Enhanced Capacitive Deionization Performance of Ti3C2Tx/C via Structural Modification Assisted by PMMA-Derived Carbon Spheres

Introducing "spacer" materials into Ti3C2Tx layers is a powerful approach to reduce layer stacking and enhance the utilization of active sites in capacitive deionization (CDI). In this research, porous carbon spheres derived from polymethacrylates (PMMA) act as the "spacer" material, and the Ti3C2Tx/C composite is prepared through a straightforward technique of mixing followed by annealing. Through the cooperative effect of the "separation" of Ti3C2Tx nanosheets and the porous nature of the carbon spheres, Ti3C2Tx/C has a large specific surface area of 96.01 m2 g–1, a pore volume of 0.2306 cm3 g–1, and a well-developed mesoporous structure. Benefiting from the increased adsorption sites coupled with lower migration resistance, Ti3C2Tx/C achieves an ion adsorption capacity of 24.29 mg g–1 and ion adsorption rate of 0.0485 mg g–1 s–1 in 1000 μS cm–1 NaCl solution at 1.2 V, reflecting an increase of 76 and 166%, respectively, compared to m-Ti3C2Tx (13.8 mg g–1 and 0.0485 mg g–1 s–1). Besides, it is established that the ion adsorption process of Ti3C2Tx/C is more accurately described by the second-order kinetic module.