Issue 8, 2024

Replica exchange molecular dynamics for Li-intercalation in graphite: a new solution for an old problem

Abstract

Li intercalation and graphite stacking have been extensively studied because of the importance of graphite in commercial Li-ion batteries. Despite this attention, there are still questions about the atomistic structures of the intermediate states that exist during lithiation, especially when phase dynamics cause a disordered Li distribution. The Li migration event (diffusion coefficient of 10−5 nm2 ns−1) makes it difficult to explore the various Li-intercalation configurations in conventional molecular dynamics (MD) simulations with an affordable simulation timescale. To overcome these limitations, we conducted a comprehensive study using replica-exchange molecular dynamics (REMD) in combination with the ReaxFF force field. This approach allowed us to study the behavior of Li-intercalated graphite from any starting arrangement of Li at any value of x in LixC6. Our focus was on analyzing the energetic favorability differences between the relaxed structures. We rationalized the trends in formation energy on the basis of observed structural features, identifying three main structural features that cooperatively control Li rearrangement in graphite: Li distribution, graphite stacking mode and gallery height (graphene layer spacing). We also observed a tendency for clustering of Li, which could lead to dynamic local structures that approximate the staging models used to explain intercalation into graphite.

Graphical abstract: Replica exchange molecular dynamics for Li-intercalation in graphite: a new solution for an old problem

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Article information

Article type
Edge Article
Submitted
14 11 2023
Accepted
15 1 2024
First published
16 1 2024
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2024,15, 2745-2754

Replica exchange molecular dynamics for Li-intercalation in graphite: a new solution for an old problem

H. Park, D. S. Wragg and A. Y. Koposov, Chem. Sci., 2024, 15, 2745 DOI: 10.1039/D3SC06107H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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