Friday, 28 July 2017: 09:00
Atlantic Ballroom 1/2 (The Diplomat Beach Resort)
The influence of initial microstructure of gadolinium-doped-ceria (GDC) interlayer on La0.6Sr0.4Co0.2Fe0.8O3-d (LSCF) performance was studied with three dimensional microstructure reconstruction by focused ion beam – scanning electron microscopy (FIB-SEM). When the GDC interlayer was fired at 1300 ˚C (GDC1300), discontinuous SrZrO3 phase was formed between GDC interlayer and yttria-stabilized-zirconia (YSZ) electrolyte. In addition, inter-diffused layer of GDC and YSZ was formed at the neighbor of the SrZrO3 phase and along the YSZ electrolyte interface. When the GDC interlayer was fired at 1200 ˚C (GDC1200), continuous SrZrO3 layer was formed. Inter-diffused layer was formed along the YSZ electrolyte. Both cells were operated at 700 ˚C and 800 ˚C . The initial electrode resistance of GDC1200 was more than 20 times larger than that of GDC1300. Slight increase of electrode resistance was found for GDC1300 after the cell operation, whereas the drastic activation was found for GDC1200. The activation was enhanced at operating temperature of 700 ˚C than 800 ˚C . For GDC1300, Sr rich phase was formed after the operation at 800 ˚C. It is considered that the differences of performance and microstructural evolution are highly dependent on initial microstructures and operating temperatures. The different electrode performances are evaluated based on electrochemical simulation using reconstructed microstructures.