Investigation of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3- δ Electrode Performance and Microstructural Evolutions Based on Three Dimensional Microstructure Reconstruction and Electrochemical Simulation

The influence of initial microstructure of gadolinium-doped-ceria (GDC) interlayer on La0.6Sr0.4Co0.2Fe0.8O3-d (LSCF) performance evolution was studied. The cell with the GDC interlayer fired at 1300 ˚C (GDC1300), in which SrZrO3 phase shows discontinuous formation between GDC interlayer and yttria-stabilized-zirconia (YSZ) electrolyte, showed gradual increase of polarization resistance during 100 hours operation. In contrast, when the GDC interlayer was fired at 1200 ˚C (GDC1200), continuous SrZrO3 layer was formed between interlayer electrolyte interface, and the cell showed large polarization resistance with recovery during operation. The Strontium oxide phase was formed inside the LSCF cathode phase after the operation of GDC1300 at 800 ˚C, whereas the GDC1300 operated at 700 ˚C and GDC1200 operated at either 700 ˚C or 800 ˚C showed no decomposition of LSCF phase. It is considered that the differences of performance and microstructural evolution are highly dependent on initial microstructures and operating temperatures.