CN113228343A

CN113228343A - Solid electrolyte composition, solid electrolyte-containing sheet, all-solid-state secondary battery, and method for producing solid electrolyte-containing sheet and all-solid-state secondary battery

Info

Publication number: CN113228343A
Application number: CN201980085639.5A
Authority: CN
Inventors: 三村智则
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2018-12-27
Filing date: 2019-12-24
Publication date: 2021-08-06
Also published as: KR20210089759A; JP7096366B2; WO2020138122A1; JPWO2020138122A1

Abstract

The present invention provides a solid electrolyte composition, a solid electrolyte-containing sheet and an all-solid-state secondary battery each having a layer formed from the solid electrolyte composition, and a method for manufacturing the solid electrolyte-containing sheet and the all-solid-state secondary battery, the solid electrolyte composition including: an inorganic solid electrolyte having conductivity of an ion of a metal belonging to group 1 or group 2 of the periodic table; a binder comprising a step-polymerization polymer having a constituent component of a specific structure; and a dispersion medium.

Description

Solid electrolyte composition, solid electrolyte-containing sheet, all-solid-state secondary battery, and method for producing solid electrolyte-containing sheet and all-solid-state secondary battery

Technical Field

The present invention relates to a solid electrolyte composition, a solid electrolyte-containing sheet, an all-solid-state secondary battery, and a method for manufacturing the solid electrolyte-containing sheet and the all-solid-state secondary battery.

Background

A lithium ion secondary battery is a storage battery that has a negative electrode, a positive electrode, and an electrolyte interposed between the negative electrode and the positive electrode and is capable of being charged and discharged by reciprocating lithium ions between the two electrodes. In a lithium ion secondary battery, an organic electrolytic solution has been used as an electrolyte. However, the organic electrolytic solution is liable to cause liquid leakage, and also short-circuiting and ignition may occur inside the battery due to overcharge or overdischarge, and thus further improvement in safety and reliability is required.

Under such circumstances, attention is paid to an all-solid secondary battery using an inorganic solid electrolyte instead of an organic electrolytic solution. The negative electrode, the electrolyte, and the positive electrode of the all-solid-state secondary battery are all made of a solid, and the safety and reliability of the battery using the organic electrolyte can be greatly improved.

In such an all-solid-state secondary battery, a material containing an inorganic solid electrolyte, an active material, a binder (binder), and the like as materials forming constituent layers such as a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer has been proposed.

For example, patent document 1 describes a solid electrolyte composition containing an inorganic solid electrolyte having conductivity of ions of a metal belonging to group 1 or group 2 of the periodic table and a polymer binder composed of a polymer having a hard segment and a soft segment.

Prior art documents

Patent document

Patent document 1: japanese laid-open patent publication (JP 2015-088480)

Disclosure of Invention

Technical problem to be solved by the invention

The constituent layers of all-solid secondary batteries are generally formed of solid particles such as inorganic solid electrolytes and active materials, and since interfacial contact between solid particles is originally limited, a reduction in interfacial resistance is also limited (a reduction in ion conductivity). On the other hand, if the adhesion between the solid particles is weak, the constituent layer formed on the surface of the current collector is easily peeled off from the current collector, and a contact failure between the solid particles, particularly caused by shrinkage and expansion of the active material layer, occurs in the constituent layer accompanying charge and discharge (release and absorption of lithium ions) of the all-solid secondary battery, resulting in an increase in resistance and a decrease in battery performance. Although studies have been made on the structure of the polymer constituting the binder in order to improve the adhesion between the solid particles, further improvement is required for suppressing contact failure due to shrinkage and expansion of the active material layer.

The present invention addresses the problem of providing a solid electrolyte composition that exhibits excellent dispersibility and that, when used as a material for forming constituent layers of an all-solid secondary battery, can achieve excellent battery performance by firmly binding solid particles while suppressing an increase in the interfacial resistance between the solid particles in the obtained all-solid secondary battery. Further, an object of the present invention is to provide a solid electrolyte-containing sheet having a layer composed of the solid electrolyte composition, and an all-solid-state secondary battery. Another object of the present invention is to provide a solid electrolyte-containing sheet using the solid electrolyte composition and a method for manufacturing an all-solid-state secondary battery.

Means for solving the technical problem

As a result of extensive studies, the present inventors have found that the use of a binder containing a step-polymerization polymer, which is a polymer having at least two components selected from the group consisting of a peroxy atom, a sulfur atom and a nitrogen atom-containing group via a specific linking group, as a solid electrolyte composition, enables the polymers to interact with each other appropriately between the components of each other, and improves the dispersibility of the solid electrolyte composition. Further, it has been found that by using the solid electrolyte composition as a material for forming a constituent layer of an all-solid-state secondary battery, a constituent layer in which solid particles are strongly bonded while suppressing the interface resistance between the solid particles can be formed, and an all-solid-state secondary battery exhibiting excellent battery performance can be manufactured. The present invention has been completed by further conducting a study based on these findings.

That is, the above problems are solved by the following means.

<1>

A solid electrolyte composition comprising: an inorganic solid electrolyte having conductivity of an ion of a metal belonging to group 1 or group 2 of the periodic table; a binder containing a step-polymerization polymer having a constituent component represented by the following formula (H-1); and a dispersion medium.

[ chemical formula 1]

In the formula, L¹¹Represents an alkylene group having 1 to 12 carbon atoms, an arylene group having 6 to 18 carbon atoms, an alkenylene group having 2 to 12 carbon atoms, a 2-valent heterocyclic group having 4 to 18 carbon atoms, an oxygen atom, a carbonyl group, or-N (R)^N1) -or an imine linking group or a combination thereof. X¹¹And X¹²Represents an oxygen atom, a sulfur atom or-N (R)^N1) -. Wherein, X¹¹And X¹²Are different from each other. R^N1Represents a hydrogen atom, an alkylsilyl group, an aryl group having 6 to 18 carbon atoms or an alkyl group having 1 to 12 carbon atoms.

＜2＞

The solid electrolyte composition according to < 1 > wherein,

the stepwise polymerization type polymer has a partial structure represented by the following formula (H-2).

[ chemical formula 2]

In the formula, L²¹The meaning of (1) and the above-mentioned L¹¹Have the same meaning. R^N2Has the meaning of R^N1Have the same meaning. The bond portion for introducing the partial structure into the stepwise polymerization-based polymer is represented.

＜3＞

The solid electrolyte composition according to < 1 > or < 2 >, wherein,

the stepwise polymerization type polymer has a partial structure represented by the following formula (H-3).

[ chemical formula 3]

L³¹An alkylene group having 1 to 12 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, an imine linking group, or a combination thereof, and a group having a molecular weight of 400 or less, wherein the group represents a bonding portion for introducing the above partial structure into the stepwise polymerization polymer.

＜4＞

The solid electrolyte composition according to any one of < 1 > to < 3 >, wherein,

the stepwise polymerization type polymer is a polymer represented by the following formula.

[ chemical formula 4]

In the formula, L¹To representMolecular chains having a molecular weight of 14 or more and 200,000 or less.

X¹、X²And L²Are as defined above for X¹¹X is mentioned above¹²And the above-mentioned L¹¹Have the same meaning.

X³And X⁴All represent-NH-or an oxygen atom, L³Represents a hydrocarbon group.

X⁵And X⁶All represent-NH-or an oxygen atom, L⁴Represents a polycarbonate chain, a polyester chain or a polyalkylene oxide chain.

X⁷And X⁸All represent-NH-or an oxygen atom, L⁵Represents a hydrocarbon polymer chain.

s1 to s5 represent the contents (% by mass) of the respective constituent components, and the total is 100% by mass.

＜5＞

The solid electrolyte composition according to any one of < 1 > to < 4 >, wherein,

the urea value of the stepwise polymerization polymer is more than 0 and not more than 0.5 mmol/g.

＜6＞

The solid electrolyte composition according to any one of < 1 > to < 5 >, wherein,

the binder is particles having an average particle diameter of 5nm to 10 μm.

＜7＞

The solid electrolyte composition according to any one of < 1 > to < 6 >, wherein,

the content of the binder is 0.001-10 mass% of the total solid content of the solid electrolyte composition.

＜8＞

The solid electrolyte composition according to any one of < 1 > to < 7 >, wherein,

the step-polymerization-type polymer has at least one functional group selected from the following functional group (I).

< group of functional groups (I) >)

Carboxyl group, sulfonic group, keto group, phosphoric group

＜9＞

The solid electrolyte composition according to any one of < 1 > to < 8 >, wherein,

the mass average molecular weight of the stepwise polymerization polymer is 10000 to 90000.

＜10＞

The solid electrolyte composition according to any one of < 1 > to < 9 > containing a conduction aid.

＜11＞

The solid electrolyte composition according to any of < 1 > to < 10 > comprising an active substance.

＜12＞

The solid electrolyte composition according to < 11 > wherein,

the active material is a negative electrode active material containing silicon atoms.

＜13＞

The solid electrolyte composition according to any one of < 1 > to < 12 >, wherein,

the inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte represented by the following formula (1).

Formula (1): l is_a1M_bP_cS_dA_e

Wherein L represents an element selected from Li, Na and K. 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. a 1-e 1 represent the composition ratio of each element, and a1: b1: c1: d1: e1 satisfies 1-12: 0-5: 1: 2-12: 0-10.

＜14＞

The solid electrolyte composition according to any one of < 1 > to < 13 >, wherein,

the dispersion medium is at least one of a ketone compound solvent, an ester compound solvent, an aromatic compound solvent and an aliphatic compound solvent.

＜15＞

A solid electrolyte-containing sheet having a layer composed of the solid electrolyte composition described in any one of < 1 > to < 14 >.

＜16＞

An all-solid-state secondary battery comprising a positive electrode active material layer, a negative electrode active material layer and a solid electrolyte layer in this order,

at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is composed of the solid electrolyte composition described in any one of < 1 > to < 14 >.

＜17＞

A method for producing a solid electrolyte-containing sheet, comprising a step of applying the solid electrolyte composition described in any one of < 1 > to < 14 >.

＜18＞

A method for manufacturing an all-solid-state secondary battery, comprising a step of applying the solid electrolyte composition described in any one of < 1 > to < 14 >.

Effects of the invention

The solid electrolyte composition of the present invention is excellent in dispersion stability. The solid electrolyte composition of the present invention can realize a solid electrolyte-containing sheet having excellent adhesion between solid particles and the like in constituent layers and excellent ion conductivity, and an all-solid-state secondary battery having excellent battery performance. The solid electrolyte-containing sheet of the present invention is excellent in adhesion between solid particles and the like in constituent layers thereof and ion conductivity. The all-solid-state secondary battery of the present invention is excellent in battery performance. The method for producing a solid electrolyte-containing sheet and the methods for producing all-solid-state secondary batteries according to the present invention can provide the solid electrolyte-containing sheet and all-solid-state secondary batteries.

Drawings

Fig. 1 is a schematic longitudinal sectional view of an all-solid secondary battery according to a preferred embodiment of the present invention.

Fig. 2 is a vertical sectional view schematically showing the sample for ion conductivity measurement or an all-solid-state secondary battery (button cell) produced in the example.

Detailed Description

In the description of the present invention, the numerical range represented by "to" means a range in which the numerical values before and after "to" are included as the lower limit value and the upper limit value.

In the present specification, when simply referred to as "acrylic" or "(meth) acrylic", it means acrylic acid and/or methacrylic acid.

In the present specification, the expression "compound" (for example, when the compound is referred to as being attached to the end of the specification) means that the compound itself contains a salt thereof or an ion thereof. Further, the term "derivative" includes derivatives in which a part such as a substituent is introduced by changing the way within a range in which a desired effect is achieved.

In the present specification, the term "substituted or unsubstituted substituent, linking group or the like (hereinafter referred to as" substituent or the like ") is not specifically described, and means that the group may have an appropriate substituent. Therefore, in the present specification, even when a YYY group is simply referred to, the YYY group includes an unsubstituted form and a substituted form. This also applies to compounds which are not explicitly described as substituted or unsubstituted. Preferred substituents include the following substituent T.

In the present specification, the presence of a plurality of substituents or the like represented by specific symbols or the presence of a plurality of substituents or the like defined simultaneously or selectively means that the substituents or the like may be the same or different from each other. Further, unless otherwise specified, when a plurality of substituents and the like are adjacent to each other, these may be connected to each other or fused to form a ring.

[ solid electrolyte composition ]

The solid electrolyte composition of the present invention comprises: an inorganic solid electrolyte having conductivity of an ion of a metal belonging to group 1 or group 2 of the periodic table; a binder containing a step-polymerization polymer having a constituent component represented by the following formula (H-1); and a dispersion medium.

[ chemical formula 5]

In the formula, L¹¹Represents a carbon atomAlkylene group having a sub-number of 1 to 12, arylene group having 6 to 18 carbon atoms, alkenylene group having 2 to 12 carbon atoms, oxygen atom, -N (R)^N1) -a silane linking group or an imine linking group or a combination of these groups, atoms or linking groups. X¹¹And X¹²Represents an oxygen atom, a sulfur atom or-N (R)^N1) -. Wherein, X¹¹And X¹²Are different from each other. R^N1Represents a hydrogen atom, an alkylsilyl group or an alkyl group having 1 to 12 carbon atoms.

The present invention can achieve both high and stable dispersibility of a solid electrolyte composition and strong adhesion between solid particles and the like at a high level while suppressing an increase in interface impedance. Therefore, it is considered that the constituent layer composed of the solid electrolyte composition of the present invention exhibits high strength, and the contact state between the solid particles (the amount of the build-up of the ion conduction path) and the adhesion force between the solid particles are improved in a well-balanced manner, and the solid particles are bonded with strong adhesion while the ion conduction path is built up, and the interface resistance between the solid particles is reduced. Each sheet or all-solid-state secondary battery provided with a constituent layer exhibiting such excellent characteristics exhibits high ionic conductivity while suppressing an increase in resistance, and can maintain such excellent battery performance even when charging and discharging are repeated.

The reason is not clear, but is presumed as follows.

By introducing a highly polar component into the polymer constituting the binder, the polymers strongly interact with each other, and the polymers are agglomerated with each other, whereby the mechanical strength of the polymers can be improved. However, if the interaction between the polymers is too strong, the polymers agglomerate and precipitate. That is, the mechanical strength of the polymer is in a trade-off relationship with the dispersibility of a slurry containing the polymer.

It is considered that the solid electrolyte composition of the present invention has a constituent component represented by the above formula (H-1) by a polymer constituting a binder, the polymers being present in X¹¹And X¹²One side of the polymer particles strongly interacts with the other side of the polymer particles, and the interaction on the other side is intentionally weakened, whereby a desired cohesive force can be imparted to the polymer(mechanical strength) and adhesion to solid particles, and further, the dispersibility thereof can be improved in the case of producing a slurry.

When the constituent layer is formed from the solid electrolyte composition of the present invention, the solid particles to which the polymer constituting the binder adheres are dispersed with high uniformity in the constituent layer of the solid electrolyte-containing sheet of the present invention and the all-solid-state secondary battery of the present invention, and therefore, the ion conductivity of the sheet, the adhesiveness of the solid particles and the like in the constituent layer, and the battery performance of the all-solid-state secondary battery are considered to be excellent.

In the present invention, the excellent dispersibility of the solid electrolyte composition means a state in which solid particles are highly and stably dispersed in a dispersion medium, and means, for example, a dispersibility of an evaluation level "4" or more in a "dispersibility test" in examples described later.

In the solid electrolyte composition of the present invention, the binder is preferably dispersed as particles (in a solid state) in the dispersion medium, and more preferably the inorganic solid electrolyte and the binder are in a dispersed state (suspension) in which the binder is dispersed in a solid state in the dispersion medium (the solid electrolyte composition is a slurry). When the binder is a layer constituting or a dried layer applied with a solid electrolyte composition described later, the solid particles such as an inorganic solid electrolyte may be bonded to each other and the adjacent layer (for example, a current collector) may be bonded to the solid particles, and in the above-described dispersed state of the solid electrolyte composition, the solid particles may not be bonded to each other.

The solid electrolyte composition of the present invention further comprises the following means: the composition of this embodiment contains, as a dispersion medium, an active material, a conductive assistant, and the like in addition to the inorganic solid electrolyte (the composition is referred to as an "electrode composition").

The solid electrolyte composition of the present invention is a nonaqueous composition. In the present invention, the nonaqueous composition includes a form not containing water and a form having a water content (also referred to as a water content) of 200ppm or less. The water content in the nonaqueous composition is preferably 150ppm or less, more preferably 100ppm or less, and still more preferably 50ppm or less. The water content indicates the amount of water contained in the solid electrolyte composition (mass ratio of water in the solid electrolyte composition). The water content can be determined by filtering the solid electrolyte composition using a 0.45 μm membrane filter and by karl fischer titration.

The components contained in the solid electrolyte composition of the present invention and components that can be contained therein will be described below.

< inorganic solid electrolyte >

In the present invention, the inorganic solid electrolyte refers to an inorganic solid electrolyte, and the solid electrolyte refers to a solid electrolyte capable of moving ions inside thereof. From the viewpoint of not containing an organic substance as a main ion conductive material, it is clearly distinguished from an organic solid electrolyte (a polymer electrolyte represented by polyethylene oxide (PEO) or the like, an organic electrolyte salt represented by lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) or the like). Further, since the inorganic solid electrolyte is a solid in a stable state, it is not usually dissociated or dissociated into cations and anions. At this point, the inorganic electrolyte salt (LiPF) dissociated from the cations and anions or dissociated in the electrolyte or polymer₆、LiBF₄LiFSI, LiCl, etc.) are clearly distinguished. The inorganic solid electrolyte is not particularly limited as long as it has ion conductivity of a metal belonging to group 1 or group 2 of the periodic table, and generally does not have electron conductivity.

In the present invention, the inorganic solid electrolyte has ion conductivity of a metal belonging to group 1 or group 2 of the periodic table. The inorganic solid electrolyte can be used by appropriately selecting a solid electrolyte material suitable for use in such a product. Typical examples of the inorganic solid electrolyte include (i) a sulfide-based inorganic solid electrolyte and (ii) an oxide-based inorganic solid electrolyte, and the sulfide-based inorganic solid electrolyte is preferable from the viewpoint of high ion conductivity and ease of interface bonding between particles.

When the all-solid-state secondary battery of the present invention is an all-solid-state lithium ion secondary battery, the inorganic solid electrolyte preferably has ion conductivity of lithium ions.

(i) Sulfide-based inorganic solid electrolyte

The sulfide-based inorganic solid electrolyte preferably contains a sulfur atom, has ion conductivity of a metal belonging to group 1 or group 2 of the periodic table, and has electronic insulation properties. The sulfide-based inorganic solid electrolyte preferably contains at least Li, S, and P as elements, has lithium ion conductivity, and may contain elements other than Li, S, and P according to the purpose or circumstances.

As the sulfide-based inorganic solid electrolyte, for example, a lithium ion-conductive sulfide-based inorganic solid electrolyte satisfying the composition represented by the following formula (1) can be exemplified.

