Electronic Supplementary Material (ESI) for RSC Advances. This journal is © The Royal Society of Chemistry 2015
Supporting Information Facile synthesis of Cu2O microstructures and their morphology dependent electrochemical supercapacitor properties Rudra Kumar, Prabhakar Rai,* Ashutosh Sharma* Department of Chemical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016, India *Corresponding authors; Email:
[email protected],
[email protected]
Calculation of the Specific Capacitance; (a) By using galvanostatic charge discharge method C= (I×∆t)/ (m×∆v) = (1×10-3 ×264)/ (1×10-3× 0.4) =660 F/g (b) By cyclic voltammetry Cm=(1/m×R×∆V)× ∫I(v)dV = (1/1×10-3×2×10-3×0.7)× 0.000903 = 645 F/g
1
Figure S1 EDS spectra of the Cu2O (a) microcubes and (b) microspheres.
(a)
Cu
cps
Cu O Al
Cu
Energy (keV)
cps
O
Cu
(b) Cu
Al
Cu
Energy (keV)
2
Figure S2 Nitrogen adsorption and desorption isotherms and corresponding pore size distribution curves (insets) of Cu2O (a) microcubes and (b) microspheres.
Volume@STP (cc/g)
(a)
Relative Pressure (P/Po) Volume@STP (cc/g)
(b)
Relative Pressure (P/Po)
Figure S3 Specific capacitance of Cu2O microcubes and microspheres at different scan rate.
Specific Capacitance (F/g)
700
Microcubes Microspheres
600 500 400 300 200 100 0
0
20
40
60
80
Scan rate (mV/s)
3
100
Figure S4 Cycling behaviour of Cu2O microcubes at 5 and 10 A/g current density.
Specific Capacitance (F/g)
600 5A/g
400 10A/g
200
0
0
200
400
600
800
No of Cycle
1000
Figure S5 (a) CV curve at different electrolyte concentration at 50 mV/s scan rate, (b) cycling stability up to 500 cycle at 50 mV/s scan rate in 6M KOH, (c) Charge-discharge behaviour at different electrolyte concentration at 1A/g current density and (d) specific capacitance at different KOH concentration at 1A/g current density for Cu2O microcubes. (a)
1M KOH 3M KOH 6M KOH 0.04 Scan Rate- 50mV/s 0.08
0.08 0.06
Current (A)
Current (A)
0.06 0.02 0.00 -0.02 -0.04 -0.06
-0.08 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
0.04 0.02 0.00 -0.02 -0.04 -0.06
1M KOH 3M KOH 6M KOH
Potential (V)
(c)
0.3 0.2 0.1 0.0
0
100
200
300
400
Time (sec.)
500
Specific Capacitance (F/g)
Potential (V)
0.4
-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
Potential (V)
700 600
4
(d)
500 400 300 200 100 0
600
(b)
Cycle Number 1 100 Scan Rate-50mV/s 300 400 500
1
2
3
4
5
KOH Concentration
6
Coulombic Efficiency (%)
Figure S6 Coulombic efficiency of Cu2O microcubes.
100 80 60 40 20 0
0
200
400
600
No of cycle
5
800
1000
Figure S7 Nyquist plots of Cu2O microcubes and microspheres. 80
(a)
70
Microcubes Microspheres
Z"(ohm)
60 50 40 30 20 10 0
1.2
0
5
10 15 20 25 30 35 40 45 50
Z' (ohm)
(b)
Microcube
Z"(ohm)
1.0 0.8 0.6 0.4 0.2 1.2
3.5
1.4
1.6
1.8
Z' (ohm)
(c)
2.0
2.2
Microsphere
Z"(ohm)
3.0 2.5 2.0 1.5 1.0 0.5 1.5
2.0
2.5
3.0
Z' (ohm)
6
3.5
4.0
Figure S8 I-V curve measurement of Cu2O microcubes and microspheres.
Current (mA)
25
Microspheres Microcubes
20 15 10 5 0
0
2
4
6
8
Voltage (mV)
7
10
Table 1 Comparison of supercapacitor properties of Cu2O microcubes with similar system reported in literature. S. N.
Materials
1.
Synthesis route
Specific Capacitance (F/g)
Capacitance Retention
RGO–Cu2O–TiO2 Hydrothermal ternary Nanocomposite,
80 F/g@ 0.2 A/g
increases from 80
2.
