UV-Cured Interpenetrating Networks of Single-ion Conducting Polymer Electrolytes for Rechargeable Lithium Metal Batteries

We report a facile, in situ method to prepare interpenetrating networks of single-ion conductive polymer electrolytes (IN-SCPEs) for solid-state lithium metal batteries. IN-SCPEs were synthesized by first mixing lithium 4-styrenesulfonyl(trifluoromethylsulfonyl)imide, poly(ethylene glycol) methyl ether acrylate, poly(ethylene glycol) dimethacrylate, and ethylene carbonate to form cross-linked polymer gel networks and then exposing the composite to ultraviolet (UV) light to initiate radical polymerization. The in situ formed interpenetrating polymer networks ensures high mechanical strength and thermal stability of IN-SCPEs, reduces the activation energy of Li+ conduction, and simultaneously improves the room-temperature ionic conductivity (1.9 × 10–4 S cm–1), Li-ion transfer number (0.90) and electrochemical window (5.3 V). The synthesized IN-SCPEs enable dendrite-free cycling of Li metal anode and stable cycling of LiFePO4|IN-SCPEs|Li cell with low polarization at room temperature.