Kinetics of lithium electrodeposition and stripping

TL;DR

This paper applies Marcus-Hush-Chidsey kinetics to lithium electrodeposition and stripping, demonstrating its importance for accurately modeling fast charge/discharge processes in lithium batteries used in electric vehicles and aircraft.

Contribution

It introduces the use of MHC kinetics in lithium electrode modeling, compares it with other models, and provides an open-source implementation within Cantera.

Findings

MHC kinetics accurately predict Tafel data for lithium electrodes.

Significant deviations in overpotentials are observed between different kinetic models at high rates.

Open-source implementation of MHC kinetics in Cantera is provided.

Abstract

Electrodeposition and stripping are fundamental electrochemical processes for metals and have gained importance in rechargeable Li-ion batteries due to lithium metal electrodes. The electrode kinetics associated with lithium metal electrodeposition and stripping is crucial in determining performance at fast discharge and charge which is important for electric vertical take-off and landing (eVTOL) aircraft and electric vehicles (EV). In this work, we show the use of Marcus-Hush-Chidsey (MHC) kinetics to accurately predict the Tafel curve data from the work of Boyle et al. We discuss the differences in predictions of reorganization energies from the Marcus-Hush and the MHC models for lithium metal electrodes in four solvents. The MHC kinetic model is implemented and open-sourced within Cantera. Using the reaction kinetic model in a pseudo-2D battery model with a lithium anode paired with a LiFePO$_4$ cathode, we show the importance of accounting for the MHC kinetics and compare it to the use of Butler-Volmer (BV) and Marcus-Hush kinetic models. We find that significant deviation in the overpotentials associated with reaction kinetics for the two different rate laws for conditions of fast discharge and charge relevant for eVTOL and EV respectively.