La_1.85Sr_1.15Cu_{2鈭?span style='font-style: italic'>x}Co_xO_6+未 intergrowth oxides as cathodes for intermediate temperature solid oxide fuel cells

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• 作者：Y.N. Kim ; A. Manthiram ; ^{rmanth@mail.utexas.edu}
• 关键词：Solid oxide fuel cells ; Oxygen reduction reaction ; Composite cathodes ; Crystal chemistry
• 刊名：Electrochimica Acta
• 出版年：2012
• 期刊代码：30_00134686
• 类别：ch
• 出版时间：30 May, 2012
• 卷：70
• 期：Complete
• 页码：375-381
• 文件大小：1428 K

摘要

The effect of the substitution of Co for Cu in the intergrowth oxide La_1.85Sr_1.15Cu_2鈭?em>xCo_xO_6+未 on the crystal chemistry, thermal and electrical properties, and catalytic activity for oxygen reduction reaction (ORR) has been investigated to determine its viability as a cathode material for intermediate temperature solid oxide fuel cells (SOFCs). The larger size and preference for higher oxygen-coordination number of the La³⁺/Sr²⁺ ions allow intercalation of excess oxygen between the two CuO₂ layers, and vacancies are introduced into the O(1) sites of the CuO₂ planes. The La_1.85Sr_1.15Cu_2鈭?em>xCo_xO_6+未 oxides show thermal expansion coefficients (TEC) of 鈭?5 脳 10^鈭? 掳C^鈭? that are compatible with that of the Gd_0.2Ce_0.8O_1.9 (GDC) electrolyte in SOFC. Fuel cell data collected with electrolyte-supported and anode-supported single cells reveal that the La_1.85Sr_1.15Cu_2鈭?em>xCo_xO_6+未 + GDC (50:50 vol.%) composite cathodes exhibit lower polarization resistance compared to the pure La_1.85Sr_1.15Cu_2鈭?em>xCo_xO_6+未 cathodes due to the extended triple phase boundary (TPB) where the ORR occurs. Among the various cathode compositions investigated in this study, the La_1.85Sr_1.15Cu_1.8Co_0.2O_6.26 + GDC composite was found to be optimal with the lowest polarization loss.