A new polymer electrolyte based on the biopolymer Agar-Agar doped with ammonium thiocyanate (NH 4 SCN) has been prepared and characterized by FTIR analysis, X-ray diffraction measurements, AC impedance spectroscopy, transference number measurements, and DSC analysis. The Fourier transform infrared analysis confirms the complex formation between agar and NH 4 SCN. The amorphous nature of the polymer electrolyte has been revealed from X-ray diffraction analysis. The highest ionic conductivity has been observed for the sample of composition 1:1 between Agar and NH 4 SCN. As a function of temperature, the ionic conductivity of this sample exhibits Arrhenius behavior increasing from 1.03 3 10 23 S cm 21 at ambient temperature to 3.16 3 10 23 S cm 21 at 343 K. The transference number has been estimated by the dc polarization method, and it has been proven that the conducting species are predominantly cations. Using the highest conductivity polymer electrolyte, solid state electrochemical cell has been fabricated and cell parameters are reported.

The proton-conducting polymer electrolytes based on poly (N-vinylpyrrolidone) (PVP), doped with ammonium chloride (NH 4 Cl) in different molar ratios, have been prepared by solution-casting technique using distilled water as solvent. The increase in amorphous nature of the polymer electrolytes has been confirmed by XRD analysis. The FTIR analysis confirms the complex formation of the polymer with the salt. A shift in glass transition temperature (T g ) of the PVP/NH 4 Cl electrolytes has been observed from the DSC thermograms which indicates the interaction between the polymer and the salt. From the AC impedance spectroscopic analysis, the ionic conductivity of 15 mol% NH 4 Cl-doped PVP polymer complex has been found to be maximum of the order of 2.51×10 −5 Scm −1 at room temperature. The dependence of T g and conductivity upon salt concentration has been discussed. The linear variation of the proton conductivity of the polymer electrolytes with increasing temperature suggests the Arrhenius type thermally activated process. The activation energy calculated from the Arrhenius plot for all compositions of PVP doped with NH 4 Cl has been found to vary from 0.49 to 0.92 eV. The dielectric loss curves for the sample 85 mol% PVP:15 mol% NH 4 Cl reveal the lowfrequency β relaxation peak pronounced at high temperature, and it may be caused by side group dipoles. The relaxation parameters of the electrolytes have been obtained by the study of Tanδ as a function of frequency.

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This work aims at developing and characterizing a proton conducting polymer electrolyte based on Poly(N-vinyl pyrrolidone) (PVP) doped with ammonium bromide (NH 4 Br). Proton conducting polymer electrolytes based on PVP doped NH 4 Br in different molar ratios have been prepared by solution casting technique using distilled water as solvent. The XRD pattern confirms the dissociation of salt. The FTIR analysis confirms the complex formation between the polymer and the salt. The conductivity analysis shows that the polymer electrolyte with 25 mol % NH 4 Br has the highest conductivity equal to 1.06 Â 10 À3 S cm À1 at room temperature. Also it has been observed that the activation energy evaluated from the Arrhenius plot is low (0.50 eV) for 25 mol % NH 4 Br doped polymer electrolyte. The influence of salt concentration on dc conductivity and activation energy of the polymer electrolyte has been discussed.

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