Synthesis and characterization of La _0.9Sr _0.1Ga _0.8Mg _0.2O _3-δ intermediate-temperature electrolyte using conventional solid state reaction

The perovskite-type La _0.9Sr _0.1Ga _0.8Mg _0.2O _3-δ(LSGM9182) with high oxygen-ionic conductivity is successfully synthesized using conventional solid-state reaction. The phase composition, grain size distribution, relative density, and oxygen-ionic conductivity of the samples are studied. The XRD result shows that the main perovskite LaGaO ₃ phase can be produced at 1,250°C, with trace amount of second phase LaSrGaO ₄. When the temperature increases to 1,400°C, the pure phase LSGM can be obtained. The relative density of LSGM pellets sintered at 1,400°C reaches 98.08%. The average grain size of final powders is ∼0.12 μm, which is appropriate for the deposition of LSGM electrolyte film. The ideal oxygen-ionic conductivities of 0.04, 0.06, and 0.08 S cm ^-1 can be obtained at 700°C, 750°C, and 800°C, respectively. Porous anode supported single cells with LSGM electrolyte film are fabricated using the as-prepared LSGM powders and the cells provide an open-circuit voltage of above 1.0 V, revealing that the LSGM film is gas-tight and crack-free.