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S1
Supplementary Information
Asymmetric Supercapacitors Using 3D Nanoporous
Carbon and Cobalt Oxide Electrodes Synthesized
from a Single Metal-Organic Framework
Rahul R. Salunkhe,1 Jing Tang,
1,2 Yuichiro Kamachi,
1,3 Teruyuki Nakato,
3
Jung Ho Kim*,4
and Yusuke Yamauchi*,2
[1] World Premier International (WPI) Research Center for Materials
Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS),
1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
[2] Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku,
Tokyo 169-8555, Japan.
[3] Department of Applied Chemistry, Graduate School of Engineering, Kyushu
Institute of Technology, 1-1 Sensui-Cho, Tobata, Kitakyushu, Fukuoka 804-
8550, Japan.
[4] Institute for Superconducting and Electronic Materials, University of
Wollongong, North Wollongong, New South Wales 2500, Australia.
Keywords: nanoporous materials; coordination polymers; metal-organic frameworks;
cobalt oxide; carbon; supercapacitors
*Corresponding authors:
jhk@uow.edu.au (J.H. Kim); Yamauchi.yusuke@nims.go.jp (Y. Yamauchi)
S2
Table S1 Comparison of surface area of our Co3O4 polyhedra with previously reported
Co3O4 nanostructures produced by different synthetic routes.
Method Morphology Surface area (m2∙g-
1) Ref.
Hydrothermal method Ultralayered Co3O4 97 S1
Chemical precipitation Co3O4 Nanosheets 127 S2
Hydrothermal method Co3O4 nanorod/Ni
foam 14.74 S3
Controlled precipitation Co3O4 nanosheets 75.9 S4
MOF templated method Co3O4 microsheets 0.21 S5
Solution method Co3O4 nanosheets 25.12 S6
Topotactic transfer approach Co3O4 nanotubes 7.6 S7
Hydrothermal method
Co3O4 Nanosheet 17.8
S8 Co3O4 Nanobelt 20.1
Co3O4 Nanocubes 22.6
MOF templated method Co3O4 porous agglomerates
47.12 S9
MOF templated method Co3O4 polyhedrons 148 Our work
S3
Table S2 Comparison of electrochemical performance of our Co3O4 sample with
previous reports using standard three-electrode system.
Method Electrolyte Morphology Capacitance
(F∙g-1)
Scan rate
(mV∙s-1)
Current density (A∙g-1)
Ref.
Hydrothermal method
KOH (6M) Nanorod 456 - 1 S10
Hydrothermal method
KOH (1M) Ultra layer 548 8 S1
Controlled precipitation
method KOH (2M) Layered 202 1 S4
Hydrothermal method
NaOH (1M) Net-like 1090 10 - S11
Hydrothermal method
KOH (2M) Nanowire 754 - 2 S12
Hydrothermal method
KOH (6M) Flakes 263 - 1 S13
MOF templated
method KOH (6M) Sheets 208 - 1 S5
MOF templated
KOH (6M) Porous
polyhedron 504 5 -
Our work
S4
Table S3 Various performance parameters for our ASC supercapacitor.
Current density
(A∙g-1)
Discharge
time
(s)
Specific capacitance
(F∙g-1)
Specific energy
(W∙h∙kg-1)
Specific power
(W∙kg-1)
2 81 101.2 36 1600
3 40 75 27 2430
4 25 63 23 3312
5 19 60 22 4042
7 10.2 44.62 16.9 5964
10 7 44 15.4 7920
method
S5
Table S4 Comparison of our ASC performance of different metal oxides/hydroxides.
Materials Counter Electrolyte Operating voltage
(V)
Energy density
(W∙h∙kg-1)
Power density (W∙kg-1)
Ref.
Ni(OH)2@Ni foam
a-MEGO KOH (6M) 1.8 13.4 85000 S14
Co (OH)2 nanorods
GO KOH (1M) 1.2 11.94 2540 S15
MoO3 AC LiSO4 1.8 45 450 S16
MnO2 AC K2SO4 (0.5 M)
1.8 28.4 150 S17
MnO2 AC Na2SO4 (0.5 M)
1.8 10.4 14700 S18
Ni(OH)2 AC KOH (1 M) 1.3 35.7 490 S19
Co3O4 Nanoporous carbon
KOH (6 M) 1.6 36 1600 Our work
GO: graphene oxide
a-MEGO: activated microwave exfoliated graphite oxide
AC: activated carbon
(Note: The comparison has been made with bare metal oxides/hydroxides that used as positive electrode only and
ASC calculation based on weight of active electrode materials.)
6
Figure S1
Figure S1. Wide angle XRD pattern of ZIF-67 crystals.
