Battery, sheet, and manufacturing method of both, inorganic solid electrolyte-containing composition

Abstract

This invention provides an inorganic solid electrolyte composition, a sheet for an all-solid-state secondary battery using the inorganic solid electrolyte composition, an all-solid-state secondary battery, and a method for manufacturing the sheet for the all-solid-state secondary battery and the all-solid-state secondary battery. The inorganic solid electrolyte composition exhibits excellent dispersibility, and the inorganic solid electrolyte is not easily degraded, forming a constituent layer with high ionic conductivity even at low temperatures. The inorganic solid electrolyte composition contains an inorganic solid electrolyte, a polymer binder, and a dispersion medium. The polymer binder has a surface energy of less than 20 mN / m and a pressure of 14–21.5 MPa. 1 / 2 The polymer with the SP value is dissolved in the above dispersion medium.

Description

Technical Field

[0001] This invention relates to a composition containing an inorganic solid electrolyte, a sheet for an all-solid-state secondary battery, an all-solid-state secondary battery, and a method for manufacturing the sheet for an all-solid-state secondary battery and the all-solid-state secondary battery. Background Technology

[0002] In all-solid-state secondary batteries, all the negative electrode, electrolyte, and positive electrode are made of solids, which can significantly improve the safety and reliability of batteries using organic electrolytes. It also extends battery life. Furthermore, all-solid-state secondary batteries can be configured with electrodes and electrolytes directly arranged and connected in series. Therefore, compared to secondary batteries using organic electrolytes, they can achieve higher energy density and are expected to be used in electric vehicles or large-capacity batteries.

[0003] In this type of all-solid-state secondary battery, solid materials such as inorganic solid electrolytes and active materials can be used as the materials forming the constituent layers (solid electrolyte layer, negative electrode active material layer, positive electrode active material layer, etc.). In recent years, inorganic solid electrolytes, especially oxide-based and sulfide-based inorganic solid electrolytes, have been anticipated as electrolyte materials with high ionic conductivity approaching that of organic electrolytes.

[0004] However, even if the material itself exhibits high ionic conductivity, the constituent layer, composed of solid particles such as inorganic solid electrolytes, active materials, and conductive additives, restricts the interfacial contact between these solid particles, leading to an increase in interfacial resistance (and a decrease in ionic conductivity). Moreover, in all-solid-state secondary batteries with this constituent layer, energy loss increases during repeated charge-discharge cycles, resulting in reduced cycle performance.

[0005] To suppress this increase in interfacial resistance, compositions containing particulate polymer binders, in addition to the aforementioned inorganic solid electrolyte and dispersion medium, have been proposed as materials for forming the constituent layers of all-solid-state secondary batteries (constituent layer forming materials). For example, Patent Document 1 describes a solid electrolyte composition comprising an inorganic solid electrolyte having conductive ions of metal elements belonging to Group 1 or Group 2 of the periodic table, and containing an SP value of 10.5 cal. 1 / 2 cm -3 / 2 The above polymers and adhesive particles and dispersion media with an average particle size of 10 nm or more and 50,000 nm or less.

[0006] Previous technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2017 / 099247A1 Summary of the Invention

[0009] The technical problem to be solved by the invention

[0010] In the constituent layer forming materials of all-solid-state secondary batteries, from the viewpoint of improving battery performance (e.g., ionic conductivity, cycle characteristics), it is required that solid particles be highly dispersed in the dispersion medium.

[0011] Furthermore, the development of all-solid-state rechargeable batteries for practical application has been rapid in recent years, requiring corresponding countermeasures. For example, with the expansion of applications for all-solid-state rechargeable batteries, maintaining high ionic conductivity is required not only at room temperature (e.g., 15–35°C) but also at low temperatures such as below 5°C. In addition, there is the inherent problem that inorganic solid electrolytes are prone to degradation (decomposition) due to water. In particular, from an industrial manufacturing perspective, suppressing degradation during the manufacturing process has become an important issue. However, even considering the scale of industrial manufacturing equipment, it is difficult to completely remove moisture from the environment containing the manufacturing atmosphere; therefore, research is needed from the perspective of materials forming the constituent layers.

[0012] The objective of this invention is to provide a composition containing an inorganic solid electrolyte that exhibits excellent dispersibility and is resistant to degradation, and can form a constituent layer that exhibits high ionic conductivity even at low temperatures. Furthermore, the objective of this invention is to provide a sheet for an all-solid-state secondary battery and an all-solid-state secondary battery having a constituent layer formed using the inorganic solid electrolyte composition, as well as a method for manufacturing the sheet for an all-solid-state secondary battery and the all-solid-state secondary battery using the aforementioned inorganic solid electrolyte composition.

[0013] means for solving technical problems

[0014] Based on the above considerations, the inventors conducted various studies on polymer binders used in conjunction with inorganic solid electrolytes and dispersion media. They discovered that instead of dispersing the polymer binder in particulate form within the dispersion medium, the properties of dissolving in the dispersion medium are imparted to the polymer binder. This is achieved by reducing the surface energy of the polymer binder to below 20 mN / m and the SP value to 14–21.5 MPa. 1 / 2The formation of the polymer improves the dispersibility of solid particles such as inorganic solid electrolytes and suppresses degradation caused by moisture in the inorganic solid electrolyte. Furthermore, it has been discovered that by using an inorganic solid electrolyte composition containing this specific polymer binder, inorganic solid electrolyte, and dispersion medium as the constituent layer forming material, it is possible to achieve a sheet for an all-solid-state secondary battery with a constituent layer that exhibits low resistance and is resistant to degradation even at low temperatures, as well as an all-solid-state secondary battery that exhibits low resistance and excellent cycle characteristics even at low temperatures. Based on these insights, the present invention was further developed through repeated research.

[0015] That is, the above-mentioned problems are solved through the following solutions.

[0016] <1> A composition containing an inorganic solid electrolyte, comprising an inorganic solid electrolyte having conductive ions of metals belonging to Group 1 or Group 2 of the periodic table, a polymer binder, and a dispersion medium, wherein,

[0017] Polymer adhesives contain materials with a surface energy below 20 mN / m and an SP value of 14–21.5 MPa. 1 / 2 The polymer is dissolved in the dispersion medium.

[0018] <2> According to the inorganic solid electrolyte composition described in <1>, wherein,

[0019] The polymer has an elastic modulus of 1 MPa or higher.

[0020] <3> The inorganic solid electrolyte composition according to <1> or <2>, wherein,

[0021] The polymer has constituent components represented by the following formula (LF) or formula (LS) on the main chain or side chain.

[0022] [Chemical Formula 1]

[0023]

[0024] In formula (LF) or formula (LS), R 1 ~R 3 It represents a hydrogen atom or a substituent.

[0025] L represents a single bond or a linking group.

[0026] R F This indicates a substituent containing both carbon and fluorine atoms.

[0027] R S This indicates a substituent containing silicon atoms.

[0028] <4> The inorganic solid electrolyte composition according to any one of <1> to <3>, wherein,

[0029] The polymer is a grafted polymer.

[0030] <5> The inorganic solid electrolyte composition according to any one of <1> to <3>, wherein,

[0031] The polymer backbone is a block polymer.

[0032] <6> The inorganic solid electrolyte composition according to any one of <1> to <5>, wherein,

[0033] The SP value of the dispersion medium is 14–24 MPa. 1 / 2 .

[0034] <7> The inorganic solid electrolyte composition according to any one of <1> to <6> contains an active substance.

[0035] <8> The inorganic solid electrolyte composition according to any one of <1> to <7> contains a conductive additive.

[0036] <9> The inorganic solid electrolyte composition according to any one of <1> to <8>, wherein,

[0037] Inorganic solid electrolytes are sulfide-based inorganic solid electrolytes.

[0038] <10> A sheet for an all-solid-state secondary battery, having a layer composed of an inorganic solid electrolyte composition as described in any one of <1> to <9> above.

[0039] <11> An all-solid-state secondary battery, which sequentially comprises a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer, wherein,

[0040] At least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is a layer composed of an inorganic solid electrolyte composition as described in any one of <1> to <9>.

[0041] <12> A method for manufacturing a sheet for an all-solid-state secondary battery, wherein the inorganic solid electrolyte composition described in any one of <1> to <9> is used to form a film.

[0042] <13> A method for manufacturing an all-solid-state secondary battery, wherein the all-solid-state secondary battery is manufactured by the manufacturing method described in <12> above.

[0043] Invention Effects

[0044] This invention provides an inorganic solid electrolyte composition exhibiting excellent dispersibility and suppressing the degradation of inorganic solid electrolytes, and also provides an inorganic solid electrolyte composition that forms a constituent layer exhibiting high ionic conductivity even at low temperatures. Furthermore, this invention provides an all-solid-state secondary battery sheet having a layer composed of this inorganic solid electrolyte composition and an all-solid-state secondary battery. Additionally, this invention provides a method for manufacturing the all-solid-state secondary battery sheet using the inorganic solid electrolyte composition and the all-solid-state secondary battery. Attached Figure Description

[0045] Figure 1 This is a longitudinal sectional view illustrating a preferred embodiment of the all-solid-state secondary battery of the present invention.

[0046] Figure 2 This is a schematic longitudinal sectional view of the button-shaped all-solid-state secondary battery manufactured in the embodiment. Detailed Implementation

[0047] In this invention, the numerical range represented by “~” refers to the range encompassed by the values ​​recorded before and after “~” as the lower limit and upper limit values.

[0048] In this invention, the designation of a compound (e.g., when referred to as a compound by appending a compound at the end) means that in addition to the compound itself, it also includes its salt and its ions. Furthermore, it refers to derivatives that include modifications to the introduced substituents or other components without impairing the effects of this invention.

[0049] In this invention, (meth)acrylic acid refers to one or both of acrylic acid and methacrylic acid. The same applies to (meth)acrylates.

[0050] In this invention, the term "substituent, linking group, etc." (hereinafter referred to as "substituent, etc.") that is not explicitly stated as substituted or unsubstituted means that the group may also have suitable substituents. Therefore, in this invention, even when simply described as a YYY group, the YYY group includes not only those without substituents but also those with substituents. This also applies to compounds where substitution or unsubstituent is not explicitly stated. As a preferred substituent, substituent Z, described later, can be cited as an example.

[0051] In this invention, when multiple substituents, etc., are represented by specific symbols, or when multiple substituents, etc., are specified simultaneously or selectively, it means that each substituent, etc., may be the same as or different from each other. Furthermore, even without special explanation, when multiple substituents, etc., are adjacent, it means that they may be linked together or fused together to form a ring.

[0052] In this invention, "polymer" refers to a polymer, but has the same meaning as "high molecular weight compound". Furthermore, "polymer adhesive" refers to an adhesive composed of polymers, including the polymer itself and adhesives formed containing polymers.

[0053] [Inorganic solid electrolyte composition]

[0054] The inorganic solid electrolyte composition of the present invention comprises an inorganic solid electrolyte having conductive ions of metals belonging to Group 1 or Group 2 of the periodic table, a polymer binder comprising a polymer exhibiting specific properties or physical characteristics (described later), and a dispersion medium. The polymer binder has the property of dissolving in the dispersion medium contained in the inorganic solid electrolyte composition (solubility). While the amount of polymer binder in the inorganic solid electrolyte composition varies, it is generally present in a state of dissolution in the dispersion medium. Thus, the polymer binder functions to disperse solid particles in the dispersion medium, thereby improving the dispersibility of solid particles in the inorganic solid electrolyte composition. Furthermore, it can enhance the adhesion between solid particles or to the current collector, thereby improving the cycle characteristics of the all-solid-state secondary battery.

[0055] In this invention, the way in which the polymer binder dissolves in the dispersion medium in the inorganic solid electrolyte composition is not limited to all ways in which the polymer binder dissolves in the dispersion medium. For example, if the solubility in the dispersion medium is 80% or more, a portion of the polymer binder may be insoluble in the inorganic solid electrolyte composition.

[0056] Furthermore, the polymer adhesive being soluble in the dispersion medium means that the polymer adhesive has a solubility of 80% or more in the dispersion medium.

[0057] The method for determining solubility is as follows: A specified amount of the polymer binder to be tested is weighed into a glass bottle, and 100 g of a dispersion medium of the same type as that contained in the inorganic solid electrolyte composition is added. The mixture is stirred for 24 hours at 80 rpm on a mixing rotor at 25°C. The transmittance of the mixture obtained after 24 hours of stirring is determined under the following conditions: This test (transmittance determination) is performed by varying the amount of binder dissolved (the specified amount mentioned above), and the upper limit concentration X (mass %) of 99.8% transmittance is defined as the solubility of the binder in the dispersion medium.

[0058] <Transmittance Measurement Conditions>

[0059] Dynamic light scattering (DLS) measurement

[0060] Apparatus: DLS-8000 DLS measuring device manufactured by Otsuka Electronics Co., Ltd.

[0061] Laser wavelength and output: 488nm / 100mW

[0062] Sample cell: NMR tube

[0063] The inorganic solid electrolyte composition of the present invention only needs to contain the above-mentioned polymer binder, and its state of existence is not particularly limited. It may or may not adsorb onto the inorganic solid electrolyte.

[0064] The polymeric adhesive functions as a binder to bond solid particles, such as inorganic solid electrolytes (and coexisting active substances and conductive additives), to each other (e.g., inorganic solid electrolytes to each other, inorganic solid electrolytes and active substances, and active substances to each other), within a constituent layer formed at least of an inorganic solid electrolyte composition. Furthermore, it functions as a binder for bonding current collectors and solid particles. In the inorganic solid electrolyte composition, the polymeric adhesive may or may not have the function of bonding solid particles to each other.

[0065] The inorganic solid electrolyte composition of the present invention is preferably a slurry formed by dispersing the inorganic solid electrolyte in a dispersion medium. In this case, the polymer binder preferably has the function of dispersing solid particles in the dispersion medium.

[0066] The inorganic solid electrolyte composition of the present invention exhibits excellent dispersibility, and the inorganic solid electrolyte is not easily degraded. By using the inorganic solid electrolyte composition as the constituent layer forming material, the degradation of the inorganic solid electrolyte caused by moisture can be suppressed. At the same time, the constituent layer can exhibit high ionic conductivity even at low temperatures, thus enabling the realization of an all-solid-state secondary battery with low resistance and excellent cycle characteristics even at low temperatures.

[0067] In the manner in which the active material layer formed on the current collector by the inorganic solid electrolyte composition of the present invention is formed, the adhesion between the current collector and the active material layer can be enhanced, and the cycling characteristics can be further improved.

[0068] The detailed reasons are still unclear, but the following is believed.

[0069] In compositions containing inorganic solid electrolytes, a polymer binder (hereinafter, sometimes simply referred to as a binder) dissolved in the dispersion medium is used. (The binder dissolved in the dispersion medium is sometimes called a solvent binder.) Therefore, this composition improves the dispersibility of solid particles such as inorganic solid electrolytes through the binder, enabling the formation of a constituent layer where solid particles are uniformly distributed rather than unevenly within the composition. It can be considered that this constituent layer is less prone to overcurrent even during the charging and discharging of an all-solid-state secondary battery, thus preventing the degradation of solid particles. This improves ionic conductivity and cycle characteristics.

[0070] In this invention, based on this, the surface energy of the polymer contained in the adhesive is set to be below 20 mN / m, and the SP value is set to be between 14 and 21.5 MPa. 1 / 2 .

[0071] By setting the polymer's SP value within the aforementioned range, the affinity of the adhesive for the dispersion medium can be further improved, enabling the adhesive in its dissolved state to be highly dispersed. Therefore, solid particles can be more uniformly distributed within the constituent layers, further enhancing the solubility-based battery characteristics.

[0072] Furthermore, soluble adhesives often tend to over-coat the surface of solid particles such as inorganic solid electrolytes, thereby increasing the interfacial resistance (contact resistance) of the inorganic solid electrolyte (reducing ionic conductivity). However, it is believed that if the surface energy of the polymer contained in the soluble adhesive is set within the aforementioned range, even if the adhesive is adsorbed onto the surface of the inorganic solid electrolyte, the adhesive will be repelled by the surface of the inorganic solid electrolyte, causing the adhesive to disperse and precipitate. This maintains direct contact between the inorganic solid electrolytes (without interfering with the adhesive's contact) without significantly damaging the strong adhesion between them. Therefore, the interfacial resistance of the inorganic solid electrolyte can be reduced, suppressing the obstruction of ion conduction between inorganic solid electrolytes even at low temperatures.

[0073] Furthermore, since the adhesive with low surface energy adsorbs onto the surface of the inorganic solid electrolyte, it can effectively prevent water from contacting the inorganic solid electrolyte. Thus, in the inorganic solid electrolyte composition and its constituent layers, it is possible to suppress the increase in resistance of the inorganic solid electrolyte at low temperatures and the increase in resistance caused by degradation.

[0074] It is believed that the inorganic solid electrolyte composition of the present invention, by combining the inorganic solid electrolyte and the dispersion medium with the above-mentioned soluble binder, can achieve the above-mentioned effects together, and thus produce an all-solid-state secondary battery with low resistance and excellent cycle characteristics even at low temperature.

[0075] When the active material layer is formed from the inorganic solid electrolyte composition of the present invention, as described above, the constituent layer is formed while maintaining a high degree of dispersion. Therefore, it is considered that the binder can contact (adhere to) the current collector surface while dispersed with solid particles. As a result, a strong adhesion between the current collector and the active material can be achieved, and further improvements in cycle characteristics and conductivity can be achieved.

[0076] The inorganic solid electrolyte composition of the present invention can be preferably used as a forming material (constituent layer forming material) for sheets (including electrode sheets for all-solid-state secondary batteries) or solid electrolyte layers or active material layers of all-solid-state secondary batteries. In particular, it can be preferably used as a forming material for negative electrode sheets or negative electrode active material layers of all-solid-state secondary batteries containing negative electrode active materials that expand and contract significantly due to charging and discharging, in which high cycle characteristics and high conductivity can also be achieved.

[0077] The inorganic solid electrolyte composition of the present invention is preferably a non-aqueous composition. In the present invention, the non-aqueous composition includes not only a water-free state but also a water content (also referred to as moisture content) preferably of 500 ppm or less. In the non-aqueous composition, the water content is more preferably 200 ppm or less, further preferably 100 ppm or less, and particularly preferably 50 ppm or less. If the inorganic solid electrolyte composition is a non-aqueous composition, the degradation of the inorganic solid electrolyte can be suppressed. The water content refers to the amount of water contained in the inorganic solid electrolyte composition (mass ratio of the inorganic solid electrolyte composition), specifically, it is defined as the value obtained by filtration using a 0.02 μm membrane filter and determination using Karl Fischer titration.

[0078] In addition to containing an inorganic solid electrolyte, the inorganic solid electrolyte composition of the present invention also includes, in the form of, an active substance and a conductive additive (the composition in this manner is referred to as an electrode composition).

[0079] The components contained in the inorganic solid electrolyte composition of the present invention and the components that may be contained therein will be described below.

[0080] <Inorganic Solid Electrolytes>

[0081] The composition containing inorganic solid electrolytes contains inorganic solid electrolytes (in the case of particulate form, also referred to as inorganic solid electrolyte particles).

[0082] In this invention, inorganic solid electrolyte refers to an inorganic solid electrolyte, which is a solid electrolyte capable of allowing ions to move within it. It is clearly distinguished from organic solid electrolytes (such as polymeric electrolytes represented by polyethylene oxide (PEO) and organic electrolyte salts represented by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)) from the perspective of not containing organic materials as the primary ion-conducting material. Furthermore, since inorganic solid electrolytes are solid in their stable state, they generally do not dissociate or ionize into cations and anions. In this respect, they are clearly distinguished from inorganic electrolyte salts (such as LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), and LiCl) that dissociate or ionize into cations and anions in electrolytes or polymers. There are no particular limitations as long as the inorganic solid electrolyte possesses the ion conductivity of metals belonging to Group 1 or Group 2 of the periodic table; it generally does not possess electronic conductivity. In the case of the all-solid-state secondary battery of the present invention being a lithium-ion battery, it is preferable that the inorganic solid electrolyte has the ionic conductivity of lithium ions.

