Multiscale\nMXene Engineering for Enhanced Capacitive\nDeionization via Adaptive Surface Charge Tailoring

Abstract

Capacitive deionization (CDI), renowned for its eco-friendly\nand\nlow-energy approach to water treatment, encounters challenges in achieving\noptimal deionization efficiency and cycle stability despite recent\nadvancements. In this study, the CDI electrodes were crafted with\nmultilevel pore structures using modified cellulose (MCNF) and porous\nactivated MXene (PAMX), aiming to the impact of surface modification\non adsorption efficiency, stability, and overall performance. The\nexperimental results demonstrated the superiority of the electrode,\nspecifically the formulation integrating sulfonic acid-treated cellulose\nand PAMX (SCNF@PAMX). This configuration exhibited remarkably a higher\ndesalination rate (3.91 mg·g^–1·min^–1) and enhanced desalination capacity (31.24 mg·g^–1), with cycling performance exceeding 90%. Density\nfunctional theory calculations underscored the formidable adsorption\nenergy of SCNF for Na⁺ (2.15 eV), surpassing that of other\nmodified electrodes. The enhancement of deionization performance and\nefficiency through surface charge modification, altering Na⁺ electrostatic adsorption, lays a solid foundation for advancing\nmore efficient and durable seawater desalination technologies.