Strategic Surface Engineering of Lithium Metal Anodes: Simultaneous Native Layer Elimination and Protective Layer...

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Lithium (Li) metal anodes offer high theoretical capacity but suffer from dendrite growth due to native layer formation and uneven Li+ flux.
• The native layer on Li metal impedes ion transport and compromises battery safety and lifespan.

Purpose of the Study:

• To develop a gas-solid reaction strategy for modifying the Li metal surface.
• To remove the native layer and form a stable, ionically conductive solid electrolyte interphase (SEI).

Main Methods:

• Vaporization of perfluorooctyltriethoxysilane (PFOTES) for gas-solid reaction with the Li metal surface.
• Characterization of the modified Li metal surface and SEI layer properties.
• Electrochemical testing of PFOTES-modified Li metal anodes in full cells.

Main Results:

• PFOTES treatment effectively removed the native layer and formed a homogeneous SEI.
• The exchange current density of PFOTES-modified Li (PFOTES-Li) increased 20-fold compared to Bare-Li.
• PFOTES-Li anodes demonstrated mitigated Li pulverization and dead Li formation during cycling.
• A full cell utilizing PFOTES-Li achieved a discharge capacity of 203.4 mAh g-1 at a high areal loading.

Conclusions:

• Gas-solid reaction using PFOTES is a viable strategy for stabilizing Li metal anodes.
• The formed SEI layer enhances Li+ conductivity and mechanical stability.
• This approach significantly improves the cycling stability of Li metal batteries.