Coated vertically aligned carbon nanotubes on nickel foam
View Patent ↗Vertically aligned carbon nanotubes (VACNTs) (e.g., multi-walled VACNTs and methods of synthesizing the same are provided. VACNTs can be synthesized on nickel foam (Ni—F), for example by using a plasma-enhanced chemical vapor deposition (PECVD) technique. A wet chemical method can then be used to coat on the VACNTs a layer of nanoparticles, such as tin oxide (SnO 2 ) nanoparticles.
1. A method of synthesizing vertically aligned carbon nanotubes (VACNTs), the method comprising:
providing a pristine nickel foam (Ni—F) substrate in a reaction chamber;
lowering a pressure of the reaction chamber and providing a carbon precursor gas to the chamber to perform a plasma-enhanced chemical vapor deposition (PECVD) process to synthesize the VACNTs directly on the pristine Ni—F substrate; and
performing a wet chemical process on the VACNTs connected directly to the Ni—F substrate to coat the VACNTs with nanoparticles such that the VACNTs have a coating of the nanoparticles on respective outer walls thereof.
2. The method according to claim 1 , the VACNTs being multi-walled VACNTs.
3. The method according to claim 1 , further comprising, after performing the PECVD process, performing an acid treatment on the VACNTs connected to the Ni—F substrate to form oxygen-containing functional groups on the respective outer walls of the VACNTs.
4. The method according to claim 3 , the acid treatment comprising providing a first acid to the VACNTs for a first predetermined amount of time.
5. The method according to claim 4 , the first acid being nitric acid (HNO 3 ) and the first predetermined amount of time being at least 10 minutes.
6. The method according to claim 3 , the oxygen-containing functional groups comprising carboxyl groups and hydroxyl groups.
7. The method according to claim 1 , the nanoparticles being tin oxide (SnO 2 ) nanoparticles.
8. The method according to claim 7 , the wet chemical process comprising providing tin (II) chloride dihydrate (SnCl 2 .2H 2 O) and oxygen (O 2 ) to the VACNTs.
9. The method according to claim 7 , the wet chemical process comprising:
forming a precursor solution comprising a second acid and SnCl 2 .2H 2 O; and
submerging the VACNTs on the Ni—F substrate in the precursor solution while providing O 2 for a second predetermined amount of time such that the SnO 2 nanoparticles coat the respective outer walls of the VACNTs.
10. The method according to claim 9 , the second acid being hydrochloric acid (HCl) and the second predetermined amount of time being at least 1 hour.
11. The method according to claim 1 , the VACNTs being binder-free.
12. A compound comprising:
a nickel foam (Ni—F) substrate;
vertically aligned carbon nanotubes (VACNTs) disposed on and directly connected to the Ni—F substrate; and
a coating of the nanoparticles on respective outer walls of the VACNTs.
13. The compound according to claim 12 , the nanoparticles being tin oxide (SnO 2 ) nanoparticles.
14. The compound according to claim 12 , the VACNTs being multi-walled VACNTs.
15. The compound according to claim 12 , the VACNTs being binder-free.
16. The compound according to claim 12 , the VACNTs comprising oxygen-containing functional groups on the respective outer walls thereof.
17. A lithium-ion battery, comprising:
a cathode comprising lithium;
an anode comprising the compound according to claim 12 ; and
an electrolyte disposed between the cathode and the anode,
the nanoparticles being tin oxide (SnO 2 ) nanoparticles.
18. The lithium-ion battery according to claim 17 , the VACNTs being multi-walled VACNTs,
the VACNTs being binder-free,
the VACNTs comprising oxygen-containing functional groups on the respective outer walls thereof, and
the oxygen-containing functional groups comprising carboxyl groups and hydroxyl groups.
19. A method of synthesizing vertically aligned carbon nanotubes (VACNTs), the method comprising:
providing a pristine nickel foam (Ni—F) substrate in a reaction chamber;
lowering a pressure of the reaction chamber and providing a carbon precursor gas to the chamber to perform a plasma enhanced chemical vapor deposition (PECVD) process to synthesize the VACNTs d on the directly on the pristine Ni—F substrate;
after performing the PECVD process, performing an acid treatment on the VACNTs di connected to the Ni—F substrate to form oxygen-containing functional groups on respective outer walls of the VACNTs; and
performing a wet chemical process on the VACNTs directly connected to the Ni—F substrate to coat the VACNTs with nanoparticles such that the VACNTs have a coating of the nanoparticles on the respective outer walls thereof,
the VACNTs being multi-walled VACNTs,
the acid treatment comprising providing a first acid to the VACNTs for a first predetermined amount of time,
the oxygen-containing functional groups comprising carboxyl groups and hydroxyl groups,
the nanoparticles being tin oxide (SnO 2 ) nanoparticles,
the wet chemical process comprising: forming a precursor solution comprising a second acid and tin (II) chloride dihydrate (SnCl 2 .2H 2 O); and submerging the VACNTs directly on the Ni—F substrate in the precursor solution while providing oxygen (O 2 ) for a second predetermined amount of time such that the SnO 2 nanoparticles coat the respective outer walls of the VACNTs, and
the VACNTs being binder-free.
20. The method according to claim 19 , the first acid being nitric acid (HNO 3 ),
the first predetermined amount of time being at least 10 minutes,
the second acid being hydrochloric acid (HCl), and
the second predetermined amount of time being at least 1 hour.