Negative electrode active material and method for producing the same

Patent metadata

Field	Value
Publication number	US-2022013770-A1
Application number	US-201917296444-A
Country	US
Kind code	A1
Filing date	Nov 5, 2019
Priority date	Nov 28, 2018
Publication date	Jan 13, 2022
Grant date	—

Abstract

A negative electrode active material containing negative electrode active material particles. The negative electrode active material particles include silicon compound particles each containing an oxygen-containing silicon compound. The silicon compound particle contains at least one of Li2SiO3 and Li2Si2O5. The silicon compound particle has, in a Si K-edge spectrum obtained from a XANES spectrum: a peak P derived from the Li silicate and located near 1847 eV; and a peak Q gentler than the peak P and located near 1851 to 1852 eV. This provides a negative electrode active material that is capable of stabilizing a slurry when the negative electrode active material is used for a secondary battery, and capable of increasing the battery capacity by improving the initial efficiency.

First claim

1 - 10 . (canceled)

11 . A negative electrode active material containing negative electrode active material particles, wherein
the negative electrode active material particles comprise silicon compound particles each containing a silicon compound that contains oxygen, the silicon compound particle contains at least one of Li 2 SiO 3 and Li 2 Si 2 O 5 , and the silicon compound particle has, in a Si K-edge spectrum obtained from a XANES spectrum:
a peak P which is derived from the Li silicate and located near 1847 eV; and
a peak Q which is gentler than the peak P and located near 1851 to 1852 eV.

12 . The negative electrode active material according to claim 11 , wherein the peak Q is a peak derived from a cristobalite-type structure of SiO 2 .

13 . The negative electrode active material according to claim 11 , wherein the negative electrode active material has such an intensity ratio satisfying the following formula 1:
1.1 A≥B   (formula 1),
where A represents a peak maximum value of amorphous Si present near 466 cm −1 , and B represents a peak maximum value of crystalline Si present near 500 cm −1 , the values being obtained from a Raman spectrum when the negative electrode active material is measured by Raman spectroscopy.

14 . The negative electrode active material according to claim 12 , wherein the negative electrode active material has such an intensity ratio satisfying the following formula 1:
1.1 A≥B   (formula 1),
where A represents a peak maximum value of amorphous Si present near 466 cm −1 , and B represents a peak maximum value of crystalline Si present near 500 cm −1 , the values being obtained from a Raman spectrum when the negative electrode active material is measured by Raman spectroscopy.

15 . The negative electrode active material according to claim 13 , wherein the A and the B satisfy the following formula 2:
0.95 A≥B   (formula 2).

16 . The negative electrode active material according to claim 14 , wherein the A and the B satisfy the following formula 2:
0.95 A≥B   (formula 2).

17 . The negative electrode active material according to claim 15 , wherein
the A and the B satisfy the following formula 3, and a Si component contained as a simple substance in the negative electrode active material is substantially amorphous Si,
0.1 A≥B   (formula 3).

18 . The negative electrode active material according to claim 16 , wherein
the A and the B satisfy the following formula 3, and a Si component contained as a simple substance in the negative electrode active material is substantially amorphous Si,
0.1 A≥B   (formula 3).

19 . The negative electrode active material according to claim 11 , wherein the negative electrode active material satisfies the following formula 4:
0.2 C≥D   (formula 4),
where C represents a maximum peak value of Li 2 SiO 3 present near −75 ppm, and D represents a maximum peak value of Li 2 Si 2 O 5 present near −93 ppm, among peaks obtained when the negative electrode active material is measured by 29 Si-MAS-NMR.

20 . The negative electrode active material according to claim 12 , wherein the negative electrode active material satisfies the following formula 4:
0.2 C≥D   (formula 4),
where C represents a maximum peak value of Li 2 SiO 3 present near −75 ppm, and D represents a maximum peak value of Li 2 Si 2 O 5 present near −93 ppm, among peaks obtained when the negative electrode active material is measured by 29 Si-MAS-NMR.

