Fluorination of Multi-Layered Carbon Nanomaterials

Abstract

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 . 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 ratio 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, multi-layered carbon nanofibers, carbon nanowhiskers and carbon nanorods. 
     
     
         2 . The material of  claim 1 , wherein the carbon nanomaterial is selected from multiwalled carbon nanotubes and multi-layered carbon nanofibers. 
     
     
         3 . The material of  claim 2 , wherein the carbon nanomaterial is a carbon nanofiber having a diameter between 40 nm and 1000 nm. 
     
     
         4 . The material of  claim 2 , 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. 
     
     
         5 . The material of  claim 2 , wherein the average ratio of fluorine to carbon is 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. 
     
     
         6 . The material of  claim 2 , wherein the carbon nanomaterial is a multiwalled carbon nanotube having a diameter greater than 10 nm. 
     
     
         7 . The material of  claim 1 , wherein the average ratio of fluorine to carbon is between 0.6 and 0.8. 
     
     
         8 . The material of  claim 4 , 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. 
     
     
         9 . The material of  claim 8 , wherein the average ratio of fluorine to carbon is between 0.39 and 0.68. 
     
     
         10 . The material 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. 
     
     
         11 . The material of  claim 10 , wherein the average ratio of carbon to fluorine is between 0.68 and 0.86. 
     
     
         12 . A method for fluorinating a multi-layered carbon nanomaterial comprising the step of exposing the carbon nanomaterial to a gaseous source of elemental fluorine at a pressure between 1 atm and 0.1 atm at a temperature between 400° C. and 475° C. for a time between 4 and 20 hours, wherein the carbon nanomaterial has a substantially ordered multi-layered structure prior to fluorination, the layers of carbon are non-planar, and the carbon nanomaterial is selected from the group consisting of multiwalled carbon nanotubes, multi-layered carbon nanofibers, carbon nanowhiskers and carbon nanorodss. 
     
     
         13 . The method of  claim 12 , wherein the gaseous source of elemental fluorine comprises a mixture of fluorine and an inert gas. 
     
     
         14 . The method of  claim 12 , wherein the temperature is in the range of 420° C/-465° C. 
     
     
         15 . The method of  claim 12 , wherein the time is in the range between 8 and 16 hours. 
     
     
         16 . The method of  claim 12 , wherein the pressure is between 1 and 0.25 atm. 
     
     
         17 . The method of  claim 12 , wherein the diameter of the carbon nanomaterial is between 40 nm and 1000 nm. 
     
     
         18 . The method of  claim 12 , wherein the diameter of the carbon nanomaterial is between 80 nm and 350 nm. 
     
     
         19 . The method of  claim 12 , 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. 
     
     
         20 . The method of  claim 12 , wherein the average ratio of fluorine to carbon of the fluorinated carbon nanomaterial is between 0.39 and 0.95 and 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.