WO2013065738A2 - All-solid-state secondary battery - Google Patents

Abstract

　[Problem] To provide an all-solid-state secondary battery with an outstanding initial discharge capacity and high-temperature storage characteristics.　[Solution] This all-solid-state secondary battery comprises a positive electrode having a positive electrode active substance layer, a negative electrode having a negative active substance layer, and a solid-state electrolyte layer, and is characterized in that at least one layer selected from among the positive electrode active substance layer, the negative electrode active substance layer and the solid-state electrolyte layer contains an inorganic solid-state electrolyte and a polymer containing an alicyclic structure.　

Description

All solid state secondary battery

The present invention relates to an all solid state secondary battery such as an all solid state lithium ion secondary battery.

In recent years, secondary batteries such as lithium batteries have been used in various applications such as portable power terminals such as personal digital assistants and portable electronic devices, as well as small household power storage devices, motorcycles, electric vehicles, and hybrid electric vehicles. Has increased.

As the applications expand, further improvements in the safety of secondary batteries are required. In order to ensure safety, a method of preventing liquid leakage and a method of using an inorganic solid electrolyte instead of an organic solvent electrolyte having high flammability and extremely high ignition risk at the time of leakage are effective.

Patent Document 1 describes an all-solid secondary battery having an electrode layer containing a sulfide solid electrolyte material as an inorganic solid electrolyte and hydrogenated styrene-butadiene rubber as a binder.

JP 2011-134675 A

However, according to the study of the present inventors, it has been found that the battery characteristics such as the initial discharge capacity and the high temperature holding characteristic may be deteriorated in the all solid state secondary battery of Patent Document 1.

Therefore, the present invention has been made in view of the above problems, and an object thereof is to provide an all-solid-state secondary battery excellent in initial discharge capacity and high-temperature holding characteristics.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the reason why the battery characteristics such as the initial discharge capacity and high-temperature holding characteristics of the all-solid-state secondary battery are reduced is the carbon in the polymer used as the binder. -It was found that there was a carbon unsaturated bond. In the hydrogenated styrene-butadiene rubber described in Patent Document 1, it was found that the aromatic ring of the styrene unit remained in the polymer in a large amount without being hydrogenated. As a result of further investigations, the present inventors have found that the above problems can be solved by using a polymer having an alicyclic structure as a binder, and the present invention has been completed.

The gist of the present invention aimed at solving such problems is as follows.
[1] An all-solid secondary battery having a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, and a solid electrolyte layer,
An all-solid secondary battery, wherein at least one of a positive electrode active material layer, a negative electrode active material layer, or a solid electrolyte layer contains a polymer containing an alicyclic structure and an inorganic solid electrolyte.

[2] The all-solid-state secondary battery according to [1], wherein the alicyclic structure is a structure in which an aromatic ring is hydrogenated.

[3] A polymer containing the alicyclic structure is obtained by hydrogenating a copolymer of a vinyl aromatic monomer and another monomer copolymerizable with the monomer. A vinyl alicyclic hydrocarbon-based polymer,
The all solid state secondary battery according to [1] or [2], wherein 90% or more of all carbon-carbon unsaturated bonds in the copolymer are hydrogenated.

[4] The polymer block containing the alicyclic structure is a polymer block (A) mainly composed of a vinyl aromatic monomer unit obtained by hydrogenating a carbon-carbon unsaturated bond of an aromatic ring; Any one of [1] to [3], which is a hydrogenated block copolymer having a polymer block (B) mainly composed of a chain conjugated diene monomer unit obtained by hydrogenating a carbon-carbon unsaturated bond An all-solid-state secondary battery according to any one of the above.

[5] When the weight fraction of the polymer block (A) in the entire hydrogenated block copolymer is wA and the weight fraction of the polymer block (B) in the entire hydrogenated block copolymer is wB The all-solid secondary battery according to [4], wherein the ratio of wA to wB (wA: wB) is 20:80 to 60:40.

[6] The all-solid-state secondary battery according to any one of [1] to [5], wherein the polymer having an alicyclic structure has a weight average molecular weight of 30,000 to 200,000.

[7] The all-solid-state secondary battery according to any one of [1] to [6], wherein the inorganic solid electrolyte is a sulfide glass and / or sulfide glass ceramic made of Li ₂ S and P ₂ S _5. .

According to the present invention, the dispersibility of the inorganic solid electrolyte is improved by using a polymer containing an alicyclic structure. As a result, the coating property of the resulting slurry composition is improved, and an electrode active material layer and a solid electrolyte layer having excellent flexibility and strength can be obtained. The initial discharge capacity and high temperature of an all-solid secondary battery can be obtained. Holding characteristics are improved.

The all-solid-state secondary battery of the present invention has a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, and a solid electrolyte layer, and has a positive electrode active material layer, a negative electrode active material layer, or a solid electrolyte layer. At least one layer, preferably all layers, contains a polymer containing an alicyclic structure and an inorganic solid electrolyte.

Polymer containing an alicyclic structure In the present invention, a polymer containing an alicyclic structure (hereinafter, sometimes referred to as “alicyclic structure-containing polymer”) is heavy. It is a polymer containing an alicyclic structure in the repeating unit of the coalescence. Either the main chain or the side chain of the polymer may have an alicyclic structure, but those containing an alicyclic structure in the main chain are preferred from the viewpoint of the strength and heat resistance of the polymer.

The alicyclic structure is preferably a structure in which an aromatic ring is hydrogenated, specifically, a saturated cyclic hydrocarbon (cycloalkane) structure, an unsaturated cyclic hydrocarbon (cycloalkene) structure, and the like. From the viewpoint of thermal stability of the polymer, a cycloalkane structure is preferable.

The number of carbon atoms constituting the alicyclic structure is usually in the range of 4 to 30, preferably 5 to 20, and more preferably 6 to 15. When the number of carbon atoms is within this range, the resulting polymer has excellent heat resistance.

The ratio of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected depending on the intended use of the polymer, but is preferably 20 to 60% by weight, more preferably 25 to 25%. It is 55% by weight, particularly preferably 30 to 50% by weight. When the ratio of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer is within this range, the resulting polymer has excellent heat resistance. In addition, the remainder other than the repeating unit which has an alicyclic structure in an alicyclic structure containing polymer is suitably selected according to the intended purpose.

Specific examples of the alicyclic structure-containing polymer include (1) a norbornene polymer, (2) a monocyclic olefin polymer, (3) a cyclic conjugated diene polymer, and (4) a vinyl alicyclic polymer. Examples thereof include hydrocarbon polymers and hydrides of (1) to (4). Among these, norbornene-based polymers, cyclic conjugated diene-based polymers, vinyl alicyclic hydrocarbon-based polymers, and hydrides thereof are preferable from the viewpoint of heat resistance and strength of the obtained polymer. Polymers, vinyl alicyclic hydrocarbon polymers and their hydrides are more preferred, and vinyl alicyclic hydrocarbon polymers and their hydrides are particularly preferred.

(1) Norbornene-based polymer The norbornene-based polymer is obtained by polymerizing a norbornene-based monomer that is a monomer having a norbornene skeleton, and is obtained by ring-opening polymerization or by addition polymerization. Broadly divided into things.

As ring-opening polymerization, ring-opening polymers of norbornene monomers, ring-opening polymers of norbornene monomers and other monomers capable of ring-opening copolymerization, and hydrogens thereof. And the like. Examples of the polymers obtained by addition polymerization include addition polymers of norbornene monomers and addition polymers of norbornene monomers and other monomers copolymerizable therewith. Among these, a ring-opening polymer hydride of a norbornene-based monomer is preferable from the viewpoints of heat resistance and strength of the polymer.

Examples of norbornene monomers include bicyclo [2.2.1] hept-2-ene (common name: norbornene) and its derivatives (having substituents in the ring), tricyclo [4.3.0 ^1,6 . 1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene) and derivatives thereof, 7,8-benzotricyclo [4.3.0.1 ^2,5 ] dec-3-ene (common) Name: methanotetrahydrofluorene: 1,4-methano-1,4,4a, 9a-tetrahydrofluorene) and its derivatives, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene (common name: tetracyclododecene) and its derivatives.
Examples of the substituent include an alkyl group, an alkylene group, a vinyl group, an alkoxycarbonyl group, and an alkylidene group, and the norbornene-based monomer may have two or more of these. Specifically, 8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene, 8-ethylidene-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene and the like.
These norbornene monomers are used alone or in combination of two or more.

A ring-opening polymer of a norbornene-based monomer, or a ring-opening polymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization with a monomer component is a known ring-opening polymerization. It can be obtained by polymerization in the presence of a catalyst. As the ring-opening polymerization catalyst, for example, a catalyst comprising a metal halide such as ruthenium or osmium and a nitrate or acetylacetone compound and a reducing agent, or a metal halide or acetylacetone such as titanium, zirconium, tungsten or molybdenum A catalyst comprising a compound and an organoaluminum compound can be used.

Examples of other monomers capable of ring-opening copolymerization with norbornene monomers include monocyclic olefin monomers such as cyclohexene, cycloheptene, and cyclooctene.

The ring-opening polymer hydride of a norbornene-based monomer is usually obtained by adding a known hydrogenation catalyst containing a transition metal such as nickel or palladium to the polymerization solution of the ring-opening polymer and then adding a carbon-carbon unsaturated bond. Can be obtained by hydrogenation. As the hydrogenation catalyst, a catalyst containing nickel is preferable because it can prevent the polymer chain from being broken and can be hydrogenated at a low temperature and a low pressure.

