Microstructure and electrical conductivity of La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _2.85 ‐Ce _0.8 Gd _0.2 O _1.9 composite electrolytes for SOFC s

Abstract (100‐ x ) wt.% La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _2.85 ‐ x wt.% Ce _0.8 Gd _0.2 O _1.9 ( 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 La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _2.85 electrolyte has a higher conductivity compared to the composite electrolytes, but at 650 ~ 800°C the 95 wt.% La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _2.85 ‐ 5 wt.% Ce _0.8 Gd _0.2 O _1.9 composite electrolyte presents the highest conductivity, reaching 0.035 S cm ⁻¹ at 800°C. The cell performances based on La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _2.85 ‐Ce _0.8 Gd _0.2 O _1.9 electrolytes were measured using Sr ₂ CoMoO ₆ ‐La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _2.85 as anode and Sr ₂ Co _0.9 Mn _0.1 NbO ₆ ‐La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _2.85 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.% La _0.9 Sr _0.1 Ga _0.8 Mg _0.2 O _2.85 ‐ 5 wt.% Ce _0.8 Gd _0.2 O _1.9 electrolyte reach 192 mW cm ⁻² and 720 mA cm ⁻² , respectively.