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CN-121986411-A - Separator for lithium secondary battery and lithium secondary battery including the same

CN121986411ACN 121986411 ACN121986411 ACN 121986411ACN-121986411-A

Abstract

A separator for a lithium secondary battery includes a porous polymer substrate, and a porous coating layer disposed on at least one surface of the porous polymer substrate, the porous coating layer including inorganic particles and a binder polymer, wherein the inorganic particles include surface-modified calcium carbonate (CaCO 3 ) including a first surface-modified calcium carbonate, a second surface-modified calcium carbonate, or a combination thereof, the first surface-modified calcium carbonate including a first calcium carbonate and a fatty acid-derived functional group chemically bonded to a surface of the first calcium carbonate, and the second surface-modified calcium carbonate including a second calcium carbonate and an organosilane-derived functional group chemically bonded to a surface of the second calcium carbonate.

Inventors

  • Jin Youpei
  • LI BINGKUI
  • LI CHENGXUAN
  • Jia Guilun

Assignees

  • 株式会社LG新能源

Dates

Publication Date
20260505
Application Date
20250530
Priority Date
20240603

Claims (11)

  1. 1. A separator for a lithium secondary battery, the separator comprising: A porous polymer substrate, and A porous coating layer formed on at least one surface of the porous polymer substrate, the porous coating layer including inorganic particles and a binder polymer, Wherein the inorganic particles comprise surface modified calcium carbonate (CaCO 3 ), The surface-modified calcium carbonate comprises a first surface-modified calcium carbonate, a second surface-modified calcium carbonate, or a combination thereof, The first surface-modified calcium carbonate comprises a first calcium carbonate and a fatty acid-derived functional group chemically bound to the surface of the first calcium carbonate, and The second surface-modified calcium carbonate includes a second calcium carbonate and an organosilane-derived functional group chemically bonded to a surface of the second calcium carbonate.
  2. 2. The separator of claim 1, wherein the surface modified calcium carbonate comprises surface modified precipitated calcium carbonate.
  3. 3. The separator of claim 1, wherein the surface modified calcium carbonate has a D 50 (average particle size) in the range of about 0.1 μιη to 2.0 μιη.
  4. 4. The separator of claim 1, wherein the surface modified calcium carbonate has an aspect ratio in the range of about 1.0 to 1.5.
  5. 5. The separator of claim 1 wherein the fatty acid derived functional group is derived from a fatty acid having from 10 to 24 carbon atoms or a salt thereof.
  6. 6. The separator of claim 1 wherein the organosilane-derived functional group is derived from an organosilane selected from the group consisting of vinyltrimethoxysilane (vinyltrimethoxysilane), vinyltriethoxysilane (vinyltriethoxysilane), vinyltris (β -methoxyethoxy) silane (vinyltris (β -methoxyethoxy) silane), β - (3, 4-epoxycyclohexyl) ethyltrimethoxysilane (β - (3, 4-epoxycyclohexyl) ethyltrimethoxysilane), gamma- (2-aminoethyl) aminopropyl trimethoxysilane (gamma- (2-aminoethyl) aminopropyltrimethoxysilane), gamma-glycidoxypropyl trimethoxysilane (gamma-glycidoxypropyltrimethoxysilane), gamma-glycidoxypropyl trimethyldiethoxysilane (gamma-glycidoxypropyltrimethyldiethoxysilane), gamma-glycidoxypropyl triethoxysilane (gamma-glycidoxypropyltriethoxysilane), Gamma-methacryloxypropyl methyl dimethoxy silane (gamma-methacryloxypropylmethyldimethoxysilane), gamma-methacryloxypropyl trimethoxy silane (gamma-methacryloxypropyltrimethoxysilane), gamma-methacryloxypropyl