An addition polymer of a norbornene monomer, or an addition polymer of a norbornene monomer and another monomer copolymerizable therewith, these monomers are added to a known addition polymerization catalyst, for example, It can be obtained by polymerization using a catalyst comprising a titanium, zirconium or vanadium compound and an organoaluminum compound.

Examples of other monomers that can be addition copolymerized with norbornene monomers include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, and the like. A cycloolefin such as cyclobutene, cyclopentene, cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7-methano-1H-indene, and derivatives thereof; 1,4-hexadiene, 4-methyl Non-conjugated dienes such as 1,4-hexadiene, 5-methyl-1,4-hexadiene, 1,7-octadiene; and the like. Among these, α-olefin is preferable, and ethylene is particularly preferable.

These other monomers capable of addition copolymerization with norbornene monomers can be used alone or in combination of two or more. In the case of addition copolymerization of a norbornene monomer and another monomer capable of addition copolymerization, other units capable of addition copolymerization with the structural unit derived from the norbornene monomer in the addition polymer. Appropriately so that the ratio with the structural unit derived from the monomer is usually in the range of 30:70 to 99: 1, preferably 50:50 to 97: 3, more preferably 70:30 to 95: 5 by weight. Selected.

(2) Monocyclic cyclic olefin polymer As the monocyclic olefin polymer, for example, an addition polymer of a monocyclic olefin monomer such as cyclohexene, cycloheptene, or cyclooctene can be used. it can.

(3) Cyclic conjugated diene polymer As the cyclic conjugated diene polymer, for example, a polymer obtained by subjecting a cyclic conjugated diene monomer such as cyclopentadiene or cyclohexadiene to 1,2- or 1,4-addition polymerization, and The hydride can be used.

(4) Vinyl alicyclic hydrocarbon-based polymer Examples of vinyl alicyclic hydrocarbon-based polymers include polymers of vinyl alicyclic hydrocarbon monomers such as vinylcyclohexene and vinylcyclohexane, and hydrogenated products thereof. Hydrides of aromatic ring moieties of polymers of vinyl aromatic monomers such as styrene and α-methylstyrene; vinyl alicyclic hydrocarbon monomers and vinyl aromatic monomers; A hydride of a copolymer with another monomer copolymerizable with the monomer; and the like. Among these, a hydride of a copolymer of a vinyl aromatic monomer and another monomer copolymerizable with the monomer is preferable, and the vinyl aromatic monomer and the monomer A hydride of a block copolymer with another monomer copolymerizable with the polymer is more preferable. Examples of the block copolymer include diblock, triblock, or more multiblock and gradient block copolymers, and are not particularly limited. In the present invention, the “block” refers to a segment in the block copolymer in which at least 30 monomer units having the same skeleton are linked.

Further, the alicyclic structure-containing polymer is a vinyl alicyclic carbonization obtained by hydrogenating a copolymer of a vinyl aromatic monomer and another monomer copolymerizable with the monomer. In the case of a hydrogen-based polymer, those obtained by hydrogenating 90% or more of all carbon-carbon unsaturated bonds in the copolymer are preferred, and 93% or more of all carbon-carbon unsaturated bonds are hydrogenated. Those obtained by hydrogenation are preferred, and those obtained by hydrogenating 95% or more of all the carbon-carbon unsaturated bonds are particularly preferred. By using such a polymer, the dispersibility of the resulting slurry composition can be improved, and the high-temperature retention characteristics of the all-solid secondary battery of the present invention can be improved. In the present invention, all carbon-carbon unsaturated bonds include main-chain and side-chain carbon-carbon unsaturated bonds and aromatic-ring carbon-carbon unsaturated bonds.

The hydride of the above block copolymer (hereinafter sometimes referred to as “block copolymer hydride”) is a vinyl aromatic monomer obtained by hydrogenating a carbon-carbon unsaturated bond of an aromatic ring. A hydrogenated block copolymer comprising a polymer block (A) having a unit as a main component and a polymer block (B) having a chain conjugated diene monomer unit having a hydrogenated carbon-carbon unsaturated bond as a main component. A polymer is preferred. By using such a polymer, the dispersibility of the resulting slurry composition can be improved.

Further, the hydride of the block copolymer is preferably a vinyl aromatic monomer unit (non-hydrogenated aromatic ring-containing monomer unit) in which the carbon-carbon unsaturated bond of the aromatic ring is not hydrogenated. Less than 5% by weight, more preferably 3 to 0% by weight. By using such a polymer, the high temperature retention characteristics of the all solid state secondary battery of the present invention can be improved.

In the present invention, the chain conjugated diene monomer is another monomer copolymerizable with a vinyl aromatic monomer, and specifically includes 1,3-butadiene, isoprene, 2,3- Examples include dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. Of these, 1,3-butadiene and isoprene are preferable, and isoprene is more preferable. The chain conjugated diene monomers can be used alone or in combination of two or more.

When the weight fraction of the polymer block (A) in the entire hydrogenated block copolymer is wA, and the weight fraction of the polymer block (B) in the entire hydrogenated block copolymer is wB. The ratio of wA to wB (wA: wB) is preferably 20:80 to 60:40, more preferably 25:75 to 55:45, and particularly preferably 30:70 to 50:50. By using such a polymer, a coating film having excellent flexibility and high strength (for example, a positive electrode active material layer, a negative electrode active material layer, or a solid electrolyte layer) can be obtained.

Using the above monomers, the precursor of the polymer block (A) [polymer block before hydrogenation (A)] and the precursor of the polymer block (B) [polymer block before hydrogenation (B )] Is not particularly limited, and examples thereof include radical polymerization, anionic polymerization, cationic polymerization, coordination anionic polymerization, and coordination cationic polymerization. When a method in which radical polymerization, anion polymerization, cation polymerization, or the like is performed by living polymerization, particularly a method in which living anion polymerization is performed, a polymerization operation and a hydrogenation reaction in a post process are facilitated.

Polymerization is usually carried out in the presence of a polymerization initiator in a temperature range of 0 to 150 ° C., preferably 20 to 100 ° C., particularly preferably 10 to 80 ° C. In the case of living anionic polymerization, as a polymerization initiator, for example, monoorganolithium such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium; dilithiomethane, 1,4-diobane, 1, Polyfunctional organolithium compounds such as 4-dilithio-2-ethylcyclohexane can be used.

The polymerization reaction form may be any of solution polymerization, slurry polymerization, and the like, but if solution polymerization is used, the reaction heat can be easily removed. In this case, an inert solvent in which the polymer obtained in the production process of the precursor of the polymer block (A) and the production process of the precursor of the hydrogenated block copolymer (block copolymer before hydrogenation) are dissolved together. Is used. Examples of the inert solvent used include aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, isooctane; cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, decalin , Alicyclic hydrocarbons such as bicyclo [4.3.0] nonane and tricyclo [4.3.0.1 ^2,5 ] decane; aromatic hydrocarbons such as benzene and toluene. Among these, alicyclic hydrocarbons are preferable because they can be used as they are as an inert solvent for the hydrogenation reaction described later and the solubility of the hydrogenated block copolymer is good. These solvents may be used alone or in combination of two or more. The amount of these solvents used is usually 200 to 2000 parts by weight with respect to 100 parts by weight of all the monomers used.

The hydrogenated block copolymer is obtained by hydrogenating the carbon-carbon unsaturated bond of the aromatic ring in the precursor of the polymer block (A) and the carbon-carbon unsaturated bond in the precursor of the polymer block (B). can get. As long as the desired effect of the present invention is obtained, a part of the carbon-carbon unsaturated bond may remain in the polymer block (A) and the polymer block (B) in any form.

The mode of the block copolymer subjected to hydrogenation is not particularly limited, and is a [(A)-(B)] type diblock copolymer, [(A)-(B)-(A)] type. And a block copolymer having a larger number of blocks.

The method for producing the hydrogenated block copolymer is not particularly limited. For example, a vinyl aromatic monomer is subjected to addition polymerization to obtain a precursor of the polymer block (A) by a method of obtaining the precursor of the polymer block (A) and the precursor of the polymer block (B). Subsequently, the chain conjugated diene monomer is addition-polymerized to obtain a hydrogenated block copolymer precursor having a polymer block (A) precursor and a polymer block (B) precursor. Thereafter, a method for producing a hydrogenated block copolymer having a polymer block (A) and a polymer block (B) by hydrogenating unsaturated bonds such as aromatic rings of the precursor of the hydrogenated block copolymer. Can be mentioned.

The hydrogenation method of unsaturated bonds, reaction mode, etc. are not particularly limited and may be carried out according to a known method, but a hydrogenation method that can increase the hydrogenation rate and has little polymer chain scission reaction is preferred. Examples of such a preferable hydrogenation method include a method using a catalyst containing at least one metal selected from nickel, cobalt, iron, titanium, rhodium, palladium, platinum, ruthenium, rhenium and the like. As the hydrogenation catalyst, it is preferable to use a catalyst containing nickel because it prevents the polymer chain from being broken and can be hydrogenated at low temperature and low pressure. As the hydrogenation catalyst, either a heterogeneous catalyst or a homogeneous catalyst can be used, and the hydrogenation reaction is preferably carried out in an organic solvent.

The heterogeneous catalyst can be used in the form of a metal or a metal compound or supported on a suitable carrier. Examples of the carrier include activated carbon, silica, alumina, calcium carbonate, titania, magnesia, zirconia, diatomaceous earth, silicon carbide, calcium fluoride and the like. The amount of the catalyst supported is usually 0.1 to 60% by weight, preferably 1 to 50% by weight. As the supported catalyst, for example, a catalyst having a specific surface area of 100 to 500 m ² / g and an average pore diameter of 100 to 1000 mm, preferably 200 to 500 mm is preferable. The value of the specific surface area is a value calculated by measuring the nitrogen adsorption amount and using the BET equation, and the value of the average pore diameter is a value measured by a mercury intrusion method.

