# The effect of mechanical stress on lithium distribution and geometry optimisation for multi-material lithium-ion anodes

## TL;DR

This paper presents a coupled mechanical-chemical model for lithium-ion anodes with multi-material structures, revealing how stress influences lithium distribution and voltage, and enabling optimization of anode design.

## Contribution

It introduces a stress-dependent chemical potential model for multi-material anodes and demonstrates optimization of silicon core volume considering stress effects.

## Key findings

- Stress significantly affects lithium distribution and OCV in multi-material anodes.
- The model enables optimization of silicon core volume to improve anode performance.
- Stress-coupling impacts lithium intercalation and maximum stress in the anode.

## Abstract

A model is presented for predicting the open-circuit voltage (OCV) and lithium distribution within lithium-ion anodes containing multiple materials, coupling linear elasticity with a stress-dependent chemical potential. The model is applied to a spherical radially-symmetric nano-particle with a silicon core and a graphite shell, highlighting the large effect on lithium distribution and OCV caused by the stress-coupling. Various performance measures based on the expanded volume, the amount of lithium intercalated and the maximum stress induced, are calculated for a silicon core with a graphite shell to enable optimisation of the volume of the silicon core.