Negative electrode material comprising silicon flakes and preparing method of silicon flakes

Patent metadata

Field	Value
Publication number	US-2020119344-A1
Application number	US-201716082021-A
Country	US
Kind code	A1
Filing date	Aug 18, 2017
Priority date	Aug 18, 2016
Publication date	Apr 16, 2020
Grant date	—

Abstract

The present disclosure relates to a negative electrode material including, as an active material, silicon flakes with a hyperporous structure, represented by the following chemical formula 1:
x Si.(1− x )A  (1)
where 0.5≤x≤1.0, and A is an impurity, and includes at least one compound selected from the group consisting of Al 2 O 3 , MgO, SiO 2 , GeO 2 , Fe 2 O 3 , CaO, TiO 2 , Na 2 O K 2 O, CuO, ZnO, NiO, Zr 2 O 3 , Cr 2 O 3 and BaO, and a preparing method of the silicon flakes.

First claim

What is claimed is:

1 . A negative electrode material comprising, as an active material, silicon flakes with a hyperporous structure, represented by the following chemical formula 1:
x Si.(1 −x )A  (1)
where 0.5≤x≤1.0, and A is an impurity, and includes at least one compound selected from the group consisting of Al 2 O 3 , MgO, SiO 2 , GeO 2 , Fe 2 O 3 , CaO, TiO 2 , Na 2 O K 2 O, CuO, ZnO, NiO, Zr 2 O 3 , Cr 2 O 3 and BaO.

2 . The negative electrode material according to claim 1 , wherein the silicon flakes have a hyperporous structure including macropores having a pore size in the range of greater than 50 nm to 500 nm, mesopores having a pore size of greater than 2 nm to 50 nm, and micropores having a pore size of 0.5 nm to 2 nm.

3 . The negative electrode material according to claim 1 , wherein the silicon flakes have an average pore diameter of 100 nm to 150 nm.

4 . The negative electrode material according to claim 1 , wherein the silicon flakes have a porosity of 10% to 50% based on a total volume.

5 . The negative electrode material according to claim 1 , wherein the silicon flakes have a thickness of 20 to 100 nm.

6 . The negative electrode material according to claim 1 , wherein the silicon flakes have a size of 200 nm to 50 μm.

7 . The negative electrode material according to claim 1 , wherein the silicon flakes have a BET surface area of 70 m 2 /g to 250 m 2 /g.

8 . The negative electrode material according to claim 1 , wherein the silicon flakes further include carbon coating.

9 . The negative electrode material according to claim 8 , wherein the carbon coating has a thickness of 1 to 100 nm.

10 . A preparing method of the silicon flakes defined in claim 1 , comprising:
i) thermally treating a mixture of clay and a metal reducing agent at 500 to 800° C. for 30 minutes to 6 hours; ii) adding the thermally treated mixture to an acidic solution and stirring; and iii) obtaining silicon flakes with hyperporous structure from the stirred result.

11 . The method for preparing the silicon flakes according to claim 10 , further comprising:
iv) performing thermal treatment with providing carbon containing gas to the obtained silicon flakes.

12 . The method for preparing the silicon flakes according to claim 10 , wherein the clay includes a mineral selected from the group consisting of montmorillonite, mica, talc and their combination as a clay mineral.

13 . The method for preparing the silicon flakes according to claim 10 , wherein the metal reducing agent is a same metal as metal oxide except silicon oxide included in the clay.

14 . The method for preparing the silicon flakes according to claim 10 , wherein a mix ratio between the clay and the metal reducing agent in the i) step is adjusted such that a mole ratio between oxygen of silicon oxide included in the clay and the metal reducing agent is from 1:0.5 to 1:2.

15 . The method for preparing the silicon flakes according to claim 10 , wherein the stirring in the acidic solution in the ii) step comprises stirring in a first acidic solution; and stirring in a second acidic solution in a subsequent order.

16 . The method for preparing the silicon flakes according to claim 10 , wherein each of the first acidic solution and the second acidic solution in the ii) step is independently selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, hydrofluoric acid, perchloric acid, chloric acid, chlorous acid, hypochlorous acid, iodic acid, and their combination.

17 . The method for preparing the silicon flakes according to claim 15 , wherein the first acidic solution is hydrochloric acid, and the second acidic solution is hydrofluoric acid.

18 . The method for preparing the silicon flakes according to claim 11 , wherein the carbon containing gas is selected from acetylene gas, ethylene gas, propylene gas, methane gas, ethane gas, and their combination.

19 . The method for preparing the silicon flakes according to claim 11 , wherein the thermal treatment in the iv) step is performed at 500° C. to 1000° C. for 1 minute to 30 minutes.

Assignees

• Lg Chemical Ltd
• Ulsan Nat Inst Science & Tech Unist

Inventors

• Hwang Eui-Yong
• Park Soo-Jin
• Ryu Jae-Geon
• Kim Jang-Bae
• Chae Jong-Hyun
• Hong Dong-Ki

Classifications

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/366

  as layered products · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title