Examples of homogeneous catalysts include catalysts obtained by combining nickel, cobalt, titanium, or iron compounds with organometallic compounds (eg, organoaluminum compounds, organolithium compounds); transition metals such as rhodium, palladium, platinum, ruthenium, rhenium, etc. Complex catalysts; organometallic complex catalysts as described below; and the like can be used. As the nickel, cobalt, titanium, or iron compound, for example, various metal acetylacetonate compounds, carboxylates, cyclopentadienyl compounds, and the like are used. Examples of the organoaluminum compound include alkylaluminums such as triethylaluminum and triisobutylaluminum; aluminum halides such as diethylaluminum chloride and ethylaluminum dichloride; alkylaluminum hydrides such as diisobutylaluminum hydride and the like.

Examples of organometallic complex catalysts include transition metal complexes such as dihydrido-tetrakis (triphenylphosphine) ruthenium, dihydrido-tetrakis (triphenylphosphine) iron, bis (cyclooctadiene) nickel, and bis (cyclopentadienyl) nickel. Is mentioned.

These hydrogenation catalysts may be used alone or in combination of two or more. The amount of the hydrogenation catalyst used is usually 0.01 to 100 parts by weight, preferably 0.05 to 50 parts by weight, more preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the polymer.

When the hydrogenation reaction temperature is usually from 10 to 250 ° C., preferably from 50 to 200 ° C., more preferably from 80 to 180 ° C., the hydrogenation rate increases and molecular cleavage also decreases. The hydrogen pressure is a gauge pressure, usually 0.1 to 30 MPa, preferably 1 to 20 MPa, more preferably 2 to 10 MPa, resulting in a high hydrogenation rate, reduced molecular chain breakage, and excellent operability.

The hydrogenation rate of the hydrogenation reaction is determined by ¹ H-NMR, both of the hydrogenation rate of the carbon-carbon unsaturated bond of the main chain and the side chain, and the hydrogenation rate of the carbon-carbon unsaturated bond of the aromatic ring However, it is preferably 90% or more, more preferably 93% or more, and still more preferably 95% or more.
The hydrogenation rate of the carbon-carbon unsaturated bond of the main chain and side chain of the block copolymer hydride, and the hydrogenation rate of the carbon-carbon unsaturated bond of the aromatic ring were ¹ H- before and after the hydrogenation reaction. Measure the NMR spectrum and calculate based on the decrease in the integrated value of the signal corresponding to the carbon-carbon unsaturated bond in the main chain and side chain part and the carbon-carbon unsaturated bond in the aromatic ring before and after the hydrogenation reaction. be able to.

The block copolymer hydride is obtained from the reaction solution after removing the hydrogenation catalyst and / or the polymerization catalyst from the reaction solution containing the block copolymer hydride, for example, by filtration, centrifugation, or the like.

The method for obtaining the block copolymer hydride from the reaction solution is not particularly limited. For example, the steam coagulation method in which the solvent is removed from the solution in which the block copolymer hydride is dissolved by steam stripping, under reduced pressure heating. It can be obtained by a known method such as a direct desolvation method for removing the solvent or a coagulation method in which the solution is poured into a poor solvent of the block copolymer hydride to precipitate and solidify.

The molecular weight of the alicyclic structure-containing polymer used in the present invention is appropriately selected according to the purpose of use, but is a gel permeation chromatograph of a cyclohexane solution (a toluene solution when the polymer resin does not dissolve). The weight average molecular weight (Mw) in terms of polystyrene measured in (1) is usually 10,000 or more, preferably 30,000 to 200,000, more preferably 40,000 to 150,000, particularly preferably 50,000 to 100,000. When the molecular weight of the alicyclic structure-containing polymer is within the above range, a slurry composition with good coatability can be obtained.

The molecular weight distribution (Mw / Mn) of the alicyclic structure-containing polymer is not particularly limited, but is preferably in the range of 1 to 1.9, more preferably in the range of 1 to 1.6. A range of 4 is particularly preferable.
In the present invention, the molecular weight distribution (Mw / Mn) of the alicyclic structure-containing polymer is determined by gel permeation chromatography (hereinafter referred to as GPC) using a cyclohexane solution (a toluene solution when the polymer resin is not dissolved) as a solvent. ) Is a value (Mw / Mn) obtained by dividing the weight average molecular weight (Mw) by the polystyrene-equivalent number average molecular weight (Mn).

The melt mass flow rate (MFR) of the alicyclic structure-containing polymer may be appropriately selected according to the purpose of use of the polymer, but is preferably in the range of 2 to 30 g / 10 minutes, and preferably 3 to 20 g / 10. More preferably, it is in the range of 5 minutes, and particularly preferably in the range of 5 to 10 g / 10 minutes. When the MFR is in this range, a slurry composition having good coatability can be obtained. In the present invention, melt mass flow rate (MFR) is a value measured according to JIS K 6719; 1996 under conditions of a temperature of 230 ° C. and a load of 21.18 N.

The glass transition temperature (Tg) of the alicyclic structure-containing polymer used in the present invention may be appropriately selected according to the purpose of use, but is usually 50 to 200 ° C., preferably 70 to 180 ° C., particularly preferably. Is in the range of 90-150 ° C. When the Tg of the alicyclic structure-containing polymer is in the above range, a slurry composition having good coatability can be obtained, and the heat resistance of the polymer is highly balanced, which is preferable.
The glass transition temperature as used in the field of this invention is measured based on JISK7121; 1987.

The above alicyclic structure-containing polymers can be used alone or in combination of two or more.

(Inorganic solid electrolyte)
The inorganic solid electrolyte used in the present invention is not particularly limited as long as it has lithium ion conductivity, but preferably contains a crystalline inorganic lithium ion conductor or an amorphous inorganic lithium ion conductor.

Crystalline inorganic lithium ion conductors include Li ₃ N, LIICON (Li ₁₄ Zn (GeO ₄ ) ₄ , perovskite-type Li _0.5 La _0.5 TiO ₃ , LIPON (Li _{3 + y} PO _4−x N _x ), Thio-LISICON (Li _3.25 Ge _0.25 P _0.75 S ₄ ) and the like, and amorphous inorganic lithium ion conductors include glass Li—Si—S—O, Li—PS, etc. Among them, from the viewpoint of conductivity, an amorphous inorganic lithium ion conductor is preferable, and a sulfide containing Li, P and S is more preferable, and a sulfide containing Li, P and S is a lithium ion. Because of its high conductivity, the use of sulfides containing Li, P and S as the inorganic solid electrolyte can lower the internal resistance of the battery and improve the output characteristics. Can be made.

Further, the sulfide containing Li, P and S is a sulfide glass composed of Li ₂ S and P ₂ S ₅ and / or Li ₂ S and P ₂ from the viewpoint of lowering the internal resistance of the battery and improving the output characteristics. more preferably a sulfide glass ceramics obtained by mixing raw material is subjected to a mechanochemical method with S _5, Li ₂ S: molar ratio 65 of _{P 2 S 5: 35 ~ 85} : 15 of Li ₂ S and P It is particularly preferable to be a sulfide glass produced from a mixed raw material with ₂ S ₅ and / or a sulfide glass ceramic obtained by subjecting the mixed raw material to a mechanochemical method.

When an inorganic solid electrolyte is produced with a mixed raw material of Li ₂ S and P ₂ S _{5 of} Li ₂ S: P ₂ S ₅ = 65: 35 to 85:15 (molar ratio), the lithium ion conductivity is high. Can be maintained in a state. From the same viewpoint, it is more preferable that Li ₂ S: P ₂ S ₅ = 68: 32 to 80:20.
Specifically, the lithium ion conductivity is preferably 1 × 10 ⁻⁴ S / cm or more, and more preferably 1 × 10 ⁻³ S / cm or more.

The inorganic solid electrolyte used in the present invention is not limited to sulfide glass composed only of Li, P, and S, and sulfide glass ceramic composed only of Li, P, and S. As described later, other than Li, P, and S It may contain things.

The average particle size of the inorganic solid electrolyte is preferably in the range of 0.1 to 50 μm. By making the average particle diameter of the inorganic solid electrolyte within the above range, the solid electrolyte can be easily handled and the dispersibility of the inorganic solid electrolyte in the slurry composition when it is made into a sheet can be improved. Easy to form. From the above viewpoint, the average particle size of the inorganic solid electrolyte is more preferably in the range of 0.1 to 20 μm. The average particle size can be determined by measuring the particle size distribution by laser diffraction.

In the inorganic solid electrolyte used in the present invention, as a starting material in addition to the above P ₂ S ₅ and Li ₂ S, the inorganic solid electrolyte is selected from the group consisting of Al ₂ S ₃ , B ₂ S ₃ and SiS _2. It is preferable to include at least one selected sulfide. When such a sulfide is added, the glass component in the inorganic solid electrolyte can be stabilized.
Similarly, at least one orthooxo acid selected from the group consisting of Li ₃ PO ₄ , Li ₄ SiO ₄ , Li ₄ GeO ₄ , Li ₃ BO ₃ and Li ₃ AlO ₃ in addition to Li ₂ S and P ₂ S _5. It is preferable to include lithium. When such a lithium orthooxo acid is contained, the glass component in the inorganic solid electrolyte can be stabilized.

