Electrochemical fuel cell stacks comprising a plurality of membrane
electrode assemblies stacked in an alternating manner, such that the
polarity of adjacent membrane electrode assemblies are opposite, are
disclosed. The fuel cell stacks comprise a plurality of membrane
electrode assemblies, each membrane electrode assembly comprising an
anode fluid distribution layer, a cathode fluid distribution layer, a
polymer electrolyte membrane interposed between the anode and cathode
fluid distribution layers, an anode electrocatalyst layer interposed
between the polymer electrolyte membrane and the anode fluid distribution
layer, and a cathode electrocatalyst interposed between the polymer
electrolyte membrane and the cathode fluid distribution layer, wherein
the plurality of membrane electrode assemblies are stacked in an
alternating manner such that the polarity of adjacent membrane electrode
assemblies are opposite, and wherein the plurality of membrane electrode
assemblies are externally jumpered. Methods for shutting down the fuel
cell stacks are also disclosed.