Secondary battery

Patent metadata

Field	Value
Publication number	US-12322803-B2
Application number	US-202017439996-A
Country	US
Kind code	B2
Filing date	Jan 15, 2020
Priority date	Mar 26, 2019
Publication date	Jun 3, 2025
Grant date	Jun 3, 2025

Abstract

A secondary battery according to the present invention is provided with a positive electrode, a negative electrode and an electrolyte solution; the electrolyte solution contains water and a lithium salt; the negative electrode contains a negative electrode active material; a silane coupling agent, which is reductively decomposed at a potential that is higher than the reductive decomposition potential of water, is adhered to the surface of the negative electrode active material; and the silane coupling agent contains fluorine as a constituent element.

First claim

The invention claimed is:

1. A secondary battery comprising a positive electrode, a negative electrode, and an electrolyte solution, wherein
the electrolyte solution contains water and a lithium salt; and
the negative electrode includes a negative electrode active material, wherein, to a surface of the negative electrode active material, a silane coupling agent is adhered, which is reductively decomposed at a potential higher than a reductive decomposition potential of water, and wherein the silane coupling agent contains fluorine as a constituent element,
wherein the silane coupling agent is fluoroalkylsilane represented by

Y1 is represented by C n F 2n+1 (5≤n≤10); Y2 is represented by (CH2) n where n is an integer of 0 to 5, and may be linear or branched; and each of R1, R2 and R3 independently is an alkoxy group, an alkyl group, an amino group, a halogen atom, or a hydrogen atom, and
wherein the electrolyte solution contains 4 mol or less of the water relative to 1 mol of the lithium salt,
wherein the fluoroalkylsilane has a fluorination ratio of 0.49 or higher.

2. The secondary battery according to claim 1 , wherein the negative electrode active material contains a carbon material as a main component.

3. The secondary battery according to claim 1 , wherein a reduction decomposition potential of the silane coupling agent is 2.1 V or higher as determined with reference to Li.

4. The secondary battery according to claim 1 , wherein each of R1, R2, and R3 is independently represented by OC n H 2n+1 (1≤n≤5) or C n H 2n+1 (1≤n≤5).

5. The secondary battery according to claim 1 , wherein the fluoroalkylsilane includes at least one of C 5 F 11 CH 2 CH 2 —Si(OCH 3 ) 3 , C 6 F 13 CH 2 CH 2 —Si(OCH 3 ) 3 , and C 8 F 17 CH 2 CH 2 —Si(OCH 3 ) 3 .

6. The secondary battery according to claim 1 , wherein a content of the silane coupling agent is in a range from 0.01% by mass to 10% by mass relative to a mass of the negative electrode active material.

7. A secondary battery comprising a positive electrode, a negative electrode, and an electrolyte solution, wherein
the electrolyte solution contains water and a lithium salt; and
the negative electrode includes a negative electrode active material, and on a surface of the negative electrode active material, a coating is formed by reductive decomposition of a silane coupling agent which contains fluorine as a constituent element and which is reductively decomposed at a potential higher than a reductive decomposition potential of water,

wherein the silane coupling agent is fluoroalkylsilane represented by

Y1 is represented by C n F 2n+1 (5≤n≤10); Y2 is represented by (CH2) n where n is an integer of 0 to 5, and may be linear or branched; and each of R1, R2 and R3 independently is an alkoxy group, an alkyl group, an amino group, a halogen atom, or a hydrogen atom.

8. The secondary battery according to claim 7 , wherein the coating includes LiF and SiO x (0<x<2).

9. The secondary battery according to claim 8 , wherein the SiO x is such that valency of Si decreases in the coating from a surface side toward a deepest side.

10. The secondary battery according to claim 8 , wherein the LiF is unevenly locally distributed toward the deepest side of the coating.

11. The secondary battery according to claim 1 , wherein the lithium salt includes a salt having a lithium ion and an imide anion.

12. The secondary battery according to claim 1 , wherein the lithium salt includes lithium bis(trifluoromethanesulfonyl)imide, LiTFSI.

13. The secondary battery according to claim 1 , wherein the electrolyte solution contains 6% by mass to 50% by mass of the water.

14. The secondary battery according to claim 7 , wherein the lithium salt includes a salt having a lithium ion and an imide anion.

15. The secondary battery according to claim 7 , wherein the lithium salt includes lithium bis(trifluoromethanesulfonyl)imide, LiTFSI.

16. The secondary battery according to claim 7 , wherein the electrolyte solution contains 6% by mass to 50% by mass of the water.

17. The secondary battery according to claim 7 ,
wherein the electrolyte solution contains 4 mol or less of the water relative to 1 mol of the lithium salt.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Matsubara Kenji
• Hojo Nobuhiko
• Takeuchi Masanobu
• Fukui Atsushi

Classifications

• H01M10/4235 Primary

  Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence) · CPC title

• H01M10/36

  Accumulators not provided for in groups H01M10/05-H01M10/34 · CPC title

• H01M2300/0002

  Aqueous electrolytes · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title