# Electrochemical Nucleation and Growth in Battery Electrodes under Reactant-Limited Conditions

## TL;DR

This paper presents a new model for understanding how solid phases form in batteries, improving predictions of performance under limited reactant conditions.

## Contribution

A novel nucleation–growth model that accounts for finite reactant supply and asymmetric growth in battery electrodes.

## Key findings

- The model accurately reproduces current transients during nucleation without ad hoc corrections.
- Application to Li2S nucleation yields high nucleus densities and a measurable reaction rate constant.
- The framework is applicable to various battery chemistries with finite-supply effects.

## Abstract

Nucleation and growth
of solid phases from species dissolved
in
an electrolyte govern battery performance, defining capacity, efficiency,
rate capability, stability, and safety. However, classical nucleation–growth
models often do not realistically describe working cells, failing
to capture highly asymmetric out-of-plane growth and finite reactant
supply. Here, we introduce a nucleation–growth model to fit
potentiostatic nucleation transients that explicitly accounts for
a finite amount of reactant and its depletion, reproducing the characteristic
current rise upon nucleation, peak, and subsequent decay without ad
hoc corrections. Both instantaneous nucleation and progressive nucleation
are considered. The model is applied to the nucleation and growth
of Li2S at a catalyzed electrode from a lithium polysulfide
solution, yielding nucleus densities of up to 6.7 × 109 cm–2 and an effective reaction rate constant of
1.8 × 10–3 s–1. Beyond Li–S
batteries, the framework can be extended to other conversion and metal-deposition
chemistries in which finite-supply effects dominate.