Solid Electrolyte Layer The solid electrolyte layer in the present invention contains the above-mentioned inorganic solid electrolyte and a polymer that serves as a binder. The solid electrolyte layer is formed by applying and drying a slurry composition for a solid electrolyte layer containing these inorganic solid electrolyte and a polymer as a binder on a positive electrode active material layer or a negative electrode active material layer described later. The

The slurry composition for a solid electrolyte layer is produced by mixing an inorganic solid electrolyte, a polymer serving as a binder, an organic solvent, and other components added as necessary. Even when the combination of the inorganic solid electrolyte and the alicyclic structure-containing polymer is contained only in a layer other than the solid electrolyte layer, the solid electrolyte layer necessarily contains the inorganic solid electrolyte. That is, in that case, the solid electrolyte layer is formed using, for example, an inorganic solid electrolyte and another polymer that may be used for the solid electrolyte layer as described later.

(Polymer used as binder)
As the polymer to be a binder, the above-described alicyclic structure-containing polymer may be used, and other polymers may be used, but in the all solid secondary battery of the present invention, the solid electrolyte layer, In at least one layer of the positive electrode active material layer and the negative electrode active material layer, preferably in all layers, an alicyclic structure-containing polymer is used as a polymer that serves as a binder.

Examples of other polymers that may be used for the solid electrolyte layer include polymer compounds such as fluorine polymers, diene polymers, acrylic polymers, silicone polymers, and the like. A diene polymer or an acrylic polymer is preferable, and an acrylic polymer is more preferable in that the withstand voltage can be increased and the energy density of the all-solid secondary battery can be increased.

Examples of the fluoropolymer include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP).

The diene polymer is a polymer including a monomer unit derived from a conjugated diene and a monomer unit derived from an aromatic vinyl. As the conjugated diene and the aromatic vinyl, other polymers in the negative electrode active material layer described later are used. The thing similar to what was illustrated in (1) is mentioned.

The acrylic polymer is a polymer containing a monomer unit derived from an α, β-ethylenically unsaturated monocarboxylic acid alkyl ester. Specifically, the acrylic polymer is an α, β-ethylenically unsaturated monocarboxylic acid alkyl ester. Homopolymer, copolymer of α, β-ethylenically unsaturated monocarboxylic acid alkyl ester, and α, β-ethylenically unsaturated monocarboxylic acid alkyl ester and said α, β-ethylenically unsaturated monocarboxylic acid alkyl Examples thereof include copolymers with other monomers copolymerizable with esters.
Examples of α, β-ethylenically unsaturated monocarboxylic acid alkyl esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, and t-butyl acrylate, acrylic acid- Acrylic acid alkyl esters such as 2-ethylhexyl, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, and benzyl acrylate; 2- (perfluorobutyl) ethyl acrylate, 2- (perfluoropentyl) ethyl acrylate 2- (perfluoroalkyl) ethyl acrylate such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, and t-butyl methacrylate, 2-ethylhexyl methacrylate , Methacrylic acid alkyl esters such as lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate and benzyl methacrylate; 2- (perfluorobutyl) ethyl methacrylate, 2- (perfluoropentyl) ethyl methacrylate Fluoroalkyl) ethyl;

The content ratio of the monomer unit derived from the α, β-ethylenically unsaturated monocarboxylic acid alkyl ester in the acrylic polymer is usually 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more. . The upper limit of the content ratio of the monomer units derived from the α, β-ethylenically unsaturated monocarboxylic acid alkyl ester in the acrylic polymer is usually 100% by weight or less, preferably 95% by weight or less.

The acrylic polymer includes a copolymer of α, β-ethylenically unsaturated monocarboxylic acid alkyl ester and another monomer copolymerizable with the α, β-ethylenically unsaturated monocarboxylic acid alkyl ester. Polymers are preferred. Examples of the copolymerizable monomer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, and fumaric acid; two or more carbons such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and trimethylolpropane triacrylate. Carboxylates having carbon double bonds; styrene, chlorostyrene, vinyl toluene, t-butyl styrene, vinyl benzoic acid, methyl vinyl benzoate, vinyl naphthalene, chloromethyl styrene, hydroxymethyl styrene, α-methyl styrene, Styrene monomers such as divinylbenzene; Amide monomers such as acrylamide, methacrylamide, N-methylolacrylamide, and acrylamide-2-methylpropanesulfonic acid; Olefins such as ethylene and propylene Diene monomers such as butadiene and isoprene; monomers containing halogen atoms such as vinyl chloride and vinylidene chloride; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate and vinyl benzoate; methyl vinyl ether, ethyl Vinyl ethers such as vinyl ether and butyl vinyl ether; Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone and isopropenyl vinyl ketone; 含有 N-vinyl pyrrolidone, vinyl pyridine, vinyl imidazole and other heterocyclic rings A vinyl compound is mentioned. Of these, styrene monomers and amide monomers are preferred from the viewpoint of solubility in organic solvents. The content of the copolymerizable monomer unit in the acrylic polymer is usually 60% by weight or less, preferably 55% by weight or less, more preferably 25% by weight or more and 45% by weight or less.

Examples of silicone polymers include silicone rubber, fluorosilicone rubber, and polyimide silicone.

Further, the polymer serving as the binder of the solid electrolyte layer may be a mixture of an alicyclic structure-containing polymer and other polymers. In that case, the content of the other polymer in the polymer to be the binder is usually 50% by weight or less, preferably 40% by weight or less.

The content of the polymer serving as the binder in the slurry composition for the solid electrolyte layer is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 7 parts by weight with respect to 100 parts by weight of the inorganic solid electrolyte. Particularly preferred is 0.5 to 5 parts by weight. By keeping the content of the polymer in the above range, it is possible to inhibit the movement of lithium and increase the resistance of the solid electrolyte layer while maintaining the binding property between the inorganic solid electrolyte particles.

(Lithium salt)
The solid electrolyte layer may include a lithium salt. Lithium salts are composed of Li ⁺ cations and anions such as Cl ⁻ , Br ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , ClO ₄ ⁻ , CF ₃ SO ₃ ⁻ , SCN ^{− and the} like, for example, lithium perchlorate Examples include lithium tetrafluoroborate, lithium hexafluorophosphate, lithium trifluoroacetate, lithium trifluoromethanesulfonate, and the like. The weight ratio of the binder polymer to the lithium salt is preferably 0.5 to 30 parts by weight, more preferably 3 to 25 parts by weight with respect to 100 parts by weight of the polymer. By setting the weight ratio of the polymer serving as the binder and the lithium salt within the above range, the ionic conductivity can be improved. The method for containing the lithium salt in the solid electrolyte layer is not particularly limited, and examples thereof include a method in which the polymer and the lithium salt are dissolved or dispersed in a solvent such as xylene to obtain a uniform solution.

(Organic solvent)
Examples of the organic solvent include cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene and xylene. These solvents can be used alone or in admixture of two or more, and can be appropriately selected and used from the viewpoints of drying speed and environment. In particular, in the present invention, they are aromatic because they are non-reactive with inorganic solid electrolytes. It is preferable to use a nonpolar solvent selected from group hydrocarbons.

The content of the organic solvent in the slurry composition for the solid electrolyte layer is preferably 10 to 700 parts by weight, more preferably 30 to 500 parts by weight with respect to 100 parts by weight of the inorganic solid electrolyte. By setting the content of the organic solvent in the above range, good coating properties can be obtained while maintaining the dispersibility of the inorganic solid electrolyte in the solid electrolyte layer slurry composition.

The slurry composition for a solid electrolyte layer may contain, in addition to the above components, components having functions of a dispersant, a leveling agent, and an antifoaming agent as other components added as necessary. These components are not particularly limited as long as they do not affect the battery reaction.

(Dispersant)
Examples of the dispersant include an anionic compound, a cationic compound, a nonionic compound, and a polymer compound. A dispersing agent is selected according to the inorganic solid electrolyte to be used. The content of the dispersant in the slurry composition for the solid electrolyte layer is preferably within a range that does not affect the battery characteristics, and specifically 10 parts by weight or less with respect to 100 parts by weight of the inorganic solid electrolyte.

(Leveling agent)
Examples of the leveling agent include surfactants such as alkyl surfactants, silicone surfactants, fluorine surfactants, and metal surfactants. By mixing the surfactant, it is possible to prevent the repelling that occurs when the slurry composition for the solid electrolyte layer is applied to the surface of the positive electrode active material layer or the negative electrode active material layer, which will be described later. Can be improved. The content of the leveling agent in the slurry composition for the solid electrolyte layer is preferably within a range that does not affect the battery characteristics. Specifically, it is 10 parts by weight or less with respect to 100 parts by weight of the inorganic solid electrolyte.

(Defoamer)
Examples of the antifoaming agent include mineral oil antifoaming agents, silicone antifoaming agents, and polymer antifoaming agents. The antifoaming agent is selected according to the inorganic solid electrolyte used. The content of the antifoaming agent in the solid electrolyte layer slurry composition is preferably within a range that does not affect the battery characteristics, and specifically, 10 parts by weight or less with respect to 100 parts by weight of the inorganic solid electrolyte.

Positive electrode active material layer The positive electrode active material layer is preferably formed using the above-described inorganic solid electrolyte and the above-described polymer that serves as the binder. Such a positive electrode active material layer is formed by applying a slurry composition for a positive electrode active material layer containing the inorganic solid electrolyte and the polymer serving as the binder to the surface of the current collector, which will be described later, and drying. The slurry composition for a positive electrode active material layer is produced by mixing an inorganic solid electrolyte, a polymer serving as a binder, a positive electrode active material, an organic solvent, and other components added as necessary.
The positive electrode active material layer does not necessarily contain an inorganic solid electrolyte. In that case, the positive electrode active material is mixed by mixing a polymer serving as a binder, a positive electrode active material, an organic solvent, and other components added as necessary. What is necessary is just to form the slurry composition for substance layers, and to form using the said composition.

