Nano-crystal V[sub 2]O[sub 5]nH[sub 2]O sol-gel films made by dip coating

Abstract

Vanadium pentoxide (V2O5) sols were formed through a reaction of V2O5 powder with hydrogen peroxide (H2O2); the solution evolves in time, beginning from diperoxo species, decavanadic acid spedies at intermediate step and finally polymerization of V2O5nH2O sols. From the sols, V2O5 thin films were succesfully fabricated on indium-tin-oxide (ITO) coated and corning glass substrates by sol-gel dip coating method. X-ray diffraction pattern of the films at hand exhibited a series of (00l) peaks that confirmed both some preferred orientation of a layered structure in one dimension stacking of ribbons perpendicular to the substrate and ability of employed method to produce nano crystal of V2O5nH2O sol-gel films. The basal distance, d, (increased with an amount of water in the sols in steps of 2.8 Å, attributed van der Walls water molucule diameter), was determined as 10.6-17.2 Å that corresponded n in between 2-6. On the other hand, the average particle sized, D, of the precipitated nanocrystals were calculated through Sherrer’s formula and determined around 15-28 nm that consisted with AFM and SEM analysis. The electrochemical studies by cyclic voltametry showed the Li+ intercalation capacity, reversibility and stability. Finally, the simultaneous TG and DTA on the as prepared films indicated two stage mass loss.