JP6945833B2 - Electrodes and their manufacturing methods and all-solid-state lithium-ion batteries - Google Patents

Description

The present invention relates to an electrode, a method for manufacturing the electrode, and an all-solid-state lithium ion battery. More specifically, the present invention relates to an electrode used in an all-solid-state lithium-ion battery having a structure in which a solid electrolyte is arranged between a pair of electrodes, a method for producing the same, and an all-solid-state lithium-ion battery.

In a lithium ion battery (hereinafter, also simply referred to as "Li ion battery"), when charging, lithium dissolves as ions from the positive electrode, moves to the negative electrode, and is occluded in the negative electrode. Further, it is a secondary battery having a reaction form in which lithium ions return from the negative electrode to the positive electrode when discharged.

In the field of Li-ion batteries, research is underway to replace electrolytes containing flammable organic solvents with solid electrolytes for reasons such as simplification of safety devices and excellent manufacturing costs and productivity. Has been done. At the same time, the development of electrodes corresponding to the use of this solid electrolyte is underway.

Such an electrode is generally formed by laminating an active material layer on a current collector. If it is a positive electrode, for example, a composite oxide (positive electrode active material) capable of occluding and releasing lithium ions is blended in the active material layer as a main component. To form this active material layer, the active material is mixed with a binder resin together with auxiliary components such as a conductive agent and a solid electrolyte, and an appropriate amount of solvent is added to form a paste or slurry, which is then applied onto the current collector. It is done in. In recent years, it has been attempted to form an active material layer on a current collector by using an electrophoresis method in order to prepare a uniform and accurate active material layer rather than forming an active material layer by coating. (See Patent Documents 1 to 3). If the active material layer is formed by using such an electrophoresis method, the binder resin can be eliminated, so that the ratio of the active material in the active material layer and the filling density thereof can be improved, and the battery capacity can be increased. It becomes.

Japanese Patent Application Laid-Open No. 2014-534592 Japanese Patent Publication No. 2014-535141 Japanese Unexamined Patent Publication No. 2002-42791

However, the techniques disclosed in Patent Documents 1 to 3 only disclose that the active material is simply deposited by electrophoresis, and it is assumed that a plurality of components are arranged so as to have an arbitrary structure. Therefore, there is a problem that it is not possible to obtain a structure in which a plurality of components are deposited in a structure-controlled manner in the electrode.

The structure in the active material layer affects the occlusion and release of lithium ions and the movement of electrons, and greatly affects the electrical characteristics such as the charge / discharge characteristics of the battery. Therefore, an electrode in which the distribution state and contact state of each component in the active material layer are more highly controlled is desired. However, the techniques disclosed in Patent Documents 1 to 3 have a problem that such an electrode cannot be provided.

In particular, from the viewpoint of battery capacity, the amount of accumulated positive electrode active material is required, but if the film is simply thickened (increasing the amount of positive electrode active material) to increase the accumulated amount, the balance with the solid electrolyte becomes poor. Therefore, there is a problem that the ionic conductivity is lowered and it becomes difficult to obtain good battery characteristics. Therefore, it is desired to provide an electrode whose structure is controlled so as to further improve the battery characteristics and a method for manufacturing the electrode.

The present invention has been made in view of the above problems, and an electrode formed by controlling the distribution of each component such as an active material and a solid electrolyte, a method for producing this electrode, and this electrode are used. It is an object of the present invention to provide an all-solid-state lithium ion battery used.

In order to achieve this object, the electrode according to claim 1 is a electrode used in an all-solid-state lithium ion battery having a structure in which a solid electrolyte is arranged between a pair of electrodes, and contains an active material as a main component. The active material layer is provided with a solid electrolyte layer containing a solid electrolyte as a main component, and the active material layer is a resin having an ion exchange group, and the solid electrolyte or a part of the ion exchange group is used as the solid electrolyte or a part thereof. The precursor contains an ion-exchange resin in which the first counter ion ionized in a poor solvent and an aprotonic solvent is ion-bonded.

The electrode according to claim 2 is the electrode according to claim 1. The ion exchange resin contained in the active material layer has an acidic group as the ion exchange group, and all or a part of the acidic group is present. It is provided with a cation of an organic onium salt as the first pair ion.

The electrode according to claim 3 is the electrode according to claim 2, wherein the ion exchange resin is a polymer having a unit derived from styrene and a unit derived from olefin in the main chain, and the acidic group is a sulfonic acid. A group or a group derived from a sulfonic acid.

