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

Patent metadata

Field	Value
Publication number	US-10522824-B2
Application number	US-201515327744-A
Country	US
Kind code	B2
Filing date	Jul 21, 2015
Priority date	Jul 23, 2014
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

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. A method of preparing silicon-based active material particles, the method comprising:
providing silicon powders;
preparing a pre-pulverization mixture by dispersing the silicon powders in an oxidant solvent;
forming silicon particles by refining the silicon powders of the pre-pulverization mixture by applying mechanical compression and shearing stress to the silicon powders;
forming silicon-based active material particles by forming a chemical oxidation layer on the refined silicon particles by using the oxidant solvent while applying the mechanical compression and shearing stress, to provide a resulting product comprising the silicon-based active material particles; and
yielding the silicon-based active material particles by drying the resulting product,
wherein the silicon-based active material particles have a silicon crystal domain size of less than 50 nm.

2. The method of claim 1 , wherein the oxidant solvent comprises water, de-ionized water, an alcoholic solvent or a mixture of two or more thereof.

3. The method of claim 2 , wherein the alcoholic solvent comprises any one of ethyl alcohol, methyl alcohol, glycerol, propylene glycol, isopropyl alcohol, isobutyl alcohol, polyvinyl alcohol, cyclohexanol, octyl alcohol, decanol, hexatecanol, ethylene glycol, 1,2-octane diol, 1,2-dodecane diol, and 1,2-hexadecane diol, or a mixture thereof.

4. The method of claim 2 , wherein the alcoholic solvent is ethyl alcohol.

5. The method of claim 1 , wherein the applying of the mechanical compression and shearing stress is performed in a mill-pulverizing operation using a mixture of abrasive particles and the oxidant solvent.

6. The method of claim 1 , wherein the applying of the mechanical compression and shearing stresses is achieved by a grinding technique for providing the pre-pulverization mixture between a spinning abrasive plate and a fixed plate and performing pressing and polishing simultaneously.

7. The method of claim 1 , wherein the 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 Equation 1 below:

Circularity
=

2
⁢

π
⁢

⁢
A

P

[

Equation
⁢

⁢
1

]

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

8. The method of claim 1 , wherein the core of the silicon particle has a solid-type shape, a fiber-type shape, or a tube-type shape.

9. The method of claim 1 , wherein the area of the {110} surface of the core of the silicon particle is greater than the area of the {100} surface and the area of the {111} surface.

10. The method of claim 9 , wherein the {110} surface of the core of the silicon particle is a pulverized surface of a polished surface.

11. The method of claim 1 , wherein an average diameter of the silicon-based active material particles is in the range of 30 nm to 300 nm.

12. The method of claim 1 , wherein oxygen content of the silicon-based active material particles with respect to the total weight of the silicon-based active material particles is limited to from 9 wt % to 20 wt %.

13. The method of claim 1 , wherein a conductive layer is further formed on the chemical oxidation layer.

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

• H01M4/48

  of inorganic oxides or hydroxides · CPC title

• H01M4/38 Primary

  of elements or alloys · CPC title

• H01M4/00

  Electrodes · CPC title

• H01M10/0525

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

• H01M4/625

  Carbon or graphite · CPC title