Electrolyte for lithium ion rechargeable battery and lithium ion rechargeable battery comprising the same

• US 7,981,551 B2
• Filed: 05/31/2005
• Issued: 07/19/2011
• Est. Priority Date: 05/31/2004
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Kim, Joong Heon, Lee, Sang Ho, Kim, Cheon Soo, Lee, Hyung Bok, Earmme, Tae Shik, Kim, Kwang Sup, Yeo, Kwang Soo, Lee, Chan Hee
• Primary Examiner(s): Ryan; Patrick
• Assistant Examiner(s): SIDDIQUEE, MUHAMMAD S
• Application Number:
  US11/139,981
• Publication Number:
  US 20050277027A1
• Time in Patent Office: 2,240 Days
• Field of Search: 429/326, 429/328, 429/329, 429/330, 429/332, 429/339, 429/340
• US Class Current: 429/326
• 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 10/0565 Polymeric materials, e.g. gel-type or solid-type
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 6/164 by the solvent
• CPC Class Codes: H01M 6/166 by the solute
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention relates to an electrolyte for a lithium ion rechargeable battery and a lithium ion rechargeable battery including the same. The electrolyte includes a non-aqueous organic solvent, a lithium salt, and triphenyl phosphate. A lithium ion rechargeable battery including the electrolyte has improved overcharge stability and shows excellent chemical properties including reducing swelling, high-temperature storage stability, and cycle life characteristics.

Claims

1. An electrolyte for a lithium ion rechargeable battery, consisting of:

a non-aqueous organic solvent;

a lithium salt;

at least one monomer selected from a group consisting of an acrylate monomer, epoxy monomer, isocyanate monomer and prepolymers thereof;

an organic peroxide or an azo-based polymerization initiator; and

triphenyl phosphate,

wherein the triphenyl phosphate has a concentration of 5 to 10 wt %, based on the total weight of the electrolyte.

2. The electrolyte of claim 1, wherein the lithium salt is at least one selected from a group consisting of LiPF₆, LiBF₄, LiSbF₆, LiAsF₆, LiClO₄, LiAlO₄, LiAlCl₄, LiCF₃SO₃, LiN(SO₂CF₃)₂, LiC₄F₉SO₃, LiN(SO₂C₂F₅)₂, LiN(C_xF_2x+1SO₂)(C_yF_2y+1SO₂) (wherein, each of x and y is an integer), LiCl and Lil.

3. The electrolyte of claim 2, wherein the lithium salt has a concentration in the range of 0.6M to 2.0M.

4. The electrolyte of claim 1, wherein the non-aqueous organic solvent is at least one selected from a group consisting of a carbonate, an ester, an ether, and a ketone.

5. The electrolyte of claim 4, wherein the carbonate is at least one selected from a group consisting of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethylmethyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, ethylene carbonate, propylene carbonate and butylene carbonate.

6. The electrolyte of claim 5, wherein the carbonate solvent is a mixed solvent of a cyclic carbonate and a linear chain carbonate.

7. The electrolyte of claim 4, wherein the non-aqueous organic solvent is a mixed solvent of a carbonate solvent and an aromatic hydrocarbon-based organic solvent.

8. The electrolyte of claim 7, wherein the aromatic hydrocarbon-based organic solvent is an aromatic compound represented by Formula 2:

9. The electrolyte of claim 8, wherein the aromatic hydrocarbon-based organic solvent is at least one solvent selected from a group consisting of benzene, fluorobenzene, chlorobenzene, toluene, fluorotoluene, trifluorotoluene, xylene, and mixtures thereof.

10. The electrolyte of claim 9, wherein a volume ratio of the carbonate solvent to the aromatic hydrocarbon-based organic solvent is between 1:

1 and 30;

1.

11. The electrolyte of claim 4, wherein the ether is tetrahydrofuran or 2-methyl tetrahydrofuran.

12. The electrolyte of claim 4, wherein the ester is at least one solvent selected from a group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate and γ

-butyrolactone.

13. The electrolyte of claim 4, wherein the ketone is polymethylvinyl ketone.

14. The electrolyte of claim 1, wherein the monomer has a concentration of about 0.1 to about 5 wt % based on a total weight of the electrolyte.

15. An electrolyte of claim 1, wherein the organic peroxide has a concentration of about 0.01 to about 1.0 wt % based on a total weight of the monomer.

16. The electrolyte of claim 1, wherein the peroxide is at least one peroxide selected from a group consisting of isobutyl peroxide, lauryl peroxide, lauroyl peroxide, dilauroyl peroxide, didecanoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, benzoyl peroxide, m-toluoyl peroxide, tert-butyl peorxy-2-ethyl hexanoate, tert-butyl peroxy pivalate, tert-butyl peroxy neodecanoate, diisopropyl peroxy dicarbonate, diethoxy peroxy dicarbonate, bis-(4-tert-butylcyclohexyl) peroxy dicarbonate, dimethoxy isopropyl peroxy dicarbonate, dicyclohexyl peroxy dicarbonate, and 3,3,5-trimethylhexanoyl peroxide.

17. A lithium ion rechargeable battery, comprising:

a cathode including a cathode active material that is capable of reversible lithium ion intercalation/deintercalation;

an anode including an anode active material that is capable of reversible lithium ion intercalation/deintercalation; and

an electrolyte,

wherein the electrolyte consists of;

a non-aqueous organic solvent;

a lithium salt;

at least one monomer selected from a group consisting of an acrylate monomer, epoxy monomer, isocyanate monomer and prepolymers thereof;

an organic peroxide or an azo-based polymerization initiator; and

triphenyl phosphate,

wherein the triphenyl phosphate has a concentration of 5 to 10 wt %, based on the total weight of the electrolyte.

18. The lithium ion rechargeable battery of claim 17, wherein the battery is a lithium ion polymer battery.