Rational Molecular Design of a Multi-Electron Organic Anode via Rapid Microwave Synthesis for Ultrastable NH₄ ⁺...

Aqueous ammonium-ion batteries (AAIBs) are promising energy storage devices, yet their development is hindered by the lack of high-performance electrode materials. While small-organic molecules possess structural tunability and diverse redox activity, their application is often limited by tedious synthesis, insufficient active-sites, and dissolution in electrolytes. Herein, we synthesize a small-organic molecule, DNQP, featuring multiple C═O/C═N redox-active centers, via a rapid microwave route. This method completes the condensation between -NH₂ and C═O in 40 min (vs. 72 h for solvothermal), simultaneously introducing additional redox-active C═N bonds and extending the π-conjugated framework. Electronic structure analyses reveal that DNQP possesses an ultranarrow bandgap (1.053 eV), a highly delocalized π-conjugated framework, and favorable π-π stacking channels for charge transport. These features, combined with a chelation-coordination storage mechanism, enhance electron transfer, structural stability, and multi-electron reactivity. As a result, DNQP achieves 79% redox-site utilization, delivering a four-electron capacity of 155.9 mAh g^-1 at 0.1 A g^-1, and exhibits remarkable cycling performance over 12 000 cycles at 5 A g^-1. A DNQP//α-MnO₂ full-cell retains 99% capacity after 2000 cycles. Mechanism studies elucidate a reversible two-step, four-electron NH₄ ⁺ storage process governed by N─H⋯O/N─H⋯N H─bonding. This work offers a rational molecular design and rapid synthesis for high-performance AAIBs organic materials.