ENHANCEMENT OF THE PROTONIC CONDUCTIVITY OF ALPHA-ZIRCONIUM PHOSPHATEBY COMPOSITE FORMATION WITH ALUMINA OR SILICA

The protonic conductivity of zirconium phosphate, Zr(HPO4)(2) . H2O(al pha-ZrP), can be increased by dispersion with up to ca. 30 mole% inorg anic oxide. This positive composite effect is observed both when alpha -ZrP is coprecipitated from a delaminated form with colloidal silica a nd when it is intimately dispersed with alpha-Al2O3 by ball-milling. T he absolute value of the conductivity depends on the pre-treatment und ergone by ZrP but, in all cases, it is enhanced by 5-10 times after co mposite formation with a maximum observed at ca. 20 mole % inorganic o xide. These effects are explained in terms of local modification of th e hydrogen phosphate surface.