Fluoroethylene carbonate(FEC)is frequently added to the electrolyte in low-temperature lithium metal batteries to improve performance.However,its use results in a Li_(2)CO_(3)-rich solid electrolyte interphase(SEI)on ...Fluoroethylene carbonate(FEC)is frequently added to the electrolyte in low-temperature lithium metal batteries to improve performance.However,its use results in a Li_(2)CO_(3)-rich solid electrolyte interphase(SEI)on the lithium anode,which leads to continuous thickening of the SEI under low-temperature cycling.In this study,the local high-concentration electrolyte was utilized to optimize the solvation structure of Li^(+),thereby adjusting the composition and structure of the SEI.Consequently,the Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cell achieved over 99.5%Coulombic efficiency at-20℃ and sustained over 50 cycles at a 1 C rate at-40℃,with a specific capacity exceeding 110 mAh/g and a high Coulombic efficiency above 99%.The combined use of ethyl acetate(EA)and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether(TFTFE)promoted the formation of a layered SEI on the lithium anode,enabling efficient Li^(+)desolvation at low temperatures.This provides a novel strategy for designing lowtemperature lithium metal battery electrolytes.展开更多
基金supported by the Key Research and Development Program of Shandong Province,China(2021CXGC010401)the National Key Research and Development Program of China(2022YFB2502102)+1 种基金the National Natural Science Foundation of China(52272185)the Beijing Outstanding Young Scientists Program(BJJWZYJH01201910007023).
文摘Fluoroethylene carbonate(FEC)is frequently added to the electrolyte in low-temperature lithium metal batteries to improve performance.However,its use results in a Li_(2)CO_(3)-rich solid electrolyte interphase(SEI)on the lithium anode,which leads to continuous thickening of the SEI under low-temperature cycling.In this study,the local high-concentration electrolyte was utilized to optimize the solvation structure of Li^(+),thereby adjusting the composition and structure of the SEI.Consequently,the Li||LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) cell achieved over 99.5%Coulombic efficiency at-20℃ and sustained over 50 cycles at a 1 C rate at-40℃,with a specific capacity exceeding 110 mAh/g and a high Coulombic efficiency above 99%.The combined use of ethyl acetate(EA)and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether(TFTFE)promoted the formation of a layered SEI on the lithium anode,enabling efficient Li^(+)desolvation at low temperatures.This provides a novel strategy for designing lowtemperature lithium metal battery electrolytes.
