电解质
溶剂化
锂(药物)
碳酸二乙酯
离子液体
碳酸乙烯酯
化学工程
无机化学
化学
六氟磷酸盐
溶剂
物理化学
有机化学
电极
催化作用
内分泌学
工程类
医学
作者
Hailemariam Kassa Bezabh,Shuo-Feng Chiu,Teklay Mezgebe Hagos,Meng‐Che Tsai,Yosef Nikodimos,Haylay Ghidey Redda,Wei‐Nien Su,Bing‐Joe Hwang
标识
DOI:10.1016/j.jpowsour.2021.229760
摘要
Developing electrolytes with a higher oxidation potential is essential to the performance of lithium-ion batteries (LIBs). Fluorine-containing solvent (1, 1, 2, 2-tetrafluoroethyl-2, 2, 3, 3-tetrafluoropropyl ether (TTE)) is a promising candidate for high-voltage use; however, its weak interaction with lithium hexafluorophosphate (LiPF6) containing electrolyte results in phase separation and causes concerns in practical applications. In this work, ethyl methyl carbonate (EMC) is selected to resolve the phase separation. The solvation structure, oxidation stability, and transport property of 1 M LiPF6 in fluoroethylene carbonate (FEC)/TTE and FEC/TTE/EMC (3:7 and 3:5:2 by vol., respectively) are investigated. The solvation energy of TTE in LiPF6 can be greatly increased by the inclusion of EMC and achieve improved thermodynamic stability. Upon adding EMC, the solvation structure is altered from Li+(FEC)2(PF6−) to Li+(FEC)(EMC)(PF6−) and confirmed by the Raman spectroscopy result. The transference number of Li+ in the improved electrolyte also evidently increases, as confirmed both theoretically and experimentally. Besides, 1 M LiPF6 in EFC/TTE/EMC (3:5: 2 by vol.) exhibits high oxidation potential ~ 5.31 V (vs. Li/Li+) and significantly enhances the transference number of Li+. This work offers a fluorine-containing electrolyte with a stable phase and high oxidation potential for LIB's practical application.
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