Targeted Functionalization of Cyclic Ether Solvents for Controlled Reactivity in High-Voltage Lithium Metal Batteries

作者：Yan Zhao, Tianhong Zhou, Dominika Baster, Mario El Kazzi, Jang Wook Choi, Ali Coşkun · 发表于：ACS Energy Letters · 年份：2023 · DOI：10.1021/acsenergylett.3c01004 · 被引用次数：90 · 研究领域：Advanced Battery Materials and Technologies、Advancements in Battery Materials、Advanced Battery Technologies Research

Understanding the degradation pathways and reactivity of electrolytes is the key to address the shortcomings of conventional electrolytes and to develop new electrolytes for high-voltage lithium metal batteries (LMBs). Accordingly, while 1,3-dioxolane (DOL) exhibits desired features such as good compatibility with Li metal, low viscosity, and high ionic conductivity, it suffers from poor oxidation stability, mainly from its ring-opening polymerization. In an effort to control the reactivity of DOL by tuning its electronic properties, we introduced methyl and trifluoromethyl groups to the ethyl moiety of DOL and developed 4-methyl-1,3-dioxolane (MDOL) and 4-(trifluoromethyl)-1,3-dioxolane (TFDOL) as solvents, respectively. Whereas the MDOL-based electrolyte exhibited serious side reactions toward metallic Li, the TFDOL-based electrolyte showed oxidation stability up to 5.0 V. Moreover, the inorganic-rich solid electrolyte interphase induced by the weak solvation power of TFDOL along with high oxidation stability enabled a robust cycling stability in a Li|NCM811 full cell (20 μm Li foil, N/P ratio of 2.5).