Formula (1): l is_a1M_b1P_c1S_d1A_e1

In the formula, L represents an element selected from Li, Na and K, and Li is preferable. 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. a 1-e 1 represent the composition ratio of each element, and a1: b1: c1: d1: e1 satisfies 1-12: 0-5: 1: 2-12: 0-10. a1 is preferably 1 to 9, more preferably 1.5 to 7.5. b1 is preferably 0 to 3, more preferably 0 to 1. d1 is preferably 2.5 to 10, more preferably 3.0 to 8.5. e1 is preferably 0 to 5, more preferably 0 to 3.

As described below, the composition ratio of each element can be controlled by adjusting the compounding ratio of the raw material compound in producing the sulfide-based inorganic solid electrolyte.

The sulfide-based inorganic solid electrolyte may be amorphous (glass), may be crystallized (glass-ceramic), or may be partially crystallized. For example, a Li-P-S glass containing Li, P, and S or a Li-P-S glass ceramic containing Li, P, and S can be used.

The sulfide-based inorganic solid electrolyte can be prepared by reacting lithium sulfide (Li)₂S), phosphorus sulfides (e.g., phosphorus pentasulfide (P)₂S₅) Phosphorus monomer, sulfur monomer, sodium sulfide, hydrogen sulfide, lithium halide (e.g., LiI, LiBr, LiCl), and sulfide of the element represented by the above-mentioned M (e.g., SiS)₂、SnS、GeS₂) At least two or more ofThe reaction of the raw materials.

Li-P-S glass and Li-P-S glass ceramic₂S and P₂S₅In the ratio of Li₂S:P₂S₅The molar ratio of (a) to (b) is preferably 60:40 to 90:10, and more preferably 68:32 to 78: 22. By mixing Li₂S and P₂S₅When the ratio (b) is in this range, the lithium ion conductivity can be improved. Specifically, the lithium ion conductivity can be preferably set to 1 × 10^-4S/cm or more, more preferably 1X 10^-3And more than S/cm. The upper limit is not particularly limited, and is actually 1X 10^-1S/cm or less.

Specific examples of the sulfide-based inorganic solid electrolyte include the following combinations of raw materials. For example, Li may be mentioned₂S-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、Li₂S-P₂S₅-Al₂S₃、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、Li₁₀GeP₂S₁₂And the like. The mixing ratio of the raw materials is not limited. As a method for synthesizing a sulfide-based inorganic solid electrolyte material using such a raw material composition, for example, an amorphization method can be cited. Examples of the amorphization method include a mechanical polishing method, a solution method, and a melt quenching method. The treatment at normal temperature can be performed, and the manufacturing process can be simplified.

(ii) Oxide-based inorganic solid electrolyte

The oxide-based inorganic solid electrolyte is preferably a compound containing an oxygen atom, having ion conductivity of a metal belonging to group 1 or group 2 of the periodic table, and having electronic insulation properties.

As for the oxide-based inorganic solid electrolyte, 1 × 10 is preferable as the ion conductivity^-6S/cm or more, more preferably 5X 10^-6S/cm or more, particularly preferably 1X 10^-5And more than S/cm. The upper limit is not particularly limited, and is actually 1X 10^-1S/cm or less.

Specific examples of the compound include Li_xaLa_yaTiO₃〔xa＝0.3～0.7、ya＝0.3～0.7〕(LLT)、Li_xbLa_ybZr_zbM^bb _mbO_nb(M^bbIs at least one element of Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In and Sn, xb is more than or equal to 5 and less than or equal to 10, yb is more than or equal to 1 and less than or equal to 4, zb is more than or equal to 1 and less than or equal to 4, mb is more than or equal to 0 and less than or equal to 2, Nb is more than or equal to 5 and less than or equal to 20. ) Li_xcB_ycM^cc _zcO_nc(M^ccIs at least one element of 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)_zdSi_adP_mdO_nd(wherein, 1 is more than or equal to xd is less than or equal to 3,0 is more than or equal to yd is less than or equal to 1,0 is more than or equal to zd is less than or equal to 2,0 is more than or equal to ad is less than or equal to 1, 1 is more than or equal to md is less than or equal to 7, and 3 is more than or equal to nd is less than or equal to 13), Li_(3-2xe)M^ee _xeD^eeO (xe represents a number of 0 to 0.1, M)^eeRepresents a 2-valent metal atom. D^eeRepresents a halogen atom or a combination of two or more halogen atoms. ) Li_xfSi_yfO_zf(1≤xf≤5、0＜yf≤3、1≤zf≤10)、Li_xgS_ygO_zg(1≤xg≤3、0＜yg≤2、1≤zg≤10)、Li₃BO₃-Li₂SO₄、Li₂O-B₂O₃-P₂O₅、Li₂O-SiO₂、Li₆BaLa₂Ta₂O₁₂、Li₃PO_(4-3/2w)N_w(w satisfies w < 1), and Li having a LISICON (lithium super ionic conductor) type crystal structure_3.5Zn_0.25GeO₄La having perovskite crystal structure_0.55Li_0.35TiO₃LiTi having a NASICON (national super ionic conductor) type crystal structure₂P₃O₁₂、Li_1+xh+yh(Al，Ga)_xh(Ti，Ge)_2-xhSi_yhP_3-yhO₁₂(wherein 0. ltoreq. xh. ltoreq.1, 0. ltoreq. yh. ltoreq.1) and Li having a garnet crystal structure₇La₃Zr₂O₁₂(LLZ) and the like. Also, a phosphorus compound containing Li, P, and O is preferable. For example, lithium phosphate (Li)₃PO₄) LiPON or LiPOD in which a part of oxygen atoms in lithium phosphate is substituted with nitrogen atoms¹(D¹At least one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, Au, etc.), etc. And, LiA can also be preferably used¹ON(A¹At least one selected from Si, B, Ge, Al, C, Ga, etc.), etc.

(iii) Halide-based inorganic solid electrolyte

The halide-based inorganic solid electrolyte is preferably a compound containing a halogen atom, having ion conductivity of a metal belonging to group 1 or group 2 of the periodic table, and having electronic insulation properties.

The halide-based inorganic solid electrolyte is not particularly limited, and examples thereof include Li described in LiCl, LiBr, LiI, ADVANCED MATERIALS, 2018,30,1803075₃YBr₆、Li₃YCl₆And (c) a compound such as a quaternary ammonium compound. Among them, Li is preferable₃YBr₆、Li₃YCl₆。

(iv) Hydride inorganic solid electrolyte

The hydride-based inorganic solid electrolyte is preferably a compound containing a hydrogen atom, having ion conductivity of a metal belonging to group 1 or group 2 of the periodic table, and having electronic insulation properties.

The hydride-based inorganic solid electrolyte is not particularly limited, and examples thereof include LiBH₄、Li₄(BH₄)₃I、3LiBH₄-LiCl, etc.

The inorganic solid electrolyte is preferably a particle. In this case, the average particle diameter (volume average particle diameter) of the inorganic solid electrolyte is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.1 μm or more. The upper limit is preferably 100 μm or less, and more preferably 50 μm or less. The average particle diameter of the inorganic solid electrolyte was measured by the following procedure. In a 20ml sample bottle, the inorganic solid electrolyte particles were diluted with water (heptane in the case of a water-unstable substance) to prepare a1 mass% dispersion. The diluted dispersion sample was irradiated with ultrasonic waves at 1kHz for 10 minutes and then immediately used in the test. Using this dispersion sample, data collection was performed 50 times using a laser diffraction/scattering particle size distribution measuring apparatus LA-920 (trade name, manufactured by HORIBA, ltd.) and a quartz cell for measurement at a temperature of 25 ℃, thereby obtaining a volume average particle diameter. Other detailed conditions and the like are as required in reference to JIS Z8828: 2013 "particle size analysis-dynamic light scattering method". 5 samples were prepared for each grade and the average was used.

The inorganic solid electrolyte may be used alone or in combination of two or more.

The content of the inorganic solid electrolyte in the solid electrolyte composition is not particularly limited, and is preferably 50% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more of the solid components 100% by mass from the viewpoints of dispersibility, reduction in interface resistance, and adhesiveness. From the same viewpoint, the upper limit is preferably 99.99% by mass or less, more preferably 99.95% by mass or less, and particularly preferably 99.9% by mass or less. However, when the solid electrolyte composition contains an active material described later, the content of the inorganic solid electrolyte in the solid electrolyte composition is defined as the total content of the inorganic solid electrolyte and the active material.

In the present invention, the solid component (solid component) is a component that does not volatilize or evaporate and disappear when the solid electrolyte composition is subjected to a drying treatment at 150 ℃ for 6 hours under a pressure of 1mmHg and in a nitrogen atmosphere. Typically, it means a component other than the dispersion medium described later.

< adhesive >

The solid electrolyte composition of the present invention contains a binder that binds solid particles.

The binder is composed of a stepwise polymerization polymer described later, and is soluble in a dispersion medium, and is preferably insoluble or poorly soluble in (particles of) the dispersion medium, particularly from the viewpoint of ion conductivity.

In the present invention, the term "insoluble or poorly soluble in a dispersion medium" means that even when a binder is added to a dispersion medium at 30 ℃ (the amount used is 10 times the mass of the binder) and left to stand for 24 hours, the amount of the binder dissolved in the dispersion medium is 30 mass% or less, preferably 20 mass% or less, and more preferably 10 mass% or less. The amount of the binder dissolved in the dispersion medium after 24 hours had elapsed was defined as the ratio of the mass of the binder added to the dispersion medium.

The binder may be present in the solid electrolyte composition, for example, dissolved in a dispersion medium, or may be present in a solid form (as the insoluble or poorly soluble particles) in the dispersion medium (the binder present in a solid form is referred to as a particulate binder). In the present invention, the binder is preferably a particulate binder in the solid electrolyte composition, from the viewpoint of battery resistance and cycle characteristics. In one preferred embodiment, the particulate binder is maintained in a particulate state even in a constituent layer (coating and drying layer) such as the solid electrolyte layer and the electrode active material layer.

When the binder is a particulate binder, the shape thereof is not particularly limited, and may be flat, amorphous, or the like, and is preferably spherical or granular. The average particle diameter of the particulate binder is not particularly limited, but is preferably 5nm or more and 10 μm or less. This improves the dispersibility of the solid electrolyte composition, the adhesion between solid particles, and the like, and the ion conductivity. From the viewpoint of further improving dispersibility, adhesiveness, and ion conductivity, the average particle diameter is preferably 10nm or more and 5 μm or less, more preferably 15nm or more and 1 μm or less, and still more preferably 20nm or more and 0.5 μm or less. The average particle diameter of the binder can be measured in the same manner as in the case of the inorganic solid electrolyte.

The average particle diameter of the particulate binder in the constituent layers of the all-solid secondary battery can be measured, for example, as follows: after the battery was disassembled and the constituent layer containing the particulate binder was peeled off, the constituent layer was measured, and the measured value of the average particle diameter of the particles other than the particulate binder which had been measured in advance was removed.

For example, the average particle diameter of the particulate binder can be adjusted by the type of the dispersion medium used in preparing the binder dispersion, the content of the constituent component in the polymer constituting the binder, and the like.

From the viewpoint of dispersibility and compatibility with the adhesion between the inorganic solid electrolyte particles, the active material, the conductive assistant and other solid particles and ion conductivity, the content of the particulate binder in the solid electrolyte composition is preferably 0.001 mass% or more, more preferably 0.05 mass% or more, further preferably 0.1 mass% or more, and particularly preferably 0.2 mass% or more, in 100 mass% of the solid content. The upper limit is preferably 20 mass% or less, more preferably 10 mass% or less, and further preferably 5 mass% or less, from the viewpoint of battery capacity.

In the solid electrolyte composition of the present 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 [ (mass of the inorganic solid electrolyte + mass of the active material)/(mass of the binder) ] is preferably in the range of 1,000 to 1. The ratio is more preferably 1000 to 2, and still more preferably 500 to 10.

The polymer constituting the binder is a stepwise polymerization type polymer having a constituent component represented by the following formula (H-1).

[ chemical formula 6]

X¹¹、X¹²And L¹¹The details of which will be described later.

(step-by-step polymerization type Polymer)

In the present invention, the "step-polymerization-type polymer" refers to a polymer in which a polymer chain obtained by step-polymerization is contained as a segment in a main chain or a side chain (preferably a main chain). The stepwise polymerization type polymer may be a copolymer containing two or more kinds of polymer chains obtained by stepwise polymerization, or may be a copolymer containing segments other than the polymer chains obtained by stepwise polymerization.

The kind of the stepwise polymerization is not particularly limited, and examples of the stepwise polymerization polymer include polyesters, polyamides, polyimides, polyurethanes, polyureas, and polycarbonates, and from the viewpoint of dispersibility, battery performance, and the like, polyesters, polyamides, polyurethanes, polyureas, and the like are preferable.

The stepwise polymerization type polymer used in the present invention has a constituent component represented by the following formula (H-1). The stepwise polymerization type polymer may have a constituent represented by the following formula (H-1) in any of the main chain and the side chain, and preferably has a constituent represented by the following formula (H-1) in the main chain.

In the present invention, the main chain of the polymer refers to all molecular chains constituting the polymer, which can be regarded as branched chains or side chains (pendant) with respect to the main chain. Typically, the longest chain among the molecular chains constituting the polymer becomes the main chain, although depending on the mass average molecular weight of the molecular chain regarded as a branch or a side chain. However, the functional group at the end of the polymer is not contained in the main chain.

The side chains of the polymer are molecular chains other than the main chain, and include short molecular chains and long molecular chains.

With respect to the stepwise polymerization type polymer, a general constituent component constituting the polymer will be described, and a constituent component represented by the formula (H-1) will be described next.

The stepwise polymerization type polymer used in the present invention is preferably a polymer having a main chain in which two or more species (preferably 2 to 4 species, more preferably 2 or 3 species) are combined with a constituent represented by the formula (H-1) and a constituent represented by any one of the formulae (I-1) to (I-4) (constituent derived from a monomer) described later, or a main chain in which a carboxylic dianhydride represented by the formula (I-5) and a compound represented by the formula (I-6) are stepwise polymerized (a polymer having a main chain in which a constituent derived from a carboxylic dianhydride (monomer) represented by the formula (I-5) and a constituent derived from a compound (monomer) represented by the formula (I-6) are bonded). The combination of the respective constituent components is appropriately selected depending on the kind of the polymer. One component in the combination of components refers to the number of types of components represented by any one of the following formulae, and even if there are two components represented by one of the following formulae, these components are not interpreted as two components.

[ chemical formula 7]

In the formula, R^P1And R^P2Each represents a molecular chain having a (mass average) molecular weight of 14 or more and 200,000 or less. The molecular weight of the molecular chain cannot be uniquely determined depending on the kind thereof, and the like, and is preferably 30 or more, more preferably 50 or more, and still more preferably100 or more, particularly preferably 150 or more. The upper limit is preferably 100,000 or less, and more preferably 10,000 or less. The mass average molecular weight of the molecular chain was measured for the raw material compound before being embedded in the main chain of the polymer.

Can be taken as R^P1And R^P2The molecular chain to be used is not particularly limited, but is preferably a hydrocarbon chain, a polyalkylene oxide chain, a polycarbonate chain or a polyester chain, more preferably a hydrocarbon chain or a polyalkylene oxide chain, and still more preferably a hydrocarbon chain, a polyethylene oxide chain or a polypropylene oxide chain.

Can be taken as R^P1And R^P2The hydrocarbon chain used herein refers to a hydrocarbon chain composed of carbon atoms and hydrogen atoms, and more specifically, refers to a structure in which at least two atoms (for example, hydrogen atoms) or groups (for example, methyl groups) in a compound composed of carbon atoms and hydrogen atoms are separated. In the present invention, the hydrocarbon chain also includes a chain having a group containing an oxygen atom, a sulfur atom or a nitrogen atom in the chain, such as a hydrocarbon group represented by the following formula (M2). The terminal group that can be present at the terminal end of the hydrocarbon chain is not included in the hydrocarbon chain. The hydrocarbon chain may have a carbon-carbon unsaturated bond, or may have a cyclic structure of an aliphatic ring and/or an aromatic ring. That is, the hydrocarbon chain may be any hydrocarbon chain composed of a hydrocarbon selected from the group consisting of aliphatic hydrocarbons and aromatic hydrocarbons.

As such a hydrocarbon chain, a double hydrocarbon chain including a chain composed of a hydrocarbon group of low molecular weight and a hydrocarbon chain composed of a hydrocarbon polymer (also referred to as a hydrocarbon polymer chain) may be used as long as the above molecular weight is satisfied.

The low-molecular-weight hydrocarbon chain is a chain composed of a normal (non-polymerizable) hydrocarbon group, and examples of the hydrocarbon group include an aliphatic or aromatic hydrocarbon group, and specifically, a group composed of an alkylene group (having preferably 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and still more preferably 1 to 3 carbon atoms), an arylene group (having preferably 6 to 22 carbon atoms, preferably 6 to 14 carbon atoms, and more preferably 6 to 10 carbon atoms), or a combination thereof is preferable. Can be formed as R^P2The hydrocarbon group of the low-molecular-weight hydrocarbon chain to be used is more preferably an alkylene group, still more preferably an alkylene group having 2 to 6 carbon atoms, and particularly preferably an alkylene group having 2 or 3 carbon atoms. The hydrocarbon chain may haveHaving a polymeric chain (e.g., (meth) acrylic polymer) as a substituent.

Examples of the aliphatic hydrocarbon group include a hydrogeno-reductor of an aromatic hydrocarbon group represented by the following formula (M2), a partial structure (for example, a group composed of isophorone) of a known aliphatic diisocyanate compound, and the like.

The aromatic hydrocarbon group is preferably a phenylene group or a hydrocarbon group represented by the following formula (M2).

[ chemical formula 8]

In the formula (M2), X represents a single bond, -CH₂-、-C(CH₃)₂-、-SO₂-, -S-, -CO-or-O-, preferably-CH from the viewpoint of adhesiveness₂-or-O-, more preferably-CH₂-. The alkylene group exemplified herein may be substituted with a halogen atom (preferably a fluorine atom).

R^M2～R^M5Each represents a hydrogen atom or a substituent, preferably a hydrogen atom. As can be R^M2～R^M5The substituent used is not particularly limited, and examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 1 to 20 carbon atoms, -OR^M6、-N(R^M6)₂、-SR^M6(R^M6The substituent preferably represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 10 carbon atoms. ) A halogen atom (e.g., a fluorine atom, a chlorine atom, a bromine atom). as-N (R)^M6)₂Examples thereof include alkylamino groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 6 carbon atoms) and arylamino groups (preferably having 6 to 40 carbon atoms, more preferably 6 to 20 carbon atoms).

