Flexible Ti2C MXene film: Synthesis, electrochemical performance and capacitance behavior

Ti2C MXene film with good flexibility was successfully prepared which exhibits the highest gravimetric capacity in the currently reported MXene family. The coupling of oxygen functional groups with the adsorbed H on the surface of Ti2C MXene causes charge redistribution in the aqueous H2SO4 electrolyte, resulting in the dominance of pseudo-capacitance behavior. [Display omitted] •Flexible free-standing Ti2C MXene film is synthesized.•The Ti2C MXene film shows excellent specific capacitance as supercapacitor electrode compared with other reported MXenes.•A novel coupling mechanism is proposed based on the density functional theory (DFT). MXenes have attracted wide attention in the field of energy storage due to their high electrical conductivity, good hydrophilicity and diversified surface terminals. Herein, Ti2C MXene film with good flexibility is successfully prepared which exhibits excellent gravimetric capacity in the currently reported MXene family. And the coupling mechanism of the surface terminations of Ti2C MXene in aqueous electrolytes on the capacitance behavior is proposed. The flexible Ti2C film directly used as electrode for supercapacitors shows good electrochemical performance with specific capacitance up to 382F g−1 at 2 mV s−1 and 265F g−1 at 100 mV s−1, indicating that it is a promising electrode material for supercapacitors.