Multi-nanoparticle model simulations of the porosity effect on sintering processes in Ni/YSZ and Ni/ScSZ by the molecular dynamics method
Multi-nanoparticle model simulations of the porosity effect on sintering processes in Ni/YSZ and Ni/ScSZ by the molecular dynamics method
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DOI：
10.1039/c5ta05575j
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发表时间：
2015-10
影响因子：
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通讯作者：
Jingxiang Xu;S. Bai;Y. Higuchi;N. Ozawa;Kazuhisa Sato;T. Hashida;M. Kubo
中科院分区：
文献类型：
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作者：
Jingxiang Xu;S. Bai;Y. Higuchi;N. Ozawa;Kazuhisa Sato;T. Hashida;M. Kubo
了解多孔阳极的烧结机理对于开发适用于固体氧化物燃料电池的耐用阳极是必要的。为此目的，开发了基于分子动力学（MD）计算的多纳米颗粒烧结模拟方法[J. Xu等人，J. Phys. Chem. C，2013，117，9663-9672]。该方法可以用来计算的多孔结构的性能，如孔隙率和框架结构，对烧结的影响，不同于以往的烧结模拟与传统的纳米粒子模型。我们发现，在Ni/YSZ多孔阳极中，YSZ纳米颗粒框架通过破坏两个Ni纳米颗粒之间的颈部的生长来抑制Ni纳米颗粒的烧结。在本文中，我们使用我们的方法来揭示陶瓷类型对烧结过程的影响。我们研究了Ni/YSZ和Ni/ScSZ阳极的烧结和降解过程之间的差异。在模拟中，Ni/ScSZ中Ni纳米颗粒的烧结程度小于Ni/YSZ中的烧结程度。Ni对ScSZ纳米颗粒的粘附性比对YSZ纳米颗粒的粘附性更强，防止了Ni/ScSZ阳极中的Ni纳米颗粒彼此接近，抑制了烧结。我们的多纳米颗粒烧结MD模拟揭示了Ni/YSZ和Ni/ScSZ阳极中Ni纳米颗粒的不同烧结过程。我们还研究了烧结对降解的影响。随着烧结程度的增加，氢的吸附位和氢氧化的电化学反应位减少。观察到Ni/ScSZ阳极相对于Ni/YSZ阳极的低降解。此外，我们显示了在Ni/YSZ和Ni/ScSZ的烧结引起的降解的孔隙率的影响，并找到了最佳的孔隙率。这些发现不能通过传统的两个或三个纳米颗粒烧结MD模拟。我们的多纳米颗粒烧结模拟方法可用于揭示适合抑制阳极烧结和降解的陶瓷类型，并可用于设计耐用的阳极。
Understanding the sintering mechanism in porous anodes is necessary for developing durable anodes suitable for use in solid oxide fuel cells. A multi-nanoparticle sintering simulation method based on molecular dynamics (MD) calculation was developed for this purpose [J. Xu et al., J. Phys. Chem. C, 2013, 117, 9663–9672]. The method can be used to calculate the effect of the porous structure properties, such as the porosity and framework structure, on the sintering, unlike previous sintering simulations with conventional nanoparticle models. We revealed that, in a Ni/YSZ porous anode, the YSZ nanoparticle framework suppresses sintering of Ni nanoparticles by disrupting the growth of the neck between two Ni nanoparticles. In this paper, we used our method to reveal the effect of ceramic type on the sintering processes. We investigated the difference between the sintering and degradation processes in Ni/YSZ and Ni/ScSZ anodes. In the simulation, the degree of sintering of the Ni nanoparticles in Ni/ScSZ was smaller than that in Ni/YSZ. The stronger adhesion of Ni to ScSZ nanoparticles than to YSZ nanoparticles prevented the Ni nanoparticles from approaching each other in the Ni/ScSZ anode, inhibiting sintering. Our multi-nanoparticle sintering MD simulations revealed the different sintering processes for Ni nanoparticles in Ni/YSZ and Ni/ScSZ anodes. We also investigated the effect of sintering on degradation. The hydrogen adsorption sites and electrochemical reaction sites of the hydrogen oxidation decreased as the degree of sintering increased. A low degradation of the Ni/ScSZ anode relative to that of the Ni/YSZ anode was observed. Furthermore, we showed the effect of porosity on degradation induced by sintering in Ni/YSZ and Ni/ScSZ, and found an optimal porosity. These findings cannot be obtained by conventional two- or three-nanoparticle sintering MD simulations. Our multi-nanoparticle sintering simulation method is useful for revealing the types of ceramics suitable for inhibiting sintering and degradation in anodes, and can be used to design durable anodes.