SEPARATOR FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

The present disclosure relates to a separator for a lithium secondary battery, including: a porous polymer substrate; and a porous coating layer disposed on at least one surface of the porous polymer substrate, and including first inorganic particles surface-treated with a polyphenol-based compound, second inorganic particles surface-treated with an organic acid and a binder polymer, wherein the first inorganic particles have an average particle diameter of 100-700 nm, and the second inorganic particles have an average particle diameter of 30-80 nm, and a lithium secondary battery including the same. The separator for a lithium secondary battery uses two types of surface-treated inorganic particles having a different average particle diameter. Therefore, the inorganic particles have improved dispersibility, and the separator has high thermal safety and can prevent separation of the inorganic particles.