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Cathode performance: Influence of MOD-intermediate layer and electrolyte surface enlargement

 
: Herbstritt, Dirk; Weber, A.; Müller, A.; Guntow, Uwe; Müller, Gerd; Ivers-Tiffée, Ellen

McEvoy, A.J. ; World Fuel Cell Council e.V.:
Fourth European Solid Oxide Fuel Cell Forum 2000. Proceedings. Vol.2 : 10 - 14 July 2000, Lucerne/Switzerland
Oberrohrdorf/Switzerland: European Fuel Cell Forum, 2000
pp.697-706
European Solid Oxide Fuel Cell Forum (SOFC) <4, 2000, Lucerne>
English
Conference Paper
Fraunhofer ISC ()
Batterie; Elektrolyte; Kathodenmaterial

Abstract
An electrolyte supported planar single cell with screen printed electrodes displays a considerable polarisation resistance at both electrode/electrolyte interfaces. The development of electrode/electrolyte interfaces with low overpotential and improved long term stability is important for low and high temperature applications of SOFCs. For a conventional strontium doped lanthanummanganite cathode (LSM: La0.8Sr0.2MnO3) on an 8YSZ electrolyte substrate (8YSZ: 8 mol% Y2O3 doped ZrO2) the cathodic reaction is generally assumed to be restricted to the three phase boundary (tpb) LSM/8YSZ/air.
In this work, the electrochemical active area was increased by a thin (80-100nm) microporous interface layer using the MOD technique (MOD: Metal organic deposition).
A three dimensional cathode/electrolyte interface was realized by first screen printing a porous monolayer of individual YSZ particles (~17μm) onto the electrolyte substrate (8YSZ). Second a thin intermediate layer of substoichiometric LSM (ULSM: La0.75Sr0.2MnO3) or LSC (La0.5Sr0.5MnO3) was applied by MOD technique. Finally, a screen printed ULSM layer (approx. 30μm in thickness) was applied as a current collector and gas distribution layer. Single cells with this modified cathode/electrolyte interface showed a considerable increase in power output, long term stability and thermomechanical stability.

: http://publica.fraunhofer.de/documents/N-441682.html