THE PREPARATION AND IONIC-CONDUCTIVITY OF SOL-GELS IN THE LI2O-P2O5-SIO2 SYSTEM

Glasses in the Li//2O-P//2O//5-SiO//2 system were prepared by the sol-gel technique. Ionic conductivity, thermal analysis, FTIR data and a phase diagram are reported. Monolithic xerogel specimens form only with high-silica content. X-ray powder diffraction results show the formation of crystalline lithium phosphate polymers in some samples which further polymerize and become part of the amorphous network. This is supported by IR data. The gels are shown to be phase-separated into silica-rich and phosphate-rich regions with the lithium located predominantly in the phosphate-rich regions. Ionic conductivity was found to increase strongly with increasing concentrations of both lithium and phosphate.