Low-temperature deposition of undoped ceria thin films in scCO2 as improved interlayers for IT-SOFC

David Mesguich (1, 2) , Cyril Aymonier (1) , Jean-Marc. Bassat (1) , Fabrice Mauvy (1) , Eunyoung You (2, 3) , James J. Watkins (2)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 Polymer Science and Engineering Department
3 Chemical Engineering Department

Cerium oxide films were deposited onto various yttria-stabilized zirconia (YSZ) electrolytes using supercritical fluid deposition (SFD) in a cold wall reactor. Deposition of ceria thin films (20-240 nm) was carried out via hydrolysis of a Ce precursor at 250-300 °C (typically 30 min) in supercritical CO₂ (scCO₂). The as-deposited films were continuous, dense and crystalline. They exhibited some carbon contamination which was eliminated in all cases by postannealing the films at 400 °C. Film microstructure depends on the hydrolysis conditions (water to cerium molar ratio), on the substrate nature (Si wafers or YSZ pellets) and on the YSZ pellet thickness (100 μm or 1 mm). Ceria films were then used as interlayers for intermediate temperature solid oxide fuel cells (IT-SOFC) between the YSZ electrolyte and the Nd₂NiO_4+δ cathode layer subsequently deposited. The electrochemical properties of the SOFC symmetrical half cells were investigated by electrochemical impedance spectroscopy (EIS). The presence of the undoped ceria layer deposited in scCO₂ lowers the resistance of the cell, compared both to cells with an optimized doped ceria layer deposited by screen printing and to cells without any interlayer.

Mots clés: Solid oxide fuel cells; Low temperature; Conformal deposition; ASR resistance; Interlayer; Ceria; Deposition; Supercritical fluids

Domaines: Matériaux

David Mesguich, Cyril Aymonier, Jean-Marc. Bassat, Fabrice Mauvy, Eunyoung You, et al.. Low-temperature deposition of undoped ceria thin films in scCO2 as improved interlayers for IT-SOFC. Chemistry of Materials, 2011, 23 (24), pp.5323-5330. ⟨10.1021/cm2012846⟩. ⟨hal-00654561⟩