Boosting the electrochemical performance of Bi-doped Sm0.5Sr0.5Co1-xBixO3-δ perovskite nanofiber cathodes for solid oxide fuel cells

In this study, Sm0.5Sr0.5Co1-xBixO3-δ (SSCB, x = 0.00–0.10) nanofiber cathode materials were prepared by electrospinning for solid oxide fuel cells (SOFCs). X-ray diffraction (XRD) results show that all SSCB nanofibers present orthorhombic perovskite structures. X-ray photoelectron spectroscopy (XPS) analysis indicates that the Sm3+, Sr2+, Co3+/Co4+, and Bi3+ species exist in the SSCB samples. The SSCB nanofiber cathode heated at 900 °C for 3 h results in homogeneous porous microstructure and good contact with the Sm0.2Ce0.8O1.95 (SDC) electrolyte. Among all the samples, the Sm0.5Sr0.5Co0.93Bi0.07O3-δ cathode shows the lowest polarization resistance (Rp) of 0.391, 0.209, 0.113 and 0.067 Ω cm2 at 600, 650, 700 and 750 °C, respectively. The anode-supported single cell with Sm0.5Sr0.5Co0.93Bi0.07O3-δ nanofiber cathode shows a peak power density (PPDs) of 1.16 W cm−2 at 750 °C. These results suggest that nanofiber structure SSCB oxides are promising cathodes for SOFCs.