Effects of Ti doping on the electrochemical performance of (La0.75Sr0.25)(Mn0.5Cr0.5)O3-δ anode for solid oxide fuel cells

Abstract

Single phase La0.75Sr0.25Mn0.5Cr0.5-xTixO3-?(LSCMT, 0 ? x ? 0.3) perovskites were investigated as possible anode material for solid oxide fuel cells with yttria stabilized zirconia (YSZ) electrolyte. LSCMT samples were synthesized by solid state reaction method and sintered at 1500?C in air. Rietveld refinement of X-ray powder diffraction data show that the LSCMT materials crystallize in the rhombohedral symmetry with R?3C space group. The cell parameters of the sample with 10 at.% of Ti (x = 0.1) were: a = b = 5.5125(4)?; c = 13.3397(6)?; ? = 90?; ? = 90?; ? = 120?. The scanning electronmicroscopy analyses confirmed the presence of sufficient porosity (about 35%). Symmetrical LSCMT|YSZ|LSCMT cell configurations with different Ti-doping (x = 0.1, 0.2 and 0.3) and good interface without delamination between the two materials, even after reduction process, were also prepared. Ti doping was very effective in reducing the interfacial polarization resistance with the lowest value of 0.22W?cm2 and conductivity of 0.23 S/cm in 5% H2/Ar at 800 ?C. The obtained results suggest that Ti doping can substantially improve electrochemical performance of (La0.75Sr0.25)(Mn0.5Cr0.5)O3-? ceramics.