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EP-4521540-B1 - SOLID ELECTROLYTE SEPARATOR, ALL-SOLID SECONDARY BATTERY INCLUDING THE SAME, AND METHOD OF MANUFACTURING THE SOLID ELECTROLYTE SEPARATOR

EP4521540B1EP 4521540 B1EP4521540 B1EP 4521540B1EP-4521540-B1

Inventors

  • PARK, TAEHYUN
  • SON, INHYUK
  • JO, SungNim
  • SHIM, Kyueun
  • Lee, Jieun
  • LIM, HYUNGSUB

Dates

Publication Date
20260513
Application Date
20240618

Claims (15)

  1. A solid electrolyte separator comprising: a composite of Li 2 S and a lithium salt; and a sulfide-based solid electrolyte, wherein the composite of Li 2 S and the lithium salt is represented by Li 2 S-Li a X b where 1≤a≤5 and 1≤b≤5, and X is I, Br, Cl, F, H, O, Se, Te, N, P, As, Sb, Al, B, OCI, PF 6 , BF 4 , SbF 6 , AsF 6 , ClO 4 , AlO 2 , AlCl 4 , NO 3 , CO 3 , BH 4 , SO 4 , BO 3 , PO 4 , NCI, NCl 2 , BN 2 , or a combination thereof.
  2. The solid electrolyte separator as claimed in claim 1, wherein the lithium salt comprises a binary compound and/or a ternary compound, wherein the binary compound comprises Lil, LiBr, LiCl, LiF, LiH, Li 2 O, Li 2 Se, Li 2 Te, Li 3 N, Li 3 P, Li 3 As, Li 3 Sb, Li 3 Al 2 , LiB 3 , or a combination thereof, and the ternary compound comprises Li 3 OCl, LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiClO 4 , LiAlO 2 , LiAlCl 4 , LiNO 3 , Li 2 CO 3 , LiBH 4 , Li 2 SO 4 , Li 3 BO 3 , Li 3 PO 4 , Li 4 NCl, Li 5 NCl 2 , Li 3 BN 2 , or a combination thereof.
  3. The solid electrolyte separator as claimed in claim 1, wherein the composite comprises a solid solution of Li 2 S and the lithium salt, and a size of Li 2 S crystallites obtained from an XRD spectrum of the composite is 20 nm or less and/or in the composite, an amount of the Li 2 S is greater than an amount of the lithium salt, and a molar ratio of the Li 2 S to the lithium salt is in a range of about 51:49 to about 95:5.
  4. The solid electrolyte separator as claimed in any of the claims 1 to 3, wherein the composite has a smaller Mohs hardness than the lithium salt, wherein the Mohs hardness of the composite is less than 2.
  5. The solid electrolyte separator as claimed in any of the claims 1 to 4, wherein an amount of the composite is in a range of about 0.1 wt% to about 20 wt% with respect to a total weight of the composite and the sulfide-based solid electrolyte.
  6. The solid electrolyte separator as claimed in any of the claims 1 to 5, wherein the solid electrolyte separator comprises composite particles and a plurality of sulfide-based solid electrolyte particles, wherein the sizes of said particles are measured with the method as indicated in the description, wherein the composite particles have a smaller size than the sulfide-based solid electrolyte particles, and the composite particles are provided in pores between the plurality of sulfide-based solid electrolyte particles, whereby preferably the solid electrolyte separator has a porosity of 8% or less and/or the sulfide-based solid electrolyte particles have a size of about 1 µm to about 10 µm, the composite particles have a size of 2 µm or less, and a ratio of the size of the sulfide-based solid electrolyte particles to the size of the composite particles is in a range of about 2:1 to about 200:1.
  7. The solid electrolyte separator as claimed in in any of the claims 1 to 6, wherein the sulfide-based solid electrolyte comprises at least one selected from Li 2 S-P 2 S 5 , Li 2 S-P 2 S 5 -LiX where X is a halogen element, Li 2 S-P 2 S 5 -Li 2 O, Li 2 S-P 2 S 5 -Li 2 O-LiI, Li 2 S-SiS 2 , Li 2 S-SiS 2 -LiI, Li 2 S-SiS 2 -LiBr, Li 2 S-SiS 2 -LiCl, Li 2 S-SiS 2 -B 2 S 3 -LiI, Li 2 S-SiS 2 -P 2 S 5 -LiI, Li 2 S-B 2 S 3 , Li 2 S-P 2 S S -Z m S n where m and n are positive numbers and Z is Ge, Zn, or Ga, Li 2 S-GeS 2 , Li 2 S-SiS 2 -Li 3 PO 4 , Li 2 S-SiS 2 -Li p MO q where p and q are positive numbers and M is one selected from P, Si, Ge, B, Al, Ga, and In, Li 7-x PS 6-x Cl x where 0≤x≤2, Li 7-x PS 6-x Br x where 0≤x≤2, and Li 7-x PS 6-x I x where 0≤x≤2, and the sulfide-based solid electrolyte comprises an argyrodite-type solid electrolyte, wherein the argyrodite-type solid electrolyte comprises at least one selected from Li 6 PS 5 Cl, Li 6 PS 5 Br, and Li 6 PS 5 I, and the argyrodite-type solid electrolyte has a density of about 1.5 g/cc to about 2.0 g/cc.
  8. The solid electrolyte separator as claimed in any of the claims 1 to 7, wherein the solid electrolyte separator further comprises a binder, the solid electrolyte separator is free of a carbon-based conductive material, the solid electrolyte separator is a self-standing film, and the solid electrolyte separator has a curvature greater than 0.
