ELECTROLYTIC CAPACITOR AND ELECTROLYTE FOR DRIVING IT

PROBLEM TO BE SOLVED: To obtain an electrolyte contributing to high breakdown voltage, high heat resistance and long lifetime by dissolving borate represented by a specific formula and/or a salt thereof as solute. SOLUTION: Borate represented by formulas 1, 2, 3 (R1, R2, R3 may be any one of-CH2O, -C2H4O, -C3H6O, -C4H8O and the terminal -CHa may be -H, l, m, n, k are arbitrary natural number) and/or a salt thereof is dissolved, as a solute, into organic solvent. Inorganic acid, e.g. boric acid or ammonium borate, and/or a salt thereof and an organic acid and/or a salt thereof are also contained and the borate represented by formulas 1, 2, 3 and/or a salt thereof is dissolved, as a solute. Boric acid or ammonium borate is added by 10 wt.% or less in order to prevent open valve of an electrolytic capacitor even under an environment of 100 deg.C or above.