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Understanding the sintering mechanism of Ni in a solid oxide fuel cell (SOFC) anode is one of the important issues to discuss the long-term durability of SOFC performance. The sintering behavior of Ni is affected not only by the operating temperature but also by the gas composition in the anode chamber. We analyzed the surface diffusion of a Ni adatom and Ni complexes on the Ni(111) surface under the operating temperature and gas compositions in the anode by using density functional theory. The Ni adatom, Ni-H and Ni-S complexes, which can be formed by H2 and H2S in anode gas, were considered as diffusion species on the Ni surface. It is theoretically confirmed that the formation of a NiS complex influences the sintering behavior of Ni depending on the temperature and the impurity H2S concentration in the fuel. Our calculated results are compared with the experimental observation on Ni sintering under various temperatures and H2S concentrations to find a good agreement. We clearly showed the important eff...

In this study, we propose a combination of molecular dynamics (MD) and the master sintering curve (MSC) approach to analyze the activation energy of sintering for porous materials. MD calculations ...

Microstructural change of porous electrodes in SOFC caused by sintering affected by materials and impurities is one of the main factors of the long-term degradation. Since it is difficult to clarify the effects of materials and impurities on sintering by experiments, atomistic scale simulation is important. In this study, we performed molecular dynamics (MD) simulation of porous structure of Ni and analyzed sintering properties of porous structure by employing master sintering curve theory. We have succeeded to obtain the sintering activation energy and its size dependency and to identify the dominant sintering mechanism by comparing sintering activation energy with activation energy of surface diffusion on each facet.

The prediction of long-term durability of SOFC anode is important to understand the sintering phenomena in the anode, which are affected by microstructure, materials, and impurities. To understand the sintering phenomena considering the effects of materials and chemical species, molecular dynamics (MD) simulation is one of the most effective computational methods. In this study, we developed a theoretical methodology based on the master sintering curve to analyze the sintering property. We performed MD simulation for the densification of both Ni and YSZ porous structures. The sintering activation energy obtained from our proposed method was in reasonable agreement with the experimental result.