A novel cobalt-free double perovskite PrBaFe2O6-δ cathode for direct ammonia proton ceramic fuel cells

Direct ammonia proton ceramic fuel cells (DA-PCFCs) have garnered significant attention in the clean energy sector as a promising technology for achieving carbon-free and efficient energy conversion. The cathode material, as a key component of this system, possesses intrinsic properties that significantly impact the overall performance of the DA-PCFCs. To address the characteristics of ammonia fuel systems, this study synthesized a novel cobalt-free double perovskite cathode material, PrBaFe 2 O 6-δ (PBF), via the sol-gel method. Systematic characterization revealed that PBF not only exhibited a stable cubic perovskite structure, but also synergistically enhanced the oxygen reduction reaction through the combination of mixed Fe ion valence states and abundant surface oxygen vacancies. Furthermore, the thermal expansion coefficient of PBF exhibited better compatibility with the electrolyte than cobalt-containing cathodes. These properties provided a robust foundation for the favorable performance of DA-PCFCs. Electrochemical tests demonstrated that the cell with the PBF cathode achieved a peak power density of 379 mW·cm −2 at 700 °C, with a 67.4 % power retention rate under H 2 fuel conditions. Notably, the performance degradation rate of the cell was only 0.06 % h −1 after 100 h of constant current discharge, indicating excellent operational stability. This study presented an effective strategy to the development of cathodes for DA-PCFCs.