Negative electrode for lithium secondary battery, method for pre-lithiation thereof, and lithium secondary battery including same

Patent metadata

Field	Value
Publication number	US-12113203-B2
Application number	US-201917254516-A
Country	US
Kind code	B2
Filing date	Jul 4, 2019
Priority date	Jul 6, 2018
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

A negative electrode for a lithium secondary battery, a negative electrode in which the negative electrode is pre-lithiated, a method of manufacturing the negative electrode, and a lithium secondary battery including the negative electrode. The pre-lithiated negative electrode may increase the capacity and improve the electrochemical performance of a lithium secondary battery by securing the initial reversibility of a negative electrode.

First claim

The invention claimed is:

1. A method for pre-lithiation of a negative electrode for a lithium secondary battery, the method comprising:
forming a first negative electrode active material layer on a surface of a negative electrode current collector, wherein said first negative electrode active material layer comprises a silicon-based negative electrode active material and is selected from the group consisting of silicon, a silicon-based alloy, and SiO x , wherein 0<x≤2;
forming a lithium metal layer comprising a lithium metal on a surface of the first negative electrode active material layer;
forming a second negative electrode active material layer on a surface of the lithium metal layer, wherein said second negative electrode active material layer comprises a silicon-based negative electrode active material and is selected from the group consisting of silicon, a silicon-based alloy, and SiO x , wherein 0<x≤2, wherein said second negative electrode active material is the same or different from said first negative electrode active material; and
impregnating the resulting negative electrode for the lithium secondary battery with a pre-lithiation solution to perform pre-lithiation, wherein the pre-lithiation solution comprises an ionizable lithium salt and an organic solvent, and the impregnation is performed at a temperature of 20° C. to 70° C. for 2 hours to 36 hours.

2. The method of claim 1 , wherein the ionizable lithium salt contains Li+ as a cation, and an anion selected from the group consisting of F − , Cl − , Br − , I − , NO 3 − , N(CN) 2 − , BF 4 − , ClO 4 − , AlO 4 − , AlCl 4 − , PF 6 − , SbF 6 − , AsF 6 − , B 10 Cl 10 − , BF 2 C 2 O 4 − , BC 4 O 8 − , PF 4 C 2 O 4 − , PF 2 C 4 O 8 − , (CF 3 ) 2 PF 4 − , (CF 3 ) 3 PF 3 − , (CF 3 ) 4 PF 2 − , (CF 3 ) 5 PF − , (CF 3 ) 6 P − , CF 3 SO 3 − , C 4 F 9 SO 3 − , CF 3 CF 2 SO 3 − , (CF 3 SO 2 ) 2 N − , (FSO 2 ) 2 N − , CF 3 CF 2 (CF 3 ) 2 CO − , (CF 3 SO 2 ) 2 CH − , CH 3 SO 3 − , CF 3 (CF 2 ) 7 SO 3 − , CF 3 CO 2 − , CH 3 CO 2 − , SCN − , and (CF 3 CF 2 SO 2 ) 2 N − ; and
wherein the organic solvent is one or more selected from the group consisting of a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, and a linear ester-based organic solvent.

3. The method of claim 1 , wherein the first negative electrode active material layer further comprises a carbon-based negative electrode active material, and a weight ratio of the silicon-based negative electrode active material to the carbon-based negative electrode active material in the first negative electrode active material layer is 1:99 to 50:50.

4. The method of claim 3 , wherein the weight ratio of the silicon-based negative electrode active material to the carbon-based negative electrode active material is 5:95 to 20:80.

5. The method of claim 3 , wherein the carbon-based negative electrode active material is selected from the group consisting of artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon.

6. The method of claim 1 , wherein the second negative electrode active material layer further comprises a carbon-based negative electrode active material, and a weight ratio of the silicon-based negative electrode active material to the carbon-based negative electrode active material in the second negative electrode active material layer is 1:99 to 50:50.

7. The method of claim 6 , wherein the weight ratio of the silicon-based negative electrode active material to the carbon-based negative electrode active material is 5:95 to 20:80.

8. The method of claim 6 , wherein the carbon-based negative electrode active material is selected from the group consisting of artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon.

9. The method of claim 1 , wherein the first negative electrode active material layer and the second negative electrode active material layer each further comprises a carbon-based negative electrode active material, and a weight ratio of the silicon-based negative electrode active material to the carbon-based negative electrode active material in each of the first negative electrode active material layer and the second negative electrode active material layer is 1:99 to 50:50.

10. The method of claim 1 , wherein said forming of the lithium metal layer is by adding and dispersing a lithium metal powder and a binder in an organic solvent, and then evenly applying the solution onto the formed first negative electrode active material layer.

11. The method of claim 1 , wherein said forming the lithium metal layer is by placing and pressing a lithium metal foil onto the formed first negative electrode active material layer.

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

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

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/1393

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

• H01M4/382

  Lithium (H01M4/405 takes precedence) · CPC title

• H01M4/0445

  Forming after manufacture of the electrode, e.g. first charge, cycling · CPC title

• H01M10/049

  Processes for forming or storing electrodes in the battery container · CPC title