The structure and ionic conductivity of Li0.5−yNayLa0.5 {Nb,Ta}2O6 system

We have synthesized Li
0.5−y
Na
y
La
0.5
Nb
2
O
6
and Li
0.5−y
Na
y
La
0.5
Ta
2
O
6
defect perovskite solid solutions with 0 < y ≤ 0.5. Lithium ion diffusion in the investigated system exhibits no percolation effect. In the Li
0.5−y
Na
y
La
0.5
Nb
2
O
6
system, the ionic conductivity as a function of sodium content has a maximum due to two competing factors: the increase in perovskite cell volume and the decrease in lithium ion concentration. The ionic conductivity of Li
0.5−y
Na
y
La
0.5
Ta
2
O
6
samples decreases with sodium content.