The hydrocarbon polymer chain is a polymer chain obtained by polymerizing a polymerizable hydrocarbon (at least two hydrocarbons), and is not particularly limited as long as it is a chain composed of a hydrocarbon polymer having a carbon number larger than the low-molecular-weight hydrocarbon chain, and is preferably a chain composed of a hydrocarbon polymer having 30 or more carbon atoms, and more preferably 50 or more carbon atoms. The upper limit of the number of carbon atoms constituting the hydrocarbon polymer is not particularly limited, and may be, for example, 3,000. The hydrocarbon polymer chain is preferably a chain having a main chain composed of a hydrocarbon polymer composed of an aliphatic hydrocarbon satisfying the above carbon number, and more preferably a chain composed of a polymer (preferably an elastomer) composed of an aliphatic saturated hydrocarbon or an aliphatic unsaturated hydrocarbon. Specific examples of the polymer include diene polymers having a double bond in the main chain and non-diene polymers having no double bond in the main chain. Examples of the diene-based polymer include a styrene-butadiene copolymer, a styrene-ethylene-butadiene copolymer, a copolymer of isobutylene and isoprene (preferably, butyl rubber (IIR)), a butadiene polymer, an isoprene polymer, and an ethylene-propylene-diene copolymer. Examples of the non-diene polymer include olefin polymers such as ethylene-propylene copolymers and styrene-ethylene-butene copolymers, and hydrogen-reduced products of the diene polymers.

Can be taken as R^P1And R^P2The hydrocarbon chain used may have a substituent (for example, a substituent T described later or a functional group described in the functional group described later).

The hydrocarbon to be the hydrocarbon chain preferably has a reactive group at its terminal, and more preferably has a terminal reactive group capable of polycondensation. The terminal reactive group capable of polycondensation or addition polymerization is formed by polycondensation or addition polymerization to R of the formula^P1Or R^P2A bonded group. Examples of such a terminal reactive group include an isocyanate group, a hydroxyl group, a carboxyl group, and an amino group, and among them, a hydroxyl group is preferable.

As the hydrocarbon polymer having a terminal reactive group, for example, there are trade names, and NISSO-PB series (NIPPON SODA co., ltd., manufactured), clausol series (TOMOE ENGINEERING co., ltd., manufactured), PolyVEST-HT series (manufactured by Evonik Corporation), poly-bd series (Idemitsu Kosan co., manufactured by ltd., manufactured), poly-ip series (Idemitsu Kosan co., ltd., manufactured by ltd.), EPOL (Idemitsu Kosan co., manufactured by ltd., manufactured) and POLYTAIL series (manufactured by mitsubil Chemical Corporation) and the like can be preferably used.

In the above hydrocarbon chain, R^P1Preferably a low molecular weight hydrocarbon chain, more preferablyA hydrocarbon chain composed of an aromatic hydrocarbon group. R^P2The molecular chain or the aliphatic hydrocarbon group other than the low-molecular-weight hydrocarbon chain is preferable, and a mode in which the molecular chain or the aliphatic hydrocarbon group other than the low-molecular-weight hydrocarbon chain is contained is more preferable. In this embodiment, the constituent represented by the formula (I-3) or the constituent derived from the compound represented by any one of the formulae (I-4) and (I-6) preferably contains R^P2Is a constituent of a low molecular weight aliphatic hydrocarbon group and R^P2Is at least two of the constituent components of the molecular chain other than the low-molecular-weight hydrocarbon chain.

The number of carbon atoms of the alkyleneoxy group in the polyalkylene oxide chain (polyalkyleneoxy group) is preferably 1 to 10, more preferably 1 to 6, and further preferably 2 or 3 (polyethylene oxide chain or polypropylene oxide chain). The polyalkylene oxide chain may be a chain composed of one kind of polyalkylene oxide, or may be a chain composed of two or more kinds of polyalkylene oxides (for example, a chain composed of ethylene oxide and propylene oxide).

Examples of the polycarbonate chain or the polyester chain include chains composed of a known polycarbonate or polyester.

The polyalkylene oxide chain, polycarbonate chain or polyester chain preferably has an alkyl group (preferably 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms) at each end.

The alkyl group contained in the molecular chain may have an ether group (-O-), a thioether group (-S-), a carbonyl group (> C ═ O), or an imino group (> NR)^Na：R^NaA hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms).

In the above formulae, R^P1And R^P2The molecular chain has a valence of 2, but at least one hydrogen atom may be replaced by-NH-CO-, -O-, -NH-or-N-, and the molecular chain has a valence of 3 or more.

Specific examples of the constituent components represented by the above formula (I-1) are shown below. Examples of the raw material compound (diisocyanate compound) from which the constituent component represented by the formula (I-1) is derived include a diisocyanate compound represented by the formula (M1) described in international publication No. 2018/020827, specific examples thereof, and polymeric 4,4' -diphenylmethane diisocyanate. In the present invention, the constituent represented by the formula (I-1) and the raw material compound from which the constituent is derived are not limited to those described in the following specific examples and the above-mentioned documents.

[ chemical formula 9]

The starting compound (carboxylic acid or acid chloride thereof, etc.) from which the constituent component represented by the above formula (I-2) is derived is not particularly limited, and examples thereof include compounds of carboxylic acid or acid chloride described in [0074] of International publication No. 2018/020827, and specific examples thereof.

Specific examples of the constituent components represented by the above formula (I-3) are shown below. Examples of the raw material compounds (diol compound or diamine compound) for deriving the constituent components represented by the above formula (I-3) or formula (I-4) include, for example, each compound described in International publication No. 2018/020827 and specific examples thereof, and dihydroxyoxamide. In the present invention, the constituent represented by the formula (I-3) or the formula (I-4) and the raw material compound for deriving the constituent are not limited to those described in the following specific examples and the above-mentioned documents.

[ chemical formula 10]

In the formula (I-5), R^P3The linking group (4-valent) which represents an aromatic or aliphatic linking group is preferably a linking group represented by any one of the following formulae (i) to (iix).

[ chemical formula 11]

In formulae (i) to (iix), X¹Represents a single bond or a 2-valent linking group. The 2-valent linking group is preferably an alkylene group having 1 to 6 carbon atoms (e.g., methylene group, ethylene groupPropylene), or propylene. The propylene group is preferably a1, 3-hexafluoro-2, 2-propanediyl group. L represents-CH₂＝CH₂-or-CH₂-。R^XAnd R^YEach represents a hydrogen atom or a substituent. In each formula, a represents a bonding position to a carbonyl group in formula (1-5). As can be R^XAnd R^YThe substituent used is not particularly limited, and examples thereof include a substituent T described later, and preferably include an alkyl group (the number of carbon atoms is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 3) or an aryl group (the number of carbon atoms is preferably 6 to 22, more preferably 6 to 14, and even more preferably 6 to 10).

In the formula (I-6), R^b1～R^b4Represents a hydrogen atom or a substituent, preferably a hydrogen atom. Examples of the substituent include a substituent T described later, and an alkyl group is preferable.

The carboxylic dianhydride represented by the above formula (I-5) and the raw material compound (diamine compound) for deriving the constituent component represented by the above formula (I-6) are not particularly limited, and examples thereof include the compounds described in International publication No. 2018/020827 and International publication No. 2015/046313.

R^P1、R^P2And R^P3May have a substituent. The substituent is not particularly limited, and examples thereof include the substituent T described later and the ketone group of the functional group (I), and preferable examples thereof include R^M2The above-mentioned substituents are used.

The stepwise polymerization polymer has a constituent component represented by the following formula (H-1).

[ chemical formula 12]

In the formula, L¹¹Represents an alkylene group having 1 to 12 carbon atoms, an arylene group having 6 to 18 carbon atoms, an alkenylene group having 2 to 12 carbon atoms, a 2-valent heterocyclic group having 4 to 18 carbon atoms, an oxygen atom, a carbonyl group, or-N (R)^N) -or an imine linking group (-C (═ NR)^N) -) or combinations of these groups, atoms or linking groupsAnd (c) a group. X¹¹And X¹²Represents an oxygen atom, a sulfur atom or-N (R)^N) -. Wherein, X¹¹And X¹²Are different from each other. R^NRepresents a hydrogen atom, an alkylsilyl group, an aryl group having 6 to 18 carbon atoms or an alkyl group having 1 to 12 carbon atoms.

The alkylene group having 1 to 12 carbon atoms may be any of a linear, branched, cyclic, and combinations of at least two of these. In order to further improve the dispersibility of the solid electrolyte composition slurry and the battery performance, the alkylene group preferably includes a cyclic structure. Specific examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, an octylene group, a nonylene group, a decylene group, a cyclohexylene group, and a dodecenylene group. Further, an alkylene group in which a cyclohexylene group and an ethylene group are combined is also exemplified.

The number of carbon atoms of the arylene group having 6 to 18 carbon atoms is more preferably 6 to 10. Specific examples of the arylene group include a phenylene group and a naphthylene group.

The alkenylene group having 2 to 12 carbon atoms may be any of a linear, branched and cyclic one, and specific examples thereof include a vinylene group, a propenylene group and a 1-methylpropenylene group.

The heterocyclic ring constituting the heterocyclic group may be an aliphatic heterocyclic ring or an aromatic heterocyclic ring, and may be a single ring or a condensed ring. The hetero atom of the 2-valent heterocyclic group having 4 to 18 carbon atoms is not particularly limited, and examples thereof include an oxygen atom, a nitrogen atom and a sulfur atom. The number of hetero atoms contained in one hetero ring is not particularly limited, but is preferably 1 to 3, more preferably 1 or 2. The number of carbon atoms is preferably 4 to 10, more preferably 4 or 5. The heterocycle is preferably a 4-7 membered ring, more preferably a 5-or 6-membered ring. Specific examples of the heterocyclic ring include a pyrrolidine ring and a pyridine ring.

-N(R^N) -and an imine linkage group (-C (═ NR)^N) -) of^NPreferably represents a hydrogen atom. From R^NThe alkyl group of the alkylsilyl group has the same meaning as that of the alkyl group having 1 to 12 carbon atoms described below. From R^NThe alkyl group having 1 to 12 carbon atoms may be a straight chain or branched chainExamples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, and a cyclohexyl group. From R^NThe aryl group having 6 to 18 carbon atoms is more preferably 6 to 10 carbon atoms. Specific examples of the aryl group include a phenyl group and a naphthyl group.

The group formed by combining the group, atom or linking group is preferably a 2-valent group formed by combining 2 or 3 of the groups, and more preferably a 2-valent group formed by combining 2, and examples thereof include a 2-valent group formed by combining an alkylene group having 2 to 12 carbon atoms and an arylene group having 6 to 18 carbon atoms, a 2-valent group formed by combining a 2-valent heterocyclic group having 4 to 18 carbon atoms and an alkylene group having 2 to 12 carbon atoms, and a 2-valent group formed by combining an oxygen atom and an alkylene group having 2 to 12 carbon atoms.

The molecular weight of the combined group is not particularly limited, but is preferably 6000 or less, more preferably 1000 or less, more preferably 400 or less, and further preferably 300 or less. The lower limit of the molecular weight is preferably 40 or more, and more preferably 50 or more.

Can be taken as L¹¹The group to be used is appropriately determined in consideration of the length, rigidity, hydrophobicity (affinity for a dispersion medium described later) and the like of the molecular chain of each group, and from the viewpoint of dispersibility and battery characteristics, an alkylene group having 1 to 12 carbon atoms, an arylene group having 6 to 18 carbon atoms, or a 2-valent group in which these groups are combined is preferable, and an alkylene group having 1 to 12 carbon atoms is more preferable.

L¹¹May have a substituent. The substituent is not particularly limited, and has, for example, the same meaning as that of R^P1The substituents which may be present have the same meaning.

X¹¹And X¹²Each represents an oxygen atom, a sulfur atom or-N (R)^N1)-，R^N1Can be taken as L¹¹By the use of-N (R)^N1) R of (A-C)^N1The same meaning is true for (1), and a hydrogen atom is preferable.

X¹¹And X¹²Are each suitably selected from the above atoms and-N (R)^N1) -, but X¹¹And X¹²SelectingAtoms different from each other or-N (R)^N1) -. Thus, the above-mentioned interaction in which the step-polymerization type polymers act when the constituent component represented by the formula (H-1) is embedded in the step-polymerization type polymers can realize sufficient mechanical strength while suppressing the aggregation of the polymers. As a result, the dispersibility of the inorganic solid electrolyte composition and the battery performance of the all-solid secondary battery can be improved. X¹¹And X¹²The combination of (A) and (B) is not particularly limited, and is as described in X¹¹Or X¹²In the linkage with other constituent components, X¹¹And X¹²One of them shows a strong interaction as described above, X¹¹And X¹²The other exhibits a weaker interaction as described above.

At X¹¹Or X¹²In the linkage with other constituent components, the bond having a strong interaction includes, for example, a thiourea bond, a urea bond, and the like, and the bond having a weak interaction includes, for example, a thiocarbamate bond, a carbamate bond, an amide bond, a carbonate bond, an ester bond, and the like, and the strength of the interaction in these 5 bonds is thiocarbamate ≈ carbamate > amide > carbonate > ester. That is, the strength of the interaction between the thiocarbamate and the carbamate is the same, and becomes weaker in order from now on.

In the present invention, X is preferred¹¹And X¹²One of (A) is-N (R)^N1) -, the other is a sulfur atom or an oxygen atom, more preferably X¹¹And X¹²One of (A) is-N (R)^N1) -, another is an oxygen atom, particularly preferably X¹¹And X¹²One of them is-NH-and the other is an oxygen atom.

The constituent component represented by the formula (H-1) is a 2-valent constituent component, but in the present invention, a constituent component having a valence of 3 or more is included. As such a polyvalent constituent component, there may be mentioned removal of L¹¹The one or more hydrogen atoms are components to be inserted into a bonding portion of the polymer (to be bonded to other constituent components). The valence number of the constituent component in this case is preferably 3 to 8, more preferably 3 or 4.

And, bondingThe moiety may be an atom from which a hydrogen atom has been removed, or may be a linking group bonded to the atom. The linking group is not particularly limited, and examples thereof include an alkylene group having 2 to 12 carbon atoms, an arylene group having 6 to 18 carbon atoms, an alkenylene group having 2 to 12 carbon atoms, an oxygen atom, a sulfur atom and-N (R)^N1) -a silane linking group or an imine linking group or a combination of these groups, atoms or linking groups. The terminal bonding part of the linking group is preferably an oxygen atom, a sulfur atom or-N (R)^N1) -, more preferably an oxygen atom or a sulfur atom, and optionally X¹¹Or X¹²The same or different.

Specific examples of the constituent components represented by the above formula (H-1) are shown below.

The raw material compound from which the constituent is derived is not particularly limited, and examples thereof include an amino alcohol compound, an amino thiol compound, and a hydroxymercapto compound. These compounds can be appropriately synthesized, and commercially available products can be used.

[ chemical formula 13]

In order to further improve the dispersibility of the solid electrolyte composition slurry, the adhesion to solid particles, the ion conductivity of the solid electrolyte-containing sheet, and the battery performance, the step-polymerization-type polymer used in the present invention preferably has at least one functional group described in the following functional group set . These functional groups may be bonded to R of the constituent represented by the above formula (I-3) or formula (I-4)^P2The bond may be to other groups.

< group of functional groups (I) >)

Carboxyl group and sulfonic group (-SO)₃H) Keto group, phosphate group (phosphate group, -OPO)₃H₂)

(Structure of step-by-step polymerization-based Polymer)

The stepwise polymerization type polymer preferably has a constituent component represented by the formula (H-1) among the constituent components represented by the above formulae and a constituent component represented by the above formula (I-3) orA constituent component represented by the formula (I-4). The constituent component represented by the formula (I-3) preferably has R^P2The molecular chain is preferably a constituent of the polycarbonate chain, the polyester chain, or the polyalkylene oxide chain (a constituent represented by the following formula (I-3B)), and more preferably has R^P2A constituent component (a constituent component represented by the following formula (I-3A)) which is a hydrocarbon group (preferably a group having at least one functional group represented by the functional group ) and R^P2The molecular chain is at least one of the constituent components of the hydrocarbon polymer chain (constituent components represented by the following formula (I-3C)).

Specifically, the stepwise polymerization polymer preferably has a constituent represented by the following formula (I-1) or formula (I-2), a constituent represented by the following formula (I-3B) and a constituent represented by the following formula (H-1), more preferably has a constituent represented by the following formula (I-3C) or formula (I-3A), and still more preferably has a constituent represented by the following formula (I-3C) and formula (I-3A) in addition to these constituents.

[ chemical formula 14]

In the formulae (I-1) and (I-2), R^P1As described above.

In the formula (I-3A), R^P2ARepresents a hydrocarbon group, preferably having at least one functional group described in the functional group . For example, a bis (hydroxymethyl) acetic acid compound such as 2, 2-bis (hydroxymethyl) butanoic acid is exemplified. In the formula (I-3B), R^P2BRepresents a polycarbonate chain, a polyester chain or a polyalkylene oxide chain. In the formula (I-3C), R^P2CRepresents a hydrocarbon polymer chain. Can be taken as R^P2AThe hydrocarbyl radical adopted can be R^P2BPolycarbonate chains, polyester chains, polyalkylene oxide chains and the like which can be used as R^P2CThe hydrocarbon polymer chains used have the same meanings as those in the above formula (I-3) capable of being represented by R^P2The hydrocarbon group, polycarbonate chain, polyester chain, polyalkylene oxide chain and hydrocarbon polymer chain used are the same as defined above, and preferably the same.

In the formula (H-1), L¹¹、X¹¹And X¹²As described above.

In the step-polymerization-based polymer, the combination of the constituent components represented by the above formulae is not particularly limited, and preferred components of the constituent components represented by the formulae may be appropriately combined with each other. For example, the following preferred combinations of the constituent components can be mentioned.

A constituent represented by the formula (I-1): constituent derived from diphenylmethane diisocyanate, constituent derived from dicyclohexylmethane 4,4' -diisocyanate

A constituent represented by the formula (I-2): constituent derived from terephthalic acid diacid dichloride compound

A constituent represented by the formula (I-3A): constituent derived from 2, 2-bis (hydroxymethyl) butanoic acid compound, constituent derived from 2, 2-bis (hydroxymethyl) propionic acid, constituent derived from propylene glycol, constituent derived from 1, 4-butanediol

A constituent represented by the formula (I-3B): polyethylene glycol or polypropylene glycol-derived component, and polytetramethylene glycol-derived component

A constituent represented by the formula (I-3C): constituent derived from (hydrogenated) polybutadiene, constituent derived from (hydrogenated) polyisoprene

A constituent represented by the formula (H-1): constituent derived from compound used in the above-mentioned specific examples or examples, constituent derived from aminoalcohol

The stepwise polymerization type polymer used in the present invention may have a constituent component other than the constituent components represented by the above formulae. Such a constituent component is not particularly limited as long as it can be gradually polymerized with the constituent components represented by the above formulae.

The content (in total) of the constituent components represented by any one of the above formulae (H-1) and (1-1) to (I-6) in the stepwise polymerizable polymer is not particularly limited, but is preferably 5 to 100% by mass, more preferably 10 to 100% by mass, even more preferably 50 to 100% by mass, and even more preferably 80 to 100% by mass. The upper limit of the content is not limited to 100% by mass, and may be, for example, 90% by mass or less.

The content of the constituent components other than the constituent components represented by the above formulae in the stepwise polymerization type polymer is not particularly limited, and is preferably 80% by mass or less.

The content of the constituent component represented by the above formula (H-1) in the stepwise polymerization polymer is not particularly limited, and the lower limit is preferably 0.001% by mass or more, more preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and further preferably 1% by mass or more. The upper limit is preferably 50% by mass or less, more preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less.

When the stepwise polymerization type polymer has a constituent component represented by any one of the above formulas (I-1) to (I-6), the content thereof is not particularly limited, and can be set in the following range.

