A C-13 AND LI-6 NUCLEAR-MAGNETIC-RESONANCE STUDY OF LITHIUM PERCHLORATE POLY (ETHYLENE-OXIDE) ELECTROLYTES

C-13 and Li-6 high-resolution solid-state NMR techniques are used to morphology and dynamics of LiClO4/poly(ethylene oxide) (PEO) electrolytes. C-13 spectra and relaxation behavior are sensitive to the polymer morphology and the local chain motions. The Li-6 magic-angle spinning (MAS) NMR technique offers a detailed quantitative structural picture of the lithium atoms. At low concentrations of LiClO4 in PEO, where the conductivity rises with increasing concentration, the number of dissociated lithium ions is apparently the determining factor. At higher concentrations the observed drop in conductivity is associated with an increase in ion-ion interactions as well as decreased ion mobilities due to a lack of available sites on the polymer and due to decreasing polymer chain mobility. The number of dissociated lithium ions therefore is less important at these concentrations.