Study of structural and electrochemical properties of tungsten-doped V₂O₅ nanostructures for solid state energy storage applications

Vanadium-based nanostructures are extensively studied for energy storage applications due to their excellent charge transfer capability. However, low electrical conductivity limits their commercial application. This can be overcome by suitably doping cations into the crystal lattice of vanadium pentoxide (V₂O₅) without inducing any phase change within the material. Herein, we report the synthesis of tungsten (W)-doped vanadium pentoxide (W-V₂O₅) nanosheets with enhanced conductivity through a low temperature wet chemical route for a range of W doping in V₂O₅ from 0.5 to 1.2 at. %. The successful incorporation of tungsten into the V₂O₅ lattice was confirmed from the X-ray Diffraction results and Energy Dispersive Spectroscopy. A symmetric two-electrode system was used to evaluate the electrochemical properties. The system consists of W-V₂O₅ coated carbon fibrous sheet as the active electrode, grafoil current collectors and Nafion conducting polymer as the electrolyte. A highest specific capacitance of 104 F/g was achieved at 0.5 at. % of tungsten doping. This novel configuration with solid state electrolyte shows reduced charge transfer resistance due to enhanced surface reactivity of W-V₂O₅ nanoparticles and hence, promising electrode material for energy storage applications.