The electrode according to claim 4 is the electrode according to claim 2 or 3, and the organic onium salt is a quaternary phosphonium salt.

The electrode according to claim 5 is the electrode according to any one of claims 1 to 4, having a laminated structure in which the solid electrolyte layer is interposed between two layers of the active material layer, and two layers. It has at least one of the laminated structures in which the active material layer is interposed between the layers of the solid electrolyte layer.

The electrode according to claim 6 is the electrode according to any one of claims 1 to 5, wherein the solid electrolyte is a sulfide-based solid electrolyte.

The electrode according to claim 7 is the electrode according to any one of claims 1 to 6, wherein the active material is a positive electrode active material.

The method for producing an electrode according to claim 8 is a method for producing the electrode used in an all-solid-state lithium-ion battery having a structure in which a solid electrolyte is arranged between a pair of electrodes, and includes an active material. By the first deposition step of depositing the active material to form the active material layer by electrophoresis in the active material-containing liquid, and by electrophoresis in the solid electrolyte-containing liquid containing the solid electrolyte and / or its precursor. A second deposition step of depositing the solid electrolyte and / or its precursor to form a solid electrolyte layer or a precursor layer thereof adjacent to the active material layer formed in the first deposition step is provided. In one deposition step, when the active material layer is formed after the solid electrolyte layer is formed, in an active material-containing liquid which is a poor solvent for the solid electrolyte or its precursor and uses an aprotonic solvent as a dispersion medium. The active material is electrolyzed in a state where an ion exchange resin having a first pair ion to be ionized in the dispersion medium is attached.

The method for manufacturing an electrode according to claim 9 is the method for manufacturing an electrode according to claim 8, wherein at least one of the first deposition step and the second deposition step is performed a plurality of times to obtain the active material layer and the active material layer. The solid electrolyte layer or a precursor layer thereof is alternately laminated.

The method for producing an electrode according to claim 10 is the method for producing an electrode according to claim 8 or 9, wherein an ion exchange resin is attached to the active material, and all or a part of the counter ions of the ion exchange group is attached. A pretreatment step of ion-exchange with the first pair ion is provided, and the first deposition step deposits an active material to which an ion exchange resin ion-exchanged in the pretreatment step is attached.

The method for producing an electrode according to claim 11 is the method for producing an electrode according to any one of claims 8 to 10, wherein the ion exchange resin has a styrene-derived unit and an olefin-derived unit in the main chain. However, it is a polymer having a sulfonic acid group or a sulfonic acid-derived group as an ion exchange group.

The method for producing an electrode according to claim 12 is the method for producing an electrode according to claim 11, wherein in the pretreatment step, a sulfonic acid group or a pair ion of a sulfonic acid-derived group is converted into a cation of an organic onium salt. It is to be replaced.

The electrode manufacturing method according to claim 13 is the electrode manufacturing method according to any one of claims 8 to 12, wherein the dispersion medium used in the first deposition step is a solvent having a dielectric constant of 15 or less. ..

The all-solid-state lithium-ion battery according to claim 14 includes the electrode according to any one of claims 1 to 7.

According to the electrode of the present invention, it is used in an all-solid-state lithium-ion battery having a structure in which a solid electrolyte is arranged between a pair of electrodes, and an active material layer containing an active material as a main component and a solid. The electrode has a solid electrolyte layer containing an electrolyte as a main component, that is, has a layered structure. In other words, with this configuration, any layer structure can be introduced into the active material layer.

Here, in order to control the layer thickness of each layer precisely and inexpensively, it is desirable to form each layer by electrophoresis. Generally, a protic solvent or a polar solvent is used as a dispersion medium for electrophoresis. The solid electrolyte layer or its precursor layer is often easily reacted and dissolved in such a solvent, and the layer structure cannot be maintained. On the other hand, if a poor solvent of the solid electrolyte or its precursor is used as the dispersion medium, the reaction and dissolution of the solid electrolyte or its precursor can be suppressed to maintain the layer structure, but the migration of an active material having a weak surface charge can be performed. Make it difficult. Therefore, an ion exchange resin in which the first pair ion ionized in the poor solvent and aprotonic solvent of the solid electrolyte or its precursor is ion-bonded to all or part of the ion exchange group is previously attached to the active material. By doing so, a sufficient surface charge can be imparted to the active material even in the above-mentioned poor solvent. Therefore, the active material can be satisfactorily migrated in such a poor solvent and deposited on the solid electrolyte to form a layer while avoiding the dissolution of the solid electrolyte or its precursor. In other words, by making the active material layer contain an ion exchange resin, there is an effect that an electrode having a layer structure in which the layer thickness is precisely controlled can be realized.

