Recent Progress of High Safety Separator for Lithium-Ion Battery

With the rapid increase in quantity and expanded application range of lithium-ion batteries, their safety problems are becoming much more prominent, and it is urgent to take corresponding safety measures to improve battery safety. Generally, the improved safety of lithium-ion battery materials will reduce the risk of thermal runaway explosion. The separator is a key component of lithium-ion batteries. It plays a crucial role in battery safety, serving as one of the most effective measures against internal short circuits.Separator failure is a direct cause of the thermal runaway and can be specifically divided into three categories: puncture, melting, and thermal shrinkage. The requirements for an ideal lithium-ion battery separator have a synergistic effect on the electrochemical performance, safety, and scalability of lithium-ion batteries. Focus on the separator, this review summaries the mechanism of separator in thermal runaway process, and reports the recent progress of high safety separator from the perspective of material preparation.