JP6262503B2 - All-solid secondary battery and method for producing all-solid secondary battery - Google Patents

All-solid secondary battery and method for producing all-solid secondary battery Download PDF

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JP6262503B2
JP6262503B2 JP2013244428A JP2013244428A JP6262503B2 JP 6262503 B2 JP6262503 B2 JP 6262503B2 JP 2013244428 A JP2013244428 A JP 2013244428A JP 2013244428 A JP2013244428 A JP 2013244428A JP 6262503 B2 JP6262503 B2 JP 6262503B2
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JP2015103451A (en
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聡 藤木
聡 藤木
相原 雄一
雄一 相原
元 土屋
元 土屋
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Samsung Electronics Co Ltd
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/056Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0561Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
    • H01M10/0562Solid materials
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/052Li-accumulators
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/058Construction or manufacture
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/62Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621Binders
    • H01M4/622Binders being polymers
    • H01M4/623Binders being polymers fluorinated polymers
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00Electrolytes
    • H01M2300/0017Non-aqueous electrolytes
    • H01M2300/0065Solid electrolytes
    • H01M2300/0068Solid electrolytes inorganic
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

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Description

本発明は、全固体二次電池に関する。特に硫化物固体電解質と非極性溶媒不溶性の結着剤とを併用する全固体二次電池に関する。   The present invention relates to an all solid state secondary battery. In particular, the present invention relates to an all-solid secondary battery using a sulfide solid electrolyte and a nonpolar solvent-insoluble binder in combination.

全固体二次電池は、負極層と固体電解質層と正極層とを積層させた積層構造を備える。各層に含まれる固体電解質としては、高イオン伝導性の硫化物が好ましく用いられる。また積層構造内の正極活物質、固体電解質、負極活物質等の各粒子を結着させる結着剤として、スチレンブタジエンゴム(SBR)やポリフッ化ビニリデン(PVdF)が用いられる。   The all-solid-state secondary battery has a laminated structure in which a negative electrode layer, a solid electrolyte layer, and a positive electrode layer are laminated. As the solid electrolyte contained in each layer, a highly ionic conductive sulfide is preferably used. Styrene butadiene rubber (SBR) or polyvinylidene fluoride (PVdF) is used as a binder for binding particles such as a positive electrode active material, a solid electrolyte, and a negative electrode active material in a laminated structure.

特許文献1および特許文献2は、結着剤としてSBRを用いる例である。特許文献1に開示される全固体リチウム二次電池においては、集電体となる金属層と各電極層との間にSBRを含有する樹脂層を設ける。しかしSBRは結着力が弱い。そのため金属層の樹脂層対向面を粗面化させて結着性を高め、層間剥離を防止する。特許文献2には、正極活物質と、固体電解質材料と、SBRと導電化剤とを含有する正極合剤層形成用スラリーが開示される。上記のスラリーは、粒子間の結着性が不十分である。特許文献1および特許文献2に示されるように、SBRを全固体二次電池の結着剤とする場合、積層構造内の結着性を向上させるための構成が必要になる場合がある。そのため装置の複雑化とコスト上昇を招く。   Patent Document 1 and Patent Document 2 are examples in which SBR is used as a binder. In the all solid lithium secondary battery disclosed in Patent Document 1, a resin layer containing SBR is provided between a metal layer serving as a current collector and each electrode layer. However, SBR has a weak binding force. Therefore, the resin layer facing surface of the metal layer is roughened to enhance the binding property and prevent delamination. Patent Document 2 discloses a positive electrode mixture layer forming slurry containing a positive electrode active material, a solid electrolyte material, SBR, and a conductive agent. The above slurry has insufficient binding between particles. As shown in Patent Document 1 and Patent Document 2, when SBR is used as a binder for an all-solid-state secondary battery, a configuration for improving the binding property in the laminated structure may be required. As a result, the apparatus becomes complicated and the cost increases.

PVdFは、結着力が高い一方で、非極性溶媒に不溶である。そのため、PVdF含有スラリーの溶媒としては、N−メチルピロリドン(NMP)等の極性溶媒が選択される。
しかし固体二次電池製造用の正極合剤や負極合剤等のスラリー調製において、極性溶媒中に硫化物固体電解質を添加すると、硫化物固体電解質由来のアルカリ成分と極性溶媒とが反応し、溶液がスラリー状態を維持できなくなる。そのような溶液はハンドリング性が悪く、全固体二次電池の生産効率を低下させる。
While PVdF has a high binding force, it is insoluble in nonpolar solvents. Therefore, a polar solvent such as N-methylpyrrolidone (NMP) is selected as the solvent for the PVdF-containing slurry.
However, in the preparation of a slurry such as a positive electrode mixture or a negative electrode mixture for the production of a solid secondary battery, when a sulfide solid electrolyte is added to a polar solvent, the alkaline component derived from the sulfide solid electrolyte reacts with the polar solvent to produce a solution. Cannot maintain the slurry state. Such a solution has poor handling properties and reduces the production efficiency of the all-solid-state secondary battery.

また硫化物固体電解質含有層の形成工程においては、基材に塗布された合剤を乾燥させて極性溶媒を除去する。しかし上記の合剤を用いて形成した電極層や固体電解質層においては、硫化物固体電解質を含有することで期待される高イオン伝導度が得られない。その一因として、乾燥時間中に合剤内に存在する極性溶媒と硫化物固体電解質との反応が進み、電極層等における硫化物固体電解質のリチウムイオン伝導度が低下していることが推察される。   In the step of forming the sulfide solid electrolyte-containing layer, the mixture applied to the substrate is dried to remove the polar solvent. However, in an electrode layer or a solid electrolyte layer formed using the above mixture, high ion conductivity expected by containing a sulfide solid electrolyte cannot be obtained. One reason for this is that the reaction between the polar solvent present in the mixture and the sulfide solid electrolyte progresses during the drying time, and the lithium ion conductivity of the sulfide solid electrolyte in the electrode layer and the like is presumed to decrease. The

そのため、硫化物固体電解質含有スラリーの溶媒としては非極性溶媒が好ましい。その場合、PVdFは非極性溶媒に溶解しないためスラリー中で均質に分散しにくい。そのため全固体二次電池の構造内で均質な結着性を発揮できず、層間剥離を招来する。特許文献3には、スチレン系熱可塑性エラストマーと酸変性PVdFとの二種類の結着剤を、NMPを溶媒とするスラリーを用いて形成させた接着層を、正極層と集電部材との間に介在させた固体二次電池が開示される。上記の固体二次電池においては接着層を形成するため、製造工程が増えコストが高くなる。   Therefore, a nonpolar solvent is preferred as the solvent for the sulfide solid electrolyte-containing slurry. In that case, PVdF does not dissolve in the nonpolar solvent, and therefore, it is difficult to uniformly disperse in the slurry. Therefore, uniform binding cannot be exhibited within the structure of the all-solid-state secondary battery, resulting in delamination. In Patent Document 3, an adhesive layer formed by using a slurry using NMP as a solvent and two kinds of binders of a styrene-based thermoplastic elastomer and an acid-modified PVdF is provided between a positive electrode layer and a current collecting member. Disclosed is a solid secondary battery interposed therebetween. In the solid secondary battery, since the adhesive layer is formed, the number of manufacturing steps is increased and the cost is increased.

したがって、全固体二次電池の各部材が強固に接合され製品寿命が長い全固体二次電池を、低コストで製造することが求められる。また、硫化物固体電解質を用いることで得られるイオン伝導度を、最大限に引き出すことが求められる。   Therefore, it is required to manufacture an all-solid-state secondary battery having a long product life with each member of the all-solid-state secondary battery being firmly joined at a low cost. In addition, it is required to maximize the ionic conductivity obtained by using the sulfide solid electrolyte.

特開2009-289534号公報JP 2009-289534 特開2010-262764号公報JP 2010-262764 特開2013-125507号公報JP 2013-125507 A

本発明は、正極層と負極層と固体電解質層とが強固に結着され、製品寿命が長い全固体二次電池を提供することを課題とする。特に固体電解質として硫化物を用いる全固体電池において、高結着性と高イオン伝導度を兼ね備えることを課題とする。   An object of the present invention is to provide an all-solid-state secondary battery in which a positive electrode layer, a negative electrode layer, and a solid electrolyte layer are firmly bound and a product life is long. In particular, in an all-solid battery using sulfide as a solid electrolyte, it is an object to have both high binding properties and high ionic conductivity.

本発明は、正極層と、負極層と、固体電解質層とのいずれか一つ以上に、非連続的に存在する非極性溶媒不溶性の第一結着剤と、連続的に存在する非極性溶媒可溶性の第二結着剤とを含み、第一結着剤と第二結着剤とのSP値が異なる全固体二次電池である。正極層と負極層と固体電解質層とに含まれる固体電解質は、硫化物固体電解質であることが好ましい。該全固体二次電池においては、第一結着剤のSP値が20〔MPa1/2〕以上30〔MPa1/2〕以下であることが好ましい。第二結着剤のSP値は、5〔MPa1/2〕以上20〔MPa1/2〕未満であることが好ましい。また第一結着剤の平均粒子径は、0.01〜10μmが好ましい。 The present invention provides a non-polar solvent-insoluble first binder that is discontinuously present in any one or more of a positive electrode layer, a negative electrode layer, and a solid electrolyte layer, and a non-polar solvent that is continuously present An all-solid-state secondary battery including a soluble second binder and having different SP values between the first binder and the second binder. The solid electrolyte contained in the positive electrode layer, the negative electrode layer, and the solid electrolyte layer is preferably a sulfide solid electrolyte. In the all solid state secondary battery, the SP value of the first binder is preferably 20 [MPa 1/2 ] or more and 30 [MPa 1/2 ] or less. The SP value of the second binder is preferably 5 [MPa 1/2 ] or more and less than 20 [MPa 1/2 ]. The average particle size of the first binder is preferably 0.01 to 10 μm.

本発明の第一結着剤は、下記式(1)で表される構成単位を有する化合物であることが好ましい。その場合、第一結着剤と第二結着剤とのSP値差の絶対値は、3以上である。
The first binder of the present invention is preferably a compound having a structural unit represented by the following formula (1). In that case, the absolute value of the SP value difference between the first binder and the second binder is 3 or more.

本発明の第一結着剤は、下記式(2)で表される構成単位を有する化合物であってもよい。その場合、第一結着剤と第二結着剤とのSP値差の絶対値は、1以上である。
The first binder of the present invention may be a compound having a structural unit represented by the following formula (2). In that case, the absolute value of the SP value difference between the first binder and the second binder is 1 or more.

本発明の第二結着剤は、炭化水素系高分子が好ましい。   The second binder of the present invention is preferably a hydrocarbon polymer.

本発明は、非極性溶媒に、正極活物質と固体電解質と非極性溶媒不溶性の第一結着剤と非極性溶媒可溶性の第二結着剤とを添加する正極合剤調製工程と、非極性溶媒に、負極活物質と固体電解質と非極性溶媒不溶性の第一結着剤と非極性溶媒可溶性の第二結着剤とを添加する負極合剤調製工程と、固体電解質と非極性溶媒不溶性の第一結着剤と非極性溶媒可溶性の第二結着剤とを混合する固体電解質層形成工程とのいずれか一つ以上の工程を含む全固体二次電池の製造方法を包含する。   The present invention provides a positive electrode mixture preparation step of adding a positive electrode active material, a solid electrolyte, a nonpolar solvent-insoluble first binder and a nonpolar solvent-soluble second binder to a nonpolar solvent, A negative electrode mixture preparation step of adding a negative electrode active material, a solid electrolyte, a non-polar solvent-insoluble first binder and a non-polar solvent-soluble second binder to the solvent; a solid electrolyte and a non-polar solvent-insoluble The manufacturing method of the all-solid-state secondary battery including any one or more process of the solid electrolyte layer formation process which mixes a 1st binder and a nonpolar solvent soluble 2nd binder is included.

本発明は、結着力が強い結着剤を用いて正極層と固体電解質層と負極層とが強固に結着され、電池構造内に含有される粒子が剥離しにくい。これにより層間剥離が抑制され製品寿命が長い全固体二次電池を提供することができる。特に、本発明は固体電解質として硫化物固体電解質を用いる場合にも適用できるため、高結着性と高イオン伝導度を兼ね備える点で有利である。   In the present invention, the positive electrode layer, the solid electrolyte layer, and the negative electrode layer are firmly bound using a binder having a strong binding force, and particles contained in the battery structure are difficult to peel off. Thereby, delamination can be suppressed and an all-solid secondary battery having a long product life can be provided. In particular, since the present invention can be applied to the case where a sulfide solid electrolyte is used as the solid electrolyte, it is advantageous in that it has high binding properties and high ionic conductivity.

本発明の全固体二次電池の例を示す概略図である。It is the schematic which shows the example of the all-solid-state secondary battery of this invention. 本発明の第一結着剤と第二結着剤とを含有する正極層の例を示す模式図である。It is a schematic diagram which shows the example of the positive electrode layer containing the 1st binder and 2nd binder of this invention.

[全固体二次電池]
本発明の全固体二次電池は、正極層と固体電解質層と負極層とを積層させた積層構造を備える。図1は、本発明の全固体二次電池の一例を示す概略図である。図1において、100は全固体二次電池、200は正極層、300は固体電解質層、400は負極層、501、502は集電体である。
[All-solid secondary battery]
The all solid state secondary battery of the present invention has a laminated structure in which a positive electrode layer, a solid electrolyte layer, and a negative electrode layer are laminated. FIG. 1 is a schematic view showing an example of the all solid state secondary battery of the present invention. In FIG. 1, 100 is an all solid state secondary battery, 200 is a positive electrode layer, 300 is a solid electrolyte layer, 400 is a negative electrode layer, and 501 and 502 are current collectors.

正極層200には、正極活物質、固体電解質等の粒子が含まれる。固体電解質層300には、固体電解質粒子が含まれる。負極層400には、負極活物質、固体電解質等の粒子が含まれる。固体電解質粒子が正極層200および負極層400にも混合されることにより、固体電解質粒子と、正極活物質粒子または負極活物質粒子との界面を大きく確保して、イオン伝導性を良好にする。   The positive electrode layer 200 includes particles such as a positive electrode active material and a solid electrolyte. The solid electrolyte layer 300 includes solid electrolyte particles. The negative electrode layer 400 includes particles such as a negative electrode active material and a solid electrolyte. By mixing the solid electrolyte particles also in the positive electrode layer 200 and the negative electrode layer 400, a large interface between the solid electrolyte particles and the positive electrode active material particles or the negative electrode active material particles is secured, and the ion conductivity is improved.

正極層200と固体電解質層300と負極層400とには、結着剤が含有される。本発明においては、上記の結着剤を第二結着剤とする。第二結着剤は、上記の各層に連続的に存在するため、各層に含有される活物質や固体電解質の各粒子のいずれにも接触し結着させる。そのため正極層200と固体電解質層300との界面や、負極層400と固体電解質層300との界面を強固に接合させることができる。   The positive electrode layer 200, the solid electrolyte layer 300, and the negative electrode layer 400 contain a binder. In the present invention, the above binder is used as the second binder. Since the second binder is continuously present in each of the above layers, it is brought into contact with and bound to any of the particles of the active material and the solid electrolyte contained in each layer. Therefore, the interface between the positive electrode layer 200 and the solid electrolyte layer 300 and the interface between the negative electrode layer 400 and the solid electrolyte layer 300 can be firmly bonded.

