Umicore Ag & Co Kg

Joachim Köhler

Karl-Anton Starz

Sandra Wittpahl

Knut Fehl

Anita Krämer

Manfred Diehl

Ralf Zuber

Klaus Schaack

Volker Bänisch

Armin Bayer

Christian Eickes

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 present invention relates to the field of electrochemical cells and fuel cells, more specifically to polymer-electrolyte-membrane (PEM) fuel cells and describes a process for the manufacture of membrane-electrode-assemblies (MEAs) containing five layers. The five-layer MEA is assembled together by means of a lamination process involving an adhesive component. The anode gas diffusion layer, the catalyst-coated membrane and the cathode gas diffusion layer are combined together by a low temperature/low pressure lamination process. Handling of the MEAs and assembly of the products into PEMFC and DMFC stacks is simplified. Less damage and perforation of the catalyst-coated membrane occurs and thus the performance of the five-layer MEAs is significantly improved.

Process for the manufacture of membrane-electrode-assemblies using catalyst-coated membranes

The present invention relates to a method for the production of a membrane electrode assembly comprising a polymer electrolyte membrane with two opposing membrane surfaces and a cathode and an anode electrode each comprising a catalyst layer and a gas distribution layer. Each catalyst layer is interposed between a membrane surface and the corresponding gas distribution layer. The catalyst layer of the cathode and/or the catalyst layer of the anode comprise at least two sub-layers. According to the present invention at least one of the sub-layers of the cathode electrode and/or the anode electrode is applied directly to the surface of the membrane while the remaining sub-layers are applied to the corresponding gas distribution layers. Finally the assembly of the coated membrane and the coated gas distribution layers is produced.

Method for the production of membrane electrode assemblies for fuel cells

A process for producing a membrane electrode assembly for fuel cells containing a polymer electrolyte membrane having a first and a second surface parallel to each other. The first surface forms a firm composite with a first catalyst layer and a first water repellent gas distribution layer and said second surface form a firm composite with a second catalyst layer and a second water repellent gas distribution layer. The catalyst layers are prepared by using inks containing electrocatalysts, one or more solvents, proton-conducting ionomer and optionally water repelling agents and pore-forming agents. In the process the two catalyst layers are applied to or contacted with the respective surfaces of the polymer electrolyte membrane successively, wherein during the application or contacting process to one surface always the opposite surface of the membrane is supported.

Process for producing a membrane electrode assembly for fuel cells

The invention comprises a process for making a membrane electrode assembly comprising a polymer electrolyte membrane having two opposite faces, on each face of which is applied a catalyst layer and a gas distribution layer. The two gas distribution layers in the membrane electrode assembly are formed by hydrophobized carbon substrates which, using appropriate inks containing at least one catalyst, dissolved ionomer and solvent, are each coated with a catalyst layer and are then laid on opposite faces of the polymer electrolyte membrane with the catalyst layers still in the moist state. Afterwards, a firm bond between electrolyte membrane, catalyst layers and carbon substrates is produced by treating the membrane electrode assembly at elevated temperature under pressure.

Process for producing a membrane electrode assembly and the membrane electrode assembly produced thereby

The present invention relates to water-based catalyst inks and their use for manufacture of catalyst-coated substrates. According to the present invention, a catalyst layer is applied to the hydrophobic surface of a substrate by using a water-based catalyst ink comprising an electrocatalyst, an ionomer and water. The catalyst ink also comprises a highly volatile surfactant having a vapor pressure at ambient temperature in the range of 1 to 600 Pa. The use of this surfactant allows applying the water-based ink to the hydrophobic surface of a variety of substrates, such as gas diffusion layers, advanced ionomer membranes and polymer substrates. The required coating deposit can be applied in one coating pass and the resulting catalyst layer exhibits improved performance due to the absence of residual surfactant in the catalyst layer.

Growing community of inventors

Gründau/Haingründau, Germany

Joachim Köhler