Tuning the pore size distribution of Ti3C2Tx porous film for high capacity supercapacitor electrode

The closely restacked MXene nanosheets obstruct electrolyte ion transfer in electrodes, limmiting the electrochemical performance at a high charging-discharging rate. Although various 3D porous structures have been constructed, size effect of porous MXenes electrodes has been rarely studied. Herein, the classical metal ionassisted method was used to fabricate 3D porous MXene films. The pore size distribution was changed by adjusting the cation valency. Noteworthy, when the mesoporous pore size distribution is in the range of 5 - 10 nm, the porous structure can significantly improve the electrochemical performance and the presence of micropores can increase the proportion of surface capacitance. As a result, the porous Ti3C2Tx film treated by Mg2+ showed outstanding electrochemical performance, with both high capacity (420F/g at 2 mV/s) and good cyclic stability (94.4% retention after 5000 cycles). This work presents a study on how pore size distribution of porous MXene film effects the electrochemical performance and provides a reference for the design of 3D porous MXene electrodes.