Examples of the polymer (other polymer) other than the alicyclic structure-containing polymer that may be used for the positive electrode active material layer include, for example, a fluorine polymer, a diene polymer, an acrylic polymer, and a silicone polymer. High molecular compounds such as fluorine polymer, diene polymer or acrylic polymer are preferable, and acrylic polymer can increase the withstand voltage and increase the energy density of the all-solid-state secondary battery. It is more preferable at the point which can do.

The acrylic polymer is a polymer containing monomer units derived from an α, β-ethylenically unsaturated monocarboxylic acid alkyl ester. Examples of the α, β-ethylenically unsaturated monocarboxylic acid alkyl ester include those exemplified for the other polymers in the above-mentioned solid electrolyte layer. In addition, the content of the monomer unit derived from the α, β-ethylenically unsaturated monocarboxylic acid alkyl ester in the acrylic polymer suitable as the other polymer is preferably 60 to 100% by weight, more preferably 65 to 90% by weight.

The acrylic polymer includes a copolymer of an α, β-ethylenically unsaturated monocarboxylic acid alkyl ester and a monomer copolymerizable with the α, β-ethylenically unsaturated monocarboxylic acid alkyl ester. Coalescence is preferred. The copolymerizable monomer is the same as that exemplified in the other polymer in the solid electrolyte layer.

Further, the polymer serving as the binder for the positive electrode active material layer may be a mixture of an alicyclic structure-containing polymer and other polymers. In that case, the content of the other polymer in the polymer serving as the binder is the same as in the case of the solid electrolyte layer.

(Positive electrode active material)
The positive electrode active material is a compound that can occlude and release lithium ions. The positive electrode active material is roughly classified into those made of inorganic compounds and those made of organic compounds.

Examples of the positive electrode active material made of an inorganic compound include transition metal oxides, composite oxides of lithium and transition metals, and transition metal sulfides. As the transition metal, Fe, Co, Ni, Mn and the like are used. Specific examples of the inorganic compound used for the positive electrode active material include LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiFePO ₄ , LiFeVO _4, and other lithium-containing composite metal oxides; TiS ₂ , TiS ₃ , non- Transition metal sulfides such as crystalline MoS ₂ ; transition metal oxides such as Cu ₂ V ₂ O ₃ , amorphous V ₂ O—P ₂ O ₅ , MoO ₃ , V ₂ O ₅ , V ₆ O ₁₃ It is done. These compounds may be partially element-substituted.

Examples of the positive electrode active material made of an organic compound include polyaniline, polypyrrole, polyacene, disulfide compounds, polysulfide compounds, and N-fluoropyridinium salts.
The positive electrode active material may be a mixture of the above inorganic compound and organic compound.

The average particle size of the positive electrode active material used in the present invention is usually 0.1 to 50 μm, preferably 1 to 20 μm, from the viewpoint of improving battery characteristics such as load characteristics and cycle characteristics. When the average particle size is in the above range, an all-solid secondary battery having a large charge / discharge capacity can be obtained, and handling of the slurry composition for the positive electrode active material layer and handling of the positive electrode are easy. . The average particle size can be determined by measuring the particle size distribution by laser diffraction.

The weight ratio of the positive electrode active material to the inorganic solid electrolyte is usually positive electrode active material: inorganic solid electrolyte = 90: 10 to 30:70, preferably 80:20 to 40:60. When the weight ratio of the positive electrode active material is smaller than the above range, the amount of the positive electrode active material in the battery tends to be reduced, leading to a decrease in capacity as a battery. In addition, when the weight ratio of the inorganic solid electrolyte is less than the above range, sufficient conductivity cannot be obtained, and the positive electrode active material cannot be used effectively, so that the battery capacity tends to be reduced.

The content of the polymer serving as the binder in the positive electrode active material layer slurry composition is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 7 parts by weight with respect to 100 parts by weight of the positive electrode active material. It is. When the content of the polymer is in the above range, it is possible to prevent the positive electrode active material from dropping from the electrode without inhibiting the battery reaction.

The organic solvent in the positive electrode active material layer slurry composition and other components added as necessary may be the same as those exemplified for the solid electrolyte layer. The content of the organic solvent in the positive electrode active material layer slurry composition is preferably 20 to 300 parts by weight, more preferably 30 to 200 parts by weight with respect to 100 parts by weight of the positive electrode active material. When the content of the organic solvent in the positive electrode active material layer slurry composition is in the above range, good coating properties can be obtained while maintaining the dispersibility of the inorganic solid electrolyte.

In addition to the above components, the positive electrode active material layer slurry composition includes the above-described lithium salt, dispersant, leveling agent, antifoaming agent, conductive agent, reinforcing material as other components added as necessary. An additive that exhibits various functions such as these may be included. These are not particularly limited as long as they do not affect the battery reaction.

(Conductive agent)
The conductive agent is not particularly limited as long as it can impart conductivity, and usually includes carbon powders such as acetylene black, carbon black and graphite, and fibers and foils of various metals.

The amount of the conductive agent added is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 5 parts by weight, and particularly preferably 1 to 3 parts by weight with respect to 100 parts by weight of the positive electrode active material. By setting the content of the conductive agent in the above range, it is possible to impart sufficient electron conductivity to the electrode active material layer while keeping the battery capacity high.

(Reinforcing material)
As the reinforcing material, various inorganic and organic spherical, plate-like, rod-like or fibrous fillers can be used.

The addition amount of the reinforcing material is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 5 parts by weight, and particularly preferably 1 to 3 parts by weight with respect to 100 parts by weight of the positive electrode active material. By setting the content of the reinforcing material in the above range, it is possible to impart sufficient strength to the electrode active material layer while keeping the battery capacity high.

Negative electrode active material layer The negative electrode active material layer is preferably formed using the above-mentioned inorganic solid electrolyte and the above polymer serving as the binder. Such a negative electrode active material layer is formed by applying a slurry composition for a negative electrode active material layer containing the inorganic solid electrolyte and the polymer that serves as the binder to the surface of the current collector, which will be described later, and drying. The slurry composition for a negative electrode active material layer is produced by mixing an inorganic solid electrolyte, a polymer serving as a binder, a negative electrode active material, an organic solvent, and other components added as necessary.
Note that the negative electrode active material layer does not necessarily include an inorganic solid electrolyte. In that case, a negative electrode active material is mixed by mixing a polymer serving as a binder, a negative electrode active material, an organic solvent, and other components added as necessary. What is necessary is just to form the slurry composition for substance layers, and to form using the said composition.

Examples of other polymers that may be used in the negative electrode active material layer include polymer compounds such as fluorine-based polymers, diene-based polymers, acrylic polymers, and silicone-based polymers. Among them, a diene polymer containing a monomer unit derived from a conjugated diene and a monomer unit derived from an aromatic vinyl can bind negative electrode active materials to each other, and has a high binding force between the active material layer and the current collector. More preferred. Moreover, the polymer used as the binder of the negative electrode active material layer may be a mixture of an alicyclic structure-containing polymer and other polymers. In that case, the content of the other polymer in the polymer serving as the binder is the same as in the case of the solid electrolyte layer.

The content ratio of the monomer unit derived from the conjugated diene in the diene polymer is preferably 30 to 70% by weight, more preferably 35 to 65% by weight, and the content ratio of the monomer unit derived from the aromatic vinyl is preferably Is 30 to 70% by weight, more preferably 35 to 65% by weight. By setting the content ratio of the monomer units derived from the conjugated diene contained in the diene polymer and the content ratio of the monomer units derived from the aromatic vinyl within the above ranges, the negative electrode active materials, the inorganic solid electrolyte particles, A negative electrode having a high binding property between the particles of the substance and the inorganic solid electrolyte particles and between the active material layer and the current collector can be obtained.

Examples of the conjugated diene include butadiene, isoprene, 2-chloro-1,3-butadiene, chloroprene and the like. Of these, butadiene is preferred.

Examples of the aromatic vinyl include styrene, chlorostyrene, vinyl toluene, t-butyl styrene, vinyl benzoic acid, methyl vinyl benzoate, vinyl naphthalene, chloromethyl styrene, hydroxymethyl styrene, α-methyl styrene, divinyl benzene, and the like. . Of these, styrene, α-methylstyrene, and divinylbenzene are preferable.

Further, the diene polymer may be a copolymer of a conjugated diene, an aromatic vinyl, and a monomer copolymerizable therewith. Examples of the copolymerizable monomer include α, β-unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, and fumaric acid; ethylene, propylene, and the like Olefins; Halogen-containing monomers such as vinyl chloride and vinylidene chloride; Vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate and vinyl benzoate; Vinyl ethers such as methyl vinyl ether, ethyl vinyl ether and butyl vinyl ether; Methyl vinyl Examples thereof include vinyl ketones such as ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone, and isopropenyl vinyl ketone; and heterocyclic ring-containing vinyl compounds such as N-vinyl pyrrolidone, vinyl pyridine, and vinyl imidazole. The content of the copolymerizable monomer unit in the diene polymer is preferably 40% by weight or less, more preferably 20% by weight or more and 40% by weight or less.

(Negative electrode active material)
Examples of the negative electrode active material include carbon allotropes such as graphite and coke. The negative electrode active material composed of the allotrope of carbon can also be used in the form of a mixture with a metal, a metal salt, an oxide, or the like or a cover. Further, as the negative electrode active material, oxides and sulfates such as silicon, tin, zinc, manganese, iron, and nickel, lithium alloys such as lithium metal, Li—Al, Li—Bi—Cd, and Li—Sn—Cd, Lithium transition metal nitride, silicone, etc. can be used.

