A flexible design strategy to modify Ti3C2Tx MXene surface terminations via nucleophilic substitution for long-life Li-S batteries  

作　　者：Tianpeng Zhang Wenlong Shao Siyang Liu Zihui Song Runyue Mao Xin Jin Xigao Jian Fangyuan Hu 

机构地区：[1]School of Materials Science and Engineering,State Key Laboratory of Fine Chemicals,Key Laboratory of Energy Materials and Devices(Liaoning Province),Dalian University of Technology,Dalian 116024,Liaoning,China [2]State Key Laboratory of Fine Chemicals,Department of Polymer Science&Materials,Liaoning Province Engineering Research Centre of High Performances Resins,Dalian University of Technology,Dalian 116024,Liaoning,China

出　　处：《Journal of Energy Chemistry》2022年第11期349-358,I0010,共11页能源化学（英文版）

基　　金：the support from CNPC Innovation Found(2021DQ02-1001);Liao Ning Revitalization Talents Program(XLYC1907144);Xinghai Talent Cultivation Plan(X20200303)。

摘　　要：MXene-based materials have gained considerable attention for lithium-sulfur(Li-S)batteries cathode materials due to their superior electric conductivity and high affinitive to polysulfides.However,there are still challenges in modifying the surface functional groups of MXene to further improve the electrochemical performance and increase the structure variety for MXene-based sulfur host.Herein,we report an efficient and flexible nucleophilic substitution(S_(N))strategy to modify the Ti_(3)C_(2)T_(x) surface terminations and purposefully designed Magnolol-modified Ti_(3)C_(2)T_(x)(M-Ti_(3)C_(2)T_(x))as powerful cathode host materials.Benefiting from more C-Ti-O bonds forming and diallyl groups terminations reducing after the dehalogenation and nucleophilic addition reactions,the given M-Ti_(3)C_(2)T_(x) electrode could effectively suppress the lithium polysulfides shuttling via chemisorption and C—S covalent bond formation.Besides,the Magnolol-modified Ti_(3)C_(2)T_(x) significantly accelerates polysulfide redox reaction and reduces the activation energy of Li_(2) S decomposition.As a result,the as-prepared M-Ti_(3)C_(2)T_(x) electrode displays an excellent rate capability and a high reversible capacity of 7.68 mAh cm^(-2)even under 7.2 mg cm^(-2)S-loaded with a low decay rate of 0.07%(from 2 nd cycle).This flexible surface-modified strategy for MXene terminations is expected to be extended to other diverse MXene applications.

关 键 词：Lithium-sulfur batteries Nucleophilic substitution Magnolol-modified Ti3C2Tx Multifunctional sulfur host Long-cycle life 

分 类 号：TM912[电气工程—电力电子与电力传动] TB34[一般工业技术—材料科学与工程]