Preparation and characterization of La0.9Sr0.1Ga0.8Mg0.2O2.85–(Li/Na)2CO3 composite electrolytes

Lowering operating temperature is the main direction of solid oxide fuel cells (SOFCs). Exploitation of new electrolytes with excellent performance is urgently required to develop low-temperature SOFCs, operating at 300–600 °C. A series of composite materials consisting of La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) and a binary eutectic carbonates (52 mol% Li2CO3:48 mol% Na2CO3) were investigated with respect to their structure, morphology and ionic conductivity. The structure study showed only LSGM phase could be found in the composites. The morphology study showed the composition could prevent LSGM particles from agglomeration, forming a homogenous composite. The conductivity was measured in air, nitrogen and hydrogen, respectively. The composite electrolytes showed much higher conductivity than the pure LSGM at evaluated temperatures, 0.122 S cm−1 at 600 °C in air. A sharp conductivity jump appeared at 450 °C for composite electrolytes with various carbonate contents in air. The conductivity study showed different transition temperature but comparable conductivities in different atmosphere.