Effect of oxygen partial pressure on the electrochemical impedance of La_0.8Sr_0.2MnO_{3鈭?span style='font-style: italic'>未}/Zr_0.92Y_0.08O₂ porous composite anodes in solid oxide electrolysis

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• 作者：Jing Wang ; ^{wjing09@mails.tsinghua.edu.cn} ; ^{wangjing99@gmail.com} ; Yong Zhang ; Tongxiang Liang ; Changsheng Deng ; ^{changsheng@tsinghua.edu.cn} ; Jingming Xu
• 关键词：Solid oxide electrolysis cell ; Porous composite anode ; Oxygen partial pressure ; Impedance spectroscopy
• 刊名：Journal of Power Sources
• 出版年：2012
• 期刊代码：58_03787753
• 类别：ce
• 出版时间：15 June, 2012
• 卷：208
• 期：Complete
• 页码：415-420
• 文件大小：632 K

摘要

The electrochemical behavior of the La_0.8Sr_0.2MnO_3鈭?em>未/Zr_0.92Y_0.08O₂ (LSM/YSZ) porous composite anodes in solid oxide electrolysis cell is investigated by impedance spectroscopy over an oxygen partial pressure (pO₂) range from 0 to 0.6 脳 10⁵ Pa. The differential analysis of impedance spectra (DIS) shows three separate arcs which correspond to three different electrode processes at high, intermediate and low frequencies, respectively. Three different electrode processes can be attributed to the migration of oxygen ions from the electrolyte to the triple-phase boundary, concentration impedance associated with dissociative desorption of O^{2鈭?/sup> along the LSM surface and diffusion of oxygen, respectively. Interestingly, under low pO₂ (鈮? Pa), the impedance arcs become clearly separated at different frequencies, especially for the anodes with higher porosity. Meanwhile, the results demonstrate that the electrode process associated with the low-frequency arc is strongly affected by pO₂. Furthermore, the porosity plays an important role in dissociative adsorption and diffusion of oxygen.}