  9. An all-solid secondary battery (1) comprising: a cathode (10); an anode (20); and a solid electrolyte layer (30) between the cathode (10) and the anode (20), wherein the solid electrolyte layer (30) comprises the solid electrolyte separator according to claim 1.
  10. The all-solid secondary battery (1) as claimed in claim 9, wherein the cathode (10) comprises a cathode active material, wherein the cathode active material comprises a sulfide-based cathode active material, an oxide-based cathode active material, or a combination thereof, wherein the sulfide-based cathode active material comprises nickel sulfide, copper sulfide, Li 2 S, a Li 2 S-containing composite, or a combination thereof, and the oxide-based cathode active material comprises a lithium transition metal oxide, a metal oxide, or a combination thereof, the lithium transition metal oxide comprising lithium cobalt oxide, lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium manganate, lithium iron phosphate, or a combination thereof, and the metal oxide comprising iron oxide, vanadium oxide, or a combination thereof.
  11. The all-solid secondary battery (1) as claimed in claim 9 or 10, wherein the anode (20) comprises an anode current collector (21) and a first anode active material layer (22) on one surface of the anode current collector (21), whereby preferably the first anode active material layer (22) is a metal layer, the metal layer comprising lithium and/or a lithium alloy, or the first anode active material layer (22) comprises an anode active material and a binder, the anode active material having a particle form and an average particle diameter of 4 µm or less, wherein said average particle diameter refers to the cumulative volume of 50% calculated from particles having the smallest particle size in the particle size distribution measured by a laser diffraction method; whereby preferably the anode active material comprises at least one selected from a carbon-based anode active material and a metal and/or metalloid anode active material, wherein the carbon-based anode active material comprises amorphous carbon, crystalline carbon, porous carbon, or a combination thereof, and the metal and/or metalloid anode active material comprises gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), zinc (Zn), or a combination thereof, and the anode active material comprises a mixture of primary particles consisting of amorphous carbon and secondary particles consisting of a metal and/or a metalloid, wherein an amount of the secondary particles is in a range of about 1 wt% to about 60 wt% with respect to a total weight of the mixture.
  12. The all-solid secondary battery (1) as claimed in any of the claims 9 to 11, further comprising a second anode active material layer (24) between the anode current collector (21) and the first anode active material layer (22) and/or between the anode current collector (21) and the solid electrolyte layer (30), wherein the second anode active material layer (24) is a metal layer, the metal layer comprising lithium and/or a lithium alloy.
  13. The all-solid secondary battery (1) as claimed in any of the claims 9 to 12 wherein the solid electrolyte layer (30) further comprises a solid electrolyte, a gel electrolyte, or a combination thereof, wherein the solid electrolyte comprises an oxide-based solid electrolyte, a polymer solid electrolyte, or a combination thereof, and the gel electrolyte comprises a polymer gel electrolyte.
  14. The all-solid secondary battery (1) as claimed in any of the claims 9 to 13, wherein the cathode (10) comprises a cathode current collector (11), and the anode (20) comprises an anode current collector (21), wherein at least one selected from the cathode current collector (11) and the anode current collector (21) comprises a base film and a metal layer on one or both surfaces of the base film, wherein the base film comprises a polymer, the polymer comprising polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or a combination thereof, and the metal layer comprises indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), and/or an alloy thereof.
  15. A method of manufacturing a solid electrolyte separator, the method comprising: providing a composite of Li 2 S and a lithium salt; providing a sulfide-based solid electrolyte; mixing together the sulfide-based solid electrolyte and the composite of Li 2 S and the lithium salt to prepare a mixture; and molding the mixture to prepare a solid electrolyte separator, wherein the composite of Li 2 S and the lithium salt is represented by Li 2 S-Li a X b where 1≤a≤5 and 1≤b≤5, and X is I, Br, Cl, F, H, O, Se, Te, N, P, As, Sb, Al, B, OCI, PF 6 , BF 4 , SbF 6 , AsF 6 , ClO 4 , AlO 2 , AlCl 4 , NO 3 , CO 3 , BH 4 , SO 4 , BO 3 , PO 4 , NCI, NCl 2 , BN 2 , or a combination thereof.