Observation of dendrite formation at Li metal-electrolyte interface: A machine-learning enhanced constant potential framework

TL;DR

This paper introduces a machine-learning enhanced constant potential framework for simulating dendrite formation at Li metal-electrolyte interfaces, providing atomic-level insights and a new modeling approach for electrochemical interfaces.

Contribution

It presents a novel constant potential simulation method combining machine learning force fields and charge equilibration, enabling realistic modeling of dendrite nucleation processes.

Findings

Inhomogeneous Li depositions can initiate dendrites.

The new method accurately captures electrochemical depositions.

Insights into Li dendrite formation mechanisms.

Abstract

Uncontrollable dendrites growth during electrochemical cycles leads to low Coulombic efficiency and critical safety issues in Li metal batteries. Hence, a comprehensive understanding of the dendrite formation mechanism is essential for further enhancing the performance of Li metal batteries. Machine learning accelerated molecular dynamics (MD) simulations can provide atomic-scale resolution for various key processes at an ab-initio level accuracy. However, traditional MD simulation tools hardly capture Li electrochemical depositions, due to lack of an electrochemical constant potential (ConstP) condition. In this work, we propose a ConstP approach that combines a machine learning force field with the charge equilibration method to reveal the dynamic process of dendrites nucleation at Li metal anode surfaces. Our simulations show that inhomogeneous Li depositions, following Li aggregations in amorphous inorganic components of solid electrolyte interphases, can initiate dendrites nucleation. Our study provides microscopic insights for Li dendrites formations in Li metal anodes. More importantly, we present an efficient and accurate simulation method for modeling realistic ConstP conditions, which holds considerable potential for broader applications in modeling complex electrochemical interfaces.