Lowering the operating temperature of solid oxide fuel cells (SOFCs) is highly desirable to reduce the cost and increase the lifetime, which relies upon the development of a cathode component with high oxygen reduction reaction (ORR) activity at a lower temperature. Herein, we report the characterization of high‐performance BaSc_xCo_1‐xO_3‐δ (x=0, 0.125, 0.25, and 0.375) perovskite SOFC cathodes. Unlike BaCoO_3‐δ, which adopts 2H‐hexagonal perovskite structure, the replacement of 25 mol % of Co with Sc stabilizes the cubic structure, which also leads to the significant reduction in area specific resistances and their activation energies between 650 and 500 °C (for BaSc_0.25Co_0.75O_3‐δ) relative to the non‐doped BaCoO_3‐δ. In this temperature range, BaSc_0.25Co_0.75O_3‐δ displayed a remarkably high ORR activity compared to Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3‐δ (BSCF), the current cathode benchmark. We attribute such superior ORR performance to the higher oxygen non‐stoichiometries of BaSc_0.25Co_0.75O_3‐δ relative to BSCF, which also translates to the higher oxygen bulk diffusion and surface exchange coefficients for the former compared to the latter. As a result, a single fuel cell based on an anode‐supported 20 μm thick samarium‐doped ceria electrolyte and BaSc_0.25Co_0.75O_3‐δ cathode achieved a very high peak power density of 1723 mW cm⁻² at 650 °C. We also demonstrated the possibility to increase the ORR activity of the BaSc_0.25Co_0.75O_3‐δ cathode by impregnation of a low amount of silver.

中文翻译：

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高氧非化学计量的BaSc0.25Co0.75O3-δ作为中温固体氧化物燃料电池的高性能阴极

降低固体氧化物燃料电池（SOFC）的工作温度是降低成本和延长寿命的高度期望，这取决于开发在较低温度下具有高氧还原反应（ORR）活性的阴极组件。在本文中，我们报道的高性能表征BASC _X钴_{1- X} ø _{3- δ}（X = 0，0.125，0.25和0.375）的钙钛矿型SOFC的阴极。不像BaCoO _{3- δ}，采用2H六方钙钛矿结构，更换25摩尔％的Co与钪稳定立方结构，这也导致在区域比电阻的显著减少和650和500℃之间的活化能（对于BaSc_0.25钴_0.75 ö _{3- δ}相对于非掺杂的BaCoO）_{3- δ}。在该温度范围内，BASC _0.25钴_0.75 ö _{3- δ}相比巴显示显着高的ORR活性_0.5锶_0.5钴_0.8的Fe _0.2 ø _3-δ（BSCF），当前阴极基准。我们认为这样的优越ORR性能BASC的更高的氧非化学计量_0.25钴_0.75 ö _{3 -δ}相对于BSCF，与前者相比，前者的氧体积扩散和表面交换系数也更高。其结果是，基于阳极支撑20μm厚钐掺杂的二氧化铈电解质和BASC单个燃料电池_0.25钴_0.75 ö _{3- δ}阴极实现的1723毫瓦cm的非常高的峰值功率密度^-2在650℃。我们还证明了通过浸渍少量银可以提高BaSc _0.25 Co _0.75 O3 _-δ阴极的ORR活性的可能性。