The average particle size of the negative electrode active material used in the present invention is usually 1 to 50 μm, preferably 15 to 30 μm, from the viewpoint of improving battery characteristics such as load characteristics and cycle characteristics. When the average particle size is in the above range, an all-solid secondary battery having a large charge / discharge capacity can be obtained, and handling of the slurry composition for the negative electrode active material layer and handling of the negative electrode are easy. . The average particle size can be determined by measuring the particle size distribution by laser diffraction.

The weight ratio of the negative electrode active material to the inorganic solid electrolyte is usually negative electrode active material: inorganic solid electrolyte = 90: 10 to 30:70, preferably 80:20 to 40:60. When the weight ratio of the negative electrode active material is smaller than the above range, the amount of the negative electrode active material in the battery tends to be reduced, leading to a decrease in capacity as a battery. In addition, when the weight ratio of the inorganic solid electrolyte is less than the above range, sufficient conductivity cannot be obtained, and the negative electrode active material cannot be used effectively, so that the battery capacity tends to be reduced.

The content of the polymer serving as a binder in the slurry composition for the negative electrode active material layer is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 7 parts by weight with respect to 100 parts by weight of the negative electrode active material. It is. When the content of the polymer is in the above range, it is possible to prevent the negative electrode active material from dropping from the electrode without inhibiting the battery reaction.

The organic solvent in the negative electrode active material layer slurry composition and other components added as necessary can be the same as those exemplified for the solid electrolyte layer. The content of the organic solvent in the negative electrode active material layer slurry composition is preferably 20 to 300 parts by weight, more preferably 30 to 200 parts by weight with respect to 100 parts by weight of the negative electrode active material. When the content of the organic solvent in the slurry composition for the negative electrode active material layer is within the above range, good coating properties can be obtained while maintaining the dispersibility of the inorganic solid electrolyte.

In addition to the above components, the slurry composition for the negative electrode active material layer includes the above-described lithium salt, dispersant, leveling agent, antifoaming agent, conductive agent, reinforcing material, and the like as other components added as necessary. Additives that exhibit various functions may be included. These are not particularly limited as long as they do not affect the battery reaction.

(Current collector)
The current collector is not particularly limited as long as it is an electrically conductive and electrochemically durable material. From the viewpoint of having heat resistance, for example, iron, copper, aluminum, nickel, stainless steel, etc. Metal materials such as titanium, tantalum, gold, and platinum are preferable. Among these, aluminum is particularly preferable for the positive electrode, and copper is particularly preferable for the negative electrode. The shape of the current collector is not particularly limited, but a sheet shape having a thickness of about 0.001 to 0.5 mm is preferable. In order to increase the adhesive strength between the current collector and the positive and negative electrode active material layers described above, the current collector is preferably used after being subjected to a roughening treatment. Examples of the roughening method include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method. In the mechanical polishing method, an abrasive cloth paper with a fixed abrasive particle, a grindstone, an emery buff, a wire brush provided with a steel wire or the like is used. Further, an intermediate layer may be formed on the surface of the current collector in order to increase the adhesive strength and conductivity between the current collector and the positive / negative electrode active material layer.

(Production of slurry composition for solid electrolyte layer, slurry composition for positive electrode active material layer, and slurry composition for negative electrode active material layer)
Said slurry composition is obtained by mixing each component mentioned above. The mixing method of each component of the slurry composition is not particularly limited, and examples thereof include a method using a mixing apparatus such as a stirring type, a shaking type, and a rotary type. In addition, a method using a dispersion kneader such as a homogenizer, a ball mill, a bead mill, a planetary mixer, a sand mill, a roll mill, and a planetary kneader can be mentioned. From the viewpoint that aggregation of an inorganic solid electrolyte can be suppressed, Alternatively, a method using a bead mill is preferable.

The viscosity of the slurry composition for a solid electrolyte layer produced as described above is preferably 10 to 500 mPa · s, more preferably 15 to 400 mPa · s, and particularly preferably 20 to 300 mPa · s. When the viscosity of the slurry composition for the solid electrolyte layer is in the above range, the dispersibility and the coating property of the slurry composition are improved. When the viscosity of the slurry composition is less than 10 mPa · s, the slurry composition for the solid electrolyte layer may sag. Moreover, when the viscosity of the slurry composition exceeds 500 mPa · s, it may be difficult to reduce the thickness of the solid electrolyte layer.

The viscosity of the positive electrode active material layer slurry composition and the negative electrode active material layer slurry composition produced as described above is preferably 3000 to 50000 mPa · s, more preferably 4000 to 30000 mPa · s, and particularly preferably 5000 to 10,000 mPa · s. When the viscosity of the slurry composition for the positive electrode active material layer and the slurry composition for the negative electrode active material layer is in the above range, the dispersibility and the coatability of the slurry composition are improved. When the viscosity of the slurry composition is less than 3000 mPa · s, the active material and the inorganic solid electrolyte in the slurry composition may settle. Moreover, when the viscosity of this slurry composition exceeds 50000 mPa * s, the uniformity of a coating film may be lost.

In the present invention, the viscosity can be measured as a value at room temperature when the rotation speed of the spindle in the B-type viscometer is 60 rpm.

All-solid secondary battery The all-solid-state secondary battery of the present invention has a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, and a solid electrolyte layer between these positive and negative electrode active material layers, The alicyclic structure-containing polymer and the inorganic solid electrolyte are contained in at least one layer of the positive electrode active material layer, the negative electrode active material layer or the solid electrolyte layer, preferably in all layers. Improve the initial discharge capacity and high temperature retention characteristics of the battery by including the alicyclic structure-containing polymer and the inorganic solid electrolyte in at least one of the positive electrode active material layer, the negative electrode active material layer, or the solid electrolyte layer. Can do.

The thickness of the solid electrolyte layer in the all solid state secondary battery of the present invention is preferably 1 to 15 μm, more preferably 2 to 13 μm, and particularly preferably 3 to 10 μm. When the thickness of the solid electrolyte layer is in the above range, the internal resistance of the all-solid secondary battery can be reduced.

The positive electrode in the all-solid-state secondary battery of the present invention is manufactured by applying the positive electrode active material layer slurry composition onto a current collector and drying to form a positive electrode active material layer. In addition, the negative electrode in the all-solid-state secondary battery of the present invention is obtained by applying the above slurry composition for the negative electrode active material layer on a current collector different from the positive electrode current collector and drying the negative electrode active material layer. Formed and manufactured. Next, the solid electrolyte layer slurry composition is applied on the formed positive electrode active material layer or negative electrode active material layer and dried to form a solid electrolyte layer. In addition, a solid electrolyte layer can also be formed by apply | coating the slurry composition for solid electrolyte layers on a carrier film, drying, and transferring on a positive electrode active material layer or a negative electrode active material layer. And an all-solid-state secondary battery element is manufactured by bonding together the electrode which did not form a solid electrolyte layer, and the electrode which formed said solid electrolyte layer.

The method for applying the slurry composition for the positive electrode active material layer and the slurry composition for the negative electrode active material layer to the current collector is not particularly limited. For example, the doctor blade method, the dip method, the reverse roll method, the direct roll method, and the gravure method It is applied by the extrusion method, brush coating or the like. The amount to be applied is not particularly limited, but is such an amount that the thickness of the active material layer formed after removing the organic solvent is usually 5 to 300 μm, preferably 10 to 250 μm. The drying method is not particularly limited, and examples thereof include drying with warm air, hot air, low-humidity air, vacuum drying, and drying by irradiation with (far) infrared rays or electron beams. The drying conditions are usually adjusted so that the organic solvent volatilizes as quickly as possible within a speed range in which stress concentration occurs and the active material layer cracks or the active material layer does not peel from the current collector. Furthermore, you may stabilize an electrode by pressing the electrode after drying. Examples of the pressing method include, but are not limited to, a mold press and a calendar press.

Drying is performed at a temperature at which the organic solvent is sufficiently volatilized. Specifically, the drying temperature is preferably 50 to 250 ° C., more preferably 80 to 200 ° C. By setting it as the said range, it becomes possible to form a favorable active material layer without the thermal decomposition of the polymer used as a binder. The drying time is not particularly limited, but is usually in the range of 10 to 60 minutes.

A method for applying the slurry composition for the solid electrolyte layer to the positive electrode active material layer, the negative electrode active material layer or the carrier film is not particularly limited, and the above-described slurry composition for the positive electrode active material layer and the slurry composition for the negative electrode active material layer are described above. However, the gravure method is preferred from the viewpoint that a thin solid electrolyte layer can be formed. The amount to be applied is not particularly limited, but is an amount such that the thickness of the solid electrolyte layer formed after removing the organic solvent is preferably 1 to 15 μm, more preferably 3 to 14 μm. The drying method, drying conditions, and drying temperature are also the same as those of the above-described slurry composition for positive electrode active material layer and slurry composition for negative electrode active material layer.

Furthermore, a laminate in which the electrode on which the solid electrolyte layer is formed and the electrode on which the solid electrolyte layer is not formed may be pressed. The pressurizing method is not particularly limited, and examples thereof include a flat plate press, a roll press, and CIP (Cold Isostatic Press). The pressure for pressing is preferably 5 to 700 MPa, more preferably 7 to 500 MPa. This is because by setting the pressure of the pressure press within the above range, the resistance at each interface between the electrode and the solid electrolyte layer, and further, the contact resistance between particles in each layer is lowered, and good battery characteristics are exhibited.

There is no particular limitation on whether the positive electrode active material layer or the negative electrode active material layer is coated with the slurry composition for the solid electrolyte layer, but the solid electrolyte layer slurry is applied to the active material layer having the larger particle diameter of the electrode active material to be used. It is preferable to apply the composition. When the particle diameter of the electrode active material is large, unevenness is formed on the surface of the active material layer. Therefore, the unevenness on the surface of the active material layer can be reduced by applying the composition. Therefore, when the electrode formed with the solid electrolyte layer and the electrode not formed with the solid electrolyte layer are bonded and laminated, the contact area between the solid electrolyte layer and the electrode is increased, and the interface resistance can be suppressed. .

