In a direct ammonia proton ceramic fuel cell (DA-PCFC), attaching a catalyst layer on the surface of the ammonia electrode is known to optimize the cell's electrochemical performance and long-term stability. In this study, the Fe catalyst layer is added to the ammonia electrode of the full cell which is prepared with the structure Ni– BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ (BZCYYb) (support layer)|Ni-BZCYYb (active layer)|BZCYYb|La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ to investigate its impact on the electrochemical performance and stability of the electrode. Under the conditions of 700 °C and 20 ml min −1 ammonia fuel, the peak power densities of cells with and without the Fe layer reach 585.051 and 463.671 mW cm −2 , respectively. It is evident that the addition of the Fe catalytic layer significantly improves the electrochemical performance of the cell. Stability tests are carried out for cells with and without the Fe layer at 650 °C, 0.36 A cm −2 , and 0.32 A cm −2 constant current discharge. After discharge for 313 and 372 h, both cells show good stability, and the discharge curves of the two cells are consistent after 100 h. The high M − N binding energy of the Fe catalytic layer improved the initial performance of the cell, but this improvement is not sustained over the stability.
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.