Elcomax Membranes Gmbh

Volkswagen Ag

Ulrich Maehr

Dieter Melzner

Suzana Kiel

Annette Reiche

Stefan Haufe

A membrane-electrode assembly and polymer electrolyte fuel cells and methods of production thereof, in which a polymer membrane, containing at least one basic polymer membrane, is sandwiched between two flat gas diffusion electrodes each of which is loaded with a dopant, whereby after reaching a mass transport equilibrium for the exchange of the dopant between the gas diffusion electrodes and the polymer membrane, the polymer membrane has a conductivity of at least 0.1 S/m at a temperature of no less than 25&#xb0; C.

Membrane-electrode assembly, polymer membranes for a membrane-electrode assembly, polymer electrolyte fuel cells, and methods for the production thereof

A membrane for fuel cells, which is characterized by a homogeneous absorption and good retention of doping agents, and which guarantees a high mechanical stability at high temperatures when doped. Such membranes consist of at least one polymer, whose nitrogen atoms are chemically bonded to a central atom of a derivative of a polybasic inorganic oxo acid. The membranes are produced from polymer solutions that are devoid of water and oxo acid derivatives, by heating the solution that has been introduced into a membrane mold until a self-supporting membrane has been formed and then by thermally regulating the latter. Inventive fuel cells having a membrane electrode assembly (MEA) that comprises a membrane of the invention and phosphoric acid as the doping agent have, for example, an impedance of 0.5-1 &#x3a9;cmat a measuring frequency of 1000 Hz and at an operating temperature of 160&#xb0; C. and a gas flow for hydrogen of 170 mL/min and for air of 570 mL/min. They can be used as high-temperature polyelectrolyte membrane fuel cells for a working temperature of up to at least 250&#xb0; C.

Membranes for fuel cells, method for producing said membranes and production of fuel cells using membranes of this type

A membrane electrode assembly (MEA) for a fuel cell, which has a planar polymer membrane. This membrane, in a tangentially inner area, is coated on both sides with electrode structure, and, in a tangentially outer area projecting at least on one side beyond the electrode structure coating, is connected to a sealing member. A marginal zone of the polymer membrane is embedded in the elastomer sealing member. The sealing member extends tangentially inward to a transition area that lies tangentially between the outer area and the inner area, where it overlaps the electrode structures on outer faces of the electrode structures, on both of the sides of the polymer membrane.

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Berlin, Germany

Ulrich Maehr