This study was focused on the understanding of the electrochemical exfoliation in graphene. This experiment field was divided by two, first is electrochemical exfoliation of graphite. By controlling the time duration and applied voltage could be able to reduce the defectiveness in graphene. Applied voltage was set for 2, 3, and 4 V as the static potential and sequences apply a high voltage between +10V to -10V. The electrochemical exfoliation duration was set for 1, 2, and 3 hours to every parameter. The obtained graphene powder showed a random result that cannot get a clear trend about are longer exfoliation or higher applied voltage which gave a good quality graphene. Based on those result, then the experiment going approach to get deeply understanding about electrochemical exfoliation graphene using bi-layer graphene which is ad-layer graphene.
Electrochemical exfoliation of ad-layer graphene was characterized using high-quality measurement tools to study the electrochemical behavior of graphene and using raman and raman mapping before and after electrochemical exfoliation process to investigate the defectiveness of the graphene. The ad-layer graphene was prepared two different samples, first is ad-layer and the second one is flip ad-layer to find where the ad-layer island was growth, either on the top side or in underneath. The efficient exfoliation graphene obtained using flip ad-layer which means underneath side of ad-layer graphene had more ad-layer than on the top side. Showed that flip ad-layer has higher capacitance than ad-layer. The capacitance value of ad-layer sample is 4.67E-09 Farad, and the flip ad-layer sample is 3.59E-08 Farad

REFERENCE

[1] M. Pumera, "Graphene-based nanomaterials for energy storage," Energy & Environmental Science, vol. 4, pp. 668-674, 2011.
[2] Y. Wang, Z. Shi, Y. Huang, Y. Ma, C. Wang, M. Chen, et al., "Supercapacitor devices based on graphene materials," The Journal of Physical Chemistry C, vol. 113, pp. 13103-13107, 2009.
[3] A. R. Yusoff, Graphene-Based Energy Devices: Wiley-VCH Verlag GmbH, 2015.
[4] G. M. Morales, P. Schifani, G. Ellis, C. Ballesteros, G. Martínez, C. Barbero, et al., "High-quality few layer graphene produced by electrochemical intercalation and microwave-assisted expansion of graphite," Carbon, vol. 49, pp. 2809-2816, 7// 2011.
[5] C.-Y. Yang, C.-L. Wu, Y.-H. Lin, L.-H. Tsai, Y.-C. Chi, J.-H. Chang, et al., "Fabricating graphite nano-sheet powder by slow electrochemical exfoliation of large-scale graphite foil as a mode-locker for fiber lasers," Optical Materials Express, vol. 3, pp. 1893-1905, 2013/11/01 2013.
[6] M. Inagaki, F. Kang, M. Toyoda, and H. Konno, "Chapter 3 - Graphene: Synthesis and Preparation," in Advanced Materials Science and Engineering of Carbon, ed Boston: Butterworth-Heinemann, 2014, pp. 41-65.
[7] K. Parvez, Z.-S. Wu, R. Li, X. Liu, R. Graf, X. Feng, et al., "Exfoliation of graphite into graphene in aqueous solutions of inorganic salts," Journal of the American Chemical Society, vol. 136, pp. 6083-6091, 2014.
[8] T.-W. Chen, Y.-P. Hsieh, and M. Hofmann, "Ad-layers enhance graphene's performance," RSC Advances, vol. 5, pp. 93684-93688, 2015.
[9] W. Choi and J.-w. Lee, Graphene: Synthesis and applications: CRC Press, 2011.
[10] A. K. Geim and K. S. Novoselov, "The rise of graphene," Nature materials, vol. 6, pp. 183-191, 2007.
[11] M. Pumera, "Electrochemistry of graphene: new horizons for sensing and energy storage," The Chemical Record, vol. 9, pp. 211-223, 2009.
