Pre-lithiation method of silicon oxide anode electrodes for secondary battery

Patent metadata

Field	Value
Publication number	US-2019305298-A1
Application number	US-201816465900-A
Country	US
Kind code	A1
Filing date	Apr 4, 2018
Priority date	May 19, 2017
Publication date	Oct 3, 2019
Grant date	—

Abstract

A method for pre-lithiating a silicon oxide negative electrode for a secondary battery, specifically a method for pre-lithiation by immersing the silicon oxide negative electrode in an electrolytic solution for wetting, and by applying pressure while a lithium metal is in direct contact with the wetted silicon oxide negative electrode. The silicon oxide negative electrode for a secondary battery manufactured through pre-lithiation provided in the present disclosure has improved initial irreversibility, and a secondary battery manufactured using such a silicon oxide negative electrode for a secondary battery has excellent charge/discharge efficiency.

First claim

1 . A method for pre-lithiating a silicon oxide negative electrode for a secondary battery, comprising;
a first step of immersing the silicon oxide negative electrode for the secondary battery in an electrolyte solution for wetting; and a second step of bringing the wetted silicon oxide negative electrode for the secondary battery into direct contact with a lithium metal.

2 . The method of claim 1 , wherein the second step is performed in the electrolyte solution in the first step.

3 . The method of claim 1 , wherein the second step comprises bringing the wetted silicon oxide negative electrode for the secondary battery into direct contact with the lithium metal with a force of 0.1 to 10 kgf per unit area of 1.5 cm 2 .

4 . The method of claim 1 , wherein the second step comprises bringing the wetted silicon oxide negative electrode for the secondary battery into direct contact with the lithium metal for 5 to 50 minutes.

5 . The method of claim 1 , wherein the first step comprises immersing the silicon oxide negative electrode for the secondary battery in the electrolyte solution for 10 minutes to 50 hours.

6 . The method of claim 1 , wherein the electrolyte solution in the first step is prepared by dissolving any one or two or more lithium salts selected from the group consisting of LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi, chloroborane lithium, a lower aliphatic lithium carboxylate and lithium tetraphenylborate in a solvent.

7 . The method of claim 6 , wherein the solvent is any one or a mixture of two or more selected from the group consisting of N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, gamma-butyrolactone and 1,2-dimethoxy ethane.

8 . A method for manufacturing a silicon oxide negative electrode for a secondary battery, comprising;
preparing a slurry by mixing an electrode active material comprising silicon oxide, a conducting material, and a binder; coating a current collector with the mixed slurry; pressing the coated current collector with a roller, and punching and drying the resultant to be a unit electrode; pre-lithiating the dried unit electrode according to the pre-lithiating method of claim 1 .

9 . A silicon oxide negative electrode for a secondary battery manufactured by the method of claim 8 .

10 . A secondary battery comprising the negative electrode of claim 9 .

11 . The secondary battery of claim 10 , wherein the secondary battery has a charge/discharge efficiency in a first charge/discharge cycle of 75 to 99%, which is expressed by the following Equation 1 at a current density of 0.1 C:

Charge


/


discharge



efficiency




(
%
)

=

Discharge



capacity

Charge



capacity

×
100.

[

Equation



1

]

Assignees

• Lg Chemical Ltd

Inventors

• Chae Oh Byong
• Song Jun Hyuk
• Kim Eun Kyung
• Kang Yoon Ah
• Woo Sang Wook

Classifications

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/0435 Primary

  Rolling or calendering · CPC title

• H01M4/1391 Primary

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/0459

  Electrochemical doping, intercalation, occlusion or alloying · CPC title

• H01M2004/027

  Negative electrodes · CPC title