Nanosized composites of synthetic zeolites and silver iodide as potentially electrochemically active materials

Abstract

Zeolitic composite materials made up of silver iodide and potassium form of synthetic zeolites ZSM5 were prepared in different conditions. The composites were characterized by X-ray powder diffraction methods and their electrochemical properties were studied by conductivity measurements. The attention was focused on the composites of synthetic zeolite of ZSM5 and AgI prepared by treating a silver form of synthetic zeolite ZSM5 (Ag-ZSM5) with potassium iodide solution. On the basis of the ac conductivity data it has been inferred that AgI forms a thin conductive crystalline shell on the surface of the K-ZSM5 particles. The sharp conductivity change between 142 and 147 °C is due to AgI undergoing a phase transition from hexagonal to cubic symmetry at 146 °C. The electrochemical properties of the composites depend on the mode of preparation and on the subsequent thermal treatments.