PURPOSE: To obtain an electrolyte, which has little change in its specific resistance value and can satisfy a thermal stability, by a method wherein using a γ-butyrolactone as its main solvent carboxylate and/or a carboxylic acid anhydride are/is added to the tertiary amine salt of the carboxylic acid.
CONSTITUTION: Using a γ-butyrolactone as its main solvent a carboxylate is added to the tertiary amine salt of the carboxylic acid. Moreover, a carboxylic anhydride and water are added. Here, the carboxylate and/or the carboxylic acid anhydride are/is respectively added to the tertiary amine salt of the carboxylic acid at 1 to 25wt.%. The water is added to the tertiary amine salt of the carboxylic acid at 1 to 15wt.%. Thereby, an electrolyte, which has less change in its specific resistance than that in the specific resistance of a conventional electrolyte and has a good thermal stability, can be obtained.
ITAMI SHOJI
URAMOTO MASAHIDE
FUKUDA MITSURU
