Why don't the electrodes of a fuel cell deteriorate the way the electrodes of a battery do?

Answer 1

The electrodes of a storage battery, particularly the lead - lead dioxide batteries commonly used in starting vehicles, may deteriorate because the discharge reaction requires one or both of the solid electrodes used to dissolve partially in the electrolyte, and the recharging reaction requires depositing new solid on both electrodes from the electrolyte. In order to maximize the possible output of electric current from a battery during the discharge or working phase, the electrodes have special surface characteristics that maximize their effective surface area. Both the charging and discharging phases of use of a battery of this type often decrease the effective surface area of the solid electrodes, and the recharging in particular may deposit solid on one or both of the electrodes in a shape that causes it to short to the other electrode.

This does not occur in fuel cells, because the solid electrodes of a fuel cell do not dissolve during use. Instead, the electrodes serve (1) as catalysts to promote the oxidation and reduction reactions of fuels supplied to the electrodes as liquids or gases dissolved in the electrolyte and (2) to accept or furnish the electrons needed for the reactions to occur at separate locations. Furthermore fuel cells never need recharging, because the reactants consumed are replenished from outside the fuel cell itself and not regenerated within the cell, as for a storage battery.