Stable Lithium Oxygen Batteries Enabled by Solvent-diluent Interaction in N,N-dimethylacetamide-based Electrolytes

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Developing electrolytes for ultrahigh-energy-density lithium-oxygen (Li-O2) batteries requires stability against strong oxidation.
• N,N-dimethylacetamide (DMA) offers resistance to reactive oxygen species but has poor Li metal anode compatibility.

Purpose of the Study:

• To enhance the stability and performance of Li-O2 batteries by creating a novel electrolyte.
• To address the limitations of DMA in Li-O2 battery applications.

Main Methods:

• Incorporation of methyl nonafluorobutyl ether (M3) into a DMA-based electrolyte to form a localized high concentration electrolyte.
• Investigating the structural and chemical properties of the M3 diluent and its interaction with DMA.
• Analyzing the formation of the solid electrolyte interphase (SEI) on the Li anode.

Main Results:

• The DMA/M3 electrolyte demonstrated enhanced stability against O2- and 1O2 attacks due to stable C-F and CH3 bonds in M3.
• Intermolecular interactions between DMA and M3 promoted the formation of an anion-derived, inorganic-rich SEI, improving Li anode stability.
• Li-O2 batteries with the DMA/M3 electrolyte exhibited superior cycling performance at 30°C (359 cycles) and -10°C (120 cycles).

Conclusions:

• The rationally designed DMA/M3 electrolyte effectively overcomes the limitations of DMA for Li-O2 batteries.
• The localized high concentration electrolyte strategy significantly enhances Li anode protection and overall battery performance.
• This approach offers a promising pathway for next-generation ultrahigh-energy-density Li-O2 battery development.