Interaction of La0.8Sr0.2MnO3 interlayer with Gd0.1Ce0.9O1.95 electrolyte membrane and Ba0.5Sr0.5Co0.8Fe0.2O3−δ cathode in low-temperature solid oxide fuel cells

Low-temperature solid oxide fuel cells with a La0.8Sr0.2MnO3 (LSM) interlayer between the Ce0.9Gd0.1O1.95 (GDC) electrolyte membrane (20 μm) and the Ba0.5Sr0.5Co0.8Fe0.2O3 (BSCF)–GDC composite cathode are fabricated by sintering the BSCF–GDC composite cathodes at 900, 950 and 1000 °C. The results of scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) for a model LSM/BSCF bi-layer pellet suggest that Ba, Co and Fe in BSCF as well as La and Mn in LSM have diffused into their counter sides. The X-ray diffraction (XRD) results on the simulated cells also indicate the incorporation of La into the GDC electrolyte membrane and the mutual diffusion of elements between the LSM layer and the BSCF layer. Analysis of the impedance spectra and interfacial reaction activation energies shows that LSM interlayer accelerates the oxygen reduction. Considering a good cell performance and the highest open-circuit voltages (OCVs) at 600–500 °C, the optimum sintering temperature of BSCF–GDC composite cathode onto LSM interlayer is 900 °C.