JP6709065B2 - Solid electrolyte composition, sheet for all-solid secondary battery and all-solid secondary battery, and sheet for all-solid secondary battery and method for manufacturing all-solid secondary battery - Google Patents

Description

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

A lithium ion secondary battery is a storage battery that has a negative electrode, a positive electrode, and an electrolyte sandwiched between the negative electrode and the positive electrode, and can charge and discharge by moving lithium ions back and forth between both electrodes. Organic electrolytes have been conventionally used as electrolytes in lithium ion secondary batteries. However, the organic electrolyte is liable to leak, and there is a risk of short circuit inside the battery due to overcharging or overdischarging, which may cause ignition, and further improvement in reliability and safety is required.
Under such circumstances, an all-solid secondary battery using an inorganic solid electrolyte in place of the organic electrolytic solution has been receiving attention. The all-solid secondary battery has a solid negative electrode, electrolyte, and positive electrode, which can greatly improve the safety or reliability, which is a problem of batteries using organic electrolytes, and also enables longer life. Will be. Further, the all-solid-state secondary battery can have a structure in which electrodes and electrolytes are directly arranged and arranged in series. Therefore, higher energy density can be achieved as compared with a secondary battery using an organic electrolytic solution, and it is expected to be applied to an electric vehicle, a large storage battery, or the like.

It has been proposed to use a binder in such an all solid state secondary battery. For example, Patent Document 1 describes a lithium battery containing a polymer of an ester or a derivative thereof which is cyclic and has a C=C unsaturated bond in the ring.

JP 2002-042876 A

In recent years, the development of all-solid-state secondary batteries has progressed rapidly, and the performance required for all-solid-state secondary batteries has also increased. In particular, with the increase in the types of products to which the all-solid-state secondary battery is applied, it is desired to develop an all-solid-state secondary battery that can be used under severe conditions.

As an inorganic solid electrolyte used for an all-solid secondary battery, a sulfide-based inorganic solid electrolyte is known to have high ionic conductivity. However, in the lithium battery described in Patent Document 1, the sulfide glass, which is a sulfide-based inorganic solid electrolyte, employs an oxide-based inorganic solid electrolyte because it has poor stability against moisture and oxygen.

An object of the present invention is to provide a solid electrolyte composition that can realize good cycle characteristics even when used in a low temperature (for example, 10° C.) for a certain period of time in an all solid state secondary battery. Another object of the present invention is to provide a sheet for an all-solid secondary battery and an all-solid secondary battery using the above solid electrolyte composition. Further, it is an object of the present invention to provide a sheet for an all-solid secondary battery and a method for producing each of the all-solid secondary batteries.

As a result of intensive studies, the present inventors have found that an all-solid-state secondary battery containing a compound having a specific double bond and a sulfide-based inorganic solid electrolyte exhibits sulfur derived from the sulfide-based inorganic solid electrolyte during electrochemical action. It has been found that a film containing atoms is formed on the surface of the sulfide-based inorganic solid electrolyte, the affinity between the active material and the sulfide-based inorganic solid electrolyte is improved, and the cycle characteristics can be improved. The present invention has been completed through further studies based on these findings.

That is, the above problem was solved by the following means.
<1> A solid electrolyte composition containing a sulfide-based inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or 2 of the periodic table,
A compound having a C=O bond which forms a film on the surface of a sulfide-based inorganic solid electrolyte by an electrochemical action or a compound having an S=O bond which forms a film on the surface of a sulfide-based inorganic solid electrolyte by an electrochemical action , C = O compounds with bonds Ri compound der described below (a), a solid electrolyte composition is a compound according to the compound having an S = O bond below (B).
(A) Carbonate compound having a carbonate group and a halogen atom in the molecule
(B) Sulfite compound, sulfonate compound or sulfone compound

一般式中、Ｒ^Ａ１、Ｒ^Ｂ１、Ｒ^Ｂ２１およびＲ^Ｂ２２は、互いに独立して１価の置換基を表す。Ｒ^Ｂ３は、炭素原子で硫黄原子に結合する１価の置換基を表す。複数のＲ^Ａ１、複数のＲ^Ｂ１および複数のＲ^Ｂ３は、それぞれ互いに同じであっても異なっていても良く、複数のＲ^Ａ１同士、複数のＲ^Ｂ１同士、Ｒ^Ｂ２１とＲ^Ｂ２２、および複数のＲ^Ｂ３同士は、それぞれ環を形成していてもよい。Ｒ^Ａ１の少なくとも１つは、少なくとも１つのハロゲン原子を有する。
< 2 > The carbonate compound is represented by the following general formula (A1), and the sulfite compound, the sulfonate compound and the sulfone compound are each represented by the following general formulas (B1), (B2) and (B3). < 1 > The solid electrolyte composition according to < 1 >.

In the general formula, R ^A1 , R ^B1 , R ^B21 and R ^B22 each independently represent a monovalent substituent. R ^B3 represents a monovalent substituent bonded to a sulfur atom by a carbon atom. Multiple ^{R A1,} the plurality of ^{R B1} and a plurality of ^{R B3,} may be different be the same as each other, respectively, among the plurality of ^{R A1,} a plurality of ^{R B1 between, R B21} and ^{R B22,} and a plurality of Each R ^B3 may form a ring. At least one R ^A1 has at least one halogen atom.

< 3 > The solid electrolyte composition according to < 1 > or < 2 >, in which the compound described in (A) and the compound described in (B) each have a cyclic structure in the molecule.

一般式（Ａ１−２）において、αは５員以上の環を形成するのに必要な原子群を表し、一般式（Ａ１−２）で表される化合物は、ハロゲン原子を少なくとも１つ有する。
一般式（Ｂ１−２）において、βは５員以上の環を形成するのに必要な原子群を表す。
一般式（Ｂ２−２）において、Ｌ^１は−Ｏ−またはアルキレン基を表す。χは５員以上の環を形成するのに必要な原子群を表す。
一般式（Ｂ３−２）において、複数のＬ^２は各々独立してアルキレン基を表す。δは４員以上の環を形成するのに必要な原子群を表す。
< 4 > The compounds represented by the formulas (A1), (B1), (B2) and (B3) are respectively represented by the following formulas (A1-2), (B1-2) and (B2-2). ) And (B3-2) are the compounds represented by the formulas < 2> .

In the general formula (A1-2), α represents an atomic group necessary for forming a ring having 5 or more members, and the compound represented by the general formula (A1-2) has at least one halogen atom.
In the general formula (B1-2), β represents an atomic group necessary for forming a ring having 5 or more members.
In formula (B2-2), L ¹ represents -O- or an alkylene group. χ represents an atomic group necessary for forming a ring having 5 or more members.
In the general formula (B3-2), each L ² independently represents an alkylene group. δ represents an atomic group necessary for forming a ring having 4 or more members.

< 5 > The solid electrolyte composition according to any one of <1> to < 4 >, which contains an electrode active material.
< 6 > The solid electrolyte composition according to < 5 >, wherein the electrode active material is a negative electrode active material.
< 7 > An all-solid secondary battery sheet having a layer of the solid electrolyte composition according to any one of <1> to < 6 > on a substrate.
< 8 > An all-solid-state secondary battery comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer, wherein at least one layer selected from a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer. , An all-solid secondary battery which is a layer formed of the solid electrolyte composition according to any one of <1> to < 6 >.
< 9 > A method for producing a sheet for an all-solid secondary battery, which comprises disposing the solid electrolyte composition according to any one of <1> to < 6 > on a substrate and forming a film from the same.
< 10 > A method for manufacturing an all-solid secondary battery, which manufactures an all-solid secondary battery through the manufacturing method according to < 9 >.

In the present specification, a compound having a C═O bond that forms a film on the surface of a sulfide-based inorganic solid electrolyte by an electrochemical action means a radical anion or a radical cation component generated by a reduction or oxidation reaction. It refers to a compound capable of interacting with the surface component (for example, PS bond) of the solid electrolyte to form a film. At this time, a compound that suppresses an increase in resistance by releasing a halide or the like and capping an active site on the surface of the sulfide-based inorganic solid electrolyte is more preferable. On the other hand, a compound having an S═O bond that forms a film on the surface of a sulfide-based inorganic solid electrolyte by an electrochemical action is similarly defined.
In the present specification, the numerical range represented by using "to" means a range including the numerical values before and after "to" as the lower limit value and the upper limit value.
In the present specification, when simply described as “acrylic” or “(meth)acrylic”, it means methacrylic and/or acrylic.

The solid electrolyte composition of the present invention, when used as a material for a solid electrolyte layer and/or an active material layer of an all-solid secondary battery, can realize good cycle characteristics even when used at a low temperature for a certain period of time. It has an excellent effect. Moreover, the sheet for all-solid-state secondary batteries and the all-solid-state secondary batteries of the present invention utilize the solid electrolyte composition having the above-described excellent effects, and exhibit excellent performance.
Moreover, according to the manufacturing method of the present invention, the sheet for all-solid-state secondary battery and the all-solid-state secondary battery of the present invention can be preferably manufactured.

1 is a vertical cross-sectional view schematically showing an all solid state secondary battery according to a preferred embodiment of the present invention. It is a longitudinal cross-sectional view which shows typically the all-solid-state secondary battery (coin battery) produced in the Example.

The solid electrolyte composition of the present invention comprises a sulfide-based inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or 2 of the periodic table, and a film on the surface of the sulfide-based inorganic solid electrolyte due to electrochemical action. And a compound having an S=O bond forming a film on the surface of the sulfide-based inorganic solid electrolyte by an electrochemical action.
Hereinafter, a sulfide-based inorganic solid electrolyte having conductivity of ions of a metal belonging to Group 1 or 2 of the periodic table may be referred to as a “sulfide-based inorganic solid electrolyte” or an “inorganic solid electrolyte”. Further, a compound having a C=O bond forming a film on the surface of the sulfide-based inorganic solid electrolyte by an electrochemical action, and a compound having an S=O bond forming a film on the surface of the sulfide-based inorganic solid electrolyte by an electrochemical action Either or both of the compounds may be collectively referred to as a "specific additive".
Hereinafter, preferred embodiments thereof will be described. First, an all-solid secondary battery using the solid electrolyte composition of the present invention will be described.

[All solid state secondary battery]
The all-solid secondary battery of the present invention has a positive electrode, a negative electrode facing the positive electrode, and a solid electrolyte layer between the positive electrode and the negative electrode. The positive electrode has a positive electrode active material layer on the positive electrode current collector. The negative electrode has a negative electrode active material layer on the negative electrode current collector.
At least one layer of the negative electrode active material layer, the positive electrode active material layer, and the solid electrolyte layer is preferably formed of the solid electrolyte composition of the present invention described below, and among them, the negative electrode active material layer is the solid electrolyte composition of the present invention. More preferably, it is formed of a material.
The active material layer or the solid electrolyte layer formed of the solid electrolyte composition is preferably the same in the solid content of the solid electrolyte composition with regard to the component species to be contained and the content ratio thereof.
Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited thereto.

