Atomistic simulations of anisotropic mechanical behavior in non‐stoichiometric gadolinia‐doped ceria solid electrolytes,International Journal of Energy Research

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Atomistic simulations of anisotropic mechanical behavior in non‐stoichiometric gadolinia‐doped ceria solid electrolytes
International Journal of Energy Research ( IF 4.3 ) Pub Date : 2020-02-07 , DOI: 10.1002/er.5105
Tianyu Guan ₁ , Zhiqiang Yang ₁ , Yi Sun ₁ , Yuhang Jing ₁ , Wenfeng Guo ₂

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Gadolinia‐doped ceria (GDC), as an electrolyte of solid oxide fuel cells, reduces its mechanical property when exposed to reducing conditions. In this paper, the anisotropic mechanical behavior of non‐stoichiometric GDC solid electrolytes is investigated by using the molecular dynamics (MD) method. It is found that the oxygen vacancies whether from doping Gd³⁺ ions or generating Ce³⁺ ions by reduction have a serious impact on the mechanical properties such as phase transformation and fracture strength. The defect‐dependent tensile strength is observed to be consistent with reported experimental measurements. Moreover, increasing temperature reduces the fracture strength. The influence of temperature on the critical nucleation stress and the fluorite phase strength is further analyzed. Beyond that, GDC undergoes volumetric expansion due to non‐stoichiometric effects. The linear chemical strain and coefficient of compositional expansion (CCE) are calculated and compared with the experimental results.

中文翻译：

非化学计量掺杂g的二氧化铈固体电解质各向异性力学行为的原子模拟

掺杂氧化d的二氧化铈（GDC）作为固体氧化物燃料电池的电解质，在还原条件下会降低其机械性能。本文通过分子动力学（MD）方法研究了非化学计量GDC固体电解质的各向异性力学行为。发现掺杂Gd ³⁺离子或生成Ce ³⁺引起的氧空位还原产生的离子严重影响机械性能，如相变和断裂强度。观察到与缺陷有关的拉伸强度与报告的实验测量结果一致。而且，升高温度降低了断裂强度。进一步分析了温度对临界形核应力和萤石相强度的影响。除此之外，由于非化学计量效应，GDC经历了体积膨胀。计算了线性化学应变和组成膨胀系数（CCE），并与实验结果进行了比较。

更新日期：2020-02-07

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