Co-free and Sr-free double-perovskite oxide PrBaFeNbO as a potential electrode material for symmetrical solid oxide fuel cells

Double-perovskite oxide PrBaFeO (PBF) is considered as a potential electrode material because of its superior oxygen reduction reaction (ORR) activity in air and excellent stability in wet hydrogen atmospheres. However, the electrochemical activities of Fe-based electrode materials are constrained by the oxygen vacancy concentration and oxy-ion transport properties. Herein, PrBaFeNbO (PBFNx, x = 0, 0.05, 0.1, 0.15) oxides are synthesized and evaluated as electrodes for symmetrical solid oxide fuel cell (SSOFC). X-ray diffraction (XRD) indicates that PBFNx samples have an orthorhombic structure and good chemical compatibility with electrolyte. Among all the samples, the PBFN0.1 symmetrical half-cell shows the lowest polarization resistance at 800 °C, which decreases by 29.2% compared with that of PBF in air and decreases by 59.9% compared with that of PBF in wet hydrogen atmospheres. The output performance of the single cell with PBFN0.1 as symmetrical electrodes achieves 197.10 mW cm in wet hydrogen atmospheres at 800 °C, which is an improvement of 31.97% compared with that of PBF. The enhanced electrochemical performance can be attributed to an increase in oxygen vacancy concentrations. The results suggest that the PBFN0.1 material is a potential candidate for SSOFC.