Regulating Li ⁺ Desolvation Kinetics via Dual‐Anion Solvation for High‐Rate Lithium Metal Batteries With Fast‐Charging Capability

ABSTRACT Fast charging of high‐energy lithium metal batteries is fundamentally limited by sluggish Li ⁺ desolvation kinetics and the instability of electrode–electrolyte interfaces under high current densities. Here, an anion‐centric weakly solvating electrolyte is developed via an anion–solvent–anion mutual‐exclusion strategy to simultaneously accelerate Li ⁺ transport and stabilize interfacial chemistry in Li||NCM811 batteries. This cooperative exclusion effect significantly lowers the Li ⁺ desolvation activation energy to ∼34 kJ mol ⁻¹ while maintaining a favorable ion‐pair distribution with minimal aggregation, enabling a high ionic conductivity of ∼2.8 mS cm ⁻¹ . Benefiting from the optimized solvation environment, inorganic‐rich and mechanically robust SEI/CEI layers are formed in situ, facilitating fast interfacial charge transfer and uniform lithium deposition. Consequently, Li||NCM811 cells exhibit outstanding high‐rate performance, delivering high specific capacities at 5 C and 10 C with prolonged cycling stability, demonstrating significant fast‐charging potential. This work elucidates a solvation‐structure‐driven kinetic mechanism critical for fast charging and provides a general electrolyte design paradigm beyond conventional weakly solvating strategies.