Separator for metal secondary batteries

Provided is a separator which can make the electric field on the surface of a negative electrode for a metal secondary battery homogeneous to thereby prevent the formation of dendrites. A porous separator for metal secondary batteries, which has a polymer electrolyte layer formed on the surface layer of at least one main surface of a porous polyimide film. It is preferred that the polymer electrolyte layer is composed of both a polymer electrolyte material which is supported on at least one main surface of the porous polyimide film and a polymer electrolyte material which is supported in voids in a layered region that extends from the main surface. 本发明提供能够使金属二次电池的负极表面的电场均匀从而抑制树枝状晶体产生的隔膜。本发明为金属二次电池用多孔质隔膜，其中，在多孔质聚酰亚胺膜的至少个主表面的表层形成有聚合物电解质层。优选地，所述聚合物电解质层是由所述多孔质聚酰亚胺膜的至少个主表面所担载的聚合物电解质材料、及从该主表面起连续的层状区域中的孔隙内所担载的聚合物电解质材料构成的。