さらに本発明は、正極層200と固体電解質層300と負極層400とのいずれか一つ以上に第一結着剤を含有する。第一結着剤は、含有される層内で非連続的に存在する。第一結着剤は、第二結着剤より結着力が強い結着剤が選択される。全固体二次電池の製造時、上記の積層構造は加圧されることで一体化する。全固体二次電池の積層構造の第一結着剤と第二結着剤とを含有する層は、第二結着剤により加圧前から活物質粒子や固体電解質粒子等の粒子間結着が維持される。   Furthermore, the present invention contains the first binder in any one or more of the positive electrode layer 200, the solid electrolyte layer 300, and the negative electrode layer 400. The first binder is discontinuously present in the contained layer. As the first binder, a binder having a stronger binding force than the second binder is selected. When the all-solid-state secondary battery is manufactured, the above laminated structure is integrated by being pressurized. The layer containing the first binder and the second binder in the laminated structure of the all-solid-state secondary battery is bound between particles such as active material particles and solid electrolyte particles before being pressed by the second binder. Is maintained.

また上記の結着される粒子間には第一結着剤の微小な粒子が介在する。そのような第一結着剤の微小な粒子は、積層構造が加圧されると融解し、上記粒子間の介在領域で強い結着力を発揮する。これにより、活物質粒子や固体電解質を強固に結着させることができる。したがって第一結着剤は層内に非連続的に、言い換えれば均質に存在しないとしても、その結着力は全固体二次電池の積層構造の層間剥離防止に寄与する。これにより本発明は、充放電を繰り返しても層間剥離が少なく、製品寿命が長い。   In addition, fine particles of the first binder are present between the particles to be bound. Such fine particles of the first binder melt when the laminated structure is pressurized, and exhibit a strong binding force in the intervening region between the particles. Thereby, the active material particles and the solid electrolyte can be firmly bound. Therefore, even if the first binder does not exist discontinuously in the layer, in other words, it does not exist uniformly, the binding force contributes to prevention of delamination of the laminated structure of the all-solid-state secondary battery. Thereby, even if charging / discharging is repeated, the present invention has little delamination and a long product life.

本発明において第一結着剤と第二結着剤とを含有する層は、正極層と負極層と固体電解質層とのいずれか一つであっても上記の作用効果を得ることができる。接合されるそれぞれの層に上記の二種類の結着剤が含有される場合、その接合性をより高めることができる。全ての層に二種類の結着剤が含有される場合、最も強固に接合された積層構造を得ることができる。   In the present invention, even if the layer containing the first binder and the second binder is any one of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer, the above-described effects can be obtained. When the above-mentioned two kinds of binders are contained in each layer to be joined, the joining property can be further improved. When two types of binders are contained in all layers, the most strongly bonded laminated structure can be obtained.

[正極層]
本発明の、正極層に第一結着剤と第二結着剤とを含有する態様について説明する。図2は、本発明の正極層の例を示す模式図である。図2において、200は正極層、201は正極活物質、202は第一結着剤、203は第二結着剤、301は固体電解質である。図2に示される正極層200は、層内に第一結着剤202が非連続的に存在し、第二結着剤203が連続的に存在する。言い換えれば、正極層内には、正極活物質201や固体電解質301の周囲に、粒子状の第一結着剤202を島成分とし、第二結着剤203を海成分とする海島構造が形成される。なお正極層200には、不図示の導電助剤等も含まれる。
[Positive electrode layer]
An embodiment of the present invention in which the positive electrode layer contains the first binder and the second binder will be described. FIG. 2 is a schematic view showing an example of the positive electrode layer of the present invention. In FIG. 2, 200 is a positive electrode layer, 201 is a positive electrode active material, 202 is a first binder, 203 is a second binder, and 301 is a solid electrolyte. In the positive electrode layer 200 shown in FIG. 2, the first binder 202 is discontinuously present in the layer, and the second binder 203 is continuously present in the layer. In other words, in the positive electrode layer, a sea-island structure is formed around the positive electrode active material 201 and the solid electrolyte 301 with the particulate first binder 202 as an island component and the second binder 203 as a sea component. Is done. The positive electrode layer 200 also includes a conductive aid (not shown).

本発明に用いられる第一結着剤としては、後に説明する第二結着剤より結着性が強い結着剤が選択される。結着性の強さは、支持体に結着剤溶液を塗布し乾燥させて得た結着剤シートを支持体から剥離させるために必要な力を、市販の剥離試験機で測定して評価することができる。   As the first binder used in the present invention, a binder having a binding property stronger than that of a second binder described later is selected. The strength of the binding property is evaluated by measuring the force required to peel the binder sheet obtained by applying the binder solution to the support and drying it, using a commercially available peel tester. can do.

第一結着剤は、式(1)で表される構成単位を有する化合物であることが好ましい。上記の化合物の具体例としては、PVdFが挙げられる。第一結着剤は、式(2)で表される構成単位を有する化合物でもよい。具体例としては、ポリビニルアルコール(PVA)が挙げられる。その他、ポリアクリル酸エステルの共重合体、ビニリデンフロライド−ヘキサフルオロプロピレン共重合体(VDF−HFP)およびそれらのカルボン酸変性物、塩素化ポリエチレン、ポリメタクリル酸エステル、エチレン−ビニルアルコール共重合体、ポリイミド、ポリアミド、ポリアミドイミド等でもよい。   The first binder is preferably a compound having a structural unit represented by the formula (1). Specific examples of the above compound include PVdF. The first binder may be a compound having a structural unit represented by the formula (2). Specific examples include polyvinyl alcohol (PVA). Other polyacrylic acid ester copolymers, vinylidene fluoride-hexafluoropropylene copolymers (VDF-HFP) and their carboxylic acid modified products, chlorinated polyethylene, polymethacrylic acid esters, ethylene-vinyl alcohol copolymers , Polyimide, polyamide, polyamideimide and the like may be used.

上記の化合物の分子量は1×10〜1×10が好ましく、2×10〜8×10がより好ましい。分子量が1×10より小さい場合、結着力が不十分になるため好ましくない。分子量が1×10を超える場合、スラリーの粘度が高くなりすぎて塗布が困難になるため好ましくない。 The molecular weight of the above compound is preferably 1 × 10 5 to 1 × 10 7 and more preferably 2 × 10 5 to 8 × 10 6 . When the molecular weight is smaller than 1 × 10 5 , the binding force becomes insufficient, which is not preferable. When the molecular weight exceeds 1 × 10 7 , it is not preferable because the viscosity of the slurry becomes too high to make application difficult.

第一結着剤は、正極層形成時や全固体二次電池の積層構造を一体化させる際に正極層に加えられる圧力により、正極層内で十分に融解する。そのため正極活物質や固体電解質の粒子間で第一結着剤が介在する場合、加圧後、正極活物質や固体電解質と第一結着剤との接触面積が増大する。これにより粒子間の結着性を良好にすることができる。すなわち本発明は、強い結着性を備える第一結着剤が正極合剤の溶媒に不溶性で、正極合剤中に粒子状あるいは塊状で存在し、得られる正極層内に該第一結着剤が非連続的に存在する場合であっても、正極活物質や固体電解質等の粒子間結着を強固に結着させることができる。   The first binder is sufficiently melted in the positive electrode layer by the pressure applied to the positive electrode layer when forming the positive electrode layer or integrating the laminated structure of the all-solid-state secondary battery. Therefore, when the first binder is interposed between the positive electrode active material and the solid electrolyte particles, the contact area between the positive electrode active material or solid electrolyte and the first binder increases after pressurization. Thereby, the binding property between the particles can be improved. That is, according to the present invention, the first binder having a strong binding property is insoluble in the solvent of the positive electrode mixture and exists in the positive electrode mixture in the form of particles or lumps, and the first binder is obtained in the obtained positive electrode layer. Even when the agent is present discontinuously, the binding between particles such as the positive electrode active material and the solid electrolyte can be firmly bound.

加圧により、第一結着剤を十分に融解させる観点から、第一結着剤の平均粒子径は、0.01〜10μmが好ましく、0.1〜5μmがより好ましい。平均粒子径が10μmを超える場合、第一結着剤の融解が不十分になり、第一結着剤による結着効果を十分に発揮させることが困難である。平均粒子径は、任意に選び出した50個の第一結着剤の粒子径を乾式粒度分布測定装置を用いて測定し、その平均値を平均粒子径とした。   From the viewpoint of sufficiently melting the first binder by pressurization, the average particle diameter of the first binder is preferably 0.01 to 10 μm, and more preferably 0.1 to 5 μm. When the average particle diameter exceeds 10 μm, the melting of the first binder becomes insufficient, and it is difficult to sufficiently exhibit the binding effect of the first binder. The average particle size was determined by measuring the particle size of 50 first binders arbitrarily selected using a dry particle size distribution measuring apparatus, and taking the average value as the average particle size.

本発明に用いられる第二結着剤は、正極合剤の溶媒に可溶性であって、正極合剤内に均質に分散させることができる結着剤が好ましい。そのような結着剤を第二結着剤として用いると、正極層内に第二結着剤を連続的に存在させることができる。これにより正極活物質や固体電解質の結着状態を維持することができ、第一結着剤の作用と併せて、電池の積層構造を強固にすることができる。   The second binder used in the present invention is preferably a binder that is soluble in the solvent of the positive electrode mixture and can be uniformly dispersed in the positive electrode mixture. When such a binder is used as the second binder, the second binder can be continuously present in the positive electrode layer. Thereby, the binding state of the positive electrode active material and the solid electrolyte can be maintained, and the battery stack structure can be strengthened together with the action of the first binder.

第二結着剤は、炭化水素系高分子であることが好ましい。該炭化水素系高分子の分子量は、100〜100000が好ましく、1000〜10000がより好ましい。分子量が100より小さい場合、十分な結着力が得られないため好ましくない。分子量が100000を超える場合、スラリーの粘度が高くなりすぎて塗布が困難になるため好ましくない。第二結着剤の具体例としては、SBR、ブタジエンゴム(BR)、ニトリルゴム(NBR)、スチレンブタジエンブロック重合体(SBS)、スチレンエチレンブタジエンスチレンブロック重合体(SEB)、スチレン−(スチレンブタジエン)−スチレンブロック重合体などのスチレン系熱可塑性エラストマー類、天然ゴム(NR)、イソプレンゴム(IR)、エチレン−プロピレン−ジエン三元共重合体(EPDM)等が挙げられる。   The second binder is preferably a hydrocarbon polymer. The molecular weight of the hydrocarbon polymer is preferably 100 to 100,000, more preferably 1,000 to 10,000. A molecular weight of less than 100 is not preferable because sufficient binding force cannot be obtained. A molecular weight exceeding 100,000 is not preferable because the viscosity of the slurry becomes too high and coating becomes difficult. Specific examples of the second binder include SBR, butadiene rubber (BR), nitrile rubber (NBR), styrene butadiene block polymer (SBS), styrene ethylene butadiene styrene block polymer (SEB), and styrene- (styrene butadiene). ) -Styrenic thermoplastic elastomers such as styrene block polymer, natural rubber (NR), isoprene rubber (IR), ethylene-propylene-diene terpolymer (EPDM) and the like.

図2に示されるような、非連続的に存在する第一結着剤と連続的に存在する第二結着剤とを含有する正極層を形成するためには、SP値が異なる2種類の結着剤を第一結着剤と第二結着剤として用いる。本発明においてSP値とは、Hoy法により算出された溶解度パラメータをいう。   In order to form a positive electrode layer containing a first binder that is discontinuously present and a second binder that is continuously present, as shown in FIG. A binder is used as the first binder and the second binder. In the present invention, the SP value refers to a solubility parameter calculated by the Hoy method.

式(1)で表される構成単位を有する第一結着剤のSP値と第二結着剤のSP値との差の絶対値は、3以上であることが好ましい。式(2)で表される構成単位を有する第一結着剤のSP値と第二結着剤のSP値との差の絶対値は、1以上であることが好ましい。上記の第一結着剤の種類による第二結着剤のSP値との差の絶対値の好ましい範囲の相違は、式(1)で表される構成単位を有する第一結着剤と、式(2)で表される構成単位を有する第一結着剤とでは、同じ非極性溶媒に添加した場合のSP値の分布が異なることによる。   The absolute value of the difference between the SP value of the first binder having the structural unit represented by formula (1) and the SP value of the second binder is preferably 3 or more. The absolute value of the difference between the SP value of the first binder having the structural unit represented by formula (2) and the SP value of the second binder is preferably 1 or more. The difference in the preferable range of the absolute value of the difference from the SP value of the second binder due to the type of the first binder is the first binder having the structural unit represented by the formula (1), This is because the SP value distribution when added to the same nonpolar solvent is different from that of the first binder having the structural unit represented by the formula (2).

式(1)または式(2)で表される構成単位を有する第一結着剤を用いる場合、いずれにおいても第一結着剤のSP値と第二結着剤のSP値との差の絶対値が、上記の好ましい下限値に満たない場合、第一結着剤と第二結着剤が同一の溶媒に溶解し、上記構造を形成することができない。   When using the first binder having the structural unit represented by the formula (1) or formula (2), the difference between the SP value of the first binder and the SP value of the second binder in any case When the absolute value is less than the preferable lower limit, the first binder and the second binder are dissolved in the same solvent, and the structure cannot be formed.

上記のSP値差の絶対値は大きいほど、第一結着剤が非連続的に存在し第二結着剤が連続的に存在する本発明の構造を形成しやすい。そのため該SP値差の絶対値の上限は制限されない。ただし、各結着剤の入手容易性、取扱性等の観点から選択されうる第一結着剤と第二結着剤との種類を踏まえると、式(1)で表される構成単位を有する第一結着剤と第二結着剤とのSP値差の絶対値は、3以上25以下となることがより好ましい。式(2)で表される構成単位を有する第一結着剤と第二結着剤とのSP値差の絶対値は、1以上25以下となることがより好ましい。   The larger the absolute value of the SP value difference, the easier it is to form the structure of the present invention in which the first binder is discontinuously present and the second binder is continuously present. Therefore, the upper limit of the absolute value of the SP value difference is not limited. However, in consideration of the types of the first binder and the second binder that can be selected from the viewpoints of availability, handling, etc. of each binder, it has a structural unit represented by the formula (1). The absolute value of the SP value difference between the first binder and the second binder is more preferably 3 or more and 25 or less. The absolute value of the SP value difference between the first binder and the second binder having the structural unit represented by the formula (2) is more preferably 1 or more and 25 or less.

本発明の正極層の形成方法は限定されないが、好ましい方法として、スラリー状の正極合剤を集電体上に塗布後、乾燥させて溶媒を除去する方法がある。正極合剤は、溶媒中で正極活物質と固体電解質と第一結着剤と第二結着剤とを混合させて調製される。第一結着剤と第二結着剤とは、上記の所定の範囲内でSP値が異なる。第一結着剤と第二結着剤のSP値の相違を溶媒のSP値との相対性で表すと、第一結着剤と溶媒とのSP値差の絶対値が、第二結着剤と溶媒とのSP値差の絶対値より大きいと表現できる。すなわち、第一結着剤は第二結着剤と比較すると溶媒に溶解しにくく、溶媒に全く溶解しないか、溶け残る。一方、第二結着剤は溶媒に溶解する。そのような正極合剤スラリーを用いて正極層を形成することにより、正極層内に第一結着剤を非連続的に存在させ、第二結着剤を連続的に存在させることができる。   The method for forming the positive electrode layer of the present invention is not limited, but as a preferred method, there is a method in which a slurry-like positive electrode mixture is applied on a current collector and then dried to remove the solvent. The positive electrode mixture is prepared by mixing a positive electrode active material, a solid electrolyte, a first binder, and a second binder in a solvent. The first binder and the second binder have different SP values within the predetermined range. When the difference in SP value between the first binder and the second binder is expressed by the relativity with the SP value of the solvent, the absolute value of the SP value difference between the first binder and the solvent is the second binder. It can be expressed as being larger than the absolute value of the SP value difference between the agent and the solvent. That is, the first binder is less soluble in the solvent than the second binder, and is not dissolved in the solvent at all or remains undissolved. On the other hand, the second binder is dissolved in the solvent. By forming a positive electrode layer using such a positive electrode mixture slurry, the first binder can be discontinuously present in the positive electrode layer, and the second binder can be present continuously.

