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Ultrahigh-throughput exfoliation of graphite into pristine ‘single-layer’ graphene using microwaves and molecularly engineered ionic liquids

Abstract

Graphene has shown much promise as an organic electronic material but, despite recent achievements in the production of few-layer graphene, the quantitative exfoliation of graphite into pristine single-layer graphene has remained one of the main challenges in developing practical devices. Recently, reduced graphene oxide has been recognized as a non-feasible alternative to graphene owing to variable defect types and levels, and attention is turning towards reliable methods for the high-throughput exfoliation of graphite. Here we report that microwave irradiation of graphite suspended in molecularly engineered oligomeric ionic liquids allows for ultrahigh-efficiency exfoliation (93% yield) with a high selectivity (95%) towards ‘single-layer’ graphene (that is, with thicknesses <1 nm) in a short processing time (30 minutes). The isolated graphene sheets show negligible structural deterioration. They are also readily redispersible in oligomeric ionic liquids up to ~100 mg ml–1, and form physical gels in which an anisotropic orientation of graphene sheets, once induced by a magnetic field, is maintained.

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Figure 1: Microwave-assisted liquid-phase exfoliation of graphite in ionic liquids.
Figure 2: Graphite exfoliation on microwave irradiation.
Figure 3: Microscopic visualization and analysis of isolated graphene sheets.
Figure 4: Structural integrity of isolated graphene sheets.
Figure 5: Physical properties of isolated graphene and its dispersion in IL2PF6.

References

  1. Novoselov, K. S. et al. Electric field effect in atomically thin carbon films. Science 306, 666–669 (2004).

    CAS  Google Scholar 

  2. Geim, A. K. & Novoselov, K. S. The rise of graphene. Nature Mater. 6, 183–191 (2007).

    Article  CAS  Google Scholar 

  3. Geim, A. K. Graphene: status and prospects. Science 324, 1530–1534 (2009).

    Article  CAS  Google Scholar 

  4. Novoselov, K. S. et al. A roadmap for graphene. Nature 490, 192–200 (2012).

    Article  CAS  Google Scholar 

  5. Mattevi, C., Kim, H. & Chhowalla, M. A review of chemical vapour deposition of graphene on copper. J. Mater. Chem. 21, 3324–3334 (2011).

    Article  CAS  Google Scholar 

  6. Nicolosi, V., Chhowalla, M., Kanatzidis, M. G., Strano, M. S. & Coleman, J. N. Liquid exfoliation of layered materials. Science 340, 1226419 (2013).

    Article  Google Scholar 

  7. Ciesielski, A. & Samorì, P. Graphene via sonication assisted liquid-phase exfoliation. Chem. Soc. Rev. 43, 381–398 (2014).

    Article  CAS  Google Scholar 

  8. Hernandez, Y. et al. High-yield production of graphene by liquid-phase exfoliation of graphite. Nature Nanotech. 3, 563–568 (2008).

    Article  CAS  Google Scholar 

  9. Lotya, M. et al. Liquid phase production of graphene by exfoliation of graphite in surfactant/water solutions. J. Am. Chem. Soc. 131, 3611–3620 (2009).

    Article  CAS  Google Scholar 

  10. Coleman, J. N. Liquid-phase exfoliation of nanotubes and graphene. Adv. Funct. Mater. 19, 3680–3695 (2009).

    Article  CAS  Google Scholar 

  11. Nuvoli, D. et al. High concentration few-layer graphene sheets obtained by liquid phase exfoliation of graphite in ionic liquid. J. Mater. Chem. 21, 3428–3431 (2011).

    Article  CAS  Google Scholar 

  12. Sampath, S. et al. Direct exfoliation of graphite to graphene in aqueous media with diazaperopyrenium dications. Adv. Mater. 25, 2740–2745 (2013).

    Article  CAS  Google Scholar 

  13. Liang, Y. T. & Hersam, M. C. Highly concentrated graphene solutions via polymer enhanced solvent exfoliation and iterative solvent exchange. J. Am. Chem. Soc. 132, 17661–17663 (2010).

    Article  CAS  Google Scholar 

  14. Wang, X. et al. Direct exfoliation of natural graphite into micrometre size few layers graphene sheets using ionic liquids. Chem. Commun. 46, 4487–4489 (2010).

    Article  CAS  Google Scholar 

  15. Ciesielski, A. et al. Harnessing the liquid-phase exfoliation of graphene using aliphatic compounds: a supramolecular approach. Angew. Chem. Int. Ed. 53, 10355–10361 (2014).

