Binder composition for secondary battery

A binder composition for a secondary battery electrode comprising a copolymer and a dispersion medium, wherein the copolymer comprises a structural unit (a) derived from a carboxylic acid group-containing monomer, a structural unit (b) derived from an amide group-containing monomer, a structural unit (c) derived from a nitrile group-containing monomer, a structural unit (d) derived from a hydroxyl group-containing monomer, and at least one anionic reactive emulsifier;

• wherein the proportion of structural unit (a) derived from a carboxylic acid group-containing monomer in the copolymer is from about 2% to about 13% by mole, the proportion of structural unit (b) derived from an amide group-containing monomer in the copolymer is from about 20% to about 37% by mole, the proportion of structural unit (c) derived from a nitrile group-containing monomer in the copolymer is from about 52% to less than 70% by mole, wherein the proportion of structural unit (d) derived from a hydroxyl group-containing monomer in the copolymer is from about 2% to about 10% by mole, based on the total number of moles of monomeric units in the copolymer in the binder composition;
• wherein the proportion of the anionic reactive emulsifier is from about 0.1% to about 5% by weight, based on the total weight of monomers added in the preparation of the binder composition;
• and wherein the binder composition is free of structural unit derived from a non-hydroxyl group-containing ethylenically unsaturated ester monomer.