On the influence of ion interactions on the predictions of a non-interacting model applied to evaluate lithium-ion battery materials

Abstract

In this work, we evaluate the reliability of a recently developed model for estimating kinetic parameters for different materials used in lithium-ion batteries. This model considers non-interacting Li-ions being inserted under constant current conditions, assuming finite diffusion inside the particles and charge transfer limitations at the electrode/electrolyte interface. Here, we are interested in evaluating the effect of neglecting the particular insertion isotherms of the materials on the fittings made for diffusion coefficients and electrochemical rate constants. With this purpose, equilibrium isotherms of different materials are extracted from an open-access Li-ion battery parameter database. This thermodynamic information is introduced into the model to perform simulations and obtain the maximum state of charge reached as a function of C-rate. This data is then fitted to the model without interactions using our open-source Python package. The fitted values obtained for the diffusion coefficients are finally compared with the reference values from the database to estimate the accuracy of the model for different real-world systems.