IONIC-CONDUCTION IN THE B2S3-LI2S GLASS SYSTEM

(1-x)B2S(3-x)Li2S(0.5 < x less-than-or-equal-to 0.75) glasses have been characterized (ionic conductivity, glass transition temperature and density). The effect of quenching speed has been studied for some compositions, showing an increase in T(g) as well as a decrease in conduction activation energy and a slight decrease in density due to the extent of disorder. When the Li2S modifier content is increased, the activation energy of conductivity increases but, thanks to a strong increase in the preexponential factor, the room temperature conductivity increases. Parallelly, both T(g) and the density decrease. This is discussed as resulting from the segmentation of the structural entities due to the replacement of 4-coordinated boron-based entities by 3-coordinated boron based ones. The latter carry non bridging sulfur atoms which trap the Li+ ions.