KR20210138068A - All-solid-state secondary battery sheet and all-solid-state secondary battery manufacturing method, and all-solid-state secondary battery sheet and all-solid-state secondary battery - Google Patents

Abstract

A method for producing a sheet for an all-solid secondary battery containing a sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 μm or less and a particulate organic component, comprising: a particulate organic component and a sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 μm or less, the above A mixture in which the content of the particulate organic component is 15% by mass or less of the total content of the sulfide-based inorganic solid electrolyte and the particulate organic component is 20°C or more higher than the glass transition temperature of the particulate organic component, A method for manufacturing a sheet for an all-solid secondary battery comprising pressurizing at a temperature below the decomposition temperature at a pressure higher than 1/10 of the elastic modulus of the particulate organic component, a method for manufacturing an all-solid secondary battery, and an all-solid Sheets for secondary batteries and all-solid-state secondary batteries.

Description

All-solid-state secondary battery sheet and all-solid-state secondary battery manufacturing method, and all-solid-state secondary battery sheet and all-solid-state secondary battery

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

In an all-solid-state secondary battery, all of the negative electrode, the electrolyte, and the positive electrode are made of a solid, and it is expected that the problems of safety and reliability, which are problems of batteries using an organic electrolyte, can be greatly improved. In addition, it becomes possible to increase the lifespan. In addition, the all-solid-state secondary battery can have a structure in which an electrode and an electrolyte are directly arranged and arranged in series. Therefore, compared with the secondary battery using an organic electrolyte solution, high energy density-ization is attained, and application to an electric vehicle, a large-sized storage battery, etc. is anticipated.

In such an all-solid-state secondary battery, any one of the constituent layers (solid electrolyte layer, negative electrode active material layer, and positive electrode active material layer) is a layer containing an inorganic solid electrolyte and a binder (binder) made of a specific polymer. It is proposed to do. As the sheet used for the constituent layer, for example, Patent Document 1 discloses an inorganic solid electrolyte (A) having ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and a urethane bond in the main chain , urea bond, amide bond, imide bond, and ester bond at least one type of bond, and further contains a polymer (B) having a graft structure, and, if necessary, a sheet containing a solid electrolyte containing an active material (D) is described.

Patent Document 1: International Publication No. 2018/151161

In the case of forming the constituent layer of an all-solid-state secondary battery with solid particles (inorganic solid electrolyte, solid particle, conductive aid, etc.), in general, in the constituent layer formed of solid particles, the interfacial contact state between the solid particles is insufficient. resistance tends to increase. Moreover, when the binding property of solid particles by a binder is weak, the contact defect of solid particles will be caused. Further, when the active material expands and contracts due to charging and discharging, poor contact between the active material layer and the solid electrolyte layer occurs. In addition, if the binding property between the solid particles and the current collector is weak, poor contact between the active material layer and the current collector is also caused. When these contact failures occur, the resistance of the all-solid-state secondary battery increases (battery performance decreases).

The solid electrolyte-containing sheet described in Patent Document 1 has high binding property between solid particles and is excellent in ion conductivity, and this sheet can impart excellent properties to an all-solid secondary battery.

However, in recent years, research and development, such as high performance and practical use of electric vehicles, has progressed rapidly, and cycle characteristics, rate characteristics, etc. are also increasing as battery performance required for an all-solid-state secondary battery. Therefore, development of the all-solid-state secondary battery which exhibits more excellent battery performance by improving the binding property between solid particles further, etc. is calculated|required.

The present invention provides a method for manufacturing a sheet for an all-solid-state secondary battery, which can impart excellent battery performance to an all-solid-state secondary battery by increasing the binding property between solid particles by using it as a constituent layer of an all-solid-state secondary battery, and this manufacturing method It is an object to provide a method for manufacturing the used all-solid-state secondary battery. Moreover, this invention makes it a subject to provide the all-solid-state secondary battery which shows the outstanding battery performance.

As a result of repeated various studies, the present inventors have made solid particles by heating and pressing a mixture containing a sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 μm or less and a particulate organic component in a specific mass ratio under specific temperature and specific pressure conditions. It discovered that the sheet|seat for all-solid-state secondary batteries excellent in the binding property of a liver could be manufactured. Moreover, by using this sheet|seat for all-solid-state secondary batteries as a structural layer of an all-solid-state secondary battery, it discovered that the outstanding battery performance could be provided to an all-solid-state secondary battery. The present invention has been further studied and completed based on these findings.

That is, the above problem was solved by the following means.

<1>

A method for producing a sheet for an all-solid secondary battery comprising a sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 μm or less and a particulate organic component, the method comprising:

A mixture comprising a particulate organic component and a sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 µm or less, wherein the content of the particulate organic component is 15% by mass or less of the total content of the sulfide-based inorganic solid electrolyte and the particulate organic component At a temperature 20° C. or more higher than the glass transition temperature of the particulate organic component and less than the decomposition temperature of the particulate organic component, pressurizing at a pressure higher than 1/10 of the elastic modulus of the particulate organic component, The manufacturing method of the sheet|seat for all-solid-state secondary batteries.

<2>

The said elastic modulus is 150 Mpa or more, The manufacturing method of the sheet|seat for all-solid-state secondary batteries as described in <1>.

<3>

The method for producing a sheet for an all-solid secondary battery according to <1> or <2>, wherein the sulfide-based inorganic solid electrolyte and the particulate organic component satisfy the relationship defined by the following formula (I) with respect to a volume average particle diameter.

Ba<SEa<20Ba Formula (I)

In the formula, SEa is the volume average particle diameter of the sulfide-based inorganic solid electrolyte, and Ba is the volume average particle diameter of the particulate organic component.

<4>

The manufacturing method of the sheet|seat for all-solid-state secondary batteries in any one of <1>-<3> including the process of adjusting the sulfide-type inorganic solid electrolyte which comprises the said mixture to a volume average particle diameter of 1.0 micrometer or less.

<5>

The manufacturing method of the sheet|seat for all-solid-state secondary batteries in any one of <1>-<4> in which the said mixture contains an active material.

<6>

The manufacturing method of the sheet|seat for all-solid-state secondary batteries as described in <5> whose said active material is a negative electrode active material.

<7>

The manufacturing method of the sheet|seat for all-solid-state secondary batteries as described in <6> in which the said negative electrode active material contains a silicon element or a tin element.

<8>

The said glass transition temperature is 30 degreeC or more, The manufacturing method of the sheet|seat for all-solid-state secondary batteries in any one of <1>-<7>.

<9>

The manufacturing method of the sheet|seat for all-solid-state secondary batteries in any one of <1>-<8> which pressurizes the said mixture at the temperature 50 degreeC or more higher than the said glass transition temperature.

<10>

The mixture contains a dispersion medium, and the manufacturing method includes the step of heating the mixture without completely removing the dispersion medium before the pressurization, the sheet for all-solid secondary batteries according to any one of <1> to <9>. manufacturing method.

<11>

A method for manufacturing an all-solid-state secondary battery comprising a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, the method comprising:

The sheet for an all-solid-state secondary battery obtained by the method for manufacturing the sheet for an all-solid-state secondary battery according to any one of <1> to <10> is at least one of the positive electrode active material layer, the solid electrolyte layer and the negative electrode active material layer, The manufacturing method of the all-solid-state secondary battery including the process of including.

<12>

The sheet for all-solid-state secondary batteries obtained by the manufacturing method of the sheet|seat for all-solid-state secondary batteries in any one of <1>-<10>.

<13>

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

An all-solid-state secondary battery, wherein at least one layer of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is a layer composed of the all-solid-state secondary battery sheet according to <12>.

The manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention can manufacture the sheet|seat for all-solid-state secondary batteries excellent in binding property. The manufacturing method of the all-solid-state secondary battery of this invention can manufacture the all-solid-state secondary battery which shows the outstanding battery performance. Moreover, the sheet for all-solid-state secondary batteries of this invention shows strong binding property of solid particles, and the all-solid-state secondary battery of this invention shows excellent battery performance.

1 is a longitudinal cross-sectional view schematically showing an all-solid-state secondary battery according to a preferred embodiment of the present invention.
Fig. 2 is a longitudinal cross-sectional view schematically showing an all-solid-state secondary battery (coin battery) produced in Examples.

In this specification, the numerical range indicated using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

The manufacturing method of the sheet for all-solid secondary batteries of this invention is a manufacturing method of the sheet for all-solid-state secondary batteries containing a sulfide-type inorganic solid electrolyte with a volume average particle diameter of 1.0 micrometer or less, and a particulate organic component, A particulate organic component and a volume average particle diameter of 1.0 A mixture containing a sulfide-based inorganic solid electrolyte of μm or less, wherein the content of the particulate organic component is 15% by mass or less of the total content of the sulfide-based inorganic solid electrolyte and the particulate organic component, free of the particulate organic component This includes pressurizing at a pressure higher than the transition temperature by 20°C or more and lower than the decomposition temperature of the particulate organic component at a pressure higher than 1/10 of the elastic modulus of the particulate organic component. This step can be performed in the same manner as the following step (3).

The manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention, Preferably, it has each following process.

Particle size adjustment step (hereinafter also referred to as step (1)):

Step of adjusting the volume average particle diameter of the sulfide-based inorganic solid electrolyte to 1.0 μm or less

Mixing process (the process of preparing a mixture, hereafter also called process (2).):

In the particulate organic component and the sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 µm or less obtained in the above step, the content of the particulate organic component is 15% by mass in the total content of the sulfide-based inorganic solid electrolyte and the particulate organic component The process of mixing so as to be as follows

Pressurization step (hereinafter also referred to as step (3)):

The mixture obtained by the step of mixing at a temperature higher than the glass transition temperature of the particulate organic component by at least 20°C and lower than the decomposition temperature of the particulate organic component at a pressure higher than 1/10 of the elastic modulus of the particulate organic component pressurizing process

In the manufacturing method of the all-solid-state secondary battery sheet of this invention, the said process (1) is not essential, and when the volume average particle diameter of the sulfide-type inorganic solid electrolyte used in the said process (2) exceeds 1.0 micrometer, furthermore, a sulfide When it is desired to readjust the volume average particle diameter of a system inorganic solid electrolyte, the manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention performs a process (1). This step is usually performed before the step of mixing, but may be performed during the step of mixing (the volume average particle diameter of the sulfide-based inorganic solid electrolyte may be adjusted by mixing in the step of mixing).

For example, in the step (1), when the volume average particle diameter of the sulfide-based inorganic solid electrolyte and the particulate organic component used in the step (2) does not satisfy the relationship defined by the following formula (I), the sulfide-based inorganic component It is preferable to adjust the volume average particle diameter of the solid electrolyte and the volume average particle diameter of the particulate organic component as necessary to satisfy the relationship defined by the following formula (I).

Ba<SEa<20Ba Formula (I)

In the formula, SEa is the volume average particle diameter of the sulfide-based inorganic solid electrolyte, and Ba is the volume average particle diameter of the particulate organic component.

Hereinafter, the sheet for all-solid-state secondary batteries which has an electrode active material layer (a positive electrode active material layer or a negative electrode active material layer) may be called an electrode sheet (a positive electrode sheet or a negative electrode sheet). On the other hand, the sheet for all-solid secondary batteries which has a solid electrolyte layer may be called the sheet|seat for solid electrolyte layers. In addition, the sheet|seat for all-solid-state secondary batteries which has an electrode active material layer and a solid electrolyte layer is called an electrode sheet.

<Ingredients>

Hereinafter, the component used for the manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention, and the component which can be used are demonstrated.

(sulfide-based inorganic solid electrolyte)

In the present invention, the inorganic solid electrolyte is an inorganic solid electrolyte, and the solid electrolyte is a solid electrolyte capable of moving ions therein. Since the main ion conductive material does not contain an organic material, an organic solid electrolyte (a polymer electrolyte represented by polyethylene oxide (PEO), etc., an organic material represented by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), etc.) electrolyte salts). In addition, since the inorganic solid electrolyte is a solid in a normal state, it is not normally dissociated or liberated into cations and anions. In this regard, it is _{clearly distinguished from inorganic electrolyte salts (LiPF 6} , LiBF ₄ , lithium bis(fluorosulfonyl)imide (LiFSI), LiCl, etc.) do. The inorganic solid electrolyte is not particularly limited as long as it has ion conductivity of a metal belonging to Group 1 or 2 of the periodic table, and generally does not have electron conductivity. When the all-solid-state secondary battery of the present invention is a lithium ion battery, the inorganic solid electrolyte preferably has ion conductivity of lithium ions.

