Aluminum electrolytic capacitor

An electrolyte capable of anodizing aluminum consists essentially of a solution of an amino acid having a pH of 5.5 to 8.5. The amino acid is preferably a 2-amino acid, more preferably a dicarboxylic acid, and specifically aspartic or glutamic acid. The electrolyte may be used to anodize aluminum foil to form a barrier layer oxide or as a fill electrolyte in aluminum electrolytic capacitors.