Effect of metal ion concentration on synthesis and properties of La0.84Sr0.16MnO3 cathode material

A reactive powder of La0.84Sr0.16MnO3 is synthesized as a cathode material for solid oxide fuel cells by a citrate-nitrate auto-ignition process and characterized by thermal analysis, X-ray diffraction and electrical conductivity measurements. The effect of starting metal ion concentration in the precursor solution on the properties of the final oxide is studied and correlated through particle size analyses, sintering studies and microstructural examination. Sintered La0.84Sr0.16MnO3 ceramics of relative density around 93% can be fabricated by preferably keeping the metal ion concentration in the precursor to less than 0.8M, whereas to make porous ceramics (relative densities of 75-80%) a higher metal ion concentration is preferred. At 1000 deg C, the 93% dense ceramics exhibit electrical conductivities of around 168-169Scm-1 and the porous ceramics of around 136-146Scm-1.