Further, according to the electrode of the present invention, a laminated structure in which a solid electrolyte layer is interposed between the layers of the two active material layers and a laminated structure in which the active material layer is interposed between the layers of the two solid electrolyte layers. Since it has a laminated structure of at least one of the above, there is an effect that an electrode in which a plurality of active material layers and a solid electrolyte layer are alternately laminated can be obtained.

When the active material layer and the solid electrolyte layer are alternately laminated, the battery capacity can be improved by increasing the number of active material layers. A method of improving the battery capacity by simply thickening the active material layer can be considered, but when the electrolyte is a solid electrolyte, it is difficult for the electrolyte to penetrate into the electrode, so the active material layer is a thick film. When it becomes, the ionic conductivity decreases. However, in this electrode, since the active material layer and the solid electrolyte layer having a controlled film thickness are alternately laminated, ionic conductivity can be ensured, and both increase in battery capacity and ionic conductivity can be ensured at the same time. It has the effect of being able to do it.

According to the method for producing an electrode of the present invention, it is a method for producing an electrode used in an all-solid-state lithium-ion battery having a structure in which a solid electrolyte is arranged between a pair of electrodes, and is an active material in the first deposition step. The active material is deposited to form an active material layer by electrophoresis in an active material-containing liquid containing By the second deposition step, the solid electrolyte and / or its precursor is deposited and formed by electrophoresis in a solid electrolyte-containing liquid containing the solid electrolyte and / or its precursor. Here, in the first deposition step, when the active material layer is formed after the solid electrolyte layer is formed, the active material is contained in a poor solvent of the solid electrolyte and / or its precursor and using an aprotonic solvent as a dispersion medium. In the liquid, electrophoresis is carried out in a state where an ion exchange resin having a first counter ion that is ionized in the dispersion medium is attached to the active material.

The solid electrolyte or its precursor and the active material differ in their solubility in a solvent and the strength of surface charge in a liquid. In general, in electrophoresis, a mixed substance (electrophoresis substance) is often electrophoresed using a polar solvent (protic solvent) as a dispersion medium. This is because the larger the polarity of the dispersion medium, the higher the surface charge of the object to be electrophoresed, and the easier it is to migrate. Here, when the surface charge of the active material is so weak that it cannot be migrated in the selected solvent, it is conceivable to run it using a solvent having a higher polarity. However, since the solid electrolyte or its precursor is often dissolved in a more polar solvent, if the solid electrolyte layer or its precursor layer is already formed, the solid electrolyte layer or its precursor is formed. A situation occurs in which the precursor layer is dissolved.

This production method suppresses the dissolution of the already prepared solid electrolyte layer or its precursor layer by using an active material-containing liquid which is a poor solvent for the solid electrolyte or its precursor and uses an aprotic solvent as a dispersion medium. can. In addition, the reaction with the constituent components caused by the protic solvent can be avoided. On the other hand, since the active material is in a state where an ion exchange resin having a first counterion that is ionized in this poor solvent is attached, the surface charge is increased by the action of the ion exchange resin, and the active material is allowed to run well. Can be done. Therefore, it is possible to both suppress the dissolution of the solid electrolyte layer or its precursor layer and deposit the active material by electrophoresis, and manufacture an electrode in which the solid electrolyte layer or its precursor layer and the active material layer are laminated. It has the effect of being able to. Further, since any of the layers can be formed by electrophoresis, it is possible to produce an electrode structure in which the layer thickness of each layer is appropriately controlled.

Further, according to the electrode manufacturing method of the present invention, at least one of the first deposition step and the second deposition step is performed a plurality of times, and the active material layer and the solid electrolyte layer or its precursor layer are alternately alternated. Therefore, there is an effect that an electrode in which a plurality of active material layers and a solid electrolyte layer are alternately laminated can be manufactured.

When the active material layer and the solid electrolyte layer are alternately laminated, the battery capacity can be improved by increasing the number of active material layers. A method of improving the battery capacity by simply thickening the active material layer can be considered, but when the electrolyte is a solid electrolyte, it is difficult for the electrolyte to penetrate into the electrode, so the active material layer is a thick film. When it becomes, the ionic conductivity decreases. However, in the method for producing this electrode, an electrode in which an active material layer having a controlled film thickness and a solid electrolyte layer (or a precursor layer thereof) are alternately laminated can be produced, so that ionic conductivity can be ensured. This has the effect of providing an electrode that achieves both an increase in battery capacity and ensuring ionic conductivity.

