A New Strategy for Sulfone-Containing Electrolytes Design Enabling Long Cycling High-Voltage Lithium-Ion Batteries

High-energy-density lithium-ion batteries (LIBs) face critical challenges due to the lack of electrolyte solvents that can achieve dual-interfaces stability. Although ethyl mesylate (EM)-based sulfone electrolytes are compatible with high-voltage cathodes, their high viscosity and the tendency of EM's reactive sulfonate ester group to decompose at graphite (Gr) anodes limit their broad applications. Here, a novel electrolyte approach is introduced that uses single co-solvent ethyl acetate (EA), methyl propionate (MP), or methyl butyrate (MB) in an EM-based electrolyte to modulate solvation and interfacial chemistry bypassing the high-concentration lithium salt. These co-solvents disrupt the EM-dominated solvation structure, diminishing the EM-Li+ interaction, allowing more lithium oxalyldifluoroborate (LiODFB) to integrate into the primary Li+ solvation shell and facilitate the formation of stable electrode interphases. The designed electrolytes ensure high-voltage stability while solving the incompatibility of sulfone solvent EM at the graphite anode. Consequently, a 4.5 V Gr||LiNi0.8Co0.1Mn0.1O2 (NCM811) full cell demonstrates outstanding cycling stability, retaining 89.1% capacity after 500 cycles at 1 C rate, with an average coulombic efficiency of 99.92%. This innovative strategy offers a practical approach for utilizing sulfone solvents in next-generation high-voltage lithium-ion batteries.