Electrical behavior of the Ruddlesden–Popper phase, (Nd0.9La0.1)2 Ni0.75Cu0.25O4 (NLNC) and NLNC- x wt% Sm0.2Ce0.8O1.9 (SDC) (x = 10, 30 and 50), as intermediate‐temperature solid oxide fuel cells cathode

Abstract

In the present work, a new Ruddlesden-Popper phase, (Nd0.9La0.1)2 Ni0.75Cu0.25O4 (NLNC) has been synthesized by solid state reaction for intermediate-temperature solid oxide fuel cells (IT-SOFCs) applications. The effect of sintering temperature on the microstructure and electrical properties of the NLNC cathode material is investigated. Likewise, composite cathode materials were also prepared by mixing the NLNC with 10, 30 and 50wt% of Sm0.2Ce0.8O1.9 (SDC) powders, and firing in the temperature range of 1000–1300°C. The crystal structure and chemical compatibility of NLNC and SDC, and their microstructures were studied by XRD and SEM, respectively. Electrical conductivity and performance of monolithic and composite electrodes as a function of the electrode composition is investigated experimentally through four probe method and electrochemical impedance spectroscopy (EIS). The results proved that no reaction occur between NLNC and SDC compounds even at a temperature as high as 1300°C. Maximum total electrical conductivity of 114.36Scm−1 at 500°C is recorded for the pure NLNC material sintered at 1300°C. The polarization resistance of pure NLNC cathode was 0.43Ωcm2 at 800°C; the NLNC–SDC composite cathodes including 10, 30 and 50wt% SDC displayed Rp value of 0.27Ωcm2, 0.11Ωcm2, and 0.19Ωcm2 at 800°C, respectively.