Performance of La-doped strontium titanate (LST) anode on LaGaO 3-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 LaGaO 3-based electrolyte. A La-doped SrTiO 3 (LST, La 0.2Sr 0.8TiO 3) is a candidate as an anode material to solve the Ni poisoning problem in LaGaO 3-based SOFC. In this study, a single-phase LST and an LST-Gd 0.2Ce 0.8O 2 − δ (GDC) composite were tested as the possible anodes on La 0.9Sr 0.1Ga 0.8Mg 0.2O 3 − δ (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 °C to 800 °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 R p value was further reduced to ~ 10% of the single-phase LST anode, and it was 1 Ωcm 2 at 800 °C in 97% H 2 + 3% H 2O atmosphere. A single cell with Ni-impregnated LST-GDC as an anode, Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3 − δ (BSCF) as a cathode and LSGM as an electrolyte exhibited the maximum power density of 275 mW/cm 2 at 800 °C, increased from ~ 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.