Electrostatically induced reconstruction of the 3D nitrogen-doped Ti₃C₂T_x electrode and its excellent desalination performance for hybrid capacitive deionization

Capacitive deionization is a promising solution for freshwater production with Ti3C2Tx emerging as a momentous electrode material. Here, highly porous 3D nitrogen-doped Ti3C2Tx (3D-N-Ti3C2Tx) is developed by using electropositive melamine to electrostatically induce electronegative Ti3C2Tx nanosheets to be reconstructed to alleviate the severe stacking problem of Ti3C2Tx layers. 3D-N-Ti3C2Tx has a large specific surface area (129.48 m(2) g(-1)) and pore volume (0.372 cm(3) g(-1)), exposing numerous ion adsorption sites. Also, 3D-N-Ti3C2Tx achieves nitrogen doping, which greatly improves the hydrophilicity and electrical conductivity. With the combined advantages of a three-dimensional structure and nitrogen doping, 3D-N-Ti3C2Tx achieves a specific capacitance of 101.9 F g(-1) in 1 mol L-1 NaCl solution and demonstrates fantastic desalination performance with a high desalination capacity of 31.51 mg g(-1), surpassing those of the majority of reported Ti3C2Tx electrodes, and outstanding desalination cycling stability in 500 mg L-1 NaCl solution at 1.2 V. This work significantly contributes to the advancement of Ti3C2Tx electrode material in CDI.