A New Pd Doped Proton Conducting Perovskite Oxide with Multiple Functionalities for Efficient and Stable Power Generation from Ammonia at Reduced Temperatures

The combination of ammonia fuel and proton-conducting fuel cells (PCFCs) technology may provide an ideal clean energy system for the future, considering matured NH₃ synthesis technology and transportation and storage infrastructure, the high energy density of NH₃, and the high efficiency of fuel cells. However, poor catalytic activity of the anode for NH₃ decomposition, quick performance degradation due to the ammonia induced nickel coarsening, difficult sintering, and insufficient proton conductivity of electrolytes are the main challenges for stable and high-power generation from ammonia-fueled PCFCs. Herein, a new Ba(Zr_0.1Ce_0.7Y_0.1Yb_0.1)_0.95Pd_0.05O_3−δ perovskite is reported as a key anode component and electrolyte, which demonstrates multifunctionalities and tackles most challenges of conventional PCFCs. The incorporation of a small amount of Pd boosts catalytic activity of the nickel-perovskite cermet anode for NH₃ decomposition and increases proton conductivity from the creation of B-site cation deficiency and electrolyte sintering. The corresponding thin-film electrolyte PCFC delivers a maximum power density of 724 mW cm^–2 at 650 °C operated on NH₃, much higher than the similar cell without Pd incorporation (450 mW cm^–2). Furthermore, no apparent performance decay is observed for the cell operated at 550 °C in H₂ and NH₃ for 350 h, making it highly promising for practical applications.