玻璃密封胶与固体氧化物燃料电池元件相容性分析

Analysis on Compatibility between Glass-Ceramic Sealants and the Components of Solid Oxide Fuel Cells

采用高温熔融法制备了用于固体氧化物燃料电池的一系列SrCO_3-Al_2O_3-SiO_2(SAS)系统玻璃陶瓷材料。通过调节封接材料中的SrCO_3的含量可以控制玻璃陶瓷的热膨胀性能。结果表明,SrCO_3含量为19.85 mol%的玻璃陶瓷密封胶在25～850℃之间的平均热膨胀系数α为12.52×10^(-6) K^(-1),这与La_(0.8)Sr_(0.2)MnO_3(LSM)阴极,YSZ电解质和Fe-Cr合金连接体等电池元件之间有良好的热膨胀匹配性。在800～900℃范围内,SAS体系密封胶与上述的电池元件有很好的相容性,该密封胶与LSM和YSZ电解质等电池材料之间有很好界面接合性,并且在电池的工作温度下有很好的热稳定性,在850℃烧结120h以后其失重率基本不再发生变化,在烧结140 h后的失重率仅为0.378%。经放电实验检测,该密封材料的封接性能良好,开路电压为1.03V,放电的最大功率密度为183 mW/cm^2。结果表明,SrCO_3-Al_2O_3-SiO_2系统玻璃陶瓷密封胶可以作为固体氧化物燃料的封接材料。

The SrCO3-Al2O3-SiO2（SAS） glass-ceramic materials have been investigated as SOFC（solid oxide fuel cells） sealants. Sealants with different thermal expansion coefficient a values were prepared by adjusting the SrCO3 content in the raw materials. In the study, the sealant material which has the α 12.52 × 10^-6K^-1 from 25 ℃ to 850 ℃ achieved the best sealing effect. The first reason for this lies in that the a of the sealant matches well with other components of the cells from 25 ℃ to 900 ℃, including the La0.8Sr0.2MnO3 （LSM） cathode, YSZ electrolyte and the Fe-Cr alloy interconnect. Furthermore, this kind of sealant also maintains a high stability at the operating temperature of the SOFC and its mass loss was only 0.378% after being heat-treated at 800 ℃ for 140 h. According to the test, the cell sealed by this kind of sealant possesses an open voltage of 1.03 V and a power density of 183 mW/cm^2. Thus, this material can work well as a sort of glass-ceramic sealants for SOFCs.