Influence of Gd2O3 doping contents on conductivity of Ce1-xGdxO2-δ electrolyte

Gd2O3 doped CeO2(GDC) was widely used in solid oxide fuel cell (SOFC) because of its high ionic conductivity at 500-700 ℃. However, during the SOFC operation, Ce4+ was reduced to Ce3+ at the anode side of the battery, resulting in electronic leakage, which leaded to the degradation of SOFC battery performance. The Ce1-xGdxO2-δ(x=0.05,0.10,0.15,0.20,0.25, mole fraction) solid electrolyte was prepared by sol-gel method. The effects of different Gd3+ doping amount on the total conductivity and electronic conductivity of GDC electrolyte were studied, and the relationships between the total conductivity, electronic conductivity, and temperature, oxygen partial pressure were analyzed. The results show that, when the Gd2O3 doping content is 0.20, the total conductivity of GDC reaches the highest 8.59×10-2 S·cm-1 at 750 ℃. The electronic conductivity decreases with the increase of Gd3+doping amount, and reaches the highest 6.47×10-4 S·cm-1 at 750 ℃ when Gd3+doping amount is 0.10. The GDC with doping amount of 0.20 highlights the highestionic conductivity because of its highest total conductivity and smaller electronic conductivity.