Enhanced electrochemical performance and operating stability of La0.8Sr0.2Co0.2Fe0.8O3-δ fiber cathode via Gd0.2Ce0.8O1.9-δ coating for intermediate temperature solid oxide fuel cells

Abstract

The low catalytic activity and poor long-term stability of cathode at intermediate temperatures are one of the bottlenecks hindering the application of solid oxide fuel cells. In this work, the highly active and robust La0.8Sr0.2Co0.2Fe0.8O3-δ (LSCF) nanofibers based composite cathodes with core-shell structure is prepared applying electrospinning combined with sol-gel method. Owing to the favorable oxygen ion transport capability of Gd0.2Ce0.8O1.9-δ (GDC) nanoparticle coating layer, the GDC coated LSCF nanorods composite cathode with GDC:LSCF mass ratio of 0.51:1 obtains the optimal electrochemical performance, reaching a polarization impedance of 0.03 Ω cm2 at 800 °C. Meanwhile, the composite cathode exhibits no obvious degradation for constant operating 200 h. Remarkably, XPS and Raman characterizations imply that the applying of GDC coating inhibits the formation of SrO and SrCrO4 during the long-term operating in Cr containing atmosphere, thereby endowing the higher long-term operation stability and Cr poisoning tolerance to LSCF based cathode.