That is, the content of the constituent component represented by the formula (I-1) or the formula (I-2) or the constituent component derived from the carboxylic dianhydride represented by the formula (I-5) in the stepwise polymerization polymer is not particularly limited, and the lower limit is preferably 0% by mass or more, more preferably 0.01% by mass or more, more preferably 0.1% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more. The upper limit is preferably 70% by mass or less, more preferably 65% by mass or less, more preferably 60% by mass or less, more preferably 50% by mass or less, and further preferably 40% by mass or less.

The content of the constituent component represented by the formula (I-3), the formula (I-4) or the formula (I-6) in the stepwise polymerization type polymer is not particularly limited, and the lower limit is preferably 0% by mass or more, more preferably 5% by mass or more, more preferably 15% by mass or more, more preferably 25% by mass or more, and further preferably 35% by mass. The upper limit is preferably 80% by mass or less, more preferably 70% by mass or less, and still more preferably 65% by mass or less.

In the constituent component represented by the formula (I-3) or the formula (I-4), R^P2Is a constituent of a hydrocarbon group (preferably a constituent having at least one functional group described in the functional group , e.g.The content of the constituent component represented by the above formula (I-3A) in the stepwise polymerization type polymer is not particularly limited, and for example, the lower limit is preferably 0% by mass or more, more preferably 0.1% by mass or more, and further preferably 1% by mass or more. The upper limit is preferably 50% by mass or less, more preferably 30% by mass or less, more preferably 10% by mass or less, and more preferably 5% by mass or less.

In the constituent component represented by the formula (I-3) or the formula (I-4), R^P2The content of the constituent (for example, the constituent represented by the formula (I-3B)) having a molecular chain of the polycarbonate chain, the polyester chain or the polyalkylene oxide chain in the stepwise polymerization polymer is not particularly limited, and for example, the lower limit is preferably 0% by mass or more, more preferably 0.1% by mass or more, and further preferably 10% by mass or more. The upper limit is preferably 70% by mass or less, more preferably 60% by mass or less, more preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less.

In the constituent component represented by the formula (I-3) or the formula (I-4), R^P2The content of the constituent (for example, the constituent represented by the formula (I-3C)) having a molecular chain that is the above-mentioned hydrocarbon polymer chain in the stepwise polymerization-based polymer is not particularly limited, and for example, the lower limit is preferably 0% by mass or more, more preferably 5% by mass or more, and further preferably 10% by mass or more. The upper limit is preferably 80% by mass or less, more preferably 60% by mass or less, more preferably 50% by mass or less, and further preferably 45% by mass or less.

In the case where the stepwise polymerization type polymer has a plurality of constituent components represented by each formula, the content of each constituent component is defined as the total content.

The structure of the stepwise polymerization polymer will be described with respect to a partial structure containing the constituent component represented by the above formula (H-1) (not a constituent component corresponding to the constituent component derived from the raw material compound but a constituent component represented by a bonding portion specific in the present invention).

The partial structure containing the constituent component represented by the formula (H-1) is not uniquely determined depending on the other constituent component bonded to the constituent component represented by the formula (H-1), and in the present invention, the partial structure represented by the following formula (H-2) is preferable, and the partial structure represented by the following formula (H-3) is more preferable.

[ chemical formula 15]

In the formula, L²¹The meaning of (1) and the above-mentioned L¹¹The same meanings are given above, and preferred ranges are also the same. R^N2Has the meaning of R^N1The same meanings are given above, and preferred ranges are also the same. The bond portion for introducing a partial structure into the stepwise polymerization-based polymer is represented.

This partial structure is a partial structure composed of an example of the constituent component represented by the formula (H-1) and carbonyl groups of another constituent component (for example, a constituent component represented by the formula (H-1) or the formula (H-2)) bonded to both ends of the constituent component. In this partial structure, with L²¹Bonded bonds (-COO-bonds and-CONR)^N2-) different from each other, in the stepwise polymerization type polymer, L is²¹One of the double bonds sandwiched in between shows the stronger interaction described above, the other shows the weaker interaction. Therefore, it is considered that the above partial structure suppresses strong interaction (aggregation) between polymers caused by double bonds, and shows interaction suitable for the present invention.

[ chemical formula 16]

L³¹The group has a molecular weight of 400 or less (preferably 300 or less, preferably 40 or more, and more preferably 50 or more) and is a C1-12 alkylene group, a C6-12 arylene group, an oxygen atom, an imine linking group, or a combination of these groups, atoms, or linking groups. The bond portion for introducing a partial structure into the stepwise polymerization-based polymer is represented.

The partial structure is composed ofAn example of the constituent component represented by (H-1), and a partial structure composed of-NHCO-groups of other constituent components (the constituent component represented by the above formula (H-1)) bonded to both ends of the constituent component. In this partial structure, with L³¹The bonded urethane bond shows the above-mentioned weak interaction, and the urea bond shows a strong interaction, and by this partial structure, the mechanical strength of the polymer can be maintained, and the strong interaction (cohesive force) between the polymers can be suppressed from being expressed.

The step-polymerization polymer used in the present invention is preferably a polymer represented by the following formula in order to further improve dispersibility of the solid electrolyte composition slurry, ion conductivity of the solid electrolyte-containing sheet, and battery performance.

[ chemical formula 17]

In the formula, L¹With R^P1The same meanings are given above, and preferred ranges are also the same.

X¹、X²And L²Are each as defined in (1) and X¹¹、X¹²And L¹¹The same meanings are given above, and preferred ranges are also the same.

X³And X⁴Both represent-NH-or an oxygen atom, preferably an oxygen atom. L is³With R^P2AThe same meanings are given above, and preferred ranges are also the same.

X⁵And X⁶Both represent-NH-or an oxygen atom, preferably an oxygen atom. L is⁴With R^P2BThe same meanings are given above, and preferred ranges are also the same.

X⁷And X⁸Both represent-NH-or an oxygen atom, preferably an oxygen atom. L is⁵With R^P2CThe same meanings are given above, and preferred ranges are also the same.

In the formula, s1 to s5 represent the content (% by mass) of each constituent component, and the total is 100% by mass. The total of s2 to s5 exceeds 0% by mass.

The lower limit of s1 is preferably more than 0% by mass, more preferably 0.01% by mass or more, still more preferably 0.1% by mass or more, still more preferably 10% by mass or more, and still more preferably 15% by mass or more. The upper limit of s1 is preferably 70% by mass or less, more preferably 65% by mass or less, more preferably 60% by mass or less, more preferably 50% by mass or less, and still more preferably 40% by mass or less.

The lower limit of s2 is preferably 0.001% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.3% by mass or more, and still more preferably 1% by mass or more. The upper limit of s2 is preferably 50% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, and still more preferably 3% by mass or less.

The lower limit of s3 is preferably 0% by mass or more, more preferably 0.1% by mass or more, and still more preferably 1% by mass or more. The upper limit of s3 is preferably 50% by mass or less, more preferably 30% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass or less.

The lower limit of s4 is preferably 0% by mass or more, more preferably 0.1% by mass or more, and still more preferably 10% by mass or more. The upper limit is preferably 70% by mass or less, more preferably 60% by mass or less, more preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less.

The lower limit of s5 is preferably 0% by mass or more, more preferably 5% by mass or more, and still more preferably 10% by mass or more. The upper limit of s5 is preferably 80% by mass or less, more preferably 60% by mass or less, more preferably 50% by mass or less, and still more preferably 45% by mass or less.

In the formula, the constituent components corresponding to the respective constituent components represented by the formulae with s1 to s5 may have the same structure or different structures. For example, the above-mentioned polymer has L¹In the case of constituent components having different structures from each other, the total content of these constituent components is s 1.

Specific examples of the step-polymerization type polymer used in the present invention include the polymers synthesized in examples and the following compounds.

The stepwise polymerization type polymer (each constituent component) may have a substituent. Examples of the substituent include a group selected from the following substituents T. The substituent T is not limited to the following examples.

An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, for example, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a pentyl group, a heptyl group, a 1-ethylpentyl group, a benzyl group, a 2-ethoxyethyl group, a 1-carboxymethyl group, etc.), an alkenyl group (preferably an alkenyl group having 2 to 20 carbon atoms, for example, a vinyl group, an allyl group, an oleyl group, etc.), an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, for example, an ethynyl group, a butadiynyl group, a phenylethynyl group, etc.), a cycloalkyl group (preferably a cycloalkyl group having 3 to 20 carbon atoms, for example, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a 4-methylcyclohexyl group, etc.), an aryl group (preferably an aryl group having 6 to 26 carbon atoms, for example, a phenyl group, 1-naphthyl group, a 4-methoxyphenyl group, 2-chlorophenyl group, a 3-methylphenyl group, etc.), a heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, preferably a 5-or 6-membered ring having at least one oxygen atom, sulfur atom, nitrogen atom. The heterocyclic group includes an aromatic heterocyclic group and an aliphatic heterocyclic group. Examples thereof include tetrahydropyranyl ring group, tetrahydrofuranyl ring group, 2-pyridyl group, 4-pyridyl group, 2-imidazolyl group, 2-benzimidazolyl group, 2-thiazolyl group, 2-oxazolyl group and the like, alkoxy group (preferably alkoxy group having 1 to 20 carbon atoms, for example, methoxy group, ethoxy group, isopropoxy group, benzyloxy group and the like), aryloxy group (preferably aryloxy group having 6 to 26 carbon atoms, for example, phenoxy group, 1-naphthoxy group, 3-methylphenoxy group, 4-methoxyphenoxy group and the like), heterocyclic oxy group (group having the above-mentioned heterocyclic group to which-O-group is bonded), alkoxycarbonyl group (preferably alkoxycarbonyl group having 2 to 20 carbon atoms, for example, ethoxycarbonyl group, 2-ethylhexyloxycarbonyl group and the like), aryloxycarbonyl group (preferably aryloxycarbonyl group having 6 to 26 carbon atoms, aryloxy group, For example, phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), amino group (preferably containing 0 to 20 carbon atoms of amino, alkylamino, arylamino, e.g., (-NH)₂) N, N-dimethylamino group, N-diethylamino group, N-ethylamino group, anilino group, etc.), a sulfamoyl group (preferably a sulfamoyl group having 0 to 20 carbon atoms),For example, N, N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), an acyl group (including alkylcarbonyl, alkenylcarbonyl, alkynylcarbonyl, arylcarbonyl, heterocyclic carbonyl, preferably an acyl group having 1 to 20 carbon atoms, for example, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonyl, benzoyl, naphthoyl, nicotinoyl, etc.), an acyloxy group (including alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, arylcarbonyloxy, heterocyclic carbonyloxy, preferably an acyloxy group having 1 to 20 carbon atoms, for example, acetoxy, propionyloxy, butyryloxy, octanoyloxy, hexadecanoyloxy, acryloyloxy, methacryloyloxy, crotonyloxy, benzoyloxy, naphthoyloxy, nicotinoyloxy, etc.), an aroyloxy group (preferably an aroyloxy group having 7 to 23 carbon atoms, an aroyloxy group having a, octanoyloxy, nicotinoyloxy, etc.), or a salt thereof, For example, benzoyloxy group or the like), a carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, for example, N, N-dimethylcarbamoyl group, N-phenylcarbamoyl group or the like), an acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, for example, acetylamino group, benzoylamino group or the like), an alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, for example, methylthio group, ethylthio group, isopropylthio group, benzylthio group or the like), an arylthio group (preferably an arylthio group having 6 to 26 carbon atoms, for example, phenylthio group, 1-naphthylthio group, 3-methylphenylthio group, 4-methoxyphenylthio group or the like), a heterocyclic thio group (-S-group) to which the above-mentioned heterocyclic group is bonded, an alkylsulfonyl group (preferably an alkylsulfonyl group having 1 to 20 carbon atoms, for example, methylsulfonyl group, ethylsulfonyl group or the like), Arylsulfonyl (preferably arylsulfonyl having 6 to 22 carbon atoms, for example, phenylsulfonyl), alkylsilyl (preferably alkylsilyl having 1 to 20 carbon atoms, for example, monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl and the like), arylsilyl (preferably arylsilyl having 6 to 42 carbon atoms, for example, triphenylsilyl and the like), phosphoryl (preferably phosphoric acid group having 0 to 20 carbon atoms, for example, -OP (═ O) (R)^P)₂) A phosphono group (preferably a phosphono group having 0 to 20 carbon atoms, for example, -P (═ O) (R)^P)₂) A phosphinyl group (preferably a phosphinyl group having 0 to 20 carbon atoms, e.g., -P (R)^P)₂) A sulfo group (sulfonic acid group), a carboxyl group, a hydroxyl group, a sulfanyl group, a cyano group, and a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.). R^PIs a hydrogen atom or a substituent (preferably a group selected from the substituent T).

And, each group listed in these substituents T may be further substituted with the above-mentioned substituents T.

The compound, the substituent, the linking group and the like include an alkyl group, an alkylene group, an alkenyl group, an alkenylene group, an alkynyl group, an alkynylene group and/or the like, and they may be cyclic or linear, and may be linear or branched.

(Properties and Properties of stepwise polymerization Polymer)

The urea value of the step-polymerization-based polymer used in the present invention is not particularly limited, and is preferably more than 0mmol/g, more preferably 0.03mmol/g or more, and still more preferably 0.05mmol/g or more, in order to improve dispersibility of solid electrolyte composition slurry, ionic conductivity of the solid electrolyte-containing sheet, adhesiveness in constituent layers, and battery performance. The upper limit is preferably 0.5mmol/g or less, more preferably 0.45mmol/g or less, and still more preferably 0.35mmol/g or less.

The urea value can be calculated by the measurement method described in the examples below.

The mass average molecular weight of the stepwise polymerizable polymer contained in the binder is not particularly limited, but is preferably 5,000 or more, more preferably 10,000 or more, and particularly preferably 15,000 or more. The upper limit is preferably 1,000,000 or less, more preferably 500,000 or less, and still more preferably 200,000 or less. Further, it is preferable to introduce a crosslinked structure so that the molecular weight is not less than the measurement limit.

(Synthesis of stepwise polymerization type Polymer)

The stepwise polymerization polymer can be synthesized by deriving raw material compounds of predetermined constituent components in an arbitrary combination depending on the kind of the main chain and, if necessary, stepwise polymerizing the raw material compounds in the presence of a catalyst (for example, an organotin-containing catalyst). The method and conditions for the stepwise polymerization are not particularly limited, and known methods and conditions can be appropriately selected. The properties and physical properties of the stepwise polymerization type polymer can be adjusted by the type of the stepwise polymerization type polymer, the type or content of the constituent component (raw material compound), the molecular weight of the polymer, and the like. The starting compound is a known compound appropriately selected according to the type of the stepwise polymerization type polymer. For example, in addition to the above-mentioned raw material compounds, there can be mentioned raw material compounds which form a polymer having a urethane bond, a polymer having a urea bond, a polymer having an Amide (Amide) bond (polyamide resin), a polymer having an Imide (Imide) bond, and the like, as described in Japanese patent laid-open publication No. 2015-088480.

The solvent used in the synthesis of the stepwise polymerization polymer is not particularly limited, and a solvent exemplified as a dispersion medium described later can be preferably used. In the present invention, when a dispersion of a stepwise polymerization polymer is prepared by a phase inversion emulsification method (in the case of preparing a binder) described later, it is preferable to use a method in which a solvent used in synthesizing the stepwise polymerization polymer (in the case of preparing a stepwise polymerization polymer solution) is replaced with a dispersion medium capable of emulsifying and dispersing the stepwise polymerization polymer, and the solvent used in synthesizing the stepwise polymerization polymer is removed. In this method, the boiling point of the solvent used for synthesizing the stepwise polymerization type polymer is preferably lower than the boiling point of the dispersion medium capable of emulsifying and dispersing the stepwise polymerization type polymer. As the dispersion medium capable of emulsifying and dispersing the stepwise polymerizable polymer, a dispersion medium capable of emulsifying and dispersing the stepwise polymerizable polymer, which will be described later, can be preferably used.

(preparation of Dispersion of stepwise polymerization Polymer)

The method for producing the dispersion of the stepwise polymerization type polymer is not particularly limited, and the dispersion can be produced by synthesizing the stepwise polymerization type polymer (for example, emulsion polymerization method), or by dispersing the synthesized stepwise polymerization type polymer in an appropriate dispersion medium. Examples of the method of dispersing the step-polymerization-based polymer in the dispersion medium include a method using a flow reactor (a method of colliding primary particles of the step-polymerization-based polymer with each other), a method of stirring with a homogenizer, a phase inversion emulsification method, and the like. Among them, from the viewpoint of productivity and from the viewpoint of the characteristics, physical properties and the like of the step-polymerization polymer to be obtained, a method of phase-inversion emulsifying the synthesized step-polymerization polymer is preferable.

The phase inversion emulsification method comprises a step of dispersing the stepwise polymerization polymer and a step of removing the solvent used in the synthesis of the stepwise polymerization polymer. Examples of the step of dispersing the polymer include a method of emulsifying by dropping a solution of the stepwise polymerization polymer (for example, at-20 to 150 ℃ for 0.5 to 8 hours) into a dispersion medium capable of emulsifying and dispersing the stepwise polymerization polymer, and a method of emulsifying by dropping a dispersion medium capable of emulsifying and dispersing the stepwise polymerization polymer slowly while strongly stirring the solution of the stepwise polymerization polymer. The step of removing the solvent may be a method of heating the thus-obtained dispersion of the stepwise polymerization polymer under reduced pressure or under an inert gas flow. Thus, the solvent used in synthesizing the stepwise polymerization type polymer can be selectively removed, and the concentration of the dispersion medium in which the stepwise polymerization type polymer can be emulsified and dispersed can be increased.

In the present invention, the "strong stirring" is not particularly limited as long as mechanical energy such as impact, shear stress, friction, vibration, and the like is applied to the polymer solution. For example, a system in which stirring is performed at a rotation speed of 300 to 1000rpm or the like using a homogenizer, a homogenizing disperser, a shaker, a dissolver, a TAITEC mixer, a stirring blade in a stirring tank, a high-pressure jet disperser, an ultrasonic disperser, a ball mill, a bead mill or the like is exemplified. The "slow dropping" is not particularly limited as long as it is not added together, and examples thereof include a condition in which the dropping dispersion medium is dropped and mixed into the stepwise polymerization polymer solution over 10 minutes or more.

The dispersion medium capable of emulsifying and dispersing the stepwise polymerizable polymer is suitably determined depending on the kind of the constituent components of the stepwise polymerizable polymer, and the like. For example, in the case of containing a component having a hydrocarbon polymer chain, there may be mentioned a solvent in which the component is easily dissolved and other components such as the component represented by the formula (I-1) are hardly dissolved. Such a solvent is not particularly limited, and among the dispersion media described later, nonaqueous dispersion media (aliphatic compounds and aromatic compounds) are preferable. Examples of the aliphatic compound include hexane, heptane, n-octane, isooctane, nonane, decane, dodecane, cyclohexane, cycloheptane, cyclooctane, methylcyclohexane, ethylcyclohexane, decahydronaphthalene, gas oil, kerosene, and gasoline. Examples of the aromatic compound include benzene, toluene, ethylbenzene, xylene, mesitylene, and tetrahydronaphthalene. One kind of the dispersion medium may be used alone, or two or more kinds may be used. Polar solvents (ether solvents, ketone solvents, ester solvents, etc.) may be added and used as long as they do not inhibit the emulsification and dispersion of the polymer. The mass ratio of the nonaqueous dispersion medium to the polar solvent [ mass of nonaqueous dispersion medium/mass of polar solvent ] is preferably 100/0 to 70/30, more preferably 100/0 to 90/10, and most preferably 100/0 to 99/1.

