Nuclear magnetic resonance studies of nanocomposite polymer electrolytes

Abstract

The origin of the ionic conductivity enhancement in polymer electrolytes that occurs on adding inorganic oxide powders was explored by 1H and 7Li nuclear magnetic resonance. Ionic and molecular self-diffusion coefficients determined by pulsed field gradient spin-echo measurements demonstrate that lithium ionic diffusivity is enhanced in the composites, but this enhancement is not attributed to polymer segmental mobility. Two different systems were investigated: a high-molecular-mass poly(ethylene oxide)-LiClO4 complex with nanoscale TiO2; and a low-molecular-mass poly(ethylene glycol)-LiClO4 solution with Al2O3. In the latter case the effect of varying the alumina surface acidity or basicity was considered.