High-efficiency fabrication of gel polymer electrolyte by click chemistry for long-cycling lithium metal batteries

Herein, we report a mild thiol-ene click chemistry strategy for the in-situ fabrication of a three-dimensional cross-linked gel polymer electrolyte (PAE) on the electrode surface within 5 min under UV initiation. The PAE, formed by the polymerization of pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) and divinyl adipate (ACDE), minimizes the potential adverse effects of residual monomers or by-products on battery performance. Benefiting from the compact cross-linked network, the obtained gel electrolyte exhibits an ionic conductivity of 0.536 mS cm−1at room temperature, a Li+ transference number of 0.45, and an initial decomposition temperature above 200 °C. In addition, the PAE effectively confines the liquid components and forms a stable organic-inorganic composite interface, which promotes stable interfacial kinetics and long-term cycling of LiFeP₄-based cells. As a result, Li||Li symmetric cells incorporating PAE deliver stable cycling for over 2700 h, while Li||LiFePO4cells retain 94.6% of their capacity after 800 cycles. This work provides a rapid and efficient route for constructing high-performance gel polymer electrolytes and demonstrates strong potential for the scalable fabrication of quasi-solid-state lithium metal batteries.