Elucidating electrolyte decomposition under electron-rich environments at the lithium-metal anode

Area of Science:

• Electrochemistry
• Materials Science
• Computational Chemistry

Background:

• Lithium-sulfur (Li-S) batteries are promising next-generation energy storage.
• Lithium metal anode stability is hindered by electrolyte decomposition and solid-electrolyte interphase (SEI) formation.
• Understanding electrolyte decomposition is key to improving Li-S battery performance.

Purpose of the Study:

• Investigate electrolyte decomposition mechanisms in Li-S battery systems.
• Determine the effect of electron-rich environments on electrolyte stability.
• Characterize the thermodynamics and kinetics of decomposition pathways.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Ab initio molecular dynamics (AIMD) simulations.
• Analysis of electrolyte species in pure DME and LiTFSI/LiFSI salt solutions.

Main Results:

• Pure 1,2-dimethoxyethane (DME) requires significant electron density for decomposition.
• Lithium salts readily react with excess electrons, and DME undergoes dehydrogenation.
• Oligomeric anionic species and thermodynamically favorable decomposition pathways with low activation barriers were identified.

Conclusions:

• Electrolyte decomposition in Li-S batteries is influenced by electron-rich conditions and salt reactivity.
• Decomposition pathways are thermodynamically favorable and kinetically accessible.
• Findings provide insights for designing stable electrolytes for advanced Li-S batteries.