High entropy engineering construction of high active and stable hybrid structure cathodes for advanced ceramic membrane fuel cells

For advanced ceramic membrane fuel cells, it is key to develop cathode with excellent oxygen reduction activity and superior operation stability. With unique structural features, adjustable elemental composition and tunable functional properties, high entropy materials have drawn a lot of interest in ceramic membrane fuel cells. In this work, the hybrid phase structure Pr0.5Ba0.5Fe0.2Co0.2Ni0.2Cu0.2Mn0.2O3-δ (HEPBM) cathode is designed by high entropy engineering and the structure, electrochemical performance and stability of the novel high entropy cathode are investigated detailed under operation atmosphere. As compared to the Pr0.5Ba0.5MnO3-δ (PBM) cathode (0.173 Ω·cm2), HEPBM cathode shows superior performance, reaching 0.084 Ω·cm2 at 850 °C. With better cathode activity, the single cell with HEPBM cathode exhibits the output power of 962.39 mW cm−2, which is higher than that of the cell with PBM cathode. In addition, no significant degradation of the cell could be observed under long-term testing at 0.7 V and 700 °C, suggesting excellent operation stability of the high entropy cathode. Our results suggest that high entropy engineering is an attractive strategy of constructing novel cathode materials, and HEPBM is one of the promising candidates for advanced ceramic membrane fuel cells.