NOVELTY - Manufacture of electrode involves forming electrode mixture layer on surface of electrical power collector by an electrode mixture composition containing crosslinking agent and polyimide precursor aqueous composition obtained by dissolving polyamide acid including isocyanate-group-containing derivative (I) with imidazole, having alkyl group in an aqueous solvent, after which the solvent is removed and polyamide acid is subjected to imidization reaction by heating. The crosslinking agent has carbodiimide group or oxazoline group.    USE - Manufacture of electrode used for lithium-ion secondary battery (claimed) used as power supply of mobile information terminal and hybrid vehicle.    ADVANTAGE - The method enables efficient and environmentally-friendly manufacture of electrode having excellent adhesiveness and toughness and reduced swelling degree in battery environment, in short period of time.    DETAILED DESCRIPTION - Manufacture of electrode involves forming electrode mixture layer on surface of electrical power collector by an electrode mixture composition containing crosslinking agent and polyimide precursor aqueous composition obtained by dissolving polyamide acid including 1.6 times mol or more isocyanate-group-containing derivative of formula (I) with imidazole, having 2 or more alkyl group as substituent with respect to the tetracarboxylic-acid component of polyamic acid, in an aqueous solvent, after which the solvent is removed and polyamide acid is subjected to imidization reaction by heating. The crosslinking agent has carbodiimide group or oxazoline group.    A=tetravalent group chosen from group of formula (ii)-(iv);    B'=bivalent group chosen from group of formula (v)-(x) and 4-10C bivalent saturated hydrocarbyl;and    X,Y'=direct bond, O, S, methylene, carbonyl, sulfoxy, sulfonyl, 1,1'-ethylidene, 1,2-ethylidene, 2,2'-isopropylidene, 2,2'-hexafluoroisopropylidene, cyclohexylidene, phenylene, 1,3-phenylene dimethylene, 1,4-phenylene dimethylene, 1,3-phenylene diethylidene, 1,4-phenylene diethylidene, 1,3-phenylene propylidene, 1,4-phenylene propylidene, 1,3-phenylene-dioxy, 1,4-phenylene-dioxy, biphenylene dioxy, methylene diphenoxy, ethylidene diphenoxy, propylidene diphenoxy, hexafluoro propylidene diphenoxy, oxydiphenoxy, thiodiphenoxy or sulfone diphenoxy.