التفاصيل البيبلوغرافية
| العنوان: |
Effects of chromium poisoning on the long-term oxygen exchange kinetics of the solid oxide fuel cell cathode materials La0.6Sr0.4CoO3 and Nd2NiO4 |
| المؤلفون: |
Yang, Min1, Bucher, Edith1, Sitte, Werner sitte@unileoben.ac.at |
| المصدر: |
Journal of Power Sources. Sep2011, Vol. 196 Issue 17, p7313-7317. 5p. |
| مصطلحات موضوعية: |
*SOLID oxide fuel cells, *CATHODES, *CHROMITE, *NITRIDES, *CHEMICAL kinetics, *CHROMIUM, *ELECTRIC conductivity, *RELAXATION phenomena |
| مستخلص: |
Abstract: The influence of chromium poisoning on the long-term stability of the oxygen exchange kinetics of the promising IT-SOFC cathode materials La0.6Sr0.4CoO3−δ (LSC) and Nd2NiO4+δ (NDN) is investigated in-situ by dc-conductivity relaxation experiments. The as-prepared LSC and NDN samples show high chemical oxygen surface exchange coefficients k chem. After the deposition of a 10nm thick Cr-layer onto the surface, k chem of LSC decreases to 50% of the initial value. Additional chromium deposition of 20nm on LSC leads to a further decrease of k chem to 27% of the initial value. In contrast, the effect of a 10nm thick Cr-layer on k chem of NDN is negligible. Even with additional 20nm of chromium and a total testing time of 1750h, the nickelate retains a k chem of 60% of the initial value. X-ray photoelectron spectroscopy (XPS) of the degraded. LSC shows a significantly altered surface cation composition with Sr-enrichment down to 30nm depth while XPS analysis of the degraded NDN reveals a thin surface zone of approximately 30nm containing nickel and chromium. In contrast to LSC, the changes in the surface composition of NDN due to Cr-poisoning ultimately had only a minor influence on the surface exchange properties. [Copyright &y& Elsevier] |
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