Electrical properties of La0.85Sr0.15Ga0.8Mg0.2O3−δ samples prepared by one- or three-stage solid-state calcination process

Abstract

La0.85Sr0.15Ga0.8Mg0.2O3−δ (LSGM1520) samples are prepared by one- or three-stage solid-state calcination process. The influence of calcination and sintering parameters on the densification, grain size, phase structure, conductivity, and activation energy of LSGM1520 electrolyte samples are investigated and the most suitable process method is identified. The results show that the three-stage calcination procedure is effective in preparing higher purity LSGM1520 powders than those obtained with the traditional one-stage calcination procedure. Conductivities of the A2 and C4 electrolyte samples at 800 °C are 0.18 and 0.17 S cm−1, respectively. The A2 and C4 of LSGM1520 electrolyte samples are from the one-stage and three-stage calcination procedures, respectively. The open-circuit voltage and maximum power density values of cells prepared using A2 and C4 as electrolytes at 800 °C are 1.01 V and 370 mW cm−2, and 0.97 V and 367 mW cm−2, respectively. Hence, the A2 electrolyte sample, prepared though a simpler process than the C4 electrolyte, displays good cell performance. Although the A2 sample contains a very small amount of secondary phase, its conductivity and cell performance are not significantly reduced at temperatures above 700 °C, as expected.