Rational Design of Interfaces for High Current-Density Lithium Metal Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium metal anodes are crucial for high-energy-density batteries but suffer from dendrite growth, limiting practical application.
• Uncontrolled lithium dendrites cause short circuits and capacity fading, necessitating effective stabilization strategies.

Purpose of the Study:

• To develop and evaluate a trilayer protective coating for stabilizing lithium metal anodes.
• To enhance the cycling stability of lithium metal anodes at high current densities.

Main Methods:

• A trilayer coating composed of silver (Ag), lithium fluoride (LiF), and poly(ethylene oxide) (PEO) was rationally designed.
• The coating's components were optimized to facilitate Li+ transfer, suppress side reactions, and enhance mechanical integrity.
• Performance was evaluated using Li//Li symmetric cells and Li//LFP full cells under various current densities and cycling conditions.

Main Results:

• The trilayer coating demonstrated stable cycling of Li//Li symmetric cells for 1200 hours at 20 mA cm⁻².
• Li//LFP full cells achieved 1000 cycles at 1.09 mA cm⁻² and 80 cycles at 5 mA cm⁻².
• The coating effectively suppressed lithium dendrite growth and anode-electrolyte reactions.

Conclusions:

• The developed Ag/LiF/PEO trilayer coating provides a robust solution for stabilizing lithium metal anodes.
• This composite coating strategy, integrating alloyed, inorganic, and organic layers, offers a new pathway for designing stable solid electrolyte interphases (SEI).
• The findings pave the way for high-performance and safer lithium-metal-based batteries.