Synthesis and characterization of Bi1-xSrxFeO3-δ(BSFO) nanofibers as cathodes for intermediate-temperature solid oxide fuel cells

Abstract Bi1-xSrxFeO3-δ (BSFO, x = 0, 0.1, 0.2, 0.3, 0.4) nanofibers were prepared by the electrospinning technology and evaluated as cathodes for intermediate temperature solid oxide fuel cells (IT-SOFCs). With the increase of Sr doping, the crystal structure changes from rhombohedral to cubic and the average diameter of the fibers decreased from 150 nm to 119 nm. When x = 0.3, BSFO nanofibers possess the lowest polarization resistance (0.137 Ω cm2 at 650 °C, 0.061 Ω cm2 at 700 °C), more than 75% smaller than that of BSFO nanopowders with the same composition (0.771 Ω cm2 at 650 °C, 0.282 Ω cm2 at 700 °C). The maximum power density of single cells with BSFO nanofiber cathode reaches up to 663.81 mW cm−2 at 700 °C using wet hydrogen (3 wt%) as fuels. The combination of element doping and microstructure optimizing is proven to be an effective approach for developing high-performance cathodes for IT-SOFCs.