Synthesis and Study of PVA Based Gel Electrolyte

Bulletin of Materials Science, 2004

An attempt has been made in the present work to prepare polyvinyl alcohol (PVA) based proton conducting gel electrolytes in ammonium thiocyanate (NH 4 SCN) solution and characterize them. DSC studies affirm the formation of gels along with the presence of partial complexes. The cole-cole plots exhibit maximum ionic conductivity (2⋅ ⋅58 × 10 -3 S cm -1 ) for gel samples containing 6 wt% of PVA. The conductivity of gel electrolytes exhibit liquid like nature at low polymer concentrations while the behaviour is seen to be affected by the formation of PVA-NH 4 SCN complexes upon increase in polymer content beyond 5 wt%. Temperature dependence of ionic conductivity exhibits VTF behaviour.

PVA gel electrolyte with different concentration of PVA (0.5, 1 ,1.5, 2 ,2.5 by weight) in KSCN+DMSO electrolyte has been prepared by simple technique and characterized by X-RD and measuring d.c. conductivity electrical conductivity as a function of temperature in the range 00to 1000c . Variation of conductivity of gel electrolyte with loading concentration of PVA has also been studied .It has been observed that all gel sample are amorphous in nature with shifting a broad peak. As loading of PVA in 0.2 M electrolyte of KSCN+DMSO increases conductivity decreases. But conductivity is found to be increases with increases in temperature for all sample consisting VTF and Arrhenius behavior.

An attempt has been made in the present work to combine gel and composite polymer electrolyte routes together to form a composite polymeric gel electrolyte that is expected to possess high ionic conductivity with good mechanical integrity. Polyethylene glycol (PEG) based composite gel electrolytes using polyvinyl alcohol (PVA) as guest polymer have been synthesized with 1 molar solution of ammonium thiocyanate (NH4SCN) in dimethyl sulphoxide (DMSO) and electrically characterized. The ionic conductivity measurements indicate that PEG : PVA : NH4SCN-based composite gel electrolytes are superior (σmax = 5.7 × 10 −2 S cm −1 ) to pristine electrolytes (PEG : NH4SCN system) and conductivity variation with filler concentration remains within an order of magnitude. The observed conductivity maxima have been correlated to PEG : PVA : NH4SCNand PVA : NH4SCN-type complexes. Temperature dependence of conductivity profiles exhibits Arrhenius behaviour in low temperature regime followed by VTF character at higher temperature.

Ionics, 2013

Polyvinyl alcohol (PVA) complexes with different compositions of ammonium acetate (AA) are prepared by solution cast technique. Polyvinyl alcohol crystallinity decreased with increasing ammonium acetate salt content. Molecular weight and density of polyvinyl alcohol complex increased with the addition of ammonium acetate salt. The ammonium acetate salt addition resulted in plasticization and hence decreased glass transition temperature (T g) as well as hardness number (HV). 80PVA:20AA presented maximum conductivity (σ=1.3×10 −7 S cm −1 at 303 K) with minimum activation energy (E a) 0.151 eV below the T g. The proton transport number determined using EMF method found ≈0.98 for polymer complex with ammonium acetate content >15 mol%. The complex impedance is measured as a function of frequency, temperature, relative humidity, and hydrogen partial pressure. Enhanced bulk conductivity with increased H 2 partial pressure and relative humidity suggested H + mobility within complex polymer electrolyte.

International Journal of Chemtech Research, 2014

The present study focuses on characterizing PAN+NH 4 I proton conducting polymer electrolyte films prepared by solution casting technique.Two plasticizers, ethylene carbonate (EC) and dimethyl formamide (DMF) were used as solvents in this system. These prepared films can be characterized by using FTIR, XRD and DC conductivity studies. The FTIR spectroscopic study illustrates the detailed interaction of PAN with NH 4 I salt. The XRD spectroscopic patterns of all the prepared polymer electrolyte films disclose the amorphous nature of the films and it also clearly establishes the complexation of the NH 4 I salt with the polymer PAN. The variation of conductivity with salt concentrations of 10 wt% to 40 wt% was studied. The sample containing 30 wt% of NH 4 I exhibited the highest conductivity of 1.49x10-4 S cm-1 at room temperature (303K) and 2.46x10-4 S cm-1 at 373K.The conductivity-temperature dependence of polymer electrolyte films obeys Arrhenius behaviour with activation energy in the range of 0.07 eV to 0.25 eV. Very low value of E a suggests that proton (H +) conduction is superficial in this gel polymer electrolyte of optimum composition.

Solid State Ionics, 2003

The effect of donor number of solvent on the conductivity behaviour of gel electrolytes has been studied. Liquid electrolytes were prepared by dissolving salicylic acid in solvents based on ethylene carbonate (EC), propylene carbonate (PC) and dimethylformamide (DMF) with different donor number and dielectric constant values. Three different polymers, polymethylmethacrylate (PMMA), polyacrylonitrile (PAN) and polyethylene oxide (PEO), were used as the gelling polymer. The conductivity of polymer gel electrolytes has been found to be higher than the corresponding liquid electrolytes, i.e. r (gel)>r (liquid). This has been explained to be due to an increase in carrier concentration by the dissociation of undissociated salicylic acid/ion aggregates present in the electrolytes with the addition of polymer. However, the relative increase in conductivity observed with the addition of different gelling polymers has been found to depend upon the donor number of the solvent used.

