Porous Cryo-Dried MXene for Efficient Capacitive Deionization

Aerogel-like, porous Ti3C2Tx MXene architecture electrode displayed a high electroadsorption capacity for capacitive deionization of saline water. A vacuum freeze-drying process was employed to prevent the restacking of MXene nanosheets due to van der Waals forces, leading to the formation of a porous structure with a large specific surface area. When applied as electrode materials for capacitive deionization, porous MXene demonstrated a high specific capacitance of 156 F/g and a volumetric capacitance of 410 F/cm3 in 1 M sodium chloride (NaCl) electrolyte. The porous Ti3C2Tx MXene electrodes can deliver a high electroadsorption capacity of 118 mg/cm3 (45 mg/g) in 10,000 mg/L NaCl solution (applied voltage: 1.2 V) and excellent cycling stability (up to 60 cycles) in comparison with the restacked MXene and activated carbon electrodes, indicating its promising potential for desalination applications.