Porous MXene (Ti₃C₂Tₓ) @ Redox-Active Covalent Organic Framework-Conductive Polymer Hybrid for Hybrid Capacitive Deionization Desalination

Abstract

Capacitive deionization (CDI) has emerged as a promising desalination technology owing to its energy efficiency, environmental sustainability, and operational simplicity. However, the development of advanced electrode materials with high electrosorption capacity and long cycling stability remains a key challenge. In this work, we report a novel hybrid electrode material composed of porous Ti₃C₂Tₓ MXene nanosheets integrated with a redox-active covalent organic framework (COF) and a conductive polymer, polyaniline (PANI), for hybrid capacitive deionization (HCDI). The hybrid composite exploits the high conductivity and surface area of MXene, the redox functionality and porous architecture of the COF, and the pseudocapacitive behavior of PANI, synergistically enhancing charge storage and ion removal. Structural, morphological, and electrochemical characterizations reveal superior charge transport, ion diffusion, and stable cycling. The HCDI performance exhibits a high salt adsorption capacity (SAC) of 37.6 mg/g in 500 mg/L NaCl, excellent rate capability, and longterm cycling stability over 100 cycles. This work provides a promising pathway for designing next-generation desalination electrodes by rational hybridization of functional materials.