Redesigning Covalent Organic Framework Electrodes for Capacitive Deionization: A Step Forward in Electrochemical Desalination and Resource Recovery

High Resolution Image Download MS PowerPoint Slide Capacitive deionization (CDI) has emerged as a promising electrochemical technology for water desalination and ion recovery owing to its low energy consumption, modularity, and operational simplicity. However, the performance of conventional carbon-based electrodes remains constrained by inherent limitations in selectivity, stability, and redox activity. Covalent organic frameworks (COFs), crystalline, porous polymers composed of light elements and customizable linkers, offer a unique opportunity to engineer next-generation electrode materials with molecular precision. In this Perspective, we highlight recent advances in the rational design, functionalization, and hybridization of COF-based materials for CDI applications. We focus on three emerging categories: (i) cathodic COFs for enhanced sodium ion uptake in water desalination; (ii) cathodic COFs for selective recovery of metal ions from complex mixtures; and (iii) anodic COFs with redox-active moieties tailored for selective anion removal. Beyond summarizing these developments, we discuss key challenges in integrating COF chemistry into practical CDI systems, including intrinsic conductivity, scalable synthesis, cost-effectiveness, and long-term cyclic stability. COFs can serve as versatile and architecturally tunable platforms for CDI electrodes, enabling selective and energy-efficient operation with a potential relevance to sustainable resource recovery.