A highly stable LiNO₃/N-methylacetamide deep eutectic electrolyte for rechargeable Li-O₂ batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium-oxygen (Li-O2) batteries offer high theoretical energy density but face challenges in cycle life and electrolyte stability.
• Developing stable electrolytes that facilitate efficient lithium anode cycling and oxygen reduction/evolution reactions is crucial.

Purpose of the Study:

• To develop a novel deep eutectic electrolyte (DEE) for Li-O2 batteries.
• To investigate the role of high LiNO3 concentration and hydrogen bonding in electrolyte performance.
• To evaluate the cycling stability and efficiency of Li-O2 batteries utilizing the developed DEE.

Main Methods:

• Synthesis of a deep eutectic electrolyte (DEE) comprising LiNO3 and N-methylacetamide (NMA).
• Characterization of electrolyte properties, focusing on hydrogen bonding and LiNO3 solubility.
• Electrochemical testing of Li-O2 cells, including cycling performance and capacity retention.

Main Results:

• A stable LiNO3-NMA DEE was successfully prepared, enabling a high LiNO3 concentration of 3.2 M.
• The DEE demonstrated excellent compatibility with the lithium anode and acted as an effective oxidation mediator.
• The Li-O2 batteries achieved remarkable cycling stability, completing 380 cycles at 200 mA g-1 with a capacity of 1000 mA h g-1.

Conclusions:

• The LiNO3-NMA DEE shows significant promise for high-performance and stable Li-O2 battery applications.
• The strong hydrogen bonding in the DEE is key to its enhanced properties and compatibility.
• This work presents a viable electrolyte strategy for advancing lithium-oxygen battery technology.