Chemical printing of raw aluminum anode foil to induce uniform patterning etching

Abstract

A method of producing a highly etched electrode for a capacitor from a foil is disclosed. The method comprises first applying a composition to the foil to form a plurality of deposits on the foil surface. The method then includes heating the deposits to form micron-sized features and etching the foil. Preferably, the micron-sized features facilitate etching of the foil surface at the location of the micron-sized features. After etching, the foil is optionally further processed in a combination of optional steps such as widening, forming and finishing steps. The controlled application and heating of deposits on the foil surface allows for positional control of tunnel initiation during etching. Thus, the present invention relates to a method of controlling the etching of a foil, such that tunnel initiation density and the location of tunnel initiation is controlled. By controlling the position of tunnel initiation, foils are etched more uniformly and have optimum tunnel distributions, thus allows for the production of highly etched foils that maintain high strength and have high capacitance. The present invention further includes an electrolytic capacitor comprising etched aluminum anode foils, which have been prepared using the methods of the present invention.