Lithium-ion battery incorporating carbon nanostructure materials

• US 20060051674A1
• Filed: 09/03/2004
• Published: 03/09/2006
• Est. Priority Date: 09/03/2004
• Status: Active Grant

• Current Assignee: Hong Kong University of Science and Technology
• Original Assignee: Hong Kong University of Science and Technology
• Inventors: Wang, Ning, Sheng, Ping, Liang, Qi, Tang, Zikang, Chan, Che Ting
• Granted Patent: US 7,465,519 B2
• Time in Patent Office: Days
• US Class Current: 429/231.800
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10S 977/75 Single-walled

Abstract

A lithium ion battery is disclosed in which the negative electrode material comprises carbon nanostructures having no dimension greater than 2 μm. The battery has a high reversible capacity of the order of 400 mAh/g to 500 mAh/g which can be maintained over a long cycle-life (at least 30 cycles). The carbon nanostructures may be mixed with graphite to improve conductivity. The carbon nanostructues may be synthesized using an AFI template material followed by calcination.

Claims

1. A lithium ion battery wherein the negative electrode material comprises carbon nanostructures having no dimension greater than 2 μ

m.

2. A battery as claimed in claim 1 wherein the negative electrode material comprises a mixture of said carbon nanostructures and graphite.

3. A battery as claimed in claim 2 wherein said carbon nanostructures comprise from 10 wt % to 90 wt % of said mixture.

4. A battery as claimed in claim 3 wherein said carbon nanostructures comprise 50 wt % of said mixture.

5. A battery as claimed in claim 1 wherein said negative electrode material comprises said carbon nanostructures and a binder.

6. A battery as claimed in claim 1 wherein the carbon nanostructures comprises a mixture of approximately 90% amorphous nanocarbon and 10% single-walled carbon nanotubes.

7. A battery as claimed in claim 1 wherein said carbon nanostructures are synthesized by means of a method comprising the steps of comprising the steps of:

(a) synthesising a microporous template material comprising crystals having no dimension greater than about 2 μ

m, (b) heating said crystals in the presence of an inert gas or a mixture of an inert gas and a carbon-containing gas at a temperature of between 500°

C. and 900°

C., and (c) recovering said carbon nanostructures by washing the heated crystals in an acid to remove the template material.

8. A lithium ion battery wherein the negative electrode material comprises carbon nanostructures that are synthesized by means of a method comprising the steps of:

(a) synthesising a microporous template material comprising crystals having no dimension greater than about 2 μ

m, (b) heating said crystals in the presence of an inert gas or a mixture of an inert gas and a carbon-containing gas at a temperature of between 500°

C. and 900°

C., and (c) recovering said carbon nanostructures by washing the heated crystals in an acid to remove the template material.

9. A lithium ion battery comprising carbon nanostructures as a negative electrode material and having a reversible capacity in the range of 400 to 500 mAh/g.

10. A battery as claimed in claim 9 wherein the reversible capacity remains substantially unaltered over at least 30 charging cycles.