Behavior of strontium- and magnesium-doped gallate electrolyte in direct carbon solid oxide fuel cells

• La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) can be used as electrolyte of direct carbon SOFCs.
• DC-SOFC with LSGM electrolyte gives higher performance than that with YSZ.
• LSGM-electrolyte DC-SOFC gives maximum power density of 383 mW cm−2 at 850 °C.
• Operation of LSGM-DC-SOFC at 210 mA cm−2 lasts 72 min, with fuel utilization of 60%.

Perovskite-type La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM) is synthesized by conventional solid state reaction. Its phase composition, microstructure, relative density, and oxygen-ionic conductivity are investigated. Tubular electrolyte-supported solid oxide fuel cells (SOFCs) are prepared with the LSGM as electrolyte and gadolinia doped ceria (GDC) mixed with silver as anode. The SOFCs are operated with Fe-loaded activated carbon as fuel and ambient air as oxidant. A typical single cell gives a maximum power density of 383 mW cm−2 at 850 °C, which is nearly 1.3 times higher than that of the similar cell with YSZ as electrolyte. A stability test of 72 min is carried out at a constant current density of 210 mA cm−2, with a fuel utilization of 60%, indicating that LaGaO3-based electrolyte is promising to be applied in direct carbon SOFCs (DC-SOFCs).