Enhanced pseudocapacitance of Ti3C2Tx MXene by UV photochemical doping

This work presents an ultraviolet-assisted photochemical doping strategy for realizing the modification of Ti3C2Tx MXene. In this strategy, nitrogen atoms are easily doped into Ti3C2Tx MXene, and harmful fluorine-containing terminal groups are effectively removed from the Ti3C2Tx MXene under UV light irradiation. The results further show that the nitrogen doping level is ∼2.99 at. %, and the interlayer spacing of Ti3C2Tx MXene increases from 1.271 to 1.363 nm after the nitrogen doping. The nitrogen-doped Ti3C2Tx MXene exhibits a higher specific capacitance of 491 F g−1 (1176 F cm−3) at 2 mV s−1 than raw Ti3C2Tx MXene (292 F g−1) when used as a supercapacitor electrode material. Moreover, a nitrogen-doped Ti3C2Tx quasi-solid-state supercapacitor device can yield an energy density of 14.9 Wh kg−1 at 750 W kg−1. Therefore, this work affords a simple and highly versatile route for fabricating high-performance MXene materials for supercapacitors.