Membrane electrode assemblies and fuel cells having increased durability

Membrane-electrode-unit (I) comprises two electrochemical active electrodes (1,3) (A) (that are separated by a polymer-electrolyte-membrane (5) (B)) and sealing material (7, 9) (C) on the front and the back of (B), which exhibits one or more fissures (11) and (C) on the front and the back of (B) are in contact with each other. Membrane-electrode-unit (I) comprises two electrochemical active electrodes (1,3) (A) (that are separated by a polymer-electrolyte-membrane (5) (B) and where the surfaces of (B) is in contact with (A) and the first electrode (1) and the second electrode (3) completely or partially covers the front and the back, respectively, of (B)) and sealing material (7,9) (C) on the front and the back of (B), which exhibits one or more groove (11) and (C) on the front and the back of (B) are in contact with each other. Independent claims are also included for the preparation of (I); and a fuel cell comprising (I).