Theoretical approach of the lithium intercalation/deintercalation process in host materials

A new theoretical approach of the intercalation/deintercalation process of lithium cations into host materials is proposed in that paper taking into a ccount the dependence of the lithium diffusion coefficient on concentration is considered for the integration of the mass balance equation. Numerical simulation of chronopotentiograms is used to solve the diffusion equation. The component and chemical diffusion coefficients corresponding to the Liintercalation into Nb2O5 in 1 M LiClO4-PC were determined. It was found tha t (D) over tilde (Li) and D-Li decrease from 1.4 x 10(-11) cm(2) s(-1) to 5 .7 x 10(-11) cm s(-1) and from 1.2 x 10(-11) cm(2) s(-1) to 6.4 x 10(-13) c m(2) s(-1), respectively, with increasing values of the intercalation ratio , y, comprised between 0.4 and 1.6. Impedance measurements performed in an equilibrium situation give (D) over tilde (Li) and D-Li values which were r ather constant but higher.