Sulfur‐Enhanced Performance and Durability of SrFe 0.75 Mo 0.25 O 3− δ /Ce 0.9 Gd 0.1 O 2− δ Fuel Electrodes for Solid Oxide Fuel Cell

Solid oxide fuel cells (SOFCs) are a key technology for highly efficient, low‐emission power generation from hydrogen and hydrocarbon‐based fuels. However, conventional Ni‐cermet fuel electrodes show high performance and stability but exhibit poor tolerance toward impurities, particularly sulfur. Here, the performance and durability of Ni‐free perovskite‐based SrFe 0.75 Mo 0.25 O 3− δ (SFM)/Ce 0.9 Gd 0.1 O 2− δ (CGO) composite fuel electrodes are evaluated under hydrogen‐rich conditions, with and without trace hydrogen sulfide in the fuel. Electrolyte‐supported cells with SFM/CGO show initial performance comparable to that of benchmark Ni/CGO electrodes at 800 °C. Despite similar ohmic resistance, cells with SFM/CGO exhibit higher polarization resistance, suggesting slightly reduced electro‐catalytic activity. Durability testing reveals significant degradation of SFM/CGO over time, attributed to SFM phase decomposition in hydrogen‐rich atmospheres and microstructural reorganization based on post‐test analysis. Surprisingly, the addition of ppm‐level H 2 S not only mitigated degradation, but also improved electrode performance. These results uncover a counterintuitive, sulfur‐mediated stabilization mechanism for SFM‐based electrodes, offering a new development pathway toward sulfur‐tolerant, nickel‐free SOFCs for robust and fuel‐flexible energy conversion.