Sputtered Fuel Cell Electrodes

Abstract

Hydrogen and oxygen fuel cell electrodes were postcatalyzed by sputtering Pt onto carbon and nickel gas diffusion substrates. The i‐V performance depends strongly on the characteristics of the porous substrate. With a properly prepared substrate, reduction current densities out to 500 mA/cm2 could be sustained at potentials above . However, the data indicate that at the higher current densities (>100 mA/cm2), the reaction is catalyzed partly by the high surface area carbon. The diffusion limited current density on the hydrogen electrodes was ∼10 mA/cm2. However, the Pt appears to assist in the reduction reaction out to several hundred mA/cm2. The reasons for this extreme difference have not yet been resolved. In any case, for postcatalyzation by sputtering to be successful as a process for fabricating fuel cell electrodes, improved wetproofing techniques are required to increase the electrolyte repellency of the porous substrate over that now available with various Teflons.