Supporting Information for
Metastable and Nanosize Cation-Disordered Rocksalt-type Oxides; Revisit on
Stoichiometric LiMnO2 and NaMnO2
Takahito Sato1, Kei Sato1, Wenwen Zhao1,2, Yoshio Kajiya3 and Naoaki Yabuuchi1,2,4*
1Department of Applied Chemistry, Tokyo Denki University, 5 Asahicho Senju, Adachi, Tokyo
120-8551, Japan
2Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, f1-30 Goryo-Ohara,
Nishikyo-ku, Kyoto 615-8245, Japan
3Technology Department, Electronic Materials Group, JX Nippon Mining & Metals Corporation,
1-2, Otemachi 1-Chome, Chiyoda-ku, Tokyo 100-8164, Japan
4Department of Chemistry and Life Science, Yokohama National University, 79-5 Tokiwadai,
Hodogaya-ku, Yokohama, Kanagawa 240-8501
*Corresponding Author
E-mail: [email protected]
Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A.This journal is © The Royal Society of Chemistry 2018
20 40 60 80 100
600 rpm, 12 h
600 rpm, 24 h
221
021
200
11001
0
220
200
2deg. (Cu K)
600 rpm, 36 h111
Before mechanical millinga = 4.583 Å, b = 5.760 Å,c = 2.814 Å, V = 74.30 Å3
a = 4.166 Å,V = 72.28 Å3
Figure S1. Changes in XRD patterns from zigzag-layered LiMnO2 to rocksalt LiMnO2 during
mechanical milling.
40 60 80 100
calculated observed difference
2/ deg. (Cu K)
Formula Rocksalt-type Li1.0Mn1.0O2
Space group Fm-3m, a = 4.153(5) Å
Rwp = 8.72%, RB = 6.80%
Atom Site x y z B / Å2 g
Li 4a 0 0 0 0.4 0.42
Mn 4a 0 0 0 0.4 0.5
O 4b 0.5 0.5 0.5 1.5 1.0
Figure S2. A fitting result of rocksalt LiMnO2 by Rietveld analysis. Note that the presence of
defects at Li sites is considered for the analysis, which is further discussed in the later section.
10th
0 50 100 150 200
1
2
3
4
5
10th
Volta
ge
/ V
Capacity / mA h g-1
10th
1.5 - 4.8 V, 10 mA g-1, at R.T.
Figure S3. Charge/discharge curves of 10th cycle for zigzag layered LiMnO2.
1.0
2.0
3.0
4.0
5.0285 mA h g-1
As-prepared rocksalt LiMnO2
Theoretical capacity based on Li-contents
10th
Volta
ge /
V
1st
After Mixing with AB10th 1st
0 50 100 150 200 250 300
1.0
2.0
3.0
4.0
5.0
Volta
ge /
V
Capacity / mA h g-1
Figure S4. Charge/discharge curves of rocksalt LiMnO2 before/after mixing with AB by ball milling
at 10 mA g-1.
After Mixing with AB
2 µm
2 µm
As-prepared rocksalt LiMnO2
Mn
C
Mn/C
Figure S5. Comparison of SEM images of rocksalt LiMnO2 before/after mixing with AB by ball
milling. EDX mappings of the sample after milling with AB are also shown. Carbon is uniformly
distributed in the sample after milling.
10 20 30
22020
0
Full discharge
Full charge
2deg. ( = 0.5003 Å)
Pristine
Charge to 100 mA h g-1
a = 4.173 Å, V = 72.67 Å3
a = 4.104 Å, V = 69.12 Å3
a = 4.072 Å, V = 67.52 Å3
a = 4.172 Å, V = 72.62 Å3
111
0 50 100 150 200 2501
2
3
4
5
Volta
ge
/ V
Capacity / mA h g-1
1.5 - 4.8 V, 10 mA g-1, R.T.
Figure S6. Ex-situ synchrotron XRD patterns of rocksalt LixMnO2 for the initial charge/discharge
process.
20 40 60 80 100
Al
5th cycle
2deg. (Cu K)
Pristine
1st cycle
Al
* : Sample holder
AlAl
Figure S7. Changes in XRD patterns of rocksalt LixMnO2 upon electrochemical cycles.
40 60 80 100
220
200
* : Al foil
a = 4.085 Å, V = 68.16 Å3
a = 4.418 Å, V = 86.24 Å3
*
Full discharge
2 / deg. (Cu K)
Full charge
*
Pristine
a = 4.420 Å, V = 86.33 Å311
1
Figure S8. Changes in XRD patterns of rocksalt NaxMnO2 for the initial charge/discharge process.
6540 6560 6580
Nor
mal
ized
Inte
nsity
/ a.
u.
Energy / eV
Mn K-edge Full charge
Full discharge
Mn2O3
MnO2
6540 6542 6544 6546 6548 6550
Energy / eV
Full chargeFull discharge
Figure S9. XAS spectra of fully charged/discharged rocksalt LixMnO2 with Mn2O3 and MnO2 used
as reference materials. Pre-edge data are also highlighted in the inset.
0 50 100 150 2000.0
1.0
2.0
3.0
4.0
5.0
400 mA g-1
50 mA g-1100 mA g-1
200 mA g-1
20 mA g-1
Volta
ge /
V
Capacity / mA h g-1
Rocksalt NaMnO2
Figure S10. Rate capability of rocksalt NaxMnO2. The cell was charged at 10 mA g-1 and then
discharged at different rates. Sample loading was 1.85 mg cm-2.
