Composite diaphragm, preparation method thereof and lithium ion battery

The invention belongs to the technical field of batteries, and particularly relates to a composite diaphragm which comprises a base membrane subjected to corona treatment, a high-temperature-resistantceramic coating is arranged on one surface of the base membrane, and water-based bonding layers are arranged on the other surface of the base membrane and the surface of the high-temperature-resistant ceramic coating; and the high-temperature-resistant ceramic coating comprises a ceramic material, a high-temperature-resistant binder, a dispersing agent, a thickening agent, a wetting agent and deionized water. In addition, the invention also provides a preparation method of the composite diaphragm and a lithium ion battery containing the composite diaphragm. Compared with the prior art, the composite diaphragm has the advantage that the cycle performance and the safety performance of the lithium ion battery can be improved on the premise of ensuring the air permeability. 本发明属于电池技术领域，尤其涉及一种复合隔膜，包括经过电晕处理的基膜，所述基膜的一面设