Electrolyte for rechargeable lithium battery and rechargeable lithium battery comprising same

• US 20050142448A1
• Filed: 11/01/2004
• Published: 06/30/2005
• Est. Priority Date: 10/31/2003
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Kim, Jin-Sung, Kim, Jin-Hee
• Granted Patent: US 7,745,055 B2
• Time in Patent Office: Days
• US Class Current: 429/326
• CPC Class Codes: H01M 10/052 Li-accumulators
• 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 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• CPC Class Codes: H01M 2300/0025 Organic electrolyte
• CPC Class Codes: H01M 2300/0034 Fluorinated solvents
• CPC Class Codes: H01M 2300/0037 Mixture of solvents
• 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 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 6/164 by the solvent
• CPC Class Codes: H01M 6/168 by additives
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Disclosed is an electrolyte for a rechargeable lithium battery including: a first additive having an oxidation potential of 4.1 to 4.6V; a second additive having an oxidation potential of 4.4 to 5.0V; a non-aqueous organic solvent; and a lithium salt.

Claims

1. An electrolyte for a rechargeable lithium battery, comprising:

a first additive having an oxidation potential from 4.1 to 4.6V;

a second additive having an oxidation potential from 4.4 to 5.0V;

a non-aqueous organic solvent; and

a lithium salt.

2. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the first additive has an oxidation potential from 4.1 to 4.4V.

3. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the first additive has an oxidation potential from 4.2 to 4.4V.

4. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the second additive has an oxidation potential from 4.6 to 5.0V.

5. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the second additive has an oxidation potential from 4.7 to 4.9V.

6. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the oxidation potential of the first additive is from 0.1 to 0.7V less than the oxidation potential of the second additive.

7. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the oxidation potential of the first additive is from 0.3 to 0.7V less than the oxidation potential of the second additive.

8. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the electrolyte has an oxidation potential from 4.4 to 4.9V.

9. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the electrolyte has an oxidation potential from 4.5 to 4.7V.

10. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the first additive comprises at least one compound selected from the compounds represented by Formulae 1 and 2:

11. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the first additive comprises at least one compound selected from the compounds represented by Formulae 2 to 4:

12. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the first additive comprises a compound of Formula 2:

13. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the second additive comprises at least one compound selected from the group consisting of compounds represented by Formulae 5 to 9:

14. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the second additive comprises at least one compound selected from the group consisting of compounds represented by Formulae 5, and 10 to 13:

15. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the second additive is represented by Formula 5:

16. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the combined amount of the first additive and the second additive is 0.01 to 20% by weight based on the total weight of the non-aqueous organic solvent and the lithium salt.

17. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the combined amount of the first additive and the second additive is 0.1 to 10% by weight based on the total weight of the non-aqueous organic solvent and the lithium salt.

18. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the combined amount of the first additive and the second additive is 5 to 10% by weight based on the total weight of the non-aqueous organic solvent and the lithium salt.

19. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the second additive and the first additive are mixed at a weight ratio of 20:

0.1 to 3;

2.

20. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the electrolyte comprises 0.1 to 5% by weight of the first additive and 1 to 20% by weight of the second additive.

21. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the non-aqueous organic solvent is selected from the group consisting of carbonates, esters, ethers, ketones and combinations thereof.

22. The electrolyte for a rechargeable lithium battery according to claim 21, wherein the non-aqueous organic solvent is a carbonate selected from the group consisting of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, methylethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate and combinations thereof.

23. The electrolyte for a rechargeable lithium battery according to claim 21, wherein the non-aqueous organic solvent comprises a mixed solvent of cyclic carbonates and chain carbonates.

24. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the non-aqueous organic solvent is a mixed solvent of a carbonate solvent and an aromatic hydrocarbon organic solvent.

25. The electrolyte for a rechargeable lithium battery according to claim 24, wherein the aromatic hydrocarbon organic solvent is a compound represented by Formula 14:

26. The electrolyte for a rechargeable lithium battery according to claim 24, wherein the aromatic hydrocarbon organic solvent is selected from the group consisting of benzene, fluorobenzene, chlorobenzene, nitrobenzene, toluene, fluorotoluene, trifluorotoluene, xylene and mixtures thereof.

27. The electrolyte for a rechargeable lithium battery according to claim 24, wherein the carbonate solvent and an aromatic hydrocarbon organic solvent are mixed in a volume ratio between 1:

1 and 30;

1.