[0083] The aforementioned inorganic solid electrolyte can be appropriately selected from solid electrolyte materials commonly used in all-solid-state secondary batteries. For example, as inorganic solid electrolytes, (i) sulfide-based inorganic solid electrolytes, (ii) oxide-based inorganic solid electrolytes, (iii) halide-based inorganic solid electrolytes, and (iv) hydride-based inorganic solid electrolytes can be mentioned. From the viewpoint of forming a better interface between the active material and the inorganic solid electrolyte, sulfide-based inorganic solid electrolytes are preferred.

[0084] (i) Sulfide-based inorganic solid electrolytes

[0085] The preferred form is a sulfide-based inorganic solid electrolyte containing sulfur atoms, possessing ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and exhibiting electronic insulation properties. The preferred form is a sulfide-based inorganic solid electrolyte containing at least Li, S, and P as elements, and exhibiting lithium-ion conductivity; however, it may contain other elements besides Li, S, and P, depending on the purpose or circumstances.

[0086] Sulfide-based inorganic solid electrolytes are particularly reactive with water among inorganic solid electrolytes, so it is important to avoid contact with water (moisture) not only during composition preparation but also during the formation of the constituent layers. However, in this invention, by using it in conjunction with the aforementioned solvent binder, the deterioration of the sulfide-based inorganic solid electrolyte can be effectively prevented.

[0087] As a sulfide-based inorganic solid electrolyte, for example, a lithium-ion conductive inorganic solid electrolyte that satisfies the composition represented by the following formula (S1) can be cited.

[0088] La1 M b1 P c1 S d1 A e1 (S1)

[0089] In the formula, L represents an element selected from Li, Na, and K, preferably Li. M represents an element selected from B, Zn, Sn, Si, Cu, Ga, Sb, Al, and Ge. A represents an element selected from I, Br, Cl, and F. a1 to e1 represent the composition ratio of each element, where a1:b1:c1:d1:e1 satisfies 1–12:0–5:1:2–12:0–10. a1 is preferably 1–9, more preferably 1.5–7.5. b1 is preferably 0–3, more preferably 0–1. d1 is preferably 2.5–10, more preferably 3.0–8.5. e1 is preferably 0–5, more preferably 0–3.

[0090] As described below, the composition ratio of each element can be controlled by adjusting the amount of raw material compounds used in the manufacture of sulfide-based inorganic solid electrolytes.

[0091] Sulfide-based inorganic solid electrolytes can be amorphous (glass), crystallized (glass-ceramic), or partially crystallized. For example, Li-PS-based glasses or Li-PS-based glass-ceramics containing Li, P, and S can be used.

[0092] Sulfide-based inorganic solid electrolytes can be manufactured by reacting at least two of the following raw materials: lithium sulfide (Li2S), phosphorus sulfide (e.g., phosphorus pentasulfide (P2S5)), monomeric phosphorus, monomeric sulfur, sodium sulfide, hydrogen sulfide, lithium halides (e.g., LiI, LiBr, LiCl), and sulfides of the element represented by M above (e.g., SiS2, SnS, GeS2).

[0093] The ratio of Li₂S to P₂S₅ in Li-PS-based glasses and Li-PS-based glass ceramics is preferably 60:40 to 90:10, more preferably 68:32 to 78:22, in terms of the molar ratio of Li₂S:P₂S₅. Setting the Li₂S to P₂S₅ ratio within this range improves lithium-ion conductivity. Specifically, the lithium-ion conductivity is preferably set to 1 × 10⁻⁶. -4 S / cm or higher, more preferably 1×10 -3 S / cm or higher. Although no specific upper limit is set, it is actually 1×10⁻⁶. -1 Below S / cm.

[0094] As specific examples of sulfide-based inorganic solid electrolytes, combinations of raw materials are illustrated below. For example, Li₂S-P₂S₅, Li₂S-P₂S₅-LiCl, Li₂S-P₂S₅-H₂S, Li₂S-P₂S₅-H₂S-LiCl, Li₂S-LiI-P₂S₅, Li₂S-LiI-Li₂O-P₂S₅, Li₂S-LiBr-P₂S₅, Li₂S-Li₂O-P₂S₅, Li₂S-Li₃PO₄-P₂S₅, Li₂S-P₂S₅-P₂O₅, Li₂S-P₂S₅-SiS₂, Li₂S-P₂S₅-SiS₂-LiCl, Li₂S-P₂S₅-SnS, and Li₂S-P₂S₅-Al₂ can be cited. S3, Li2S-GeS2, Li2S-GeS2-ZnS, Li2S-Ga2S3, Li2S-GeS2-Ga2S3, Li2S-GeS2-P2S5, Li2S-GeS2-Sb2S5, Li2S-GeS2-Al2S3, Li2S-SiS2, Li2S-Al2S3, Li2S-SiS2-Al2S3, Li2S-SiS2-P2S5, Li2S-SiS2-P2S5-LiI, Li2S-SiS2-LiI, Li2S-SiS2-Li4SiO4, Li2S-SiS2-Li3PO4, Li 10 GeP2S 12 And so on. The mixing ratio of each raw material is not limited. As a method for synthesizing sulfide-based inorganic solid electrolyte materials using this raw material composition, for example, an amorphization method can be mentioned. As an amorphization method, examples include mechanical polishing, solution processing, and melt quenching. Processing at room temperature is possible, thereby simplifying the manufacturing process.

[0095] (ii) Oxide-based inorganic solid electrolytes

[0096] Oxide-based inorganic solid electrolytes are preferably compounds containing oxygen atoms, possessing ionic conductivity of metals belonging to Group 1 or Group 2 of the periodic table, and having electronic insulation properties.

[0097] For oxide-based inorganic solid electrolytes, the preferred ionic conductivity is 1×10⁻⁶. -6 S / cm or higher, preferably 5×10 -6 S / cm or higher, especially preferably 1×10 -5 S / cm or higher. Although there is no specific upper limit, it is actually 1×10 -1 Below S / cm.

[0098] As a specific example of a compound, Li can be cited. xa La yaTiO3 [xa satisfies 0.3≤xa≤0.7, ya satisfies 0.3≤ya≤0.7.] (LLT); Li xb La yb Zr zb M bb mb O nb (M bb It consists of one or more elements selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn. xb satisfies 5 ≤ ​​xb ≤ 10, yb satisfies 1 ≤ yb ≤ 4, zb satisfies 1 ≤ zb ≤ 4, mb satisfies 0 ≤ mb ≤ 2, and nb satisfies 5 ≤ ​​nb ≤ 20. Li xc B yc M cc zc O nc (M cc It is an element selected from C, S, Al, Si, Ga, Ge, In, and Sn. xc satisfies 0 < xc ≤ 5, yc satisfies 0 < yc ≤ 1, zc satisfies 0 < zc ≤ 1, and nc satisfies 0 < nc ≤ 6. ); Li xd (Al, Ga) yd (Ti, Ge) zd Si ad P md O nd (xd satisfies 1≤xd≤3, yd satisfies 0≤yd≤1, zd satisfies 0≤zd≤2, ad satisfies 0≤ad≤1, md satisfies 1≤md≤7, nd satisfies 3≤nd≤13.) ; Li (3-2xe) M ee xe D ee O(xe) represents a number greater than 0 and less than 0.1, M ee This represents a divalent metal atom. (D) ee This represents a halogen atom or a combination of two or more halogen atoms. (Li) xf Si yf O zf (xf satisfies 1 ≤ xf ≤ 5, yf satisfies 0 < yf ≤ 3, zf satisfies 1 ≤ zf ≤ 10.) ; Li xg S yg O zg (xg satisfies 1≤xg≤3, yg satisfies 0<yg≤2, zg satisfies 1≤zg≤10.) ; Li3BO3; Li3BO3-Li2SO4; Li2O-B2O3-P2O5; Li2O-SiO2; Li6BaLa2Ta2O 12 Li3PO (4-3 / 2w) N w(w satisfies w < 1); Li has a LISICON (Lithium super ionic conductor) type crystal structure 3.5 Zn 0.25 GeO4; La with a perovskite-type crystal structure 0.55 Li 0.35 TiO3; LiTi2P3O with a NASICON (Natrium super ionic conductor) crystal structure 12 Li 1+xh+yh (Al, Ga) xh (Ti, Ge) 2-xh Si yh P 3-yh O 12 (xh satisfies 0 ≤ xh ≤ 1, yh satisfies 0 ≤ yh ≤ 1.) ; Li7La3Zr2O with garnet-type crystal structure 12 (LLZ) etc.

[0099] Furthermore, phosphorus compounds containing Li, P, and O are preferred. Examples include lithium phosphate (Li3PO4); LiPON, in which nitrogen replaces a portion of the oxygen in lithium phosphate; and LiPOD. 1 (D 1 Preferably, it contains one or more elements selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, and Au.

[0100] Furthermore, LiA can be preferably used. 1 ON(A 1 It consists of one or more elements selected from Si, B, Ge, Al, C, and Ga.

[0101] (iii) Halogen-based inorganic solid electrolytes

[0102] Halogen-based inorganic solid electrolytes are preferably compounds containing halogen atoms, possessing conductivity of ions belonging to Group 1 or Group 2 of the periodic table, and having electronic insulation properties.

[0103] There are no particular limitations on the type of inorganic solid electrolyte, such as LiCl, LiBr, LiI, and compounds like Li3YBr6 and Li3YCl6 described in ADVANCED MATERIALS, 2018, 30, 1803075. Among these, Li3YBr6 and Li3YCl6 are preferred.

[0104] (iv) Hydride-based inorganic solid electrolytes

[0105] Hydride-based inorganic solid electrolytes are preferably compounds containing hydrogen atoms, possessing ionic conductivity of metals belonging to Group 1 or Group 2 of the periodic table, and having electronic insulation properties.

[0106] There are no particular limitations as hydride-based inorganic solid electrolytes; examples include LiBH4, Li4(BH4)3I, and 3LiBH4-LiCl.

[0107] The inorganic solid electrolyte is preferably a particle. In this case, the particle size (volume average particle size) of the inorganic solid electrolyte is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.1 μm or more. As an upper limit, it is preferably 100 μm or less, more preferably 50 μm or less.

[0108] The particle size of the inorganic solid electrolyte was determined using the following steps. A 1% (w / w) dispersion of the inorganic solid electrolyte particles was prepared by diluting the particles with water (or heptane in the case of substances unstable in water) in a 20 mL sample vial. The diluted dispersion sample was irradiated with ultrasound at 1 kHz for 10 minutes and then immediately used in the test. Using this dispersion sample, 50 data acquisitions were performed using a laser diffraction / scattering particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA, Ltd.) at 25°C using a measuring quartz cell to obtain the volume average particle size. Other detailed conditions were described in JIS Z8828:2013 "Particle Size Analysis - Dynamic Light Scattering Method" as needed. Five samples were prepared for each grade, and their average value was used.

[0109] The inorganic solid electrolyte composition may contain one or more types of inorganic solid electrolytes.

[0110] There is no particular limitation on the content of inorganic solid electrolyte in the inorganic solid electrolyte composition. In terms of dispersibility and ionic conductivity, it is preferable that the solid content is 50% or more out of 100% by mass, more preferably 70% or more by mass, and especially preferably 90% or more by mass. As an upper limit, from the same point of view, it is preferable that it is 99.9% or less by mass, more preferably 99.5% or less by mass, and especially preferably 99% or less by mass.

[0111] However, when the inorganic solid electrolyte composition contains the active substance described later, the total content of the active substance and the inorganic solid electrolyte in the inorganic solid electrolyte composition is preferably within the range described above.

[0112] In this invention, solid components refer to those components that, when dried at 150°C for 6 hours under a nitrogen atmosphere and at a pressure of 1 mmHg, volatilize or evaporate without disappearing. Typically, this refers to components other than the dispersion medium described later.

[0113] <Polymer Adhesives>

[0114] The inorganic solid electrolyte composition of the present invention contains one or more polymer binders. The polymer binders used in the present invention have a surface energy of less than 20 mN / m and an SP value of 14–21.5 MPa. 1 / 2 The polymer binder is formed and dissolved in the dispersion medium contained in the inorganic solid electrolyte composition. By using this polymer binder in combination with the inorganic solid electrolyte and the dispersion medium, it is possible to prepare an inorganic solid electrolyte composition with excellent dispersibility and resistance to degradation of the inorganic solid electrolyte, thereby enabling the fabrication of a constituent layer that exhibits high ionic conductivity and resistance to degradation even at low temperatures.

[0115] As long as the polymers contained in the polymer adhesive meet the above-mentioned surface energy and SP values, other polymers may be included, provided that the function of these components is not impaired.

[0116] (The physical properties or characteristics of polymer adhesives or the polymers formed by adhesives, etc.)

[0117] To address the problems of this invention, the surface energy and SP value, characteristic properties of polymers forming polymeric adhesives (also known as adhesive-forming polymers), are explained.

[0118] The binder-forming polymer has a surface energy of less than 20 mN / m. With this surface energy range, as described above, the binder containing the binder-forming polymer can reduce the interfacial resistance of solid particles such as inorganic solid electrolytes while also preventing the degradation of the inorganic solid electrolytes.

[0119] The surface energy of the adhesive-forming polymer is preferably 18 mN / m or less, more preferably 16 mN / m or less, and even more preferably 14 mN / m or less. There is no particular limitation on the lower limit of the surface energy, but it is practically 3 mN / m or more, preferably 5 mN / m or more, more preferably 8 mN / m or more, and even more preferably 9 mN / m or more. The surface energy of the adhesive-forming polymer is set as a value calculated by the method described in the examples.

[0120] The binder-forming polymer has a strength of 14–21.5 MPa. 1 / 2The SP value. With an SP value within this range, as mentioned above, the dispersibility of the binder dissolved in the dispersion medium can be further improved. The SP value of the binder-forming polymer is preferably less than 21.5 MPa. 1 / 2 More preferably 20 MPa 1 / 2 Hereinafter, 19 MPa is further preferred. 1 / 2 The lower limit of the SP value is preferably 15 MPa. 1 / 2 The above is preferred, and more preferably 16 MPa. 1 / 2 The above is further preferred to be 17 MPa. 1 / 2 above.

[0121] The calculation method for SP values ​​is explained.

[0122] First, unless otherwise stated, the SP values ​​(MPa) of each component constituting the adhesive polymer are determined using the Hoy method. 1 / 2 )(Refer to HLHoy JOURNAL OF PAINT TECHNOLOGY Vol.42, No.541, 1970, 76-118, and POLYMER HANDBOOK 4 th Chapter 59, VII, page 686 (Tables 5 and 6 and the formulas in Table 6).

[0123] As needed, the SP values ​​obtained from the above literature are converted into SP values ​​(MPa). 1 / 2 (For example, 1cal) 1 / 2 cm -3 / 2 ≈2.05J 1 / 2 cm -3 / 2 ≈2.05MPa 1 / 2 ).

[0124] [Formula 1]

[0125]

[0126] Using the SP values ​​(MPa) of the constituent components determined above. 1 / 2 The SP value (MPa) of the adhesive-formed polymer is calculated using the following formula. 1 / 2 ).

[0127] SP 2 =(SP1 2 ×W1)+(SP2 2 ×W2)+……

[0128] In the formula, SP1, SP2, ... represent the SP values ​​of the constituent components, and W1, W2, ... represent the mass fractions of the constituent components. The mass fraction of a constituent component is the mass fraction of that constituent component (the raw material compound into which the constituent component is introduced) in the binder-formed polymer.

[0129] The SP value of the adhesive forming polymer can be adjusted according to the type and composition (type and content of constituent components) of the adhesive forming polymer.

[0130] From the viewpoint of achieving a higher degree of dispersibility, it is preferable that the SP value of the binder forming polymer, relative to the SP value of the dispersion medium, satisfies the difference (absolute value) of the SP value within the range described below.

[0131] The polymer adhesive or adhesive-forming polymer used in this invention preferably has the following physical properties or characteristics.

[0132] The binder-forming polymer preferably has a (tensile) elastic modulus of 1 MPa or higher. Having an elastic modulus in this range allows for further enhancement of the cohesive force of the solid particles, and also promises improved film-forming properties of the inorganic solid electrolyte composition. As a result, this contributes to further improving the cycle characteristics of all-solid-state secondary batteries.

[0133] The elastic modulus of the adhesive-formed polymer is preferably 5 MPa or more, more preferably 10 MPa or more, and even more preferably 15 MPa or more. There is no particular upper limit to the elastic modulus; practically it is 800 MPa or less, preferably 600 MPa or less, more preferably 400 MPa or less, and even more preferably 100 MPa or less. The elastic modulus of the adhesive-formed polymer is set as a value calculated by the method described in the examples.

[0134] In this invention, the elastic modulus can be appropriately set according to the type and composition of the polymer formed by the adhesive.

[0135] The moisture concentration of the polymer binder (polymer) is preferably below 100 ppm (by mass). Furthermore, this polymer binder can either crystallize and dry the polymer, or be used directly as a polymer binder dispersion.

[0136] The polymer forming the polymer binder is preferably amorphous. In this invention, "amorphous" typically means that no endothermic peak due to crystal melting is observed when measured at the glass transition temperature.

[0137] The polymer forming the polymer binder can be either a non-crosslinked polymer or a crosslinked polymer. Furthermore, when the polymer is crosslinked by heating or applying voltage, the molecular weight can be greater than the aforementioned molecular weight. Preferably, when starting to use an all-solid-state secondary battery, the mass-average molecular weight of the polymer is within the range described later.

[0138] There is no particular limitation on the mass-average molecular weight of the polymer forming the polymeric adhesive. For example, it is preferably 15,000 or more, more preferably 30,000 or more, and even more preferably 50,000 or more. As an upper limit, it is practically 5,000,000 or less, preferably 4,000,000 or less, more preferably 3,000,000 or less, and even more preferably 100,000 or less.

[0139] -Determination of molecular weight-

[0140] In this invention, the molecular weight of polymers, polymer chains, and macromonomers, unless otherwise specified, refers to the mass-average molecular weight or number-average molecular weight converted from standard polystyrene obtained by gel permeation chromatography (GPC). The determination method is generally set to the value determined by the method described in either condition 1 or condition 2 (preferred). A suitable eluent is selected and used according to the type of polymer or macromonomer.

[0141] (Condition 1)

[0142] Column: Connects 2 TOSOH TSKgel Super AWM-H (trade name, manufactured by TOSOH CORPORATION)

[0143] Charge carriers: 10 mM LiBr / N-methylpyrrolidone

[0144] Measurement temperature: 40℃

[0145] Carrier flow rate: 1.0 ml / min

[0146] Sample concentration: 0.1% by mass

[0147] Detector: RI (Refractive Index) Detector

[0148] (Condition 2)

[0149] Columns: Use columns connected to TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, and TOSOH TSKgel Super HZ2000 (all trade names, manufactured by Tosoh Corporation).

[0150] Support: Tetrahydrofuran

[0151] Measurement temperature: 40℃

[0152] Carrier flow rate: 1.0 ml / min

[0153] Sample concentration: 0.1% by mass

[0154] Detector: RI (Refractive Index) Detector

[0155] (Adhesive forms polymer)

[0156] As long as the polymer forming the binder satisfies the solubility in the dispersion medium and the aforementioned surface energy and SP value, there are no particular limitations on the type and composition of the polymer. Examples include stepwise polymers (condensation, addition, or addition condensation) such as polyurethane, polyurea, polyamide, polyimide, polyester, polycarbonate resin, and polyether resin, as well as chain polymers or copolymers thereof, such as fluoropolymers, hydrocarbon polymers, vinyl polymers, and (meth)acrylic polymers. Among these, chain polymers are preferred, and vinyl polymers or (meth)acrylic polymers are more preferred.

[0157] There are no particular restrictions on the polymerization method of the polymer formed by the binder; it can be any of the following: block polymer, alternating copolymer, random polymer, or graft polymer. A graft polymer is a polymer that has grafted chains as side chains regardless of the polymerization method of the main chain; specifically, it refers to a polymer with repeating units in the molecular chains constituting the side chains.

