Recent Advances in Polymer-Based Separators for Lithium-Ion Batteries: A Review
Lithium-ion batteries (LIBs) have emerged as dominant energy storage systems due to their high energy density, long cycle life, and relatively high safety. As a critical component of LIBs, separators are critical for maintaining battery safety and electrochemical stability. This review systematically summarizes recent advances in polymer-based separators for LIBs. First, the basic structure and working principles of LIBs are introduced, together with the major performance requirements of separators, including electrical insulation, porosity, electrochemical stability, electrolyte wettability, mechanical strength, and thermal stability. Subsequently, the main modification strategies for separators are discussed, including inorganic composite modification, organic composite modification, the development of novel separator materials, and advanced binder design. These approaches effectively address the inherent limitations of conventional polyolefin separators, particularly their low thermal stability and poor electrolyte affinity. Furthermore, functionalized separators designed to address critical issues such as transition-metal dissolution and lithium dendrite growth are systematically reviewed. Finally, future development trends of separator technology are discussed, emphasizing multifunctionality, high safety, and targeted structural design. The development of advanced polymer separators is expected to provide important material support for high-performance lithium-ion batteries in electric vehicles and large-scale energy-storage systems.