28. The electrolyte for a rechargeable lithium battery according to claim 1, wherein the lithium salt is selected from the group consisting of LiPF₆, LiBF₄, LiSbF₆, LiAsF₆, LiClO₄, CF₃SO₃Li, LiN(SO₂CF₃)₂, LiC₄F₉SO₃, LiAlO₄, LiAlOCl₄, LiN(SO₂C₂F₅)₂), LiN(C_xF_2x+1SO₂)(C_yF_2y+1SO₂) where x and y are natural numbers, LiCl, Lil and combinations thereof.

29. An electrolyte for a rechargeable lithium battery, comprising:

a first additive comprising a compound represented by Formula 2;

a second additive comprising a compound represented by Formula 5;

a non-aqueous organic solvent, and

a lithium salt,

wherein, R1 and R5 are independently selected from the group consisting of C₁-C₆ alkyl groups and C₂-C₆ alkylene groups; and

X is selected from the group consisting of Cl, Br, and F.

30. The electrolyte for a rechargeable lithium battery according to claim 29, wherein the electrolyte comprises 0.1 to 5% by weight of the first additive and 1 to 20% by weight of the second additive.

31. An electrolyte for a rechargeable lithium battery, comprising:

a first additive having an oxidation potential of 4.1 to 4.5V;

a second additive having an oxidation potential of 4.5 to 5.0V;

a non-aqueous organic solvent; and

a lithium salt;

wherein the electrolyte has an oxidation potential from 4.4 to 4.9V.

32. The electrolyte for a rechargeable lithium battery according to claim 31, wherein the electrolyte has an oxidation potential from 4.5 to 4.7V.

33. A rechargeable lithium battery, comprising:

an electrolyte comprising a first additive having an oxidation potential from 4.1 to 4.6V, a second additive having an oxidation potential from 4.5 to 5.0V, a non-aqueous organic solvent, and a lithium salt;

a positive electrode comprising a positive active material capable of reversibly intercalating and deintercalating lithium ions; and

a negative electrode capable of reversibly intercalating and deintercalating lithium ions.

34. The rechargeable lithium battery according to claim 33, wherein the first additive has an oxidation potential from 4.1 to 4.4V.

35. The electrolyte for a rechargeable lithium battery according to claim 34, wherein the first additive has an oxidation potential from 4.2V to 4.4V.

36. The rechargeable lithium battery according to claim 33, wherein the second additive has an oxidation potential from 4.6 to 5.0V.

37. The rechargeable lithium battery according to claim 36, wherein the second additive has an oxidation potential from 4.7 to 4.9V.

38. The rechargeable lithium battery according to claim 33, wherein the oxidation potential of the first additive is from 0.1 to 0.7V less than the oxidation potential of the second additive.

39. The rechargeable lithium battery according to claim 33, wherein the oxidation potential of the first additive is from 0.3 to 0.7V less than the oxidation potential of the second additive.

40. The rechargeable lithium battery according to claim 33, wherein the first additive comprises at least one compound selected from the compounds represented by Formulae 1 and 2:

41. The rechargeable lithium battery according to claim 33, wherein the first additive comprises a compound selected from the compounds represented by Formulae 2 to 4:

42. The rechargeable lithium battery according to claim 40, wherein the first additive comprises a compound represented by Formula 2.

43. The rechargeable lithium battery according to claim 33, wherein the second additive comprises a compound selected from the group consisting of compounds represented by Formulae 5 to 9:

44. The rechargeable lithium battery according to claim 33, wherein the second additive comprises a compound selected from the group consisting of compounds represented by Formulae 5 and 10 to 13:

45. The rechargeable lithium battery according to claim 43, wherein the second additive is represented by Formula 5 where X is selected from the group consisting of Cl, Br, and F, and R1 is selected from the group consisting of C₁-C₆ alkyl groups and C₂-C₆ alkylene groups.

46. The rechargeable lithium battery according to claim 43, wherein the positive active material comprises lithiated intercalation oxides.

47. The rechargeable lithium battery according to claim 33, wherein the negative active material is selected from the group consisting of crystalline carbon, amorphous carbon, carbon complex, and lithium metals.

48. The rechargeable lithium battery according to claim 46, wherein the negative active material is crystalline carbon.

49. The rechargeable lithium battery according to claim 33, wherein, the negative active material is crystalline carbon having an Lc of 150 Å

or more, a d(002) between 3.35 and 3.38 Å

, a true density of 2.2 g/cm³ or more, a BET (specific surface area) between 0.5 and 50 m²/g, and an average particle diameter (D50) between 1 and 30 μ

m.

