Khairul Bahiyah Md. Isa

Studies on Sodium Ion Conducting Gel Polymer Electrolytes

Sodium ion conducting gel polymer electrolyte (GPE) films consisting of polyvinylidenefluoride-co-hexafluoropropylene (PVdF-HFP) as a polymer host were prepared using the solution casting technique. Sodium trifluoromethane-sulfonate (NaCF3SO3) was used as an ionic salt and the mixture of ethylene carbonate (EC) and propylene carbonate (PC) as the solvent plasticizer. The GPE films were found to be stable up to temperature of 145 °C as shown by TGA analysis. The AC impedance study show that the optimum conductivity of 2.50 x 10-3 S cm-1 at room temperature is achieved for the film containing 20 wt.% of NaCF3SO3 salt. The temperature dependence of conductivity obeys VTF relation in the temperature range of 303 K to 373 K.

Ionic Transport in PMMA-NaCF3SO3 Gel Polymer Electrolyte

In this work, the polymethylmethacrylate (PMMA) based gel polymer electrolyte samples have been prepared by the solution casting technique. The composition range of the salt was from 3 wt% to 35 wt%. The ionic conductivity of the samples was measured using a.c. impedance technique. The highest room temperature conductivity was obtained from the sample containing 30 wt% of NaCF3SO3 salt, i.e. 5.31 x 10-3 S cm-1. The increase in the ionic conductivity with increasing salt concentrations is due to the increase in both concentration and mobility of charge carriers. The decrease in ionic conductivity at higher salt concentrations can be explained by aggregation of the ions, leading to the formation of ion-pair, thus decreasing the number of charge carriers and hence the ionic mobility. The conductivity-temperature dependence obeys the Arrhenius rule from which the activation energy was evaluated. The ionic transference number estimated by dc polarization method revealed that the conducting species are predominantly ions.

Ionic Conductivity, Morphology and Transference Number of Sodium Ion in PMMA Based Gel Polymer Electrolytes

The gel polymer electrolytes (GPEs) composed of polymethylmethacrylate (PMMA) with sodium trifluoromethanesulfonate (NaCF3SO3) salt dissolved in a binary mixture of ethylene carbonate (EC) and propylene carbonate (PC) organic solvents have been prepared by solution casting technique. The samples are prepared by varying the salt concentrations from 5 wt.% to 30 wt.%. Impedance spectroscopy measurement has been carried out to determine the ionic conductivity of the GPE samples. The sample containing 20 wt.% of NaCF3SO3 salt exhibits the highest room temperature ionic conductivity of 3.10 x 10-3 S cm-1. The conductivity of the GPEs has been found to depend on the salt concentration added to the sample though at higher salt concentration reveals decreasing in ionic conductivity due to ions association. The temperature dependence of conductivity from 303 K to 373 K is found to obey the Arrhenius rule. The ionic transference number, ti of GPEs has been estimated by DC polarization method and the value is found to be 0.95, 0.99, and 0.97 for the sample containing 5 wt.%, 20 wt.% and 30 wt.% respectively. This result is consistent with the conductivity studies.

Ionic Conductivity, Morphology and Transport Number of Lithium Ions in PMMA Based Gel Polymer Electrolytes

The gel polymer electrolytes (GPEs) composed of polymethylmethacrylate (PMMA) with lithium trifluoromethanesulfonate (LiCF3SO3) salt dissolved in a binary mixture of ethylene carbonate (EC) and propylene carbonate (PC) organic solvents have been prepared by the solution casting technique. The samples are prepared by varying the salt concentrations from 5 wt.% to 30 wt.%. Impedance spectroscopy measurement has been carried out to determine the ionic conductivity of the samples. The sample containing 25 wt.% of LiCF3SO3 salt exhibits the highest room temperature ionic conductivity of 2.56 x 10-3 S cm-1. The conductivity of the GPEs has been found to depend on the salt concentration added to the sample, while at higher salt concentration reveals a decrease in the ionic conductivity due to ions association. The temperature dependence of conductivity from 303 K to 373 K is found to obey the Arrhenius law. The ionic transference number, ti of GPEs has been estimated by the DC polarization method and the value is found to be 0.98, 0.93, and 0.97 for the sample containing 25 wt.%, 5 wt.% and 30 wt.% respectively. This result is consistent with the conductivity studies.