Further, according to the method for producing an electrode of the present invention, a pretreatment in which an ion exchange resin is further attached to an active material and all or a part of the pair ions of the ion exchange group is ion-exchanged with the first pair ion. The first deposition step includes a step of depositing an active material to which an ion exchange resin ion-exchanged in the pretreatment step is attached. As a result, various pairs can be selected and exchanged as the pair ions of the ion exchange group of the ion exchange resin attached to the active material, and the pair ions of the ion exchange group are protons (H ⁺ ) and hydroxide ions (H +). Compared with the case of OH ⁻ ), ionization of a counter ion (first pair ion) can be promoted in a poor solvent of a solid electrolyte or a precursor thereof. Therefore, even when it is used as a dispersion medium for an active material-containing liquid, there is an effect that a sufficient surface charge can be imparted to the contained active material by the action of ionizing counterions.

Further, according to the method for producing an electrode of the present invention, the ion exchange resin used in the pretreatment step is a polymer having a unit derived from styrene and a unit derived from olefin in the main chain, and the acidic group is sulfonic acid. It is assumed to be an acid group or a group derived from a sulfonic acid. Since the sulfonic acid group is a strong acid, its protons are easily ionized, and the cation exchange reaction can proceed efficiently. In addition, polymers having a styrene-derived unit and an olefin-derived unit in the main chain are lipophilic. Since the poor solvent of the solid electrolyte or its precursor is often a non-protic solvent, it has an affinity for an ion exchange resin having such a structure, and the dispersion of the active material to which the ion exchange resin is attached is promoted. There is an effect. Therefore, there is an effect that the electrophoresis of the active material can be performed even better. The sulfonic acid-derived group is a concept including a sulfonic acid proton replaced with another ion by cation exchange. That is, the acidic group includes those in the salt type. As a result, even if the active material reacts with an acid (proton), the ion exchange resin (ion exchange group) is a salt type, so that the reaction is suppressed and the ion exchange resin is attached to the active material. Degeneration of the active material can be avoided in treatment and the like.

Further, according to the method for producing an electrode of the present invention, the poor solvent used in the second deposition step is a solvent having a dielectric constant of 15 or less, so that the solid electrolyte layer or its precursor layer can be reliably dissolved. It has the effect of being able to suppress it.

Since the all-solid-state lithium-ion battery of the present invention includes the electrode of the present invention, there is an effect that the all-solid-state lithium-ion battery can be charged and discharged by using the electrode having this novel configuration.

It is explanatory drawing explaining the outline of the electrode structure of this invention, and the all-solid-state lithium ion battery which has the electrode. It is explanatory drawing explaining an example of the signal which has the asymmetric waveform on the positive electrode side and the negative electrode side. It is explanatory drawing explaining another example of the signal which has the asymmetric waveform on the positive electrode side and the negative electrode side. It is explanatory drawing explaining another example of the signal which has the asymmetric waveform on the positive electrode side and the negative electrode side. It is explanatory drawing explaining another example of the signal which has the asymmetric waveform on the positive electrode side and the negative electrode side. It is explanatory drawing explaining another example of the signal which has the asymmetric waveform on the positive electrode side and the negative electrode side. It is explanatory drawing explaining an example of the deposition form of a particle. It is explanatory drawing explaining another example of the deposition form of a particle. It is explanatory drawing explaining the morphology which deposited different kinds of particles alternately. It is a figure which showed the relationship between the electrophoresis time and the layer thickness of an active material layer and a solid electrolyte layer. It is a micrograph of the electrode structure in the 2nd Example. It is explanatory drawing explaining the jig which concerns on Reference Example 1. FIG. It is a micrograph of the electrode structure in the 4th Example. It is a figure which showed the charge / discharge test result of the battery formed in Reference Example 2. FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings.
[1] Electrode The electrode (2) of the present invention is an electrode (1) used for an all-solid-state lithium ion battery (1) having a structure in which a solid electrolyte body (3) is arranged between a pair of electrodes (2a, 2b). 2).

The electrode (2) is characterized by including an active material layer (21) containing an active material as a main component and a solid electrolyte layer (22) containing a solid electrolyte as a main component (see FIG. 1).

The active material layer 21 and the solid electrolyte layer 22 are usually laminated so as to be in contact with each other on their main surfaces. High conductivity of Li ions can be obtained by contacting each other with wide surfaces.

