Negative electrode active material for electric device

Patent metadata

Field	Value
Publication number	US-9325003-B2
Application number	US-201214368167-A
Country	US
Kind code	B2
Filing date	Nov 5, 2012
Priority date	Dec 27, 2011
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A negative electrode active material for an electric device includes an alloy containing, in terms of mass ratio, 35%≦Si≦78%, 7%≦Sn≦30%, 0%<Ti≦37% and/or 35%≦Si≦52%, 30%≦Sn≦51%, 0%<Ti≦35%, and inevitable impurities as a residue. The negative electrode active material can be obtained with a multi DC magnetron sputtering apparatus by use of, for example, silicon, tin and titanium as targets. An electric device employing the negative electrode active material can keep a high discharge capacity and ensure a high cycle property.

First claim

The invention claimed is:

1. A negative electrode active material for an electric device, comprising an alloy consisting of, in terms of mass ratio, 35%≦Si≦70% [35%≦Si≦68%], 7%≦Sn≦30%, 7%≦Ti≦37% or 35%≦Si≦52%, 30%≦Sn≦51%, 7%≦Ti≦35%, and inevitable impurities as a residue, wherein a composition of the alloy produces an initial discharge capacity greater than 1000 mAh/g and a discharge capacity retention after 50 cycles of 93% or greater.

2. The negative electrode active material for an electric device according to claim 1 , wherein the alloy consists of, in terms of mass ratio, 35%≦Si≦68%, 7%≦Sn≦30%, 18%≦Ti≦37% or 39%≦Si≦52%, 30%≦Sn≦51%, 7%≦Ti≦20%, and inevitable impurities as a residue.

3. The negative electrode active material for an electric device according to claim 1 , wherein the alloy consists of, in terms of mass ratio, 46%≦Si≦58%, 7%≦Sn≦21%, 24%≦Ti≦37%, and inevitable impurities as a residue.

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

5. An electric device comprising the negative electrode for an electric device according to claim 4 .

6. The electric device according to claim 5 that is a lithium ion secondary battery.

7. A negative electrode active material for an electric device, comprising an alloy containing, in terms of mass ratio, 35%≦Si≦68%, 7%≦Sn≦30%, 18%≦Ti≦37%, or 35%≦Si≦52%, 30%≦Sn≦51%, 7%≦Ti≦35%, and inevitable impurities as a residue, wherein a composition of the alloy produces an initial discharge capacity greater than 1000 mAh/g and a discharge capacity retention after 50 cycles of 93% or greater.

8. The negative electrode active material for an electric device according to claim 7 , wherein the alloy contains, in terms of mass ratio, 46%≦Si≦58%, 7%≦Sn≦21%, 24%≦Ti≦37%, and inevitable impurities as a residue.

Assignees

• Nissan Motor

Inventors

• Watanabe Manabu
• Tanaka Osamu
• Yoshida Masao

Classifications

• C23C14/35

  by application of a magnetic field, e.g. magnetron sputtering {(C23C14/3457 takes precedence)} · CPC title

• H01M4/387

  Tin or alloys based on tin · CPC title

• C22C30/04

  containing tin or lead · CPC title

• H01M4/38

  of elements or alloys · CPC title

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title