Preparation method of composite coated lithium ion battery polyethylene diaphragm

The invention discloses a preparation method of a composite coated lithium ion battery polyethylene diaphragm. The aramid nanofiber, the polydopamine and the boehmite are used as a coating main body, and excellent thermal stability and rich polar groups are utilized, so that the problems of poor thermal stability and poor lyophilic property to electrolyte of the polyethylene diaphragm are solved. Meanwhile, PDA is adopted for modifying PE, and the problem that the surface energy of the PE diaphragm and the surface energy of a coating layer are not matched can be greatly solved. The thermal shrinkage rate, surface wettability, mechanical property and electrochemical property tests verify the influence of the modified diaphragm on physical properties and electrochemical properties. 本发明公开了一种复合涂覆锂离子电池聚乙烯隔膜的制备方法。以芳纶纳米纤维、聚多巴胺和勃姆石为涂覆主体，利用优异的热稳定性以及丰富的极性基团，改善聚乙烯隔膜热稳定性差、对电解质亲液性差的问题。同时采用PDA改性PE，可以大幅改善PE隔膜与涂覆层间表面能不匹配的问题。经热收缩率、表面润湿性、力学性能及电化学性能测试验证改性隔膜对物理性能和电化学性能的影响。