Covalent Organic Framework with 3D Ordered Channel and Multi-Functional Groups Endows Zn Anode with Superior...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Aqueous Zn-ion batteries (AZIBs) are crucial for sustainable energy, but their performance is limited by zinc dendrite growth and side reactions.
• Developing robust zinc metal anodes is key to advancing AZIB technology for a carbon-neutral future.

Purpose of the Study:

• To engineer a stable artificial solid electrolyte interface (SEI) for zinc metal anodes in AZIBs.
• To suppress uncontrolled zinc deposition and detrimental side reactions, thereby improving battery cycle life and efficiency.

Main Methods:

• Fabrication of a fluorinated zincophilic covalent organic framework with sulfonic acid groups (COF-S-F) as an interlayer on Zn metal (Zn@COF-S-F).
• Characterization of the COF-S-F interlayer's effect on zinc ion desolvation and transport.
• Testing of Zn@COF-S-F symmetric cells and Zn@COF-S-F|MnO2 full cells under various current densities and cycle counts.

Main Results:

• The Zn@COF-S-F anode exhibited dendrite-free morphology and suppressed side reactions.
• Symmetric cells demonstrated stable cycling for 1,000 hours with low voltage hysteresis (50.5 mV at 1.5 mA cm⁻²).
• Full cells achieved a discharge capacity of 206.8 mAh g⁻¹ at 1.2 A g⁻¹ after 800 cycles with 87.9% capacity retention.

Conclusions:

• The developed artificial SEI effectively regulates zinc deposition and mitigates side reactions.
• Targeted design of artificial SEI layers is a promising strategy for practical high-performance AZIBs.
• This approach significantly advances the potential of AZIBs for large-scale energy storage applications.