Microstructure and electrical conductivity of La0.9Sr0.1 Ga0.8Mg0.2O2.85‐Ce0.8Gd0.2O1.9 composite electrolytes for SOFCs.

(100‐x) wt.% La0.9Sr0.1 Ga0.8Mg0.2O2.85 ‐ x wt.% Ce0.8Gd0.2O1.9 (x = 0, 5, 10, 20) electrolytes were prepared by solid‐state reaction. The composition, microstructure, and electrical conductivity of the samples were investigated. At 300 ~ 600°C, the pure La0.9Sr0.1 Ga0.8Mg0.2O2.85 electrolyte has a higher conductivity compared to the composite electrolytes, but at 650 ~ 800°C the 95 wt.% La0.9Sr0.1 Ga0.8Mg0.2O2.85 ‐ 5 wt.% Ce0.8Gd0.2O1.9 composite electrolyte presents the highest conductivity, reaching 0.035 S cm−1 at 800°C. The cell performances based on La0.9Sr0.1 Ga0.8Mg0.2O2.85‐Ce0.8Gd0.2O1.9 electrolytes were measured using Sr2CoMoO6‐La0.9Sr0.1 Ga0.8Mg0.2O2.85 as anode and Sr2Co0.9Mn0.1NbO6 ‐La0.9Sr0.1 Ga0.8Mg0.2O2.85 as cathode, respectively. At 800°C, the measured open‐circuit voltages are higher than 1.08 V, and the maximum power density and current density of the fuel cell prepared with 95 wt.% La0.9Sr0.1 Ga0.8Mg0.2O2.85 ‐ 5 wt.% Ce0.8Gd0.2O1.9 electrolyte reach 192 mW cm−2 and 720 mA cm−2, respectively. [ABSTRACT FROM AUTHOR]