| abstract |
The organic / inorganic composite separation membrane includes a porous substrate having pores; and a porous active layer coated on at least one surface of the porous substrate and containing a mixture of inorganic particles and a binder polymer. The porous active layer has a composition morphological heterogeneity in the thickness direction in which the content ratio of the binder polymer / inorganic particles existing on the surface is larger than the content ratio of the binder polymer / inorganic particles existing inside. (Heterogeneity). The organic / inorganic composite separation membrane introduces a porous active layer having a heterogeneous morphology in which the content ratio of the binder polymer / inorganic particles in the surface layer is larger than the internal content ratio on the porous substrate having pores. Thus, the resistance of the porous active layer to peeling and scratching can be increased, and the lamination characteristics with the electrode can be improved. As a result, the problem that the inorganic particles in the porous active layer fall off during the assembly process of the electrochemical device can be improved, so that the safety and performance of the battery can be improved simultaneously. |