Ni‐Doped VS ₄ Nanostructure for Energy Storage and Hydrogen Evolution Reaction

Transition metals and chalcogenides are the recently trending materials because they form a layered structure that provides a high surface‐to‐volume ratio. Energy storage from renewable sources requires a fast energy storage device, and for the production of hydrogen, it necessitates a suitable catalyst that operates efficiently over an extended period. So, in this paper, a bifunctional material, VS 2 , is prepared using a one‐pot hydrothermal technique. To enhance both energy storage performance and catalytic performance, Ni is introduced as a dopant. From X‐ray diffraction (XRD), it is found that after Ni incorporation, phase transformation occurs from Hexagonal VS 2 to monoclinic VS 4 . The field‐emission scanning electron microscopy shows the nanosheet‐like structure. The rod‐like structure is observed using transmission electron microscope. The cyclic voltammetry curve was further evaluated for the diffusive and capacitive contributions. In the three‐electrode configuration, the material demonstrates supercapacitive behavior dominated by electric double‐layer capacitance‐type surface‐controlled kinetics, with only 32% diffusion contribution. However, in the symmetric device, the diffusion‐controlled component increases markedly to 84.5%, indicating that the full cell operates through a predominantly battery‐type hybrid capacitor mechanism. The VS 4 ‐Ni (1%) material exhibits good catalytic activity, requiring a potential of 511.26 mV to achieve a current density of 10 mA/cm 2 . Additionally, the material exhibits optoelectronic properties as a visible light detector.