Preparation Of Separator Modification Material For High Performance Lithium Sulfur Battery And Electrochemical Performance

Lithium sulfur?Li-S?battery has attracted wide attention in recent years due to its advantages such as high theoretical specific capacity(1675 mAh g^-1),high energy density(2600 Wh kg^-1),low cost and green environmental protection.However,the shuttle effect of soluble intermediates,lithium polysulfides,results in a loss of active materials and sluggish redox kinetics,hampering the cyclability and rate capability of Li-S batteries.In this paper,titanium carbide?Ti₃C₂T_x?material was applied to the cathode and separator modification of Li-S battery,and 3D Ti₃C₂T_x aerogel structure was reasonably designed to modify the separator,which effectively inhibited the Li PSs shuttle effect and achieved excellent electrochemical performance.The specific research content is as follows:We designed and prepared 3D Ti₃C₂T_x aerogel modified separator for Li-S battery.This special structure of Ti₃C₂T_x aerogel not only effectively avoids the restacking phenomenon of 2D Ti₃C₂T_x materials to expose more active surfaces capable of absorbing polysulfides,and anchors Li PSs effectively,but also accelerates the redox reaction kinetics of polysulfides due to the high conductivity of Ti₃C₂T_x surface and effectively inhibits the shuttle effect.Therefore,Li-S battery with Ti₃C₂T_x aerogel modified separator has excellent electrochemical performance,with a very high initial discharge specific capacity of 1487 mAh g^-1 at 0.1C current density(1 C=1675 mAh g^-1),and can still reach 670 m Ah g^-1 at 2 C.After 1500 cycles at the current density of1C,an extremely low capacity decay rate of 0.037%per cycle was observed,indicating excellent cycle stability and long cycle life.This work has confirmed that Ti₃C₂T_x material can effectively inhibit the LiPSs shuttle effect,achieve high performance Li-S battery,and provide new ideas for the design of separator modification material to achieve better electrochemical performance,and remove obstacles for the commercial production of Li-S battery.