【作者】 段枣树；

【导师】 程谟杰；

【作者基本信息】 中国科学院研究生院（大连化学物理研究所） ， 化学工程， 2005， 硕士

【摘要】 钙钛矿氧化物Ba_xSr_1-xCo_0.8Fe_0.2O_3-δ由于其高催化活性、高的透氧率和良好的稳定性是固体氧化物燃料电池的一种新型阴极材料。本文采用EDTA-柠檬酸法合成了Ba_xSr_1-xCo_0.8Fe_0.2O_3-δ （BSCF;x=0.2⁰.7）系列材料,并对其进行了电导率的测定,研究探讨了BSCF在阳极支撑的LSGM电解质电池、YSZ电解质和GDC电解质隔膜电池上的应用和材料间相容性问题。在整个温度范围内,BSCF的电导率随着Ba含量的增加在下降。在低温阶段,电导率随着温度的升高而增大,电子传导遵循小极化子导电机理。BSCF阴极在LSGM电解质型电池上表现出很好的性能,电池在以空气为氧化剂时800°C的最高功率密度可达1.6 W/cm²。可能是由于阴极与电解质间离子的相互扩散,导致电解质和电极的组成改变,使得电池的开路电位比理论开路电位低、几个不同组分阴极的过电位和电池性能没有差别。BSCF材料与YSZ电解质化学相容性较差,在900°C便开始反应,生成了SrZrO₃、BaZrO₃等;而BSCF与GDC的化学相容性比较好。在阳极支撑的YSZ电解质与BSCF阴极间烧制了一层GDC薄膜,以隔绝BSCF与YSZ的反应。结果发现在添加了GDC隔层后,电池性能有了极大的提高,极化电阻急剧降低。GDC焙烧温度为1250°C时,电极-电解质的界面反应最小,电池性能最佳。该电池在800°C,以空气为氧化剂,氢气为燃料的最大功率密度为1.56 W/cm²。更多还原

【Abstract】 The new mixed ionic and electronic conducting materials, Ba_xSr_1-xCo_0.8Fe_0.2O_3-δ （BSCF）, were investigated as new cathode materials for IT-SOFCs. The cells with BSCF cathodes on the LSGM electrolyte, YSZ electrolyte and GDC electrolyte were fabricated and examined.The electrical conductivity of these samples decreases with Ba content in the temperature range from 200°C to 800°C. In the low temperature range, the conductivity increases with temperature and Ln（σT） varies linearly with reciprocal temperature, which indicates that electrical conduction takes place primarily by the small polaron hopping mechanism.The cells with BSCF cathode on LSGM electrolyte exhibit high performances, and the maximum power densities are all about 1.6 W/cm² using air as oxidant at 800°C, which is similar to that of a state-of-art cell with an LSM-YSZ cathode using oxygen as oxidant. The same overpotentials of different Ba-doping BSCF cathodes suggests that the diffusions of the ions between the BSCF cathodes and the LSGM electrolyte are serious.The interfacial reactions between BSCF and YSZ occur at 900°C, whereas BSCF shows a good chemical compatibility with the GDC electrolyte. A thin GDC buffering layer, as thin as about 1μm, was introduced between the BSCF cathode and the YSZ electrolyte film. The results depict a great improvement in cell performance and a significant decrease in polarization resistance after adding更多还原