RGO/Cu2O Hydrothermal composite films on Cu foil
98.5 F/g @1 A/g
3
Cu@Cu2O/graphe Solvothermal ne nanocomposites
100.9 F/g at 0.1 Capacitance 3 A/g, 33.4 F/g increases from 100 F/g to 257 F/g after 1000 cycle
4
Cu2O/RGO/Ni(O H)2Nanocomposit e
923.1 A/g
5
Cu2O@Reduced Hydrothermal graphene oxide composite
Hydrothermal
Refe renc e 1
in 6 M KOH to 91.5 F/g electrolyte, 41.4 after 1000 cycles F/g, 32.7 F/g 50% after 1000 2 cycles
F/g @7.0 92.4% retention 4 even after 4,000 cycles
31.0, 26.0, and 24.0 100 % retention 5 F/g @ 100, 200, even after 5,000 and cycles 400 mA/g
6
Threedimensionally ordered macroporous Cu2O/Ni inverse opal electrodes
Electrodepositi on and Template method combined
502 F/g for 3DOM Cu2O/Ni and 191 F/g Cu2O/ flat Ni electrode
7
Cu2O/CuO/RGO nanocomposite
Hydrothermal
173.4 F/g @ 1 A/g 98.2% retention 7 to 136.3 F/g @ 10 after 100,000 A/g cycles at 10 A/g
8
3D binder-free Anodization of 862.4 F/g @ 1 A/g Cu2O@Cu Cu foam and nanoneedle arrays subsequent electrooxidation
8
85% capacitance 6 retention after 500 cycle at 10 mV/s
92% after 8 retention after 10 000 cycles
9
mesoporous Silica template 380 F/g @ 96% retention 9 2 carbon electrodes based 1mA/cm with 20 after 5000 cycles with copper oxide wt % copper @ 3mA/cm2 nanoparticles loading
10
CuO nanowires
Electrospinnin g
620 F/g @ 2 100 % retention 10 A/g,710 F/g @ after 2000 cycles 2mV/s
11
CuO nanosheet Template-free arrays grown on growth method nickel foam
569 F/g @ a 82.5% retention 11 current density of after 500 cycles 5mA/cm2
12
Graphene-Like Anodisation Copper Oxide process Nanofilms
919 F/g @ 1 A/g 93% retention 12 and 748 F/g @ 30 after 5000 cycles A/g
13
CuO nanosheet Hydrothermal clusters
535 F/g @5 mV/s
90% retention 13 after 1000 cycles
14
Cu2O Microcubes
660 F/g @ 1 A/g
80% retention This after 1000 cycle wor @ 5 A/g k
Hydrothermal
References; 1.
D. Luo, Y. Li, J. Liu, H. Feng, D. Qian, S. Peng, J. Jiang and Y. Liu, J. Alloys Comp.,
2013, 581, 303–307. 2.
X. Dong, K. Wang, C. Zhao, X. Qian, S. Chen, Z. Li, H. Liu and S. Dou, J. Alloys
Comp., 2014, 586, 745–753. 3.
Y. Li, Q. Wang, P. Liu, X. Yang, G. Dun and Y. Liu, Ceramics International, 2015,
41, 4248–4253. 4.
K. Wang, C. Zhao, S. Min and X. Qian, Electrochimica Acta, 2015, 165, 314–322.
5.
B. Li, H. Cao, G. Yin, Y. Lu and J. Yin, J. Mater. Chem., 2011, 21, 10645–10648.
9
6.
M.-J. Deng, C.-Z. Song, P.-J. Ho, C.-C. Wang, J.-M. Chen and K.-T. Lu, Phys. Chem.
Chem. Phys., 2013, 15, 7479—7483. 7.
K. Wang, X. Dong, C. Zhao, X. Qian and Y. Xu, Electrochimica Acta, 2015, 152,
433–442. 8.
C. Dong, Y. Wang, J. Xu, G. Cheng, W. Yang, T. Kou, Z. Zhang and Y. Ding, J.
Mater. Chem. A, 2014, 2, 18229–18235. 9.
K. P. S. Prasad, D. S. Dhawale, S. Joseph, C. Anand, M. A. Wahab, A. Mano, C.I.
Sathish, V. V. Balasubramanian, T. Sivakumar and A. Vinu, Microporous Mesoporous Materials, 2013, 172, 77–86. 10.
B. Vidyadharan, I. I. Misnon, J. Ismail, M. M. Yusoff and R. Jose, J. Alloys Comp.,
2015, 633, 22–30. 11.
G. Wang, J. Huang, S. Chen, Y. Gao and D. Cao, J. Power Sources, 2011, 196, 5756–
5760. 12.
Y. Lu, X. Liu,K. Qiu, J. Cheng, W. Wang, H. Yan, C. Tang, J.-K. Kim and Y. Luo,
ACS Appl. Mater. Interfaces, 2015, 7, 9682−9690. 13.
G. S. Gund, D. P. Dubal, D. S. Dhawale, S. S. Shindea and C. D. Lokhande, RSC
Adv., 2013, 3, 24099–24107.
10
