Abstract: A fuel cell electrolyte with an electrochemically inactive matrix, an electrochemically active electrolyte, and a substantially gas impervious metallic foil in the central region of the thickness of the electrolyte extending around its periphery over at least a portion of the fuel cell peripheral seal area and into the electrolyte active area reducing gas crossover between the anode and cathode chambers. The gas impervious metallic foil may extend beyond the periphery of the electrolyte into the fuel cell peripheral seal area and have a resilient gasket on each side forming the fuel cell peripheral seal with seal structures extending from separator plates, thereby eliminating conventional electrolyte wet seals. The seal structures according to this invention are also suitable for sealing internal manifolds in fuel cell stacks.