| abstract |
In the present invention, as a single-layer freestanding separator for secondary batteries with improved elongation and tensile strength, heat resistance, and heat shrinkage, microfibers, binder polymers, and inorganic particles are included, and the microfibers are composed of island components and sea components. Is derived from the island component of the island-in-the-sea yarn, the microfiber includes an elastic polymer, the binder polymer includes a polymer derived from the sea component, and the inorganic particles are bound to each other by the binder polymer in contact with each other, As a result, an interstitial volume is formed between the inorganic particles in contact with each other, the interstitial volume between the inorganic particles becomes an empty space to form pores, and the microfiber is entangled between the inorganic particles. Inorganic particles are fixed to each other, and a single-layer free-standing separator for a secondary battery that does not include a porous polymer substrate is provided. |