正極合剤に用いられる溶媒としては、正極合剤をスラリー状に維持する観点から、トルエンやキシレン等の非極性溶媒が好ましい。非極性溶媒のSP値は、5〜19〔MPa1/2〕程度である。したがって、第一結着剤は、そのSP値が20〔MPa1/2〕以上のものが好ましく、21〔MPa1/2〕以上のものがより好ましい。第一結着剤のSP値に上限はないが、第一結着剤と第二結着剤とのSP値差が大きすぎると相分離が生じて均一に分散しにくいため、30〔MPa1/2〕以下のものが好ましく用いられる。 The solvent used for the positive electrode mixture is preferably a nonpolar solvent such as toluene or xylene from the viewpoint of maintaining the positive electrode mixture in a slurry state. The SP value of the nonpolar solvent is about 5 to 19 [MPa 1/2 ]. Accordingly, the first binder preferably has an SP value of 20 [MPa 1/2 ] or more, and more preferably 21 [MPa 1/2 ] or more. There is no upper limit to the SP value of the first binder, since it is difficult if SP value difference between the first binder and the second binder is too large phase separation is uniformly dispersed occur, 30 [MPa 1 / 2 ] The following are preferably used.

第二結着剤は、そのSP値と、用いられる非極性溶媒のSP値とのSP値差の絶対値が好ましくは0以上15以下であり、より好ましくは0以上10以下であるものが選択される。上記のSP値差の絶対値が15を超えると、第二結着剤が非極性溶媒に溶解しにくくなる。該SP値差の絶対値が0に近くなるほど、第二結着剤が非極性溶媒に溶解しやすい。そのような第二結着剤としては、SP値が5〔MPa1/2〕以上20〔MPa1/2〕未満のものが好ましく、10〔MPa1/2〕以上19.5〔MPa1/2〕未満のものがより好ましく、10〔MPa1/2〕以上19〔MPa1/2〕未満のものが特に好ましい。本発明に用いられる第一結着剤と第二結着剤とは、各SP値とスラリーの溶媒のSP値との差が異なっており、かつ、上記のそれぞれ好ましい範囲のSP値を備えるものが選択される。 The second binder is selected such that the absolute value of the SP value difference between the SP value and the SP value of the nonpolar solvent used is preferably 0 or more and 15 or less, more preferably 0 or more and 10 or less. Is done. When the absolute value of the above SP value difference exceeds 15, the second binder becomes difficult to dissolve in the nonpolar solvent. The closer the absolute value of the SP value difference is to 0, the easier the second binder is dissolved in the nonpolar solvent. Such a second binder preferably has an SP value of 5 [MPa 1/2 ] or more and less than 20 [MPa 1/2 ], 10 [MPa 1/2 ] or more and 19.5 [MPa 1/2 ]. Those having a viscosity of less than 10 [MPa 1/2 ] and less than 19 [MPa 1/2 ] are particularly preferable. The first binder and the second binder used in the present invention are different from each other in SP value and SP value of the solvent of the slurry, and have SP values in the respective preferable ranges. Is selected.

本発明の正極層には、上記の第一結着剤と第二結着剤との他に、固体電解質、正極活物質が含まれる。その他導電助剤を含有させてもよい。正極層に含有される固体電解質は、従来公知のものを制限なく用いることができる。具体的には、LiN、LISICON、リン酸リチウムオキシナイトライド(LIPON)、Thio−LISICON(Li3.25Ge0.250.75)、LiO−Al−TiO−PSO(LATP)等が挙げられる。また高イオン伝導性を備える固体電解質として、LiPS、Li11、LiPSCl、LiPSなどが挙げられる。LiPSのイオン伝導度は、10−4〜10−3S/cmである。Li11のイオン伝導度は、10−3〜10−2S/cmである。LiPSClのイオン伝導度は、10−4〜10−3S/cmである。LiPSのイオン伝導度は、10−5〜10−4S/cmである。 The positive electrode layer of the present invention contains a solid electrolyte and a positive electrode active material in addition to the first binder and the second binder. In addition, you may contain a conductive support agent. As the solid electrolyte contained in the positive electrode layer, a conventionally known one can be used without limitation. Specifically, Li 3 N, LISICON, lithium phosphate oxynitride (LIPON), Thio-LISICON ( Li 3.25 Ge 0.25 P 0.75 S 4), Li 2 O-Al 2 O 3 - TiO 2 -P 2 SO 5 (LATP ) , and the like. Examples of the solid electrolyte having high ionic conductivity include Li 3 PS 4 , Li 7 P 3 S 11 , Li 6 PS 5 Cl, Li 3 PS 4, and the like. The ionic conductivity of Li 3 PS 4 is 10 −4 to 10 −3 S / cm. The ionic conductivity of Li 7 P 3 S 11 is 10 −3 to 10 −2 S / cm. The ionic conductivity of Li 6 PS 5 Cl is 10 −4 to 10 −3 S / cm. The ionic conductivity of Li 3 PS 4 is 10 −5 to 10 −4 S / cm.

本発明の正極層に含有される正極活物質は、リチウムイオンを可逆的に吸蔵し、放出できるものを制限なく用いることができる。具体的にはコバルト酸リチウム(LCO)、ニッケル酸リチウム、ニッケルコバルト酸リチウム、ニッケルコバルトアルミニウム酸リチウム(NCA)、ニッケルコバルトマンガン酸リチウム(NCM)、マンガン酸リチウム、ニッケルマンガン酸リチウム、リン酸鉄リチウムなどが挙げられる。これら正極活物質のうち、層状岩塩型構造を有する遷移金属酸化物のリチウム塩が好ましい。   As the positive electrode active material contained in the positive electrode layer of the present invention, a material capable of reversibly occluding and releasing lithium ions can be used without limitation. Specifically, lithium cobaltate (LCO), lithium nickelate, lithium nickel cobaltate, nickel cobalt lithium aluminumate (NCA), nickel cobalt lithium manganate (NCM), lithium manganate, nickel nickel manganate, iron phosphate Examples include lithium. Of these positive electrode active materials, lithium salts of transition metal oxides having a layered rock salt structure are preferable.

正極層100質量部における上記の成分の含有量について、正極活物質は、40〜99質量部が好ましく、50〜95質量部がより好ましい。固体電解質は、1〜50質量部が好ましく、1〜45質量部がより好ましく、5〜40質量部がさらに好ましい。第一結着剤は、0.05〜10質量部が好ましく、0.4〜9質量部がより好ましく、0.5〜8質量部がさらに好ましく、0.5〜6質量部が特に好ましい。第二結着剤は、0.05〜5質量部が好ましく、0.2〜3質量部がより好ましい。上記の好ましい範囲内で各成分を含有させることにより、イオン伝導性が良好で各粒子の結着性に優れた正極層を形成することができる。   About content of said component in 100 mass parts of positive electrode layers, 40-99 mass parts is preferable, and, as for a positive electrode active material, 50-95 mass parts is more preferable. The solid electrolyte is preferably 1 to 50 parts by mass, more preferably 1 to 45 parts by mass, and even more preferably 5 to 40 parts by mass. The first binder is preferably 0.05 to 10 parts by mass, more preferably 0.4 to 9 parts by mass, further preferably 0.5 to 8 parts by mass, and particularly preferably 0.5 to 6 parts by mass. The second binder is preferably 0.05 to 5 parts by mass, and more preferably 0.2 to 3 parts by mass. By including each component within the above preferred range, a positive electrode layer having good ion conductivity and excellent binding property of each particle can be formed.

正極層には、さらに導電助剤を含有させてもよい。導電助剤としては、黒鉛、カーボンブラック、アセチレンブラック、ケッチェンブラック、炭素繊維、金属粉等が好ましく用いられる。   The positive electrode layer may further contain a conductive additive. As the conductive aid, graphite, carbon black, acetylene black, ketjen black, carbon fiber, metal powder, and the like are preferably used.

[負極層]
本発明の負極層は、少なくとも負極活物質と固体電解質とを含有し、さらに第一結着剤と第二結着剤とのいずれか又は両方を含有する。さらに導電助剤等を含有しうる。第一結着剤と第二結着剤とを含有する場合、該負極層においては第一結着剤が非連続的に存在し、第二結着剤が連続的に存在する。本発明に用いられる負極活物質としては、単体金属や合金、金属を含有した導電性材料等の金属イオンを吸蔵および放出しうる公知の物質を制限なく用いることができる。金属リチウムや、リチウム、インジウム、スズ、アルミ、ケイ素等の金属およびこれらの合金、Li4/3Ti5/3、SnO等の遷移金属酸化物を用いることが好ましい。リチウムイオンを常法に従ってプレドープさせた炭素材料も好ましい。そのような炭素材料としては、黒鉛等リチウムイオンと共に層間化合物を形成するものが好ましい。上記の負極活物質は単独で用いてもよく併用してもよい。
[Negative electrode layer]
The negative electrode layer of the present invention contains at least a negative electrode active material and a solid electrolyte, and further contains either or both of a first binder and a second binder. Furthermore, a conductive auxiliary agent or the like can be contained. When the first binder and the second binder are contained, the first binder is discontinuously present in the negative electrode layer, and the second binder is continuously present. As the negative electrode active material used in the present invention, a known substance that can occlude and release metal ions, such as a single metal, an alloy, or a conductive material containing a metal, can be used without limitation. It is preferable to use metallic lithium, metals such as lithium, indium, tin, aluminum and silicon, and alloys thereof, and transition metal oxides such as Li 4/3 Ti 5/3 O 4 and SnO. A carbon material pre-doped with lithium ions according to a conventional method is also preferable. As such a carbon material, what forms an intercalation compound with lithium ions, such as graphite, is preferable. Said negative electrode active material may be used independently, and may be used together.

負極層に含有される固体電解質と第一結着剤と第二結着剤とは、上記に説明した正極層に含有されうるものと同じものを用いることができる。負極層100質量部における上記の成分の含有量について、負極活物質は、40〜99質量部が好ましく、50〜95質量部がより好ましい。固体電解質は、1〜50質量部が好ましく、1〜45質量部がより好ましく、5〜40質量部がさらに好ましい。第一結着剤は、0.05〜15質量部が好ましく、0.1〜10質量部がより好ましく、0.5〜8質量部がより好ましい。第二結着剤は、0.05〜5質量部が好ましく、0.1〜5質量部がより好ましく、0.2〜3質量部がより好ましい。上記の好ましい範囲内で各成分を含有させることにより、イオン伝導性が良好で各粒子の結着性に優れた負極層を形成することができる。   The same thing as what can be contained in the positive electrode layer demonstrated above can be used for the solid electrolyte contained in a negative electrode layer, a 1st binder, and a 2nd binder. About content of said component in 100 mass parts of negative electrode layers, 40-99 mass parts is preferable, and, as for a negative electrode active material, 50-95 mass parts is more preferable. The solid electrolyte is preferably 1 to 50 parts by mass, more preferably 1 to 45 parts by mass, and even more preferably 5 to 40 parts by mass. 0.05-15 mass parts is preferable, as for a 1st binder, 0.1-10 mass parts is more preferable, and 0.5-8 mass parts is more preferable. The second binder is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 5 parts by mass, and more preferably 0.2 to 3 parts by mass. By including each component within the above preferred range, a negative electrode layer having good ion conductivity and excellent binding properties of each particle can be formed.

[固体電解質層]
本発明の固体電解質層は、第一結着剤と第二結着剤とのいずれか又は両方と固体電解質を含有する。第一結着剤と第二結着剤とを含有する場合、該固体電解質層においては第一結着剤が非連続的に存在し、第二結着剤が連続的に存在する。固体電解質としては、従来公知のものを用いることができ、好ましくはイオン伝導性に優れる硫化物固体電解質が用いられる。具体的には、LiN、LISICON、リン酸リチウムオキシナイトライド(LIPON)、Thio−LISICON(Li3.25Ge0.250.75)、LiO−Al−TiO−PSO(LATP)等が挙げられる。また硫化物固体電解質としては、LiPS、Li11、LiPSCl等が好ましく用いられる。本発明に用いられる硫化物固体電解質のイオン伝導度は高いほど好ましいが、少なくとも10−4〜10−2S/cmである。10−4S/cmより低い場合は、充放電容量が著しく低下する。LiPSのイオン伝導度は、10−4〜10−3S/cmであり、Li11のイオン伝導度は、10−3〜10−2S/cmであり、LiPSClのイオン伝導度は、10−4〜10−3S/cmである。
[Solid electrolyte layer]
The solid electrolyte layer of the present invention contains either or both of the first binder and the second binder and the solid electrolyte. When the first binder and the second binder are contained, the first binder is discontinuously present and the second binder is continuously present in the solid electrolyte layer. As the solid electrolyte, a conventionally known one can be used, and a sulfide solid electrolyte excellent in ion conductivity is preferably used. Specifically, Li 3 N, LISICON, lithium phosphate oxynitride (LIPON), Thio-LISICON ( Li 3.25 Ge 0.25 P 0.75 S 4), Li 2 O-Al 2 O 3 - TiO 2 -P 2 SO 5 (LATP ) , and the like. As the sulfide solid electrolyte, Li 3 PS 4, Li 7 P 3 S 11, Li 6 PS 5 Cl , and the like are preferably used. The higher the ionic conductivity of the sulfide solid electrolyte used in the present invention, the better, but it is at least 10 −4 to 10 −2 S / cm. When it is lower than 10 −4 S / cm, the charge / discharge capacity is significantly reduced. The ionic conductivity of Li 3 PS 4 is 10 −4 to 10 −3 S / cm, the ionic conductivity of Li 7 P 3 S 11 is 10 −3 to 10 −2 S / cm, and Li 6 The ionic conductivity of PS 5 Cl is 10 −4 to 10 −3 S / cm.

硫化物固体電解質は、LiSとPとを50:50〜80:20の混合比で混合させることで得ることができる。上記の好ましい混合比を超える場合、得られる硫化物固体電解質が所望のイオン伝導度を備えないため好ましくない。他の成分として、SiS、GeS、B等を含有させることでさらにイオン伝導度を向上させることができる。該硫化物固体電解質は、非晶質、結晶体のいずれでもよいが、非晶質のものが活物質と良好な接触性をもつため好ましく用いられる。 The sulfide solid electrolyte can be obtained by mixing Li 2 S and P 2 S 5 at a mixing ratio of 50:50 to 80:20. When the preferable mixing ratio is exceeded, the obtained sulfide solid electrolyte does not have a desired ionic conductivity, which is not preferable. By adding SiS 2 , GeS 2 , B 2 S 3, etc. as other components, the ionic conductivity can be further improved. The sulfide solid electrolyte may be either amorphous or crystalline, but an amorphous one is preferably used because it has good contact with the active material.

混合法としてはメカニカルミリング法(MM法)や溶液法を適用することができる。MM法とは、反応器内に上記の出発原料とボールミル等を入れ強撹拌し、出発原料を微粒子化して混合させる方法である。溶液法を用いる場合は、溶媒内で出発原料を混合させて析出物として固体電解質を得ることができる。   As the mixing method, a mechanical milling method (MM method) or a solution method can be applied. The MM method is a method in which the above starting material and a ball mill are placed in a reactor and vigorously stirred to make the starting material fine particles and mix them. When the solution method is used, a solid electrolyte can be obtained as a precipitate by mixing starting materials in a solvent.