Further, although the electrode including the active material layer 21 and the solid electrolyte layer 22 may be obtained in any way, it can be obtained by using electrophoresis as described later. In this case, the active material layer 21 and the solid electrolyte layer 22 are laminated on the conductive surface 251 of the base material 25 having a conductive surface (conductive surface).

Further, in that case, either of the active material layer 21 and the solid electrolyte layer 22 may be brought into contact with the conductive surface 251. However, it is preferable that the active material layer 21 is brought into contact with the conductive surface 251. That is, the electrode has a structure in which the active material layer 21 and the solid electrolyte layer 22 are laminated in this order on the conductive surface 251 of the base material 25 (see FIG. 1).

The specific laminated form in the electrode 2 is not particularly limited, but one of the active material layer 21 and the solid electrolyte layer 22 may be sandwiched between the other layers. preferable. Therefore, it is preferable to provide two or more layers of at least one of the active material layer 21 and the solid electrolyte layer 22.

That is, the electrode 2 has (1) a laminated structure in which the solid electrolyte layer 22 is interposed between the two layers of the active material layer 21, and (2) the active material layer 21 is interposed between the layers of the two solid electrolyte layers 22. It is preferable to have at least one of the laminated structures obtained. These laminated structures may include only one of them, but may include both laminated structures. The case where both laminated structures are provided means that the active material layer 21 having two or more layers and the solid electrolyte layer 22 having two or more layers are alternately laminated to have a laminated structure. By forming the sandwich-shaped laminated structure while controlling the thickness of each layer in this way, it is possible to obtain more excellent Li ion conductivity as compared with the case where the sandwich-shaped laminated structure is not provided.

The number of layers of the active material layer 21 and the solid electrolyte layer 22 is not particularly limited, but may be, for example, one layer or more and 50 layers or less, respectively. The number of layers is preferably 2 or more and 25 or less, and more preferably 2 or more and 10 or less.

Further, the active material layer 21 and the solid electrolyte layer 22 may be laminated with the same thickness, but can be laminated with different thicknesses. In this case, it is preferable to form the solid electrolyte layer 22 thinner than the active material layer 21. In this way, when the solid electrolyte layer 22 is thinned with respect to the active material layer 21, the distance between the laminated active material layers is larger than that when the solid electrolyte layer 22 is thickened with respect to the active material layer 21. By reducing the size, the electron conductivity (conductivity) in the vertical direction can be improved. The ratio of the thickness of the active material layer 21 (D ₂₁ ) to the thickness of the solid electrolyte layer 22 (D ₂₂ ) (D ₂₂ / D ₂₁ ) is not limited, but is, for example, 0.05 or more and 1 or less. can do. This ratio (D ₂₂ / D ₂₁ ) is further preferably 0.05 or more and 0.5 or less, and more preferably 0.05 or more and 0.2 or less. The ratio of the layer thickness does not have to be the same for all layers, and may be different for each layer. Further, a part of the layers in the electrode may be formed at such a ratio, and all the layers may be formed at such a ratio.

The specific thickness of each layer is not limited, but for example, the thickness D ₂₁ of the active material layer 21 can be 0.5 μm or more and 40 μm or less. The thickness (D ₂₁ ) is further preferably 1 μm or more and 25 μm or less, and more preferably 4 μm or more and 8 μm or less. Similarly, for example, the thickness D ₂₂ of the solid electrolyte layer 22 can be 0.25 μm or more and 40 μm or less. The thickness (D ₂₂ ) is further preferably 0.25 μm or more and 25 μm or less, more preferably 0.25 μm or more and 8 μm or less, and particularly preferably 0.25 μm or more and 0.5 μm or less. It should be noted that each layer may be designed not only based on the layer thickness but also based on the number of particles to be laminated. In such a case, the number of particles laminated on the active material layer 21 is preferably 1 to 4, more preferably 1 to 3, and particularly preferably 1 to 2 (particle 1). 2 or more and 2 or less). However, it is not limited to this.

The thickness of the active material layer 21 (D ₂₁ ) and the thickness of the solid electrolyte layer 22 (D ₂₂ ) shall be measured in an image in which the electrode cross section is magnified 10,000 times by an electron microscope. Specifically, the average value of the actual dimensions measured at five different points of each layer is defined as the thickness D ₂₁ or the thickness D ₂₂ .

The active material layer 21 is a layer containing an active material as a main component. The fact that the active material is the main component means that the active material is contained in an amount of 50% by mass or more when the entire active material layer 21 is 100% by mass. This ratio is preferably 50% by mass or more and 100% by mass or less, and can be 60% by mass or more and 98% by mass or less, and further 70% by mass or more and 95% by mass or less.

