Characterization of High Density CeO2-Based Electrolyte

A. Arabac i Istanbul University-Cerrahpasa, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Avcilar, 34320 Istanbul, Turkey

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Co-doped ceria electrolytes of the Ce0.80Nd0.2-xSmxO1.90 (x=0.05, 0.10, and 0.20) powders were prepared with the Pechini method. The aim of the present investigation was to study the effect of co-doping on the ionic conductivity of ceria (CeO2) for its use as solid electrolyte in intermediate temperature solid oxide fuel cells. Results of the X-ray diffraction analyses showed that all powders calcined at 600° for 4 h were single phase with cubic fluorite structure. The average crystallite sizes calculated by the Scherrer formula were found as between 24 and 30 nm. The samples were sintered at 1400° for 6 h to obtain dense ceramics (over 93%). The two-probe a.c. impedance spectroscopy was used to study the ionic conductivity of the co-doped ceria samples. Effects of co-doping on crystal structure and electrical conductivity were studied comparing with the single doping. The results indicated that Ce0.80Nd0.10Sm0.10O1.90 had the highest electrical conductivity, σ750° which is equal to 4.42×10-2 S/cm. It can be therefore concluded that co-doping with Sm3+ and Nd3+ cations can further improve the electrical properties of ceria electrolytes compared to single element doped ceria (Ce0.80Sm0.20O1.90).

DOI:10.12693/APhysPolA.135.571 topics: SOFC, co-doped ceria, electrolyte, SEM