Lithium-doped silicon-based oxide negative electrode active material, method of preparing the same, and negative electrode and secondary battery including the same

Patent metadata

Field	Value
Publication number	US-11923540-B2
Application number	US-202117383619-A
Country	US
Kind code	B2
Filing date	Jul 23, 2021
Priority date	Jul 29, 2020
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

Provided are a negative electrode active material which includes a negative electrode active material particles which includes a silicon oxide (SiO x , 0<x≤2); and at least one lithium silicate selected from Li 2 SiO 3 , Li 2 Si 2 O 5 , and Li 4 SiO 4 in at least a part of the silicon oxide. The negative electrode active material has a content of a nitrogen element according to X-ray photoelectron spectroscopy (XPS) of 1.45 atom % or less. Also provided are a negative electrode and a lithium secondary battery including the same.

First claim

What is claimed is:

1. A negative electrode active material comprising: negative electrode active material particles including a silicon oxide represented by SiO x , where 0<x≤2, and at least one lithium silicate selected from Li 2 SiO 3 , Li 2 Si 2 O 5 , and Li 4 SiO 4 in at least a part of the silicon oxide,
wherein the negative electrode active material has a content of a nitrogen element according to X-ray photoelectron spectroscopy (XPS) of 1.45 atom % or less, and
wherein the negative electrode active material particles include 70 to 85 wt % of the lithium silicate with respect to a total weight.

2. The negative electrode active material of claim 1 , wherein the nitrogen element is from at least one nitrogen compound selected from the group consisting of Li 2 NH, LiNH 2 , LiNO 3 , Li 3 N, NSiO 2 , NSi 2 O, and Si 3 N 4 .

3. The negative electrode active material of claim 1 , wherein the negative electrode active material particles include more than 0 wt % and 10 wt % or less of Li 4 SiO 4 with respect to the total weight.

4. A negative electrode comprising a negative electrode active material layer comprising: the negative electrode active material of claim 1 and a water-based binder.

5. A lithium secondary battery comprising: the negative electrode of claim 4 ; a positive electrode; a separator positioned between the negative electrode and the positive electrode; and an electrolyte.

6. A method of preparing the negative electrode active material of claim 1 , the method comprising:
performing a purge with an argon gas having a purity of 99.90% or more to create an inert atmosphere, and
mixing a silicon oxide and a Li precursor and performing heat treatment to prepare negative electrode active material particles including a silicon oxide represented by SiO x , where 0<x≤2, and at least one lithium silicate selected from Li 2 SiO 3 , Li 2 Si 2 O 5 , and Li 4 SiO 4 in at least a part of the silicon oxide.

7. The method of preparing a negative electrode active material of claim 6 , wherein the purge is performed at an argon gas flow velocity of 0.05 to 0.5 L/min.

8. The method of preparing a negative electrode active material of claim 6 , wherein the purge is performed for a purge time of 20 to 40 minutes.

Assignees

• Sk On Co Ltd

Inventors

• Park Eunjun
• Kim Joon-Sup
• Park Gwi Ok
• Kim Hansu
• Youn Donghan
• Chung Dong Jae

Classifications

• H01M4/483 Primary

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

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M10/0525

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

• H01M2004/027

  Negative electrodes · CPC title