التفاصيل البيبلوغرافية
| العنوان: |
Impact of SO2 on the Oxygen Exchange Kinetics of the Promising SOFC/SOEC Air Electrode Material La0.8Ca0.2FeO3-δ. |
| المؤلفون: |
Berger, Christian, Bucher, Edith, Gspan, Christian, Menzel, Alexander, Sittea, Werner |
| المصدر: |
Journal of The Electrochemical Society; 2017, Vol. 164 Issue 10, pF3008-3018, 11p |
| مصطلحات موضوعية: |
SULFUR dioxide, OXYGEN, ELECTRODES |
| مستخلص: |
The mass and charge transport properties of La0.8Ca0.2FeO3-δ (LCF82) were determined at 600-800±C and pO2 = 0.1 bar. The electronic conductivity is in the range of 112 S cm-1 at 700±C. The chemical surface exchange coefficient (kchem) and the chemical diffusion coefficient of oxygen (Dchem) were measured. LCF82 shows exceptionally fast oxygen exchange kinetics in pure O2-Ar at 700±C. Long-term measurements at 700±C in pure O2-Ar showed an excellent stability of the kinetic parameters during 1000 h. However, when 2 ppm of sulfur dioxide were added, kchem decreased by a factor of 40 within the first 24 h. After further 1000 h, the total decrease in kchem amounted to two orders of magnitude. Post-test analyses of LCF82 were performed by SEM-EDXS, XPS, and STEM. Ca-enrichment and La-/Fe-depletion of the LCF82 surface occurred during the first 1000 h without SO2. At the surface of the sample exposed to 2 ppm SO2 for additional 1000 h, CaSO4 crystals with diameters of 1-2 µm and an underlying layer of Fe2O3 (thickness approx. 300-450 nm) were found. Remarkably, LCF82 shows faster oxygen exchange kinetics than La0.6Sr0.4CoO3-δ even in the degraded state. Therefore, LCF82 is suggested as a promising material for SOFC and SOEC air electrodes. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
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