Superionic silver

Voltaic cells have been used by Malov et al. to investigate several silver salts, including superionic electrolytes synthesized on the basis of Agl, such as AgRbb, AgSI, and Agf,W04l4. 

Because of the high values of conductivity which in individual cases are found at room temperature, such compounds are often called superionic conductors or ionic superconductors but these designations are unfounded, and a more correct designation is solid ionic conductors. Strictly unipolar conduction is typical for all solid ionic conductors in the silver double salts, conduction is due to silver ion migration, whereas in the sodium polyaluminates, conduction is due to sodium ion migration. 

Structural transformation in the superionic conductor silver iodide has been investigated by employing the modified... 

The ionic charge carriers in ionic crystals are the point defects.1 2 23,24 They represent the ionic excitations in the same way as H30+ and OH-ions are the ionic excitations in water (see Fig. 1). They represent the chemical excitation upon the perfect crystallographic structure in the same way as conduction electrons and holes represent electronic excitations upon the perfect valence situation. The fact that the perfect structure, i.e., ground structure, of ionic solids is composed of charged ions, does not mean that it is ionically conductive. In AgCl regular silver and chloride ions sit in deep Coulomb wells and are hence immobile. The occurrence of ionic conductivity requires ions in interstitial sites, which are mobile, or vacant sites in which neighbors can hop. Hence a superionic dissociation is necessary, as, e.g. established by the Frenkel reaction ... 

Figure 44. The temperature dependence ofthe specific conductivity for a series of selected silver ion conductors. (AgAlnOir reads more correctly Agi+xAliiOntxn). The superionic conductors are characterized by flat slopes and high absolute values.23...

The family of Ag + and Cu + superionic conductors have been extensively studied for many decades, using a wide range of experimental and computational techniques see also Chapter 7. They are principally of interest for fundamental reasons, as model systems in which to characterize the nature ofthe dynamic disorder and to probe the factors which promote high values of ionic conductivity within the solid state. Their commercial applications are generally limited by factors such as chemical stability, the high cost of silver, and their relatively high mass when compared, for example, to lithium-based compounds. 

N. Satyanarayana, G. Govindaraj, A. Karthikeyan, Effects of differing ratios of network modifier (Ag20) to network formers (M0O3 + V2O5) and dopant salt (Agl) concentrations in silver-based superionic glassy compounds. J. Non-Cryst. Solids 136(3), 219-226 (1991)... 

Superionic Phase Transition Optimizing Thermoelectric Performance in Silver Chalcogenide Nanocrystals... 

Xiao, C., Xu, J., Li, K., Feng, J., Yang, J. L., Xie, Y. (2012). Superionic phase transition in silver chalcogenide nanocrystals realizing optimized thermoelectric performance. Journal of the American Chemical Society, 134, 4287-4293. 

Chong Xiao, Jie Xu, Kun Li, Jun Feng, Jinlong Yang, and Yi Xie (2012) Superionic Phase Transition in Silver Chalcogenide Nanocrystals Realizing Optimized Thermoelectric Performance. J. Am. Chem. Soc. 134 4287 293... 

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