Separator of lithium ion battery and method for making the same

Patent metadata

Field	Value
Publication number	US-2018277811-A1
Application number	US-201815992173-A
Country	US
Kind code	A1
Filing date	May 30, 2018
Priority date	Nov 30, 2015
Publication date	Sep 27, 2018
Grant date	—

Abstract

A lithium ion battery separator comprises a separator substrate and two halloysite nanotube coatings, wherein the separator substrate has two opposite surfaces, and the two halloysite nanotube coatings are respectively disposed on the two opposite surfaces of the separator substrate. A method for making the lithium ion battery separator is further provided.

First claim

What is claimed is:

1 . A lithium ion battery separator comprising a separator substrate having two opposite surfaces, and a halloysite nanotube coating disposed on each of the two opposite surfaces.

2 . The lithium ion battery separator of claim 2 , wherein the separator substrate is a porous structure defining a plurality of micropores.

3 . The lithium ion battery separator of claim 2 , wherein the halloysite nanotube coating is coated on each of the two opposite surfaces of the separator substrate.

4 . The lithium ion battery separator of claim 2 , wherein the separator substrate is a polyolefin microporous membrane.

5 . The lithium ion battery separator of claim 1 , wherein the halloysite nanotube coating comprises a plurality of halloysite nanotubes uniformly mixed with a polymer binder.

6 . The lithium ion battery separator of claim 5 , wherein surfaces of the plurality of halloysite nanotubes are modified with a silane coupling agent.

7 . The lithium ion battery separator of claim 6 , wherein the silane coupling agent has a molecular formula of CH 3 (CH 2 ) n SiX 3 , n is 1 to 17, and X is an ethoxy group, a methoxy group, a chloro group, a methoxyethoxy group, or an acetoxy group.

8 . The lithium ion battery separator of claim 5 , wherein the polymer binder is a polyurethane, polyvinylidene fluoride, polyimide, or combinations thereof.

9 . The lithium ion battery separator of claim 1 , wherein a thickness of the halloysite nanotube coating is in a range from about 3 μm to about 5 μm.

10 . The lithium ion battery separator of claim 1 , wherein an average length of the plurality of halloysite nanotubes is in a range from about 1 μm to about 15 μm, and an average diameter of the plurality of halloysite nanotubes is in a range from about 15 nm to about 100 nm.

11 . A method for making the lithium ion battery separator, comprising:
providing a halloysite nanotube raw material, a polymer binder, and a solvent; dispersing the halloysite nanotube raw material and the polymer binder into the solvent, thereby obtaining a coating slurry comprising a plurality of halloysite nanotubes and the polymer binder; and providing a separator substrate having two opposite surfaces, and coating the coating slurry on the two opposite surfaces respectively to form two halloysite nanotube coatings.

12 . The method of claim 11 , wherein the halloysite nanotube raw material is a plurality of silane coupling agent modified halloysite nanotubes.

13 . The method of claim 12 , wherein the silane coupling agent has a molecular formula of CH 3 (CH 2 ) n SiX 3 , n is 1 to 17, and X is an ethoxy group, a methoxy group, a chloro group, a methoxyethoxy group, an acetoxy group, or combinations thereof.

14 . The method of claim 11 , wherein the solvent is tetrahydrofuran, chloroform, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, or combinations thereof.

15 . The method of claim 11 , wherein the polymer binder is a polyurethane, a polyvinylidene fluoride, a polyimide, or combinations thereof.

16 . The method of claim 11 , wherein the separator substrate is a polyolefin microporous membrane.

17 . The method of claim 11 , wherein in the coating slurry, a mass ratio of the polymer binder to the plurality of halloysite nanotubes is in a range from about 0.1 to about 0.4.

Assignees

• Univ Tsinghua

Inventors

• Liu Zhen
• Shang yu-ming
• He xiang-ming
• Wang Li

Classifications

• H01M10/0525 Primary

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

• H01M4/366

  as layered products · CPC title

• H01M4/623

  fluorinated polymers · CPC title

• H01M50/403

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• H01M50/457

  comprising three or more layers · CPC title