钆掺杂氧化铈固体电解质低温电性能的研究

Study on the Electrical Properties of Gd-doped Ceria Solid Electrolyte at Low Temperature

采用固相反应法成功制备了电解质Ce_(0.8)Gd_(0.2)O_(1.9)(CGO)。在250℃～600℃范围内利用交流阻抗谱技术测试了分别以Pt和Ag作电极的CGO的导电性能和界面行为,探讨了低温下电导率与温度,界面电阻与温度和频率等之间的关系;并对O_2在电极表面的扩散机理进行研究。结果表明,用Pt或Ag作电极时,晶粒、晶界和总电导率与温度均严格遵守Arrhenius公式,CGO(Pt)的电导活化能E_a分别为0.41,0.51,0.42eV,CGO(Ag)的电导活化能Ea分别为0.43,0.55,0.42eV:晶界阻抗半圆中的特征频率与温度也均符合Arrhenius公式;Pt(Ag)/CGO的界面阻抗主要来自氧的扩散阻抗,其扩散活化能分别为0.32eV和0.52eV。

The electrolyte, Ceo.sGdo.201.9 （CGO）, was successfully prepared by a solid state reaction. Conductivity and interface behaviors on CGO/Pt and CGO/Ag were studied, respectively, by using ac impedance spectroscopy in the temperature range of 250℃ -600℃. And the relation of conductivity and temperature, interfacial resistance and temperature, frequency were studied .The diffusion mechanism of O2 on the electrode surface was also studied. It has been found that relationship of bulk conductivity, grain boundary conductivity and total conductivity with temperature all follow Arrhenius equation when electrode was Pt or Ag, the activation energy of conductance of CGO（Pt） was 0.41, 0.51, 0.42eV, respectively, and that That of CGO （Ag） was 0.43, 0.55, 0.42eV. The characteristic frequency of grain boundary impedance semicircle with temperature also follows Arrhenius laws. The interface impedance of Pt （Ag）/CGO mainly come from diffusion impedance of oxygen. The oxygen diffusion activationenergies of Pt/CGO and Ag/CGO are 0.32eV and 0.52eV, respectively