Research on the novel spinel structure of Cu0.5Ni0.5MnCoO4 and its application in solid oxide fuel cells

In this study, the Cu0.5Ni0.5MnCoO4 (CNMC) material was developed for use in the cathode of solid oxide fuel cells (SOFC). X-ray diffraction (XRD) confirmed the spinel structure and demonstrated compatibility with Yttriastabilized zirconia (YSZ) electrolyte at elevated temperatures. The conductivity of CNMC was found to be between 28 and 55 S cm-1 at temperatures ranging from 700 to 900 degrees C. Oxygen-temperature programmed desorption (O2-TPD) revealed that CNMC powder possesses effective oxygen catalytic characteristics. To enhance performance, CNMC was combined with Gd0.1Ce0.9O2-delta (GDC, H2-bank Co. Ltd.) in a mass ratio of 3:7 (CG37). The thermal expansion coefficient (TEC) of this composite was measured at 12.8 x 10-6 K-1, closely matching that of YSZ and avoiding the issue of strontium segregation, eliminating the need for a barrier layer between the electrolyte and the cathode. The peak power densities of CG37 reached 1175 mW cm-2 and 905 mW cm-2 at 800 degrees C and 750 degrees C, respectively. CG37 underwent testing for 1000 h under constant-current discharge at 600 mA cm-2 and 750 degrees C, showing a voltage degradation rate of 2.5 %/kh. The cell's microstructure remained intact without any signs of elemental diffusion or segregation, indicating excellent chemical compatibility and stable structural integrity. This research is expected to further advance the study and utilization of novel solid oxide fuel cells.