Boosted Durability and Diffusion Kinetics of High‐Potential Azopyridines for Aqueous Organic Flow Batteries

High-potential organic redox-active molecules are crucial for high-energy-density aqueous organic flow batteries (AOFBs). Azopyridine (AZO) derivatives with high redox potential (0.86 V vs. SHE) suffer from structural rearrangement instability and slow redox kinetics during the oxidation process. Herein, we achieve dual-target modulation of the electronic structure and dynamic steric hindrance, which increases the bond energy of the azo bond and buffers the drastic change of redox-induced molecular structure. Thus, the azo bond cleavage and nucleophilic side reactions were suppressed, thereby simultaneously promoting the redox potential (0.9 V vs. SHE) and stability. Further modulation of the solvation shell anions also alleviates molecular aggregation and minimizes solvation reorganization energy, thereby markedly increasing the cell energy efficiency by ∼60%. The AZO-based AOFB demonstrated robust durability for 7000 cycles (>1400 h). Impressively, the cell sustained over 1250 cycles at high electron concentrations of 2.4 M, achieving an energy density of 70.4 Wh Lcatholyte ⁻¹. This work establishes an integrated molecular and solvation-structure design paradigm for realizing durable and high-energy-density AOFBs.