AC Impedance Spectra Arising from Mixed Ionic Electronic Solid Electrolytes
AC Impedance Spectra Arising from Mixed Ionic Electronic Solid Electrolytes
复制标题
混合离子电子固体电解质产生的交流阻抗谱
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
N. Brandon
中科院分区：
文献类型：
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作者：
A. Atkinson;S. Baron;N. Brandon
由 Pt/Ce 0.9 Gd 0.1 O 1.95-δ /Pt 组成的对称电池的交流阻抗谱已在空气中和不同还原气氛下在 250-650°C 的温度范围内测量。还原条件下的电极响应显示出对非常低频率的贡献，因此具有大的表观电容。这是由电解质中的化学扩散引起的，电解质在还原条件下变成混合离子电子导体。使用 Jamnik 和 Maier 开发的理论以及电解质的非化学计量、化学扩散以及离子和电子电导率的文献数据对光谱进行定量解释。结果表明，如果使用纯离子电解质的传统等效电路而不是适当的分析，则可能会在还原条件下得出有关电极电化学性能（低电荷转移电阻、高电容和气体传输限制）的误导性结论。结果还描述了为了从阻抗谱中提取有关电极的有用信息而必须满足的条件。
AC impedance spectra of symmetrical cells consisting of Pt/Ce 0.9 Gd 0.1 O 1.95-δ /Pt have been measured in air and under different reducing atmospheres at temperatures in the range 250-650°C. The electrode response under reducing conditions shows a contribution extending to very low frequencies and thus a large apparent capacitance. This is caused by chemical diffusion in the electrolyte, which becomes a mixed ionic-electronic conductor under reducing conditions. The spectra are interpreted quantitatively using a theory developed by Jamnik and Maier and literature data for the nonstoichiometry, chemical diffusion, and ionic and electronic conductivity of the electrolyte. The results show that misleading conclusions can be drawn concerning the electrochemical properties of the electrodes (low charge-transfer resistance, high capacitance and gas-transport limitations) under reducing conditions if the conventional equivalent circuit for a purely ionic electrolyte is used instead of the proper analysis. The results also delineate the conditions that must he satisfied in order for useful information about the electrode to be extracted from the impedance spectrum.