Active material, anode layer, battery, and methods for producing these

Patent metadata

Field	Value
Publication number	US-11967715-B2
Application number	US-202117210746-A
Country	US
Kind code	B2
Filing date	Mar 24, 2021
Priority date	Mar 27, 2020
Publication date	Apr 23, 2024
Grant date	Apr 23, 2024

Abstract

A main object of the present disclosure is to provide an active material wherein a volume variation due to charge/discharge is small. The present disclosure achieves the object by providing an active material comprising a silicon clathrate II type crystal phase, and having a composition represented by Na x Si 136 , wherein 1.98<x<2.54.

First claim

What is claimed is:

1. A method for producing an active material comprising a silicon clathrate II type crystal phase, and having a composition represented by Na x Si 136 , wherein 1.98<x<2.54, the method comprising:
a preparing step of preparing an intermediate including a silicon clathrate II type crystal phase and having a composition represented by Na y Si 136 , wherein 8≤y≤21,
an alloying step of obtaining an alloy compound by alloying the intermediate and a Li based material by mixing the intermediate and the Li based material,
a Li removing step of removing Li from the alloy compound by reacting the alloy compound with a Li extracting material, and obtaining a porous compound including a void inside a primary particle, and
a Na removing step of removing Na from the porous compound by a heat treatment.

2. A method for producing an anode layer, the method comprising:
an active material producing step of producing an active material by the method for producing an active material according to claim 1 , and
an anode layer forming step of forming an anode layer by using the active material.

3. A method for producing a battery, the method comprising:
an active material producing step of producing an active material by the method for producing an active material according to claim 1 , and
an anode layer forming step of forming an anode layer by using the active material.

4. The method for producing an active material according to claim 1 ,
wherein the “x” satisfies 2.30≤x≤2.50.

5. The method for producing an active material according to claim 1 , wherein the Li based material includes at least one kind of a simple substance of Li, and a Li alloy.

6. The method for producing an active material according to claim 1 , wherein a ratio (Li/Si) of Li included in the Li based material to Si included in the intermediate is 0.5 or more, and 3 or less.

7. The method for producing an active material according to claim 1 , wherein the Li extracting material includes a liquid.

8. The method for producing an active material according to claim 1 , wherein the Li extracting material includes at least one kind of a primary alcohol, a secondary alcohol, a tertiary alcohol, a phenolic, a glycol, a glycol ether, a pyranose, a furanose, a glucose, a fructose, a polysaccharide, and an acid.

9. The method for producing an active material according to claim 1 , wherein the Li extracting material includes at least ethanol.

10. The method for producing an active material according to claim 1 , wherein a temperature of the heat treatment is from 280° C. to 500° C.

11. The method for producing an active material according to claim 1 , wherein a time of the heat treatment is from 1 hour to 50 hours or less.

12. The method for producing an active material according to claim 1 , wherein a void ratio of the void is 4% or more, 40% or less.

13. The method for producing an active material according to claim 1 , wherein, as peaks of the silicon clathrate II type crystal phase, peak “A” at a position of 2θ=20.09°±0.50° and peak “B” at a position of 2θ=31.72°±0.50° are observed in X-ray diffraction measurement using a CuKαray, and
when an intensity of the peak “A” is regarded as I A , an intensity of the peak “B” is regarded as I B , and a maximum intensity in 2θ=22° to 23° is regarded as I M , I A /I M and I B /I M are respectively more than 1.

14. The method for producing an active material according to claim 13 , wherein the I A /I M satisfies 1.02<I A /I M and the I B /I M satisfies 1.03<I B /I M .

Assignees

• Toyota Motor Co Ltd

Inventors

• Otaki Mitsutoshi
• Yoshida Jun
• Suzuki Kazuhiro
• Harata Masanori

Classifications

• H01M4/58 Primary

  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 title

• H01M4/0495

  Chemical alloying · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• C01B33/021 Primary

  Preparation (chemical coating from the vapour phase C23C16/00) · CPC title

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title