AIP Conference Proceedings, 2017

Gel polymer electrolytes (GPEs) have captured great attention because of their unique properties such as good mechanical stability, high flexibility and high conductivity approachable to that of the liquid electrolytes. In this work, we have prepared sodium ion conducting gel polymer electrolyte (GPE) films consisting of polyvinylidenefluoride-cohexafluoropropylene (PVdF-HFP) as a polymer host using the solution casting technique. Sodium trifluoromethanesulfonate (NaCF 3 SO 3) was used as an ionic salt and the mixture of ethylene carbonate (EC) and propylene carbonate (PC) as a plasticizing solvent. Impedance spectroscopy measurements were carried out to determine the ionic conductivity of the GPE films. The sample containing 20 wt.% of NaCF 3 SO 3 salt exhibits the highest room temperature ionic conductivity of 2.50 x 10-3 S cm-1. The conductivity of the GPE films was found to depend on the salt concentration that added to the films. The ionic and cationic transference numbers of GPE films were estimated by DC polarization and the combination of AC and DC polarization method, respectively. The results had shown that both ionic and cationic transference numbers are consistent with the conductivity studies. The electrochemical stability of the GPE films was tested using linear sweep voltammetry (LSV) and the value of working voltage range appears to be high enough to be used as an electrolyte in sodium batteries. The cyclic voltammetry (CV) studies confirmed the sodium ion conduction in the GPE films.

Journal of Applied Electrochemistry, 2009

Polymer gel electrolytes synthesized by dispersing nano size fumed silica in polymer gel electrolytes containing polymethylmethacrylate (PMMA), orthohydroxy benzoic acid (o-OHBA) and dimethylacetamide (DMA) have been studied by complex impedance spectroscopy, viscosity and pH measurements. The addition of acid, polymer and fumed silica has been found to result in an increase in conductivity and viscosity of gel electrolytes and gels with conductivity higher than the corresponding liquid electrolytes have been obtained. Nano dispersed polymer gel electrolytes show conductivity 2.95 9 10-4 S cm-1 and viscosity 1.74 9 10 4 cP at 25°C. Two maxima observed in the variation of conductivity of nano dispersed gels with fumed silica concentration have been assigned to the enhanced dissociation of weak acid and the formation of a high conducting interfacial region between fumed silica and gel electrolyte, respectively, which has also been supported by pH and viscosity studies. The small increase in conductivity of nano dispersed gels over the 20-100°C temperature range and its constant value with time is suitable for devices.

Physica B-condensed Matter, 2005

The polymer electrolytes composed of poly (vinyl acetate) (PVAc) with various stoichiometric ratios of ammonium thiocyanate (NH4SCN) salt have been prepared by solution casting method. The polymer–salt complex formation and the polymer–proton interactions have been analysed by FT-IR spectroscopy. The conductivity and dielectric measurements are carried out on these films as a function of frequency at various temperatures. The complex impedance spectroscopy results reveal that the high-frequency semicircle is due to the bulk effect of the material. The conductivity is found to increase in the order of 10−8–10−4 S cm−1 at 303 K with the increase in salt concentration. The ionic transference number of mobile ions has been estimated by Wagner's polarization method and the results reveal that the conducting species are predominantly due to ions. The transient ionic current (TIC) measurement technique has been used to detect the type of mobile species and to evaluate their mobilities. The dielectric spectra show the low-frequency dispersion, which is due to the space charge effects arising from the electrodes.

Polymer Bulletin, 2017

Conducting polymer electrolytes based on poly(vinyl alcohol) (PVA) as a host polymer matrix and polyionic liquid (PIL) hydrophilic/hydrophobic were prepared by solution casting technique and characterized by FTIR, scanning electron microscope (SEM), mechanical, conductivity, dielectric spectroscopy and thermogravimetric analysis. It was found that the presence of PIL affected positively both mechanical and electrical properties of the polymer electrolytes. Polymer electrolytes with PIL-dispersion give the best tensile strength compared to those with PIL-solid. From the results of mechanical properties, it is concluded that PILdispersion can act as a plasticizer, whereas PIL-solid can act as traditional filler. The addition of PIL-dispersion significantly increased the permittivity e 0 and dielectric loss e 00 and improved the ionic conductivity of the polymer electrolytes compared to PIL-solid. The ionic conductivity of these polymer electrolytes is greatly increased with doping of PIL-dispersion owing to their strong plasticizing effect. The data of electric modulus M 00 are analyzed in terms of Havriliak-Negami function through three relaxation mechanisms. In the temperature range from 50 to 150°C, three distinct relaxation processes, namely a, ab and b relaxations were detected in all samples. Polymer electrolytes based on hydrophilic PIL showing ionic conductivities in the range of 10-9-10-5 S/cm are good candidates in construction of electrochemical cells, whereas those based on hydrophobic PIL are suitable for use in liquid membranes.