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EP-4742357-A1 - ALL-SOLID-STATE BATTERY AND METHOD FOR MANUFACTURING SAME

EP4742357A1EP 4742357 A1EP4742357 A1EP 4742357A1EP-4742357-A1

Abstract

The present disclosure relates to an all-solid-state battery and can provide an all-solid-state battery comprising a cathode, a solid electrolyte layer, an anodeless coating layer, and an anode current collector, and a manufacturing method therefor, wherein the anodeless coating layer includes amorphous carbon and silver nanoparticles, and when the anode-free coating layer is divided in the thickness direction into two equal parts, referred to as a first region and a second region in order from the side closer to the anode current collector, the ratio (C2/C1) of the silver nanoparticle content (C2) in the second region to the silver nanoparticle content (C1) in the first region falls within the range of 0.4 to 2 after charging/discharging. This configuration ensures excellent reactivity between silver nanoparticles and lithium ions, and high lithium ion conductivity. Even after charge and discharge cycles, the distribution characteristics of silver nanoparticles remain excellent, contributing to the uniformity of internal resistance in the battery and effectively regulating lithium dendrite growth. Accordingly, the all-solid-state battery of the present invention has an excellent capacity retention rate, particularly, an excellent capacity retention rate at a high rate, and also exhibits excellent lifespan characteristics.

Inventors

  • PARK, MIHUI
  • LEE, HYUNJEONG
  • LEE, HYE JIN
  • JUNG, YI JIN
  • SONG, MIN SANG
  • YOM, Jeeho
  • LEE, DONG CHAN
  • CHOI, RAN

Assignees

  • LG Energy Solution, Ltd.

Dates

Publication Date
20260513
Application Date
20250210

Claims (15)

  1. An all-solid-state battery using lithium or a lithium alloy as a negative electrode active material, the all-solid-state battery comprising a positive electrode, a solid electrolyte layer, an anode-free coating layer and a negative electrode current collector, wherein the anode-free coating layer comprises amorphous carbon and silver nanoparticles, and when the anode-free coating layer is divided into two parts in a thickness direction and sequentially referred to as a first section and a second section starting from a section close to the negative electrode collector, a ratio (C 2 /C 1 ) of the content of the silver nanoparticles (C 2 ) comprised in the second section to the content of the silver nanoparticles (C 1 ) comprised in the first section after charge and discharge is within a range of 0.4 to 2.
  2. The all-solid-state battery according to claim 1, wherein, when the anode-free coating layer is divided into three parts in the thickness direction and sequentially referred to as a first section, a second section, and a third section from a section close to the negative electrode collector, a ratio ((C 2 '+C 3 ')/C 1 ') of the sum (C 2 '+C 3 ') of the contents of the silver nanoparticles comprised in the second section and the third section to the content (C 1 ') of the silver nanoparticles comprised in the first section after charge and discharge is within arange of 0.4 to 5.
  3. The all-solid-state battery according to claim 1, wherein the silver nanoparticles are irregularly shaped.
  4. The all-solid-state battery according to claim 1, wherein the maximum value of a difference among (200) plane crystal grain size, (220) plane crystal grain size, and (311) plane crystal grain size of the silver nanoparticles is 1.5 nanometers (nm) or more.
  5. The all-solid-state battery according to claim 1, wherein a Brunauer, Emmett and Teller (BET) specific surface area of the silver nanoparticles is 6 square meters per gram (m 2 /g) or less.
  6. The all-solid-state battery according to claim 1, wherein an average pore size of the silver nanoparticles is 40 nm or more.
  7. The all-solid-state battery according to claim 1, wherein a total pore volume of the silver nanoparticles is 0.065 cubic centimeters per gram (cm 3 /g) or more.
  8. The all-solid-state battery according to claim 1, wherein the amorphous carbon is one or more selected from the group consisting of carbon black, acetylene black, furnace black, Ketjen black and graphene.
  9. The all-solid-state battery according to claim 1, wherein the silver nanoparticles are comprised in a range of 10 parts by weight to 50 parts by weight relative to 100 parts by weight of the amorphous carbon.
  10. The all-solid-state battery according to claim 1, wherein the anode-free coating layer further comprises a binder.
  11. The all-solid-state battery according to claim 1, wherein the solid electrolyte layer comprises a sulfide-based solid electrolyte.
  12. The all-solid-state battery according to claim 11, wherein the sulfide-based solid electrolyte is one or more selected from Li 2 S-P 2 S 5 -Li 2 O, Li 2 S-P 2 S 5 -Li 2 O-LiI, Li 2 S-LiBr-LiI-P 2 S 5 , 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 -Li 3 PO 4 , Li 2 S-SiS 2 -Li p MO q (p and q are positive numbers, and M is one of P, Si, Ge, B, Al, Ga and In), Li 2 S-SiS 2 -P 2 S 5 -LiI, Li 2 S-P 2 S 3 , Li 2 S-P 2 S 5 -LiX (X is a halogen atom), Li 2 S-B 2 S 3 , Li 2 S-P 2 S 5 -Z m S n (m and n are positive numbers), Z is one of Ge, Zn or Ga, Li 2 S-GeS 2 , Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2) and Li 7-x PS 6-x I x (0≤x≤2).
  13. The all-solid-state battery according to claim 1, wherein a 1.0 C-rate (C) capacity retention is 88% or more compared to 0.1 C capacity.
  14. A method for manufacturing an all-solid-state battery using lithium or a lithium alloy as a negative electrode active material,wherein, the method for manufacturing an all-solid-state battery comprises forming an anode-free coating layer on a negative electrode current collector, the forming of the anode-free coating layer on the negative electrode current collector, comprises: applying a composition for forming an anode-free coating layer comprising amorphous carbon and silver nanoparticles; and drying the applied composition for forming an anode-free coating layer to form an anode-free coating layer, and when the anode-free coating layer is divided into two parts in a thickness direction and sequentially referred to as a first section and a second section starting from a section close to the negative electrode current collector, a ratio (C 2 /C 1 ) of the content of the silver nanoparticles (C 2 ) comprised in the second section to the content of the silver nanoparticles (C 1 ) comprised in the first section after charge and discharge is within a range of 0.4 to 2.
  15. The method for manufacturing an all-solid-state battery according to claim 14, wherein the silver nanoparticles are irregularly shaped.

