A wet electrolytic capacitor that contains an anodically oxidized porous anode body, a cathode containing a metal substrate coated with a conductive coating, and a working electrolyte that wets the dielectric on the anode. The conductive coating is formed through anodic electrochemical polymerization (“electro-polymerization”) of a microemulsion on the surface of the metal substrate. The microemulsion is a thermodynamically stable, isotropic liquid mixture that contains a precursor monomer, sulfonic acid, nonionic surfactant, and solvent.