Non-porous battery separator and methods of making same

Patent metadata

Field	Value
Publication number	US-2019181412-A1
Application number	US-201916280357-A
Country	US
Kind code	A1
Filing date	Feb 20, 2019
Priority date	Sep 13, 2016
Publication date	Jun 13, 2019
Grant date	—

Abstract

This invention provides a non-porous battery separator comprising an elastomeric material, wherein the elastomeric material is permeable to metal ions but not appreciably permeable to other chemical species. A battery comprising the non-porous battery separator is also provided. Methods of making a non-porous battery separator are also provided.

First claim

1 . A non-porous battery separator comprising an elastomeric material, wherein the elastomeric material is permeable to metal ions but not appreciably permeable to other chemical species.

2 . The non-porous battery separator of claim 31 , wherein the elastomeric material is either partially or fully immersed in an electrolyte solution.

3 . The non-porous battery separator of claim 2 , wherein the electrolyte solution is an organic liquid electrolyte solution.

4 . The non-porous battery separator of claim of claim 3 , wherein the organic liquid electrolyte solution is 1 M LiPF 6 in EC/MEC (3:7 v/v).

5 . The non-porous battery separator of claim 1 , wherein the thickness of the separator is from about 1 μm to about 200 μm.

6 . The non-porous battery separator of claim 1 , wherein the diameter of the separator is from about 3 mm to about 50 mm.

7 . The non-porous separator of claim 1 , having a tensile strength from about 50 Pa to about 50 MPa.

8 . The non-porous battery separator of claim 1 , wherein the separator has an electrical resistance from about 100 Ohms to about 5000 Ohms.

9 . The non-porous battery separator of claim 1 , wherein there are no visible pores in the elastomeric material at a resolution of 1 nm.

10 . The non-porous battery separator of claim 1 , wherein the non-porous battery separator is impermeable to lithium dendrites.

11 . The non-porous battery separator of claim 1 , wherein the permeable metal ions are Li + .

12 . A battery comprising the non-porous battery separator of claim 1 .

13 . The battery of claim 12 , wherein the battery is a Li-ion battery.

14 . The battery of claim 12 , wherein the Coulombic efficiency is greater than about 50% after the 120th charge cycle.

15 . The battery of claim 12 , wherein the Coulombic efficiency is greater than about 75% after the 70th charge cycle.

16 . The battery of claim 12 , wherein the Coulombic efficiency is from about 75% to about 80% after the 6 th charge cycle.

17 . The battery of claim 12 , wherein there is no observed drop in voltage after 50 cycles.

18 . The battery of claim 12 , wherein the current density of the cell is 10 mA cm −2 and the areal capacity is 10 mAh cm 2 .

19 . The battery of claim 18 , further comprising a PTFE washer between the anode and the separator.

20 . The non-porous battery separator of claim 1 , wherein the elastomeric material applies a compressive stress when the non-porous battery separator is mechanically coupled to a lithium electrode.

21 . The non-porous battery separator of claim 1 , wherein the elastomeric material is deformable with a strain up to 100%.

Assignees

• Massachusetts Inst Technology

Inventors

• Li Ju
• Bazant Martin Z
• Bai Peng
• Wang Chang An
• Liu Kai

Classifications

• H01M10/0525 Primary

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

• H01M50/494

  Tensile strength · CPC title

• H01M50/469

  tubular or cylindrical · CPC title

• H01M50/489

  Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties · CPC title

• H01M50/414

  Synthetic resins, e.g. thermoplastics or thermosetting resins · CPC title