Mixed lithium manganese oxide and lithium nickel cobalt oxide positive electrodes

• US 6,379,842 B1
• Filed: 10/06/1999
• Issued: 04/30/2002
• Est. Priority Date: 11/27/1996
• Status: Expired due to Term

• Current Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Original Assignee: PolyStor Corp.
• Inventors: Mayer, Steven T.
• Primary Examiner(s): CHANEY, CAROL DIANE
• Application Number:
  US09/413,744
• Time in Patent Office: 937 Days
• Field of Search: 429/231.1, 429/231.3, 429/218.1, 429/223, 429/224
• US Class Current: 429/231.3
• 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 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/133 Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
• 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: Y02E 60/10 Energy storage using batteries

Abstract

Positive electrodes including a lithium nickel cobalt metal oxide are disclosed. The lithium nickel cobalt metal oxides have the general formula Li_xNi_yCO_zM_nO₂, where M is selected from the group consisting of aluminum, titanium, tungsten, chromium, molybdenum, magnesium, tantalum, silicon, and combinations thereof, x is between about 0 and about 1 and can be varied within this range by electrochemical insertion and extraction, the sum of y+z+n is about 1, n ranges between above 0 to about 0.25, y and z are both greater than 0, and the ratio z/y ranges from above 0 to about 1/3. Also disclosed are composite positive electrodes including the above-described lithium nickel cobalt metal oxides together with a lithium manganese metal oxide of the formula Li_xMn_2−rM1_rO₄, where r is a value between 0 and 1 and M1 is chromium, titanium, tungsten, nickel, cobalt, iron, tin, zinc, zirconium, silicon, or a combination thereof.

Claims

1. A lithium insertion positive electrode comprising a mixture of two or more homogeneous lithium ion insertion materials,

wherein at least one of the homogeneous lithium ion insertion materials is a chemical compound of the formula Li_xNi_0.8Co_0.2O₂ having an α

-NaCrO₂ crystal structure, where x is between about 0 and about 1 and can be varied within this range by electrochemical insertion and extraction, and

wherein at least one of the homogeneous lithium ion insertion materials is a lithium manganese oxide chemical compound of the formula Li_xMn₂O₄, and

wherein the Li_xNi_0.8Co_0.2O₂ is present in the positive electrode at a concentration of between about 30 and 80 weight percent and the Li_xMn₂O₄ is present in the positive electrode at a concentration of between about 20 and 70 weight percent.

2. The positive electrode of claim 1, wherein the Li_xNi_0.8Co_0.2O₂ is present in the positive electrode at a concentration of between about 30 and 50 weight percent and the Li_xMn₂O₄ is present in the positive electrode at a concentration of between about 70 and 50 weight percent.

3. The positive electrode of claim 1, further comprising carbon as an electronic conductor.

4. The positive electrode of claim 1, wherein the chemical compound is a particulate material in which the particles have an average particle size of not greater than about 50 μ

m.

5. The positive electrode of claim 1, further comprising a current collector.

6. The positive electrode of claim 1, wherein the Li_xNi_0.8Co_0.2O₂ is present in the positive electrode at a concentration of about 40 weight percent and the Li_xMn₂O₄ is present in the positive electrode at a concentration of about 60 weight percent.

7. A lithium ion cell comprising:

(a) a cell container;

(b) a negative electrode provided within the cell container and capable of intercalating lithium during charge and deintercalating lithium during discharge;

(c) an electrolyte conductive to lithium ions and provided within said cell container; and

(d) a positive electrode provided within the cell container and capable of taking up lithium on discharge and releasing lithium on charge, the positive electrode including a mixture of

(i) a chemical compound of the formula Li_xNi_0.8Co_0.2O₂ having an α

-NaCrO₂ crystal structure, where x is between about 0 and about 1 and can be varied within this range by electrochemical insertion and extraction, and

(ii) a lithium manganese oxide chemical compound of the formula Li_xMn₂O₄, and

wherein the Li_xNi_0.8Co_0.2O₂ is present in the positive electrode at a concentration of between about 30 and 80 weight percent and the Li_xMn₂O₄ is present in the positive electrode at a concentration of between about 20 and 70 weight percent.

8. The lithium ion cell of claim 7, wherein the Li_xNi_0.8Co_0.2O₂ is present in the positive electrode at a concentration of between about 30 and 50 weight percent and the Li_xMn₂O₄ is present in the positive electrode at a concentration of between about 70 and 50 weight percent.

9. The lithium ion cell of claim 7, further comprising carbon as an electronic conductor.

10. The lithium ion cell of claim 7, wherein the chemical compound is a particulate material in which the particles have an average particle size of not greater than about 50 μ

m.

11. The lithium ion cell of claim 7, further comprising a current collector.

12. The lithium ion cell of claim 7, wherein the Li_xNi_0.8Co_0.2O₂ is present in the positive electrode at a concentration of about 40 weight percent and the Li_xMn₂O₄ is present in the positive electrode at a concentration of about 60 weight percent.

13. The lithium ion cell of claim 7, wherein the electrolyte includes one or more of the following:

propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ

-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl 1,3-dioxolane, diethyl ether, sulfolane, acetonitrile, propionitrile, glutaronitrile, dimethyl carbonate, diethyl carbonate, anisole, and mixtures thereof.

14. The lithium ion cell of claim 7, wherein the electrolyte includes one or more of the following salts:

LiN(SO₂CF₃)₂, LiN(SO₂C₂F₅)₂, LiAs₆, LiPF₆, LiBF₄, LiB(C₆H₅)₄, LiCl, LiBr, CH₃SO₃Li, and CF₃SO₃Li.

15. The lithium ion cell of claim 7, wherein the electrolyte includes a solvent mixture selected from the group consisting of (a) ethylene carbonate, dimethyl carbonate, and diethyl carbonate;

(b) ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate;

(c) ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate; and

(d) ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, and dimethyl carbonate.

16. The lithium ion cell of claim 7 wherein the negative electrode includes a mixture of graphitic carbon particles and non-graphitic carbon particles.

17. A lithium insertion positive electrode comprising a mixture of two or more homogeneous lithium ion insertion materials,

wherein at least one of the homogeneous lithium ion insertion materials is Li_xNi_0.8Co_0.2O₂ having an α

-NaCrO₂ crystal structure, where x is between about 0 and about 1 and can be varied within this range by electrochemical insertion and extraction, and

wherein at least one of the homogeneous lithium ion insertion materials is a lithium manganese oxide spinel, and

wherein the Li_xNi_0.8Co_0.2O₂ is present in the positive electrode at a concentration of between about 30 and 80 weight percent and the lithium manganese oxide is present in the positive electrode at a concentration of between about 20 and 70 weight percent.

18. The positive electrode of claim 17, wherein the Li_xNi_0.8Co_0.2O₂ is present in the positive electrode at a concentration of between about 30 and 50 weight percent and the lithium manganese oxide spinel is present in the positive electrode at a concentration of between about 50 and 70 weight percent.

19. The positive electrode of claim 17, wherein the Li_xNi_0.8Co_0.2O₂ is present in the positive electrode at a concentration of between bout 80 and 50 weight percent and the lithium manganese oxide spinel is present in the positive electrode at a concentration of between about 20 and 50 weight percent.

20. The positive electrode of claim 17, wherein the Li_xNi_0.8Co_0.2O₂ is present in the positive electrode at a concentration of about 40 weight percent and the lithium manganese oxide spinel is present in the positive electrode at a concentration of between about 60 weight percent.

21. The positive electrode of claim 17, wherein the lithium manganese oxide spinel has a stoichiometric excess of lithium.