Investigations were made of a series of Na, Li-X zeolites with lithium contents between 0 and 96 mole%. They were prepared by exchange of Na-X in lithium chloride solutions at 100C. The samples were carefully washed. After vacuum drying at 250C, pellets were pressed and gold electrodes were evaporated on to them. The ac conductivity was measured in the frequency range from 65kHz to 4Hz. The conductivities were measured in the temperature range from room temperature to ≈300C. Substitution of even a small amount of sodium with lithium decreases the conductivity significantly and increases the activation energy. de conductivity measurements with lithium electrodes of the most lithium rich samples have shown that they were lithium ion conductors. The logarithm of the pre-exponential factor plotted against the activation energy was linear. The slope of this line indicates that all the Arrhenius plots intersect at ≈360C. Above this temperature the lithium-containing zeolites will have higher conductivity than the sodium form. Potassium and cesium containing zeolite X was prepared (the Cs-X sample contained 58mol%Cs) and measured in the same way as the lithium form. AT 150C the specific conductivities were in the range from 5 x 10−10 for the cesium form to 3 x 10−6S/cm for the sodium form. Na-X has the highest conductivity at temperatures below 360C.

The Ionic Conductivity of Alkalimetal-Zeolite X. E.Krogh Andersen, I.G.Krogh Andersen, J.Metcalf-Johansen, K.E.Simonsen, E.Skou: Solid State Ionics, 1988, 28-30[1], 249–53