Lithium ion battery diaphragm with high wettability and high flame retardance and preparation method thereof

The invention discloses a lithium ion battery diaphragm with high wettability and high flame retardance and a preparation method thereof, the lithium ion battery diaphragm comprises a base film and a coating layer, and the coating layer comprises the following components: SnO2 nanotube coated polydopamine derived porous carbon coated KHCO3, a dispersing agent, a thickening agent, an adhesive and a wetting agent. According to the invention, SnO2 nanotube-poly-dopamine-derived porous carbon-KHCO3 is introduced on the surface of the battery diaphragm, and the mechanical strength and thermal shrinkage performance of the prepared diaphragm are improved by using the excellent performance of the SnO2 nanotube-poly-dopamine-derived porous carbon-KHCO3, the mutual crosslinking among different nanotubes and the synergistic effect among multiple layers of components of the SnO2 nanotube-poly-dopamine-derived porous carbon-KHCO3; wherein the polydopamine-derived porous carbon enhances the conductivity, is beneficial to e