Pr1－xSrxAlO3－δ的合成及其作为固体氧化物燃料电池阴极的性能研究

采用固相反应法合成了一系列样品Pr_1－xSr_xAlO_3－δ (x＝0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5). XRD结果表明, Sr在A位上的固溶度约为20%; 利用交流阻抗法测量了样品的电导率, 结果表明, 电导率随着Sr掺入量的增加而增大, Pr_0.8Sr_0.2AlO_3－δ的电导率最大, 在850 ℃达到0.02 S/cm; 离子迁移数的测试结果说明, Pr_1－xSr_xAlO_3－δ为离子电子混合导体; 考察了它们作为固体氧化物燃料电池(SOFCs)阴极的性能, 极化曲线和阻抗的测试结果表明, 阴极性能随着Sr掺入量的增加而提高; 阴极稳定性测试结果表明, 在测量时间范围内, 阴极过电位随时间缓慢下降.

Synthesis and Properties of Pr1-xSrxAlO3-δ as Cathode of Solid Oxide Fuel Cells

Compounds Pr_1－xSr_xAlO_3－δ (x＝0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) were successfully synthesized by solid state reaction method and XRD results showed that the solubility of Sr^2＋ on A site was about 20%. The electrical conductivity measured by alternating current (AC) impedance was increased with increasing Sr content. The sample with x＝0.2 exhibited the best performance on the conductivity. At 850 ℃, the value was 0.02 S/cm. Results of ionic transfer number measurement indicated that the Pr_1－xSr_xAlO_3－δ samples were the mixed ionic-electronic conductors. Both cathode polarization and AC impedance results showed that Sr^2＋doping greatly improved the cathode performance. A short-term stability test of the cathode was done and the result showed that there was a slight decrease of the cathode over-potential during the test.