The boiling point of the dispersion medium capable of emulsifying and dispersing the stepwise polymerizable polymer under normal pressure is preferably 80 ℃ or higher, preferably 70 ℃ or higher, and preferably 80 ℃ or higher.

In the phase inversion emulsification method, the average particle diameter of the particles of the stepwise polymerization polymer can be prepared by the solid content concentration or the dropping speed of the stepwise polymerization polymer solution to be used, the kind of the stepwise polymerization polymer, the kind or content of the constituent component, and the like.

< dispersing Medium >

The solid electrolyte composition of the present invention contains a dispersion medium.

The dispersion medium may be any medium that disperses or dissolves the above components, and is preferably a medium that disperses the above components without dissolving at least the binder. Examples of the dispersion medium contained in the solid electrolyte composition include various organic solvents. Examples of the organic solvent include alcohol compounds, ether compounds, amide compounds, amine compounds, ketone compounds, aromatic compounds, aliphatic compounds, nitrile compounds, ester compounds, and the like, and specific examples of the dispersion medium include the following media.

Examples of the alcohol compound include methanol, ethanol, 1-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.

Examples of the ether compound include alkylene glycol alkyl ethers (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol, polyethylene glycol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, etc.), dialkyl ethers (dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, etc.), cyclic ethers (tetrahydrofuran, dioxane (including 1,2-, 1,3-, and 1, 4-isomers), and the like).

Examples of the amide compound include N, N-dimethylformamide, N-methyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, epsilon-caprolactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N-dimethylacetamide, N-methylpropanamide, hexamethylphosphoric triamide, and the like.

Examples of the amine compound include triethylamine, diisopropylethylamine, and tri-n-butylamine.

Examples of the ketone compound include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and diisobutyl ketone.

Examples of the aromatic compound include benzene, toluene, and xylene.

Examples of the aliphatic compound include hexane, heptane, octane, and decane.

Examples of the nitrile compound include acetonitrile, propionitrile, and isobutyronitrile.

Examples of the ester compound include ethyl acetate, butyl acetate, propyl acetate, butyl butyrate, and butyl valerate.

Examples of the nonaqueous dispersion medium include the aromatic compound and the aliphatic compound.

In the present invention, among them, ketone compounds, aromatic compounds, aliphatic compounds and ester compounds are preferable, and ketone compounds, aliphatic compounds and ester compounds are more preferable. In the present invention, it is preferable to use a sulfide-based inorganic solid electrolyte, and the specific organic solvent is selected. By selecting such a combination, the sulfide-based inorganic solid electrolyte can be stably handled because the sulfide-based inorganic solid electrolyte does not contain a functional group that is active for the sulfide-based inorganic solid electrolyte. A combination of a sulfide-based inorganic solid electrolyte and an aliphatic compound is particularly preferable.

The boiling point of the dispersion medium at normal pressure (1 atm) is preferably 50 ℃ or higher, more preferably 70 ℃ or higher. The upper limit is preferably 250 ℃ or lower, and more preferably 220 ℃ or lower.

The solid electrolyte composition may contain one dispersion medium, or may contain two or more kinds.

In the present invention, the content of the dispersion medium in the solid electrolyte composition is not particularly limited and can be appropriately set. For example, the solid electrolyte composition is preferably 20 to 99% by mass, more preferably 30 to 90% by mass, and particularly preferably 40 to 80% by mass.

< conductive assistant >

The solid electrolyte composition of the present invention can contain a conduction aid, and particularly, a silicon atom-containing active material as a negative electrode active material is preferably used together with the conduction aid.

The conductive aid is not particularly limited, and a conductive aid generally known as a conductive aid can be used. For example, natural graphite, artificial graphite and other graphites, acetylene black, Ketjen black (Ketjen black), furnace black and other carbon blacks, needle coke and other amorphous carbons, vapor grown carbon fibers, carbon nanotubes and other carbon fibers, graphene, fullerene and other carbonaceous materials, metal powders, metal fibers, such as copper and nickel, metal fibers, polyaniline, polypyrrole, polythiophene, polyacetylene, polyphenylene derivatives and other conductive polymers may be used as the electron conductive material.

In the present invention, when the active material and the conductive assistant are used together, the conductive assistant does not cause Li insertion and release during charging and discharging of the battery, and a material that does not function as an active material is used as the conductive assistant. Therefore, among the conductive aids, those capable of exerting the function of the active material in the active material layer at the time of charging and discharging the battery are classified as active materials rather than conductive aids. Whether or not to function as an active material when charging and discharging the battery is determined by combination with the active material, not uniquely.

One or more kinds of the conductive aids may be used.

The total content of the conductive auxiliary in the electrode layer composition is preferably 0.1 to 30% by mass, and more preferably 0.5 to 20% by mass, based on the total solid content.

The shape of the conductive aid is not particularly limited, and is preferably a particle shape. The median particle diameter D50 of the conductive assistant is not particularly limited, and is preferably 0.01 to 1 μm, and more preferably 0.02 to 0.1. mu.m.

< active substance >

The solid electrolyte composition of the present invention may also contain an active material capable of intercalating and releasing ions of metal elements belonging to group 1 or group 2 of the periodic table.

Examples of the active material include a positive electrode active material and a negative electrode active material, and a transition metal oxide as the positive electrode active material or a metal oxide as the negative electrode active material is preferable.

In the present invention, a solid electrolyte composition containing active materials (a positive electrode active material and a negative electrode active material) may be referred to as an electrode composition (a positive electrode composition and a negative electrode composition).

(Positive electrode active Material)

The positive electrode active material that the solid electrolyte composition of the present invention may contain is preferably capable of reversibly intercalating and deintercalating lithium ions. The material is not particularly limited as long as it has the above-mentioned characteristics, and may be an element capable of forming a composite with Li, such as a transition metal oxide, an organic substance, or sulfur, or a composite of sulfur and a metal.

Among them, transition metals are preferably used as the positive electrode active materialOxide, more preferably having a transition metal element M^a(one or more elements selected from Co, Ni, Fe, Mn, Cu and V). Further, the transition metal oxide may be mixed with the element M^b(an element of group 1(Ia), an element of group 2(IIa), Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, B, or the like of the periodic Table of metals other than lithium). The amount to be mixed is preferably in relation to the transition metal element M^aThe amount (100 mol%) of the (C) component is 0 to 30 mol%. More preferably as Li/M^aIs mixed so that the molar ratio of (A) to (B) is 0.3 to 2.2.

Specific examples of the transition metal oxide include (MA) a transition metal oxide having a layered rock-salt structure, (MB) a transition metal oxide having a spinel structure, (MC) a lithium-containing transition metal phosphate compound, (MD) a lithium-containing transition metal halophosphoric acid compound, and (ME) a lithium-containing transition metal silicate compound.

Specific examples of (MA) the transition metal oxide having a layered rock-salt structure include LiCoO₂(lithium cobaltate [ LCO ]])、LiNi₂O₂(lithium nickelate) and LiNi_0.85Co_0.10Al_0.05O₂(Nickel cobalt lithium aluminate [ NCA)])、LiNi_1/3Co_1/3Mn_1/ ₃O₂(lithium nickel manganese cobaltate [ NMC ]]) And LiNi_0.5Mn_0.5O₂(lithium manganese nickelate).

Specific examples of (MB) transition metal oxides having a spinel structure include LiMn₂O₄(LMO)、LiCoMnO₄、Li₂FeMn₃O₈、Li₂CuMn₃O₈、Li₂CrMn₃O₈And Li₂NiMn₃O₈。

Examples of the (MC) lithium-containing transition metal phosphate compound include LiFePO₄And Li₃Fe₂(PO₄)₃Isoolivine-type iron phosphate salt, LiFeP₂O₇Iso-pyrophosphoric acid iron species, LiCoPO₄Isophosphoric acid cobalt compounds and Li₃V₂(PO₄)₃Monoclinic NASICON-type vanadium phosphate salts such as (lithium vanadium phosphate).

Examples of the (MD) lithium-containing transition metal halophosphor compound include Li₂FePO₄F, etc. iron fluorophosphate, Li₂MnPO₄F, etc. manganese fluorophosphate and Li₂CoPO₄And cobalt fluorophosphates such as F.

Examples of the (ME) lithium-containing transition metal silicate compound include Li₂FeSiO₄、Li₂MnSiO₄And Li₂CoSiO₄And the like.

In the present invention, (MA) a transition metal oxide having a layered rock-salt type structure is preferable, and LCO, LMO, NCA or NMC is more preferable.

The shape of the positive electrode active material is not particularly limited, and is preferably a particle shape. The volume average particle diameter (sphere-equivalent average particle diameter) of the positive electrode active material is not particularly limited. For example, the thickness can be set to 0.1 to 50 μm. In order to make the positive electrode active material have a predetermined particle size, a general pulverizer or classifier may be used. The positive electrode active material obtained by the firing method may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, and an organic solvent. The volume average particle diameter (sphere-reduced average particle diameter) of the positive electrode active material particles can be measured using a laser diffraction/scattering particle size distribution measuring apparatus LA-920 (trade name, manufactured by HORIBA, ltd.).

The positive electrode active material may be used alone or in combination of two or more.

In the case of forming the positive electrode active material layer, the positive electrode active material layer has a unit area (cm)²) The mass (mg) (weight per unit area) of the positive electrode active material (b) is not particularly limited. The battery capacity can be determined as appropriate according to the designed battery capacity.

The content of the positive electrode active material in the solid electrolyte composition is not particularly limited, and is preferably 10 to 95 mass%, more preferably 30 to 90 mass%, still more preferably 50 to 85 mass%, and particularly preferably 55 to 80 mass% of 100 mass% of the solid content.

(negative electrode active Material)

The negative electrode active material is preferably a negative electrode active material capable of reversibly intercalating and deintercalating lithium ions. The material is not particularly limited as long as it has the above-described characteristics, and examples thereof include a carbonaceous material, a metal oxide, a metal composite oxide, a silicon-based material, a lithium monomer, a lithium alloy, and a negative electrode active material capable of forming an alloy with lithium. Among them, carbonaceous materials, metal composite oxides, and lithium monomers are preferably used from the viewpoint of reliability.

The carbonaceous material used as the negative electrode active material means a material substantially composed of carbon. Examples of the carbonaceous material include carbon materials obtained by firing various synthetic resins such as petroleum pitch, carbon black such as Acetylene Black (AB), graphite (e.g., artificial graphite such as natural graphite and vapor-phase-grown graphite), PAN (polyacrylonitrile) resin, and furfuryl alcohol resin. Further, various 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, mesophase microspheres, graphite whiskers, and tabular graphite can be cited.

The metal oxide and the metal composite oxide suitable as the negative electrode active material are not particularly limited as long as they are oxides capable of occluding and releasing lithium, and amorphous oxides are preferable, and chalcogenides which are reaction products of metal elements and elements of group 16 of the periodic table are also preferable. The amorphous substance as used herein refers to a material having a broad scattering band having an apex in a region having a 2 θ value of 20 ° to 40 ° by X-ray diffraction using CuK α rays, and may have a crystal diffraction line.

Among the group of compounds composed of the amorphous oxide and the chalcogenide, the amorphous oxide and the chalcogenide of a semimetal element are more preferable, and the oxide or the chalcogenide composed of an element of groups 13(IIIB) to 15(VB) of the periodic table, and one kind or a combination of two or more kinds of Al, Ga, Si, Sn, Ge, Pb, Sb, and Bi are particularly preferable. As preferred amorphous oxides and chalcogenidesSpecific examples thereof include Ga₂O₃、GeO、PbO、PbO₂、Pb₂O₃、Pb₂O₄、Pb₃O₄、Sb₂O₃、Sb₂O₄、Sb₂O₈Bi₂O₃、Sb₂O₈Si₂O₃、Sb₂O₅、Bi₂O₃、Bi₂O₄、GeS、PbS、PbS₂、Sb₂S₃And Sb₂S₅。

From the viewpoint of high current density charge/discharge characteristics, the metal (composite) oxide and the chalcogenide preferably contain at least one of titanium and lithium as a constituent component. Examples of the lithium-containing metal composite oxide (lithium composite metal oxide) include a composite oxide of acidified lithium and the metal (composite) oxide or the chalcogenide, and more specifically, Li₂SnO₂。

It is also preferable that the negative electrode active material contains a titanium atom. More particularly, due to Li₄Ti₅O₁₂(lithium titanate [ LTO ]]) Since the volume change at the time of occlusion and release of lithium ions is small, the lithium ion secondary battery is excellent in rapid charge and discharge characteristics, and is preferable in that the deterioration of the electrode is suppressed, and the life of the lithium ion secondary battery can be improved.

The lithium alloy as the negative electrode active material is not particularly limited as long as it is an alloy generally used as a negative electrode active material for a secondary battery, and examples thereof include a lithium aluminum alloy.

The negative electrode active material capable of forming an alloy with lithium is not particularly limited as long as it is a material that is generally used as a negative electrode active material for a secondary battery. Such an active material has a large expansion and contraction due to charge and discharge, and as described above, the adhesiveness of solid particles is lowered, but in the present invention, high adhesiveness can be achieved by the above adhesive. Examples of such active materials include a negative electrode active material having a silicon atom or a tin atom, and metals such as Al and In, preferably a negative electrode active material having a silicon atom (silicon atom-containing active material) capable of achieving a higher battery capacity, and more preferably a silicon atom-containing active material having a silicon atom content of 50 mol% or more of all constituent atoms.

In general, negative electrodes containing these negative electrode active materials (Si negative electrodes containing active materials containing silicon atoms, Sn negative electrodes containing active materials containing tin atoms) can adsorb Li ions more than carbon negative electrodes (graphite, acetylene black, and the like). That is, the amount of Li ions absorbed per unit mass increases. Therefore, the battery capacity can be increased. As a result, the battery driving time can be prolonged.

Examples of the silicon atom-containing active material include silicon materials such as Si and SiOx (0 < x.ltoreq.1), and alloys containing titanium, vanadium, chromium, manganese, nickel, copper, or lanthanum (e.g., LaSi)₂、VSi₂) Or organized active substances (e.g. LaSi)₂/Si), further, SnSiO₃、SnSiS₃And the like, silicon atoms and tin atoms. SiOx itself can be used as a negative electrode active material (semimetal oxide) and can be used as an active material (precursor material thereof) that can be alloyed with lithium because Si is generated by the operation of an all-solid-state secondary battery.

Examples of the negative electrode active material having a tin atom include Sn, SnO, and SnO₂、SnS、SnS₂And an active material containing the silicon atom and the tin atom. Further, a composite oxide with lithium oxide can be mentioned, for example, Li₂SnO₂。

The shape of the negative electrode active material is not particularly limited, and is preferably a particle shape. The average particle diameter of the negative electrode active material is preferably 0.1 to 60 μm. In order to obtain a predetermined particle size, a general pulverizer or classifier can be used. For example, a mortar, a ball mill, a sand mill, a vibration ball mill, a satellite ball mill, a planetary ball mill, a rotary air-jet type jet mill, a sieve, or the like can be preferably used. In the pulverization, if necessary, wet pulverization in the presence of an organic solvent such as water or methanol may be performed. In order to obtain a desired particle diameter, classification is preferably performed. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Both dry and wet classification can be used. The average particle diameter of the negative electrode active material particles can be measured by the same method as the method for measuring the volume average particle diameter of the positive electrode active material.

The chemical formula of the compound obtained by the above firing method can be calculated from the mass difference of the powder before and after firing by Inductively Coupled Plasma (ICP) emission spectroscopy as a measurement method and as a simple method.

The negative electrode active material may be used alone or in combination of two or more.

In the case of forming the anode active material layer, the anode active material layer has a unit area (cm)²) The mass (mg) (weight per unit area) of the negative electrode active material (b) is not particularly limited. The battery capacity can be determined as appropriate according to the designed battery capacity.

The content of the negative electrode active material in the solid electrolyte composition is not particularly limited, and is preferably 10 to 80 mass%, more preferably 20 to 80 mass% in 100 mass% of the solid content.

The surfaces of the positive electrode active material and the negative electrode active material may be coated with different metal oxides. Examples of the surface coating agent include metal oxides containing Ti, Nb, Ta, W, Zr, Al, Si, or Li. Specific examples thereof include titanic acid spinel, tantalum oxide, niobium oxide, and lithium niobate compound, and specific examples thereof include Li₄Ti₅O₁₂、Li₂Ti₂O₅、LiTaO₃、LiNbO₃、LiAlO₂、Li₂ZrO₃、Li₂WO₄、Li₂TiO₃、Li₂B₄O₇、Li₃PO₄、Li₂MoO₄、Li₃BO₃、LiBO₂、Li₂CO₃、Li₂SiO₃、SiO₂、TiO₂、ZrO₂、Al₂O₃、B₂O₃And the like.

Also, the surface of the electrode containing the positive electrode active material or the negative electrode active material may be surface-treated with sulfur or phosphorus.

The particle surface of the positive electrode active material or the negative electrode active material may be subjected to surface treatment with actinic rays or an active gas (plasma or the like) before and after the surface coating.

< other additives >

The solid electrolyte composition of the present invention may contain, as other components than the above components, a lithium salt, an ionic liquid, a thickener, a crosslinking agent (a substance which undergoes a crosslinking reaction by radical polymerization, polycondensation, or ring-opening polymerization, or the like), a polymerization initiator (a substance which generates an acid or a radical by heat or light, or the like), a defoaming agent, a leveling agent, a dehydrating agent, an antioxidant, or the like, as necessary.

In the present invention, the solid electrolyte composition of the present invention includes two modes, that is, a mode in which a crosslinking agent and a polymerization initiator are contained and a particulate binder (a polymer constituting the particulate binder) is crosslinked when forming a constituent layer described later, and a mode in which the crosslinking agent and the polymerization initiator are not contained and the particulate binder (the polymer constituting the particulate binder) is not crosslinked when forming the constituent layer (a mode in which the particulate binder does not contain a crosslinked polymer).

[ method for producing solid electrolyte composition ]

The solid electrolyte composition of the present invention can be prepared by, for example, mixing the inorganic solid electrolyte, the binder, the dispersion medium, and other components in various mixers that are generally used, and preferably as a slurry.

The mixing method is not particularly limited, and the mixing may be performed all at once or sequentially. When a particulate binder is used, the binder is generally used as a dispersion of the particulate binder, but the binder is not limited thereto. The mixing environment is not particularly limited, and examples thereof include a dry air atmosphere and an inert gas atmosphere.