[0158] The adhesive forms a polymer that effectively exerts the above-mentioned effects. From the viewpoints of improving dispersibility and ionic conductivity, inhibiting the deterioration of inorganic solid electrolytes, and thus improving adhesion, block polymers with block copolymers as the main chain (regardless of the polymerization mode of the side chains) or graft polymers (regardless of the polymerization mode of the main chain) are preferred.

[0159] In this invention, the polymer backbone refers to all other molecular chains constituting the polymer that can be considered branched or comb-like linear molecular chains relative to the backbone. While the weight-average molecular weight depends on the molecular chains considered branched or comb-like, typically the longest chain constituting the polymer becomes the backbone. However, terminal groups present at the ends of the polymer are not included in the backbone. Furthermore, polymer side chains refer to molecular chains other than the backbone, including short molecular chains and long molecular chains (grafted chains).

[0160] The composition and content of the binder-forming polymer are determined within the range that satisfies the solubility, surface energy, and SP value of the dispersion medium, as detailed later.

[0161] Regarding preferred (meth)acrylic acid polymers as adhesive forming polymers, examples include polymers obtained by (co)polymerizing (meth)acrylic acid compound (M1) and containing 50% by mass or more of the constituent components derived from (meth)acrylic acid compound (M1).

[0162] Regarding preferred vinyl polymers for forming adhesives, examples include polymers obtained by (co)polymerizing vinyl monomers other than (meth)acrylic acid compound (M1) and containing 50% by mass or more of the constituent components derived from vinyl monomers.

[0163] The adhesive forming polymer preferably contains, in addition to components derived from (meth)acrylic acid compound (M1) and components derived from ethylene monomers, components derived from olefinic unsaturated monomers (polymeric compounds) having fluorine or silicon atoms, and components derived from macromolecular monomers.

[0164] Examples of olefinic unsaturated monomers having fluorine or silicon atoms include compounds having an olefinic unsaturated group (polymeric group) and a fluorine atom or a group containing a fluorine or silicon atom. There are no particular limitations on the groups containing fluorine or silicon atoms; examples include R in the following formula (LF). F R in equation (LS) S The olefinic unsaturated group can be directly bonded to a group containing a fluorine atom or a silicon atom, or it can be bonded via a linking group. There are no particular limitations on the linking group used to bond the olefinic unsaturated group to the group containing a fluorine atom or a silicon atom; for example, L in formula (LF) described later. Examples of such olefinic unsaturated monomers include fluorinated ethylenes such as tetrafluoroethylene (TFE) and vinylidene fluoride (VdF), and compounds deriving their constituent components from formula (LF) or formula (LS).

[0165] As a compound that introduces a constituent element represented by the following formula (LF) or formula (LS), examples of compounds that introduce a constituent element represented by the following polymers and polymers of the introduction examples include hexafluoropropylene (HFP).

[0166] [Chemical Formula 2]

[0167]

[0168] In formula (LF) or formula (LS), R 1 ~R 3 It represents a hydrogen atom or a substituent.

[0169] As R 1 ~R 3There are no particular restrictions on the substituents that can be used; they can be selected from the substituents Z described later, preferably alkyl or halogen atoms. R 1 and R 3 Preferably, each is a hydrogen atom, R 2 Preferably, it contains hydrogen atoms or methyl groups.

[0170] L represents a single bond or a linking group, preferably a linking group.

[0171] There are no particular limitations on the linking group that can be used as L. Examples include alkylene groups (preferably 1 to 12 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 3), alkenyl groups (preferably 2 to 6 carbon atoms, more preferably 2 to 3), aryl groups (preferably 6 to 24 carbon atoms, more preferably 6 to 10), oxygen atoms, sulfur atoms, and imino groups (-NR). N -:R N This refers to a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Other related groups include carbonyl groups, phosphate linkages (-OP(OH)(O)-O-), phosphonic acid linkages (-P(OH)(O)-O-), or combinations thereof. Preferably, the linkage group is a group composed of an alkylene group, an arylene group, a carbonyl group, an oxygen atom, a sulfur atom, and an imino group; more preferably, it is a group composed of an alkylene group, an arylene group, a carbonyl group, an oxygen atom, and an imino group; and even more preferably, it includes a -CO-O- group or a -CO-N(R) group. N )-base(R N The group represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Particularly preferred are -CO-O- or -CO-N(R) groups. N (R) N As described above. The number of atoms constituting the linking group and the number of linking atoms are as follows. However, the polyalkoxide chain constituting the linking group is not limited to the above.

[0172] In this invention, the number of atoms constituting the linking group is preferably 1 to 36, more preferably 1 to 24, even more preferably 1 to 12, and particularly preferably 1 to 6. The number of connecting atoms in the linking group is preferably 10 or less, more preferably 8 or less. A lower limit is 1 or more. The above-mentioned number of connecting atoms refers to the minimum number of atoms connecting the defined structural parts. For example, in the case of -CH2-C(=O)-O-, the number of atoms constituting the linking group is 6, but the number of connecting atoms is 3.

[0173] The aforementioned hydrocarbon group (alkyl group, etc.) and the aforementioned linking group may or may not have substituents. Examples of possible substituents include substituent Z, and preferably halogen atoms.

[0174] R FRepresents a substituent containing a carbon atom and a fluorine atom. As a substituent containing two atoms, there is no particular limitation. For example, a fluorine-substituted hydrocarbon group can be cited. Specifically, a fluoroalkyl group, a fluoroaryl group, etc. can be cited. Among them, a fluoroalkyl group is preferred, and a primary fluoroalkyl group is more preferred from the viewpoints of reducing interfacial resistance and preventing deterioration.

[0175] As the fluoroalkyl group, it is a group obtained by substituting at least one hydrogen atom in an alkyl group or a cycloalkyl group with a fluorine atom. The number of carbon atoms is preferably 1 to 20, more preferably 2 to 15, further preferably 3 to 10, and particularly preferably 4 to 8 from the viewpoints of reducing interfacial resistance and preventing deterioration. The number of fluorine atoms on the carbon atom can be a part of the substituted hydrogen atoms or all of them (perfluoroalkyl group). Among them, it is preferred that the carbon atom bonded to L in the formula is not substituted with fluorine, and more preferably the carbon atom on the terminal side of the alkyl group is substituted with fluorine. For example, a fluoroalkyl group represented by the formula: C n F (2n+1) C m H (2m) - can be preferably cited. In the formula, m is 1 or 2, and the sum of n and m is the same as the number of carbon atoms of the above alkyl group.

[0176] As the fluoroaryl group, it is a group obtained by substituting at least one hydrogen atom in an aromatic hydrocarbon with a fluorine atom. The number of carbon atoms is preferably 6 to 24, and more preferably 6 to 10. The number of fluorine atoms on the carbon atom can be a part of the substituted hydrogen atoms or all of them (perfluoroaryl group).

[0177] As specific examples of the fluoroalkyl group and the fluoroaryl group, each group possessed by the polymers synthesized in the exemplified polymers and examples described later can be cited, but the present invention is not limited to these.

[0178] R S Represents a substituent containing a silicon atom. As a substituent containing a silicon atom, a siloxanyl group can be preferably cited. For example, a group having a structure represented by -(SiR2-O) n - is preferred. R represents a hydrogen atom or a substituent, and a substituent is preferred. As the substituent, there is no particular limitation, and a substituent selected from the substituents Z described later can be cited, and an alkyl group or an aryl group is preferred. The (average) repeating number n is preferably 1 to 100, more preferably 1 to 80, and further preferably 20 to 50. The group bonded to the terminal of the structure represented by -(SiR2-O) n - is not particularly limited, and an alkyl group or an aryl group that can be used as R is preferred.

[0179] Here, when the repeating number n is 2 or more, the adhesive forming polymer having a constituent represented by the formula (LS) becomes a graft polymer, and has R in the constituent represented by the formula (LS) on its side chain S .

[0180] Examples of (meth)acrylic acid compounds (M1) include (meth)acrylic acid compounds, (meth)acrylate compounds, (meth)acrylamide compounds, (meth)acrylonitrile compounds, etc., with (meth)acrylate compounds and (meth)acrylonitrile compounds being preferred.

[0181] Examples of (meth)acrylate compounds include alkyl (meth)acrylate compounds and aryl (meth)acrylate compounds, with alkyl (meth)acrylate compounds being preferred. The number of carbon atoms in the alkyl group constituting the alkyl (meth)acrylate compound is not particularly limited, and can be, for example, 1 to 24. From the viewpoint of improving dispersibility and battery characteristics, 3 to 20 is preferred, more preferably 4 to 16, and even more preferably 6 to 14. The number of carbon atoms in the aryl group constituting the aryl ester is not particularly limited, and can be, for example, 6 to 24, preferably 6 to 10. In (meth)acrylamide compounds, the nitrogen atom of the amide group can be replaced by an alkyl or aryl group.

[0182] There are no particular limitations on the vinyl monomer used, but vinyl compounds (M2) capable of copolymerizing with (meth)acrylic acid compound (M1) are preferred. Examples include aromatic vinyl compounds such as styrene compounds, vinylnaphthalene compounds, and vinylcarbazole compounds, as well as allyl compounds, vinyl ether compounds, vinyl ester compounds, itaconic acid dialkyl ester compounds, and unsaturated carboxylic anhydrides. Examples of vinyl compounds include "vinyl monomers" as described in Japanese Patent Application Publication No. 2015-88486. Aromatic vinyl compounds are preferred, and styrene compounds are more preferred. Specifically, preferred vinyl compounds (M2) include styrene, methylstyrene, chlorostyrene, trifluoromethylstyrene, and pentafluorostyrene.

[0183] (Meth)acrylic acid compounds (M1) and vinyl compounds (M2) may have substituents. There are no particular limitations on the substituents, and groups selected from substituent Z described later can be cited, preferably in the form of a group not substituted with a fluorine atom.

[0184] The (meth)acrylic acid compound (M1) and the vinyl compound (M2) that are components of the introduced (meth)acrylic acid polymer are preferably compounds represented by the following formula (b-1).

[0185] [Chemical Formula 3]

[0186]

[0187] In the formula, R 1The group represents a hydrogen atom, hydroxyl group, cyano group, halogen atom, alkyl group (preferably with 1 to 24 carbon atoms, more preferably 1 to 12, especially preferably 1 to 6), alkenyl group (preferably with 2 to 24 carbon atoms, more preferably 2 to 12, especially preferably 2 to 6), alkynyl group (preferably with 2 to 24 carbon atoms, more preferably 2 to 12, especially preferably 2 to 6), or aryl group (preferably with 6 to 22 carbon atoms, more preferably 6 to 14). Among these, hydrogen atoms or alkyl groups are preferred, and hydrogen atoms or methyl groups are even more preferred.

[0188] R 2 Represents a hydrogen atom or a substituent. As R 2 The substituents that can be used are not particularly limited, and examples include alkyl (which can be branched, but preferably straight), alkenyl (preferably with 2 to 12 carbon atoms, more preferably 2 to 6, especially preferably 2 or 3), aryl (preferably with 6 to 22 carbon atoms, more preferably 6 to 14), aralkyl (preferably with 7 to 23 carbon atoms, more preferably 7 to 15), and cyano.

[0189] The number of carbon atoms in an alkyl group has the same meaning as the number of carbon atoms in an alkyl group constituting a (meth)acrylate alkyl ester compound, and the preferred range is also the same.

[0190] L 1 The linking group is not particularly limited, and L in the above formula (LF) can be used as an example.

[0191] When L 1 Take -CO-O- or -CO-N(R) N )-base(R N As described above, the compound represented by formula (b-1) above is equivalent to (meth)acrylic acid compound (M1), and otherwise is equivalent to vinyl compound (M2).

[0192] n is 0 or 1, preferably 1. Where, -(L 1 ) n -R 2 In the case of a substituent (e.g., alkyl), set n to 0 and R to 0. 2 Set as a substituent (alkyl).

[0193] In the above formula (b-1), the carbon atom that forms the polymerizable group and is not bonded to R 1 The carbon atom is represented as an unsubstituted carbon atom (H₂C=), but it can have substituents. There are no particular restrictions on the substituents, but examples include R. 1 The above-mentioned groups.

[0194] Furthermore, in formula (b-1), substituents may be present in groups such as alkyl, aryl, alkylene, and arylene, without impairing the effects of the present invention. There are no particular limitations on the substituents; for example, groups selected from substituent Z described later can be cited, preferably those not substituted with fluorine atoms.

[0195] The polymer formed by introducing an adhesive can have macromonomers derived from macromonomers as constituent components. Examples of macromonomers include (based on the above-described method for determining mass-average molecular weight) macromonomers with a number-average molecular weight of 1,000 or more, preferably 3,000 or more. There is no particular upper limit; for example, it can be set to 500,000, preferably 30,000 or less.

[0196] The macromonomer preferably has the aforementioned olefinic unsaturated group and polymer chain. The polymer chain can be made of conventional polymers without particular limitation, but in this invention, polymer chains made of (meth)acrylic acid polymers and polymer chains made of polysiloxanes are preferred. As a polymer chain made of (meth)acrylic acid polymers, it is preferable to have components derived from the aforementioned (meth)acrylic acid compound (M1), components derived from the vinyl compound (M2), and components derived from olefinic unsaturated monomers having the aforementioned fluorine or silicon atoms, particularly components represented by the aforementioned formula (LF) or formula (LS). More preferably, a polymer chain has a (meth)acrylic ester compound and a component represented by the aforementioned formula (LF). As a polymer chain made of polysiloxanes, it is preferable to have components derived from the aforementioned R... S The appropriate material is -(SiR2-O). n - The polymer chain is composed of groups representing the structure. The content of each component in the polymer chain of the macromonomer is not particularly limited and can be appropriately set. For example, the content of the component derived from the (meth)acrylic acid compound (M1) in the polymer chain of the macromonomer is preferably 40-90% by mass, more preferably 50-80% by mass, and even more preferably 60-70% by mass. Similarly, the content of the component represented by formula (LF) or formula (LS) is preferably 10-60% by mass, more preferably 20-50% by mass, and even more preferably 30-40% by mass.

[0197] There are no particular restrictions on the linking groups connecting the olefinic unsaturated group and the polymer chain, but single bonds, ester bonds (-CO-O- group), and amide bonds (-CO-N-R group) are preferred. N )-base(R N As mentioned above), carbamate bonds (-N(R) N )-CO-based(R N As mentioned above), urea bond (-N(R) N )-CO-N(R N)-base(R N Various bonds such as those described above (ether bonds, carbonate bonds (-O-CO- group), disubstituted benzene (phenylene), and linking groups used in synthesis that contain structural parts derived from chain transfer agents, polymerization initiators, etc., or combinations thereof, can be used as linking groups, for example, as the linking groups that can be used as L above. Preferably, they contain -CO-O- group or -CO-N(R) group. N )-base(R N (As described above) and groups derived from the structural portions of chain transfer agents, polymerization initiators, etc. Examples of linking groups include linking groups derived from the constituent components of macromonomers contained in the polymers synthesized in the examples.

[0198] In this invention, examples of macromonomers include those incorporated into the polymers shown below and the polymers synthesized in the examples, as well as those described in Japanese Patent Application Publication No. 2015-088486.

[0199] Adhesives that form polymers with components derived from the macromolecular monomer are called graft polymers.

[0200] The binder forming polymer preferably has constituent components represented by the above formula (LF) or formula (LS) in the main chain or side chain (graft chain).

[0201] When the side chain has a constituent component represented by the above formula (LF), it is preferable that the constituent component is incorporated into the polymer chain of the above macromolecular monomer.

[0202] In the constituent components represented by the above formula (LS), R S For having -(SiR2-O) n When the structure is represented by a group (n is 2 or more), the constituent component is equivalent to a constituent component derived from a macromolecular monomer, and the adhesive forming polymer with the constituent component on the main chain becomes a graft polymer.

[0203] From the viewpoint of being able to bind closely with inorganic solid electrolytes and active substances, thereby improving dispersibility, and further improving the binding between solid particles and the current collector, it is preferable that the binder forming polymer has components derived from (meth)acrylic acid compound (M1), especially components derived from (meth)acrylic ester compound.

[0204] Furthermore, from the viewpoint of improving the elastic modulus of the binder-forming polymer in addition to improving its adhesion to inorganic solid electrolytes and active substances, it is preferable that the binder-forming polymer also has components derived from (meth)acrylonitrile compounds in the (meth)acrylic acid compound (M1).

[0205] Furthermore, from the viewpoint of improving the elastic modulus of the binder-forming polymer, it is preferable that the binder-forming polymer also has components derived from styrene compounds in the vinyl compound.

[0206] There is no particular limitation on the content of each component in the adhesive polymer; it can be appropriately determined by considering surface energy and SP value.

[0207] The content of each component in the vinyl polymer is set within the range below, for example, so that the total content of all components is 100 by mass.

[0208] For example, in vinyl polymers, the content of components derived from vinyl compounds (including components represented by the above formula (LF) or formula (LS)) can also be set to 100% by mass, but is preferably 50 to 90% by mass, more preferably 60 to 80% by mass, and particularly preferably 65 to 75% by mass. The content of components derived from styrene compounds in vinyl compounds is set within the range described above, preferably 55 to 80% by mass, more preferably 60 to 70% by mass.

[0209] In the vinyl polymer, the content of the constituent component derived from the (meth)acrylic acid compound (M1) is set to less than 50% by mass, preferably 0 to 40% by mass, more preferably 5 to 35% by mass. The content of the constituent component derived from the (meth)acrylic acid compound (M1) (excluding the constituent component represented by the above formula (LF) or formula (LS)) is set within the above range, preferably 0 to 40% by mass, more preferably 5 to 35% by mass. Furthermore, the content of the constituent component derived from the (meth)acrylonitrile compound in the (meth)acrylic acid compound (M1) is set within the above range, preferably 0 to 40% by mass, more preferably 5 to 35% by mass.

[0210] The content of the constituent component derived from olefinic unsaturated monomers having fluorine or silicon atoms is preferably 3 to 60% by mass, more preferably 5 to 60% by mass, even more preferably 10 to 50% by mass, and particularly preferably 15 to 40% by mass. The content of the constituent component represented by the above formula (LF) or formula (LS) and incorporated into the main chain of the vinyl polymer is set within the above range, for example preferably 5 to 60% by mass, more preferably 10 to 55% by mass, and even more preferably 15 to 50% by mass.

[0211] The content of the constituent components derived from macromonomers is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, and even more preferably 15 to 35% by mass. Wherein, when the constituent components derived from macromonomers include constituent components derived from olefinic unsaturated monomers having fluorine or silicon atoms in their polymer chains, the content of the constituent components derived from such macromonomers is included in the above-mentioned "content of constituent components derived from olefinic unsaturated monomers having fluorine or silicon atoms".

[0212] The content of each component in the (meth)acrylic acid polymer is set within the range below, for example, so that the total content of all components is 100 by mass.

[0213] For example, the content of the constituent components derived from the (meth)acrylic acid compound (M1) (including the constituent components represented by the above formula (LF) or formula (LS)) can also be set to 100% by mass, for example, preferably 50 to 90% by mass, more preferably 55 to 80% by mass. The content of the constituent components derived from the (meth)acrylic acid compound (M1) (excluding the constituent components represented by the above formula (LF) or formula (LS)) in the (meth)acrylic acid compound (M1) is set within the range that satisfies the above, preferably 35 to 90% by mass, more preferably 50 to 85% by mass, further preferably 55 to 80% by mass, and especially preferably 60 to 70% by mass. Furthermore, the content of the constituent components derived from the (meth)acrylonitrile compound in the (meth)acrylic acid compound (M1) is set within the above range, preferably 5 to 80% by mass, more preferably 10 to 75% by mass, and even more preferably 10 to 50% by mass.

[0214] The content of the constituent components derived from vinyl compounds (excluding the constituent components represented by the above formula (LF) or formula (LS)) is set to 50% by mass or less, preferably 0 to 40% by mass, more preferably 5 to 35% by mass. The content of the constituent components derived from styrene compounds in the vinyl compounds is set within the above range, preferably 0 to 45% by mass, more preferably 10 to 35% by mass.

