Separators in Lithium-ion (Li-ion) batteries literally separate the anode and cathode to prevent a short circuit. Modern separator technology also contributes to a cell’s thermal stability and safety. Separators impact several battery performance parameters, including cycle life, energy and power density, and safety.
Furthermore, the component–structure–performance relationship of separators is summarized, and the impact of separator compositions and structures on the safety of LIBs is emphasized. In addition, the future challenges and perspectives of separators are provided for building high safety rechargeable lithium batteries.
Ceramic-coated separators and high melting point polymer materials offer some improvement in thermal stability and abuse tolerance for lithium-ion cell separators but, in general, more evaluation is needed to quantify the safety impact of these new separators.
Separators contribute to the safety and reliability of Li-ion batteries. When comparing various separator materials, there are numerous specifications, including chemical stability, mechanical strength, wettability, thermal performance and porosity, and pore size.
There are numerous safety and performance standards for Li-ions in specific applications such as automotive systems and consumer devices. But only one for battery cell separator safety: UL 2591, Outline of Investigation for Battery Cell Separators.
The separator plays the pivotal role in normal LIBs and SIBs device and there is a close relationship between separator and battery safety , . The separator acts as a physical barrier to insulate cathode and anode from direct contact and accommodate electrolyte to facilitate ions shuttle inside the battery.