Negative electrode active material for nonaqueous electrolyte secondary battery and nonaqueous electrolyte socondary battery

• US 20040115535A1
• Filed: 09/23/2003
• Published: 06/17/2004
• Est. Priority Date: 09/26/2002
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Takami, Norio, Morita, Tomokazu
• Granted Patent: US 7,303,838 B2
• Time in Patent Office: Days
• US Class Current: 429/231.8
• 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 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 4/364 as mixtures
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention provides a negative electrode active material for nonaqueous electrolyte secondary battery, including carbonaceous particles and a Si phase dispersed in the carbonaceous particles, wherein a half width of a diffraction peak of (220) plane in powder X-ray diffraction is 1.5° or more and 8° or less, and an average size of the Si phase is less than 100 nm.

Claims

1. A nonaqueous electrolyte secondary battery comprising:

a positive electrode;

a negative electrode containing a negative electrode active material including carbonaceous particles and a Si phase dispersed in the carbonaceous particles; and

a nonaqueous electrolyte;

wherein the negative electrode active material is 1.5°

or more and 8°

or less in a half width of a diffraction peak derived from (220) plane of silicon in powder X-ray diffraction, and

an average size of the Si phase is less than 100 nm.

2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the average size of the Si phase is 1 nm or more and less than 100 nm.

3. The nonaqueous electrolyte secondary battery according to claim 1, wherein the average size of the Si phase is 2 nm or more and 50 nm or less.

4. The nonaqueous electrolyte secondary battery according to claim 1, wherein the half width is 2°

or more and 6°

or less.

5. The nonaqueous electrolyte secondary battery according to claim 1, wherein the carbonaceous particles satisfy the following formula (1):

0.2≦

(X₁/X₂)≦

2  

 

(1)

where the X₁ is a molar number of a silicon atom in the carbonaceous particles, and the X₂ is a molar number of a carbon atom in the carbonaceous particles.

6. The nonaqueous electrolyte secondary battery according to claim 1, wherein an average particle size of the carbonaceous particles is 5 μ

m or more and 100 μ

m or less.

7. The nonaqueous electrolyte secondary battery according to claim 1, wherein the carbonaceous particles further contain a silicon oxide phase.

8. The nonaqueous electrolyte secondary battery according to claim 7, wherein the silicon oxide phase contains at least one compound of SiO₂ and SiO.

9. The nonaqueous electrolyte secondary battery according to claim 7, wherein at least part of the silicon oxide phase is in contact with the Si phase.

10. The nonaqueous electrolyte secondary battery according to claim 7, wherein the carbonaceous particles satisfy the following formula (2):

0.6≦

(X₁/X₃)≦

1.5  

 

(2)

where the X₁ is a molar number of a silicon atom of the Si phase, and the X₃ is a molar number of a silicon oxide molecule of the silicon oxide phase.

11. A negative electrode active material for nonaqueous electrolyte secondary battery, including carbonaceous particles and a Si phase dispersed in the carbonaceous particles,

wherein a half width of a diffraction peak of (220) plane in powder X-ray diffraction is 1.5°

or more and 8°

or less, and

an average size of the Si phase is less than 100 nm.

12. The negative electrode active material for nonaqueous electrolyte secondary battery, according to claim 11, wherein the average size of the Si phase is 1 nm or more and less than 100 nm.

13. The negative electrode active material for nonaqueous electrolyte secondary battery, according to claim 11, wherein the half width is 2°

or more and 6°

or less.

14. The negative electrode active material for nonaqueous electrolyte secondary battery, according to claim 11, wherein an average particle size of the carbonaceous particles is 5 μ

m or more and 100 μ

m or less.

15. The negative electrode active material for nonaqueous electrolyte secondary battery, according to claim 11, wherein the carbonaceous particles further contain a silicon oxide phase.

16. The negative electrode active material for nonaqueous electrolyte secondary battery, according to claim 15, wherein the silicon oxide phase contains at least one compound of SiO₂ and SiO.

17. The negative electrode active material for nonaqueous electrolyte secondary battery, according to claim 15, wherein at least part of the silicon oxide phase is in contact with the Si phase.