Negative active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery comprising the same

• US 20050233213A1
• Filed: 03/08/2005
• Published: 10/20/2005
• Est. Priority Date: 03/08/2004
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Lee, Sang-Min, Kim, Sung-Soo, Jeong, Goo-Jin, Nitta, Yoshiaki
• Granted Patent: US 8,709,653 B2
• Time in Patent Office: Days
• US Class Current: 429/218.100
• CPC Class Codes: C01B 35/12 Borates C01B35/1063 takes precedence
• 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 4/0402 Methods of deposition of the material
• CPC Class Codes: H01M 4/13 Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: H01M 4/139 Processes of manufacture
• CPC Class Codes: H01M 4/362 Composites
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• 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: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The present invention relates to a negative active material for a rechargeable lithium battery, which includes a silicon-based composite having a silicon oxide of the form SiO_X where x≦1.5 and at least one element selected from the group consisting of B, P, Li, Ge, Al, and V, and a carbonaceous material. The negative active material of the present invention can improve the cycle-life and high-rate charge/discharge characteristics of a rechargeable lithium battery.

Claims

1. A negative active material for a rechargeable lithium battery, comprising:

a silicon-based composite comprising;

a silicon oxide of the form SiO_X where, x≦

1.5, and one or more elements selected from the group consisting of B, P, Li, Ge, Al, and V; and

a carbonaceous material.

2. The negative active material according to claim 1, where x is between 0.5 and 1.5.

3. The negative active material according to claim 1, wherein the one or more elements selected from the group consisting of B, P, Li, Ge, Al, and V are provided in an amount not more than 50 wt % with respect to the total weight of the silicon-based composite.

4. The negative active material according to claim 3, wherein the one or more elements selected from the group consisting of B, P, Li, Ge, Al, and V are provided in an amount from 10 wt % to 30 wt % with respect to the total weight of the silicon-based composite.

5. The negative active material according to claim 1, wherein the silicon oxide is doped with the one or more elements selected from the group consisting of B, P, Li, Ge, Al, and V.

6. The negative active material according to claim 1, wherein the carbonaceous material is crystalline carbon or amorphous carbon.

7. The negative active material according to claim 1, wherein the silicon-based composite further comprises Si, SiO₂, or mixtures thereof.

8. The negative active material according to claim 1, wherein the silicon-based composite and the carbonaceous material are provided in a weight ratio between 10:

90 and 90;

10.

9. The negative active material according to claim 1, wherein the silicon-based composite and the carbonaceous material are provided in a weight ratio between 30:

70 and 70;

30.

10. The negative active material according to claim 1, wherein the negative active material has an amorphorization degree of over 50% and the amorphorization degree is calculated based on an X-ray diffraction peak by the following Calculation Formula:

Amorphorization degree (%)=((Main XRD peak intensity of the silicon-based composite after carrying out a quenching treatment)/(Main XRD peak intensity of the silicon-based composite before carrying out the quenching treatment))×

100.

11. The negative active material according to claim 1, wherein the negative active material has a Li diffusion rate of over 10⁻

8 cm²/sec based on a Galvanic Intermittent Time Technique (GITT) method.

12. The negative active material according to claim 1, wherein the negative active material comprises the silicon-based composite with the carbonaceous material coated on the surface of the silicon-based composite.

13. The negative active material according to claim 1, wherein the negative active material comprises a mixture of the silicon-based composite and the carbonaceous material.

14. The negative active material according to claim 1, wherein the carbonaceous material is a first carbonaceous material, and the negative active material comprises the mixture of the silicon-based composite and the first carbonaceous material coated with a second carbonaceous material.

15. A method for preparing a negative active material for a rechargeable lithium battery, comprising:

mixing a compound selected from the group consisting of B-containing compounds, P-containing compounds, Li-containing compounds, Ge-containing compounds, Al-containing compounds, V-containing compounds, and combinations thereof, with SiO₂ and Si to thereby produce a mixture;

heat treating the mixture to prepare a silicon-based composite comprising a silicon oxide of the form SiO_X where x≦

1.5, and one or more elements selected from the group consisting of B, P, Li, Ge, Al, and V;

quenching the silicon-based composite; and

coating the silicon-based composite with a carbonaceous material.

16. The method for preparing a negative active material for a rechargeable lithium battery according to claim 15, wherein the SiO₂ and Si are mixed in a weight ratio between 3:

1 and 1;

1.

17. The method for preparing a negative active material for a rechargeable lithium battery according to claim 15, wherein the one or more compounds selected from the group consisting of B-containing compounds, P-containing compounds, Li-containing compounds, Ge-containing compounds, Al-containing compounds, and V-containing compounds is a glass network former.

