Fe K-Edge X-ray absorption near-edge spectroscopy (XANES) and X-ray diffraction (XRD) analyses of LiFePO₄ and its base materials

XANES analysis has been performed with the aim of knowing the Fe oxidation state in a synthesized LiFePO₄ and its base materials. XANES measurements were performed at SLRI on energy around Fe K-edge. An XRD analysis has also been performed with the aim of knowing the phase composition, lattice parameters and crystallite size of the LiFePO₄ as well as the base materials. From the XRD analysis, it was found that the dominating phase in the iron sand sample was Fe₃O₄ and the only phase found after calcination was LiFePO₄. The latter phase exhibited crystallite size of 100 nm and lattice parameters a = 10.169916 Å, b = 5.919674 Å, c = 4.627893 Å. Qualitative analysis of XANES data revealed that the oxidation number of Fe in the sample before calcination was greater than that after calcination and Fe in the natural iron sand, indicated by the E₀ values of 7129.2 eV, 7120.6 eV and 7124.4 eV respectively. (paper)