CF₄ Plasma-Generated LiF-Li₂ C₂ Artificial Layers for Dendrite-Free Lithium-Metal Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Surface Chemistry

Background:

• Lithium metal anodes are ideal for high-energy storage but suffer from dendrite growth and volume changes.
• These issues limit the practical application of lithium metal batteries.

Purpose of the Study:

• To develop a facile and eco-friendly method for modifying lithium metal anode surfaces.
• To fabricate a novel artificial layer to suppress dendrite formation and improve cycling stability.

Main Methods:

• Carbon tetrafluoride (CF4) plasma treatment for lithium metal anode surface modification.
• Fabrication of a lithium fluoride (LiF) and lithium carbide (Li2C2) artificial layer.
• Electrochemical testing of symmetric cells and full batteries with LiFePO4 cathodes.

Main Results:

• The LiF-Li2C2 layer promotes uniform lithium nucleation and planar growth due to high LiF adsorption energy and low Li+ diffusion barriers in Li2C2.
• Symmetric cells demonstrated stable operation for over 6500 hours (2 mA cm-2) and 950 hours (1 mA cm-2).
• Full batteries achieved a high reversible capacity of 136 mAh g-1 at 1C with 97.2% capacity retention over 200 cycles.

Conclusions:

• CF4 plasma treatment effectively creates a dendrite-free lithium metal anode via a LiF-Li2C2 artificial layer.
• This approach offers a promising route for developing environmentally friendly and high-performance energy storage devices.
• The study highlights the potential of plasma technology in advancing battery technology.