Dual-additives enable stable electrode-electrolyte interfaces for long life Li-SPAN batteries  

作　　者：Zhenqiang Guo Huicong Yang Qian Wei Shengjun Xu Guangjian Hu Shuo Bai Feng Li 

机构地区：[1]School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China [2]Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [3]Department of Biochemistry and Molecular Biology,College of Life Science,China Medical University,Shenyang 110122,China [4]Dalian National Laboratory for Clean Energy,Dalian 116023,China [5]Shenyang King Power Technology Co.,Ltd.,Shenyang 110016,China

出　　处：《Chinese Chemical Letters》2024年第5期459-465,共7页中国化学快报（英文版）

基　　金：financial support from the National Natural Science Foundation of China(Nos.52072378,22209189);the National Key R&D Program of China(No.2022YFB3803400);the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDA22010602 and 2022YFB3803400);Shenyang Science and Technology Program(No.22-322-3-19)。

摘　　要：Sulfurized polyacrylonitrile(SPAN)is proposed as a promising cathode material for lithium sulfur batteries.However,the continuous side reactions at the electrolyte-electrode interfaces as well as the slow redox kinetics of SPAN cathode deteriorate the electrochemical performance.In this study,an electrolyte with dual-additives comprising 2-fluoropyridine(2-FP)and lithium difluorobis(oxalato)phosphate(LiDFBOP)was used to improve the performance of Li||SPAN cells.2-FP has a lower lowest occupied molecular orbital energy than that of the solvents in the electrolyte,leading to its prior reduction.A LiF-rich film can be formed on the electrode,effectively improving the stability of the electrolyte-electrode interfaces and prolonging the life.Simultaneously,LiDFBOP could form an electrolyte-electrode interface film containing a large amount of Li_(x)PO_(y)F_(z) species,compensating for the kinetic deterioration caused by the lower ionic conductive of LiF formed at the electrolyte-electrode interface.Hence,an electrode-interface film with good chemical stability and high Li^(+) transport was established by LiF and Li_(x)PO_(y)F_(z)-rich species.The Li||SPAN cell with the electrolyte containing dual-additives demonstrates an excellent capacity retention of 97.5%after 200 cycles at 1.0 C,25℃,comparing to 56.2%capacity retention without additives.Moreover,the rate capacities of cells with dual-additives can reach 1128.1 mAh/g at 5 C,comparing to only 813.5 mAh/g using electrolyte without additives.Our results shown that the dual-additives in electrolyte provide a promising strategy for practical application of lithium sulfur batteries with SPAN cathodes.

关 键 词：Sulfurized polyacrylonitrile Lithium metal Interface film 2-Fluoropyridine Difluorobis(oxalato)phosphate 

分 类 号：TM912[电气工程—电力电子与电力传动] O646[理学—物理化学]