Two-step sintering ceria-based electrolytes

• Published in: International journal of hydrogen energy Vol. 35; no. 7; pp. 2737 - 2741
• Main Authors: Lapa, C.M., de Souza, D.P.F., Figueiredo, F.M.L., Marques, F.M.B.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2010; Elsevier
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Cations; Ceria; Diffraction; Dwell; Electrolytes; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Fuels; Gallium; Grain boundaries; Hydrogen; Microstructure; Sintering; Solid electrolytes; Solid oxide fuel cells; Yttrium; Solid oxide fuel cells; Solid electrolytes; Microstructure; Sintering; Ceria; Grain size; Scanning electron microscopy; Hydrogen; Solid electrolyte; Gadolinium; Cerium oxide; Solid oxide fuel cell; X ray diffractometry; Impedance; Yttrium; Electrochemical impedance spectroscopy
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2009.04.056

Yttrium and gadolinium-doped ceria-based electrolytes (20 at% dopant cation) with and without small Ga 2O 3-additions (0.5 mol%) were fired at peak temperatures of 1250 and 1300 °C, or following a two-step sintering profile including one peak temperature and subsequent dwell at 1150 °C, 10 h. All materials were characterized by scanning electron microscopy, X-ray diffraction and impedance spectroscopy in air, in the temperature range 200–800 °C. Average grain sizes in the range 150–250 nm and densifications up to about 94% were found dependent on the sintering profile and presence of Ga. The grain boundary arcs in the impedance spectra increased significantly with Ga-doping, cancelling the apparently positive role of Ga on bulk transport, evidenced mostly in the case of yttrium-doped materials.