Abstract: A counterelectrode and a method for providing the counterelectrode wherein an inherently high effective capacitance surface is formed on tantalum. The oxide forming ability of the tantalum surface is destroyed by removing existing oxide from the surface, depositing on the surface a layer of a platinum family metal, and alloying the deposited metal with the tantalum thereby forming an alloy layer. A second layer of metal, also selected from the platinum family, may then be deposited over the alloy layer. Alternately the platinum family metal may be sputtered or clad onto the surface of the tantalum with or without an alloying step. The second deposition produces a spongy layer and is accomplished by conventional electrolytic techniques.

Abstract: A counterelectrode and a method for providing the counterelectrode wherein an inherently high effective capacitance surface is formed on tantalum. The oxide forming ability of the tantalum surface is destroyed by removing existing oxide from the surface, depositing on the surface a non-continuous layer of a platinum family metal, and alloying the deposited metal with the tantalum thereby forming alloy layer. A second layer of metal, also selected from the platinum family, may then be deposited over the alloy layer. Alternately the platinum family metal may be sputtered onto the surface of the tantalum with or without an the alloying step. The second deposition produces a spongy layer and is accomplished by conventional electrolytic techniques.