Liquid state properties of SEI components in dimethoxyethane

Area of Science:

• Battery Technology
• Materials Science
• Computational Chemistry

Background:

• The solid-electrolyte interphase (SEI) is vital for lithium metal battery performance.
• Understanding SEI properties, like dissolution, is crucial but experimentally challenging.
• Lack of fundamental data hinders SEI engineering for advanced energy storage.

Purpose of the Study:

• To investigate the dissolution behavior of key SEI components (LiF, Li₂O, LiOH, Li₂CO₃) in battery electrolytes.
• To computationally probe the solution-state characteristics of these SEI materials.
• To determine the relative stability of SEI components against electrolyte dissolution.

Main Methods:

• Utilized ab initio computational chemistry simulations.
• Employed ab initio molecular dynamics to study solvation structures.
• Analyzed results using radial distribution functions, solvation structure maps, and vibrational density of states to calculate free energies.

Main Results:

• Determined the free energy of dissolution for LiF, Li₂O, LiOH, and Li₂CO₃.
• Identified LiOH as the most likely component to dissolve, followed by LiF and Li₂CO₃.
• Found Li₂O to be the most stable SEI component concerning dissolution, though overall dissolution is not thermodynamically favored.

Conclusions:

• SEI dissolution is generally improbable under studied conditions.
• Lithium oxide (Li₂O) exhibits the highest stability against electrolyte dissolution, suggesting its potential for robust SEI formation.
• Computational insights provide a pathway for designing more stable SEI layers to enhance battery longevity and performance.