Chelation Compensation Strategy for High‐Performance Iron‐Based Redox Flow Batteries

Iron‐based redox flow batteries (IRFBs) are compelling candidates for cost‐effective grid‐scale energy storage, benefiting from high safety, low cost, and the natural abundance of iron‐based active species. However, heterogeneous interface instability, side reactions, and kinetic deactivation lead to capacity decay and energy efficiency reduction, which limits the long‐term cycle stability of IRFBs. Chelation compensation is employed to regulate metal‐ion redox species through multidentate ligand design. Their coordination environment, solvation structure, and interfacial reactivity are thereby optimized, leading to improved energy efficiency and cycling stability. This review summarizes the major degradation mechanisms of IRFBs and highlights recent progress in chelation‐modified systems constructed with representative chelating functional groups. Particular attention is given to the influence of chelation on heterogeneous interface instability, side reactions, and reaction kinetics. Finally, current challenges and future directions in ligand design, electrolyte compatibility, mechanistic understanding, and practical implementation are discussed, offering guidance for the development of high‐performance chelation‐modified IRFBs for large‐scale energy storage.