Impedance spectroscopic study on well-defined (La,Sr)(Co,Fe)O3-δ model electrodes
Impedance spectroscopic study on well-defined (La,Sr)(Co,Fe)O3-δ model electrodes
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DOI：
10.1016/j.ssi.2006.02.045
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发表时间：
2006-04-01
影响因子：
3.2
通讯作者：
Maier, Joachim
中科院分区：
文献类型：
--
作者：
Baumann, Frank S.;Fleig, Juergen;Maier, Joachim
采用脉冲激光沉积法和标准电沉积技术在氧化钇稳定的氧化锆基底上制备了混合导电固体氧化物燃料电池阴极材料La_（0.6）Sr_（0.4）Co_（0.8）Fe_（0.2）O_（3-δ）的几何形状良好的致密薄膜微电极。这些模型电极的电化学性能进行了研究，通过阻抗谱作为温度和直流偏压的函数。在参考文献[J. Jamnik和J. Maier，Phys.Chem.Chem.Phys.3，1668-1678（2001）]中严格推导出的具有混合导电电极的电池的等效电路为该实验系统提供了适当的描述，使得能够正确解释测量的阻抗数据。在零或小直流偏压下，电化学电阻由电极表面的氧交换反应主导，电极/电解质界面和电解质的欧姆电阻的贡献较小。主要的电容过程是与氧化学计量的变化在大部分的电极（化学电容），而额外的电极/电解质界面电容也存在。这些过程中的温度和直流偏置的依赖关系进行了讨论，在缺陷化学。(c)2006 Elsevier B. V.保留所有权利。
Geometrically well-defined, dense thin film microelectrodes of the mixed conducting solid oxide fuel cell cathode material La0.6Sr0.4Co0.8 Fe0.2O3-delta have been prepared by pulsed laser deposition and standard photolithographic techniques on yttria-stabilised zirconia substrates. The electrochemical properties of these model electrodes were investigated by impedance spectroscopy as a function of temperature and dc bias. It is shown that an equivalent circuit derived rigorously in Ref. [J. Jamnik and J. Maier, Phys. Chem. Chem. Phys. 3, 1668-1678 (2001)] for a cell with a mixed conducting electrode provides an appropriate description for this experimental system, enabling a correct interpretation of the measured impedance data. Under zero or small dc bias, the electrochemical resistance is dominated by the oxygen exchange reaction at the surface of the electrode, with minor contributions from the electrode/electrolyte interface and the ohmic resistance of the electrolyte. The main capacitive process is associated with oxygen stoichiometry changes in the bulk of the electrode (chemical capacitance), while an additional electrode/electrolyte interfacial capacitance is also present. The temperature and dc bias dependencies of these processes are discussed in terms of defect chemistry. (c) 2006 Elsevier B.V. All rights reserved.