    Article  CAS  Google Scholar 

  16. Paton, K. R. et al. Scalable production of large quantities of defect-free few-layer graphene by shear exfoliation in liquids. Nature Mater. 13, 624–630 (2014).

    Article  CAS  Google Scholar 

  17. Zhao, W. et al. Preparation of graphene by exfoliation of graphite using wet ball milling. J. Mater. Chem. 20, 5817–5819 (2010).

    Article  CAS  Google Scholar 

  18. Rangappa, D. et al. Rapid and direct conversion of graphite crystals into high-yielding, good-quality graphene by supercritical fluid exfoliation. Chem. Eur. J. 16, 6488–6494 (2010).

    Article  CAS  Google Scholar 

  19. Shih, C. J. et al. Bi- and trilayer graphene solutions. Nature Nanotech. 6, 439–445 (2011).

    Article  CAS  Google Scholar 

  20. Wei, T., Fan, Z., Luo, G., Zheng, C. & Xie, D. A rapid and efficient method to prepare exfoliated graphite by microwave irradiation. Carbon 47, 337–339 (2008).

    Article  Google Scholar 

  21. Kovtyukhova, N. I. et al. Non-oxidative intercalation and exfoliation of graphite by Brønsted acids. Nature Chem. 6, 957–963 (2014).

    Article  CAS  Google Scholar 

  22. Parvez, K. et al. Exfoliation of graphite into graphene in aqueous solutions of inorganic salts. J. Am. Chem. Soc. 136, 6083–6091 (2014).

    Article  CAS  Google Scholar 

  23. Zhu, Y. et al. Graphene and graphene oxide: synthesis, properties, and applications. Adv. Mater. 22, 3906–3924 (2010).

    Article  CAS  Google Scholar 

  24. Dreyer, D. R., Park, S., Bielawski, C. W. & Ruoff, R. S. The chemistry of graphene oxide. Chem. Soc. Rev. 39, 228–240 (2010).

    Article  CAS  Google Scholar 

  25. Zhu, Y. et al. Microwave assisted exfoliation and reduction of graphite oxide for ultracapacitors. Carbon 48, 2118–2122 (2010).

    Article  CAS  Google Scholar 

  26. Bianco, A. et al. All in the graphene family—a recommended nomenclature for two-dimensional carbon materials. Carbon 65, 1–6 (2013).

    Article  CAS  Google Scholar 

  27. Wick, P. et al. Classification framework for graphene-based materials. Angew. Chem. Int. Ed. 53, 7714–7718 (2014).

    Article  CAS  Google Scholar 

  28. Qin, F. & Brosseau, C. A review and analysis of microwave absorption in polymer composites filled with carbonaceous particles. J. Appl. Phys. 111, 061301 (2012).

    Article  Google Scholar 

  29. Wang, C. et al. The electromagnetic property of chemically reduced graphene oxide and its application as microwave absorbing material. Appl. Phys. Lett. 98, 072906 (2011).

    Article  Google Scholar 

  30. Tang, J., Radosz, M. & Shen, Y. Poly(ionic liquid)s as optically transparent microwave-absorbing materials. Macromolecules 41, 493–496 (2008).

    Article  CAS  Google Scholar 

  31. Robinson, J. et al. Understanding microwave heating effects in single mode type cavities—theory and experiment. Phys. Chem. Chem. Phys. 12, 4750–4758 (2010).

    Article  CAS  Google Scholar 

  32. Fukushima, T. et al. Molecular ordering of organic molten salts triggered by single-walled carbon nanotubes. Science 300, 2072–2074 (2003).

    Article  CAS  Google Scholar 

  33. Lee, J. & Aida, T. ‘Bucky gels’ for tailoring electroactive materials and devices the composites of carbon materials with ionic liquids. Chem. Commun. 47, 6757–6762 (2011).

    Article  CAS  Google Scholar 

  34. Ma, J. C. & Dougherty, D. A. The cation−π interaction. Chem. Rev. 97, 1303–1324 (1997).

    Article  CAS  Google Scholar 

  35. Jia, X. et al. Graphene edges: a review of their fabrication and characterization. Nanoscale 3, 86–95 (2011).

    Article  CAS  Google Scholar 

  36. Shim, J. et al. Water-gated charge doping of graphene induced by mica substrates. Nano Lett. 12, 648–654 (2012).

    Article  CAS  Google Scholar 

  37. Ochedowski, O., Bussmann, B. K. & Schleberger, M. Graphene on mica—intercalated water trapped for life. Sci. Rep. 4, 6003 (2014).

