Physical properties of (SrBa)1-xPrx(CuTi)0.2Fe0.8O3-δ (x = 0–1.0) and its application in H-SOFCs

Abstract A series of mixed ionic-electronic conductors (SrBa)1-xPrx(CuTi)0.2Fe0.8O3-δ ((SB)1-xPxCTF, x = 0–1.0, with interval of 0.2) are synthesized. A single cubic perovskite structure is obtained for x = 0–0.8 while secondary phases are observed for x = 1. With increasing Pr content, the electrical conductivity of dense (SB)1-xPxCTF increases significantly while the thermal expansion coefficient decreases continuously from 29.6 × 10−6 K−1 for x = 0 to 11.6 × 10−6 K−1 for x = 0.8. Good chemical compatibility is observed between (SB)1-xPxCTF and BaZr0.1Ce0.7Y0.2O3-δ (BZCY) or Ce0.8Sm0.2O2-δ (SDC). Among all single cells with NiO-BZCY|BZCY|(SB)1-xPxCTF-SDC configuration, the best comprehensive electrochemical performance is obtained for x = 0.4. The maximum power density of single cells is 925 ± 38 mW·cm−2 at 750 °C. The corresponding polarization resistance is only 0.07 Ω·cm2. With the help of electrochemical impedance spectra of both single cells and symmetrical cells, the effects of Pr content on the electrochemical properties are discussed.