[0215] The content of the constituent component derived from an olefinically unsaturated monomer having fluorine or silicon atoms is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, and even more preferably 15 to 40% by mass. The content of the constituent component represented by the above formula (LF) or formula (LS) and incorporated into the main chain of the (meth)acrylic acid polymer is set within the above range, for example, preferably 5 to 60% by mass, more preferably 10 to 55% by mass, and even more preferably 15 to 50% by mass.

[0216] The content of the constituent components derived from macromonomers is preferably 5 to 40% by mass, more preferably 10 to 35% by mass, and even more preferably 15 to 30% by mass. Wherein, when the constituent components derived from macromonomers include constituent components derived from olefinic unsaturated monomers having fluorine or silicon atoms in their polymer chains, the content of the constituent components derived from such macromonomers is included in the above-mentioned "content of constituent components derived from olefinic unsaturated monomers having fluorine or silicon atoms".

[0217] Chain polymers (constituent components and raw material compounds) may have substituents. There are no particular limitations on the substituents, but groups selected from substituent Z below are preferred.

[0218] -Substituent Z-

[0219] Examples of alkyl groups include alkyl groups (preferably alkyl groups with 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, tert-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl groups (preferably alkenyl groups with 2 to 20 carbon atoms, such as vinyl, allyl, oleyl, etc.), alkynyl groups (preferably alkynyl groups with 2 to 20 carbon atoms, such as ethynyl, butyrynyl, phenylethynyl, etc.), and cycloalkyl groups (preferably cycloalkyl groups with 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl). 4-Methylcyclohexyl, etc. (When alkyl is used in this specification, it usually indicates that it contains cycloalkyl, but it is described separately here.) aryl (preferably aryl with 6 to 26 carbon atoms, for example, phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), aralkyl (preferably aralkyl with 7 to 23 carbon atoms, for example, benzyl, phenethyl, etc.), heterocyclic (preferably heterocyclic with 2 to 20 carbon atoms, more preferably heterocyclic with a 5 or 6-membered ring having at least one oxygen atom, sulfur atom, and nitrogen atom).

[0220] Heterocyclic groups include aromatic heterocyclic groups and aliphatic heterocyclic groups. Examples include tetrahydropyranyl, tetrahydrofuranyl, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, pyrrolidone, etc.), alkoxy groups (preferably alkoxy groups with 1 to 20 carbon atoms, such as methoxy, ethoxy, isopropoxy, benzyloxy, etc.), aryloxy groups (preferably aryloxy groups with 6 to 26 carbon atoms, such as phenoxy, 1-naphthoxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.; when referred to as aryloxy in this specification, it refers to a group containing an aryloxy group), and heterocyclic groups (in the above...). Groups with -O- groups bonded to heterocyclic groups, alkoxycarbonyl groups (preferably alkoxycarbonyl groups with 2 to 20 carbon atoms, such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl, dodecyloxycarbonyl, etc.), aryloxycarbonyl groups (preferably aryloxycarbonyl groups with 6 to 26 carbon atoms, such as phenoxycarbonyl, 1-naphthoxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), heterocyclic oxycarbonyl groups (groups formed by bonding -O-CO- groups to the above heterocyclic groups), and amino groups (preferably amino, alkylamino, or aromatic amino groups containing 0 to 20 carbon atoms). For example, amino (-NH2), N,N-dimethylamino, N,N-diethylamino, N-ethylamino, aniline, etc.), aminosulfonyl (preferably aminosulfonyl with 0 to 20 carbon atoms, such as N,N-dimethylaminosulfonyl, N-phenylaminosulfonyl, etc.), acyl (including alkyl carbonyl, alkenyl carbonyl, alkynyl carbonyl, aryl carbonyl, heterocyclic carbonyl, preferably acyl with 1 to 20 carbon atoms, such as acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acrylyl, methacrylyl, crotonyl, benzoyl, naphthyl Acyloxy groups (including alkyl carbonyloxy, alkenyl carbonyloxy, alkynyl carbonyloxy, aryl carbonyloxy, heterocyclic carbonyloxy, preferably acyloxy groups with 1 to 20 carbon atoms, such as acetoxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyloxy, acryloxy, methacryloxy, crotonyloxy, benzoyloxy, naphthyloxy, nicotinoxy, etc.), aromatic acyloxy groups (preferably aromatic acyloxy groups with 7 to 23 carbon atoms, such as benzoyloxy, etc.), and carbamoyl groups (preferably carbamoyl groups with 1 to 20 carbon atoms, such as N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), amide (preferably amide with 1 to 20 carbon atoms, such as acetamido, benzoylamino, etc.), alkylthio (preferably alkylthio with 1 to 20 carbon atoms, such as methylthio, ethylthio, isopropylthio, benzylthio, etc.), arylthio (preferably arylthio with 6 to 26 carbon atoms, such as phenylthio, 1-naphthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), heterocyclic thio (a group with -S- group bonded to the above heterocyclic group), alkylsulfonyl (preferably alkylsulfonyl with 1 to 20 carbon atoms, such as methylsulfonyl, ethylsulfonyl, etc.), arylsulfonyl (preferably arylsulfonyl with 6 to 22 carbon atoms, such as benzylsulfonyl, etc.). Alkylsilyl groups (preferably alkylsilyl groups with 1 to 20 carbon atoms, such as monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), arylsilyl groups (preferably arylsilyl groups with 6 to 42 carbon atoms, such as triphenylsilyl, etc.), alkoxysilyl groups (preferably alkoxysilyl groups with 1 to 20 carbon atoms, such as monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.), aryloxysilyl groups (preferably aryloxysilyl groups with 6 to 42 carbon atoms, such as triphenoxysilyl, etc.), and phosphoryl groups (preferably phosphoric acid groups with 0 to 20 carbon atoms, such as -OP(=O)(R, P )2) Phosphonyl group (preferably a phosphonyl group with 0 to 20 carbon atoms, for example, -P(=O)(R P )2) Oxyphosphin group (preferably oxyphosphin group with 0 to 20 carbon atoms, for example, -P(R P 2) Phosphonic acid group (preferably a phosphonic acid group with 0 to 20 carbon atoms, for example, -PO(OR) P 2) Sulfonate (sulfonic acid group), carboxyl group, hydroxyl group, thioalkyl group, cyano group, halogen atom (e.g., fluorine atom, chlorine atom, bromine atom, iodine atom, etc.).

[0221] R P It is a hydrogen atom or a substituent (preferably a group selected from substituent Z).

[0222] Furthermore, each of the groups listed in these substituents Z can be further replaced by the aforementioned substituents Z.

[0223] The aforementioned alkyl, alkylene, alkenyl, alkenylene, ynyl and / or ynylene groups can be cyclic or chain-like, and can be straight-chain or branched.

[0224] Chain polymers can be synthesized by selecting feedstock compounds using known methods and by polymerizing the feedstock compounds.

[0225] As specific examples of polymers formed by adhesives, in addition to those synthesized in the examples, the following polymers can be listed, but the present invention is not limited to these. In each specific example, the number marked to the lower right of the constituent ingredient indicates the content of the polymer, and the unit is mass%. In addition, in the following specific examples, Me represents methyl, and "(constituent)-b-(constituent)" indicates a block polymer composed of blocks of each constituent ingredient.

[0226] [Chemical Formula 4]

[0227]

[0228] The binder contained in the inorganic solid electrolyte composition may be one type or two or more types.

[0229] There are no particular limitations on the content of the inorganic solid electrolyte composition in the adhesive. From the viewpoints of dispersibility, ionic conductivity, and adhesion, the content of the solid component in 100% by mass is preferably 0.1 to 10.0% by mass, more preferably 0.5 to 9.0% by mass, and even more preferably 1.0 to 8.0% by mass. When the inorganic solid electrolyte composition contains an active substance, the content of the solid component in the adhesive in 100% by mass is preferably 0.1 to 10.0% by mass, more preferably 0.2 to 5.0% by mass, even more preferably 0.3 to 4.0% by mass, and particularly preferably 0.5 to 2.0% by mass.

[0230] In this invention, the mass ratio of the total mass (total amount) of the inorganic solid electrolyte and the active material to the mass of the binder in 100% by mass of the solid component [(mass of inorganic solid electrolyte + mass of active material) / (total mass of binder)] is preferably in the range of 1,000 to 1. Furthermore, this ratio is more preferably 500 to 2, and even more preferably 100 to 10.

[0231] <Dispersion Medium>

[0232] As a dispersion medium contained in an inorganic solid electrolyte composition, any organic compound that appears liquid in the environment of use can be used. Examples include various organic solvents, specifically alcohols, ethers, amides, amines, ketones, aromatics, aliphatic compounds, nitriles, and esters.

[0233] The dispersion medium can be a nonpolar dispersion medium (hydrophobic dispersion medium) or a polar dispersion medium (hydrophilic dispersion medium). From the viewpoint of exhibiting excellent dispersibility, a nonpolar dispersion medium is preferred. A nonpolar dispersion medium generally refers to a medium with low affinity for water; however, in this invention, examples include ester compounds, ketone compounds, ether compounds, aromatic compounds, and aliphatic compounds.

[0234] Examples of alcohol compounds include, for example, methanol, ethanol, 1-propanol, 2-propanol, 2-butanol, ethylene glycol, propylene glycol, glycerol, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, 2-methyl-2,4-pentanediol, 1,3-butanediol, and 1,4-butanediol.

[0235] Examples of ether compounds include alkylene glycols (diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, etc.), alkylene glycol monoalkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, etc.), alkylene glycol dialkyl ethers (ethylene glycol dimethyl ether, etc.), dialkyl ethers (dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, etc.), and cyclic ethers (tetrahydrofuran, dioxanes (including 1,2-, 1,3- and 1,4- isomers, etc.)).

[0236] Examples of amide compounds include, for example, N,N-dimethylformamide, N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-2-imidazolinone, ε-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropaneamide, hexamethylphosphoric triamide, etc.

[0237] Examples of amine compounds include triethylamine, diisopropylethylamine, and tri-n-butylamine.

[0238] Examples of ketone compounds include acetone, methyl ethyl ketone, methyl isobutyl ketone (MIBK), cyclopentanone, cyclohexanone, cycloheptanone, dipropyl ketone, dibutyl ketone, diisopropyl ketone, diisobutyl ketone (DIBK), isobutylpropyl ketone, sec-butylpropyl ketone, pentylpropyl ketone, butylpropyl ketone, etc.

[0239] Examples of aromatic compounds include, for example, benzene, toluene, xylene, and perfluorotoluene.

[0240] Examples of aliphatic compounds include hexane, heptane, octane, nonane, decane, dodecane, cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, cyclooctane, decahydronaphthalene, paraffin wax, gasoline, naphtha, kerosene, and light oil.

[0241] Examples of nitrile compounds include acetonitrile, propionitrile, and isobutyronitrile.

[0242] Examples of ester compounds include, for example, ethyl acetate, propyl acetate, butyl acetate, ethyl butyrate, propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, butyl valerate, pentyl valerate, ethyl isobutyrate, propyl isobutyrate, isopropyl isobutyrate, isobutyl isobutyrate, propyl neovalerate, isopropyl neovalerate, butyl neovalerate, isobutyl neovalerate, etc.

[0243] In this invention, ether compounds, ketone compounds, aromatic compounds, aliphatic compounds, and ester compounds are preferred, and ester compounds, ketone compounds, or ether compounds are more preferred.

[0244] There is no particular limitation on the number of carbon atoms in the compound constituting the dispersion medium, but it is preferably 2 to 30, more preferably 4 to 20, even more preferably 6 to 15, and especially preferably 7 to 12.

[0245] From the perspective of improving affinity with adhesives and enhancing the dispersibility of solid particles, for example, the SP value (MPa) of the dispersion medium. 1 / 2 The SP value is preferably 14 to 24, more preferably 15 to 22, and even more preferably 16 to 20. There is no particular limitation on the absolute value of the difference between the SP value of the polymer formed by the dispersion medium and the binder. From the viewpoint of further improving the dispersibility of the binder in the dispersion medium, it is preferably 3 or less, more preferably 0 to 2, and even more preferably 0 to 1.

[0246] The SP value of the dispersion medium is set to be the SP value calculated by the Hoy method above, converted to MPa. 1 / 2 The SP value is obtained as follows. When the inorganic solid electrolyte composition contains two or more dispersion media, the SP value of the dispersion media refers to the SP value of the entire dispersion media, and is set as the sum of the products of the SP value of each dispersion media and its mass fraction. Specifically, except that the SP value of each dispersion media is used instead of the SP value of the constituent components, it is calculated in the same way as the SP value of the polymer described above.

[0247] The following shows the SP values ​​(units omitted) of the main dispersion media.

[0248] MIBK (18.4), diisopropyl ether (16.8), dibutyl ether (17.9), diisobutyl ketone (17.9), DIBK (17.9), butyl butyrate (18.6), butyl acetate (18.9), toluene (18.5), ethylcyclohexane (17.1), cyclooctane (18.8), isobutyl ethyl ether (15.3), N-methylpyrrolidone (NMP, SP value: 25.4), perfluorotoluene (SP value: 13.4)

[0249] The boiling point of the dispersion medium at atmospheric pressure (1 atmosphere) is preferably 50°C or higher, more preferably 70°C or higher. The upper limit is preferably 250°C or lower, and even more preferably 220°C or lower.

[0250] The dispersion medium contained in the inorganic solid electrolyte composition may be one type or two or more types.

[0251] In this invention, the content of the dispersion medium in the inorganic solid electrolyte composition is not particularly limited and can be appropriately set. For example, the inorganic solid electrolyte composition preferably contains 20 to 80% by mass, more preferably 30 to 70% by mass, and particularly preferably 40 to 60% by mass.

[0252] <Active Substances>

[0253] The inorganic solid electrolyte composition of the present invention may also contain an active material capable of intercalating or deintercalating ions of metals belonging to Group 1 or Group 2 of the periodic table. Examples of active materials, including positive electrode active materials and negative electrode active materials, will be described below.

[0254] In this invention, an inorganic solid electrolyte composition containing an active material (positive electrode active material or negative electrode active material) is sometimes referred to as an electrode composition (positive electrode composition or negative electrode composition).

[0255] (Positive electrode active material)

[0256] The positive electrode active material is preferably a positive electrode active material capable of reversibly inserting and deintercalating lithium ions. There are no particular restrictions as long as the material has the above-mentioned characteristics, and it can be a transition metal oxide of the decomposition battery or an element that can recombine with Li, such as sulfur.

[0257] Among them, transition metal oxides are preferred as positive electrode active materials, and more preferably materials containing the transition metal element M. a A transition metal oxide (selected from one or more elements including Co, Ni, Fe, Mn, Cu, and V). Furthermore, element M may also be mixed into this transition metal oxide. b (Elements of Group 1(Ia) and Group 2(IIa) of the periodic table, excluding lithium, and elements such as Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, and B). As a mixing amount, it is preferable to be relative to the transition metal element M. a The amount (per 100 mol%) is 0–30 mol%. More preferably, it is Li / M a They are synthesized by mixing in a molar ratio of 0.3 to 2.2.

[0258] Specific examples of transition metal oxides include (MA) transition metal oxides with a layered rock salt structure, (MB) transition metal oxides with a spinel structure, (MC) lithium-containing transition metal phosphate compounds, (MD) lithium-containing transition metal halophosphate compounds, and (ME) lithium-containing transition metal silicate compounds.

[0259] Specific examples of transition metal oxides (MA) with layered rock salt-type structures include LiCoO2 (lithium cobalt oxide [LCO]), LiNi2O2 (lithium nickel oxide), and LiNi 0.85 Co 0.10 Al 0.05 O2 (lithium nickel cobalt aluminum oxide [NCA]), LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 (lithium nickel manganese cobalt oxide [NMC]) and LiNi 0.5 Mn 0.5 O2 (lithium manganese nickel oxide).

[0260] Specific examples of transition metal oxides (MB) with spinel-type structures include LiMn2O4 (LMO), LiCoMnO4, Li2FeMn3O8, Li2CuMn3O8, Li2CrMn3O8, and Li2NiMn3O8.

[0261] Examples of lithium-containing transition metal phosphates (MC) include olivine-type iron phosphates such as LiFePO4 and Li3Fe2(PO4)3, iron pyrophosphates such as LiFeP2O7, cobalt phosphates such as LiCoPO4, and monoclinic NASICON-type vanadium phosphates such as Li3V2(PO4)3 (lithium vanadium phosphate).

[0262] Examples of lithium-containing transition metal halophosphates (MD) include, for example, iron fluorophosphates such as Li2FePO4F, manganese fluorophosphates such as Li2MnPO4F, and cobalt fluorophosphates such as Li2CoPO4F.

[0263] Examples of lithium-containing transition metal silicate compounds include, for example, Li2FeSiO4, Li2MnSiO4, and Li2CoSiO4.

[0264] In this invention, (MA) is preferably a transition metal oxide having a layered rock salt structure, and more preferably LCO or NMC.

[0265] The shape of the positive electrode active material is not particularly limited, but particulate form is preferred. The particle size (volume average particle size) of the positive electrode active material is not particularly limited. For example, it can be set to 0.1–50 μm. The particle size of the positive electrode active material can be measured in the same manner as the particle size of the aforementioned inorganic solid electrolyte. To achieve the desired particle size, a conventional pulverizer or classifier is used. For example, a mortar, ball mill, sand mill, vibratory ball mill, satellite ball mill, planetary ball mill, and rotary airflow jet mill or sieve can be suitably used. During pulverization, wet pulverization with a dispersion medium such as water or methanol can also be appropriately performed. To achieve the desired particle size, classification is preferred. Classification is not particularly limited and can be performed using sieves, air classifiers, etc. Both dry and wet classification can be used.

[0266] Positive active materials obtained by sintering can also be used after being cleaned with water, acidic aqueous solutions, alkaline aqueous solutions, and organic solvents.

[0267] One type of positive electrode active material can be used alone, or two or more types can be used in combination.

[0268] The content of the positive electrode active material in the inorganic solid electrolyte composition is not particularly limited, but is preferably 10-97% by mass, more preferably 30-95% by mass, further preferably 40-93% by mass, and especially preferably 50-90% by mass in 100% by mass of solid components.

[0269] (Negative electrode active material)

[0270] The negative electrode active material is an active material capable of intercalating and deintercalating ions of metals belonging to Group 1 or Group 2 of the periodic table, preferably an active material capable of reversibly intercalating and deintercalating lithium ions. There are no particular limitations on the material as long as it possesses the aforementioned properties; examples include carbonaceous materials, metal oxides, metal composite oxides, lithium monomers, lithium alloys, and negative electrode active materials capable of forming alloys with lithium (alloyable). From a reliability perspective, carbonaceous materials, metal composite oxides, or lithium monomers are preferred. From the viewpoint of maximizing the capacity of all-solid-state secondary batteries, active materials capable of alloying with lithium are preferred. Because the solid particles in the constituent layer formed by the solid electrolyte composition of the present invention are firmly bonded to each other, a negative electrode active material capable of forming alloys with lithium can be used as the negative electrode active material. This increases the capacity of the all-solid-state secondary battery and extends its lifespan.

[0271] Carbonaceous materials used as negative electrode active materials refer to materials that are essentially composed of carbon. Examples include carbonaceous materials produced by sintering petroleum asphalt, carbon black such as acetylene black (AB), graphite (natural graphite, vapor-grown graphite, and other artificial graphite), and various synthetic resins such as PAN (polyacrylonitrile) resins or furfuryl alcohol resins. Furthermore, examples include various types of carbon fibers such as PAN-based carbon fibers, cellulose-based carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, dehydrated PVA (polyvinyl alcohol)-based carbon fibers, lignin carbon fibers, glassy carbon fibers, and activated carbon fibers, as well as mesophase microspheres, graphite whiskers, and planar graphite.

[0272] These carbonaceous materials are classified into non-graphitized carbonaceous materials (also known as hard carbon) and graphite-based carbonaceous materials based on the degree of graphitization. Furthermore, the carbonaceous materials preferably possess the facet spacing or density and crystallite size described in Japanese Patent Application Publication Nos. 62-22066, 2-6856, and 3-45473. The carbonaceous material need not be a single material; mixtures of natural and artificial graphite as described in Japanese Patent Application Publication No. 5-90844, or coated graphite as described in Japanese Patent Application Publication No. 6-4516, etc., can also be used.

