Effect of Li-ion doping on structural, optical and electrochemical properties of V2O5

In the present study, lithium doped vanadium pentoxide LixV2O5 (0.2 <= x <= 0.8) specimens have been prepared by the solid-state synthesis method, which possesses an ionic and electronic conducting nature. Lithium incorporates vanadium pentoxide to increase electrical conductivity as well as to enhance energy storage capacity. The undoped V2O5 samples show orthorhombic structures, which are slightly tilted towards monoclinic due to lithium doping. These structural and compositional studies have been carried out using X-ray diffraction spectra and X-ray photoelectron spectroscopy. The stretching and vibrational modes of prepared samples are obtained by Fourier Transform Infrared Spectrometer. The significant shifting of optical absorption is observed and hence the optical energy band decreases from 3.37 to 2.44 eV for the present specimens. Electrochemical analysis in the potential window of -0.5 to 0.5 V (scan rate of 5 mV/s) with 2 M KCl electrolyte solution is conducted to get maximum specific capacitance of 529 Fg(-1) for Li0.2V1.8O4.6 specimen. The first and fifth cycles of Cyclic Voltammetry suggest that the charging and discharging of LixV2O5 are in accordance with doped component proportion. The dielectric parameters have been recorded with a frequency response of 10 Hz to 1 MHz. The ac conductivity data has been interpreted by Jonscher's power law.