Effects of cathode materials on the characteristics of electrolyte supported micro-tubular solid oxide fuel cells

Abstract

The effects of the GDC-LSCF (Ce0.8Gd0.2O0-delta-La0.6Sr0.4Co0.2Fe0.8O3-delta) cathode layer and the GDC interlayer on the electrochemical performance of the ScSZ (Zr0.8Sc0.2O2-delta) electrolyte supported (approximate to 270 mu m) micro-tubular SOFC cells are investigated in this study. Material formulation and sintering profile for fabricating the micro-tubular SOFC cells are developed to avoid physical defects caused by the large sintering shrinkage mismatch among the layers. Cell B (with the LSCF-GDC composite cathode layer and the GDC interlayer) reports an ohmic resistance slightly higher than that of Cell A (with the GDC -La0.8Sr0 2MnO3-delta., i.e. LSM, composite cathode), while its polarization resistance emerges to be significantly smaller than that of Cell A. In terms of cell performance, Cell B demonstrates an OCV value (>1.07 V) similar to that of Cell A and a maximum power density (0.26W cm(-2)) 44.4% greater than that of Cell A (0.17 W cm(-2)) at 850 degrees C. It can thus be concluded that using the LSCF-GDC composite-cathode layer and inserting the GDC interlayer help reduce the total cell impedance, thereby improving the power density of the tubular cells. (C) 2013 Elsevier B.V. All rights reserved.