Subfluorinated graphite fluorides as electrode materials
Subfluorinated graphite fluorides of formula CF x , wherein x is in the range of 0.06 to 0.63, e.g., 0.10 to 0.46, are used as electrode materials in electrochemical devices that convert chemical energy to electrical current, e.g., batteries. The invention additionally provides methods of manufacturing electrodes with the subfluorinated graphite fluorides, as well as primary and secondary batteries containing such electrodes.
1 . An electrochemical device comprising an anode, a cathode, and an ion-transporting material therebetween, wherein the cathode comprises a subfluorinated graphite fluoride of formula CF x in which x is in the range of 0.06 to 0.63.
2 . The device of claim 1 , wherein x is in the range of 0.06 to 0.52.
3 . The device of claim 2 , wherein x is in the range of 0.10 to 0.52.
4 . The device of claim 3 , wherein x is in the range of 0.10 to 0.46.
5 . The device of claim 4 , wherein x is in the range of 0.33 to 0.46.
6 . The device of claim 1 , wherein the subfluorinated graphite fluoride comprises a particulate material.
7 . The device of claim 6 , wherein the subfluorinated graphite fluoride has an average particle size in the range of about 1 micron to about 10 microns.
8 . The device of claim 7 , wherein the subfluorinated graphite fluoride has an average particle size in the range of about 4 microns to about 7.5 microns.
9 . The device of claim 8 , wherein the subfluorinated graphite fluoride has an average particle size of about 4 microns.
10 . The device of claim 1 , wherein the subfluorinated graphite fluoride is in a composition further comprising a conductive diluent and a binder.
11 . The device of claim 10 , wherein the conductive diluent is selected from acetylene black, carbon black, powdered graphite, cokes, carbon fibers, metallic powders, and combinations thereof.
12 . The device of claim 11 , wherein the conductive diluent is acetylene black.
13 . The device of claim 10 , wherein the binder is polymeric.
14 . The device of claim 13 , wherein the binder is a fluorinated hydrocarbon polymer.
15 . The device of claim 1 , wherein the anode comprises a source of ions of a metal selected from Groups 1, 2, and 3 of the Periodic Table of the Elements.
16 . The device of claim 15 , wherein the ions are lithium ions.
17 . The device of claim 16 , wherein the source of lithium ions is selected from lithium metal, a lithium alloy, and a carbon-lithium material.
18 . The device of claim 17 , wherein the source of lithium ions is lithium metal.
19 . The device of claim 1 , wherein the ion-transporting material physically separates the anode and the cathode and prevents direct electrical contact therebetween.
20 . The device of claim 19 , wherein the ion-transporting material comprises a polymeric material and a nonaqueous electrolyte.
21 . The device of claim 1 , wherein the device is a primary lithium battery and:
the anode comprises a source of lithium ions;
the cathode comprises a subfluorinated graphite fluoride of formula CF x in which x is in the range of 0.06 to 0.52, wherein the subfluorinated graphite fluoride comprises a particulate material having an average particle size in the range of about 4 microns to about 7.5 microns; and
the ion-transporting material physically separates the anode and the cathode and prevents direct electrical contact therebetween, wherein the material comprises a nonaqueous electrolyte.
22 . The device of claim 21 , wherein x is in the range of 0.10 to 0.52.
23 . The device of claim 22 , wherein x is in the range of 0.10 to 0.46.
24 . The device of claim 23 , wherein x is in the range of 0.33 to 0.46.
25 . An electrode for use in an electrochemical device that converts chemical energy to electrical current, the electrode comprising a subfluorinated graphite fluoride of formula CF x in which x is in the range of 0.10 to 0.52, wherein the subfluorinated graphite fluoride comprises a particulate material having an average particle size in the range of about 4 microns to about 7.5 microns.
26 . The electrode of claim 25 , wherein x is in the range of 0.10 to 0.52.
27 . The electrode of claim 26 , wherein x is in the range of 0.10 to 0.46.
28 . The electrode of claim 25 , wherein x is in the range of 0.33 to 0.46.
29 . The electrode of claim 25 , wherein the subfluorinated composition further comprising a conductive diluent and a binder.
30 . The electrode of claim 29 , wherein the conductive diluent is selected from acetylene black, carbon black, powdered graphite, cokes, carbon fibers, metallic powders, and combinations thereof.
31 . The electrode of claim 30 , wherein the conductive diluent is acetylene black.
32 . The electrode of claim 29 , wherein the binder is polymeric.
33 . The electrode of claim 32 , wherein the binder is a fluorinated hydrocarbon polymer.
34 . A method for preparing an electrode for use in an electrochemical device, comprising:
contacting graphite powder having an average particle size in the range of 1 micron to about 10 microns with a gaseous source of elemental fluorine at a temperature in the range of about 375° C. to about 400° C. for a time period of about 5 to about 80 hours, whereby a subfluorinated graphite fluoride is provided having the formula CF x in which x is in the range of 0.06 to 0.63;
admixing the subfluorinated graphite fluoride with a conductive diluent and a binder to form a slurry; and
applying the slurry to a conductive substrate.
35 . The method of claim 34 , wherein the graphite powder has an average particle size in the range of 4 microns to about 7.5 microns.
36 . The method of claim 34 , wherein the time period is in the range of about 15 to about 35 hours.
37 . A rechargeable battery comprising:
a first electrode comprising a subfluorinated graphite fluoride of formula CF x in which x is in the range of 0.06 to 0.63, and capable of receiving and releasing cations of a metal selected from Groups 1, 2, and 3 of the Periodic Table of the Elements;
a second electrode comprising a source of said metal cations; and
a solid polymer electrolyte that permits transport of said metal cations and physically separates the first and second electrodes.
38 . The rechargeable battery of claim 37 , wherein the metal is lithium.