I have spectra from Raman analysis performed on a sample of graphite that I synthesized. This material will be used as an anode in a lithium-ion battery. This spectra gives a D/G ratio of about 0.1, with the G-band centered around 1577 cm-1. From most of the graphites that I have analyzed using Raman, a value for the D/G ratio of 0.1 is typical. However, my sample of graphite is exhibiting properties of graphene in the sense that the 2D peak is very rounded and symmetric. Because of the location of the G-band and the ratio of the D/G peaks, it seems clear that this is graphite. However, I am unsure as to how to interpret the meaning of a symmetric, fairly large 2D peak. I've attached a copy of the spectrum of my graphite, along with a commercially available graphite for reference (top one is the commercial graphite). Any information on the structure of the graphites and how I can determine differences between them besides a D/G ratio would be immensely helpful.
2D band shape, frequency and intensity are strongly influenced by not only the perfection of graphitic chemical structure but also by the number of graphite layers in the graphite nano platelet. See the following articles for specific influence of the number of layers on the 2D band shape, frequency and intensity.
Easy to read articles:
http://www.thermoscientific.com/content/dam/tfs/ATG/CAD/CAD%20Documents/Application%20%26%20Technical%20Notes/Molecular%20Spectroscopy/Raman/Raman%20Instruments/D19505~.pdf
http://www.thermoscientific.com/content/dam/tfs/ATG/CAD/CAD%20Documents/Application%20&%20Technical%20Notes/Molecular%20Spectroscopy/Raman/Raman%20Instruments/AN52252_E%201111%20LayerThkns_H_1.pdf
More scientific article:
http://www.asminternational.org/documents/10192/1878483/amp17004p35.pdf/5e8d2229-424d-4ece-a934-65f8c805f8e3/AMP17004P35
The presence of graphene can not be ruled out here. You need to investigate this further. However, what caught my eye is the fact that the spikes in the spectra occur almost at the same place in both spectra which is not expected.
2D band shape, frequency and intensity are strongly influenced by not only the perfection of graphitic chemical structure but also by the number of graphite layers in the graphite nano platelet. See the following articles for specific influence of the number of layers on the 2D band shape, frequency and intensity.
Easy to read articles:
http://www.thermoscientific.com/content/dam/tfs/ATG/CAD/CAD%20Documents/Application%20%26%20Technical%20Notes/Molecular%20Spectroscopy/Raman/Raman%20Instruments/D19505~.pdf
http://www.thermoscientific.com/content/dam/tfs/ATG/CAD/CAD%20Documents/Application%20&%20Technical%20Notes/Molecular%20Spectroscopy/Raman/Raman%20Instruments/AN52252_E%201111%20LayerThkns_H_1.pdf
More scientific article:
http://www.asminternational.org/documents/10192/1878483/amp17004p35.pdf/5e8d2229-424d-4ece-a934-65f8c805f8e3/AMP17004P35
Classical review article dedicated to G' (2D) is http://dx.doi.org/10.1016/j.physrep.2009.02.003
Did you ty different points on the sample surface?(I hope you have micro raman)
Probably you have graphene as a surface layer of the sample. The last layer may be weakly coupled to the surface. Try to remove the surface layer using scotch and repeat Raman measurements. But always do measurements in different points of the sample.
By which method, did you prepare graphite? Turbostratic graphite used to show a symmetric 2D band. XRD can also be used to provide more insight to the structure.
This link is really useful,
http://www.instanano.com/characterization/experimental/raman-graphene/
This link is worth reading to understand G and 2D band of graphene.
https://www.azom.com/article.aspx?ArticleID=6271
Dear Danny Ahumada,
in Graphene 2D peak can be deconvolution into some peaks which shows the number of layers of graphene. I have read many articles in this field and as I understood here the main problem with determining the intensity ratio of G and 2D.
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