Bridging electrochemical desalination and energy storage: Coordination chemistry of organic electrode materials for capacitive deionization and aqueous batteries

Organic materials are attracting attention as tunable electrodes for capacitive deionization (CDI) and aqueous batteries, owing to their structural designability, abundant redox-active sites, and resource sustainability. This review systematically presents progress on three classes of organic materials, namely polymers, frameworks (COFs and MOFs), and small molecules, in these two technologies, with an emphasis on the structure–property–performance and coordination relationships that govern ion capture and charge storage. We establish a unified cross-disciplinary framework linking CDI and battery design principles, a perspective previously missing from the literature. In CDI, molecular engineering of redox centers, conducting polymers, and ion-exchange functionalities delivers high desalination capacity, ion selectivity, and cycling stability. In aqueous batteries, design strategies overcoming dissolution, structural collapse, and sluggish kinetics of inorganic electrodes yield markedly enhanced capacity and extended lifespan. Comparative analysis highlights the conceptual convergence in electrode design and coordination chemistry across three classes, underscoring the enabling role of organic materials as a bridge between electrochemical desalination and energy storage. Persistent challenges including low intrinsic conductivity, high synthesis cost, and scalable production are identified. Future directions involving AI-assisted design, green synthesis, and integrated water–energy devices are outlined to guide next-generation electrodes for sustainable water treatment and energy storage.