[0273] As a carbonaceous material, hard carbon or graphite is preferred, with graphite being more preferred.

[0274] As oxides of metals or half-metals suitable as negative electrode active materials, there are no particular limitations as long as they are oxides capable of absorbing and releasing lithium. Examples include oxides of metal elements (metal oxides), composite oxides of metal elements, or composite oxides of metal elements and half-metal elements (collectively referred to as metal composite oxides), and oxides of half-metal elements (half-metal oxides). Among these oxides, amorphous oxides are preferred, and further preferred are chalcogenides, products of the reaction between metal elements and elements of Group 16 of the periodic table. In this invention, a half-metal element refers to an element exhibiting intermediate properties between a metal element and a non-half-metal element, typically including six elements: boron, silicon, germanium, arsenic, antimony, and tellurium, and further including three elements: selenium, polonium, and astatine. Furthermore, amorphous refers to a material having a broad scattering band with vertices in the region of 20° to 40° at 2θ values ​​using CuKα X-ray diffraction, and may also have crystalline diffraction lines. The strongest intensity of the crystalline diffraction lines appearing in the region of 40° to 70° at a 2θ value is preferably 100 times or less than the intensity of the diffraction line at the apex of the broad scattering band appearing in the region of 20° to 40° at a 2θ value, more preferably 5 times or less, and especially preferably a non-crystalline diffraction line.

[0275] Among the compounds comprising the aforementioned amorphous oxides and chalcogenides, amorphous oxides of half-metallic elements or the aforementioned chalcogenides are more preferred, and (composite) oxides or chalcogenides comprising one or more elements selected from groups 13(IIIB) to 15(VB) of the periodic table (e.g., Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi) are particularly preferred. Specific examples of preferred amorphous oxides and chalcogenides include, for example, Ga₂O₃, GeO, PbO, PbO₂, Pb₂O₃, Pb₂O₄, Pb₃O₄, Sb₂O₄, Sb₂O₈Bi₂O₃, Sb₂O₈Si₂O₃, Sb₂O₅, Bi₂O₃, Bi₂O₄, GeS, PbS, PbS₂, Sb₂S₃, or Sb₂S₅.

[0276] As a negative electrode active material that can be used with amorphous oxides centered on Sn, Si, and Ge, carbonaceous materials, lithium monomers, lithium alloys, and negative electrode active materials that can be alloyed with lithium are preferred examples.

[0277] From the viewpoint of high current density charge and discharge characteristics, oxides of metal or half-metal elements, especially metal (composite) oxides and the aforementioned chalcogenides, preferably contain at least one of titanium and lithium as constituent components. Examples of lithium-containing metal composite oxides (lithium composite metal oxides) include composite oxides of lithium oxide with the aforementioned metal (composite) oxides or chalcogenides; more specifically, Li₂SnO₂ can be cited.

[0278] Negative electrode active materials, such as metal oxides, are preferably those containing titanium (titanium oxide). Specifically, due to Li4Ti5O 12 Lithium titanate (LTO) exhibits minimal volume change during lithium ion adsorption and deintercalation, resulting in excellent rapid charge and discharge characteristics. It is preferred in terms of both suppressing electrode degradation and improving the lifespan of lithium-ion secondary batteries.

[0279] There are no particular restrictions on the lithium alloy used as the negative electrode active material, as long as it is an alloy commonly used as the negative electrode active material in secondary batteries; for example, lithium-aluminum alloy can be cited.

[0280] There are no particular limitations on the negative electrode active material that can form an alloy with lithium, as long as it is a negative electrode active material commonly used in secondary batteries. Such active materials experience significant expansion and contraction during charging and discharging in all-solid-state secondary batteries, which accelerates the decline in cycle characteristics. However, the inorganic solid electrolyte composition of the present invention contains the aforementioned polymer binder, thus suppressing the decline in cycle characteristics. Examples of such active materials include (negative electrode) active materials (alloys, etc.) containing silicon or tin, various metals such as Al and In, with silicon-containing active materials (active materials containing silicon) preferred to achieve higher battery capacity. More preferably, active materials containing silicon with a silicon content of 50 mol% or more of all constituent elements are also preferred.

[0281] Generally, negative electrodes containing these active materials (e.g., Si negative electrodes containing silicon-containing active materials, Sn negative electrodes containing tin-containing active materials, etc.) can absorb more Li ions compared to carbon negative electrodes (graphite and acetylene black, etc.). That is, the amount of Li ions retained per unit mass increases. Therefore, the battery capacity (energy density) can be increased. Consequently, it has the advantage of extending battery operating time.

[0282] Examples of silicon-containing active materials include silicon materials such as Si and SiOx (0 < x ≤ 1), as well as silicon-containing alloys (e.g., LaSi2, VSi2, La-Si, Gd-Si, Ni-Si) or structured active materials (e.g., LaSi2 / Si) containing elements such as titanium, vanadium, chromium, manganese, nickel, copper, and lanthanum. Additionally, active materials containing silicon elements such as SnSiO3 and SnSiS3, and tin elements, are also included. Furthermore, SiOx can be used as a negative electrode active material (a half-metal oxide) itself, and since Si is generated through the operation of an all-solid-state secondary battery, it can be used as a negative electrode active material (its precursor material) that can be alloyed with lithium.

[0283] Examples of anode active materials containing tin include those containing Sn, SnO, SnO2, SnS, SnS2, and the aforementioned silicon and tin elements. Furthermore, composite oxides with lithium oxide, such as Li2SnO2, can also be cited.

[0284] In this invention, the above-mentioned negative electrode active material can be used without particular limitation. However, from the viewpoint of battery capacity, it is preferable to use a negative electrode active material that can be alloyed with lithium. More preferably, it is the above-mentioned silicon material or silicon-containing alloy (an alloy containing silicon element). It is even more preferably to contain silicon (Si) or a silicon-containing alloy.

[0285] As a determination method, inductively coupled plasma (ICP) emission spectroscopy can be used. As a simple method, the chemical formula of the compound obtained by the above-mentioned firing method can be calculated from the mass difference of the powder before and after firing.

[0286] The shape of the negative electrode active material is not particularly limited, but it is preferably particulate. The volume average particle size of the negative electrode active material is not particularly limited, but is preferably 0.1–60 μm. The volume average particle size of the negative electrode active material can be measured in the same manner as the particle size of the inorganic solid electrolyte described above. To achieve the specified particle size, a conventional pulverizer or classifier is used, similar to that used for the positive electrode active material.

[0287] The above-mentioned negative electrode active material can be used alone or in combination of two or more.

[0288] There is no particular limitation on the content of the negative electrode active material in the inorganic solid electrolyte composition. In 100% by mass of solid components, it is preferably 10 to 90% by mass, more preferably 20 to 85% by mass, more preferably 30 to 80% by mass, and even more preferably 40 to 75% by mass.

[0289] In this invention, when the negative electrode active material layer is formed by charging a secondary battery, ions belonging to Group 1 or Group 2 of the periodic table metal generated within the all-solid-state secondary battery can be used instead of the aforementioned negative electrode active material. By bonding these ions with electrons and depositing them as metal, the negative electrode active material layer can be formed.

[0290] (Coating of active substances)

[0291] The surfaces of both the positive and negative electrode active materials can be coated with different metal oxides. Examples of surface coating agents include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si, or Li. Specifically, examples include spinel titanate, tantalum oxides, niobium oxides, and lithium niobate compounds; for instance, Li₄Ti₅O₅ can be used. 12 , Li2Ti2O5, LiTaO3, LiNbO3, LiAlO2, Li2ZrO3, Li2WO4, Li2TiO3, Li2B4O7, Li3PO4, Li2MoO4, Li3BO3, LiBO2, Li2CO3, Li2SiO3, SiO2, TiO2, ZrO2, Al2O3, B2O3, etc.

[0292] Furthermore, the electrode surface containing positive or negative active materials can be surface-treated with sulfur or phosphorus.

[0293] Furthermore, the particle surfaces of the positive or negative active materials can be surface-treated by photochemical rays or active gases (such as plasma) before and after the aforementioned surface coating.

[0294] <Conductive additives>

[0295] The inorganic solid electrolyte composition of the present invention preferably contains a conductive additive, for example, a silicon-containing active material as a negative electrode active material is used in combination with the conductive additive.

[0296] There are no particular restrictions on the conductive additives used; any conductive additives known to be used as conductive additives can be used. For example, they can be graphite materials such as natural graphite and artificial graphite, carbon black such as acetylene black, Ketjen black, and furnace black, amorphous carbon such as needle coke, carbon fiber materials such as vapor-grown carbon fibers or carbon nanotubes, carbonaceous materials such as graphene or fullerene, metal powders such as copper and nickel, metal fibers, or conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyphenylene derivatives.

[0297] In this invention, when active materials and conductive additives are used in combination, the conductive additives that do not produce the insertion and extraction of metal ions (preferably Li ions) belonging to Group 1 or Group 2 of the periodic table during battery charging and discharging, and do not function as active materials, are classified as conductive additives. Therefore, among conductive additives, those that can function as active materials in the active material layer during battery charging and discharging are classified as active materials rather than conductive additives. Whether an additive functions as an active material during battery charging and discharging is determined by its combination with active materials, rather than by a general rule.

[0298] The conductive additive may contain one type or two or more types.

[0299] There are no particular restrictions on the shape of the conductive additive, but it is preferably in particulate form.

[0300] When the inorganic solid electrolyte composition of the present invention contains a conductive additive, the content of the conductive additive in the inorganic solid electrolyte composition is preferably 0 to 10% by mass of 100% by mass of the solid component.

[0301] <Lithium Salts>

[0302] The inorganic solid electrolyte composition of the present invention preferably also contains a lithium salt (supporting electrolyte).

[0303] As a lithium salt, the lithium salt commonly used in this product is preferred, and there are no particular restrictions. For example, the lithium salt described in paragraphs 0082 to 0085 of Japanese Patent Application Publication No. 2015-088486 is preferred.

[0304] When the inorganic solid electrolyte composition of the present invention contains a lithium salt, the content of the lithium salt relative to 100 parts by weight of the solid electrolyte is preferably 0.1 parts by weight or more, more preferably 5 parts by weight or more. As an upper limit, it is preferably 50 parts by weight or less, more preferably 20 parts by weight or less.

[0305] <Dispersant>

[0306] In the inorganic solid electrolyte composition of the present invention, the aforementioned polymer binder also functions as a dispersant; therefore, it may or may not contain any dispersant other than the polymer binder. As a dispersant, a dispersant commonly used in all-solid-state secondary batteries can be appropriately selected. Typically, compounds suitable for particle adsorption, steric hindrance, and / or electrostatic repulsion are appropriately used.

[0307] <Other Additives>

[0308] The inorganic solid electrolyte composition of the present invention can appropriately contain ionic liquids, thickeners, crosslinking agents (substances that undergo crosslinking reactions via free radical polymerization, condensation polymerization, or ring-opening polymerization, etc.), polymerization initiators (substances that generate acids or free radicals through heat or light, etc.), defoamers, homogenizers, dehydrating agents, antioxidants, etc., as other components besides those mentioned above. The ionic liquid is a liquid contained to further improve ionic conductivity, and known liquids can be used without particular limitation. Furthermore, it can contain polymers other than the aforementioned binder-forming polymers, commonly used adhesives, etc.

[0309] <Preparation of Inorganic Solid Electrolyte Compositions>

[0310] The inorganic solid electrolyte composition of the present invention can be prepared, for example, by mixing an inorganic solid electrolyte, the aforementioned polymer binder, a dispersion medium, preferably a conductive additive, and a suitable lithium salt, and any other components, as a mixture, preferably as a slurry, using various commonly used mixers. In the case of the electrode composition, an active material is further mixed in.

[0311] There are no particular limitations on the mixing method; any known mixer, such as a ball mill, bead mill, planetary mixer, scraper mixer, roller mill, kneader, disc mill, rotary-revolutionary mixer, or narrow-gap disperser, can be used. The components can be mixed all at once or sequentially. There are no particular limitations on the mixing environment; dry air or inert gas conditions are acceptable. Furthermore, there are no particular limitations on the mixing conditions, which can be appropriately set.

[0312] [Sheets for all-solid-state rechargeable batteries]

[0313] The sheet material for all-solid-state secondary batteries of the present invention is a sheet-shaped molded body capable of forming the constituent layers of an all-solid-state secondary battery, and includes various forms depending on its application. For example, sheets preferably used for solid electrolyte layers (also called solid electrolyte sheets for all-solid-state secondary batteries) and sheets preferably used for electrodes or laminates of electrodes and solid electrolyte layers (electrode sheets for all-solid-state secondary batteries) are examples. In the present invention, these various sheets are collectively referred to as sheets for all-solid-state secondary batteries.

[0314] In this invention, each layer constituting the sheet for all-solid-state secondary batteries can be a single-layer structure or a multi-layer structure.

[0315] In the sheet for all-solid-state secondary batteries, the solid electrolyte layer or the active material layer on the substrate is formed from the inorganic solid electrolyte composition of the present invention. Therefore, this sheet for all-solid-state secondary batteries suppresses degradation caused by moisture, and by appropriately peeling off the substrate to serve as the solid electrolyte layer, active material layer, or electrode of the all-solid-state secondary battery, the cycle characteristics of the all-solid-state secondary battery can be improved, thereby improving ionic conductivity even in low-temperature environments. In particular, when the electrode sheet for all-solid-state secondary batteries is assembled as an electrode into an all-solid-state secondary battery, the cycle characteristics can be further improved because the active material layer is firmly bonded to the current collector.

[0316] The solid electrolyte sheet for all-solid-state secondary batteries of the present invention can be any sheet having a solid electrolyte layer. It can be a sheet with the solid electrolyte layer formed on a substrate, or it can be a sheet without a substrate, formed from the solid electrolyte layer (a sheet obtained by peeling off the substrate). The solid electrolyte sheet for all-solid-state secondary batteries may have other layers besides the solid electrolyte layer. Examples of other layers include a protective layer (release sheet), a current collector, and a coating. The solid electrolyte layer of the solid electrolyte sheet for all-solid-state secondary batteries is preferably formed from the inorganic solid electrolyte composition of the present invention. The content of each component in this solid electrolyte layer is not particularly limited; the preferred meaning is the same as the meaning of the content of each component in the solid component of the inorganic solid electrolyte composition of the present invention. The layer thickness of each layer constituting the solid electrolyte sheet for all-solid-state secondary batteries is the same as the layer thickness described later in the description of all-solid-state secondary batteries.

[0317] As for the substrate, there are no particular limitations as long as it is a substrate capable of supporting the solid electrolyte layer. Examples include sheet-like materials (plate-like bodies) such as those described in the current collector section (described later), organic materials, and inorganic materials. Examples of organic materials include various polymers, specifically polyethylene terephthalate, polypropylene, polyethylene, and cellulose. Examples of inorganic materials include, for example, glass and ceramics.

[0318] The electrode sheet for all-solid-state secondary batteries of the present invention (also simply referred to as "electrode sheet") can be any electrode sheet having an active material layer. It can be a sheet with the active material layer formed on a substrate (current collector), or a sheet formed from the active material layer without a substrate (a sheet obtained by peeling off the substrate). The electrode sheet is typically a sheet having a current collector and an active material layer, but it also includes forms having a current collector, an active material layer, and a solid electrolyte layer in sequence, and forms having a current collector, an active material layer, a solid electrolyte layer, and an active material layer in sequence. The solid electrolyte layer and active material layer of the electrode sheet are preferably formed from the inorganic solid electrolyte composition of the present invention. The content of each component in the solid electrolyte layer or active material layer is not particularly limited, and the preferred meaning has the same meaning as the content of each component in the solid component of the inorganic solid electrolyte composition (electrode composition) of the present invention. The layer thickness of each layer constituting the electrode sheet of the present invention is the same as the layer thickness described later in the description of all-solid-state secondary batteries. The electrode sheet may have the other layers mentioned above.

[0319] In the all-solid-state secondary battery sheet of the present invention, at least one of the solid electrolyte layer and the active material layer is formed from the inorganic solid electrolyte composition of the present invention. Therefore, the all-solid-state secondary battery sheet of the present invention suppresses degradation caused by moisture and possesses a constituent layer with low resistance and resistance to degradation even at low temperatures. By using this constituent layer as the constituent layer of the all-solid-state secondary battery, excellent cycle characteristics and low resistance (high conductivity) of the all-solid-state secondary battery can be achieved. In particular, in the all-solid-state secondary battery electrode sheet and the all-solid-state secondary battery in which the active material layer is formed from the inorganic solid electrolyte composition of the present invention, the active material layer and the current collector exhibit strong adhesion, further improving cycle characteristics.

[0320] Furthermore, when the all-solid-state secondary battery sheet has a layer other than the active material layer or the solid electrolyte layer formed by the manufacturing method of the all-solid-state secondary battery sheet of the present invention, this layer can be made of a material manufactured by conventional methods using known materials.

[0321] [Manufacturing Method of Sheets for All-Solid-State Secondary Batteries]

[0322] The manufacturing method of the all-solid-state secondary battery sheet of the present invention is not particularly limited, and it can be manufactured by forming the above-mentioned layers using the inorganic solid electrolyte composition of the present invention. For example, a preferred method is to form a layer (coated and dried layer) composed of the inorganic solid electrolyte composition by film formation (coating and drying) on ​​a substrate or current collector (which may be via another layer). This allows the production of an all-solid-state secondary battery sheet having a substrate or current collector and a coated and dried layer. In particular, when the all-solid-state secondary battery sheet is produced by film formation of the inorganic solid electrolyte composition of the present invention on a current collector, the adhesion between the current collector and the active material layer becomes stronger. Here, the coated and dried layer refers to a layer formed by coating the inorganic solid electrolyte composition of the present invention and drying the dispersion medium (i.e., a layer formed using the inorganic solid electrolyte composition of the present invention, and with the dispersion medium removed from the inorganic solid electrolyte composition of the present invention). The dispersion medium may remain in the active material layer and the coated and dried layer as long as it does not impair the effects of the present invention; the residual amount can be, for example, 3% by mass or less in each layer.

[0323] In the manufacturing method of the all-solid-state secondary battery sheet of the present invention, each step such as coating and drying will be described in the following manufacturing method of the all-solid-state secondary battery.

[0324] In the method for manufacturing the sheet material for all-solid-state secondary batteries of the present invention, the coated and dried layer obtained in the above manner can also be pressurized. The pressurization conditions, etc., will be explained in the manufacturing method for all-solid-state secondary batteries described later.

[0325] Furthermore, in the manufacturing method of the all-solid-state secondary battery sheet of the present invention, it is also possible to peel off the substrate, protective layer (especially the sheet), etc.

[0326] [All-solid-state rechargeable battery]

[0327] The all-solid-state secondary battery of the present invention comprises a positive electrode active material layer, a negative electrode active material layer opposite to the positive electrode active material layer, and a solid electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer. The all-solid-state secondary battery of the present invention is only required to have a structure with a solid electrolyte layer between the positive electrode active material layer and the negative electrode active material layer; other structures are not particularly limited, for example, known structures related to all-solid-state secondary batteries can be used. The positive electrode active material layer is preferably formed on a positive electrode current collector and constitutes the positive electrode. The negative electrode active material layer is preferably formed on a negative electrode current collector and constitutes the negative electrode.

[0328] At least one of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer is formed by the inorganic solid electrolyte composition of the present invention. Preferably, the solid electrolyte layer or at least one of the negative electrode active material layer and the positive electrode active material layer is formed by the inorganic solid electrolyte composition of the present invention. The all-solid-state secondary battery of the present invention, formed by at least one of the constituent layers being the inorganic solid electrolyte composition of the present invention, exhibits excellent cycle characteristics, does not compromise the high ionic conductivity at room temperature, and exhibits sufficient ionic conductivity at low temperature.

