Application of Polymer Electrolytes Prepared by Ultraviolet Polymerization in Various Lithium Metal Battery Systems

Lithium metal batteries (LMBs) are poised to play a pivotal role in addressing global energy storage needs, owing to their high energy density, excellent charge–discharge efficiency, and relatively benign environmental profile, compared to other battery technologies. However, the widespread adoption of LMBs is hampered by limitations associated with conventional liquid electrolytes, including flammability, leakage, and inducing lithium (Li) dendrite formation, which compromise battery safety and cycling life. Polymer electrolytes offer a compelling solution to these challenges and thus have attracted wide attention due to their good electrode compatibility, nontoxicity, and flexible properties. Among various polymer electrolyte fabrication techniques, ultraviolet (UV) polymerization stands out because of its simplicity, rapid processing, cost-effectiveness, and scalability. This review first offers the unique advantages of these UV-curing polymer electrolytes compared to traditional liquid electrolytes. In addition, the UV polymerization mechanisms are discussed, emphasizing the critical role of photoinitiators and the technique’s advantages over traditional methods. Moreover, a comprehensive analysis of the recent advancements about the UV-curing polymer electrolytes with different monomer precursors in various LMBs (conventional cathode-based LMBs, Li–air batteries, and Li–sulfur (S) batteries) is summarized in detail. Finally, future research directions are outlined, emphasizing the potential of UV polymerization to drive innovation in Li metal battery technologies and accelerate their further development.