Silicon oxide and method of preparing the same

Patent metadata

Field	Value
Publication number	US-9601768-B2
Application number	US-201414224955-A
Country	US
Kind code	B2
Filing date	Mar 25, 2014
Priority date	Nov 30, 2012
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

The present invention relates to a method of preparing silicon oxide, in which the amounts of silicon and oxygen are appropriately controlled by decreasing the amount of the oxygen from silicon oxide containing a relatively large amount of oxygen, silicon oxide prepared by the method, and a secondary battery including the same. According to the method of preparing silicon oxide, silicon oxide (first silicon oxide) including a relatively large amount of oxygen is heat treated in a reducing atmosphere to decrease the amount of the oxygen in the silicon oxide (first silicon oxide) and to prepare silicon oxide (second silicon oxide) including silicon and oxygen in an appropriate amount (Si:SiO 2 =1:0.7-0.98), thereby improving capacity and initial efficiency and securing stability and cycle properties (lifetime characteristics) of the secondary battery.

First claim

The invention claimed is:

1. A method of preparing silicon oxide for anode active material, comprising:
providing a first silicon oxide in a reactor in a reaction chamber, and heat treating under a reducing atmosphere to prepare a second silicon oxide,
wherein the first silicon oxide is SiO x (0<x<2), and the second silicon oxide is SiO y , where y<x and 0.7<y<0.98,
wherein the heat treating is performed at a temperature ranging from 800 ° C. to 1,000 ° C. and the temperature is maintained for 10 to 20 hours, and
wherein a crystal size of silicon (Si) in the second silicon oxide is in a range of 0.2 nm to 5 nm.

2. The method of preparing silicon oxide for anode active material of claim 1 , wherein SiO x in the first silicon oxide satisfies 0.9<x<1.5.

3. The method of preparing silicon oxide for anode active material of claim 1 , wherein the reducing atmosphere is created by supplying at least one reducing gas selected from the group consisting of H 2 , NH 3 and CO, or a mixture gas of the reducing gas and an inert gas.

4. The method of preparing silicon oxide for anode active material of claim 3 , wherein the reducing gas or the mixture gas is supplied by a flow rate of 1 sccm to 1,000 sccm.

5. The method of preparing silicon oxide for anode active material of claim 1 , wherein the reducing atmosphere is created by providing at least one material selected from the group consisting of an activated carbon, tantalum and molybdenum in a separate vessel in the reaction chamber.

6. Silicon oxide for anode active material prepared by the method according to claim 1 ,
wherein the silicon oxide is SiO y , where 0.7<y<0.98, and
wherein a crystal size of sillicon (Si) in the silicon oxide is in a range of 0.2 nm to 5 nm.

7. The silicon oxide for anode active material of claim 6 , wherein a full width at half-maximum (FWHM) of the silicon oxide in a range of 25 °<2θ<31 ° in a graph of X-ray diffraction (XRD) analysis using Cu—Kα is in a range of 1.5 ° to 2.5 °.

8. The silicon oxide for anode active material of claim 6 , wherein the silicon oxide has a g value measured by using an electron spin resonance (ESR) spectrometer in a range of 2.0015 to 2.0055.

9. A lithium secondary battery comprising an anode including an anode active material containing the silicon oxide for anode active material according to claim 6 , a cathode, a separator disposed between the anode and the cathode, and an electrolyte.

Assignees

• Lg Chemical Ltd

Inventors

• Lim Byung Kyu
• Jung Sang Yun
• Park Cheol Hee
• Jeong Han Nah
• Kim Je Young
• Lee Yong Ju
• Kim Hyun Chul

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M4/049

  Manufacturing of an active layer by chemical means · CPC title

• Y02P70/54

  Cross-Sectional Technologies · mapped topic

• H01M4/48 Primary

  of inorganic oxides or hydroxides · CPC title

• H01M4/485

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