High-Yield Exfoliation of Large MXene with Flake Sizes over 10 μm Using Edge-Anchored Carbon Nanotubes

摘要

The exceptional properties of 2D transition metal carbides and nitrides(MXene) have led to numerous promising applications. However, theperformance of MXene is often dependent on the size of the flakes, andobtaining large-sized, high-quality MXene flakes remains challenging. Herein,a carbon nanotube (CNT)-assisted exfoliation strategy is introduced, whichsignificantly improves the yield of large-flake MXene while entirelytransforming the centrifugation residues into small-flake MXene, resulting inwaste-free synthesis of MXene. The average size of the obtained MXene flakescan reach over 10 and 0.7 μm for the two populations, respectively.Additionally, the capacitive performance of MXene can be greatly enhancedwith a small amount of CNTs. As a proof of concept, a planar interdigitalmicro-supercapacitor with heterogeneous layers assembled by large- andsmall-flake MXene simultaneously exhibits outstanding synergisticenhancement in volumetric capacitance (1072 F cm~(?3)) and energy density(53.5 mWh cm~(?3)). This CNT-assisted method provides explicit directions forachieving the ideal utilization of MXene, improving the yield of large flakeswhile making judicious use of waste, to meet specific application needs.