The ytterbia and alumina co-doped zirconia electrolyte materials were synthsized by a solid-state method. The results revealed that Al_2O_3-doping was beneficial for sintering and increasing flexural strength.The effect of Al_2O_3-doping on ionic conductivity was in relation to the doping content of ytterbia.Only the ionic conductivity of sample with 6% (mole fraction)Yb_2O_3 was enhanced by alumina doping.6%(mole fraction)Yb_2O_3 and 0.5%(mole fraction)Al_2O_3 codoped zirconia electrolyte showed excellent bending strength and the best oxygen ionic conductivity.A maximum density of 0.40W/cm~2 was measured at 800℃ for the cell with this material as electrolyte