methyl diethoxy silane (gamma-methacryloxypropylmethyldiethoxysilane), gamma-methacryloxypropyl triethoxy silane (gamma-methacryloxypropyltriethoxysilane), N-beta (aminoethyl) -gamma-aminopropyl methyl dimethoxy silane (N-beta (aminoethyl) -gamma-aminopropylmethyldimethoxysilane), N-beta (aminoethyl) -gamma-aminopropyl trimethoxy silane (N-beta (aminoethyl) -gamma-aminopropyltrimethoxysilane), N-beta (aminoethyl) -gamma-aminopropyl triethoxy silane (N-beta (aminoethyl) -gamma-aminopropyltriethoxysilane), and, 3-aminopropyl trimethoxysilane (3-aminopropyltrimethoxysilane), 3-aminopropyl triethoxysilane (3-aminopropyltriethoxysilane), N-phenyl-gamma-aminopropyl trimethoxysilane (N-phenyl-gamma-aminopropyltrimethoxysilane), gamma-chloropropyl trimethoxysilane (gamma-chloropropyltrimethoxysilane), gamma-mercaptopropyl trimethoxysilane (gamma-mercaptopropyltrimethoxysilane), Bis- [3- (triethoxysilyl) propyl ] -tetrasulfide (bis- [3- (triethoxysilyl) propyl ] -tetrasulfide) (TESPT), bis- [3- (triethoxysilyl) propyl ] -disulfide (bis- [3- (triethoxysilyl) propyl ] -disulfide) or combinations thereof.
  7. 7. The separator of claim 1, wherein the inorganic particles further comprise Pb(Zr、Ti)O 3 （PZT）、Pb 1- x La x Zr 1-y Ti y O 3 （PLZT）、Pb(Mg 3 Nb 2/3 )O 3 -PbTiO 3 （PMN-PT）、 hafnium （HfO 2 ）、SrTiO 3 、SnO 2 、CeO 2 、MgO、NiO、CaO、ZnO、ZrO 2 、Y 2 O 3 、Al 2 O 3 、TiO 2 、SiC、AlO(OH)、Al 2 O 3 ·H 2 O、 lithium phosphate (Li 3 PO 4 ), lithium titanium phosphate (Li x Ti y (PO 4 ) 3 , 0< x < 2), 0< y < 3), lithium aluminum titanium phosphate （Li x Al y Ti z (PO 4 ) 3 ,0<x<2、0<y<1、0<z<3）、(LiAlTiP) x O y base glass (0 < x <4, 0< y < 13) such as 14Li 2 O-9Al 2 O 3 -38TiO 2 -39P 2 O 5 , lithium lanthanum titanate (Li x La y TiO 3 , 0< x < 2), 0< y < 3), lithium germanium thiophosphate (Li x Ge y P z S w , 0< x <4, 0< y <1, 0< z <1, 0< w < 5) such as Li 3.25 Ge 0.25 P 0.75 S 4 , lithium nitride (Li x N y , 0< x < 4), 0< y < 2) such as Li 3 N、SiS 2 -based glass (Li x Si y S z , 0< x <3, 0< y <2, 0< z < 4) such as Li 3 PO 4 -Li 2 S-SiS 2 、P 2 S 5 -based glass (Li x P y S z , 0< x < 3), 0< y <3, 0< z < 7) such as LiI-Li 2 S-P 2 S 5 , and mixtures thereof.
  8. 8. The separator of claim 1, wherein the binder polymer comprises poly (methyl methacrylate) (poly (methyl methacrylate)), poly (butyl acrylate) (poly (butyl acrylate)), polyacrylonitrile (polyacrylonitrile), polyvinylpyrrolidone (polyvinylpyrrolidone), polyvinyl acetate (polyvinyl acetate), polyethylene-vinyl acetate copolymer (polyethylene-co-VINYL ACETATE), polyethylene oxide (polyethylene oxide), polyarylate (polyacrylate), cellulose acetate (cellulose acetate), cellulose acetate butyrate (cellulose acetate butyrate), cellulose acetate propionate (cellulose acetate propionate), cyanoethyl pullulan (cyanoethyl pullulan), cyanoethyl polyvinyl alcohol (cyanoethyl polyvinyl alcohol), cyanoethyl cellulose (cyanoethyl cellulose), cyanoethyl sucrose (cyanoethyl sucrose), pullulan (pullulan), and carboxymethyl cellulose (carboxyl methyl cellulose), or a mixture of two or more thereof.
  9. 9. The separator of claim 1, wherein the surface modified calcium carbonate has a sedimentation rate (%/hr) of-2.5 or greater as determined by a turbacan analysis.
  10. 10. The separator of claim 1, wherein the content of fatty acid derived functional groups is in the range of about 0.5 to 5 parts by weight, based on 100 parts by weight of the first surface-modified calcium carbonate, and The organosilane-derived functional group is present in an amount in the range of about 0.5 to 5 parts by weight based on 100 parts by weight of the second surface-modified calcium carbonate.
  11. 11. A lithium secondary battery comprising: a positive electrode; Negative electrode, and The separator of claim 1.

