Crafting an\nExceptionally Redox-Active Organic Molecule Boasting Superior Electron\nMobility for High-Performance Electrochemical Desalination

Access to freshwater is crucial for a sustainable environment\nand human ecosystems. Hybrid capacitive deionization (HCDI) based\non attractive pseudocapacitive reactions is considered a promising\nenvironmentally friendly and energy-saving electrochemical desalination\ntechnology. However, the application of HCDI technology is still limited,\nmainly due to the unsatisfactory ion adsorption ability of the pseudocapacitive\nelectrode. Herein, we unveil an innovative redox-active organic molecule\n(PATD) that showcases outstanding pseudocapacitive properties for\nelectrochemical desalination. Notably, the integration of redox-active\nCO and CN groups in the PATD molecule promotes stable\nand efficient pseudocapacitive reactions. Additionally, the rigid\nmolecular structure, combined with a minimal HOMO–LUMO energy\ngap, ensures exceptional redox characteristics and superior electron\ntransfer capability of the PATD molecule, which are substantiated\nby experimental evidence and theoretical studies. As an electrode,\nthe PATD molecule exhibits significant pseudocapacitive characteristics\nalong with excellent long-term stability, retaining 89.0% of its capacitance\nafter 5000 cycles in a NaCl aqueous solution. In practical applications,\nthe developed HCDI device incorporating the PATD electrode demonstrates\na remarkably high salt removal capacity of 56.9 mg g<sup>–1</sup>, a swift average removal rate of 1.9 mg g<sup>–1</sup> min<sup>–1</sup>, and consistent regeneration performance while attaining\nreliable energy recovery, which highlights its promising prospects\nfor sustainable desalination technologies.