Inorganic particle coating composition including binder, silane-based dispersant, fatty acid, and polymer polyol, method for preparing separator using the same, and separator and lithium battery employing the separator

A coating composition for a separator, the coating composition comprising:

• inorganic particles;
• a binder;
• a silane-based dispersant;
• and
• a polymeric additive,
• wherein:
• the silane-based dispersant consists of a silane-based compound comprising an alkyl main chain having one to seven carbons,
• the polymeric additive comprises a fatty acid compound and a polymer polyol,
• the silane-based compound comprises at least one selected from a vinyl alkyl alkoxysilane, an epoxy alkyl alkoxysilane, an amino alkyl alkoxysilane, a mercaptoalkyl alkoxysilane, a halogenated alkyl alkoxysilane, and an alkyl acyloxysilane,
• the fatty acid compound comprises a C15 to C30 unsaturated fatty acid compound, a C15 to C30 saturated fatty acid compound, or a combination thereof,
• the polymer polyol comprises one or more selected from a polycarbonate polyol, a polyester polyol, polyether polyol, a poly(meth)acryl polyol, and a polydiene polyol,
• wherein an acid value of the fatty acid compound is about 20 mg KOH/g to about 600 mg KOH/g, and
• wherein:
• an amount of the polymeric additive is about 1 to about 20 parts by weight, based on 100 parts by weight of the inorganic particles,
• a weight ratio of the fatty acid compound and the polymer polyol is about 1:0.2 to about 1:2, and
• the polymer polyol has a number average molecular weight of about 500 to about 5000, and has no alicyclic structure.