Rare earth ion conduction in tungstate and phosphate solids

The quasi two-dimensional Sc-2(WO4)(3) type structure and the three-dimensional NASICON type R1/3Zr2(PO4)(3) (R=Al3+, rare earths) series were prepared and their trivalent ion conducting characteristics were compared. Among the Sc-2(WO4)(3) type and the NASICON type series, the solid electrolytes with Sc3+ as a migrating species show the highest ion conductivity. Especially, the NASICON type phosphate series holds such advantages of having a considerable high relative density and also more than seven times as high hardness compared with the Sc-2(WO4)(3) type series, promising applications for various types of devices are greatly expected. (C) 2002 Elsevier Science B.V. All rights reserved.