Nitrogen Ion Implantation-Modified Cu Substrate for Stable Lithium Metal Anode

Area of Science:

• Materials Science
• Electrochemistry
• Surface Engineering

Background:

• Copper (Cu) foil is the standard current collector for lithium metal anodes (LMA) due to its commercial availability.
• Limitations of Cu foil include poor lithium affinity and non-uniform crystal faces, leading to lithium dendrite growth and reduced battery cyclability.
• Developing stable and efficient LMAs is crucial for next-generation high-energy-density batteries.

Purpose of the Study:

• To modify the Cu foil surface using an industrial-applicable ion implantation technique.
• To enhance lithium nucleation and deposition on the Cu substrate.
• To improve the cycling stability and rate capability of lithium metal anodes.

Main Methods:

• Surface modification of Cu foil via high-energy N+ plasma ion implantation.
• Characterization of the modified interface and solid electrolyte interphase (SEI) formation.
• Electrochemical testing of full cells utilizing the modified Cu foil as the LMA substrate.

Main Results:

• Formation of a nitrogen-rich (N-rich) transition interface with lithiophilic CuN with uniform crystal faces.
• Induction of a Li3N-rich SEI layer with high ionic conductivity, promoting uniform Li deposition and suppressing dendrite growth.
• Demonstrated uniform lithium nucleation/deposition, significantly enhanced cycling stability, and improved rate capability in full cells.

Conclusions:

• Ion implantation is an effective method for surface modification of Cu foil for LMAs.
• The N-rich interface and Li3N-rich SEI contribute to superior LMA performance and stability.
• This technique shows potential for broader application in addressing challenges in metal anode development.