In a solid polymer fuel cell series, various circumstances can result in a
fuel cell being driven into voltage reversal by other cells in the series
stack. For instance, cell voltage reversal can occur if that cell receives
an inadequate supply of fuel (for example, fuel starvation). In order to
pass current during fuel starvation, reactions other than fuel oxidation
may take place at the fuel cell anode, including water electrolysis and
oxidation of anode components. The latter may result in significant
degradation of the anode. Such fuel cells can be made more tolerant to
cell reversal by promoting water electrolysis over anode component
oxidation at the anode. This can be accomplished by enhancing the presence
of water in the anode catalyst layer through modifications to the anode
structure or anode composition near or in the catalyst layer. For
instance, water electrolysis during voltage reversal is promoted through
the use of different or additional ionomer, polytetrafluoroethylene, or
graphite in the anode catalyst layer, or through the use of certain
sublayers between the anode catalyst layer and the anode substrate.