Solid-state NMR, ionic conductivity, and thermal studies of lithium-doped siloxane-poly(propylene glycol) organic-inorganic nanocomposites

Hybrid organic-inorganic ionic conductors, also called ormolytes (organical ly modified electrolytes), were obtained by dissolution of LiClO4 in siloxa ne-poly(propylene glycol) matrixes. The dynamic features of these nanocompo sites were studied and correlated to their electrical properties. Solid-sta te nuclear magnetic resonance (NMR) spectroscopy was used to probe the effe cts of the temperature and nanocomposite composition on the dynamic behavio rs of both the ionic species (Li-7) and the polymer chains (C-13). NMR, dc ionic conductivity, and DSC results demonstrate that the Li+ mobility is st rongly assisted by the segmental motion of the polymer chain above its glas s transition temperature. The ac ionic conductivity in such composites is e xplained by use of the random free energy barrier (RFEB) model, which is in agreement with their disordered and heterogeneous structures. These solid ormolytes are transparent and flexible, and they exhibit good ionic conduct ivity at room temperature (up to 10(-4) S/cm). Consequently, they are very promising candidates for use in several applications such as batteries, sen sors, and electrochromic and photoelectrochemical devices.