Description

Technical Field This application claims the benefit of priority on the basis of Korean Patent Application No. 2024-0025711, filed on February 22, 2024, and the entire contents disclosed in the Korean Patent Application are incorporated herein as a part of the specification. The present disclosure relates to an all-solid-state battery using lithium or a lithium alloy as a negative electrode active material and a method for manufacturing the same. Background Art Recently, methods of using lithium as a negative electrode active material have been studied to increase the energy density of all-solid-state batteries. As a method of using lithium as a negative electrode active material, a method of using lithium or a lithium alloy as a negative electrode active material layer during a battery manufacturing process, or a method of forming a lithium layer during a charging process without forming a separate negative electrode active material layer on a negative electrode current collector during a battery manufacturing process, has been suggested. However, if lithium is used as a negative electrode active material, lithium (metallic lithium) is precipitated on the negative electrode side during charging, and as the charging and discharging process is repeated, lithium dendrites grow through the gaps in a solid electrolyte layer, which causes defects such as battery short circuit or capacity reduction. Therefore, in order to commercialize the method of using lithium as a negative electrode active material, the above defect is required to be improved. Disclosure of Invention Technical Goals The present disclosure is to solve the above defect, and aims to provide an all-solid-state battery in which an anode-free coating layer includes irregularly shaped silver nanoparticles, thereby exhibiting excellent reactivity between silver nanoparticles and lithium ions and excellent lithium ion conductivity, and excellent distribution characteristics of silver nanoparticles even after charge and discharge, and accordingly, uniform distribution of resistance within the battery and effective control of lithium dendrite growth may be possible, and a method for manufacturing the same. Accordingly, the all-solid-state battery of the present disclosuremay exhibit excellent capacity retention, particularly excellent capacity retention at high rates, and excellent life characteristics. Technical solutions The present disclosure relates to an all-solid-state battery using lithium or a lithium alloy as a negative electrode active material. The all-solid-state battery includes a positive electrode, a solid electrolyte layer, an anode-free coating layer and a negative electrode current collector. The anode-free coating layer includes amorphous carbon and silver nanoparticles, and when the anode-free coating layer is divided into two parts in a thickness direction and sequentially referred to as a first section and a second section starting from a section close to the negative electrode collector, a ratio (C2/C1) of the content of the silver nanoparticles (C2) included in the second section to the content of the silver nanoparticles (C1) included in the first section after charge and discharge is within a range of 0.4 to 2. In an embodiment, when the anode-free coating layer is divided into three parts in the thickness direction and sequentially referred to as a first section, asecond section, and a third section from a section close to the negative electrode collector, a ratio ((C2'+C3')/C1') of the sum (C2'+C3') of the contents of the silver nanoparticles included in the second section and the third section to the content (C1') of the silver nanoparticles included in the first section after charge and discharge may be within a range of 0.4 to 5. In an embodiment, the silver nanoparticles may be irregularly shaped. In an embodiment, the maximum value of a difference among (200) plane crystal grain size, (220) plane crystal grain size, and (311) plane crystal grain size of the silver nanoparticles may be 1.5 nanometers (nm) or more. In an embodiment,a Brunauer, Emmett and Teller (BET) specific surface area of the silver nanoparticles may be 6 square meters per gram (m2/g) or less. In an embodiment, an average pore size of the silver nanoparticles may be 40 nm or more. In an embodiment, a total pore volume of the silver nanoparticles may be 0.065 cubic centimeters per gram (cm3/g) or more. In an embodiment, the amorphous carbon may be one or more selected from the group consisting of carbon black, acetylene black, furnace black, Ketjen black and graphene. In an embodiment, the silver nanoparticles may be included in a range of 10 parts by weight to 50 parts by weight relative to 100 parts by weight of the amorphous carbon. In an embodiment, the anode-free coating layer may further include a binder. In an embodiment, the solid electrolyte layer may include a sulfide-based solid electrolyte. In an embodiment, the sulfide-based solid electrolyte