Micro Raman, FT-IR/PAS, XRD and SEM studies on glassy and partly crystalline silver phosphate ionic conductors

Glassy and glassy-crystalline silver ion conductors of the AgI-Ag2O-P2O5 system have been studied by FTIR-PAS and Micro Raman spectroscopies in conjunction with X-ray diffractometry, scanning electron microscopy and differential scanning calorimetry. It was found out that materials with lower (<= 60 mol%) AgI contents are fully amorphous, while those with higher contents of AgI (> 70 mol%) contain crystalline grains of beta/alpha-AgI embedded in the glassy matrix. Annealing of the glasses at 105 degrees C and/or 145 degrees C resulted in an increase in the formation of a yet unidentified crystalline phase dispersed in the glass. From the spectroscopic studies it was found that PO(4)3- units existed as separated species in the glass network or precipitated crystalline phases regardless the thermal treatment of the material. Vibrations of PO43- units appeared to be affected by the total concentration of AgI and microstructure. The spectroscopic methods were also used to study crystallization process in the glassy samples. (c) 2007 Elsevier B.V. All rights reserved.