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Choudhary A.,Government V Y T Pg Autonomous College | Sahu Y.K.,Government V Y T Pg Autonomous College | Oudhia A.,Computational Nanoionics Research Laboratory | Verma M.L.,Government V Y T Pg Autonomous College
Advanced Science Letters | Year: 2015

Here we present an ab-initio study of structural and electronic properties of ZnO molecules optimized in two different geometries viz. 3D ZnO-Cage Like structure and a planer ZnO nanoribbon (ZNR) structure. The whole environment was set in local density approximation correlation function (LDA) under density functional theory (DFT). A noticeable difference in the band gap and consequent electronic properties of the ZnO-Cage like structure with respect to ZNR is observed. The study reveals new possibilities for the fabrication of ZnO nanostructures with controlled electronic properties through shape dependent structural reconstructions. © 2015 American Scientific Publishers. All rights reserved. Source

Singh N.K.,Shri Shankaracharya Institute of Engineering and Technology | Verma M.L.,Computational Nanoionics Research Laboratory | Minakshi M.,Murdoch University
Bulletin of Materials Science | Year: 2015

Physical and electrochemical properties of polyethylene oxide (PEO)-based nanocomposite solid polymer electrolytes (NPEs) were investigated for symmetric capacitor applications. Nanosize fillers, i.e., Al2O3 and SiO2 incorporated polymer electrolyte exhibited higher ionic conductivity than those with filler-free composites. The composites have been synthesized by the completely dry (solution-free) hot-press method. The addition of filler in fractional amount to the solid polymermatrix at room temperature further enhances the ionic conductivity. Nature of the NPEs were studied using X-ray diffraction and energy-dispersive spectra analyses. Thermal stability of the resulting electrolyte was analysed by thermogravimetric analysis and differential scanning calorimetric studies. Morphology changes occurred during the addition of fillers was evidenced by scanning electronic microscope images. Solid polymer electrolytes exhibiting these parameters was found to be suitable for solid state capacitors. The results obtained from the electrolytes with an optimum compositions (PEO70AgI30)93(Al2O3)7 and (PEO70AgI30)95(SiO2)5 used in the (PEO70AgI30)70(AC)30 electrodes for symmetric capacitor applications and their performances were analysed by impedance spectroscopic, Bode plot, cyclic voltammetry, discharge characteristics and leakage current profile. © Indian Academy of Sciences. Source

Rao B.K.,Computational Nanoionics Research Laboratory | Verma M.L.,Computational Nanoionics Research Laboratory
Chemical Physics | Year: 2016

Inclusion of the space charge depolarization in the model to calculate transport properties of a nano-composite material is investigated. Specifically, the effect of diffusion current density; displacement current density; ohmic current density and excess charge current density are included under an open circuit condition. The proposed model takes into account of the excess charge produced during the space charge polarization, and may be applied to any ionic material. © 2016 Elsevier B.V. Source

Verma M.L.,Computational Nanoionics Research Laboratory | Sahu H.D.,Computational Nanoionics Research Laboratory
Ionics | Year: 2015

Solid nanocomposite polymer electrolytes based on polyethylene oxide (PEO), AgNO3 as salt, and nanosized Fe2O3 (less than 50 nm size) as filler are prepared by hot press method. In (100-x) PEO:xAgNO3 system (where x = 5 ≤ x ≤ 50 wt%), the solid polymer electrolyte 90PEO:10AgNO3 gives highest ionic conductivity. This composition is further used as host matrix and Fe2O3 as filler for the preparation of solid nanocomposite polymer electrolytes (100-x) (90PEO:10AgNO3):xFe2O3 (where x = 5 ≤ x ≤ 30 wt%). The real impedance (Z') and imaginary impedance (Z") of the samples are analysed using LCR meter. The maximum ionic conductivity is observed for 10 wt% of filler Fe2O3. The optimum conducting composition 90(90PEO:10AgNO3):10Fe2O3 is used for further study. The dielectric response of the samples is analysed using dielectric constant (ε'), dielectric loss (ε"), loss tangent (tanδ), and real and imaginary part of electric modulus (M' and M"). The ionic conductivity and dielectric response of the solid nanocomposite polymer electrolytes are studied within the frequency range of 100 Hz–5 MHz and within the temperature range of 300–323 K. It is observed that the dielectric constant rises sharply towards low frequencies due to electrode polarization effects. The maxima of the loss tangent (tan δ) shift towards higher frequencies with increasing temperature. The enhancement in ionic conductivity is observed when nanosized Fe2O3 filler is added into the solid polymer electrolyte. © 2015, Springer-Verlag Berlin Heidelberg. Source

Rao B.K.,Computational Nanoionics Research Laboratory | Verma M.L.,Computational Nanoionics Research Laboratory
Ionics | Year: 2015

The analysis of ionic mobility of Ag+ ions in the nano-composite material is performed. The material is space charge polarized initially by applying a dc field ~0.5 V. The depolarization potential is recorded at various isothermal conditions in the temperature range of 300–535 K. By considering open circuit condition, drift and trapped ionic mobility are analyzed and the results are compared with the ionic mobility measured by conventional transient ionic current (TIC) and experimental techniques in the same temperature range. © 2014, Springer-Verlag Berlin Heidelberg. Source

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