Ionic Conduction in Different Hydrated V2O5 Film

Abstract

Because of the layered structure of vanadium pentoxide films (V2O5), approved by XRD measurement, sensitized from different hydrated V2O5 center dot nH(2)O sols, demonstrated anisotropic conductivities in current voltage (I-V) measurement. Conductivity values, originated from electronic and ionic conductions, differed provided that measurements were performed in a direction parallel to the ribbons rather than perpendicular to them. The overall electrical conductivity of V2O5 nH(2)O sols mainly depended on the hydration state n and the amount of reduced V4+ ions in which n was determined around 4-6 [1] from the basal distance (17.6 angstrom) through XRD measurement while V4+ ions were determined through FTIR analysis. Electronic conduction prevailed in dehydrated V2O5 0.5H(2)O sols whereas non-stoichiometric vanadium pentoxide was a mixed-valence compound and its electronic properties arised from electron hopping between V4+ and V5+ ions so-called small polaron model. Indeed, reduction/oxidation peaks in lithium (Li+) intercalation by cyclic voltammograms (CV) indicated the V4+ and V5+ ions in V2O5 sols. Temperature dependent I-V analysis showed Arheniuss type activation energy, EA, and located in between 0.3-0.5 eV; proposing ionic conduction rather than electronic conduction, specifically proton diffusion in V2O5 film. Indeed, hydration state greater than 0.5 predicted ionic conduction [1].