METHOD OF PREPARING NEGATIVE ACTIVE MATERIAL FOR A RECHARGEABLE LITHIUM BATTERY AND A RECHARGEABLE LITHIUM BATTERY

• US 20110256452A1
• Filed: 01/14/2011
• Published: 10/20/2011
• Est. Priority Date: 04/19/2010
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation), Ulsan National Institute of Science and Technology
• Original Assignee: LG Chem Limited (LG Corporation), UNIST Academy-Industry Research CorporationUNIST
• Inventors: Park, Mi-Hee, Cho, Jaephil, Kim, Hye-Jung, Seo, Min-Ho, Kim, Ki-Tae, Kim, Je-Young
• Granted Patent: US 9,306,209 B2
• Time in Patent Office: Days
• US Class Current: 429/218.1
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/366 as layered products
• CPC Class Codes: H01M 4/38 of elements or alloys
• CPC Class Codes: H01M 4/625 Carbon or graphite
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention provides a method of preparing a negative active material for a rechargeable lithium battery, comprising the steps of: mixing a silicon precursor, a surfactant comprising an ammonium halide salt having a organic group, an initiator, and a solvent; heat-treating the mixture; cooling the heat-treated mixture to room temperature; washing the cooled, heat treated mixture; and calcining the washed product.

Claims

1. A method of preparing a negative active material for a rechargeable lithium battery comprising the steps of:

a) mixing a silicon precursor, a surfactant comprising an ammonium halide salt having a organic group, an initiator, and a solvent;

b) heat-treating the mixture;

c) cooling the heat-treated mixture to room temperature;

d) washing the cooled, heat-treated mixture; and

e) calcining the washed product.

2. The method according to claim 1, wherein the ammonium halide salt is represented by the following Chemical Formula 1:

3. The method according to claim 1, wherein the heat-treated mixture is a reverse micelle structure.

4. The method according to claim 1, wherein the mixture comprises 50 to 70 weight % of the silicon precursor, 5 to 20 weight % of the surfactant, 10 to 45 weight % of the initiator, and the remaining weight % of the solvent.

5. The method according to claim 1, wherein the silicon precursor is silicon halide.

6. The method according to claim 1, wherein the initiator is sodium naphthalide.

7. The method according to claim 1, wherein the solvent is hexane, isopropyl alcohol, or a mixture thereof.

8. The method according to claim 1, wherein the heat-treatment is carried out at the temperature of 300°

C. to 500°

C.

9. The method according to claim 1, wherein the washing process is carried out by using hexane, water, or a mixture thereof.

10. The method according to claim 1, wherein the calcination step is carried out at a temperature of 600°

C. to 1000°

C.

11. The method according to claim 1, further comprising the step of coating the surface of the calcined product with carbon.

12. The method according to claim 1, wherein the negative active material for the rechargeable lithium battery comprises a core comprising silicon, and a coating layer comprising carbon on the surface of the core.

13. The method according to claim 12, wherein the negative active material for the rechargeable lithium battery has a particle diameter of 3 nm to 30 nm, and the particle diameter has a deviation of 2 nm or less.

14. The method according to claim 12, wherein the silicon in the core is crystalline and the carbon in the coating layer is amorphous.

15. The method according to claim 12, wherein the coating layer has a thickness of 0.5 nm to 5 nm.

16. The method according to claim 12, wherein the negative active material for the rechargeable lithium battery has a dispersity of 70 to 95%.

17. A rechargeable lithium battery comprising:

a negative electrode comprising a negative active material for a rechargeable lithium battery prepared by the method of claim 1;

a positive electrode comprising a positive active material; and

an electrolyte.