Sofc

Acta mater. 48 (2000) 4709–4714 www.elsevier.com/locate/actamat

GADOLINIA-DOPED CERIA AND YTTRIA STABILIZED ZIRCONIA INTERFACES: REGARDING THEIR APPLICATION FOR SOFC TECHNOLOGY
A. TSOGA1*, A. GUPTA1, A. NAOUMIDIS1 and P. NIKOLOPOULOS2
Institut fur Werkstoffe und Verfahren der Energietechnik (IWV1), Forschungszentrum Julich, D-52425 ¨ ¨ Julich, Germany and 2Chemical Engineering Department, University of Patras, GR 265 00 Patras, Greece ¨
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Abstract—For solid oxide fuel cells (SOFCs) operating at intermediate temperatures the adjacency of the state-of-the-art yttria-stabilized zirconia (YSZ) electrolyte with ceria-based materials to both anodic and cathodic sides is regarded as crucial for the effectiveness of the cell. Solid-state reaction, however, and interdiffusion phenomena between YSZ and ceria-based materials can cause degradation of the electrolyte. When a gadolinia-doped-ceria (GDC) layer is used to protect YSZ against interaction with Co-containing cathodes, an unfavorable solid state reaction at the YSZ–GDC interface can be efficiently suppressed when a thin ( 1 µm thick) interlayer with nominal composition of Ce0.43Zr0.43Gd0.10Y0.04O1.93 is incorporated at the interface. When ceria is to be employed at the electrolyte–anode interface to reduce polarization losses, use of a ceria–40% vol Ni cermet is recommended, since suppression of the reactivity between YSZ and ceria can also be achieved in the presence of Ni. © 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. Keywords: Solid oxide fuel cells; Interface; Diffusion; Microstructure

1. INTRODUCTION

Reduction of the operation temperature of solid oxide fuel cells (SOFCs) from 900–1000°C to 700–800°C is of great importance because it means both a prolonged stack lifetime and a cost reduction, since the use of low-cost metallic components as separator materials is then possible. However, for the operation of SOFCs at intermediate temperature to be technically

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