Ion transport in hydrated sodium silicates (water glasses) of varying water content

Abstract

Ionic conductivities in hydrated sodium silicate gels (water glasses) of SiO 2/Na 2O 3.41:1 mole ratio have been obtained by impedance spectroscopy at temperatures above and below the thermally determined glass transition temperature. Conductivities at T g are in the range 10 −6 to 10 −7 S cm −1, which are similar to those found recently in several kinds of polymer electrolyte. It is suggested that the absence of a mixed alkali effect and a strong dependence on water imply that conductivities are largely protonic in nature and involve strong interactions between protons, water molecules and the silicate framework.