Ionic conductivity in liquid polymeric electrolytes

Effects of hydrodynamic interaction on the equivalent conductivity minimum of electrolyte solutions in solvents of low dielectric constant

Brownian dynamics simulation on model electrolyte solutions in our previous work [T. Yamaguchi et al., J. Chem. Phys. 134, 244506 (2011)] is extended to include the hydrodynamic interaction between ions, in order to examine its effects on ionic mobility in solvents of low dielectric constant. The effects of the hydrodynamic interaction are rather small as a whole, and the equivalent conductivity minimum is observed in systems with the hydrodynamic interaction. The hydrodynamic interaction increases the self-diffusion coefficient while decreases the equivalent conductivity, thereby increases the deviation from the Nernst-Einstein relationship. Based on the analysis of the time-dependent ionic mobilities, these changes are elucidated in terms of the electrophoretic and relaxation effects. It is also demonstrated that the concentration dependence of the ionic mobilities with the hydrodynamic interaction is reproduced fairly well by a theoretical calculation.

Laser Raman and ac impedance spectroscopic studies of PVA: NH4NO3 polymer electrolyte

Ion conducting polymer electrolyte PVA:NH(4)NO(3) has been prepared by solution casting technique and characterized using XRD, Raman and ac impedance spectroscopic analyses. The amorphous nature of the polymer films has been confirmed by XRD and Raman spectroscopy. An insight into the deconvoluted Raman peaks of upsilon(1) vibration of NO(3)(-) anion for the polymer electrolyte reveals the dominancy of ion aggregates at higher NH(4)NO(3) concentration. From the ac impedance studies, the highest ion conductivity at 303 K has been found to be 7.5x10(-3)Scm(-1) for 80PVA:20NH(4)NO(3). The conductivity of the polymer electrolytes has been found to depend on the degree of dissociation of the salt in the host polymer matrix. The combination of the above-mentioned analyses has proven worth while and in fact necessary in order to achieve better understanding of these complex systems.