Solid Oxide Electrolyzer (SOEC)

SOEC are produced at ISTEC starting from powders obtained by conventional solid state synthesis or chemical routes (precipitation, sol-gel, etc.). The powders are synthesized with characteristics suitable for the subsequent shaping processes. The cell fabrication consists in depositing the cell elements onto a supporting-element produced by tape casting. All the possible substrates for SOEC were produced with this technique:

anodes: La0.6Sr0.4Fe0.8Co0.2O3 (LSCF), La0.8Sr0.2MnO3 (LSM);

cathodes: NiO/(Zr,Y)O2, NiO/Ce0.8Gd0.2O2, NiO/ Ba(Ce,Y,Zr)O3;

electrolytes: (Zr,Y)O2, Ce0.8Gd0.2O2.

Products with dimensions up to 15x15 cm were obtained after the thermal treatment needed to reach a suitable densification or porosity level for the electrolyte or the electrodes respectively.

The other layers are applied onto the tape cast supporting element via screen printing and or atmospheric spray. These technique have been for their low cost and easy scalability. The half-cell (supporting element-electrolyte) is generally sintered via co-firing treatment in order to lower the costs and simplify the production process. To obtain the complete cell (supporting element/electrolyte/electrode - Figure) a further thermal treatment is necessary after the deposition of the second electrode. To reduce the production steps and therefore the costs, ISTEC has developed for the first time a complete co-firing process that allows the production of the complete cell in a single heat treatment of the starting powders.