Correlation between Phase Behavior and Electrical Conductivity of 10 mol % Y-Doped BaZrO3: An Anomalous Dispersion Effect-Aided Synchrotron Radiation XRD Study Combined with TEM Observation and Electrochemical Analysis
Correlation between Phase Behavior and Electrical Conductivity of 10 mol % Y-Doped BaZrO3: An Anomalous Dispersion Effect-Aided Synchrotron Radiation XRD Study Combined with TEM Observation and Electrochemical Analysis
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%20相%20行为%20和%20电%20电导率%20of%2010%20mol%20%%20Y掺杂%20BaZrO3之间的相关性%20:%20An%20异常%20色散%20效应辅助%20同步加速器%20辐射%20XRD%20研究%20综合%
DOI：
10.1021/acsami.8b19576
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发表时间：
2019
影响因子：
9.5
通讯作者：
Uda Tetsuya
中科院分区：
文献类型：
--
作者：
Han Donglin;Uda Tetsuya
钇掺杂的BaZrO 3（BZY）具有很高的质子导电性，是一种很有前途的中温燃料电池和电解质电池的候选电解质。然而，BZY的电导率在文献中有很大的差异。特别是对于BaZr0.9Y0.1O3−δ（BZY 10），报告的体电导率变化范围超过2个数量级。为了揭示原因，在这项工作中，我们进行了同步辐射X射线衍射分析BZY 10。将X射线调整到17.027 keV以接近Y-K吸收边（17.037 keV），从而激活异常色散效应以精确区分Zr和Y。还进行了高分辨率扫描透射电子显微镜观察和电化学测量。在这些实验结果的辅助下，Rietveld精修的质量得到了极大的提高，从而可以得到关于相行为和晶体结构的精确信息。结果表明，BZY 10样品在1600 °C烧结8 ~ 200 h后，具有双峰结构。它们不是单相，而是Y含量略有不同的两种钙钛矿相的混合物。烧结8h后两相中Y的含量分别为12.3和8.7mol%，烧结200 h后分别为10.6和9.2mol%。此外，在Ba和Zr的网站上的Y的分区没有建议，虽然小的Ba不足约0.05形成在样品烧结40小时或更长时间。但值得注意的是，Ba空位的形成被合理地认为是体电导率和晶界电导率降低的可能原因。
Y-doped BaZrO3(BZY) has high proton conductivity and is a promising electrolyte candidate for fuel cells and electrolytic cells at an intermediate temperature range. However, the conductivity of BZY has a large discrepancy in the literature. In particular, for BaZr0.9Y0.1O3−δ(BZY10), the reported bulk conductivity varies in the range of more than 2 orders of magnitude. With the aim of revealing the reason, in this work, we conducted synchrotron radiation X-ray diffraction analysis on a BZY10. The X-ray was adjusted to 17.027 keV to approach the Y-K absorption edge (17.037 keV), and the anomalous dispersion effect was thereby activated for a precise distinction between Zr and Y. High-resolution scanning transmission electron microscopy observation and electrochemical measurements were also performed. Assisted by these experimental results, Rietveld refinement with greatly improved quality was thereby available to generate precise information on both the phase behavior and crystal structure. The results revealed that the BZY10 samples after sintering at 1600 °C for 8 to 200 h have a bimodal microstructure. They were not single phases, but mixtures of two perovskite phases differing slightly in Y contents. The Y contents in the two phases after sintering for 8 h were about 12.3 and 8.7 mol %, respectively, and finally became 10.6 and 9.2 mol %, respectively, after sintering for 200 h. In addition, the partition of Y over both the Ba and Zr sites was not suggested, although small Ba-deficiency around 0.05 formed in the sample sintered for 40 h or longer. But notably, the formation of the Ba vacancies is reasonably believed as the possible reason for the decrease in bulk and also grain boundary conductivities.