FIG. 1 is a schematic cross-sectional view showing 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, and a positive electrode current collector 5 stacked in this order when viewed from the negative electrode side. The adjacent layers are in direct contact with each other. By adopting such a structure, during charging, electrons (e ⁻ ) are supplied to the negative electrode side, 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 can be supplied to the operating portion 6. In the example of the all-solid-state secondary battery shown in the figure, a light bulb is used as a model in the operating portion 6, and the light bulb is adapted to be lit by discharge.

[Positive electrode active material layer, solid electrolyte layer, negative electrode active material layer]
In the all solid state secondary battery 10, the negative electrode active material layer is formed of the solid electrolyte composition of the present invention.
That is, the solid electrolyte layer 3 contains a sulfide-based inorganic solid electrolyte. The solid electrolyte layer usually does not contain a positive electrode active material and/or a negative electrode active material.
Each of the positive electrode active material layer 4 and the negative electrode active material layer 2 contains a positive electrode active material or a negative electrode active material, and further contains a sulfide-based inorganic solid electrolyte. The negative electrode active material layer 2 further contains a specific additive. When the active material layer contains a sulfide-based inorganic solid electrolyte, ionic conductivity can be improved.
The sulfide-based inorganic solid electrolytes 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, either or both of the positive electrode active material layer and the negative electrode active material layer may be simply referred to as an active material layer or an electrode active material layer. Further, either or both of the positive electrode active material and the negative electrode active material may be simply referred to as an active material or an electrode active material.

In the present invention, when the above-mentioned specific additive is used (contained) in combination with solid particles such as a sulfide-based inorganic solid electrolyte and an active material, good cycle characteristics can be realized in an all-solid secondary battery.
The reason is not clear, but it can be considered as follows. In particular, on the surface of the negative electrode, a specific additive reacts with the sulfide-based inorganic solid electrolyte by an electrochemical action, and a film formed on the surface of the sulfide-based inorganic solid electrolyte is a lithium dendrite formed during the charge/discharge process. It is estimated to suppress the outbreak. Further, it is considered that excess Li ions are trapped by the O and S atoms derived from the sulfide-based inorganic solid electrolyte and/or the specific additive. Further, it is considered that the high affinity of the coating film for the active material improves the ionic conductivity. Due to these actions, the all-solid-state secondary battery of the present invention is considered to exhibit good cycle characteristics.
Incidentally, the above-mentioned film is considered to be formed by the binding of a specific additive, and the cause of the reaction for binding is presumed to be mainly caused by the radical anion/cation accompanying the electrochemical action of the active material. It

The thicknesses of the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 are not particularly limited. Considering the dimensions of a general battery, the thickness of each layer is preferably 10 to 1,000 μm, more preferably 20 μm or more and less than 500 μm. In the all solid state secondary battery of the present invention, the thickness of at least one of the positive electrode active material layer 4, the solid electrolyte layer 3, and the negative electrode active material layer 2 is more preferably 50 μm or more and less than 500 μm.

[Current collector (metal foil)]
The positive electrode current collector 5 and the negative electrode current collector 1 are preferably electron conductors.
In the present invention, either or both of the positive electrode current collector and the negative electrode current collector may be simply referred to as a current collector.
As a material for forming the positive electrode current collector, aluminum, aluminum alloy, stainless steel, nickel, titanium, etc., as well as aluminum or stainless steel whose surface is treated with carbon, nickel, titanium or silver (a thin film is formed) Those), and among them, aluminum and aluminum alloys are more preferable.
As the material for forming the negative electrode current collector, in addition to aluminum, copper, copper alloy, stainless steel, nickel, titanium, etc., the surface of aluminum, copper, copper alloy, stainless steel is treated with carbon, nickel, titanium or silver. It is preferable to use aluminum, copper, a copper alloy, and stainless steel.

The shape of the current collector is usually a film sheet, but a net, a punch, a lath, a porous body, a foam, a molded body of fibers, and the like can also be used.
The thickness of the current collector is not particularly limited, but is preferably 1 to 500 μm. Further, it is also preferable that the surface of the current collector is made uneven by surface treatment.

In the present invention, a functional layer or member is 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. You may. Each layer may be composed of a single layer or multiple layers.

(Case)
The basic structure of an all-solid-state secondary battery can be produced by arranging the above layers. Depending on the application, it may be used as it is as an all-solid-state secondary battery, but in order to obtain the form of a dry battery, it is further enclosed in a suitable casing for use. The housing may be made of metal or resin (plastic). When using a metallic thing, the thing made from an aluminum alloy and the thing made from stainless steel can be mentioned, for example. The metallic casing is preferably divided into a casing on the positive electrode side and a casing 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 housing on the positive electrode side and the housing on the negative electrode side are joined and integrated via a gasket for preventing a short circuit.

[Solid electrolyte composition]
The solid electrolyte composition of the present invention is as described above, and will be specifically described below.

(Inorganic solid electrolyte)
The solid electrolyte composition of the present invention contains a sulfide-based inorganic solid electrolyte.
The solid electrolyte of the inorganic solid electrolyte is a solid electrolyte in which ions can move. Since it does not contain an organic substance as a main ionic conductivity material, it is an organic solid electrolyte (a polymer electrolyte represented by polyethylene oxide (PEO) or the like, or an organic solid electrolyte represented by lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) or the like. Electrolyte salt) is clearly distinguished. Further, since the inorganic solid electrolyte is solid in the steady state, it is not dissociated or released into cations and anions. In this respect, it is also clearly distinguished from inorganic electrolyte salts (LiPF ₆ , LiBF ₄ , lithium bis(fluorosulfonyl)imide (LiFSI), LiCl, etc.) in which cations and anions are dissociated or released in the electrolytic solution or polymer. .. The inorganic solid electrolyte is not particularly limited as long as it has ion conductivity of a metal element belonging to Group 1 or Group 2 of the periodic table, and generally has no electron conductivity. When the all-solid secondary battery of the present invention is a lithium ion battery, the sulfide-based inorganic solid electrolyte preferably has ionic conductivity of lithium ions.
In the present invention, from the viewpoint that a better interface can be formed between the active material and the inorganic solid electrolyte, a sulfide-based inorganic material having ion conductivity of a metal belonging to Group 1 or 2 of the periodic table. A solid electrolyte is used.
-Sulfide inorganic solid electrolyte-
The sulfide-based inorganic solid electrolyte is one that contains a sulfur atom (S), has the ionic conductivity of a metal element belonging to Group 1 or 2 of the periodic table, and has electronic insulation. preferable. The sulfide-based inorganic solid electrolyte preferably contains at least Li, S and P as elements and has lithium ion conductivity, but other than Li, S and P depending on the purpose or case. It may contain an element.
For example, a lithium ion conductivity inorganic solid electrolyte satisfying the composition represented by the following formula (1) can be mentioned, which is preferable.

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. Among them, B, Sn, Si, Al or Ge is preferable, and Sn, Al or Ge is more preferable.
A represents I, Br, Cl or F, preferably I or Br, and particularly preferably I.
Each of L, M and A can be one or more of the above elements.
a1 to e1 represent the composition ratio of each element, and a1:b1:c1:d1:e1 satisfies 1 to 12:0 to 1:1:2 to 12:0 to 5. Further, a1 is preferably 1 to 9, and more preferably 1.5 to 4. b1 is preferably 0 to 0.5. 3-7 are preferable and, as for d1, 3.25-4.5 are more preferable. Further, e1 is preferably 0 to 3, and more preferably 0 to 1.

In the formula (1), the composition ratio of L, M, P, S and A is preferably such that b1 and e1 are 0, more preferably b1=0, e1=0 and the ratio of a1, c1 and d1 is a1:c1:d1=1-9:1:3-7, more preferably b1=0, e1=0 and a1:c1:d1=1.5-4:1:3.25-4. It is 5. The composition ratio of each element can be controlled by adjusting the compounding quantity of the raw material compound at the time of producing a sulfide-based inorganic solid electrolyte, as described later.

The sulfide-based inorganic solid electrolyte may be non-crystalline (glass) or crystallized (glass-ceramic), or only a part thereof may be 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 includes [1] lithium sulfide (Li ₂ S) and phosphorus sulfide (for example, phosphorus pentasulfide (P ₂ S ₅ )), [2] lithium sulfide and at least one of elemental phosphorus and elemental sulfur, Alternatively, [3] it can be produced by the reaction of lithium sulfide with phosphorus sulfide (for example, phosphorus pentasulfide (P ₂ S ₅ )) and at least one of elemental phosphorus and elemental sulfur.

In Li-P-S based glass and Li-P-S based glass ceramics, the ratio of Li ₂ S and _P 2 _{S 5 is,} Li 2 _S: at a molar ratio of P 2 _{S 5,} preferably 65:35 It is 85:15, more preferably 68:32 to 77:23. By setting the ratio of Li ₂ S and P ₂ S ₅ in this range, the lithium ion conductivity can be further increased. Specifically, the lithium ion conductivity can be preferably 1×10 ⁻⁴ S/cm or more, more preferably 1×10 ⁻³ S/cm or more. There is no particular upper limit, but it is practically 1×10 ⁻¹ S/cm or less.

Specific examples of the sulfide-based inorganic solid electrolyte include, for example, those obtained by using a raw material composition containing Li ₂ S and a sulfide of an element of Group 13 to Group 15. it can. More _{specifically, Li 2 S-P 2 S} 5, Li 2 S-LiI-P 2 S 5, Li 2 S-LiI-Li 2 O-P 2 S 5, Li 2 S-LiBr-P 2 S _{5, Li 2 S-Li 2} O-P 2 S 5, Li 2 S-Li 3 PO 4 -P 2 S 5, Li 2 S-P 2 S 5 -P 2 O 5, Li 2 S-P 2 S _{5 -SiS 2, Li 2 S-} P 2 S 5 -SnS, Li 2 S-P 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, such as _{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 .. Among _{them, Li 2 S-P 2 S} 5, Li 2 S-GeS 2 -Ga 2 S 3, Li 2 S-SiS 2 -P 2 S 5, Li 2 S-SiS 2 -Li 4 SiO 4, Li 2 _{S-SiS 2 -Li 3 PO 4} , Li 2 S-LiI-Li 2 O-P 2 S 5, Li 2 S-Li 2 O-P 2 S 5, Li 2 S-Li 3 PO 4 -P 2 S ₅ , the crystalline, amorphous or crystalline and amorphous mixed raw material composition of Li _2, S-GeS ₂ -P ₂ S ₅ , and Li ₁₀ GeP ₂ S ₁₂ has high lithium ion conductivity. preferable. An example of a method for synthesizing a sulfide-based inorganic solid electrolyte material using such a raw material composition is an amorphization method. Examples of the amorphization method include a mechanical milling method and a melt quenching method, and among them, the mechanical milling method is preferable. This is because the treatment can be performed at room temperature and the manufacturing process can be simplified.
Among _{them, Li 2 S-P 2 S} 5, LGPS (Li 10 GeP 2 S 12), Li 2 S-P 2 S 5 -SiS 2 and the like are preferable.

