The influence of the Li addition rate during the hydrothermal synthesis of LiFePO on the average and local structure.

A hydrothermal method was used to synthesize LiFePO to explore the effect of the rate of addition of the Li precursor to a mixture of the Fe and PO precursors. Both the average and local structures were investigated using powder X-ray diffraction, Mössbauer spectroscopy and X-ray absorption spectroscopy. Slower addition rates led to increased oxidation of Fe to Fe despite purging all solutions constantly, as well as increased defects. The local structure as determined by extended X-ray absorption fine structure displayed far less variation between the samples. The formation of a LiPO impurity appeared to be independent of the Li addition rate.