T.L. Chen ‡, A.P. Zhang ‡, X.F. Li, M.Z. Yang, X.X. Ren, L. Song, M.Y. Hou, P.C. Lian * and Z.-S. Wu *

ACS Applied Materials & Interfaces, 2025, accepted.

Lithium-rich manganese oxide (LRMO) is a promising high-energy-density material for high-voltage lithium-ion batteries, but its performance is hindered by interfacial side reactions, transition metal dissolution, and oxygen release. To address these issues, we propose a high-voltage electrolyte strategy that utilizes co-solvent and additive synergy to create stable dual interphases at both the cathode and anode. Specifically, lithium difluoro(oxalato) borate (LiDFOB) additive sacrificially decomposes to form a uniform yet stable cathode-electrolyte interphase (CEI) layer, while co-solvent of bis(2,2,2-trifluoroethyl) carbonate (BTFEC) effectively adjusts the solvation structure and synergistically stabilizes the solid-electrolyte interphase (SEI) on anode, ultimately achieving ultra-high cycle stability and fast charging feasibility. The presence of B-F, LiBxOy species derived from LiDFOB exceptionally stabilizes the fast-ion transfer CEI layer, while the F-rich robust SEI layer inhibits the irregular growth of lithium dendrites. Our electrolyte enables Li||LRMO cells to maintain 95% capacity after 200 cycles at 4.8 V, with a specific capacity of 238 mAh g⁻¹ after 350 cycles at 3 C. Importantly, A 5 Ah graphite||LRMO pouch cell achieves a high energy density of 323 Wh kg⁻¹ with 80.4% capacity retention after 150 cycles, demonstrating its practical application potential.