The inorganic solid electrolyte is preferably particles. The volume average particle diameter of the particulate inorganic solid electrolyte is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.1 μm or more. The upper limit is preferably 100 μm or less, more preferably 50 μm or less. The volume average particle size of the inorganic solid electrolyte is measured by the following procedure. The inorganic solid electrolyte particles are prepared by diluting a 1% by mass dispersion liquid in a 20 mL sample bottle with water (heptane in the case of a substance which is unstable to water). The diluted dispersion sample is irradiated with ultrasonic waves of 1 kHz for 10 minutes, and immediately thereafter, used for the test. Using this dispersion liquid sample, using a laser diffraction/scattering particle size distribution analyzer LA-920 (trade name, manufactured by HORIBA), data was captured 50 times using a measuring quartz cell at a temperature of 25° C., Obtain the volume average particle size. For other detailed conditions and the like, refer to the description of JISZ8828:2013 “Particle size analysis-dynamic light scattering method” as necessary. Five samples are prepared for each level, and the average value is adopted.

The content of the inorganic solid electrolyte in the solid electrolyte composition should be 1% by mass or more at a solid content of 100% by mass in consideration of reduction of interface resistance and maintenance of battery characteristics (improvement of cycle characteristics). Is more preferable, 3% by mass or more is more preferable, and 5% by mass or more is particularly preferable. From the same viewpoint, the upper limit is preferably 99% by mass or less, more preferably 90% by mass or less, and particularly preferably 80% by mass or less.
However, when the positive electrode active material or the negative electrode active material is contained, the content of the inorganic solid electrolyte in the solid electrolyte composition is such that the total content of the positive electrode active material or the negative electrode active material and the inorganic solid electrolyte is in the above range. Is preferred.
In the present specification, the solid content means a component that does not disappear by volatilization or evaporation when a drying process is performed at 170° C. for 6 hours under a nitrogen atmosphere. Typically, it refers to components other than the dispersion medium described below.
The inorganic solid electrolytes may be used alone or in combination of two or more.

(Specific additives)
The solid electrolyte composition of the present invention is a compound having a C═O bond that forms a film on the surface of a sulfide-based inorganic solid electrolyte by an electrochemical action (for example, an electrochemical reaction) or a sulfide-based inorganic solid electrolyte by an electrochemical action. It contains a compound having an S=O bond that forms a film on the surface.
Hereinafter, a compound having a C=O bond that forms a film on the surface of a sulfide-based inorganic solid electrolyte by an electrochemical action may be referred to as a C=O compound. On the other hand, a compound having an S=O bond that forms a film on the surface of a sulfide-based inorganic solid electrolyte by an electrochemical action may be referred to as an S=O compound.

In the present invention, since it is possible to oxidize or reduce at a potential within the operating range of an all-solid-state secondary battery and effectively coat reaction reactive sites, the above C═O compound is a compound described in (A) below. And it is preferable that the S═O compound is a compound described in (B) below.
(A) Carbonate compound having a carbonate group (-OC(=O)O-) and a halogen atom in the molecule (B) Sulfite compound, sulfonate compound or sulfone compound

In the present invention, since the oxygen atom and the sulfur atom form a film having high affinity with the sulfide-based inorganic solid electrolyte, the carbonate compound is represented by the following general formula (A1), and the sulfite compound and the sulfonate compound are And the sulfone compound are preferably represented by the following general formulas (B1), (B2) and (B3), respectively.

In the general formula, R ^A1 , R ^B1 , R ^B21 and R ^B22 each independently represent a monovalent substituent. R ^B3 represents a monovalent substituent bonded to a sulfur atom by a carbon atom. Multiple ^{R A1,} the plurality of ^{R B1} and a plurality of ^{R B3,} may be different be the same as each other, respectively, among the plurality of ^{R A1,} a plurality of ^{R B1 between, R B21} and ^{R B22,} and a plurality of R ^B3s may form a ring in the compound represented by each general formula. At least one R ^A1 has at least one halogen atom.

Specific examples of the monovalent substituent represented by R ^A1 , R ^B1 , R ^B21 and R ^B22 and the monovalent substituent bonded to the sulfur atom by the carbon atom represented by R ^B3 include the substituent Z described below. Substituents selected from

In the general formula (A1), at least one of the monovalent substituents represented by R ^A1 has at least one halogen atom. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable among them.
In the general formula (A1), the monovalent substituent represented by R ^A1 is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, an alkylsilyl group or an arylsilyl group in the substituent Z described later. Is preferred, and an alkyl group is more preferred. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group. The alkyl group preferably has a halogen atom at the terminal carbon atom, more preferably all the hydrogen atoms of the terminal carbon atoms are replaced with halogen atoms, and particularly preferably a perfluoroalkyl group.

In the general formula (B1), the monovalent substituent represented by R ^B1 is an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, an alkylsilyl group or an arylsilyl group in the substituent Z described later. Is preferred, and an alkyl group is more preferred. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group.

In the general formula (B2), as the monovalent substituent represented by R ^B21 , an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a heterocyclic group, an amino group alkyl in the below-described substituent Z is represented. A silyl group or an arylsilyl group is preferable, and an alkyl group, an aryl group or an alkenyl group is more preferable. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group. The aryl group preferably has 6 to 12 carbon atoms, more preferably has 6 to 8 carbon atoms, and particularly preferably a phenyl group.
In the general formula (B2), the monovalent substituent represented by R ^B22 is an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a heterocyclic group, an alkylsilyl group or an arylsilyl group in the substituent Z described later. Is preferred, an alkyl group or an aryl group is more preferred, and an alkyl group is particularly preferred. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group. The alkyl group may have a halogen atom (preferably a fluorine atom) which R ^A1 has. The aryl group preferably has 6 to 12 carbon atoms, more preferably has 6 to 8 carbon atoms, and particularly preferably a phenyl group.

In the general formula (B3), the monovalent substituent represented by R ^B3 is an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a heterocyclic group, an alkylsilyl group or an arylsilyl group in the substituent Z described later. Is preferred, and an alkyl group is more preferred. 1-10 are more preferable, as for carbon number of an alkyl group, 1-5 are more preferable, and 1-3 are especially preferable. The aryl group preferably has 6 to 12 carbon atoms, more preferably has 6 to 8 carbon atoms, and particularly preferably has 6 carbon atoms.

In the present invention, the coating formed by ring opening due to the electrochemical action is stronger and can be maintained during the long-term use of the all-solid-state secondary battery. The compound described in (B) preferably has a cyclic structure in the molecule.

The compounds represented by the formulas (A1), (B1), (B2) and (B3) are respectively represented by the following formulas (A1-2), (B1-2), (B2-2) and (B2-2). It is preferably a compound represented by each formula of B3-2).

In the general formula (A1-2), α represents an atomic group necessary for forming a ring having 5 or more members, and the compound represented by the general formula (A1-2) has at least one halogen atom.
In the general formula (B1-2), β represents an atomic group necessary for forming a ring having 5 or more members.
In formula (B2-2), L ¹ represents -O- or an alkylene group. χ represents an atomic group necessary for forming a ring having 5 or more members.
In the general formula (B3-2), each L ² independently represents an alkylene group. δ represents an atomic group necessary for forming a ring having 4 or more members.

The ring-constituting atoms of the atomic group necessary for forming a 5-membered or more-membered ring in formula (A1-2) are preferably atoms selected from carbon atoms and oxygen atoms. The ring in general formula (A1-2) is preferably a non-aromatic ring.
The ring in formula (A1-2) is preferably a 5- to 8-membered ring, more preferably a 5- or 6-membered ring, and particularly preferably a 5-membered ring. The ring in formula (A1-2) has at least one halogen atom (preferably a fluorine atom), preferably has 1 to 3 halogen atoms, and more preferably has 1 or 2 halogen atoms. It is more preferred to have one halogen atom. When the ring in the general formula (A1-2) has a substituent, this substituent may have a halogen atom.
As the substituent which the ring in the general formula (A1-2) has, an alkyl group, a halogen atom, an aryl group, an alkenyl group or an alkynyl group in the substituent Z described later is preferable, and a fluorinated alkyl group or a fluorine atom is more preferable. . The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group.

The ring-constituting atoms of the atomic group necessary for forming a 5-membered or more ring in the general formula (B1-2) are preferably atoms selected from a sulfur atom, a carbon atom and an oxygen atom. In addition, the ring in the general formula (B1-2) is preferably a non-aromatic ring.
The ring in general formula (B1-2) is preferably a 5- to 8-membered ring, more preferably a 5- or 6-membered ring, and particularly preferably a 5-membered ring.
The ring in formula (B1-2) may have a substituent. As the substituent which the ring in the general formula (B1-2) has, an alkyl group, an aryl group, an alkenyl group or an alkynyl group in the substituent Z described later is preferable, and an alkyl group is more preferable. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group.

The ring-constituting atoms of the atomic group necessary for forming a 5-membered or more-membered ring in the general formula (B2-2) are preferably atoms selected from a sulfur atom, a carbon atom and an oxygen atom. The ring in general formula (B2-2) is preferably a non-aromatic ring.
The alkylene group represented by L ¹ is preferably an alkylene group having 1 to 5 carbon atoms, and more preferably an alkylene group having 1 to 3 carbon atoms. Specific examples of the alkylene group include methylene, ethylene and propylene. The alkylene group represented by L ¹ may have a substituent, and specific examples of the substituent include a substituent selected from the substituent Z described later.
The ring in general formula (B2-2) is preferably a 5- to 8-membered ring, more preferably a 5- or 6-membered ring, and particularly preferably a 5-membered ring.
The ring in general formula (B2-2) may have a substituent. As the substituent which the ring in the general formula (B2-2) has, an alkyl group in the substituent Z described later is preferable. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group.

The ring-constituting atoms of the atomic group necessary for forming a 4-membered or more-membered ring in the general formula (B3-2) are preferably atoms selected from a sulfur atom and a carbon atom. The ring in general formula (B3-2) is preferably a non-aromatic ring.
The alkylene group represented by L ² is preferably an alkylene group having 1 to 5 carbon atoms, and more preferably an alkylene group having 1 to 3 carbon atoms. Specific examples of the alkylene group include methylene, ethylene and propylene. The alkylene group represented by L ² may have a substituent, and specific examples of the substituent include a substituent selected from the substituent Z described later.
The ring in formula (B3-2) is preferably a 4- to 8-membered ring, more preferably a 5- or 6-membered ring, and particularly preferably a 5-membered ring.
The ring in general formula (B3-2) may have a substituent. As the substituent which the ring in the general formula (B3-2) has, an alkyl group, an aryl group, an alkenyl group, an alkynyl group or =O in the substituent Z described later is preferable, and an alkyl group and =O are preferable. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group.

In the present specification, the expression of a compound (for example, when it is referred to as a compound at the end) includes the compound itself, a salt thereof, and an ion thereof. Further, it is meant to include a derivative in which a part of the derivative is changed, such as by introducing a substituent, within a range in which a desired effect is exhibited.
In the present specification, with respect to a substituent which is not specified to be substituted or unsubstituted (the same applies to the linking group), it means that the group may have an appropriate substituent. This is also synonymous with compounds that do not specify substituted or unsubstituted. The following substituent Z is mentioned as a preferable substituent.

