Capacitive deionization (CDI) technologies, particularly hybrid CDI (HCDI) and pseudocapacitive deionization (PCDI) are emerging as efficient solutions for water desalination by utilizing advanced electrode materials. Recent advancements in 2D hybrid nanocomposites have shown great potential in improving ion adsorption capacity, charge efficiency, and cycling stability. These composites are designed using bimetallic nanoparticles, metal oxides, and conductive carbonaceous materials such as graphene, carbon nanotubes (CNTs), and graphitic carbon nitride (g-C₃N₄). Functionalization strategies, including metal doping (e.g., Ag, Cu, Mn) and incorporating nano clay minerals or metal-organic framework (MOF)-derived structures, optimize the balance between pseudocapacitive and electric double-layer charge storage mechanisms. As a result, these hybrid electrodes achieve high specific capacitance and enhanced salt adsorption capacity while operating under optimized voltage conditions. Their excellent ion selectivity and energy efficiency further contribute to CDI performance improvements. Moreover, the intrinsic hydrophilicity and structural robustness of these materials ensure stable cycling performance, maintaining high charge retention over multiple regeneration cycles. These findings underscore the potential of 2D hybrid nanocomposite electrodes in developing scalable and sustainable CDI systems, offering a highly efficient approach to water desalination with superior energy and material utilization.
