Geometric Properties of Nanostructured Solid Oxide Fuel Cell Electrodes
Geometric Properties of Nanostructured Solid Oxide Fuel Cell Electrodes
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DOI：
10.1149/2.057303jes
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发表时间：
2013
影响因子：
3.9
通讯作者：
Yanxiang Zhang;Qiong Sun;C. Xia;M. Ni
中科院分区：
文献类型：
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作者：
Yanxiang Zhang;Qiong Sun;C. Xia;M. Ni
采用现象学方法，对浸渍法制备的纳米固体氧化物燃料电池（SOFC）电极的三维微观结构进行了数值模拟。在不同的渗透负荷下，计算了所构建电极的关键几何性质，包括孔隙和渗透纳米颗粒的渗透概率、总和活性三相边界（TPB）长度、骨架和纳米颗粒的表面积以及骨架-纳米颗粒的边界面积。系统地研究了骨架粒径、骨架孔隙度、纳米颗粒粒径及其聚集风险的影响。建立了分析模型来预测这些几何特性，并与数值入渗结果和文献数据吻合良好。研究发现，当纳米颗粒渗透到骨架表面63%时，TPB长度达到峰值。更有趣的是，主链结构对纳米颗粒表面积的影响很小，但对TPB长度的影响很大，这提示了一种确定电极反应机制的策略。减小渗透颗粒尺寸会增加其表面积，增加峰值TPB长度，降低最佳渗透负荷，表明较小的渗透颗粒本质上有利于电极性能。研究结果为了解渗透SOFC电极的几何特性提供了有价值的信息，并有助于设计高性能SOFC电极。©2013电化学学会。[DOI: 10.1149/2.057303jes]版权所有2012年12月4日投稿；2013年1月3日收稿。出版于2013年1月19日。
3D microstructures for nanostructured solid oxide fuel cell (SOFC) electrodes fabricated by infiltration/impregnation method are constructed numerically, by using a phenomenological procedure. Key geometric properties of the constructed electrodes are calculated at various infiltration loadings, including the percolation probabilities of pores and infiltrated nanoparticles, the total and active three-phase boundary (TPB) length, backbone and nanoparticles surface areas, and backbone-nanoparticles boundary area. The effects of backbone particle size, backbone porosity, nanoparticle size, and its aggregation risk are studied systematically. Analytical models are developed to predict these geometric properties, and agree well with the numerical infiltration results, as well as the literature data. It is found that the peak TPB length can be achieved at 63% coverage of the backbone surface by infiltrated nanoparticles. More interestingly, the backbone structure has little effect on nanoparticles surface area, but significantly affects TPB length, suggesting an strategy to identify electrode reaction mechanisms. Decreasing infiltrated particle size increases its surface area, enhances the peak TPB length, and decreases the optimal infiltration loading, indicating small infiltrated particles essentially benefits electrode performance. The results provide valuable information for understanding the geometric properties of the infiltrated SOFC electrodes and contribute to the design of high performance SOFC electrodes. © 2013 The Electrochemical Society. [DOI: 10.1149/2.057303jes] All rights reserved. Manuscript submitted December 4, 2012; revised manuscript received January 3, 2013. Published January 19, 2013.