Electrolytic capacitor

Abstract

An electrolytic capacitor includes a porous anode body, a dielectric layer formed on a surface of the anode body, and a conductive polymer and a salt compound that are filled inside pores of the anode body. L is a shortest distance from a center of the anode body to a first principal surface of the anode body, the first principal surface being closest to the center, and a region in which a minimum value of respective distances to principal surfaces of the anode body is L/3 or less, and a region in which the minimum value is 2L/3 or more, are defined as a surface layer part and a central part, respectively, inside the anode body. A ratio B/A of an ion strength B derived from the salt compound to a sum A of all ion strengths measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS) in a cross section that passes through the center and that is perpendicular to the first principal surface is defined as an ion strength ratio. A ratio R2/R1 of an ion strength ratio R2 in the central part of the anode body to an ion strength ratio R1 in the surface layer part of the anode body is 0.15 or more.