Flame-retardant porous polymer film and preparation method thereof

The invention provides a preparation method for a flame-retardant porous polymer film. The method comprises the following steps of: a, dissolving the polymer with an organic solvent and adding a pore-forming agent into the dissolved polymer to obtain emulsion; b, coating the emulsion on a matrix and carrying out drying or extraction treatment on the matrix to obtain a porous polymer-based film; and c, plating an aluminum hydroxide film on the surface of the porous polymer-based film and heating the obtained product to decompose the aluminum hydroxide on the surface of the matrix into aluminum oxide to obtain the flame-retardant porous polymer film. The invention also provides the flame-retardant porous polymer film prepared by the method and a battery containing the same. The flame-retardant porous polymer film prepared by the method of the invention has uniformly dispersed aluminum oxide, so that the obtained flame-retardant porous polymer film has uniform flame retardance and the use safety of the battery i