Investigate Salts type and concentration on the conductivity of Polymer Electrolyte

Polymer electrolytes systems compose of (PEO+KI+I2) and (PEO+RbI+I2) with different concentration, and a fixed amount of ethylene carbonate (EC) and propylene carbonate (PC) over temperatures range 293-343 K prepared by solution cast method. The conductivity and dielectric constant of the gel electrolytes were studied. The conductivity of the electrolytes Ss & Hs increases steadily with increased concentration of salt KI and RbI. The higher value of conductivity of (4.7 10-3 @ RT S.cm-1) for S5 electrolyte which contains (KI 50%). Whereas the maximum amount of conductivity of (5.4 10³ @RT S.cm⁻ˡ) for H5 electrolyte which contains (RbI 50%) the ionic conductivity depends on the ionic radii of the migrating species (cation K⁺, Rb⁺) effect on it. As the temperature increase, the number of free ions also increases, thus increases the diffusion of ions through their free volume of the polymer. The dielectric constant decrease at higher frequencies due to the inability of dipoles to align quickly with the change of applied field. The dielectric constant proportional positively with variation temperature causes an increase in the dielectric constant. The higher the value of (εr), the better is the electrical conductivity.

Conductivity and Dielectric Studies of Lithium Trifluoromethanesulfonate Doped Polyethylene Oxide-Graphene Oxide Blend Based Electrolytes

Series of polymer blend consisting of polyethylene oxide (PEO) and graphene oxide (GO) as co-host polymer were prepared using solution cast method. The most amorphous PEO-GO blend was obtained using 90 wt.% of PEO and 10 wt.% of GO as recorded by X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FTIR) analysis proved the interaction between PEO, GO, lithium trifluoromethanesulfonate (LiCF3SO3), and ethylene sulfite (ES). Incorporation of 25 wt.% LiCF3SO3into the PEO-GO blend increases the conductivity to3.84±0.83×10-6 S cm−1. The conductivity starts to decrease when more than 25 wt.% salt is doped into the polymer blend. The addition of 1 wt.% ES into the polymer electrolyte has increased the conductivity to1.73±0.05×10-5 S cm−1. Dielectric studies show that all the electrolytes obey non-Debye behavior.

Influence of Evaporation Temperature on the Morphology, Polymorph and Mechanical Properties of Poly(vinylidene fluoride) Solution-Cast Membranes

In this study, PVDF membranes were prepared by solution-cast method. The effects of evaporation temperature on the morphology, polymorph and mechanical properties of such prepared membranes were studied. It was found that perfect spherulites were observed in the solution-cast membranes. FESEM photomicrographs of the membranes showed dense structure. PVDF mainly crystallized into α phase. In the solution-cast process, the spherulite size increased as evaporation temperature was increased from 120 °C to 150 °C, when the evaporation temperature was 165 °C, spherulite size decreased. And the tensile strength increased with the decrease in spherulite size.

Positron Annihilation Characterization of TiO2 Doped Polystyrene

TiO2 doped polystyrene thin films fabricated by solution cast method. The effect of dopant concentrations has been studied for the structural, morphological, optical and defects properties. The XRD results revealed that the degree of crystallinity remains largely invariant due to the presence of the polymer. Interesting results have been obtained from optical measurement which depicted that there is increase in UV-shielding efficiency with the increase in the dopant concentration as the absorbance was found to be maximum in case of UV region. Surface morphology of the films shows a rod like structure for 0.25 wt% of TiO2, while for higher concentrations the TiO2 clusters were obtained. The positron lifetime results reveal that the free volume hole concentration decreased with the increase in TiO2 concentration as intensity of o-positronium decreases with the increase in concentration of TiO2 doping.

Desorption Studies on Hydrogenated Single Walled Carbon Nanotubes Functionalized with Borane (BH3)

In this work, desorption of hydrogen from hydrogenated single walled carbon nanotubes (SWCNTs) functionalized with borane is discussed. A hydrogen storage medium based on SWCNTs functionalized with borane is designed. The SWCNTs are functionalized with borane (BH3) using LiBH4 as the precursor by solution cast method. The functionalized samples are hydrogenated. A storage capacity of 1.5 wt.% is obtained just above room temperature (50°C). The hydrogenated and dehydrogenated samples are characterized using FTIR and Raman studies. The thermogravimetry/differential thermal analysis (TG/DTA) results reveal that the entire amount of (1.5 wt.%) stored hydrogen is released in the temperature range 100 - 150°C. This temperature range is suitable for hydrogen fuel cells used for vehicular applications.