Separator, method for producing the same and electrochemical device including the same
View Patent ↗A separator includes a porous substrate, a porous organic-inorganic coating layer formed on at least one surface of the porous substrate, and an organic coating layer formed on the surface of the organic-inorganic coating layer. The porous organic-inorganic coating layer includes a mixture of inorganic particles and a first binder polymer. The first binder polymer contains a copolymer including (a) a first monomer unit including either at least one amine group or at least one amide group or both in the side chain thereof and (b) a (meth)acrylate having a C 1 -C 14 alkyl group as a second monomer unit. The organic coating layer is formed by dispersing a second binder polymer on the surface of the organic-inorganic coating layer, leaving scattered uncoated areas.
1. A method for producing a separator, comprising:
(S1) preparing a porous substrate;
(S2) dispersing inorganic particles and dissolving a first binder polymer in a solvent to prepare a slurry, the first binder polymer containing a copolymer comprising (a) a first monomer unit comprising either at least one amine group or at least one amide group or both in the side chain thereof and (b) a (meth)acrylate having a C 1 -C 14 alkyl group as a second monomer unit, coating the slurry on at least one surface of the porous substrate, and drying the slurry to form a porous organic-inorganic coating layer; and
(S3) coating a solution of 0.2 to 2.0% by weight of a second binder polymer on the organic-inorganic coating layer, and drying the polymer solution.
2. The method according to claim 1 , wherein the second binder polymer has a solubility parameter different by at least 4 (J/cm 3 ) 0.5 from that of the first binder polymer.
3. The method according to claim 1 , wherein the second binder polymer is selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, polyacrylonitrile, polyvinylpyrrolidone, and mixtures thereof.