Further, in the present specification, when simply described as a YYY group (for example, an alkyl group), the YYY group is selected from the following substituents Z corresponding to this group.
Examples of the substituent Z include the followings.
Alkyl group (preferably alkyl group having 1 to 20 carbon atoms, for example, methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl A group (preferably an alkenyl group having 2 to 20 carbon atoms, for example, vinyl, allyl, oleyl, etc.), an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, for example, ethynyl, butadiynyl, phenylethynyl, etc.), Cycloalkyl group (preferably a cycloalkyl group having 3 to 20 carbon atoms, for example, cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc. However, when the alkyl group is used in the present specification, it is usually meant to include a cycloalkyl group. ), an aryl group (preferably an aryl group having 6 to 26 carbon atoms, for example, phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), an aralkyl group (preferably having 7 carbon atoms). To 23 aralkyl groups such as benzyl and phenethyl, heterocyclic groups (preferably having 2 to 20 carbon atoms, preferably 5 or 6 having at least one oxygen atom, sulfur atom, nitrogen atom). Member-membered heterocyclic groups are preferred, for example, tetrahydropyran, tetrahydrofuran, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, pyrrolidone groups), alkoxy groups (preferably). An alkoxy group having 1 to 20 carbon atoms, for example, methoxy, ethoxy, isopropyloxy, benzyloxy, etc., an aryloxy group (preferably an aryloxy group having 6 to 26 carbon atoms, for example, phenoxy, 1-naphthyloxy, 3-Methylphenoxy, 4-methoxyphenoxy and the like, however, when the alkoxy group is used in the present specification, it usually means that it includes an aryloyl group.), an alkoxycarbonyl group (preferably an alkoxycarbonyl group having 2 to 20 carbon atoms, for example, Ethoxycarbonyl, 2-ethylhexyloxycarbonyl, etc., an aryloxycarbonyl group (preferably an aryloxycarbonyl group having 6 to 26 carbon atoms, for example, phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxy. Phenoxycarbonyl, etc.), amino group (preferably amino group having 0 to 20 carbon atoms, alkylamido) Group, including an amino group and an arylamino group, for example, amino, N,N-dimethylamino, N,N-diethylamino, N-ethylamino, anilino, etc., sulfamoyl group (preferably a sulfamoyl group having 0 to 20 carbon atoms, For example, N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), an acyl group (preferably an acyl group having 1 to 20 carbon atoms, for example, acetyl, propionyl, butyryl, etc.), an aryloyl group (preferably An aryloyl group having 7 to 23 carbon atoms, for example, benzoyl, etc., but when referred to as an acyl group in the present specification, it is usually meant to include an aryloyl group. ), an acyloxy group (preferably an acyloxy group having 1 to 20 carbon atoms, for example, acetyloxy and the like), an aryloyloxy group (preferably an aryloyloxy group having 7 to 23 carbon atoms, for example, benzoyloxy and the like, In the present specification, an acyloxy group is meant to include an aryloyloxy group, a carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, for example, N,N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.). ), an acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, for example, acetylamino, benzoylamino, etc.), an alkylthio group (preferably an alkylthio group having 1 to 20 carbon atoms, for example, methylthio, ethylthio, isopropylthio. , Benzylthio, etc.), an arylthio group (preferably an arylthio group having 6 to 26 carbon atoms, for example, phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), an alkylsulfonyl group (preferably carbon atoms). An alkylsulfonyl group having 1 to 20 atoms, such as methylsulfonyl, ethylsulfonyl, etc., an arylsulfonyl group (preferably an arylsulfonyl group having 6 to 22 carbon atoms, such as benzenesulfonyl), an alkylsilyl group (preferably carbon). An alkylsilyl group having 1 to 20 atoms, for example, monomethylsilyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), an arylsilyl group (preferably an arylsilyl group having 6 to 42 carbon atoms, for example, triphenylsilyl, etc.), An alkoxysilyl group (preferably an alkoxysilyl group having 1 to 20 carbon atoms, for example, monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.), an aryloxysilyl group (preferably having 6 to 42 carbon atoms) aryloxy silyl group, for example, triphenyl oxysilyl etc.), a phosphoryl group (preferably phosphoryl group of 0-20 carbon atoms, for ^{example, -OP (= O) (R} P) 2), a phosphonyl group (preferably a carbon phosphonyl group atoms from 0 to 20, for ^{example, -P (= O) (R} P) 2), a phosphinyl group (preferably a phosphinyl group having 0 to 20 carbon atoms, for _{^{example, -P (R P) 2)}} , (Meth)acryloyl group, (meth)acryloyloxy group, (meth)acryloylimino group ((meth)acrylamide group), hydroxy group, thiol group , Carboxy group, phosphoric acid group, phosphonic acid group, sulfonic acid group, cyano group, halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom) and ═O.
In addition, each of the groups listed as the substituent Z may be further substituted with the above-mentioned substituent Z.
When the compound, the substituent, the linking group or the like contains an alkyl group, an alkylene group, an alkenyl group, an alkenylene group, an alkynyl group and/or an alkynylene group, these may be cyclic or linear, or linear or branched. It may be substituted or not as described above.

Specific examples of specific additives are shown below, but the present invention is not limited thereto.

The above-mentioned specific additives may be used alone or in combination of two or more. The above-mentioned specific additive can be synthesized by a conventional method.

The content of the specific additive capable of forming a film on the surface of the sulfide-based inorganic solid electrolyte in the solid electrolyte composition is not particularly limited, and is preferably 0.01 to 20 mass% at 100 mass% solid content. , 0.05 to 10 mass% is more preferable, and 0.1 to 5 mass% is particularly preferable.

(Active material)
The solid electrolyte composition of the present invention may contain an active material capable of inserting and releasing ions of a metal element belonging to Group 1 or 2 of the periodic table. Examples of the active material include a positive electrode active material and a negative electrode active material, which will be described below. A transition metal oxide that is a positive electrode active material or a carbonaceous material that is a negative electrode active material is preferable. The solid electrolyte composition of the present invention contains a negative electrode active material because the coating film formed by the reduction reaction is particularly strong and can form a coating film having a high affinity with the sulfide-based inorganic solid electrolyte. Preferably.
In the present invention, the solid electrolyte composition containing the active material (positive electrode active material, negative electrode active material) may be referred to as an electrode layer composition (positive electrode layer composition, negative electrode layer composition).

-Cathode active material-
The positive electrode active material that may be contained in the solid electrolyte composition of the present invention is preferably one that can reversibly insert and release lithium ions. The material is not particularly limited as long as it has the above characteristics, and may be a transition metal oxide, an element that can be complexed with Li such as sulfur, or the like.
Among them, as the positive electrode active material, a transition metal oxide having preferably used a transition metal oxide, a transition metal element ^M a a (Co, Ni, Fe, Mn , 1 or more elements selected from Cu and V) The thing is more preferable. Further, the element M ^b (elements of Group 1 (Ia) other than lithium, elements of Group 1 (Ia), elements of Group 2 (IIa), Al, Ga, In, Ge, Sn, Pb, Elements such as Sb, Bi, Si, P or B) may be mixed. The mixing amount, 0~30mol% is preferred for the amount of the transition metal element ^{M a (100mol%).} That the molar ratio of li / ^{M a} is synthesized by mixing so that 0.3 to 2.2 is more preferable.
Specific examples of the transition metal oxide include (MA) a transition metal oxide having a layered rock salt type structure, (MB) a transition metal oxide having a spinel type structure, (MC) a lithium-containing transition metal phosphate compound, (MD) ) Lithium-containing transition metal halogenated phosphoric acid compounds and (ME) lithium-containing transition metal silicic acid compounds.

Specific examples of the transition metal oxide having a (MA) layered rock salt structure include LiCoO ₂ (lithium cobalt oxide [LCO]), LiNi ₂ O ₂ (lithium nickelate) LiNi _0.85 Co _0.10 Al _0.05. O ₂ (lithium nickel cobalt aluminum oxide [NCA]), LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (lithium nickel manganese cobalt oxide [NMC]) and LiNi _0.5 Mn _0.5 O ₂ (manganese) Lithium nickelate).
Specific examples of the transition metal oxide having a (MB) spinel structure include 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. ..
Examples of the (MC) 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 LiCoPO _4. Cobalt phosphates and Li ₃ V ₂ (PO ₄ ) ₃ (lithium vanadium phosphate), and monoclinic NASICON type vanadium phosphate salts.
(MD) as the lithium-containing transition metal halogenated phosphate compound, for _example, Li 2 FePO ₄ F such fluorinated phosphorus iron _salt, Li 2 MnPO ₄ hexafluorophosphate manganese salts such as F and _Li 2 CoPO ₄ F And the like, such as cobalt fluorophosphates.
Examples of the (ME) lithium-containing transition metal silicic acid compound include Li ₂ FeSiO ₄ , Li ₂ MnSiO _4, and Li ₂ CoSiO ₄ .
In the present invention, a transition metal oxide having a (MA) layered rock salt structure is preferable, and LCO, NCA or NMC is more preferable.

The shape of the positive electrode active material is not particularly limited, but a particle shape is preferable. The volume average particle diameter (sphere-converted average particle diameter) of the positive electrode active material is not particularly limited. For example, it can be 0.1 to 50 μm. In order to make the positive electrode active material have a predetermined particle size, an ordinary crusher or classifier may be used. The positive electrode active material obtained by the firing method may be used after washing with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent. The volume average particle diameter (sphere-converted average particle diameter) of the positive electrode active material particles can be measured using a laser diffraction/scattering type particle size distribution measuring device LA-920 (trade name, manufactured by HORIBA).

The positive electrode active material may be used alone or in combination of two or more.
When the positive electrode active material layer is formed, the mass (mg) (unit weight) of the positive electrode active material per unit area (cm ² ) of the positive electrode active material layer is not particularly limited. It can be appropriately determined according to the designed battery capacity.

The content of the positive electrode active material in the solid electrolyte composition is not particularly limited and is preferably 10 to 99% by mass, more preferably 30 to 95% by mass, and 50 to 90% by mass in 100% by mass of solid content. More preferably, 60 to 90 mass% is particularly preferable.

-Negative electrode active material-
The negative electrode active material that may be contained in the solid electrolyte composition of the present invention is preferably one that can reversibly insert and release lithium ions. The material is not particularly limited as long as it has the above characteristics, carbonaceous materials, metal oxides such as tin oxide, silicon oxide, metal composite oxides, lithium simple substances and lithium alloys such as lithium aluminum alloys, and , Sn, Si, In, and other metals capable of forming an alloy with lithium. Among them, carbonaceous materials or lithium composite oxides are preferably used from the viewpoint of reliability. Further, the metal composite oxide is preferably capable of inserting and extracting lithium. The material is not particularly limited, but it is preferable that titanium and/or lithium is contained as a constituent component from the viewpoint of high current density charge/discharge characteristics.

