Molecular Design and Redox Chemistries for Aqueous Organic Redox Flow Batteries (AORFBs)

Aqueous organic redox flow batteries (AORFBs), utilizing redox-active organic materials as energy storage materials, represent a promising frontier for sustainable long-duration energy storage. This review highlights recent advances in redox-active molecule design, analyzing how molecular structures govern electrochemical behavior and degradation pathways critical to stability. We categorize systems by positive and negative electrolyte pairings, examining performance and lifetime challenges across configurations. We explore molecular engineering approaches and full-cell assembly principles to extend battery lifetime. By introducing representative studies within each category of redox couples, we outline state-of-the-art developments and establish rational design and pairing principles. This framework proposes guidelines for selecting compatible electrolyte pairs based on molecular properties of organic redox-active species, which may contribute to advancing stable materials and higher-performance AORFBs.