Lithium-ion batteries polymeric separators: A comprehensive review

Polymeric separators are essential components of lithium-ion batteries (LIBs), serving the critical function of physically isolating electrodes while facilitating lithium-ion transport. This comprehensive review examines recent advances in polymeric separator materials, design strategies, and manufacturing techniques, with emphasis on their role in enhancing battery performance, safety, and sustainability. We discuss traditional polyolefin-based separators and highlight emerging alternatives including composite materials, nanofiber-based systems, and functionally modified membranes. Special attention is given to key performance metrics such as ionic conductivity, thermal stability, mechanical robustness, and dendrite suppression. Additionally, this review addresses the critical challenge of thermal runaway mitigation and explores sustainable, environmentally-friendly separator technologies. Recent breakthroughs in manufacturing techniques, including electrospinning, phase inversion, and advanced additive manufacturing approaches, are thoroughly analyzed. The review concludes by identifying remaining challenges and providing future perspectives for next-generation separator technologies essential for enabling safe, high-energy-density lithium-ion batteries for electric vehicles, stationary energy storage, and portable electronics.