Boron Quantum Dots Pillared Ti3 C2 Tx Membrane Electrode with High Rate Performance for Supercapacitor.

Abstract

A sonication-assisted liquid-phase preparation technique is developed to prepare boron quantum dots (BQDs) with a lateral size of 3nm in a solution of NMP and NBA; it shows a direct bandgap semiconductor with a bandgap of 3eV and a specific capacitance of 41Fg-1 . A BQDs(10)-Ti3 C2 Tx membrane electrode with excellent capacitance and high flexibility is prepared by using Ti3 C2 Tx nanosheets (NSs) as assembled units and BQDs as pillar; it gives a specific capacitance of 524Fg-1 at 1Ag-1 in 6m H2 SO4 electrolyte, a high capacity retention of 75%, and a minimum relaxation time of 0.51s. An all-solid-state BQDs(10)-Ti3 C2 Tx flexibility supercapacitor is assembled by using a BQDs(10)-Ti3 C2 Tx membrane as electrodes and PVA/H2 SO4 hydrogel as electrolyte; it not only shows an area specific capacitance of 552mFcm-2 at 1.25mAcm-2 , a retention rate of 75%, a capacity retention of 93% after 5000 cycles, and an energy density of 40.4Whcm-3 at a volume power density of 416Wcm-3 , but also provides superior flexibility and can be bent to different degrees, showing that the assembled BQDs(10)-Ti3 C2 Tx membrane electrode and BQDs(10)-Ti3 C2 Tx flexible supercapacitor display broad application prospects in field of portable/wearable electronic devices.