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-& delta; (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 degrees C for 3 h results in homogeneous porous microstructure and good contact with the Sm0.2Ce0.8O1.95 (SDC) elec-trolyte. Among all the samples, the Sm0.5Sr0.5Co0.93Bi0.07O3-& delta; cathode shows the lowest polarization resistance (Rp) of 0.391, 0.209, 0.113 and 0.067 & omega; cm2 at 600, 650, 700 and 750 degrees C, respectively. The anode-supported single cell with Sm0.5Sr0.5Co0.93Bi0.07O3-& delta; nanofiber cathode shows a peak power density (PPDs) of 1.16 W cm-2 at 750 degrees C. These results suggest that nanofiber structure SSCB oxides are promising cathodes for SOFCs.