Li Liang, Ren Kaixiang, Xie Wenjun, Yu Qi, Wu Shilin, Li Hai-Wen, Yao Meng, Jiang Zhipeng, Li Yongtao
School of Materials Science and Engineering, Anhui University of Technology Maanshan 243002 China
School of Advanced Energy, Sun Yat-sen University Shenzhen 518107 China.
Chem Sci. 2025 Mar 31;16(18):7981-7988. doi: 10.1039/d5sc01495f. eCollection 2025 May 7.
The design of novel electrolytes is crucial for ensuring the practical application of high-voltage lithium metal batteries (LMBs). Weakly solvating electrolytes (WSEs), achieved by reducing the solvent's solvation ability, have been shown to improve the cycling stability of LMBs. However, the internal relationship between the weaker solvation effects of the solvent and battery performance is not well understood. In this work, we design a series of solvents with different solvation effects, using 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL) as base skeletons, and systematically examine the physicochemical and electrochemical properties of these WSEs. Our results show that the performance of WSEs is not solely determined by the solvation structure but is also influenced by the intrinsic reactivity of the solvent. Guided by this principle, we develop a high-performance electrolyte based on 2-methoxy-1,3-dioxolane (2-MeO DOL), which exhibits both weak solvation effects and low reactivity. This electrolyte enables stable cycling of Li-Cu half cells for over 250 cycles with a coulombic efficiency of 99.3% and demonstrates stable cycling in Li-LiNiCoMnO (NCM811) full cells at a 4.4 V cut-off voltage under practical conditions. This study offers critical insights for the design and high-throughput screening of next-generation high-performance WSEs for LMBs.
新型电解质的设计对于确保高压锂金属电池（LMBs）的实际应用至关重要。通过降低溶剂的溶剂化能力获得的弱溶剂化电解质（WSEs）已被证明可以提高LMBs的循环稳定性。然而，溶剂较弱的溶剂化效应与电池性能之间的内在关系尚未得到充分理解。在这项工作中，我们以1,2 - 二甲氧基乙烷（DME）和1,3 - 二氧戊环（DOL）为基础骨架，设计了一系列具有不同溶剂化效应的溶剂，并系统地研究了这些WSEs的物理化学和电化学性质。我们的结果表明，WSEs的性能不仅取决于溶剂化结构，还受到溶剂固有反应性的影响。基于这一原理，我们开发了一种基于2 - 甲氧基 - 1,3 - 二氧戊环（2 - MeO DOL）的高性能电解质，它既表现出弱溶剂化效应又具有低反应性。这种电解质能使Li - Cu半电池稳定循环超过250次，库仑效率为99.3%，并在实际条件下4.4 V截止电压的Li - LiNiCoMnO（NCM811）全电池中展示出稳定循环。这项研究为LMBs下一代高性能WSEs的设计和高通量筛选提供了关键见解。
