Supplementary Information
Molecular ion battery: a rechargeable system
without using any elemental ions as a charge carrier
Masaru Yao*, Hikaru Sano, Hisanori Ando, and Tetsu Kiyobayashi
Research Institute for Ubiquitous Energy Devices,
National Institute of Advanced Industrial Science and Technology (AIST)
1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan
* Corresponding author;
Tel: +81-72-751-9651; Fax: +81-72-751-9629; E-mail: m.yao@aist.go.jp
b
Voltage,
V vs. C.E.(activated carbon)
4.0
*
*
(ox.)
(ox.)
Voltage,
V vs. C.E.(activated carbon)
a
3.0
2.0
1.0
0.0
*
-1.0
(red.)
-2.0
40000
*
(red.)
60000
70000
(red.)
*
0.0
*
*
(ox.)
*
(ox.)
(ox.)
-1.0
-2.0
-3.0
*
*
(red.)
(red.)
-4.0
50000
80000
0
5000
10000
Time, s
15000
20000
25000
Time, s
Figure S1 | Typical charge/discharge curves of the cells with an activated carbon (AC) based
counter electrode for the EDX measurement. (a), The charge/discharge behavior of the PVK-AC cell. (b), The
charge/discharge behavior of the AC-PBPy cell. The measured positions were marked with asterisks (*) and the notes
of the redox state of each working electrodes.
5th discharge
*
P
6th charge
2nd charge
6th discharge
2nd discharge
7th charge
3rd charge
7th discharge
3rd discharge
1.0
1.5
**
1st discharge
2.0
Energy, keV
2.5
1.0
1.5
P
2.0
2.5
Energy, keV
Figure S2 | EDX spectral change in the electrode during cycling. (a), The change in the PVK-based
positive electrode. (b), The change in the PBPy-based negative electrode. Each of the spectra was normalized by the
intensity of the reference peaks (*: Al, **: Si).
a
c
-1
Energy Level, eV
-2
b
-3
-4
-5
-6
-7
-8
Figure S3 | Quantum chemical calculation. (a), The structure of N-methylcarbazole as a model compound for
the PVK positive electrode. (b), The structure of the fully reduced 1,1’-dimethyl-4,4’-dipyridinium skeleton as a
model compound for the PBPy negative electrode. (c), Their molecular orbitals and the calculated energy diagram.
Calculated at the UB3LYP/6-31G(d) level. The self-consistent isodensity polarizable continuum model under a high
dielectric constant environment (ε=47) was used.
a
b
c
3
2
1
0
80
60
40
20
40
60
80
100
Discharge capacity, %
120
3
2
2
1
1
20
0
0
0
4
100
Cell voltage, V
Discharge capacity, %
120
0
1
2
Current density, A g−1
3
(PVK)
4
Power, W g−1(PVK)
Cell voltage, V
3
0
0
1
2
3
4
5
Current density, A g−1(PVK)
Figure S4 | Rate capability of the prepared molecular ion battery. (a) Discharge curves at various current
densities. Inset numbers indicate the current density (A g–1). (b), Relationship between the discharge capacity and the
current density. (c), Current-voltage (I-V) and current-power (I-P) plots.
*
a
**
12
10
8
6
4
2
0
-2
δ, ppm
*
b
160
140
120
100
80
60
40
20
0
-20
δ, ppm
Figure S5. | NMR spectra of PBPy. (a) 1H-NMR spectrum. (b), 13C-NMR spectrum. Marked peaks are ascribed
to the residual hydrogen of the deuterated solvent (*) and contaminant water (**).