Molecular‐Level Design of Organic and Emerging Porous Framework Cathodes for Aqueous Zinc‐Ion Batteries

ABSTRACT Aqueous zinc‐ion batteries (AZIBs) are increasingly recognized as a highly pragmatic and imperative trajectory for sustainable, grid‐scale electrochemical energy storage. The global transition toward renewable energy mandates storage systems that circumvent the thermal runaway hazards, severe supply chain fragilities, and prohibitive costs inherent to non‐aqueous lithium‐ion systems. However, the commercial deployment of AZIBs is fundamentally bottlenecked by the intrinsic physical chemistry limitations of traditional inorganic cathodes. During the repeated intercalation of multivalent Zn 2+ ions, these dense, rigid frameworks routinely suffer from intense electrostatic diffusion barriers, irreversible lattice strain, and thermodynamically driven transition metal dissolution. To overcome the unyielding rigidity of inorganic crystal lattices, a profound paradigm shift has directed contemporary materials science toward the atomic‐level molecular design of soft organic small molecules, extended polymeric networks, and emerging highly porous frameworks—specifically two‐dimensional transition metal carbides/nitride, metal‐organic frameworks, and covalent organic frameworks. These materials possess structural tunability, intrinsic mechanical flexibility, and an abundance of customizable redox‐active sites. This comprehensive review provides a highly granular, physical chemistry‐driven analysis of the charge storage mechanisms inherent to these soft and porous architectures. We meticulously track the transition from classical solid‐state intercalation models to dynamic coordination/chelating chemistry, synergistic proton/zinc co‐storage, and surface‐dominated pseudocapacitive kinetics. Furthermore, we critically evaluate cutting‐edge molecular engineering strategies—encompassing frontier molecular orbital modulation, backbone conjugation extension, dynamic covalent cross‐linking, reticular structural design, and spatial nanoconfinement—that have been deployed to eradicate active material dissolution and amplify intrinsic electronic conductivity. We specifically focus on the critical advancements made between 2020 and 2026, leveraging insights from advanced in‐situ and operando characterization techniques. Finally, we address the translational macro‐engineering hurdles associated with these materials, particularly evaluating the volumetric energy density trade‐off, low tap density implications, and high‐loading thick electrode compatibility, proposing a data‐driven blueprint for the industrialization of next‐generation organic and framework‐based AZIBs.