Method for making polyimide microporous separator

A method for making a polyimide microporous separator comprising:

• using a flexible monomer to prepare a soluble polyimide by a one-step method, and forming a polyimide liquid solution, comprising:
• in a protective gas, adding a dianhydride monomer and a diamine monomer into an organic solvent to form a mixed liquid;
• stirring the mixed liquid to dissolve the dianhydride monomer and the diamine monomer in the organic solvent, and after that, adding a catalyst to fully react at 160° C. to 200° C. to form a polyimide;
• and
• dissolving the polyimide in an organic solvent to form the polyimide liquid solution;
• providing an inorganic template being inorganic nanoparticles, and surface treating the inorganic template with a surface treatment agent in an organic solvent to dissolve the inorganic template in the organic solvent, thereby forming an inorganic template liquid dispersion;
• mixing the polyimide liquid solution with the inorganic template liquid dispersion and ultrasonically agitating to form a film forming liquid;
• coating the film forming liquid on a surface of a substrate and drying to form an organic-inorganic composite film;
• and
• disposing the organic-inorganic composite film into a liquid solution of a template removing agent, the inorganic template in the organic-inorganic composite film reacting with the template removing agent to remove the inorganic template from the organic-inorganic composite film, thereby achieving the polyimide microporous separator.