50. The rechargeable lithium battery according to claim 48, wherein the negative active material has an intensity ratio Ra I(I(1360 cm⁻

1)/I(1580 cm<sup>−

1</sup>)) of a Raman Spectroscopy peak intensity I(1360) at a (1360) plane to an Raman Spectroscopy peak intensity I(1590) at a (1590) plane of 0.05 or more.

51. The rechargeable lithium battery according to claim 48, wherein the negative active material has an X-ray diffraction peak intensity ratio I(I(110)/I(002)) of an X-ray diffraction peak intensity (110) at a (110) plane to an X-ray diffraction peak intensity I(002) at a (002) plane of 0.2 or less.

52. The rechargeable lithium battery according to claim 33, wherein at least one of the positive electrode and the negative electrode comprises a water soluble binder and a water soluble agent for increasing viscosity.

53. The rechargeable lithium battery according to claim 51, wherein the water soluble binder is selected from the group consisting of styrene-butadiene rubber, polysodium acrylate, copolymers of propylene and C₂-C₈ olefin, and copolymers of (meth)acrylic acid and (meth)acrylic alkyl ester.

54. The rechargeable lithium battery according to claim 52, wherein the water soluble agent for increasing viscosity is a cellulose-based compound.

55. The rechargeable lithium battery according to claim 54, wherein the cellulose-based compound is selected from the group consisting of carboxy methyl cellulose, hydroxyl propyl cellulose, hydroxyl propyl methyl cellulose, hydroxyl ethyl cellulose, hydroxyl propyl ethyl cellulose, methyl cellulose and alkaline salts thereof.

56. A rechargeable lithium battery, comprising:

an electrolyte comprising a first additive having an oxidation potential from 4.1 to 4.5V, a second additive having an oxidation potential from 4.5 to 5.0V, a non-aqueous organic solvent, and a lithium salt;

a positive electrode comprising a positive active material capable of reversibly intercalating and deintercalating lithium ions; and

a negative electrode capable of reversibly intercalating and deintercalating lithium ions,

wherein at least one of the positive electrode and a negative electrode comprises a water soluble binder and a water soluble agent for increasing viscosity.

57. The rechargeable lithium battery according to claim 56, wherein the first additive comprises a compound represented by Formula 2:

58. The rechargeable lithium battery according to claim 56, wherein the second additive comprises a compound represented by Formula 5:

59. The rechargeable lithium battery according to claim 56, wherein the positive active material comprises lithiated intercalation oxides.

60. The rechargeable lithium battery according to claim 56, wherein the negative active material is selected from the group consisting of crystalline carbon, amorphous carbon, a carbon complex, and lithium metal.

61. The rechargeable lithium battery according to claim 60, wherein the negative active material is crystalline carbon.

62. The rechargeable lithium battery according to claim 61, wherein the negative active material is crystalline carbon having an Lc (crystallite size) of 150 Å

or more, a d(002) of between 3.35 and 3.38 Å

, a true density of 2.2 g/cm³ or more, a BET (specific surface area) of between 0.5 and 50 m²/g, and an average particle diameter (D50) of between 1 and 30 μ

m.

63. The rechargeable lithium battery according to claim 60, wherein the negative active material has an intensity ratio Ra I(I(1360 cm⁻

1)/l(1580 cm<sup>−

1</sup>)) of a Raman Spectroscopy peak intensity I(1360) at a (1360) plane to an Raman Spectroscopy peak intensity I(1590) at a (1590) plane of 0.05 or more.

64. The rechargeable lithium battery according to claim 60, wherein the negative active material has an X-ray diffraction peak intensity ratio I(I(110)/I(002)) of an X-ray diffraction peak intensity (110) at a (110) plane to an X-ray diffraction peak intensity I(002) at a (002) plane of 0.2 or less.

65. The rechargeable lithium battery according to claim 60, wherein at least one of the positive electrode and the negative electrode comprises a water soluble binder and a water soluble thickener.

66. The rechargeable lithium battery according to claim 56, wherein the water soluble binder is selected from the group consisting of styrene-butadiene rubber, polysodium acrylate, copolymers of propylene and C₂-C₈ olefins and copolymers of (meth)acrylic acids and (meth)acrylic alkyl esters.

67. The rechargeable lithium battery according to claim 56, wherein the water soluble thickener is a cellulose compound.

68. The rechargeable lithium battery according to claim 67, wherein the cellulose compound is selected from the group consisting of carboxy methyl cellulose, hydroxyl propyl cellulose, hydroxyl propyl methyl cellulose, hydroxyl ethyl cellulose, hydroxyl propyl ethyl cellulose, methyl cellulose and alkaline salts thereof.