Fluorination of multi-layered carbon nanomaterials
The invention provides fluorinated multi-layered carbon nanomaterials and methods for their production. In one aspect of the invention, the carbon nanomaterials are partially fluorinated and retain some unreacted carbon. The invention also provides electrodes and electrochemical devices incorporating the fluorinated carbon nanomaterials of the invention. In one aspect of the invention, the electrochemical has a first electrode including the at least partially fluorinated carbon materials of the invention and a second electrode including a source of lithium ions.
1. An electrochemical device comprising a first electrode, a second electrode, and an ion transporting material disposed therebetween, wherein the first electrode comprises a fluorinated carbon nanomaterial obtained by direct fluorination of a carbon nanomaterial, the fluorinated carbon nanomaterial comprising a fluorination product which includes carbon atoms covalently bound to fluorine atoms and having an average chemical composition CF x wherein x is the atomic ration of fluorine to carbon and has a value between 0.39 and 0.95, wherein the carbon nanomaterial has a substantially ordered multi-layered structure prior to fluorination, the layers of carbon being non-planar, and the carbon nanomaterial is selected from the group consisting of multiwalled carbon nanotubes and multi-layered carbon nanofibers.
2. The device of claim 1 , wherein the carbon nanomaterial is a carbon nanofiber having a diameter between 40 nm and 1000 nm.
3. The device of claim 1 , wherein the average ratio of fluorine to carbon is between 0.39 and 0.86 and the fluorination product further includes sp 3 carbon atoms covalently bound to carbon atoms.
4. The device of claim 1 , wherein the average ratio of fluorine to carbon is between from 0.59 to 0.86, the material includes a second fluorination product in which carbon is non-covalently bound to fluorine and the first fluorination product further includes sp 3 carbon atoms covalently bound to carbon atoms.
5. The material of claim 1 , wherein the carbon nanomaterial is a multiwalled carbon nanotube having a diameter greater than 10 nm.
6. The device of claim 1 , wherein the average ratio of fluorine to carbon is between 0.6 and 0.8.
7. The device of claim 3 , wherein the fluorinated carbon nanomaterial comprises an unfluorinated carbon phase, wherein the unfluorinated carbon phase displays an x-ray diffraction peak in the 24.6-26.6 degrees angle range using a Cu K α radiation source.
8. The device of claim 1 , wherein the fluorinated carbon nanomaterial is in a composition further comprising a conductive diluent and a binder.
9. The device of claim 8 , wherein the conductive diluent is selected from the group consisting of acetylene black, carbon black, powdered graphite, cokes, carbon fibers, metallic powders, and combinations thereof.
10. The device of claim 8 , wherein the binder is polymeric.
11. The device of claim 10 , wherein the binder is a fluorinated hydrocarbon polymer.
12. The device of claim 1 , wherein the second electrode comprises a source of ions of a metal selected from Groups 1, 2, and 3 of the Periodic Table of Elements.
13. The device of claim 12 , wherein the ions are lithium ions.
14. The device of claim 13 , wherein the source of lithium ions is selected from the group consisting of lithium metal, a lithium alloy, and a carbon-lithium material.
15. The device of claim 14 , wherein the source of lithium ions is lithium metal or a lithium alloy.
16. The device of claim 1 , wherein the ion-transporting material physically separates the first and the second electrode and prevents direct electrical contact therebetween.
17. The device of claim 16 , wherein the ion-transporting material comprises a polymeric material and a nonaqueous electrolyte.
18. The device of claim 7 , wherein the average ratio of fluorine to carbon is between 0.39 and 0.68.
19. The device of claim 1 , wherein the fluorinated material displays a) an X-ray diffraction peak in the 9.8-15 degrees angle range, b) a 19 F NMR peak in the range between (−180) ppm and (−200) ppm/CFCl 3 , and c) three 13 C NMR peaks: a first peak in the 100-150 ppm/TMS range, a second peak in the 84-88 ppm/TMS range and a third peak in the 42-48 ppm/TMS range.
20. The device of claim 19 , wherein the average ratio of carbon to fluorine is between 0.68 and 0.86.