Supporting Information Mesoporous Hybrids of Reduced Graphene
Supporting Information
Mesoporous Hybrids of Reduced Graphene Oxide and Vanadium Pentoxide for Enhanced Performance in Lithium-ion Batteries and Electrochemical Capacitors Gaind P. Pandeya, †, Tao Liua, †, Emery Browna, Yiqun Yanga, Yonghui Lib, Xiuzhi Susan Sunb, Yueping Fanga, c, and Jun Lia,* a b
Department of Chemistry, Kansas State University, Manhattan, KS 66506, United States
Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506, United States c
†
The Institute of Biomaterial, College of Materials and Energy, South China Agricultural University, Guangzhou, Guangdong 510642, China.
These authors contributed equally to this work.
*
Corresponding author: [email protected]
S-1
Control experiments of reduced GO To confirm the reduction of GO, the starting GO was subjected to the solvothermal process at similar conditions (at 180 oC) without adding VTIP precursor. The as-prepared rGO was characterized by TGA, Raman spectroscopy and X-ray diffraction (XRD). Figure S1(a) shows the TGA curves of GO and solvothermally prepared rGO. The rGO is stable up to 350 oC which confirms that the main oxygenated functional groups are removed leading to reduced GO (i.e. rGO). Figure S1(b) shows the typical Raman spectra recorded with GO and rGO samples, showing characteristic D band at 1348 cm1
and G band 1588 cm-1, respectively. The peak intensity of D band increased upon thermal treatment,
which indicates the removal of oxygenated functional groups attached on carbon backbones. Typical XRD spectra for GO and rGO are presented in Figure S1(c). The XRD peaks from the stacked atomic planes of GO and rGO appear at the two-theta angle of ~12.5o and 24.0o, respectively. Corresponding to the interlayer spacing of 7.08 Å for GO and 3.71 Å for rGO, respectively. This evidence further confirms the reduction of GO by solvothermal method.1
S-2
D
(a)
100
(b)
G
rGO
Intensity (a. u.)
60
GO
rGO
40
GO 20 100
200
300
400
500
600
700 1000
1200
o
1400
1600
1800
2000
-1
Temperature ( C)
Raman shift (cm )
(c)
d = 3.71 Å Intensity (a.u.)
Weight (%)
80
rGO
d = 7.08 Å
GO
10
15
20
25
30
35
40
2
Figure S1: (a) TGA curves, (b) Raman spectra and (c) XRD patterns of graphene oxide (GO) and solvothermally reduced graphene oxide (rGO) (at similar conditions used to prepared rGO-V2O5 hybrid).
S-3
Deriving the weight percentage of rGO and V2O5 from TGA data: The weight percentages of rGO and V2O5 in the vacuum-annealed rGO-V2O5 hybrid can be derived from the TGA data of the control sample (Figure S1a) and the hybrid sample (Figure 3c). In both samples, the weight loss before 200 oC is attributed to evaporation of the absorbed water. The weight loss between 250 and 500 oC in the bare GO sample is ascribed to the thermal reduction of GO (by reducing the amount of oxygenated groups bound to the GO flakes) but ~ 35% of the mass remains at 700 oC, likely due to graphitized carbon. In the case of the vacuum-annealed rGO-V2O5 hybrid, the thermal reduction of rGO is pushed up to around 450 oC and a nearly constant mass of 87.6% is retained up to 700 oC. As shown in Figure S1a, the bare rGO sample (produced as a control with the similar hydrothermal process) has much higher thermal stability than GO, retaining ~ 80.0% of its mass at 700 oC. Assuming that the thermal property of rGO in rGO-V2O5 hybrid is the same as bare rGO and the mass loss in the hybrid between 200 oC (~93.5%) and 700 oC (~87.6%) is purely from further reduction of rGO while the mass of V2O5 remains constant in this temperature range (since it has already been annealed at 300 oC for 2 h in vacuum), we can have: 93.5% - 87.6% = (1 – 80.0%) x FrGO
(1)
where FrGO is the weight percentage of rGO in the starting sample (annealed rGO-V2O5 hybrid) at the room temperature. Hence we can derive FrGO = 29.5%. Thus the weight percentage of V2O5 in the hybrid is: FV2O5 = 1 - FrGO – FH2O = 1 – 29.5% - (1 – 93.5%) = 64.0%
(2)
Thus there are ~29.5% of rGO and ~64.0% of V2O5 in the hybrid at room temperature. The specific capacitance of supercapacitors and the specific Li storage capacity in LIBs in later studies are all based on the mass of V2O5 calculated with this estimated weight percentage.
