Enhanced sodium ion conduction of highly dense bulk zeolite X prepared by hydrothermal hot-pressing.

Highly dense bulk zeolite X with translucency was successfully fabricated by hydrothermal hot-pressing of zeolite powder at 150 °C. Densification was achieved by addition of a small amount of distilled water or a 1 mol/L NaOH solution. Enhanced sodium ion conduction was observed for the densified bulk ceramic bodies. The ion conductivities obtained were beyond 0.001 S/cm, and are comparable to those of practical solid electrolytes applied in electrochemical devices such as batteries and chemical sensors. • Dense bulk of zeolite X was prepared by the hydrothermal hot-pressing (HHP). • High ionic conductivities beyond 0.001 S/cm were observed for dense HHP sample. • Sodium ion conduction was highly enhanced by densification. [ABSTRACT FROM AUTHOR]