LITHIUM SECONDARY BATTERY AND ACTIVE MATERIAL FOR NEGATIVE ELECTRODE IN LITHIUM SECONDARY BATTERY

• US 20020146623A1
• Filed: 09/10/1999
• Published: 10/10/2002
• Est. Priority Date: 09/11/1998
• Status: Active Grant

• Current Assignee: Nippon Steel Corporation
• Original Assignee: Nippon Steel Corporation
• Inventors: HAMADA, TAKESHI, SHOJI, HIROMASA, SUGIURA, TSUTOMU, SUZUKI, KIMIHITO, KONO, TARO
• Granted Patent: US 6,555,272 B2
• Time in Patent Office: Days
• US Class Current: 429/218.1
• 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 10/0564 the electrolyte being constituted of organic materials only
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 4/02 Electrodes composed of, or comprising, active material
• CPC Class Codes: H01M 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/364 as mixtures
• CPC Class Codes: H01M 4/38 of elements or alloys
• CPC Class Codes: H01M 4/58 of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A lithium secondary battery comprising a positive electrode active material, a negative electrode active material, and a non-aqueous electrolyte is disclosed. The negative electrode active material is a powder of a silicon material containing boron and has a boron content in the range of 0.1-50 wt. %.

Claims

1. A negative electrode active material for use in a lithium secondary battery;

which comprises a powder of boron containing silicon material, wherein the boron content in said silicon material is in the range of 0.1-50 wt. %.

2. A negative electrode active material according to claim 1, wherein said negative electrode active material has a 50% cumulative diameter (d₅₀) is in the range of 1-100 μ

m.

3. A negative electrode active material according to claim 1, wherein said negative electrode active material has a ratio I(SiB₄:

021)/I(Si;

111) of the peak intensity I(SiB₄;

021) of the diffraction line from the (021) plane of SiB₄ to the peak intensity I(Si;

111) of the diffraction line from the (111) plane of Si, which are found in an analysis of the active material by the X-ray wide angle diffraction method, being not more than 1.

4. A negative electrode active material for use in a lithium secondary battery;

which comprises a powder of a carbon material and a powder of a boron containing silicon material, which are mixed together, wherein the boron content in said silicon material is in the range of 0.1-50 wt. %, and wherein said carbon material is one of carbon material containing boron and carbon material containing no boron.

5. A negative electrode active material for a lithium secondary battery according to claim 4, wherein said negative electrode active material has a 50% cumulative diameter (d₅₀) is in the range of 1-100 μ

m.

6. A negative electrode active material for a lithium secondary battery according to claim 4, wherein said negative electrode active material has a ratio I(SiB₄:

021)/I(Si;

111) of the peak intensity I(SiB₄;

021) of the diffraction line from the (021) plane of SiB₄ to the peak intensity I(Si;

111) of the diffraction line from the (111) plane of Si, which are found in an analysis of the active material by the X-ray wide angle diffraction method, being not more than 1.

7. A negative electrode active material for a lithium secondary battery according to claim 4, wherein said powder of carbon material is a powder of a carbon material containing no boron, and in the diffraction peaks of said mixed powder measured by the wide angle X-ray diffraction method, the peak intensity, I(C:

101), of the diffraction line from the (101) plane of carbon and the peak intensity, I(C;

100), of the diffraction line from the (100) plane of carbon are such that the ratio of said two peak intensities, I(C;

101)/I(C;

100), is not less than 1.

8. A negative electrode active material for a lithium secondary battery according to claim 4, wherein said powder of carbon material is a powder of a carbon material containing boron, and in the diffraction peaks of said mixed powder measured by the wide angle X-ray diffraction method, the peak intensity, I(C:

101), of the diffraction line from the (101) plane of carbon and the peak intensity, I(C;

100), of the diffraction line from the (100) plane of carbon are such that the ratio of said two peak intensities, I(C

     101)/I(C;

100), is not less than 2.

9. A lithium secondary battery which comprises a positive electrode active material, a negative electrode active material, and a non-aqueous electrolyte, wherein said negative electrode active material comprising a powder of a silicon material containing boron and said powdery silicon material having a boron content in the range of 0.1-50 wt. %.

10. A lithium secondary battery according to claim 9, wherein said negative electrode active material has a 50% cumulative diameter (d₅₀) in the range of 1-100 μ

m.

11. A lithium secondary battery according to claim 9, wherein said negative electrode active material is found by the wide angle X-ray diffraction method to have a peak intensity, I(Si:

111) of the diffraction line from the (111) plane of Si and a peak intensity, I(SiB₄;

021) of the diffraction line from the (021) plane of SiB₄ and the ratio of said two peak intensities, I(SiB₄;

021) /I(Si;

111), is not more than 1.

13. A lithium secondary battery according to claim 12, wherein said negative electrode active material has a 50% cumulative diameter (d₅₀) in the range of 1-100 μ

m.

14. A lithium secondary battery according to claim 12, wherein said negative electrode active material is found by the wide angle X-ray diffraction method to have a peak intensity, I(Si:

111) of the diffraction line from the (111) plane of Si and a peak intensity, I(SiB₄;

021) of the diffraction line from the (021) plane of SiB₄ and the ratio of said two peak intensities, I(SiB₄;

021)/I(Si;

111), is not more than 1.

15. A negative electrode active material for a lithium secondary battery according to claim 12, wherein said powder of carbon material is a powder of a carbon material containing no boron and in the diffraction peaks of said mixed powder measured by the wide angle X-ray diffraction method, the peak intensity, I(C:

101), of the diffraction line from the (101) plane of carbon and the peak intensity, I(C;

100), of the diffraction line from the (100) plane of carbon are such that the ratio of said two peak intensities, I(C;

101)/I(C;

100), is not less than 1.

16. A negative electrode active material for a lithium secondary battery according to claim 12, wherein said powder of carbon material is a powder of a carbon material containing boron and in the diffraction peaks of said mixed powder measured by the wide angle X-ray diffraction method, the peak intensity, I(C:

101), of the diffraction line from the (101) plane of carbon and the peak intensity, I(C;

100), of the diffraction line from the (100) plane of carbon are such that the ratio of said two peak intensities, I(C;

101)/I(C;

100), is not less than 2.

12. A lithium secondary battery which comprises a positive electrode active material, a negative electrode active material, and a non-aqueous electrolyte, wherein said negative electrode active material comprising a powder of a carbon material and a powder of a boron containing silicon material, which are mixed together, and said powder of the silicon material having a boron content in the range of 0.1-50 wt. % and wherein said carbon material is one of carbon material containing boron and carbon material containing no boron.