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Electrolyte-supported cells: Progress through electrolyte development

 
: Kellner, M.; Betz, T.; Kuznecov, M.; Trofimenko, N.

Mogensen, M. ; World Fuel Cell Council e.V.; European Fuel Cell Forum:
Sixth European Solid Oxide Fuel Cell Forum 2004. Proceedings. Vol.3 : 28 June - 2 July 2004, Lucerne, Switzerland; in conjunction with the Fuel Cell World
Oberrohrdorf/Switzerland: European Fuel Cell Forum, 2004
ISBN: 3-905592-15-0
pp.1075-1082
European Solid Oxide Fuel Cell Forum <6, 2004, Luzern>
English
Conference Paper
Fraunhofer IKTS ()
scandiumoxidstabilisiertes Zirkoniumoxid

Abstract
The electrolyte supported cells satisfy the requirements for the application in the solid oxide fuel cell such as mechanical stability, long term stability during operation at T less 1000 deg C, thermal cycling and very low degradation during repeated anode reduction/oxidation cycles. Nevertheless to make them more competitive to the anode supported cells an enhancement of the power density at T=800 deg C - 850 deg C should be achieved. The most important parameter which influences the cell resistance is the ionic conductivity of the electrolyte. The enhancement of the ionic conductivity can be achieved using Sc-doped zirconia. The substrates from 5ScSZ-, 10ScSZ-powders and from mixtures of 3YSZ and 10ScSZ powders are manufactured and compared with 8YSZ and 3YSZ standard products. Ionic conductivity, microstructure and polarization resistance of the electrodes are characterized. It is shown that the SScSZ and 3YSZ/10ScSZ-electrolytes have both enhanced ionic conductivity and excellent mechanical properties. The sintered substrates from the developed materials have a rest porosity which can be reduced by optimizing the sintering conditions. To minimize the polarization resistance of the cathode the surface roughness of the 3YSZ substrate is modified. The cells based on these substrates are characterized under operating conditions. The influence of the surface modification on the polarization resistance of the cathode is discussed.

: http://publica.fraunhofer.de/documents/N-35163.html