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US-20260128316-A1 - BINDER FOR ALL-SOLID-STATE SECONDARY BATTERY, INORGANIC SOLID ELECTROLYTE-CONTAINING COMPOSITION, SHEET FOR ALL-SOLID-STATE SECONDARY BATTERY, AND ALL-SOLID-STATE SECONDARY BATTERY

US20260128316A1US 20260128316 A1US20260128316 A1US 20260128316A1US-20260128316-A1

Abstract

Provided are a binder for an all-solid-state secondary battery, which contains a polymer represented by Formula (I) and having an acid value of 3 mgKOH/g or less; an inorganic solid electrolyte-containing composition containing the binder, an inorganic solid electrolyte, and a dispersion medium; and a sheet for an all-solid-state secondary battery and an all-solid-state secondary battery using the composition. In Formula (I), R 1 represents an (m+n)-valent linking group, A 1 represents a hydrogen atom, or a functional group or a polymer chain, including at least one amide substituent, A 2 represents a functional group or a polymer chain, including at least one of a fluorine atom or a polysiloxane structure, n represents an integer of 1 to 8, and m represents an integer of 1 to 9, where m+n represents an integer of 2 to 10.

Inventors

  • Yuzo Nagata
  • Koji Yasuda

Assignees

  • FUJIFILM CORPORATION

Dates

Publication Date
20260507
Application Date
20251218
Priority Date
20230630

Claims (15)

