Properties of CuMn1.5Ni0.5O4 spinel as high-performance cathode for solid oxide fuel cells

Spinel oxide cathode has made great progress in solid oxide fuel cells (SOFCs) because of its special characteristics different from perovskite . In this study, a spinel-structured SOFC cathode, CuMn 1.5 Ni 0.5 O 4 (CMN), is proposed. Rietveld refinement shows that CMN takes the cubic structure of the space group of P4 3 32. CMN shows a high conductivity of about 70.0–91.2 S cm −1 at 600–800 ºC in the air and exhibits good catalytic activity for oxygen. A symmetric cell with CMN-GDC composite cathode demonstrates a low Rp of 0.047 Ω cm 2 at 800 ºC. The charge transfer of oxygen is the rate-limiting process at lower temperatures. The performance test results of the button cell with CMN-GDC composite cathode are excellent, with high power densities of 1342.4 mW cm −2 at 800 ºC. After a110h long-term test, the cell runs stably, and no microstructure damage is observed.