ANOMALOUS IONIC TRANSPORT IN GLASSY ELECTROLYTES

We discuss the dynamic structure model recently introduced by Bunde, M aass and Ingram to account for the anomalies of ionic transport in gla ssy ionic conductors. The model is based on the experimental evidence that ions in glass maintain their distinct local environments. Key fea tures include a site memory effect that introduces vacancies appropria te to each kind of mobile ion, and a mismatch energy that emerges when ever an ion attempts to enter a different kind of site, the combinatio n of both leads to the formation of fluctuating percolation pathways. The connectivity of these pathways determines the ion mobility in the glassy network. The exploration of this model by numerical methods lea ds i) to a power law relationship between ionic conductivity and catio n content (now confirmed in the literature) and ii) to the elucidation of many facets of the mixed alkali effect. It is suggested that the m odel could form the basis for a comprehensive theory of vitreous elect rolytes.