Electron delocalization-enhanced sulfur reduction kinetics on an MXene-derived heterostructured electrocatalyst  

作　　者：Yunmeng Li Yinze Zuo Xiang Li Yongzheng Zhang Cheng Ma Xiaomin Cheng Jian Wang Jitong Wang Hongzhen Lin Licheng Ling 

机构地区：[1]State Key Laboratory of Chemical Engineering,Key Laboratory of Specially Functional Polymeric Materials and Related Technology(Ministry of Education),East China University of Science and Technology,Shanghai 200237,China [2]Institute of New Energy Materials and Engineering,College of Materials Science and Engineering,Fuzhou University,Fuzhou 350108,China [3]Key Laboratory of Specially Functional Polymeric Materials and Related Technology(Ministry of Education),School of Materials Science and Engineering,East China University of Science and Technology,Shanghai 200237,China [4]i-Lab&CAS Key Laboratory of Nanophotonic Materials and Device Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences,Suzhou 215123,China [5]Helmholtz Institute Ulm(HIU),D89081 Ulm,Germany

出　　处：《Nano Research》2024年第8期7153-7162,共10页纳米研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.U1710252);the Natural Science Foundation of Jiangsu Province(BK.20210130);Innovative and Entrepreneurial Doctor in Jiangsu Province(No.JSSCBS20211428);China Postdoctoral Science Foundation(No.2023M731084);Shanghai Sailing Program of China(No.23YF1408900);the Fundamental Research Funds for the Central Universities(No.JKD01231701).

摘　　要：Lithium-sulfur(Li-S)batteries mainly rely on the reversible electrochemical reaction of between lithium ions(Li^(+))and sulfur species to achieve energy storage and conversion,therefore,increasing the number of free Li^(+)and improving the Li^(+)diffusion kinetics will effectively enhance the cell performance.Here,Mo-based MXene heterostructure(MoS_(2)@Mo_(2)C)was developed by partial vulcanization of Mo_(2)C MXene,in which the introduction of similar valence S into Mo-based MXene(Mo_(2)C)can create an electron delocalization effect.Through theoretical simulations and electrochemical characterisation,it is demonstrated that the MoS_(2)@Mo_(2)C heterojunction can effectively promote ion desolvation,increase the amount of free Li^(+),and accelerate Li^(+)transport for more efficient polysulfide conversion.In addition,the MoS_(2)@Mo_(2)C material is also capable of accelerating the oxidation and reduction of polysulfides through its sufficient defects and vacancies to further enhance the catalytic efficiency.Consequently,the Li-S battery with the designed MoS_(2)@Mo_(2)C electrocatalyst performed for 500 cycles at 1 C and still maintained the ideal capacity(664.7 mAh·g^(−1)),and excellent rate performance(567.6 mAh·g^(−1)at 5 C).Under the extreme conditions of high loading,the cell maintained an excellent capacity of 775.6 mAh·g^(−1)after 100 cycles.It also retained 838.4 mAh·g^(−1)for 70 cycles at a low temperature of 0℃,and demonstrated a low decay rate(0.063%).These results indicate that the delocalized electrons effectively accelerate the catalytic conversion of lithium polysulfide,which is more practical for enhancing the behaviour of Li-S batteries.

关 键 词：delocalized electron lithium sulfur batteries MXene-based heterostructures catalytic desolvation multi-catalytic sites 

分 类 号：O64[理学—物理化学]