Terminally fluorinated ether as a solvent for high-performance lithium metal battery electrolyte.

Area of Science:

• Electrochemistry and Materials Science
• Advanced Battery Technology

Background:

• Lithium-metal batteries (LMBs) offer high energy density but face challenges with electrolyte stability and cycling performance.
• Developing compatible electrolytes is crucial for realizing the full potential of LMBs, particularly for next-generation energy storage.

Purpose of the Study:

• To investigate the performance of a novel electrolyte based on terminally fluorinated ether (5FDEE) for high-performance lithium-metal batteries.
• To evaluate the compatibility of 5FDEE with lithium hexafluorophosphate (LiPF6) and its impact on Li‖NMC811 cell stability.

Main Methods:

• Electrolyte formulation: A mixture of 1 M LiPF6 in 5FDEE:FEC (9:1 v/v) was prepared.
• Electrochemical testing: Li‖NMC811 cells were assembled and subjected to long-term cycling tests within a voltage window of 2.7-4.3 V vs. Li+/Li.

Main Results:

• The 5FDEE-based electrolyte demonstrated exceptional compatibility with LiPF6, facilitating high-performance LMBs.
• Li‖NMC811 cells exhibited remarkable cycling stability, maintaining an average coulombic efficiency over 99.9%.
• No capacity fading was observed over 550 cycles, indicating excellent long-term durability.

Conclusions:

• Terminally fluorinated ether (5FDEE) is a promising electrolyte component for advanced lithium-metal batteries.
• The developed electrolyte formulation significantly enhances cycling stability and efficiency, paving the way for practical LMB applications.