Models of lithium transport as applied to determination of diffusion characteristics of intercalation electrodes

Abstract

In order to elucidate the mechanism of lithium transport in intercalation electrodes based on solid lithium-accumulating compounds and determine its parameters, the kinetic models are used which allow the combined analysis of electrode impedance spectroscopy, cyclic voltammetry, pulse chronoampero- and chronopotentiometry data to be carried out. The models describe the stages of consecutive lithium transport in the surface layer and bulk of electrode-material particles, including the accumulation of species in the bulk. The lithium transport stages that occur in the surface layer of an intercalation-material particle and in its bulk are both of the diffusion nature but substantially differ as regards their characteristic times and diffusion coefficients D. Taking account of this peculiarity and assessing adequately the geometrical configuration of intercalation system allow the diffusion parameters of lithium transport to be correctly determined.