# US 2023/0054932 A1 · Negative electrode active material, negative electrode including same, secondary battery including same and method for preparing negative electrode active material

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- Number: US 2023/0054932 A1
- Document ID: US20230054932A1
- Status: Published application
- Kind: A1
- Application number: 17/886,142
- Filed: 2022-08-11
- Published: 2023-02-23
- Earliest claimed: 2021-08-13
- Assignees: LG Energy Solution, Ltd.
- Applicants: LG Energy Solution, LTD.
- Inventors: Junghyun CHOI; Su Min LEE; Sun Young SHIN; Yong Ju LEE
- Web page: https://patentgrep.com/patent/US20230054932A1

## CPC

- C01B 33/24: Alkaline-earth metal silicates
- C01B 33/32: Alkali metal silicates ({C01B33/24} , C01B33/26 take precedence)
- H01M 4/362: {Composites}
- H01M 4/48: of inorganic oxides or hydroxides
- H01M 10/052: Li-accumulators
- C01P 2002/86: by NMR- or ESR-data
- C01P 2006/40: Electric properties
- H01M 2004/027: {Negative electrodes}
- Y02E 60/10: Energy storage using batteries
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A negative electrode active material, a negative electrode including the same, a secondary battery including the same and a method for preparing a negative electrode active material.

## Claims

### Claim 1

A negative electrode active material, comprising:
particles comprising a silicon-containing oxide represented by SiOx, wherein 0<x<2; and
lithium distributed in the particles,
wherein the lithium is present in a form of (a) crystalline Li2Si2O5, and optionally one or more selected from (b) crystalline Li2SiO3, (c) crystalline Li4SiO4 or (d) amorphous lithium silicate,
a content of the crystalline Li2Si2O5 is higher than the sum of a content of the crystalline Li2SiO3 and a content of the crystalline Li4SiO4, and
a total content of the crystalline phase present in the particles is higher than a total content of the amorphous phase.

### Claim 2 (depends on 1)

The negative electrode active material of claim 1,
wherein the lithium is present in the form of (a) crystalline Li2Si2O5, (b) crystalline Li2SiO3, and optionally one or more selected from (c) crystalline Li4SiO4 or (d) amorphous lithium silicate.

### Claim 3 (depends on 1)

The negative electrode active material of claim 1, wherein the total content of the crystalline phase present in the particles is more than 50 parts by weight and 80 parts by weight or less based on total 100 parts by weight of the particles.

### Claim 4 (depends on 1)

The negative electrode active material of claim 1, wherein a difference between the content of the crystalline Li2Si2O5 and the content of the crystalline Li2SiO3 is 1 part by weight to 40 parts by weight based on total 100 parts by weight of the particles.

### Claim 5 (depends on 1)

The negative electrode active material of claim 1, wherein the negative electrode active material does not comprise the crystalline Li4SiO4.

### Claim 6 (depends on 1)

The negative electrode active material of claim 1, wherein during 29Si-MAS-NMR analysis of the negative electrode active material, a height of a peak p1 of Li2SiO3 that appears at a chemical shift peak of −70 ppm to −80 ppm is smaller than a height of a peak p2 of Li2Si2O5 that appears at a chemical shift peak of −90 ppm to −100 ppm.

### Claim 7 (depends on 1)

The negative electrode active material of claim 1, wherein during 29Si-MAS-NMR analysis of the negative electrode active material, a ratio p2/p1 of a height of a peak p2 of Li2Si2O5 that appears at a chemical shift peak of −90 ppm to −100 ppm to a height of a peak p1 of Li2SiO3 that appears at a chemical shift peak of −70 ppm to −80 ppm is more than 0.1 and 6.5 or less.

### Claim 8 (depends on 1)

The negative electrode active material of claim 1, wherein a peak p3 of Li4SiO4 that appears at a chemical shift peak of −60 ppm to −69 ppm is not present during 29Si-MAS-NMR analysis of the negative electrode active material.

### Claim 9 (depends on 1)

The negative electrode active material of claim 1, wherein the negative electrode active material comprises the crystalline SiO2 in an amount of less than 5 parts by weight based on total 100 parts by weight of the particles.

### Claim 10 (depends on 1)

The negative electrode active material of claim 1, wherein the lithium is present in an amount of 0.5 part by weight to 25 parts by weight based on total 100 parts by weight of the negative electrode active material.

### Claim 11 (depends on 1)

The negative electrode active material of claim 1, wherein a negative electrode active material obtained by adding 0.5 g of the negative electrode active material to 50 mL of distilled water and stirring the resulting mixture for 3 hours has a pH of 9 or more and 13 or less at 23° C.

### Claim 12 (depends on 1)

The negative electrode active material of claim 1, further comprising a carbon layer disposed on the respective particles.

### Claim 13 (depends on 1)

A method for preparing the negative electrode active material of claim 1, the method comprising:
preparing a composition for forming a negative electrode active material by mixing particles comprising a silicon-containing oxide represented by SiOx, wherein 0<x<2, with a lithium precursor; and
heat-treating the composition for forming the negative electrode active material at a temperature in a range of 780° C. to 900° C.

### Claim 14 (depends on 13)

The method of claim 13, further comprising:
performing an acid treatment on the heat-treated composition for forming the negative electrode active material.

### Claim 15 (depends on 13)

The method of claim 13, further comprising:
forming a carbon layer on the particles comprising the silicon-containing oxide before mixing the particles comprising the silicon-containing oxide with the lithium precursor.

### Claim 16 (depends on 13)

The method of claim 13, wherein the heat treatment is performed for a time in a range of 1 hour to 12 hours.

### Claim 17 (depends on 13)

The method of claim 13, wherein the heat treatment is performed in an inert atmosphere.

### Claim 18 (depends on 1)

A negative electrode comprising:
a negative electrode current collector; and
a negative electrode active material layer disposed on at least one surface of the negative electrode current collector,
wherein the negative electrode active material layer comprises a negative electrode material comprising the negative electrode active material of claim 1.

### Claim 19 (depends on 18)

A secondary battery comprising:
the negative electrode of claim 18;
a positive electrode facing the negative electrode;
a separator interposed between the negative electrode and the positive electrode; and
an electrolyte.