One-dimensional Sr0.7Y0.3CoO2.65−δ nanofibers as cathode material for IT-SOFCs

One dimensional (1-D) Sr0.7Y0.3CoO2.65−δ (SYCO) nanofibers and nanofiber-based Sr0.7Y0.3CoO2.65−δ-Gd0.2Ce0.8O1.9 (SYCO-GDC) composites have been prepared and studied as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). 1-D SYCO nanofibers are synthesized by electrospinning technique and the subsequent calcination processes. X-ray diffraction (XRD) results indicate that 900 °C is adequate for the formation of phase pure SYCO, much lower than the temperatures adopted in other reported methods for SYCO synthesis. 1-D nanofiber-based SYCO-GDC composite cathodes have been fabricated by infiltrating the ionic conducting GDC phase into the porous SYCO nanofiber scaffolds, achieving interfacial polarization resistances of 0.651, 0.200, 0.057 and 0.011 Ω cm2 at 600, 650, 700 and 750 °C, respectively, with an optimized SYCO:GDC mass ratio of 1:0.44. The stability of this SYCO-GDC (1:0.44) composite cathode was affirmed by 108-h constant current test. All these results suggest that 1-D nanofiber-based SYCO-GDC composite is a promising cathode material for IT-SOFCs.