LAUSR

Lithium-ion batteries (LIBs) are momentous energy storage devices which have been rapidly developed due to their high energy density, long lifetime, and low self-discharge rate. However, the frequent occurrence of fire accidents in laptops, electric vehicles, and mobile phones caused by thermal runaway of the inside batteries, constantly reminds us of the urgency in pursuing high-safety LIBs with high performance. To this end, our review surveys the state-of-the-art developments of high-thermal-stable separators for highly safe LIBs with excellent electrochemical performance. Firstly, we introduce the basic properties of separators (e.g., thickness, porosity, pore size, wettability, mechanical strength, and thermal stability) in constructing the commercialized LIBs. Secondly, we discuss the working mechanisms of advanced separators with different melting points acting in the thermal runaway stage for improving battery safety. Thirdly, rational design strategies for constructing high-thermal-stable separators for LIBs with high safety are summarized and discussed, including graft modification, blend modification, and multilayer composite modification strategies. Finally, we highlight the current obstacles and future research directions in the field of high-thermal-stable separators. We envision that these design ideas expect to be applied to other types of high-thermal-stable energy storage systems working under extreme conditions.