[全固体二次電池の製造方法]
本発明の全固体電池の製造方法は、本発明の作用効果を得られる限り制限されない。製造方法の好ましい例としては以下の製造方法がある。すなわち、まず集電体上に正極合剤または負極合剤を塗布、乾燥させて正極層と負極層を作製し、正極層と負極層との間に固体電解質層を挟持させて積層体を形成し、該積層体を加圧成形して一体化させる方法である。
[Method for producing all-solid-state secondary battery]
The manufacturing method of the all-solid-state battery of this invention is not restrict | limited as long as the effect of this invention is acquired. Preferred examples of the production method include the following production methods. That is, first, a positive electrode mixture or a negative electrode mixture is applied onto a current collector and dried to produce a positive electrode layer and a negative electrode layer, and a solid electrolyte layer is sandwiched between the positive electrode layer and the negative electrode layer to form a laminate. In this method, the laminate is formed by pressure molding.

本発明は、第一結着剤を非連続的に存在させ、第二結着材を連続的に存在させることができる、所定の正極合剤調整工程と負極合剤調整工程と固体電解質層形成工程とのいずれか一つ以上の工程を含む。   The present invention provides a predetermined positive electrode mixture adjustment step, a negative electrode mixture adjustment step, and a solid electrolyte layer formation in which the first binder can be discontinuously present and the second binder can be continuously present. Any one or more of the steps.

[正極合剤調整工程]
本発明に用いられる正極合剤は、非極性溶媒に、正極活物質と固体電解質と非極性溶媒不溶性の第一結着剤と非極性溶媒可溶性の第二結着剤とを添加し混練させることにより調製される。該正極合剤に添加する固体電解質としては、全固体二次電池に用いられる従来公知の固体電解質を制限することなく用いることができ、上記に説明した硫化物固体電解質がイオン伝導性に優れるため好ましい。正極活物質としては、上記に説明した従来公知の正極活物質を添加することができる。
[Positive electrode mixture adjustment process]
The positive electrode mixture used in the present invention is prepared by adding a positive electrode active material, a solid electrolyte, a nonpolar solvent-insoluble first binder and a nonpolar solvent-soluble second binder to a nonpolar solvent and kneading them. It is prepared by. As the solid electrolyte to be added to the positive electrode mixture, conventionally known solid electrolytes used for all-solid secondary batteries can be used without limitation, and the sulfide solid electrolyte described above is excellent in ion conductivity. preferable. As a positive electrode active material, the conventionally well-known positive electrode active material demonstrated above can be added.

本発明の全固体二次電池用正極合剤の溶媒は、極性溶媒と非極性溶媒とのいずれも用いることができ、好ましくは非極性溶媒が用いられる。非極性溶媒を用いることで、正極合剤に硫化物固体電解質を添加させても、正極合剤のハンドリング性を良好に保つことができる。また、極性溶媒に硫化物固体電解質を添加して調整された正極合剤において生じる問題を回避できる。すなわち、極性溶媒を用いる正極合剤による場合、正極合剤の塗布および乾燥工程を含む正極形成工程中に、極性溶媒と硫化物固体電解質との反応が進み、硫化物固体電解質のリチウムイオン伝導度を低下させる。これに対し、非極性溶媒では、上記のような反応が生じないため、正極合剤に添加された硫化物固体電解質を、そのまま正極層に含有させることができ、全固体二次電池のイオン伝導度の抑制を防止できる。非極性溶媒の具体例としては、トルエン、キシレン、エチルベンゼン等の芳香族炭化水素、ペンタン、ヘキサン、ヘプタン等の脂肪族炭化水素類等が挙げられる。   As the solvent for the positive electrode mixture for an all-solid secondary battery of the present invention, both a polar solvent and a nonpolar solvent can be used, and a nonpolar solvent is preferably used. By using a nonpolar solvent, even if a sulfide solid electrolyte is added to the positive electrode mixture, the handling property of the positive electrode mixture can be kept good. Moreover, the problem which arises in the positive mix prepared by adding sulfide solid electrolyte to a polar solvent can be avoided. That is, in the case of the positive electrode mixture using a polar solvent, the reaction between the polar solvent and the sulfide solid electrolyte proceeds during the positive electrode formation step including the application and drying steps of the positive electrode mixture, and the lithium ion conductivity of the sulfide solid electrolyte is increased. Reduce. On the other hand, since the reaction as described above does not occur in the nonpolar solvent, the sulfide solid electrolyte added to the positive electrode mixture can be contained in the positive electrode layer as it is, and the ionic conduction of the all-solid secondary battery. The degree of control can be prevented. Specific examples of the nonpolar solvent include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene, and aliphatic hydrocarbons such as pentane, hexane, and heptane.

第二結着剤としては、非極性溶媒可溶性の結着剤が用いられる。本発明において「非極性溶媒可溶性」とは、非極性溶媒に添加したときに完全に溶解し溶媒内に均質に分散させうることを意味し、溶媒として選択された非極性溶媒のSP値と第二結着剤のSP値とのSP値差の絶対値が、好ましくは0以上15未満であり、より好ましくは0以上10未満であり、さらに好ましくは0以上5未満であることを包含する。かかる結着剤は溶媒に均質に分散させることができ、得られる正極層内のいずれの領域においても正極活物質や固体電解質を良好に結着させることができる。   As the second binder, a nonpolar solvent-soluble binder is used. In the present invention, “non-polar solvent-soluble” means that when added to a non-polar solvent, it is completely dissolved and can be homogeneously dispersed in the solvent. The absolute value of the SP value difference from the SP value of the binder is preferably 0 or more and less than 15, more preferably 0 or more and less than 10, and further preferably 0 or more and less than 5. Such a binder can be homogeneously dispersed in a solvent and can favorably bind the positive electrode active material and the solid electrolyte in any region in the obtained positive electrode layer.

非極性溶媒に効率よく溶解させる観点からは、上記のSP値差の絶対値が0以上5未満となる第二結着剤を用いることが好ましい。ただし、用いられる非極性溶媒とのSP値差の絶対値が0以上15未満となる第二結着剤である場合は、温度条件等を適宜調整することにより、その第二結着剤は非極性溶媒に溶解させることができる。第二結着剤の具体例としては、SBR、BR、NBR、SBS、SEB、スチレン−(スチレンブタジエン)−スチレンブロック重合体などのスチレン系熱可塑性エラストマー類が挙げられる。   From the viewpoint of efficiently dissolving in a nonpolar solvent, it is preferable to use a second binder in which the absolute value of the SP value difference is 0 or more and less than 5. However, when the second binder has an SP value difference of 0 or more and less than 15 with respect to the nonpolar solvent used, the second binder is non-adjusted by appropriately adjusting temperature conditions and the like. It can be dissolved in a polar solvent. Specific examples of the second binder include styrene-based thermoplastic elastomers such as SBR, BR, NBR, SBS, SEB, and styrene- (styrene butadiene) -styrene block polymer.

第一結着剤としては、非極性溶媒可溶性の結着剤が用いられる。本発明において「非極性溶媒不溶性」とは、非極性溶媒に添加したときに、溶解せず、または完全に溶解しきらず溶け残ることを意味し、溶媒として選択された非極性溶媒のSP値と第一結着剤のSP値とのSP値差の絶対値が、好ましくは5以上であり、より好ましくは10以上であることを包含する。上記のSP値差の絶対値が大きいほど、第一結着剤は、用いられる非極性溶媒に溶けにくく正極合剤のスラリー中で粒子として点在する。非極性溶媒中でできるだけ溶解させ、正極合剤中に粒径の小さな第一結着剤粒子を存在させる観点からは、本発明に用いられる第一結着剤は、上記の非極性溶媒とのSP値差の絶対値が、10以上30以下のものが好ましく選択される。   As the first binder, a nonpolar solvent-soluble binder is used. In the present invention, “non-polar solvent insoluble” means that when added to a non-polar solvent, it does not dissolve or does not completely dissolve and remains undissolved, and the SP value of the non-polar solvent selected as the solvent The absolute value of the SP value difference from the SP value of the first binder is preferably 5 or more, more preferably 10 or more. The greater the absolute value of the SP value difference, the more difficult the first binder is to dissolve in the nonpolar solvent used, and the particles are scattered as particles in the slurry of the positive electrode mixture. From the viewpoint of dissolving as much as possible in a nonpolar solvent and allowing the first binder particles having a small particle size to be present in the positive electrode mixture, the first binder used in the present invention is The absolute value of the SP value difference is preferably selected from 10 to 30.

第二結着剤と非極性溶媒とのSP値差と、第一結着剤と非極性溶媒とのSP値差との各絶対値が近似する場合、第一結着剤と第二結着剤との非極性溶媒に対する溶解性はほとんど変わらない。本発明においては、第一結着剤は、第二結着剤を溶解させた非極性溶媒に添加させることが好ましい。そのような添加順序にすることにより、本発明所定の第一結着剤が非連続的に存在し、第二結着剤が連続的に存在する態様を形成しやすくなる。   When the absolute values of the SP value difference between the second binder and the nonpolar solvent and the SP value difference between the first binder and the nonpolar solvent approximate, the first binder and the second binder The solubility of the agent in a nonpolar solvent is hardly changed. In the present invention, the first binder is preferably added to a nonpolar solvent in which the second binder is dissolved. By adopting such an addition order, it becomes easy to form an embodiment in which the predetermined first binder of the present invention is discontinuously present and the second binder is continuously present.

非極性溶媒と第一結着剤とのSP値差の絶対値と、非極性溶媒と第二結着剤とのSP値差の絶対値とが、それぞれ上記の所定の範囲内になるように非極性溶媒と第一結着剤と第二結着剤とを選択することにより、結果として第一結着剤と第二結着剤とのSP値差の絶対値は、1以上25以下になる。   The absolute value of the SP value difference between the nonpolar solvent and the first binder and the absolute value of the SP value difference between the nonpolar solvent and the second binder are within the above predetermined ranges, respectively. By selecting the nonpolar solvent, the first binder, and the second binder, the absolute value of the SP value difference between the first binder and the second binder is 1 or more and 25 or less as a result. Become.

上記の第一結着剤としては、上記式(1)で表される構成単位を有する化合物が好ましい。具体例としては、PVdFが挙げられる。また上記式(2)で表される構成単位を有する化合物を用いてもよい。具体例としてはPVAが挙げられる。その他の具体例としては、ポリアクリル酸エステルの共重合体、VDF−HFPおよびそれらのカルボン酸変性物、塩素化ポリエチレン、ポリメタクリル酸エステル、エチレン−ビニルアルコール共重合体、ポリイミド、ポリアミド、ポリアミドイミド等が挙げられる。該化合物の分子量は、1×10〜1×10が好ましく、2×10〜8×10がより好ましい。上記に例示した第一結着剤は、第二結着剤として例示したSBR、BR、NBR、SBS、SEB、スチレン−(スチレンブタジエン)−スチレンブロック重合体などのスチレン系熱可塑性エラストマー類より結着性が強い。 As said 1st binder, the compound which has a structural unit represented by the said Formula (1) is preferable. A specific example is PVdF. Moreover, you may use the compound which has a structural unit represented by the said Formula (2). A specific example is PVA. Other specific examples include polyacrylate copolymers, VDF-HFP and their carboxylic acid modified products, chlorinated polyethylene, polymethacrylate esters, ethylene-vinyl alcohol copolymers, polyimides, polyamides, polyamideimides Etc. The molecular weight of the compound is preferably 1 × 10 5 to 1 × 10 7 and more preferably 2 × 10 5 to 8 × 10 6 . The first binder exemplified above is bound from styrene thermoplastic elastomers such as SBR, BR, NBR, SBS, SEB, styrene- (styrene butadiene) -styrene block polymer exemplified as the second binder. Strong wearability.

第一結着剤の粒子の平均粒子径は、0.01〜10μmが好ましく、0.1〜5μmがより好ましい。かかる粒子径を備える第一結着剤が正極活物質や固体電解質の粒子間に介在する場合、正極合剤を用いて作製した正極層が加圧されることにより、第一結着剤は、該粒子間で融解して該粒子間の接触面に拡がり、正極活物質や固体電解質を強固に結着させることができる。そのため、第一結着剤は、正極合剤中で均質に分散させることができなくても、正極層と他の層との接合に大きく寄与する。これにより、全固体二次電池の積層構造の層間剥離を防止し、製品寿命を向上させることができる。   The average particle size of the first binder particles is preferably 0.01 to 10 μm, and more preferably 0.1 to 5 μm. When the first binder having such a particle size is interposed between particles of the positive electrode active material or the solid electrolyte, the first binder is produced by pressurizing the positive electrode layer produced using the positive electrode mixture, It melts between the particles and spreads to the contact surface between the particles, so that the positive electrode active material and the solid electrolyte can be firmly bound. Therefore, even if the first binder cannot be uniformly dispersed in the positive electrode mixture, it greatly contributes to the bonding between the positive electrode layer and other layers. Thereby, delamination of the laminated structure of the all-solid-state secondary battery can be prevented, and the product life can be improved.

各添加成分の添加量は用いられる正極活物質や固体電解質の比表面積に対応して適宜調節される。すなわち、正極活物質と固体電解質との比表面積に基づいて、正極活物質と固体電解質との接触面積を最大限確保できるように、正極活物質と固体電解質との添加量を調節する。また上記の確保しうる接触面積に対し十分な量の結着剤を添加する。   The addition amount of each additive component is appropriately adjusted according to the specific surface area of the positive electrode active material and solid electrolyte used. That is, based on the specific surface area between the positive electrode active material and the solid electrolyte, the addition amount of the positive electrode active material and the solid electrolyte is adjusted so as to ensure the maximum contact area between the positive electrode active material and the solid electrolyte. A sufficient amount of the binder is added to the above-described contact area that can be secured.

例えば、比表面積の平均値が2m/gの固体電解質と、比表面積の平均値が0.1m/gの正極活物質と、本発明所定の第一結着剤と第二結着剤とを、非極性溶媒100質量部に添加する場合、該溶媒に各添加成分を添加して得られる正極合剤100質量部に対する各添加成分の添加量は、正極活物質は49.9〜99質量部が好ましく、59.9〜95質量部がより好ましい。固体電解質は1〜50質量部が好ましく、5〜40質量部がより好ましい。第一結着剤は0.05〜7質量部が好ましく、0.1〜5質量部がより好ましい。第二結着剤は0.05〜2質量部が好ましく、0.1〜1質量部がより好ましい。 For example, a solid electrolyte of the average value of the specific surface area of 2m 2 / g, a positive electrode active material of the average value of the specific surface area of 0.1 m 2 / g, the present invention predetermined first binder and a second binder Is added to 100 parts by weight of the nonpolar solvent, the amount of each additive component added to 100 parts by weight of the positive electrode mixture obtained by adding each additive component to the solvent is 49.9 to 99 parts by weight of the positive electrode active material. Preferably, 59.9-95 mass parts is more preferable. The solid electrolyte is preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass. The first binder is preferably 0.05 to 7 parts by mass, and more preferably 0.1 to 5 parts by mass. The second binder is preferably 0.05 to 2 parts by mass, and more preferably 0.1 to 1 part by mass.

