An Ultrastable Aqueous Ammonium-Ion Battery Using a Covalent Organic Framework Anode

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous ammonium ion batteries offer safety and sustainability but face challenges in cycling stability.
• Lack of suitable anode materials, due to ammonium ion (NH4+) size causing structural damage, hinders battery development.

Purpose of the Study:

• To introduce a novel Aza-based covalent organic framework (COF) as a high-performance anode for aqueous ammonium ion batteries.
• To demonstrate the superior electrochemical performance and cycling stability of the COF anode.

Main Methods:

• Synthesis and characterization of an Aza-based COF material.
• Electrochemical testing of the COF as an anode in aqueous ammonium ion batteries.
• Assembly and evaluation of a full rocking-chair battery using the COF anode and a Prussian blue cathode.

Main Results:

• The Aza-based COF anode exhibits excellent ammonium storage capabilities and operates in a negative potential range (0.3 to -1.0 V vs. SCE).
• High capacity (≈74 mAh g⁻¹ at 10 A g⁻¹) and exceptional cycling stability (over 20,000 cycles at 1.0 A g⁻¹) were achieved with the COF anode.
• A full battery assembled with the COF anode and Prussian blue cathode retained 89% capacity over 20,000 cycles, outperforming existing ammonium ion batteries.

Conclusions:

• The developed Aza-based COF is a promising anode material for stable and high-performance aqueous ammonium ion batteries.
• This research provides valuable insights for designing advanced anode materials for next-generation energy storage systems.
• The findings pave the way for developing safer and more sustainable high-energy storage solutions.