is need to compound with other materials.Coupling Molybdenum disulfide with graphene by developing their binary matrix composite can exert synergistic effects.Graphene with 2D structure can offer rich electronic transport channel and inhibit MoS2 stacking and aggregating along c axis efficiently.At present,the preparation of MoS2/rGO nanocomposite has the problem of aggregation which leads to the poor electrochemical property.In this work,MoS2/rGO nanocomposite is prepared by in-situ reaction through traditional stirring method and high-gravity method respectively.MoS2/rGO modified electrode is futher prepared and applied to supercapacitor electrode materials.The effects of synthesis condition on morphology,dispersibility and electrochemical properties of the MoS2/rGO nanocomposite are studied.The following two parts are the main contents and results of this research.1.MoS2/rGO nanocomposites were prepared by the traditional reactive precipitation in stirred tank combined with hydrothermal method.The effect of the synthesis conditions on morphology,structure and electrochemical properties of the MoS2/rGO nanocomposite were investigated.Optimal preparation conditions are as follows:reaction temperature 20 ?;reaction time 30 min;hydrothermal pH value 4.5;hydrothermal temperature 200 ?;L-cystein as reductant.The sheet-like MoS2 layers with size of about 90 nm distribute evenly on the surface of reduced graphene oxide.The specific capacitance of MoS2/rGO nanocomposite is 195.6 F·g-1 when the current density is 0.1 A·g-1.2.MoS2/rGO nanocomposites were prepared by the high gravity reactive precipitation combined with hydrothermal method.The influence of synthesis conditions on morphology,structure and electrochemical properties of the MoS2/rGO nanocomposites were studied.The optimal preparation conditions are determined.The rotating speed is 1500 r min-1.The RPB reaction time is 30 minutes.The RPB temperature is 20 ?.The feeding rate is 2 ml min-1.The concentration of hydrochloric acid in RPB system is 0.57 mol·L-1.The raw material of GO is supposed to be fully oxided.The sheet-like MoS2 layers with size of about 85 nm and distribute homogineously on the surface of reduced graphene oxide.The Molybdenum disulfide nanosheets on the surface of rGO overlap with each other to form a cross-link network structure which facilitates the collection and storage of ions.Compared with the traditional stirring method,high-gravity mehod has the advantages of reaction more fully,less side effect and higher product purity.The MoS2/rGO nanocomposites prepared by the high-gravity method have better electrochemical properties.When the current density of MoS2/rGO nanocomposite is 0.1 A g-1,the specific capacitance reaches 257.8 F·g-1.Moreover,the MoS2/rGO nanocomposites can maintain 65%of initial capacitance after 500 cycles which perform a better clectrochemical stability compared with the composite prepared by traditional stirring mehod(31%).