S. L. Agrawal

Dielectric and Ion Transport Studies in [PVA: LiC2H3O2]: Li2Fe5O8 Polymer Nanocomposite Electrolyte System

The present work deals with the findings on optical and ion transport behavior in a ferrite-doped polymer nanocomposite electrolyte system, namely, [(100 − x) PVA + xLiC2H3O2]: yLiFe5O8. This polymer electrolyte system has been characterized by SEM, DSC, IR and C-V measurements. The addition of filler seems to disturb the crystalline nature of the host matrix while the doping of salt shows a similar structure, but with a separate entity in SEM images. DSC studies reflect the interaction of the salt/filler with polymer with a change in morphology of the composite system. These results are well-corroborated by IR data. The effect of salt or filler in the enhancement of the a.c. conductivity of nanocomposite polymer electrolyte (NCPE) as well as dielectric relaxation behavior has been investigated with the help of impedance spectroscopy data. The a.c. conductivity of nanocomposite polymer electrolytes is seen to be best described by the universal power law.

DMA and conductivity studies in PVA:NH 4 SCN:DMSO:MWNT nanocomposite polymer dried gel electrolytes

This paper deals with findings on dynamic mechanical analysis (DMA) and ion-conduction behavior of MWNTs (multiwall carbon nanotubes) doped PVA:NH4SCN:DMSO dried gel electrolyte system prepared for four filler concentrations (2, 4, 6 & 8 wt%) by solution cast technique. XRD measurements reveal enhancement in amorphous behavior of composite gel electrolyte upon incorporation of filler particles. Better mechanical stability is noticed in the composite system upon dispersal of MWNT along with presence of dynamic Tg during DMA measurements. Enhancement in ionic conductivity has been noticed with an optimum value of 4.5 × 10-3 Scm-1 for 6 wt% MWNTs filled composite electrolyte. Composite system exhibits combination of Arrhenius and Vogel-Tammam-Fulcher (VTF) behavior in temperature dependent conductivity study. The a.c. conductivity response seems to follow universal power law.

Structural and thermal studies of [PVA–LiAc] : TiO2 polymer nanocomposite system

Nanocomposite polymer electrolyte consisting of polyvinyl alcohol (PVA) and lithium acetate with TiO2 filler has been synthesised by combination of solution cast technique and sol–gel process. The composite electrolyte films were characterised by different experimental techniques. The average particle size of composite electrolytes lies between 25 and 30 nm. System is essentially ionic with maximum conductivity of polymer electrolyte 90[80PVA–20LiAc]:10TiO2 (∼4.5 × 10−6 S cm−1) at room temperature.

Study of structural and dielectric behaviour on carbon nano tube dispersed {xPVF: (1 − x)CH3COONH4} electrolyte

In the present work, improvement in ion transport property of polyvinyl formal (PVF)-based nanocomposite polymer electrolytes has been studied upon dispersal of multiwall carbon nanotube (MWCNT) filler. Nanocomposite polymer electrolyte (NCPE) films of xPVF: (1 − x)CH3COONH4 (ammonium acetate) were prepared by solution cast technique. The formation of nanocomposite has been ascertained by X-ray diffraction (XRD) pattern, which also shows that doping of salt increases amorphousness through polymer salt complexation. Changes in surface morphology have been observed in optical microscopy and Scanning Electron Microscopic (SEM) images. Variation of dielectric constant, dielectric loss, tangent loss and modulus spectra with the change in frequency and temperature were studied with the aid of impedance spectroscopy.

Performance of ferrite fillers on electrical behavior of polymer nanocomposite electrolyte

Dispersal of nanofillers in polymer electrolytes have shown to improve the ionic properties of Polyethylene oxide (PEO)-based polymer electrolytes in recent times. The effects of different nanoferrite fillers (i.e., Al–Zn ferrite, Mg–Zn ferrite, and Zn ferrite) on the electrical transport properties have been studied here on the composite polymer electrolyte system. The interaction of salt/filler with electrolyte has been investigated by XRD studies. SEM image and infrared spectral studies give an indication of nanocomposite formation. In conductivity studies, all electrolyte systems are seen to follow universal power law. Composition dependence (with ferrite filler) gives the maximum conductivity in [93PEO–7NH4SCN]: X ferrite (where X = 2% in Al–Zn ferrite, 1% Mg–Zn ferrite, and 1% Zn ferrite) system.