[ sheet containing solid electrolyte ]

The solid electrolyte-containing sheet of the present invention is a sheet-like molded body having a layer composed of the solid electrolyte composition of the present invention and capable of forming a constituent layer of an all-solid secondary battery, and includes various modes depending on the use thereof. For example, a sheet preferably used for the solid electrolyte layer (also referred to as a solid electrolyte sheet for all-solid secondary battery), a sheet preferably used for an electrode or a laminate of an electrode and a solid electrolyte layer (an electrode sheet for all-solid secondary battery), and the like can be given.

The solid electrolyte sheet for all-solid secondary batteries of the present invention may be a sheet having a solid electrolyte layer, and may be a sheet having a solid electrolyte layer formed on a substrate or a sheet having no substrate and formed of a solid electrolyte layer. The solid electrolyte sheet for an all-solid secondary battery may have other layers in addition to the solid electrolyte layer. Examples of the other layer include a protective layer (release sheet), a current collector, and a coating layer.

The solid electrolyte sheet for an all-solid-state secondary battery of the present invention includes, for example, a sheet having a layer composed of the solid electrolyte composition of the present invention, a normal solid electrolyte layer, and, if necessary, a protective layer in this order on a substrate. The solid electrolyte layer formed from the solid electrolyte composition of the present invention contains an inorganic solid electrolyte and a binder containing a polymer having the above-mentioned specific constituent, and is excellent in adhesion. The solid electrolyte layer does not generally contain an active material, as in the case of the solid electrolyte layer in the all-solid secondary battery described later. The solid electrolyte sheet for an all-solid secondary battery can be suitably used as a material constituting a solid electrolyte layer of the all-solid secondary battery.

The substrate is not particularly limited as long as it can support the solid electrolyte layer, and examples thereof include a material described below for the current collector, and a sheet-like body (plate-like body) such as an organic material and an inorganic material. Examples of the organic material include various polymers, and specific examples thereof include polyethylene terephthalate, polypropylene, polyethylene, and cellulose. Examples of the inorganic material include glass and ceramic.

The electrode sheet for an all-solid-state secondary battery of the present invention (also simply referred to as "the electrode sheet of the present invention") may be a sheet in which an active material layer is formed on a substrate (current collector), or may be a sheet in which an active material layer is formed without a substrate, as long as the electrode sheet has an active material layer. The electrode sheet is generally a sheet having a current collector and an active material layer, but may be a sheet having a current collector, an active material layer, and a solid electrolyte layer in this order, or a sheet having a current collector, an active material layer, a solid electrolyte layer, and an active material layer in this order. The electrode sheet of the present invention may have the other layers described above. The thickness of each layer constituting the electrode sheet of the present invention is the same as that of each layer described in the all-solid-state secondary battery described later.

The active material layer of the electrode sheet is preferably formed of the solid electrolyte composition (electrode composition) of the present invention. The electrode sheet can be suitably used as a material constituting an active material layer (negative electrode or positive electrode) of an all-solid-state secondary battery.

[ method for producing solid electrolyte-containing sheet ]

The solid electrolyte-containing sheet of the present invention can be manufactured using the solid electrolyte composition of the present invention. For example, there is a method of preparing the solid electrolyte composition of the present invention as described above, forming a film (coating and drying) of the obtained solid electrolyte composition on a substrate (or via another layer), and forming a solid electrolyte layer (coating and drying layer) on the substrate. This makes it possible to produce a solid electrolyte-containing sheet having a substrate (current collector) and a coating dry layer as needed. Here, the coating dry layer refers to a layer formed by coating the solid electrolyte composition of the present invention and drying the dispersion medium (i.e., a layer formed using the solid electrolyte composition of the present invention and composed of a composition in which the dispersion medium is removed from the solid electrolyte composition of the present invention). The active material layer and the coating dry layer may be left in the dispersion medium as long as the effects of the present invention are not impaired, and the residual amount may be 3 mass% or less in each layer, for example.

In the above-described production method, the solid electrolyte composition of the present invention is preferably used as a slurry, and the solid electrolyte composition of the present invention can be slurried by a known method as desired. The steps of applying and drying the solid electrolyte composition of the present invention will be described in the following method for manufacturing an all-solid-state secondary battery.

In the method for producing a solid electrolyte-containing sheet of the present invention, the dried coating layer obtained in the above-described manner can also be pressurized. The pressurizing conditions and the like will be described in a method for manufacturing an all-solid-state secondary battery described later.

In the method for producing a solid electrolyte-containing sheet of the present invention, the substrate, the protective layer (particularly, a release sheet), and the like can be peeled off.

[ all-solid-state secondary battery ]

The all-solid-state secondary battery of the present invention has a positive electrode active material layer, a negative electrode active material layer facing 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 positive electrode active material layer is formed on a positive electrode current collector as needed, and constitutes a positive electrode. The negative electrode active material layer is formed on a negative electrode current collector as needed, and constitutes a negative electrode.

At least one of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer is preferably formed of the solid electrolyte composition of the present invention, and all of the layers are formed of the solid electrolyte composition of the present invention. The active material layer or the solid electrolyte layer formed of the solid electrolyte composition of the present invention preferably contains the same kinds of components and content ratios thereof as in the solid components of the solid electrolyte composition of the present invention. In addition, when the active material layer or the solid electrolyte layer is not formed from the solid electrolyte composition of the present invention, a known material can be used.

The respective thicknesses of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer are not particularly limited. In view of the size of a general all-solid secondary battery, the thickness of each layer is preferably 10 to 1,000 μm, and more preferably 20 μm or more and 500 μm or less. 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 more preferably 50 μm or more and less than 500 μm.

The positive electrode active material layer and the negative electrode active material layer may each include a current collector on the opposite side of the solid electrolyte layer.

(Positive electrode active material layer, solid electrolyte layer, negative electrode active material layer)

In the all-solid-state secondary battery of the present invention, as described above, the solid electrolyte composition or the active material layer can be formed of the solid electrolyte composition of the present invention or the above-described solid electrolyte-containing sheet. The solid electrolyte layer and the active material layer to be formed are preferably the same as those in the solid electrolyte composition or the solid electrolyte-containing sheet, unless otherwise specified, in terms of the respective components and contents thereof contained therein.

The thickness of each of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer is not particularly limited. In view of the size of a general all-solid secondary battery, the thickness of each layer is preferably 10 to 1,000 μm, and more preferably 20 μm or more and 500 μm or less. In the all-solid-state secondary battery of the present invention, the thickness of at least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is more preferably 50 μm or more and less than 500 μm.

(case)

The all-solid-state secondary battery of the present invention can be used as an all-solid-state secondary battery in the state of the above-described structure according to the application, and is preferably used by being further enclosed in an appropriate case in order to be a form of a dry battery. The case may be a metallic case or a resin (plastic) case. When a metallic case is used, for example, aluminum alloy and stainless steel cases can be used. Preferably, the metallic case is divided into a positive-electrode-side case and a negative-electrode-side case, and is electrically connected to the positive-electrode current collector and the negative-electrode current collector, respectively. Preferably, the case on the positive electrode side and the case on the negative electrode side are joined and integrated via a short-circuit prevention gasket.

Hereinafter, an all-solid secondary battery according to a preferred embodiment of the present invention will be described with reference to fig. 1, but the present invention is not limited thereto.

Fig. 1 is a cross-sectional view schematically showing an all-solid secondary battery (lithium-ion secondary battery) according to a preferred embodiment of the present invention. The all-solid-state secondary battery 10 of the present embodiment includes, in order from the negative electrode side, 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. The layers are in contact with each other, respectively, to form a laminated structure. With such a configuration, electrons (e) are supplied to the negative electrode side during charging^-) And accumulating lithium ions (Li) therein⁺). On the other hand, lithium ions (Li) accumulated in the negative electrode during discharge⁺) Returning to the positive electrode side, electrons are supplied to the working site 6. In the illustrated example, a bulb is used for the working site 6, and the bulb is turned on by discharge.

The solid electrolyte composition of the present invention can be preferably used as a molding material for the solid electrolyte layer, the negative electrode active material layer, or the positive electrode active material layer. The solid electrolyte-containing sheet of the present invention is suitable as a solid electrolyte layer/negative electrode active material layer or a positive electrode active material layer.

In this specification, a positive electrode active material layer (hereinafter, also referred to as a positive electrode layer) and a negative electrode active material layer (hereinafter, also referred to as a negative electrode layer) are collectively referred to as an electrode layer or an active material layer.

When the all-solid-state secondary battery having the layer structure shown in fig. 1 is placed in a 2032-type button cell, the all-solid-state secondary battery is sometimes referred to as a laminate for all-solid-state secondary batteries, and a battery produced by placing the laminate for all-solid-state secondary batteries in a 2032-type button cell is sometimes referred to as an all-solid-state secondary battery.

In the all-solid-state secondary battery 10, either the solid electrolyte layer or the active material layer is formed using the solid electrolyte composition of the present invention or the solid electrolyte-containing sheet described above. In a preferred embodiment, all layers are formed using the solid electrolyte composition of the present invention or the solid electrolyte-containing sheet, and in another preferred embodiment, the solid electrolyte layer and the positive electrode active material layer are formed using the solid electrolyte composition of the present invention or the solid electrolyte-containing sheet. The negative electrode active material layer can be formed using a layer composed of a metal or an alloy as a negative electrode active material, a layer composed of a carbonaceous material as a negative electrode active material, or the like, in addition to the solid electrolyte composition of the present invention or the above-mentioned electrode sheet, and can be formed by depositing a metal belonging to group 1 or group 2 of the periodic table on a negative electrode current collector or the like at the time of charging.

The respective components contained in the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 may be the same type or different types.

The positive electrode current collector 5 and the negative electrode current collector 1 are preferably electron conductors.

In the present invention, either one or both of the positive electrode current collector and the negative electrode current collector may be simply referred to as a current collector.

As a material for forming the positive electrode current collector, in addition to aluminum, an aluminum alloy, stainless steel, nickel, titanium, and the like, a material (a material forming a thin film) in which carbon, nickel, titanium, or silver is treated on the surface of aluminum or stainless steel is preferable, and among these, aluminum and an aluminum alloy are more preferable.

As a material forming the negative electrode current collector, in addition to aluminum, copper, a copper alloy, stainless steel, nickel, titanium, and the like, a material obtained by treating the surface of aluminum, copper, a copper alloy, or stainless steel with carbon, nickel, titanium, or silver is preferable, and aluminum, copper, a copper alloy, and stainless steel are more preferable.

The shape of the current collector is generally a diaphragm shape, but a mesh, a perforated body, a lath body, a porous body, a foam, a molded body of a fiber group, or the like can also be used.

The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm. Further, it is also preferable to provide irregularities on the surface of the current collector by surface treatment.

In the present invention, functional layers or members and the like may be appropriately inserted or disposed between or outside the respective 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. Each layer may be a single layer or a plurality of layers.

[ method for producing all-solid-state Secondary Battery ]

The all-solid-state secondary battery of the present invention is not particularly limited, and can be produced by (including) the method for producing the solid electrolyte composition of the present invention. The solid electrolyte composition of the present invention can be used for production, taking into consideration the raw materials used. Specifically, the all-solid secondary battery can be manufactured by: the solid electrolyte composition of the present invention is prepared as described above, and the obtained solid electrolyte composition and the like are used to form the solid electrolyte layer and/or the active material layer of the all-solid secondary battery. This makes it possible to manufacture an all-solid-state secondary battery having a high battery capacity. The preparation method of the solid electrolyte composition of the present invention is as described above, and thus omitted.

The all-solid-state secondary battery of the present invention can be produced by a method including (via) a step of applying the solid electrolyte composition of the present invention to a substrate (for example, a metal foil serving as a current collector) to form a coating film (film formation).

For example, a positive electrode sheet for an all-solid-state secondary battery is produced by applying the solid electrolyte composition (electrode composition) of the present invention as a positive electrode composition to a metal foil serving as a positive electrode current collector to form a positive electrode active material layer. Next, a solid electrolyte layer is formed by coating the solid electrolyte composition of the present invention for forming a solid electrolyte layer on the positive electrode active material layer. Further, the solid electrolyte composition of the present invention (composition for an electrode) is applied as a composition for a negative electrode on the solid electrolyte layer to form a negative electrode active material layer. By stacking an anode current collector (metal foil) on the anode active material layer, an all-solid-state secondary battery having a structure in which a solid electrolyte layer is sandwiched between a cathode active material layer and an anode active material layer can be obtained. If necessary, the battery can be sealed in a case to obtain a desired all-solid-state secondary battery.

In addition, contrary to the method of forming each layer, an all-solid-state secondary battery can also be manufactured 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 and stacking the positive electrode current collector thereon.

Other methods include the following methods. That is, the positive electrode sheet for all-solid-state secondary battery was produced as described above. Then, the solid electrolyte composition of the present invention is applied onto a metal foil as a negative electrode current collector to form a negative electrode active material layer as a negative electrode composition, thereby producing a negative electrode sheet for an all-solid secondary battery. Next, the solid electrolyte composition of the present invention is applied to the active material layer of any of these sheets as described above to form a solid electrolyte layer. The other of the positive electrode sheet for an all-solid secondary battery and the negative electrode sheet for an all-solid secondary battery is laminated on the solid electrolyte layer so that the solid electrolyte layer is in contact with the active material layer. In this manner, an all-solid-state secondary battery can be manufactured.

Further, as another method, the following method can be mentioned. That is, the positive electrode sheet for the all-solid-state secondary battery and the negative electrode sheet for the all-solid-state secondary battery were produced as described above. In addition, a solid electrolyte composition is applied to a substrate to produce a solid electrolyte sheet for an all-solid-state secondary battery, which is composed of a solid electrolyte layer. The positive electrode sheet for all-solid secondary batteries and the negative electrode sheet for all-solid secondary batteries are stacked so as to sandwich the solid electrolyte layer peeled from the base material. In this manner, an all-solid-state secondary battery can be manufactured.

The above-described manufacturing methods are all methods for forming the solid electrolyte layer, the negative electrode active material layer, and the positive electrode active material layer using the solid electrolyte composition of the present invention, but in the manufacturing method of the all-solid-state secondary battery of the present invention, at least one of the solid electrolyte layer, the negative electrode active material layer, and the positive electrode active material layer is formed using the solid electrolyte composition of the present invention. When a solid electrolyte layer is formed using a composition other than the solid electrolyte composition of the present invention, examples of the material include a solid electrolyte composition generally used, a composition for a negative electrode known in the art for forming a negative electrode active material layer, a metal or alloy (metal layer) as a negative electrode active material, a carbonaceous material (carbonaceous material layer) as a negative electrode active material, and the like.

< formation of layers (film formation) >

The method of applying the composition for producing the all-solid secondary battery is not particularly limited and can be appropriately selected. Examples thereof include coating (preferably wet coating), spray coating, spin coating, dip coating, slit coating, stripe coating, and bar coating.

In this case, the composition may be separately coated and then dried, or may be coated in multiple layers and then dried. The drying temperature is not particularly limited. The lower limit is preferably 30 ℃ or higher, more preferably 60 ℃ or higher, and still more preferably 80 ℃ or higher. The upper limit is preferably 300 ℃ or lower, more preferably 250 ℃ or lower, and still more preferably 200 ℃ or lower. By heating in such a temperature range, the dispersion medium can be removed to obtain a solid state (coating dry layer). Further, it is preferable that the temperature is not excessively high, and the components of the all-solid-state secondary battery are not damaged. Thereby, in the all-solid-state secondary battery, excellent overall performance is exhibited and good adhesion can be obtained.

As described above, when the solid electrolyte composition of the present invention is applied and dried, the solid particles are firmly bonded to each other, and a dried-applied layer in which the interface resistance between the solid particles is small and the voids are small as required and which is dense can be formed.

The applied composition or each layer after the all-solid secondary battery is manufactured or the all-solid secondary battery is preferably pressurized. Further, it is also preferable to apply pressure in a state where the layers are laminated. Examples of the pressurizing method include a hydraulic cylinder press. The pressurizing force is not particularly limited, but is preferably in the range of 50 to 1500 MPa.

Also, the coated composition may be heated while being pressurized. The heating temperature is not particularly limited, but is generally in the range of 30 to 300 ℃. It is also possible to perform pressing at a temperature higher than the glass transition temperature of the inorganic solid electrolyte.

The pressurization may be performed in a state where the coating solvent or the dispersion medium is dried in advance, or may be performed in a state where the coating solvent or the dispersion medium remains.

The respective compositions may be applied simultaneously, or may be applied, dried, and pressed simultaneously and/or stepwise. The lamination may be performed by transfer after coating to the respective substrates.

The atmosphere under pressure is not particularly limited, and any atmosphere of atmospheric pressure, dry air (dew point-20 ℃ C. or lower), inert gas (e.g., argon gas, helium gas, nitrogen gas), or the like can be used. The inorganic solid electrolyte reacts with moisture, and therefore the atmosphere gas at the time of pressurization is preferably under dry air or in an inert gas.

The pressing time may be a short time (for example, within several hours) to apply a high pressure, or may be a long time (for example, 1 day or more) to apply an intermediate pressure. In addition to the solid electrolyte-containing sheet, for example, in the case of an all-solid secondary battery, a restraining tool (screw fastening pressure or the like) of the all-solid secondary battery can be used to continuously apply moderate pressure.

The pressing pressure may be uniform or different with respect to the pressed portion such as the sheet surface.

The pressing pressure can be changed according to the area and the film thickness of the pressure receiving portion. Further, the same portion can be changed in stages with different pressures.

The stamping surface may be smooth or rough.

< initialization >

The all-solid secondary battery manufactured as described above is preferably initialized after manufacture or before use. The initialization is not particularly limited, and for example, the initial charge and discharge can be performed in a state where the pressing pressure is increased, and then the pressure can be released until the general use pressure of the all-solid secondary battery is reached.

[ uses of all-solid-state Secondary batteries ]

The all-solid-state secondary battery of the present invention can be applied to various uses. The application method is not particularly limited, and examples of the electronic device include a notebook computer, a pen-input computer, a mobile computer, an electronic book reader, a mobile phone, a wireless telephone handset, a pager, a handheld terminal, a portable facsimile machine, a portable copier, a portable printer, a stereo headphone, a camcorder, a liquid crystal television, a portable vacuum cleaner, a portable CD, a compact disc, an electric shaver, a transceiver, an electronic organizer, a calculator, a portable recorder, a radio, a backup power source, and a memory card. Examples of other consumer goods include automobiles (e.g., electric cars), electric cars, motors, lighting fixtures, toys, game machines, load regulators, clocks, flashlights, cameras, and medical devices (e.g., cardiac pacemakers, hearing aids, and shoulder massagers). Moreover, it can be used as various military supplies and aviation supplies. And, it can also be combined with a solar cell.

Examples

The present invention will be described in further detail below with reference to examples. The present invention is not limited to this explanation. In the following examples, "part" and "%" representing the composition are based on mass unless otherwise specified.

< Synthesis of Polymer (preparation of Polymer Dispersion or solution) >)

(Synthesis of Polymer B-1)

To a 500mL three-necked flask, 14.51g of polyethylene glycol (PEG200 (trade name), number average molecular weight 200, manufactured by FUJIFILM Wako Pure Chemical Corporation) and 26.28g of NISSO-PB GI-1000 (trade name, NIPPON SODA CO., manufactured by LTD.) were charged and dissolved in 264g of THF (tetrahydrofuran). To the solution was added 24.78g of diphenylmethane diisocyanate (manufactured by FUJIFILM Wako Pure Chemical Corporation) and stirred at 60 ℃ to dissolve it uniformly.

