Glass-ceramics of the vanadium- or molybdenum-containing Na5RSi4O12-type (R =

rare earth; Y) Na+-superionic conductors were prepared by crystallization of

glasses with the compositions Na3+3x−yY1−xVySi3−yO9 or Na3+3x−2yY1−xMoySi3−yO9,

and the effects of V or Mo elements on the separation of the phase and the

microstructural effects on the conduction properties of glass-ceramics were

discussed. The conductivities of the glass-ceramic Na3+3x−yY1−xVySi3−yO9 and

Na3+3x−2yY1−xMoySi3−yO9 with the Na3.9Y0.6V0.3Si2.7O9 and Na3.7Y0.7Mo0.1Si2.9O9

compositions were 0.87 x 10−2 and 3.58 x 10−2S/cm at 300C, respectively, and the

Na+ ionic transport numbers of these glass-ceramics determined by Wagner

polarization method were nearly 0.9 and 1 at 300C, respectively.

Effect of Substitution of Si with V and Mo on Ionic Conductivity of Na5YSi4O12-

Type Glass-Ceramics. T.Okura, T.Takahashi, H.Monma, K.Yamashita: Solid State

Ionics, 2008, 179[27-32], 1291-5