Electrophoretic deposition of Ti₃C₂T_x MXene nanosheet N-carbon cloth as binder-free supercapacitor electrode material

Despite the existing advances of Ti₃C₂T_x MXene as supercapacitor electrode material, its capacitance can be further enhanced through the composite strategy. In this work, the nitrogen-doped superhydrophilic carbon cloth (ENCC) was firstly prepared by N-doping of carbon cloth (CC), and then Ti₃C₂T_x MXene nanosheets were electrophoretically deposited to yield the binder-free Ti₃C₂T_x(EPD)/ENCC as supercapacitor electrode material. As a result, the composite electrode exhibited an area-specific capacitance of 2080.1 mF·cm⁻² at 1 mA·cm⁻² current density. The analysis implied that the varying Ti valence states provided certain psedocapacitance to the capacitance of the as-prepared electrode, though the main contribution was still dominantly from the electric double layer capacitance (EDLC). Further, the assembled symmetric supercapacitor yielded a wide voltage window of 1.8 V, and a good cyclic stability with 91% capacitance retention after 10,000 charge/discharge cycles at 20 mA·cm⁻². Overall, the employed composite strategy enabled the good dispersion of the MXene flakes on the surface of the flexible substrate. Meanwhile, the large number of functional groups (-OH, -F, etc.) on the surface of Ti₃C₂T_x MXene interacted with the carbon layer through hydrogen bonding effects, which endows it as an ideal electrode for electrochemical capacitors.