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.
To optimize the oxygen reduction reaction activity and long-term stability of the PrBaFe2O6-δ(PBF) cathode for protonic ceramic fuel cell (PCFC), this study employed the sol–gel method to dope Sc at the Fe-site of PBF, preparing a novel PrBaFe1.8Sc0.2O6-δ(PBFS) cathode. The effects of different sintering temperatures on the phase composition, microstructure, and electrochemical performance of the PBFS cathode were systematically studied. Results showed that the PBFS cathode sintered at 1000 °C formed a single cubic perovskite structure, exhibiting excellent chemical compatibility with the electrolyte. Sc doping induced Fe in the cathode to exhibit a mixed valence state of Fe2+/Fe3+/Fe4+, thus significantly increasing the oxygen vacancy concentration. The single cell assembled achieved a peak power density of 1.303 W·cm−2and a polarization resistance as low as 0.035 Ω·cm2with H2as the fuel at 700 °C. Moreover, after 100 h of long-term operation at 650 °C, the power density decayed by only 5.23%, thus demonstrating excellent long-term stability. This study offers an efficient cobalt-free cathode candidate for PCFC.
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