[0329] In this invention, it is also a preferred embodiment that all layers are formed from the inorganic solid electrolyte composition of this invention. Alternatively, when the active material layer or the solid electrolyte layer is not formed from the inorganic solid electrolyte composition of this invention, known materials can be used.

[0330] In this invention, each constituent layer (including current collectors, etc.) constituting the all-solid-state secondary battery can be a single-layer structure or a multi-layer structure.

[0331] <Positive electrode active material layer, solid electrolyte layer, negative electrode active material layer>

[0332] Regarding the types and amounts of the components contained therein, the active material layer or solid electrolyte layer formed by the inorganic solid electrolyte composition of the present invention is preferably the same as that in the solid components of the inorganic solid electrolyte composition of the present invention.

[0333] There are no particular limitations on the thickness of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer. Considering the size of a typical all-solid-state secondary battery, the thickness of each layer is preferably 10 to 1,000 μm, more preferably 20 μm or more and less than 500 μm. In the all-solid-state secondary battery of the present invention, the thickness of at least one of the positive electrode active material layer and the negative electrode active material layer is further preferably 50 μm or more and less than 500 μm.

[0334] The positive electrode active material layer and the negative electrode active material layer can each have a current collector on the side opposite to the solid electrolyte layer.

[0335] <Current Collector>

[0336] The positive and negative current collectors are preferably electron conductors.

[0337] In this invention, either the positive current collector or the negative current collector, or both of them together, are sometimes referred to simply as a current collector.

[0338] In addition to aluminum, aluminum alloys, stainless steel, nickel, and titanium, materials in which carbon, nickel, titanium, or silver (materials forming thin films) are treated on the surface of aluminum or stainless steel are preferred as the material forming the positive current collector. Among these, aluminum and aluminum alloys are more preferred.

[0339] In addition to aluminum, copper, copper alloys, stainless steel, nickel, and titanium, materials that have been treated with carbon, nickel, titanium, or silver on the surface of aluminum, copper, copper alloys, or stainless steel are preferred as materials for forming the negative current collector. More preferably, aluminum, copper, copper alloys, and stainless steel are preferred.

[0340] Current collectors are typically in the form of a membrane, but can also be made of mesh, perforated material, lath, porous material, foam, or fiber assembly.

[0341] There is no particular limitation on the thickness of the current collector, but it is preferably 1 to 500 μm. Furthermore, it is also preferable to have irregularities on the surface of the current collector through surface treatment.

[0342] <Other Structures>

[0343] In this invention, functional layers or components may be appropriately inserted or disposed between or on the outside of the layers of the negative electrode current collector, the negative electrode active material layer, the solid electrolyte layer, the positive electrode active material layer, and the positive electrode current collector.

[0344] <Shell>

[0345] The all-solid-state secondary battery of the present invention can be used as an all-solid-state secondary battery in the above-described structural state depending on the application, but in order to make it into a dry cell form, it is preferable to further enclose it in a suitable casing. The casing can be a metallic casing or a resin (plastic) casing. When using a metallic casing, for example, a casing made of aluminum alloy or stainless steel can be cited. Preferably, the metallic casing is divided into a positive electrode side casing and a negative electrode side casing, which are electrically connected to the positive electrode current collector and the negative electrode current collector, respectively. Preferably, the positive electrode side casing and the negative electrode side casing are joined together as one piece with a short-circuit prevention gasket.

[0346] The following is for reference. Figure 1 The preferred embodiments of the present invention will be described, but the present invention is not limited thereto.

[0347] Figure 1 This is a schematic cross-sectional view illustrating a preferred embodiment of the all-solid-state secondary battery (lithium-ion secondary battery) of the present invention. Viewed from the negative electrode side, the all-solid-state secondary battery 10 of this embodiment sequentially comprises a negative electrode current collector 1, a negative electrode active material layer 2, a solid electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode current collector 5. Each layer is in contact with the others and has an adjacent structure. By employing such a structure, electrons (electrons) are supplied to the negative electrode side during charging.- ), and accumulate lithium ions (Li) here. + On the other hand, during discharge, lithium ions (Li) accumulated at the negative electrode... + The electrons return to the positive side and supply electrons to the working part 6. In the illustrated example, a light bulb is used as a model in the working part 6, and the bulb is lit by discharging.

[0348] In having Figure 1 When the layered solid-state secondary battery shown is placed in a 2032-type button cell, it is sometimes referred to as a laminate for solid-state secondary batteries. A battery made by placing the laminate for solid-state secondary batteries in a 2032-type button cell is called a solid-state secondary battery.

[0349] (Positive electrode active material layer, solid electrolyte layer, negative electrode active material layer)

[0350] In the all-solid-state secondary battery 10, the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer are all formed from the inorganic solid electrolyte composition of the present invention. This all-solid-state secondary battery 10 exhibits excellent battery performance. The inorganic solid electrolyte and polymer binder contained in the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 can be of the same type or different types.

[0351] In this invention, either or both of the positive electrode active material layer and the negative electrode active material layer are simply referred to as the active material layer or the electrode active material layer. Furthermore, either or both of the positive electrode active material and the negative electrode active material are collectively referred to as the active material or the electrode active material.

[0352] The solid electrolyte layer contains an inorganic solid electrolyte having ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and the following components within the range that do not impair the effects of the present invention, and generally does not contain positive electrode active materials and / or negative electrode active materials.

[0353] The positive electrode active material layer contains an inorganic solid electrolyte having ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, a positive electrode active material, and the following components within the scope that do not impair the effects of the present invention.

[0354] The negative electrode active material layer contains an inorganic solid electrolyte having ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, a negative electrode active material, and the following components within the scope that do not impair the effects of the present invention.

[0355] In the all-solid-state secondary battery 10, the negative electrode active material layer can be a lithium metal layer. Examples of lithium metal layers include layers formed by stacking or molding lithium metal powder, lithium foil, and lithium vapor-deposited films. The thickness of the lithium metal layer is independent of the thickness of the negative electrode active material layer, and for example, can be set to 1 to 500 μm.

[0356] In this invention, either or both of the positive electrode active material layer and the negative electrode active material layer are simply referred to as the active material layer or the electrode active material layer. Furthermore, either or both of the positive electrode active material and the negative electrode active material are collectively referred to as the active material or the electrode active material.

[0357] (Current collector)

[0358] The positive current collector 5 and the negative current collector 1 are as described above.

[0359] [Manufacturing of all-solid-state rechargeable batteries]

[0360] All-solid-state secondary batteries can be manufactured using conventional methods. Specifically, all-solid-state secondary batteries can be manufactured by forming the aforementioned layers using the inorganic solid electrolyte composition of the present invention. This will be described in detail below.

[0361] The all-solid-state secondary battery of the present invention can be manufactured by performing a method (the method for manufacturing the sheet for all-solid-state secondary battery of the present invention) that includes a step of forming a coating film by appropriately coating the inorganic solid electrolyte composition of the present invention onto a substrate (e.g., a metal foil that serves as a current collector).

[0362] For example, a positive electrode active material layer is formed by coating a metal foil, which serves as the positive electrode current collector, with a dried inorganic solid electrolyte composition containing positive electrode active material as the positive electrode material (positive electrode composition), to create a positive electrode sheet for an all-solid-state secondary battery. Next, an inorganic solid electrolyte composition for forming the solid electrolyte layer is coated and dried on this positive electrode active material layer to form a solid electrolyte layer. Furthermore, an inorganic solid electrolyte composition containing negative electrode active material is coated and dried on the solid electrolyte layer to form a negative electrode active material layer. By overlapping a negative electrode current collector (metal foil) on the negative electrode active material layer, an all-solid-state secondary battery with a structure in which the solid electrolyte layer is sandwiched between the positive and negative electrode active material layers can be obtained. It can also be encapsulated in a casing to form a desired all-solid-state secondary battery.

[0363] Furthermore, in contrast to the methods for forming each layer, it is also possible to manufacture an all-solid-state secondary battery by forming a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer on a negative electrode current collector as a substrate and then overlapping a positive electrode current collector.

[0364] As another method, the following approach can be used: The positive electrode sheet for an all-solid-state secondary battery is manufactured as described above. Similarly, a negative electrode active material layer is formed by coating a dried inorganic solid electrolyte composition containing negative electrode active material onto a negative electrode current collector to create an all-solid-state secondary battery negative electrode sheet. Next, a solid electrolyte layer is formed on the active material layer of any one of these sheets, as described above. Furthermore, the positive electrode sheet for an all-solid-state secondary battery and another negative electrode sheet for an all-solid-state secondary battery are stacked on the solid electrolyte layer in such a way that the solid electrolyte layer and the active material layer are in contact. In this way, an all-solid-state secondary battery can be manufactured.

[0365] Furthermore, as another method, the following can be cited: That is, to manufacture the positive electrode sheet and the negative electrode sheet for an all-solid-state secondary battery as described above. In addition, a solid electrolyte sheet for an all-solid-state secondary battery, consisting of a solid electrolyte layer, is manufactured by coating an inorganic solid electrolyte composition onto a substrate. Moreover, the solid electrolyte layer, which has been peeled off from the substrate, is stacked in a manner where the positive electrode sheet and the negative electrode sheet for an all-solid-state secondary battery hold it in place. In this way, an all-solid-state secondary battery can be manufactured.

[0366] Furthermore, as described above, a positive electrode sheet, a negative electrode sheet, and a solid electrolyte sheet for an all-solid-state secondary battery are manufactured. Next, the positive or negative electrode active material layer and the solid electrolyte sheet are overlapped and pressurized. This transfers the solid electrolyte layer onto the positive or negative electrode sheet. Then, the solid electrolyte layer obtained by peeling off the substrate of the solid electrolyte sheet is overlapped with the negative or positive electrode sheet (while the negative or positive electrode active material layer is in contact with the solid electrolyte layer) and pressurized. In this way, an all-solid-state secondary battery can be manufactured. The pressing method and conditions in this method are not particularly limited, and the methods and conditions described in the pressing process described later can be used.

[0367] Solid electrolyte layers, for example, are formed by pressurizing an inorganic solid electrolyte composition onto a substrate or active material layer under pressure conditions described later.

[0368] In the above manufacturing method, the inorganic solid electrolyte composition of the present invention can be used for any one of the positive electrode composition, the inorganic solid electrolyte composition, and the negative electrode composition. It is preferred to use the inorganic solid electrolyte composition of the present invention for at least one of the inorganic solid electrolyte composition or the positive electrode composition and the negative electrode composition. It is also possible to use the inorganic solid electrolyte composition of the present invention for any composition.

[0369] <Formation of each layer (film formation)>

[0370] There are no particular limitations on the coating method for the inorganic solid electrolyte composition, and appropriate methods can be selected. For example, wet coating methods such as spraying, spin coating, dip coating, slot coating, strip coating, and bar coating can be cited.

[0371] At this point, the inorganic solid electrolyte composition can be dried after separate coating or after multi-layer coating. There are no particular limitations on the drying temperature. The lower limit is preferably 30°C or higher, more preferably 60°C or higher, and even more preferably 80°C or higher. The upper limit is preferably 300°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower. By heating within this temperature range, the dispersion medium can be removed to obtain a solid state (coated dry layer). Furthermore, it avoids excessively high temperatures and damage to the components of the all-solid-state secondary battery, which is therefore preferable. As a result, the all-solid-state secondary battery exhibits excellent overall performance and achieves good adhesion and good ionic conductivity even without pressure.

[0372] As described above, when the inorganic solid electrolyte composition of the present invention is coated and dried, deviations in the contact state can be suppressed and solid particles can be bonded together, and a coated and dried layer with a flat surface can be formed.

[0373] After coating with an inorganic solid electrolyte composition, the layers are stacked to form a solid-state secondary battery, or after fabrication of an all-solid-state secondary battery, each layer or the all-solid-state secondary battery is pressurized. Furthermore, pressurization is preferably performed while the layers are stacked. Examples of pressurization methods include hydraulic cylinder presses. There are no particular limitations on the pressurization pressure, but a range of 5 to 1500 MPa is generally preferred.

[0374] Furthermore, the coated inorganic solid electrolyte composition can be heated simultaneously with pressurization. There are no particular limitations on the heating temperature, which is generally in the range of 30 to 300°C. Stamping can also be performed at temperatures higher than the glass transition temperature of the inorganic solid electrolyte. Additionally, stamping can also be performed at temperatures higher than the glass transition temperature of the polymer contained in the polymer binder. However, the temperature is generally no higher than the melting point of the polymer.

[0375] Pressurization can be performed either with the solvent or dispersion medium pre-dried or with residual solvent or dispersion medium remaining.

[0376] Alternatively, the various compositions can be coated simultaneously, or the coating, drying, and stamping can be performed simultaneously and / or sequentially. They can be laminated by transfer printing after being coated onto their respective substrates.

[0377] There are no particular restrictions on the atmosphere used in film-forming methods (coating, drying, pressurization (under heating)). It can be any atmosphere, including atmospheric pressure, dry air (dew point below -20°C), or inert gases (e.g., argon, helium, nitrogen).

[0378] The stamping time can be either a short period of time (e.g., within a few hours) to apply high pressure, or a long period of time (more than one day) to apply medium pressure. In the case of solid-state secondary batteries, except for sheets for all-solid-state secondary batteries, medium pressure can be continuously applied using the constraint tools of all-solid-state secondary batteries (such as screw tightening pressure).

[0379] Compared to the pressure-bearing parts such as the surface of the sheet, the stamping pressure can be uniform or varying.

[0380] The stamping pressure can be varied according to the area or film thickness of the pressed part. Furthermore, it is also possible to apply different pressures to the same part in stages.

[0381] The stamped surface can be smooth or rough.

[0382] <Initialization>

[0383] All-solid-state secondary batteries manufactured in the manner described above are preferably initialized after manufacturing or before use. There are no particular limitations on initialization; for example, initial charging and discharging can be performed under increased stamping pressure, followed by releasing the pressure until the normal operating pressure of the all-solid-state secondary battery is reached.

[0384] Applications of all-solid-state rechargeable batteries

[0385] The all-solid-state secondary battery of this invention is applicable to a wide variety of uses. There are no particular limitations on its application; for example, when incorporated into electronic devices, it can be used in laptops, pen-and-paper computers, mobile computers, e-book readers, mobile phones, cordless phones, pagers, handheld terminals, portable fax machines, portable copiers, portable printers, stereo headphones, camcorders, LCD TVs, portable vacuum cleaners, portable CD players, mini disk drives, electric shavers, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, etc. As other civilian products, it can be used in automobiles (electric vehicles), electric vehicles, motors, lighting fixtures, toys, game consoles, load conditioners, clocks, flashlights, cameras, and medical devices (pacemakers, hearing aids, and shoulder massagers, etc.). Furthermore, it can be used in various military and aerospace applications. It can also be combined with solar cells.

[0386] Example

[0387] The present invention will now be described in further detail with reference to embodiments, but the invention is not limited thereto. In the following embodiments, unless otherwise specified, "parts" and "%" of composition refer to mass. In the present invention, "room temperature" refers to 25°C.

[0388] The following examples show the polymers used in the embodiments and comparative examples. The numbers listed in the lower right corner of each component indicate the content (mass %). In the following polymers, Me represents methyl, and the wavy lines in polymers B-11 and T-5 represent the bonding portions with the polymer chain.

[0389] [Chemical Formula 5]

[0390]

[0391] [Chemical Formula 6]

[0392]

[0393] 1. Polymer synthesis and preparation of adhesive solutions or adhesive dispersions

[0394] The above chemical formulas and the polymers shown in Table 1 were synthesized as follows.

[0395] [Preparation Example 1: Synthesis of Polymer B-1 and Preparation of Adhesive Solution B-1]

[0396] Monomer solution B-1 was prepared by adding 23.4 g of dodecyl acrylate, 12.6 g of 1H,1H,2H,2H-tridecylfluorooctyl methacrylate, and 0.36 g of polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) to a 100 mL graduated cylinder and dissolving it in 36.0 g of butyl butyrate.

[0397] 18 g of butyl butyrate was added to a 300 mL three-necked flask, and the monomer solution (B-1) was added dropwise after stirring at 80 °C for 2 hours. After the addition was completed, the temperature was raised to 90 °C and stirred for 2 hours to synthesize polymer B-1, thus obtaining solution B-1 (polymer concentration 40% by mass) of an adhesive composed of (meth)acrylic acid polymer B-1.

[0398] [Preparation Examples 2-16: Synthesis of polymers B-2-B-7, B-13, B-16-B-19, T-1, T-6, T-8 and T-9, and preparation of adhesive solutions B-2-B-7, B-13, B-16-B-19, T-1, T-6, T-8 and T-9]

[0399] In Preparation Example 1 above, polymers B-2 to B-7, B-13, B-16 to B-19, T-1, T-6, T-8, and T-9 were introduced into the compounds of each constituent component in a manner that resulted in the composition (type and content of the constituent components) shown in the above chemical formula. Otherwise, in the same manner as in Preparation Example 1 above, (meth)acrylic acid polymers or vinyl polymers B-2 to B-7, B-13, B-16 to B-19, T-1, T-6, T-8, and T-9 were synthesized, and solutions of adhesives composed of each polymer, B-2 to B-7, B-13, B-16 to B-19, T-1, T-6, T-8, and T-9, were prepared respectively.

[0400] Additionally, the macromonomer used in (meth)acrylic acid polymers B-6 and B-7 is X-22-174BX (trade name, manufactured by Shin-Etsu Silicone Co., Ltd.). Among these macromonomers, R... Y It is an alkylene or arylene group, R Z It is alkyl or aryl, and m is 25 to 35 (mass average molecular weight 1500 to 3500).

[0401] [Preparation Example 17: Synthesis of Polymer B-8 and Preparation of Adhesive Solution B-8]

[0402] 10.0 g of butyl butyrate, 1.0 g of vinylidene fluoride, 3.0 g of butyl acrylate, and 6.0 g of styrene were added to an autoclave, followed by the addition of 0.1 g of diisopropyl peroxide. The mixture was stirred at 30 °C for 24 hours. After the polymerization reaction was complete, the precipitate was filtered and dried at 100 °C for 10 hours to obtain vinyl polymer B-8.

[0403] The vinyl polymer B-8 was dissolved in butyl butyrate to prepare a solution B-8 of the adhesive composed of polymer B-8 (polymer concentration 40% by mass).

[0404] [Preparation Example 18: Synthesis of Polymer B-9 and Preparation of Adhesive Solution B-9]

[0405] Monomer solution B-9 was prepared by adding 4.32 g of dodecyl acrylate, 10.1 g of 1H,1H,2H,2H-tridecylfluorooctyl methacrylate, 18.00 g of styrene, 3.6 g of acrylonitrile, and 0.36 g of polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako PureChemical Corporation) to a 100 mL graduated cylinder and dissolving it in 36.0 g of butyl butyrate.

[0406] 18 g of butyl butyrate was added to a 300 mL three-necked flask, and the monomer solution (B-9) was added dropwise after stirring at 80 °C for 2 hours. After the addition was complete, the temperature was raised to 90 °C and stirred for 2 hours to synthesize polymer B-9, thus obtaining a solution B-9 (polymer concentration 40% by mass) of an adhesive composed of (meth)acrylic acid polymer B-9.

[0407] [Preparation Example 19: Synthesis of Polymer B-15 and Preparation of Adhesive Solution B-15]

[0408] In Preparation Example 18 above, compounds of each constituent component were introduced in such a way that (meth)acrylic polymer B-15 became the composition (type and content of constituent components) shown in the above chemical formula. Otherwise, (meth)acrylic polymer B-15 was synthesized in the same manner as in Preparation Example 18 above, and a solution B-15 of adhesive composed of each polymer was prepared.

[0409] [Preparation Example 20: Synthesis of Polymer B-10 and Preparation of Adhesive Solution B-10]

[0410] Monomer solution B-10 was prepared by adding 10.8 g of butyl acrylate, 21.6 g of styrene, 3.6 g of silicone macromonomer X-22-174BX (trade name), and 0.36 g of polymerization initiator V-601 (trade name, manufactured by FUJIFILM Wako Pure Chemical Corporation) to a 100 mL graduated cylinder and dissolving them in 36.0 g of butyl butyrate.

