ZHOU Ming, GE Lin, LI Ruifeng, GUO Lucun

(College of Materials Science and Engineering, Nanjing University of Technology, Nanjing Jiangxi 210009, China)

Abstract:The ceria-based (1-x)(CeO2)0.92 (Y2O3)0.06 (La2O3)0.02+xCoO1.5 (x=0, 0.5 mol%, 1mol% and 2mol%) solid electrolyte materials were prepared by solid state reaction method and sintered at different temperatures. The crystal structure, volume density, ionic conductivity and thermal expansion were measured by X-ray diffraction (XRD), Archimedes method, alternating current (AC) impedance spectroscopy and dilatometry, respectively. The results show that the samples with Co doping exhibit single cubic fluorite structure phase after sintering at 1500℃, Co can effectively promote the sinterability of the samples, decreasing the sintering temperature by 100℃. It is also found that the grain boundary conductivities of the samples are improved with the increase of Co content and the sample with 2mol% Co doping has the highest conductivity of 0.051s·cm-1 at 700℃. Furthermore, the effect of Co doping on the thermal expansion is insignificant.

Key words:ceria-based electrolyte; sinterability; ionic conductivity; thermal expansion