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Subject: search.filters.subject.Polymer electrolytes

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    A new Sodium based electrolyte – PEO10NaBrO3
    (4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Sankalpa, H. A. C.; Sumathipala, H. H.; Wijesundera, R. P.
    The necessity of new and environmental friendly rechargeable batteries is increasing day by day due to the current technology development and power demand. Hence, efficient and low-cost new electrolyte materials have to be discovered and more attention has to be placed on searching environmental friendly, non-toxic materials. Sodium salts are the most potential materials due to their abundance and low-cost. This study focuses to investigate the electrical conductivity of a sodium-based electrolyte which can be used in solid state batteries. Composite of Poly Ethylene Oxide (PEO) and Sodium Bromate (NaBrO3) are used as the electrolyte and samples were prepared by the hot-pressed method. Electrical conductivity measurements were carried out for samples prepared by varying the molar ratio of PEO and NaBrO3. According to the results, PEO-NaBrO3 has the potential to be developed as a sodium-based electrolyte. Experimental results revealed that the highest electrical conductivity is being produced for PEO10NaBrO3 samples. Best sample exhibited 3.44×10-5 S cm-1 conductivity in room temperature (30 °C) and 2.14×10-2 S cm-1 conductivity at 100 °C. These results show the evidence of potential usage of PEO10NaBrO3 as an electrolyte in solid state Batteries. However, further investigations should be carried out to investigate the contribution of the Sodium ions for the observed conductivity
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    Two new siloxanic proton conducting membranes: Part II. Proton conductivity mechanism and NMR study
    (Electrochimica Acta, 2005) di Noto, V.; Vittadello, M.; Kalfan, A.N.; Greenbaum, S.G.
    The synthesis and structural characterization of two types of membranes with formulas {Si(CH3)3O[Si(CH3)HO]21.26-[Si(CH3)((CH2)3SO3H)O]1.8-[Si(CH3)((CH2)3Si(CH3)2O-)-O]14-Si(CH3)3}n (A) and {Si(CH3)3O[Si(CH3)HO]21.26-[Si(CH3)((CH2)3SO3H)O]1.8-[Si(CH3)((CH2)3(Si(CH3)2O-w))-Ov][Si(CH3)((CH2)3Si(CH3)2O-)-O]14?vSi(CH3)3}n (B), (w=20.31), were previously proposed. The ac electrical response of A and B was fully characterized in the 40 Hz?2 MHz frequency region by studying the impedance spectra in the medium and low frequency regions by equivalent circuits and complex dielectric spectra at high frequency in terms of dielectric relaxation modes. Results demonstrated that A and B conduct ionically by means of a proton exchange event which occurs via a vehicular mechanism between neighboring water clusters formed by water molecules aggregated around each sulfonic acid group of the siloxane side chains. The proton conductivities at 115�C of ca. 1.9 ? 10?3 and 1.8 ? 10?4 S cm?1 of fully hydrated membranes A and B, respectively, classify these silicone networks as good proton conductors. Membrane B was chosen for a closer investigation using NMR spectroscopy. Solid state 29Si MAS NMR experiments gave further insight about the three-dimensional structure. Proton diffusion measurements provided some encouraging results about proton dynamics of this membrane signaling the great potential of siloxanic based proton conductors.
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    A multinuclear NMR study of ion transport in P(EO)nLiBETI complexes
    (Solid State Ionics, 2005) Suarez, S.N.; Abbrent, S.; Jayakody, J.R.P.; Greenbaum, S.G.; Shin, J.H.; Passerini, S.
    A study of ion transport in P(EO)nLiBETI complexes was undertaken, using both AC impedance and nuclear magnetic resonance (NMR) spectroscopy. 1H, 7Li and 19F NMR techniques were used to investigate structure and dynamics as a function of temperature for n=3, 6, 8, 12 and 20. Spin?lattice relaxation times (T1) and spectral information were obtained from ?50 to 100 �C. Variable temperature self-diffusion coefficients (D) and ionic conductivity (?) measurements were also performed. Anion diffusion (DF) results displayed a dependence on available free volume, increasing with decreasing salt concentration. On the other hand, cation diffusion (DLi) results did not follow this trend. DLi for n=3 and 6 suggest the presence of ionic mobility in the crystalline phase, with a significant rise above the melting point. A transition from a crystalline to amorphous phase dominated ion transport occurs at n=8. This is supported by ? results, which exhibited a VTF type of behavior for n?8 that is associated with ion transport in the amorphous phase.