| abstract |
Disclosed is an aluminum electrolytic capacitor having low impedance properties and a long service life. Also disclosed is an electrolytic solution which enables the production of the capacitor.nThe electrolytic solution comprises a water-containing solvent, a phosphorus oxoacid ion-generating compound which can generate a phosphorus oxoacid ion in an aqueous solution, and a chelating agent which can coordinate with an aluminum to form a water-soluble aluminum chelate complex. The electrolytic solution additionally comprises a compound selected from the group consisting of azelaic acid and an azelaic acid salt and a compound selected from the group consisting of formic acid, a formic acid salt, adipic acid, an adipic acid salt, glutaric acid and a glutaric acid salt. The content of azelaic acid and/or the azelaic acid salt is at least 0.03 mole per kg of the solvent. When the electrolytic solution is used in an aluminum electrolytic capacitor which utilizes an anode having an aluminum oxide film containing phosphorus in an amount of 30 to 150 mg in terms of phosphoric acid content per unit CV product, the service life of the capacitor can be remarkably prolonged. |