Study of the efficiency of composite LaNi0.6Fe0.4O3-based cathodes in intermediate-temperature anode-supported SOFCs

The paper focuses on the performance comparison of LaNi_0.6Fe_0.4O_3-δ (LNF) composite cathodes comprising Ce_0.8Sm_0.2O_1.9 (SDC) and Bi_1.5Y_0.5O₃ (YDB) electrolytes and La_0.6Sr_0.4Fe_0.8Co_0.2O_3-δ (LSFC)-SDC cathodes in anode-supported SOFCs with YSZ/GDC electrolyte films obtained by magnetron sputtering. Cathodes with LNF-SDC and LNF-YDB functional layers and the LNF-YDB-CuO oxide collector show a sufficient thermo-mechanical compatibility with the electrolyte. The performance of the anode-supported SOFC with the LNF-YDB/LNF-YDB-CuO cathode, reaches 650 and 1050 mW/cm² at 700 and 800 °C, respectively, which is significantly higher than that obtained in other works for anode-supported cells with LNF cathodes. The initial total polarization resistance of the NiO-YSZ/YSZ/GDC/LNF-YDB/LNF-YDB-CuO cell, is 0.53 Ω cm², which is lower than the initial resistance of the similar anode-supported cell with the LNF-SDC/LNF-YDB-CuO cathode (1.35 Ω cm²) and LSFC-SDC cathode with LNF-YDB-CuO (1.71 Ω cm²) and La_0.6Sr_0.4CoO₃ (1.17 Ω cm²) collectors. The most probable reason for the LNF-YDB electrode aging is the growth of Bi-containing particles. Experimental results show that LNF-based composite cathodes are competitive with cobalt-containing cathodes and can be promising for anode-supported SOFCs with decreased operating temperature, that allows extending the material choice for both functional and collector cathode layers.