Tang Shunhao, Xiao Wei, Qiao Qingdong, Li Ying
With the advancement of technology,the demand for new energy is increasing day by day,especially for lithium-ion batteries.Due to the easy thermal runaway of lithium-ion batteries,there are many safety hazards,which greatly limits the wide application of lithium-ion batteries.Lithium-ion batteries usually consist of positive electrode,negative electrode,ion separator,electrolyte,and aluminum-plastic film.Among them,the presence of the ion separator separates the anode and cathode,while providing an ion transport channel between the cathode and anode.It determines whether the battery is safe and enabling the functions related to charging and discharging to be realized.At present,the common separator material is polyolefin compounds,but these materials have some significant defects that cannot be ignored.Improvements can be made by modifying existing separators or replacing traditional materials with alternative ones to achieve better performance.This paper focused on the main safety issues associated with conventional lithium-ion battery separators (polyethylene membrane,polypropylene membrane,double-layer polyolefin membrane,and three-layer polyolefin membrane),and put forward several methods to address these safety concerns,namely,dry method,wet method,electrospinning method and their modification methods.At the same time,three new separator materials,PVDF-HFP,PI and cellulose,and their modification methods were proposed.Finally,the development trends of lithium-ion battery separators were discussed.
