The Dynamics of Mobile Ions in Ionically Conducting Glasses and Other Materials

The range of applications for ionically conducting materials in technology is very broad and includes batteries; fuel cells; sensors; electrochromic displays; catalysts, oxygen, and hydrogen pumps; and bionics. In most of these applications, the mobility of the ions is a determining factor for optimum performance. Examples are liquid-electrolyte and plastic Li+ ion batteries for portable electronics, solid oxide fuel cells such as the oxygen ion-conducting stabilized zirconia electrolyte for energy conversion, and exchange of different ions in oxide glasses for the fabrication of micro-optic lenses. Therefore research on the dynamics of ionic transport that clarifies the mechanisms limiting the mobility of the ions is useful. These dynamic processes are also fascinating from a basic research point of view and qualitatively follow general patterns independent of the chemical and physical structures of the materials, suggesting that some fundamental physical mechanism is at work. On a quantitative level, the ionic-transport properties depend on the structures of the materials seemingly in well-defined patterns, which can be used to advantage in choosing materials for specific applications.