Separator for electrochemical device, and electrochemical device comprising same

Patent metadata

Field	Value
Publication number	US-2024429560-A1
Application number	US-202318696156-A
Country	US
Kind code	A1
Filing date	Aug 29, 2023
Priority date	Aug 29, 2022
Publication date	Dec 26, 2024
Grant date	—

Abstract

Disclosed is a separator for an electrochemical device including a lithium manganese-based active material, which includes a porous polymer substrate; a first porous coating layer, which includes a first inorganic particle and a second inorganic particle having a larger specific surface area than the first inorganic particle and which is present on a first surface of the porous polymer substrate; and a second coating layer present on a second surface of the porous polymer substrate, wherein the second inorganic particle includes sulfonic acid groups on a surface thereof, and in some of the sulfonic acid groups, hydrogen cations are substituted with lithium cations.

First claim

1 . A separator for an electrochemical device comprising a lithium manganese-based active material, wherein the separator comprises:
a porous polymer substrate having a first surface and a second surface; a first porous coating layer on the first surface of the porous polymer substrate, which first porous coating layer comprises a first inorganic particle and a second inorganic particle, wherein the second inorganic particle has an average specific surface area larger than an average specific surface area of the first inorganic particle; and a second coating layer on the second surface of the porous polymer substrate, wherein the second inorganic particle comprises sulfonic acid groups on a surface thereof, in which in some of the sulfonic acid groups, hydrogen cations are substituted with lithium cations.

2 . The separator of claim 1 , wherein the first porous coating layer comprises the first inorganic particle and the second inorganic particle in a weight ratio of 2:8 to 3:7.

3 . The separator of claim 1 , wherein the second inorganic particle is a mesoporous inorganic particle comprising pores with an average diameter of 1.5 nm to 50 nm.

4 . The separator of claim 3 , wherein the first inorganic particle is different from the second inorganic particle and the first inorganic particle does not comprise pores.

5 . The separator of claim 1 , wherein the sulfonic acid group is one or more selected from the group consisting of methane sulfonic acid, ethane sulfonic acid, trifluoromethane sulfonic acid, benzene sulfonic acid, p-toluene sulfonic acid, naphthalene sulfonic acid, phenylbenzimidazole sulfonic acid, and 2-acrylamido-2-methylpropane sulfonic acid.

6 . The separator of claim 1 , wherein the first inorganic particle is one or more selected from the group consisting of Li 3 PO 4 , Li x Ti y (PO 4 ) 3 (0<x<2, 0<y<3), Li x Al y Ti z (PO 4 ) 3 (0<x<2, 0<y<1, 0<z<3), Li x La y TiO 3 (0<x<2, 0<y<3), Li x Ge y P z S w (0<x<4, 0<y<1, 0<z<1, 0<w<5), Li x N y (0<x<4, 0<y<2), Li x Si y S z (0<x<3, 0<y<2, 0<z<4), Li x P y S z (0<x<3, 0<y<3, 0<z<7), Li 7 La 3 Zr 2 O 12 , BaTiO 3 , BaSO 4 , Pb(Zr,Ti)O 3 (PZT), Pb 1−x La x Zr 1−y Ti y O 3 (PLZT, 0<x<1, 0<y<1), Pb(Mg 1/3 Nb 2/3 )O 3 —PbTiO 3 (PMN-PT), HfO 2, Sb 2 O 3 , Sb 2 O 4 , Sb 2 O 5 , SrTiO 3 , SnO 2 , CeO 2 , MgO, Mg(OH) 2 , NiO, CaO, ZnO, Zn 2 SnO 4 , ZnSnO 3 , ZnSn(OH) 6 , ZrO 2 , Y 2 O 3 , SiO 2 , Al 2 O 3 , AlOOH, Al(OH) 3 , SiC, TiO 2 , H 3 BO 3 , and HBO 2 .

7 . The separator of claim 1 , wherein the first porous coating layer further comprises a water-based polymer binder, wherein the water-based polymer binder forms an interstitial volume being formed by gaps between inorganic particles by bonding first inorganic particles with one another, second inorganic particles with one another, and first inorganic particles with second inorganic particles.

8 . The separator of claim 7 , wherein the water-based polymer binder is one or more selected from the group consisting of an acrylic-based polymer, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, an ethylene vinyl acetate copolymer, a polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethylpolyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxylmethylcellulose, an acrylonitrile-styrene-butadiene copolymer, and polyimide.

9 . The separator of claim 1 , wherein the first porous coating layer faces a negative electrode of the electrochemical device.

10 . The separator of claim 9 , wherein the second coating layer comprises the first inorganic particle but does not comprise the second inorganic particle.

11 . The separator of claim 1 , wherein the lithium manganese-based active material is one or more positive electrode active material selected from the group consisting of Li 1+x Mn 2−x O 4 (0≤x≤0.33), LiMnO 3 , LiMn 2 O 3 , LiMnO 2 , LiNi 1−x Mn x O 2 (0.01≤x≤0.3), LiMn 2−x M x O 2 (M═Co, Ni, Fe, Cr, Zn, or Ta, 0.01≤x≤0.1), Li 2 Mn 3 MO 8 (M═Fe, Co, Ni, Cu, or Zn), LiNi x Mn 2−x O 4 (0<x<0.5), and LiMn 2 O 4 .

12 . The separator of claim 1 , wherein the average specific surface area of the first inorganic particles and the second inorganic particles included in the porous coating layer is 500 m 2 /g to 700 m 2 /g.

13 . The separator of claim 1 , wherein the porous coating layer has a thickness of 1 μm to 6 μm.

14 . The separator of claim 1 , wherein the separator has an adsorption rate of 20% to 50%. to manganese ions being eluted from a positive electrode comprising the lithium manganese-based active material.

15 . An electrochemical device comprising:
a positive electrode, a negative electrode, and a separator between the positive electrode and the negative electrode, wherein the separator is the separator for the electrochemical device according to claim 1 .

16 . The electrochemical device of claim 15 , wherein the first porous coating layer of the separator faces the negative electrode.

17 . The electrochemical device of claim 15 , wherein the positive electrode comprises a lithium manganese-based active material.

18 . The electrochemical device of claim 17 , wherein the lithium manganese-based active material is one or more positive electrode active material selected from the group consisting of Li 1+x Mn 2−x O 4 (0≤x≤0.33), LiMnO 3 , LiMn 2 O 3 , LiMnO 2 , LiNi 1−x Mn x O 2 (0.01≤x≤0.3), LiMn 2−x M x O 2 (M═Co, Ni, Fe, Cr, Zn, or Ta, 0.01≤x≤0.1), Li 2 Mn 3 MO 8 (M═Fe, Co, Ni, Cu, or Zn), LiNi x Mn 2−x O 4 (0<x<0.5), and LiMn 2 O 4 .

19 . The separator of claim 12 , wherein the average specific surface area of the first inorganic particles and the second inorganic particles included in the porous coating layer is 500 m 2 /g to 700 m 2 /g.

Assignees

• Lg Energy Solution Ltd

Inventors

• Yoon Yeo Ju
• Kim Seong Jun
• Jeong So Mi

Classifications

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M50/403

  Manufacturing processes of separators, membranes or diaphragms · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M50/431

  Inorganic material · CPC title