Zou Jiahang, Yang Hanxu, Wu Shilin, Xiao Zhengquan, Jiang Zhipeng, Shen Wangqiang, Li Yongtao
School of Materials Science and Engineering, Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials of Ministry of Education, Anhui University of Technology, Maanshan 243002, China.
School of Materials Science and Engineering, Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials of Ministry of Education, Anhui University of Technology, Maanshan 243002, China; Key Laboratory of Efficient Conversion and Solid-state Storage of Hydrogen & Electricity of Anhui Province, Maanshan 243002, China.
J Colloid Interface Sci. 2025 Apr;683(Pt 2):281-290. doi: 10.1016/j.jcis.2024.12.102. Epub 2024 Dec 16.
Ether-based electrolytes are known for their high stability with lithium metal anodes (LMAs), but they often exhibit poor high-voltage stability. Structural optimization of ether-based solvent molecules has been proven to effectively broaden the electrochemical window of these electrolytes, yet the optimization rules within cyclic ethers remain unclear. Herein, we investigate the impact of methyl substitution positions on the molecular properties of 1,3-dioxolane (DOL), a commonly used cyclic ether. The results show that the introduction of methyl groups can effectively inhibit the ring-opening polymerization of DOL. Besides, 4-methyl-1,3-dioxolane (4-Me DOL), with larger steric hindrance compared to 2-methyl-1,3-dioxolane (2-Me DOL), exhibits weaker solvation ability, favoring the formation of anion-rich inner solvation sheath layers and anion-derived interfaces. Even at conventional concentrations, 1 M LiFSI in 4-Me DOL (LiFSI/4-Me DOL) electrolyte demonstrates good LMA stability and an expanded electrochemical window up to 4.6 V. The Li-LiNiCoMnO (NCM523) cell using LiFSI/4-Me DOL could stably cycle over 300 times. This work reveals a new design principle for solvent molecules.
醚基电解质以其与锂金属阳极（LMA）的高稳定性而闻名，但它们通常表现出较差的高压稳定性。已证明对醚基溶剂分子进行结构优化可有效拓宽这些电解质的电化学窗口，但环状醚中的优化规则仍不明确。在此，我们研究了甲基取代位置对常用环状醚1,3 - 二氧戊环（DOL）分子性质的影响。结果表明，甲基的引入可有效抑制DOL的开环聚合。此外，与2 - 甲基 - 1,3 - 二氧戊环（2 - Me DOL）相比，空间位阻更大的4 - 甲基 - 1,3 - 二氧戊环（4 - Me DOL）表现出较弱的溶剂化能力，有利于形成富含阴离子的内溶剂化鞘层和阴离子衍生界面。即使在常规浓度下，4 - Me DOL中的1 M LiFSI（LiFSI/4 - Me DOL）电解质也表现出良好的LMA稳定性和高达4.6 V的扩展电化学窗口。使用LiFSI/4 - Me DOL的锂 - 锂镍钴锰氧化物（NCM523）电池可稳定循环300多次。这项工作揭示了溶剂分子的一种新设计原则。
