Ba and Gd doping effect in (Ba xSr 1-x) 0.95Gd 0.05Co 0.8Fe 0.2O 3-δ (x=0.1-0.9) cathode on the phase structure and electrochemical performance

In this study, BaxSr1xCo0.8Fe0.2O3 delta (BSCF) doped with trace of Gd were studied for phase structures and properties about thermal expansion, electrical conductivity, and electrocatalytic activity. The solution range of barium in BaxSr1xCo0.8Fe0.2O3 delta can be extended to 0.1 <= x <=?0.7 after the introduction of small amount of Gd3+ ions (only for 5%) into the Ba/Sr-site. The calculation results of the crystal structure and the crystal lattice energy show that the ratio of Ba/Sr and doping of Gd3+ lead to increase the lattice parameter and the Co/Fe ionic average valence state in B-site. Moreover, the ratio of Ba/Sr and doping of Gd3+ were found to have significant impacts on the high-temperature physical properties and electrochemical characteristics. All oxides exhibited decreases in the thermal expansion coefficient (TEC) and electrical conductivity with increasing Ba/Sr ratio. Barium insertion was found to change the area-specific resistance (ASR) of porous (not dense) cathodes. An ASR values of 0.048, 0.072, 0.064, 0.121, and 0.059 Omega cm2 under air condition were observed at 650?degrees C for BSGCF with x?=?0.1, 0.2, 0.3, 0.5, and 0.7, respectively.