S-4
(a)
(b)
(c)
500 nm
1 µm (d)
2 µm
(e)
500 nm
(f)
100 nm (g)
100 nm
20 nm (f)
100 nm
Figure S2: (a, b, c) SEM and (d, e, f) TEM images of rGO-V2O5 hybrid after annealing in vacuum at 300 oC for 2 h. (g, h) show TEM images of as-prepared rGO-V2O5 hybrid for comparison.
S-5
75
2
-1
5
Current (A gV O )
50 25 0 -25 100 mV/s 200 mV/s 300 mV/s 400 mV/s 500 mV/s
-50 -75
0.0
0.2
0.4
0.6
0.8
Voltage (V) Figure S3: CV curves of the symmetric supercapacitor cell at high scan rates from 100 to 500 mV s-1.
S-6
0.15
-1
0.1 mV s
-2
Current (mA cm )
0.10 0.05 0.00 -0.05 -0.10 -0.15 2.0
2.5
3.0
3.5
4.0
+
Potential (V vs. Li/Li )
Figure S4: CV curve of the LIB half-cell with a rGO-V2O5 cathode and a Li foil anode at 0.1 mV s-1 scan rate in the potential range 4.0 to 2.0 V versus Li/Li+.
S-7
Table S1: Comparison of the supercapacitor performance of this study with literature.
Material
Capacitance (F g-1)
V2O5/rGO
VO2/rGO VOx Nanotubes/
Synthesis Method
537 (1A g-1) 225 -1
(0.25 A g ) 210 -1
(1A g )
VO2 Nanobelt/
426
3D rGO
(1A g-1)
Graphene/
195 -1
Solvothermal
0.01 mg
Hydrothermal
3 mg
Hydrothermal
-
Hydrothermal
1 mg
Hydrothermal
-
V2O5
(1A g )
MWCNTs/
510
Hierarchical Bottom
V2O5
(1mV s-1)
-up Assembly
V2O5
80
Nanowires/rGO
(0.5 A g-1) 183 -1
(0.5 A g )
V2O5 Nanowires
440
/CNTs
(0.25 A g-1)
V2O5/Carbon
295 -1
Composite
(5 mV s )
Flexible
129.7
V2O5/rGO
(0.1 A g-1)
V2O5/rGO
Material
Electrolyte
Mass
rGO
VOx/rGO
Cell
Active
-
Hydrothermal
-
Solvothermal
5 mg
Hydrothermal
-
Spray Pyrolysis
-
Hydrothermal
20 mg
484
Capping Agent
(0.5 A g-1)
Co-Precipitation
-
configuretion (# of Electrodes)
8M LiCl 0.5M K2SO4 1M Na2SO4 0.5M K2SO4 0.5M K2SO4 0.5M K2SO4 1M LiTFSI 0.5M Na2SO4 1M Na2SO4 2M KCl 1M LiClO4 0.5 M K2SO4
3
2
2
3
3
4
2
5
3
6
3
7
2
8
3
9
3
10 11
3
12
2
13
3
14
466 rGO/V2O5
(2 mV s-1)
(Present Study)
450
Solvothermal
(0.5 A g-1)
S-8
2 mg
Ref.
