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EP-4742410-A1 - SEPARATOR FOR RECHARGEABLE BATTERY AND RECHARGEABLE BATTERY INCLUDING THE SAME

EP4742410A1EP 4742410 A1EP4742410 A1EP 4742410A1EP-4742410-A1

Abstract

Provided are a separator for a rechargeable lithium battery, and a rechargeable lithium battery including the separator. The separator includes one or more fibrous layers, wherein at least one of the fibrous layers includes a fiber network of fibers containing a first copolymer, and at least one of the fibrous layers includes a polyimide-based fiber, or a core-shell fiber containing a polyimide-based resin. The first copolymer includes a copolymer of a monomer mixture, which includes a first structural unit including a unit derived from an aromatic based unsaturated monomer; a second structural unit derived from a (meth)acryl-based monomer containing an alkyl group with 4 or more carbon atoms in the main chain in an ester moiety; and a third structural unit derived from a monomer containing a sulfonic acid group.

Inventors

  • GU, JA YEON
  • SEO, DONG WAN
  • KIM, GA IN
  • PARK, EUN JIN
  • AHN, Hwi Chan

Assignees

  • SAMSUNG SDI CO., LTD.

Dates

Publication Date
20260513
Application Date
20251106

Claims (15)

  1. A separator for a rechargeable lithium battery, the separator comprising: one or more fibrous layers, wherein at least one of the fibrous layers includes a fiber network of fibers containing a first copolymer, at least one of the fibrous layers includes a polyimide-based fiber, or a core-shell fiber containing a polyimide-based resin, the first copolymer includes a copolymer of a monomer mixture, which includes a first structural unit including a unit derived from an aromatic based unsaturated monomer; a second structural unit derived from a (meth)acryl-based monomer containing an alkyl group with 4 or more carbon atoms in the main chain in an ester moiety; and a third structural unit derived from a monomer containing a sulfonic acid group, and the first structural unit, the second structural unit, and the third structural unit are respectively included at a range of from about 5 mol% to about 80 mol%, a range of from about 10 mol% to about 60 mol%, and a range of from about 5 mol% to about 80 mol% with respect to 100 mol% of the copolymer.
  2. The separator of claim 1, wherein the first copolymer comprises an adhesive binder.
  3. The separator of claim 1 or 2, wherein the first copolymer has a glass transition temperature in a range of from about 60 °C to about 80 °C.
  4. The separator of any one of claims 1 to 3, wherein the sum of the contents of the first structural unit, the second structural unit, and the third structural unit in the copolymer is about 95 mol% or more.
  5. The separator of any one of claims 1 to 4, wherein a unit derived from the aromatic based unsaturated monomer is represented by Chemical Formula 1, in Chemical Formula 1, R 1 and R 2 each independently comprises hydrogen or a substituted or unsubstituted C1 to C5 alkyl group, and Ar comprises a substituted or unsubstituted, monocyclic or polycyclic C6 to C20 aryl group), the second structural unit is represented by Chemical Formula 4, in Chemical Formula 4, R 7 and R 8 each independently comprises hydrogen or a methyl group, L 2 comprises a substituted or unsubstituted, linear or branched C4 to C30 alkyl group), and the third structural unit is represented by any one of Chemical Formulas 5, 6, and 7: in Chemical Formulas 5 to 7, R 9 , R 10 , R 11 , R 12 , R 13 , and R 14 each independently comprises hydrogen or a C1 to C3 alkyl group, L 3 , L 5 , and L 7 each independently comprises -C(=O)-, -C(=O)O-, -OC(=O)-, -O-, or -C(=O)NH-, L 4 , L 6 , and L 8 each independently comprises a substituted or unsubstituted C1 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, and a, b, c, d, e, and f are each independently an integer in a range of 0 to 2, and in Chemical Formula 6, M comprises an alkali metal.
  6. The separator of any one of claims 1 to 5, wherein the first structural unit further comprises a unit derived from a (meth)acryl-based monomer containing an alkyl group having 1 to 3 carbon atoms in the main chain in an ester moiety.
  7. The separator of claim 6, wherein the unit derived from the (meth)acryl-based monomer is a unit represented by Chemical Formula 3: in Chemical Formula 3, R 5 and R 6 each independently comprises hydrogen or a methyl group, L 1 comprises a substituted or unsubstituted, linear or branched C1 to C3 alkyl group.
  8. The separator of any one of claims 1 to 7, wherein the separator comprises a multi-layer separator including the fibrous layer; and/or wherein the multi-layer separator comprises one or more, or two or more, fibrous layers including a fiber network of fibers containing the first copolymer.
  9. The separator of claim 8, wherein the multi-layer separator further comprises one or more, or two or more, fibrous layers including a fiber network of fibers containing one or more types of second copolymers.
  10. The separator of claim 8 or 9, wherein the multi-layer separator comprises one or more, or two or more, fibrous layers including a network of core-shell-type fibers, and the first copolymer is included in the core or shell of the core-shell-type fiber, optionally, wherein the core-shell-type fiber further comprises a second copolymer; and/or wherein the multi-layer separator further comprises one or more types of a fibrous layer including a network of fibers containing the first copolymer and a fibrous layer including a network of fibers containing one or more types of second copolymers.
  11. The separator of claim 8, wherein the multi-layer separator comprises one or more, or two or more, fibrous layers including a network of fibers containing a mixture of the first copolymer and a second copolymer; and/or wherein the multi-layer separator further comprises one or more types of a fibrous layer including a network of fibers containing the first copolymer, and a fibrous layer including a network of fibers containing one or more types of second copolymers.
  12. The separator of any one of claims 9 to 11, wherein the second copolymer includes any one or more of polyacrylonitrile, polyaniline, polypyrrole, polyrhodanine, melanine, polyurea, polyvinyl chloride, polyvinyl alcohol, polyethylene oxide, polymethyl methacrylate, polyacrylic acid, polylactic acid, polyimide, polyamideimide, polyaramid, polybenzylimidazole, polypropylene, resorcinol-formaldehyde resin, melamine-formaldehyde resin, pitch, sucrose, glucose, cellulose, and polyvinylidene fluoride.
  13. The separator of any one of claims 1 to 12, wherein the separator has no porous substrate.
  14. The separator of any one of claims 1 to 13, wherein the separator has a thickness of about 8 µm or less.
  15. A rechargeable lithium battery, comprising: a positive electrode; a negative electrode; and the separator of any one of claims 1 to 14 located between the positive electrode and the negative electrode.