Examples of other components other than the active material that can be contained in the active material layer include solid electrolytes and conductive aids. By containing these components, a conduction path for Li ions (due to a solid electrolyte) and an electron conduction path (due to a conductive aid) can be formed in the electrode.

Only one of these other components may be used, or two or more thereof may be used in combination. When other components are contained, assuming that the total mass of the entire active material layer 21 is 100% by mass, the content ratio of the other components is 50% by mass or less. This content ratio can be 2% by mass or more and 40% by mass or less, and further can be 5% by mass or more and 30% by mass or less.

The solid electrolyte and the conductive auxiliary agent will be described later.

The active material is a substance capable of inserting and removing lithium ions, or alloying and dealloying. Among the active materials, as the active material for the positive electrode (hereinafter, also simply referred to as “positive electrode active material”), a composite oxide containing lithium capable of inserting and removing lithium ions can be used.

Specific examples _{thereof include lithium composite oxides such as LiMO 2} , Li ₂ MO ₃ and LiM ₂ O ₄ , and lithium composite oxides in which these are mixed. However, the above-mentioned "M" is one kind of metal element selected from at least Co, Ni and Mn among Co, Ni, Mn and Al.

Among the above, examples of the LiMO ₂ type lithium composite oxide include LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , Li ₂ MnO ₃ , and Li (Ni _x Co _1-x ) O ₂ {however, 0 <x <1. .. For example, Li (Ni _0.8 Co _0.2 ) O ₂ etc.}, Li (Ni _x Mn _1-x ) O ₂ {However, 0 <x <1. For example, Li (Ni _0.5 Mn _0.5 ) O ₂ etc.}, Li (Ni _x Mn _y Co _1-x-y ) O ₂ {However, x> 0, y> 0, x + y <1. For example, Li (Ni _1/3 Mn _1/3 Co _1/3 ) O ₂ etc.}, Li (Ni _x Co _y Al _1-xy ) O ₂ {However, x> 0, y> 0, x + y < It is 1. For example, Li (Ni _0.8 Co _0.15 Al _0.05 ) O ₂ etc.} and the like can be mentioned. Only one of these may be used, or two or more thereof may be used in combination.

Among the above, as LiM ₂ O ₄ type lithium composite oxides, LiCo ₂ O ₄ , LiNi ₂ O ₄ , LiMn ₂ O ₄ , Li (Co _x Ni _2-x ) O ₄ {However, 0 < x <2}, Li (Co _x Mn _2-x ) O ₄ {However, 0 <x <2}, Li (Al _x Mn _2-x ) O ₄ {However, 0 <x <2 Yes}, Li (Mn _x Ni _2-x ) O ₄ {However, 0 <x <2. For example, Li (Mn _1.5 Ni _0.5 ) O ₄ etc.} and the like can be mentioned. Only one of these may be used, or two or more thereof may be used in combination.

Among the above, LiMO _{type 2} lithium composite oxide is preferable, and Li (Ni _x Mn _y Co _1-x-y ) O ₂ {however, x> 0, y> 0, x + y <1. } (Hereinafter, also simply referred to as "NMC") is preferable.

Among the active materials, the active material for the negative electrode (hereinafter, also simply referred to as “negative electrode active material”) includes carbon-based materials (carbon-based materials as the negative electrode active material), various oxides, magnesium compounds, tin compounds, and antimony compounds. , Metallic lithium and the like can be used.

Among these, examples of carbon-based materials include graphite, graphene, carbon black, carbon nanotubes, and lithium carbon compounds (Li _x C ₆ ). Examples of the oxide include SiO, SnO, SnO ₂ , TiO ₂ , Nb ₂ O ₅ , WO ₂ , MoO ₂ , Li ₄ Ti ₅ O _{12 and the} like. Examples of the magnesium compound include Mg ₂ Si, Mg ₂ Ge, Mg ₂ Sn and the like. The tin _{compounds, SbSn, SnS 2, CoSn 2} , Ni 3 Sn 2, Cu 6 Sn 5, Ag 3 Sn, LaSn 3, La 3 Co 2 Sn 7, V 2 Sn 3 FeSn 2 , and the like. Examples of the antimony compound include SbSn, Ag ₃ Sb, CeSb ₃ , CoSb ₃ , InSb, Ni ₂ MnSb and the like. Only one of these may be used, or two or more thereof may be used in combination.