To the obtained solution, 120mg of NEOSTANN U-600 (trade name, NITTO KASEI co., ltd., manufactured) was added, and stirred at 60 ℃ for 5 hours. To the solution was added 0.53g of 4-amino-1-butanol (manufactured by FUJIFILM Wako Pure Chemical Corporation), and stirred at 60 ℃ for 30 minutes to obtain a viscous polymer solution. To the polymer solution was added 1.9g of methanol, and the polymer end was sealed to stop the polymerization reaction, thereby obtaining a 20 mass% THF solution of polymer B-1 (polymer solution).

Subsequently, 720g of heptane was added dropwise over 1 hour while stirring the polymer solution obtained in the above at 350rpm, to obtain an emulsion of polymer B-1. The emulsion was heated at 85 ℃ for 120 minutes while flowing nitrogen. To the residue obtained, 150g of heptane was added, and further heated at 85 ℃ for 60 minutes. This operation was repeated 4 times to remove THF. Thus, a 10 mass% heptane dispersion of an adhesive consisting of polymer B-1 was obtained.

(Synthesis of polymers B-2 to B-11)

Polymers B-2 to B-11 (polymer dispersions or solutions) were synthesized (prepared) in the same manner as the synthesis of polymer B-1 except that in the synthesis of polymer B-1, compounds for deriving or forming the constituent components described in table 1 below were used in amounts such that the contents of the compounds for deriving the constituent components are the same as those used in the tables.

(Synthesis of Polymer B-12)

In a 500mL flask equipped with a thermometer, a stirrer, and a nitrogen gas inlet, 27.3g of terephthalic acid dichloride (manufactured by FUJIFILM Wako Pure Chemical Corporation) was dissolved in 200mL of Tetrahydrofuran (THF), and cooled to 5 ℃. To this was added 30.3g of triethylamine, and 21.6g of dodecyldiamine (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 1.1g of 3-amino-1 propanol (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added in 30 minute portions. After stirring at room temperature for 3 hours, reprecipitation was performed in methanol and redissolved in THF, thereby obtaining a THF solution of binder B-12.

(Synthesis of polymers B-13 to B-21)

Polymers B-13 to B-21 (polymer dispersions) were synthesized (prepared) in the same manner as the synthesis of polymer B-1 except that in the synthesis of polymer B-1, compounds for deriving or forming the constituent components described in table 1 below were used in amounts such that the contents of the compounds for deriving the constituent components were the same.

(Synthesis of Polymer BC-1)

2.5g of 4,4' -diphenylmethane diisocyanate (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 17.6g of JEFFAMINE D-2000 (trade name, manufactured by Huntsman Corporation; polyoxypropylene diamine, average molecular weight 2,000) were charged into a 200mL flask and dissolved in 52g of Methyl Ethyl Ketone (MEK). After heating to 60 ℃ and stirring for 30 minutes, 51mg of Neostann U-600(NITTO KASEI CO., LTD.; tris (2-ethylhexanoate) bismuth) was added, and the mixture was heated and stirred at 60 ℃ for 5 hours. 1.7g of butylamine was added thereto, and the mixture was further heated and stirred at 60 ℃ for 1 hour to obtain a 30 mass% polymer solution of an adhesive composed of the polymer BC-1.

(Synthesis of Polymer BC-2)

A500 mL three-necked flask was charged with 20mL of methyl ethyl ketone, and heated at 75 ℃ under a nitrogen stream. On the other hand, 70g of dodecyl methacrylate (12 carbon atoms in the alkyl moiety, manufactured by FUJIFILM Wako Pure Chemical Corporation) and 110g of methyl ethyl ketone were charged into a 500mL measuring cylinder and sufficiently stirred. 2.9g of thioglycerol (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 3.2g of a radical polymerization initiator V-601 (manufactured by FUJIFILM Wako Pure Chemical Corporation) as a chain transfer agent were added thereto, and further sufficiently stirred. The obtained monomer solution was added dropwise to a 500mL three-necked flask over 2 hours, and radical polymerization was started. After the completion of the dropwise addition, the mixture was further heated and stirred at 75 ℃ for 6 hours. The obtained polymerization solution was concentrated under reduced pressure, and after methyl ethyl ketone was distilled off, the solution was dissolved in heptane to obtain a terminal diol-modified poly (dodecyl methacrylate) (DOPMD) [ number of carbon atoms at the alkyl moiety 12; 292g of a 25% by mass heptane solution of the lipophilic polymer of a terminal diol. The mass average molecular weight of the obtained polymer was 3200.

260g of a 25 mass% heptane solution of terminal diol-modified poly (dodecyl methacrylate) (DOPMD; diol compound) was charged into a1 liter (L) three-necked flask and diluted with 110g of heptane. 11.1g of isophorone diisocyanate (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 0.1g of NEOSTANN U-600 (trade name, NITTO KASEI CO., manufactured by LTD., catalyst) were added thereto, and stirred with heating at 75 ℃ for 5 hours. Then, 125g of a diluted solution of 0.4g of isophoronediamine (amine compound) in heptane was added dropwise over 1 hour. The polymer solution changed from transparent to a solution having a yellowish fluorescent color 10 minutes after the start of dropping. This revealed that a urea colloid was formed. The reaction solution was cooled to room temperature, and 506g of a 15 mass% heptane solution of polyurea colloidal particles (Aa-1) [ particles having a polyurea structure ] was obtained.

In the polyurea colloidal particles (Aa-1), the dodecyl group contained in the component derived from the terminal diol-modified poly (dodecyl methacrylate) is a moiety solvated with heptane (a hydrocarbon solvent), and the polyurea structure is a moiety not solvated with heptane. The mass average molecular weight of polyurea of the polyurea colloidal particles (Aa-1) was 9600.

A50 mL sample bottle was charged with 2.6g of dicyclohexylmethane diisocyanate (Tokyo Chemical Industry Co., Ltd.), 0.42g of 1, 4-butanediol (FUJIFILM Wako Pure Chemical Corporation), 0.28g of 2, 2-bis (hydroxymethyl) butyric acid (Tokyo Chemical Industry Co., Ltd.), and 2.9g of KURARAY POLYOL P-1020 (KURAY CO., LTD.). 15.7g of a 15 mass% heptane solution of polyurea colloidal particles (Aa-1) was added thereto, and the mixture was dispersed with a homogenizer for 30 minutes while being heated at 50 ℃. During this time, the mixed solution was atomized to obtain a pale orange slurry. The obtained slurry was quickly charged into a 100mL three-necked flask previously stirred at 80 ℃ and 400rpm, 0.1g of NEOSTANN U-600 (trade name, NITTO KASEI CO., LTD., Ltd.) was added, and the mixture was heated and stirred at 80 ℃ for 3 hours. The slurry was white and opaque. From this, it is presumed that polyurethane particles were formed. The white, opaque slurry was cooled to obtain a 40% by mass heptane dispersion of an adhesive consisting of polymer BC-2.

(Synthesis of Polymer BC-3)

Polymer BC-3 (polymer dispersion) was synthesized (prepared) in the same manner as the synthesis of Polymer B-1 except that the compounds for deriving or forming the components shown in Table 1 below were used in the same amounts as the amounts used for deriving the components shown in the same tables in the synthesis of Polymer B-1.

The structure of the synthesized polymer is shown below.

[ chemical formula 18]

[ chemical formula 19]

The average particle diameter of the particulate polymer was measured for each of the obtained polymer dispersions by the above-mentioned method. The results are shown in table 1.

The mass average molecular weight of the polymer or the like was measured by the above-described method.

The dispersed state of the polymer (the state of formation of the particulate polymer) in each of the obtained particulate polymer dispersions was visually evaluated and is shown in the column of "shape" in table 1. The state in which the polymer is dispersed in the dispersion medium to form a particulate polymer is referred to as "particles". On the other hand, a state in which the polymer is precipitated without being dispersed in the dispersion medium is referred to as "precipitation", and a state in which the polymer is dissolved without forming a particulate polymer and becomes a solution is referred to as "solution".

The urea value shown in table 1 below was calculated as follows.

The urea value can be generally calculated from the amount (mmol) of the amino group-containing compound used at the time of polymer synthesis and (the number of amino groups of the amino group-containing compound (the number of amino groups that one molecule of the amino group-containing compound has)/the total mass (g) of the amino group-containing compound). Also, NMR of the polymer can be measured, and the urea group content can be calculated from the integral ratio of the peaks of urea groups. In this example, the urea value used for the amino group-containing compound used in the synthesis almost coincides with the urea value obtained by NMR of the polymer.

< notes on the Table >

Constituent M1: a constituent component represented by the formula (I-1) or (I-2)

Constituent M2: a constituent component represented by the formula (I-3B)

Constituent M3: a constituent component represented by the formula (I-3C)

Constituent M4: a constituent component represented by the formula (H-1)

Constituents M5 and M6: a constituent component represented by the formula (I-3A) or (I-4)

The constituent components of the polymers BC-1 to BC-3 are described in the column of the constituent components.

MDI: diphenylmethane diisocyanate (manufactured by FUJIFILM Wako Pure Chemical Corporation)

PEG 200: polyethylene glycol (number average molecular weight: 200 manufactured by FUJIFILM Wako Pure Chemical Corporation)

GI 1000: NISSO-PB GI-1000 (trade name, NIPPON SODA CO., LTD. manufacture)

4A 1B: 4-amino-1-butanol (manufactured by FUJIFILM Wako Pure Chemical Corporation)

DMBA: 2, 2-bis (hydroxymethyl) butanoic acid (Tokyo Chemical Industry Co., Ltd.; manufactured by Ltd.)

3A 1P: 3-amino-1-propanol (manufactured by FUJIFILM Wako Pure Chemical Corporation)

4 ACE: 4-Aminocyclohexane Ethanol (manufactured by Tokyo Chemical Industry Co., Ltd.)

Bis-A: 2, 2-bis (4-hydroxyphenyl) propane (manufactured by FUJIFILM Wako Pure Chemical Corporation)

G3450J: duranol G3450J (trade name, number average molecular weight: 800 manufactured by Asahi Kasei Corporation)

PTMG 250: polytetramethylene glycol (number average molecular weight: 250 SIGMA-Aldrich Co., Ltd.)

4 AP: 2- (4-aminophenyl) ethanol (manufactured by Tokyo Chemical Industry Co., Ltd.)

And (3) DEGA: diglycolamine (Tokyo Chemical Industry Co., Ltd.; manufactured by Ltd.)

G1000: NISSO-PB G-1000 (trade name, NIPPON SODA CO., LTD. manufactured)

D-2000: (trade name, polyoxypropylenediamine, number average molecular weight 2,000, manufactured by Huntsman Corporation)

BA: butyl amine

H12 MDI: dicyclohexylmethane diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.)

BD: 1, 4-butanediol (manufactured by FUJIFILM Wako Pure Chemical Corporation)

P-1020: KURARAY POLYOL P-1020 (trade name, KURAY CO., LTD, manufactured by LTD)

IPDI: isophorone diisocyanate (manufactured by FUJIFILM Wako Pure Chemical Corporation)

IPDA: isophoronediamine (manufactured by FUJIFILM Wako Pure Chemical Corporation)

TPDC: terephthalic acid dichloride (manufactured by FUJIFILM Wako Pure Chemical Corporation)

DDA: dodecanediamine (manufactured by FUJIFILM Wako Pure Chemical Corporation)

BDA: 1, 4-butanediamine (manufactured by FUJIFILM Wako Pure Chemical Corporation)

DOPMD: the above-mentioned terminal diol-modified poly (dodecyl methacrylate)

A dispersion of polymer BC-4 was prepared in the same manner as polymer B-2, except that 4A1B (4-amino-1-butanol) was not used in the preparation of the dispersion of polymer B-2.

The dispersion of polymer B-2 was placed in a glass petri dish and dried at 100 ℃ for 3 hours to obtain a dried film having a film thickness of 80 μm. The obtained film was cut into a width of 10mm and a length of 40mm, and set on a dynamometer (manufactured by IMADA) so that the chuck pitch became 30 mm. Pulling at a speed of 10mm/min, measuring the amount of displacement and stress, calculating the modulus of elasticity from the initial slope, and calculating the elongation at break from the amount of displacement at break. Similarly, a film was prepared from a dispersion of the polymer BC-4, and the elastic modulus and elongation at break were calculated.

The elastic modulus and elongation at break of the film made of the polymer B-2 were 1.6 times and 1.5 times as high as those of the film made of the polymer BC-4.

(the elastic modulus of the film made of the polymer B-2/the elastic modulus of the film made of the polymer BC-4 was 1.6, and the elongation at break of the film made of the polymer B-2/the elongation at break of the film made of the polymer BC-4 was 1.5.)

< Synthesis of sulfide-based inorganic solid electrolyte >

As sulfide-based inorganic solid electrolytes, Li-P-S-based glasses have been synthesized by non-patent documents of 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.minia, chem.lett., (2001), pp 872-873.

Specifically, 2.42g of lithium sulfide (Li) was weighed in a glove box under an argon atmosphere (dew point-70 ℃ C.)₂Manufactured by Aldrich. Inc, purity > 99.98%) and 3.90g of phosphorus pentasulfide (P)₂S₅Inc, purity > 99%) and put into a mortar. Li₂S and P₂S₅Given as Li in terms of molar ratio₂S：P₂S₅75: 25. on the Menow milk bowl, the Menow milk rod was used for mixing for 5 minutes.

Into a 45mL vessel (manufactured by Fritsch co., Ltd) made of zirconia, 66g of zirconia beads having a diameter of 5mm were put, and the total amount of the mixture was put, and the vessel was sealed under an argon atmosphere. 6.20g of a sulfide-based inorganic solid electrolyte (Li-P-S-based glass, LPS) was obtained as a yellow powder by placing the container in a planetary ball mill P-7 (trade name) manufactured by Fritsch Co., Ltd and mechanically milling the container at 25 ℃ and 510rpm for 20 hours. The volume average particle diameter was 15 μm.

[ example 1]

The solid electrolyte composition and the solid electrolyte-containing sheet were produced, respectively, and the following characteristics were evaluated for the solid electrolyte composition and the solid electrolyte-containing sheet. The results are shown in tables 2 and 3.

< preparation of solid electrolyte composition >

To a 45mL vessel (manufactured by Fritsch co., Ltd) made of zirconia, 180 zirconia beads having a diameter of 5mm were put, and 4.85g of the synthesized LPS described above, 16.0g of a dispersion or solution (solid content mass: 0.15g) of the polymer shown in table 2, and the dispersion medium shown in table 2 were put. Thereafter, the vessel was set in a Fritsch Co., Ltd, planetary ball mill P-7 (trade name), and mixed at a rotation speed of 150rpm at a temperature of 25 ℃ for 10 minutes to prepare solid electrolyte compositions C-1 to C-22 and BC-1 and BC-3, respectively.

Production of sheet containing solid electrolyte

Each of the solid electrolyte compositions C-1 to C-22 and BC-1 to BC-3 obtained above was coated on an aluminum foil having a thickness of 20 μm using an applicator (trade name: SA-201, bake-type applicator, manufactured by ltd.), heated at 80 ℃ for 2 hours, and dried. Then, the dried solid electrolyte composition was heated and pressurized at a temperature of 120 ℃ and a pressure of 600Mpa for 10 seconds using a hot press, thereby producing solid electrolyte-containing sheets S-1 to S-22 and BS-1 and BS-3, respectively. The film thickness of the solid electrolyte layer was 50 μm.

< evaluation 1: evaluation of dispersibility >

The solid electrolyte composition was added to a glass test tube having a diameter of 10mm and a height of 15cm until the height reached 10cm, and after standing at 25 ℃ for 2 hours, the height of the separated supernatant was visually confirmed and measured. The ratio of the height of the supernatant to the total amount of the solid electrolyte composition (height 10cm) was determined: height of supernatant/height of total amount. The dispersibility (dispersion stability) of the solid electrolyte composition was evaluated by which evaluation level the ratio was included below. When the above ratio is calculated, the total amount means the total amount (10cm) of the solid electrolyte composition charged into the glass test tube, and the height of the supernatant means the amount (cm) of the supernatant (subjected to solid-liquid separation) generated by precipitation of the solid components of the solid electrolyte composition.

In this test, the smaller the above ratio, the more excellent the dispersibility was exhibited, and the evaluation scale of "4" or more was an acceptable level.

Evaluation scale-

8: the height of the supernatant/the height of the total amount of the supernatant is less than 0.1

7: the height of the supernatant/total amount is not less than 0.1 and less than 0.2

6: the height of the supernatant/total amount is not less than 0.2 and less than 0.3

5: the height of the supernatant/total amount is not less than 0.3 and less than 0.4

4: the height of the supernatant/total amount is not less than 0.4 and less than 0.5

3: the height of the supernatant/total amount is not less than 0.5 and less than 0.7

2: the height of the supernatant/total amount is not less than 0.7 and less than 0.9

1: height of 0.9. ltoreq. of supernatant/height of total amount

< evaluation 2: evaluation of adhesion >

The solid electrolyte-containing sheets were wound around rods having different diameters, and the presence or absence of a defect, a crack or a crack of the solid electrolyte layer and the presence or absence of peeling from the aluminum foil (current collector) of the solid electrolyte layer were confirmed. The adhesiveness was evaluated according to which of the following evaluation grades the minimum diameter of the wound rod without occurrence of abnormality such as these defects is included.

In the present invention, the smaller the minimum diameter of the rod, the stronger the adhesiveness, and the evaluation rating of "4" or more was acceptable.

Evaluation of the adhesion-

8: minimum diameter < 2mm

7: the minimum diameter is more than or equal to 2mm and less than 4mm

6: the minimum diameter is more than or equal to 4mm and less than 6mm

5: the minimum diameter is less than or equal to 6mm and less than 10mm

4: the minimum diameter is less than or equal to 10mm and less than 14mm

3: the minimum diameter is more than or equal to 14mm and less than 20mm

2: the minimum diameter is more than or equal to 20mm and less than 32mm

1: minimum diameter of 32mm or less

< evaluation 3: measurement of ion conductivity

The solid electrolyte-containing sheet obtained in the above was cut into a disk shape having a diameter of 14.5mm, and the solid electrolyte-containing sheet was put into a 2032-type button-type battery can 11 shown in fig. 2. Specifically, an aluminum foil (not shown in fig. 2) cut into a disk shape having a diameter of 15mm was brought into contact with the solid electrolyte layer of the solid electrolyte-containing sheet to form an ion conductivity measurement sample 12 (a laminate composed of an aluminum-solid electrolyte layer-aluminum), and a spacer and a gasket (both not shown in fig. 2) were inserted into the stainless steel-made 2032-type button cell case 11. Sample 13 for ion conductivity measurement was prepared by crimping 2032 type button cell case 11.

The ion conductivity was measured using the obtained sample for ion conductivity measurement 13. Specifically, in a thermostatic bath at 25 ℃, 1255B FREQUENCY RESPONSE ANALYZER (trade name) AC impedance manufactured by SOLARRON corporation was measured to have a voltage amplitude of 5mV and a FREQUENCY of 1MHz to 1 Hz. The resistance in the film thickness direction of the sample is thus obtained, and is calculated by the following formula (1).

