Polybenzimidazole functionalized electrolyte with Li-wetting and self-fluorination functionalities for practical Li metal batteries

作     者：Dongjiang Chen Yuanpeng Liu Chuan Xia Yupei Han Qingwei Sun Xuchang Wang Wei Chen Xian Jian Weiqiang Lv Jianyi Ma Weidong He 

作者机构：National Key Laboratory of Science and Technology on Advanced Composites in Special Environmentsand Center for Composite Materials and StructuresHarbin Institute of TechnologyHarbinChina School of PhysicsUniversity of Electronic Science and Technology of ChinaChengduChina School of Materials and EnergyUniversity of Electronic Science and Technology of ChinaChengduChina Institute of Atomic and Molecular PhysicsSichuan UniversityChengduSichuanChina 

出 版 物：《InfoMat》 (信息材料（英文）)

年 卷 期：2022年第4卷第5期

页      面：174-186页

核心收录：

学科分类：0808[工学-电气工程] 08[工学] 

基　　金：Applied Fundamental Research Fund of Sichuan Province,Grant/Award Number:2019YJ0169 Fundamental Research Funds for the Chinese Central Universities,Grant/Award Number:ZYGX2015Z003 Natural Science Foundation of China,Grant/Award Number:51972043 Science&Technology Support Funds of Sichuan Province,Grant/Award Number:2016GZ0151 

主　　题：flame-retardant properties Li metal polybenzimidazole solid polymer electrolyte uniform Li deposition 

摘      要：Rough Li plating,low ionic conductivity,and low thermal stability of conventional electrolytes post-primary challenges for achieving reliable high-capacity rechargeable lithium batteries,for which lithiummetal is frequently proposed as themost promising anode *** low-polarity commercial polypropylene/polyethylene separators fail to support the application of high-energy-density Li anodes due to their rigid physicochemical properties and the high reactivity of Li metal,leading to fatal dendrite formation and vigorous exothermic reaction with ***,we develop a Li-wetting,flame-retardant binary polymer electrolyte by functionalizing poly(vinylidene fluoride)(PVDF)separators with nonflammable polybenzimidazole(PBI)to build safe room-temperature solid-state electrolyte membranes.A dendrite-free LiFePO4 cell with the solid polymer electrolyte(SPE)delivers a discharge capacity of 127 mAh g^(-1) at 25℃ with a capacity retention of 87.5%after 500 cycles at 0.5℃(0.15 mA cm^(-2)).Phase-field simulations and density functional theory calculations demonstrate that the negatively charged benzimidazole chains of PBI own superior affinity to lithium bis(trifluoromethanesulfonyl)imide(LiTFSI),and shares overlapping electron density with Li anode,giving rise to accelerated Li^(+)conduction at room temperature and uniform Li electrodeposition at the electrolyte/Li metal *** SPE is also flame-retardant since heat-resistant polytetrafluoroethylene and a dense,heat-blocking graphitized carbon layer are formed in intense heat throughdehydrogenation/fluorination of PVDF under the catalysis of Lewis base imidazole rings and the decomposition of benzimidazole rings in *** such fire-resistant mechanism is ever reported in conventional electrolytes.