Heterostructured Metallic 1T-VSe₂/Ti₃C₂T_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 VSe2 layered material on MXene sheets to achieve enhanced energy storage performance. The VSe2/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 VSe2 and its hybrid VSe2/MXene. The enhanced states near the Fermi level, superior quantum capacitance, and lower diffusion barrier of hybrid VSe2/MXene over the VSe2 support the improved charge storage and better capacitive behavior of the hybrid, as indicated by experimental observations. The interaction between VSe2 and the MXene is due to the electronic charge transfer from the Ti 3d orbital of the MXene to V 3d orbital of VSe2, in addition to weak van der Waals forces. An asymmetric supercapacitor was also constructed to exploit the high energy storage performance of the VSe2/MXene electrode. Further, the VSe2/MXene//MoS2/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.