Chemical synthesis and properties of La1.9Ba0.1Mo1.9Mn0.1O9 as electrolyte for IT-SOFCs

The highly phase-pure electrolyte materials with composition La1.9Ba0.1Mo1.9Mn0.1O9 (LBMMO) was prepared by the sol-gel auto-combustion method for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The details of gelʹs auto-combustion, phase evolution, sintering, thermal expansion and electrochemical performance of LBMMO were investigated by means of thermo-gravimetry (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron spectroscopy (TEM), thermal expansion curve (TEC) and complex impedance spectra. The results showed that the highly phase-pure electrolyte LBMMO could be obtained after calcining at 600 °C. The sample sintered at 900 °C for 4 h in air exhibited a better sinterability, and the relative density of LBMMO was higher than 96%. The electrical conductivities of the sample were 6.7×10−3 and 25.9×10−3 S/cm at 700 and 800 °C in air, respectively. Results also showed that LBMMO had moderate thermal expansion (α=16.3×10−6 K−1, between room temperature and 800 °C) and an electrical activation energy equal to 1.32 eV).