The following thesis demonstrates two isotope tracing experiments that measure oxygen transport through electrochemically polarized solid oxides. Cathode-symmetric ‘button’ cells with yttria stabilized zirconia(YSZ) electrolytes and either strontium doped lanthanum manganate(LSM) or composite LSM/YSZ cathodes were studied. The first experiment measured the residence time distributions(RTD) of 34O2. The measured RTDs were compared at different temperatures(700-800°C) and applied potentials(-2 to -8V). Comparisons with simulated RTDs revealed that oxygen transport was laterally heterogeneous. Delamination of the counter electrode is likely the source of the heterogeneity. The second experiment measured a wave of 18O by exposing an interior cross section and applying ToF-SIMS analysis. A depth profile was produced that spans the cathode and electrolyte interface. The depth profile was compared with a variety of limiting oxygen activation scenarios predicted by a simple 1-D model. Comparisons demonstrated that oxygen activation is likely not restricted to the cathode and electrolyte interface.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/27372 |
| Date | 31 May 2011 |
| Creators | Wood, Thomas |
| Contributors | Mims, Charles A. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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