A rechargeable Li-O2 battery using a lithium nitrate/N,N-dimethylacetamide electrolyte

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Rechargeable lithium-oxygen (Li-O2) batteries face challenges with electrolyte stability at the O2 electrode.
• Polar, aprotic solvents like straight-chain alkyl amides resist O2 electrode degradation but fail to form a stable solid-electrolyte interphase (SEI) on the Li anode.
• Instability of the SEI leads to rapid Li metal and solvent decomposition.

Purpose of the Study:

• To demonstrate successful cycling of a Li anode in N,N-dimethylacetamide (DMA) by stabilizing the SEI.
• To develop a compatible electrolyte system for both electrodes in a Li-O2 battery.
• To potentially eliminate the need for ceramic membranes to protect the Li anode.

Main Methods:

• Utilized lithium nitrate (LiNO3) as a salt additive to stabilize the SEI in DMA.
• Assembled and cycled a Li-O2 cell with the novel electrolyte composition.
• Monitored cycling performance, capacity retention, charging profiles, and gaseous products.

Main Results:

• Achieved over 2000 hours (>80 cycles) of stable Li anode cycling at 0.1 mA/cm2.
• Demonstrated consistent charging profiles and good capacity retention.
• Identified O2 as the primary gaseous product during charging, indicating efficient oxygen utilization.

Conclusions:

• The LiNO3 additive successfully stabilizes the SEI in DMA, enabling long-term Li anode cycling.
• This electrolyte system shows promise for advancing rechargeable Li-O2 battery technology.
• The findings may obviate the need for separate anode protection in Li-O2 cells.