Separator including porous substrate and coating layer of acrylic copolymer, organic filler, and inorganic particles, and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-12230834-B2
Application number	US-201917414043-A
Country	US
Kind code	B2
Filing date	Jul 23, 2019
Priority date	Jan 16, 2019
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

The present invention relates to a separator for a lithium secondary battery, and a lithium secondary battery including the same. The separator includes a porous substrate, and a coating layer on at least one surface of the porous substrate, wherein the coating layer includes an acrylic copolymer including a first structural unit derived from (meth)acrylamide, and a second structural unit including at least one of a structural unit derived from (meth)acrylic acid or (meth)acrylate, and a structural unit derived from (meth)acrylamidosulfonic acid or a salt thereof; an organic filler; and inorganic particles, wherein the organic filler is included in an amount of 0.1 to 50 wt % based on a total amount of the organic filler and the inorganic particles.

First claim

The invention claimed is:

1. A separator for a lithium secondary battery, comprising
a porous substrate, and
a coating layer on at least one surface of the porous substrate,
wherein the coating layer comprises
an acrylic copolymer;
an organic filler; and
inorganic particles,
wherein the acrylic copolymer comprises a first structural unit derived from (meth)acrylamide, and a second structural unit derived from (meth)acrylic acid or (meth)acrylate, and a third structural unit derived from (meth)acrylamidosulfonic acid or a salt thereof represented by one selected from Chemical Formula 4, Chemical Formula 5, Chemical Formula 6, and a combination thereof,

wherein, in Chemical Formula 4 to Chemical Formula 6,
R 4 to R 6 are each independently hydrogen or a C1 to C6 alkyl group,
L 1 to L 3 are each independently a substituted or unsubstituted C3 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C3 to C20 heterocyclic group,
a, b, and c are each independently one of integers of 1 or 2, and
M is an alkali metal,
wherein the organic filler is included in an amount of 0.1 to 50 wt % based on a total amount of the organic filler and the inorganic particles, and
wherein the first structural unit is included in an amount of 55 mol % to 95 mol % based on 100 mol % of the acrylic copolymer, and the total amount of the second structural unit and the third structural unit is included in an amount of 5 mol % to 45 mol % based on 100 mol % of the acrylic copolymer.

2. The separator of claim 1 , wherein the coating layer has a thickness of 1 μm to 5 μm.

3. The separator of claim 1 , wherein the average particle diameter of the organic filler is 0.1 μm to 0.5 μm.

4. The separator of claim 1 , wherein the organic filler is at least one organic compound selected from an acrylate-based compound and a derivative thereof, a diallyl phthalate-based compound and a derivative thereof, a polyimide-based compound and a derivative thereof, a copolymer thereof, and a mixture thereof.

5. The separator of claim 1 , wherein the average particle diameter of the inorganic particles is 0.3 μm to 0.7 μm.

6. The separator of claim 1 , wherein the inorganic particles comprise Al 2 O 3 , SiO 2 , TiO 2 , SnO 2 , CeO 2 , MgO, NiO, CaO, GaO, ZnO, ZrO 2 , Y 2 O 3 , SrTiO 3 , BaTiO 3 , Mg(OH) 2 , boehmite, or a combination thereof.

7. The separator of claim 1 , wherein the second structural unit derived from the (meth)acrylic acid or (meth)acrylate is included in an amount of 0 mol % to 40 mol % based on 100 mol % of the acrylic copolymer, and the third structural unit derived from the (meth)acrylamidosulfonic acid or the salt thereof is included in an amount of 0 mol % to 10 mol % based on 100 mol % of the acrylic copolymer.

8. The separator of claim 1 , wherein
the first structural unit derived from (meth)acrylamide is represented by Chemical Formula 1, and
the second structural unit derived from the (meth)acrylic acid or (meth)acrylate is represented by one of Chemical Formula 2, Chemical Formula 3, and a combination thereof:

wherein, in Chemical Formula 1 to Chemical Formula 3,
R 1 to R 3 are each independently hydrogen or a C1 to C6 alkyl group,
R 7 is a substituted or unsubstituted C1 to C20 alkyl group.

9. The separator of claim 1 , wherein a weight average molecular weight of the acrylic copolymer is 350,000 to 970,000.

10. The separator of claim 1 , wherein a volume ratio of the inorganic particle and the organic filler is 40:1 to 1:3.

11. The separator of claim 1 , wherein a weight ratio of the acrylic copolymer:organic filler and inorganic particle is 1:20 to 1:40.

12. A lithium secondary battery, comprising
a positive electrode, a negative electrode, and the separator of claim 1 between the positive electrode and the negative electrode.

13. A separator for a lithium secondary battery, comprising
a porous substrate, and
a coating layer on at least one surface of the porous substrate,
wherein the coating layer comprises
an acrylic copolymer;
an organic filler; and
inorganic particles,
wherein the acrylic copolymer comprises a first structural unit derived from (meth)acrylamide, and a second structural unit derived from (meth)acrylic acid or (meth)acrylate, and a third structural unit derived from (meth)acrylamidosulfonic acid or a salt thereof represented by one selected from Chemical Formula 4, Chemical Formula 5, Chemical Formula 6, and a combination thereof,

wherein, in Chemical Formula 4 to Chemical Formula 6,
R 4 to R 6 are each independently hydrogen or a C1 to C6 alkyl group,
L 1 to L 3 are each independently a substituted or unsubstituted C3 to C10 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, or a substituted or unsubstituted C3 to C20 heterocyclic group,
a, b, and c are each independently one of integers of 1 or 2, and
M is an alkali metal,
wherein the organic filler is included in an amount of 0.1 to 50 wt % based on a total amount of the organic filler and the inorganic particles, and
wherein the first structural unit derived from the (meth)acrylamide is included in an amount of 80 mol % to 85 mol % based on 100 mol % of the acrylic copolymer, the second structural unit derived from the (meth)acrylic acid or (meth)acrylate is included in an amount of 10 mol % to 15 mol % based on 100 mol % of the acrylic copolymer, and the third structural unit derived from the (meth)acrylamidosulfonic acid or the salt thereof is included in an amount of 5 mol % to 10 mol % based on 100 mol % of the acrylic copolymer.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Gain
• Choi Yeonjoo
• Kim Yangseob
• Kim Yongkyoung
• Seo Dongwan
• Lee Jungyoon
• Choi Hyeonsun

Classifications

• H01M50/443

  Particulate material · CPC title

• H01M10/0525

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

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M50/46

  Separators, membranes or diaphragms characterised by their combination with electrodes · CPC title

• H01M50/463

  Separators, membranes or diaphragms characterised by their shape · CPC title