The Li insertion in the ordered olivine-type structure of LiFePO4 was analyzed as an insertion process with a Frumkin-type sorption isotherm. A minimum in the chemical diffusion coefficient of Li (DLi) was predicted by the model for strong attractive interactions between the intercalation species and the host matrix. The DLi in the material was measured as a function of the Li content by using the galvanostatic intermittent titration technique. The diffusion coefficient was found 1.8 x 10-14 and 2.2 x 10-16cm2/s for LiFePO4 and FePO4, respectively, with a minimum in correspondence of the peak of the differential capacity. The DLi had also been measured by alternating-current impedance method for various Li contents. The calculated values were in very good agreement with the previous calculated ones.

Determination of the Chemical Diffusion Coefficient of Lithium in LiFePO4. P.P.Prosini, M.Lisi, D.Zane, M.Pasquali: Solid State Ionics, 2002, 148[1-2], 45-51