In Situ Constructing of LiF‐Organic Composite SEI for Ultra‐Stable Li Anodes in Li‐Cl 2 Batteries

ABSTRACT The escalating demand for high‐energy‐density storage has intensified research on Li‐Cl 2 batteries, which exhibit ultrahigh energy density but suffer from rapid failure due to the poor ionic conductivity and mechanical fragility of naturally formed LiCl interphases on Li metal. Here, we design an organic–inorganic hybrid protective layer (Li 3 Sb/LiF/PVDF, denoted as LSLP@Li) via in situ interfacial engineering. This designed layer effectively isolates the Li anode from corrosive SOCl 2 electrolyte and suppresses parasitic reactions. The synergistic Li 3 Sb/LiF phase ensures high ionic conductivity and guides uniform Li deposition, while the flexible PVDF matrix accommodates cycling‐induced volumetric strain. As a result, the LSLP@Li anode maintains structural integrity for over 48 h in corrosive electrolyte (<2 h for bare Li), enabling Li‐Cl 2 batteries to maintain over 400 cycles at 1000 mA g −1 . The study advances the understanding of naturally formed LiCl layer on SOCl 2 ‐based battery and provide valuable strategy to achieve the interfacial stability.