Characterization of sol-gel-synthesized LiFePO4 by multiple scattering XAFS

X-ray absorption spectroscopy (XAS) was used to investigate the local structure arrangements of submicrocrystalline lithium iron phosphate and its precursors. The former material, proven to be very promising as active cathode material in lithium metal and lithium-ion batteries, was synthesized through a new procedure that combines a simple sol-gel precipitation with a moderate temperature (e.g., low cost) heat treatment. X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra taken at the Fe K-edge pointed out the modification of the Fe site during the synthesis steps that allow one to produce the submicrometer size crystalline LiFePO4 (active material) useful for batteries applications. The XAS investigation has shown that such a material is different from the conventional crystalline LiFePO4 on the short-range order. The difference is attributed to the synthesis procedure.