Fast ion conduction in lithia-containing glasses after ion exchange

High electrical conductivity has been induced in silicate glasses containing Li₂O after subjecting them to a lithium/silver ion exchange treatment followed by a suitable combination of temperature and electric field. The room-temperature resistivities of these switched samples range from 50 Omega cm to 1000 Omega cm. The activation energy for conduction has values in the range 0.01 to 0.16 eV. The critical electric field for switching is found to be of the order of a few volts per centimetre. The field-induced switching is explained on the basis of growth of a silver-rich phase to the percolation configuration. Wagner's asymmetric polarisation cell measurements show that the charge carriers are ionic in the glasses in their highly conducting states.