Composite diaphragm and preparation method and use thereof

The invention relates to a composite membrane and a preparation method and use thereof. The composite membrane comprises a base film and a selective control coating arranged on the surface of the basefilm. The selective control coating is composed of an inorganic component and an organic component distributed on the surface of the inorganic component particles. The inorganic component and the organic component are connected through any one of a chemical bond, a hydrogen bond and the van der Waals force, or a combination of at least two. According to the invention, the composite membrane takesa factor affecting battery performances (lithium ion conductivity, electrode interface, self-structural stability, electrolyte stability and the like) as a starting point; the composition and morphology of the membrane coating is selectively controlled and designed; and the conventional properties, such as mechanical strength, thermal stability, electrode interface stability, electrolyte wettability, of the acquired membr