In situ fluoro-oxygen codoped graphene layer for high-performance lithium metal anode

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Traditional lithium-ion batteries lack the energy density for emerging technologies.
• Lithium-metal batteries (LMBs) offer high energy density but suffer from dendrite formation, low coulombic efficiency, and safety concerns.
• Uniform lithium plating is critical for stable LMB performance.

Purpose of the Study:

• To develop a modified current collector for enhanced lithium metal battery performance.
• To address the challenges of dendrite formation and low coulombic efficiency in LMBs.
• To improve the safety and cycling stability of lithium metal batteries.

Main Methods:

• Modification of a copper current collector with fluoro-oxygen codoped graphene (FGO@Cu).
• Investigation of FGO coating's effect on nucleation sites and current density distribution.
• Analysis of the solid electrolyte interphase (SEI) formation and lithium plating behavior.
• Electrochemical testing of FGO@Cu in symmetrical batteries and LiFePO4 full cells.

Main Results:

• FGO@Cu provides more even nucleation sites, reducing local effective current density.
• FGO modification promotes the formation of a stable LiF-rich SEI layer.
• Uniform lithium plating was achieved on the FGO@Cu current collector.
• FGO@Cu demonstrated a high coulombic efficiency (97% over 250 cycles) and long cycle life (over 650 hours in symmetrical cells).
• LiFePO4 full cells with FGO@Cu anodes showed superior cycling stability.

Conclusions:

• Fluoro-oxygen codoped graphene modification of copper current collectors significantly enhances lithium metal battery performance.
• The FGO@Cu current collector effectively suppresses dendrite growth and improves coulombic efficiency and safety.
• This approach offers a promising strategy for developing high-performance and reliable next-generation lithium metal batteries.