Minimized thermal expansion mismatch of cobalt-based perovskite air electrodes for solid oxide cells,Nanoscale

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Minimized thermal expansion mismatch of cobalt-based perovskite air electrodes for solid oxide cells
Nanoscale ( IF 5.8 ) Pub Date : 2021-11-15 , DOI: 10.1039/d1nr06845h
Zhishan Li ₁ , Meilan Peng ₁ , Yingru Zhao ₁ , Jianhui Li ₂ , Yifei Sun _{1,

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Affiliation

The mismatch of thermal expansion coefficients (TECs) between cobalt-containing perovskite air electrodes and electrolytes is a great challenge for the development of thermo-mechanically durable solid oxide cells (SOCs). In this work, we propose a facile design principle to directly grow highly dispersed Co reactive sites onto ion-conducting scaffolds and confine the dimension of active centres within nanoscale. As a representative, the Co-socketed BaCe_0.7Zr_0.2Y_0.1O_3−δ perovskite (denoted as R-BCZY-Co) was constructed via a consecutive sol–gel and in situ exsolution approach. Combined XRD, H₂-TPR, SEM and TEM results confirm the emergence of Co nanoparticles on a BCZY matrix without the segregation of a secondary Co-rich phase. The symmetric half-cell measurement suggests that R-BCZY-Co air electrode with the optimal Co content of 10 mol% exhibits a 7-fold promoted oxygen activation performance with a polarization resistance of ∼0.17 Ω cm² at 750 °C. The TEC mismatch between fabricated R-BCZY-Co electrodes and BCZY electrolytes is minimized down to only ∼11.4%, which is significantly lower than that of other representative counterparts. Moreover, the detailed XPS result proves that the architecture of exsolved Co on BCZY possesses a higher concentration of surface oxygen vacancy, which further benefits the kinetics of ion diffusion and oxygen absorption.

中文翻译：

用于固体氧化物电池的钴基钙钛矿空气电极的热膨胀失配最小化

含钴钙钛矿空气电极和电解质之间热膨胀系数 (TEC) 的不匹配是开发热机械耐用固体氧化物电池 (SOC) 的巨大挑战。在这项工作中，我们提出了一种简单的设计原则，将高度分散的 Co 反应位点直接生长到离子导电支架上，并将活性中心的尺寸限制在纳米尺度内。作为代表，Co-socketed BaCe _0.7 Zr _0.2 Y _0.1 O _{3− δ}钙钛矿（表示为 R-BCZY-Co）是通过连续溶胶-凝胶和原位溶出方法构建的。结合XRD，H ₂-TPR、SEM 和 TEM 结果证实 Co 纳米颗粒出现在 BCZY 基体上，而没有分离出二次富 Co 相。对称半电池测量表明，最佳 Co 含量为 10 mol% 的 R-BCZY-Co 空气电极在 750°C 下表现出 7 倍促进的氧活化性能，极化电阻为 ~0.17 Ω cm ²。制造的 R-BCZY-Co 电极和 BCZY 电解质之间的 TEC 失配被最小化到仅 ~11.4%，这显着低于其他代表性对应物。此外，详细的 XPS 结果证明 BCZY 上的外溶 Co 结构具有更高浓度的表面氧空位，这进一步有利于离子扩散和氧吸收的动力学。

更新日期：2021-11-30

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