# US 8,771,878 B2 · Positive electrode for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same

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- Number: US 8,771,878 B2
- Document ID: US8771878B2
- Status: Granted
- Kind: B2
- Application number: 13/472,433
- Filed: 2012-05-15
- Published: 2013-01-31
- Granted: 2014-07-08
- Earliest claimed: 2011-07-28
- Assignees: Samsung SDI Co., Ltd.
- Applicants: Da-Woon Han; Kyeu-Yoon Sheem; Eui-Hwan Song
- Inventors: Da-Woon Han; Kyeu-Yoon Sheem; Eui-Hwan Song
- Web page: https://patentgrep.com/patent/US8771878B2

## CPC

- H01M 4/622: {being polymers}
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- H01M 4/13: Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M 4/139: Processes of manufacture
- H01M 4/623: {fluorinated polymers}
- H01M 4/625: {Carbon or graphite}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A positive electrode for a rechargeable lithium battery including a current collector and a positive active material layer disposed on the current collector, a method of manufacturing the positive electrode, and a rechargeable lithium battery including the positive electrode. Here, the positive active material layer includes a positive active material and a coating layer on the surface of the positive active material, wherein the coating layer is formed of a coating layer composition including carbon nano particles, polyvinylpyrrolidone, and polyvinylidene fluoride.

## Claims

### Claim 1

A positive electrode for a rechargeable lithium battery comprising:
a current collector; and
a positive active material layer on the current collector, and
wherein the positive active material layer comprises a positive active material and a coating layer on the surface of the positive active material, and
the coating layer comprises a coating layer composition comprising carbon nano particles, polyvinylpyrrolidone, and polyvinylidene fluoride.

### Claim 2 (depends on 1)

The positive electrode of claim 1, wherein the carbon nano particles comprise carbon nanotubes and/or carbon nano fibers.

### Claim 3 (depends on 1)

The positive electrode of claim 1, wherein the positive active material layer comprises
the carbon nano particles in an amount of 0.1 to 10 wt %,
the polyvinylpyrrolidone in an amount of 0.01 to 6 wt %,
the polyvinylidene fluoride in an amount of 0.5 to 10 wt %, and
the positive active material in a remaining balance amount.

### Claim 4 (depends on 1)

The positive electrode of claim 1, wherein the polyvinylpyrrolidone and the polyvinylidene fluoride are comprised in a weight ratio of 1:1.5 to 1:9.

### Claim 5 (depends on 1)

The positive electrode of claim 1, wherein the polyvinylpyrrolidone and the polyvinylidene fluoride are comprised in weight ratio of 1:3 to 1:8.

### Claim 6 (depends on 1)

The positive electrode of claim 1, wherein the coating layer comprises the carbon nano particles each having a hydrophilic functional group on its surface.

### Claim 7 (depends on 6)

The positive electrode of claim 6, wherein the hydrophilic functional group comprises a carbonyl group, a hydroxyl group, or a combination thereof.

### Claim 8 (depends on 7)

The positive electrode of claim 7, wherein the mole ratio of the hydroxyl group to the carbonyl group is 0.5 to 1.

### Claim 9 (depends on 1)

The positive electrode of claim 1, wherein an absorbance ratio at 1667 cm−1 peak and 1397 cm−1 peak of the positive active material layer is in a range of 0.5 to 1.

### Claim 10 (depends on 1)

The positive electrode of claim 1, wherein the coating layer composition further comprises a carbon-based material.

### Claim 11 (depends on 10)

The positive electrode of claim 10, wherein the carbon-based material comprises natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, amorphous carbon powder, or a combination thereof.

### Claim 12 (depends on 10)

The positive electrode of claim 10, wherein the carbon nano particles and the carbon-based material are comprised in a weight ratio of 1:9 to 9:1.

### Claim 13 (depends on 10)

The positive electrode of claim 10, wherein the carbon-based material has a surface area in a range from 5 m2/g to 2,000 m2/g.

### Claim 14 (depends on 10)

The positive electrode of claim 10, wherein the coating layer comprises the carbon nano particles and the carbon-based material as a single layer.

### Claim 15 (depends on 10)

The positive electrode of claim 10, wherein the coating layer comprises
a first layer comprising the carbon nano particles; and
a second layer on the first layer comprising the carbon-based material, and
wherein the second layer has protrusions and depressions.

### Claim 16 (depends on 1)

The positive electrode of claim 1, wherein the positive electrode has density in a range from 3.0 g/cc to 4.0 glee.

### Claim 17 (depends on 1)

A rechargeable lithium battery comprising:
the positive electrode according to claim 1;
a negative electrode; and
an electrolyte solution impregnating the positive electrode and the negative electrode.