Thermally driven long–distance elemental diffusion enhances the sinterability of anode and electrolyte of metal–supported solid oxide fuel cells

Metal–supported solid oxide fuel cells (SOFCs) have the merits of quick startup, low cost, and excellent robustness, however, there is a lack of understanding on the effect of thermally driven elemental diffusion. Herein, we investigate the role of elemental diffusion on the evolution of morphologies and electrochemical performance of Ni–Fe alloy supported Ni–yttria stabilized zirconia (YSZ) anode and YSZ electrolyte film. The results show that during the co–sintering process at high temperatures, there is significant diffusion of Fe element from the Ni–Fe oxide substrate to the anode and electrolyte. The elemental diffusion leads to the formation of a NiO core/NiFe₂O₄ shell structure in the anode and dissolution of Fe cations in the YSZ lattices of anode and electrolyte, but also significantly enhances the sinterability of both layers. The negative effect of Fe diffusion induced microstructure coarsening is largely compensated by the formation of an electrocatalytically active Ni–Fe alloy in the reduced anode. The present work provides insights into the design and development of efficient metal–supported SOFCs by taking advantage of elemental diffusion.