Origin of cathodic degradation and new phase formation at the La0.9Sr0.1MnO3/YSZ interface

被引:80
作者
Lee, HY
Oh, SM
机构
关键词
lanthanum zirconate; cathode degradation in SOFC; ohmic losses; AC impedance; current interruption;
D O I
10.1016/S0167-2738(96)00408-0
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
New phase formation at the La0.9Sr0.1MnO3/YSZ interface and its effects on the cathodic performances were studied at 900 degrees C in air. The resistance caused by the interfacial product layer kept increasing with time to reach up to 40% of the total resistance after 500 h. The interfacial product was identified as La2Zr2O7 by XRD measurement. The electrical conductivity of La2Zr2O7 (2.4 X 10(-5) S cm(-1) at 1000 degrees C), measured by AC impedance and current interruption methods, was 4 to 7 orders of magnitude smaller than those of La0.9Sr0.1MnO3 electrode or YSZ electrolyte. Either the electronic conductivity or the electrochemical O-2 reduction activity of La2Zr2O7 was negligible. Combining these results, a conclusion was made that the cathodic degradation comes mainly from the growth of interfacial product layer and its contribution to the cell resistance increment is ohmic in nature.
引用
收藏
页码:133 / 140
页数:8
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