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

Patent metadata

Field	Value
Publication number	US-10840506-B2
Application number	US-201616309848-A
Country	US
Kind code	B2
Filing date	Jun 16, 2016
Priority date	Jun 16, 2016
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

A negative electrode active material containing a Si-containing alloy having a composition to be represented by Chemical Formula (1): Si x Sn y M z Al w A a (in Chemical Formula (1) above, M is one or two or more transition metal elements, A is an unavoidable impurity, and x, y, z, w, and a represent values of percentage by mass, where y, z, and w are 2≤y≤10, 25≤z≤35, and 0.3≤w≤3, respectively, and x and a are remainder) is used in an electrical device, providing a means capable of improving the cycle durability of the electrical device such as a lithium ion secondary battery.

First claim

The invention claimed is:

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

wherein M is one or two or more transition metal elements selected from the group consisting of Ti, Zr, Ni, Cu, Mo, Nb, Sc, Co, Cr and Fe, A is an unavoidable impurity, and x, y, z, w, and a represent values of percentage by mass, wherein y, z, and w are 2≤y≤10, 25≤z≤35, and 0.3≤w≤3, respectively, and x and a are remainder, and x+y+z+w+a=100.

2. The negative electrode active material for an electrical device according to claim 1 , wherein an atomic ratio of Sn to Al in the Si-containing alloy is from 0.3:1 to 3:1.

3. The negative electrode active material for an electrical device according to claim 1 , wherein a microstructure of the Si-containing alloy has a first phase containing a silicide of a transition metal as a main component and a second phase containing Sn and Al in part and amorphous or low crystalline Si as a main component and further has a structure of which a part is composed of a plurality of the first phases which are independent and a part has a eutectic structure composed of the first phase and the second phase.

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

wherein M is one or two or more transition metal elements, A is an unavoidable impurity, and x, y, z, and w represent values of percentage by mass, wherein y, z, and w are 0<y<100, 0<z<100, and 0<w<100, respectively, and x and a are remainder), and
wherein a microstructure of the Si-containing alloy has a first phase containing a silicide of a transition metal as a main component and a second phase containing Sn and Al in part and amorphous or low crystalline Si as a main component and further has a structure of which a part is composed of a plurality of the first phases which are independent and a part has a eutectic structure composed of the first phase and the second phase.

5. The negative electrode active material for an electrical device according to claim 3 , wherein a modal radius A of the first phases which are independent in the microstructure is 250 nm or less.

6. The negative electrode active material for an electrical device according to claim 3 , wherein a ratio of a modal radius A of the first phases which are independent to a modal radius C of the second phases of the eutectic structure in the microstructure: D2 (modal radius A of the first phases which are independent/modal radius C of the second phases of eutectic structure) is 4.5 or less.

7. The negative electrode active material for an electrical device according to claim 3 , wherein a ratio of a modal radius B of the first phases to a modal radius C of the second phases in the eutectic structure: D3 (modal radius B of the first phases of the eutectic structure/modal radius C of the second phases of the eutectic structure) is 1 or less.

8. The negative electrode active material for an electrical device according to claim 1 , wherein M is Ti.

9. A method for producing the negative electrode active material for an electrical device according to claim 1 , the method comprising fabricating a rapidly quenched ribbon of a Si-containing alloy using a mother alloy having the same composition as that of the Si-containing alloy by a liquid quenching solidification method.

10. The production method according to claim 9 , wherein a critical cooling velocity F of liquid phase composition at the start of eutectic formation in the mother alloy composition is 3×10 8 K/sec or less.

11. The negative electrode active material for an electrical device according to claim 10 , wherein the critical cooling velocity F and a ratio E of silicide of a transition metal in the eutectic structure to silicide of all transition metals in the rapidly quenched ribbon in the Si-containing alloy satisfy E/F>2.2×10 −9 sec/K.

12. A negative electrode for an electrical device, comprising the negative electrode active material for an electrical device according to claim 1 .

13. An electrical device comprising the negative electrode for an electrical device according to claim 12 .

14. The negative electrode active material for an electrical device according to claim 1 , wherein a is less than 0.5 percent by mass.

15. The negative electrode active material for an electrical device according to claim 1 , wherein a is less than 0.1 percent by mass.

Assignees

• Nissan Motor

Inventors

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

Classifications

• C01P2004/04

  obtained by TEM, STEM, STM or AFM · CPC title

• H01M4/38

  of elements or alloys · CPC title

• C01P2004/03

  obtained by SEM · CPC title

• C01P2002/85

  by XPS, EDX or EDAX data · CPC title

• C22C28/00 Primary

  Alloys based on a metal not provided for in groups C22C5/00 - C22C27/00 · CPC title