Electrolyte Dependence of Li+ Transport Mechanisms in Small Molecule Solvents from Classical Molecular Dynamics
Name
JPCB_manuscript_Crabb_Aggarwal_et_al.pdf
Description
Accepted version
Size
9.44 MB
Format
Adobe PDF
Checksum (MD5)
ea84593377f3af709ab605a9730ac647
Author(s)
Crabb, Emily
Aggarwal, Abhishek
Stephens, Ryan
Shao-Horn, Yang
Leverick, Graham
Grossman, Jeffrey C.
Date Issued
March 29, 2024
Journal
The Journal of Physical Chemistry B
Publisher
American Chemical Society
Citation
J. Phys. Chem. B 2024, 128, 14, 3427–3441
Version
Author's final manuscript
Abstract
As demands on Li-ion battery performance increase, the need for electrolytes with high ionic conductivity and a high Li+ transference number (tLi) becomes crucial to boost power density. Unfortunately, tLi in liquid electrolytes is typically <0.5 due to Li+ migrating via a vehicular mechanism, whereby Li+ diffuses along with its solvation shell, making its diffusivity slower than the counteranion. Designing liquid electrolytes where the Li+ ion diffuses independently of its solvation shell is of significant interest to enhance the transference number. In this work, we elucidate how the properties of the solvent influence the Li+ transport mechanism. Using classical molecular dynamics simulations, we find that a vehicular mechanism can be increasingly preferred with a decreasing solvent viscosity and increasing interaction energy between the solvent and Li+. Thus, a weaker interaction energy can enhance tLi through a solvent-exchange mechanism, ultimately improving Li-ion battery performance. Finally, metadynamics simulations show that in electrolytes where a solvent-exchange mechanism is preferable, the energy barrier to changing the coordination environment of Li+ is much lower than in electrolytes where a vehicular mechanism dominates.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Research Laboratory of Electronics
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Creative Commons Attribution-Noncommercial-ShareAlike
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DOI of Published Version
https://doi.org/10.1021/acs.jpcb.3c07999