1M Na2SO4
2
,
Table S2: Comparison of the lithium storage performance of this study with literature. Material
V2O5-rGO
V2O5-Graphene
Capacity (mAh g-1) 235 -1
(20 mA g ) 243 -1
(50 mA g )
Synthesis Method
Electrolyte
Hydrothermal
LiPF6
Slow Hydrolysis
1.2 M LiPF6
Sol-gel
1.2 M LiPF6
Solvothermal
1 M LiPF6
Synthetic Reaction
1 M LiPF6
Hydrothermal
1 M LiPF6
Additives
Ref.
1:1:1
15
(EC:DMC:DEC) 3:7
16
(EC:EMC)
+
V2O5-Graphene (2% Graphene)
V2O5/rGO
438 (3 Li insertion) (C/20) 211 -1
(190 mA g )
V2O5-Graphene
278
Nanoribbons
(C/10)
Graphene Oxide
240 -1
Coated V2O5
(100 mA g )
rGO-Enwrapped
287
V2O5 Nanorods V2O5 Nanocrystals on rGO Balls
Hydrothermal -1
(100 mA g ) 280 -1
(300 mA g )
V2O5 Nanowires-
225
rGO Composites
(C/5)
rGO-V2O5
295
(Present Study)
(31.3 mA g-1)
followed by Reflux
1 M LiPF6
Spray Pyrolysis
1 M LiPF6
Electrospinning
1 M LiPF6
Solvothermal
1 M LiPF6
S-9
3:7
17
(EC:EMC) 1:1
18
(EC:DMC) 1:1:1
19
(EC:DEC:DMC) 1:1:1
20
(EC:DEC:DMC) 1:1
21
(EC:DMC) 1:1
22
(EC:DMC) 1:1 (EC:DMC) 1:1:1 (EC:DMC:DEC)
23
Table S3: EIS fitting parameters of the LIB half-cell with a rGO-V2O5 cathode and a Li foil anode at different insertion (discharging) potentials. Potential (V) 3.2
Rs (ohm) 5.66
2.7
Ce
4.93E-4
Re (ohm) 22.13
2.55E-5
Rct (ohm) 36.18
0.539
5.46
5.38E-6
21.41
5.18E-5
47.32
0.478
2.4
5.48
5.37E-4
20.07
4.95E-5
45.37
0.437
2.2
5.47
3.86E-3
21.38
5.09E-6
40.67
0.372
(Ω-1sn)
Cdl
(Ω-1sn)
W
Table S4: EIS fitting parameters of the LIB half-cell with a rGO-V2O5 cathode and a Li foil anode at different extraction (charging) potentials. Potential (V) 2.4
Rs (ohm) 5.13
2.7
Ce
2.92E-6
Re (ohm) 25.53
3.74E-5
Rct (ohm) 56.65
0.325
5.45
4.22E-6
24.72
5.18E-5
43.08
0.408
3.2
5.65
5.37E-4
18.68
4.95E-5
36.51
0.487
3.5
5.63
4.23E-5
21.75
5.14E-6
32.91
0.800
(Ω-1sn)
S-10
Cdl
(Ω-1sn)
W
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2.
Li, M.; Sun, G.; Yin, P.; Ruan, C.; Ai, K., Controlling the Formation of Rodlike V2O5 Nanocrystals on Reduced Graphene Oxide for High-Performance Supercapacitors. ACS Applied Materials and Interfaces 2013, 5, 11462-11470.
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Deng, L.; Zhang, G.; Kang, L.; Lei, Z.; Liu, C.; Liu, Z.-H., Graphene/VO2 hybrid material for high performance electrochemical capacitor. Electrochemica Acta 2013, 112, 448-457.
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Xu, J.; Sun, H.; Li, Z.; Lu, S.; Zhang, X.; Jiang, S.; Zhu, Q.; Zakharova, G. S., Synthesis and electrochemical properties of graphene/V2O5 xerogels nanocomposites as supercapacitor electrodes. Solid State Ionics 2014, 262, 234-237.
7.
