We have studied the electronic structure of Li1+x[Mn0.5Ni0.5]1−xO2 (x = 0.00 and 0.05), one of the promising cathode materials for Li ion battery, by means of x-ray photoemission and absorption spectroscopy. The results show that the valences of Mn and Ni are basically 4+ and 2+, respectively. However, the Mn3+ component in the x = 0.00 sample gradually increases with the bulk sensitivity of the experiment, indicating that the Jahn-Teller active Mn3+ ions are introduced in the bulk due to the site exchange between Li and Ni. The Mn3+ component gets negligibly small in the x = 0.05 sample, which indicates that the excess Li suppresses the site exchange and removes the Jahn-Teller active Mn3+.

1.
K.
Mizushima
,
P. C.
Jones
,
P. J.
Wiseman
, and
J. B.
Goodenough
,
Mater. Res. Bull.
15
,
783
(
1980
).
2.
E.
Plichta
,
S.
Slane
,
M.
Uchiyama
,
M.
Salomon
,
D.
Chua
,
W. B.
Ebner
, and
H. W.
Lin
,
J. Electrochem. Soc.
136
,
1865
(
1989
).
3.
H. F.
Gibbard
,
J. Power Sources
26
,
81
(
1989
).
4.
T.
Nagura
and
K.
Tazawa
,
Prog. Batteries Sol. Cells
9
,
20
(
1990
).
5.
T.
Ohzuku
and
Y.
Makimura
,
Chem. Lett.
30
,
744
(
2001
).
6.
B. L.
Cushing
and
J. B.
Goodenough
,
Solid State Science
4
,
1487
(
2002
).
7.
Y.
Idemoto
,
T.
Hasegawa
,
N.
Kitamura
, and
Y.
Uchimoto
,
Electrochemistry
79
,
15
(
2011
).
8.
H.
Wadati
,
D. G.
Hawthorn
,
T. Z.
Regier
,
G.
Chen
,
T.
Hitosugi
,
T.
Mizokawa
,
A.
Tanaka
, and
G. A.
Sawatzky
,
Appl. Phys. Lett.
97
,
022106
(
2010
).
9.
H.
Wadati
,
A. J.
Achkar
,
D. G.
Hawthorn
,
T. Z.
Regier
,
M. P.
Singh
,
K. D.
Truong
,
P.
Fournier
,
G.
Chen
,
T.
Mizokawa
, and
G. A.
Sawatzky
,
Appl. Phys. Lett.
100
,
193906
(
2012
).
10.
F. M. F.
de Groot
,
J. C.
Fuggle
,
B. T.
Tole
, and
G. A.
Sawatzly
,
Phys. Rev. B
40
,
5715
(
1989
).
11.
M.
Medarde
,
A.
Fontaine
,
J. L.
García-Muñoz
,
J.
Rodríguez-Carvajal
,
M.
de Santis
,
M.
Sacchi
,
G.
Rossi
, and
P.
Lacorre
,
Phys. Rev. B
46
,
14975
(
1992
).
12.
A. N.
Vasiliev
,
O. S.
Volkova
,
L. S.
Lobanovskii
,
I. O.
Troyanchuk
,
Z.
Hu
,
L. H.
Tjeng
,
D. I.
Khomskii
,
H.-J.
Lin
,
C. T.
Chen
,
N.
Tristan
,
F.
Kretzschmar
,
R.
Klingeler
, and
B.
Büchner
,
Phys. Rev. B
77
,
104442
(
2008
).
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