Secondary-battery negative electrode, method for manufacturing same, and secondary battery

Patent metadata

Field	Value
Publication number	US-2023078924-A1
Application number	US-202117801934-A
Country	US
Kind code	A1
Filing date	Feb 25, 2021
Priority date	Feb 28, 2020
Publication date	Mar 16, 2023
Grant date	—

Abstract

A negative electrode for a secondary battery includes a negative electrode mixture layer having a negative electrode active material, a first layer covering at least a portion of a surface of the negative electrode active material, and a second layer covering at least a portion of a surface of the first layer, wherein the first layer includes a carbon material, and the second layer includes silicone.

First claim

1 . A negative electrode for a secondary battery comprising a negative electrode mixture layer having a negative electrode active material, a first layer covering at least a portion of a surface of the negative electrode active material, and a second layer covering at least a portion of a surface of the first layer, wherein the first layer includes a carbon material, and the second layer includes silicone.

2 . The negative electrode for a secondary battery of claim 1 , wherein the negative electrode active material includes a Si-containing material.

3 . The negative electrode for a secondary battery of claim 2 , wherein the Si-containing material includes a lithium ion conductive phase and Si particles dispersed in the lithium ion conductive phase, and
the lithium ion conductive phase is at least one selected from the group consisting of a silicon oxide phase, a silicate phase, and a carbon phase.

4 . The negative electrode for a secondary battery of claim 2 , wherein a content of the Si-containing material in the negative electrode mixture layer is 1 mass % to 30 mass %.

5 . The negative electrode for a secondary battery of claim 1 , wherein
the silicone is represented by {(R1) a SiO (y-a)/2 } c , where R1 is a substituted or non-substituted organic group having 1 to 8 carbon atoms, “a” is a rational number satisfying 0≤a≤2, and “c” is an integer satisfying 1≤c.

6 . The negative electrode for a secondary battery of claim 5 , wherein the R1 is at least one selected from the group consisting of an alkyl group, a vinyl group, an alkoxy group, an aryl group, an aryloxy group, a ketone group, a carboxyl group, and an ester group.

7 . The negative electrode for a secondary battery of claim 6 , wherein the R1 is an alkyl group, and the alkyl group is at least one selected from the group consisting of a methyl group and an ethyl group.

8 . The negative electrode for a secondary battery of claim 1 , wherein the silicone has at least one selected from the group consisting of a silanol group and an alkoxysilyl group.

9 . The negative electrode for a secondary battery of claim 1 , wherein a thickness of the second layer is 2 nm or more and 20 nm or less.

10 . The negative electrode for a secondary battery of claim 9 , wherein the thickness of the second layer is 5 nm or more and 10 nm or less.

11 . The negative electrode for a secondary battery of claim 1 , wherein the silicone includes a crosslinked structure in which one silicon atom and two or more oxygen atoms are bonded.

12 . A method for producing a negative electrode for a secondary battery, the method comprising:
preparing a slurry including a negative electrode active material, a first layer covering at least a portion of a surface of the negative electrode active material, and a dispersion medium, wherein the first layer includes a carbon material, applying the slurry on a negative electrode current collector, and volatilizing the dispersion medium, thereby forming a coating, preparing a solution including silicone and a solvent, and allowing the coating to contact the solution and volatilizing the solvent, to cover at least a portion of a surface of the first layer with a second layer, wherein
the second layer includes the silicone.

13 . The method for producing a negative electrode for a secondary battery of claim 12 , wherein the weight-average molecular weight of the silicone is 80 or more and 10000 or less.

14 . The method for producing a negative electrode for a secondary battery of claim 13 , wherein the weight-average molecular weight of the silicone is 1000 or less.

15 . A secondary battery comprising the negative electrode for a secondary battery of claim 1 , a positive electrode, and an electrolyte.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Badar Saifullah
• Tsujita Takuji
• Asaka Keisuke
• Suzuki Hirotetsu
• Sakata Motohiro

Classifications

• H01M10/0585

  of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/667

  in the form of layers, e.g. coatings · CPC title

• H01M4/1395

  of electrodes based on metals, Si or alloys · CPC title

• H01M4/0404 Primary

  by coating on electrode collectors · CPC title