Boron Quantum Dots Pillared Ti3C2Tx Membrane Electrode with High Rate Performance for Supercapacitor

Abstract

AbstractA sonication‐assisted liquid‐phase preparation technique is developed to prepare boron quantum dots (BQDs) with a lateral size of 3 nm in a solution of NMP and NBA; it shows a direct bandgap semiconductor with a bandgap of 3 eV and a specific capacitance of 41 F g−1. A BQDs(10)‐Ti3C2Tx membrane electrode with excellent capacitance and high flexibility is prepared by using Ti3C2Tx nanosheets (NSs) as assembled units and BQDs as pillar; it gives a specific capacitance of 524 F g−1 at 1 A g−1 in 6 m H2SO4 electrolyte, a high capacity retention of 75%, and a minimum relaxation time of 0.51 s. An all‐solid‐state BQDs(10)‐Ti3C2Tx flexibility supercapacitor is assembled by using a BQDs(10)‐Ti3C2Tx membrane as electrodes and PVA/H2SO4 hydrogel as electrolyte; it not only shows an area specific capacitance of 552 mF cm−2 at 1.25 mA cm−2, a retention rate of 75%, a capacity retention of 93% after 5000 cycles, and an energy density of 40.4 Wh cm−3 at a volume power density of 416 W cm−3, but also provides superior flexibility and can be bent to different degrees, showing that the assembled BQDs(10)‐Ti3C2Tx membrane electrode and BQDs(10)‐Ti3C2Tx flexible supercapacitor display broad application prospects in field of portable/wearable electronic devices.