The carbonaceous material used as the negative electrode active material is a material consisting essentially of carbon. For example, petroleum pitch, carbon black such as acetylene black (AB), graphite (natural graphite, artificial graphite such as vapor-grown graphite), and PAN (polyacrylonitrile)-based resins and furfuryl alcohol resins A carbonaceous material obtained by firing a resin can be used. Further, various carbon fibers such as PAN-based carbon fibers, cellulose-based carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, dehydrated PVA (polyvinyl alcohol)-based carbon fibers, lignin carbon fibers, glassy carbon fibers, activated carbon fibers, etc. Examples thereof include mesophase microspheres, graphite whiskers, and tabular graphite.

These carbonaceous materials can be divided into non-graphitizable carbonaceous materials and graphitic carbonaceous materials depending on the degree of graphitization. Further, the carbonaceous material preferably has the interplanar spacing, the density and the crystallite size described in JP-A-62-122066, JP-A-2-6856 and/or JP-A-3-45473. .. The carbonaceous material does not have to be a single material, and a mixture of natural graphite and artificial graphite described in JP-A-5-90844 and graphite having a coating layer described in JP-A-6-4516 may be used. You can also

As the metal oxide and metal composite oxide applied as the negative electrode active material, an amorphous oxide is particularly preferable, and chalcogenite which is a reaction product of a metal element and an element of Group 16 of the periodic table is also preferably used. Be done. The term "amorphous" as used herein refers to an X-ray diffraction method using CuKα rays, which has a broad scattering band having an apex in the region of 20 to 40 at a 2θ value, and a crystalline diffraction line. May have. The strongest intensity of the crystalline diffraction lines observed at 2θ values of 40° or more and 70° or less is 100 times or less than the diffraction line intensity of the apex of the broad scattering band observed at 2θ values of 20° or more and 40° or less. Is more preferable, it is more preferably 5 times or less, and it is particularly preferable not to have a crystalline diffraction line.

Among the compounds consisting of the above amorphous oxides and chalcogenides, amorphous oxides of metalloid elements and chalcogenides are more preferable, and elements of Group 13 (IIIB) to 15 (VB) of the periodic table, Al , Ga, Si, Sn, Ge, Pb, Sb and Bi alone or a combination of two or more thereof, and chalcogenide are particularly preferable. Specific examples of preferable amorphous oxides and chalcogenides include Ga ₂ O ₃ , SiO, GeO, SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₂ O ₄ , Pb ₃ O ₄ , and Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₈ i ₂ O ₃ , Bi ₂ O ₄ , SnSiO ₃ , GeS, SnS, SnS ₂ , PbS, PbS ₂ , Sb ₂ S ₃ , Sb ₂ S ₅ and SnSiS. ₃ is preferably mentioned. In addition, these may be a composite oxide with lithium oxide, for example, Li ₂ SnO ₂ .

It is also preferable that the negative electrode active material contains a titanium atom. More specifically, Li ₄ Ti ₅ O ₁₂ (lithium titanate [LTO]) is excellent in rapid charging/discharging characteristics because of its small volume fluctuation at the time of inserting and extracting lithium ions, suppressing deterioration of the electrode, and suppressing lithium ion secondary It is preferable in that the life of the battery can be improved.

In the present invention, hard carbon or graphite is preferably used. In the present invention, the carbonaceous materials may be used alone or in combination of two or more.

The shape of the negative electrode active material is not particularly limited, but a particle shape is preferable. The average particle diameter of the negative electrode active material is preferably 0.1 to 60 μm. An ordinary crusher or classifier is used to obtain a predetermined particle size. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling airflow type jet mill, a sieve and the like are preferably used. At the time of pulverization, wet pulverization in which water or an organic solvent such as methanol is allowed to coexist can be performed as necessary. In order to obtain the desired particle size, it is preferable to carry out classification. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be used both dry and wet. The average particle diameter of the negative electrode active material particles can be measured by the same method as the method for measuring the volume average particle diameter of the positive electrode active material described above.

The chemical formula of the compound obtained by the above calcination method can be calculated from the mass difference of the powder before and after calcination as a simple method, and as a simple method.

Examples of the negative electrode active material that can be used in combination with the amorphous oxide negative electrode active material centered on Sn, Si, and Ge include carbon materials that can store and release lithium ions or lithium metal, lithium, lithium alloys, and lithium. A metal that can be alloyed with is suitable.

In the present invention, it is also preferable to apply a Si-based negative electrode. Generally, a Si negative electrode can occlude more Li ions than a carbon negative electrode (graphite, acetylene black, etc.). That is, the storage amount of Li ions per unit weight increases. Therefore, the battery capacity can be increased. As a result, there is an advantage that the battery drive time can be lengthened.

The negative electrode active material may be used alone or in combination of two or more.
When the negative electrode active material layer is formed, the mass (mg) (unit weight) of the negative electrode active material per unit area (cm ² ) of the negative electrode active material layer is not particularly limited. It can be appropriately determined according to the designed battery capacity.

The content of the negative electrode active material in the solid electrolyte composition is not particularly limited, and is preferably 10 to 99% by mass, more preferably 20 to 90% by mass, and 30 to 80% based on 100% by mass of the solid content. It is more preferably mass%, and further preferably 40 to 70 mass%.

(binder)
The solid electrolyte composition of the present invention may contain a binder.
The binder used in the present invention is not particularly limited as long as it is an organic polymer.
The binder that can be used in the present invention is generally preferably a binder used as a binder for a positive electrode or a negative electrode of a battery material, and is not particularly limited, and for example, a binder made of the resin described below is preferable. A granular binder is particularly preferable.

Examples of the fluorine-containing resin include polytetrafluoroethylene (PTFE), polyvinylene difluoride (PVdF), and a copolymer of polyvinylene difluoride and hexafluoropropylene (PVdF-HFP). In the present invention, PVdF-HFP is preferably used.
Examples of the hydrocarbon-based thermoplastic resin include polyethylene, polypropylene, styrene butadiene rubber (SBR), hydrogenated styrene butadiene rubber (HSBR), butylene rubber, acrylonitrile butadiene rubber, polybutadiene and polyisoprene.
Examples of the acrylic resin include methyl poly(meth)acrylate, ethyl poly(meth)acrylate, isopropyl poly(meth)acrylate, isobutyl poly(meth)acrylate, butyl poly(meth)acrylate, and poly(meth)acrylate. ) Hexyl acrylate, octyl poly(meth)acrylate, dodecyl poly(meth)acrylate, stearyl poly(meth)acrylate, 2-hydroxyethyl poly(meth)acrylate, poly(meth)acrylic acid, poly(meth) ) Benzyl acrylate, glycidyl poly(meth)acrylate, dimethylaminopropyl poly(meth)acrylate, and copolymers of the monomers constituting these resins.
Copolymers with other vinyl monomers are also preferably used. Examples thereof include poly(meth)acrylate-polystyrene copolymers, poly(meth)acrylate-acrylonitrile copolymers, and poly(meth)acrylate-butyl-acrylonitrile-styrene copolymers.
These may be used alone or in combination of two or more.

The water concentration of the polymer constituting the binder used in the present invention is preferably 100 ppm (mass basis) or less.
Further, the polymer constituting the binder used in the present invention may be crystallized and dried, or the polymer solution may be used as it is. It is preferable that the amount of the metal-based catalyst (urethane-forming or polyester-forming catalyst = tin, titanium, bismuth) is small. The metal concentration in the copolymer is preferably 100 ppm (mass basis) or less.

The weight average molecular weight of the polymer constituting the binder used in the present invention is preferably 10,000 or more, more preferably 20,000 or more, still more preferably 50,000 or more. The upper limit is preferably 1,000,000 or less, more preferably 200,000 or less, still more preferably 100,000 or less.

The content of the binder in the solid electrolyte composition is 0.01% by mass at 100% by mass of the solid component, in consideration of the good interfacial resistance reduction property and its maintainability when used in an all-solid secondary battery. The above is preferable, 0.1% by mass or more is more preferable, and 1% by mass or more is further preferable. From the viewpoint of battery characteristics, the upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less.
In the present invention, the mass ratio [(mass of inorganic solid electrolyte+mass of active material)/mass of binder] of the total mass (total mass) of the inorganic solid electrolyte and the active material to the mass of the binder is 1,000 to 1 A range is preferred. This ratio is more preferably 500 to 2, and even more preferably 100 to 10.

(Dispersion medium)
The solid electrolyte composition of the present invention preferably contains a dispersion medium.
The dispersion medium may be any one as long as it can disperse each of the above components, and examples thereof include various organic solvents. Specific examples of the dispersion medium include the following.
Examples of the alcohol compound solvent include methyl alcohol, ethyl alcohol, 1-propyl alcohol, 2-propyl alcohol, 2-butanol, ethylene glycol, propylene glycol, glycerin, 1,6-hexanediol, cyclohexanediol, sorbitol, xylitol, and the like. Examples thereof include 2-methyl-2,4-pentanediol, 1,3-butanediol, and 1,4-butanediol.
As the ether compound solvent, 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, propylene glycol monomethyl ether, dipropylene Glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether, etc.), dialkyl ether (dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, etc.), cyclic ether (tetrahydrofuran, dioxane (1,2-, 1, (Including each isomer of 3- and 1,4-))).
Examples of the amide compound solvent include N,N-dimethylformamide, N-methyl-2-pyrrolidone, 2-pyrrolidinone, 1,3-dimethyl-2-imidazolidinone, 2-pyrrolidinone, ε-caprolactam, formamide, and N. -Methylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropanamide, hexamethylphosphoric triamide and the like can be mentioned.
Examples of the amino compound solvent include triethylamine, diisopropylethylamine, tributylamine and the like.
Examples of the ketone compound solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.
Examples of the aromatic compound solvent include benzene, toluene, xylene and the like.
Examples of the aliphatic compound solvent include hexane, heptane, octane, decane and the like.
Examples of the nitrile compound solvent include acetonitrile, propyronitrile, isobutyronitrile and the like.
Examples of the ester compound solvent include ethyl acetate, butyl acetate, propyl acetate, butyl butyrate, and butyl pentanoate.
Examples of the non-aqueous dispersion medium include the above aromatic compound solvents and aliphatic compound solvents.

In the present invention, among them, an amino compound solvent, an ether compound solvent, a ketone compound solvent, an aromatic compound solvent, an aliphatic compound solvent is preferable, an ether compound solvent, an aromatic compound solvent and an aliphatic compound solvent are more preferable, and dibutyl ether. , Toluene and heptane are particularly preferred. By selecting this combination, a functional group active to the sulfide-based inorganic solid electrolyte is not contained, so that the sulfide-based inorganic solid electrolyte can be stably handled, which is preferable.
The dispersion medium may be used alone or in combination of two or more.

In the present invention, the content of the dispersion medium in the solid electrolyte composition can be appropriately set in consideration of the balance between the viscosity of the solid electrolyte composition and the drying load. Generally, 20 to 99% by mass is preferable, 25 to 70% by mass is more preferable, and 30 to 60% by mass is particularly preferable in the solid electrolyte composition.

