Lithium secondary battery separator including adhesive layer

A coating composition, comprising:

• a solvent, inorganic particles, a dispersant, and a binder,
• wherein the binder comprises a binder B and a binder A,
• both the binder B and the binder A comprise a vinylidene fluoride (VDF)-derived unit and a hexafluoropropylene (HFP)-derived unit,
• binder B comprises 8 to 50 wt % of the HFP-derived unit, and binder A comprises 5 wt % or more of the HFP-derived unit under a condition that a proportion of the HFP-derived unit in the binder A is 80% or less of a proportion of the HFP-derived unit in the binder B,
• the binder B has a total number average molecular weight of 200,000 to 2,000,000 Da, and the binder A has a total number average molecular weight corresponding to 70% or less of that of the binder B, and
• a weight ratio of the binder A:the binder B in the coating composition is 0.1 to 10:1,
• said coating composition being suitable for use in coating at least one surface of a porous substrate having a plurality of pores.