Sequential symmetry breakings in charging and discharging Li batteries

TL;DR

This paper models and predicts the sequential symmetry breaking phenomena in lithium batteries during charging and discharging, highlighting the effects of initial conditions and noise on phase separation behavior.

Contribution

It introduces a quantitative model for symmetry breaking in Li batteries, incorporating phase separation thermodynamics and noise effects, validated by simulations and experiments.

Findings

Sequential symmetry breaking characterized by Li concentration and phase fraction.

Initial separation and noise significantly influence SB characteristics.

A bifurcation map delineates conditions for homogeneous lithiation/delithiation.

Abstract

The sequential group-by-group charging/discharging in Li batteries with phase-separation thermodynamics was detected by numerical simulations and justified by several experiments published in literature. The present work is the first to quantitatively predict the main characteristics of the sequential symmetry breaking (SB) such as the average Li concentration and the fraction of the low Li part at the SB points. Using a reduced two-zone (low and high concentration) model we derived an approximate solution predicting the effect of initial separation or of imposed parameter perturbation referred to as 'noise' on the SB characteristics. We suggest that the governing parameters that account for the complex effect are the liquid potential drop over the cathode and the noise factor. A bifurcation map showing the lowest current boundary that ensures a homogeneous lithiation/ delithiation as the function of noise is constructed