18. The method for preparing a negative active material for a rechargeable lithium battery according to claim 15, wherein the one or more compounds are selected from the group consisting of B₂O₃, B₂O, P₂O₅, P₂O₃, Li₂O, Li₂CO₃, LiOH, GeO₂, Al₂O₃, and V₂O₅.

19. The method for preparing a negative active material for a rechargeable lithium battery according to claim 15, wherein the one or more compounds are added in an amount less than or equal to 50 weight wt % based on the total weight of SiO₂ and Si.

20. The method for preparing a negative active material for a rechargeable lithium battery according to claim 19, wherein the one or more compounds are added in an amount between 10 and 30 wt % based on the total weight of SiO₂ and Si.

21. The method for preparing a negative active material for a rechargeable lithium battery according to claim 15, wherein the heat treating is performed at a temperature between 600°

C. and 1000°

C.

22. The method for preparing a negative active material for a rechargeable lithium battery according to claim 21, wherein the heat treating is performed at a temperature between 800°

C. and 1000°

C.

23. The method for preparing a negative active material for a rechargeable lithium battery according to claim 15, wherein x is between 0.5 and 1.5.

24. The method for preparing a negative active material for a rechargeable lithium battery according to claim 15, wherein the carbonaceous material is crystalline carbon or amorphous carbon.

25. A method for preparing a negative active material for a rechargeable lithium battery, comprising:

mixing SiO₂ and Si with one or more compounds selected from the group consisting of B-containing compounds, P-containing compounds, Li-containing compounds, Ge-containing compounds, Al-containing compounds, and V-containing compounds to thereby produce a mixture;

heat treating the mixture to prepare a silicon-based composite comprising;

a silicon oxide of the form SiO_X where x≦

1.5, and one or more elements selected from the group consisting of B, P, Li, Ge, Al, and V; and

mixing the silicon-based composite with a carbonaceous material.

26. The method for preparing a negative active material for a rechargeable lithium battery according to claim 25, wherein the one or more compounds is selected from the group consisting of B₂O₃, B₂O, P₂O₅, P₂O₃, Li₂O, Li₂CO₃, LiOH, GeO₂, Al₂O₃, and V₂O₅.

27. The method for preparing a negative active material for a rechargeable lithium battery according to claim 25, wherein the SiO₂ and Si are mixed in a weight ratio between 3:

1 and 1;

1.

28. The method for preparing a negative active material for a rechargeable lithium battery according to claim 25, wherein the one or more compounds are a glass network former.

29. The method for preparing a negative active material for a rechargeable lithium battery according to claim 25, wherein the heat treating is performed at a temperature between 600°

C. and 1000°

C.

30. The method for preparing a negative active material for a rechargeable lithium battery according to claim 29, wherein the heat treating is performed at a temperature between 800°

C. and 1000°

C.

31. The method for preparing a negative active material for a rechargeable lithium battery according to claim 25, further comprising quenching after performing the heat treatment.

32. The method for preparing a negative active material for a rechargeable lithium battery according to claim 25, wherein x is between 0.5 and 1.5.

33. The method for preparing a negative active material for a rechargeable lithium battery according to claim 25, wherein the one or more compounds are added in an amount of less than or equal to 50 wt % based on the total weight of SiO₂ and Si.

34. The method for preparing a negative active material for a rechargeable lithium battery according to claim 33, wherein the one or more compounds are added in an amount between 10 and 30 wt % based on the total weight of SiO₂ and Si.

35. The method for preparing a negative active material for a rechargeable lithium battery according to claim 25, wherein the carbonaceous material is crystalline carbon or amorphous carbon.

36. The method for preparing a negative active material for a rechargeable lithium battery according to claim 25, wherein the silicon-based composite and the carbonaceous material are provided in weight ratio between 10:

90 and 90;

10.

37. The method for preparing a negative active material for a rechargeable lithium battery according to claim 36, wherein the weight ratio of the silicon-based composite to the carbonaceous material is between 30:

70 and 70;

30.

38. The method for preparing a negative active material for a rechargeable lithium battery according to claim 25, wherein the carbonaceous material is a first carbonaceous material, the method further comprising coating the mixture of the silicon-based composite and the first carbonaceous material with a second carbonaceous material.

39. A rechargeable lithium battery, comprising:

a negative electrode including a negative active material comprising a carbonaceous material and a silicon-based composite comprising;

a silicon oxide of the form SiO_X where x≦

1.5 and one or more elements selected from the group consisting of B, P, Li, Ge, Al, and V;

a positive electrode including a positive active material capable of reversibly intercalating/deintercalating lithium; and

an electrolyte.