Borate-Based Artificial Solid-Electrolyte Interphase Enabling Stable Lithium Metal Anodes.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium (Li) metal anodes are crucial for high energy density batteries.
• Dendrite formation and interfacial instability hinder Li metal anode practical application.
• Existing solid-electrolyte interphases (SEI) often lack stability and uniform ion transport.

Purpose of the Study:

• To develop a novel borate-based artificial solid-electrolyte interphase (B-SEI) for Li metal anodes.
• To investigate the structure and properties of the B-SEI.
• To evaluate the electrochemical performance and stability of Li metal anodes protected by the B-SEI.

Main Methods:

• Synthesized B-SEI via reaction of metallic Li with triethylamine borane (TEAB).
• Characterized B-SEI structure using cryogenic electron microscopy (Cryo-EM).
• Evaluated electrochemical performance using symmetric Li cells and LiFePO4//Li full cells.

Main Results:

• The B-SEI exhibits a glass-crystal bilayer structure.
• The artificial SEI facilitates uniform Li-ion transport and inhibits dendrite growth.
• Symmetric Li cells with B-SEI maintained stable cycling for 700 h at 3 mA cm⁻².
• Full cells demonstrated minimal capacity decay after 500 cycles.

Conclusions:

• The borate-based artificial SEI effectively stabilizes Li metal anodes.
• This approach enhances rate performance and cycle life of Li metal batteries.
• The developed B-SEI represents a promising strategy for practical high-energy Li metal batteries.