High-Performance Metal-Supported Protonic Ceramic Fuel Cell Utilizing Ammonia-Derived Fuel

Metal-supported protonic ceramic fuel cells (MS-PCFCs) are attractive for ammonia-based energy conversion, but their development is limited by coupled challenges associated with cosintering, fuel electrode reduction, and chemical stability under NH₃. In this work, these issues are examined using a Ni metal-supported PCFC as a representative system. By correlating reduction conditions and electrolyte processing, a fabrication window is identified that enables cosintering of a dense BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3-δ (BZCYYb1711) electrolyte with a porous Ni support while maintaining structural integrity. The incorporation of an anode functional layer improves interfacial compatibility and reduces ohmic resistance without disrupting electronic continuity. The interplay among electrolyte composition, sintering temperature, and Ni diffusion is further clarified, highlighting the trade-off between densification and protonic conductivity. For ammonia operation, an upstream NH₃ predecomposition strategy is employed to reduce chemical stress on the anode during long-term testing. Under these conditions, the MS-PCFC achieves peak power densities of 0.72 W cm^-2 with NH₃ and 1.05 W cm^-2 with H₂ at 700 °C and sustains stable operation for 300 h under NH₃ at 600 °C. The results provide practical insight into processing and microstructural considerations for Ni-based MS-PCFCs operated with ammonia.