Heterostructured Metallic 1T-VSe 2 /Ti 3 C 2 T x MXene Nanosheets for Energy Storage

MXene-based hybrid materials have been expedited extensively for supercapacitors and energy storage applications. In this work, we have grown the metallic VSe 2 layered material on MXene sheets to achieve enhanced energy storage performance. The VSe 2 /MXene heterostructures showed improved energy storage performance with a specific capacitance of 144 F/g at a specific current of 1 A/g and a cycling life of 92.8% after 5000 charge–discharge cycles in a two-electrode symmetric configuration. Further, we have presented extensive density functional theory simulations to study the bonding interaction and electronic properties of VSe 2 and its hybrid VSe 2 /MXene. The enhanced states near the Fermi level, superior quantum capacitance, and lower diffusion barrier of hybrid VSe 2 /MXene over the VSe 2 support the improved charge storage and better capacitive behavior of the hybrid, as indicated by experimental observations. The interaction between VSe 2 and the MXene is due to the electronic charge transfer from the Ti 3d orbital of the MXene to V 3d orbital of VSe 2, in addition to weak van der Waals forces. An asymmetric supercapacitor was also constructed to exploit the high energy storage performance of the VSe 2 /MXene electrode. Further, the VSe 2 /MXene//MoS 2 /MWCNT asymmetric electrode assembly delivered an energy density of 42 W h/kg at power density of 2316 W/kg with a capacitance retention of 90% after 5000 charge–discharge cycles.