[0411] 18 g of butyl butyrate was added to a 300 mL three-necked flask, and the monomer solution (B-10) was added dropwise after stirring at 80 °C for 2 hours. After the addition was complete, the temperature was raised to 90 °C and stirred for 2 hours to synthesize polymer B-10, thus obtaining solution B-10 (polymer concentration 40% by mass) of an adhesive composed of vinyl polymer B-10.

[0412] [Preparation Example 21: Synthesis of Polymer B-11 and Preparation of Adhesive Solution B-11]

[0413] Monomer solution B-11 was prepared by adding 136.6 g of dodecyl acrylate, 73.4 g of 1H,1H,2H,2H-tridecylfluorooctyl acrylate, 3.85 g of 3-mercaptopropionic acid, and 4.20 g of polymerization initiator V-601 (trade name) to a 500 mL graduated cylinder and dissolving them in 57.0 g of butyl butyrate. 71.3 g of butyl butyrate was added to a 1000 mL three-necked flask, and after stirring at 80 °C for 2 hours, monomer solution B-11 was added dropwise, followed by stirring at 80 °C for another 2 hours. Then, 0.42 g of polymerization initiator V-601 was added, the temperature was raised to 95 °C, and the mixture was stirred for another 2 hours. The obtained solution was further added with 6.2 g of glycidyl methacrylate, 0.2 g of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxo radical, and 2.6 g of tetrabutylammonium bromide, and stirred at 100 °C for 3 hours. The resulting reaction solution was then redeprecipitated with methanol to synthesize the macromonomer MM-11 (SP value 17.6, number average molecular weight 5,000).

[0414] Next, in Preparation Example 1, compounds of each constituent component were introduced in such a way that the vinyl polymer B-11 became the composition (type and content of constituent components) shown in the above chemical formula. Otherwise, the vinyl polymer B-11 was synthesized in the same manner as in Preparation Example 1, and a solution B-11 of adhesive composed of vinyl polymer B-11 was prepared.

[0415] [Preparation Examples 22-24: Synthesis of polymers B-12, B-14 and T-7 and preparation of adhesive solutions B-12, B-14 and T-7]

[0416] (Meth)acrylic polymers B-12, B-14 and T-7 were synthesized using compounds of each constituent component derived in a manner that resulted in the composition (type and content of constituent components) shown in paragraphs

[0101] and

[0102] of Japanese Patent Application Publication No. 2011-054439, respectively.

[0417] The synthesized (meth)acrylic acid polymers B-12, B-14 and T-7 were dissolved in butyl butyrate to prepare adhesive solutions B-12, B-14 and T-7 (polymer concentration 40% by mass) composed of polymers B-12, B-14 or T-7 respectively.

[0418] [Preparation Examples 25 and 26: Synthesis of Polymers T-5 and T-10 and Preparation of Adhesive Dispersions T-5 and T-10]

[0419] In Preparation Example 21 above, compounds containing each constituent component were introduced in such a manner that (meth)acrylic acid polymers T-5 and T-10 were the composition (types and amounts of constituent components) shown in the above chemical formulas. Otherwise, (meth)acrylic acid polymers T-5 and T-10 were synthesized in the same manner as in Preparation Example 21 above. The macromonomer MM-2 synthesized from polymer T-5 had an SP value of 18.9 and a number-average molecular weight of 5,000. The macromonomer MM-3 synthesized from polymer T-10 had an SP value of 15.9 and a number-average molecular weight of 5,000.

[0420] The synthesized polymers T-5 and T-10 were dispersed in butyl butyrate to prepare dispersions T-5 and T-10 of the adhesive composed of polymers T-5 and T-10, respectively (both with a polymer concentration of 40% by mass and an average particle size of 5 μm).

[0421] [Preparation Examples 27-29: Preparation of Adhesive Solutions T-2-T-4]

[0422] Fluoropolymers T-2 (trade name: KF polymer, manufactured by KUREHA CORPORATION), T-3 (trade name: Tecnoflon (registered trademark) NH, manufactured by Solvay SA), and T-4 (trade name: Tecnoflon (registered trademark) TN, manufactured by Solvay S.A.) were dissolved in butyl butyrate to prepare adhesive solutions T-2 to T-4 (polymer concentration 40% by mass) composed of each polymer.

[0423] The surface energy, SP value, and elastic modulus of each synthesized polymer are shown in Table 1. The SP value of the polymer was determined using the method described above.

[0424] The surface energy was measured as follows.

[0425] -Fabrication of Polymer Membranes-

[0426] On a silicon wafer (3×N type, manufactured by AS ONE Corporation), 100 μL of the adhesive solution or adhesive dispersion prepared above was coated by a spin coater under the following coating conditions, and then vacuum dried at 100°C for 2 hours to produce polymer films of each adhesive.

[0427] (Coating conditions)

[0428] Concentration of adhesive solution: 40% by mass

[0429] Spin coater speed: 2000 rpm

[0430] Spin coater rotation time: 5 seconds

[0431] - Surface Energy Calculation -

[0432] The contact angles of diiodomethane and water relative to the polymer film fabricated on a silicon wafer as described above were determined using the θ / 2 method in the droplet method. Here, after the droplet contacts the surface of the polymer film and falls for 200 milliseconds, the angle between the sample surface (the surface of the polymer film) and the droplet (the angle located inside the droplet) is taken as the contact angle θ.

[0433] Using the measured contact angles θ, the values ​​calculated by the Owens method described below are taken as the surface energy.

[0434] <Owens method>

[0435] 1+cosθH2O=2√γSd(√γH2Od / γH2O,V)+2√γSh(√γH2Oh / γH2O,V) 1+cosθCH2I2=2√γSd(√γCH2I2d / γCH2I2,V)+2√γSh(√γCH2I2h / γCH2I2,V)

[0436] The symbols for the above formulas are as follows.

[0437] θH₂O: Contact angle of water (°)

[0438] θCH2I2: Contact angle of diiodomethane (°)

[0439] γSd: The dispersive force component of the polymer's surface energy (mN / m)

[0440] γH₂Od: The dispersive force component of the surface energy of water (mN / m)

[0441] γH₂O,V: Total surface energy of water (mN / m)

[0442] γSh: Hydrogen bonding component of the polymer's surface energy (mN / m)

[0443] γH2O: Hydrogen-bonded component of water surface energy (mN / m)

[0444] γCH2I2d: Dispersive force component of the surface energy of diiodomethane (mN / m)

[0445] γCH2I2,V: Total surface energy of diiodomethane (mN / m)

[0446] γCH2I2h: Hydrogen bonding component of the surface energy of diiodomethane (mN / m)

[0447] The elastic modulus was measured as follows.

[0448] -Production of the experimental film-

[0449] The adhesive solution or dispersion prepared above was placed in a glass petri dish and dried at 120°C for 6 hours to obtain a dried membrane with a thickness of 80 μm. The obtained dried membrane was cut into strips 10 mm wide and 40 mm long to prepare test pieces.

[0450] -Determination of Elastic Modulus-

[0451] Each prepared test piece was placed on a force gauge (manufactured by IMADA) with the clamp spacing at 30 mm. Under these conditions, the test piece was stretched at a speed of 10 mm / min, and the displacement and stress were measured. The tensile modulus of elasticity was calculated from the initial slope.

[0452] [Table 1]

[0453]

[0454] For the raw material compounds used in the synthesis of the above polymers, the SP values ​​of the constituent components are shown below.

[0455] Dodecyl acrylate: 18.8 MPa 1 / 2

[0456] 1H,1H,2H,2H-Tetrafluorooctyl methacrylate: 13.7 MPa 1 / 2

[0457] 1H,1H,2H,2H-Nonfluorohexyl methacrylate: 14.5 MPa 1 / 2

[0458] 1H,1H-heptafluorobutyl methacrylate: 14.8 MPa 1 / 2

[0459] Butyl acrylate: 19.5 MPa 1 / 2

[0460] Octyl acrylate: 19.0 MPa 1 / 2

[0461] X-22-174BX: 17.7MPa 1 / 2

[0462] Vinylidene fluoride: 13.1 MPa 1 / 2

[0463] Styrene: 19.3 MPa 1 / 2

[0464] Acrylonitrile: 25.3 MPa 1 / 2

[0465] 2-Ethylhexyl acrylate: 18.7 MPa 1 / 2

[0466] Methacrylic acid (CH2)2(CF2) 13 (CF3): 12.1 MPa 1 / 2

[0467] Methacrylic acid (CH2)2(CF2)7(CF3): 13.1 MPa 1 / 2

[0468] 1H,1H,2H,2H-Pentafluorobutyl methacrylate: 15.9 MPa 1 / 2

[0469] Hexafluoropropylene: 10.1 MPa 1 / 2

[0470] Tetrafluoroethylene: 10.1 MPa 1 / 2

[0471] Acrylic acid: 20.5 MPa 1 / 2

[0472] 2-Hydroxyethyl acrylate: 25.9 MPa 1 / 2

[0473] 2. Synthesis of sulfide-based inorganic solid electrolytes [Synthesis Example A]

[0474] The sulfide-based inorganic solid electrolyte was synthesized with reference to non-patent literature, T. Ohtomo, A. Hayashi, M. Tatsumisago, Y. Tsuchida, S. Hama, K. Kawamoto, Journal of Power Sources, 233, (2013), pp231-235 and A. Hayashi, S. Hama, H. Morimoto, M. Tatsumisago, T. Minami, Chem. Lett., (2001), pp872-873.

[0475] Specifically, 2.42 g of lithium sulfide (Li₂S, manufactured by Aldrich, Inc., purity > 99.98%) and 3.90 g of phosphorus pentasulfide (P₂S₅, manufactured by Aldrich, Inc., purity > 99%) were weighed out in a glove box under an argon atmosphere (dew point -70°C) and placed into an agate mortar. The mixture was then mixed for 5 minutes using an agate pestle. The molar ratio of Li₂S to P₂S₅ was set as Li₂S:P₂S₅ = 75:25.

[0476] Next, 66g of 5mm diameter zirconia beads were added to a 45mL zirconia container (manufactured by Fritsch Co., Ltd.), along with the total amount of the aforementioned mixture of lithium sulfide and phosphorus pentasulfide. The container was then completely sealed under argon atmosphere. The container was placed in a planetary ball mill P-7 (trade name, manufactured by Fritsch Co., Ltd.) and mechanically ground at 25°C and 510 rpm for 20 hours, yielding 6.20g of a yellow powder sulfide-based inorganic solid electrolyte (Li-PS glass, hereinafter, sometimes labeled LPS). The Li-PS glass had a particle size of 15μm.

[0477] [Example 1]

[0478] The compositions shown in Table 2 were prepared as follows.

[0479] <Preparation of inorganic solid electrolyte compositions K-1, K-2 and KC-1 to KC-10>

[0480] 60 g of zirconia beads with a diameter of 5 mm were added to a 45 mL container (manufactured by Fritsch Co., Ltd.), along with 8.4 g of LPS synthesized in Synthesis Example A above, 0.6 g (solid mass) of the binder solution or binder dispersion shown in Tables 2-1 and 2-3, and 11 g of butyl butyrate as the dispersion medium. The container was then placed in a planetary ball mill P-7 (trade name) manufactured by Fritsch Co., Ltd. Mixing was performed at 25°C and 150 rpm for 10 minutes to prepare inorganic solid electrolyte compositions (slurries) K-1, K-2, and KC-1 to KC-10, respectively.

[0481] <Preparation of cathode compositions PK-1 to PK-21>

[0482] 60g of 5mm diameter zirconia beads were added to a 45mL zirconia container (manufactured by Fritsch Co., Ltd.), along with 8g of LPS synthesized in Synthesis Example A above and 13g of butyl butyrate as a dispersion medium (total). The container was placed in a Fritsch Co., Ltd. planetary ball mill P-7 (trade name) and stirred at 25°C and 200rpm for 30 minutes. Then, 27.5g of NMC (manufactured by Sigma-Aldrich Co. LLC) as the positive electrode active material, 1.0g of acetylene black (AB) as a conductive additive, and 0.5g of the binder solution shown in Table 2-1 (mass of solid components) were added to the container. The container was placed in a planetary ball mill P-7 and mixed for another 30 minutes at 25°C and 200rpm, respectively, to prepare positive electrode compositions (slurries) PK-1 to PK-21.

[0483] <Preparation of negative electrode compositions NK-1 to NK-21 and NKC-1 to NKC-10>

[0484] 60 g of zirconia beads with a diameter of 5 mm were added to a 45 mL zirconia container (manufactured by Fritsch Co., Ltd.), along with 16.6 g of LPS synthesized in Synthesis Example A above, 0.66 g (solid mass) of the binder solution or binder dispersion shown in Tables 2-2 and 2-3, and 33.3 g (total) of dispersion medium. The container was placed in a Fritsch Co., Ltd. planetary ball mill P-7 (trade name) and mixed for 60 minutes at 25°C and a speed of 300 rpm. Then, 14.6g of silicon (Si, manufactured by Aldrich, CO.LTD.) as the negative electrode active material and 1.3g of VGCF (SHOWA DENKOK.K.) as the conductive additive were added. Similarly, the container was placed in a planetary ball mill P-7 and mixed for 10 minutes at a temperature of 25°C and a speed of 100 rpm to prepare negative electrode compositions (slurries) NK-1 to NK-21 and NKC-1 to NKC-10, respectively.

[0485] Tables 2-1 to 2-3 (collectively referred to as Table 2) show the SP values ​​of the polymers and dispersion media forming the polymeric binders. Furthermore, for each composition, the difference (absolute value) between the SP value of the polymer forming the polymeric binder and the SP value of the dispersion media is calculated and displayed. The units for the SP values ​​and the difference in SP values ​​are MPa. 1 / 2 However, this information is omitted from Table 2.

[0486] In Table 2, the composition content is the content (mass%) relative to the total mass of the composition, and the solid component content is the content (mass%) relative to 100% mass of the solid component of the composition. Units are omitted in the table.

[0487] [Table 2-1]

[0488]

[0489] [Table 2-2]

[0490]

[0491] [Table 2-3]

[0492]

[0493] <Abbreviation for table>

[0494] LPS: LPS synthesized in Synthesis Example A

[0495] NMC: LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2

[0496] Si: Silicon

[0497] AB: Acetylene Black

[0498] VGCF: Carbon nanotubes (made by SHOWA DENKO KK)

[0499] <Fabrication of solid electrolyte sheets 101, 102 and C11 to C20 for all-solid-state secondary batteries>

[0500] Using a baking applicator (trade name: SA-201, manufactured by TESTER SANGYO CO,. LTD.), the inorganic solid electrolyte compositions shown in the "Solid Electrolyte Composition No." column of Tables 3-1 and 3-3 obtained above were coated onto aluminum foil with a thickness of 20 μm. The coatings were then heated at 80°C for 2 hours and dried (to remove the dispersion medium). Next, using a hot press, the dried inorganic solid electrolyte compositions were heated and pressurized for 10 seconds at 120°C and 40 MPa to produce solid electrolyte sheets (labeled as solid electrolyte sheets in Table 3) 101, 102, and c11–c20 for all-solid-state secondary batteries. The film thickness of the solid electrolyte layer was 50 μm.

[0501] <Fabrication of positive electrode sheets 103-123 for all-solid-state secondary batteries>

[0502] Using a baking applicator (trade name: SA-201), each of the positive electrode compositions shown in the "Electrode Composition No." column of Table 3-1 obtained above was coated onto an aluminum foil with a thickness of 20 μm. The coating was heated at 80°C for 1 hour, and then further heated at 110°C for 1 hour, and dried (to remove the dispersion medium). Then, using a hot press, the dried positive electrode compositions were pressurized at 25°C (10 MPa, 1 min) to produce positive electrode sheets (labeled as positive electrode sheets in Table 3) for all-solid-state secondary batteries with a positive electrode active material layer with a film thickness of 80 μm. 103 to 123.

[0503] <Fabrication of negative electrode sheets 124-144 and C21-C30 for all-solid-state secondary batteries>

[0504] Using a baking applicator (trade name: SA-201), the negative electrode compositions shown in the "Electrode Composition No." column of Tables 3-2 and 3-3 obtained above were coated onto copper foil with a thickness of 20 μm. The coatings were heated at 80°C for 1 hour, and then further heated at 110°C for 1 hour, followed by drying (removal of the dispersion medium). Then, using a hot press, the dried negative electrode compositions were pressurized at 25°C (10 MPa, 1 minute) to produce negative electrode sheets (labeled as negative electrode sheets in Table 3) 124–144 and c21–c30 for all-solid-state secondary batteries, each having a negative electrode active material layer with a film thickness of 70 μm.

[0505] The various compositions and sheets manufactured were evaluated as follows, and the results are shown in Tables 3-1 to 3-3 (collectively referred to as Tables 3).

[0506] <Evaluation 1: Dispersion>

[0507] The viscosity of each composition prepared as described above was measured, and the dispersibility was evaluated based on which of the following evaluation criteria it was included in.

[0508] In this experiment, the lower the viscosity, the better the dispersibility, and an evaluation standard of "D" or above is considered acceptable.

[0509] -Viscosity Measurement Methods-

[0510] Using an E-type viscometer (TV-35 type, manufactured by Toki Sangyo Co., Ltd.) and a standard conical rotor (1°34'×R24), 1.1 mL of the sample (composition) was added to a sample cup adjusted to the specified measurement temperature and placed in the main body. After maintaining the temperature for 5 minutes until it became constant, the measurement range was set to "U". The value obtained after 1 minute of rotation at a shear rate of 10 / s (rotation speed of 2.5 rpm) was taken as the viscosity.

[0511] -Evaluation Criteria-

[0512] A: Less than 300 cP

[0513] B: 300 cP or more but less than 500 cP

[0514] C: 500 cP or more but less than 800 cP

[0515] D: Above 800 cP and below 1500 cP

[0516] E: 1500cP or higher

[0517] <Evaluation 2: Interface Resistance>

[0518] (1) Preparation of test specimens for measuring ionic conductivity

[0519] The obtained solid electrolyte sheet or electrode sheet (the positive electrode sheet and the negative electrode sheet for all-solid-state secondary batteries) is cut into a circular plate shape with a diameter of 14.5 mm, and the solid electrolyte sheet or electrode sheet is placed into Figure 2 the 2032-type button cell case 11 shown. Specifically, an aluminum foil cut into a circular plate shape with a diameter of 15 mm ( Figure 2 not shown in ) is brought into contact with the solid electrolyte layer or the electrode active material layer, and spacers and washers (both not shown in Figure 2 are assembled, and it can be placed into the stainless steel 2032-type button cell case 11. By fixing the 2032-type button cell case 11, a test body for measuring ionic conductivity fastened with a force of 8 Newtons (N) was fabricated.

[0520] (2) Measurement of the ionic conductivity of the test body for measuring ionic conductivity

[0521] For each of the above-prepared test bodies for measuring ionic conductivity, the ionic conductivity at 0 °C was measured, and the interfacial resistance under low-temperature conditions was evaluated. Specifically, for each test body for measuring ionic conductivity, in a thermostat at 0 °C, using a 1255B FREQUENCY RESPONSE ANALYZER (trade name, manufactured by SOLARTRON), the alternating current impedance was measured up to a voltage amplitude of 5 mV and a frequency of 1 MHz to 1 Hz. Thereby, the resistance in the layer thickness direction of the sample for measuring ionic conductivity was obtained, and the ionic conductivity under low-temperature conditions was calculated by the following formula (1).

[0522] Formula (1): Ionic conductivity σ (mS / cm) =

[0523] 1000 × sample layer thickness (cm) / [resistance (Ω) × sample area (cm 2 )]

[0524] In formula (1), the sample layer thickness is a value measured before the solid electrolyte sheet or the electrode active material layer is placed into the 2*032-type button cell case 11, and is obtained by subtracting the thickness of the current collector (the total layer thickness of the solid electrolyte layer and the electrode active material layer). The sample area is the area of a circular plate-shaped sheet with a diameter of 14.5 mm.

[0525] It is determined whether the obtained ionic conductivity σ is included in any of the following evaluation criteria.

