Preparation and Characteristics of Highly Expandable Graphite Intercalation Compounds by Two-Step Chemical Intercalation

Abstract:

Graphite intercalation compounds (GIC) are the most common precursors for expanded graphites which are promising materials for many applications. A series of GICs with different expanding volumes (EV) were prepared by a two-step chemical intercalation way. Effects of the input of oxidant and intercalating agent on the EV of GICs were discussed. The microstructures and morphologies of graphites before and after intercalation were analylized by X-ray diffraction and scanning electron microscope, respectively. The results show that the GIC with an EV of 600 ml⋅g^-1 may be prepared under temperal conditions by a two-step intercalation way. The interlayer spacing of the pre-GIC formeded by one-step intercalation is a bit larger than that of natural graphites, while the interlayer spacing of the GIC obtained by two-step intercalation becomes much larger than that of the pre-GIC because of secondery intercalation. When the d-spacing (d₀₀₂) value of the GIC rises from 0.3590 nm up to 0.3711nm, its EV increases from 267 up to 600 ml⋅g^-1 due to the decomposition and release of much more intercalated substances during a thermal shock.

• Periodical: Key Engineering Materials (Volume 703)
• Pages: 278-283
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.703.278
• Online since: August 2016
• Authors: Xiao Xia Li*, Ji Jin Zhao, De Yue Ma
• Keywords: Expanded Graphite, Expanding Volume, Graphite Intercalation Compound, Intercalation

References

[1] Chung D. D Flexible graphite for gasketing, adsorption, electromagnetic interference shielding, vibration damping, electrochemical applications, and stress sensing[J]. J Mater Eng Perform, 9 (2000) 161-163.

DOI: 10.1361/105994900770346105

[2] Grayfer ED, Nazarov AS, Makotchenko VG, et al. Chemically modified graphene sheets by functionalization of highly expanded graphite [J]. J Mater Chem, 21 (2011) 3410-3414.

DOI: 10.1039/c0jm02469d

[3] Li Jihui, Liu Qian, Da Huifang. Preparation of sulfur-free expanded graphite at a low exfoliation temperature[J]. Mater Lett, 61 (2007) 1832-1834.

DOI: 10.1016/j.matlet.2006.07.142

[4] Wei Xinghai, Liu Lang, Zhang Jinxi, et al. The preparation and morphology characteristics of exfoliated graphite derived from HClO4-graphite intercalation compounds [J]. Materials Letters, 64 (2010) 1007-1009.

DOI: 10.1016/j.matlet.2009.11.025

[5] Saidaminov MI, Maksimova NV, Sorokina NE, et al. Effect of graphite nitrate exfoliation conditions on the released gas composition and properties of expanded graphite [J]. Inorg Mater, 49 (2013) 883-888.

DOI: 10.1134/s0020168513090161

[6] Viktor G. Makotchenko, Ekaterina D. Grayfer, et al. The synthesis and properties of highly exfoliated graphites from fluorinated graphite intercalation compounds. Carbon, 49 (2011) 3233-3241.

DOI: 10.1016/j.carbon.2011.03.049

[7] Zhao Jijin, Li Xiaoxia, Guo Yuxiang, et al. Effect of expanding volume of expanded graphite on infrared screening performance [J]. Infrared and Laser Engineering, 43 (2014) 434-437.

[8] Zhao Jijin, Li Xiaoxia, Guo Yuxiang, et al. Preparation and microstructure of two kinds of expanded graphite[J]. Adv Mater Res, 2013, (706-708): 211-214.