Development of thin electrode layers by spray coating for solid oxide cells

This study investigates the innovative use of a deposition technique, spray coating, for the fabrication of optimal thicknesses of solid oxide cell (SOC) layers on a range of SOC-compatible materials. The work has been carried out as part of the European KEROGREEN project that aims to utilize CO 2 into sustainable aircraft kerosene. To separate the oxygen at higher operating temperatures after CO 2 dissociation (plasmolysis) for creating a CO stream for Fischer–Tropsch downstream synthesis, a solid oxide electrolyzer cell is used. For the electrodes, the most promising LaSr-based perovskite materials were selected based on their electrical conductivity and ability to suppress the CO to CO 2 back reaction at the CO 2 (plasma) splitting side. The spray-coating suspension was adjusted to improve the adhesion and quality of the adjacent SOC layers. The electrode coatings showed good adhesion to the yttria-stabilized zirconia electrolyte, with a thickness of 10–15 µm and porosity of circa 45%. Prior to the electrodes, thin and dense interlayers were spray coated to prevent reactions between the electrolyte and the electrodes. These interlayers reduced the total electrodes resistance of the SOEC. The LaSr-based CO 2 electrode powder and spray-coated SOEC remained stable in the CO 2 /CO/O 2 environment.