A Novel Solid-Solution MXene with High Gravimetric Capacitance

MXenesMXene are a recently discovered family of two-dimensional (2D) early transition metalMetals carbides or carbon-nitrides that have shown many attractive properties and hold great promise for energy storage and other applications. Although many MXenesMXene have been synthesized, most studies have focused on Ti3C2Tx or other single-transition metalMetals MXenesMXene. In addition, studies on the electrochemical properties of solid-solution MXenesMXene are scarce. Herein, a new vanadium-titaniumTitanium double transition metalMetals MAXMAX phase and its corresponding MXeneMXene were successfully synthesized. By combining X-ray diffractionX-ray diffraction (XRD), X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, and scanning transmission electron microscopy, we determined the structureStructure and phase purity of vanadium-titaniumTitanium double transition metalMetals MXeneMXene. In addition, this MXeneMXene exhibits excellent gravimetric capacitance and long-lasting stability when applied as an electrode for the supercapacitorSupercapacitors. This work not only expands the MXenesMXene family, but also provides a strategy for the preparationPreparation of solid-solution MXenesMXene.