US Patent 9208954 Electrolytic capacitor

An electrolytic capacitor includes a capacitor element, an electrolyte solution with which the capacitor element is impregnated, and an outer package enclosing the capacitor element and the electrolyte solution. The capacitor element includes an anode foil having a dielectric layer on a surface thereof, a cathode foil, a separator disposed between the anode foil and the cathode foil, and a solid electrolyte layer in contact with the dielectric layer of the anode foil and the cathode foil. The electrolyte solution contains a low-volatile solvent that is at least one of polyalkylene glycol and a derivative of polyalkylene glycol.