Synthesis and characterization of apatite-type La9.67Si6-xAlxO26.5-x/2 electrolyte materials and compatible cathode materials

Apatite silicates have recently been reported as promising electrolyte materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). In this work, a series of apatite-type compounds La9.67Si6-xAlxO26.5-x/2 (LSAO) with x = 0–2 are synthesized by the sol–gel process at calcining temperature of 800–900 °C. Thermal expansion coefficient, relative density and electrical conductivity of these samples with different Al doped contents are investigated. A symmetrical cell, which is composed of La9.67Si5AlO26 electrolyte and (La0.74Bi0.10Sr0.16)MnO3+δ (LBSM) cathode, is fabricated and electrochemically characterized. LBSM cathode shows a good electrochemical performance, which proves LBSM to be a promising candidate cathode for LSAO-based electrolyte.

► The series of apatite-phase compounds La9.67Si6-xAlxO26.5-x/2 were synthesized. ► The properties of these samples with different Al doped contents were investigated. ► Symmetrical cells with (La0.74Bi0.10Sr0.16)MnO3+ä (LBSM) cathode were fabricated. ► LBSM was found to be a promising candidate cathode for LSAO-base electrolyte.