A binder composition used for making an electrode for a lithium-ion
secondary battery, which comprises polymer particles dispersed in an
organic medium having a boiling point of 80-350.degree. C. at normal
pressure. The polymer (1) comprises structural units derived from a
monoethylenically unsaturated carboxylic acid ester monomer, and at least
one kind of structural units selected from (b) structural units derived
from a monoethylenically unsaturated carboxylic acid monomer and (c)
structural units derived from a conjugated diene monomer; (2) has a ratio
of (a)/[(b)+(c)] of 99/1-60/40 by weight; (3) has a total content of (a),
(b) plus (c) of at least 80 wt. % based on the total structural units; and
(4) is substantially free from structural units of a monoethylenically
aromatic hydrocarbon monomer. A lithium-ion secondary battery having an
electrode made with the binder exhibits a large service capacity and
enhanced charge-discharge characteristics at a high temperature.
