US-12620619-B2 - Inorganic solid electrolyte-containing composition, sheet for all-solid state secondary battery, and all-solid state secondary battery, and manufacturing methods for sheet for all-solid state secondary battery and all-solid state secondary battery

US12620619B2US 12620619 B2US12620619 B2US 12620619B2US-12620619-B2

Abstract

There are provided an inorganic solid electrolyte-containing composition including an inorganic solid electrolyte having an ion conductivity of a metal belonging to Group 1 or Group 2 in the periodic table, a polymer binder, and a dispersion medium, where the inorganic solid electrolyte-containing composition contains a polymer which has a constitutional component having a glass transition temperature (Tg HP ) of 50° C. or higher and an SP value of 20.0 MPa 1/2 or more in a case where the constitutional component is formed into a homopolymer and is dissolved in a dispersion medium. There are also provided a sheet for an all-solid state secondary battery and an all-solid state secondary battery, in which this inorganic solid electrolyte-containing composition is used, and manufacturing methods for a sheet for an all-solid state secondary battery, and an all-solid state secondary battery.

Inventors

Yo KUSHIDA
Koji Yasuda
Yuzo Nagata

Assignees

FUJIFILM CORPORATION

Dates

Publication Date: 20260505
Application Date: 20230308
Priority Date: 20200928

Claims (14)

1 . An inorganic solid electrolyte-containing composition comprising: an inorganic solid electrolyte having an ion conductivity of a metal belonging to Group 1 or Group 2 in the periodic table; a polymer binder; and a dispersion medium, wherein the polymer binder contains a polymer having a constitutional component satisfying the following (A) and (B) and is dissolved in the dispersion medium, (A) a glass transition temperature (Tg HP ) in a case where the constitutional component is formed into a homopolymer is 50° C. or higher, and (B) an SP value in a case where the constitutional component is formed into a homopolymer is 20.0 MPa 1/2 or more and 25.0 MPa 1/2 or less.
2 . The inorganic solid electrolyte-containing composition according to claim 1 , wherein a glass transition temperature (Tg B ) of the polymer is 0 to 90° C.
3 . The inorganic solid electrolyte-containing composition according to claim 1 , wherein the polymer has an additional constitutional component exhibiting a glass transition temperature at which a difference (absolute value) from the glass transition temperature (Tg HP ) of the constitutional component satisfying the (A) and the (B) is 130° C. or higher.
4 . The inorganic solid electrolyte-containing composition according to claim 1 , wherein the constitutional component satisfying the (A) and the (B) has an aromatic ring as a partial structure.
5 . The inorganic solid electrolyte-containing composition according to claim 4 , wherein the aromatic ring is an aromatic hydrocarbon ring.
6 . The inorganic solid electrolyte-containing composition according to claim 1 , wherein the constitutional component satisfying the (A) and the (B) is represented by Formula (HC), In Formula (HC), R H1 to R H3 represent a hydrogen atom or a substituent, L H represents a single bond or a linking group, and X H represents a monocyclic or polycyclic aromatic ring.
7 . The inorganic solid electrolyte-containing composition according to claim 1 , wherein the dispersion medium has an SP value of 14 to 24 MPa 1/2 .
8 . The inorganic solid electrolyte-containing composition according to claim 1 , further comprising an active material.
9 . The inorganic solid electrolyte-containing composition according to claim 1 , further comprising a conductive auxiliary agent.
10 . The inorganic solid electrolyte-containing composition according to claim 1 , wherein the inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte.
11 . A sheet for an all-solid state secondary battery, comprising a layer formed of the inorganic solid electrolyte-containing composition according to claim 1 .
12 . 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 1 .
13 . A manufacturing method for a sheet for an all-solid state secondary battery, the manufacturing method comprising forming a film of the inorganic solid electrolyte-containing composition according to claim 1 .
14 . A manufacturing method for an all-solid state secondary battery, the manufacturing method comprising manufacturing an all-solid state secondary battery through the manufacturing method according to claim 13 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Continuation of PCT International Application No. PCT/JP2021/035331 filed on Sep. 27, 2021, which claims priority under 35 U.S.C. § 119 (a) to Japanese Patent Application No. 2020-162143 filed in Japan on Sep. 28, 2020. 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 an inorganic solid electrolyte-containing composition, a sheet for an all-solid state secondary battery, and an all-solid state secondary battery, and manufacturing methods for a sheet for an all-solid state secondary battery and an all-solid state secondary battery. 2. Description of the Related Art A secondary battery is a storage battery that includes a negative electrode, a positive electrode, and an electrolyte between the negative electrode and the positive electrode and enables charging and discharging by the reciprocal migration of specific metal ions such as lithium ions between both electrodes. Examples of the representative secondary battery include a secondary battery in which a non-aqueous electrolyte such as an organic electrolytic solution is filled between a negative electrode active material layer and a positive electrode active material layer. This non-aqueous electrolyte secondary battery exhibits relatively high battery performance and thus is used in a wide range of use applications. Such a non-aqueous electrolyte secondary battery is manufactured by various methods. For example, the negative electrode active material layer and the positive electrode active material layer are generally formed of a material containing an active material and a binder. For example, JP2018-200889A proposes a positive electrode slurry for a secondary battery which is a positive electrode slurry for a secondary battery, containing a positive electrode active material, a conductive agent, a binder, and a dispersion medium, where the binder contains “a first polymer that is a fluorine-containing polymer” and “a second polymer that has a polymerization unit having a nitrile group, a polymerization unit having a hydrophilic group, a (meth)acrylic acid ester polymerization unit, and a linear alkylene polymerization unit having 4 or more carbon atoms” at a specific mass ratio. In the above-described non-aqueous electrolyte secondary battery, the non-aqueous electrolyte which is an organic electrolytic solution generally leakages easily, and a short circuit easily occurs in the inside of the battery due to overcharging or overdischarging. As a result, there is a demand for additional improvement in safety and reliability. Under these circumstances, an all-solid state secondary battery in which an inorganic solid electrolyte is used instead of the organic electrolytic solution has attracted attention. In this all-solid state secondary battery, since all of the negative electrode, the electrolyte, and the positive electrode are solid, safety and reliability which are considered as a problem of the non-aqueous electrolyte secondary battery can be significantly improved. It is also said to be capable of extending the battery life. Furthermore, all-solid state secondary batteries can be provided with a structure in which the electrodes and the electrolyte are directly disposed in series. As a result, it becomes possible to increase the energy density to be high as compared with a 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 anticipated. In such an all-solid state secondary battery, examples of substances that form constitutional layers (a solid electrolyte layer, a negative electrode active material layer, a positive electrode active material layer, and the like) include an inorganic solid electrolyte and an active material. In recent years, this inorganic solid electrolyte, particularly an oxide-based inorganic solid electrolyte or a sulfide-based inorganic solid electrolyte is expected as an electrolyte material having a high ion conductivity comparable to that of the organic electrolytic solution. In consideration of the improvement in productivity, a constitutional layer using such an inorganic solid electrolyte is generally formed of a material (a constitutional layer forming material) containing an inorganic solid electrolyte and a binder. As such a constitutional layer forming material, WO2016/017758A1 discloses, for example, a solid electrolyte composition that contains an inorganic solid electrolyte having a conductivity of an ion of a metal belonging to Group 1 or Group 2 of the periodic table and a binder composed of a polymeric compound in which (i) a linking structure of the main chain is composed of carbon atoms, (ii) a repeating unit represented by a specific formula is provided, and (iii) at least one of