Solid electrolytic capacitor with conductive polymer as solid

Abstract

The solid electrolytic capacitor disclosed has a conducting polymer as a solid electrolyte and an antioxidant contained substantially only in a layer disposed in the neighborhood of a surface of the conducting polymer. The antioxidant serves to block the progress of oxidation of organic materials. A capacitor element with conducting polymer not containing the antioxidant is first prepared and this capacitor element is then dipped in a solution containing the antioxidant. Thus, the antioxidant at high concentration is caused to be introduced into the conducting polymer so as to be contained substantially only in a layer disposed in the neighborhood of the surface of the conducting polymer. Since the antioxidant can be introduced by merely dipping the capacitor element in the antioxidant solution, the method can be applied widely to capacitors irrespective of the process of conducting polymer formation. The antioxidant concentration inside the conducting polymer is substantially zero so that the conductivity thereof is not affected.