Organic-inorganic composite membrane for secondary battery, method for manufacturing the same, and lithium secondary battery including the same

A method for manufacturing an organic-inorganic composite membrane for a secondary battery, the method comprising:

• (S1) preparing a slurry composition for manufacturing an organic-inorganic composite membrane, the slurry composition containing a fluorine-based copolymer, lithium-lanthanum-zirconium-based oxide particles, a first solvent, and a second solvent;
• (S2) forming a porous matrix by applying and drying the slurry composition;
• and
• (S3) impregnating a multifunctional monomer composition into the porous matrix and performing curing to form a crosslinked network polymer electrolyte,
• wherein the fluorine-based copolymer contains 10 to 25 wt % of a hexafluoropropylene-derived repeating unit.