GB1107525A - Improvements in cell electrodes - Google Patents

Abstract

Grains of active carbon are coated with silver by suspending them in an ammoniacal solution of silver nitrate, heating and stirring the suspension and adding formaldehyde thereto. After decanting the coated grains are washed with HCl and distilled water and dried. The grains obtained are agglomerated with a temporary binder, shaped, sintered under pressure and for a time adequate to secure a good adhesion by diffusion. The body so-formed is used as a cell electrode. The grains may be spread on a metal e.g. sintered Ni support prior to sintering. The sintered electrode may be made impermeable by impregnation in a solution of petroleum wax in kerosene.ALSO:A fuel cell electrode is produced by coating grains of active carbon with a metal used as a catalyst in the reaction occurring within the cell, agglomerating the coated carbon grains to the desired electrode shape and sintering the agglomerate under pressure and for a time appropriate to secure a good adhesion by diffusion. The metal may be coated on to the carbon powder by chemical or electro-chemical action. The coated grains may be mixed with a temporary binding agent to agglomerate them and they may be spread on a metal or sintered metal, e.g. Ni, support prior to sintering. The sintered electrode may be rendered impermeable by immersion in a suitable liquid e.g. 10% by weight solution of petroleum wax in kerosene. The metal coating exemplified is silver and the method of coating is to suspend active carbon in a solution of ammonical silver nitrate which is stirred and heated to 50 DEG C. and add formaldehyde thereto. After decoating, the coated grains are washed in HCl, and then distilled water and dried, and subsequently agglomerated, shaped and sintered.