PrBaCo<sub>2</sub>O<sub>6−δ</sub>-Ce<sub>0.8</sub>Sm<sub>0.2</sub>O<sub>1.9</sub> Composite Cathodes for Intermediate-Temperature Solid Oxide Fuel Cells: Stability and Cation Interdiffusion
oleh: Dmitry Tsvetkov, Nadezhda Tsvetkova, Ivan Ivanov, Dmitry Malyshkin, Vladimir Sereda, Andrey Zuev
| Format: | Article |
|---|---|
| Diterbitkan: | MDPI AG 2019-01-01 |
Deskripsi
The single-phase oxide PrBaCo<sub>2</sub>O<sub>6−δ</sub> and composites (100 − <i>y</i>)PrBaCo<sub>2</sub>O<sub>6−δ</sub>-<i>y</i>Ce<sub>0.8</sub>Sm<sub>0.2</sub>O<sub>1.9</sub> (<i>y</i> = 10⁻30 wt.%) were investigated as cathode materials for intermediate-temperature solid oxide fuel cells. The chemical compatibility, cation interdiffusion, thermal expansion and dc conductivity were studied. As a result, strong interdiffusion of Pr and Sm was found between PrBaCo<sub>2</sub>O<sub>6−δ</sub> and Ce<sub>0.8</sub>Sm<sub>0.2</sub>O<sub>1.9</sub>. This leads to only insignificantly decreasing thermal expansion coefficient of composite with increasing fraction of Ce<sub>0.8</sub>Sm<sub>0.2</sub>O<sub>1.9</sub> and, thus, mixing PrBaCo<sub>2</sub>O<sub>6−δ</sub> with Ce<sub>0.8</sub>Sm<sub>0.2</sub>O<sub>1.9</sub> does not improve thermal expansion behavior of the cathode material. Moreover, formation of poorly-conducting BaCeO<sub>3</sub>, caused by chemical interaction between the double perovskite and doped ceria, was shown to lead to pronounced drop in the electrical conductivity of the composite cathode material with increasing Ce<sub>0.8</sub>Sm<sub>0.2</sub>O<sub>1.9</sub> content.