WHAT DO NMR LINEWIDTHS TELL US - DYNAMICS OF ALKALI CATIONS IN A PEO-BASED NANOCOMPOSITE POLYMER ELECTROLYTE

lntercalation of poly(ethylene oxide) (PEG) into montmorillonite resul ts in a nanocomposite polymer electrolyte potentially useful for solid state secondary batteries. We have used solid state NMR to probe cati on dynamics on the timescales relevant to spatial diffusional motion o f Li+, Na+, Rb+ and Cs+ in these nanocomposites. Cation dynamics is co rrelated to the charge-carrying capacity of the material as an electro lyte. Unlike linewidth-narrowing studies on more traditional solid pol ymer electrolytes, in our systems the largest source of dipolar fields arise primarily from paramagnetic impurities fixed in the silicate la ttice. (C) 1997 Elsevier Science Ltd.