Negative electrode active material for electric device and electric device using the same

Patent metadata

Field	Value
Publication number	US-10340519-B2
Application number	US-201615774948-A
Country	US
Kind code	B2
Filing date	Nov 10, 2016
Priority date	Nov 10, 2015
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

To provide a means capable of improving the cycle durability of an electric device such as a lithium ion secondary battery. A negative electrode active material containing a silicon-containing alloy having ternary alloy composition represented by Si—Sn-M (M is one or two or more transition metal elements) or quaternary alloy composition represented by Si—Sn-M-Al (M is one or two or more transition metal elements) and having a structure wherein an a-Si phase containing amorphous or low crystalline silicon containing tin in a silicon crystal structure in form of a solid solution is dispersed in a silicide phase containing a silicide of a transition metal as a main component is used in an electric device. The negative electrode active material improves the cycle durability of an electric device such as a lithium ion secondary battery.

First claim

The invention claimed is:

1. A negative electrode active material for electric device comprising a silicon-containing alloy having
a composition represented by the following Chemical Formula (1):
Si x Sn y M z Al w A a   (1)

wherein A is unavoidable impurities, M is one or two or more transition metal elements, x, y, z, w and a represent values of percent by mass, wherein 0<y<100, 0<z<100, 0≤w<100, and x and a are remainders), and
a structure wherein an a-Si phase containing amorphous or low crystalline silicon containing tin in a silicon crystal structure in form of a solid solution is dispersed in a silicide phase containing a silicide of a transition metal as a main component.

2. The negative electrode active material for electric device according to claim 1 , wherein a size of a periodic array region (MRO) in an a-Si phase by TEM-MRO analysis is 3.2 nm or less.

3. The negative electrode active material for electric device according to claim 2 , wherein the size of the periodic array region (MRO) is 1.6 nm or less.

4. The negative electrode active material for electric device according to claim 1 , wherein a diameter of the silicide phase is larger than a diameter of the a-Si phase.

5. The negative electrode active material for electric device according to claim 4 , wherein the diameter of the silicide phase is 50 nm or less and the diameter of the a-Si phase is 10 nm or less.

6. The negative electrode active material for electric device according to claim 5 , wherein the diameter of the silicide phase is 30 nm or less and the diameter of the a-Si phase is from 5 to 10 nm.

7. The negative electrode active material for electric device according to claim 1 , wherein the silicide of a transition metal is TiSi 2 and the a-Si phase is amorphous.

8. The negative electrode active material for electric device according to claim 1 , wherein w=0, 60≤x≤67, 5≤y≤10, and 28≤z≤30.

9. The negative electrode active material for electric device according to claim 8 , wherein a value of a ratio (m 2 /m 1 ) of a mass (m 2 ) of the silicide phase to a mass (m 1 ) of an available-Si phase in the silicon-containing alloy is 1.78 or more.

10. The negative electrode active material for electric device according to claim 9 , wherein a value of a ratio (m 2 /m 1 ) of a mass (m 2 ) of the silicide phase to a mass (m 1 ) of an available-Si phase in the silicon-containing alloy is 1.97 or more.

11. The negative electrode active material for electric device according to claim 1 , wherein 60≤x≤69, 1.5≤y≤8, 28≤z≤31, and 0.3≤w≤3.

12. The negative electrode active material for electric device according to claim 11 , wherein a value of a ratio (m 2 /m 1 ) of a mass (m 2 ) of the silicide phase to a mass (m 1 ) of an available-Si phase in the silicon-containing alloy is 1.75 or more.

13. The negative electrode active material for electric device according to claim 12 , wherein a value of a ratio (m 2 /m 1 ) of a mass (m 2 ) of the silicide phase to a mass (m 1 ) of an available-Si phase in the silicon-containing alloy is 1.85 or more.

14. The negative electrode active material for electric device according to claim 11 , wherein a ratio of a mass (m 1 ) of an available-Si phase to 100% by mass of the silicon-containing alloy is 33% by mass or more.

15. The negative electrode active material for electric device according to claim 11 , wherein it is satisfied that m 1 ≥61−14.3×(m 2 /m 1 ) where m 1 and m 2 denote a mass of an available-Si phase and a mass of the silicide phase in the silicon-containing alloy, respectively.

16. A method of producing the negative electrode active material for electric device according to claim 1 , the method comprising:
fabricating a quenched thin strip from a parent alloy having the same composition as a composition of the silicon-containing alloy by a liquid quenching solidification method; and
subjecting the quenched thin strip to a mechanical alloying treatment to obtain the negative electrode active material for electric device containing a silicon-containing alloy.

17. A method of producing the negative electrode active material for electric device according to claim 1 , the method comprising:
subjecting a powder of a parent alloy having the same composition as a composition of the silicon-containing alloy to a mechanical alloying treatment using a ball mill apparatus to apply a centrifugal force of 20 [G] or more to obtain the negative electrode active material for electric device containing a silicon-containing alloy.

18. The method of producing a negative electrode active material for electric device according to claim 17 , wherein time for the mechanical alloying treatment is 45 hours or shorter.

19. A negative electrode for electric device, comprising the negative electrode active material for electric device according to claim 1 .

20. An electric device comprising the negative electrode for electric device according to claim 19 .

21. The method of producing a negative electrode active material for electric device according to claim 17 , wherein the ball mill apparatus is a stirring ball mill apparatus.

Assignees

• Nissan Motor

Inventors

• Chiba Nobutaka
• Kaburagi Tomohiro
• Yoshioka Youichi
• Watanabe Manabu
• Arai Masaya

Classifications

• H01M4/463

  Aluminium based · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/04

  Processes of manufacture in general · CPC title

• H01M4/387

  Tin or alloys based on tin · CPC title

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title