Geoscience Reference
In-Depth Information
promising candidates for cathode materials in lithium secondary batteries to replace
the expensive cobalt used in present commercial cells. A manganese oxide that
behaved like the layered LiCoO
2
would be a prime candidate for this application
because of its high free energy of reaction with Li and relatively low cost
[142]
.
The experiments involved reacting potassium permanganate with hydrochloric acid
and then hydrothermally treating the reaction mixture. The overall reaction takes
place as follows:
KMnO
4
1
ð
1
x
2y
Þ=
2H
2
O
!
K
2
MnO
2
yH
2
O
1
ð
1
x
Þ
KOH
1
ð
3
x
Þ=
4O
2
2
1
2
1
ð
:
Þ
9
13
Figure 9.32
shows the schematic diagram of layered manganates showing (a)
anhydrous material and (b) one water layer and two water layers.
Demazeau et al.
[143]
have obtained La
2
MnIrO
6
belonging to the perovskite
family using a simple approach of ferromagnetic interactions through a 180
C
super exchange. The structural and magnetic studies have confirmed the
Figure 9.32 Schematic diagram of layered
manganates showing (a) anhydrous material,
(b) one water layer, and (c) two water
layers
[142]
.
(a)
4.7-6 Å
±H
2
O
(b)
7 Å
±H
2
O
(c)
10 Å
