Optimizing Ionic Transport in Metal-Supported Solid Oxide Fuel Cells: Influence of Electrolyte Thickness

Metal-supported solid oxide fuel cells (MS-SOFCs) represent a promising advancement for intermediate-temperature energy conversion applications due to their enhanced mechanical robustness and rapid startup capabilities. This investigation systematically evaluates the correlation between yttria-stabilized zirconia (8YSZ) electrolyte thickness and electrochemical performance in Ni-Fe supported architectures. Three distinct cells featuring YSZ electrolyte thicknesses of 7.05, 14.2, and 21.2 μm were fabricated via tape casting and co-sintering at 1350°C, maintaining identical Ni-Fe support (280 μm) and Ni-YSZ anode (22 μm) thicknesses. Electrochemical characterizations revealed a clear inverse relationship between electrolyte thickness and cell performance. The cell with the thinnest electrolyte (7.05 μm) achieved the highest power density of 0.32 W/cm² at 800°C, representing a 4.6-fold improvement compared to the thickest variant (21.2 μm). Electrochemical Impedance Spectroscopy and Distribution of Relaxation Times analysis confirmed that ohmic resistance dominated the total cell impedance, scaling linearly with electrolyte thickness while electrode kinetics remained consistent. This study establishes that thin YSZ electrolytes (≤8 μm) maximize MS-SOFC performance while maintaining structural integrity through co-sintering fabrication, providing an essential design for high-performance metal-supported fuel cell development.