METHOD FOR FORMING LITHIUM METAL AND INORGANIC MATERIAL COMPOSITE THIN FILM AND METHOD FOR PRE-LITHIATION OF NEGATIVE ELECTRODE FOR LITHIUM SECONDARY BATTERY BY USING SAME

• US 20200136128A1
• Filed: 08/03/2018
• Published: 04/30/2020
• Est. Priority Date: 08/10/2017
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: WOO, Sang Wook, KIM, Eun Kyung, KANG, Yoon Ah, SONG, Jun Hyuk, CHAE, Oh Byong
• Granted Patent: US 11,316,145 B2
• Time in Patent Office: Days
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 4/0433 Molding
• CPC Class Codes: H01M 4/0435 Rolling or calendering
• CPC Class Codes: H01M 4/0459 Electrochemical doping, intercalation, occlusion or alloying
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/0483 by methods including the handling of a melt H01M4/0438, take precedence
• CPC Class Codes: H01M 4/049 Manufacturing of an active layer by chemical means
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/1391 of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method for pre-lithiation of a negative electrode and a negative electrode formed by the method, the method including forming a mixture of inorganic material powder and molten lithium, forming a lithium metal-inorganic material composite ribbon, rolling the ribbon into a film and bonding the lithium metal-inorganic material composite film on a surface of a negative electrode to form a lithium metal-inorganic material composite layer on the surface of the negative electrode. This method reduces the deterioration of lithium during application of a mixture slurry and a negative electrode for a secondary battery, manufactured by the method for pre-lithiation, has improved initial irreversibility, and a secondary battery manufactured using such a negative electrode has excellent charging and discharging efficiency.

Claims

1. A method for pre-lithiating a negative electrode, the method comprising:

adding an inorganic powder to molten lithium to form a mixture;

extruding the mixture and cooling the mixture to prepare a lithium metal-inorganic composite ribbon having a thickness of 100 μ

m to 200 μ

m;

rolling the lithium metal-inorganic composite ribbon to produce a lithium metal-inorganic composite film; and

bonding the lithium metal-inorganic composite film on a surface of the negative electrode to form a lithium metal-inorganic composite layer on the surface of the negative electrode.

2. The method of claim 1, wherein a thickness of the lithium metal-inorganic composite layer is 1 μ

m to 50 μ

m.

3. The method of claim 1, wherein the inorganic powder comprises at least one selected from the group consisting of alumina (Al₂O₃), titanium dioxide (TiO₂), zirconium dioxide (ZrO₂), silicon dioxide (SiO₂), tin oxide (SnO₂), cerium oxide (CeO₂), magnesium oxide (MgO), calcium oxide (CaO), and yttria (Y₂O₃).

4. The method of claim 1, wherein a mixing ratio of the molten lithium and the inorganic powder is 70 to 85% by volume of the molten lithium and 15 to 30% by volume of the inorganic powder.

5. The method of claim 1, further comprising

mixing a binder with the molten lithium or the mixture of the molten lithium and inorganic powder.

6. The method of claim 1, wherein the lithium metal-inorganic composite layer does not remain in a metallic form of lithium after an initial activation charge.

7. The method of claim 1, wherein the inorganic powder has a particle diameter of 0.1 μ

m to 10 μ

m.

8. The method of claim 1, wherein the negative electrode comprises silicon oxide.

9. A negative electrode for a secondary battery, wherein the negative electrode is produced by a process comprising the pre-lithiation method according to claim 1.

10. A secondary battery, comprising the negative electrode according to claim 9, a separator and a positive electrode.