A capacitor comprising an electrode body of an electrode material, wherein a dielectric at least partly covers the surface of this electrode material and forms an anode body, wherein the anode body is at least partly coated with a solid electrolyte which comprises polythiophenes and polyanions, wherein the polythiophene is poly(3,4-ethylenedioxythiophene), the polyanion is a polystyrenesulphonic acid and wherein the weight ratio of poly(3,4-ethylenedioxythiophene):polystyrene-sulphonic acid in the solid electrolyte is at least 0.67 and is less than 1.5.