Fluorinated ether electrolyte with controlled solvation structure for high voltage lithium metal batteries

Developing new solvents for lithium metal batteries (LMBs) is crucial due to the incompatibility of conventional carbonate electrolytes and the limited electrochemical windows of ether-based electrolytes. While fluorinated ethers offer improved electrochemical stability, their lithium-ion solvation ability is poor. This research introduces 2,2-dimethoxy-4-(trifluoromethyl)-1,3-dioxolane (DTDL), a novel solvent combining a cyclic fluorinated ether with a linear ether segment to achieve high voltage stability and enhanced lithium-ion solvation. DTDL demonstrates high oxidation stability (up to 5.5 V), a large lithium-ion transference number (0.75), and stable Coulombic efficiency (99.2% after 500 cycles). A LiNi0.8Co0.1Mn0.1O2 full cell using 2 M LIFSI-DTDL electrolyte shows 84% capacity retention after 200 cycles at 0.5 C.

Yan Zhao, Tianhong Zhou, Timur Ashirov, Mario El Kazzi, Claudia Cancellieri, Lars P. H. Jeurgens, Jang Wook Choi, Ali Coskun