BaZr(Ce,Y)O₃-Pr-Doped CeO₂ Double Columnar for the Cathodic Functional Layer of Ni–Fe Metal-Supported Protonic Ceramic Fuel Cells

Metal-supported protonic ceramic fuel cells were prepared, and the effects of a double columnar layer at the cathode side of BaZr0.44Ce0.36Y0.2O3 (BZCY) on power density and open-circuit voltage (OCV) were studied. The double columnar structure of Pr0.2Ce0.8O2 (PrDC) and BZCY was prepared with pulsed laser deposition. It was found that the insertion of the double columnar layer was highly effective for increasing the power density and OCV. The optimum composition of the double columnar was BZCY:PrDC = 7:3, with a thickness of 200 nm. The power density of PCFCs with the BZCY-PrDC double columnar reached 413 mW/cm2, and the OCV was approximately 1.05 V at 873 K, which is six times higher than that of a cell without a functional layer. The high power density of the cell was attributed to the decreased overpotential of the cathode. Therefore, the BZCY-PrDC double columnar layer is effective in expanding the reaction site by increasing the proton concentration at the cathodic interface.