Fluorine-rich-enabled interfacial stabilization in in-situ polymerized electrolytes for all-solid-state lithium metal batteries

Although in-situ polymerization has been applied to optimize interfacial contact in all-solid-state metal batteries (ASSLMBs), the interfacial stability largely relies on the type and structure of the monomers, which limits the full utilization of this strategy. Herein, this work addresses this problem by achieving fluorine-rich-enabled interfacial stabilization through the rational integration of a fluorinated monomer into an in-situ thermally initiated free-radical polymerized solid electrolyte. The fluorinated polymer electrolyte promotes the construction of a stable and LiF-rich Solid Electrolyte Interphase (SEI). Such robust SEI serves to suppress side reactions effectively and regulates lithium deposition behavior, leading to a markedly improved electrochemical stability. Consequently, obtained solid electrolyte gets a higher ionic conductivity (1.26 × 10−4 S cm−1), a broader electrochemical window (4.97 V) and a higher Li+ transference number (0.63). Besides, Li||Li symmetric cells exhibit stable cycling beyond 1400 h at 0.2 mA cm−2/0.2 mAh cm−2 and Li||LiFePO₄ (LFP) full cells can retain 92.04% of their initial capacity after 200 cycles at 1 C. Furthermore, pouch cells demonstrate reliable cycling performance, highlighting the practical applicability of this strategy.