他の例として、比表面積の平均値が2m/gの固体電解質と、比表面積の平均値が1.0m/gの正極活物質と、本発明所定の第一結着剤と第二結着剤とを、上記の溶媒に添加する場合、正極合剤100質量部に対する各添加成分の添加量は、正極活物質は49.9〜99質量部が好ましく、59.9〜95質量部がより好ましい。固体電解質は1〜50質量部が好ましく、5〜40質量部がより好ましい。第一結着剤は0.05〜8質量部が好ましく、0.5〜6質量部がより好ましい。第二結着剤は0.05〜2質量部が好ましく、0.1〜1質量部がより好ましい。 As another example, a solid electrolyte of the average value of the specific surface area of 2m 2 / g, the positive electrode active material average value of specific surface area of 1.0 m 2 / g, the present invention predetermined first binder and the second binding When adding an adhesive agent to said solvent, 49.9-99 mass parts is preferable, and, as for the addition amount of each additive component with respect to 100 mass parts of positive electrode mixtures, 59.9-95 mass parts is more preferable. The solid electrolyte is preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass. The first binder is preferably 0.05 to 8 parts by mass, and more preferably 0.5 to 6 parts by mass. The second binder is preferably 0.05 to 2 parts by mass, and more preferably 0.1 to 1 part by mass.

他の例として、比表面積の平均値が2m/gの固体電解質と、比表面積の平均値が10.0m/gの正極活物質と、本発明所定の第一結着剤と第二結着剤とを、上記の溶媒に添加する場合、正極合剤100質量部に対する各添加成分の添加量は、正極活物質は49.5〜99質量部が好ましく、59.9〜95質量部がより好ましい。固体電解質は1〜50質量部が好ましく、5〜40質量部がより好ましい。第一結着剤は0.4〜9質量部が好ましく、0.5〜8質量部がより好ましい。第二結着剤は0.1〜3質量部が好ましく、0.2〜1.5質量部がより好ましい。 As another example, a solid electrolyte of the average value of the specific surface area of 2m 2 / g, the positive electrode active material average value of specific surface area of 10.0 m 2 / g, the present invention predetermined first binder and the second binding When adding an adhesive to said solvent, the addition amount of each additive component with respect to 100 parts by mass of the positive electrode mixture is preferably 49.5 to 99 parts by mass, more preferably 59.9 to 95 parts by mass for the positive electrode active material. The solid electrolyte is preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass. The first binder is preferably 0.4 to 9 parts by mass, and more preferably 0.5 to 8 parts by mass. The second binder is preferably 0.1 to 3 parts by mass, and more preferably 0.2 to 1.5 parts by mass.

他の例として、比表面積の平均値が10m/gの固体電解質と、比表面積の平均値が1.0m/gの正極活物質と、本発明所定の第一結着剤と第二結着剤とを、上記の溶媒に添加する場合、正極合剤100質量部に対する各添加成分の添加量は、正極活物質は49.5〜99質量部が好ましく、59.9〜95質量部がより好ましい。固体電解質は1〜50質量部が好ましく、5〜40質量部がより好ましい。第一結着剤は0.4〜9質量部が好ましく、0.5〜7質量部がより好ましい。第二結着剤は0.1〜3質量部が好ましく、0.2〜1.5質量部がより好ましい。 As another example, a solid electrolyte of the average value of the specific surface area of 10 m 2 / g, the positive electrode active material average value of specific surface area of 1.0 m 2 / g, the present invention predetermined first binder and the second binding When adding an adhesive to said solvent, the addition amount of each additive component with respect to 100 parts by mass of the positive electrode mixture is preferably 49.5 to 99 parts by mass, more preferably 59.9 to 95 parts by mass for the positive electrode active material. The solid electrolyte is preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass. The first binder is preferably 0.4 to 9 parts by mass, and more preferably 0.5 to 7 parts by mass. The second binder is preferably 0.1 to 3 parts by mass, and more preferably 0.2 to 1.5 parts by mass.

正極合剤は、ハンドリング性を良好に保つため、増粘剤や非極性溶媒量を調節して粘度調整を行う。正極合剤の粘度は、室温で5〜20Pa・sが好ましい。粘度が高すぎると正極合剤を均一な厚みで塗布することが困難になる。また粘度が低すぎると正極合剤が流動し、正極層を形成することができない。   The positive electrode mixture adjusts the viscosity by adjusting the amount of the thickener or the nonpolar solvent in order to keep the handling property good. The viscosity of the positive electrode mixture is preferably 5 to 20 Pa · s at room temperature. If the viscosity is too high, it is difficult to apply the positive electrode mixture with a uniform thickness. If the viscosity is too low, the positive electrode mixture flows and the positive electrode layer cannot be formed.

[負極合剤調製工程]
本発明で用いられる負極合剤は、上記の正極合剤調製工程において正極合剤の添加成分のうち正極活物質を負極活物質に変えることにより、他は正極合剤調製工程と同様にして調製することができる。負極合剤には、上記に説明した所定の非極性溶媒に負極活物質と固体電解質と、所定の第一結着剤と第二結着剤とが添加される。負極合剤の粘度は1〜15Pa・sが好ましい。これにより集電体に負極合剤を適切に塗布することができる。
[Negative electrode mixture preparation process]
The negative electrode mixture used in the present invention is prepared in the same manner as the positive electrode mixture preparation step by changing the positive electrode active material to the negative electrode active material among the additional components of the positive electrode mixture in the positive electrode mixture preparation step. can do. In the negative electrode mixture, a negative electrode active material, a solid electrolyte, a predetermined first binder, and a second binder are added to the predetermined nonpolar solvent described above. The viscosity of the negative electrode mixture is preferably 1 to 15 Pa · s. Thereby, the negative electrode mixture can be appropriately applied to the current collector.

各添加成分の添加量は用いられる負極活物質や固体電解質の比表面積に対応して適宜調節される。例えば、比表面積の平均値が2m/gの固体電解質と、比表面積の平均値が1m/gの負極活物質と、本発明所定の結着剤とを、非極性溶媒に添加する場合、該溶媒に各添加成分を添加して得られる負極合剤100質量部に対する各添加成分の添加量は、負極活物質は49.9〜99質量部が好ましく、59.9〜95質量部がより好ましい。固体電解質は1〜50質量部が好ましく、5〜40質量部がより好ましい。第一結着剤は0.05〜8質量部が好ましく、0.1〜7質量部がより好ましい。第二結着剤は0.05〜3質量部が好ましく、0.1〜2質量部がより好ましい。 The addition amount of each additive component is appropriately adjusted according to the specific surface area of the negative electrode active material and solid electrolyte used. For example, a solid electrolyte of the average value of the specific surface area of 2m 2 / g, a negative electrode active material of the mean value of the specific surface area of 1 m 2 / g, if the present invention a predetermined binder is added to the non-polar solvent The amount of each additive component added to 100 parts by mass of the negative electrode mixture obtained by adding each additive component to the solvent is preferably 49.9 to 99 parts by mass, more preferably 59.9 to 95 parts by mass for the negative electrode active material. The solid electrolyte is preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass. The first binder is preferably 0.05 to 8 parts by mass, and more preferably 0.1 to 7 parts by mass. The second binder is preferably 0.05 to 3 parts by mass, and more preferably 0.1 to 2 parts by mass.

他の例として、比表面積の平均値が2m/gの固体電解質と、比表面積の平均値が2m/gの負極活物質と、本発明所定の結着剤とを、上記の溶媒に添加する場合、負極合剤100質量部に対する各添加成分の添加量は、負極活物質は49.9〜99質量部が好ましく、59.5〜95質量部がより好ましい。固体電解質は1〜50質量部が好ましく、5〜40質量部がより好ましい。第一結着剤は0.05〜8質量部が好ましく、0.2〜7質量部がより好ましい。第二結着剤は0.05〜3質量部が好ましく、0.1〜2質量部がより好ましい。 As another example, a solid electrolyte of the average value of the specific surface area of 2m 2 / g, a negative electrode active material of the mean value of the specific surface area of 2m 2 / g, and the invention given binder to the solvent When added, the addition amount of each additive component with respect to 100 parts by mass of the negative electrode mixture is preferably 49.9 to 99 parts by mass, more preferably 59.5 to 95 parts by mass for the negative electrode active material. The solid electrolyte is preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass. The first binder is preferably 0.05 to 8 parts by mass, and more preferably 0.2 to 7 parts by mass. The second binder is preferably 0.05 to 3 parts by mass, and more preferably 0.1 to 2 parts by mass.

他の例として、比表面積の平均値が2m/gの固体電解質と、比表面積の平均値が10m/gの負極活物質と、本発明所定の結着剤とを、上記の溶媒に添加する場合、負極合剤100質量部に対する各添加成分の添加量は、負極活物質は49.5〜99質量部が好ましく、59.5〜95質量部がより好ましい。固体電解質は1〜50質量部が好ましく、5〜40質量部がより好ましい。第一結着剤は0.4〜9質量部が好ましく、0.5〜8質量部がより好ましい。第二結着剤は0.1〜5質量部が好ましく、0.2〜3質量部がより好ましい。 As another example, a solid electrolyte of the average value of the specific surface area of 2m 2 / g, a negative electrode active material of the mean value of the specific surface area of 10 m 2 / g, and the invention given binder to the solvent When adding, the addition amount of each additive component with respect to 100 parts by mass of the negative electrode mixture is preferably 49.5 to 99 parts by mass, more preferably 59.5 to 95 parts by mass for the negative electrode active material. The solid electrolyte is preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass. The first binder is preferably 0.4 to 9 parts by mass, and more preferably 0.5 to 8 parts by mass. The second binder is preferably 0.1 to 5 parts by mass, and more preferably 0.2 to 3 parts by mass.

他の例として、比表面積の平均値が10m/gの固体電解質と、比表面積の平均値が10m/gの負極活物質と、本発明所定の結着剤とを、上記の溶媒に添加する場合、負極合剤100質量部に対する各添加成分の添加量は、負極活物質は49.5〜99質量部が好ましく、59.5〜95質量部がより好ましい。固体電解質は1〜50質量部が好ましく、5〜40質量部がより好ましい。第一結着剤は0.4〜10質量部が好ましく、0.5〜9質量部がより好ましい。第二結着剤は0.1〜4質量部が好ましく、0.2〜4質量部がより好ましい。 As another example, a solid electrolyte of the average value of the specific surface area of 10 m 2 / g, a negative electrode active material of the mean value of the specific surface area of 10 m 2 / g, and the invention given binder to the solvent When adding, the addition amount of each additive component with respect to 100 parts by mass of the negative electrode mixture is preferably 49.5 to 99 parts by mass, more preferably 59.5 to 95 parts by mass for the negative electrode active material. The solid electrolyte is preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass. The first binder is preferably 0.4 to 10 parts by mass, and more preferably 0.5 to 9 parts by mass. The second binder is preferably 0.1 to 4 parts by mass, and more preferably 0.2 to 4 parts by mass.

[正極層および負極層作製工程]
正極層および負極層は、上記の所定の正極合剤又は負極合剤をそれぞれ集電体上に、好ましくは厚み250〜300μm、150〜200μmで塗布し、乾燥させて非極性溶媒を除去することにより作製することができる。集電体材料としては、シート状あるいはフィルム状の銅、ニッケル、チタン、アルミニウム等を用いることができる。本発明の第一結着剤および第二結着剤を含有する正極層や負極層は、結着力が強い結着剤を所定量含有するため、正極層と固体電解質層との剥離抑制に寄与する。
[Positive electrode layer and negative electrode layer manufacturing step]
For the positive electrode layer and the negative electrode layer, the above-described predetermined positive electrode mixture or negative electrode mixture is preferably applied on the current collector in a thickness of 250 to 300 μm and 150 to 200 μm, and dried to remove the nonpolar solvent. Can be produced. As the current collector material, sheet-like or film-like copper, nickel, titanium, aluminum or the like can be used. Since the positive electrode layer and the negative electrode layer containing the first binder and the second binder of the present invention contain a predetermined amount of a binder having a strong binding force, it contributes to suppression of peeling between the positive electrode layer and the solid electrolyte layer. To do.

正極合剤や負極合剤の集電体への塗布は、ダイコーター、ドクターブレード等を用いることができる。集電体上に塗布された正極合剤や負極合剤は、熱処理し、溶媒を除去する。式(1)で表される構成単位を有する第一結着剤を用いる場合、熱処理温度は、60〜150℃が好ましく、熱処理時間は15〜30分間が好ましい。式(2)で表される構成単位を有する第一結着剤を用いる場合、熱処理温度は、40〜120℃が好ましく、熱処理時間は10〜30分間が好ましい。熱処理後の正極合剤や負極合剤を真空乾燥させることにより非極性溶媒が除去され、本発明に用いる正極層や負極層を形成することができる。真空乾燥は、好ましくは40〜120℃、より好ましくは60〜100℃で行われる。乾燥後の正極層の厚みは150〜200μmが好ましい。負極層の厚みは100〜180μmが好ましい。   A die coater, a doctor blade, or the like can be used to apply the positive electrode mixture or the negative electrode mixture to the current collector. The positive electrode mixture and the negative electrode mixture applied on the current collector are heat-treated to remove the solvent. When the first binder having the structural unit represented by the formula (1) is used, the heat treatment temperature is preferably 60 to 150 ° C., and the heat treatment time is preferably 15 to 30 minutes. When using the 1st binder which has a structural unit represented by Formula (2), 40-120 degreeC is preferable for heat processing temperature, and 10-30 minutes are preferable for heat processing time. The non-polar solvent is removed by vacuum drying the positive electrode mixture and the negative electrode mixture after the heat treatment, and the positive electrode layer and the negative electrode layer used in the present invention can be formed. The vacuum drying is preferably performed at 40 to 120 ° C, more preferably 60 to 100 ° C. The thickness of the positive electrode layer after drying is preferably 150 to 200 μm. The thickness of the negative electrode layer is preferably 100 to 180 μm.

[固体電解質層形成工程]
本発明の固体電解質層は、固体電解質と第一結着剤と第二結着剤とを混合することにより作製することができる。硫化物固体電解質と第一結着剤と第二結着剤との混合は、固体電解質混合液を調製して行ってもよく、固体電解質粉末と各結着剤の粉末とを全固体電池のセル容器内の正極層と負極層との間に充填させて行ってもよい。固体電解質と第一結着剤と第二結着剤とを均質に混合させる観点からは、固体電解質混合液を調製して混合させることが好ましい。
[Solid electrolyte layer forming step]
The solid electrolyte layer of the present invention can be produced by mixing the solid electrolyte, the first binder, and the second binder. The mixing of the sulfide solid electrolyte, the first binder, and the second binder may be performed by preparing a solid electrolyte mixed solution. The solid electrolyte powder and the powder of each binder may be mixed in the all-solid battery. You may carry out by making it fill between the positive electrode layer and negative electrode layer in a cell container. From the viewpoint of homogeneously mixing the solid electrolyte, the first binder, and the second binder, it is preferable to prepare and mix the solid electrolyte mixture.

本発明の固体電解質混合液を調製する場合、固体電解質と本発明所定の第一結着剤と第二結着剤との混合は、溶媒中で撹拌することにより行われる。固体電解質としては、上記に説明した固体電解質が好ましく、硫化物固体電解質がより好ましい。硫化物固体電解質は、硫化ケイ素と硫化リンと硫化ホウ素とからなる群から選ばれる一つ以上の化合物と、硫化リチウムとを出発原料とし、前記化合物の合計添加量と硫化リチウムの添加量とのモル比を50:50〜30:70の範囲内として混合することにより合成することができる。混合法としては、MM法や溶液法を適用することができる。   When preparing the solid electrolyte mixed solution of the present invention, the solid electrolyte, the first binder and the second binder specified in the present invention are mixed by stirring in a solvent. As the solid electrolyte, the solid electrolyte described above is preferable, and a sulfide solid electrolyte is more preferable. The sulfide solid electrolyte is obtained by using, as a starting material, one or more compounds selected from the group consisting of silicon sulfide, phosphorus sulfide, and boron sulfide, and a total amount of the compounds and the amount of lithium sulfide added. It can synthesize | combine by mixing as molar ratio within the range of 50: 50-30: 70. As the mixing method, an MM method or a solution method can be applied.

