Various vanadium oxide nanostructures are currently drawn interest for the potential applications of Li batteries, super capacitors, and electrochromic display devices. In this article, the synthesis of V 2 O 5 nanotubes by hydrothermal method using 1-hexadecylamine (HDA) and PEO as a template and surface reactant were reported, respectively. The structural properties and electrochemical performances of these nanostructures were investigated for the application of Li batteries. Structure and morphology of the samples were investigated by XRD, FTIR, SEM, and TEM analysis. The battery with V 2 O 5 nanotubes electrode showed initial specific capacity of 185 mAhg -1 , whereas the PEO surfactant V 2 O 5 nanotubes exhibited 142 mAhg -1 . It was found that PEO surfactant V 2 O 5 nanotubes material showed less specific capacity at initial stages but better stability was exhibited at higher cycle numbers when compared to that of V 2 O 5 nanotubes. The cyclic performance of the PEO surfactant material seems to be improved with the role of polymeric component due to its surface reaction with V 2 O 5 nanotubes during the hydrothermal process.

No abstract

In this work, Li þ ion conducting polymer composite electrolyte films (PECs) were prepared based on poly (vinyl alcohol) (PVA), lithium hexafluoro arsenate (LiAsF 6 ), and ceramic filler TiO 2 using solution cast technique. The XRD and FTIR spectra were used to determine the complexation of the PVA polymer with LiAsF 6 salt. The ionic conductivities of the (PVA þ LiAsF 6 ) and (PVA þ LiAsF 6 þ TiO 2 ) films have been determined by the A.C. impedance measurements in the temperature range 320-440 K. The maximum conductivity was found to be 5.10 3 10 24 S cm 21 for PVA:LiAsF 6 (75:25) þ 5 wt% TiO 2 polymer composite film at 320 K. The calculation of Li þ ion transference number was carried out by the combination of A.C. impedance and D.C. polarization methods and is found to be 0.52 for PVA:LiAsF 6 (75:25) þ 5 wt% TiO 2 film. Optical properties such as direct energy gap, indirect energy gap, and optical absorption edge values were investigated in pure PVA and salt complexed PVA films from their optical absorption spectra in the wavelength range of 200-600 nm. The absorption edge was found at 5.76 eV for undoped film, while it is observed at 4.87 and 4.70 eV for 20 and 25 wt% LiAsF 6 doped films, respectively. The direct band gaps for these undoped and salt doped PVA films were found to be 5.40, 5.12, and 4.87 eV, respectively, whereas the indirect band gaps were determined as 4. 75, 4.45, and 4.30 eV. POLYM. ENG. SCI.,