Ionic Conductivity of Chemically Synthesized La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3-δ) Solid Electrolyte

摘要

Strontium and magnesium-doped lanthanum gallate is a solid electrolyte with higher ionic conductivity than yttria-stabilized zirconia. This perovskite-type ionic conductor has been investigated for application as solid electrolyte in intermediate-temperature solid oxide fuel cells. In this work the La_(0.9)Sr_(0.1)Ga_(0.8)Mg_(0.2)O_(3-δ) composition was synthesized by a soft chemistry route seeking for a more homogeneous microstructure. Densification was carried out by the conventional method and by fast firing. The ionic conductivity of sintered specimens were evaluated by impedance spectroscopy. The apparent density was about 90% and 94% for fast fired and conventionally sintered specimens, respectively. No significant difference was found for the grain conductivity of specimens fast fired at 1500 °C for 5 min and sintered by the conventional method at 1450 °C for 4 h.