固体電解質混合液の粘度は、1〜15Pa・sが好ましく、2〜12Pa・sがより好ましい。粘度の調節は、溶媒量の増加や増粘剤の添加により行うことできる。溶媒はキシレン、トルエン等非極性溶媒が好ましく用いられる。上記の好ましい粘度になるように添加されることで、本発明所定の第二結着剤は溶解し、固体電解質混合液内で、第二結着剤を均質に分散させることができる。第一結着剤は溶解せず、粒子状になって混合液内に分散する。   The viscosity of the solid electrolyte mixture is preferably 1 to 15 Pa · s, and more preferably 2 to 12 Pa · s. The viscosity can be adjusted by increasing the amount of solvent or adding a thickener. The solvent is preferably a nonpolar solvent such as xylene or toluene. By adding so that it may become said preferable viscosity, this invention predetermined | prescribed 2nd binder melt | dissolves and it can disperse | distribute a 2nd binder uniformly in a solid electrolyte liquid mixture. The first binder does not dissolve but forms particles and is dispersed in the mixed solution.

各添加成分の添加量は、用いられる固体電解質の比表面積に対応して適宜調節される。例えば、比表面積の平均値が2m/gの固体電解質と本発明所定の第一結着剤と第二結着剤とを、非極性溶媒に添加する場合、該溶媒に各添加成分を添加して得られる固体電解質混合液100質量部に対する各添加成分の添加量は、固体電解質は90〜90.9質量部が好ましく、95〜99.8質量部がより好ましい。第一結着剤は0.05〜8質量部が好ましく、0.1〜6質量部がより好ましい。第二結着剤は0.05〜4質量部が好ましく、0.1〜3質量部がより好ましい。 The amount of each additive component added is appropriately adjusted according to the specific surface area of the solid electrolyte used. For example, when a solid electrolyte having an average specific surface area of 2 m 2 / g, the first binder and the second binder specified in the present invention are added to a nonpolar solvent, each additive component is added to the solvent. The amount of each additive component added to 100 parts by mass of the solid electrolyte mixture obtained in this manner is preferably 90-90.9 parts by mass, more preferably 95-99.8 parts by mass for the solid electrolyte. The first binder is preferably 0.05 to 8 parts by mass, and more preferably 0.1 to 6 parts by mass. The second binder is preferably 0.05 to 4 parts by mass, and more preferably 0.1 to 3 parts by mass.

他の例として、比表面積の平均値が10m/gの固体電解質と本発明所定の結着剤とを、上記の溶媒に添加する場合、固体電解質混合液100質量部に対する各添加成分の添加量は、固体電解質は90〜99.5質量部が好ましく、92〜99.0質量部がより好ましい。第一結着剤は0.4〜9質量部が好ましく、1.0〜8質量部がより好ましい。第二結着剤は0.1〜6質量部が好ましく、0.5〜5質量部がより好ましい。 As another example, when a solid electrolyte having an average specific surface area of 10 m 2 / g and the binder of the present invention are added to the above solvent, addition of each additive component to 100 parts by mass of the solid electrolyte mixed solution The amount of the solid electrolyte is preferably 90 to 99.5 parts by mass, and more preferably 92 to 99.0 parts by mass. The first binder is preferably 0.4 to 9 parts by mass, and more preferably 1.0 to 8 parts by mass. The second binder is preferably 0.1 to 6 parts by mass, and more preferably 0.5 to 5 parts by mass.

得られた固体電解質混合液を、平坦な表面を備えるポリエチレンテレフタレート(PET)製の支持体にダイコーター等を用いて塗布する。その膜厚は、150〜200μmが好ましい。支持体に塗布された固体電解質混合液は、熱処理を行い溶媒を除去する。非極性溶媒を用いる場合、硫化物固体電解質と溶媒との反応を回避できるため、溶媒が完全に除去されるまでに起きる硫化物固体電解質のリチウムイオン伝導度の低下を抑制できる。熱処理温度は、60〜150℃が好ましく、熱処理時間は15〜30分間が好ましい。熱処理後の固体電解質混合液を真空乾燥させることで、本発明に用いる固体電解質層を得ることができる。真空乾燥は、好ましくは40〜120℃、より好ましくは60〜100℃で行われる。上記の固体電解質層は、支持体から剥離させて用いられる。   The obtained solid electrolyte mixture is applied to a support made of polyethylene terephthalate (PET) having a flat surface using a die coater or the like. The film thickness is preferably 150 to 200 μm. The solid electrolyte mixture applied to the support is subjected to a heat treatment to remove the solvent. When a nonpolar solvent is used, the reaction between the sulfide solid electrolyte and the solvent can be avoided, so that a decrease in lithium ion conductivity of the sulfide solid electrolyte that occurs until the solvent is completely removed can be suppressed. The heat treatment temperature is preferably 60 to 150 ° C., and the heat treatment time is preferably 15 to 30 minutes. The solid electrolyte layer used in the present invention can be obtained by vacuum drying the solid electrolyte mixture after the heat treatment. The vacuum drying is preferably performed at 40 to 120 ° C, more preferably 60 to 100 ° C. The solid electrolyte layer is used by being peeled from the support.

固体電解質と第一結着剤と第二結着剤とを溶媒を用いずに混合させる方法としては、固体電解質粉末と各結着剤の粉末とをボールミル等を用いて撹拌後加圧成形する方法がある。その場合、成型時の圧力条件は、0.1〜5ton/cmが好ましく、1〜4ton/cmがより好ましい。 As a method of mixing the solid electrolyte, the first binder, and the second binder without using a solvent, the solid electrolyte powder and each binder powder are agitated using a ball mill or the like and then pressure-molded. There is a way. In that case, the pressure conditions at the time of molding is preferably 0.1~5ton / cm 2, 1~4ton / cm 2 is more preferable.

得られた正極層と固体電解質層と負極層とを不活性雰囲気中で積層させ、加圧して一体化することにより、本発明の全固体二次電池を製造することができる。加圧条件は、0.5〜10ton/cmが好ましく、2〜6ton/cmがより好ましい。第一結着剤と第二結着剤とを含有する層においては、第一結着剤は非連続的に存在し、第二結着剤は連続的に存在する。加圧されることにより、各層の少なくともいずれかに含有される第一結着剤が層内で第一結着剤が融解する。これにより第一結着剤は、固体電解質、正極活物質、負極活物質等の粒子間の介在領域で強固な結着力を発揮する。これにより各層の界面の結着性が良好な本発明の全固体二次電池を製造することができる。該全固体二次電池は、充放電を繰り返しても層間剥離が少ない製品寿命が長い全固体二次電池である。 The obtained positive electrode layer, solid electrolyte layer, and negative electrode layer are laminated in an inert atmosphere, and are pressed and integrated to produce the all-solid-state secondary battery of the present invention. Pressurization condition is preferably 0.5~10ton / cm 2, 2~6ton / cm 2 is more preferable. In the layer containing the first binder and the second binder, the first binder is discontinuously present and the second binder is continuously present. By being pressurized, the first binder contained in at least one of the layers is melted in the layer. Accordingly, the first binder exhibits a strong binding force in the intervening region between the particles of the solid electrolyte, the positive electrode active material, the negative electrode active material, and the like. Thereby, the all-solid-state secondary battery of the present invention having good binding properties at the interface of each layer can be produced. The all-solid-state secondary battery is an all-solid-state secondary battery having a long product life with little delamination even after repeated charge and discharge.

[実施例1]
実施例1として正極層に第一結着剤と第二結着剤とを含有する全固体二次電池を作製した。実施例1の正極層の形成について説明する。正極活物質としてのLiNiCoAlO三元系粉末と、硫化物系固体電解質としてのLiS−P(モル%比80:20)非晶質粉末と、正極層導電性物質(導電助剤)としての気相成長炭素繊維粉末とを60:35:5の質量%比で秤量し、自転公転ミキサを用いて混合した。
[Example 1]
As Example 1, an all-solid secondary battery containing a first binder and a second binder in the positive electrode layer was produced. The formation of the positive electrode layer of Example 1 will be described. LiNiCoAlO 2 ternary powder as the positive electrode active material, Li 2 S—P 2 S 5 (molar% ratio 80:20) amorphous powder as the sulfide solid electrolyte, and positive electrode layer conductive material (conductivity aid) The vapor-grown carbon fiber powder as the agent) was weighed in a mass% ratio of 60: 35: 5 and mixed using a rotating and rotating mixer.

上記の混合粉に、第二結着剤としてのSBRを溶解させた脱水キシレン溶液を添加して1次混合液を調製した。1次混合液は、SBRが混合粉の総質量に対して1.0質量%となるようにした。得られた1次混合液に、第一結着剤としての平均粒子径3μmのPVdFを添加し、さらに脱水キシレンを適量添加して粘度を調節して2次混合液を調製した。PVdFの含有量は、混合粉の総質量に対して5.0質量%となるようにした。   A dehydrated xylene solution in which SBR as a second binder was dissolved was added to the above mixed powder to prepare a primary mixed solution. The primary mixed solution was such that SBR was 1.0 mass% with respect to the total mass of the mixed powder. To the obtained primary mixed solution, PVdF having an average particle size of 3 μm as a first binder was added, and an appropriate amount of dehydrated xylene was added to adjust the viscosity to prepare a secondary mixed solution. The content of PVdF was 5.0% by mass with respect to the total mass of the mixed powder.

この2次混合液にさらに、直径5mmのジルコニアボールを、空間、混合粉、ジルコニアボールがそれぞれ混練容器の全容積に対して1/3ずつを占めるようにして投入して混練し、混合粉の分散性を向上させたものを3次混合液とした。3次混合液を自転公転ミキサに投入し、3000rpmで3分撹拌することで、正極合剤を調製した。   Further, zirconia balls having a diameter of 5 mm are added to this secondary mixed solution so that the space, mixed powder, and zirconia balls each occupy 1/3 of the total volume of the kneading vessel, and are kneaded. What improved the dispersibility was made into the tertiary liquid mixture. The tertiary mixture was put into a rotation and revolution mixer and stirred at 3000 rpm for 3 minutes to prepare a positive electrode mixture.

正極集電体として厚さ15μmのアルミ箔集電体を用意し、卓上スクリーン印刷機に正極集電体を載置した。正極集電体上に150μmのメタルマスクを用いて正極合剤を塗工した。正極合剤を塗工した正極集電体を120℃のホットプレートで30分乾燥させた。さらに、80℃で12時間真空乾燥させ、正極集電体上に正極層を形成した。乾燥後の正極集電体及び正極層の総厚さは165μm前後であった。   An aluminum foil current collector having a thickness of 15 μm was prepared as a positive electrode current collector, and the positive electrode current collector was placed on a desktop screen printer. The positive electrode mixture was applied onto the positive electrode current collector using a 150 μm metal mask. The positive electrode current collector coated with the positive electrode mixture was dried on a hot plate at 120 ° C. for 30 minutes. Furthermore, it was vacuum-dried at 80 ° C. for 12 hours to form a positive electrode layer on the positive electrode current collector. The total thickness of the positive electrode current collector and the positive electrode layer after drying was around 165 μm.

上記の正極集電体と正極層とからなるシートを、ロールギャップ20μmのロールプレス機を用いて圧延し、正極集電体と正極層とからなる正極構造体を得た。乾燥後の正極構造体の厚みは120μm前後であった。   The sheet comprising the positive electrode current collector and the positive electrode layer was rolled using a roll press machine having a roll gap of 20 μm to obtain a positive electrode structure comprising the positive electrode current collector and the positive electrode layer. The thickness of the positive electrode structure after drying was around 120 μm.

上記の正極構造体を用いて、不活性ガス中で、内径1.3cmの円筒形の成型治具内で全固体二次電池を作製した。LiS−P(モル%比80:20)非晶質粉末100mgを、成形冶具中に挿入して、2ton/cmでプレス成形し、固体電解質層を形成した。上記の正極構造体を直径1.3cmの円形に切り取り、成型治具内の固体電解質層上に載置し、2ton/cmでプレス成形して固体電解質層と正極合剤層とを一体化させた。 Using the above positive electrode structure, an all-solid secondary battery was produced in an inert gas in a cylindrical molding jig having an inner diameter of 1.3 cm. 100 mg of Li 2 S—P 2 S 5 (molar ratio 80:20) amorphous powder was inserted into a forming jig and press-molded at 2 ton / cm 2 to form a solid electrolyte layer. The positive electrode structure is cut into a circle having a diameter of 1.3 cm, placed on a solid electrolyte layer in a molding jig, and press-molded at 2 ton / cm 2 to integrate the solid electrolyte layer and the positive electrode mixture layer. It was.

次に、成型治具内の固体電解質層の正極層形成面と反対側の面に、80℃で24時間真空乾燥させた黒鉛粉末20.0mgと負極集電体とを挿入した。挿入後、4ton/cmでプレス成形して固体電解質層と負極層と負極集電体とを一体化させた。これにより、固体電解質層が正極層と負極層とで挟持された全固体二次電池のセルを得た。 Next, 20.0 mg of graphite powder vacuum-dried at 80 ° C. for 24 hours and a negative electrode current collector were inserted into the surface of the solid electrolyte layer on the side opposite to the surface on which the positive electrode layer was formed. After the insertion, the solid electrolyte layer, the negative electrode layer, and the negative electrode current collector were integrated by press molding at 4 ton / cm 2 . Thereby, the cell of the all-solid-state secondary battery by which the solid electrolyte layer was clamped by the positive electrode layer and the negative electrode layer was obtained.

[実施例2−5]
実施例1の第二結着剤と溶媒とを表1の内容に変えた他は実施例1と同様にして、実施例2−5を得た。
[Example 2-5]
Example 2-5 was obtained in the same manner as in Example 1 except that the second binder and the solvent in Example 1 were changed to those shown in Table 1.

[実施例6]
実施例6においては、負極層に結着剤としてPVdFを含有させた全固体二次電池を作製した。まず負極合剤を調製するため、負極活物質として80℃で24時間真空乾燥させた黒鉛粉末と、硫化物系固体電解質としてのLiS−P(モル%比80:20)非晶質粉末と、負極層導電性物質(導電助剤)としての気相成長炭素繊維粉末とを60:35:5の質量%比で秤量し、自転公転ミキサを用いて混合した。
[Example 6]
In Example 6, an all-solid secondary battery in which PVdF was contained as a binder in the negative electrode layer was produced. First, in order to prepare a negative electrode mixture, graphite powder vacuum-dried at 80 ° C. for 24 hours as a negative electrode active material, and Li 2 S—P 2 S 5 (molar ratio 80:20) as a sulfide-based solid electrolyte The crystalline powder and the vapor-grown carbon fiber powder as the negative electrode layer conductive material (conducting aid) were weighed in a mass% ratio of 60: 35: 5 and mixed using a rotation and revolution mixer.

