Reaction dynamics of lithium-mediated electrolyte decomposition using machine learning potentials

Fuente: arXiv
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Main Authors: Kundu, Sohang, Chamaki, Diana, Ye, Hong-Zhou, Agarwal, Garvit, Berkelbach, Timothy C.
Format: Preprint
Published: 2025
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author Kundu, Sohang
Chamaki, Diana
Ye, Hong-Zhou
Agarwal, Garvit
Berkelbach, Timothy C.
author_facet Kundu, Sohang
Chamaki, Diana
Ye, Hong-Zhou
Agarwal, Garvit
Berkelbach, Timothy C.
contents We study the ring-opening decomposition of ethylene carbonate in the presence of a single lithium atom and on the surface of lithium metal. Combining accurate electronic structure theory, enhanced sampling, and machine learning, we fine-tune the MACE-MP0 foundation model and apply the resulting machine learning potentials to obtain statistically converged free energy profiles and reaction rates. We confirm that the level of electronic structure theory is important, and inaccurate density functionals can overestimate the reaction rate by up to nine orders of magnitude. We also find that harmonic transition state theory underestimates reaction rates by about one order of magnitude. For the surface reaction, we find and characterize a new, ultrafast decomposition pathway wherein the carbonyl is deeply inserted into the lithium surface and bent by about 70$^\circ$. This reaction, which occurs in a few tens of picoseconds, generates a ring-opened intermediate that is a precursor for CO or CO$_2$ formation; by contrast, an alternative pathway that yields CO$_3^{2-}$ and ethylene is found to be non-competitive, occurring on a timescale of tens of nanoseconds.
format Preprint
id arxiv_https___arxiv_org_abs_2509_14067
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Reaction dynamics of lithium-mediated electrolyte decomposition using machine learning potentials
Kundu, Sohang
Chamaki, Diana
Ye, Hong-Zhou
Agarwal, Garvit
Berkelbach, Timothy C.
Chemical Physics
Materials Science
We study the ring-opening decomposition of ethylene carbonate in the presence of a single lithium atom and on the surface of lithium metal. Combining accurate electronic structure theory, enhanced sampling, and machine learning, we fine-tune the MACE-MP0 foundation model and apply the resulting machine learning potentials to obtain statistically converged free energy profiles and reaction rates. We confirm that the level of electronic structure theory is important, and inaccurate density functionals can overestimate the reaction rate by up to nine orders of magnitude. We also find that harmonic transition state theory underestimates reaction rates by about one order of magnitude. For the surface reaction, we find and characterize a new, ultrafast decomposition pathway wherein the carbonyl is deeply inserted into the lithium surface and bent by about 70$^\circ$. This reaction, which occurs in a few tens of picoseconds, generates a ring-opened intermediate that is a precursor for CO or CO$_2$ formation; by contrast, an alternative pathway that yields CO$_3^{2-}$ and ethylene is found to be non-competitive, occurring on a timescale of tens of nanoseconds.
title Reaction dynamics of lithium-mediated electrolyte decomposition using machine learning potentials
topic Chemical Physics
Materials Science
url https://arxiv.org/abs/2509.14067