Abstract
BaZr0.8 - xPrxY0.2O3 - δ (BZPYx, 0.1 ≤ x ≤ 0.4) perovskite oxides were investigated for application as cathode materials for intermediate temperature solid oxide fuel cells based on proton conducting electrolytes (protonic-SOFCs). The BZPYx reactivity with CO2 and water vapor was evaluated by thermogravimetric and X-ray diffraction analyses, and good chemical stability was observed for each BZPYx composition. Conductivity measurements of BZPYx sintered pellets were performed as a function of temperature and pO2 in humidified atmospheres, corresponding to cathode operating condition in protonic-SOFCs. Different conductivity values and activation energies were measured depending on the Pr content, suggesting the presence of different charge carriers. For all the compositions, the partial electronic conductivity, calculated from conductivity measurements at different pO2, increased with increasing the temperature from 500 to 700 °C. Furthermore, the larger the Pr content, the larger the electronic conductivity. BaZr0.7Pr0.1Y 0.2O3 - δ and BaZr0.4Pr 0.4Y0.2O3 - δ showed mostly pure proton and electron conductivity, respectively, whereas the intermediate compositions showed mixed proton/electronic conductivity. Among the two mixed proton/electronic conductors, BaZr0.6Pr0.3Y 0.2O3 - δ presented the larger conductivity, which coupled with its good chemical stability, makes this perovskite oxide a candidate cathode materials for protonic-SOFCs.
Original language | English (US) |
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Pages (from-to) | 30-35 |
Number of pages | 6 |
Journal | Solid State Ionics |
Volume | 202 |
Issue number | 1 |
DOIs | |
State | Published - Nov 2 2011 |
Externally published | Yes |
Keywords
- Barium zirconate
- Mixed conductivity
- Praseodymium
- Proton conductor
- Solid oxide fuel cell
ASJC Scopus subject areas
- General Chemistry
- Condensed Matter Physics
- General Materials Science