Separator, method for producing the same and electrochemical device including the same

Abstract

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-Calkyl 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. The porous organic-inorganic coating layer of the separator has a high packing density, enabling the fabrication of a thin battery in an easy manner without losing stability. The porous organic-inorganic coating layer has good ability to bind to the porous substrate, which prevents the inorganic particles from separating from the porous organic-inorganic coating layer. In addition, the organic coating layer enhances the bindability of the separator to an electrode without a substantial increase in resistance.