Negative electrode slurry composition for lithium secondary battery, and method for preparing the same

Patent metadata

Field	Value
Publication number	US-2020259162-A1
Application number	US-201816761639-A
Country	US
Kind code	A1
Filing date	Nov 6, 2018
Priority date	Nov 6, 2017
Publication date	Aug 13, 2020
Grant date	—

Abstract

A negative electrode slurry composition including (1) clay particles having, a plate-type structure and an average particle diameter (D 50 ) of 10 nm to 2 μm, (2) carboxymethylcellulose (CMC), (3) a negative electrode active material, and (4) an aqueous solvent, wherein a weight ratio of the carboxymethylcellulose and the clay particles is 9.5:0.5 to 4:6. The negative electrode slurry composition is capable of solving problems due to the deterioration of storage stability and dispersibility of solids in a negative electrode slurry composition haying a high solid content.

First claim

1 . A negative electrode slurry composition comprising:
(1) clay particles having a plate-type structure and an average particle diameter (D 50 ) of 10 nm to 2 μm; (2) carboxymethylcellulose (CMC); (3) a negative electrode active material; and (4) an aqueous solvent, wherein weight ratio of the carboxymethylcellulose and the clay particles is 9.5:0.5 to 4 6.

2 . The negative electrode slurry composition of claim 1 , wherein at the surface of the clay, an edge portion of the plate represents a partially positive charge (δ + ) and an inner surface portion of the edge of the plate represents a partially negative charge (δ − ), and
the positive charge of the edge portion of clay particles interacts with a carboxy group of the carboxymethyicellulose through a polar interaction,

3 . The negative electrode slurry composition of claim 1 , wherein the clay particles contain a 2:1 type clay mineral having a ratio of a tetrahedral sheet and an octahedral sheet of 2:1.

4 . The negative electrode slurry composition of claim 1 , wherein the clay particles comprise one or more selected from the group consisting of hectorite, saponite, and bentonite,

5 . The negative electrode slurry composition of claim I, wherein the negative electrode slurry composition has a sedimentation height of 10 mm or less, when a sedimentation height is measured by filling the negative electrode slurry composition to a height of 135 mm in a glass cylinder having an inner diameter of 8 mm, and then 24 hours later, allowing the negative electrode slurry composition to sink downwards from the height of 135 mm.

6 . The negative electrode slurry composition of claim wherein the negative electrode slurry composition has an intensity of force acting at a height of 10 mm from a bottom of 1 N or less, when the intensity of force is measured by filling the negative electrode slurry composition to a height of 50 mm in a glass cylinder having an inner diameter of 25 mm, and then 24 hours later, moving a rectangular stick having a thickness of 5 mm in all directions from top to bottom at a speed of 1 mm/s.

7 . The negative electrode slurry composition of claim 1 , wherein the negative electrode slurry composition has a shear thickening slope value of 0,3 or less when measuring a shear viscosity.

8 . The negative electrode slurry composition of claim 1 , wherein the negative electrode slurry composition is capable of passing through a filter of 100 mesh or more.

9 . The negative electrode slurry composition of claim wherein the negative electrode slurry composition has a viscosity of 8,000 cp or less

10 . The negative electrode slurry composition of claim 1 , wherein the negative electrode slurry composition has a phase angle of 25° or higher.

11 . The negative electrode slurry composition of claim 1 , wherein the negative electrode slurry composition has a solid content of 45 wt % or greater.

12 . A method of preparing the negative electrode slurry composition of claim 1 , the method comprising:
(A) preparing a first mixture comprising clay particles having a plate-type structure and an average particle diameter (D 50 ) of 10 nm to 2 82 m, carboxymethylcellulose (CMC), and the aqueous solvent; (B) preparing a second mixture by adding thee negative electrode active material to the first mixture; and (C) preparing thee negative electrode slurry composition by adding a binder o the second mixture, wherein the weight ratio of the carboxymethylcellulose and the clay particles is 9.5:0.5 to 4:6.

13 . The method of claim 12 , further comprising (1-1) mixing a conductive agent with the first mixture after (A) of preparing the first mixture and before (B).

14 . The method of claim 12 , further comprising (B-1) introducing clay particles having a plate-type structure and an average diameter (D50) of 10 nm to 2 μm, carboxymethylcellulose (CIVIC), and an aqueous solvent to the second mixture between (B) and (C), wherein the weight ratio of the carboxymethylcellulose and the clay particles is 9:1 to 5:5.

15 . The method of claim 14 , wherein the negative electrode slurry composition has a solid content of 45 wt % or greater,

16 . A negative electrode for a lithium secondary battery manufactured by using the negative electrode slurry composition according to claim 1 .

17 . A lithium secondary battery comprising the negative electrode of claim 16 .

Assignees

• Lg Chemical Ltd

Inventors

• Lee Jong Won
• Yoo Houng Sik
• Choi Hyeon

Classifications

• H01M4/13 Primary

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/139

  Processes of manufacture · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/622

  being polymers · CPC title