Studies of Fe-Co based perovskite cathodes with different A-site cations

被引：55

作者：

Kammer, K. ^{[1
]}

机构：

[1] Riso Natl Lab, Dept Mat Res, DK-4000 Roskilde, Denmark

来源：

SOLID STATE IONICS | 2006年 / 177卷 / 11-12期

关键词：

perovskite; cathode; SOFC; Fe-Co; CGO10;

D O I：

10.1016/j.ssi.2006.03.007

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：

Iron-cobalt based perovskite cathodes with different A-site cations ((Ln(0.6)Sr(0.4))(0.99)Fe0.8Co0.2O3-delta, where Ln is La, Pr, Sm or Gd) have been synthesised, characterised by a powder XRD, dilatometry, 4-point DC conductivity measurements, and electrochemical impedance spectroscopy (EIS) on cone shaped electrodes. In addition to this scanning electron microscopy (SEM) was used to characterise the bars. XRD revealed that only the La-containing perovskite was hexagonal. The Pr and Sm perovskites were orthorhombic. The gadolinium-based perovskite was a two phase system consisting of an orthorhombic and a cubic perovskite phase. The thermal expansion coefficient (TEC) increased systematically with a decrease in the size of the A-site cation until the gadoliniurn-containing perovskite where the TEC decreases abruptly. The total electric conductivity was the highest for the La-based perovskite and the lowest for the Gd-based perovskite as determined by 4-point DC conductivity measurements on bars. A clear correlation between the size of the A-site cation and the electrochemical performance was revealed, as the area specific resistance (ASR) was the lowest for the compounds with the smallest A-site cation. This might be explained on the background of the creation of a two-phase structure with a unique microstructure when the size of the A-site cation is lowered, or that one of the phases has a high electro-catalytic activity towards the electrochemical reduction of oxygen. (c) 2006 Elsevier B.V. All rights reserved.

引用

页码：1047 / 1051

页数：5

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