  1. 1 . A binder for an all-solid-state secondary battery, comprising: a polymer which is represented by Formula (I) and has an acid value of 3 mgKOH/g or less, in Formula (I), R 1 represents an (m+n)-valent linking group, A 1 represents a hydrogen atom, or a functional group or a polymer chain, including at least one of an amide group, a sulfonamide group, or an imide group, A 2 represents a functional group or a polymer chain, including at least one of a fluorine atom or a polysiloxane structure, n represents an integer of 1 to 8, and m represents an integer of 1 to 9, where m+n represents an integer of 2 to 10.
  2. 2 . The binder for an all-solid-state secondary battery according to claim 1 , wherein A 1 represents a functional group or a polymer chain, including at least one of an amide group, a sulfonamide group, or an imide group.
  3. 3 . The binder for an all-solid-state secondary battery according to claim 1 , wherein A 2 includes a functional group or a polymer chain, including a polysiloxane structure.
  4. 4 . The binder for an all-solid-state secondary battery according to claim 1 , wherein the acid value of the polymer is 0.5 mgKOH/g or less, and a base value of the polymer is 0.5 mgKOH/g or less.
  5. 5 . The binder for an all-solid-state secondary battery according to claim 1 , wherein A 1 includes a polymer chain of a (meth)acrylamide compound.
  6. 6 . The binder for an all-solid-state secondary battery according to claim 1 , wherein A 1 includes a hydrogen atom and a polymer chain of a (meth)acrylamide compound.
  7. 7 . The binder for an all-solid-state secondary battery according to claim 1 , wherein a content of A 1 in the polymer is 1% to 30% by mass.
  8. 8 . The binder for an all-solid-state secondary battery according to claim 1 , wherein a weight-average molecular weight of the polymer is 30,000 or less.
  9. 9 . An inorganic solid electrolyte-containing composition comprising: the binder for an all-solid-state secondary battery according to claim 1 ; an inorganic solid electrolyte having conductivity of an ion of a metal belonging to Group 1 or Group 2 of the periodic table; and a dispersion medium.
  10. 10 . The inorganic solid electrolyte-containing composition according to claim 9 , further comprising: an active material.
  11. 11 . The inorganic solid electrolyte-containing composition according to claim 9 , further comprising: a conductive auxiliary agent.
  12. 12 . A sheet for an all-solid-state secondary battery, comprising: a layer formed of the inorganic solid electrolyte-containing composition according to claim 9 .
  13. 13 . A sheet for an all-solid-state secondary battery, comprising: an active material layer formed of the inorganic solid electrolyte-containing composition according to claim 10 .
  14. 14 . An all-solid-state secondary battery comprising, in the following order: a positive electrode active material layer; a solid electrolyte layer; and a negative electrode active material layer, wherein at least one of the positive electrode active material layer, the solid electrolyte layer, or the negative electrode active material layer is a layer formed of the inorganic solid electrolyte-containing composition according to claim 9 .
  15. 15 . An all-solid-state secondary battery comprising, in the following order: a positive electrode active material layer; a solid electrolyte layer; and a negative electrode active material layer, wherein at least one of the positive electrode active material layer or the negative electrode active material layer is a layer formed of the inorganic solid electrolyte-containing composition according to claim 10 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Continuation of PCT International Application No. PCT/JP2024/023135 filed on Jun. 26, 2024, which claims priority under 35 U.S.C. § 119 (a) to Japanese Patent Application No. 2023-108489 filed in Japan on Jun. 30, 2023, and JP2023-220463 filed in Japan on Dec. 27, 2023. Each of the above applications is hereby expressly incorporated by reference, in its entirety, into the present application. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder for an all-solid-state secondary battery, an inorganic solid electrolyte-containing composition, a sheet for an all-solid-state secondary battery, and an all-solid-state secondary battery. 2. Description of the Related Art In an all-solid-state secondary battery, all of a negative electrode, an electrolyte, and a positive electrode consist of solid, and the all-solid-state secondary battery can greatly improve safety and reliability, which are said to be problems to be solved in a secondary battery in which an organic electrolytic solution is used. It is also said to be capable of extending battery life. Furthermore, the all-solid-state secondary battery can be provided with a structure in which the electrodes and the electrolyte are directly arranged in series. As a result, it is possible to increase an energy density to be high as compared with the secondary battery in which an organic electrolytic solution is used, and thus the application to electric vehicles, large-sized storage batteries, and the like is expected. In such an all-solid-state secondary battery, a constituent layer (a solid electrolyte layer, a negative electrode active material layer, a positive electrode active material layer, or the like) is composed of solid particles such as an inorganic solid electrolyte, an active material, and a conductive auxiliary agent, and a binder which binds these solid particles in the constituent layer is also used in combination in general. In consideration of improvement in productivity and the like, the constituent layer is usually formed of a constituent layer-forming material containing the solid particles and the binder. Therefore, studies on the binder and the constituent layer-forming material have been carried out. For example, JP2015-164125A discloses, as a binder, a multibranched polymer which is an amorphous polymer and has a core portion and at least three polymeric arm portions bonded to the core portion, and a solid electrolyte composition containing the multibranched polymer and an inorganic solid electrolyte. Specifically, a solid electrolyte composition containing a particulate multibranched polymer having a polymer chain in which all arm portions bonded to the core portion have the same constitutional component, the polymer chain being a copolymer chain of an acidic group-containing (meth)acrylic acid-based monomer and a methacrylic acid alkyl monomer, a homopolymer chain of a methacrylic acid alkyl monomer, or a copolymer chain of a methacrylic acid alkyl monomer, an inorganic solid electrolyte, and a dispersion medium is disclosed. In addition, WO2020/067106A discloses, as a binder, a polymer represented by Formula 1, and a solid electrolyte composition containing the polymer and an inorganic solid electrolyte. In WO2020/067106A, as an example of the polymer represented by Formula 1, a polymer D-14 (acid value: approximately 4 mgKOH/g) having a polymer chain of a methacrylamide which has a sulfonic acid group as “(A1)p-R2—” of Formula 1 is disclosed. “in the formula, R1 represents an (m+n)-valent linking group, A1 represents an acidic group, a group having a basic nitrogen atom, a urea group, a urethane group, an alkoxysilyl group, an epoxy group, an isocyanate group, or a hydroxyl group, p represents an integer of 1 to 10, R2 and R3 represent a single bond or a linking group, Pc represents a polymer chain which has a constitutional component including at least one selected from a fluoroalkylene group or a siloxane structure, m represents an integer of 1 to 8, and n represents an integer of 2 to 9, where m+n represents an integer of 3 to 10” SUMMARY OF THE INVENTION In the all-solid-state secondary battery including the constituent layer formed of the constituent layer-forming material, from the viewpoint of improving battery performance (for example, reducing battery resistance), it is required that the solid particles are dispersed in the dispersion medium without being deteriorated or decomposed (dispersion state of the solid particles) in the constituent layer-forming material. In addition, in recent years, research and development of high performance, practicality, and the like of electric vehicles have been rapidly progressing, and the performance required for the all-solid-state secondary battery has also been increased. Therefore, it is required to further improve the dispersion state of the solid particles in the constituent layer-f