Verfahren zur Herstellung einer Silberelektrode

摘要

A porous silver electrode for the electrochemical reduction of gaseous oxygen in a fuel cell or other primary battery is produced by forming a blank from an inorganic compound containing silver and oxygen, subjecting the blank to a temperature of at least 300 DEG C. for no more than 3 minutes to form a conductive silver layer on at least part of the surface of the blank, and electrochemically reducing the remainder of the inorganic compound to silver. Typically, dry washed silver carbonate, precipitated from a solution containin sodium bicarbonate and silver nitrate in decinormal proportions with or without the addition of 0.2 to 5 times its weight of ammonium carbonate, is pressed into tablets and heated, e.g. at 140 DEG C., to decompose the silver carbonate to silver oxide and to eliminate the ammonium carbonate if present, and the resulting porous silver oxide structure is then briefly irradiated with infra-red to produce a metallic silver surface, e.g. on one face. Alternatively the blank may be heated with infra-red immediately after forming to form the silver layer. The cooled electrode blank is then placed in a holder with an electrical contact engaging the silver surface and immersed as cathode in 1N KOH and electrolyzed at 1A/sq. dm. until the body of silver oxide was reduced to silver, optionally with oxygen being simultaneously blown through the blank.