Determination of the crystal structure and charge density of (Ba0.5Sr0.5)(Co0.8Fe0.2)O2.33 by Rietveld refinement and maximum entropy method analysis

The crystal structure and charge density of (Ba0.5Sr0.5)(Co0.8Fe0.2)O2.33, a promising cathode material for solid oxide fuel cells with lower operating temperatures, were investigated by the Rietveld refinement method and the maximum entropy method (MEM) using neutron and synchrotron X-ray diffraction data. The crystal structure of (Ba0.5Sr0.5)(Co0.8Fe0.2)O2.33 was refined by using the orthorhombic Pnma space group and the split atom model to cation sites. The occupancy of O1 ( 4 c ) and O2 ( 8 d ) sites are 0.59 and 0.87, respectively. From the MEM analysis, we found that (Ba0.5Sr0.5)(Co0.8Fe0.2)O2.33 possessed both covalent and ionic bonds.