高性能Sm0.5Sr0.5CoO3阴极的制备与表征

用固相合成法合成了Sm0.5Sr0.5CoO3 (SSC)中温固体氧化物燃料电池阴极材料.以La0.9Sr0.1Ga0.8Mg0.2O3为电解质,利用多种技术考察了不同温度(1173～1373 K)焙烧的SSC阴极,以及1173 K 焙烧、掺杂La0.8Sr0.2Ga0.8Mg0.15Co0.05O3(LSGMC5)或La0.8Sr0.2Ga0.8Mg0.09Co0.11O3 (LSGMC11)高氧离子电导材料的复合SSC阴极.SEM的结果显示,随着电极焙烧温度的增加,电极的颗粒度增大,孔隙度减小；LSGMC5、LSGMC11的掺杂对电极微观结构影响不大.交流阻抗和极化实验的结果表明,SSC电极的活性随电极焙烧温度的增加而减小,电极的最佳焙烧温度在1173 K左右；掺杂了LSGMC5或LSGMC11的复合SSC电极的活性以及稳定性显著高于SSC电极.

Preparation and Characterization of High Performance Sm0.5Sr0.5CoO3 Cathodes

Sm0.5Sr0.5CoO3(SSC) powders were prepared using solid-state reaction. The XRD pattern of SSC corresponded to a desired perovskite structure. SSC electrodes sintered at various temperatures (1 173-1 373 K) and SSC-La0.8Sr0.2Ga0.8Mg0.15Co0.05O3 (SSC-LSGMC5), SSC-La0.8Sr0.2Ga0.8Mg0.09Co0.11O3 (SSC-LSGMC11) composite cathodes sintered at 1 173 K were studied using SEM, impedance spectroscopy, and DC(direct current) polarization. The electrodes studied were prepared on La0.9Sr0.1Ga0.8Mg0.2O3 electrolytes using screen-printing. The particle size of SSC electrodes increased with sintering temperatures, and the porosity decreased accordingly. The addition of LSGMC5 and LSGMC11 into SSC had no obvious effect on the microstructure of SSC electrodes. The results of AC (alternative current) impedance spectroscopy and DC polarization showed that the activity of SSC electrodes increased with decreasing sintering temperature, and the optimum sintering temperature for SSC electrodes was about 1 173 K. The addition of LSGMC5 or LSGMC11 into SSC improved both the activity and stability of SSC electrodes significantly.