Method of preparing negative electrode

Patent metadata

Field	Value
Publication number	US-12567576-B2
Application number	US-202118022781-A
Country	US
Kind code	B2
Filing date	Oct 25, 2021
Priority date	Oct 26, 2020
Publication date	Mar 3, 2026
Grant date	Mar 3, 2026

Abstract

A method of preparing a negative electrode which includes preparing a negative electrode structure including expanded natural graphite, impregnating the negative electrode structure with a pre-lithiation solution to form an impregnated negative electrode structure, and pre-lithiating the impregnated negative electrode structure by electrochemically charging the impregnated negative electrode structure to 10% to 20% of charge capacity of the negative electrode structure.

First claim

The invention claimed is:

1 . A method of preparing a negative electrode, the method comprising:
preparing a negative electrode structure comprising expanded natural graphite; impregnating the negative electrode structure with a pre-lithiation solution to form an impregnated negative electrode structure; pre-lithiating the impregnated negative electrode structure by electrochemically charging the impregnated negative electrode structure to 10% to 20% of a charge capacity of the negative electrode structure, wherein the expanded natural graphite comprises oxygen in an amount ranging from 800 ppm to 3,000 ppm based on a weight of the expanded natural graphite.

2 . The method of claim 1 , wherein, in the pre-lithiating, the impregnated negative electrode structure is electrochemically charged to 13% to 16% of the charge capacity of the negative electrode structure.

3 . The method of claim 1 , wherein the electrochemical charging is performed using a lithium metal as a counter electrode, wherein the lithium metal is present in the pre-lithiation solution and is spaced apart from the impregnated negative electrode structure.

4 . The method of claim 1 , wherein the impregnation is performed for 0.5 hours to 15 hours.

5 . The method of claim 1 , wherein the pre-lithiation solution comprises a lithium salt and an organic solvent.

6 . The method of claim 1 , wherein the electrochemical charging is performed at a current density of 0.1 mA/cm 2 to 3 mA/cm 2 .

7 . The method of claim 1 , wherein an interplanar spacing d002 of a (002) plane of the expanded natural graphite during X-ray diffraction (XRD) measurement is in a range of 0.3370 nm to 0.3410 nm.

8 . The method of claim 1 , wherein a Brunauer-Emmett-Teller (BET) specific surface area of the expanded natural graphite is in a range of 4 m 2 /g to 8 m 2 /g.

9 . The method of claim 1 , wherein a crystallite size Lc of the expanded natural graphite in a c-axis direction during XRD measurement is in a range of 10 nm to 24 nm.

10 . The method of claim 1 , wherein an average particle diameter (D 50 ) of the expanded natural graphite is in a range of 8 μm to 20 μm.

11 . The method of claim 1 , wherein the negative electrode structure comprises:
a negative electrode current collector; and a negative electrode active material layer on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer comprises the expanded natural graphite.

Assignees

• Lg Energy Solution Ltd

Inventors

• Kim Hyun Chul
• Chae Oh Byong
• Woo Sang Wook

Classifications

• H01M2004/027

  Negative electrodes · CPC title

• H01M2004/021

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

• H01M10/446

  Initial charging measures · CPC title

• H01M4/587 Primary

  for inserting or intercalating light metals · CPC title

• H01M4/1393 Primary

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