Ultrasound assisted synthesis of Gd and Nd doped ceria electrolyte for solid oxide fuel cells

Abstract In this study, the ceramic powders of Ce 1− x Gd x O 2− x /2 and Ce 1− x Nd x O 2− x /2 ( x =0.05, 0.10, 0.15, 0.20 and 0.25) were synthesized by ultrasound assisted co-precipitation method. The ionic conductivity was studied as a function of dopant concentration over the temperature range of 300–800 °C in air, using the impedance spectroscopy. The maximum ionic conductivity, σ 800 °C =4.01×10 −2 Scm −1 with the activation energy, E a =0.828 kJmol −1 and σ 800 °C =3.80×10 −2 Scm −1 with the activation energy, E a =0.838 kJmol −1 were obtained for Ce 0.90 Gd 0.10 O 1.95 and Ce 0.85 Nd 0.15 O 1.925 electrolytes, respectively. The average grain size was found to be in the range of 0.3–0.6 μm for gadolinium doped ceria and 0.2–0.4 μm for neodymium doped ceria. The uniformly fine crystallite sizes (average 12–13 nm) of the ultrasound assisted prepared powders enabled sintering of the samples into highly dense (over 95%) ceramic pellets at 1200 °C (5 °C min −1 ) for 6 h.