As the inorganic solid electrolyte, a solid electrolyte material normally used for an all-solid secondary battery can be appropriately selected and used. Examples of the inorganic solid electrolyte include (i) a sulfide-based inorganic solid electrolyte, (ii) an oxide-based inorganic solid electrolyte, (iii) a halide-based inorganic solid electrolyte, and (iv) a hydride-based inorganic solid electrolyte.

Hereinafter, the (i) sulfide-based inorganic solid electrolyte used in the step (1) will be described. In addition, within the scope not impairing the effects of the present invention, (i) together with a sulfide-based inorganic solid electrolyte, (ii) an oxide-based inorganic solid electrolyte, (iii) a halide-based inorganic solid electrolyte, and (iv) hydrogenation A water-based inorganic solid electrolyte may be used.

(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 contains at least Li, S and P as elements and preferably has lithium ion conductivity, but may contain elements other than Li, S and P depending on the purpose or case.

Examples of the sulfide-based inorganic solid electrolyte include lithium ion conductive inorganic solid electrolytes satisfying the composition represented by the following formula (1).

L _a1 M _b1 P _c1 S _d1 A _e1 (1)

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. a1 to e1 represent the compositional ratio of each element, and a1:b1:c1:d1:e1 satisfies 1 to 12:0 to 5:1:2 to 12:0 to 10. 1-9 are preferable and, as for a1, 1.5-7.5 are more preferable. 0-3 are preferable and, as for b1, 0-1 are more preferable. 2.5-10 are preferable and, as for d1, 3.0-8.5 are more preferable. 0-5 are preferable and, as for e1, 0-3 are more preferable.

The composition ratio of each element can be controlled by adjusting the compounding quantity of the raw material compound at the time of manufacturing a sulfide type inorganic solid electrolyte as follows.

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

The sulfide-based inorganic solid electrolyte is, for example, lithium sulfide (Li ₂ S), phosphorus sulfide (eg, diphosphorus pentasulfide (P ₂ S ₅ )), simple phosphorus, single sulfur, sodium sulfide, hydrogen sulfide. , lithium halide (eg, LiI, LiBr, LiCl) and the sulfide of the element represented by M (eg, SiS ₂ , SnS, GeS ₂ ) may be prepared by reacting at least two or more raw materials.

Ratio of Li-PS-based glass and Li-PS system in the glass-ceramics, Li ₂ S and P ₂ S ₅ is, Li ₂ S: P ₂ at a molar ratio of S _5, preferably 60: 40 to 90: 10 , More preferably 68:32 to 78:22. By making the ratio of Li ₂ S and P ₂ S ₅ into this range, lithium ion conductivity can be made high. Specifically, the lithium ion conductivity may be preferably 1×10 ⁻⁴ S/cm or more, more preferably 1×10 ⁻³ S/cm or more. Although there is no particular upper limit, it is practical that it is ^{1x10 -1 S/cm or less.}

As a specific example of a sulfide-based inorganic solid electrolyte, a combination example of a raw material is shown below. For example, Li ₂ SP ₂ S ₅ , Li ₂ SP ₂ S ₅ -LiCl, Li ₂ SP ₂ S ₅ -H ₂ S, Li ₂ SP ₂ S ₅ -H ₂ S-LiCl, Li ₂ S-LiI- P ₂ S ₅ , Li ₂ S-LiI-Li ₂ OP ₂ S ₅ , Li ₂ S-LiBr-P ₂ S ₅ , Li ₂ S-Li ₂ OP ₂ S ₅ , Li ₂ S-Li ₃ PO ₄ -P ₂ S ₅ , Li ₂ SP ₂ S ₅ -P ₂ O ₅ , Li ₂ SP ₂ S ₅ -SiS ₂ , Li ₂ SP ₂ S ₅ -SiS ₂ -LiCl, Li ₂ SP ₂ S ₅ -SnS, Li ₂ SP ₂ S ₅ -Al ₂ S ₃ , Li ₂ S-GeS ₂ , Li ₂ S-GeS ₂ -ZnS, Li ₂ S-Ga ₂ S ₃ , Li ₂ S-GeS ₂ -Ga ₂ S ₃ , Li ₂ S- GeS ₂ -P ₂ S ₅ , Li ₂ S-GeS ₂ -Sb ₂ S ₅ , Li ₂ S-GeS ₂ -Al ₂ S ₃ , Li ₂ S-SiS ₂ , Li ₂ S-Al ₂ S ₃ , Li ₂ S-SiS ₂ -Al ₂ S ₃ , Li ₂ S-SiS ₂ -P ₂ S ₅ , Li ₂ S-SiS ₂ -P ₂ S ₅ -LiI, Li ₂ S-SiS ₂ -LiI, Li ₂ S-SiS _{2 -Li 4} SiO ₄ , Li ₂ S-SiS ₂ -Li ₃ PO ₄ , Li ₁₀ GeP ₂ S ₁₂ , and the like. However, the mixing ratio of each raw material does not matter. Examples of a method for synthesizing a sulfide-based inorganic solid electrolyte material using such a raw material composition include an amorphization method. Examples of the amorphization method include a mechanical milling method, a solution method, and a melt quenching method. This is because processing at room temperature becomes possible and the manufacturing process can be simplified.

(ii) oxide-based inorganic solid electrolyte

The oxide-based inorganic solid electrolyte preferably contains an oxygen atom, has ion conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and has electronic insulation properties.

The oxide-based inorganic solid electrolyte has an ionic conductivity of ^{preferably 1×10 -6} S/cm or more, more preferably 5×10 ^-6 S/cm or more, and ^{particularly preferably 1×10 -5} S/cm or more. do. Although the upper limit is not particularly limited, it ^{is practical that it is 1×10 −1} S/cm or less.

Specific examples of the compound include, for example, Li _xa La _ya TiO ₃ [xa satisfies 0.3≤xa≤0.7, and ya satisfies 0.3≤ya≤0.7] (LLT); Li _xb La _yb Zr _zb M ^bb _mb O _nb (M ^bb is at least one element selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In and Sn. xb is 5≤xb ≤10, yb satisfies 1≤yb≤4, zb satisfies 1≤zb≤4, mb satisfies 0≤mb≤2, and nb satisfies 5≤nb≤20. ); Li _xc B _yc M ^cc _zc O _nc (M ^cc is at least one element selected from C, S, Al, Si, Ga, Ge, In and Sn. xc satisfies 0<xc≤5, and yc is 0<yc≤1, zc satisfies 0<zc≤1, nc satisfies 0<nc≤6); Li _xd (Al,Ga) _yd (Ti,Ge) _zd Si _ad P _md O _nd (xd satisfies 1≤xd≤3, yd satisfies 0≤yd≤1, zd is 0≤zd≤2 , ad satisfies 0≤ad≤1, md satisfies 1≤md≤7, and nd satisfies 3≤nd≤13); Li _(3-2xe) combinations of M ^ee _xe D ^ee O (xe halogen atom represents a number of 0 to 0.1, to M represents a divalent metal atom ^{ee. Ee} D is a halogen atom or to two or more of indicates); Li _xf Si _yf O _zf (xf satisfies 1≤xf≤5, yf satisfies 0<yf≤3, and zf satisfies 1≤zf≤10); Li _xg S _yg O _zg (xg satisfies 1≤xg≤3, yg satisfies 0<yg≤2, and zg satisfies 1≤zg≤10); Li ₃ BO ₃ ; Li ₃ BO ₃ -Li ₂ SO ₄ ; Li ₂ OB ₂ O ₃ —P ₂ O ₅ ; Li ₂ O—SiO ₂ ; Li ₆ BaLa ₂ Ta ₂ O ₁₂ ; Li ₃ PO _(4-3/2w) N _w (w is w<1); _{Li 3.5} Zn _0.25 GeO ₄ having a LISICON (Lithium super ionic conductor) type crystal structure; _{La 0.55} Li _0.35 TiO ₃ having a perovskite crystal structure; _{LiTi 2} P ₃ O ₁₂ having a Natrium super ionic conductor (NASICON) type crystal structure; Li _1+xh+yh (Al,Ga) _xh (Ti,Ge) _2-xh Si _yh P _3-yh O ₁₂ (xh satisfies 0≤xh≤1, yh satisfies 0≤yh≤1 .); _{Li 7} La ₃ Zr ₂ O ₁₂ (LLZ) having a garnet-type crystal structure, and the like.

Moreover, the phosphorus compound containing Li, P and O is also preferable. lithium phosphate (Li ₃ PO ₄ ); LiPON in which some of the oxygen atoms of lithium phosphate are substituted with nitrogen; LiPOD ¹ (D ¹ is, preferably, one or more selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt and Au element.) and the like.

Further, LiA ¹ ON (A ¹ is at least one element selected from Si, B, Ge, Al, C, and Ga.) and the like can also be preferably used.

(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.

Examples of halide-based inorganic solid electrolyte to be, not particularly limited, and for example, there may be mentioned compounds such as _{Li 3 YBr 6, Li 3 YCl} 6 described in LiCl, LiBr, LiI, ADVANCED MATERIALS, 2018, 30, 1803075 . Among them, Li ₃ YBr ₆ and Li ₃ YCl ₆ are preferable.

(iv) hydride-based inorganic solid electrolyte

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

As the hydrogenated water system an inorganic solid electrolyte is not particularly limited, and for _{example, LiBH 4, Li 4 (BH} 4) , and the like ₃ I, 3LiBH ₄ -LiCl.

In step (1), 1 type may be mixed with the sulfide-type inorganic solid electrolyte, and 2 or more types may be mixed.

The mass (mg) (weight per unit area) of the sulfide-based inorganic solid electrolyte per ^{unit area (cm 2} ) of the solid electrolyte layer sheet is not particularly limited. According to the designed battery capacity, it can be appropriately determined, for example, 1-100 mg/cm ² It can be set as.

On the other hand, in the electrode active material layer of an electrode sheet, it is preferable that the total amount of an active material and a sulfide-type inorganic solid electrolyte is the said range as for the weight per unit area of a sulfide-type inorganic solid electrolyte.

The content of the sulfide-based inorganic solid electrolyte in the solid electrolyte layer sheet is preferably 50% by mass or more, more preferably 70% by mass or more, based on 100% by mass of solid content, from the viewpoint of reducing interfacial resistance and binding properties, 90 It is especially preferable that it is mass % or more. As an upper limit, from a similar viewpoint, it is preferable that it is 99.9 mass % or less, It is more preferable that it is 99.5 mass % or less, It is especially preferable that it is 99 mass % or less.

On the other hand, in the electrode sheet, as for content of the sulfide-type inorganic solid electrolyte in an electrode active material layer, it is preferable that total content of an active material and a sulfide-type inorganic solid electrolyte is the said range.

In the present specification, the solid content (solid component) refers to a mixture containing the particulate organic component in an amount of 15% by mass or less of the total content of the sulfide-based inorganic solid electrolyte and the particulate organic component (hereinafter referred to as “in the present invention”). The mixture used" refers to a component that does not disappear due to volatilization or evaporation when the mixture is dried at 170° C. for 6 hours under an atmospheric pressure of 1 mmHg and a nitrogen atmosphere. Typically, components other than the dispersion medium mentioned later are pointed out.

(particulate organic component)

The particulate organic component (preferably a binder) is not particularly limited, but a particulate polymer having a glass transition temperature is preferable. Hereinafter, the particulate polymer used in the step (2) will be described.

As the particulate polymer constituting the particulate organic component, a polymer having at least one of a urethane bond, a urea bond, an amide bond, and an imide bond, or a (meth)acrylic polymer is preferable. Among them, from the viewpoint of adhesion to the sulfide-based inorganic solid electrolyte, a polymer having a urethane bond and a (meth)acrylic polymer are more preferable.

In the present invention, as the particulate polymer, polyurethane, polyurethane, polyamide, polyimide, or (meth)acrylic polymer is preferable, polyurethane or acrylic polymer is more preferable, and polyurethane is more preferable. .

Although flat shape, amorphous form, etc. may be sufficient as a particulate-form organic component, spherical shape or granular form is preferable.

