Composite diaphragm with adjustable coating, preparation method of composite diaphragm and lithium battery

The invention particularly relates to a coating-adjustable composite diaphragm, a preparation method thereof and a lithium battery, and belongs to the field of lithium battery, the preparation method of the coating-adjustable composite diaphragm provided by the embodiment of the invention comprises the following steps: mixing an inorganic component, an organic component and water, and carrying out high-speed sanding treatment to prepare a coating dispersion liquid; preparing a coating liquid by taking the coating dispersion liquid as a raw material; coating the surface of a base membrane with the coating liquid, and drying to obtain the composite diaphragm with the adjustable and controllable coating; in the coating dispersion liquid, the interaction between the inorganic component and the organic component comprises at least one of chemical bonds, hydrogen bonds and Van der Waals' force; the mass ratio of the inorganic component to the organic component to the water is (0-40): (0-40): (20-100); the lithium b