Fluorinated Hybrid Diluent Modulated Electrolyte for Wide-Temperature 508.5 Wh kg–1 Lithium Metal Batteries

Rational electrolyte design is the key to high-energy-density and wide-temperature lithium metal batteries. However, sluggish ion transport, unstable interfaces, and electrode deterioration remain critical challenges, especially at low temperatures. Herein, we proposed a localized high-concentration electrolyte with fluoroether hybrid diluent to enable structural diffusion-dominated Li+ transport. Its tailored solvation structure forms compact and dynamically coordinated ion aggregates, which enhance Li+ mobility by shortening the path and improving conductivity, while promoting the formation of robust inorganic-rich passivation layers and improving the interface and cycling stability. Obtained lithium metal batteries paired with high-voltage cathodes demonstrate excellent performance retaining 85.9% capacity after 500 cycles at room temperature and 95.3% after 200 cycles at −20 °C. A 5.81 Ah pouch cell delivers an energy density of 508.5 Wh kg–1 with 80.9% capacity retention after 100 cycles and maintains 92.9% of its capacity at −20 °C, which highlights a scalable electrolyte design strategy for next-generation, high-performance batteries under extreme conditions.