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

Aqueous ammonium ion batteries (AAIBs) are emerging as sustainable energy storage systems due to their inherent safety and eco-friendliness. Organic electrode materials demonstrate significant potential as anode materials due to their structural diversity, eco-friendly, and abundant redox-active moieties. However, their practical application is hindered by low specific capacity and poor cycling stability. In this study, we introduced 2,8,14-trinitrodiquinoxalino[2,3-a:2',3'-c]phenazine (HATNTN), a nitro-functionalized π-conjugated aromatic structure, as a host material for enhancing NH₄ ⁺ storage. The synergistic integration of nitro groups and aromatic frameworks enables dual enhancements: robust NH₄ ⁺ coordination via a two-step redox mechanism and enhanced dissolution resistance via hydrogen-bonding supramolecular network. HATNTN anode demonstrates a remarkable capacity of 203.4 mAh g^-1 at 1 A g^-1 and an exceptional cycle life of 30,000 cycles at 20 A g^-1. Moreover, HATNTN//VO300 full battery delivers a stable specific capacity of 106.2 mAh g^-1 over 30,000 cycles at 3 A g^-1, with a cycle life exceeding 2500 h and a capacity retention rate of 88.1%. Combining in situ spectroscopy and density functional theory calculations, we elucidate the critical role of nitro-induced hydrogen bonding in stabilizing NH₄ ⁺ storage interfaces. This study establishes a supramolecular design paradigm for durable organic anodes, advancing high-performance AAIBs toward practical applications.