Dual-Layered Organo-Fluorinated Hetero-Interphase: A Robust Shield for Ultra-Stable Lithium Metal Batteries
Lithium metal anodes (LMAs) are pivotal for next-generation high-energy batteries, yet their commercialization is hindered by dendrite growth and unstable solid electrolyte interphase (SEI). Here, we report a dual-layered artificial SEI (ASEI) comprising an inner LiF-rich inorganic layer and an outer perfluoropolyether (PFOE) organic layer, fabricated via a scalable roll-pressing technique. The LiF-rich layer lowers Li-ion diffusion barriers and provides mechanical robustness, while the PFOE layer chemically stabilizes the interface against electrolyte oxidation. Symmetric cells with PFOE-LiF@Li anodes achieve over 1400 h of stable cycling at 30 mA cm−2 and 5 mAh cm−2. Full cells paired with LiFePO4 cathodes deliver 350 cycles at 1 C and over 550 cycles at 2 C with high capacity retention and Coulombic efficiency. This work establishes a design principle for interfacial engineering, combining inorganic rigidity with organic functionality, and offers a promising route for practical LMBs.