Fluorinated Hybrid Diluent Modulated Electrolyte for Wide-Temperature 508.5 Wh kg<sup>–1</sup> Lithium Metal Batteries
Xinyu Zhang, Tingzhou Yang, Zhenheng Huang, Qian Zhang, Shufeng Jia, Jianli Kang, Chunnian He, Naiqin Zhao, Yongguang Zhang, Zhongwei Chen
Abstract
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.