(Conductive agent)
The solid electrolyte composition of the present invention may optionally contain a conductive auxiliary agent used for improving the electronic conductivity of the active material, etc. As the conductive auxiliary agent, a general conductive auxiliary agent can be used. For example, electron conductive materials such as graphites such as natural graphite and artificial graphite, carbon blacks such as acetylene black, Ketjen black and furnace black, amorphous carbon such as needle coke, vapor grown carbon fibers and carbon nanotubes. It may be carbon fiber such as, carbonaceous material such as graphene or fullerene, metal powder such as copper and nickel, metal fiber, conductive polymer such as polyaniline, polypyrrole, polythiophene, polyacetylene and polyphenylene derivative. May be used. One of these may be used, or two or more may be used.
When the solid electrolyte composition of the present invention contains a conduction aid, the content of the conduction aid in the solid electrolyte composition is preferably 0 to 10% by mass.

(Lithium salt)
The solid electrolyte composition of the present invention also preferably contains a lithium salt.
As the lithium salt, a lithium salt that is usually used in products of this type is preferable and there is no particular limitation. Examples thereof include LiTFSI and the lithium salts described in paragraphs 0082 to 0085 of JP-A-2005-088486.

The content of the lithium salt is preferably 0 parts by mass or more and more preferably 5 parts by mass or more with respect to 100 parts by mass of the solid electrolyte. The upper limit is preferably 50 parts by mass or less, more preferably 20 parts by mass or less.

(Dispersant)
The solid electrolyte composition of the present invention may contain a dispersant. By adding the dispersant, even if the content of either the electrode active material or the inorganic solid electrolyte is high, the aggregation thereof can be suppressed and a uniform active material layer and solid electrolyte layer can be formed.
As the dispersant, those usually used in all solid state secondary batteries can be appropriately selected and used. For example, it is composed of a low molecular weight or oligomer having a molecular weight of 200 or more and less than 3000 and contains a functional group represented by the functional group group (I) and an alkyl group having 8 or more carbon atoms or an aryl group having 10 or more carbon atoms in the same molecule. Those are preferable.
Functional group (I): acidic group, group having basic nitrogen atom, (meth)acrylic group, (meth)acrylamide group, alkoxysilyl group, epoxy group, oxetanyl group, isocyanate group, cyano group, mercapto group and hydroxy Group (preferably acidic group, group having basic nitrogen atom, alkoxysilyl group, cyano group, mercapto group and hydroxy group, more preferably carboxy group, sulfonic acid group, cyano group, amino group and hydroxy group)
In the all solid state secondary battery of the present invention, when there is a layer containing a dispersant, the content of the dispersant in the layer is preferably 0.2 to 10% by mass.

(Preparation of solid electrolyte composition)
The solid electrolyte composition of the present invention can be produced by mixing or adding an inorganic solid electrolyte and a specific additive, and optionally other components. For example, it can be produced by mixing the above components using various mixers. The mixing conditions are not particularly limited, and examples thereof include a ball mill, a bead mill, a planetary mixer, a blade mixer, a roll mill, a kneader and a disc mill.
In the method for producing the solid electrolyte composition, the negative electrode active material, the specific additive and the dispersion medium are mixed (stirred) at 10 to 50° C. for 1 to 10 hours, and then the dispersion medium is distilled off and vacuum dried. It is preferable to include a step of coating the negative electrode active material with a specific additive. In the production method including this step, the solid electrolyte composition can be produced by mixing or adding the negative electrode active material and the inorganic solid electrolyte coated with the specific additive, and optionally other components.

[Sheet for solid-state secondary battery]
The sheet for all-solid-state secondary batteries of the present invention is a sheet used for all-solid-state secondary batteries, and includes various aspects depending on its use. For example, a sheet preferably used for a solid electrolyte layer (also referred to as a solid electrolyte sheet for all solid state secondary battery), a sheet preferably used for an electrode or a laminate of an electrode and a solid electrolyte layer (electrode sheet for all solid state secondary battery) Etc. In the present invention, these various sheets may be collectively referred to as an all-solid-state secondary battery sheet.

The sheet for all-solid-state secondary batteries used in the present invention is a sheet having a solid electrolyte layer or an active material layer (electrode layer) on a base material. The sheet for an all-solid secondary battery may have other layers as long as it has a base material and a solid electrolyte layer or an active material layer, but one having an active material layer is an all-solid secondary battery described later. It is classified as an electrode sheet for secondary batteries. Examples of the other layer include a protective layer, a current collector, and a coat layer (current collector, solid electrolyte layer, active material layer).
Examples of the solid electrolyte sheet for an all-solid secondary battery used in the present invention include a sheet having a solid electrolyte layer and a protective layer on a substrate in this order.
The base material is not particularly limited as long as it can support the solid electrolyte layer, and examples thereof include sheet materials (plate-like materials) such as the materials, organic materials, and inorganic materials described for the current collector. Examples of the organic material include various polymers, and specific examples thereof include polyethylene terephthalate, polypropylene, polyethylene, and cellulose. Examples of the inorganic material include glass and ceramics.

The configuration and layer thickness of the solid electrolyte layer of the sheet for all-solid secondary battery are the same as the configuration and layer thickness of the solid electrolyte layer described in the all-solid secondary battery of the present invention.
This sheet is obtained by forming (coating and drying) the solid electrolyte composition on a substrate (which may be via other layers) to form a solid electrolyte layer on the substrate.

The electrode sheet for an all-solid secondary battery of the present invention (also simply referred to as the “electrode sheet of the present invention”) is a metal as a current collector for forming an active material layer of the all-solid secondary battery of the present invention. It is an electrode sheet having an active material layer on a foil. 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, as well as a current collector, an active material layer and a solid electrolyte. A mode having a layer and an active material layer in this order is also included.
The constitution and layer thickness of each layer constituting the electrode sheet are the same as the constitution and layer thickness of each layer described in the all solid state secondary battery of the present invention.
The electrode sheet is obtained by forming (coating and drying) the solid electrolyte composition of the present invention containing an active material on a metal foil to form an active material layer on the metal foil.

[Manufacture of all-solid-state secondary battery and electrode sheet for all-solid-state secondary battery]
The all-solid secondary battery and the electrode sheet for the all-solid secondary battery can be manufactured by a conventional method. Specifically, an all-solid secondary battery and an electrode sheet for an all-solid secondary battery can be produced by forming the above layers using the solid electrolyte composition of the present invention. This will be described in detail below.

The all-solid secondary battery of the present invention is produced by a method including (intermediately) applying the solid electrolyte composition of the present invention onto a metal foil serving as a current collector, and forming (coating) a coating film. it can.
For example, a solid electrolyte composition containing a positive electrode active material is applied as a positive electrode material (composition for a positive electrode layer) onto a metal foil that is a positive electrode current collector to form a positive electrode active material layer, and an all-solid electrolyte layer is formed. A positive electrode sheet for a secondary battery is produced. Then, a solid electrolyte composition for forming a solid electrolyte layer is applied onto the positive electrode active material layer to form a solid electrolyte layer. Further, a solid electrolyte composition containing a negative electrode active material is applied as a negative electrode material (negative electrode layer composition) on the solid electrolyte layer to form a negative electrode active material layer. To obtain an all-solid secondary battery having a structure in which a solid electrolyte layer is sandwiched between a positive electrode active material layer and a negative electrode active material layer by stacking a negative electrode current collector (metal foil) on the negative electrode active material layer. You can If necessary, this can be enclosed in a housing to form a desired all-solid-state secondary battery.
Further, the formation method of each layer is reversed, and a negative electrode active material layer, a solid electrolyte layer, and a positive electrode active material layer are formed on the negative electrode current collector, and the positive electrode current collector is stacked to manufacture an all-solid secondary battery. You can also do it.

Another method is as follows. That is, the positive electrode sheet for all solid state secondary batteries is produced as described above. Further, a solid electrolyte composition containing a negative electrode active material is applied as a negative electrode material (a composition for a negative electrode layer) onto a metal foil which is a negative electrode current collector to form a negative electrode active material layer. A negative electrode sheet for a secondary battery is produced. Then, the solid electrolyte layer is formed on one of the active material layers of these sheets as described above. Further, the other of the positive electrode sheet for all-solid secondary battery and the negative electrode sheet for all-solid secondary battery is laminated on the solid electrolyte layer so that the solid electrolyte layer and the active material layer are in contact with each other. In this way, the all solid state secondary battery can be manufactured.
The following method can be given as another method. That is, as described above, the positive electrode sheet for all solid state secondary batteries and the negative electrode sheet for all solid state secondary batteries are produced. Separately from this, the solid electrolyte composition is applied onto a substrate to prepare a solid electrolyte sheet for an all-solid secondary battery including a solid electrolyte layer. Further, the positive electrode sheet for all-solid secondary battery and the negative electrode sheet for all-solid secondary battery are laminated so as to sandwich the solid electrolyte layer peeled from the base material. In this way, the all solid state secondary battery can be manufactured.

An all-solid-state secondary battery can also be manufactured by a combination of the above forming methods. For example, the positive electrode sheet for all-solid secondary batteries, the negative electrode sheet for all-solid secondary batteries, and the solid electrolyte sheet for all-solid secondary batteries are each produced as mentioned above. Then, after stacking the solid electrolyte layer peeled from the substrate on the negative electrode sheet for all-solid secondary battery, it is possible to produce an all-solid secondary battery by laminating with the positive electrode sheet for all-solid secondary battery it can. In this method, the solid electrolyte layer may be laminated on the positive electrode sheet for the all-solid secondary battery and laminated with the negative electrode sheet for the all-solid secondary battery.

(Formation of each layer (deposition))
The method for applying the solid electrolyte composition is not particularly limited and can be appropriately selected. Examples thereof include coating (preferably wet coating), spray coating, spin coating, dip coating, slit coating, stripe coating, and bar coating.
At this time, the solid electrolyte composition may be subjected to a drying treatment after coating, or may be subjected to a multilayer treatment and then drying treatment. The drying temperature is not particularly limited. The lower limit is preferably 30°C or higher, more preferably 60°C or higher, even more preferably 80°C or higher. The upper limit is preferably 300°C or lower, more preferably 250°C or lower, and further preferably 200°C or lower. By heating in such a temperature range, the dispersion medium can be removed and a solid state can be obtained. It is also preferable because the temperature is not raised too high and each member of the all solid state secondary battery is not damaged. As a result, in the all-solid-state secondary battery, excellent overall performance can be obtained, and good binding properties and good ionic conductivity can be obtained even without pressure.

It is preferable to pressurize each layer or the all-solid-state secondary battery after producing the applied solid electrolyte composition or the all-solid-state secondary battery. Further, it is also preferable to apply pressure in a state where each layer is laminated. Examples of the pressurizing method include a hydraulic cylinder press machine and the like. The pressing force is not particularly limited and is generally preferably in the range of 50 to 1500 MPa.
Further, the applied solid electrolyte composition may be heated at the same time as pressurization. The heating temperature is not particularly limited and is generally in the range of 30 to 300°C. It is also possible to press at a temperature higher than the glass transition temperature of the inorganic solid electrolyte. On the other hand, when the inorganic solid electrolyte and the binder coexist, it is possible to press at a temperature higher than the glass transition temperature of the polymer forming the binder. However, generally, the temperature does not exceed the melting point of the polymer.
The pressurization may be performed in a state where the coating solvent or dispersion medium is dried in advance, or may be performed in a state where the solvent or dispersion medium remains.

