Active material, negative electrode layer, battery, and method for producing the same

Patent metadata

Field	Value
Publication number	US-2025309248-A1
Application number	US-202318863925-A
Country	US
Kind code	A1
Filing date	Mar 14, 2023
Priority date	May 11, 2022
Publication date	Oct 2, 2025
Grant date	—

Abstract

An active material includes silicon. The active material has voids inside primary particles, and a void volume X of voids having a pore diameter of 10 nm or less among the voids is 0.015 cc/g or more.

First claim

What is claimed is:

1 . An active material comprising silicon, wherein
the active material has voids inside primary particles, and a void volume X of voids having a pore diameter of 10 nm or less among the voids is 0.015 cc/g or more.

2 . The active material according to claim 1 , wherein the void volume X is 0.09 cc/g or less.

3 . The active material according to claim 1 , wherein a void volume Y of voids having a pore diameter of 50 nm or less among the voids is 0.05 cc/g or more and 0.25 cc/g or less.

4 . The active material according to claim 3 , wherein a ratio (X/Y) of the void volume X to the void volume Y is 0.17 or more and 0.41 or less.

5 . The active material according to claim 1 , wherein a void volume Z of voids having a pore diameter of 100 nm or less among the voids is 0.05 cc/g or more and 0.40 cc/g or less.

6 . The active material according to claim 5 , wherein a ratio (X/Z) of the void volume X to the void volume Z is 0.10 or more and 0.34 or less.

7 . The active material according to claim 1 , wherein the active material has a crystal phase of Type II silicon clathrate.

8 . The active material according to claim 7 , wherein:
a peak A at 2θ=20.09°±0.50° and a peak B at 2θ=31.72°±0.50° are observed as peaks of the crystal phase of the Type II silicon clathrate in X-ray diffraction measurement using CuKα rays; and when an intensity of the peak A is I A , an intensity of the peak B is I B , and a maximum intensity at 2θ=22° to 23° is I M , I A /I M is 1.75 or more and 10 or less, and I B /I M is 1.35 or more and 7 or less.

9 . The active material according to claim 1 , wherein the active material has a crystal phase of diamond-type silicon.

10 . A negative electrode layer comprising an active material including silicon, wherein
the active material has voids inside primary particles, and a void volume P of voids having a pore diameter of 10 nm or less among the voids is 0.015 cc/g or more.

11 . The negative electrode layer according to claim 10 , wherein the void volume P is 0.031 cc/g or less.

12 . The negative electrode layer according to claim 10 , wherein a void volume Q of voids having a pore diameter of 50 nm or less among the voids is 0.035 cc/g or more and 0.11 cc/g or less.

13 . The negative electrode layer according to claim 12 , wherein a ratio (P/Q) of the void volume P to the void volume Q is 0.22 or more and 0.39 or less.

14 . The negative electrode layer according to claim 10 , wherein a void volume R of voids having a pore diameter of 100 nm or less among the voids is 0.053 cc/g or more and 0.16 cc/g or less.

15 . The negative electrode layer according to claim 14 , wherein a ratio (P/R) of the void volume P to the void volume R is 0.14 or more and 0.30 or less.

16 . A battery comprising:
the negative electrode layer according to claim 10 ; a positive electrode layer; and an electrolyte layer disposed between the positive electrode layer and the negative electrode layer.

17 . A method for producing the active material according to claim 1 , the method comprising:
obtaining a Na—Si alloy by causing a sodium source and a silicon source to react with each other; and producing a silicon clathrate-type crystal phase by heating the Na—Si alloy to reduce an amount of sodium in the Na—Si alloy, wherein the producing the silicon clathrate-type crystal phase uses a scavenger to scavenge the sodium in the Na—Si alloy.

18 . A method for producing a negative electrode layer, the method comprising:
producing an active material by the method for producing the active material according to claim 17 ; and forming the negative electrode layer by using the active material.

19 . A method for producing a battery, the method comprising:
producing an active material by the method for producing the active material according to claim 17 ; and forming a negative electrode layer by using the active material.

Assignees

• Toyota Motor Co Ltd

Inventors

• Otaki Mitsutoshi
• Yoshida Jun
• Harata Masanori
• Eguchi Tatsuya
• Yamaguchi Yasuhiro
• Urabe Kota

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/0525

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

• Y02E60/10

  Energy storage using batteries · CPC title

• C01P2002/70

  defined by measured X-ray, neutron or electron diffraction data · CPC title

• H01M2004/027

  Negative electrodes · CPC title