Studies of Ionic Conductivity and Dielectric Behavior in Polyacrylonitrile Based Solid Polymer Electrolytes

The solid polymer electrolyte films consisting of polyacrylonitrile (PAN) as the host polymer, lithium triflate (LiCF3SO3) and sodium triflate (NaCF3SO3) as dopant salts were prepared by the solution cast technique. The pure PAN film was prepared as a reference. The films were characterized using a.c. impedance spectroscopy. At room temperature, the highest conductivity for the sample from the (PAN+LiCF3SO3) system and the (PAN+NaCF3SO3) system is 3.04 x 10-4 Scm-1 and 7.13 x 10-4 Scm-1, respectively. The temperature dependence of ionic conductivity for the highest conducting film from both systems follows the Arrhenius equation in the temperature range of 303 K to 353 K. The frequency dependence of ionic conductivity, , complex permittivity, *, and complex electrical modulus, M* were studied at different temperatures. The ionic conductivity and the dielectric behavior are described in terms of ion diffusion and polarization.

Ionic Conductivity and Dielectric Properties of Plasticized Polyacrylonitrile Based Solid Polymer Electrolyte Films

The conducting polymer electrolyte films composed of polyacrylonitrile (PAN) as the host polymer, LiCF3SO3 and NaCF3SO3 as inorganic salts and ethylene carbonate (EC) as plasticizer were prepared by the solution cast technique. The conductivities of the films were characterized by impedance spectroscopy. On addition of more than 14 wt% of salt, the NaCF3SO3-containing PAN films exhibited higher ionic conductivity than the LiCF3SO3-containing PAN films. The values of the dielectric constant, εr and dielectric loss, εi increase as frequency decreases at room temperature. The temperature dependence of the conductivity obeys Arrhenius relation in the temperature range of 303 K to 353 K.

Comparison Studies of Blend and Unblend GPE Systems: Ionic Conductivity, Structural and Morphological Properties

Studies on comparison of blend and unblend PMMA-based gel polymer electrolytes containing LiClO4 salt with EC and PC as plasticizing solvent is reported. The GPE samples are prepared by varying the salt concentrations from 5 wt.% to 30 wt.%. At room temperature, PVdF-HFP/PMMA blend GPE exhibits the highest conductivity of 4.71 x 10-3 S cm-1 containing 25 wt.% of LiClO4 salt while the highest conductivity for unblend GPE is 3.34 x10-3 S cm-1 containing 20 wt.% of LiClO4 salt. The amorphous nature and morphological properties between LiClO4 salt, EC and PC in the blend and unblend GPE systems have been validated using XRD and FESEM analysis.

Morphological and Thermal Studies of Plasticized Poly (methyl methacrylate) Polymer Electrolyte Systems

In the present study, six systems of poly(methylmethacrylate) (PMMA)‐based polymer electrolyte films have been prepared using solution casting technique. They are; the pure PMMA system, the plasticized‐PMMA systems (PMMA+EC and PMMA+PC), the salted‐PMMA system (PMMA+LiBF4) and the plasticized‐salted PMMA systems (PMMA+EC+LiBF4 and PMMA+PC+LiBF4). The effect of adding the plasticizers and the salt to the PMMA based polymer electrolyte films on the morphology and thermal properties will be investigated using Fourier Transform Infrared Spectroscopy (FTIR), X‐Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Differential Scanning Calorimetry (DSC). The phase structure and the complexation for each system that has the highest conductivity are characterized using the XRD. The FTIR results confirmed the complexation has taken place between the plasticizers and the polymer, the salt and the polymer, and the plasticizers and the salt. These results are supported by SEM analysis. The glass transition te...