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

Abstract 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||LiNi 0.8 Co 0.1 Mn 0.1 O 2 (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.