The obtained all-solid-state secondary battery element is put into a battery container as it is or wound or folded according to the shape of the battery, and sealed to obtain an all-solid-state secondary battery. If necessary, an expanded metal, an overcurrent prevention element such as a fuse or a PTC element, a lead plate or the like can be placed in the battery container to prevent an increase in pressure inside the battery and overcharge / discharge. The shape of the battery may be any of a coin shape, a button shape, a sheet shape, a cylindrical shape, a square shape, a flat shape, and the like.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples. Each characteristic is evaluated by the following method. Note that “part” and “%” in this example are “part by weight” and “% by weight”, respectively, unless otherwise specified.

<Particle size distribution (average particle size)>
The dispersion particle diameter of the inorganic solid electrolyte in the slurry composition for the solid electrolyte layer was measured using a laser diffraction particle size distribution measuring device to determine the volume average particle diameter D50, and the dispersibility was evaluated according to the following criteria. The smaller the volume average particle diameter D50, the lower the degree of aggregation and the better the dispersibility.
A: Less than 10 μm B: 10 μm or more but less than 20 μm C: 20 μm or more but less than 30 μm D: 30 μm or more but less than 50 μm E: 50 μm or more

<Battery characteristics: initial discharge capacity>
A 10-cell all-solid-state secondary battery was charged to 4.3 V by a constant current method of 0.1 C at 25 ° C., and then discharged to 3.0 V at 0.1 C to obtain a 0.1 C discharge capacity x. . The discharge capacity ratio (x / X (%)) was obtained with respect to the theoretical capacity X of the active material, and the average value was evaluated according to the following criteria. It shows that it is excellent in initial stage discharge capacity, so that discharge capacity ratio (x / X) is high.
A: 90% or more B: 80% or more and less than 90% C: 70% or more and less than 80% D: 60% or more and less than 70% E: Less than 60%

<Battery characteristics: High temperature retention characteristics>
A 10-cell all-solid-state secondary battery was charged to 4.3 V by a constant current method of 0.1 C at 25 ° C., and then discharged to 3.0 V at 0.1 C to obtain a 0.1 C discharge capacity x. . Thereafter, the battery was charged to 4.3 V at 0.1 C, then left standing in an 80 ° C. constant temperature bath for 7 days, and then discharged to 3.0 V at 0.1 C to determine the discharge capacity y. Using the average value of 10 cells as a measured value, the capacity retention represented by the ratio (y / x (%)) of the electric capacity between the discharge capacity y after standing and the 0.1 C discharge capacity x is obtained, and the high temperature retention characteristics Was evaluated according to the following criteria. Higher values indicate better output characteristics, that is, lower internal resistance.
A: 90% or more B: 80% or more and less than 90% C: 70% or more and less than 80% D: 60% or more and less than 70% E: Less than 60%

<Hydrogenation rate>
The hydrogenation rate is obtained by measuring the ¹ H-NMR spectrum before and after the hydrogenation reaction, and calculating the integral value of the signals corresponding to the unsaturated bond of the main chain and the side chain part and the unsaturated bond of the aromatic ring before and after the hydrogenation reaction. Calculated based on the amount of decrease.

Example 1
[Production of alicyclic structure-containing polymer (block copolymer hydride (I))]
Into a reactor equipped with a stirrer sufficiently purged with nitrogen, 550 parts of dehydrated cyclohexane, 25.0 parts of dehydrated styrene and 0.475 part of n-dibutyl ether were added and stirred at 60 ° C. with n-butyllithium (15 % Cyclohexane solution) 0.515 parts was added to initiate polymerization. The mixture was reacted at 60 ° C. for 60 minutes with stirring. At this point in time as measured by gas chromatography, the polymerization conversion was 99.5%.
Next, 50.0 parts of dehydrated isoprene was added and stirring was continued for 30 minutes. At this time, the polymerization conversion rate was 99%.
Thereafter, 25.0 parts of dehydrated styrene was further added and stirred for 60 minutes. The polymerization conversion rate at this point was almost 100%. Here, 0.5 part of isopropyl alcohol was added to stop the reaction to obtain a block copolymer (i). The obtained block copolymer (i) had a weight average molecular weight (Mw) of 81,400 and a molecular weight distribution (Mw / Mn) of 1.05.

Next, the block copolymer (i) was transferred to a pressure-resistant reactor equipped with a stirrer, and a silica-alumina supported nickel catalyst (manufactured by JGC Chemical Industries, Ltd .; E22U, nickel supported amount 60%) as a hydrogenation catalyst. ) 4.0 parts and 100 parts dehydrated cyclohexane were added and mixed. The inside of the reactor was replaced with hydrogen gas, and hydrogen was supplied while stirring the solution. A hydrogenation reaction was performed at a temperature of 170 ° C. and a pressure of 4.5 MPa for 6 hours. The weight average molecular weight (Mw) of the block copolymer hydride (I) after the hydrogenation reaction was 86,200, and the molecular weight distribution (Mw / Mn) was 1.06.

After completion of the hydrogenation reaction, the reaction solution is filtered to remove the hydrogenation catalyst, and then phosphorous antioxidant 6- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propoxy] -2,4,8,10-tetrakis-t-butyldibenzo [d, f] [1.3.2] dioxaphosphine (Sumilyzer (registered trademark) GP, manufactured by Sumitomo Chemical Co., Ltd.) 0.1 part 1.0 part of the dissolved xylene solution was added and dissolved.
Next, the solution is filtered through a Zeta Plus filter 30H (Cuneau, pore size 0.5-1 μm), and further filtered through another metal fiber filter (pore size 0.4 μm, manufactured by Nichidai). After removing minute solids, cyclohexane, xylene and other volatilizations from the solution at a temperature of 260 ° C. and a pressure of 0.001 MPa or less using a cylindrical type concentrating dryer (manufactured by Hitachi, Ltd.) The components were removed, extruded from a die directly connected to a concentration dryer in the form of a strand in a molten state, cooled, and then cut with a pelletizer to obtain 85 parts of a block copolymer hydride (I) pellet. The resulting block copolymer hydride (I) had a weight average molecular weight (Mw) of 85,300 and a molecular weight distribution (Mw / Mn) of 1.11. The hydrogenation rate was almost 100%. Moreover, the weight fraction of the polymer block (A) and the polymer block (B) in the block copolymer hydride (I) was wA: wB = 50: 50.

[Production of slurry composition for positive electrode active material layer]
Sulfide glass (Li ₂ S / P ₂ S ₅ = 70 mol%) composed of 100 parts of lithium cobaltate (average particle size: 11.5 μm) as the positive electrode active material and Li ₂ S and P ₂ S ₅ as the inorganic solid electrolyte / 30 mol%, number average particle size: 0.4 μm) 150 parts, 13 parts of acetylene black as a conductive agent, and 3 parts of a cyclohexane solution of a block copolymer hydride (I) as a polymer as a binder (solid content) The mixture was further adjusted to a solid content concentration of 78% with cyclohexane as an organic solvent, and then mixed for 60 minutes with a planetary mixer. Furthermore, after adjusting to solid content concentration 74% with cyclohexane, it mixed for 10 minutes and prepared the slurry composition for positive electrode active material layers. The viscosity of the slurry composition for a positive electrode active material layer was 6100 mPa · s.

[Production of slurry composition for negative electrode active material layer]
Sulfide glass (Li ₂ S / P ₂ S ₅ = 70 mol% / 30 mol%) composed of 100 parts of graphite (average particle size: 20 μm) as the negative electrode active material and Li ₂ S and P ₂ S ₅ as the inorganic solid electrolyte (Number average particle size: 0.4 μm) 50 parts and 3 parts (corresponding to solid content) of a cyclohexane solution of a block copolymer hydride (I) as a polymer to be a binder are mixed, and further cyclohexane is used as an organic solvent. In addition, the solid content concentration was adjusted to 60%, and then mixed with a planetary mixer to prepare a slurry composition for a negative electrode active material layer. The viscosity of the negative electrode active material layer slurry composition was 6100 mPa · s.

[Production of slurry composition for solid electrolyte layer]
Sulfide glass composed of Li ₂ S and P ₂ S ₅ as an inorganic solid electrolyte (Li ₂ S / P ₂ S ₅ = 70 mol% / 30 mol%, number average particle diameter: 1.2 μm, cumulative 90% particle diameter: 2.1 μm) and 100 parts of a cyclohexane solution of block copolymer hydride (I) as a polymer to be a binder (corresponding to solid content) are mixed, and cyclohexane is added as an organic solvent to obtain a solid content concentration. After adjusting to 30%, it was mixed with a planetary mixer to prepare a slurry composition for a solid electrolyte layer. The viscosity of the solid electrolyte layer slurry composition was 52 mPa · s. The particle size distribution was evaluated using this slurry composition for a solid electrolyte layer. The results are shown in Table 1.

[Manufacture of all-solid-state secondary batteries]
The positive electrode active material layer slurry composition was applied to the surface of a current collector (aluminum, thickness 15 μm) and dried (110 ° C., 20 minutes) to form a 50 μm positive electrode active material layer to produce a positive electrode. The negative electrode active material layer slurry composition is applied to the surface of another current collector (copper, thickness 10 μm) and dried (110 ° C., 20 minutes) to form a 30 μm negative electrode active material layer. Manufactured.

Next, the solid electrolyte layer slurry composition was applied to the surface of the positive electrode active material layer and dried (110 ° C., 10 minutes) to form an 11 μm solid electrolyte layer.

