LI-7 NMR AND IONIC-CONDUCTIVITY STUDIES OF GEL ELECTROLYTES BASED ON POLY(METHYLMETHACRYLATE)

Gel electrolytes synthesized from poly(methylmethacrylate), ethylene carbonate, propylene carbonate and various lithium salts [LiClO4, LiAsF6, or LiN(CF3SO2)(2)] have been investigated by differential scanning calorimetry, electrical conductivity, and Li-7, F-19 and As-75 NMR spectroscopy. Although the ionic conductivities of the gels approach those of liquid electrolytes above room temperature, the NMR results indicate that the immediate environments of both the cations and anions differ significantly in the gel and in the liquid. Thus the presence of microscopic regions of pure liquid electrolyte in the gel can be ruled out.