Enhanced electrochemical performance of (PrBa)_xFe_1.9Nb_0.1O_5+δ symmetrical electrodes with A-site deficient for symmetrical solid oxide fuel cells

Symmetrical solid oxide fuel cells (SSOFCs) with symmetrical electrodes have many desirable characteristics compared with conventional SOFCs. However, the lack of electrode materials simultaneously satisfied the high electrocatalytic activity in oxidizing and reducing atmospheres. Herein, a novel perovskite oxide electrode (PrBa)_xFe_1.9Nb_0.1O_5+δ ((PB)xFN, x = 1, 0.97, 0.95 and 0.93) was reported as a promising symmetrical electrode material for SSOFCs. XRD results reveal that the (PB)0.95FN sample has a tetragonal structure and good chemical compatibility with Gd_0.1Ce_0.9O_2-δ electrolyte. Among all the samples, (PB)0.95FN has the lowest polarization resistance (Rp). At 800 °C, compared with primary PBFN, the cathode Rp of (PB)0.95FN is reduced from 0.109 Ω cm² to 0.063 Ω cm² in air, whereas the anode Rp is decreased from 0.3808 Ω cm² to 0.3109 Ω cm² in H₂. In addition, an electrolyte-supported single cell with ( PB)0.95FN symmetrical electrodes achieves a maximum peak power density at 800 °C, which is enhanced by 14.67 % compared with that of PBFN. A-site deficiency on PBFN perovskite shows better electrochemical performance, which is attributed to an increase in oxygen vacancy concentration. The results indicate that (PB)0.95FN is a potential electrode material for SSOFCs.