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 &middot (50 - x)Ag2O &middot xV2O5, 14 &le x &le 25 and y AgI &middot (80 - y)Ag2O &middot 20 V2O5, 30 &le y &le 50 was studied. The composites were prepared by annealing initially amorphous samples of the above compositions at temperatures slightly exceeding their crystallization temperatures Tc. The formation of crystallites was evidenced by X-ray diffraction patterns of the annealed samples. The structural changes induced by the annealing 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 (within hours) at stabilized temperatures exceeding glass transition temperature while the conductivity of the glasses was thermally stable only below Tg. The highest measured value of σ (0.1 S/cm at 150°C) is close to those found in the best superionic conductors at these temperatures.