Products Cited in Publications Worldwide Non-solvating Fluoroether-engineered acetate-based electrolyte for ultra-low-temperature lithium-ion batteries with stable graphite compatibility

Non-solvating Fluoroether-engineered acetate-based electrolyte for ultra-low-temperature lithium-ion batteries with stable graphite compatibility

Shahali, H; Rahman, M Akif; Suarez, Caleb; Luttenberg, Summer; Weston, Javen S; Amiri, Ahmad

DOI:

Abstract

Methyl acetate (MA) is a promising solvent due to its strong oxidative stability, low viscosity, and extremely low freezing point; however, its application is limited by poor compatibility with graphite. This study introduces a novel MA-based electrolyte with enhanced performance across a wide temperature range by modulating Li+–MA interactions through non-solvating mechanisms, thereby tailoring the solvation structure to enable low-temperature operation. The engineered electrolyte exhibits excellent compatibility with both graphite and Li-rich Nickel Manganese Cobalt (LiNMC) cathodes and remains in a stable liquid state down to −80 °C. A non-solvating fluoroether co-solvent is incorporated to compete with Li+ and partially disrupt MA solvation during graphite lithiation, enhancing desolvation efficiency and lowering desolvation energy. At optimized concentrations, this co-solvent promotes anion integration into the Li+ solvation shell, increasing the presence of free solvent molecules, contact-ion pairs (CIPs), aggregates (AGGs), and nanometric aggregates (n-AGGs). These changes reduce the band gap between LUMO and HOMO in the solvation shell, facilitating its reduction and promoting SEI formation via FSI− decomposition. Consequently, LiNMC/graphite cells retain over 90 % of their initial capacity after 150 cycles at −60 °C, while LiNMC811/graphite cells deliver a record-high capacity of 149.3 mAh/g.

Keywords

Low Temperature Batteries ; Methyl Acetate ; Non-solvating interactions ; Desolvation energy ; Fluoroether co-solvent

Purchased from AmBeed

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