Comparison of the electrochemical properties of impregnated and functionally gradient LaNi_0.6Fe_0.4O₃-Gd_0.2Ce_0.8O₂ composite cathodes for Solid Oxide Fuel Cell

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• 作者：Bo Huang^a ; ^{huangbo2k@hotmail.com} ; Xin-jian Zhu^a ; Huai-wen Nie^b ; Ya-ran Niu^b ; Yang Li^a ; Nian Cheng^a
• 关键词：Cathode ; Electrochemical properties ; Functionally gradient cathode ; Impregnation ; Impedance spectroscopy ; Solid Oxide Fuel Cell
• 刊名：Journal of Power Sources
• 出版年：2013
• 出版时间：1 August, 2013
• 年：2013
• 卷：235
• 期：Complete
• 页码：20-28
• 全文大小：947 K

文摘

This study investigates the electrochemical properties of three different configurations of LaNi_0.6Fe_0.4O₃ (LNF)-based cathodes for Solid Oxide Fuel Cell (SOFC). The results show functionally gradient LNF cathode and Gd_0.2Ce_0.8O₂ (GDC)-impregnated LNF cathode both reveal the better electrochemical properties compared to that of 70?wt. % LNF-30?wt. % GDC cathode. Functionally gradient LNF cathode with better interface of LNF/GDC/ScSZ can be achieved by the gradual change in composition from electrolyte to cathode, resulting in the decline in charge transfer resistance and gas phase diffusion resistance, therefore the decline in specific cathode polarization resistance (R_p). Whereas, the dramatic decrease in R_p for GDC-impregnated LNF cathode is mainly attributed to the extended triple phase boundary (TPB) and enhanced oxide ion conductivity. The nano-sized GDC particle on LNF backbone with high porosity would allow gas phase molecules to easily diffuse to the LNF/GDC/ScSZ boundaries, which significantly enhances cathode activities for oxygen reduction reaction (ORR). The GDC-impregnated LNF cathode reveals the lowest R_p, the lowest activation energies of R_p and the lowest activation energy of ORR among three cathode configurations. Noticeably, the cathode performance can be significantly improved by impregnating nano-sized GDC particles into LNF porous backbone.