Study On The Protection Of Metal Lithium Anode In High Capacity Lithium Sulfur Battery

Lithium-sulfur batteries have become a research hotspot in the field of energy storage due to their high capacity and low cost.However,the insufficient cycle life and safety performance of lithium metal anodes severely limit its commercial application.In order to further improve the cycling stability of the lithium metal anode,we used an"in situ"method to form a stable artificial SEI film on the surface of metal lithium,which can control the electrochemical behavior of the interface between the lithium metal and the electrolyte and inhibit the growth of lithium dendrites,thereby improving the electrochemical performance and safety of their assembled lithium/lithium symmetric batteries and lithium-sulfur batteries.The main content of this paper can be divided into the following two parts:（1）The effects of three polyaniline solutions of dimethylsulfoxide（DMSO）,N-methylpyrrolidone（NMP）and N,N-dimethylformamide（DMF）on lithium/lithium symmetrical battery are investigated by coating on lithium metal anode.NMP is preferred based on the investigations of electrochemical impedance spectroscopy.In addition,the lithium-sulfur battery assembled with polyaniline NMP solution treated lithium metal can discharge up to 1349.8 m A/g in the initial cycle with efficiency of98.22%,showing excellent rate performance and stability.（2）The effect of modified anode on the performance of lithium sulfur battery are studied by coating different ratio of lithium sulfide DMSO solution on the surface of metal lithium.The optimum ratio of Li₂S to DMSO is 1:3.When used in lithium-sulfur battery,the electrochemical performance of lithium sulfur battery is improved significantly,due to the uniform and stable stripping and deposition on smooth and flat surface of anode after repeated cycles.In summary,the SEI film constructed on lithium in this paper is feasible and effective,which can enhance the overall performance of the lithium sulfur battery as anode.