上記の混合粉に、第二結着剤としてのSBRを溶解させた脱水キシレン溶液を添加して1次混合液を調製した。1次混合液は、SBRが混合粉の総質量に対して3.0質量%となるようにした。得られた1次混合液に、第一結着剤としての平均粒子径3μmのPVdFを添加し、さらに脱水キシレンを適量添加して粘度を調節して2次混合液を調製した。PVdFの含有量は、混合粉の総質量に対して2.0質量%となるようにした。   A dehydrated xylene solution in which SBR as a second binder was dissolved was added to the above mixed powder to prepare a primary mixed solution. The primary mixed solution was such that SBR was 3.0% by mass with respect to the total mass of the mixed powder. To the obtained primary mixed solution, PVdF having an average particle size of 3 μm as a first binder was added, and an appropriate amount of dehydrated xylene was added to adjust the viscosity to prepare a secondary mixed solution. The content of PVdF was 2.0% by mass with respect to the total mass of the mixed powder.

この2次混合液にさらに、直径5mmのジルコニアボールを、空間、混合粉、ジルコニアボールがそれぞれ混練容器の全容積に対して1/3ずつを占めるようにして投入して混練し、混合粉の分散性を向上させたものを3次混合液とした。3次混合液を自転公転ミキサに投入し、3000rpmで3分撹拌することで、負極合剤を調製した。   Further, zirconia balls having a diameter of 5 mm are added to this secondary mixed solution so that the space, mixed powder, and zirconia balls each occupy 1/3 of the total volume of the kneading vessel, and are kneaded. What improved the dispersibility was made into the tertiary liquid mixture. The tertiary mixture was put into a rotation and revolution mixer and stirred at 3000 rpm for 3 minutes to prepare a negative electrode mixture.

負極集電体として厚さ15μmの銅箔集電体を用意し、卓上スクリーン印刷機に負極集電体を載置した。負極集電体上に150μmのメタルマスクを用いて負極合剤を塗工した。負極合剤を塗工した負極集電体を120℃のホットプレートで30分乾燥させた。さらに、80℃で12時間真空乾燥させ、負極集電体上に負極層を形成した。乾燥後の負極集電体及び負極層の総厚さは165μm前後であった。   A copper foil current collector having a thickness of 15 μm was prepared as a negative electrode current collector, and the negative electrode current collector was placed on a desktop screen printer. A negative electrode mixture was applied onto the negative electrode current collector using a 150 μm metal mask. The negative electrode current collector coated with the negative electrode mixture was dried on a hot plate at 120 ° C. for 30 minutes. Furthermore, it was vacuum-dried at 80 ° C. for 12 hours to form a negative electrode layer on the negative electrode current collector. The total thickness of the negative electrode current collector and the negative electrode layer after drying was around 165 μm.

上記の負極集電体と負極層とからなるシートを、ロールギャップ20μmのロールプレス機を用いて圧延し、負極集電体と負極層とからなる負極構造体を得た。乾燥後の負極構造体の厚みは120μm前後であった。   The sheet composed of the negative electrode current collector and the negative electrode layer was rolled using a roll press machine having a roll gap of 20 μm to obtain a negative electrode structure composed of the negative electrode current collector and the negative electrode layer. The thickness of the negative electrode structure after drying was around 120 μm.

正極合剤は、下記のように調製した。正極活物質としてのLiNiCoAlO三元系粉末と、硫化物系固体電解質としてのLiS−P(モル%比80:20)非晶質粉末と、正極層導電性物質(導電助剤)としての気相成長炭素繊維粉末とを60:35:5の質量%比で秤量し、さらに第二結着剤を添加して自転公転ミキサを用いて混合した。 The positive electrode mixture was prepared as follows. LiNiCoAlO 2 ternary powder as the positive electrode active material, Li 2 S—P 2 S 5 (molar% ratio 80:20) amorphous powder as the sulfide solid electrolyte, and positive electrode layer conductive material (conductivity aid) The vapor-grown carbon fiber powder as the agent) was weighed in a mass% ratio of 60: 35: 5, and the second binder was further added and mixed using a rotation and revolution mixer.

上記の混合粉に、脱水キシレン溶液を添加して1次混合液を調製した。得られた1次混合液に脱水キシレンを適量添加して粘度を調節し、2次混合液を調製した。この2次混合液にさらに、直径5mmのジルコニアボールを、空間、混合粉、ジルコニアボールがそれぞれ混練容器の全容積に対して1/3ずつを占めるようにして投入して混練し、混合粉の分散性を向上させたものを3次混合液とした。3次混合液を自転公転ミキサに投入し、3000rpmで3分撹拌することで、正極合剤を調製した。   A dehydrated xylene solution was added to the above mixed powder to prepare a primary mixed solution. An appropriate amount of dehydrated xylene was added to the obtained primary mixed liquid to adjust the viscosity, thereby preparing a secondary mixed liquid. Further, zirconia balls having a diameter of 5 mm are added to this secondary mixed solution so that the space, mixed powder, and zirconia balls each occupy 1/3 of the total volume of the kneading vessel, and are kneaded. What improved the dispersibility was made into the tertiary liquid mixture. The tertiary mixture was put into a rotation and revolution mixer and stirred at 3000 rpm for 3 minutes to prepare a positive electrode mixture.

正極集電体として厚さ15μmのアルミ箔集電体を用意し、卓上スクリーン印刷機に正極集電体を載置した。正極集電体上に150μmのメタルマスクを用いて正極合剤を塗工した。正極合剤を塗工した正極集電体を120℃のホットプレートで30分乾燥させた。さらに、80℃で12時間真空乾燥させ、正極集電体上に正極層を形成した。乾燥後の正極集電体及び正極層の総厚さは165μm前後であった。   An aluminum foil current collector having a thickness of 15 μm was prepared as a positive electrode current collector, and the positive electrode current collector was placed on a desktop screen printer. The positive electrode mixture was applied onto the positive electrode current collector using a 150 μm metal mask. The positive electrode current collector coated with the positive electrode mixture was dried on a hot plate at 120 ° C. for 30 minutes. Furthermore, it was vacuum-dried at 80 ° C. for 12 hours to form a positive electrode layer on the positive electrode current collector. The total thickness of the positive electrode current collector and the positive electrode layer after drying was around 165 μm.

上記の正極集電体と正極層とからなるシートを、ロールギャップ10μmのロールプレス機を用いて圧延し、正極集電体と正極層とからなる正極構造体を得た。乾燥後の正極構造体の厚みは120μm前後であった。   The sheet comprising the positive electrode current collector and the positive electrode layer was rolled using a roll press machine having a roll gap of 10 μm to obtain a positive electrode structure comprising the positive electrode current collector and the positive electrode layer. The thickness of the positive electrode structure after drying was around 120 μm.

上記の負極構造体と正極構造体を用いて、不活性ガス中で、内径1.3cmの円筒形の成型治具内で全固体二次電池を作製した。LiS−P(モル%比80:20)非晶質粉末100mgを、成形冶具中に挿入して、2ton/cmでプレス成形し、固体電解質層を形成した。上記の負極構造体と正極構造体を直径1.3cmの円形に切り取り、成型治具内の固体電解質層の両面にそれぞれ載置し、2ton/cmでプレス成形して、負極層と固体電解質層と正極合剤層とを一体化させた。これにより、固体電解質層が正極層と負極層とで挟持された全固体二次電池のセルを得た。得られた固体電解質二次電池を実施例6とした。 Using the negative electrode structure and the positive electrode structure described above, an all-solid secondary battery was produced in an inert gas in a cylindrical molding jig having an inner diameter of 1.3 cm. 100 mg of Li 2 S—P 2 S 5 (molar ratio 80:20) amorphous powder was inserted into a forming jig and press-molded at 2 ton / cm 2 to form a solid electrolyte layer. The negative electrode structure and the positive electrode structure are cut into a circle having a diameter of 1.3 cm, placed on both sides of the solid electrolyte layer in the molding jig, and press-molded at 2 ton / cm 2. The negative electrode layer and the solid electrolyte layer And the positive electrode mixture layer were integrated. Thereby, the cell of the all-solid-state secondary battery by which the solid electrolyte layer was clamped by the positive electrode layer and the negative electrode layer was obtained. The obtained solid electrolyte secondary battery was taken as Example 6.

[実施例7]
実施例7においては、固体電解質層に結着剤としてPVdFを含有させた全固体二次電池を作製した。まず固体電解質混合溶液を調製するため、硫化物系固体電解質としてのLiS−P(モル%比80:20)非晶質粉末に第二結着剤としてのSBRを溶解させた脱水キシレン溶液を添加して1次混合液を調製した。該1次混合液に、第一結着剤としてPVdFを添加し、さらに脱水キシレン溶液を添加して粘度を調製し、2次混合液を調製した。SBRは固体電解質粉末に対し、2質量%となるように添加した。PVdFは固体電解質粉末に対し、5質量%となるように添加した。
[Example 7]
In Example 7, an all-solid secondary battery in which PVdF was contained as a binder in the solid electrolyte layer was produced. First, in order to prepare a solid electrolyte mixed solution, SBR as a second binder was dissolved in Li 2 S—P 2 S 5 (molar ratio 80:20) amorphous powder as a sulfide-based solid electrolyte. A dehydrated xylene solution was added to prepare a primary mixture. To the primary mixture, PVdF was added as a first binder, and a dehydrated xylene solution was further added to adjust the viscosity, thereby preparing a secondary mixture. SBR was added to 2% by mass with respect to the solid electrolyte powder. PVdF was added to 5% by mass with respect to the solid electrolyte powder.

この2次混合液にさらに、直径5mmのジルコニアボールを、空間、固体電解質、ジルコニアボールがそれぞれ混練容器の全容積に対して1/3ずつを占めるようにして投入して混練し、固体電解質の分散性を向上させたものを3次混合液とした。3次混合液を自転公転ミキサに投入し、3000rpmで3分撹拌することで、固体電解質混合液を調製した。   Further, zirconia balls having a diameter of 5 mm are added to this secondary mixed solution so that the space, the solid electrolyte, and the zirconia balls each occupy 1/3 of the total volume of the kneading vessel, and are kneaded. What improved the dispersibility was made into the tertiary liquid mixture. The tertiary mixed solution was put into a rotation and revolution mixer and stirred at 3000 rpm for 3 minutes to prepare a solid electrolyte mixed solution.

支持体として厚さ15μmのPETシートを用意し、卓上スクリーン印刷機に支持体を載置した。支持体上に150μmのメタルマスクを用いて固体電解質混合液を塗工した。固体電解質混合液を塗工した支持体を120℃のホットプレートで30分乾燥させた。さらに、80℃で12時間真空乾燥させ、支持体上に固体電解質層を形成した。   A PET sheet having a thickness of 15 μm was prepared as a support, and the support was placed on a desktop screen printer. The solid electrolyte mixture was applied onto the support using a 150 μm metal mask. The support coated with the solid electrolyte mixture was dried on a hot plate at 120 ° C. for 30 minutes. Furthermore, it was vacuum-dried at 80 ° C. for 12 hours to form a solid electrolyte layer on the support.

上記の支持体と固体電解質層とからなるシートを、ロールギャップ10μmのロールプレス機を用いて圧延したのち、固体電解質層を支持体から剥離させた。乾燥後の固体電解質層の厚みは120μm前後であった。   The sheet comprising the above support and the solid electrolyte layer was rolled using a roll press with a roll gap of 10 μm, and then the solid electrolyte layer was peeled from the support. The thickness of the solid electrolyte layer after drying was around 120 μm.

負極合剤は、下記のように調製した。負極活物質として黒鉛粉末と、80℃で24時間真空乾燥させた負極層導電性物質(導電助剤)としての気相成長炭素繊維粉末とを90:10の質量%比で秤量し、自転公転ミキサを用いて混合した。   The negative electrode mixture was prepared as follows. Graphite powder as a negative electrode active material and vapor grown carbon fiber powder as a negative electrode layer conductive material (conductive aid) vacuum-dried at 80 ° C. for 24 hours are weighed at a mass ratio of 90:10 and rotated and rotated. Mix using a mixer.

上記の混合粉に、脱水NMP溶液を添加して1次混合液を調製した。得られた1次混合液に脱水NMPを適量添加して粘度を調節し、2次混合液を調製した。この2次混合液にさらに、直径5mmのジルコニアボールを、空間、混合粉、ジルコニアボールがそれぞれ混練容器の全容積に対して1/3ずつを占めるようにして投入して混練し、混合粉の分散性を向上させたものを3次混合液とした。3次混合液を自転公転ミキサに投入し、3000rpmで3分撹拌することで、負極合剤を調製した。   A dehydrated NMP solution was added to the above mixed powder to prepare a primary mixed solution. An appropriate amount of dehydrated NMP was added to the obtained primary mixed solution to adjust the viscosity, thereby preparing a secondary mixed solution. Further, zirconia balls having a diameter of 5 mm are added to this secondary mixed solution so that the space, mixed powder, and zirconia balls each occupy 1/3 of the total volume of the kneading container, and are kneaded. What improved the dispersibility was made into the tertiary liquid mixture. The tertiary mixture was put into a rotation and revolution mixer and stirred at 3000 rpm for 3 minutes to prepare a negative electrode mixture.

負極集電体として厚さ15μmの銅箔集電体を用意し、卓上スクリーン印刷機に負極集電体を載置した。負極集電体上に150μmのメタルマスクを用いて負極合剤を塗工した。負極合剤を塗工した負極集電体を120℃のホットプレートで30分乾燥させた。さらに、80℃で12時間真空乾燥させ、負極集電体上に負極層を形成した。乾燥後の負極集電体及び負極層の総厚さは165μm前後であった。   A copper foil current collector having a thickness of 15 μm was prepared as a negative electrode current collector, and the negative electrode current collector was placed on a desktop screen printer. A negative electrode mixture was applied onto the negative electrode current collector using a 150 μm metal mask. The negative electrode current collector coated with the negative electrode mixture was dried on a hot plate at 120 ° C. for 30 minutes. Furthermore, it was vacuum-dried at 80 ° C. for 12 hours to form a negative electrode layer on the negative electrode current collector. The total thickness of the negative electrode current collector and the negative electrode layer after drying was around 165 μm.

上記の負極集電体と負極層とからなるシートを、ロールギャップ20μmのロールプレス機を用いて圧延し、負極集電体と負極層とからなる負極構造体を得た。乾燥後の負極構造体の厚みは120μm前後であった。   The sheet composed of the negative electrode current collector and the negative electrode layer was rolled using a roll press machine having a roll gap of 20 μm to obtain a negative electrode structure composed of the negative electrode current collector and the negative electrode layer. The thickness of the negative electrode structure after drying was around 120 μm.

上記の負極構造体と固体電解質層を用いて、不活性ガス中で、内径1.3cmの円筒形の成型治具内で全固体二次電池を作製した。成型治具内に、負極構造体と固体電解質膜を載置して、2ton/cmでプレス成形し、負極構造体と固体電解質膜を一体化させ、負極層と固体電解質層を形成した。続いて固体電解質層の負極層形成面と反対側の面に、正極活物質としてのLiNiCoAlO三元系粉末と、硫化物系固体電解質としてのLiS−P(モル%比80:20)非晶質粉末と、正極層導電性物質(導電助剤)としての気相成長炭素繊維粉末とを60:35:5の質量%比で秤量して混合した粉末20mgと正極集電体とを挿入した。挿入後、4ton/cmでプレス成形して正極集電体と正極層と固体電解質層と負極層と負極集電体とを一体化させた。これにより、固体電解質層が正極層と負極層とで挟持された全固体二次電池のセルを得た。得られた固体電解質二次電池を実施例7とした。 Using the negative electrode structure and the solid electrolyte layer, an all-solid secondary battery was produced in an inert gas in a cylindrical molding jig having an inner diameter of 1.3 cm. The negative electrode structure and the solid electrolyte membrane were placed in a molding jig and press-molded at 2 ton / cm 2 to integrate the negative electrode structure and the solid electrolyte membrane, thereby forming a negative electrode layer and a solid electrolyte layer. Subsequently, on the surface of the solid electrolyte layer opposite to the negative electrode layer forming surface, LiNiCoAlO 2 ternary powder as the positive electrode active material and Li 2 S—P 2 S 5 as the sulfide solid electrolyte (molar ratio 80 : 20) 20 mg powder mixed with amorphous powder and vapor-grown carbon fiber powder as positive electrode conductive material (conducting aid) with a mass ratio of 60: 35: 5 and positive electrode current collector Inserted with the body. After the insertion, the positive electrode current collector, the positive electrode layer, the solid electrolyte layer, the negative electrode layer, and the negative electrode current collector were integrated by press molding at 4 ton / cm 2 . Thereby, the cell of the all-solid-state secondary battery by which the solid electrolyte layer was clamped by the positive electrode layer and the negative electrode layer was obtained. The obtained solid electrolyte secondary battery was taken as Example 7.

