Thiol‐Ene Photo Crosslinked PUA‐PUMA‐Based Flexible Gel Polymer Electrolyte for Lithium‐Ion Batteries

Abstract Crosslinked polymer films, formed via sol–gel and UV photocrosslinking, serve as gel polymer electrolytes (GPEs) in lithium‐ion batteries. Combining polyurethane acrylate (PUA), polyurethane methacrylate (PUMA), pentaerythritol tetrakis (3‐mercaptopropionate) (PETMP), and 3‐mercaptopropyl trimetoxysilane (MPTMS) yields flexible membranes, enhancing stability and liquid electrolyte compatibility. The resulting GPE displays higher ionic conductivity (1.46 × 10 −3 S cm −1 ) than Celgrad2500, with PUA‐PUMA's hydrophilicity and PETMP's SH groups preventing leakage. GPPF1, the developed GPE, offers improved ionic conductivity, a stable electrochemical window up to 3.8 V, and heightened safety for versatile energy storage systems.