Structural, Thermal, and Electrical Study of Bi0.5Sr0.5MnO3

Abstract

Solid oxide fuel cell (SOFC) is considered as a potential candidate for clean and efficient alternate energy source. Efforts are being made to reduce their operating temperature for SOFCs commercialization. However, the reduction in operating temperature increases the polarization effect in the existing cathodes. In the present study, Bi0.5Sr0.5MnO3 was synthesized and studied for its structural, thermal, and electrical properties. Bi0.5Sr0.5MnO3 was synthesized by conventional solid state reaction method. The as-prepared sample was characterized by x-ray diffraction, scanning electron microscope, thermogravimetric analysis, dilatometer and impedance spectroscopy. The Rietveld refinement results confirm that Bi0.50Sr0.50MnO3 shows the tetragonal symmetry with p4 mm space group. Scanning electron microscopy study shows that the distribution of grains is uniform and the grains are well connected to each other due to better sinterability of the samples. The dilatometric curve shows linear behavior up to 600°C and after that becomes steeper. This can be due to the loss of lattice oxygen at higher temperatures and creation of oxygen vacancies. The thermal expansion coefficient of the system is ∼8.9 × 10−6 °C−1 and total conductivity of the sample is ∼4.78 × 10−3 S/cm.