Negative electrode for rechargeable lithium battery, rechargeable lithium battery including same and method of preparing rechargeable lithium battery

Patent metadata

Field	Value
Publication number	US-9793539-B2
Application number	US-201313861332-A
Country	US
Kind code	B2
Filing date	Apr 11, 2013
Priority date	Apr 30, 2012
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A negative electrode for a rechargeable lithium battery that includes a negative active material layer including a carbon-based material having a peak of about 20 degrees to 30 degrees at a (002) plane in an X-ray diffraction pattern using a CuKα ray, and an SEI (solid electrolyte interface) passivation film including at least one material selected from an organic material and an inorganic material and having an average thickness of about 10 nm to about 50 nm on the surface of the active material layer of the electrode.

First claim

What is claimed is:

1. A negative electrode for a rechargeable lithium battery, the negative electrode comprising:
a negative active material layer comprising a carbon-based material having a peak of about 20 degrees to 30 degrees at a (002) plane in an X-ray diffraction pattern using a CuKα ray; and
an SEI (solid electrolyte interface) passivation film on a surface of the negative active material layer of the negative electrode and having an average thickness of about 20 nm to about 46 nm, the SEI passivation film comprising:
an organic material and LiF;
wherein the LiF is included in an amount of about 31 weight % to about 53 weight % based on the total weight of the SEI passivation film;
a weight % of the LiF being smaller than a weight % of the organic material at the surface of the negative active material layer of the negative electrode.

2. The negative electrode of claim 1 , wherein the carbon-based material comprises at least one selected from soft carbon and graphite.

3. The negative electrode of claim 1 , wherein the carbon-based material has an average particle diameter of about 1 um to about 20 um.

4. The negative electrode of claim 1 , wherein the organic material comprises at least one selected from ROCO 2 Li (R is a C1 to C10 alkyl group), R 1 (OCO 2 CH 2 CH 2 ) n Li (R 1 is a C1 to C10 alkyl group, and n is an integer ranging from about 1 to about 25), R 2 (CH 2 CH 2 O) m Li (R 2 is a C1 to C10 alkyl group, and m is an integer ranging from about 1 to about 25), and NR 3 R 4 R 5 (R 3 , R 4 and R 5 are C1 to C10 alkyl groups).

5. The negative electrode of claim 1 , wherein the inorganic material comprises at least one selected from LIF, Li 2 O, Li 2 CO 3 and Li x PF y O (0<x≦1, 1≦y≦4).

6. The negative electrode of claim 1 , wherein the SEI passivation film comprises:
a first layer comprising the inorganic material in an amount ranging from greater than or equal to about 60 weight % and the organic material in an amount ranging from less than or equal to about 40 weight % based on the entire weight of the first layer; and
a second layer comprising the organic material in an amount ranging from greater than or equal to about 60 weight % and the inorganic material in an amount ranging from less than or equal to 40 weight % based on the entire weight of the second layer,
wherein the first layer and the second layer have equal thicknesses, and
wherein the first layer forms the surface of the SEI passivation film, and the second layer is beneath the first layer.

7. The negative electrode of claim 6 , wherein the first layer of the SEI passivation film comprises LIE in an amount ranging from about 60 weight % to about 70 weight % based on the entire weight of the first layer, and
the second layer of the SEI passivation film comprises LiF in an amount ranging from about 0.1 weight % to 10 weight % based on the entire weight of the second layer.

8. The negative electrode of claim 1 , wherein the SEI passivation film comprises:
a first layer comprising LiF in an amount ranging from about 60 weight % to about 70 weight % based on the entire weight of the first layer; and
a second layer comprising LiF in an amount ranging from about 0.1 weight % to 10 weight % based on the entire weight of the second layer,
wherein the first layer and the second layer have equal thicknesses, and
wherein the first layer forms the surface of the SEI passivation film, and the second layer is beneath the first layer.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Sheem Kyeu-Yoon
• Kim Jake

Classifications

• H01M4/0404

  by coating on electrode collectors · CPC title

• H01M2004/021

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

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/133 Primary

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

• H01M10/0525

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