Although the urethane content in particular of the said polyurethane is not restrict|limited, It is preferable that it is 1.5 mmol/g or more, and 2.0 mmol/g or more is more preferable. On the other hand, it is preferable that the upper limit of urethane is 5 mmol/g or less from a viewpoint of providing particulate-formation stability.

The urethane may be determined by the method described in the section of Examples below.

The mass average molecular weight of the particulate polymer is not particularly limited. For example, 10,000 or more are preferable, 20,000 or more are more preferable, and 30,000 or more are still more preferable. As an upper limit, 2,000,000 or less are preferable, 1,500,000 or less are more preferable, 1,000,000 or less are still more preferable, and 200,000 or less are especially preferable.

-Measurement of molecular weight-

In this invention, the mass average molecular weight measures the mass average molecular weight of standard polystyrene conversion by gel permeation chromatography (GPC). As a measurement method, let it be the value measured basically by the method of the following condition 1 or condition 2 (priority). However, depending on the type of polymer (specific polymer, etc.) to be measured, an appropriate eluent may be selected and used.

(Condition 1)

Column: Connect two TOSOH TSKgel Super AWM-H.

Carrier: 10 mM LiBr/N-methylpyrrolidone

Measuring temperature: 40℃

Carrier flow: 1.0ml/min

Sample concentration: 0.1% by mass

Detector: RI (Refractive Index) Detector

(Condition 2)

Column: A column connected to TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, and TOSOH TSKgel Super HZ2000 is used.

Carrier: tetrahydrofuran

Measuring temperature: 40℃

Carrier flow: 1.0ml/min

Sample concentration: 0.1% by mass

Detector: RI (Refractive Index) Detector

The glass transition temperature of the particulate polymer is not particularly limited, but in order to maintain the particle shape and not cover the entire surface of the solid particles, it is preferably 30°C or higher, more preferably 35°C or higher, and 40°C or higher. more preferably. Let the glass transition temperature be a value measured by the method demonstrated in the Example mentioned later. In the present invention, the glass transition temperature used as a reference of the heating temperature in the step (3) is the highest glass transition temperature when the particulate polymer has a plurality of glass transition temperatures.

Although the decomposition temperature in particular of a particulate-form polymer is not restrict|limited, From the point of balance with a heating process, 150 degreeC or more is preferable, 180 degreeC or more is more preferable, and 190 degreeC or more is still more preferable. It is preferable that it is 500 degrees C or less, and, as for an upper limit, it is more preferable that it is 480 degrees C or less, It is more preferable that it is 450 degrees C or less. The decomposition temperature is a value measured by the method described in Examples to be described later.

Although the elastic modulus in particular of a particulate-form polymer is not restrict|limited, It is preferable that it is 150 MPa or more, It is more preferable that it is 180 MPa or more, It is more preferable that it is 200 MPa or more. Although the upper limit in particular of the elastic modulus of a particulate-form polymer is not restrict|limited, It is preferable that it is 2000 MPa or less, and it is more preferable that it is 1800 MPa or less. Let the elastic modulus be the value measured by the method demonstrated in the Example mentioned later.

The volume average particle diameter of the particulate polymer is not particularly limited, but is preferably 0.5 µm or less, more preferably 0.4 µm or less, and still more preferably 0.2 µm or less from the viewpoint of binding without coating the sulfide-based inorganic solid electrolyte. Although the lower limit in particular of a volume average particle diameter is not restrict|limited, Actually, it is 0.005 micrometer or more, 0.01 micrometer or more is preferable, and 0.015 micrometer or more is more preferable.

The volume average particle diameter of the particulate polymer can be adjusted, for example, according to the kind of dispersion medium used when preparing the dispersion liquid of the particulate polymer, the content of constituent components in the particulate polymer, and the like.

The volume average particle diameter of the particulate polymer in the constituent layer of the all-solid secondary battery is, for example, measured in advance by disassembling the battery and peeling the constituent layer containing the particulate polymer, then measuring the constituent layer It can measure by excluding the measured value of the volume average particle diameter of particle|grains other than a particulate-form polymer.

The volume average particle diameter of the particulate polymer is a value obtained by the measurement method described in the section of the Examples below.

The volume average particle diameter Ba of the particulate polymer and the volume average particle diameter SEa of the sulfide-based inorganic solid electrolyte preferably satisfy (adjust) the relationship defined by the following formula (I).

By satisfying the relationship of the following volume average particle diameters, ion conduction between sulfide-based inorganic solid electrolytes is not inhibited, and resistance increase is suppressed by binding between sulfide-based inorganic solid electrolytes. It is considered that characteristics such as low resistance are exhibited by following expansion and contraction.

From the viewpoint of the above effect, the volume average particle diameter Ba and the volume average particle diameter SEa preferably satisfy the relationship defined by the following formula (IA), and more preferably satisfy the relationship defined by the following formula (IB).

Ba<SEa<20Ba Formula (I)

Ba<SEa≤15Ba Formula (IA)

Ba<SEa≤10Ba Formula (IB)

(active material)

When using the sheet for all-solid-state secondary batteries obtained by the manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention as an electrode active material layer, an active material is used in the said process (2). As an active material, although demonstrated below, (i) a positive electrode active material and (ii) a negative electrode active material are mentioned.

(i) positive electrode active material

The positive electrode active material is preferably capable of reversibly intercalating and deintercalating lithium ions. The material is not particularly limited as long as it has the above characteristics, and may be a transition metal oxide or an element capable of complexing with Li such as sulfur.

Among them, it is preferable to use a transition metal oxide as the positive electrode active material, and a transition metal oxide having a transition metal element M ^a (at least one element selected from Co, Ni, Fe, Mn, Cu and V) is more preferable. Further, in this transition metal oxide, an element M ^b (element of group 1 (Ia) of the periodic table of metals other than lithium, element of group 2 (IIa), Al, Ga, In, Ge, Sn, Pb, Sb, Bi) , Si, elements such as P and B) may be mixed. As the mixing amount, it is preferably 0 ~ 30mol% relative to the amount of transition metal element M ^a (100mol%). It is more preferable to mix and synthesize so that the molar ratio of Li/M ^{a may be 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, and (MD) a lithium-containing transition metal halide. and rosenated phosphoric acid compounds and (ME) lithium-containing transition metal silicic acid compounds.

(MA) Specific examples of the transition metal oxide having a layered rock salt structure, LiCoO ₂ (lithium cobaltate [LCO]), LiNi ₂ O ₂ (lithium nickelate), LiNi _0.85 Co _0.10 Al _0.05 O ₂ (nickel cobalt aluminum lithium acid [NCA]), LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (lithium nickel manganese cobaltate [NMC]), and LiNi _0.5 Mn _0.5 O ₂ (lithium manganese nickelate). .

(MB) Specific examples of the transition metal oxide having a spinel structure, LiMn ₂ O ₄ (LMO), LiCoMnO ₄ , Li ₂ FeMn ₃ O ₈ , Li ₂ CuMn ₃ O ₈ , Li ₂ CrMn ₃ O ₈ and Li ₂ NiMn ₃ O ₈ .

(MC) Examples of the lithium-containing transition metal phosphate compound include olivine-type iron phosphate salts such as _{LiFePO 4} and Li ₃ Fe ₂ (PO ₄ ) _{3 , iron pyrophosphates such as LiFeP 2} O ₇ , and phosphoric acid such as _{LiCoPO 4 .} and monoclinic NASICON-type vanadium phosphate salts such as cobalts and Li ₃ V ₂ (PO ₄ ) _{3 (lithium vanadium phosphate).}

(MD) as the lithium-containing transition halogenated phosphate compound to metal, for example, Li ₂ FePO ₄ F such as hydrofluoric acid iron salt, Li ₂ MnPO ₄ F such as hydrofluoric acid manganese salt and Li ₂ CoPO ₄ F such as fluoride of and cobalt phosphate.

(ME) as the lithium-containing transition metal silicate compound, for example, there may be mentioned _{Li 2 FeSiO 4, Li 2 MnSiO} 4, Li 2 CoSiO 4.

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

Although the shape in particular of a positive electrode active material is not restrict|limited, A particulate form is preferable. The particle diameter (volume average particle diameter) of a positive electrode active material in particular is not restrict|limited. For example, it can be set as 0.1-50 micrometers.

The measurement of the particle diameter of a positive electrode active material is performed by the following procedure. The positive electrode active material particles are prepared by diluting a 1 mass % dispersion in a 20 mL sample bottle using water (heptane in the case of a water unstable substance). The dispersion liquid sample after dilution is irradiated with 1 kHz ultrasonic wave for 10 minutes, and is used for a test immediately after that. Using this dispersion liquid sample, using a laser diffraction/scattering particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA), the data was read 50 times using a quartz cell for measurement at a temperature of 25°C, and the volume average particle diameter get For other detailed conditions, etc., if necessary, refer to the description of JIS Z 8828:2013 "Particle diameter analysis-dynamic light scattering method". 5 samples per level are produced and the average value is adopted.

In order to make the positive electrode active material into a predetermined particle diameter, a normal grinder or classifier is used. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill or a sieve, etc. are used suitably. At the time of pulverization, wet pulverization in which an organic solvent such as water or methanol is coexisted can also be performed. In order to set it as a desired particle diameter, it is preferable to classify. The classification is not particularly limited, and can be performed using a sieve, a wind classifier, or the like. Classification can be used both dry and wet.

You may use the positive electrode active material obtained by the baking method, after washing|cleaning with water, acidic aqueous solution, alkaline aqueous solution, and an organic solvent.

A positive electrode active material may mix 1 type and may mix 2 or more types.

When forming the positive electrode active material layer, the mass (mg) (weight per unit area) of the positive electrode active material per ^{unit area (cm 2 ) of the positive electrode active material layer is not particularly limited.} According to the designed battery capacity, it can be appropriately determined, for example, 1-100 mg/cm ² It can be set as.

The content in particular of the positive electrode active material in the positive electrode active material layer is not limited, and in 100 mass % of solid content, 10-97 mass % is preferable, 30-95 mass % is more preferable, 40-93 mass % is more It is preferable, 50-90 mass % is more preferable, 60-80 mass % is still more preferable.

(ii) negative electrode active material

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

The carbonaceous material used as the negative electrode active material is a material substantially composed of carbon. For example, petroleum pitch, carbon black such as acetylene black (AB), graphite (artificial graphite such as natural graphite, vapor phase growth graphite, etc.), and PAN (polyacrylonitrile) resin or fur The carbonaceous material which baked various synthetic resins, such as a furyl alcohol resin, is mentioned. In addition, various carbon fibers such as PAN-based carbon fibers, cellulosic 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, flat graphite, and the like can also be mentioned.

These carbonaceous materials can also be divided into non-graphitizable carbonaceous materials (also referred to as hard carbon) and graphite-based carbonaceous materials according to the degree of graphitization. Further, the carbonaceous material preferably has an interplanar spacing or density and crystallite size described in Japanese Patent Application Laid-Open Nos. 62-22066, Hei-2-6856, and 3-45473. The carbonaceous material does not need to be a single material, and a mixture of natural graphite and artificial graphite described in Japanese Patent Application Laid-Open No. Hei 5-90844, graphite having a coating layer described in Japanese Patent Application Laid-Open No. Hei6-4516, etc. may be used. may be

As the carbonaceous material, hard carbon or graphite is preferably used, and graphite is more preferably used.

The oxide of a metal or metalloid element applied as the negative electrode active material is not particularly limited as long as it is an oxide capable of occluding and releasing lithium, and an oxide of a metal element (metal oxide), a composite oxide of a metal element, or a composite of a metal element and a metalloid element oxides (collectively referred to as metal composite oxides) and oxides of semimetal elements (semimetal oxides) are mentioned. As these oxides, an amorphous oxide is preferable, and a chalcogenide which is a reaction product of a metal element and the element of Group 16 of the periodic table is also preferably mentioned. In the present invention, the semimetal element refers to an element exhibiting properties intermediate between a metallic element and a non-metallic element, and usually includes six elements of boron, silicon, germanium, arsenic, antimony and tellurium, and further contains the three elements selenium, polonium and astatine. In addition, amorphous means having a wide scattering band which has a peak in a region of 20° to 40° in 2θ value by an X-ray diffraction method using CuKα rays, and may have a crystalline diffraction line. It is preferable that the strongest intensity among the crystalline diffraction lines seen at 40° to 70° at the 2θ value is 100 times or less, and 5 times or less, the intensity of the diffraction line at the peak of the broad scattering band seen at 20° to 40° at the 2θ value. It is more preferable, and it is especially preferable that it does not have a crystalline diffraction line.

