Electrode properties of (Pr0.9La0.1)2−x(Ni0.74Cu0.21Al0.05)O4+δ (with x=0, 0.05, and 0.1) as cathodes in IT-SOFCs

• Published in: Journal of alloys and compounds 2019-07, Vol.793, p.519-525
• Main Authors: Mao, Jialun, Peng, Shuting, Zhang, Chao, Qi, Siming, Cui, Jinghao, Gong, Yuhan, Wang, Shaoshuai, Wu, Chongrui, Zhou, Qingjun
• Format: Article
• Language: English
• Subjects: A-site deficiency; Cathodes; Cobalt-free cathode; Electrical resistivity; Electrochemical analysis; Electrode materials; Electrolytes; Electrolytic cells; K2NiF4-type oxide; Maximum power density; Organic chemistry; Solid oxide fuel cells; Thermal expansion; Thermal stability
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.04.078

A Ruddlesden-Popper phase, (Pr0.9La0.1)2−x(Ni0.74Cu0.21Al0.05)O4+δ ((PL)2−xNCA, x = 0, 0.05 and 0.1), is synthesized and characterized for use as a cathode material in intermediate temperature solid oxide fuel cells (IT-SOFCs). The effects of A-site cation deficiency on the thermal expansion coefficient, electrical conductivity, electrochemical properties, and thermal stability are investigated in detail. (PL)2−xNCA and the Ce0.8Sm0.2O1.9 (SDC) electrolyte are chemically compatible at 1000 °C for 5 h. The average thermal expansion coefficient (TEC) values of (PL)2−xNCA range from 14.1 × 10−6 K−1 to 14.5 × 10−6 K−1 for temperatures between 30 and 1000 °C, which is close to that of conventional SOFC electrolyte materials. The (PL)2−xNCA samples were unstable after heating to 700 and 800 °C for 72 h in air. The (PL)1.9NCA cathode had a minimum area specific resistance (ASR) of 0.033 Ω cm2 at 800 °C. When (PL)2.0NCA was used as the cathode material in electrolyte-supported single cells, the single cell reached a maximum power density of 527 mW cm−2 at 800 °C using an SDC electrolyte. •The system (Pr0.9La0.1)2−x(Ni0.74Cu0.21Al0.05)O4+δ ((PL)2−xNCA) evaluated as candidate cathode materials for IT-SOFCs.•(PL)2−xNCA has a good chemical compatibility with SDC electrolyte.•The TECs of (PL)2−xNCA was much lower than cobalt-based cathodes.•Low ASR of 0.033 Ω cm2 was obtained with (PL)1.9 NCA at 800 °C.•(PL)2−xNCA suffers from phase decomposition at high temperatures.