Two-Dimensional Layered Metallic VSe2 /SWCNTs/rGO Based Ternary Hybrid Materials for High Performance Energy Storage Applications.

In this work, the ternary hybrid structure VSe2 /SWCNTs/rGO is reported for supercapacitor applications. The ternary composite exhibits a high specific capacitance of 450 F g-1 in a symmetric cell configuration, with maximum energy density of 131.4 Wh kg-1 and power density of 27.49 kW kg-1 . The ternary hybrid also shows a cyclic stability of 91 % after 5000 cycles. Extensive density functional theory (DFT) simulations on the structure as well as on the electronic properties of the binary hybrid structure VSe2 /SWCNTs and the ternary hybrid structure VSe2 /SWCNTs/rGO have been carried out. Due to a synergic effect, there are enhanced density of states near the Fermi level and higher quantum capacitance for the hybrid ternary structure compared to VSe2 /SWCNTs, leading to higher energy and power density for VSe2 /SWCNTs/rGO, supporting our experimental observation. Computed diffusion energy barrier of electrolyte ions (K+ ) predicts that ions move faster in the ternary structure, providing higher charge storage performance.

The role of carbon nanotubes in enhanced charge storage performance of VSe2: experimental and theoretical insight from DFT simulations.

Herein, we report the hybrid structure of metallic VSe2 and multi-walled carbon nanotube (MWCNT) based hybrid materials for high performance energy storage and high power operation applications. The dominance of capacitive energy storage performance behaviour of VSe2/MWCNT hybrids is observed. A symmetric supercapacitor cell device fabricated using VSe2/80 mg MWCNT delivered a high energy density of 46.66 W h kg-1 and a maximum power density of 14.4 kW kg-1 with a stable cyclic operation of 87% after 5000 cycles in an aqueous electrolyte. Using density functional theory calculations we have presented structural and electronic properties of the hybrid VSe2/MWCNT structure. Enhanced states near the Fermi level and higher quantum capacitance for the hybrid structure contribute towards higher energy and power density for the nanotube/VSe2.