Positive Electrode and Secondary Battery Including Same

Patent metadata

Field	Value
Publication number	US-2025038185-A1
Application number	US-202418594948-A
Country	US
Kind code	A1
Filing date	Mar 4, 2024
Priority date	Feb 7, 2018
Publication date	Jan 30, 2025
Grant date	—

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

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 comprises a positive electrode active material, a binder, and a conductive material, wherein the conductive material comprises multi-walled carbon nanotubes having a length of 0.5 μm to 3 μm with an average length of 1 μm to 2 μm and a length standard deviation at 0.5 μm or less, wherein no multi-walled carbon nanotube having a length exceeding 3 μm is included in the positive electrode active material layer, wherein the positive electrode active material layer contains the multi-walled carbon nanotubes in an amount from 0.1 wt. % to 1 wt. % with respect to a total weight of the positive electrode active material layer.

2 . The positive electrode of claim 1 , wherein substantially all of the multi-walled carbon nanotubes in the positive electrode active material layer have the length of 0.5 μm to 3 μm with an average length of 1 μm to 2 μm and a length standard deviation at 0.5 μm or less.

3 . The positive electrode of claim 1 , wherein the conductive material consists essentially of the multi-walled carbon nanotubes having the length of 0.5 μm to 3 μm with an average length of 1 μm to 2 μm and a length standard deviation at 0.5 μm or less.

4 . The positive electrode of claim 1 , wherein the length of the multi-walled carbon nanotubes observable in the positive electrode active material layer is between 0.5 μm and 3 μm.

5 . The positive electrode of claim 1 , wherein the length of the multi-walled carbon nanotubes observable in the positive electrode active material layer is under 2.5 μm.

6 . The positive electrode of claim 1 , wherein the multi-walled carbon nanotubes observed in the positive electrode active material layer have the length of 0.5 μm to 3 μm with an average length of 1 μm to 2 μm and a length standard deviation at 0.5 μm or less.

7 . The positive electrode of claim 1 , wherein the average length of the multi-walled carbon nanotubes observed in the positive electrode active material layer is from 1 μm to 1.4 μm.

8 . The positive electrode of claim 1 , wherein the length standard deviation of the multi-walled carbon nanotubes observable in the positive electrode active material layer is from 0.3 μm to 0.5 μm.

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

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

11 . 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.

12 . A method of making a positive electrode, the method comprising:
providing a positive electrode slurry comprising a positive electrode active material, a conductive material, a dispersant, a binder, and a solvent; applying the positive electrode slurry onto a current collector; subsequently drying the positive electrode slurry on the current collector to evaporate the solvent and to provide a positive electrode active material layer on the current collector, wherein the conductive material comprises multi-walled carbon nanotubes having a length of 0.5 μm to 3 μm with an average length of 1 μm to 2 μm and a length standard deviation at 0.5 μm or less, wherein no multi-walled carbon nanotube having a length exceeding 3 μm is included in the positive electrode active material layer, wherein the positive electrode active material layer contains the multi-walled carbon nanotubes in an amount from 0.1 wt. % to 1 wt. % with respect to a total weight of the positive electrode active material layer.

13 . The method of claim 12 , wherein substantially all of the multi-walled carbon nanotubes in the positive electrode active material layer have the length of 0.5 μm to 3 μm with an average length of 1 μm to 2 μm and a length standard deviation at 0.5 μm or less.

14 . The method of claim 12 , wherein the conductive material consists essentially of the multi-walled carbon nanotubes having the length of 0.5 μm to 3 μm with an average length of 1 μm to 2 μm and a length standard deviation at 0.5 μm or less.

15 . The method of claim 12 , wherein the length of the multi-walled carbon nanotubes observable in the positive electrode active material layer is between 0.5 μm and 3 μm.

16 . The method of claim 12 , wherein the length of the multi-walled carbon nanotubes observable in the positive electrode active material layer is under 2.5 μm.

17 . The method of claim 12 , wherein the multi-walled carbon nanotubes observed in the positive electrode active material layer have the length of 0.5 μm to 3 μm with an average length of 1 μm to 2 μm and a length standard deviation at 0.5 μm or less.

18 . The method of claim 12 , wherein the average length of the multi-walled carbon nanotubes contained in the positive electrode slurry is from 1 μm to 1.4 μm.

19 . The method of claim 12 , wherein the length standard deviation of the multi-walled carbon nanotubes contained in the positive electrode slurry is from 0.3 μm to 0.5 μm.

20 . The method of claim 12 , wherein the positive electrode slurry contains the multi-walled carbon nanotubes in an amount from 0.2 to 0.7 wt. % with respect to the total weight of the positive electrode slurry excluding the solvent.

21 . The method of claim 12 , wherein providing the positive electrode slurry comprises:
providing a mixture comprising bundle-type multi-walled carbon nanotubes and the dispersant; and processing the mixture to unbundle at least part of the bundle-type multi-walled carbon nanotubes to provide the multi-walled carbon nanotubes having a length between 0.5 μm and 3 μm with an average length from 1 μm to 2 μm and a length standard deviation at 0.5 μm or less.

22 . The method of claim 21 , wherein processing the mixture comprises providing the positive electrode slurry comprises milling the mixture.

Assignees

• 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