Method for preparing silicon-based active material particles for secondary battery and silicon-based active material particles

Patent metadata

Field	Value
Publication number	US-11196042-B2
Application number	US-201916439602-A
Country	US
Kind code	B2
Filing date	Jun 12, 2019
Priority date	Jul 23, 2014
Publication date	Dec 7, 2021
Grant date	Dec 7, 2021

Abstract

The present invention relates to a method for preparing silicon-based active material particles for a secondary battery and silicon-based active material particles. The method for preparing silicon-based active material particles according to an embodiment of the present invention comprises the steps of: providing silicon powder; dispersing the silicon powder into an oxidant solvent to provide a mixture prior to grinding; fine-graining the silicon powder by applying mechanical compression and shear stress to the silicon powder in the mixture prior to grinding to produce silicon particles; producing a layer of chemical oxidation on the fine-grained silicon particles with the oxidant solvent while applying mechanical compression and shear stress to produce silicon-based active material particles; and drying the resulting product comprising the silicon-based active material particles to yield silicon-based active material particles.

First claim

The invention claimed is:

1. Silicon-based active material particles, each of the particles comprising:
a core of a silicon particle, wherein the core has a silicon crystal domain size of less than 50 nm; and
a chemical oxidation layer formed on the core of the silicon particle,
wherein the oxygen content of the silicon-based active material particles with respect to the total weight of the silicon-based active material particles is from 9 wt % to 20 wt %, and
wherein an average particle size of the silicon-based active material particles is in a range of 30 nm to 300 nm.

2. The silicon-based active material particles of claim 1 , wherein the average particle size of the silicon-based active material particles is in a range of 30 nm to 200 nm.

3. The silicon-based active material particles of claim 2 , wherein a particle size of 90% of the silicon-based active material particles is 310 nm or less.

4. The silicon-based active material particles of claim 1 , wherein a conductive layer is further formed on the chemical oxidation layer.

5. The silicon-based active material particles of claim 4 , wherein the conductive layer is a carbon-based conductive layer.

6. The silicon-based active material particles of claim 5 , wherein the carbon-based conductive layer has a larger mole fraction of sp 2 carbon than sp 3 carbon.

7. The silicon-based active material particles of claim 5 , wherein the carbon-based conductive layer is a graphite layer, a soft carbon layer, a graphene layer, a crystalline carbon layer, or an amorphous carbon layer.

8. The silicon-based active material particles of claim 7 , wherein the carbon-based conductive layer has a larger mole fraction of sp 2 carbon than sp 3 carbon.

9. The silicon-based active material particles of claim 1 , wherein a thickness of the chemical oxidation layer is in a range of 2 nm to 30 nm.

10. The silicon-based active material particles of claim 1 , wherein a thickness of the chemical oxidation layer is in a range of 3 nm to 15 nm.

11. The silicon-based active material particles of claim 1 , wherein the silicon-based active material particles each have a flake-like shape.

12. The silicon-based active material particles of claim 1 , wherein the chemical oxidation layer is formed by refining silicon powder by applying mechanical compression and shearing stresses and, simultaneously, wet-forming the chemical oxidation layer on the cores of the silicon particles by using an oxidant solvent.

13. The silicon-based active material particles of claim 1 , wherein the oxygen content of the silicon-based active material particles with respect to a total weight of the silicon-based active material particles is from 14 wt % to 20 wt %.

14. The silicon-based active material particles of claim 1 , wherein a circularity of the silicon-based active material particles is equal to or greater than 0.5 and less than or equal to 0.9, and the circularity is determined according to the equation:

Circularity
=

2
⁢

π
⁢

⁢
A

P

wherein A denotes an area of projection of a 2-dimensionally projected particle and P denotes the circumferential length of the 2-dimensionally projected particle.

Assignees

• Nexeon Ltd

Inventors

• Cho Young Tai
• Choi Yong Gil
• Park Seung Chul
• Park Seon
• Seo Hee Young
• Park Jee Hye
• Lee Yong Eui
• Kim Chul Hwan

Classifications

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M10/0525

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

• C01P2006/40

  Electric properties · CPC title

• H01M4/625

  Carbon or graphite · CPC title