[12] Y. Zhu, S. Murali, W. Cai, X. Li, J. Suk, J. Potts, et al., "Graphene and Graphene Oxide: Synthesis, Properties, and Applications," Advanced materials, vol. 22, pp. 3906-3924, 2010.
[13] C.-J. Shih, A. Vijayaraghavan, R. Krishnan, R. Sharma, J.-H. Han, M.-H. Ham, et al., "Bi-and trilayer graphene solutions," Nature nanotechnology, vol. 6, pp. 439-445, 2011.
[14] W. Choi, I. Lahiri, R. Seelaboyina, and Y. S. Kang, "Synthesis of graphene and its applications: a review," Critical Reviews in Solid State and Materials Sciences, vol. 35, pp. 52-71, 2010.
[15] K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, et al., "Electric Field Effect in Atomically Thin Carbon Films," Science, vol. 306, p. 666, 2004.
[16] Y. Hernandez, V. Nicolosi, M. Lotya, F. M. Blighe, Z. Sun, S. De, et al., "High-yield production of graphene by liquid-phase exfoliation of graphite," Nat Nano, vol. 3, pp. 563-568, 09//print 2008.
[17] M. Yi and Z. Shen, "A review on mechanical exfoliation for the scalable production of graphene," Journal of Materials Chemistry A, vol. 3, pp. 11700-11715, 2015.
[18] K. E. Whitener Jr and P. E. Sheehan, "Graphene synthesis," Diamond and Related Materials, vol. 46, pp. 25-34, 6// 2014.
[19] V. Singh, D. Joung, L. Zhai, S. Das, S. I. Khondaker, and S. Seal, "Graphene based materials: Past, present and future," Progress in Materials Science, vol. 56, pp. 1178-1271, 10// 2011.
[20] S. Nie, A. L. Walter, N. C. Bartelt, E. Starodub, A. Bostwick, E. Rotenberg, et al., "Growth from Below: Graphene Bilayers on Ir(111)," ACS Nano, vol. 5, pp. 2298-2306, 2011/03/22 2011.
[21] L. Beneš, K. Melánová, V. Zima, J. Kalousová, and J. Votinský, "Possible Mechanisms of Intercalation," Journal of inclusion phenomena and molecular recognition in chemistry, vol. 31, pp. 275-286, 1998.
[22] "Front Matter A2 - Inagaki, Michio," in Advanced Materials Science and Engineering of Carbon, F. Kang, M. Toyoda, and H. Konno, Eds., ed Boston: Butterworth-Heinemann, 2014, p. iii.
[23] M. Dresselhaus and G. Dresselhaus, "Intercalation compounds of graphite," Advances in Physics, vol. 30, pp. 139-326, 1981.
[24] M. Inagaki, Y. A. Kim, and M. Endo, "Graphene: preparation and structural perfection," Journal of Materials Chemistry, vol. 21, pp. 3280-3294, 2011.
[25] A. Hamra, H. Lim, W. Chee, and N. Huang, "Electro-exfoliating graphene from graphite for direct fabrication of supercapacitor," Applied Surface Science, vol. 360, pp. 213-223, 2016.
[26] M. Hofmann, W.-Y. Chiang, T. D. Nguyễn, and Y.-P. Hsieh, "Controlling the properties of graphene produced by electrochemical exfoliation," Nanotechnology, vol. 26, p. 335607, 2015.
[27] J. Liu, H. Yang, S. Zhen, C. Poh, A. Chaurasia, J. Luo, et al., "A green approach to the synthesis of high-quality graphene oxide flakes via electrochemical exfoliation of pencil core," RSC Advances, vol. 3, p. 11745, 2013.
[28] C. Low, F. Walsh, M. Chakrabarti, M. Hashim, and M. Hussain, "Electrochemical approaches to the production of graphene flakes and their potential applications," Carbon, vol. 54, pp. 1-21, 2013.