Shakir, I.; Choi, J. H.; Shahid, M.; Shahidd, S. A.; Rana, U. A.; Sarfraz, M.; Kang, D. J., Ultrathin and uniform coating of vanadium oxide on multiwall carbon nanotubes through solution based approach for high-performance electrochemical supercapacitors. Electrochimica Acta 2013, 111, 400-404.
8.
Perera, S. D.; Liyanage, A. D.; Nijem, N.; Ferraris, J. P.; Chabal, Y. J.; Jr., K. J. B., Vanadium oxide nanowire-Graphene binder free nanocomposite paper electrodes for supercapacitors: A facile green approach. Journal of Power Sources 2013, 230, 130-137.
9.
Li, H.; Wei, J.; Qian, Y.; Zhang, J.; Yu, J.; Wang, G.; Xu, G., Effects of the graphene content and the treatment temperature on the supercapacitive properties of VOx/graphene nanocomposites. Colloids and Surfaces A: Physicochem. Eng. Aspects 2014, 449, 148-156.
10. Chen, Z.; Qin, Y.; Weng, D.; Xiao, Q.; Yiting Peng; Wang, X.; Li, H.; Wei, F.; Lu, Y., Design and Synthesis of Hierarchical Nanowire Composites for Electrochemical Energy Storage. Advanced Functional Materials 2009, 19, 3420-3426. 11. Chen, Z.; Augustyn, V.; Wen, J.; Zhang, Y.; Shen, M.; Dunn, B.; Lu, Y., High-Performance Supercapacitors Based on Intertwined CNT/V2O5 Nanowire Nanocomposites. Advanced Materials 2011, 23, 791-795. 12. Wang, B.; Konstantinova, K.; Wexlera, D.; Liub, H.; Wang, G., Synthesis of nanosized vanadium pentoxide/carbon composites by spray pyrolysis for electrochemical capacitor application. Electrochemica Acta 2009, 54, 1420–1425. 13. Foo, C. Y.; Sumboja, A.; Tan, D. J. H.; Wang, J.; Lee, P. S., Flexible and Highly Scalable V2O5 rGO Electrodes in an Organic Electrolyte for Supercapacitor Devices. Advanced Energy Materials 2014, 4, 1400236. 14. Saravanakumar, B.; Purushothaman, K. K.; Muralidharan, G., Fabrication of two-dimensional reduced graphene oxide supported V2O5 networks and their application in supercapacitors. Materials Chemistry and Physics 2015, 1-10. S-11
15. Zhao, H.; Pan, L.; Xing, S.; Luo, J.; Xu, J., Vanadium oxidesereduced graphene oxide composite for lithium-ion batteries and supercapacitors with improved electrochemical performance. Journal of Power Sources 2013, 222, 21-31. 16. Li, Z.-F.; Zhang, H.; Liu, Q.; Liu, Y.; Stanciu, L.; Xie, J., Hierarchical Nanocomposites of Vanadium Oxide Thin Film Anchored on Graphene as High-Performance Cathodes in Li-Ion Batteries. ACS Applied Materials and Interfaces 2014, 6, 18894−18900. 17. Liu, Q.; Li, Z.-F.; Liu, Y.; Zhang, H.; Ren, Y.; Sun, C.-J.; Lu, W.; Zhou, Y.; Stanciu, L.; Stach, E. A.; Xie, J., Graphene-modified nanostructured vanadium pentoxide hybrids with extraordinary electrochemical performance for Li-ion batteries. Nature Communications 2014, 6, 1-10. 18. Rui, X.; Zhu, J.; Sim, D.; Xu, C.; Zeng, Y.; Hng, H. H.; Lim, T. M.; Yan, Q., Reduced graphene oxide supported highly porous V2O5 spheres as a high-power cathode material for lithium ion batteries. Nanoscale 2011, 3, 4752-4758. 19. Yang, Y.; Li, L.; Fei, H.; Peng, Z.; Gedeng Ruan; Tour, J. M., Graphene Nanoribbon/V2O5 Cathodes in Lithium-Ion Batteries. ACS Applied Materials and Interfaces 2014, 6, 9590−9594. 20. Channu, V. S. R.; Ravichandran, D.; Rambabu, B.; Holze, R., Carbon and functionalized graphene oxide coated vanadium oxide electrodes for lithium ion batteries. Applied Surface Science 2014, 305, 596-602. 21. Chen, D.; Quan, o.; Luo, S.; Luo, X.; Deng, F.; Jiang, H., Reduced graphene oxide enwrapped vanadium pentoxide nanorods as cathode materials for lithium-ion batteries. Physica E 2014, 56, 231-237. 22. Choi, S. H.; Kang, Y. C., Uniform Decoration of Vanadium Oxide Nanocrystals on Reduced Graphene-Oxide Balls by an Aerosol Process for Lithium-Ion Battery Cathode Material. Chem. Eur. J. 2014, 20, 6294-6299. 23. Pham-Cong, D.; Ahn, K.; Hong, S. W.; Jeong, S. Y.; Choi, J. H.; Doh, C. H.; Jin, J. S.; Jeong, E. D.; Cho, C. R., Cathodic performance of V2O5 nanowires and reduced graphene oxide composites for lithium ion batteries. Current Applied Physics 2014, 14, 215-221.
