Performance of La-doped strontium titanate (LST) anode on LaGaO3-based SOFC

Abstract

Ni-containing anode is currently used with many electrolytes of solid oxide fuel cells (SOFCs). However, Ni is easily oxidized and deteriorates the LaGaO3-based electrolyte. A La-doped SrTiO3 (LST, La0.2Sr0.8TiO3) is a candidate as an anode material to solve the Ni poisoning problem in LaGaO3-based SOFC. In this study, a single-phase LST and an LST-Gd0.2Ce0.8O2-delta (CDC) composite were tested as the possible anodes on La0.9Sr0.1Ga0.8Mg0.2O3-delta (LSGM) electrolyte. In order to further improve the anodic performance, Ni was impregnated into the LST-GDC composite anode. The performance was examined from 600 degrees C to 800 degrees C by measuring impedance of the electrolyte-supported, symmetric (anode/electrolyte/anode) cells. A polarization resistance (R-p) of LST-GDC anode was much reduced from that of LST anode. When Ni was impregnated into LST-GDC composite, the Rp value was further reduced to similar to 10% of the single-phase LST anode, and it was 1 Omega cm(2) at 800 degrees C in 97% H-2 + 3% H2O atmosphere. A single cell with Ni-impregnated LST-GDC as an anode, Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) as a cathode and LSGM as an electrolyte exhibited the maximum power density of 275 mW/cm(2) at 800 degrees C, increased from similar to 60 mW/cm(2) for the cell using the LST-GDC as an anode. Thus, LST-GDC composite is promising as a component of anode. (C) 2009 Elsevier B.V. All rights reserved.