Single step reactive sintering and chemical compatibility between La₉Sr₁Si₆O_26.5 and selected cathode materials

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• 作者：José ; M. Porras-Vá ; zquez^a ; ^b ; Luc&#237 ; a dos Santos-Gó ; mez^a ; Isabel Santacruz^a ; Miguel A.G. Aranda^a ; David Marrero-Ló ; pez^c ; Enrique R. Losilla^a ; ^{r_losilla@uma.es}
• 关键词：Apatite-type electrolyte ; SOFC ; Chemical compatibility ; Area-specific resistance
• 刊名：Ceramics International
• 出版年：2012
• 期刊代码：13_02728842
• 类别：ms
• 出版时间：May, 2012
• 卷：38
• 期：4
• 页码：3327-3335
• 文件大小：1007 K

摘要

Apatite-type silicates are considered as promising electrolytes for solid oxide fuel cells (SOFC). However more studies on the chemical compatibility of these materials with common SOFC electrodes are required. Here, we report the synthesis of single phase La₉Sr₁Si₆O_26.5 composition by reactive sintering at 1650 掳C for 10 h. Fully dense pellets showed very high oxide-anion conductivity, 25 mS cm^鈭? at 700 掳C. Furthermore, the chemical compatibility of La₉Sr₁Si₆O_26.5 with some selected cathode materials has also been investigated. The lowest reaction temperatures were determined to be 1100 掳C, 1000 掳C and 900 掳C for La_0.8Sr_0.2MnO_3鈭?em>未, La₂Ni_0.8Cu_0.2O₄ and La_0.6Sr_0.4Co_0.8Fe_0.2O₃, respectively. The segregation of minor amounts of SiO₂ seems to be a key limiting factor that must be overcome. Finally, these cathode materials were deposited over dense oxy-apatite pellets and the area specific resistances in symmetrical cells were determined. These values, at 700 掳C, were 14.4 and 2.6 惟 cm² for La_0.8Sr_0.2MnO_3鈭?em>未 and La_0.6Sr_0.4Co_0.8Fe_0.2O_3鈭?em>未, respectively. Furthermore, the area specific resistances are notably improved 0.6 惟 cm² when a 50 wt.%composite of La_0.6Sr_0.4Co_0.8Fe_0.2O_3鈭?em>未 and Ce_0.8Gd_0.2O_1.9 is used.