Multi-physics simulations of lithiation-induced stress in Li$_{\rm 1+x}$Ti$_2$O$_4$ electrode particles

TL;DR

This paper presents a multi-physics, multi-scale modeling approach combining first principles calculations and continuum modeling to study stress evolution and crack potential in Li$_{1+x}$Ti$_2$O$_4$ electrode particles during lithiation and delithiation.

Contribution

It introduces a novel integrated framework that combines density functional theory, statistical mechanics, and phase field modeling to analyze lithiation-induced stress in electrode materials.

Findings

Stress localization can lead to crack initiation during lithiation/delithiation.

Heterogeneous nucleation affects stress distribution and evolution.

The model predicts maximum principal stress evolution under different conditions.

Abstract

Cubic spinel Li$_{\rm 1+x}$Ti$_2$O$_4$ is a promising electrode material as it exhibits a high lithium diffusivity and undergoes minimal changes in lattice parameters during lithiation and delithiation, thereby ensuring favorable cycleability. The present work is a multi-physics and multi-scale study of Li$_{\rm 1+x}$Ti$_2$O$_4$ that combines first principles computations of thermodynamic and kinetic properties with continuum scale modeling of lithiation-delithiation kinetics. Density functional theory calculations and statistical mechanics methods are used to calculate lattice parameters, elastic coefficients, thermodynamic potentials, migration barriers and Li diffusion coefficients. These quantities then inform a phase field framework to model the coupled chemo-mechanical evolution of electrode particles. Several case studies accounting for either homogeneous or heterogeneous nucleation are considered to explore the temporal evolution of maximum principle stress values, which serve to indicate stress localization and the potential for crack initiation, during lithiation and delithiation.