Nano-scale structural inhomogeneities of CuI–Cu2MoO4 superionic conducting glass observed by high resolution transmission electron microscopy

Nano-meter sized structural inhomogeneities of (CuI)0.52–(Cu2MoO4)0.48 superionic conducting glass were investigated by high resolution transmission electron microscopy. The as-quenched sample of CuI–Cu2MoO4 is a homogeneous glass, in which the CuI component is finely and uniformly dispersed among the oxyanions of Cu2MoO4 glassy matrix. A two-step crystallization, starting at 440 and 495 K, was observed in the glass. After the first step crystallization, precipitating nano-crystalline cubic CuI 2–3 nm in diameter, the electrical conductivity increases by about 50%. On the other hand, the electrical conductivity decreases with the second crystallization event forming crystalline phases of CuI, Cu2O and others 20–30 nm in diameter.