Conductivity pathways and ionic transport in Na5YW4O16

The scheelite-like double tungstate Na5YW4O16 was selected by using Voronoi tessellation as a compound with suitable channels for ionic transport. The effect of charge carrier density on the ionic conductivity was investigated by heterovalent substitution of Ca2 + for Na+ and Y3 +. Ionic conductivities of ceramics at 300 °С are 3.4 · 10− 5 S/m for Na5YW4O16 and 8.5 · 10− 6 S/m for Na4.6Ca0.2YW4O16. It is proposed to use new term “pathway density” to explain low value of ionic conductivity for the studied compound.