Negative active material for rechargeable lithium battery and rechargeable lithium battery comprising same

Patent metadata

Field	Value
Publication number	US-2024332512-A1
Application number	US-202418739412-A
Country	US
Kind code	A1
Filing date	Jun 11, 2024
Priority date	Nov 7, 2019
Publication date	Oct 3, 2024
Grant date	—

Abstract

A negative active material for a rechargeable lithium battery and a rechargeable lithium battery, the negative active material including secondary particles of agglomerated primary particles, the primary particles including Si particles with SiC on a surface of the Si particles; and an amorphous carbon surrounding the secondary particles, wherein a peak intensity ratio (I Si(111) /I SiC(111) ) of a peak intensity (I Si(111) ) at a Si (111) plane relative to a peak intensity (I SiC(111) ) at a SiC (111) plane is about 5 to about 50 measured by X-ray diffraction analysis using a CuKα ray.

First claim

What is claimed is:

1 . A negative active material for a rechargeable lithium battery, the negative active material comprising:
a first negative active material; and a second negative active material, wherein: the first negative active material and the second negative active material are included at a mixing ratio of about 1:30 to about 1:4 by weight, the first negative active material comprises secondary particles of agglomerated primary particles, the primary particles including Si particles with SiC on a surface of the Si particles; and an amorphous carbon surrounding the secondary particles, the Si particles have an aspect ratio of about 5 to about 20, the first negative active material has a full width at half maximum, FWHM (111), of a diffraction peak at a (111) plane found by X-ray diffraction of the Si particles using a CuKα ray of about 0.5 degrees (°) to about 7 degrees (°), and the second negative active material comprises crystallin carbon.

2 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the crystalline carbon comprises graphite.

3 . The negative active material for a rechargeable lithium battery as claimed in claim 2 , wherein the graphite comprises an unspecified shaped, sheet-shaped, flake-shaped, spherical-shaped, or fiber-shaped natural graphite, or artificial graphite.

4 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the first negative active material has a peak intensity ratio (I Si(111) /I SiC(111 ) of a peak intensity (I Si(111) ) at a Si(111) plane relative to a peak intensity (I SiC(111 ) at a SiC (111) plane of about 5 to about 50 measured by X-ray diffraction analysis using a CuKα ray.

5 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the amorphous carbon fills pores between the primary particles.

6 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein:
the SiC is continuously on the surface of the Si particles in a form of a layer, or the SiC is discontinuously on the surface of the Si particles in a form of an island or a dot.

7 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein a thickness of the SiC on the surface of the Si is about 5 nm or less.

8 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein a thickness of the SiC on the surface of the Si is about 2 nm to about 5 nm or less.

9 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the particle diameter of the SiC is about 3 nm to about 5 nm.

10 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the Si particles are of a flake type.

11 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the Si particles have a particle diameter of about 10 nm to 200 nm.

12 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the first negative active material includes the Si in an amount of about 40 wt % to about 70 wt %, based on a total weight of the first negative active material.

13 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein a thickness of the amorphous carbon is about 5 nm to about 50 nm.

14 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the first negative active material includes the amorphous carbon in an amount of about 20 wt % to about 50 wt %, based on a total weight of the first negative active material.

15 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein a particle diameter of the secondary particles is about 3 μm to about 20 μm.

16 . A rechargeable lithium battery, comprising:
a negative electrode including the negative active material as claimed in claim 1 ; a positive electrode; and an electrolyte.

17 . The rechargeable lithium battery as claimed in claim 9 , wherein a peak intensity ratio (I Gri(002) /I SiC(111) ) of a peak intensity (I Gr(002) ) at a crystalline carbon (002) plane relative to a peak intensity (I SiC(111) ) at a SiC (111) plane, measured by X-ray diffraction analysis using a CuKα ray, is about 150 to about 1,500 in the negative electrode.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Lee Dae-Hyeok
• Kim Young-Min
• Kim Jaemyung
• Nah Jaehou
• Shin Changsu
• Won Jongmin

Classifications

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M10/0525

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

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/364

  as mixtures · CPC title