[29] J. Hui, M. Burgess, J. Zhang, and J. Rodríguez-López, "Layer Number Dependence of Li+ Intercalation on Few-Layer Graphene and Electrochemical Imaging of Its Solid–Electrolyte Interphase Evolution," ACS Nano, vol. 10, pp. 4248-4257, 2016/04/26 2016.
[30] R. Raccichini, A. Varzi, S. Passerini, and B. Scrosati, "The role of graphene for electrochemical energy storage," Nature materials, vol. 14, pp. 271-279, 2015.
[31] Y. Geng, Q. Zheng, and J.-K. Kim, "Effects of stage, intercalant species and expansion technique on exfoliation of graphite intercalation compound into graphene sheets," Journal of nanoscience and nanotechnology, vol. 11, pp. 1084-1091, 2011.
[32] M. Li, Q. Gu, W. Han, X. Zhang, Y. Sun, M. Zhang, et al., "Electrochemical behavior of La (iii) on liquid Bi electrode in LiCl–KCl melts. Determination of thermodynamic properties of La–Bi and Li–Bi intermetallic compounds," RSC Advances, vol. 5, pp. 82471-82480, 2015.
[33] Y. Ko, Y.-G. Cho, and H.-K. Song, "Programming galvanostatic rates for fast-charging lithium ion batteries: a graphite case," RSC Advances, vol. 4, pp. 16545-16550, 2014.
[34] N. Iwashita and M. Inagaki, "Intercalation of Sulfuric Acid into Graphite -Followed by Potential Measurement," NIPPON KAGAKU KAISHI, vol. 1992, pp. 1412-1422, 1992.
[35] M. Inagaki, N. Iwashita, and E. Kouno, "Potential change with intercalation of sulfuric acid into graphite by chemical oxidation," Carbon, vol. 28, pp. 49-55, 1990.
[36] F. Kang, T.-Y. Zhang, and Y. Leng, "Electrochemical synthesis of sulfate graphite intercalation compounds with different electrolyte concentrations," Journal of Physics and Chemistry of Solids, vol. 57, pp. 883-888, 1996/06/01 1996.
[37] D. A. Brownson and C. E. Banks, The handbook of graphene electrochemistry: Springer, 2014.
[38] M. Pumera, "Graphene-based nanomaterials and their electrochemistry," Chemical Society Reviews, vol. 39, pp. 4146-4157, 2010.
[39] B.-Y. Chang and S.-M. Park, "Electrochemical impedance spectroscopy," Annual Review of Analytical Chemistry, vol. 3, pp. 207-229, 2010.
[40] M. S. Goh and M. Pumera, "Multilayer graphene nanoribbons exhibit larger capacitance than their few-layer and single-layer graphene counterparts," Electrochemistry Communications, vol. 12, pp. 1375-1377, 10// 2010.
[41] A. Das, B. Chakraborty, and A. Sood, "Raman spectroscopy of graphene on different substrates and influence of defects," Bulletin of Materials Science, vol. 31, pp. 579-584, 2008.
[42] A. C. Ferrari, J. C. Meyer, V. Scardaci, C. Casiraghi, M. Lazzeri, F. Mauri, et al., "Raman Spectrum of Graphene and Graphene Layers," Physical Review Letters, vol. 97, p. 187401, 10/30/ 2006.
[43] C.-Y. Su, A.-Y. Lu, Y. Xu, F.-R. Chen, A. N. Khlobystov, and L.-J. Li, "High-quality thin graphene films from fast electrochemical exfoliation," ACS nano, vol. 5, pp. 2332-2339, 2011.
[44] C.-H. Chen, S.-W. Yang, M.-C. Chuang, W.-Y. Woon, and C.-Y. Su, "Towards the continuous production of high crystallinity graphene via electrochemical exfoliation with molecular in situ encapsulation," Nanoscale, vol. 7, pp. 15362-15373, 2015.
[45] R. Sharma, J. H. Baik, C. J. Perera, and M. S. Strano, "Anomalously Large Reactivity of Single Graphene Layers and Edges toward Electron Transfer Chemistries," Nano Letters, vol. 10, pp. 398-405, 2010/02/10 2010.