Among the compound group consisting of the amorphous oxide and the chalcogenide, an amorphous oxide of a semimetal element or the chalcogenide is more preferable, and an element of groups 13 (IIIB) to 15 (VB) of the periodic table (eg, Al , Ga, Si, Sn, Ge, Pb, Sb and Bi) alone or a (composite) oxide or chalcogenide composed of a combination of two or more thereof is particularly preferable. Specific examples of preferred amorphous oxides and chalcogenides include, for example, Ga ₂ O ₃ , GeO, PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₂ O ₄ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₈ Bi ₂ O ₃ , Sb ₂ O ₈ Si ₂ O ₃ , Sb ₂ O ₅ , Bi ₂ O ₃ , Bi ₂ O ₄ , GeS, PbS, PbS ₂ , Sb ₂ S ₃ or Sb ₂ S ₅ is preferably mentioned.

Examples of the negative electrode active material that can be used together with the amorphous oxide centered on Sn, Si, and Ge include a carbonaceous material capable of occluding and/or releasing lithium ions or lithium metal, a lithium simple substance, a lithium alloy, a negative electrode active material capable of alloying with lithium can be suitably cited.

Oxides of metals or semimetal elements, particularly metal (composite) oxides and chalcogenides, preferably contain, as constituent components, at least one of titanium and lithium from the viewpoint of high current density charge/discharge characteristics. As the metal composite oxide (lithium composite metal oxide) containing lithium, for example, a composite oxide of lithium oxide and the metal (composite) oxide or the chalcogenide, more specifically, Li ₂ SnO ₂ . .

As for the negative electrode active material, for example, a metal oxide, the thing containing a titanium element (titanium oxide) is also mentioned preferably. Specifically, Li ₄ Ti ₅ O ₁₂ (lithium titanate [LTO]) has excellent rapid charge/discharge characteristics in that the volume fluctuation during intercalation and release of lithium ions is small, and deterioration of the electrode is suppressed to prevent lithium ion secondary batteries. It is preferable in that the lifespan of the improvement becomes possible.

As a lithium alloy as a negative electrode active material, if it is an alloy normally used as a negative electrode active material of a secondary battery, it will not restrict|limit, For example, a lithium aluminum alloy is mentioned.

The negative electrode active material capable of forming an alloy with lithium is not particularly limited as long as it is normally used as a negative electrode active material of a secondary battery. Such an active material exhibits large expansion and contraction due to charging and discharging, and as described above, the binding property of the solid particles decreases, but in the present invention, high binding property can be achieved by the step (3). Examples of such an active material include a negative electrode active material (alloy) having a silicon element or a tin element, and each metal such as Al and In, and a negative electrode active material having a silicon element that enables higher battery capacity (a silicon element-containing active material) This is preferable, and a silicon element-containing active material having a content of elemental silicon of 50 mol% or more of all constituent elements is more preferable.

In general, a negative electrode containing these negative electrode active materials (Si negative electrode containing a silicon element-containing active material, Sn negative electrode containing an active material containing tin element, etc.) has more Li than a carbon negative electrode (graphite and acetylene black, etc.) ions can be occluded. That is, the occlusion amount of Li ions per unit mass increases. Therefore, the battery capacity can be increased. As a result, there is an advantage that the battery driving time can be lengthened.

As the silicon element-containing active material, for example, a silicon material such as Si and SiOx (0<x≤1), and further, a silicon-containing alloy containing titanium, vanadium, chromium, manganese, nickel, copper, lanthanum, etc. (For example, LaSi ₂ , VSi ₂ , La-Si, Gd-Si, Ni-Si), or a structured active material (for example, LaSi ₂ /Si), in addition to silicon such as _{SnSiO 3} , SnSiS ₃ The active material containing an element and a tin element, etc. are mentioned. In addition, since SiOx itself can be used as a negative electrode active material (semimetal oxide), and Si is produced by operation of an all-solid-state secondary battery, it can be used as a negative electrode active material (its precursor material) that can be alloyed with lithium. have.

As the negative electrode active material having a tin element, for example, Sn, SnO, SnO _2, SnS, SnS _2, and further may include an active material such as the silicon element and containing tin element. The composite oxide with lithium oxide, for example, may be mentioned Li ₂ SnO _2.

In the present invention, the above-described negative electrode active material can be used without particular limitation, but in terms of battery capacity, as the negative electrode active material, a negative electrode active material capable of alloying with lithium is a preferred embodiment, and among them, a silicon element-containing active material or a tin element. A negative electrode active material is preferable, and it is more preferable that silicon (Si) or a silicon-containing alloy is included.

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 as an inductively coupled plasma (ICP) emission spectroscopy method as a measuring method and as a simple method.

Although the shape in particular of a negative electrode active material is not restrict|limited, A particulate form is preferable. Although the volume average particle diameter in particular of a negative electrode active material is not restrict|limited, 0.1-60 micrometers is preferable. The volume average particle diameter of the negative electrode active material particles can be measured in the same manner as the average particle diameter of the positive electrode active material. In order to set it as a predetermined particle diameter, similarly to a positive electrode active material, a normal grinder or classifier is used.

The said negative electrode active material may mix 1 type and may mix 2 or more types.

The mass (mg) (weight per unit area) of the negative electrode active material per unit area (cm ^{2 ) of the negative electrode active material layer is not particularly limited.} According to the designed battery capacity, it can be appropriately determined, for example, it can be set as ^{1-100 mg/cm<2>.}

The content of the negative electrode active material in the negative electrode active material layer is not particularly limited, and the solid content is 100% by mass, preferably 10 to 90% by mass, more preferably 20 to 85% by mass, and 30 to 80% by mass It is more preferable, it is more preferable that it is 40-75 mass %, It is more preferable that it is 40-65 mass %.

In the all-solid-state secondary battery of the present invention, when the negative electrode active material layer is formed by charging the secondary battery, instead of the negative electrode active material, ions of a metal belonging to Group 1 or Group 2 of the periodic table generated in the all-solid-state secondary battery is available. A negative electrode active material layer can be formed by combining this ion with an electron and making it precipitate as a metal.

-Coating of active material-

The surface of the positive electrode active material and the negative electrode active material may be surface-coated with another metal oxide. As a surface coating material, the metal oxide containing Ti, Nb, Ta, W, Zr, Al, Si, or Li, etc. are mentioned. Specifically, a spinel titanate, a tantalum-based oxide, a niobium-based oxide, a lithium niobate-based compound, etc. may be mentioned, and specifically, Li ₄ Ti ₅ O ₁₂ , Li ₂ Ti ₂ O ₅ , LiTaO ₃ , LiNbO ₃ , LiAlO ₂ , Li ₂ ZrO ₃ , Li ₂ WO ₄ , Li ₂ TiO ₃ , Li ₂ B ₄ O ₇ , Li ₃ PO ₄ , Li ₂ MoO ₄ , Li ₃ BO ₃ , LiBO ₂ , Li ₂ CO ₃ , Li ₂ SiO ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ , B ₂ O ₃ and the like.

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

In addition, the surface of the particle|grain surface of a positive electrode active material or a negative electrode active material may be surface-treated with actinic ray or an active gas (plasma etc.) before and behind the said surface coating.

(challenge preparation)

In the step (2), a conductive aid may be used, and in particular, the active material containing elemental tin or the active material containing elemental silicon as the negative electrode active material is preferably used in combination with the conductive aid.

There is no restriction|limiting in particular as a conductive support agent, What is known as a general conductive support agent can be used. For example, electron conductive materials such as graphite such as natural graphite and artificial graphite, carbon black such as acetylene black, Ketjen black, and furnace black, amorphous carbon such as needle coke, vapor-grown carbon fiber or carbon nanotube, etc. A carbonaceous material such as carbon fibers, graphene, or fullerene may be used, a metal powder such as copper or nickel may be used, or a metal fiber may be used, and a conductive polymer such as polyaniline, polypyrrole, polythiophene, polyacetylene, or polyphenylene derivative may be used. .

In this invention, when using an active material and a conductive support agent together, insertion and discharge|release of Li do not occur when a battery is charged/discharged among said conductive support agents, and let the thing which does not function as an active material make it a conductive support agent. Therefore, among the conductive aids, those that can function as an active material in the active material layer when the battery is charged and discharged are classified as active materials other than conductive aids. When a battery is charged and discharged, whether or not it functions as an active material is not unique, but is determined by the combination with an active material.

A conductive support agent may mix 1 type and may mix 2 or more types.

Although the shape in particular of a conductive support agent is not restrict|limited, A particulate form is preferable.

Content in particular in the electrode active material layer of a conductive support agent is not restrict|limited, In 100 mass % of solid content, it is preferable that it is 0.1-15 mass %, 0.5-12 mass % is more preferable, It is 1-10 mass % it is more preferable

(Lithium salt)

In the step (2), a lithium salt (supporting electrolyte) may be used.

As a lithium salt, the lithium salt normally used for this kind of product is preferable, and there is no restriction|limiting in particular, For example, the lithium salt of Paragraph 0082 - 0085 of Unexamined-Japanese-Patent No. 2015-088486 is preferable.

When the sheet for all-solid secondary batteries of the present invention contains a lithium salt, the content of the lithium salt is preferably 0.1 parts by mass or more, more preferably 5 parts by mass or more, with respect to 100 parts by mass of the sulfide-based inorganic solid electrolyte. As an upper limit, 50 mass parts or less are preferable, and 20 mass parts or less are more preferable.

(dispersion medium)

In the step (2), a dispersion medium (dispersion medium) may be used, and each of the above components may be dispersed or dissolved, and it is preferable to disperse the particulate organic component and solid particles. As a dispersion medium, various organic solvents are mentioned, for example. As an organic solvent, each solvent, such as an alcohol compound, an ether compound, an amide compound, an amine compound, a ketone compound, an aromatic compound, an aliphatic compound, a nitrile compound, and an ester compound, is mentioned.

The specific example of each said solvent is shown below.

Examples of the alcohol compound include methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, 2-methyl-2,4-pentanediol, 1,3-butanediol, and 1,4-butanediol.

As the ether compound, alkylene glycol alkyl ether (ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol, dipropylene glycol, propylene glycol monomethyl ether) , diethylene glycol monomethyl ether, triethylene glycol, polyethylene glycol, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ethers), dialkyl ethers (dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, etc.), cyclic ethers (tetrahydrofuran, dioxane (1,2-, 1,3) - and each isomer of 1,4-) etc.) are mentioned.

As the amide compound, for example, N,N-dimethylformamide, N-methyl-2-pyrrolidone, 2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, ε-capro lactam, formamide, N-methylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropanamide, hexamethylphosphoric triamide, and the like.

Examples of the amine compound include triethylamine, diisopropylethylamine, and tributylamine.

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

As an aromatic compound, aromatic hydrocarbon compounds, such as benzene, toluene, and xylene, are mentioned, for example.

Examples of the aliphatic compound include aliphatic hydrocarbon compounds such as hexane, heptane, octane, and decane.

As a nitrile compound, acetonitrile, propionitrile, isobutyronitrile etc. are mentioned, for example.

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

As a non-aqueous dispersion medium, the said aromatic compound, an aliphatic compound, etc. are mentioned.

In this invention, especially, an ether compound, a ketone compound, an aromatic compound, an aliphatic compound, and an ester compound are preferable, and a ketone compound is more preferable.

It is preferable that the boiling point in normal pressure (1 atm) of a dispersion medium is 50 degreeC or more, and, as for the dispersion medium, it is more preferable that it is 70 degreeC or more. It is preferable that it is 250 degrees C or less, and, as for an upper limit, it is more preferable that it is 220 degrees C or less.

The said dispersion medium may mix 1 type and may mix 2 or more types.

In this invention, content in particular of a dispersion medium in the mixture used for this invention is not restrict|limited, It can set suitably. For example, in the mixture used for this invention, 20-99 mass % is preferable, 25-70 mass % is more preferable, 30-60 mass % is especially preferable.

(other additives)

In a process (2), as another component other than each said component, an antifoamer, a leveling agent, a dehydrating agent, antioxidant, etc. can be used suitably. The ionic liquid is contained in order to further improve ionic conductivity, and a well-known thing in particular can be used without restrict|limiting. Moreover, you may use polymers other than the said particulate-form polymer, a binder normally used, etc.