21 . The negative electrode active material according to claim 13 , wherein the negative electrode active material satisfies the following formula 4:
0.2 C≥D   (formula 4),
where C represents a maximum peak value of Li 2 SiO 3 present near −75 ppm, and D represents a maximum peak value of Li 2 Si 2 O 5 present near −93 ppm, among peaks obtained when the negative electrode active material is measured by 29 Si-MAS-NMR.

22 . The negative electrode active material according to claim 14 , wherein the negative electrode active material satisfies the following formula 4:
0.2 C≥D   (formula 4),
where C represents a maximum peak value of Li 2 SiO 3 present near −75 ppm, and D represents a maximum peak value of Li 2 Si 2 O 5 present near −93 ppm, among peaks obtained when the negative electrode active material is measured by 29 Si-MAS-NMR.

23 . The negative electrode active material according to claim 15 , wherein the negative electrode active material satisfies the following formula 4:
0.2 C≥D   (formula 4),
where C represents a maximum peak value of Li 2 SiO 3 present near −75 ppm, and D represents a maximum peak value of Li 2 Si 2 O 5 present near −93 ppm, among peaks obtained when the negative electrode active material is measured by 29 Si-MAS-NMR.

24 . The negative electrode active material according to claim 16 , wherein the negative electrode active material satisfies the following formula 4:
0.2 C≥D   (formula 4),
where C represents a maximum peak value of Li 2 SiO 3 present near −75 ppm, and D represents a maximum peak value of Li 2 Si 2 O 5 present near −93 ppm, among peaks obtained when the negative electrode active material is measured by 29 Si-MAS-NMR.

25 . The negative electrode active material according to claim 17 , wherein the negative electrode active material satisfies the following formula 4:
0.2 C≥D   (formula 4),
where C represents a maximum peak value of Li 2 SiO 3 present near −75 ppm, and D represents a maximum peak value of Li 2 Si 2 O 5 present near −93 ppm, among peaks obtained when the negative electrode active material is measured by 29 Si-MAS-NMR.

26 . The negative electrode active material according to claim 18 , wherein the negative electrode active material satisfies the following formula 4:
0.2 C≥D   (formula 4),
where C represents a maximum peak value of Li 2 SiO 3 present near −75 ppm, and D represents a maximum peak value of Li 2 Si 2 O 5 present near −93 ppm, among peaks obtained when the negative electrode active material is measured by 29 Si-MAS-NMR.

27 . The negative electrode active material according to claim 11 , wherein the negative electrode active material particles have a median diameter of 2.0 μm or more and 12 μm or less.

28 . The negative electrode active material according to claim 11 , wherein the negative electrode active material particles each have a surface layer portion containing a carbon material.

29 . The negative electrode active material according to claim 28 , wherein the carbon material has an average thickness of 5 nm or more and 500 nm or less.

30 . A method for producing a negative electrode active material containing negative electrode active material particles, the method comprising steps of:
preparing silicon compound particles each containing a silicon compound that contains oxygen; inserting Li into the silicon compound particles to incorporate at least one of Li 2 SiO 3 and Li 2 Si 2 O 5 into the silicon compound particles so as to prepare the negative electrode active material particles; further selecting, from the prepared negative electrode active material particles, such negative electrode active material particles each having a peak P derived from the Li silicate and located near 1847 eV and a peak Q gentler than the peak P and located near 1851 to 1852 eV in a Si K-edge spectrum obtained from XANES spectra when the prepared negative electrode active material particles are subjected to XANES measurement; and using the se

Assignees

• Shinetsu Chemical Co

Inventors

• Hirose Takakazu
• Sakai Reiko
• Osawa Yusuke
• Takahashi Kohta
• Matsuno Takumi

Classifications

• C01P2004/60

  Particles characterised by their size · CPC title

• H01M4/483

  for non-aqueous cells (H01M4/485 takes precedence) · CPC title

• H01M4/485 Primary

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• C01B33/32

  Alkali metal silicates ({C01B33/24} , C01B33/26 take precedence) · CPC title