Chapter 56. Reduction and Re-Oxidation of Anodes for Solid Oxide Fuel Cells (Sofc)

  1. Edgar Lara-Curzio and
  2. Michael J. Readey
  1. Jürgen Malzbender1 and
  2. Forschungszentrum Jülich Gmbh2

Published Online: 26 MAR 2008

DOI: 10.1002/9780470291184.ch56

28th International Conference on Advanced Ceramics and Composites A: Ceramic Engineering and Science Proceedings, Volume 25, Issue 3

28th International Conference on Advanced Ceramics and Composites A: Ceramic Engineering and Science Proceedings, Volume 25, Issue 3

How to Cite

Malzbender, J. and Gmbh, F. J. (2004) Reduction and Re-Oxidation of Anodes for Solid Oxide Fuel Cells (Sofc), in 28th International Conference on Advanced Ceramics and Composites A: Ceramic Engineering and Science Proceedings, Volume 25, Issue 3 (eds E. Lara-Curzio and M. J. Readey), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470291184.ch56

Author Information

  1. 1

    Egbert Wessel and Rolf W. Steinbrech, Lorenz Singheiser

  2. 2

    Institute for Materials and Processes in Energy Systems 52425 Jülich, Germany

Publication History

  1. Published Online: 26 MAR 2008
  2. Published Print: 1 JAN 2004

ISBN Information

Print ISBN: 9780470051498

Online ISBN: 9780470291184

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Keywords:

  • SEM;
  • SOFC;
  • ECN;
  • FZJ;
  • ACC

Summary

The influence of reduction and re-oxidation on microstructure and residual stress has been studied for anode supported planar SOFCs. the transition in oxidation state shows a non-reversible behaviour. Shrinkage caused by the reduction of NiO to Ni is over-compensated in the re-oxidation step. Microstructural SEM observations reveal that after re-oxidation the NiO has a higher porosity and requires a larger volume than in the initial, oxidised state. the residual stress development has been analysed via monitoring of the curvature changes of unconstrained half-cells. Re-oxidation is a dynamic process that starts at the free surface of the anode and proceeds towards the interface with the electrolyte. Accordingly the residual stresses in the anode and electrolyte change. Ultimately, the tensile residual stress in the electrolyte exceeds tensile strength, resulting in cracks which lead to deterioration of the entire cell function.