Polymer-electrolyte membrane fuel cell

A polymer-electrolyte membrane fuel cell comprising a laminate of such membrane (6), an electrode (5) containing a catalyst, a porous, electrically conductive gas diffusion layer (3, 4) and a current collector plate (1) having a gas distribution channel structure (2), the cell having a gradient of the gas permeability, which gradient is present at least in a partial area, in the laminate in the direction perpendicularly to the membrane, with a higher gas permeability closer to the membrane (6) an a lower gas permeability closer to the current collector plate (1), wherein in operation at the membrane by a hydrogen-oxygen reaction water and heat are produced, characterized in that the gas permeability gradient exists in the gas diffusion layer (3, 4) which is adjacent to the electrode (5) containing the catalyst, and that at least in said partial area of the gas diffusion layer (3, 4) the gas permeability closer to the current collector plate (1) is lower to such a degree than in the vicinity of the membrane (6) that a gas composition occurs which over the surface of the membrane (6) is approximately constant, and the water which at the operating temperature is generated in vaporform creates such a water vapor diffusion stream through the gas diffusion layer that such a humidity content of the membrane which is optimal for the conductivity is materially being maintained.