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application claims priority to and the benefit of Korean Patent Application No. 10-2023-0119611, filed on September 8, 2023, in the Korean Intellectual Property Office. BACKGROUND 1. Field One or more embodiments of the present disclosure relate to a solid electrolyte separator, an all-solid secondary battery including the same, and a method of manufacturing the solid electrolyte separator. 2. Description of the Related Art Recently, in line with industrial progress, the development of batteries having high energy density and safety has been actively conducted. For example, lithium batteries are used in various applications, including information devices, communication devices, vehicles, and/or the like. Vehicles can have an effect on life, and thus, safety of batteries is an important consideration. Lithium batteries employing liquid electrolytes can increase the risk of fire and/or explosion if a short circuit occurs. All-solid secondary batteries that employ solid electrolytes instead of liquid electrolytes have been proposed. Solid electrolytes are less likely to ignite than liquid electrolytes. By employing a solid electrolyte in an all-solid secondary battery instead of a liquid electrolyte, the risk and/of fire or explosion can be reduced. All-solid batteries may provide improved safety. FUDONGHAN ET AL: "Suppressing Li Dendrite Formation in Li 2S-P2S5 Solid Electrolyte by Lil Incorporation", ADVANCED ENERGY MATERIALS, vol. 8, no. 18, page 1703644 discloses a solid electrolyte separator comprising (100-x)(0.75Li2S - 0.25P2S5)-x Lil (x=0, 10, 20, 30, and 40) solid electrolytes synthesized using high-energy mechanical milling of Li2S, P2S5 and Lil as starting materials. Furthermore, YU CHUANG ET AL: "Superionic conductivity in lithium argyrodite solid-state electrolyte by controlled CI-doping", NANO ENERGY, vol. 69, 1 March 2020 (2020-03-01), page 104396, discloses a solid electrolyte separator comprising Li 7-xPS6-xClx (x = 1.1, ...,1.8) solid electrolytes synthesized using high-energy mechanical milling of Li2S, P2S5 and LiCl as starting materials followed by annealing. Additionally, TAKAHASHI MASAKUNI ET AL: "Investigation of the Suppression of Dendritic Lithium Growth with a Lithium-Iodide-Containing Solid Electrolyte", CHEMISTRY OF MATERIALS, vol. 33, no. 13, pages 4907-4914, discloses a solid electrolyte separator comprising (100-x)Li 3PS4-x-x Lil (x=0, 10, ... 60) solid electrolytes synthesized using high-energy mechanical milling of Li2S, P2S5 and Lil as starting materials followed by annealing. FUJITA YUSHI ET AL: "Li 2S-Lil Solid Solutions with Ionic Conductive Domains for Enhanced All-Solid-State Li/S Batteries", ACS APPLIED ENERGY MATERIALS, vol. 5, no. 8, 2 August 2022 (2022-08-02), pages 9429-9436 discloses Li2S-Lil-based composites, either as such or with additional carbon conductive as cathode active material on a conventional Li3PS4 glass powder separator. TAKASHI HAKARI ET AL: "Li 2S-Based Solid Solutions as Positive Electrodes with Full Utilization and Superlong Cycle Life in All-Solid-State Li/S Batteries", ADVANCED SUSTAINABLE SYSTEMS, WILEY, US, vol. 1, no. 6, page 1700017, discloses Li2S-LiX (X=I, Cl, Br) composites as cathode materials. SUMMARY One or more embodiments of the present disclosure include a solid electrolyte separator having improved durability by including a composite of Li2S and a lithium salt. One or more embodiments include an all-solid secondary battery including the solid electrolyte separator. One or more embodiments include a method of manufacturing the solid electrolyte separator. Additional aspects of embodiments will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the present disclosure. According to one or more embodiments, a solid electrolyte separator includes: a composite of Li2S and a lithium salt, anda sulfide-based solid electrolyte,wherein the composite of Li2S and the lithium salt is represented by Li2S-LiaXb where 1≤a≤5 and 1≤b≤5, andX is I, Br, Cl, F, H, O, Se, Te, N, P, As, Sb, Al, B, OCI, PF6, BF4, SbF6, AsF6, ClO4, AlO2, AlCl4, NO3, CO3, BH4, SO4, BO3, PO4, NCI, NCl2, BN2, or a combination thereof. According to one or more embodiments, an all-solid secondary battery includes: a cathode, an anode, and a solid electrolyte layer between the cathode and the anode,wherein the solid electrolyte layer includes the above-described solid electrolyte separator. According to one or more embodiments, a method of manufacturing the sold electrolyte separator includes: providing a composite of Li2S and a lithium salt,providing a sulfide-based solid electrolyte,mixing together the sulfide-based solid electrolyte and the composite of Li2S and the lithium salt to prepare a mixture, andmolding the mixture to prepare a solid electrolyte separator,wherein the composite of Li2S and the lithium