[Method for producing sheet for all-solid-state secondary battery]

Hereinafter, each process included in the preferable manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention is demonstrated.

<Process (1)>

In this step, a sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 µm or less can be obtained by, for example, adjusting the mechanical milling time of the sulfide-based inorganic solid electrolyte. In addition, to the sulfide-based inorganic solid electrolyte, for example, a solvent in which the sulfide-based inorganic solid electrolyte does not deteriorate (a dispersion medium that does not readily react with the sulfide-based inorganic solid electrolyte) is added, and the diameter, rotation speed and time of the grinding media are also adjusted. Adjustment, mechanical milling, and grinding|pulverization can make a volume average particle diameter into 1.0 micrometer or less. As the sulfide-based inorganic solid electrolyte to be used, an available one may be used, and for example, it may be synthesized from raw materials such as _{lithium sulfide (Li 2 S) and phosphorus sulfide described above.}

The volume average particle diameter of the sulfide-based inorganic solid electrolyte can be measured by the method described in the section of Examples below.

The volume average particle diameter of the sulfide-based inorganic solid electrolyte (adjusted in the step (1)) used in the step (2) is preferably 0.8 μm or less, and more preferably 0.7 μm or less in order to reduce the resistance by reducing the voids between the particles. desirable. Although the lower limit in particular of a volume average particle diameter is not restrict|limited, Actually, it is preferable that it is 0.01 micrometer or more, 0.02 micrometer or more is more preferable, 0.05 micrometer or more is more preferable, 0.1 micrometer or more is more preferable, 0.3 micrometer or more more preferably.

By setting the volume average particle diameter of the sulfide-based inorganic solid electrolyte to 1.0 µm, it is possible to reduce the voids between the solid electrolyte particles. When an all-solid-state secondary battery is equipped with the solid electrolyte layer in which the solid electrolyte particle was densely filled, it can make it difficult to generate|occur|produce the short circuit by lithium dendrite. On the other hand, when the all-solid-state secondary battery includes the electrode active material layer in which the solid electrolyte particles are densely filled, ion conductivity can be improved.

<Process (2)>

In the method for producing a sheet for an all-solid secondary battery of the present invention, in the particulate organic component and the sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 µm or less obtained in the above step, the content of the particulate organic component is the sulfide-based inorganic solid A step of mixing is performed so that the content of the total of the electrolyte and the particulate organic component is 15% by mass or less, preferably 10% by mass or less.

In this step, the mixture is usually prepared by mixing the sulfide-based inorganic solid electrolyte and the particulate organic component at the above mixing ratio.

The lower limit of the mixing ratio is not particularly limited as long as it exceeds 0 mass %, for example, it can be 0.1 mass % or more, and 0.5 mass % or more is preferable.

In the step (2), the sulfide-based inorganic solid electrolyte, the particulate organic component, and further suitably the active material, the dispersion medium, the lithium salt, and any other components are mixed with, for example, various mixers commonly used to obtain a mixture (preferably composition, more preferably a slurry containing a dispersion medium) can be obtained.

The active material to be mixed is appropriately selected depending on the shape of the sheet, but the negative electrode active material is preferably an active material containing elemental silicon or elemental tin from the viewpoint of battery capacity.

The mixing method in particular is not restrict|limited, You may mix collectively and you may mix sequentially. Although the environment in particular for mixing is not restrict|limited, Under dry air, under an inert gas, etc. are mentioned.

Although the mixing amount in particular of an active material is not restrict|limited, It is preferable to set in the range same as content in the active material layer mentioned above. Although the mixing amount in particular of a lithium salt is not restrict|limited, It is preferable to set in the range similar to content in the sheet|seat for all-solid-state secondary batteries mentioned above. Although the mixing amount in particular of a dispersion medium is not restrict|limited, It is preferable to set in the range same as content in the above-mentioned mixture. The mixing amount of the other components is appropriately determined.

<Process (3)>

In the method for manufacturing a sheet for an all-solid secondary battery of the present invention, at a temperature 20° C. or more higher than the glass transition temperature of the particulate organic component and lower than the decomposition temperature of the particulate organic component, 1/10 of the elastic modulus of the particulate organic component A step of pressurizing the mixture at a higher pressure is performed.

The heating temperature is preferably 30°C or higher higher than the glass transition temperature of the particulate organic component, more preferably 40°C or higher, and still more preferably 50°C or higher. On the other hand, although the upper limit of the heating temperature may be less than the decomposition temperature, a temperature 10°C or more lower than the decomposition temperature is preferable, and a temperature 20°C or more lower than the decomposition temperature is more preferable.

Further, the pressure is preferably higher than 1/7 of the elastic modulus of the particulate organic component, more preferably higher than 1/6, more preferably higher than 1/5, and more preferably higher than 1/4. and more preferably higher than 1/3. On the other hand, the upper limit of the pressure is not particularly limited, but is usually set to 1500 MPa or less, preferably 1200 MPa or less, and more preferably 1000 MPa or less.

By pressurizing at a heating temperature in the above range, the particulate organic component becomes soft, the binding property with the sulfide-based inorganic solid electrolyte is improved, and ion conduction between the sulfide-based inorganic solid electrolyte is not inhibited, and a strong solid electrolyte layer or It is thought that an electrode active material layer can be formed. Thereby, it is thought that reduction of the resistance of a solid electrolyte layer can be implement|achieved, the formation of voids by volume expansion of an active material in an electrode active material layer can be suppressed, and battery performance can be improved.

The method of pressurizing at the said heating temperature is not restrict|limited in particular, For example, the method using a hot press machine, a hot plate, etc. is mentioned. Pressurization time can be made into 3 to 30 minutes, for example.

In the manufacturing method of the all-solid-state secondary battery of this invention, when the mixture used for this invention contains a dispersion medium, it is preferable to heat-dry the said mixture containing a dispersion medium before the said pressurizing process. Specifically, the mixture (slurry, etc.) is applied to a substrate or on a current collector (another layer may be interposed therebetween), the dispersion medium is dried to obtain a solid state (application dried layer), and then Pressurized in a temperature range.

The method for applying the mixture is not particularly limited and may be appropriately selected. For example, application|coating (preferably wet application|coating), spray application|coating, spin coat application|coating, dip coat application|coating, slit application|coating, stripe application|coating, and bar coat application|coating are mentioned.

When the mixture includes a dispersion medium, the drying temperature of the dispersion medium is not particularly limited. The lower limit is preferably 30°C or higher, more preferably 60°C or higher, and still more preferably 80°C or higher. 300 degrees C or less is preferable, as for an upper limit, 250 degrees C or less is more preferable, and 200 degrees C or less is still more preferable.

In the present invention, it is preferable not to completely remove the dispersion medium in the drying step after application of the slurry. Specifically, it is preferable to heat the obtained mixture so that the dispersion medium is not completely removed to pressurize the obtained coating dried layer.

The residual amount of the dispersion medium in the coating dry layer at this time is not particularly limited, but it is preferably 10 to 2000 ppm, more preferably 10 to 1500 ppm, more preferably 10 to 1000 ppm, still more preferably 10 to 500 ppm, , It is especially preferable that it is 10-200 ppm. By carrying out the said process (3) in the state which has not removed the dispersion medium completely, binding property between solid particles can be improved more.

As described above, the applied dry layer in which the dispersion medium remained is pressurized. When the sheet having the applied dry layer and the substrate or current collector is pressed using a hot plate or a hot press machine, the sheet is placed on the hot plate with the substrate or the current collector in contact with the hot plate, and the dispersion medium is applied on the hot plate. You may dry it to form an application|coating dry layer, and you may press with a hot press machine. The heating time in this case can be made into 1 to 30 minutes, for example, and the pressurization time can be made into 1 to 30 minutes, for example. In addition, it is preferable to pressurize the hot press machine by setting it to the same temperature as the heating temperature of a hotplate in advance.

By the manufacturing method of the all-solid-state secondary battery sheet of this invention, it is an all-solid-state secondary battery sheet excellent in binding property, and by using it as a structural layer of an all-solid-state secondary battery, an all-solid-state secondary battery which shows excellent battery characteristics can be implement|achieved. Although the reason is not certain, it is estimated as follows.

When the mixture used in the present invention contains the particulate organic component in an amount of 15% by mass or less of the total content of the sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 μm or less and the particulate organic component, the mixture contains a dispersion medium Even in the state, the dispersion medium appropriately softens the particulate organic component and improves the contact between the sulfide-based inorganic solid electrolyte, so it is thought that aggregation of solid particles can be suppressed. Further, it is thought that, by using this mixture, a sheet having improved binding property between solid particles by suppressing decomposition of the particulate organic component and imparting flexibility to the particulate organic component by the above-mentioned pressing step can be obtained. By improving the binding property between the solid particles containing the sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 μm or less, short circuit can be suppressed, and the formation of voids generated during expansion and contraction of the active material can be suppressed. , it is considered that the cycle characteristics and rate characteristics of the all-solid-state secondary battery can be improved.

[Method for manufacturing all-solid-state secondary battery]

The manufacturing method of the all-solid-state secondary battery of this invention is manufactured by a normal method except for attaching the sheet for all-solid-state secondary batteries obtained by the manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention as at least one layer among the structural layers. can do. Thereby, the all-solid-state secondary battery which shows excellent battery performance can be manufactured. Hereinafter, it demonstrates in detail.

For example, on the metal foil which is a positive electrode current collector, as a material for positive electrodes (composition for positive electrode layer), a normal solid electrolyte composition containing a positive electrode active material is apply|coated, a positive electrode active material layer is formed, and a positive electrode sheet is produced. Next, on this positive electrode active material layer, the sheet|seat for solid electrolyte layers (solid electrolyte layer) obtained by the manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention is superposed. Moreover, on the solid electrolyte layer, as a material for negative electrodes (composition for negative electrode layers), a normal solid electrolyte composition containing a negative electrode active material is apply|coated, and a negative electrode active material layer is formed. By superposing a negative electrode current collector (metal foil) on the negative electrode active material layer, an all-solid-state secondary battery having a structure in which a solid electrolyte layer is sandwiched between the positive electrode active material layer and the negative electrode active material layer can be obtained. This can also be enclosed in a case and it can also be set as a desired all-solid-state secondary battery.

In addition, by reversing the formation method of each layer, the negative electrode active material layer, the solid electrolyte layer and the positive electrode active material layer are formed on the negative electrode current collector, and the positive electrode current collector is overlapped to produce an all-solid-state secondary battery. .

As another method, the following method is mentioned. That is, according to the manufacturing method of the sheet for an all-solid-state secondary battery of the present invention, a positive electrode sheet having a positive electrode active material layer on a current collector, a solid electrolyte layer sheet having a solid electrolyte layer on a substrate, and a negative electrode active material layer on the current collector A negative electrode sheet having a On the active material layer of either one of the positive electrode sheet and the negative electrode sheet, the sheet for a solid electrolyte layer is overlapped so that the active material layer and the solid electrolyte layer are in contact. After peeling a base material, on the solid electrolyte layer, the other of a positive electrode sheet and a negative electrode sheet is laminated|stacked so that a solid electrolyte layer and an active material layer may contact. In this way, an all-solid-state secondary battery can be manufactured.

As another method, the following method is mentioned. That is, according to the manufacturing method of the sheet for an all-solid-state secondary battery of the present invention, a positive electrode sheet having a positive electrode active material layer on a current collector, a solid electrolyte layer sheet having a solid electrolyte layer on a substrate, and a negative electrode active material layer on the current collector A negative electrode sheet having a Moreover, it laminates|stacks so that the solid electrolyte layer peeled from a base material may be pinched|interposed between a positive electrode sheet and a negative electrode sheet. In this way, an all-solid-state secondary battery can be manufactured.

After producing the all-solid-state secondary battery, it is preferable to pressurize the all-solid-state secondary battery. Moreover, it is also preferable to pressurize in the state which laminated|stacked each layer. As a pressurization method, a hydraulic cylinder hot press machine etc. are mentioned. It does not restrict|limit especially as a pressing force, Generally, it is preferable that it is the range of 5-1500 MPa.

The atmosphere during pressurization is not particularly limited, and may be any of atmospheric conditions, dry air (dew point -20°C or less), and inert gas (eg, argon gas, helium gas, nitrogen gas).

