Preparation and properties of two-dimensional Ti₂CT_xMXene based on electroetching method

The continuous advancements in wearable electronics have drawn significant attention toward 2D MXenes materials for energy storage owing to their abundant availability, adaptability, and distinctive physicochemical properties. Two unresolved concerns currently revolve around environmental pollution by F-containing etching and finite kinetics caused because of re-stacking of nanosheets. In this study, Al was electrochemically etched from porous Ti₂AlC electrodes without the use of fluorine, through a selective electrochemical etching process in dilute hydrochloric acid. Subsequently, Ti₂CT_xMXene was vertically grown on carbon fiber (CF) substrates. The resulting Ti₂CT_x@CF electrodes are lightweight, thin, and flexible, exhibiting a surface capacitance of 330 mF cm^-2at a constant current density of 1 mA cm^-2after 2000 cycles. They display a surface capacitance retention of 96.16% and a high energy density of 45.3μWh cm^-2at a power density of 0.497 mW cm^-2. These metrics underscore the Ti₂CT_x@CF electrode's commendable multifunctionality, electrochemical performance, ion transport efficiency, and charge storage capacity. Moreover, a flexible energy storage electrode material with a high area capacity was developed by combining Ti₂CT_xMXene nanosheets, possessing a large specific surface area, with a flexible carbon fabric substrate.