Novel high-entropy BaCo0.2Zn0.2Ga0.2Zr0.2Y0.2O3-δ cathode for proton ceramic fuel cells

The application of cobalt-based perovskite cathode materials in proton-conducting SOFCs (H-SOFCs) is challenged by their high thermal expansion coefficient (TEC). To address interface degradation/separation between the cobalt-based perovskite cathode and the proton-conducting electrolyte, we design and prepare the highentropy perovskite oxide (HEPO) BaCo0.2Zn0.2Ga0.2Zr0.2Y0.2O3-delta (BCX) as the cathode for proton-conducting SOFCs (H-SOFCs). BCX demonstrates remarkable performance and stability in the oxygen reduction reaction, validated through structural analysis and electrochemical characterizations. The TEC of BCX is as low as 12.75 x 10-6 K-1 compared to the 18.69 x 10-6 K-1 of the un-doped BaCoO3-delta (BC). The polarization resistance of BCX cathode about 0.69 omega cm2 is realized at 600 degrees C, much lower than that for pristine BC cathode (1.27 omega cm2). Cell with BCX cathode exhibits remarkable long-term stability without detectable degradation over 100 h.

Automated summary

In this study, we designed and prepared a high-entropy perovskite oxide (HEPO) BaCo0.2Zn0.2Ga0.2Zr0.2Y0.2O3-delta (BCX) as the cathode material for proton-conducting SOFCs (H-SOFCs), successfully addressing the interface degradation/separation issue between cobalt-based perovskite cathode and proton-conducting electrolyte. BCX cathode showed excellent oxygen reduction reaction performance and stability, with a low thermal expansion coefficient.