Description

Separator for lithium secondary battery and lithium secondary battery including the same Technical Field The present disclosure relates to a separator for a lithium secondary battery and a lithium secondary battery including the same. The present application is based on and claims priority of korean patent application No. 10-2024-0074043 filed on 6/3 of 2024 to korean intellectual property office, the disclosure of which is incorporated herein by reference in its entirety. Background Lithium secondary batteries are widely used not only as power sources for portable electronic devices such as notebook computers, mobile phones, digital still cameras, and video cameras, but also as power sources for electric vehicles. Since lithium secondary batteries are being widely used in various fields, concerns about the safety of lithium secondary batteries have arisen. For example, as lithium secondary batteries develop to high capacity and high power, the probability of abnormal temperature rise during charge and discharge processes increases, which may lead to a so-called thermal runaway phenomenon in which flames burst at high temperatures, and if thermal runaway occurs, the fire may not be easily extinguished. Therefore, the safety problem is considered to be one of the more important problems to be solved in a high-capacity, high-output lithium secondary battery. Disclosure of Invention Technical problem The present disclosure provides a separator for a lithium secondary battery, the separator including a porous coating layer including surface-modified calcium carbonate, which exhibits excellent dispersibility and wettability even without including a dispersing agent or a wetting agent. The present disclosure provides a separator for a lithium secondary battery that includes surface-modified calcium carbonate and is capable of preventing or delaying heat transfer during a thermal runaway event. The present disclosure provides a separator for a lithium secondary battery, which has low surface roughness due to excellent dispersibility of surface-modified calcium carbonate. The present disclosure provides a lithium secondary battery having excellent resistance characteristics by excluding a dispersant and a wetting agent from a porous coating layer. Technical proposal According to one aspect of the present disclosure, there are provided a separator for a lithium secondary battery and a lithium secondary battery including the same as described in the following embodiments. According to a first embodiment, a separator for a lithium secondary battery includes a porous polymer substrate, and a porous coating layer formed on at least one surface of the porous polymer substrate. The porous coating includes inorganic particles and a binder polymer, wherein the inorganic particles include surface modified calcium carbonate (CaCO 3). The surface-modified calcium carbonate comprises a first surface-modified calcium carbonate, a second surface-modified calcium carbonate, or a combination thereof. The first surface-modified calcium carbonate includes a first calcium carbonate and fatty acid-derived functional groups chemically bonded to a surface of the first calcium carbonate, and the second surface-modified calcium carbonate includes a second calcium carbonate and organosilane-derived functional groups chemically bonded to a surface of the second calcium carbonate. According to a second embodiment, the surface-modified calcium carbonate in the first embodiment may comprise surface-modified precipitated calcium carbonate. According to the third embodiment, D 50 (average particle diameter) of the surface-modified calcium carbonate in the first or second embodiment may be in the range of about 0.1 μm to 2.0 μm. According to a fourth embodiment, the surface-modified calcium carbonate in any one of the first to third embodiments may have an aspect ratio in the range of about 1.0 to 1.5. According to a fifth embodiment, the fatty acid-derived functional group in any of the first to fourth embodiments may be derived from a fatty acid having 10 to 24 carbon atoms or a salt thereof. According to a sixth embodiment, the organosilane-derived functional group of any of the first to fifth embodiments may be derived from an organosilane selected from the group consisting of vinyltrimethoxysilane (vinyltrimethoxysilane), vinyltriethoxysilane (vinyltriethoxysilane), vinyltris (β -methoxyethoxy) silane (vinyltris (β -methoxyethoxy) silane), β - (3, 4-epoxycyclohexyl) ethyltrimethoxysilane (β - (3, 4-epoxycyclohexyl) ethyltrimethoxysilane), gamma- (2-aminoethyl) aminopropyl trimethoxysilane (gamma- (2-aminoethyl) aminopropyltrimethoxysilane), gamma-glycidoxypropyl trimethoxysilane (gamma-glycidoxypropyltrimethoxysilane), gamma-glycidoxypropyl trimethyldiethoxysilane (gamma-glycidoxypropyltrimethyldiethoxysilane), gamma-glycidoxypropyl triethoxysilane (gamma-glycidoxypropyltriethoxysilane), Gamma-methacryloxypropyl methyl dimethoxy silane (g