Journal article
Accelerated creep in solid oxide fuel cell anode supports during reduction
Department of Energy Conversion and Storage, Technical University of Denmark1
Mixed Conductors, Department of Energy Conversion and Storage, Technical University of Denmark2
Imaging and Structural Analysis, Department of Energy Conversion and Storage, Technical University of Denmark3
Fundamental Electrochemistry, Department of Energy Conversion and Storage, Technical University of Denmark4
European Spallation Source ERIC5
To evaluate the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. The creep of reduced Ni-YSZ anode support at operating conditions has been studied previously.
In this work a newly discovered creep phenomenon taking place during the reduction is reported. This relaxes stresses at a much higher rate (∼ x104) than creep during operation. The phenomenon was studied both in three-point bending and uniaxial tension. Differences between the two measurements could be explained by newly observed stress promoted reduction.
Finally, samples exposed to a small tensile stress (∼ 0.004 MPa) were observed to expand during reduction, which is in contradiction to previous literature. These observations suggest that release of internal residual stresses between the NiO and the YSZ phases occurs during reduction. The accelerated creep should practically eliminate any residual stress in the anode support in an SOFC stack, as has previously been indirectly observed.
This phenomenon has to be taken into account both in the production of stacks and in the simulation of the stress field in a stack based on anode supported SOFCs. (C) 2016 Elsevier B.V. All rights reserved.
Language: | English |
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Year: | 2016 |
Pages: | 78-89 |
ISSN: | 18732755 and 03787753 |
Types: | Journal article |
DOI: | 10.1016/j.jpowsour.2016.04.097 |
ORCIDs: | Frandsen, Henrik Lund , Makowska, Malgorzata Grazyna , Chatzichristodoulou, Christodoulos , Kuhn, Luise Theil and Hendriksen, Peter Vang |