储能科学与技术2025，Vol.14Issue(9)：3249-3258,10.DOI:10.19799/j.cnki.2095-4239.2025.0217
FEC与VC在锂离子电池石墨负极界面行为研究
Interfacial behavior of FEC and VC at graphite anode of lithium-ion batteries
摘要
Abstract
In lithium-ion batteries,electrolyte additives such as fluorinated ethylene carbonate(FEC)and vinylene carbonate(VC)have been widely employed to enhance the stability of the electrode/electrolyte interface;however,their effects on graphite electrodes remain unclear.In this study,the interfacial behavior of FEC and VC on graphite anodes in lithium-ion batteries is systematically investigated.The distinct mechanisms by which FEC and VC influence graphite surfaces are elucidated through various characterization techniques,including cyclic voltammetry,electrochemical impedance spectroscopy,scanning electron microscopy,transmission electron microscopy,and X-ray photoelectron spectroscopy.Electrochemical impedance results indicate that,in Li|Gr cells,the total impedance before and after solid electrolyte interphase(SEI)formation with FEC is lower than that with VC,whereas in Li|Ref|Gr cells,the total impedance with FEC is higher than that with VC.The interfacial impedances are further deconvoluted using the electrochemical impedance spectroscopy-distribution of relaxation time(EIS-DRT)method to determine the SEI impedance,the charge-exchange impedance at the SEI-graphite interface,and the SEI-electrolyte interface charge-exchange impedance in Li|Gr cells.The characteristic relaxation times of FEC and VC are essentially consistent for each component,with values of 5×10-5 s for SEI impedance,3×10-4 s for SEI-graphite interface charge exchange,and 5×10-3 s for SEI-electrolyte interface charge exchange.The results show that VC reduction at 0.77 V forms an organic-rich SEI,significantly reducing impedance at the graphite interface but exhibiting poor compatibility with lithium metal,thereby increasing the total cell impedance.In contrast,FEC reduction at 1 V forms a LiF-rich SEI on the graphite surface,which increases graphite interface impedance yet greatly improves the stability of the lithium metal electrode.The adverse effect of FEC on the graphite interface is outweighed by its stabilizing effect on lithium metal,ultimately reducing the total cell impedance.This study provides important experimental insights and theoretical guidance for the optimized design of electrolytes in lithium-ion batteries.关键词
锂离子电池/电极/电解液界面/氟代碳酸乙烯酯/碳酸亚乙烯酯Key words
lithium-ion battery/electrode/electrolyte interface/fluorinated ethylene carbonate/vinylidene carbonate分类
化学化工引用本文复制引用
赵岩,刘浩,易宗琳,李莉,谢莉婧,苏方远..FEC与VC在锂离子电池石墨负极界面行为研究[J].储能科学与技术,2025,14(9):3249-3258,10.基金项目
国家自然科学基金(22379157),所创新基金基础研究项目(SCJC-XCL-2023-13,SCJCXCL-2023-10). （22379157）
