Design Principles for Fluorinated Interphase Evolution via Conversion-Type Alloying Processes for Anticorrosive...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium metal anodes are crucial for high-energy-density batteries.
• Reactivity and dendritic growth of lithium metal hinder practical application and battery lifespan.

Purpose of the Study:

• To engineer a stable interface for lithium metal anodes.
• To suppress lithium dendrite formation and enhance battery cycle life.

Main Methods:

• Interface engineering using conversion-type reactions of metal fluorides.
• Development of a LiF-modified Li-Mg-C electrode.
• Electrochemical cycling and analysis in organic electrolytes with and without fluoroethylene carbonate (FEC) additives.
• Utilizing phase diagrams to understand alloying mechanisms.

Main Results:

• The LiF-modified Li-Mg-C electrode exhibited stable cycling over 2000 hours with FEC additives and over 700 hours without additives.
• The strategy effectively suppressed unwanted side reactions and lithium dendrite growth.
• Solid-solution-based alloying facilitated spontaneous LiF layer and bulk alloy formation.
• Reversible lithium plating/stripping occurred inward to the bulk, unlike intermetallic compounds.

Conclusions:

• Interface engineering with LiF passivation and Li-M alloy formation is a viable strategy for stable lithium metal anodes.
• The LiF-modified Li-Mg-C electrode offers a promising solution for long-cycle life and high-energy batteries.
• Understanding alloying behavior through phase diagrams is key to designing advanced battery materials.