New progress in fluorine-coordinated electrolyte technology, lithium-metal battery energy density reaches 700Wh/kg

    Lithium‑metal batteries promise energy densities far exceeding those of today’s lithium‑ion batteries, but their practical deployment is hindered by electrolyte limitations. Conventional electrolytes rely on Li–O coordination, which results in high desolvation energy barriers, poor low‑temperature performance and limited solubility of lithium salts in fluorinated solvents. Here we report a class of hydrofluorocarbon electrolytes based on Li–F coordination, which enables high lithium salt solubility (>2 mol L⁻¹), low viscosity, high oxidative stability (>4.9 V) and exceptional low‑temperature performance. Using 1,3‑difluoropropane (DFP) as the solvent, we demonstrate lithium‑metal pouch cells with energy densities exceeding 700 Wh kg⁻¹ at room temperature and about 400 Wh kg⁻¹ at −50 °C, with stable cycling. This work provides a new design principle for electrolytes that could enable the development of next‑generation high‑energy‑density and low‑temperature batteries.