Nonaqueous lithium secondary battery with cyclability and/or high temperature safety improved

• US 20050100786A1
• Filed: 09/17/2004
• Published: 05/12/2005
• Est. Priority Date: 09/19/2003
• Status: Abandoned Application

• Current Assignee: LG Chem Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Shin, Sun Sik, Lee, Han Ho, Jang, Min Chul, Yeon, Jin Hee, Ryu, Duk Hyun, Jeong, Jun Yong, Ku, Cha Hun, Lee, Jae Hyun, Koo, Chang Wan
• Application Number:
  US10/944,572
• Publication Number:
  US 20050100786A1
• Time in Patent Office: Days
• US Class Current: 429/199
• 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 10/0566 Liquid materials
• CPC Class Codes: H01M 10/0567 characterised by the additives
• CPC Class Codes: H01M 10/0569 characterised by the solvents
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• 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 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 6/166 by the solute
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention provides: (i) a nonaqueous electrolyte for batteries, which is characterized by containing halogen; (ii) a nonaqueous electrolyte for batteries, which is characterized by containing pyrrol or its derivative and halogen; and (iii) a lithium secondary battery which is characterized by including the nonaqueous electrolyte (i) or (ii). The inventive lithium secondary battery has improvements in charge/discharge and cycle life characteristics at ambient and high temperatures, and/or storage characteristics and safety at high temperature.

Claims

1. A nonaqueous electrolyte for batteries, wherein the nonaqueous electrolyte further comprises halogen.

3. The nonaqueous electrolyte of claim 1, wherein the content of the halogen is 0.005-1% by weight.

5. The nonaqueous electrolyte of claim 1, wherein the halogen is selected from the group consisting of iodine, chlorine, bromine and a mixture of two or more thereof.

7. The nonaqueous electrolyte of claim 1, which comprises a lithium salt selected from the group consisting of LiClO₄, LiCF₃SO₃, LiPF₆, LiBF₄, LiAsF₆, and LiN(CF₃SO₂)₂, a mixture of two or more thereof.

8. The nonaqueous electrolyte of claim 1, wherein the electrolyte contains:

a cyclic carbonate selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), gamma-butyrolactone (GBL) and a mixture of two or more thereof;

or a linear carbonate selected from the group consisting of diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), methylpropyl carbonate (MPC) and a mixture of two or more thereof;

or both the cyclic carbonate and the linear carbonate.

9. A lithium secondary battery, comprising:

a) a positive electrode capable of storing and releasing lithium ions;

b) a negative electrode capable of storing and releasing lithium ions;

c) a porous separator; and

d) a nonaqueous electrolyte containing

i) a lithium salt; and

ii) a liquid electrolyte compound,

wherein the electrolyte is the nonaqueous electrolyte as claimed in claim 1.

10. The lithium secondary battery of claim 9, wherein the positive active material a) is a lithium transition metal oxide selected from the group consisting of LiCoO₂, LiNiO₂, LiMn₂O₄, LiN_1-XCo_XO₂ (0<

X<

1), and a mixture of two or more thereof.

11. The lithium secondary battery of claim 9, wherein the negative active material b) is carbon, lithium metal or alloy.

2. A nonaqueous electrolyte for batteries, wherein the nonaqueous electrolyte further comprises pyrrole or its derivative and halogen.

4. The nonaqueous electrolyte of claim 2, wherein the content of the pyrrole or its derivative is 0.01-0.5% by weight.

6. The nonaqueous electrolyte of claim 2, wherein the pyrrole derivative is selected from the group consisting of 2,5-dimethylpyrrole, 2,4-dimethylpyrrole, 2-acetyl N-methylpyrrole, 2-acetylpyrrole, N-methylpyrrole, and a mixture of two or more thereof.

12. The nonaqueous electrolyte of claim 2, wherein the content of the halogen is 0.005-1% by weight.

13. The nonaqueous electrolyte of claim 2, wherein the halogen is selected from the group consisting of iodine, chlorine, bromine and a mixture of two or more thereof.

14. The nonaqueous electrolyte of claim 2, which comprises a lithium salt selected from the group consisting of LiClO₄, LiCF₃SO₃, LiPF₆, LiBF₄, LiAsF₆, and LiN(CF₃SO₂)₂, a mixture of two or more thereof.

15. The nonaqueous electrolyte of claim 2, wherein the electrolyte contains:

a cyclic carbonate selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), gamma-butyrolactone (GBL) and a mixture of two or more thereof;

or a linear carbonate selected from the group consisting of diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), methylpropyl carbonate (MPC) and a mixture of two or more thereof;

or both the cyclic carbonate and the linear carbonate.