Process for improving leakage and dissipation factor of solid electrolytic capacitors employing conductive polymer cathodes

The adhesion of a conductive polymer film to an oxidized porous pellet anode is improved by the incorporation of a silane coupling agent in the polymer impregnating solution. The incorporation of the silane coupling agent also decreases leakage current and dissipation factor. Suitable silanes are those of the general formula (R1-R3)-Si-(OR2)3. Each of R2 and R3 is a C1-C6 alkyl group such as methyl, ethyl, or propyl. R1 can be chosen from a wide variety of organic functional groups such as epoxy, glycidoxy, amino, and pyrrole. The most preferred silane is 3-glycidoxypropyltrimethoxysilane.