High safety separators for rechargeable lithium batteries

Lithium-ion batteries (LIBs) are presently dominant mobile power sources due to their high energy density, long lifespan, and low self-discharging rates. The safety of LIBs has been concerned all the time and become the main problem restricting the development of high energy density LIBs. As a significant part of LIBs, the properties of separators have a significant effect on the capacity and performances of batteries and play an important role in the safety of LIBs. In recent years, researchers devoted themselves to the development of various multi-functional safe separators from different views of methods, materials, and practical requirements. In this review, we mainly focus on the recent progress in the development of high-safety separators with high thermal stability, good lithium dendritic resistance, high mechanical strength and novel multifunction for high-safety LIBs and have in-depth discussions regarding the separator’s significant contribution to enhance the safety and performances of the batteries. Furthermore, the future directions and challenges of separators for the next-generation high-safety and high energy density rechargeable lithium batteries are also provided.