A novel high-entropy MXene Ti1.1V1.2Cr0.8Nb1.0Mo0.9C4Tx for high-performance supercapacitor

Both MXenes and high-entropy ceramics are booming material families. The rich surface functional groups and elemental controllability of MXenes, as well as the rich composition space of high-entropy ceramics provide these materials unexpected chemical properties, and thus they have great potential in energy storage. Herein, we successfully synthesized a novel high-entropy MXene (HE-MXene), Ti1.1V1.2Cr0.8Nb1.0Mo0.9C4Tx for the first time. The aberration-corrected scanning transmission electron microscopy, density functional theory calculation, and super energy-dispersive X-ray spectroscopy together demonstrate that the five transition metals are uniformly dispersed in one MX slab in the form of solid solutions. The Ti1.1V1.2Cr0.8Nb1.0Mo0.9C4Tx exhibits high capacity as a supercapacitor electrode with a gravimetric capacitance of 284.6 F g−1 at a current density of 1 A g−1 and also shows outstanding stability. This work proves the existence of M5X4Tx HE-MXene and further adds a new member to the MXene family, providing support for its application in other fields.