四川大学学报（自然科学版）2025，Vol.62Issue(6)：1456-1462,7.DOI:10.19907/j.0490-6756.250083
碲基电解液添加剂提高锂硫电池循环稳定性能
Tellurium-based electrolyte additive enhances cycling stability of lithium-sulfur batteries
摘要
Abstract
Lithium-sulfur(Li-S)batteries are regarded as one of the most promising next-generation energy storage systems due to their high theoretical energy density(～2600 Wh·kg-1),low cost,and the abundance of sulfur.Their high energy potential makes them attractive for applications in electric vehicles and large-scale grid storage.However,their practical deployment is significantly hindered by multiple challenges,including the severe shuttle effect caused by the dissolution and migration of lithium polysulfides(LiPSs),the intrinsi-cally sluggish redox kinetics of sulfur species,and the uncontrolled growth of lithium dendrites on the anode.These issues result in rapid capacity fading,poor Coulombic efficiency,and safety concerns,making interfa-cial stabilization a key research focus.In this study,we propose bis(pentafluorophenyl)telluride((C6F5)2Te)as a multifunctional electrolyte additive designed to simultaneously address these issues.The molecule was synthesized via a Williamson-type etherification reaction between sodium telluride and pentafluoroiodoben-zene,and its chemical structure was confirmed by 19F NMR spectroscopy.Density functional theory(DFT)calculations reveal that the electron-deficient pentafluorophenyl groups on(C6F5)2Te facilitate strong interac-tions with LiPSs,leading to enhanced conversion kinetics and improved interfacial electron redistribution.A combination of electrochemical characterizations,including galvanostatic cycling,electrochemical impedance spectroscopy(EIS),cyclic voltammetry(CV),and lithium symmetric cell testing,was conducted to assess the additive's performance.Surface analyses by X-ray photoelectron spectroscopy(XPS)and scanning elec-tron microscopy(SEM)were also employed to investigate interfacial evolution.The experimental results demonstrate that(C6F5)2Te promotes the stepwise transformation of LiPSs,effectively mitigating their shuttle effect.Moreover,the additive undergoes preferential reduction on the lithium anode,forming a LiF-rich solid electrolyte interphase(SEI)that promotes uniform Li deposition and suppresses dendrite formation.EIS analysis reveals significantly lower interfacial resistance and improved ion transport.With 1 wt％addi-tive,the Li-S cell exhibits excellent cycling stability,retaining 49.89％of its capacity after 500 cycles at 0.5 C,far superior to the baseline cell(17.17％).In summary,(C6F5)2Te functions as a bifunctional interfa-cial modifier that simultaneously stabilizes both anode and cathode surfaces,accelerates polysulfide conver-sion,and enhances long-term battery stability.This work provides a feasible strategy for electrolyte engineer-ing in high-performance Li-S batteries and offers new insights into the design of multifunctional molecular ad-ditives.关键词
锂硫电池/联五氟苯碲/添加剂/电化学性能Key words
Lithium-sulfur batteries/(C6F5)2Te/Additives/Electrochemical performanc分类
化学化工引用本文复制引用
黄秉轩,王琛,张华俊,唐仕海,刘芝孟,何欣..碲基电解液添加剂提高锂硫电池循环稳定性能[J].四川大学学报（自然科学版）,2025,62(6):1456-1462,7.基金项目
四川大学基本科研业务基金(SCU2023HGXY) （SCU2023HGXY）
