Characterization and optimization of Ln_1.7Sr_0.3CuO₄ (Ln = La, Nd)-based cathodes for intermediate temperature solid oxide fuel cells

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• 作者：Xifeng Ding ; Xin Kong ; Xiong Wang ; Jinguo Jiang ; Chong Cui
• 关键词：SOFC ; Cathode ; Ln₂CuO₄ ; Electrochemical performance
• 刊名：Journal of Alloys and Compounds
• 出版年：2010
• 出版时间：23 July 2010
• 年：2010
• 卷：502
• 期：2
• 页码：472-476
• 全文大小：652 K

文摘

The Ln_1.7Sr_0.3CuO₄ (Ln = Nd, La), i.e., NSCu and LSCu materials with perovskite-related structure were synthesized and evaluated as new cathodes for intermediate temperature solid oxide fuel cells (IT-SOFCs). The crystal structure, thermal expansion, electrical conductivity and electrochemical performance of Ln_1.7Sr_0.3CuO₄ cathodes have been investigated by X-ray diffraction, dilatometry, DC four-probe method, AC impedance and cyclic voltammetry (CV) techniques. The conductivity of NSCu and LSCu reached 106 S cm⁻¹ and 125 S cm⁻¹ at 800 °C. NSCu cathode exhibited much lower area specific resistances (ASR) than LSCu, e.g., the ASR values for NSCu cathode on Sm-doped ceria (SDC) electrolyte in air were 0.07 Ω cm², 0.09 Ω cm² and 0.24 Ω cm² at 800 °C, 750 °C and 700 °C, while the corresponding values for LSCu were 0.11 Ω cm², 0.21 Ω cm² and 0.44 Ω cm², respectively. To further optimize the electrochemical performance of the cathodes, a certain amount of Sm-doped ceria (SDC) electrolyte was introduced. The polarization resistance of NSCu–SDC30 and LSCu–SDC30 was 0.12 Ω cm² and 0.18 Ω cm² at 700 °C in air, nearly half of pure NSCu and LSCu, respectively.