Abstract: Disclosed is a composition comprising an ethylene copolymer and a halogenated polymer, wherein the ethylene copolymer comprises or is produced from repeat units derived from ethylene and a comonomer selected from the group consisting of an ?,?-unsaturated monocarboxylic acid or its derivative, an ?,?-unsaturated dicarboxylic acid or its derivative, an epoxide-containing monomer, a vinyl ester, or combinations of two or more thereof; and the composition can further comprise a curing agent to crosslink the ethylene copolymer. The composition is useful as a binder for a lithium ion battery.