Vanadium telluride nanoparticles on MWCNTs prepared by successive ionic layer adsorption and reaction for solid-state supercapacitor

Abstract

Anchoring of vanadium telluride (VxTey) nanoparticles onto the exterior layer of multi-walled carbon nanotubes (MWCNTs) has been successfully employed at room temperature (300 K) as first report by using successive ionic layer adsorption and reaction (SILAR) to yield VxTey/MWCNTs surface architecture. Mutualistic contribution from ion insertion/extraction introduced non-stoichiometric vanadium telluride with electric double-layer involved MWCNTs have been unified to enrich excellent electrochemical performance. Three-electrode system configured VxTey/MWCNTs electrode yields 16-fold enhancement in specific capacitance compared to the bare MWCNTs electrode. Achieved performance forced us to construct flexible solid-state supercapacitor device (FSS-SC). Symmetric electrode embedded with PVA-LiClO4 gel mediator harvests remarkable 2 V voltage window to gain 34.5 Wh/kg energy density and 0.7 kW/kg power density. Cycling over 10000 replications confirms the pronounced (82.5 %) stability of designed device and growing LED enables practical evidence; demonstrating its capacity as efficient energy storage device. Correlated density functional theory (DFT) has been manifested to confirm synergistic interactions between the VxTey and MWCNTs, and a corresponding enhancement in the electron density at the Fermi level of VxTey/MWCNTs describes the insight origin for enhanced supercapacitance.