Microwave-assisted efficient exfoliation of MXene and its composite for high-performance supercapacitors

MXene, as a promising electrode material, exhibits outstanding performance in supercapacitors because of its excellent chemical and physical properties. However, the conventional inefficient exfoliation methods and the blocked ion transmission channels caused by self-weight accumulation of MXene nanoflakes all severely limit its development. Here, this work reports an efficient microwave exfoliation method that requires only 90s to exfoliate multilayered MXene into few-layer MXene (2–3 nm) with large-size (4～6 μm). Additionally, to enhance its capacitance and cycling stability, the exfoliated MXene was composited with graphene quantum dots, which shows a larger specific surface area, and importantly performs ultrahigh capacitance (343 F/g at a current density of 1 A/g) and excellent capacitance retention (100% after 10,000 cycles at a current density of 5 A/g). When using composite material as an anode, the assembled supercapacitor exhibits an excellent energy density of 35 Wh/kg at a power density of 384 W/kg with 107% capacitance retention after 10,000 cycles. Not only does this work provide an efficient approach to exfoliate MXene, but it also prepares a highly promising material for energy storage materials.