For the press time, high pressure may be applied for a short time (eg, within several hours), or medium pressure may be applied for a long time (one day or more). In addition to the all-solid-state secondary battery sheet, for example, in the case of an all-solid-state secondary battery, in order to continue to apply a medium pressure, a restraint tool (screw clamping pressure, etc.) of the all-solid-state secondary battery may be used.

The press pressure may be uniform with respect to a portion to be pressed such as a sheet surface, or may be different pressures.

The press pressure can be changed according to the area or film thickness of the part to be pressed. It is also possible to change the same area to different pressures step by step.

The press surface may be smooth or may be roughened.

[Sheet for all-solid-state secondary batteries]

The sheet for all-solid-state secondary batteries manufactured by the manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention has a layer obtained by press-molding the mixture used for this invention. The layer of this sheet contains a sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 µm or less and a particulate organic component, contains an active material depending on the shape of the sheet, and appropriately contains a conductive aid and other components. do. In this layer, the details of the presence state of the sulfide-based inorganic solid electrolyte and the particulate organic component are not clear, but the state in which they are bound as described above is mentioned.

The sheet for an all-solid-state secondary battery of the present invention is a sheet-like molded body capable of forming a constituent layer of an all-solid-state secondary battery, and includes various aspects depending on the use thereof.

The sheet for a solid electrolyte layer of the present invention may be a sheet having a solid electrolyte layer, may be a sheet in which a solid electrolyte layer is formed on a substrate, or may be a sheet in which a solid electrolyte layer is formed without a substrate. The sheet for solid electrolyte layers may have other layers other than the solid electrolyte layer. As another layer, a protective layer (release sheet), an electrical power collector, a coating layer, etc. are mentioned, for example.

Examples of the sheet for a solid electrolyte layer of the present invention include a sheet having, on a substrate, a solid electrolyte layer and a protective layer in this order.

The base material is not particularly limited as long as it can support the solid electrolyte layer, and examples of the material described in the current collector described below include sheet bodies (plate bodies) such as organic materials and inorganic materials. As an organic material, various polymers etc. are mentioned, Specifically, a polyethylene terephthalate, a polypropylene, polyethylene, a cellulose, etc. are mentioned. As an inorganic material, glass, a ceramic, etc. are mentioned, for example.

The structure and layer thickness of the solid electrolyte layer of the sheet for all-solid-state secondary batteries are the same as the structure and layer thickness of the solid electrolyte layer demonstrated in the all-solid-state secondary battery of this invention.

The electrode sheet of the present invention may be an electrode sheet having an active material layer, may be a sheet in which an active material layer is formed on a base material (current collector), or may be a sheet in which an active material layer is formed without a base material. This electrode sheet is usually a sheet having a current collector and an active material layer, but an embodiment having a current collector, an active material layer, and a solid electrolyte layer in this order, and a current collector, an active material layer, a solid electrolyte layer and an active material layer in this order Also included are aspects with The electrode sheet of this invention may have the other layer mentioned above. The layer thickness of each layer which comprises the electrode sheet of this invention is the same as the layer thickness of each layer demonstrated in the all-solid-state secondary battery mentioned later.

In the all-solid-state secondary battery sheet of the present invention, at least one of the solid electrolyte layer and the active material layer is produced by the method for manufacturing the all-solid-state secondary battery sheet of the present invention, and solid particles in this layer are firmly bound to each other. . Moreover, in the electrode sheet, the active material layer produced by the manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention is also strongly binding|bonded with the electrical power collector. In this invention, the raise of the interface resistance between solid particles can also be suppressed effectively. Therefore, the sheet|seat for all-solid-state secondary batteries of this invention is used suitably as a sheet|seat which can form the structural layer of an all-solid-state secondary battery.

When an all-solid-state secondary battery is manufactured using the sheet for all-solid-state secondary batteries of this invention, it shows the outstanding battery performance.

[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 preferably formed on the positive electrode current collector to constitute the positive electrode. The negative electrode active material layer is preferably formed on the negative electrode current collector to constitute the negative electrode.

At least one layer of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer is produced by the method for manufacturing the sheet for an all-solid-state secondary battery of the present invention, and all layers are produced by the method for manufacturing the sheet for an all-solid-state secondary battery of the present invention more preferably. In addition, when an active material layer or a solid electrolyte layer is not produced by the manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention, a normal active material layer or solid electrolyte layer can be used.

Each of the thickness of the negative electrode active material layer, the solid electrolyte layer, and the positive electrode active material layer is not particularly limited. When the dimension of a general all-solid-state secondary battery is considered, 10-1,000 micrometers is preferable, respectively, and, as for the thickness of each layer, 20 micrometers or more and less than 500 micrometers are more preferable. In the all-solid-state secondary battery of this invention, it is more preferable that the thickness of at least 1 layer among a positive electrode active material layer and a negative electrode active material layer is 50 micrometers or more and less than 500 micrometers.

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

〔case〕

The all-solid-state secondary battery of the present invention may be used as an all-solid-state secondary battery in the state of the above structure depending on the application. However, in order to form a dry cell, it is preferable to use it enclosed in a more suitable case. The case may be a metallic thing or a resin (plastic) thing may be sufficient as it. When a metallic thing is used, the thing made from an aluminum alloy or stainless steel is mentioned, for example. The metallic case is preferably divided into a case on the positive electrode side and a case on the negative electrode side, and electrically connected to the positive electrode current collector and the negative electrode current collector, respectively. It is preferable that the case on the positive electrode side and the case on the negative electrode side are joined together through a gasket for preventing a short circuit to be integrated.

Hereinafter, an all-solid-state 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.

1 is a cross-sectional view schematically illustrating an all-solid-state 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 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, a positive electrode current collector ( 5) in this order. Each layer is in contact with each other and has an adjacent structure. By employing such a structure, electrons (e ⁻ ) are supplied to the negative electrode side during charging, and lithium ions (Li ⁺ ) are accumulated there. On the other hand, during discharge, lithium ions (Li ⁺ ) accumulated in the negative electrode are returned to the positive electrode side, and electrons are supplied to the operation site 6 . In the illustrated example, a light bulb is modeled for the actuating part 6, and it is made to light by discharge.

When an all-solid-state secondary battery having the layer configuration shown in Fig. 1 is put in a 2032-type coin case, this all-solid-state secondary battery is called a laminate for all-solid-state secondary batteries, and this all-solid-state secondary battery laminate is put into a 2032-type coin case The manufactured battery is sometimes called an all-solid-state secondary battery and is called separately.

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

In the all-solid-state secondary battery 10, the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer are all produced by the manufacturing method of the all-solid-state secondary battery sheet of the present invention. This all-solid-state secondary battery 10 exhibits excellent battery performance. The sulfide-based inorganic solid electrolyte and particulate organic component 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 or different from each other.

In the present invention, any one or both of the positive electrode active material layer and the negative electrode active material layer is simply referred to as an active material layer or an electrode active material layer in some cases. Moreover, any one or both of a positive electrode active material and a negative electrode active material may be put together and simply called an active material or an electrode active material.

In the all-solid-state secondary battery 10, the negative electrode active material layer can be a lithium metal layer. Examples of the lithium metal layer include a layer formed by depositing or molding lithium metal powder, a lithium foil, a lithium vapor deposition film, and the like. The thickness of the lithium metal layer may be, for example, 1 to 500 µm regardless of the thickness of the negative electrode active material layer.

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

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

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

As a material for forming the negative electrode current collector, in addition to aluminum, copper, copper alloy, stainless steel, nickel and titanium, etc., it is preferable that the surface of aluminum, copper, copper alloy or stainless steel is treated with carbon, nickel, titanium or silver, Aluminum, copper, copper alloys and stainless steel are more preferred.

As the shape of the current collector, a film sheet-like one is usually used, but a net, a punched one, a lath body, a porous body, a foam body, a molded body of a fiber group, and the like can also be used.

Although the thickness in particular of an electrical power collector is not restrict|limited, 1-500 micrometers is preferable. Moreover, it is also preferable that the surface of an electrical power collector forms unevenness|corrugation by surface treatment.

In the present invention, functional layers, members, etc. may be appropriately interposed or disposed between or outside each layer 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. Moreover, each layer may be comprised by a single layer, and may be comprised by multiple layers.

<Initialization of all-solid-state secondary battery>

It is preferable that the all-solid-state secondary battery manufactured as mentioned above performs initialization after manufacture or before use. Initialization is not particularly limited, and can be performed, for example, by first charging and discharging in a state in which the press pressure is raised, and then releasing the pressure until it reaches the general operating pressure of the all-solid-state secondary battery.

[Use of all-solid-state secondary battery]

The all-solid-state secondary battery of the present invention can be applied to various uses. Although there is no particular limitation on the application mode, for example, when mounted on an electronic device, a notebook computer, a pen input computer, a mobile computer, an electronic book player, a mobile phone, a cordless phone, a wireless pager, a portable communication terminal , portable fax machines, portable copiers, portable printers, headphone stereos, video movies, LCD televisions, handy cleaners, portable CDs, mini disks, electric shavers, transceivers, electronic notebooks, calculators, memory cards, portable tape recorders, radios, backup power supplies, etc. can be heard Examples of other consumer products include automobiles, electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, watches, strobes, cameras, medical equipment (pace makers, hearing aids, shoulder massagers, etc.). In addition, it can be used for various military uses and space applications. Moreover, it can also be combined with a solar cell.

Example

Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is limited by this and is not interpreted. In the following examples, "parts" and "%" indicating the composition are based on mass unless otherwise specified. In the present invention, "room temperature" means 25 ℃.

<Synthesis of sulfide-based inorganic solid electrolyte>

As a sulfide-based inorganic solid electrolyte, T. Ohtomo, A. Hayashi, M. Tatsumisago, Y. Tsuchida, S. Hama, K. Kawamoto, Journal of Power Sources, 233, (2013), pp 231-235 and A. Hayashi , S. Hama, H. Morimoto, M. Tatsumisago, T. Minami, Chem. Lett., (2001), pp 872-873, referring to non-patent literature, a Li-P-S-based glass was synthesized.

Specifically, in a glove box under an argon atmosphere (dew point -70°C) _{, 2.42 g of lithium sulfide (Li 2} S, manufactured by Aldrich, purity >99.98%) and diphosphorus pentasulfide (P ₂ S ₅ , manufactured by Aldrich, purity) >99%) 3.90 g were each weighed, put into an agate mortar, and mixed for 5 minutes using an agate pestle. The mixing ratio of Li ₂ S and P ₂ S _{5 was Li 2} S:P ₂ S ₅ =75:25 in molar ratio.

In a 45 mL container made of zirconia (manufactured by Fritz), 66 g of zirconia beads having a diameter of 5 mm were put, the total amount of the mixture of lithium sulfide and diphosphorus pentasulfide described above, and the container was sealed in an argon atmosphere. The container was set in a planetary ball mill P-7 (trade name, manufactured by Fritz Corporation), and mechanical milling was performed at a temperature of 25° C. at a rotation speed of 510 rpm for 20 hours, thereby forming a yellow powdery sulfide-based inorganic solid electrolyte (hereinafter referred to as “LPS”). It is indicated.) 6.10 g was obtained. The volume average particle diameter (SEa) of this LPS was 0.8 micrometer.

LPS other than the LPS described in Tables 1 to 3 below were synthesized in the same manner as described above. In addition, SEa was adjusted by adjusting the time for performing mechanical milling.

(Method of measuring SEa)

Said SEa was measured as follows.

A 1 mass % dispersion liquid was prepared by diluting the said LPS in a 20 mL sample bottle using heptane. The dispersion liquid sample after dilution was irradiated with 1 kHz ultrasonic wave for 10 minutes, and was used for the test immediately after that. Using this dispersion liquid sample, using a laser diffraction/scattering particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA), the data was read 50 times using a quartz cell for measurement at a temperature of 25°C, and the volume average particle diameter got For other detailed conditions, etc., as necessary, reference was made to the description of JIS Z 8828:2013 "Particle diameter analysis-dynamic light scattering method". Five samples per level were prepared and the average value was adopted.

