Polymer Separators and Solid Polymer Electrolytes for Lithium-Metal Batteries

Developing high-performance and high-safety lithium-metal batteries (LMBs) is of importance to meet the growing demands of next-generation energy storage. Leveraging the high structural tunability and chemical versatility of polymer materials, rational design strategies for advanced polymer separators and solid polymer electrolytes have attracted considerable attention, showing great promise for enabling LMBs with enhanced safety and reliability. This review summarizes previously reported design strategies for these key components, highlighting how molecular and microstructural engineering of polymers can address core challenges such as lithium dendrite growth and thermal instability. Recent advancements on the polymer design strategies were systematically analyzed with an emphasis on the underlying mechanisms in regulating ion transport, suppressing dendrite growth, and enhancing operation safety. Finally, current challenges and future perspectives are discussed, which aim at deepening the insight into rational design of polymer separators and solid polymer electrolyte toward further advancement and practical applications of LMBs.