Positive electrode and secondary battery including same

Patent metadata

Field	Value
Publication number	US-11929496-B2
Application number	US-201916958925-A
Country	US
Kind code	B2
Filing date	Feb 1, 2019
Priority date	Feb 7, 2018
Publication date	Mar 12, 2024
Grant date	Mar 12, 2024

Abstract

A positive electrode and a secondary battery including the same are provided. The positive electrode includes a current collector and a positive electrode active material layer disposed on the current collector, wherein the positive active material layer includes a positive electrode active material, a binder, and a multi-walled carbon nanotube, wherein the multi-walled carbon nanotube has an average length of 1-2 μm and has a length standard deviation of 0.5 μm or less.

First claim

The invention claimed is:

1. A positive electrode comprising:
a current collector; and
a positive electrode active material layer disposed on the current collector,
wherein the positive electrode active material layer includes a positive electrode active material, a binder, and-a multi-walled carbon nanotubes,
wherein the multi-walled carbon nanotubes have an average length of 1 to −2 μm and have a length standard deviation of 0.5 μm or less,
wherein lengths of all of the multi-walled carbon nanotubes are from 0.5 to −3.0 μm, and
wherein the multi-walled carbon nanotubes are contained in an amount of 0.1 to 1 wt % with respect to a total weight of the positive electrode active material layer.

2. The positive electrode of claim 1 ,
wherein the multi-walled carbon nanotubes are contained in an amount of 0.2 to 0.7 wt % with respect to a total weight of the positive electrode active material layer.

3. The positive electrode of claim 1 ,
wherein the positive electrode active material is contained in an amount of 96 to 99 wt % with respect to a total weight of the positive electrode active material layer.

4. The positive electrode of claim 1 ,
wherein a loading amount of the positive electrode active material layer is 15 to −40 mg/cm 2 .

5. A secondary battery comprising:
the positive electrode according to claim 1 ,
a negative electrode;
a separator interposed between the positive electrode and the negative electrode; and
an electrolyte.

6. A method of preparing the positive electrode of claim 1 comprising:
preparing a conductive material dispersed solution;
forming a positive electrode slurry containing the conductive material dispersed solution, a positive electrode active material, a binder, and a solvent; and
applying and drying the positive electrode slurry on a current collector,
wherein the conductive material dispersed solution contains-a multi-walled carbon nanotubes, a dispersant, and a dispersion medium, and the multi-walled carbon nanotubes have an average length of 1 μm to 2 μm and have a length standard deviation of 0.5 μm or less.

7. The method of claim 6 , wherein the conductive material dispersed solution is prepared by mixing the multi-walled carbon nanotubes which are bundle-type multi-walled carbon nanotubes, the dispersant, and the dispersion medium to form a mixture; and controlling a particle size distribution of the bundle-type multi-walled carbon nanotubes.

8. The method of claim 7 , wherein the controlling the particle size distribution of the bundle-type multi-walled carbon nanotubes is performed by milling or ultrasonic treatment.

9. The method of claim 6 , wherein a viscosity of the conductive material dispersed solution is 10,000 to 30,000 cps at 35 to 50° C.

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Yoo Jung Woo
• Kim Ye Lin
• Kim Tae Gon

Classifications

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/1391

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/625 Primary

  Carbon or graphite · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title