Description

CROSS-REFERENCE TO RELATED APPLICATION BACKGROUND 1. Field of the Disclosure The present disclosure relates to a separator for a rechargeable battery, and a rechargeable battery including the separator 2. Discussion of Related Art With increasing presence of electronic devices using batteries such as, e.g., mobile phones, notebook computers, electric vehicles, and the like, the demand for secondary batteries having high energy density and high capacity is increasing. Therefore, improving the performance of rechargeable lithium batteries may be advantageous. A rechargeable lithium battery includes a positive electrode and a negative electrode that contain an active material capable of the intercalation and deintercalation of lithium ions, and produces electrical energy by oxidation and reduction reactions when the lithium ions are intercalated into and deintercalated from the positive electrode and the negative electrode. SUMMARY The present disclosure describes a separator for a rechargeable battery, which has no porous substrate and provides desired or improved heat resistance, low membrane resistance, and high adhesion. The present disclosure also describes a rechargeable battery which includes the separator for a rechargeable battery. One aspect of the present disclosure includes a separator for a rechargeable battery. 1.The separator for a rechargeable battery includes one or more fibrous layers, wherein at least one of the fibrous layers includes a fiber network of fibers containing a first copolymer, and at least one of the fibrous layers includes a polyimide-based fiber, or a core-shell fiber containing a polyimide-based resin. The first copolymer includes a copolymer including a first structural unit including a unit derived from an aromatic based unsaturated monomer; a second structural unit derived from a (meth)acryl-based monomer containing an alkyl group with 4 or more carbon atoms in the main chain in an ester moiety; and a third structural unit derived from a monomer containing a sulfonic acid group. Herein, the first structural unit, the second structural unit, and the third structural unit are respectively included at a range of from about 5 mol% to about 80 mol%, a range of from about 10 mol% to about 60 mol%, and a range of from about 5 mol% to about 80 mol% with respect to 100 mol% of the copolymer.2. The separator of aspect 1, wherein the first copolymer comprises an adhesive binder.3. The separator of aspect 1 or 2, wherein the first copolymer has a glass transition temperature in a range of from about 60 °C to about 80 °C.4. The separator of any one of aspects 1 to 3, wherein the sum of the contents of the first structural unit, the second structural unit, and the third structural unit in the copolymer is about 95 mol% or more.5. The separator of any one of aspects 1 to 4, wherein a unit derived from the aromatic based unsaturated monomer is represented by Chemical Formula 1, in Chemical Formula 1, R1 and R2 each independently comprises hydrogen or a substituted or unsubstituted C1 to C5 alkyl group, andAr comprises a substituted or unsubstituted, monocyclic or polycyclic C6 to C20 aryl group),the second structural unit is represented by Chemical Formula 4, in Chemical Formula 4,R7 and R8 each independently comprises hydrogen or a methyl group,L2 comprises a substituted or unsubstituted, linear or branched C4 to C30 alkyl group), andthe third structural unit is represented by any one of Chemical Formulas 5, 6, and 7: in Chemical Formulas 5 to 7,R9, R10, R11, R12, R13, and R14 each independently comprises hydrogen or a C1 to C3 alkyl group,L3, L5, and L7 each independently comprises -C(=O)-, -C(=O)O-, -OC(=O)-, -O-, or -C(=O)NH-,L4, L6, and L8 each independently comprises a substituted or unsubstituted C1 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, anda, b, c, d, e, and f are each independently an integer in a range of 0 to 2, andin Chemical Formula 6,M comprises an alkali metal.6. The separator of any one of aspects 1 to 5, wherein the first structural unit further comprises a unit derived from a (meth)acryl-based monomer containing an alkyl group having 1 to 3 carbon atoms in the main chain in an ester moiety.7. The separator of aspect 6, wherein the unit derived from the (meth)acryl-based monomer is a unit represented by Chemical Formula 3: in Chemical Formula 3, R5 and R6 each independently comprises hydrogen or a methyl group,L1 comprises a substituted or unsubstituted, linear or branched C1 to C3 alkyl group.8. The separator of any one of aspects 1 to 7, wherein the separator comprises a multi-layer separator including the fibrous layer; and/or wherein the multi-layer separator comprises one or more, or two or more, fibrous layers including a fiber network of fibers containing the first copolymer.9. The separator of a