Note for Figure S1: The topological information of the prepared crystals is revealed by the powder X-ray
diffraction (XRD) patterns. As shown in the Figure S1, the diffraction peaks of the prepared crystals are
identical to simulated crystal structure of the ZIF-67 crystals,S20
indicating the successful formation of ZIF-67
crystals.
7
Figure S2
Figure S2. EDS elemental mapping images of nanoporous carbon (top) and nanoporous Co3O4 (bottom). Both
samples contain carbon, cobalt, oxygen, and nitrogen as the main elements. (All scale bars shown are 1 μm in
length.)
8
Figure S3
Figure S3. (a, c) Nitrogen adsorption-desorption isotherms for (a) nanoporous carbon and (c) nanoporous
Co3O4. (b, d) Pore size distributions of (b) nanoporous carbon and (d) nanoporous Co3O4. Inset of b shows
magnified view of mesopores distribution.
9
Figure S4
Figure S4 (a) CV curves of Co3O4//carbon ASC. The device was cycled by varying the upper cell voltage from
1 V to 1.6 V. (b) Stability study of ASC up to 2000 repeated charge-discharge cycles. Inset of (b) shows the 10
charge-discharge cycles.
10
Figure S5
Figure S5 SSC tests based on nanoporous carbon electrodes. (a) CV curves of carbon//carbon SSC, with the
device cycled by varying the upper cell voltage from 1 V to 1.6 V; (b) galvanostatic discharge curves of the
carbon//carbon SSC cell at various current densities from 1-5 A∙g-1
; and (c) dependence of the specific
capacitance on the applied current density.
11
Figure S6
Figure S6 SSC tests based on nanoporous cobalt oxide electrodes. (a) CV curves of Co3O4//Co3O4 SSC, with
the device cycled by varying the upper cell voltage from 0.5 V to 0.9 V; (b) galvanostatic discharge curves of
Co3O4//Co3O4 SSC cell at various current densities from 1-5 A∙g-1
; and (c) dependence of the specific
capacitance on the applied current density.
12
Note for Figure S5 and Figure S6: Symmetric supercapacitor (SSC) studies were carried out for the
nanoporous carbon and the Co3O4. Each type of electrode, with size of 1 × 1 cm2, was used as both the positive
and negative working electrodes. In case of the SSCs, the total mass of both electrodes was adjusted to 2
mg∙cm-2
. Figure S5a shows the CV curves of the carbon//carbon SSC at various potential windows ranging
from 1.0 V to 1.6 V. It exhibits a rectangular shape, however, and after 1.6 V, a steep peak is observed, which
might be due to some irreversible chemical reactions, so the maximum working potential of this material is up
to 1.6 V. The capacitance of the SSC was evaluated by galvanostatic charge-discharge measurements (Figure
S5b). For this purpose, the applied current density was varied from 1 to 5 A∙g-1
. The absence of any initial
voltage loss (i.e. IR drop) indicates a fast current response with low internal resistance. The variation of specific
capacitance with applied current density is shown in Figure S5c. The maximum capacitance value obtained for
the symmetric carbon//carbon supercapacitor was 20 F∙g-1
at a current density of 1 A∙g-1
. Similar to the tests for
the carbon-based SSC, Co3O4 SSC tests were carried out (Figure S6a-c). The CV studies show that the
maximum working potential for the Co3O4-based supercapacitor is 0.9 V. The SSC cell shows a very
rectangular shape. The maximum capacitance value of the SSC was found to be 66 F∙g-1
at a current density of 1
A∙g-1
.
13
Figure S7
Figure S7 Heating of Co3O4 samples without preliminary nitrogen heat treatment at (a) 400 ºC and (b) 350 ºC,
respectively.
14
References
S1 Meher, S. K.; Rao, G. R., Ultralayered Co3O4 for high performance supercapacitor applications. J. Phys.
Chem. C 2011, 115, 15646-15654.
S2 Wang, Y.; Zhong, Z.; Chen, Y.; Ng, C. T.; Lin, J., Controllable synthesis of Co3O4 from nanosize to
microsize with large-scale exposure of active crystal planes and their excellent rate capability in
supercapacitors based on the crystal plane effect. Nano Res. 2011, 4, 695-704.
S3 Tang, C. H.; Yin, X.; Gong, H., Superior performance asymmetric supercapacitors based on a directly
grown commercial mass 3D Co3O4@Ni(OH)2 core-shell electrode. ACS Appl. Mater. Interfaces 2013, 5,
10574-10582.
S4 Wang, D.; Wang, Q.; Wang, T., Morphology controllable synthesis of cobalt oxalates and their
conversion to mesoporous Co3O4 nanostructures for application in supercapacitors. Inorg. Chem. 2011,
50, 6482-6492.
