Study On Preparation And Properties Of Doped CeO₂ Electrolyte

Doped ceria-based (Sm0.2Ce0.8 O1.9 , SDC) solid electrolyte was prepared by low-temperature combustion method. The synthesis technology and the electrical conductivity of the electrolyte were studied. The effect of bismuth oxide content (0.5;1;2;3;4;5 wt%) on the sintering characteristics and electrochemical property of SDC (Sm0.2Ce0.8 O1.9)was investigated. The pretreatment temperature of Bi-SDC at 800℃and sintering temperature at 1250℃were determined from the thermal expansion curves. The phase structure was analyzed by the X-ray diffraction (XRD). The cubic fluorite structure and no new phase where found after doping bismuth oxide. AC conductivity was measured on bulk materials and the conductivity of SDC doping bismuth oxide below 5 wt% was higher than that of SDC sintered at 1600℃. The impact on the electrolyte conductivity was mainly by improving the grain-boundary electrical conductivity. Sm0.2-xBixCe1.9 (x = 0,0.05,0.1,0.15,0.2) were synthesized by low temperature combustion method. The electrical properties were studied.Bi3+ had a notably significant effect on the grain boundaries electrolyte conductivity than grain. The impact on the electrolyte conductivity is mainly by improving the grain-boundary conductivity. After the addition of Bi3+, the structure of space-charge layer for the electrolyte, so that the activation energy of grain boundary conductivity decreased and grain boundary conductivity increased.