In the present study, two Ni/YSZ anodes with different volume ratios of Ni and YSZ, 30: 70 and 45: 55 vol%, are operated in dry methane under open circuit and polarized conditions. Three-dimensional (3D) Ni/YSZ microstructures after carbon deposition are reconstructed by the focused ion beam-scanning electron microscopy (FIB-SEM) with the help of machine learning segmentation. From the reconstructed mircostructures, volume fraction, connectivity, three phase boundary (TPB) density, and tortuosity are quantified. In addition, local carbon microstructures are quantitatively reconstructed, and the effect of polarization on carbon morphology is investigated. It is demonstrated that Ni surface in the vicinity of active TPB near the electrolyte is free from carbon formation, while remaining Ni surface at some distances from TPB exhibits severe carbon deposition. In average, total amount of carbon deposition is larger near the electrolyte. These observations imply complex interplay between the electrochemical steam generation and methane cracking on Ni surface which take place very locally near the active TPB.

在本研究中，两种 Ni/YSZ 阳极具有不同的 Ni 和 YSZ 体积比（30: 70 和 45: 55 vol%），在开路和极化条件下在干燥甲烷中运行。碳沉积后的三维 (3D) Ni/YSZ 微观结构通过聚焦离子束扫描电子显微镜 (FIB-SEM) 在机器学习分割的帮助下重建。根据重建的微观结构，对体积分数、连通性、三相边界 (TPB) 密度和弯曲度进行量化。此外，定量重建了局部碳微观结构，并研究了极化对碳形态的影响。结果表明，靠近电解质的活性TPB附近的Ni表面没有碳形成，而距 TPB 一定距离处的剩余 Ni 表面则表现出严重的积碳。平均而言，靠近电解质的积碳总量较大。这些观察结果表明电化学蒸汽产生和镍表面甲烷裂解之间存在复杂的相互作用，这种相互作用发生在活性TPB 附近的局部区域。