<Synthesis of particulate organic component (particulate polymer)>

(Preparation of acrylic latex 1)

115 g of toluene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was poured into a 300 mL three-necked flask equipped with a reflux cooling tube and a gas introduction cock, and nitrogen gas was introduced at a flow rate of 200 mL/min for 10 minutes, and then the temperature was raised to 95°C. 25.7 g of ethyl methacrylate (manufactured by Fujifilm Wako Junyaku), 51.8 g of dodecyl methacrylate (manufactured by Fujifilm Wako Junyaku), 0.8 g of acrylic acid (manufactured by FUJIFILM Wako Junyaku), prepared in another container g, V-601 (trade name, oil-soluble azo polymerization initiator, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was mixed with 1.5 g) was added dropwise over 2 hours. 0.8 g of V-601 was added after completion|finish of dripping. Then, after stirring at 95°C for 1 hour, glycidyl methacrylate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) 2.96 g, triethylamine (manufactured by Fujifilm Wako Junyaku Co., Ltd.) 0.29 g, 2,2,6,6-tetramethyl 0.01 g of piperidine 1-oxyl (made by Tokyo Chemical Industry Co., Ltd.) was added, and it stirred at 100 degreeC for 3 hours. After cooling to room temperature, re-precipitating in methanol after dilution with 1 L of toluene, decantation was performed and the macromonomer B-1 was obtained by drying at 80°C.

In a 200 mL three-necked flask, 13.7 g of macromonomer B-1 solution and 20 g of heptane were put, and the temperature was raised to 80° C. while stirring (solution A). Separately, 12.8 g of 2-hydroxyethyl acrylate, 3.0 g of mono(2-acryloyloxyethyl succinate), and 0.61 g of V-601 were added to a 50 mL measuring cylinder, stirred, and uniformly dissolved (solution) B). Solution B was added dropwise to solution A at 80°C for 2 hours, then stirred at 80°C for 2 hours and at 90°C for 2 hours for polymerization, followed by cooling to room temperature. In this way, acrylic latex 1 was obtained. The decomposition temperature of the acrylic polymer in the acrylic latex 1 was 192 degreeC. Moreover, the mass average molecular weight of the acrylic polymer in the acrylic latex 1 was 65,000, and the volume average particle diameter was 120 nm.

(Preparation of urethane latex 1)

To a 200 mL three-neck flask, 1.58 g of 2,4-pentanediol and 1.86 g of NISSO-PB GI-1000 (trade name, manufactured by Nippon Soda Corporation) were added, and dissolved in 80 g of THF (tetrahydrofuran). To this solution, 4.2 g of diphenylmethane diisocyanate was added, stirred at 60°C, and uniformly dissolved. To the obtained solution, 290 mg of Neostan U-600 (trade name, manufactured by Nitto Chemical Co., Ltd.) was added, followed by stirring at 60°C for 6 hours to obtain a viscous polymer solution. Methanol 0.8g was added to this polymer solution, the polymer terminal was sealed, the polymerization reaction was stopped, and the 20 mass % THF solution (polymer solution) of a polymer was obtained.

Next, while stirring the polymer solution obtained above at 350 rpm, 110 g of 2,6-dimethyl-4-heptanone was added dropwise over 1 hour to obtain an emulsion of urethane latex 1. THF was removed by pressure-reducing the emulsion liquid at 40 mPa and 40 degreeC for 1 hour. In this way, urethane latex 1 (solid content 10 mass %) was obtained. The decomposition temperature of the polyurethane in the urethane latex 1 was 230 degreeC. The mass average molecular weight of the polyurethane in the urethane latex 1 was 35,000, and the volume average particle diameter was 80 nm.

The urethane number of the polyurethane in the urethane latex 1 was 4.39 mmol/g. The urethane number was calculated as follows.

Urethane content = urethane binding amount (mmol) of 1 mol of particulate organic component / mass (g) of 1 mol of organic component

The urethane binding amount (mmol) of ¹ mol of the particulate organic component was measured by 1 H-NMR.

(Preparation of urethane latex 2)

To a 200 mL three-neck flask, 0.74 g of 2,4-pentanediol and 13.86 g of NISSO-PB GI-1000 (trade name, manufactured by Nippon Soda Corporation) were added, and dissolved in 80 g of THF (tetrahydrofuran). To this solution, 4.2 g of diphenylmethane diisocyanate was added, stirred at 60°C, and uniformly dissolved. To the obtained solution, 290 mg of Neostan U-600 (trade name, manufactured by Nitto Chemical Co., Ltd.) was added, followed by stirring at 60°C for 6 hours to obtain a viscous polymer solution. Methanol 0.8g was added to this polymer solution, the polymer terminal was sealed, the polymerization reaction was stopped, and the 20 mass % THF solution (polymer solution) of a polymer was obtained.

Next, while stirring the polymer solution obtained above at 350 rpm, 110 g of 2,6-dimethyl-4-heptanone was added dropwise over 1 hour to obtain an emulsion of urethane latex 2. THF was removed by pressure-reducing the emulsion liquid at 40 mPa and 40 degreeC for 1 hour. In this way, urethane latex 2 (solid content 10 mass %) was obtained. The decomposition temperature of the polyurethane in the urethane latex 2 was 230 degreeC. The mass average molecular weight of the polyurethane in the urethane latex 2 was 45,000, and the volume average particle diameter was 30 nm. The urethane number of the polyurethane in the urethane latex 2 was 1.8 mmol/g.

(Preparation of urethane latex 3)

Except for using dicyclohexylmethane diisocyanate (manufactured by Tokyo Chemical Company) instead of diphenylmethane diisocyanate, in the same manner as urethane latex 2, urethane latex 3 (solid content 10% by mass) got The decomposition temperature of the polyurethane in the urethane latex 3 was 220 degreeC. The mass average molecular weight of the polyurethane in the urethane latex 3 was 42,000, and the volume average particle diameter was 70 nm. The urethane number of the polyurethane in the urethane latex 3 was 1.7 mmol/g.

Tg (°C), decomposition temperature (°C), elastic modulus (MPa), and volume average particle diameter (µm) of the synthesized particulate polymer were measured as follows.

(Method for measuring Tg (°C))

The glass transition point was measured under the following conditions using a differential scanning calorimeter (DSC7000, manufactured by SII Technologies) using the dry samples of the acrylic latex 1 and urethane latex 1-3. The dry sample put 10g of synthesized latex liquid on an aluminum pan, heated at 120 degreeC for 2 hours, and after distilling off a solvent, it dried in a vacuum state for 6 hours. The measurement was performed twice with the same sample, and the measurement result of the 2nd time was employ|adopted.

・Atmosphere in the measurement room: nitrogen (60 mL/min)

·Temperature increase rate: 3℃/min

・Measurement start temperature: -100℃

・Measurement end temperature: 200℃

・Sample pan: Aluminum pan

・Mass of measurement sample: 5 mg

Calculation of Tg: Tg was calculated by rounding off the decimal point of the intermediate temperature between the starting point of the descent and the end point of the descent of the DSC chart.

(Measurement of decomposition temperature of particulate polymer)

The acrylic latex 1 and urethane latex 1 to 3 were vacuum dried at a temperature of 120° C. for 2 hours to obtain a particulate polymer. This particulate polymer was subjected to thermal mass differential thermal simultaneous measurement (Tg-DTA) in a nitrogen atmosphere. The mass at the start of the measurement of the particulate polymer was taken as 100%, and the temperature at which the mass decreased by 10% (to 90%) was set as the decomposition temperature.

A differential scanning calorimeter (DSC7000, manufactured by SII Technologies) was used for the simultaneous measurement of thermal mass and differential heat.

(Method for measuring elastic modulus (MPa))

According to JISK7127 (1999), the tensile modulus was measured at 25 degreeC.

The dispersion of the prepared particulate organic component was cast on a Teflon (registered trademark) film to prepare a single film of the particulate polymer having a film thickness of 100 µm. The single film was cut out to 1 cm x 2 cm, and a tensile test (extension between chucks) was performed at 30 mm/min to determine the tensile modulus.

(Method for measuring volume average particle diameter (μm))

In the measurement of SEa, the volume average particle diameter Ba of the particulate organic component was measured in the same manner as in the measurement of SEa, except that the prepared dispersion of the particulate organic component was used instead of the dispersion of LPS.

<Production of sheet S-1 for solid electrolyte layer>

In a dry room with a dew point of -60 degreeC, the solid electrolyte composition was prepared as follows, and the sheet|seat S-1 for solid electrolyte layers was produced using this solid electrolyte composition.

180 zirconia beads having a diameter of 5 mm were put into a 45 mL container made of zirconia (manufactured by Fritz), 4.6 g of LPS having a volume average particle diameter of 0.8 μm synthesized above, an amount of acrylic latex 1 solid content of 0.4 g, and diiso After throwing in 12.0 g of butyl ketone, this container was set in the planetary ball mill P-7 (trade name, manufactured by Fritz), and stirred at a temperature of 25°C and a rotation speed of 350 rpm for 2 hours.

In addition, before and after this process, LPS maintained the volume average particle diameter.

After drying the slurry of the solid electrolyte composition obtained in this way by an applicator (trade name: SA-201 Baker-type applicator, manufactured by Tester Sangyo) on an aluminum foil having a thickness of 20 μm, the slurry was coated to a thickness of 150 μm, and dried at 100° C. for 1 hour, A coating dry layer was formed.

A 500 mg sample was cut out from the coating dry layer, extracted with toluene, and the amount of diisobutyl ketone contained was measured by gas chromatography, and as a result, it contained 100 ppm on a mass basis.

The cut-out portion of the sample was removed, and a rectangular sample having a side of 15 mm was cut out from the applied dry layer, and the sample was pressurized under the following condition 1 to prepare a sheet S-1 for a solid electrolyte layer.

-Condition 1-

It pressurized for 5 minutes at the heating temperature and pressure shown in following Table 1 using the hot press machine (Azone company small hot press machine H300-15 (brand name)).

-Condition 2-

A hot plate was set at the temperature shown in Table 1 below, and a rectangular sample having a side of 15 mm was raised for 15 minutes, and then this sample was pressurized by a hot press at the pressure shown in Table 1 below for 5 minutes.

In the preparation of the sheet S-1 for a solid electrolyte layer, except that the composition and pressurization conditions were changed to the compositions and conditions described in Table 1 below, in the same manner as in the sheet S-1 for a solid electrolyte layer, shown in Table 1 below, Sheets for solid electrolyte layers other than sheet S-1 for solid electrolyte layers were produced.

In addition, preparation of the sheet|seat for solid electrolyte layers which employ|adopted Condition 1 as the conditions of pressurization was performed in a dry room (dew point -60 degreeC). On the other hand, preparation of the sheet for solid electrolyte layers employing Condition 2 as the conditions for pressurization was performed in a glove box (in an Ar atmosphere, dew point -60°C).

The production of a positive electrode sheet and a negative electrode sheet, which will be described later, is also the same.

[Table 1]

[Note of table]

Content of the dispersion medium of the application|coating dry layer which the sheet|seat produced under condition 2 has is content before pressurization after putting on the hotplate of condition 2.

Content of a particulate-form organic component is content of solid content.

<Production of positive electrode sheet SS-1>

Dry room with dew point -60 degreeC WHEREIN: The composition for positive electrodes was prepared as follows, and positive electrode sheet SS-1 was produced using this composition for positive electrodes.

180 zirconia beads with a diameter of 5 mm were put into a 45 mL container made of zirconia (manufactured by Fritz Co., Ltd.), 7.8 g of LPS synthesized above, an amount of acrylic latex 1 solid content of 0.3 g, and 10 g of diisobutyl ketone were added . This vessel was set in a planetary ball mill P-7 (trade name, manufactured by Fritz Corporation), and stirring was continued for 6 hours at a temperature of 25°C and a rotation speed of 350 rpm. In this way, a solid electrolyte composition was prepared.

With respect to 9.1 g of this solid electrolyte composition, 3.5 g of NMC, 0.15 g of acetylene black, and 5 g of diisobutyl ketone were put into a 45 mL zirconia container (manufactured by Fritz) together with 180 zirconia beads having a diameter of 5 mm, and the container was It set in planetary ball mill P-7, and it stirred for 5 minutes at the temperature of 25 degreeC, and rotation speed of 50 rpm, and obtained the composition for positive electrodes.

The slurry for the positive electrode composition thus obtained was applied on an aluminum foil having a thickness of 20 μm with an applicator (trade name: SA-201 Baker Applicator, manufactured by Tester Sangyo Co., Ltd.) so that the mass of the composition for positive electrode after drying was 20 mg per ^{1 cm 2 , 120} It dried at °C for 1 hour to form a coating dry layer.

