Solid oxide electrolysis cells (SOECs) use electricity and steam to produce hydrogen at high temperature. In a symmetric cell, the same electrode material is used on both sides. This simplifies manufacturing, removes the need for an external hydrogen supply and avoids nickel, a critical raw material.
We developed electrodes based on Sr2Fe1.5Mo0.5O6-δ (SFM) and took them from small button cells to large 30 cm² cells and a short stack. Button cells reached 0.8 A cm⁻² in steam electrolysis at 850 °C and ran stably for up to 800 hours. The short-stack prototype confirmed that the concept can be scaled up for hydrogen production.
The work was carried out with Repsol Technology Lab and Técnicas Reunidas.
Read the paper: V. Kolotygin, W. Zambelli, K. Toala, L. Bernadet, A. Maria, A. Martínez, B. Moreno, N. Bausá, Á. García, M. Torrell, A. Tarancón, “High performance solid oxide electrolysis large-area cells and stacks based on symmetric Sr2Fe1.5Mo0.5O6-δ electrodes”, International Journal of Hydrogen Energy 280, 157702 (2026). https://doi.org/10.1016/j.ijhydene.2026.157702
Figure from Kolotygin et al., Int. J. Hydrogen Energy 280, 157702 (2026), CC BY-NC-ND 4.0.
