| abstract |
Provided is a binder composition for a lithium ion secondary battery, comprising a cross-linking agent (A), a particulate binder (B), and water and having an aqueous phase and a solid phase, wherein the cross-linking agent (A) comprises a functional group that reacts with carboxylic acid; the particulate binder (B) contains an unsaturated ethylene carboxylic acid group monomer unit; and the ratio of the surface acid level of the particulate binder (B) to the total mass of the solid portion of the binder composition, the ratio of the acid level in the aqueous phase to the total mass of the solid portion of the binder composition, and the ratio of the surface acid level to the acid level in the aqueous phase are within prescribed ranges. |