Dynamics of lithium ions in monoconducting polymer electrolytes: A Li-7 spin-lattice-relaxation study

In monoconducting gel electrolytes prepared from polymeric lithium salt, poly(ethylene glycol), dimethylsulfoxide or propylene carbonate Li-7(I = 3/2) NMR spin-lattice relaxation times (T-1) at two resonance frequencies (24.5 and 77.5 MHz) have been measured for various compositions of the above system over the temperature region 0.75 to 2 T-g, With the glass transition temperature T-g approximate to 200 K. The T-1 data as a function of inverse temperature exhibit a cationic diffusion-induced minimum. Both the temperature and the frequency of T-1 indicate a change in the dynamical process at about 1.3 T-g.