A 500 mg sample was cut out from the coating dry layer, extracted with toluene, and the amount of diisobutyl ketone contained was measured by gas chromatography, and as a result, it contained 80 ppm on a mass basis.

The cut-out portion of the sample was removed, a rectangular sample having a side of 15 mm was cut out from the applied dry layer, and the sample was pressurized under the condition 1 for 5 minutes to prepare a positive electrode sheet SS-1.

In the production of the sheet having the positive electrode SS-1, positive electrode sheets other than the positive electrode sheet SS-1 shown in Table 1 below were produced, except that the composition and pressurization conditions were changed to the compositions and conditions described in Table 1 below. .

[Table 2]

[Note in table]

NMC: LiNi _1/3 Co _1/3 Mn _1/3 O ₂

Content of the dispersion medium of the application|coating dry layer which the sheet|seat produced under condition 2 has is content before pressurization after putting on the hotplate of condition 2.

Content of a particulate-form organic component is content of solid content.

<Production of negative electrode sheet FS-1>

Dry room with dew point -60 degreeC WHEREIN: The composition for negative electrodes was prepared as follows, and negative electrode sheet FS-1 was produced using this composition for negative electrodes.

180 zirconia beads with a diameter of 5 mm were put into a 45 mL container made of zirconia (manufactured by Fritz), 8.6 g of LPS synthesized above, an amount of acrylic latex 1 solid content of 0.4 g, and 10 g of diisobutyl ketone were added . This vessel was set in a planetary ball mill P-7 (trade name, manufactured by Fritz Corporation), and stirred at a temperature of 25°C and a rotational speed of 350 rpm for 6 hours.

Furthermore, 10.0 g of Si powder (Silicon Powder volume average particle diameter 1-5 micrometers by Alfa Aesar company) and 1.0 g of acetylene black were thrown into the container, and 5 g of diisobutyl ketones were further thrown into it. This container was set in planetary ball mill P-7 (trade name, manufactured by Fritz Corporation), and stirred at a temperature of 25°C and a rotation speed of 100 rpm for 5 minutes to obtain a composition for negative electrodes.

The slurry of the composition for negative electrode obtained in this way was applied on a 20 μm stainless steel foil with an applicator (trade name: SA-201 Baker Applicator, manufactured by Tester Sangyo) so that the mass of the composition for negative electrode after drying was 3.3 ^{mg per 1 cm 2 , and 100} It dried at °C for 1 hour to form a coating dry layer.

A 500 mg sample was cut out from the coating dry layer, extracted with toluene, and the amount of diisobutyl ketone contained was measured by gas chromatography, and as a result, it contained 80 ppm.

The cut-out portion of the sample was removed, and a rectangular sample having a side of 15 mm was cut out from the applied dry layer, and the sample was pressurized under the condition 1 for 5 minutes to prepare a negative electrode sheet FS-1.

In the preparation of the negative electrode sheet FS-1, the negative electrode sheets FS-2 to FS-13 and the negative electrode sheets FS-2 to FS-13 and HFS-1 to HFS-5 were produced.

[Table 3]

[Note in table]

Content of the dispersion medium of the application|coating dry layer which the sheet|seat produced under condition 2 has is content before pressurization after putting on the hotplate of condition 2.

FS-8 was carried out under vacuum and otherwise heated under atmospheric pressure.

FS-9 was performed by changing the pressurization time of condition 1 from 5 minutes to 2 hours.

Content of a particulate-form organic component is content of solid content.

<Production of all-solid-state secondary battery T1>

As follows, the all-solid-state secondary battery T1 which has the layer structure shown in FIG. 1 was produced.

On the negative electrode active material layer of the negative electrode sheet FS-1, the sheet S-3 for a solid electrolyte layer was superposed so that the negative electrode active material layer and the solid electrolyte layer were in contact, and the laminate thus obtained was pressed at 100 MPa at room temperature, The aluminum foil which sheet|seat S-3 for solid electrolyte layers has was peeled. The solid electrolyte layer and the positive electrode active material layer were brought into contact with this laminate, the sheets having the positive electrode sheet SS-3 were superposed on top of each other, and the laminate obtained in this way was hot-pressed at 150 MPa and 120 ° C. By minute pressurization, the laminated body for all-solid-state secondary batteries was produced.

The all-solid-state secondary battery 13 shown in FIG. 2 was produced using this laminated body for all-solid-state secondary batteries.

The laminated body 12 for all-solid-state secondary batteries was cut out in the disk shape of 10 mm in diameter. A 10 mm diameter all-solid-state secondary battery stack was placed in a stainless steel 2032 type coin case 11 containing spacers and washers (not shown in Fig. 2), and the 2032 type coin case 11 was fixed (constraining pressure) : 0.1 MPa) to produce an all-solid-state secondary battery 13 .

In the production of the all-solid-state secondary battery T1, except that the layer configuration described in Table 4 was adopted, in the same manner as the all-solid-state secondary battery T1, all-solid-state secondary batteries other than the all-solid-state secondary battery T1 described in Table 4 were prepared made

-Cycle characteristic test-

Using the all-solid-state secondary battery produced above, charging and discharging of 4.3V to 3.0V was repeated once under the conditions of 0.1mA before charge and 0.1mA before discharge in an environment of 30°C.

Then, as a cycle test, the test which repeats charging and discharging of 4.3V-3.0V under the conditions of the charge/discharge voltage of 0.6 mA in 25 degreeC environment was implemented.

The discharge capacity at the 1st cycle and the discharge capacity at the 20th cycle were measured and evaluated according to the following evaluation criteria. In this test, "C" or higher is a pass.

Discharge capacity retention rate (%) = (discharge capacity at 20th cycle/1 discharge capacity at cycle) x 100

-Evaluation standard-

A Discharge capacity retention rate: 70% or more and 99% or less

B Discharge capacity retention rate: 60% or more and less than 70%

C Discharge capacity retention rate: more than 50% and less than 60%

D Discharge capacity retention rate: 35% or more and less than 50%

E Discharge capacity retention: less than 35%

-Rate characteristic test-

Using the all-solid-state secondary battery produced above, charging and discharging of 4.3V to 3.0V was performed once under the conditions of 0.1mA before charge and 0.1mA before discharge in an environment of 30°C.

Then, as a rate characteristic test, after charging to 4.3V under the conditions of 0.2mA of pre-charge voltage under 25 degreeC environment, it discharged to 3.0V with 0.2mA pre-discharge value (1st cycle).

Next, in a 25 degreeC environment, after charging to 4.3V under the conditions of 0.2 mA of pre-charge value, it discharged to 3.0 V with 1 mA of pre-discharge values (2nd cycle).

The discharge capacity of the 1st cycle and the discharge capacity of the 2nd cycle were measured, the discharge capacity retention rate was computed from the following formula, and it evaluated according to the following evaluation criteria. "C" or higher is a pass.

Discharge capacity retention rate (%) = (discharge capacity at 2nd cycle/1 discharge capacity at cycle) x 100

-Evaluation standard-

A 55% or more and 99% or less

B 35% or more and less than 55%

C 25% or more and less than 35%

D 10% or more and less than 25%

E less than 10%

-Adhesiveness test-

The stainless foil of the above-mentioned all-solid-state secondary battery laminate cut into a disk shape with a diameter of 10 mm is placed on a table with a 1 cm length and a width of 5 cm tape (trade name: NITTO TAPE P-222, manufactured by Nitto Denko Corporation) laminated for an all-solid-state secondary battery. It affixed on the aluminum foil of a sieve. This tape was peeled with respect to the aluminum foil at an angle of 90° at a tensile rate of 30 mm/min (90° peel test), and peeling occurred between the foil and the constituent layers of the all-solid-state secondary battery laminate or between the constituent layers. The strength of pulling the tape at the time was evaluated by applying the following evaluation criteria.

When only the tape peeled without the said peeling generate|occur|produced, it evaluated again using the other laminated body for all-solid-state secondary batteries.

In this test, "D" or more is a pass.

-Evaluation standard-

A 0.3N/cm or more

B More than 0.2N/cm and less than 0.3N/cm

C 0.1N/cm or more and 0.2N/cm or less

D 0.01N/cm or more and less than 0.1N/cm

E cracks or damage occurred just by attaching the tape.

F cracks or damage occurred before the test.

[Table 4]

As is clear from Table 4, the all-solid-state secondary battery without a sheet obtained by the method for manufacturing the sheet for an all-solid-state secondary battery of the present invention failed both in battery characteristics and binding properties.

On the other hand, the all-solid-state secondary battery which has at least one layer of the sheet|seat obtained by the manufacturing method of the sheet|seat for all-solid-state secondary batteries of this invention passed both a battery characteristic and binding property.

Although the present invention has been described along with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified, and broadly interpret the invention without going against the spirit and scope of the invention as set forth in the appended claims. i think it should be

This application claims priority based on Japanese Patent Application No. 2019-067058 for which a patent application was filed in Japan on March 29, 2019, which takes in the content as a part of description of this specification with reference here.

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 area
10 all-solid-state secondary battery
11 2032 type coin case
12 All-solid-state secondary battery laminate
13 All-solid-state secondary battery (coin battery)

Claims (13)

A method for producing a sheet for an all-solid secondary battery comprising a sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 μm or less and a particulate organic component, the method comprising:
A mixture comprising a particulate organic component and a sulfide-based inorganic solid electrolyte having a volume average particle diameter of 1.0 µm or less, wherein the content of the particulate organic component is 15% by mass or less of the total content of the sulfide-based inorganic solid electrolyte and the particulate organic component is higher than the glass transition temperature of the particulate organic component by 20 ° C. or more and below the decomposition temperature of the particulate organic component, at a pressure higher than 1/10 of the elastic modulus of the particulate organic component, The manufacturing method of the sheet|seat for all-solid-state secondary batteries. The method according to claim 1,
The said elastic modulus is 150 MPa or more, The manufacturing method of the sheet|seat for all-solid-state secondary batteries. The method according to claim 1 or 2,
The manufacturing method of the sheet|seat for all-solid-state secondary batteries with which the said sulfide-type inorganic solid electrolyte and the said particulate-form organic component satisfy|fill the relationship prescribed|regulated by following formula (I) with respect to a volume average particle diameter.
Ba<SEa<20Ba formula (I)
In the formula, SEa is the volume average particle diameter of the sulfide-based inorganic solid electrolyte, and Ba is the volume average particle diameter of the particulate organic component. 4. The method according to any one of claims 1 to 3,
The manufacturing method of the sheet|seat for all-solid-state secondary batteries including the process of adjusting the sulfide-type inorganic solid electrolyte which comprises the said mixture to a volume average particle diameter of 1.0 micrometer or less. 5. The method according to any one of claims 1 to 4,
The manufacturing method of the sheet|seat for all-solid-state secondary batteries in which the said mixture contains an active material. 6. The method of claim 5,
The manufacturing method of the sheet|seat for all-solid-state secondary batteries whose said active material is a negative electrode active material. 7. The method of claim 6,
The manufacturing method of the sheet|seat for all-solid-state secondary batteries in which the said negative electrode active material contains a silicon element or a tin element. 8. The method according to any one of claims 1 to 7,
The said glass transition temperature is 30 degreeC or more, The manufacturing method of the sheet|seat for all-solid-state secondary batteries. 9. The method according to any one of claims 1 to 8,
The manufacturing method of the sheet|seat for all-solid-state secondary batteries which pressurizes the said mixture at the temperature 50 degreeC or more higher than the said glass transition temperature. 10. The method according to any one of claims 1 to 9,
The mixture contains a dispersion medium, and the manufacturing method includes a step of heating the mixture before the pressurization without completely removing the dispersion medium. A method for manufacturing an all-solid-state secondary battery comprising a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order, the method comprising:
The sheet for an all-solid-state secondary battery obtained by the method for manufacturing the sheet for an all-solid-state secondary battery according to any one of claims 1 to 10 is included as at least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer The manufacturing method of the all-solid-state secondary battery including the process of doing. The sheet for all-solid-state secondary batteries obtained by the manufacturing method of the sheet|seat for all-solid-state secondary batteries in any one of Claims 1-10. An all-solid-state secondary battery comprising a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order,
An all-solid-state secondary battery, wherein at least one of the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer is a layer composed of the all-solid-state secondary battery sheet according to claim 12 .

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