BINDER FOR ELECTRODE OF LITHIUM ION SECONDARY BATTERY

摘要

A binder for electrode of lithium ion secondary battery, comprised of a copolymer composed of 15 to 80 mass% of units of ethylenically unsaturated monomer (A) whose homopolymerization yields a polymer soluble in N-methylpyrrolidone (NMP) and 20 to 85 mass% of units of ethylenically unsaturated monomer (B) whose homopolymerization yields a polymer insoluble in NMP, which copolymer exhibits a swelling degree of 4 or below in an electrolyte obtained by dissolving LiPF6 in a concentration of 1 mol/liter in a solvent of 1:2 (volume ratio at 20°C) mixture of ethylene carbonate (EC) and diethyl carbonate (DEC). This binder for electrode of lithium ion secondary battery enables obtaining an electrode having a flexible electrode layer excelling in binding properties with industrial advantage.