[46] V. A. Sethuraman, L. J. Hardwick, V. Srinivasan, and R. Kostecki, "Surface structural disordering in graphite upon lithium intercalation/deintercalation," Journal of Power Sources, vol. 195, pp. 3655-3660, 2010.
[47] L. J. Hardwick, P. W. Ruch, M. Hahn, W. Scheifele, R. Kötz, and P. Novák, "In situ Raman spectroscopy of insertion electrodes for lithium-ion batteries and supercapacitors: First cycle effects," Journal of Physics and Chemistry of Solids, vol. 69, pp. 1232-1237, 2008.
[48] T. Piao, S. M. Park, C. H. Doh, and S. I. Moon, "Intercalation of lithium ions into graphite electrodes studied by AC impedance measurements," Journal of The Electrochemical Society, vol. 146, pp. 2794-2798, 1999.
[49] L. Tian, Q. Zhuang, J. Li, Y. Shi, J. Chen, F. Lu, et al., "Mechanism of intercalation and deintercalation of lithium ions in graphene nanosheets," Chinese Science Bulletin, vol. 56, pp. 3204-3212, 2011.
[50] C. Wang, A. J. Appleby, and F. E. Little, "Electrochemical impedance study of initial lithium ion intercalation into graphite powders," Electrochimica acta, vol. 46, pp. 1793-1813, 2001.
[51] C. Yang, J. Song, Y. Wang, and C. Wan, "Impedance spectroscopic study for the initiation of passive film on carbon electrodes in lithium ion batteries," Journal of applied electrochemistry, vol. 30, pp. 29-34, 2000.
[52] Y. Soneda, J. Yamashita, M. Kodama, H. Hatori, M. Toyoda, and M. Inagaki, "Pseudo-capacitance on exfoliated carbon fiber in sulfuric acid electrolyte," Applied Physics A, vol. 82, pp. 575-578, 2006.
[53] M. Acik, C. Mattevi, C. Gong, G. Lee, K. Cho, M. Chhowalla, et al., "The Role of Intercalated Water in Multilayered Graphene Oxide," ACS nano, vol. 4, pp. 5861-5868, 2010.
[54] G. Bussetti, R. Yivlialin, D. Alliata, A. Li Bassi, C. Castiglioni, M. Tommasini, et al., "Disclosing the Early Stages of Electrochemical Anion Intercalation in Graphite by a Combined Atomic Force Microscopy/Scanning Tunneling Microscopy Approach," The Journal of Physical Chemistry C, vol. 120, pp. 6088-6093, 2016.
[55] M. D. Levi and D. Aurbach, "Simultaneous Measurements and Modeling of the Electrochemical Impedance and the Cyclic Voltammetric Characteristics of Graphite Electrodes Doped with Lithium," The Journal of Physical Chemistry B, vol. 101, pp. 4630-4640, 1997/06/01 1997.
[56] J. Skowroński, "Electrochemical intercalation of sulphuric acid into graphite in the presence of molybdenum trioxide," Solid state ionics, vol. 157, pp. 51-55, 2003.
[57] H. Shioyama and R. Fujii, "Electrochemical reactions of stage 1 sulfuric acid—Graphite intercalation compound," Carbon, vol. 25, pp. 771-774, 1987/01/01 1987.
[58] J. M. Skowroński and K. Jurewicz, "Anodic oxidation of CrO3-graphite intercalation compounds in sulfuric acid," Synthetic Metals, vol. 40, pp. 161-172, 1991/04/01 1991.
[59] A. Funabiki, M. Inaba, T. Abe, and Z. Ogumi, "Stage Transformation of Lithium‐Graphite Intercalation Compounds Caused by Electrochemical Lithium Intercalation," Journal of The Electrochemical Society, vol. 146, pp. 2443-2448, 1999.