Nanofiber-structured SSC–GDC composite cathodes for a LSGM electrolyte based IT-SOFCs

Nanofiber-structured Sm0.5Sr0.5CoO3−δ–Gd0.2Ce0.8O1.9 (SSC–GDC) composite cathodes prepared by infiltration of Gd0.2Ce0.8O1.9 (GDC) precursor solution into a porous Sm0.5Sr0.5CoO3−δ (SSC) nanofiber scaffold are investigated. The SSC–GDC composite cathode with the optimum infiltration load of GDC achieves interfacial polarization resistances of 1.609, 0.595, 0.209, 0.081 and 0.038 Ω cm2 at 600, 650, 700, 750 and 800 °C, respectively. These polarization resistances are lower than those reported for comparable materials. Stable performance of the cathode is confirmed by testing at a constant current of 0.2 A/cm2 for up to 100 h. Furthermore, the peak power density of a cell using the nanofiber-structured SSC–GDC cathode in combination with a 650-μm-thick La0.8Sr0.2Ga0.8Mg0.2O3−δ electrolyte is found to be 0.134 W/cm2 at 800 °C. All of these results make of the nanofiber-structured SSC−GDC composite cathodes a potential high-performance component for use in intermediate temperature solid oxide fuel cells.