The atmosphere during pressurization is not particularly limited, and may be under air, under dry air (dew point −20° C. or lower), in an inert gas (eg, argon gas, helium gas, nitrogen gas).
The pressing time may be short time (for example, within several hours) and high pressure may be applied, or long time (one day or more) and medium pressure may be applied. Other than the sheet for all-solid-state secondary batteries, for example, in the case of all-solid-state secondary batteries, a retainer (screw tightening pressure, etc.) for all-solid-state secondary batteries can be used in order to keep applying a moderate pressure.
The pressing pressure may be uniform or different with respect to the pressed portion such as the sheet surface.
The pressing pressure can be changed according to the area and film thickness of the pressed portion. It is also possible to change the same site stepwise with different pressures.
The pressed surface may be smooth or roughened.

(Initialization)
The all-solid-state secondary battery manufactured as described above is preferably initialized after manufacturing or before use. The initialization is not particularly limited, and can be performed, for example, by performing initial charge/discharge in a state where the press pressure is increased, and then releasing the pressure until it becomes a general working pressure of the all solid state secondary battery.

[Applications of all solid state secondary battery]
The all-solid secondary battery of the present invention can be applied to various uses. The application mode is not particularly limited. For example, when it is mounted on an electronic device, for example, a notebook computer, a pen input computer, a mobile computer, an electronic book player, a mobile phone, a cordless phone handset, a pager, a handy terminal, a mobile fax, a mobile phone. Examples include copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, mini disk, electric shaver, transceiver, electronic organizer, calculator, portable tape recorder, radio, backup power supply and memory card. Other consumer products include automobiles, electric vehicles, motors, lighting equipment, toys, game machines, road conditioners, watches, strobes, cameras and medical equipment (pacemakers, hearing aids, shoulder massagers, etc.), and the like. Further, it can be used for various munitions and for space. It can also be combined with a solar cell.

Above all, it is preferably applied to applications requiring high capacity and high rate discharge characteristics. For example, in power storage equipment and the like, which is expected to have a large capacity in the future, high safety is essential and further compatibility of battery performance is required. In addition, an electric vehicle or the like is equipped with a high-capacity secondary battery and is expected to be used for daily charging at home. Therefore, further safety against overcharging is required. According to the present invention, it is possible to suitably respond to such a usage pattern and to exhibit its excellent effects.

The all-solid-state secondary battery refers to a secondary battery in which the positive electrode, the negative electrode, and the electrolyte are all solid. In other words, it is distinguished from an electrolytic solution type secondary battery in which a carbonate-based solvent is used as the electrolyte. Among these, the present invention is premised on an inorganic all solid state secondary battery. The all-solid-state secondary battery includes an organic (polymer) all-solid-state secondary battery that uses a polymer compound such as polyethylene oxide as an electrolyte, and an inorganic all-solid-state secondary battery that uses the above Li-PS glass. It is divided into. The application of the polymer compound to the inorganic all-solid secondary battery is not hindered, and the polymer compound can be applied as the binder particles of the positive electrode active material, the negative electrode active material, and the inorganic solid electrolyte particles.
The inorganic solid electrolyte is distinguished from the above-mentioned electrolyte (polymer electrolyte) using a polymer compound such as polyethylene oxide as an ion conductive medium, and the inorganic compound serves as an ion conductive medium. As a specific example, the above-mentioned Li-P-S based glass can be mentioned. The inorganic solid electrolyte itself does not release cations (Li ions) but exhibits an ion transport function. On the other hand, a material that is added to the electrolytic solution or the solid electrolyte layer and serves as a supply source of ions that release cations (Li ions) may be referred to as an electrolyte, but is distinguished from the above-described electrolyte as an ion transport material. When it does, it is called the "electrolyte salt" or "supporting electrolyte". Examples of the electrolyte salt include LiTFSI (lithium bistrifluoromethanesulfonyl imide).
In the present invention, the term "composition" means a mixture in which two or more components are uniformly mixed. However, it is sufficient that the uniformity is substantially maintained, and a part of the particles may be aggregated or unevenly distributed within a range in which a desired effect is obtained. Further, particularly when referring to a solid electrolyte composition, it basically refers to a composition (typically a paste) that is a material for forming a solid electrolyte layer and the like, and an electrolyte layer and the like formed by curing the above composition. Is not included in this.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is not limited to this. In the following examples, "parts" and "%" representing compositions are based on mass unless otherwise specified. In addition, "-" used in the table means that it does not have the composition of the row.

(Exemplified compound)
-Synthesis-
Among the above-exemplified compounds listed in the column of additives shown in Tables 1 to 3 below, examples of synthesis of those prepared by synthesis are shown below.
AA1-2
It was synthesized by reacting dichloroethylene carbonate with potassium fluoride.
AA1-5
It was synthesized by reacting 3,3,3-trifluoropropane-1,2-diol and dimethyl carbonate under basic conditions with reference to US Pat. No. 6,180,800.
AA1-6
It was synthesized by reacting chloromethylethylene carbonate (CAS No. 2463-45-8) with potassium fluoride.
AA1-13
It was synthesized by reacting chloroethylene carbonate with potassium iodide.
BB1-2
It was synthesized by reacting 1,3-propanediol and thionyl chloride.
BB1-3
It was synthesized by reacting 1,2-propanediol and thionyl chloride.
BB3-1
It was synthesized by reacting thietane with hydrogen peroxide in acetic acid.
BB3-5
It was synthesized by reacting pentamethylene sulphide with potassium permanganate in water/methylene chloride.

-Commercial item-
Commercially available products of the above-exemplified compounds described in the columns of additives shown in Tables 1 to 3 below are shown below.
AA1-1
Tokyo Chemical Industry 4-fluoro-1,3,-dioxolan-2-one
AA1-8
Tokyo Chemical Industry Co., Ltd. Bis(2,2,2-trifluoroethyl)carbonate
BB1-1
Kishida Chemical's Ethylene Sulfite
BB1-4
Kishida Chemical Co., Ltd. Dimethyl sulfone
BB1-5
Tokyo Chemical Industry Co., Ltd. Din-proper sulfite
BB2-1
Aldrich's 1,3,2-Dioxathiolane 2,2-dioxide
BB2-3
Kishida Chemical Co. Propane Sultone
BB2-4
Wako Pure Chemical Industries 2,4-Butanesultone
BB2-6
Kishida Chemical's Methanesulfonic acid methyl ester
BB2-7
KENSIDA CHEMICAL CO., LTD. Benzensulfonic acid methyl ester
BB3-2
Sulfolane manufactured by Kishida Chemical Co., Ltd.
BB3-3
Kishida Chemical Co., Ltd. 3-Methyl sulfolane
BB3-7
Kishida Chemical Co., Ltd. Dimethyl sulfone
BB3-8
Kissida Chemical's Ethylhtyl sulphone
BB3-9
Diphenyl Sulfone manufactured by Kishida Chemical Co., Ltd.

(Additives other than the exemplified compounds)
The eX-1 described in the column of additives shown in Tables 1 to 3 below is a mixture of vinylene carbonate and benzoyl peroxide added to a toluene solution with reference to JP-A-2002-42876, and the mixture is stirred at 60° C. for 20 hours. Then, it is a polymer of vinylene carbonate synthesized by distilling off the solvent.
In addition, eX-2 is ethylene carbonate.

(Modification of negative electrode active material)
In a 300 mL three-necked flask, 10 g of graphite as a negative electrode active material, 0.1 g of Exemplified compound (AA1-1) (additive in Table 3 below), and 90 mL of tetrahydrofuran as a dispersion solvent were charged, and a stirrer was used at 25° C. for 2 hours. Stirring was performed. Then, the dispersion solvent was distilled off, and vacuum drying was performed to obtain a negative electrode active material (NA1) modified with the exemplary compound (AA1-1).
Similarly to the negative electrode active material (NA1), a negative electrode active material (NB1) modified with the exemplary compound (BB1-1) and a negative electrode active material (NB2) modified with the exemplary compound (BB2-3) were prepared.

(Synthesis of sulfide-based inorganic solid electrolyte)
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) in a glove box under an argon atmosphere (dew point −70° C.). , Purity >99%) 3.90 g were weighed and 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 set to Li ₂ S:P ₂ S ₅ =75:25 in terms of molar ratio.
66 g of zirconia beads having a diameter of 5 mm was placed in a zirconia 45 mL container (manufactured by Fritsch), and the entire mixture of the above lithium sulfide and diphosphorus pentasulfide was placed therein, and the container was completely sealed under an argon atmosphere. A sulfide-based inorganic solid electrolyte of yellow powder is obtained by setting the container in a planetary ball mill P-7 (trade name, manufactured by Fritsch) manufactured by Fritsch Co., and performing mechanical milling at a temperature of 25° C. and a rotation speed of 510 rpm for 20 hours. (Li-P-S glass, sometimes expressed as L-P-S.) 6.20 g was obtained.

<Preparation of solid electrolyte composition>
180 zirconia beads having a diameter of 5 mm were placed in a zirconia 45 mL container (manufactured by Fritsch), 9.3 g of the sulfide-based inorganic solid electrolyte Li-P-S-based glass synthesized above, and PVdF-HFP (polyfluoride) as a binder. 0.7 g of vinylidene hexafluoropropylene copolymer (manufactured by Arkema), 15 g of dibutyl ether as a dispersion medium, and 0.1 g of Exemplified Compound (AA1-1) (additive in Table 1 below) were added. Was set in a planetary ball mill P-7 (trade name, manufactured by Fritsch Co.), and stirring was continued for 2 hours at a temperature of 25° C. and a rotation speed of 300 rpm, thus preparing a solid electrolyte composition (SS-1). ..
Solid electrolyte compositions shown in the following Table 1 other than the solid electrolyte composition (SS-1) were prepared in the same manner as the solid electrolyte composition (SS-1) except that the composition was changed as shown in Table 1 below.

<Note of table>
All additions are in "grams (g)".

<Preparation of positive electrode layer composition (SA-1)>
180 zirconia beads having a diameter of 5 mm were placed in a zirconia 45 mL container (manufactured by Fritsche), and 1.9 g of the above-synthesized Li-P-S-based glass, exemplary compound (AA1-1) (additives in Table 2 below) ) 0.1 g, PVdF-HFP as a binder 0.15 g, and toluene as a dispersion medium 20 g. After that, this container was set in a planetary ball mill P-7 (manufactured by Fritsch) and stirred at a temperature of 25° C. and a rotation speed of 300 rpm for 2 hours, and then 7.9 g of NMC (manufactured by Nippon Kagaku Kogyo) as an active material. The mixture was placed in a container, the container was set again on the planetary ball mill P-7, and stirring was continued for 15 minutes at a temperature of 25° C. and a rotation speed of 200 rpm to obtain a positive electrode layer composition (SA-1).
The composition for the positive electrode layer shown in the following Table 2 other than the composition for the positive electrode layer (SA-1) was obtained in the same manner as the composition for the positive electrode layer (SA-1) except that the composition was changed as shown in Table 2 below. Prepared.

