Ether-Oxygen Groups Modified Carboxylic Ester Enabling High-Voltage Lithium Metal Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium metal batteries (LMBs) offer high energy density but face capacity degradation due to electrolyte decomposition at high voltages.
• Developing stable electrolytes is crucial for advancing high-performance LMBs.

Purpose of the Study:

• To introduce propylene glycol monomethyl ether acetate (PMA) as a novel solvent for LMB electrolytes.
• To investigate the impact of PMA on electrolyte solvation structure and interfacial behavior.
• To enhance the stability and performance of LMBs at high cut-off voltages.

Main Methods:

• Formulation of PMA-based electrolytes with dual salts.
• Electrochemical cycling of Li||LiNi0.8Co0.1Mn0.1O2 (NCM811) batteries at 4.5 V and 60 °C.
• Molecular interfacial modeling to elucidate electrolyte-electrode interactions.

Main Results:

• The PMA-based electrolyte demonstrated stable cycling performance for over 100 cycles at a high cut-off voltage of 4.5 V.
• The battery retained 90.1% of its initial capacity at 60 °C.
• The unique ether-oxygen functionality of PMA promotes contact ion pairs (CIPs), enhancing electrolyte stability.

Conclusions:

• PMA is a promising solvent for developing high-performance LMB electrolytes.
• The study provides insights into electrolyte design for stable high-voltage lithium metal batteries.
• The findings contribute to advancing energy storage technologies.