γ ‐Valerolactone‐Based Anion‐Dominated Loose Solvation Electrolyte Enables Stable Lithium Metal Batteries from −60°C to 100°C

ABSTRACT Integrating high‐nickel cathodes with lithium metal anodes enables ultrahigh‐energy‐density batteries but remains challenged by electrolyte instability under extreme temperatures. Here, we design an anion‐dominated loose solvation structure, where fluorine‐rich weak solvents occupy coordination sites. γ ‐Valerolactone (GVL) serves as the primary solvent, assisted by two weakly coordinating co‐solvents: difluoroethylene carbonate (DFEC) to modulate solvation and ethyl trifluoroacetate (ETFA) to reduce viscosity and freezing point. This balanced solvation environment enhances ionic transport, interfacial stability, and desolvation kinetics. Consequently, Li||NCM811 cells deliver stable cycling at 100°C, exceeding 90 cycles, negligible capacity loss at −40°C, and 90.4 mAh g −1 at −60°C. Full cells (N/P ≈ 1.8) retain 90.3% capacity after 130 cycles. This work offers a viable solvation design for high‐voltage lithium metal batteries operating across extreme temperatures.