A wet electrolytic capacitor including a porous anode body containing a dielectric layer, a cathode containing a metal substrate on which is disposed a conductive polymer coating, and an electrolyte is provided. The conductive polymer coating is in the form of a dispersion of particles having an average diameter of from about 1 to about 500 nanometers, in some embodiments from about 5 to about 400 nanometers, and in some embodiments, from about 10 to about 300 nanometers. The relatively small size of the particles used in the coating increases the surface area that is available for adhering to the metal substrate, which in turn improves mechanical robustness and electrical performance (e.g., reduced equivalent series resistance and leakage current). Another benefit of employing such a dispersion for the conductive polymer coating is that it may be able to better cover crevices of the metal substrate and improve electrical contact.