Influence of the synthesis method on the porosity, microstructure and electrical properties of La0.7Sr0.3MnO3 cathode materials

Lanthanum strontium manganite (La1 − xSrxMnO3, LSM) has been studied as a promising material for application as a cathode in solid oxide fuel cells. In the present work La0.7Sr0.3MnO3 nanopowders were synthesized by three different methods (combustion, citrate and solid-state) and characterized by thermal analysis, X-ray diffraction, physical adsorption of N2 and scanning electron microscopy. All powders exhibited single LSM phase formation with crystallite sizes in the range of 12–20 nm. Nanopowders were sintered at 1100 °C to produce porous pellets. The porosity, particle size and microstructure of LSM sintered bodies are strongly dependent on the preparation methodology. The samples synthesized by combustion and citrate methods presented smaller particle sizes and higher porosity after sintering than that derived from solid-state synthesis. However, the electrical conductivity, measured by two-probe technique, was very similar for all three samples.