Fluorine-functionalized MOF-based solid electrolyte with stable interphase and rapid Li+ transport for ultra-long cycling lithium metal battery

Developing high-energy-density lithium metal battery is essential for next-generation energy storage system, but poor interfacial stability and sluggish ion transport kinetics pose significant challenges. Herein, fluorine-functionalized metal–organic frameworks (MOFs) is developed and utilized as solid-state electrolyte to realize the target of efficient, long-life lithium metal battery. This fluorine-modified MOF electrolyte boosts in situ formation of LiF-rich solid electrolyte interphase (SEI), which is greatly benefit for uniform Li + deposition and lithium dendrite inhibition. The electron localization function (ELF) and nudged elastic band (NEB) calculation reveal that electron-withdrawing F group can modulate the electron distribution along MOF porous channels and reduce the energy barrier for Li transport, achieving high ionic conductivity (2.15 × 10 −3  S cm −1 ) and large transfer number (0.76). Consequently, the LiF-rich SEI enables batteries with ultra-long stability over 5000 h under 5 mA cm −2 and long-lifespan over 900 cycles. The COMSOL simulations confirm MIL-53-4F SSEs enable uniform Li deposition and suppress dendrite growth. Impressively, the fluorinated electrolyte illustrates excellent compatibility with LiNi 0.5 Co 0.2 Mn 0.3 O 2 and x Li 2 MnO 3 · (1-x) LiMO 2 high-voltage cathodes, achieving energy density of 164.8 Wh kg −1 . These findings bring valuable insight to develop highly efficient solid-state electrolyte for future long-life lithium metal battery.