From lab to industry: High-safety separators for lithium-ion/-metal batteries

Rechargeable lithium-ion and lithium-metal batteries have achieved remarkable progress, yet frequent battery accidents demand urgent attention. The separator, which acts as both an electrical barrier and an ion transport medium between electrodes, fundamentally governs ionic kinetics, rate performance, and, most importantly, battery safety. Developing functional separators that ensure continuous and safe battery operation is therefore critical. This review systematically summarizes recent progress in high-safety separators for lithium-ion and lithium-metal batteries, spanning from laboratory research to industrial applications. Various safety concerns—chemical crosstalk and internal short circuits—are discussed in detail. Key performance requirements for high-safety separators, including mechanical strength, thermal conductivity, heat resistance, anti-dendrite properties, and crosstalk resistance, are highlighted. The industrial preparation processes and the associated challenges are also discussed, with an emphasis on the importance of close collaboration between academia and industry. Finally, we present the key challenges and future perspectives for the development of high-safety separators.