Ab initio Molecular Dynamics Simulations of the Initial Stages of Solid-electrolyte Interphase Formation on Lithium Ion Battery Graphitic Anodes

TL;DR

This study uses ab initio molecular dynamics to investigate how ethylene carbonate decomposes at graphite anodes in lithium-ion batteries, revealing rapid breakdown mechanisms influenced by edge terminations that match experimental observations.

Contribution

It provides new insights into the initial SEI formation process by identifying the role of carbon edge terminations and predicting decomposition pathways under realistic conditions.

Findings

Edge terminations are crucial for EC decomposition.

EC breakdown can occur rapidly under experimental conditions.

Decomposition products align with experimental observations.

Abstract

The decomposition of ethylene carbonate (EC) during the initial growth of solid-electrolyte interphase (SEI) films at the solvent-graphitic anode interface is critical to lithium ion battery operations. Ab initio molecular dynamics simulations of explicit liquid EC/graphite interfaces are conducted to study these electrochemical reactions. We show that carbon edge terminations are crucial at this stage, and that achievable experimental conditions can lead to surprisingly fast EC breakdown mechanisms, yielding decomposition products seen in experiments but not previously predicted.