EXAFS analysis of LiFePO4 and Li4Ti5O12 samples produced via chemical technique

EXAFS (extended X-ray absorption fine structure) spectra of two triphylite (lithium iron phosphate) samples and a lithium titanate (lithium titanium oxide) sample have been measured and processed. A new method of EXAFS data analysis including a procedure to separate spectrum oscillations based on the variation principle and estimating Fourier window limits has been applied to all the spectra. The volume fractions of impurity phases in the samples are estimated. An assumption is made that the titanate sample contains about 40 vol% titanium oxide in the anatase phase. It is shown that triphylite sample #1 may contain about 1% maghemite (magnetic phase of iron-III oxide) and triphylite sample #2 may include 5–10% iron-III phosphate.