Effect of optimal GDC loading on long-term stability of La0.8Sr0.2Co0.2Fe0.8O3-δ/Gd0.2Ce0.8O1.9 composite cathodes

Three types of La0.8Sr0.2Co0.2Fe0.8O3-delta/Gd0.2Ce0.8O1.9 (LSCF/GDC) composite cathodes with different optimal GDC loading are fabricated through electrospinning, screen printing and solution infiltration method. Constant current polarization with current density of 100 mA cm(-2) at 750 degrees C is applied to test the stability of LSCF/GDC composite cathodes. After constant current polarization for 144 h, the polarization resistance (R-p) of 280 nm-nanofiber skeletal LSCF/GDC composite cathode after pore-forming exhibits the minimum increase, from 0.062 Omega cm(2) to 0.098 Omega cm(2). Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) results show that the microstructure and surface chemical composition of the cathode maintain stable during the constant current polarization. Combined with the X-ray diffraction (XRD) result, a relationship among GDC loading, stress, Sr surface segregation and long-term stability is established.