Recent Progress and Challenge in Metal-Organic Frameworks for Lithium-Sulfur Battery Separators

The separators used in lithium-sulfur (Li-S) batteries play a crucial role in their cycling performance and safety. Current commercial separators lack the ability to efficiently regulate polysulfide shuttling and are prone to thermal runaway at high temperatures. Recent studies have shown that multifunctional separators can boost the electrochemical performance and safety of Li-S batteries. Metal-organic frameworks (MOFs) have emerged as promising materials for modifying separators due to their large specific surface areas and highly ordered tunable nanopores. Herein, this review focuses on the advancements in developing MOFs, their derivatives, and MOFs-based composites as separator coatings to address the shortcomings of Li-S batteries. The mechanisms behind these modified separators, designed to inhibit lithium polysulfide shuttling and lithium dendrite growth, are discussed, emphasizing the relationship between the structure and electrochemical performance. The impact of these modified separator coatings on battery safety is also explored, aiming to design suitable composite films for high-safety Li-S batteries. Furthermore, future perspectives are outlined to guide practical applications and overcome the remaining challenges associated with MOFs-modified separators.