Chemical synthesis and properties of La1.9Ba0.1MO1.9Mn0.1O9 as electrolyte for IT-SOFCs

The highly phase-pure electrolyte materials with compositionLa1.9Ba0.1MO1.9Mn0.1O9（LBMMO） was prepared by the sol-gel auto-combustion method for intermediate-temperature solid oxide fuel cells （IT-SOFCs）. The details ofgel＇s auto-combustion, phase evolution, sintering, thermal expansion and electrochemical performance of LBMMO were investigated by means of thermo-gravimetry （TG）, X-ray diffxaction （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 ℃. The sample sintered at 900 ℃ 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 6.7x 10-3 and 25.9× 10-3 S/cm at 700 and 800 ℃ in air, respectively. Results also showed that LBMMO had moderate thermal expansion （a=16.3×10-6 K-l, between room temperature and 800 ℃） and an electrical activation energy equal to 1.32 eV）.