Negative electrode for lithium secondary battery and lithium secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-2022209217-A1
Application number	US-202017605057-A
Country	US
Kind code	A1
Filing date	Apr 16, 2020
Priority date	Apr 24, 2019
Publication date	Jun 30, 2022
Grant date	—

Abstract

The present invention relates a negative electrode for a lithium secondary battery, and a lithium secondary battery comprising same, wherein the negative electrode for a lithium secondary battery comprises a current collector, and a negative electrode active material layer including a first layer formed on the current collector and a second layer formed on the first layer, the first layer containing a first carbon-based negative electrode active material, and the second layer containing a second carbon-based negative electrode active material, wherein the degree of divergence (DD) value of the first layer is 30-90% of the DD value of the negative electrode active material layer, the DD value is defined by formula 1 below.DD (Degree of Divergence)=(Ia/Itotal)*100  [Formula 1](In formula 1, Ia is the sum of peak intensities of peaks at out-of plane angles as measured by XRD with CuKα, and Itotal is the sum of peak intensities of peaks at all angles as measured by XRD with CuKα).

First claim

1 . A negative electrode for a lithium secondary battery, the negative electrode comprising:
a current collector; and a negative electrode active material layer including: a first layer formed on both sides of the current collector and comprising a first carbon-based negative electrode active material, and a second layer formed on the first layer and comprising a second carbon-based negative electrode active material, wherein: a DD (Degree of Divergence) value of the first layer is 30% to 90% of a DD value of the negative electrode active material layer and, the DD value is defined by Equation 1:
DD (Degree of Divergence)=( I a /I total )*100  [Equation 1]

In Equation 1, I a is a sum of peak intensities at non-planar angles measured by XRD using a CuKα ray, and I total is a sum of peak intensities at all angles measured by XRD using a CuKα ray.

2 . The negative electrode for the lithium secondary battery of claim 1 , wherein the DD value of the first layer is 70% to 90% of the DD value of the negative electrode active material layer.

3 . The negative electrode for the lithium secondary battery of claim 1 , wherein a total thickness of the first layer disposed on the both sides is 80 μm to 800 μm.

4 . The negative electrode for the lithium secondary battery of claim 1 , wherein a total thickness of the second layer disposed on the both sides is 20 μm to 200 μm.

5 . The negative electrode for the lithium secondary battery of claim 1 , wherein a total thickness of the negative electrode active material layer disposed on the both sides is 100 μm to 1000 μm.

6 . The negative electrode for the lithium secondary battery of claim 1 , wherein a total thickness of the first layer disposed on the both sides is 80% or less of a total thickness of the negative electrode active material layer disposed on the both sides.

7 . The negative electrode for the lithium secondary battery of claim 1 , wherein the DD value of the negative electrode active material layer is 19 to 60.

8 . The negative electrode for the lithium secondary battery of claim 1 , wherein the DD value of the first layer is 18 to 54.

9 . The negative electrode for the lithium secondary battery of claim 1 , wherein:
the I a is a sum of peak intensities at 2η=42.4±0.2°, 43.4±0.2°, 44.6±0.2°, and 77.5±0.2° measured by XRD using a CuKα ray, and the I total is a sum of peak intensities at 2η=26.5±0.2°, 42.4±0.2°, 43.4±0.2°, 44.6±0.2°, 54.7±0.2°, and 77.5±0.2° measured by XRD using a CuKα ray.

10 . The negative electrode for the lithium secondary battery of claim 1 , wherein the peak intensities are a peak integral area values.

11 . The negative electrode for the lithium secondary battery of claim 1 , wherein the first carbon-based negative electrode active material or the second carbon-based negative electrode active material is artificial graphite or a mixture of artificial graphite and natural graphite.

12 . The negative electrode for the lithium secondary battery of claim 1 , wherein the first layer or the second layer further includes a Si-based negative electrode active material, a Sn-based negative electrode active material, a lithium vanadium oxide, or a combination thereof.

13 . A lithium secondary battery, comprising:
the negative electrode of claim 1 ; a positive electrode; and an electrolyte.

14 . The lithium secondary battery of claim 13 , wherein the lithium secondary battery is a high-power battery.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Lee Jinhyon
• Kim Hongjeong
• Eom Hyeri
• Lee Sangjun
• Lim Daeseop

Classifications

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/587 Primary

  for inserting or intercalating light metals · CPC title

• H01M4/133 Primary

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• H01M2004/027

  Negative electrodes · CPC title