Ionization‐Targeted Modulation Enables Fast‐Charging and High‐Temperature Lithium‐Metal Batteries

Abstract Conventional carbonate electrolytes are plagued by high desolvation energy and poor lithium‐metal compatibility, severely limiting the practical viability of lithium‐metal batteries, particularly under demanding high‐temperature and fast‐charging scenarios. In this work, an ionization‐targeted modulation strategy is proposed that reshapes lithium ions solvation structures and improves electrolyte properties. By incorporating 2‐methyl‐4‐fluorobenzyl ether (TFBn) as a functional solvent, the fluorinated benzene ring induces pronounced molecular polarization through its ionization effect, effectively weakening the Li ⁺ −solvent interactions and significantly lowering the desolvation energy barrier. Simultaneously, the steric hindrance of the methyl group prevents carbonate solvent molecules from entering the inner solvation sheath, promoting preferential PF ₆ − coordination. This anion‐dominated solvation structure facilitates the formation of a robust inorganic‐rich interphase with high LiF content, significantly enhancing interfacial stability. Moreover, the high thermal stability and rigid benzene ring structure of TFBn effectively suppress electrolyte decomposition and interfacial degradation at elevated temperatures. The optimized electrolyte enables Li||LiNi _0.8 Co _0.1 Mn _0.1 O ₂ cells to retain 85% of its capacity after 300 cycles at 5 C and maintains 75% capacity after 200 cycles even under harsh conditions (60 °C, 5 C). This work establishes a molecular engineering paradigm for designing high‐performance carbonate electrolytes in next‐generation lithium‐metal batteries.