Dw. Kim et al., IONIC-CONDUCTIVITY AND LI-7 NMR-STUDY OF SOLID POLYMER ELECTROLYTES BASED ON POLYETHERURETHANE COPOLYMER NETWORKS, Polymer Journal, 26(9), 1994, pp. 993-1001
Crosslinked polyetherurethane (PEU) copolymer networks consisting of t
he low molecular weight poly(ethylene oxide) (PEO) and poly(propylene
oxide) (PPO) segments with an aliphatic diisocyanate were synthesized
and complexed with a LiClO4 salt to form solid polymer electrolytes. T
he ionic conductivities of these samples were measured as a function o
f PEO composition at various temperatures. And a solid Li-7 NMR relaxa
tion technique was used as a means of understanding the local environm
ents and dynamics of the lithium ions in the polymer electrolytes. The
difference in spin-spin relaxation times (T2) between two spectral co
mponents enabled to their separation, and thus we could monitor the mo
bile Li+ ion concentration and its motion as a function of PEO composi
tion and temperature.