New families of materials that may potentially replace dominant carbon electrodes have emerged as a major research hotspot in the field of capacitive deionization (CDI). Here, we report a metal–organic framework (MOF)/polypyrrole (PPy) hybrid, in which conductive PPy nanotubes that are running through each MOF particle have the potential to increase the overall bulk electrical conductivity, thus promoting such a system as a good CDI electrode material. Consequently, the MOF/PPy hybrid shows a high desalination capacity of 11.34 mg g⁻¹, which is amongst those of state-of-the-art CDI electrodes. Moreover, the MOF/PPy hybrid also shows a superior desalination performance for brackish water and good cycling stability, far exceeding typical carbon-based benchmarks. This is the first example of CDI electrodes derived from direct MOF-based materials, highlighting the potential of these hybrid systems as promising materials beyond traditional carbon electrodes.

Importance of monomer symmetry, planarity, and nitrogen content in the crystallinity, surface area, and CO ₂ uptake has been studied for two series of 2D-COFs.