Further, the active material contained in the active material layer 21 can be made granular. That is, a granular active material (hereinafter, also simply referred to as “granular active material”) can be used. The particle size of the granular active material is not particularly limited, but it is more preferable to simultaneously contain at least two kinds of granular active materials having different particle sizes, that is, a larger diameter granular active material and a smaller diameter granular active material. As a result, both the filling property and the smoothness of the active material layer 21 can be achieved at the same time. More specifically, a granular active material (large-diameter active material) having a particle size of more than 0.5 μm and 10 μm or less and a spherical granular active material having a particle size of 1 nm or more and 500 nm or less (a large-diameter active material). Small diameter active material) and preferably.

Further, the active material layer 21 contains an ion exchange resin. This ion exchange resin is contained in a state of being attached to the active material. Further, as will be described later, this electrode can be manufactured by using electrophoresis. By depositing the active material and the solid electrolyte by this electrophoresis, the layer thickness can be highly controlled, and a pre-designed laminated structure main electrode can be obtained. In other words, it is preferable to use electrophoresis in order to realize a pre-designed laminated structure with high accuracy, but in such a case, it is a requirement that the ion exchange resin is attached to the active material. Therefore, the active material layer 21 of this electrode contains an ion exchange resin.

Specifically, the ion exchange resin is a polymer to which an ion exchange group is bonded. The ion exchange resin is not particularly limited as long as it is a polymer compound in which an ion exchange group is introduced, and may be an ion exchange resin known per se. Examples of the polymer compound that serves as the main skeleton of the ion exchange resin include styrene-based polymers such as polystyrene and poly (α-methylstyrene), aromatic vinyl polymers such as polyvinyltoluene, polyvinylbenzyl chloride, polyvinylbiphenyl, and polyvinylnaphthalene. Vinyl halide polymers such as polyvinyl chloride, polyolefins such as polyethylene, polypropylene and polybutylene, halogenated polyolefins such as polytetrafluoroethylene, nitrile polymers such as polyacrylonitrile, methyl polymethacrylate, glycidyl polymethacrylate and polyacrylic acid. Examples thereof include (meth) acrylic polymers such as ethyl, but the present invention is not limited to this. The polymer may be a polymer obtained by copolymerizing a single monomer and a cross-linking agent, a polymer obtained by polymerizing a plurality of monomers and a cross-linking agent, or a blend of two or more kinds of polymers. It may be a thing.

The ion exchange resin contained in this electrode is preferably one in which the polymer serving as the main chain has an affinity for a non-polar solvent. A polymer having a styrene-derived unit and an olefin-derived unit is preferably used, and a block copolymer of a polystyrene-based resin and a polyolefin-based resin is particularly preferable. As described above, a lipophilic polymer having a main chain having a unit derived from styrene and a unit derived from olefin has an affinity for a non-polar solvent and has good solubility in such a solvent. Here, in the present invention, the main chain means a portion other than the ion exchange group and which is a skeleton of a polymer structure including a repeating unit.

By using such an ion exchange resin, even if the surface charge originally possessed by the active material is weak, the surface charge of the active material is remarkably increased in a non-polar solvent by treating the active material in advance with the ion exchange resin. The active material can be deposited by electrophoresis. Therefore, it is possible to obtain the present electrode in which the layer structure of the active material layer and the solid electrolyte layer is well formed.

The ion exchange resin contained in the present electrode may be either a cation (cation) exchange resin or an anion (anion) exchange resin.

If the ion exchange group contained in the above ion exchange resin is a cation exchange resin, cation exchange groups such as a sulfonic acid group, a carboxylic acid group, an iminodiacetic acid group, a phosphoric acid group, and a phosphoric acid ester group are exemplified. In the case of an anion exchange resin, anion exchange groups such as a quaternary ammonium group, a tertiary amino group, a secondary amino group, a primary amino group, a polyethyleneimine group, a tertiary sulfonium group and a phosphonium group can be mentioned. In addition, these ion exchange groups may have a substituent as long as it does not interfere with the ion exchange function. The ion exchange group is preferably strongly acidic or strongly basic. Examples of such strongly acidic substances include sulfonic acid groups. Further, a quaternary ammonium group is exemplified as a strongly basic one.

For example, as an example of the anion exchange resin, it may be a polycation collectively called Polyquaternium, and those containing vinylpyrrolidone, acrylamide, methacrylate and the like in the repeating unit can be exemplified, and in particular, the structure of vinylpyrrolidone. Is desirable. Examples of polyquaternium containing a vinylpyrrolidone structure include polyquaternium 11, polyquaternium 16, polyquaternium 28, polyquaternium 44, polyquaternium 46, and the like.

