Layered YSZ/SCSZ/YSZ Electrolytes for Intermediate Temperature SOFC Part I: Design and Manufacturing
Chemical Engineering, Applied Mechanics
(Sc2O3)0.1(CeO2)0.01(ZrO2)0.89 (SCSZ) ceramic electrolyte has superior ionic conductivity in the intermediate temperature range (700–800 °C), but it does not exhibit good phase and chemical stability in comparison with 8 mol% Y2O3–ZrO2 (YSZ). To maintain high ionic conductivity and improve the stability in the whole electrolyte, layered structures with YSZ outer layers and SCSZ inner layers were designed. Because of a mismatch of coefficients of thermal expansion and Young's moduli of SCSZ and YSZ phases, upon cooling of the electrolytes after sintering, thermal residual stresses will arise, leading to a possible strengthening of the layered composite and, therefore, an increase in the reliability of the electrolyte. Laminated electrolytes with three, four, and six layers design were manufactured using tape-casting, lamination, and sintering techniques. After sintering, while the thickness of YSZ outer layers remained constant at ∼30 μm, the thickness of the SCSZ inner layer varied from ∼30 μm for a Y–SC–Y three-layered electrolyte, ∼60 μm for a Y–2SC–Y four-layered electrolyte, and ∼120 μm for a Y–4SC–Y six-layered electrolyte. The microstructure, crystal structure, impurities present, and the density of the sintered electrolytes were characterized by scanning and transmission electron microscopy, X-ray and neutron diffraction, secondary ion mass spectroscopy, and water immersion techniques.
Postprint version. Published in Fuel Cells, Volume 12, Issue 5, 2012, pages 722-731.
© Fuel Cells, 2012, Wiley Online Library
Chen, Y., Orlovskaya, N., Klimov, M., Huang, X., Cullen, D., Graule, T., Kuebler, J. (2012). Layered YSZ/SCSZ/YSZ Electrolytes for Intermediate Temperature SOFC Part I: Design and Manufacturing. Fuel Cells, 12(5), 722-731.