[0526] In the ionic conductivity σ in this experiment, those above the evaluation criterion "D" are considered qualified.

[0527] - Evaluation criteria -

[0528] For the case of the solid electrolyte sheet

[0529] A: 1.6 ≤ σ

[0530] B: 1.4 ≤ σ < 1.6

[0531] C: 1.2 ≤ σ < 1.4

[0532] D: 1.0 ≤ σ < 1.2

[0533] E: σ < 1.0 (Electrode plate case)

[0534] A: 0.8≤σ

[0535] B: 0.7 ≤ σ < 0.8

[0536] C: 0.6 ≤ σ < 0.7

[0537] D: 0.5 ≤ σ < 0.6

[0538] E: σ < 0.5

[0539] <Evaluation 3: SE Degradation Suppression>

[0540] For the solid electrolyte sheet and electrode sheet, the sheet material was placed in air (25°C, 50% relative humidity) for 1 hour before and after exposure to air. For a group of all-solid-state secondary batteries manufactured in the same manner as described later in [Manufacturing of All-Solid-State Secondary Batteries], the ionic conductivity was measured. The rate of decrease (%) in ionic conductivity of the all-solid-state secondary battery with the sheet material before placement and the all-solid-state secondary battery with the sheet material after placement was calculated, and the degradation inhibition effect of the solid electrolyte (SE) was evaluated by which of the following evaluation criteria it was included in. Regarding the measurement of ionic conductivity, except that the measurement temperature was changed to 25°C, the measurement was performed in the same manner as in "(2) Measurement of ionic conductivity of the test body for ionic conductivity measurement" in <Evaluation 2: Interface Resistance> above.

[0541] In this experiment, the smaller the decrease rate (%) in ionic conductivity, the better it can suppress the deterioration of inorganic solid electrolytes caused by moisture. Evaluation standard "D" or above is considered qualified.

[0542] Reduction rate of ionic conductivity (%) = [(ionic conductivity of the all-solid-state secondary battery before placement - ionic conductivity of the all-solid-state secondary battery after placement) / ionic conductivity before placement] × 100

[0543] -Evaluation Criteria-

[0544] A: More than 90%

[0545] B: 80% or more but less than 90%

[0546] C: 70% or more but less than 80%

[0547] D: 60% or more but less than 70%

[0548] E: Less than 60%

[0549] <Evaluation 4: Fit>

[0550] As a reference test, the adhesion between the current collector and the active material layer in the positive electrode sheet and negative electrode sheet of all-solid-state secondary batteries was evaluated.

[0551] Specifically, test pieces measuring 20mm in length and 20mm in width are cut from the positive and negative electrode sheets of each all-solid-state secondary battery. For each test piece, 11 slits are made parallel to one side at 1mm intervals using a cutter to reach the substrate (aluminum foil or copper foil). Then, 11 more slits are made perpendicular to these slits at 1mm intervals to reach the substrate. This creates 100 squares on the test piece.

[0552] A 15mm x 18mm transparent tape (registered trademark) was applied to the surface of the active material layer to cover all 100 squares. The surface of the transparent tape (registered trademark) was rubbed with an eraser, pressed against the active material layer, and allowed to adhere. After 2 minutes, the tape (registered trademark) was held at one end and pulled vertically upwards relative to the active material layer to peel off. After peeling off the tape (registered trademark), the surface of the active material layer was visually observed, and the number of squares that did not peel off completely from the current collector was counted. The adhesion of the active material layer to the current collector was evaluated based on which of the following evaluation criteria it met.

[0553] In this test, the more squares that are not peeled off from the current collector, the stronger the seal with the current collector. A rating of "D" or above is considered acceptable.

[0554] -Evaluation Criteria-

[0555] A: 80 or more

[0556] B: 60 or more grids but less than 80 grids

[0557] C: 40 or more grids but less than 60 grids

[0558] D: 30 or more grids but less than 40 grids

[0559] E: Less than 30 grids

[0560] [Table 3-1]

[0561]

[0562] [Table 3-2]

[0563]

[0564] [Table 3-3]

[0565]

[0566] [Manufacturing of all-solid-state rechargeable batteries]

[0567] Using solid electrolyte sheets and electrode sheets prepared as follows, a device with... Figure 1 The layered structure shown is an all-solid-state secondary battery.

[0568] <Fabrication of positive electrode sheets 103-123 for all-solid-state secondary batteries with solid electrolyte layers>

[0569] By having the solid electrolyte layer in contact with the positive electrode active material layer, the solid electrolyte sheet c11 for all-solid-state secondary batteries shown in the "Electrode Active Material Layer (Sheet No.)" column of Table 4-1 was laminated onto the positive electrode active material layer of each all-solid-state secondary battery positive electrode sheet prepared above. After being pressurized at 25°C and 50MPa and then transferred (laminated) using a press, it was pressurized at 25°C and 600MPa, thereby producing all-solid-state secondary battery positive electrode sheets 103 to 123 with a solid electrolyte layer of 30μm thickness (positive electrode active material layer of 60μm thickness).

[0570] <Fabrication of negative electrode sheets 124-144 and C21-C30 for all-solid-state secondary batteries with solid electrolyte layers>

[0571] By having the solid electrolyte layer in contact with the negative electrode active material layer, the solid electrolyte sheets for all-solid-state secondary batteries shown in the "Solid Electrolyte Layer (Sheet No.)" column of Table 4-2 were laminated onto the negative electrode active material layer of each all-solid-state secondary battery negative electrode sheet. After being pressurized at 50 MPa at 25°C and transferred (laminated) using a press, they were pressurized at 600 MPa at 25°C to produce all-solid-state secondary battery negative electrode sheets (50 μm thick negative electrode active material layer) 124 to 144 and c21 to c30, respectively, with a solid electrolyte layer of 30 μm thickness.

[0572] <Manufacturing of All-Solid-State Secondary Batteries>

[0573] The following manufactured with Figure 1 The layered structure shown is No. 101, an all-solid-state secondary battery.

[0574] (Fabrication of negative electrode sheet No. c21 for all-solid-state secondary batteries with solid electrolyte layer)

[0575] First, a negative electrode sheet No. c21 with a solid electrolyte layer for manufacturing all-solid-state secondary batteries No. 101 was produced.

[0576] By having the solid electrolyte layer in contact with the negative electrode active material layer, the solid electrolyte sheet No. 101 for all-solid-state secondary batteries shown in the "Solid Electrolyte Layer (Sheet No.)" column of Table 4-1 was laminated onto the negative electrode active material layer of the all-solid-state secondary battery negative electrode sheet No. c21 shown above. After pressing at 50 MPa at 25°C and performing transfer (lamination) using a press, the sheet was pressed at 600 MPa at 25°C. Thus, a solid electrolyte layer with a film thickness of 30 μm (the film thickness of the negative electrode active material layer is 50 μm) for all-solid-state secondary battery negative electrode sheet No. c21 was fabricated.

[0577] (Manufacturing of all-solid-state secondary batteries)

[0578] The negative electrode sheet No. c21 (aluminum foil containing solid electrolyte No. 101 that has been peeled off) for an all-solid-state secondary battery with the solid electrolyte obtained above is cut into circular plates with a diameter of 14.5 mm, and as follows: Figure 2 The assembly shown includes spacers and gaskets (in...) Figure 2 In a stainless steel 2032-type button cell battery case 11 (not shown), a positive electrode sheet (positive active material layer) cut to a diameter of 14.0 mm from the positive electrode sheet for all-solid-state secondary batteries (prepared as described below) is stacked on a solid electrolyte layer. A stainless steel foil (positive current collector) is then further stacked on top to form an all-solid-state secondary battery laminate 12 (a laminate composed of copper foil, negative active material layer, solid electrolyte layer, positive active material layer, aluminum foil, and stainless steel foil). The 2032-type button cell battery case 11 is then pressed together, thereby manufacturing a... Figure 2 The all-solid-state secondary battery shown is No. 101.

[0579] In the manufacture of the aforementioned all-solid-state secondary battery No. 101, the solid electrolyte sheet No. 102 for all-solid-state secondary batteries was used instead of the solid electrolyte sheet No. 101 for all-solid-state secondary batteries. Otherwise, the all-solid-state secondary battery No. 102 was manufactured in the same manner as the manufacture of the all-solid-state secondary battery No. 101.

[0580] The following is an example of manufacturing an all-solid-state secondary battery, No. 103.

[0581] The positive electrode sheet No. 103 (aluminum foil with the solid electrolyte layer already peeled off) for an all-solid-state secondary battery with the aforementioned solid electrolyte layer is cut into circular plates with a diameter of 14.5 mm, and as shown in the figure. Figure 2 The assembly shown includes spacers and gaskets (in...) Figure 2 In a stainless steel 2032-type button cell battery case 11 (not shown), lithium foil cut into disc shapes with a diameter of 15 mm is stacked on a solid electrolyte layer. Stainless steel foil is then stacked on top to form a laminate 12 for an all-solid-state secondary battery (a laminate composed of aluminum foil, positive electrode active material layer, solid electrolyte layer, lithium foil, and stainless steel foil). The 2032-type button cell battery case 11 is then pressed together, thereby manufacturing a... Figure 2 The all-solid-state secondary battery 13 shown is No. 103.

[0582] All-solid-state secondary batteries manufactured in this way have Figure 1 The layer structure shown (where the lithium foil corresponds to the negative electrode active material layer 2 and the negative electrode current collector 1).

[0583] In the manufacture of the aforementioned all-solid-state secondary battery No. 103, the all-solid-state secondary battery positive electrode sheet with a solid electrolyte layer shown in the "Electrode Active Material Layer (Sheet No.)" column of Table 4-1 was used instead of the all-solid-state secondary battery positive electrode sheet No. 103 with a solid electrolyte layer. Otherwise, all-solid-state secondary batteries No. 104 to 123 were manufactured in the same manner as the all-solid-state secondary battery No. 103.

[0584] Next, the following was made with Figure 1 The layered structure shown is No. 124, an all-solid-state secondary battery.

[0585] The negative electrode sheet No. 124 (aluminum foil with the solid electrolyte sheet already peeled off) of each all-solid-state secondary battery with the solid electrolyte obtained above is cut into circular plates with a diameter of 14.5 mm, and as shown in the figure. Figure 2 The assembly shown includes spacers and gaskets (in...) Figure 2 In a stainless steel 2032-type button cell battery case 11 (not shown), a positive electrode sheet (positive active material layer) cut to a diameter of 14.0 mm from the positive electrode sheet for all-solid-state secondary batteries (prepared as described below) is stacked on a solid electrolyte layer. A stainless steel foil (positive current collector) is then further stacked on top to form an all-solid-state secondary battery laminate 12 (a laminate composed of copper foil, negative active material layer, solid electrolyte layer, positive active material layer, aluminum foil, and stainless steel foil). The 2032-type button cell battery case 11 is then pressed together, thereby manufacturing a... Figure 2 The all-solid-state secondary battery shown is No. 124.

[0586] The following are examples of positive electrode sheets for all-solid-state secondary batteries No. 101 and 124, which are used to manufacture all-solid-state secondary batteries.

[0587] (Preparation of the positive electrode composition)

[0588] 180 zirconia beads with a diameter of 5 mm were added to a 45 mL zirconium oxide container (manufactured by Fritsch Co., Ltd.), along with 2.7 g of LPS synthesized in Synthesis Example A above, 0.3 g of KYNAR FLEX 2500-20 (trade name, PVdF-HFP: polyvinylidene fluoride hexafluoropropylene copolymer, manufactured by ARKEMA), and 22 g of butyl butyrate. The container was placed in a Fritsch Co., Ltd. planetary ball mill P-7 (trade name) and stirred at 25°C and 300 rpm for 60 minutes. Then, 7.0 g of LiNi was added as the positive electrode active material. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (NMC) was assembled in the same manner in a planetary ball mill P-7 and mixed for 5 minutes at 25°C and 100 rpm to prepare positive electrode compositions.

[0589] (Fabrication of positive electrode sheets for all-solid-state secondary batteries)

[0590] The obtained positive electrode composition was coated onto a 20 μm thick aluminum foil (positive electrode current collector) using a baking applicator (trade name: SA-201, manufactured by TESTER SANGYO CO,. LTD.). The positive electrode composition was heated at 100°C for 2 hours and then dried (to remove the dispersion medium). Then, using a hot press, the dried positive electrode composition was pressurized at 25°C (10 MPa, 1 min) to produce a positive electrode sheet for all-solid-state secondary batteries with a positive electrode active material layer of 80 μm thickness.

[0591] In the manufacture of the aforementioned all-solid-state secondary battery No. 124, the all-solid-state secondary battery negative electrode sheet with a solid electrolyte layer shown in the "Electrode Active Material Layer (Sheet No.)" column of Table 4-2 was used instead of the all-solid-state secondary battery negative electrode sheet No. 124 with a solid electrolyte layer. Otherwise, all-solid-state secondary batteries No. 125 to 144 and c101 to c110 were manufactured in the same manner as the manufacture of all-solid-state secondary battery No. 124.

[0592] The following evaluations were performed on each of the manufactured all-solid-state secondary batteries, and the results are shown in Tables 4-1 and 4-2 (collectively referred to as Table 4).

[0593] <Evaluation 5: Cyclic Characteristics>

[0594] For each of the manufactured all-solid-state secondary batteries, the discharge capacity retention rate was measured using the TOSCAT-3000 charge-discharge evaluation device (trade name, manufactured by TOYOSYSTEM Co., Ltd.).

[0595] Specifically, each all-solid-state secondary battery was charged at 25°C until the current density reached 0.1 mA / cm². 2 And continue discharging until the battery voltage reaches 3.6V. Then, discharge until the current density reaches 0.1mA / cm². 2 The battery voltage was maintained at 2.5V. One charge and one discharge cycle was considered as one charge-discharge cycle, and this process was repeated for three cycles under the same conditions to initialize the battery. Then, the above charge-discharge cycle was repeated, and the discharge capacity of each all-solid-state secondary battery was measured using a charge-discharge evaluation device: TOSCAT-3000 (trade name) at each charge-discharge cycle.

[0596] When the initial discharge capacity (initial discharge capacity) of the first charge-discharge cycle after initialization is set to 100%, the number of charge-discharge cycles required to achieve a discharge capacity retention rate (discharge capacity relative to the initial discharge capacity) of 80% is evaluated using which of the following criteria? In this test, a higher number of cycles indicates better battery performance (cycle characteristics), maintaining initial battery performance even after repeated charge-discharge cycles (even with long-term use). In this test, a rating of "D" or higher is considered acceptable.

[0597] Furthermore, the initial discharge capacity of the all-solid-state secondary batteries of the present invention all show values ​​sufficient for functioning as all-solid-state secondary batteries.

[0598] -Evaluation Criteria-

[0599] A: More than 500 cycles

[0600] B: 300 cycles or more but less than 500 cycles

[0601] C: 150 cycles or more but less than 300 cycles

[0602] D: 80 cycles or more but less than 150 cycles

[0603] E: Less than 80 cycles

[0604] <Evaluation 6: Ionic conductivity>

[0605] The ionic conductivity of each manufactured all-solid-state secondary cell was measured. Specifically, for each all-solid-state secondary cell, the AC impedance was measured in a constant temperature bath at 30°C using a 1255B FREQUENCY RESPONSE ANALYZER (trade name, manufactured by SOLARTRON) up to a voltage amplitude of 5mV and a frequency of 1MHz to 1Hz. From this, the resistance in the thickness direction of the sample used for ionic conductivity measurement was determined, and the ionic conductivity was calculated using the following formula (1).

[0606] Formula (1): Ionic conductivity σ (mS / cm) =

[0607] 1000 × thickness of the sample layer (cm) / [resistance (Ω) × sample area (cm 2 )]

[0608] In Formula (1), the thickness of the sample layer is the value obtained by measuring before placing the laminate 12 into the button cell case 11 of type 2032 and subtracting the thickness of the current collector (the total thickness of the solid electrolyte layer and the electrode active material layer). The sample area is the area of a disc-shaped sheet with a diameter of 14.5 mm.

[0609] Determine whether the obtained ionic conductivity σ falls within any of the following evaluation criteria.

[0610] In the ionic conductivity σ in this experiment, those above the evaluation criterion "D" are considered qualified.

[0611] - Evaluation Criteria -

[0612] A: 1.0 ≤ σ

[0613] B: 0.9 ≤ σ < 1.0 ​​​​​​​​​​​​​​​​​​​​​​​​​​

[0623] In contrast, the inorganic solid electrolyte compositions containing the polymer binder specified in this invention, as shown in K-1, K-2, PK-1 to PK-21, and NK-1 to NK-21 of the present invention, possess dispersibility, the effect of inhibiting the degradation of inorganic solid electrolytes, and ionic conductivity (interface resistance) at low temperatures. Furthermore, by using electrode compositions PK-1 to PK-21 and NK-1 to NK-21 to form the active material layer of an all-solid-state secondary battery, a strong adhesion between the obtained electrode sheet and the current collector can be achieved. Moreover, it is known that all-solid-state secondary batteries with constituent layers formed using these inorganic solid electrolyte compositions can achieve high ionic conductivity and excellent cycle characteristics.

[0624] Furthermore, the aforementioned degradation test of the inorganic solid electrolyte caused by moisture was conducted using sheets for all-solid-state secondary batteries, which are most susceptible to contact with moisture in actual manufacturing processes. If the degradation inhibition effect of the inorganic solid electrolyte is demonstrated in the all-solid-state secondary battery sheet, the same effect can be expected in the constituent layers of an all-solid-state secondary battery where an inorganic solid electrolyte-containing composition coexists with the polymer binder specified in this invention.

[0625] Symbol Explanation

[0626] 1-Negative current collector, 2-Negative active material layer, 3-Solid electrolyte layer, 4-Positive active material layer, 5-Positive current collector, 6-Working part, 10-All-solid-state secondary battery, 11-Type 2032 button cell battery case, 12-Laminated body for all-solid-state secondary battery, 13-Button type all-solid-state secondary battery.

Claims

1. A composition containing an inorganic solid electrolyte, comprising: an inorganic solid electrolyte having conductive ions of metals belonging to Group 1 or Group 2 of the periodic table, a polymer binder, and a dispersion medium. in, The polymer adhesive comprises materials with a surface energy of less than 20 mN / m and an SP value of 14–21.5 MPa. 1 / 2 The polymer, and the polymer binder is dissolved in the dispersion medium. The polymer has constituent components on its main chain or side chains represented by the following formula (LF) or formula (LS). [Chemical Formula 1] In formula (LF) or formula (LS), R 1 ~R 3 Represents a hydrogen atom or a substituent. L represents a single bond or a linking group. R F This indicates a substituent containing both carbon and fluorine atoms. R S This indicates a substituent containing silicon atoms. The inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte.

2. The inorganic solid electrolyte composition according to claim 1, wherein, The polymer has an elastic modulus of 1 MPa or higher.

3. The inorganic solid electrolyte composition according to claim 1 or 2, wherein, The polymer is a grafted polymer.

4. The inorganic solid electrolyte composition according to claim 1 or 2, wherein, The main chain of the polymer is a block polymer.

5. The inorganic solid electrolyte composition according to claim 1 or 2, wherein, The SP value of the dispersion medium is 14–24 MPa. 1 / 2 .

6. The inorganic solid electrolyte composition according to claim 1 or 2, wherein it contains an active substance.

7. The inorganic solid electrolyte composition according to claim 1 or 2, wherein it contains a conductive additive.

8. A sheet for an all-solid-state secondary battery, having a layer composed of an inorganic solid electrolyte composition as described in any one of claims 1 to 7.

9. An all-solid-state secondary battery, comprising sequentially 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, and the negative electrode active material layer is a layer composed of an inorganic solid electrolyte composition as described in any one of claims 1 to 7.

10. A method for manufacturing a sheet for an all-solid-state secondary battery, wherein the inorganic solid electrolyte composition according to any one of claims 1 to 7 is used to form a film.

11. A method for manufacturing an all-solid-state secondary battery, wherein the all-solid-state secondary battery is manufactured by the manufacturing method described in claim 10.

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