羟基功能化Ti_(3)C_(2)多硫化物锚定性能的第一性原理研究

First-principles Study on the Polysulfide Anchoring Properties of Hydroxyl Functionalized Ti_(3)C_(2)

锂硫电池(Li-S)放电过程中多硫化锂(LiPSs)的穿梭效应严重阻碍其商业化进程.采用导电框架锚定LiPSs,并为正极活性物质提供导电通道是提高Li-S电池电化学循环稳定性的有效策略.采用密度泛函理论研究羟基功能化碳化钛(Ti_(3)C_(2)(OH)_(2))作为Li-S电池锚定材料的可行性.计算结果表明,Ti_(3)C_(2)(OH)_(2)单层表面氢原子和氧原子与LiPSs中硫原子和锂原子之间的强相互作用,可以抑制穿梭效应.高覆盖率下LiPSs之间的相互作用可以调控其在基底表面的分解.该研究将为Ti_(3)C_(2)(OH)_(2)作为Li-S电池导电框架的应用提供理论支撑.

The shuttle effect of lithium polysulfide(LiPSs)during discharge seriously hinders the commercialization of lithium-sulfur(Li-S)battery.The design of conductive scaffolds,which can anchor LiPS and provide conductive channels of cathode active materials,is a effective strategy to improve the electrochemical cycling stability of Li-S battery.In this article,the feasibility of hydroxyl functionalized titanium carbide(Ti_(3)C_(2)(OH)_(2))as Li-S battery anchoring material is studied by using density functional theory.The calculated results show that the shuttle effect can be suppressed by the strong interaction between H/O atoms of Ti_(3)C_(2)(OH)_(2)surface and S/Li atoms of LiPS molecule.Interaction between LiPSs under high coverage can regulate the their decomposition on substrate surface.This theoretical study will provide theoretical support for the study of Ti_(3)C_(2)(OH)_(2)as a conductive scaffolds for Li-S batteries.