# US 2021/0280868 A1 · Negative active material for rechargeable lithium battery and rechargeable lithium battery including same

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- Number: US 2021/0280868 A1
- Document ID: US20210280868A1
- Status: Published application
- Kind: A1
- Application number: 17/190,863
- Filed: 2021-03-03
- Published: 2021-09-09
- Earliest claimed: 2020-03-03
- Assignees: Samsung SDI Co., Ltd.
- Applicants: Samsung SDI Co., Ltd.
- Inventors: Sunil PARK; Narae KIM; Jaehou NAH; Joongho MOON; Hyun SOH; Eunjoo LEE
- Web page: https://patentgrep.com/patent/US20210280868A1

## CPC

- H01M 4/366: {as layered products}
- H01M 4/583: Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/043: {involving compressing or compaction}
- H01M 4/0471: {involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis}
- H01M 4/133: Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/1393: of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/587: for inserting or intercalating light metals
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/44: Methods for charging or discharging (circuits for charging H02J7/00)
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- H01M 2004/027: {Negative electrodes}
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A negative active material for a rechargeable lithium battery includes a secondary particle in which a plurality of natural graphite primary particles are agglomerated, the plurality of primary particles including natural graphite, and the secondary particle including pores, and an amorphous carbon positioned in the pores, wherein an area of the amorphous carbon is about 10% to about 30% based on a total area of 100% of the negative active material, in a cross-section of the negative active material.

## Claims

### Claim 1

A negative active material for a rechargeable lithium battery, the negative active material comprising:
a secondary particle in which a plurality of primary particles are agglomerated, the plurality of primary particles comprising natural graphite, and the secondary particle comprising pores; and
an amorphous carbon in the pores,
wherein an area of the amorphous carbon is about 10% to about 30% based on a total area of 100% of the negative active material, in a cross-section of the negative active material.

### Claim 2 (depends on 1)

The negative active material of claim 1, wherein each primary particle of the plurality of primary particles has a particle diameter of about 5 μm to about 15 μm.

### Claim 3 (depends on 1)

The negative active material of claim 1, wherein the secondary particle has a particle diameter of about 8 μm to about 24 μm.

### Claim 4 (depends on 1)

The negative active material of claim 1, wherein the natural graphite is flake graphite.

### Claim 5 (depends on 1)

The negative active material of claim 1, wherein the natural graphite is flake graphite having a long axis and a short axis, and a length of the long axis is about 5 μm to about 15 μm.

### Claim 6 (depends on 1)

The negative active material of claim 1, wherein the secondary particle further comprises the amorphous carbon on a surface of the secondary particle.

### Claim 7 (depends on 1)

The negative active material of claim 1, wherein the negative active material comprises the amorphous carbon at an amount of about 1 wt % to about 9 wt % based on a total weight of 100 wt % of the negative active material.

### Claim 8

A method of preparing a negative active material, the method comprising:
mixing an amorphous carbon precursor with a secondary particle to prepare a mixture, the secondary particle comprising agglomerated natural graphite primary particles and comprising pores;
controlling a pressure of the mixture;
maintaining the resulting product at a temperature at which a viscosity of the amorphous carbon precursor is about 100 cP to about 1000 cP;
disintegrating the obtained material; and
heat-treating the resulting material.

### Claim 9 (depends on 8)

The method of claim 8, wherein the amorphous carbon precursor has a softening point of about 200° C. to about 300° C.

### Claim 10 (depends on 8)

The method of claim 8, wherein the temperature at which the viscosity of the amorphous carbon precursor is about 100 cP to about 1000 cP is about 350° C. to about 400° C.

### Claim 11 (depends on 8)

The method of claim 8, wherein the heat-treating is performed at about 950° C. to about 1400° C.

### Claim 12 (depends on 8)

The method of claim 8, wherein the controlling the pressure of the mixture utilizes a pressing procedure by exerting a pressure of about 10 MPa to about 100 MPa, or a decompressing procedure by reducing a pressure with a pressure of about −0.1 MPa to about −1.0 MPa.

### Claim 13 (depends on 8)

The method of claim 8, wherein the controlling the pressure of the mixture utilizes a pressing procedure by exerting a pressure.

### Claim 14 (depends on 8)

The method of claim 8, further comprising sieving the resulting product after the controlling the pressure, and before the maintaining the temperature.

### Claim 15 (depends on 1)

A rechargeable lithium battery, comprising:
a negative electrode comprising the negative active material of claim 1;
a positive electrode comprising a positive active material; and
an electrolyte between the negative electrode and the positive electrode.