Ta-doped PrBaFe₂O_5+δ double perovskite as a high-performance electrode material for symmetrical solid oxide fuel cells

Symmetrical solid oxide fuel cells (S-SOFCs) have received considerable attention due to fewer preparation steps in recent years. The PrBaFe₂O_5+δ (PBF) is a candidate material due to good catalytic activity and electrochemical stability. In this work, Ta-substituted PBF materials (PrBaFe_2-xTa_xO_5+δ, denoted as PBFTx, x = 0, 0.1, 0.2, 0.3) are prepared and evaluated as symmetrical electrodes on GDC(Gd_0.1Ce_0.9O_2-δ)-YSZ(yttria-stabilized zirconia)-GDC three-layer electrolyte. The PrBaFe_1.8Ta_0.2O_5+δ (PBFT0.2) symmetrical cell presents the lowest polarization resistance, and the value is 0.171 Ω cm² and 0.503 Ω cm² in air and hydrogen atmosphere at 800 °C, respectively. In addition, the PBFT0.2 cell shows a peak power density of 234 mW/cm² using humidified hydrogen as fuel gas and air as oxidant at 800 °C, which is enhanced by 68% compared with that of PBF (138 mW/cm²). The results indicate that the strategy of Ta doping can improve the electrochemical performance of PBF and PBFT0.2 is a potential electrode for S-SOFCs.