Construction of hierarchical porous graphene–carbon nanotubes hybrid with high surface area for high performance supercapacitor applications
Dewei Wang,* Guoli Fang, Qian Zheng, Guihong Geng and Jinfu Ma
College of Materials Science and Engineering, Beifang University of Nationalities, Yinchuan, 750021, People’s Republic of China.
*Corresponding author. Tel: +86-951-2067378; E-mail: (D. Wang).
Fig. S1. Photographs of (a) GO-CNTs and (b) GO foam after freeze-drying.
Fig. S2. (a) a photograph of a piece of flake after pressing the as-obtained GO-CNTs foam at 0.3 Mpa, and (b) optical images of the product after laser reduction.
Detailed process for preparation of RGO-CNTs: The laser used in this work is a continuous wave semiconductor laser with wavelength of 808 nm and the output power can adjust between 0 and 2 W (Class Ⅳ laser product, Cautions: avoid eye/skin exposure to director scattered radiation!). The laser beam size is around 1.0 mm2 after focusing. The laser beam is directed towards the quartz tube and using a focusing lens to obtain a small irradiation area. The distance between the focusing lens and the quartz tube is 3.5 cm. In a typical laser reduction experiment, the laser power was 1 W, a piece of flake was put onto the quartz tube directly at ambient conditions, and the whole reaction process was very fast within 1 s upon laser irradiation. An intuition video can be seen from Video S1 (in supplementary data).
Fig. S3. Typical optical images describing process of the laser induced self-propagating reaction, (a) at the beginning of laser irradiation, (b), (c) during the laser irradiation, (d), (e) and (f) after the laser irradiation. From the corresponding time recording, it is obvious that the whole reaction time is less than 1 s. However, the exactly reaction time cannot be obtained because of the resolution limitations.
More detail information: The frontier of reaction is even red heat, indicating the reaction temperature is fairly high. It is believed that the extremely high temperature provided by the rapid local heating causes temperature to exceed that required for deoxygenate of the GO at the irradiated area, then the heat from the irradiated area transform to other directions of the GO to trigger deoxygenate reaction toward other position. Importantly, the ultrafast reaction process lead to the generation of large amount of gases, such as CO2, CO, and H2O rapidly, which exerted an outward force to overcome the van der Waals forces between the graphene sheets.
Fig. S4. (a) SEM and (b) TEM images of the LIGCTs.
Fig. S5. (a) SEM and (b) TEM images of the pristine CNTs.
Fig. S6. Cyclic voltammogram of the PGCTs electrode at the scan rate from 100 to 500 mV s–1.
Fig. S7. Cyclic voltammogram of the LIGCTs electrode at the scan rate from 5 to 50 mV s–1.
Fig. S8. Cyclic voltammogram of PGCTs, LIGCTs and LIG electrodes at a scan rate of 50 mV s–1.
Table S1. Comparison of the specific capacitance (Cs, F g−1) of some graphene based materials in the recent literatures.
Materials / electrolyte / Cs/current density (A g−1) / Electrode system / Ref.Graphene-CNTs / 1M H2SO4 / 251/2 / three / S1
porous graphene / 1M H2SO4 / 201/0.1 / two / S2
Porous B-doped graphene / 2M H2SO4 / 281/1 / three / S3
Graphene-CNTs / 6M KOH / 100/1 / two / S4
Non-Stacked Graphene / 6M KOH / 236./1 / two / S5
graphene paper / 2M KOH / 212/1 / three / S6
graphene/carbon nanotubes / 6M KOH / 167/1 / two / S7
planar graphene / 6M KOH / 96/1 / two / S8
Electrochemically reduced graphene / 1M H2SO4 / 246 / three / S9
graphene
oxide hydrogel / 2M KOH / 232/1 / two / S10
B-doped graphene / 6M KOH / 200/0.1 / two / S11
N-doped Graphene / 1M KCl / 182/0.5 / two / S12
N-doped Graphene / 6M KOH / 326/1 / three / S13
Graphene hydrogel / 5M KOH / 165/1 / two / S14
Graphene composite / 2M KOH / 236.7/1 / three / S15
N-doped Graphene / 6M KOH / 245.9/1 / three / S16
Graphene aerogel / 6M KOH / 128/0.05 / two / S17
graphene hydrogels / 1M H2SO4 / 258/0.3 / two / S18
PGCTs 6M KOH 310/0.5 two This work
References
S1. Zeng FY, Kuang YF, Zhang NS, Huang ZY, Pan Y, Hou ZH, Zhou HH, Yan CL, O. Schmidt G (2014) J Power Sources 247:396-401
S2. Gu Y, Wu H, Xiong ZG, Abdullab WA, Zhao XS (2014) J Mater Chem A 2:451–459
S3. Zuo ZC, Jiang ZQ, Manthiram A (2013) J Mater Chem A 1:13476–13483
S4. Yan Z, Ma LL, Zhu Y, Lahiri I, Hahm MG, Liu Z, Yang SB, Xiang CS, Lu W, Peng ZW, Sun ZZ, Kittrell C, Lou J, Choi WB, Ajayan PM, Tour JM (2013) ACS Nano 7:58-64
S5. Yoon Y, Lee K, Baik C, Yoo H, Min M, Park Y, Lee SM, Lee HY (2013) Adv Mater 25:4437–4444
S6. Sun DF, Yan XB, Lang JW, Xue QJ (2013) J Power Sources 222:52-58
S7. Wang Y, Wu YP, Huang Y, Zhang F, Yang X, Ma YF, Chen YS (2011) J Physi Chem C 115:23192–23197
S8. Zhang SL, Pan N (2013) J Mater Chem A 1:7957–7962
S9. Yu HW, He JJ, Sun L, Tanaka S, Fugetsu B (2013) Carbon 51:94-101
S10. Luan VH, Tien HN, Hoa LT, Nguyen H, Oh ES, Chung J, Choi WM, Kong BS, Hur SH (2013) J Mater Chem A 1:208–211
S11. Han J, Zhang LL, Lee S, Oh J, Lee KS, Potts JR, Ji JY, Zhao X, Ruoff RS, Park S (2013) ACS Nano 7:19-26
S12. Hassan FM, Chabot V, Li JD, Kim BK, Ricardez-Sandoval L, Yu AP (2013) J Mater Chem A 1:2904-2912
S13. Guo HL, Su P, Kang XF, Ning SK (2013) J Mater Chem A 1:2248-2255
S14. Xu YX, Sheng K, Li XC, Shi GQ (2010) ACS Nano 4:4324-4330
S15. Wang DW, Li YQ, Wang QH, Wang TM (2012) Eur J Inorg Chem 628-635
S16. Wen ZH, Wang XC, Mao S, Bo Z, Kim H, Cui SM, Lu GH, Feng XL, Chen JH (2012) Adv Mater 24:5610–5616
S17. Zhang XT, Sui ZY, Xu B, Yue SF, Luo YJ, Zhan WC, Liu B (2011) J Mater Chem 21:6494-6497
S18. Wu Q, Sun YQ, Bai H, Shi GQ (2011) Phys Chem Chem Phys 13:11193–11198
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