S-12
Mesoporous Hybrids of Reduced Graphene Oxide and Vanadium Pentoxide for Enhanced Performance in Lithium-ion Batteries and Electrochemical Capacitors Gaind P. Pandeya, †, Tao Liua, †, Emery Browna, Yiqun Yanga, Yonghui Lib, Xiuzhi Susan Sunb, Yueping Fanga, c, and Jun Lia,* a b
Department of Chemistry, Kansas State University, Manhattan, KS 66506, United States
Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506, United States c
†
The Institute of Biomaterial, College of Materials and Energy, South China Agricultural University, Guangzhou, Guangdong 510642, China.
These authors contributed equally to this work.
*
Corresponding author: [email protected]
S-1
Control experiments of reduced GO To confirm the reduction of GO, the starting GO was subjected to the solvothermal process at similar conditions (at 180 oC) without adding VTIP precursor. The as-prepared rGO was characterized by TGA, Raman spectroscopy and X-ray diffraction (XRD). Figure S1(a) shows the TGA curves of GO and solvothermally prepared rGO. The rGO is stable up to 350 oC which confirms that the main oxygenated functional groups are removed leading to reduced GO (i.e. rGO). Figure S1(b) shows the typical Raman spectra recorded with GO and rGO samples, showing characteristic D band at 1348 cm1
and G band 1588 cm-1, respectively. The peak intensity of D band increased upon thermal treatment,
which indicates the removal of oxygenated functional groups attached on carbon backbones. Typical XRD spectra for GO and rGO are presented in Figure S1(c). The XRD peaks from the stacked atomic planes of GO and rGO appear at the two-theta angle of ~12.5o and 24.0o, respectively. Corresponding to the interlayer spacing of 7.08 Å for GO and 3.71 Å for rGO, respectively. This evidence further confirms the reduction of GO by solvothermal method.1
S-2
D
(a)
100
(b)
G
rGO
Intensity (a. u.)
60
GO
rGO
40
GO 20 100
200
300
400
500
600
700 1000
1200
o
1400
1600
1800
2000
-1
Temperature ( C)
Raman shift (cm )
(c)
d = 3.71 Å Intensity (a.u.)
Weight (%)
80
rGO
d = 7.08 Å
GO
10
15
20
25
30
35
40
2
Figure S1: (a) TGA curves, (b) Raman spectra and (c) XRD patterns of graphene oxide (GO) and solvothermally reduced graphene oxide (rGO) (at similar conditions used to prepared rGO-V2O5 hybrid).
