BaZr(Ce,Y)O<sub>3</sub>‑Pr-Doped CeO<sub>2</sub> Double Columnar for the Cathodic\nFunctional Layer of Ni–Fe\nMetal-Supported Protonic Ceramic Fuel Cells

Metal-supported protonic ceramic fuel cells were prepared,\nand\nthe effects of a double columnar layer at the cathode side of BaZr<sub>0.44</sub>Ce<sub>0.36</sub>Y<sub>0.2</sub>O<sub>3</sub> (BZCY) on\npower density and open-circuit voltage (OCV) were studied. The double\ncolumnar structure of Pr<sub>0.2</sub>Ce<sub>0.8</sub>O<sub>2</sub> (PrDC) and BZCY was prepared with pulsed laser deposition. It was\nfound that the insertion of the double columnar layer was highly effective\nfor increasing the power density and OCV. The optimum composition\nof the double columnar was BZCY:PrDC = 7:3, with a thickness of 200\nnm. The power density of PCFCs with the BZCY-PrDC double columnar\nreached 413 mW/cm<sup>2</sup>, and the OCV was approximately 1.05\nV at 873 K, which is six times higher than that of a cell without\na functional layer. The high power density of the cell was attributed\nto the decreased overpotential of the cathode. Therefore, the BZCY-PrDC\ndouble columnar layer is effective in expanding the reaction site\nby increasing the proton concentration at the cathodic interface.