Synthesis Of Tungsten Selenide By DC Arc And Electrochemical Study

Tungsten selenide（WSe₂）,a typical transition metal chalcogenide compound（TMDs）,exhibits stable properties at room temperature and pressure and belongs to the hexagonal system.WSe₂ has attracted wide attention in the field of electronic and photoelectric devices due to its unique electrical and optical properties,which is mainly applied in lithium-ion batteries,solar cells,optical communication lasers and preparation of new transistors.Currently,the application of WSe₂on lithium-sulfur batteries is mainly focused on electrode materials,but there is little research on the application of modifying the membrane of lithium-sulfur batteries.Therefore,this paper focused on exploring and studying the rapid preparation of WSe₂ and its application in lithium-sulfur battery membranes.Different from common WSe₂ preparation methods,DC arc plasma method was adopted in this paper.This method has the advantages of low raw material cost,simple operation process and environmental friendliness.The horizontal DC arc plasma device was used to control major experimental parameters such as working current,gas pressure and reaction time during the preparation process,so as to quickly obtain hexagonal lamellar WSe₂ material with high purity and good crystallization.The crystal structure and morphology of the samples were analyzed by X-ray diffraction,scanning electron microscope and transmission electron microscope.WSe₂ samples prepared under different synthesis parameters were compared to optimize the technological process of sample material preparation and obtain the optimal synthesis conditions.The WSe₂ obtained was directly used as a material to modify the membrane of lithium sulfur battery.Through charging and discharging at different rates,cyclic voltammetry（CV）curves,impedance and polysulfide adsorption tests,the results show that the capacity decay rate of Li-sulfur battery is only 0.015%after 100 cycles at 0.5C current density,which is significantly lower than that of ordinary Li-sulfur battery,and effectively improves the electrochemical performance of Li-sulfur battery.The experiment showed that the lithium-sulfur battery has the best electrochemical performance when the sample with WSe₂ material synthesized by DC arc plasma method has high purity and good crystallization,which further verifies that the WSe₂material can be used as a functional material to modify the membrane of lithium-sulfur battery,thus improving the comprehensive performance of the lithium-sulfur battery.