Evaluating the impact of transport inertia on the electrochemical response of lithium ion battery single particle models

Abstract

The description of the transport mechanisms in operating Li ion battery cells is of key importance for a correct evaluation of their performance and for their optimization.In this work, we revise the Fickian approach for the description of the lithium transport in intercalation-type active materials. We adopt the Maxwell-Cattaneo-Vernotte (MCV) theory to capture the impact of lithium transport inertia on the electrochemical response of graphitic materials, taken here as an application example. We formalize this theory by means of an analytical mathematical expression which allows extracting the values of the lithium diffusion coefficient DMCV and the inertia characteristic time τ from potentiostatic intermittent titration technique (PITT) experiments. The implications of adopting the MCV theory in single particle models to calculate transient current response during the graphite lithiation are discussed (i) on the basis of the fitting of the calculations with in house PITT results and, (ii) by comparing the estimated diffusion coefficients with the ones resulting from the fitting using the classical Fickian approach.