Lightweight fuel cell membrane electrode assembly with integral reactant flow passages

An electrochemical fuel cell is provided for converting a fuel reactant stream and an oxidant reactant stream to a reaction product and electrical energy. The fuel cell comprises a membrane electrode assembly comprising a first electrode layer and a second electrode layer, wherein said first electrode layer (261) comprises a fuel stream inlet (264), a fuel stream outlet (266), and means for flowing said fuel stream between said fuel stream inlet and said fuel stream outlet and said second electrode layer comprises an oxidant stream inlet, an oxidant stream outlet, and means for flowing said oxidant stream between said oxidant stream inlet and said oxidant stream outlet, wherein said flow means comprises interstitial spaces within at least one of said electrode layers, and wherein at least one of said electrode layers further comprises dam members (265) for diverting the flow of the reactant stream within said electrode layers.