Superionic Conducting Glasses: Glass Formation and Conductivity in the AgI-Ag(2) O-P(2) O(5) System

A glass-forming region was found in the AgI-Ag(2)O-P(2)O(5) system at a Ag(2)O/P(2)O(5), mole ratio <= 3. Glass transition temperatures and conductivities at 25 degrees C for the glasses are, respectively, expressed by T(g)(degrees C) = 6.900[AgI] + 143.4[Ag(2)O] + 98.24[P(2)O(5)] -log sigma(25) (Omega(-1) cm(-1)) = 0.1952[AgI] + 5.067[ Ag(2)O] + 3.970[P(2)O(5)] where [AgI], [Ag(2)O], and [P(2)O(5)] are mole fractions of each component in the glass. These equations show that T(g) and sigma(25) are primarily governed by the AgI content. From the results, it is speculated that a portion of the silver ions forms partially covalent bonds Ag-O-P. Conductivities at room ternperature range from 10(-3) to 10(-2) to Omega(-1) cm(-1). The advantages of glass formation for obtaining solid electrolytes with higher ionic conductivity are shown. Transport numbers of silver ions are approximately unity in the glasses.