Umicore Ag & Co Kg

Degussa Aktiengesellschaft

Degussa - Huls Ag

Dmc2 Degussa Metals Catalysts Cerdec Ag

Degussa-huls Aktiengellschaft

Ralf Zuber

Knut Fehl

Sandra Wittpahl

Klaus Schaack

Karl-Anton Starz

Peter Seipel

Holger Dziallas

Udo Stenke

Armin Bayer

Pia Braun

Matthias Binder

Markus Maier

Alexander Kabza

Ralf Karch

Manfred Diehl

Marco Lopez

Thomas Lehmann

Markus Vogt

Lutz Rohland

Hartmut Wendt

Joachim Köhler

Joachim Koehler

Anita Krämer

Willi Peter

Andreas Fischer

Günther Vulpius

Gerhard Heinz

Volker Baenisch

Sven Bornbaum

Volker B&auml;nisch

Bernd Dillmann

Heike K&uuml;hnhold

Wolfgang G&ouml;ttenauer

Elisabeth Kasper

Markus Maler

Joachim Kohler

Anita Kramer

Markus Gelz

The present invention relates to the field of electrochemical cells and fuel cells, and more specifically to polymer-electrolyte-membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC). It is directed to catalyst-coated ionomer membranes ('CCMs') and membrane-electrode-assemblies ('MEAs') that contain one or more protective film layers for protection, sealing and better handling purposes. The one or more protective film layers are attached to the surface of said catalyst-coated membranes in such a way that they overlap with a region of the passive non-coated ionomer area, and with a region of the active area that is coated with a catalyst layer. Furthermore, the present invention discloses a process for manufacture of CCMs and MEAs that contain protective film layers. The materials may be used as components for the manufacture of low temperature fuel cell stacks.

Process for manufacturing a catalyst-coated ionomer membrane with protective film layer

The invention relates to a membrane-electrode assembly (MEA) for electrochemical devices, in particular for membrane fuel cells. The membrane-electrode assembly has a semi-coextensive design and comprises an ion-conducting membrane, two catalyst layers and gas diffusion layers of differing sizes on the front side and rear side. The first gas diffusion layer has smaller planar dimensions than the ion-conducting membrane, while the second gas diffusion layer has essentially the same planar dimensions as the ion-conducting membrane. As a result, the ion-conducting membrane has a surface which is not supported by a gas diffusion layer on the front side. The membrane-electrode assembly has, owing to the particular construction, a stable structure which can be handled readily and displays advantages in the sealing of the reactive gases from one another and also in terms of the electrical properties. In particular, the hydrogen penetration current is significantly reduced. New processes for producing the MEA of the invention are described, in particular the method of heat pulse welding. The membrane-electrode assembly is used in PEM fuel cells, direct methanol fuel cells, electrolysers and other electrochemical devices.

Membrane electrode assembly for use in electrochemical devices

The invention relates to the field of electrochemical cells and fuel cells, more specifically to polymer-electrolyte-membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC). A multi-layer membrane-electrode-assembly (ML-MEA) comprising two electrically conductive bipolar plates and a membrane-electrode-assembly (MEA) bonded together by means of an electrically insulating adhesive material is disclosed. The adhesive material, preferably a polyurethane-based system, is in direct contact with the protective film layers attached to front side and the back side of the MEA, thus contamination of the ionomer membrane and/or the electrode layers with adhesive components is avoided. Multi-layer MEAs with improved long term stability and life time are obtained. The products are used for the manufacture of low temperature PEMFC and DMFC stacks.

Multi-layer membrane-electrode-assembly (ML-MEA) and method for its manufacture

The invention relates to membrane-electrode assemblies for the electrolysis of water (electrolysis MEAs), which contain an ion-conducting membrane having a front and rear side; a first catalyst layer on the front side; a first gas diffusion layer on the front side; a second catalyst layer on the rear side, and a second gas diffusion layer on the rear side. The first gas diffusion layer has smaller planar dimensions than the ion-conducting membrane, whereas the second gas diffusion layer has essentially the same planar dimensions as the ion-conducting membrane ('semi-coextensive design'). The MEAs also comprise an unsupported free membrane surface that yields improved adhesion properties of the sealing material. The invention also relates to a method for producing the MEA products. Pressure-resistant, gastight and cost-effective membrane-electrode assemblies are obtained, that are used in PEM water electrolyzers, regenerative fuel cells or in other electrochemical devices.

Membrane electrode unit for the electrolysis of water

Catalyst-coated ionomer membrane with protective film layer and membrane-electrode-assembly made thereof

An ink is disclosed for producing membrane electrode assemblies for fuel cells which contains a catalyst material, an ionomer, water and an organic solvent. The ink is characterized in that the organic solvent is at least one compound from the group of linear dialcohols with a flash point higher than 100&#xb0; C. and is present in the ink in a concentration between 1 and 50 wt. %, with respect to the weight of water.

