Nitrogen-Induced Hydrogen Bonding Supramolecular Network for Ultra-Stable Ammonium Ion Storage

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Aqueous ammonium ion batteries (AAIBs) offer safe and eco-friendly energy storage.
• Organic electrode materials show promise for AAIB anodes but suffer from low capacity and poor stability.
• 2,8,14-trinitrodiquinoxalino[2,3-a:2',3'-c]phenazine (HATNTN) is a nitro-functionalized π-conjugated aromatic structure.

Purpose of the Study:

• To develop a durable organic anode material for enhanced ammonium ion (NH₄⁺) storage in AAIBs.
• To investigate the synergistic effects of nitro groups and aromatic frameworks on electrochemical performance.
• To establish a supramolecular design strategy for high-performance organic anodes.

Main Methods:

• Synthesis and characterization of HATNTN as an anode material.
• Electrochemical testing of HATNTN in AAIBs, including galvanostatic cycling and rate capability tests.
• In situ spectroscopy and density functional theory (DFT) calculations to elucidate storage mechanisms.

Main Results:

• HATNTN anode exhibits a capacity of 203.4 mAh g^-1 at 1 A g^-1 and 30,000 cycles at 20 A g^-1.
• A HATNTN//VO300 full battery maintains 106.2 mAh g^-1 over 30,000 cycles at 3 A g^-1 with 88.1% capacity retention.
• Nitro-induced hydrogen bonding stabilizes NH₄⁺ storage interfaces, enhancing cycling stability.

Conclusions:

• HATNTN is a promising organic anode material for high-performance and durable AAIBs.
• Supramolecular design, particularly hydrogen bonding, is crucial for improving organic anode stability.
• This work provides a new paradigm for designing advanced organic electrodes for sustainable energy storage.