Sulfur-doped silicon negative electrode material, method for producing same, lithium secondary battery negative electrode including negative electrode material, and lithium secondary battery comprising negative electrode

Patent metadata

Field	Value
Publication number	US-2021328214-A1
Application number	US-202017285316-A
Country	US
Kind code	A1
Filing date	Mar 6, 2020
Priority date	Mar 8, 2019
Publication date	Oct 21, 2021
Grant date	—

Abstract

A sulfur-doped silicon negative electrode material, a preparation method for a sulfur-doped silicon negative electrode material, a negative electrode for a lithium secondary battery comprising the sulfur-doped silicon negative electrode material, and a lithium secondary battery comprising the negative electrode, wherein the sulfur-doped silicon negative electrode material has an internal pore channel having an average width of 500 nm to 3 μm and an average external diameter of 1 μm to 5 μm.

First claim

1 . A sulfur-doped silicon negative electrode material which has an internal pore channel having an average width of 500 nm to 3 μm and has an average external diameter of 1 μm to 5 μm.

2 . The sulfur-doped silicon negative electrode material according to claim 1 , wherein the internal pore channel has a shape formed by sulfur-doped silicon particles.

3 . The sulfur-doped silicon negative electrode material according to claim 1 , wherein the sulfur-doped silicon negative electrode material is a material doped with sulfur, and
wherein the sulfur is doped in an amount of 0.1 at % to 5 at %.

4 . The sulfur-doped silicon negative electrode material according to claim 1 , wherein the sulfur-doped silicon negative electrode material has an electrical conductivity of 1 S/m to 6 S/m.

5 . The sulfur-doped silicon negative electrode material according to claim 1 , wherein the sulfur-doped silicon negative electrode material has a lithium ion diffusion coefficient of 10 −12 cm 2 /s to 10 −10 cm 2 /s.

6 . The sulfur-doped silicon negative electrode material according to claim 1 , wherein the sulfur-doped silicon negative electrode material has a porosity of 4% to 10%.

7 . A method for preparing a sulfur-doped silicon negative electrode material comprising the steps of:
(a) preparing a mixture by mixing silica, a metal reducing agent, a metal halide salt, and a sulfate compound; and (b) performing a reduction reaction on the mixture.

8 . The method for preparing the sulfur-doped silicon negative electrode material according to claim 7 , wherein in step (a), silica, the metal reducing agent, the metal halide salt, and the sulfate compound are mixed in a weight ratio of 5 14:12-14:62-67:7-19, respectively.

9 . The method for preparing the sulfur-doped silicon negative electrode material according to claim 7 , wherein in step (b), the reduction reaction is performed by heating the mixture to a temperature in a range of 200° C. to 270° C. under an inert atmosphere.

10 . The method for preparing the sulfur-doped silicon negative electrode material according to claim 7 , wherein in step (a), the sulfate compound is at least one selected from the group consisting of MgSO 4 , ZnSO 4 , BaSO 4 , Na 2 SO 4 , and NiSO 4 .

11 . The method for preparing the sulfur-doped silicon negative electrode material according to claim 7 , wherein in step (a), the metal reducing agent is at least one selected from the group consisting of Mg, Al, Ca, and Zn, and the metal halide salt is at least one selected from the group consisting of AlCl 3 , MgCl 2 , and ZnCl 2 .

12 . The method for preparing the sulfur-doped silicon negative electrode material according to claim 7 , further comprising a step of:
(c) dispersing the mixture in water to remove unreacted metal halide salt and sulfate compound after the reduction reaction of step (b) is completed.

13 . The method for preparing the sulfur-doped silicon negative electrode material according to claim 12 , further comprising a step of:
(d) removing the metal reducing agent and residual material by treating the mixture with an aqueous hydrochloric acid solution after performing step (c).

14 . The method for preparing the sulfur-doped silicon negative electrode material according to claim 7 further comprising a step of: removing unreacted silica which is carried out using 0.1% to 10% (v/v) hydrofluoric acid after performing step (b).

15 . A negative electrode for a lithium secondary battery comprising the sulfur-doped silicon negative electrode material of claim 1 .

16 . A lithium secondary battery comprising the negative electrode for the lithium secondary battery of claim 15 .

Assignees

• Lg Chemical Ltd
• Postech Res & Business Dev Found

Inventors

• Kim Jangbae
• Park Soojin
• Ryu Jaegeon
• Chae Jonghyun
• Yang Jihye

Classifications

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• C01P2006/40

  Electric properties · CPC title

• H01M10/052

  Li-accumulators · CPC title