Geoscience Reference
In-Depth Information
Figure 7.53 Luminescence spectra of
NaEuGeO
4
and NaTbGeO
4
[220]
.
7
F
2
7
F
1
7
F
3
7
F
0
660
640
620
600
580
Figure 7.54 Excitation spectrum of
NaGd
3
[GeO
4
]
2
(OH)
2
:Tb
3
1
(2.5%)
[220]
.
600
550
500
λ
(nm)
Several lithium germanates have been reported to show high ionic conductivity.
Among them, Li
14
Zn(GeO
4
)
4
is a very well-known Li
1
ion conductor. This one
phase of the solid solution phase between Li
4
GeO
4
a
Zn
2
GeO
4
is popularly known
as LISICON. The electrical conductivity of LISICON is 4
10
2
3
Ω
2
1
cm
2
1
3
at
500 K, but it decreases to less than 10
2
6
Ω
2
1
cm
2
1
at room temperature
[205,206]
.
Similarly, the alkali rare earth germanates exhibit very good ionic conductivity on
par with their rare earth silicates counterparts
[80,81]
.
