Ionic conductivity of glass-ceramic composites in the AgI-Ag2O-V2O5 system

Electrical ionic conductivity of two families of silver-vanadate superionic glass-ceramic composites: 50 AgI . (50 - x)Ag2O . xV(2)O(5), 14 less than or equal to x less than or equal to 25 and yAgI . (80 - y)Ag2O . 20 V2O5, 3 0 less than or equal to y less than or equal to 50 was studied. The composi tes were prepared by annealing initially amorphous samples of the above com positions at temperatures slightly exceeding their crystallization temperat ures T-c. The formation of crystallites was evidenced by X-ray diffraction patterns of the annealed samples. The structural changes induced by the ann ealing were closely correlated with the modifications of ionic conductivity . The conductivity of the obtained composites was, at elevated temperatures , higher than that of the original glasses. Moreover it did not change (wit hin hours) at stabilized temperatures exceeding glass transition temperatur e while the conductivity of the glasses was thermally stable only below T-g . The highest measured value of sigma (0.1 S/cm at 150 degreesC) is close t o those found in the best superionic conductors at these temperatures.