S-3
Deriving the weight percentage of rGO and V2O5 from TGA data: The weight percentages of rGO and V2O5 in the vacuum-annealed rGO-V2O5 hybrid can be derived from the TGA data of the control sample (Figure S1a) and the hybrid sample (Figure 3c). In both samples, the weight loss before 200 oC is attributed to evaporation of the absorbed water. The weight loss between 250 and 500 oC in the bare GO sample is ascribed to the thermal reduction of GO (by reducing the amount of oxygenated groups bound to the GO flakes) but ~ 35% of the mass remains at 700 oC, likely due to graphitized carbon. In the case of the vacuum-annealed rGO-V2O5 hybrid, the thermal reduction of rGO is pushed up to around 450 oC and a nearly constant mass of 87.6% is retained up to 700 oC. As shown in Figure S1a, the bare rGO sample (produced as a control with the similar hydrothermal process) has much higher thermal stability than GO, retaining ~ 80.0% of its mass at 700 oC. Assuming that the thermal property of rGO in rGO-V2O5 hybrid is the same as bare rGO and the mass loss in the hybrid between 200 oC (~93.5%) and 700 oC (~87.6%) is purely from further reduction of rGO while the mass of V2O5 remains constant in this temperature range (since it has already been annealed at 300 oC for 2 h in vacuum), we can have: 93.5% - 87.6% = (1 – 80.0%) x FrGO
(1)
where FrGO is the weight percentage of rGO in the starting sample (annealed rGO-V2O5 hybrid) at the room temperature. Hence we can derive FrGO = 29.5%. Thus the weight percentage of V2O5 in the hybrid is: FV2O5 = 1 - FrGO – FH2O = 1 – 29.5% - (1 – 93.5%) = 64.0%
(2)
Thus there are ~29.5% of rGO and ~64.0% of V2O5 in the hybrid at room temperature. The specific capacitance of supercapacitors and the specific Li storage capacity in LIBs in later studies are all based on the mass of V2O5 calculated with this estimated weight percentage.
S-4
(a)
(b)
(c)
500 nm
1 µm (d)
2 µm
(e)
500 nm
(f)
100 nm (g)
100 nm
20 nm (f)
100 nm
Figure S2: (a, b, c) SEM and (d, e, f) TEM images of rGO-V2O5 hybrid after annealing in vacuum at 300 oC for 2 h. (g, h) show TEM images of as-prepared rGO-V2O5 hybrid for comparison.
S-5
75
2
-1
5
Current (A gV O )
50 25 0 -25 100 mV/s 200 mV/s 300 mV/s 400 mV/s 500 mV/s
-50 -75
0.0
0.2
0.4
0.6
0.8
Voltage (V) Figure S3: CV curves of the symmetric supercapacitor cell at high scan rates from 100 to 500 mV s-1.
S-6
0.15
-1
0.1 mV s
-2
Current (mA cm )
0.10 0.05 0.00 -0.05 -0.10 -0.15 2.0
2.5
3.0
3.5
4.0
+
Potential (V vs. Li/Li )
Figure S4: CV curve of the LIB half-cell with a rGO-V2O5 cathode and a Li foil anode at 0.1 mV s-1 scan rate in the potential range 4.0 to 2.0 V versus Li/Li+.
S-7
Table S1: Comparison of the supercapacitor performance of this study with literature.
Material
Capacitance (F g-1)
V2O5/rGO
VO2/rGO VOx Nanotubes/
Synthesis Method
537 (1A g-1) 225 -1
(0.25 A g ) 210 -1
(1A g )
VO2 Nanobelt/
426
3D rGO
(1A g-1)
Graphene/
195 -1
Solvothermal
0.01 mg
Hydrothermal
3 mg
Hydrothermal
-
Hydrothermal
1 mg
Hydrothermal
-
V2O5
(1A g )
MWCNTs/
510
Hierarchical Bottom
V2O5
(1mV s-1)
-up Assembly
V2O5
80
Nanowires/rGO
(0.5 A g-1) 183 -1
(0.5 A g )
V2O5 Nanowires
440
/CNTs
(0.25 A g-1)
V2O5/Carbon
295 -1
Composite
(5 mV s )
Flexible
129.7
V2O5/rGO
(0.1 A g-1)
V2O5/rGO
Material
Electrolyte
Mass
rGO
VOx/rGO
Cell
Active
-
Hydrothermal
-
Solvothermal
5 mg
Hydrothermal
-
Spray Pyrolysis
-
Hydrothermal
20 mg
484
Capping Agent
(0.5 A g-1)
Co-Precipitation
-
configuretion (# of Electrodes)
8M LiCl 0.5M K2SO4 1M Na2SO4 0.5M K2SO4 0.5M K2SO4 0.5M K2SO4 1M LiTFSI 0.5M Na2SO4 1M Na2SO4 2M KCl 1M LiClO4 0.5 M K2SO4
3
2
2
3
3
4
2
5
3
6
3
7
2
8
3
9
3
10 11
3
12
2
13
3
14
466 rGO/V2O5
(2 mV s-1)
(Present Study)
450
Solvothermal
(0.5 A g-1)
S-8
2 mg
Ref.
