Long-term electrochemical characterization of novel Sr2FeMo0.65Ni0.35O6−δ fuel electrode for high-temperature steam electrolysis in solid oxide cells

• Durability of SFMNi is reported for the first time up to 500 h at −0.5 A cm −2 . • Higher performance than Ni-8YSZ and Ni-GDC fuel electrodes (1.5 V, 900 °C). • Degradation rate is lower than reported for Ni-8YSZ and Ni-GDC fuel electrodes. The present study focuses on the highly catalytic double-perovskite Sr 2 FeMo 0.65 Ni 0.35 O 6−δ (SFMNi) fuel electrode material for Solid Oxide Electrolysis Cells (SOECs). The electrolyte-supported single button cells with the highly active SFMNi fuel electrode were electrochemically characterized between 900 °C down to 750 °C in steam and co-electrolysis conditions using DC- and AC-techniques. The cells achieved current densities of −1.62 A cm −2 and −1.74 A cm −2 at 900 °C under steam and co-electrolysis conditions, respectively, exceeding the performance of cells with Ni-8YSZ fuel electrodes by ∼65–79 % and Ni-GDC fuel electrodes by 24–28 %. The post-test SEM-EDX analyses of the as-prepared and tested cells’ cross-section showed increased pore formation and particle growth of the SFMNi fuel electrode after testing in the humidified atmosphere for 500 h.