<Note of table>
All additions are in "grams (g)".
NMC: Li(Ni _1/3 Mn _1/3 Co _1/3 )O ₂ nickel, manganese, lithium cobalt oxide (Nippon Kagaku Kogyo)
LCO: LiCoO ₂ (lithium cobalt oxide)
NCA: LiNi _0.85 Co _0.10 Al _0.05 O ₂ (nickel cobalt aluminum aluminate)

<Preparation of composition for negative electrode layer>
180 pieces of zirconia beads having a diameter of 5 mm were placed in a zirconia 45 mL container (manufactured by Fritsche), 4 g of the Li-P-S based glass synthesized above, 0.2 g of PVdF-HFP as a binder, and an exemplified compound (AA1-1). ) (Additive of Table 3 below) 0.01 g, and toluene 20 g as a dispersion medium. Then, this container was set in a planetary ball mill P-7 (manufactured by Fritsch) and stirred at a temperature of 25° C. and a rotation speed of 300 rpm for 2 hours. Thereafter, 6 g of graphite as an active material was charged into a container, the container was set again in a planetary ball mill P-7, and stirring was continued for 15 minutes at a temperature of 25° C. and a rotation speed of 200 rpm to prepare a negative electrode layer composition (SB-1). Got
A positive electrode layer composition shown in the following Table 3 other than the positive electrode layer composition (SB-1) was prepared in the same manner as the positive electrode layer composition (SB-1) except that the composition was changed as shown in Table 3 below. Prepared.

<Note of table>
-The addition amount is all "gram (g)".
NA1, NB1 and NB2: the negative electrode active material (NA1) modified with the exemplary compound (AA1-1), the negative electrode active material (NB1) modified with the exemplary compound (BB1-1) and the exemplary compound (prepared above. A negative electrode active material (NB2) modified with BB2-3) was prepared.
In the negative electrode layer compositions (SB'-1) to (SB'-3), the amount of the negative electrode active material added is the total amount of the graphite and the additive coating the graphite.

<Preparation of electrode sheet for all solid state secondary battery>
The positive electrode layer composition (SA-1) prepared above was applied onto an aluminum foil (current collector) having a thickness of 20 μm with an applicator (trade name: SA-201 Baker type applicator, manufactured by Tester Sangyo Co., Ltd.), and 80 After heating at 0°C for 1 hour, it was further heated at 110°C for 1 hour to dry the positive electrode layer composition. Then, using a heat press machine, it pressurized (180 MPa, 1 minute), heating (120 degreeC), and produced the positive electrode sheet for all solid secondary batteries which has a laminated structure of a positive electrode active material layer/aluminum foil. The thickness of the positive electrode active material layer was 90 μm.
Then, on the obtained positive electrode active material layer, the solid electrolyte composition (eS-1) prepared above was applied by the above-mentioned Baker type applicator, heated at 80°C for 1 hour, and further heated at 100°C for 1 hour. Then, a solid electrolyte layer having a thickness of 50 μm was formed.
Then, on the obtained solid electrolyte layer, the composition for a negative electrode (eB-1) prepared above was applied by the above-mentioned Baker type applicator, heated at 80°C for 1 hour, and further heated at 110°C for 1 hour. Then, a negative electrode active material layer having a thickness of 100 μm was formed. A copper foil having a thickness of 20 μm was placed on the negative electrode active material layer, and pressed using a heat press while heating at 120° C. (600 MPa, 1 minute) to prepare an electrode sheet for an all-solid secondary battery.

<Preparation of all solid state secondary battery>
The electrode sheet for an all-solid secondary battery obtained above was cut into a disk shape having a diameter of 14.5 mm. The electrode sheet for an all-solid-state secondary battery with a diameter of 14.5 mm cut out into a diameter of 14.5 mm is put into a stainless steel 2032 type coin case 11 with a spacer and a washer incorporated therein, and the coin case 11 is caulked, as shown in FIG. The all-solid secondary battery of Example 1-1 shown was produced.
The all-solid-state secondary battery manufactured in this way has the layer structure shown in FIG.
An all-solid secondary battery shown in Table 4 below other than that of Example 1-1 was produced in the same manner as the all-solid secondary battery of Example 1-1, except that the layer structure was as shown in Table 4 below.

<Battery characteristics test>
The following solid-state secondary battery (hereinafter, also simply referred to as “battery”) manufactured as described above was subjected to the following battery characteristic test.

-Test Example 1. 4.2V cycle test −
Using the battery produced above, charging/discharging at 4.2V-3.0V was repeated four times at 30° C. with a charging current value of 0.35 mA and a discharging current value of 0.7 mA.
Thereafter, as a cycle test, a test in which charging/discharging of 4.2V to 3.0V was repeated under a condition of a charging/discharging current value of 0.7 mA under a 30° C. environment was carried out.
In this cycle test, the number of cycles at which the discharge capacity was 80% when the discharge capacity at the first cycle was 100% was evaluated. The number of cycles is shown in Table 4 below.
By this test, it is possible to observe battery deterioration caused by a solid electrolyte side reaction when the battery is operated at 4.2V.

-Test example 2. 10°C-4.2V cycle test-
Using the battery produced above, charging/discharging at 4.2V-3.0V was repeated four times at 30° C. with a charging current value of 0.35 mA and a discharging current value of 0.7 mA. Using this battery, charging/discharging was performed at a charging current value of 0.35 mA and a discharging current value of 7 mA, and the discharge capacity was measured.
Thereafter, as a cycle test, a test in which charge/discharge at 4.2 V to 3.0 V was repeated 50 times under a condition of a charge/discharge current value of 0.7 mA under a 10° C. environment was carried out. Then, charging/discharging was performed at a charging current value of 0.35 mA and a discharging current value of 7 mA, and the discharge capacity after the cycle test was measured.
The following formula was used to evaluate the capacity retention rate during discharge before and after the 10° C. cycle test. In Table 4 below, the discharge capacity retention rate (%) is described by omitting the unit “%”.

Discharge capacity maintenance rate (%) = discharge capacity at 2C current value after 50 cycles
/Discharge capacity at 2C current value before cycle test×100

By this test, it is possible to observe battery deterioration due to a solid electrolyte side reaction when the battery is operated at 10° C. (low temperature).

<Confirmation of film formation>
The cross section of the contact surface between the sulfide-based inorganic solid electrolyte and the active material was adjusted with a focused ion beam scanning electron microscope (FIB-SEM) (Carl Zdeiss trade name: Auriga). Composition analysis was performed on this cross section by energy dispersive X-ray spectroscopy (TEM-EDX) to confirm the element distribution (distribution of C, O, halogen and S) at the sulfide-based inorganic solid electrolyte-active material interface. did.
In Examples 1-1 to 1-44 of Table 4 below, C, O and halogen, or C, S and O were observed on the surface of the sulfide-based inorganic solid electrolyte-active material interface, and the sulfide-based inorganic solid electrolyte It was confirmed that a film was formed on the surface.
On the other hand, in Comparative Examples 1-1 to 1-9 in Table 4 below, elements derived from specific additives such as C and O were not observed at the sulfide-based inorganic solid electrolyte-active material interface, and the sulfide-based inorganic solid It was confirmed that no film was formed on the surface of the electrolyte.

From Table 4, the solid electrolyte composition of the present invention is used to form an all-solid secondary battery in which any one of the positive electrode active material layer, the solid electrolyte layer and the negative electrode active material layer in the all-solid secondary battery is formed. Test Example 1. And 2. In all cases, good results were shown. It can be seen that the all-solid secondary battery of the present invention exhibits excellent cycle characteristics even at low temperature (10° C.) operation.
On the other hand, the all-solid-state secondary battery of the comparative example, in which none of the layers in the all-solid-state secondary battery contains a specific additive, suppresses battery deterioration during 4.2V battery operation and low-temperature operation cycle. None of the properties were satisfactory.

DESCRIPTION OF SYMBOLS 1 Negative electrode current collector 2 Negative electrode active material layer 3 Solid electrolyte layer 4 Positive electrode active material layer 5 Positive electrode current collector 6 Operating part 10 All solid state secondary battery 11 Coin case 12 Sheet for all solid state secondary battery 13 Cell for cycle characteristic evaluation (Coin battery)

Claims (10)

A solid electrolyte composition containing a sulfide-based inorganic solid electrolyte having ion conductivity of a metal belonging to Group 1 or 2 of the periodic table,
A compound having a C=O bond forming a film on the surface of the sulfide-based inorganic solid electrolyte by an electrochemical action, or a compound having an S=O bond forming a film on the surface of the sulfide-based inorganic solid electrolyte by an electrochemical action. containing the C = compound having O bonds Ri compound der described below (a), a solid electrolyte composition is a compound according the compound having a S = O bonds in the following (B).
(A) Carbonate compound having a carbonate group and a halogen atom in the molecule
(B) Sulfite compound, sulfonate compound or sulfone compound The carbonate compound is represented by the following general formula (A1), and the sulfite compound, the sulfonate compound and the sulfone compound are represented by the following general formulas (B1), (B2) and (B3), respectively. The solid electrolyte composition according to claim 1 .

In the general formula, R ^A1 , R ^B21 and R ^B22 each independently represent a monovalent substituent. R ^B3 represents a monovalent substituent bonded to a sulfur atom by a carbon atom. Multiple ^{R A1,} the plurality of ^{R B1} and a plurality of ^{R B3,} may be different be the same as each other, respectively, among the plurality of ^{R A1,} a plurality of ^{R B1 between, R B21} and ^{R B22,} and a plurality of Each R ^B3 may form a ring. At least one R ^A1 has at least one halogen atom. The solid electrolyte composition according to claim 1 or 2 , wherein each of the compound described in (A) and the compound described in (B) has a cyclic structure in the molecule. The compounds represented by the formulas (A1), (B1), (B2) and (B3) are respectively represented by the following formulas (A1-2), (B1-2), (B2-2) and The solid electrolyte composition according to claim 2 , which is a compound represented by each formula of (B3-2).

In the general formula (A1-2), α represents an atomic group necessary for forming a ring having 5 or more members, and the compound represented by the general formula (A1-2) has at least one halogen atom.
In the general formula (B1-2), β represents an atomic group necessary for forming a ring having 5 or more members.
In formula (B2-2), L ¹ represents -O- or an alkylene group. χ represents an atomic group necessary for forming a ring having 5 or more members.
In the general formula (B3-2), each L ² independently represents an alkylene group. δ represents an atomic group necessary for forming a ring having 4 or more members. Solid electrolyte composition according to any one of claims 1 to 4 containing an electrode active material. The solid electrolyte composition according to claim 5 , wherein the electrode active material is a negative electrode active material. Sheet for all-solid secondary battery having a layer of solid electrolyte composition according to the substrate in any one of claims 1-6. What is claimed is: 1. An all-solid-state secondary battery comprising a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer comprises: all-solid secondary battery which is a layer made of a solid electrolyte composition according to any one of clauses 1-6. A method for producing a sheet for an all-solid secondary battery, which comprises disposing the solid electrolyte composition according to any one of claims 1 to 7 on a substrate and forming a film from the substrate. An all-solid-state secondary battery manufacturing method for manufacturing an all-solid-state secondary battery through the manufacturing method according to claim 9 .

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