Ink for producing membrane electrode assemblies for fuel cells

The invention relates to a process for recycling fuel cell components containing fluorine-containing and precious metal-containing constituents: in this process, the fluorine-containing constituents are separated off from the precious metal-containing constituents by treatment with a medium present in the supercritical state. Preference is given to using water as supercritical medium. After the fluorine-containing constituents have been separated off, the precious metal-containing residues can be recovered in a recycling process without harmful fluorine or hydrogen fluoride emissions. The fluorine-containing constituents can likewise be recovered. The process is used in the recovery of precious metals and/or fluorine-containing constituents from membrane fuel cells, electrolysis cells, batteries, sensors and other electrochemical devices.

Process for recycling fuel cell components containing precious metals

A membrane electrode assembly for polymer electrolyte fuel cells consisting of a polymer electrolyte membrane, both faces of which are in contact with porous reaction layers and gas distributor layers. The reaction layers contain noble metal catalysts supported on carbon and a proton-conducting polymer, a so-called ionomer. At least one of the two reaction layers also contains a noble metal black.

Membrane electrode unit for polymer electrolyte fuel cells and a process for the production thereof

A gas diffusion structure for polymer electrolyte fuel cells having a sheet-like carbon substrate made hydrophobic and having two main opposing surfaces and a contact layer on one of these surfaces. The contact layer is formed of an intimate mixture of at least one hydrophobic polymer, which can be polyethylene, polypropylene or polytetrafluoroethylene, and finely divided carbon particles, wherein the weight percentage of the carbon particles relative to the total weight of the contact layer amounts to 40 to 90 wt. %. The gas diffusion structure is a carbon substrate made hydrophobic by at least one hydrophobic polymer and the hydrophobic polymers are restricted to two layers extending from both opposing surfaces into the carbon substrate down to a depth of from 5 to 40 &mgr;m and the hydrophobic polymers fill of from 20 to 60% of the pore volume within those layers.

Gas diffusion structures and gas diffusion electrodes for polymer electrolyte fuel cells

A PEM fuel cell stack including one or more fuel cells ( ) arranged on top of one another, each of which contains a membrane electrode assembly ( ) between two electrically conductive bipolar plates ( ), the surfaces of which are equipped with flow channels ( ) open on one side for the supply of reactive gases, whereby the membrane electrode assemblies each comprise a polymer electrolyte membrane ( ), both sides of which are in contact with a reaction layer ( ), whereby the surface area of the reaction layers is smaller than that of the polymer electrolyte membrane and a compressible, coarse-pore gas distribution layer ( ) made from carbon fiber fabric is inserted between each reaction layer and the adjacent bipolar plates congruent to the reaction lawyers along with seals ( ) in the area outside the surface covered by the gas distribution layers, whereby the gas distribution layers in the no-load condition display a thickness D and the seals a thickness D . The PEM fuel cell stack is featured by the gas distribution layers in the PEM fuel cell stack being compressed to 25 to 60% of the original thickness.

PEM fuel cell stack

A process is disclosed for applying electrode layers to a polymer electrolyte membrane strip in a desired pattern, wherein the front and back of the membrane are continuously printed with the electrode layers in the desired pattern using an ink containing an electrocatalyst, and the printed electrode layers are dried at elevated temperature immediately after the printing operation, the printing taking place while maintaining accurate positioning of the patterns of the electrode layers on the front and back in relation to one another.

Process for applying electrode layers to a polymer electrolyte membrane strip for fuel cells

A membrane-electrode unit for polymer-electrolyte fuel cells. The membrane-electrode unit consists of a polymer electrolyte membrane and porous reaction layers applied to both sides comprising a catalyst and a proton-conducting polymer, a so-called ionomer. The membrane-electrode unit is characterized in that one part A,of the catalyst of the reaction layers is saturated with the ionomer and is embedded in the ionomer whereas one part A,of the catalyst is kept free from the ionomer, where the parts A,and A,are in a weight ratio of 1:1 to 20:1.

Membrane-electrode unit for polymer electrolyte fuel cells and processes for their preparation

A catalyst layer on a substrate material which contains a proton-conducting polymer (ionomer), electrically conductive carbon particles and fine particles of at least one precious metal. The catalyst layer is obtainable by coating the substrate material with an ink which contains a dispersion of the carbon particles and at least one organic precious metal complex compound in a solution of the ionomer, and drying the coating below a temperature at which the ionomer or the substrate material is thermally damaged, the precious metals in the complex compounds being present with an oxidation number of 0 and the complex compounds being thermally decomposed during drying to form the fine precious metal particles.

Catalyst layer for polymer electrolyte fuel cells

A stable paste for fired-on layers which produces few pyrolysis products contains 0.3 to 3 wt. % of polyethylenimine as binder. The binder inhibits sedimentation of the contents of the paste.

Pastes for fired-on layers

Growing community of inventors

Grossostheim, Germany

Ralf Zuber