Supporting information - rsc.org fileSupporting Information ... GA Figure S3 UV-Vis absorption...

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Supporting Information

High-rate Capacitive Performance of Graphene Aerogel with a Superhigh C/O Molar

Ratio

Xiaozhong Wu, Jin Zhou, Wei Xing,* Guiqiang Wang, Hongyou Cui, Shuping Zhuo,*

Qingzhong Xue, Zifeng Yan, Shi Zhang Qiao*

Mr. X. Wu, Prof. W. Xing, Prof. Q. Xue, Prof. Z. Yan

School of Science

State Key Laboratory of Heavy Oil Processing

China University of Petroleum, 66, Changjiang West Road

Qingdao 266580 (P. R. China)

Email: [email protected]

Mr. X. Wu, Dr. J. Zhou, Prof. W. Xing, Prof. G. Wang, Prof. H. Cui, Prof. S. Zhuo.

School of Chemical Engineering, Shandong University of Technology

Zibo 255049 (P. R. China)

E-mails: [email protected]

Prof. S. Z. Qiao

School of Chemical Engineering

The University of Adelaide, SA5005 (Australia)

Email: [email protected]

Electronic Supplementary Material (ESI) for Journal of Materials ChemistryThis journal is © The Royal Society of Chemistry 2012

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Content

Figure S1 Optical images of GO suspension in deionized water (left) and graphene oxide

hydrogel after self-assembly process (right)

Figure S2 SAED patterns for (a) GOA and (b) GA

Figure S3 UV-Vis absorption spectra of GO, GOA and GA

Figure S4 Optical images of samples dispersed in deionized water and ethanol (solution

concentration: 0.1 mg mL-1)

Figure S5 TG and differential thermogravimetry (DTG) curves of GOA

Figure S6 FT-IR spectra of GO, GOH-D (vacuum dried graphene oxide hydrogel) and GOA

Figure S7 (a) Specific capacitance and capacitance retention ratio at different potential scan

rates; (b) a plot of specific capacitance vs. Frequency; (c) imaginary part of

capacitance vs. frequency for GOA and GA

Figure S8 The specific capacitance and its retention ratio vs. current densities of GA in

organic and ionic liquid electrolytes

Figure S9 Galvanostatic charge-discharge curves of GA at different current densities in

organic electrolyte


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Figure S1 Optical images of GO suspension in deionized water (left) and graphene oxide

hydrogel after self-assembly process (right)

Figure S2 SAED patterns for (a) GOA and (b) GA

(a) (b)


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200 300 400 500 600 700 800

GOA

GA

249 nm

269 nmAb

so

rba

nc

e

Wavelength / nm

230 nm

GO

Figure S3 UV-Vis absorption spectra of GO, GOA and GA

Figure S4 Optical images of samples dispersed in deionized water and ethanol (solution

concentration: 0.1 mg mL-1)


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0 200 400 600 800 10000

20

40

60

80

100

Wei

gh

t re

ma

inin

g /

%

Temperature / oC

40%

dW

/dT

-15%

-19%

Figure S5 TG and differential thermogravimetry (DTG) curves of GOA

The weight change of GOA during thermal treatment process under H2 atmosphere is

recorded by TG analysis. There are two obvious weight losses within the temperature ranges

of 20-150 oC and 150-300 oC, corresponding to the release of adsorbed water and

decomposition of oxygen-containing groups such as carboxylic and lactone groups, [1,2]

respectively. Other oxygen-containing groups (carbonyl, phenol, quinine and hydroxyl

groups) are decomposed at temperatures ranging from 400 to 1000 oC. [2] There is no obvious

weight change above 1000 oC, which indicates that most oxygen-containing groups are

eliminated completely at 1000 oC. The remaining weight is about 40 % when the temperature

reaches up to 1100 oC.


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4000 3000 2000 1000

3398.0

GOH-D

C=Ocarboxyl

C=C

alkoxyl C-O

GOA

epoxyl C-O

carboxyl O-H

carbonyl

Tra

ns

mit

tan

ce

Wave number / cm-1

hydroxyl

GO3383.8

1732.8

1716.9

Figure S6 FT-IR spectra of GO, GOH-D (vacuum dried graphene oxide hydrogel) and GOA

Graphene oxide hydrogel was further vacuum dried at 50 oC to obtain GOH-D. Compared

with GOH-D, there is an obvious decrease of hydroxyl groups in the spectrum of GOA, which

is probably due to the dynamic operation at high pressure (20 MPa) during supercritical CO2

drying.


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Figure S7 (a) Specific capacitance and capacitance retention ratio at different potential scan

rates in ; (b) a plot of specific capacitance vs. Frequency; (c) imaginary part of capacitance vs.

frequency for GOA and GA

0 20 40 60 80 1000

20406080

100 GOA

GA

Rat

io /

%

Potential scan rate / (mV s-1)

0

40

80

120 GOA GA

Cs

/ (F

g-1)

(a)

0.01 0.1 1 10 100 10000

20

40

60

80

100

0.5 Hz GOA GA

Cap

acit

ance

/ (

F g

-1)

Frequency / Hz

0.05 Hz

(b)

0.01 0.1 1 10 100 10000

5

10

15

20

25

30 GOA GA

0.3 s

C"

/ (

F g

-1)

Frequency / Hz

4.2 s

(C)


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0 400 800 1200 1600 20000

20406080

100

organic ionic liquid

Ra

tio

/ %

Current density / (mA g-1)

0306090

120150

organic ionic liquid

Cs

/ (

F g

-1)

Figure S8 The specific capacitance and its retention ratio vs. current densities of GA in both

organic and ionic liquid electrolytes

0 100 200 300 400 500 600 7000.0

-0.5

-1.0

-1.5

-2.0 0.5 A g-1

1 A g-1

2 A g-1

Po

ten

tial

/ V

Time / s

Figure S9 Galvanostatic charge-discharge curves of GA at different current densities in

organic electrolyte

References in supporting information

[1] S. Stankovich, D. A. Dikin, R. D. Piner, K. A. Kohlhaas, A. Kleinhammes, Y. Jia, Y. Wu,

S. T. Nguyen and R. S. Ruoff, Carbon, 2007, 45, 1558.

[2] X. Li, H. Wang, J. T. Robinson, H. Sanchez, G. Diankov and H. Dai, J. Am. Chem. Soc.,

2009, 131, 15939.


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