Sulfur-Enhanced Performance and Durability of SrFe0.75Mo0.25O3-d/Ce0.9Gd0.1O2-d Fuel Electrodes for Solid Oxide Fuel Cell

Kurzfassung

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 SrFe0.75Mo0.25O3−d (SFM)/Ce0.9Gd0.1O2−d (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 H2S 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.