1M Na2SO4
2
,
Table S2: Comparison of the lithium storage performance of this study with literature. Material
V2O5-rGO
V2O5-Graphene
Capacity (mAh g-1) 235 -1
(20 mA g ) 243 -1
(50 mA g )
Synthesis Method
Electrolyte
Hydrothermal
LiPF6
Slow Hydrolysis
1.2 M LiPF6
Sol-gel
1.2 M LiPF6
Solvothermal
1 M LiPF6
Synthetic Reaction
1 M LiPF6
Hydrothermal
1 M LiPF6
Additives
Ref.
1:1:1
15
(EC:DMC:DEC) 3:7
16
(EC:EMC)
+
V2O5-Graphene (2% Graphene)
V2O5/rGO
438 (3 Li insertion) (C/20) 211 -1
(190 mA g )
V2O5-Graphene
278
Nanoribbons
(C/10)
Graphene Oxide
240 -1
Coated V2O5
(100 mA g )
rGO-Enwrapped
287
V2O5 Nanorods V2O5 Nanocrystals on rGO Balls
Hydrothermal -1
(100 mA g ) 280 -1
(300 mA g )
V2O5 Nanowires-
225
rGO Composites
(C/5)
rGO-V2O5
295
(Present Study)
(31.3 mA g-1)
followed by Reflux
1 M LiPF6
Spray Pyrolysis
1 M LiPF6
Electrospinning
1 M LiPF6
Solvothermal
1 M LiPF6
S-9
3:7
17
(EC:EMC) 1:1
18
(EC:DMC) 1:1:1
19
(EC:DEC:DMC) 1:1:1
20
(EC:DEC:DMC) 1:1
21
(EC:DMC) 1:1
22
(EC:DMC) 1:1 (EC:DMC) 1:1:1 (EC:DMC:DEC)
23
Table S3: EIS fitting parameters of the LIB half-cell with a rGO-V2O5 cathode and a Li foil anode at different insertion (discharging) potentials. Potential (V) 3.2
Rs (ohm) 5.66
2.7
Ce
4.93E-4
Re (ohm) 22.13
2.55E-5
Rct (ohm) 36.18
0.539
5.46
5.38E-6
21.41
5.18E-5
47.32
0.478
2.4
5.48
5.37E-4
20.07
4.95E-5
45.37
0.437
2.2
5.47
3.86E-3
21.38
5.09E-6
40.67
0.372
(Ω-1sn)
Cdl
(Ω-1sn)
W
Table S4: EIS fitting parameters of the LIB half-cell with a rGO-V2O5 cathode and a Li foil anode at different extraction (charging) potentials. Potential (V) 2.4
Rs (ohm) 5.13
2.7
Ce
2.92E-6
Re (ohm) 25.53
3.74E-5
Rct (ohm) 56.65
0.325
5.45
4.22E-6
24.72
5.18E-5
43.08
0.408
3.2
5.65
5.37E-4
18.68
4.95E-5
36.51
0.487
3.5
5.63
4.23E-5
21.75
5.14E-6
32.91
0.800
(Ω-1sn)
S-10
Cdl
(Ω-1sn)
W
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