Gd2O3掺杂量对Ce1-xGdxO2-δ电解质导电性能的影响

Influence of Gd2O3 doping contents on conductivity of Ce1-xGdxO2-δelectrolyte

在500~700℃时,Gd2O3掺杂CeO2具有较高的离子电导率,从而被广泛应用于中温固体氧化物燃料电池(solid oxide fuel cell,SOFC)中.但在SOFC运行时,在电池的阳极侧Ce4+会被还原成Ce^3+,产生电子泄露现象,从而造成SOFC电池性能的衰减.采用溶胶-凝胶法成功制备Ce1-xGdxO2-δ(x=0.05,0.10,0.15,0.20,0.25,摩尔分数)固体电解质,研究不同Gd3+掺杂量对GDC电解质总电导率和电子电导率的影响,同时对总电导率、电子电导率与温度、氧分压之间的关系进行分析.结果表明:测试温度为750℃、Gd^3+掺杂量为0.20时,GDC电解质的总电导率最大,达到8.59×10^-2 S·cm^-1;电子电导率随着Gd^3+掺杂量的增大而降低,当Gd3+掺杂量为0.10、测试温度为750℃时,GDC电解质的电子电导率最大,为6.47×10^-4 S·cm^-1.Gd2O3掺杂量为0.20的GDC电解质具有最高的总电导率和较小的电子电导率,从而突显出最高的离子电导率.

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 Ce^3+ 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 Gd^3+ 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 Gd^3+ 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.