Negative active material and rechargeable lithium battery including same

Patent metadata

Field	Value
Publication number	US-12542272-B2
Application number	US-202217939142-A
Country	US
Kind code	B2
Filing date	Sep 7, 2022
Priority date	Sep 9, 2021
Publication date	Feb 3, 2026
Grant date	Feb 3, 2026

Abstract

A negative active material for a rechargeable lithium battery and a rechargeable lithium battery, the negative active material includes a porous silicon-carbon composite that includes silicon, carbon, and magnesium silicate (MgSiO3), wherein the negative active material has a diffraction peak intensity ratio IMgSiO3(610)/ISi(111) of 0.001<IMgSiO3(610)/ISi(111)<0.01, which is a ratio of a diffraction peak intensity IMgSiO3(610) by MgSiO3 at 2θ=30° to 32° to a diffraction peak intensity ISi(111) by Si(111) detected at 2θ=27.5° to 29.5° in a X-ray diffraction analysis.

First claim

What is claimed is:

1 . A negative active material for a rechargeable lithium battery, the active material comprising a porous silicon-carbon composite that includes silicon, carbon, and magnesium silicate (MgSiO 3 ),
wherein the negative active material has a diffraction peak intensity ratio I MgSiO3(610) /I Si(111) of 0.001<I MgSiO3(610) /I Si(111) <0.01, which is a ratio of a diffraction peak intensity I MgSiO3(610) by MgSiO 3 at 2θ=30° to 32° to a diffraction peak intensity I Si (111) by Si(111) detected at 2θ=27.5° to 29.5° in a X-ray diffraction analysis.

2 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the magnesium silicate is included in the negative active material in an amount of 0.01 wt % to 1.0 wt %, based on a total weight of the negative active material.

3 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the magnesium silicate is included in the negative active material in an amount of 0.01 wt % to 0.6 wt %, based on a total weight of the negative active material.

4 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the carbon includes amorphous carbon.

5 . The negative active material for a rechargeable lithium battery as claimed in claim 4 , wherein the amorphous carbon includes soft carbon, hard carbon, or a combination thereof.

6 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the carbon is included in the negative active material in an amount of 5 wt % to 45 wt %, based on a total weight of the negative active material.

7 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein:
the porous silicon-carbon composite includes pores, and the carbon covers an exterior wall of the pores, the silicon, and the magnesium silicate.

8 . The negative active material for a rechargeable lithium battery as claimed in claim 7 , wherein the pores have an average size of 50 nm or more.

9 . The negative active material for a rechargeable lithium battery as claimed in claim 8 , wherein the pores have an average size of 50 nm to 500 nm.

10 . The negative active material for a rechargeable lithium battery as claimed in claim 1 , wherein the negative active material is prepared by:
primary heat-treating magnesium silicide to prepare a heated product, etching the heated product to prepare a porous silicon, mixing the porous silicon with an amorphous carbon precursor to prepare a mixture, and secondary heat-treating the mixture.

11 . The negative active material for a rechargeable lithium battery as claimed in claim 10 , wherein the primary heat treatment is performed under an air atmosphere.

12 . The negative active material for a rechargeable lithium battery as claimed in claim 10 , wherein the primary heat treatment is performed at 600° C. to 700° C. for 5 hours to 30 hours.

13 . The negative active material for a rechargeable lithium battery as claimed in claim 10 , wherein the etching is performed using an acid.

14 . The negative active material for a rechargeable lithium battery as claimed in claim 13 , wherein the acid is hydrochloric acid.

15 . The negative active material for a rechargeable lithium battery as claimed in claim 10 , wherein a mixing ratio of the porous silicon and the amorphous carbon precursor is 95:5 to 55:45 by weight.

16 . The negative active material for a rechargeable lithium battery as claimed in claim 10 , wherein the secondary heat treatment is performed at 800° C. to 1,200° C.

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

18 . The rechargeable lithium battery as claimed in claim 17 , wherein the negative electrode includes:
the negative active material as a first negative active material, and crystalline carbon as a second negative active material.

19 . The rechargeable lithium battery as claimed in claim 18 , wherein a mixing ratio of the first negative active material and the second negative active material is 1:99 to 40:60 by weight.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Lee Eunjoo
• Kim Yongseok
• Kim Jaewon
• Nah Jaehou
• Sheem Kyeu Yoon

Classifications

• H01M2004/027

  Negative electrodes · CPC title

• H01M2004/021

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

• H01M10/0525

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

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title