[実施例8]
実施例8においては、正極活物質としてのLiNiCoAlO三元系粉末と、硫化物系固体電解質としてのLiS−P(モル%比80:20)非晶質粉末と、正極層導電性物質(導電助剤)としての気相成長炭素繊維粉末とを60:35:5の質量%比で秤量し、自転公転ミキサを用いて混合した。
[Example 8]
In Example 8, LiNiCoAlO 2 ternary powder as a positive electrode active material, Li 2 S—P 2 S 5 (molar ratio 80:20) amorphous powder as a sulfide solid electrolyte, and positive electrode layer Vapor-grown carbon fiber powder as a conductive substance (conductive aid) was weighed at a mass% ratio of 60: 35: 5 and mixed using a rotation and revolution mixer.

上記の混合粉に、第二結着剤としてのSBRを溶解させた脱水キシレン溶液を添加して1次混合液を調製した。1次混合液は、SBRが混合粉の総質量に対して1.0質量%となるようにした。得られた1次混合液に、第一結着剤としての平均粒子径4μmのPVAを添加し、さらに脱水キシレンを適量添加して粘度を調節して2次混合液を調製した。PVAの含有量は、混合粉の総質量に対して7.0質量%となるようにした。   A dehydrated xylene solution in which SBR as a second binder was dissolved was added to the above mixed powder to prepare a primary mixed solution. The primary mixed solution was such that SBR was 1.0 mass% with respect to the total mass of the mixed powder. To the obtained primary mixed solution, PVA having an average particle diameter of 4 μm as a first binder was added, and an appropriate amount of dehydrated xylene was added to adjust the viscosity to prepare a secondary mixed solution. The content of PVA was 7.0% by mass with respect to the total mass of the mixed powder.

この2次混合液にさらに、直径5mmのジルコニアボールを、空間、混合粉、ジルコニアボールがそれぞれ混練容器の全容積に対して1/3ずつを占めるようにして投入して混練し、混合粉の分散性を向上させたものを3次混合液とした。3次混合液を自転公転ミキサに投入し、3000rpmで3分撹拌することで、正極合剤を調製した。   Further, zirconia balls having a diameter of 5 mm are added to this secondary mixed solution so that the space, mixed powder, and zirconia balls each occupy 1/3 of the total volume of the kneading container, and are kneaded. What improved the dispersibility was made into the tertiary liquid mixture. The tertiary mixture was put into a rotation and revolution mixer and stirred at 3000 rpm for 3 minutes to prepare a positive electrode mixture.

正極集電体として厚さ15μmのアルミ箔集電体を用意し、卓上スクリーン印刷機に正極集電体を載置した。正極集電体上に150μmのメタルマスクを用いて正極合剤を塗工した。正極合剤を塗工した正極集電体を120℃のホットプレートで30分乾燥させた。さらに、80℃で12時間真空乾燥させ、正極集電体上に正極層を形成した。乾燥後の正極集電体及び正極層の総厚さは150μm前後であった。   An aluminum foil current collector having a thickness of 15 μm was prepared as a positive electrode current collector, and the positive electrode current collector was placed on a desktop screen printer. The positive electrode mixture was applied onto the positive electrode current collector using a 150 μm metal mask. The positive electrode current collector coated with the positive electrode mixture was dried on a hot plate at 120 ° C. for 30 minutes. Furthermore, it was vacuum-dried at 80 ° C. for 12 hours to form a positive electrode layer on the positive electrode current collector. The total thickness of the positive electrode current collector and the positive electrode layer after drying was around 150 μm.

上記の正極集電体と正極層とからなるシートを、ロールギャップ20μmのロールプレス機を用いて圧延し、正極集電体と正極層とからなる正極構造体を得た。乾燥後の正極構造体の厚みは110μm前後であった。   The sheet comprising the positive electrode current collector and the positive electrode layer was rolled using a roll press machine having a roll gap of 20 μm to obtain a positive electrode structure comprising the positive electrode current collector and the positive electrode layer. The thickness of the positive electrode structure after drying was around 110 μm.

上記の正極構造体を用いて、不活性ガス中で、内径1.3cmの円筒形の成型治具内で全固体二次電池を作製した。LiS−P(モル%比80:20)非晶質粉末100mgを、成形冶具中に挿入して、2ton/cmでプレス成形し、固体電解質層を形成した。上記の正極構造体を直径1.3cmの円形に切り取り、成型治具内の固体電解質層上に載置し、2ton/cmでプレス成形して固体電解質層と正極合剤層とを一体化させた。 Using the above positive electrode structure, an all-solid secondary battery was produced in an inert gas in a cylindrical molding jig having an inner diameter of 1.3 cm. 100 mg of Li 2 S—P 2 S 5 (molar ratio 80:20) amorphous powder was inserted into a forming jig and press-molded at 2 ton / cm 2 to form a solid electrolyte layer. The positive electrode structure is cut into a circle having a diameter of 1.3 cm, placed on a solid electrolyte layer in a molding jig, and press-molded at 2 ton / cm 2 to integrate the solid electrolyte layer and the positive electrode mixture layer. It was.

次に、成型治具内の固体電解質層の正極層形成面と反対側の面に80℃で24時間真空乾燥させた黒鉛粉末20.0mgと負極集電体とを挿入した。挿入後、4ton/cmでプレス成形して固体電解質層と負極層と負極集電体とを一体化させた。これにより、固体電解質層が正極層と負極層とで挟持された全固体二次電池のセルを得た。 Next, 20.0 mg of graphite powder vacuum-dried at 80 ° C. for 24 hours and a negative electrode current collector were inserted into the surface of the solid electrolyte layer opposite to the surface on which the positive electrode layer was formed in the molding jig. After the insertion, the solid electrolyte layer, the negative electrode layer, and the negative electrode current collector were integrated by press molding at 4 ton / cm 2 . Thereby, the cell of the all-solid-state secondary battery by which the solid electrolyte layer was clamped by the positive electrode layer and the negative electrode layer was obtained.

[実施例9−10]
実施例8の第二結着剤をSBRからSBSに変えた他は実施例8と同様にして実施例9を得た。また、実施例8の第二結着剤をSBRからNBRに変えた他は、実施例8と同様にして、実施例9および実施例10を得た。
[Example 9-10]
Example 9 was obtained in the same manner as in Example 8, except that the second binder of Example 8 was changed from SBR to SBS. Further, Example 9 and Example 10 were obtained in the same manner as Example 8 except that the second binder of Example 8 was changed from SBR to NBR.

[比較例1−5]
第一結着剤を添加せず、第二結着剤と正極合剤の溶媒とを表1に示す成分に変えた他は実施例1と同様にして正極層を作製し、比較例1の全固体電池を作製した。また第一結着剤を添加せず、第二結着剤と負極合剤の溶媒とを表1に示す成分に変えた他は実施例1と同様にして負極層を作製し、比較例2の全固体電池を作製した。
[Comparative Example 1-5]
A positive electrode layer was prepared in the same manner as in Example 1 except that the first binder was not added and the second binder and the positive electrode mixture solvent were changed to the components shown in Table 1. An all-solid battery was produced. Further, a negative electrode layer was produced in the same manner as in Example 1 except that the first binder was not added and the second binder and the solvent of the negative electrode mixture were changed to the components shown in Table 1. Comparative Example 2 An all solid state battery was produced.

第二結着剤を添加せず、第一結着剤と正極合剤の溶媒とを表1に示す成分に変えた他は実施例1と同様にして比較例3の全固体電池の作製を試みた。しかし比較例3および比較例4においては、正極合剤の粘性が不足し、正極層を形成することができなかった。また第二結着剤を添加せず、第一結着剤と正極合剤の溶媒を表1の内容に変えた他は実施例1と同様にして、比較例5の全固体電池の作製を試みた。比較例5においては、硫化物固体電解質とPVdFとが反応してゲル化し、正極層を形成することができなかった。   The all-solid battery of Comparative Example 3 was prepared in the same manner as in Example 1 except that the second binder was not added and the solvent of the first binder and the positive electrode mixture was changed to the components shown in Table 1. Tried. However, in Comparative Example 3 and Comparative Example 4, the viscosity of the positive electrode mixture was insufficient, and the positive electrode layer could not be formed. The all-solid-state battery of Comparative Example 5 was produced in the same manner as in Example 1 except that the second binder was not added and the solvent of the first binder and the positive electrode mixture was changed to the contents shown in Table 1. Tried. In Comparative Example 5, the sulfide solid electrolyte and PVdF reacted to gel, and a positive electrode layer could not be formed.

実施例1−10および比較例1、2について室温で0.05Cの定電流充放電サイクル試験を実施し、1サイクル目と、50サイクル目との放電容量を測定した。
[サイクル試験]
室温で0.05Cの定電流充放電サイクル試験を実施した。50サイクル後に単セルを解体し、正極層と集電体の結着を確認したところ、実施例1-10について、剥離は確認されなかった。また、正極層、負極層、固体電解質層に含有される粒子の結着も保たれていた。これに対し、比較例1と比較例2とは、電極と集電箔とが剥離している部分が確認された。
About Example 1-10 and Comparative Examples 1 and 2, the constant current charging / discharging cycle test of 0.05C was implemented at room temperature, and the discharge capacity of 1st cycle and 50th cycle was measured.
[Cycle test]
A constant current charge / discharge cycle test of 0.05 C was performed at room temperature. When the single cell was disassembled after 50 cycles and the binding between the positive electrode layer and the current collector was confirmed, no peeling was confirmed for Example 1-10. Further, the binding of particles contained in the positive electrode layer, the negative electrode layer, and the solid electrolyte layer was also maintained. On the other hand, the comparative example 1 and the comparative example 2 confirmed the part which the electrode and current collection foil have peeled.

また、1サイクル目の放電容量を100%として50サイクル目の放電容量を比較し、50サイクル後の放電容量の維持率を求めた。実施結果を表1に示す。   Further, the discharge capacity at the first cycle was set to 100%, the discharge capacity at the 50th cycle was compared, and the retention rate of the discharge capacity after 50 cycles was determined. The results are shown in Table 1.

100 全固体二次電池
200 正極層
201 正極活物質
202 第一結着剤
203 第二結着剤
300 固体電解質層
301 固体電解質
400 負極層
501、502 集電体
100 all-solid secondary battery 200 positive electrode layer 201 positive electrode active material 202 first binder 203 second binder 300 solid electrolyte layer 301 solid electrolyte 400 negative electrode layers 501 and 502 current collector

Claims (10)

正極層と、負極層と、固体電解質層とのいずれか一つ以上に、非連続的に存在する非極性溶媒不溶性の第一結着剤と、連続的に存在する非極性溶媒可溶性の第二結着剤とを含み、第一結着剤と第二結着剤とのSP値が異なり、
第二結着剤が、炭化水素系高分子である全固体二次電池。
Any one or more of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer is non-continuously present in a non-polar solvent-insoluble first binder and continuously present in a non-polar solvent-soluble second binder. and a binder, Ri SP value Do different between the first binder and the second binder,
Second binder, all-solid secondary battery Ru Ah with hydrocarbon-based polymer.
正極層と負極層と固体電解質層とのいずれか一つ以上に含まれる固体電解質が、硫化物固体電解質である請求項1に記載の全固体二次電池。   The all-solid-state secondary battery according to claim 1, wherein the solid electrolyte contained in any one or more of the positive electrode layer, the negative electrode layer, and the solid electrolyte layer is a sulfide solid electrolyte. 第一結着剤のSP値が20〔MPa1/2〕以上30〔MPa1/2〕以下である請求項1または請求項2に記載の全固体二次電池。 The all-solid-state secondary battery according to claim 1, wherein the SP value of the first binder is 20 [MPa 1/2 ] or more and 30 [MPa 1/2 ] or less. 第二結着剤のSP値が5〔MPa1/2〕以上20〔MPa1/2〕未満である請求項1ないし請求項3のいずれかに記載の全固体二次電池。 The all-solid-state secondary battery according to any one of claims 1 to 3, wherein the SP value of the second binder is 5 [MPa 1/2 ] or more and less than 20 [MPa 1/2 ]. 第一結着剤の平均粒子径が、0.01〜10μmである請求項1ないし請求項4のいずれかに記載の全固体二次電池。   The all-solid-state secondary battery according to any one of claims 1 to 4, wherein the average particle diameter of the first binder is 0.01 to 10 µm. 第一結着剤が、下記式(1)で表される構成単位を有する化合物である請求項1ないし請求項5のいずれかに記載の全固体二次電池。
The all-solid-state secondary battery according to any one of claims 1 to 5, wherein the first binder is a compound having a structural unit represented by the following formula (1).
第一結着剤と第二結着剤とのSP値差の絶対値が、3以上である請求項1ないし請求項6のいずれかに記載の全固体二次電池。   The all-solid-state secondary battery according to any one of claims 1 to 6, wherein an absolute value of an SP value difference between the first binder and the second binder is 3 or more. 第一結着剤が、下記式(2)で表される構成単位を有する化合物である請求項1ないし請求項5のいずれかに記載の全固体二次電池。
The all-solid secondary battery according to any one of claims 1 to 5, wherein the first binder is a compound having a structural unit represented by the following formula (2).
第一結着剤と第二結着剤とのSP値差の絶対値が、1以上である請求項1ないし請求項5および請求項8のいずれかに記載の全固体二次電池。   9. The all-solid-state secondary battery according to claim 1, wherein an absolute value of a difference in SP value between the first binder and the second binder is 1 or more. 非極性溶媒に、正極活物質と固体電解質と非極性溶媒不溶性の第一結着剤と非極性溶媒可溶性の第二結着剤とを添加する正極合剤調製工程と、非極性溶媒に、負極活物質と固体電解質と非極性溶媒不溶性の第一結着剤と非極性溶媒可溶性の第二結着剤とを添加する負極合剤調製工程と、固体電解質と非極性溶媒不溶性の第一結着剤と非極性溶媒可溶性の第二結着剤とを混合する固体電解質層形成工程とのいずれか一つ以上の工程を含む全固体二次電池の製造方法。   A positive electrode mixture preparation step of adding a positive electrode active material, a solid electrolyte, a nonpolar solvent-insoluble first binder and a nonpolar solvent-soluble second binder to a nonpolar solvent, and a nonpolar solvent, a negative electrode A negative electrode mixture preparation step of adding an active material, a solid electrolyte, a non-polar solvent-insoluble first binder and a non-polar solvent-soluble second binder, and a solid electrolyte and a non-polar solvent-insoluble first binder A method for producing an all-solid-state secondary battery, comprising at least one of a solid electrolyte layer forming step of mixing an agent and a non-polar solvent-soluble second binder.
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