A Versatile Halide Ester Enabling Li-Anode Stability and a High Rate Capability in Lithium-Oxygen Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium-oxygen (Li-O₂) batteries offer high energy density but suffer from poor cathode rate capability and Li anode instability.
• Addressing these limitations is crucial for realizing next-generation battery technologies.

Purpose of the Study:

• To investigate the effects of an ester-based liquid additive, 2,2,2-trichloroethyl chloroformate, on Li-O₂ battery performance.
• To enhance both the rate capability of the oxygen cathode and the stability of the lithium metal anode.

Main Methods:

• Introduction of 2,2,2-trichloroethyl chloroformate into the conventional electrolyte of a Li-O₂ battery.
• Electrochemical performance testing, including rate capability and cycling stability measurements.
• Analysis of the solid-electrolyte interphase (SEI) layer on the Li anode.

Main Results:

• The Li-O₂ battery achieved an outstanding rate capability of 2005 mAh g^-1 at 1000 mA g^-1 with reduced charge potential.
• Improved Li₂O₂ solubility and O₂ diffusion rates contributed to enhanced rate capacity.
• The additive promoted a stable SEI layer on the Li anode, achieving over 900 h of cycling stability and 10 mAh cm^-2 Li capacity utilization.

Conclusions:

• 2,2,2-trichloroethyl chloroformate effectively enhances Li-O₂ battery performance by addressing key challenges.
• The additive improves cathode kinetics and Li anode cyclability, paving the way for high-energy-density applications.