Covalent Organic Framework-Derived Ion-Sieving Channels Enabling Stable Lithium Metal Anodes through Interfacial...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Lithium metal anodes offer high capacity but face challenges with interfacial instability, parasitic reactions, and dendrite growth.
• These issues hinder the practical application of high-performance lithium metal batteries.

Purpose of the Study:

• To engineer a composite separator using a 2D covalent organic framework (NUS-9) to enhance lithium metal battery performance.
• To suppress interfacial instability and dendrite growth in lithium metal anodes.

Main Methods:

• Synthesized a 2D covalent organic framework (NUS-9) via cryogenic interfacial growth.
• Engineered NUS-9 into a NUS-9@PP composite separator for lithium metal batteries.
• Characterized the separator's structure, ion transport properties, and electrochemical performance using techniques like XPS.

Main Results:

• The NUS-9@PP separator exhibited vertically aligned Li+ transport channels and ion-sieving functionality.
• It suppressed electrolyte-Li parasitic reactions and regulated Li+ solvation structures.
• Demonstrated lower nucleation overpotentials (38.2/42.8 mV), extended electrochemical stability to 4.7 V, high Li+ transference number (0.71), and stable cycling (370 h at 3 mA cm-2).
• Promoted LiF-rich SEI formation, effectively suppressing lithium dendrite growth.

Conclusions:

• The engineered NUS-9@PP composite separator provides a novel strategy for stabilizing lithium metal anodes.
• This approach significantly enhances lithium metal battery cycling longevity and efficiency.
• The 2D COF material shows great potential for advancing next-generation energy storage devices.