Electronic and crystal structure analyses of boron doped LiFeO2 cathode material by the XAFS spectroscopy

The influence of boron substitution in LiFeO2 (LFO) material on crystal and electronic structure properties has been investigated by x-ray absorption fine structure (XAFS) spectroscopy with the general formula "LiFe1−xBxO2" where x has values of 0.00, 0.05, and 0.10. The study revealed that boron has a key role in oxide materials due to its high effect on the oxygen regions and provides better performance values by reducing the excess oxygen in the material. The electronic structure properties were investigated by x-ray absorption near-edge spectroscopy (XANES). In this study, a new analysis method has also been applied for crystal properties determination like the Rietveld method for the first time and named “ Inverse EXAFS Fitting“. For the crystal structure study, extended XAFS (EXAFS) analyses were processed in reverse mode to determine the crystal lattice properties as an alternative way to the x-ray diffraction pattern (XRD) study and also to find out the atomic distances from the source Fe atoms. Due to the smaller ionic radii of B3+ cations than the Fe3+ cations, EXAFS data analysis has revealed that boron atoms did not sit in iron coordination, but formed the LiBO2 crystals and caused minor perturbations around iron atoms by loosening the Fe-O bonds. [Display omitted] •Influence of boron substitution on the atoms of LiFeO2 cathode materials were studied by XAFS calculations.•An inverse EXAFS fitting were applied to determine the crystal structure parameters.•k-weighting procedure were applied to find out the exact atomic distance of the boron atoms to iron and oxygen atoms successfully•Analysis revealed so much interesting data confirming the loose in the Fe-O bonding.•The results of the study show high agreement with the reports in the literature.