S5 Zhang, F.; Hao, L.; Zhang, L.; Zhang, X., Solid-state thermolysis preparation of Co3O4 nano/micro
superstructures from metal-organic framework for supercapacitors. Int. J. Electrochem. Sci. 2011, 6,
2943-2954.
S6 Xiong, S.; Yuan, C.; Zhang, X.; Xi, B.; Qian, Y., Controllable synthesis of mesoporous Co3O4
nanostructures with tunable morphology for application in supercapacitors. Chem. Eur. J. 2009, 15,
5320-5326.
S7 Lou, X. W.; Deng, D.; Lee, J. Y.; Feng, J.; Archer L. A., Self-supported formation of needlelike Co3O4
nanotubes and their application as lithium-ion battery electrodes. Adv. Mater. 2008, 20, 258-262.
S8 Hu, L.; Peng, Q.; Li, Y., Selective synthesis of Co3O4 nanocrystal with different shape and crystal plane
effect on catalytic property for methane combustion. J. Am. Chem. Soc. 2008, 130, 16136-16137.
S9 Meng, F.; Fang, Z.; Li, Z.; Xu, W.; Wang, M.; Liu, Y.; Zhang, J.; Wang, W.; Zhao, D.; Guo, X., Porous
Co3O4 materials prepared by solid-state thermolysis of a novel Co-MOF crystal and their superior energy
storage performances for supercapacitors, J. Mater. Chem. A 2013, 1, 7235-7241.
S10 Cui, L.; Li, J.; Zhang, X. G., Preparation and properties of Co3O4 nanorods as supercapacitor material. J.
Appl. Electrochem. 2009, 39, 1871-1876.
S11 Wang, H.; Zhang, L.; Tan, X.; Holt, C. M. B.; Zahiri, B.; Olsen, B. C.; Mitlin, D., Supercapacitive
properties of hydrothermally synthesized Co3O4 nanostructures. J. Phys. Chem. C 2011, 115 (35),
17599-17605.
S12 Xia, X. H.; Tu, J. P.; Zhang, Y. Q.; Mai, Y. J.; Wang, X. L.; Gu, C. D.; Zhao, X. B., Freestanding Co3O4
nanowire array for high performance supercapacitors. RSC Adv. 2012, 2, 1835-1841.
S13 Xie, L.; Li, K.; Sun, G.; Hu, Z.; Lv, C.; Wang, J.; Zhang, C., Preparation and electrochemical
performance of the layered cobalt oxide (Co3O4) as supercapacitor electrode material. J. Solid State
Electrochem. 2012, 17, 55-61.
S14 Ji, J.; Zhang, L. L.; Ji, H.; Li, Y.; Zhao, X.; Bai, X.; Fan, X.; Zhang F.; Ruoff, R. S., Nanoporous
Ni(OH)2 thin film on 3D ultrathin graphite foam for asymmetric supercapacitor. ACS Nano 2013, 7,
6237-6243.
S15 Salunkhe, R. R.; Bastakoti, B. P.; Hsu, C. T.; Suzuki, N.; Kim, J. H.; Dou, S. X.; Hu, C. C.; Yamauchi,
Y., Direct growth of cobalt hydroxide rods on nickel foam and its application for energy storage. Chem.
Eur. J. 2014, 20, 3084-3088.
S16 Tang, W.; Liu, L.; Tian S.; Li, L.; Yue, Y.; Wu, Y.; Zhu, K., Aqueous supercapacitor of high energy
density based on MoO3 nanoplates as anode material. Chem. Commun. 2011, 47, 10058-10060.
S17 Qu, Q.; Zhang P.; Wang, B.; Chen Y.; Tian, S.; Wu, Y.; Holze, Y., Electrochemical performance of
MnO2 nanorods in neutral aqueous electrolytes as a cathode for asymmetric supercapacitors. J. Phys.
Chem. C 2009, 113, 14020-14027.
S18 Wang, Y. T.; Lu, A. H.; Zhang, H. L.; Li, W. C., Synthesis of nanostructured mesoporous manganese
oxides with three-dimensional frameworks and their application in supercapacitors. J. Phys. Chem. C
2011, 115, 5413-5421.
15
S19 Li, H. B.; Yu, M. H.; Wang, F. X.; Liu, P.; Liang, Y.; Xiao, J.; Wang, C. X.; Tong, Y. X.; Yang, G. W.,
Amorphous nickel hydroxide nanospheres with ultrahigh capacitance and energy density as
electrochemical pseudocapacitor materials. Nat. Commun. 2013, 4, Article number: 1894.
S20 Banerjee, R.; Phan, A.; Wang, B.; Knobler, C.; Furukawa, H.; O’Keeffe, M.; Yaghi, O. M., High-
throughput synthesis of zeolitic imidazolate frameworks and application to CO2 capture. Science 2008,
139, 939-943.
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