Self standing electrodes and methods for making thereof
The present disclosure relates to a method of making a composite product that may be used as a flexible electrode. An aerosolized mixture of nanotubes and an electrode active material is collected on a porous substrate, such as a filter, until it reaches a desired thickness. The resulting self-standing electrode may then be removed from the porous substrate and may operate as a battery electrode.
1. A method of producing a self-standing electrode, the method comprising:
aerosolizing an electrode active material to produce an aerosolized electrode active material powder;
contacting the aerosolized electrode active material powder with single-walled carbon nanotubes in a carrier gas to form a mixture of the single-walled carbon nanotubes and the aerosolized electrode active material powder;
collecting the mixture on a porous surface, wherein at least a portion of the carrier gas passes through the porous surface; and
removing the mixture from the porous surface, to form the self-standing electrode material that is a composite of the single-walled carbon nanotubes and the electrode active material, wherein the self-standing electrode is free of binder and metal-based current collector, and wherein the self-standing electrode comprises 0.1% to 4% by weight carbon nanotubes and has a density of 0.75 g/cc to 2.28 g/cc.
2. The method of claim 1 , wherein the aerosolizing of the electrode active material comprises distributing an aerosolizing gas through a first porous frit and a bed of an electrode active material, in an aerosolizing reactor, to produce the aerosolized electrode active material powder.
3. The method of claim 1 , further comprising providing the single-walled carbon nanotubes from a carbon nanotube synthesis reactor.
4. The method of claim 1 , wherein the porous surface is comprised by a porous frit in a collection chamber.
5. The method of claim 1 , wherein the electrode active material is selected from graphite, hard carbon, lithium metal oxides, and lithium iron phosphate.
6. The method of claim 1 , further comprising synthesizing the single-walled carbon nanotubes in a carbon nanotube synthesis reactor.
7. The method of claim 6 , wherein the contacting of the aerosolized electrode active material powder with the single-walled carbon nanotubes occurs downstream of the carbon nanotube synthesis reactor and upstream of the porous surface.
8. A method of producing a self-standing electrode, the method comprising:
providing an aerosolized mixture of carbon nanotubes and an electrode active material powder;
providing at least a first porous substrate;
directing the aerosolized mixture toward the first porous substrate;
collecting the mixture on the first porous substrate; and
removing the mixture from the first porous substrate to form the self-standing electrode, wherein the self-standing electrode is free of binder and metal-based current collector, and wherein the self-standing electrode comprises 0.1% to 4% by weight carbon nanotubes and has a density of 0.75 g/cc to 2.28 g/cc.
9. The method of claim 8 wherein the aerosolized mixture comprises at least one carrier gas that passes through the porous substrate as the mixture is collected on the porous substrate.
10. The method of claim 9 wherein the mixture is collected on the porous substrate until the collected mixture comprises a thickness of up to 750 μm.
11. The method of claim 10 wherein the mixture is collected on the porous substrate until the collected mixture comprises a thickness of 100 μm to 450 μm.
12. The method of claim 10 wherein the self-standing electrode has a density of 0.75 g/cc to 2.0 g/cc.
13. The method of claim 12 wherein the self-standing electrode has a density of 0.95 g/cc to 1.60 g/cc.
14. The method of claim 8 further comprising treating the self-standing electrode to increase the density of the self-standing electrode, wherein the treated self-standing electrode has a density that is 40% to 125% greater than the density of the untreated self-standing electrode.
15. The method of claim 14 wherein the treated self-standing electrode has a density that is 45% to 90% greater than the density of the untreated self-standing electrode.
16. The method of claim 14 wherein the treated self-standing electrode has a thickness that is 40% to 75% of the thickness of the untreated self-standing electrode.
17. The method of claim 8 wherein the step of providing an aerosolized mixture of carbon nanotubes and an electrode active material powder comprises:
providing a first aerosolized stream comprising the carbon nanotubes and at least one carrier gas;
providing a second aerosolized stream comprising the electrode active material powder and at least one carrier gas; and
mixing the first aerosolized stream and the second aerosolized stream to provide the aerosolized mixture.
18. The method of claim 17 wherein the first aerosolized stream comprises a product stream exiting from a nanotube synthesis reactor.
19. The method of claim 18 further comprising:
providing a carbon source in the nanotube synthesis reactor;
growing carbon nanotubes in the presence of a carrier gas;
transferring the product stream comprising the carbon nanotubes and the carrier gas out of the nanotube synthesis reactor as the first aerosolized stream.
20. The method of claim 8 further comprising:
redirecting the mixture toward a second porous substrate after the collected mixture formed on the first porous substrate comprises a first desired thickness; and
collecting the mixture on the second porous substrate until a second collected mixture comprises a second desired thickness.
21. The method of claim 20 wherein the step of redirecting the mixture further comprises:
measuring a pressure drop across a first porous surface of the first porous substrate; and
redirecting the mixture toward the second porous substrate after a pressure drop associated with the first desired thickness is measured across the first porous surface.
22. The method of claim 8 wherein the self-standing electrode comprises 0.2% to 3% by weight carbon nanotubes.
23. The method of claim 22 wherein the self-standing electrode comprises 0.75% to 2% by weight carbon nanotubes.
24. The method of claim 8 wherein the self-standing electrode consists essentially of the carbon nanotubes and the electrode active material powder.
25. The method of claim 8 wherein the self-standing electrode consists of the carbon nanotubes and the electrode active material powder.
26. The method of claim 8 wherein the nanotubes comprises single-walled carbon nanotubes.
27. The method of claim 26 wherein the electrode active material powder comprises graphite.
28. The method of claim 26 wherein the electrode active material powder comprises a metal oxide.
29. The method of claim 28 wherein the electrode active material powder comprises LiNiMnCoO 2 .
30. The method of claim 26 wherein the self-standing electrode comprises a webbed arrangement of the carbon nanotubes with the electrode active material embedded within the carbon nanotube web.
31. The method of claim 30 wherein the self-standing electrode is flexible.