Ionic conductivity (mS/cm) ═

1000 times sample film thickness (cm)/{ resistance (Ω) × sample area (cm)²) … … type (1)

In equation (1), the sample film thickness and the sample area are values obtained by measuring and subtracting the thickness of the aluminum foil (i.e., the film thickness and the area of the solid electrolyte layer) before the laminate 12 is placed in the 2032 type button cell case 16.

It is determined whether the obtained ion conductivity is included in which evaluation level described below.

In the ion conductivity in this experiment, the evaluation level "4" or more was acceptable.

Evaluation scale-

8: ionic conductivity not more than 0.5mS/cm

7: ionic conductivity not less than 0.4mS/cm and less than 0.5mS/cm

6: ionic conductivity not less than 0.3mS/cm and less than 0.4mS/cm

5: ionic conductivity not less than 0.2mS/cm and less than 0.3mS/cm

4: ionic conductivity not less than 0.1mS/cm and less than 0.2mS/cm

3: ionic conductivity not less than 0.05mS/cm and less than 0.1mS/cm

2: ionic conductivity not less than 0.01mS/cm and less than 0.05mS/cm

1: ionic conductivity < 0.01mS/cm

[ Table 2]

As is clear from table 2, the dispersibility of the solid electrolyte composition that does not satisfy the specification of the present invention was evaluated as failing. The solid electrolyte-containing sheet produced from the solid electrolyte composition that does not satisfy the requirements of the present invention was determined to be defective in the evaluation of adhesion and ion conductivity.

On the other hand, the dispersibility of the solid electrolyte composition of the present invention was evaluated as acceptable, and the adhesiveness and ion conductivity of the solid electrolyte-containing sheet produced from the solid electrolyte composition of the present invention were evaluated as acceptable. Further, from comparison of the solid electrolyte compositions C-8 and C-21 and comparison of the solid electrolyte-containing sheets S-8 and S-21, it is understood that the evaluation of dispersibility and the evaluation of adhesiveness are more excellent when the urea value of the step-polymerization-based polymer is more than 0 and not more than 0.5 mmol/g.

[ example 2]

An all-solid secondary battery was manufactured, and the following characteristics were evaluated. The results are shown in table 3.

< preparation of composition for positive electrode >

Into a 45mL vessel (manufactured by Fritsch Co., Ltd.) made of zirconia, 180 beads of zirconia having a diameter of 5mm were put, and 2.7g of the above synthesized LPS, 0.3g of KYNAR FLEX 2500-20 (trade name, PVdF-HFP: polyvinylidene fluoride hexafluoropropylene copolymer) in terms of solid content mass, and 22g of butyl butyrate were put. The vessel was set in a planetary ball mill P-7 (trade name) manufactured by Fritsch Co., Ltd and stirred at 25 ℃ and 300pm for 60 minutes. Then, 7.0g of LiNi was charged as a positive electrode active material_1/3Co_1/3Mn_1/3O₂(NMC) in the same way the vessel was placed in a planetary ball mill P-7 at 25 ℃ and a rotation speed of 100rpm was continuously mixed for 5 minutes, thereby preparing compositions for positive electrodes, respectively.

< production of Positive electrode sheet for all-solid-State Secondary Battery >

The composition for a positive electrode obtained above was applied to an aluminum foil (positive electrode current collector) having a thickness of 20 μm using a baking type applicator (trade name: SA-201, manufactured by ster SANGYO CO. ltd.), heated at 100 ℃ for 2 hours, and dried (dispersion medium removed) to obtain a composition for a positive electrode. Then, the dried composition for a positive electrode was pressurized at 25 ℃ (10MPa, 1 min) using a hot press to produce a positive electrode sheet for an all-solid-state secondary battery having a positive electrode active material layer with a film thickness of 80 μm.

< preparation of composition for negative electrode >

Into a 45mL vessel (manufactured by Fritsch co., Ltd) made of zirconia, 180 zirconia beads having a diameter of 5mm were put, and 4.0g of the synthesized LPS, 22g of a dispersion or solution (0.3 g in terms of solid content mass) of the polymer shown in table 3, and the dispersion medium shown in the table were put. The vessel was set in a planetary ball mill P-7 (trade name) manufactured by Fritsch Co., Ltd and stirred at 25 ℃ and 300pm for 60 minutes. Then, 5.3g of silicon (manufactured by Si Aldrich Co.) and 0.4g of acetylene black (manufactured by Denka Company) were put into the container as a negative electrode active material, and the mixture was placed in a planetary ball mill P-7 in the same manner, and further mixed at 25 ℃ and 100rpm for 10 minutes to prepare compositions U-1 to U-24 and V-1 to V-3 for negative electrodes, respectively.

[ Table 3]

Si: silicon (manufactured by Aldrich Co., Ltd.)

AB: acetylene black (manufactured by Denka Company)

THF: tetrahydrofuran (manufactured by FUJIFILM Wako Pure Chemical Corporation)

< production of negative electrode sheet for all-solid-state secondary battery >

The composition for a negative electrode obtained above was coated on a stainless steel foil (negative electrode current collector) having a thickness of 10 μm using a baking type applicator (trade name: SA-201, manufactured by ster SANGYO CO. ltd.), heated at 100 ℃ for 2 hours, and dried (dispersion medium removed) to obtain a composition for a negative electrode. Then, the dried composition for a negative electrode was pressurized at 25 ℃ (10MPa, 1 min) using a hot press to produce a negative electrode sheet for an all-solid-state secondary battery having a negative electrode active material layer with a film thickness of 50 μm.

Next, the solid electrolyte-containing sheets shown in the column of "solid electrolyte layer" in table 4 prepared in example 1 above were stacked on the negative electrode active material layer of each negative electrode sheet for all-solid secondary batteries shown in table 4 so that the solid electrolyte layer was in contact with the negative electrode active material layer, and after pressing and transfer (lamination) at 25 ℃ and 50Mpa using a press, pressing was performed at 25 ℃ and 600Mpa, negative electrode sheets PU-1 to PU-24 and PV-1 to PV-3 for all-solid secondary batteries having a solid electrolyte layer with a film thickness of 50 μm were prepared, respectively.

< manufacture of all-solid-state secondary battery >

Each of the fabricated negative electrode sheets for all-solid-state secondary batteries (aluminum foil from which the sheet containing the solid electrolyte was peeled) was cut into a disk shape having a diameter of 14.5mm, and as shown in fig. 2, the negative electrode sheet was put into a 2032-type button battery case 11 made of stainless steel into which a spacer and a gasket (not shown in fig. 2) were inserted, and a positive electrode sheet (positive electrode active material layer) punched out to have a diameter of 14.0mm was superimposed on the solid electrolyte layer. A stainless steel foil (negative electrode current collector) was further stacked thereon to form an all-solid-state secondary battery laminate 12 (a laminate composed of aluminum, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and stainless steel). Then, the 2032-type button cell case 11 was crimped, thereby producing all-solid-state secondary batteries 201 to 225 and c21 to c23 shown in fig. 2, respectively. The all-solid secondary battery 13 thus manufactured has a layer structure shown in fig. 1.

< evaluation 1: battery characteristic 1 (discharge capacity maintenance rate) >

The discharge capacity maintaining rate was measured as the battery characteristics of all-solid secondary batteries 201 to 225 and c21 to c23, and the cycle characteristics were evaluated.

In particular toIn other words, the charge/discharge evaluation device: TOSCAT-3000 (trade name, TOYO SYSTEM co., ltd. manufactured) measures the discharge capacity maintenance rate of each all-solid-state secondary battery. Charging is carried out until the current density reaches 0.1mA/cm²And the battery voltage reaches 4.2V. Discharging until the current density reaches 0.1mA/cm²And the battery voltage reaches 2.5V. The 1-time charge and 1-time discharge were taken as 1 charge and discharge cycle and the charge and discharge of 1 cycle were repeated and the all-solid secondary battery was initialized. When the discharge capacity (initial discharge capacity) of charge and discharge at the 1 st cycle after initialization was set to 100%, the number of charge and discharge cycles at which the discharge capacity maintenance rate (discharge capacity with respect to the initial discharge capacity) reached 80% was evaluated by including the cycle characteristics in which evaluation level described below.

In this test, the discharge capacity maintaining rate was judged to be not less than the evaluation level "4" and was judged to be acceptable.

The initial discharge capacities of all-solid secondary batteries 201 to 225 all showed sufficient values to function as all-solid secondary batteries.

Evaluation of the maintenance rate of discharge Capacity-

8: number of charge and discharge cycles of 100 cycles or less

7: the number of charging and discharging cycles is less than or equal to 50 cycles and less than 100 cycles

6: the number of charging and discharging cycles is less than or equal to 30 cycles and less than 50 cycles

5: the number of charging and discharging cycles is more than or equal to 20 cycles and less than or equal to 30 cycles

4: the number of charging and discharging cycles is more than or equal to 10 cycles and less than 20 cycles

3: the number of charging and discharging cycles is less than or equal to 5 cycles and less than or equal to 10 cycles

2: the number of charging and discharging cycles is less than or equal to 2 cycles and less than 5 cycles

1: the number of charging and discharging cycles is less than 2 cycles

< evaluation 2: battery characteristic 2 (resistance) >

The resistance of all-solid secondary batteries 201 to 214 and c21 to c23 was measured as battery characteristics, and the level of resistance was evaluated.

Using a charge/discharge evaluation device: TOSCAT-3000 (trade name, TOYO SYSTEM co., ltd.) evaluates the resistance of each all-solid-state secondary battery. Charging is carried out until the current density reaches 0.1mA/cm²And the battery voltage reaches 4.2V. Discharging until the current density reaches 0.2mA/cm²And the battery voltage reaches 2.5V. The 1-time charge and 1-time discharge were repeated for 2 cycles of charge and discharge as 1 cycle of charge and discharge, and the cell voltage after discharge at 5mAh/g (amount of electricity per 1g mass of active material) of the 2 nd cycle was read. The battery voltage was evaluated by which evaluation level the resistance of the all-solid secondary battery was included in. Higher cell voltages indicate lower resistance. In this test, the evaluation level "4" or more was acceptable.

Evaluation of the resistance-

8: battery voltage not greater than 4.1V

7: the battery voltage is not less than 4.0V and less than 4.1V

6: the battery voltage is less than or equal to 4.0V and less than or equal to 3.9V

5: the battery voltage is less than or equal to 3.7V and less than 3.9V

4: the battery voltage is less than or equal to 3.7V and less than or equal to 3.5V

3: the battery voltage is less than or equal to 3.2V and less than 3.5V

2: the battery voltage is less than or equal to 2.5V and less than 3.2V

1: can not be charged and discharged

< evaluation 3: active material volume >

The theoretical capacity of the active material was calculated and evaluated as follows as the battery characteristics of all-solid secondary batteries 201 to 224 and c21 to c 23. Higher capacity indicates higher energy density.

Calculation of the theoretical Capacity-

Calculated from the saturated composition at the time of lithium intercalation.

Graphite: since graphite is C → LiC₆Therefore, the Li insertion amount per 1g of graphite became 1340 (coulomb) ([ (1(g)/6 (Li insertion amount per graphite molecule))/12 (graphite molecular weight)]X 96500 (faraday constant)).

Since 3.6 coulombs are 1mAh, the theoretical capacity of graphite becomes 372(mAh/g) (1340/3.6).

Silicon: since silicon is Si → Li_4.4Si, so that the Li insertion amount per 1g of silicon becomes 15110 coulomb (1 (g). times.4.4 (Li insertion amount per silicon molecule))/28.1 (silicon molecular weight)]X 96500 (faraday constant)).

Therefore, the theoretical capacity of silicon becomes 4197(mAh/g) (15110/3.6).

Evaluation scale-

5: theoretical capacity of active matter not more than 1500mAh/g

4: the theoretical capacity of the active substance is less than or equal to 1200mAh/g and less than 1500mAh/g

3: the theoretical capacity of the active substance is less than or equal to 800mAh/g and less than 1200mAh/g

2: the theoretical capacity of the active substance is less than or equal to 400mAh/g and less than 800mAh/g

1: the theoretical capacity of the active substance is less than or equal to 400mAh/g

[ Table 4]

As is clear from table 4, the all-solid secondary battery of the comparative example had a low discharge capacity maintenance rate and a large resistance. In contrast, the discharge capacity maintenance rate of the present invention is high and the resistance is low.

It is also known that when silicon is used as the negative electrode active material, a high energy density is exhibited.

In the solid electrolyte composition C-2, an oxide-based inorganic solid electrolyte (Li) was used in place of LPS₇La₃Zr₂O₁₂(Toshima Manufacturing co., ltd.)), the results of the above dispersibility were evaluated to be good for a solid electrolyte composition prepared in the same manner as the above solid electrolyte composition C-2 except for the above. The solid electrolyte-containing sheet produced using the solid electrolyte composition was evaluated to have good adhesion and ion conductivity.

In the composition U-2 for a negative electrode, an oxide-based inorganic solid electrolyte (Li) was used in place of LPS₇La₃Zr₂O₁₂(Toshima Manufacturing co., ltd.)), a negative electrode composition a was prepared in the same manner as the negative electrode composition U-2. An all-solid secondary battery was produced in the same manner as the all-solid secondary battery 202 except that the composition a for a negative electrode was used in place of the composition U-2 for a negative electrode in the all-solid secondary battery 202. The all-solid secondary battery was evaluated to have good discharge capacity maintenance rate and resistance.

The results of evaluating the discharge capacity maintenance rate and the resistance of the positive electrode sheet and the all-solid-state secondary battery into which the positive electrode sheet was inserted were good using the adhesive specified in the present invention.

The present invention has been described in connection with the embodiments thereof, but unless otherwise specified, the invention is not limited to any of the details of the description, and should be construed broadly without departing from the spirit and scope of the invention as set forth in the appended claims.

The present application claims priority based on japanese patent application 2018-2454977, which was filed in japanese patent application at 2018, 12, 27, the contents of which are hereby incorporated by reference as part of the present specification.

Description of the symbols

1-negative electrode current collector, 2-negative electrode active material layer, 3-solid electrolyte layer, 4-positive electrode active material layer, 5-positive electrode current collector, 6-working site, 10-all-solid-state secondary battery, 11-2032 button cell case, 12-sample for measuring ionic conductivity or laminate for all-solid-state secondary battery, 13-sample for measuring ionic conductivity or all-solid-state secondary battery.

Claims

1. A solid electrolyte composition comprising:

an inorganic solid electrolyte having conductivity of an ion of a metal belonging to group 1 or group 2 of the periodic table;

an adhesive comprising: a stepwise polymerization polymer having a constituent component represented by the following formula (H-1); and

the dispersion medium is a mixture of a dispersion medium,

[ chemical formula 1]

In the formula, L¹¹Represents an alkylene group having 1 to 12 carbon atoms, an arylene group having 6 to 18 carbon atoms, an alkenylene group having 2 to 12 carbon atoms, a 2-valent heterocyclic group having 4 to 18 carbon atoms, an oxygen atom, a carbonyl group, or-N (R)^N1) Or an imine linking group or a combination thereof, X¹¹And X¹²Represents an oxygen atom, a sulfur atom or-N (R)^N1) -, in which X¹¹And X¹²Different from each other, R^N1Represents a hydrogen atom, an alkylsilyl group, an aryl group having 6 to 18 carbon atoms or an alkyl group having 1 to 12 carbon atoms.

2. The solid electrolyte composition of claim 1,

the stepwise polymerization type polymer has a partial structure represented by the following formula (H-2),

[ chemical formula 2]

In the formula, L²¹With the meaning of (A) and (B)¹¹Are as defined above, R^N2With the meaning of (A) and the R^N1The term "a" means a bonding portion for introducing the partial structure into the stepwise polymerization-based polymer.

3. The solid electrolyte composition according to claim 1 or 2,

the stepwise polymerization type polymer has a partial structure represented by the following formula (H-3),

[ chemical formula 3]

L³¹An alkylene group having 1 to 12 carbon atoms, an arylene group having 6 to 12 carbon atoms, an oxygen atom, an imine linking group, or a combination thereof, and a group having a molecular weight of 400 or less, wherein the group represents a bonding portion for introducing the partial structure into the stepwise polymerization-based polymer.

4. The solid electrolyte composition according to any one of claims 1 to 3, wherein,

the stepwise polymerization type polymer is a polymer represented by the following formula,

[ chemical formula 4]

In the formula, L¹Represents a molecular chain having a molecular weight of 14 or more and 200,000 or less,

X¹、X²and L²Are each as defined for X¹¹The X¹²And said L¹¹The meaning of (A) is the same as that of (B),

X³and X⁴All represent-NH-or an oxygen atom, L³Represents a hydrocarbon group, and represents a hydrocarbon group,

X⁵and X⁶All represent-NH-or an oxygen atom, L⁴Represents a polycarbonate chain, a polyester chain or a polyalkylene oxide chain,

X⁷and X⁸All represent-NH-or an oxygen atom, L⁵Which is a representation of a hydrocarbon polymer chain,

s1 to s5 represent the contents of the respective constituent components, and the total is 100 mass%.

5. The solid electrolyte composition of any one of claims 1 to 4,

the urea value of the stepwise polymerization polymer is more than 0 and 0.5mmol/g or less.

6. The solid electrolyte composition of any one of claims 1 to 5, wherein,

the binder is particles having an average particle diameter of 5nm or more and 10 μm or less.

7. The solid electrolyte composition of any one of claims 1 to 6, wherein,

the content of the binder in the total solid content of the solid electrolyte composition is 0.001-10 mass%.

8. The solid electrolyte composition of any one of claims 1 to 7,

the step-growth polymerization type polymer has at least one functional group selected from the following functional group (I),

< group of functional groups (I) >)

Carboxyl, sulfonic group, keto group, phosphoric group.

9. The solid electrolyte composition of any one of claims 1 to 8,

10. The solid electrolyte composition according to any one of claims 1 to 9, which contains a conduction aid.

11. The solid electrolyte composition according to any one of claims 1 to 10, comprising an active material.

12. The solid electrolyte composition of claim 11,

13. The solid electrolyte composition of any one of claims 1 to 12,

the inorganic solid electrolyte is a sulfide-based inorganic solid electrolyte represented by the following formula (1),

formula (1): l is_a1M_bP_cS_dA_e

Wherein L represents an element selected from Li, Na and K, 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, a 1-e 1 represents the composition ratio of the elements, and a1: B1: c1: d1: e1 satisfies 1-12: 0-5: 1: 2-12: 0-10.

14. The solid electrolyte composition of any one of claims 1 to 13, wherein,

15. A solid electrolyte-containing sheet having a layer composed of the solid electrolyte composition described in any one of claims 1 to 14.

16. An all-solid-state secondary battery comprising a positive electrode active material layer, a negative electrode active material layer and a solid electrolyte layer in this order,

at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer is composed of the solid electrolyte composition according to any one of claims 1 to 14.

17. A method of manufacturing a solid electrolyte-containing sheet, comprising: a process of coating the solid electrolyte composition according to any one of claims 1 to 14.

18. A method of manufacturing an all-solid secondary battery, comprising: a process of coating the solid electrolyte composition according to any one of claims 1 to 14.