Chromium-diffusion-induced degradation in metal-supported solid oxide fuel cells with porous stainless-steel supports

The degradation mechanisms in metal-supported solid oxide fuel cells (MS-SOFCs) are investigated through long-term durability testing and oxidation analysis of porous stainless steel under a humidified hydrogen atmosphere. An MS-SOFC fabricated using 1C44Mo29 steel undergoes a durability test for 8400 h, resulting in a degradation rate of 5.2 %/1000h. Post-test analysis reveals breakaway oxidation of fine alloy particles at the interface between the zirconia-based anode backbone and metal support, along with Ni-Cr formation within the anode, which potentially increases ohmic resistance and hydrogen oxidation polarization resistance. To analyze the correlation between microstructural changes and the electrical resistance of porous stainless steel, a volumetric segmentation scheme is developed using a deep learning model applied to three-dimensional reconstructions from plasma focused ion beam scanning electron microscopy. The results demonstrate that the contribution of metal support oxidation to the overall cell performance is only 7.3 mΩcm2 even after 8400 h under 50% H₂-50% H₂O, indicating a minimal impact on cell performance; however, Cr depletion in the metal support can cause detrimental degradation.