Siemens Aktiengesellschaft

Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.

Winfried Schaffrath

Peter Otschik

Robert Fleck

Armin Datz

Manfred Waidhas

Barbara Schricker

Nikolai Trofimenko

Michael Kuznecov

A method for producing a solid electrolyte layer, of a fully stabilized zirconium oxide layer on a substrate includes adding a sintering additive to a ZrO2-starting material, a liquid phase is formed during a sintering process and liquid phase sintering is possible at a reduced temperature in comparison with the required sintering temperature without the sintering additive. The reduced sintering temperature substantially prevents the formation of a foreign phase layer between the substrate and the gas-tight layer applied thereon, being of fully stabilized ZrO2. The method is particularly suitable for producing a solid electrolyte layer on a cathode of a high temperature fuel cell and in a sensor.

Process for producing a solid electrolyte layer on a substrate, in a fuel cell, and in a sensor

A screen-printing paste as a starting material for fabricating a gas diffusion electrode through screen-printing includes at least one polymer, at least one metallic catalyst, and a high-boiling solvent. The polymer is a binder including poly(butyl acrylate)-polymethacrylate copolymer, a poly(vinyl alcohol), and a poly(ethylene oxide). The polymer can be two polymers, a first being used for hydrophobicization and present in an amount of between 0 to 10% by weight based on a content of the metallic-catalyst, and a second being a binder. A screen-printing method of fabricating the electrode for a fuel cell includes forming a screen-printing layer having a thickness between 3 and 40 &mgr;m by applying the screen-printing paste to a base. The solvent and the polymer serve as a screen-printing medium. The screen-printing layer is baked to allow only residues of the solvent and the polymer to remain, which do not interfere with using the electrode in a fuel cell. The method uses a polybutylacrylate-polymethacrylate copolymer as a binder in the screen-printing paste.

Screen-printing paste and screen-printing method of fabricating a gas diffusion electrode

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Dresden, Germany

Winfried Schaffrath