Fabrication of LSCF and LSCF-GDC nanocomposite thin films using polymeric precursors

Abstract

La 1- x Sr x Co y Fe 1- y O 3 (LSCF) and LSCF-gadolinia-doped ceria (LSCF-GDC) composites are used as solid oxide fuel cell (SOFC) cathodes. In the present study, to maximize the LSCF/gas and LSCF/GDC interfacial area and thus enhance the performance, we fabricated both single-phase LSCF and composite LSCF-GDC thin-film electrodes using a facile and cost-effective polymeric precursor technique. This method involves molecular level mixing of cations in solution form and results in average particle sizes of ca. 72 nm and 60 nm upon annealing at 700 °C, respectively. For LSCF, electrochemical impedance spectroscopy measurements indicate very low electrode polarization resistances of ca. 0.6 Ω cm 2 per electrode at 600 °C. However, the addition of GDC results in poorer electrochemical activity but better microstructural and electrochemical stability, all at 600 °C. Surface analysis revealed that Fe surface segregation occurs in the single-phase LSCF, while predominantly Co segregation is observed at the LSCF-GDC composite electrode surface.