    Article  CAS  Google Scholar 

  38. Ferrari, A. C. et al. Raman spectrum of graphene and graphene layers. Phys. Rev. Lett. 97, 187401 (2006).

    Article  CAS  Google Scholar 

  39. Lucchese, M. M. et al. Quantifying ion-induced defects and Raman relaxation length in graphene. Carbon 48, 1592–1597 (2010).

    Article  CAS  Google Scholar 

  40. Bae, S. et al. Roll-to-roll production of 30-inch graphene films for transparent electrodes. Nature Nanotech. 5, 574–578 (2010).

    Article  CAS  Google Scholar 

  41. Fasting, C. et al. Multivalency as a chemical organization and action principle. Angew. Chem. Int. Ed. 51, 10472–10498 (2012).

    Article  CAS  Google Scholar 

  42. Vadahanambi, S., Jung, J. H., Kumar, R., Kim, H. J. & Oh, I. K. An ionic liquid-assisted method for splitting carbon nanotubes to produce graphene nano-ribbons by microwave radiation. Carbon 53, 391–398 (2013).

    Article  CAS  Google Scholar 

  43. Rüdorff, W. & Rüdorff, G. Zur Konstitution des Kohlenstoff. Mononuorids. Z. Anorg. Allg. Chem. 253, 281–296 (1947).

    Article  Google Scholar 

  44. Mallouk, T. & Bartlett, N. Reversible intercalation of graphite by fluoride: a new bifluoride, C12HF2, and graphite CxF (5 &gt; x &gt; 2). J. Chem. Soc. Chem. Commun. 103–105 (1983).

  45. Behabtu, N. et al. Spontaneous high-concentration dispersions and liquid crystals of graphene. Nature Nanotech. 5, 406–411 (2010).

    Article  CAS  Google Scholar 

  46. Alzari, V. et al. Graphene-containing thermoresponsive nanocomposite hydrogels of poly(N-isopropylacrylamide) prepared by frontal polymerization. J. Mater. Chem. 21, 8727–8733 (2011).

    Article  CAS  Google Scholar 

  47. Stamenov, P. & Coey, J. M. D. Magnetic susceptibility of carbon—experiment and theory. J. Magnet. Magn. Mater. 290–291, 279–285 (2005).

    Article  Google Scholar 

  48. Wu, L. et al. Magnetically induced anisotropic orientation of graphene oxide locked by in situ hydrogelation. ACS Nano 8, 4640–4649 (2014).

    Article  CAS  Google Scholar 

  49. Fuller, J., Carlin, R. T., De Long, H. C. & Haworth, D. Structure of 1-ethyl-3-methylimidazolium hexafluorophosphate: model for room temperature molten salts. J. Chem. Soc. Chem. Commun. 299–300 (1994).

  50. Wilkes, J. S. & Zaworotko, M. J. Air and water stable 1-ethyl-3-methylimidazolium based ionic liquids. J. Chem. Soc. Chem. Commun. 965–967 (1992).

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Acknowledgements

We acknowledge the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Specially Promoted Research on the Physically Perturbed Assembly for Tailoring High-Performance Soft Materials with Controlled Macroscopic Structural Anisotropy (25000005) and the JSPS FIRST Program for Innovative Basic Research Toward the Creation of a High-performance Battery. We thank E. Silver for generous discussion. SEM, TEM and XPS were conducted at the Research Hub for Advanced Nano Characterization, The University of Tokyo, supported by the Ministry of Education, Culture, Sports, Science and Technology, Japan. We also acknowledge the ImPACT Program of the Council for Science, Technology and Innovation (Cabinet Office, Government of Japan).

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M.M. and Y.S. designed and performed all the experiments. C.P., T.F. and T.A. co-designed the experiments. M.M. and T.A. analysed the data and wrote the manuscript.

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Correspondence to Takuzo Aida.

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Matsumoto, M., Saito, Y., Park, C. et al. Ultrahigh-throughput exfoliation of graphite into pristine ‘single-layer’ graphene using microwaves and molecularly engineered ionic liquids. Nature Chem 7, 730–736 (2015). https://doi.org/10.1038/nchem.2315

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