Diluent decomposition-assisted formation of Li F-rich solid-electrolyte interfaces enables high-energy Li-metal batteries  

作　　者：Junbo Zhang Haikuo Zhang Ruhong Li Ling Lv Di Lu Shuoqing Zhang Xuezhang Xiao Shujiang Geng Fuhui Wang Tao Deng Lixin Chen Xiulin Fan 

机构地区：[1]Shenyang National Laboratory for Materials Science,Northeastern University,Shenyang 110819,Liaoning,China [2]State Key Laboratory of Silicon Materials,School of Materials Science and Engineering,Zhejiang University,Hangzhou 310027,Zhejiang,China [3]Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province,Hangzhou 310013,Zhejiang,China [4]Department of Chemical and Biomolecular Engineering,University of Maryland,College Park 20742,MD,USA

出　　处：《Journal of Energy Chemistry》2023年第3期71-79,I0003,共10页能源化学（英文版）

基　　金：supported by the National Natural Science Foundation of China(22072134,22161142017,and U21A2081);the Natural Science Foundation of Zhejiang Province(LZ21B030002);the Fundamental Research Funds for the Zhejiang Provincial Universities(2021XZZX010);the Fundamental Research Funds for the Central Universities(2021FZZX001-09);“Hundred Talents Program” of Zhejiang University。

摘　　要：Passivation by the inorganic-rich solid electrolyte interphase(SEI),especially the LiF-rich SEI,is highly desirable to guarantee the durable lifespan of Li metal batteries(LMBs).Here,we report a diluent with the capability to facilitate the formation of LiF-rich SEI while avoiding the excess consumption of Li salts.Dissimilar to most of reported inert diluents,heptafluoro-l-methoxypropane(HM) is firstly demonstrated to cooperate with the decomposition of anions to generate LiF-rich SEI via releasing Fcontaining species near Li surface.The designed electrolyte consisting of 1.8 M LiFSI in the mixture of1,2-dimethoxyethane(DME)/HM(2:1 by vol.) achieves excellent compatibility with both Li metal anodes(Coulombic efficiency~99.8%) and high-voltage cathodes(4.4 V LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811) and 4.5 V LiCoO_(2)(LCO) vs Li^(+)/Li).The 4.4 V Li(20μm)‖NMC811(2.5 mA h cm^(-2)) and 4.5 V Li(20μm)‖LCO(2.5 mA h cm^(-2)) cells achieve capacity retentions of 80% over 560 cycles and 80% over 505 cycles,respectively.Meanwhile,the anode-free pouch cell delivers an energy density of~293 W h kg^(-1)initially and retains 70% of capacity after 100 deep cycles.This work highlights the critical impact of diluent on the SEI formation,and opens up a new direction for designing desirable interfacial chemistries to enable high-performance LMBs.

关 键 词：DILUENT Solvation structure LiF-rich SEI Li metal batteries Localized high-concentration electrolyte 

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