Method of manufacturing negative electrode for secondary battery

Patent metadata

Field	Value
Publication number	US-12015143-B2
Application number	US-202017292544-A
Country	US
Kind code	B2
Filing date	Jan 16, 2020
Priority date	Jan 18, 2019
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

A method of manufacturing a negative electrode for a secondary battery. The method includes forming a first negative electrode active material layer including a carbon-based active material on at least one surface of a negative electrode current collector; and forming a second negative electrode active material layer including a silicon-based active material on a surface of the first negative electrode active material opposite the negative electrode current collector, wherein the silicon-based material is intercalated with lithium by pre-lithiation on the first negative electrode active material layer.

First claim

The invention claimed is:

1. A method of manufacturing a negative electrode for a secondary battery, comprising:
pre-lithiating a silicon-based active material to obtain a pre-lithiated silicon-based active material having lithium intercalated into the silicon-based active material, wherein the pre-lithiating is performed by placing a mesh-type copper electrode and a glassy carbon electrode into a pre-lithiation solution, wherein the pre-lithiation solution comprises a lithium salt and an organic solvent;
adding the silicon-based active material to the pre-lithiation solution containing the mesh-type copper electrode and the glassy carbon electrode; and
intercalating lithium into the silicon-based active material by performing an oxidation/reduction reaction in the pre-lithiation solution;
forming a first negative electrode active material layer comprising a carbon-based active material on at least one surface of a negative electrode current collector; and
forming a second negative electrode active material layer comprising the pre-lithiated silicon-based active material on a surface of the first negative electrode active material layer opposite the negative electrode current collector.

2. The method of claim 1 , wherein the oxidation/reduction reaction is performed by applying a current to the mesh-type copper electrode and the glassy carbon electrode at a rate of 0.001 C to 5 C.

3. The method of claim 1 , wherein the oxidation/reduction reaction is performed at 5° C. to 40° C.

4. The method of claim 1 , wherein the carbon-based active material comprises at least one selected from the group consisting of artificial graphite, natural graphite, hard carbon, soft carbon, carbon black, acetylene black, Ketjen black, graphene, and fibrous carbon.

5. The method of claim 1 , wherein the carbon-based active material has an average particle diameter (D 50 ) of 5 μm to 35 μm.

6. The method of claim 1 , wherein the silicon-based active material comprises a compound represented by the following Formula 1:
SiO x (0 ≤x< 2)  [Formula 1].

7. The method of claim 1 , wherein the silicon-based active material has an average particle diameter (D 50 ) of 5 μm to 35 μm.

8. The method of claim 1 , wherein a weight ratio of the carbon-based active material present in the first negative electrode active material layer to the silicon-based active material present in the second negative electrode active material layer is in a range of 45:65 to 95:5.

9. The method of claim 1 , wherein a ratio of a thickness of the second negative electrode active material layer to a thickness of the first negative electrode active material layer is in a range of 0.15 to 1.10.

10. The method of claim 1 , wherein the first negative electrode active material layer further comprises a first binder, and
the second negative electrode active material layer further comprises a second binder.

11. The method of claim 10 , wherein a weight ratio of the first binder present in the first negative electrode active material layer to the second binder present in the second negative electrode active material layer is in a range of 30:70 to 85:15.

Assignees

• Lg Energy Solution Ltd

Inventors

• Kim Ye Ri
• Woo Sang Wook
• Chae Oh Byong

Classifications

• H01M2004/027

  Negative electrodes · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/587 Primary

  for inserting or intercalating light metals · CPC title

• H01M4/483

  for non-aqueous cells (H01M4/485 takes precedence) · CPC title

• H01M4/366

  as layered products · CPC title