Recent advances in COF-based separators for rechargeable batteries: Design, properties, and applications

Abstract

Research into novel materials for rechargeable batteries has increased due to the growing need for long-lasting, high-performance energy storage solutions. One of the most important components is the separator, which ensures the safe and quick passage of ions while maintaining system stability. Covalent organic frameworks (COFs) are porous crystalline polymers that exhibit remarkable chemical stability and a variety of topologies. Their applications as components for next-generation battery separators have grown. This study examines current advances in the design, fabrication, and application of COF-based separators in a variety of rechargeable battery systems, including lithium-ion, lithium‑sulfur, sodium‑sulfur, zinc‑sulfur, and zinc‑iodine batteries. We explore into the way COFs' distinct structural properties, such as structured nanochannels, variable functional groups, and high porosity, can improve ion selectivity, electrolyte wettability, and prevent dendritic and polysulphide movement. We also discuss the relationship between structure and property, synthesis methods, and critical performance criteria, with an emphasis on recent developments in COF membrane design. The study concluded by outlining the present problems and offering suggestions for the future development of scalable, highly effective COF-based separators for the upcoming generation of energy storage devices. © 2025 Elsevier Ltd