The solid electrolyte layer laminated on the surface of the positive electrode active material layer and the negative electrode active material layer of the negative electrode were bonded together and pressed to obtain an all-solid secondary battery. The thickness of the solid electrolyte layer of the all-solid secondary battery after pressing was 9 μm. Using this battery, the initial discharge capacity and the high temperature retention characteristics were evaluated. The results are shown in Table 1.

(Example 2)
Each slurry composition was the same as in Example 1 except that the block copolymer hydride (I) was used in place of the block copolymer hydride (I) as the polymer to be a binder. An all-solid secondary battery was fabricated and evaluated. The results are shown in Table 1.

[Production of alicyclic structure-containing polymer (block copolymer hydride (II))]
In the polymerization stage, 15.0 parts of styrene, 0.310 parts of n-butyllithium (15% cyclohexane solution), 70.0 parts of isoprene, and 15.0 parts of styrene were added to the reaction system in this order and polymerized. 88 parts of pellets of block copolymer hydride (II) were obtained in the same manner as in Example 1 except that the process was started. The resulting block copolymer hydride (II) had a weight average molecular weight (Mw) of 139,000 and a molecular weight distribution (Mw / Mn) of 1.15. The hydrogenation rate was almost 100%. Moreover, the weight fraction of the polymer block (A) and the polymer block (B) in the block copolymer hydride (II) was wA: wB = 30: 70.

(Example 3)
Each slurry composition was the same as in Example 1 except that the block copolymer hydride (I) was used instead of the block copolymer hydride (I) as the binder polymer. An all-solid secondary battery was fabricated and evaluated. The results are shown in Table 1.

[Production of alicyclic structure-containing polymer (block copolymer hydride (III))]
In the same manner as in Example 1, except that 35.0 parts of styrene, 30.0 parts of isoprene, and 35.0 parts of styrene were added to the reaction system in this order and polymerization was started as monomers in the polymerization stage. 90 parts of pellets of copolymer hydride (III) were obtained. The resulting block copolymer hydride (III) had a weight average molecular weight (Mw) of 86,900 and a molecular weight distribution (Mw / Mn) of 1.10. The hydrogenation rate was almost 100%. Moreover, the weight fraction of the polymer block (A) and the polymer block (B) in the block copolymer hydride (III) was wA: wB = 70: 30.

(Example 4)
Each slurry composition was the same as in Example 1 except that the following random copolymer hydride (IV) was used as the binder polymer instead of the block copolymer hydride (I). An all-solid secondary battery was fabricated and evaluated. The results are shown in Table 1.

[Production of alicyclic structure-containing polymer (random copolymer hydride (IV))]
As a monomer in the polymerization stage, a mixed monomer of 50.0 parts of styrene and 50.0 parts of isoprene was added to the reaction system to start polymerization, and a random copolymer (iv) was obtained. Subsequently, the random copolymer (iv) was hydrogenated in the same manner as in Example 1 to obtain a random copolymer hydride (IV). The obtained random copolymer hydride (IV) had a weight average molecular weight (Mw) of 141,000 and a molecular weight distribution (Mw / Mn) of 1.15. The hydrogenation rate was almost 100%.

(Example 5)
Each slurry composition was the same as in Example 1 except that the block copolymer hydride (I) was used in place of the block copolymer hydride (I) as the binder polymer. An all-solid secondary battery was fabricated and evaluated. The results are shown in Table 1.

[Production of alicyclic structure-containing polymer (block copolymer hydride (V))]
Example 1 except that polymerization was started by adding 25.0 parts of styrene as a monomer in the polymerization stage, 50.0 parts of liquefied butadiene instead of isoprene, and 25.0 parts of styrene in this order to the reaction system. Similarly, 87 parts of a block copolymer hydride (V) pellet was obtained. The resulting block copolymer hydride (V) had a weight average molecular weight (Mw) of 139,000 and a molecular weight distribution (Mw / Mn) of 1.11. The hydrogenation rate was almost 100%. Moreover, the weight fraction of the polymer block (A) and the polymer block (B) in the block copolymer hydride (V) was wA: wB = 50: 50.

(Example 6)
In the production of the slurry composition for the negative electrode active material layer and the slurry composition for the solid electrolyte layer, as a polymer serving as a binder, a butyl acrylate-styrene copolymer (butyl acrylate / styrene copolymer ratio = 70/30, Each slurry composition and all-solid secondary battery were prepared and evaluated in the same manner as in Example 1 except that Tg-2 ° C. was used. The results are shown in Table 1.

(Example 7)
Each slurry composition, all solids was the same as in Example 1 except that the following norbornene-based polymer hydride was used in place of the block copolymer hydride (I) as the binder polymer. A secondary battery was produced and evaluated. The results are shown in Table 1.

[Production of polymer containing alicyclic structure (hydride of norbornene polymer)]
(Ring-opening polymerization)
Under a nitrogen atmosphere, 700 parts of dehydrated cyclohexane were mixed with 0.89 part of 1-hexene, 1.06 part of diisopropyl ether, 0.34 part of triisobutylaluminum, and 0.13 part of isobutyl alcohol at room temperature and mixed. . There, 250 parts of 2-norbornene (2-NB), 1.25 parts of 5-vinyl-2-norbornene (hereinafter sometimes referred to as “VNB”) and 26 parts of tungsten hexachloride 1.0% toluene solution. Was continuously added over 2 hours while maintaining the temperature at 55 ° C. to carry out polymerization to obtain a ring-opening polymer. The polymerization conversion rate was almost 100%. The blending amount of VNB as a branching agent was 0.39 mol% when the total amount of 2-NB as a norbornene monomer was 100 mol%.

(Hydrogenation reaction)
The reaction solution containing the ring-opening polymer obtained above was transferred to a pressure-resistant hydrogenation reactor, and 1.0 part of diatomaceous earth-supported nickel catalyst (T8400, nickel support rate 58%, manufactured by Zudhemy Catalyst Co., Ltd.) was added thereto. In addition, the reaction was performed at 200 ° C. and a hydrogen pressure of 4.5 MPa for 6 hours. This solution was filtered through a filter equipped with a stainless steel wire mesh using diatomaceous earth as a filter aid to remove the catalyst. The obtained reaction solution was poured into 3000 parts of isopropyl alcohol with stirring to precipitate a hydride, which was collected by filtration. Further, after washing with 500 parts of acetone, it was dried in a vacuum drier set at 0.13 × 10 ³ Pa or less and 100 ° C. for 48 hours, and a crystalline norbornene-based ring-opening polymer hydrogen as a norbornene-based polymer hydride. 190 parts of the compound were obtained. The obtained norbornene polymer hydride had a weight average molecular weight (Mw) of 115,000 and a molecular weight distribution (Mw / Mn) of 1.10. The hydrogenation rate was almost 100%.

(Comparative Example 1)
Septon (registered trademark) 8006 (Kuraray polystyrene-poly (ethylene / butylene) block-polystyrene, styrene content: 33%) was used as the binder polymer in place of the block copolymer hydride (I). Except for this, each slurry composition and all-solid-state secondary battery were prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

From Table 1, an all-solid-state secondary battery of Examples 1 to 7 having a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, and a solid electrolyte layer, the positive electrode active material layer, the negative electrode An all-solid secondary battery in which at least one of the active material layer or the solid electrolyte layer includes a polymer containing an alicyclic structure and an inorganic solid electrolyte may have excellent initial discharge capacity and high temperature retention characteristics. I understand. Moreover, it is excellent in the dispersibility of the solid electrolyte in the slurry composition for solid electrolyte layers.
On the other hand, the comparative example 1 which does not contain the polymer containing an alicyclic structure is inferior in the balance of each evaluation.

Claims (7)

1. An all-solid secondary battery comprising a positive electrode having a positive electrode active material layer, a negative electrode having a negative electrode active material layer, and a solid electrolyte layer,
   An all-solid secondary battery, wherein at least one of a positive electrode active material layer, a negative electrode active material layer, or a solid electrolyte layer contains a polymer containing an alicyclic structure and an inorganic solid electrolyte.
2. The all-solid-state secondary battery according to claim 1, wherein the alicyclic structure is a structure in which an aromatic ring is hydrogenated.
3. A vinyl fat obtained by hydrogenating a copolymer of a vinyl aromatic monomer and another monomer copolymerizable with the monomer, the polymer comprising the alicyclic structure. A cyclic hydrocarbon polymer comprising:
   The all-solid-state secondary battery according to claim 1 or 2, wherein 90% or more of all carbon-carbon unsaturated bonds in the copolymer are hydrogenated.
4. The polymer containing the alicyclic structure is composed of a polymer block (A) mainly composed of a vinyl aromatic monomer unit obtained by hydrogenating a carbon-carbon unsaturated bond of an aromatic ring, and a carbon- The hydrogenated block copolymer according to any one of claims 1 to 3, which is a hydrogenated block copolymer having a polymer block (B) mainly composed of a chain conjugated diene monomer unit obtained by hydrogenating a carbon unsaturated bond. Solid secondary battery.
5. When the weight fraction of the polymer block (A) in the entire hydrogenated block copolymer is wA, and the weight fraction of the polymer block (B) in the entire hydrogenated block copolymer is wB, wA The all-solid-state secondary battery according to claim 4, wherein the ratio of w to wB (wA: wB) is 20:80 to 60:40.
6. 6. The all-solid-state secondary battery according to claim 1, wherein the polymer having an alicyclic structure has a weight average molecular weight of 30,000 to 200,000.
7. The all-solid-state secondary battery according to any one of claims 1 to 6, wherein the inorganic solid electrolyte is a sulfide glass and / or sulfide glass ceramics comprising Li ₂ S and P ₂ S ₅ .