Multi-Electron Redox Bipolar Small Molecule with Zn ²⁺ -Mediated Stabilization for Aqueous Zinc-Organic Batteries

The cycling stability of organic cathodes remains a major challenge for aqueous zinc-organic batteries. Here, we present a bipolar small molecule, NDI-T, which integrates a naphthalene diimide core with TEMPO radicals. This design enables highly stable multielectron redox reactions in a dilute 0.5 M Zn(OTf) 2 aqueous electrolyte. The Zn||NDI-T battery achieves a high specific capacity of 220 mAh g –1 at 0.2 A g –1 and exceptional cycling durability, retaining approximately 63 mAh g –1 after 10,000 cycles at a high current density of 10 A g –1 . Operando and ex situ spectroscopic analyses reveal a hybrid charge storage mechanism, where sequential Zn 2+ coordination and OTf – anion adsorption occur at distinct redox-active sites. Unlike in monovalent systems, Zn 2+ acts as a dynamic “molecular bridge,” chelating adjacent molecules to form a stable O–Zn 2+ –O cross-linked network that effectively suppresses dissolution while maintaining redox activity. This work demonstrates a feasible chelation-driven stabilization strategy to develop durable high-performance organic cathodes for aqueous zinc-organic batteries.