High performance solid oxide electrolysis large-area cells and stacks based on symmetric Sr2Fe1.5Mo0.5O6-δ electrodes

Sr 2 Fe 1.5 Mo 0.5 O 6-δ (SFM)-based materials were investigated as electrodes for solid oxide electrolysis cells (SOECs) in a symmetric configuration, spanning from button cells to short-stack prototypes. At the button-cell level, optimized configurations with composite SFM-based electrodes achieved area-specific resistances of 0.4-0.7 Ω cm 2 and steam electrolysis current densities of 0.8 A cm −2 at 850 °C, with stable operation for up to 800 h and degradation rates of ∼7%·kh −1 at 0.45 A cm −2 . Upscaling the electrode area to 30 cm 2 yielded 0.5-0.6 A cm −2 at 850 °C, with performance partially limited by current collection. Integration into a short-stack with interconnectors and compressive sealants demonstrated the feasibility of the symmetric-cell concept and highlighted the upscaling potential of this technology for electrolysis applications. The symmetric-cell approach simplifies manufacturing, eliminates the need for external hydrogen supply, and reduces reliance on critical raw materials, underscoring the relevance of this work for sustainable SOEC development.