Formation of superionically conducting amorphous phase in mechanically-milled AgI–Ag2O–V2O5 system

Abstract

Formation of highly ionically conducting and thermally stable amorphous phase during mechanical ball milling of AgI–Ag2O–V2O5 system is discussed. It is found that the system with composition xAgI(100−x)–66.66Ag2O–33.34V2O5 for x=50, 60 and 67 forms a highly conducting amorphous phase within 10–15 h of mechanical milling, confirmed by X-ray diffraction, glass (Tg) and amorphous to crystalline phase transition (Tc) temperatures. The ionic conductivity of mechanochemically synthesized samples is found to be ∼10−2 cm−1 at room temperature, which is appreciably higher than that of the melt-quenched glass. These systems are found to be stable at least up to ∼80 °C as confirmed by differential scanning calorimetry measurements. A tentative mechanism of amorphous phase formation is proposed. It is demonstrated that silver iodide that diffuses in Ag2O–MxOy matrix plays a key role in the formation of amorphous phase.