Structural, Thermal, Electrical and Dielectric Properties of La1-xSrxMn0.50Fe0.50O3 {0.10 ≤ x ≤ 0.40} Cathode Material for Solid Oxide Fuel Cells

Abstract

La1-xSrxMn0.50Fe0.50O3 {0.10 ≤ x ≤ 0.40} perovskite ceramics material is prepared by solid-state reaction method and samples are characterized to study their structural, thermal, electrical and dielectric properties. X-ray diffraction results show that as prepared samples are well crystallized in single phase and have rhombohedral crystal structure. Density is measured by Archimedes principle and with Sr substitution its value decreasing. Thermogravimetric analysis shows the weight gain in the material above 300 ºC. Thermal expansion coefficient value for x = 0.10 and 0.40 composition is found to be 12.9 × 10-6 ºC−1 and 11.3 × 10-6 ºC−1, respectively upto 800 ºC. Impedance analyzer is used to study dielectric and electrical properties which show that all the as prepared samples obey non-Debye relaxation behaviour. The maximum conductivity value is 121.09 S cm-1 for x = 0.10 and 155.96 S cm-1 for x = 0.40 at 600 ºC and 303.59 S cm-1 for x = 0.10 and 362.35 S cm-1 for x = 0.40 at 800 ºC which confirmed that in the experimental perovskite the conductivity increases after Sr doping. Activation energy also found to be decreases with Sr substitution. Therefore, studied properties confirmed that the as-prepared material is a suitable cathode material for intermediate temperature solid oxide fuel cells (SOFCs).