Enhanced Anion‐Coordination Solvation Structure in High‐Voltage Electrolyte Enables Wide‐Temperature and Fast‐Charging Lithium Metal Batteries

Abstract High‐voltage lithium metal batteries (LMBs) have garnered significant attention for their high energy density, but struggle with high‐rate capability and wide‐temperature operation. Balancing high‐temperature interfacial stability with rapid low‐temperature/high‐rate desolvation kinetics remains challenging. This study introduces a polyanion‐synergized weakly solvating electrolyte strategy. Using fluoroethylene carbonate (FEC) and ethyl methyl carbonate (EMC) as weakly solvating solvents, a ternary anion system (PF 6 − /TFSI − /BOB − ) modulates the solvation structure. This results in an anion‐enhanced solvation structure enriched with contact ion pairs (CIPs) and ion aggregates (AGGs), which significantly reduces the Li⁺ desolvation energy barrier and enhances Li + transport kinetics. Moreover, the electrolyte constructs a stable electrode/electrolyte interphase (EEI) enriched with inorganic components such as LiF, Li 2 S, Li 2 SO x , Li 3 N, and Li x BO y , providing excellent mechanical and thermal stability. Additionally, LiBOB neutralizes harmful HF, further enhancing electrolyte stability. As a result, the Li||NCM811 battery demonstrates excellent cycling stability across a wide temperature range of ‐10‐60 °C at a high cutoff voltage of 4.6 V and achieves stable charge/discharge performance at a high rate of 5C. A 2.7 Ah pouch cell (359 Wh kg −1 ) also shows excellent cycling stability. This work provides novel perspectives on high‐voltage electrolyte engineering and propels LMBs toward expanded practical applications.