Among the ion exchange groups, the cation exchange group that becomes anionic after the dissociation of the counter ion is an acidic group, and in the present embodiment, not only the one having a proton but also the salt by cation exchange. The mold (acid-derived group) is also included in the acidic group. For example, when the cation exchange group is a strongly acidic sulfonic acid group (−SO ₃ H), −SO ₃ ⁻ is a fixed ion and a proton (H ⁺ ) is a counterion. This counterion proton can be exchanged for another cation by an ion exchange treatment (ion exchange reaction). By such an ion exchange reaction, the ion exchange group can be made into a salt type.

In addition, anion exchange groups that become cationic after dissociation of counter ions are basic groups, and not only those having hydroxide ions but also those that become salt-type by anion exchange (base-derived). The basis of) shall also be included. For example, the anion-exchange groups and is strongly basic quaternary ammonium groups such as trimethyl ammonium group _{(-R 3 NOH), -R 3} N + fixed ions, hydroxide ion (OH ^-), such as pairs Become an ion. Hydroxide ions and the like can be exchanged for other anions by an ion exchange treatment (ion exchange reaction). By such an ion exchange reaction, the ion exchange group can be made into a salt type.

In the ion exchange resin contained in the present invention, the ion ionized from the ion exchange group in an organic solvent (non-protic solvent) corresponds to the first counterion according to the claim. The ion exchange resin contained in the present invention preferably has at least a part of its ion exchange group in the form of a salt. Further, since the ion exchange group containing a proton or hydroxide ion can be formed into a salt type by an ion exchange reaction, the counterion can be appropriately exchanged to provide a desired counterion. Here, in the present invention, when the ion exchange group is an anion exchange group, a salt type having an anion of a lithium salt as a counter ion is preferably used. When the ion exchange resin is a polycation such as polyquaternium, it can be a salt type having an anion of a substance called an anionic surfactant as a counterion. For example, alkylbenzene sulfonates, α-sulfo fatty acid methyl ester salts, dialkyl sulfosulfates, alkyl sulfate ester salts and the like are exemplified. Particularly preferably, it is an anionic surfactant having an alkyl chain having 10 or more carbon atoms, and examples thereof include sodium dodecylbenzenesulfonate and sodium bis (2-ethylhexyl) sulfosuccinate. ..

When the ion exchange group is a cation exchange group, a salt-type product having a cation of an organic onium salt as a counter ion is preferably used. Examples of such organic onium salts include bromonium salt, iodonium salt, oxonium salt, sulfonium salt, alsonium salt, ammonium salt (quaternary), ammonium fluoride (quaternary), ammonium chloride (quaternary), and ammonium bromide (quaternary). Examples thereof include quaternary), ammonium iodide (quaternary), ammonium hydroxide (quaternary), ammonium polyhalide, and phosphonium salt. In particular, from the viewpoint of dissolution stability, it is preferable to use a quaternary salt, and a quaternary ammonium salt and a quaternary phosphonium salt are more preferable. As a result, when the electrode is prepared by electrophoresis (the active material and the solid electrolyte are deposited respectively), the counterion ionized from the ion exchange group is stabilized in the solvent in the non-polar solvent, so that the active material can be used as the active material. Not only can the applied charge be strengthened, but the dispersibility of the active material in the solvent can also be improved. Therefore, the electrophoresis can be performed more stably.

As a result, when the electrode is produced by electrophoresis, the counterion can be easily ionized from the ion exchange group in a non-polar solvent or a non-polar solvent, and the charge given to the active material can be strengthened.

The solid electrolyte layer 22 is a layer containing a solid electrolyte as a main component. The fact that the solid electrolyte is the main component means that the solid electrolyte layer 22 contains 50% by mass or more when the entire solid electrolyte layer 22 is 100% by mass. This ratio is preferably 50% by mass or more and 100% by mass or less, and can be 60% by mass or more and 98% by mass or less, and further 70% by mass or more and 95% by mass or less.

Examples of other components other than the solid electrolyte that can be contained in the solid electrolyte layer include active materials and conductive auxiliaries. Only one of these other components may be used, or two or more thereof may be used in combination. When other components are contained, assuming that the entire solid electrolyte layer 22 is 100% by mass, the content ratio of the other components is 50% by mass or less. This content ratio can be 2% by mass or more and 40% by mass or less, and further can be 5% by mass or more and 30% by mass or less.

The active material is as described above. The conductive auxiliary agent will be described later.

A solid electrolyte is a substance that can serve as a conduction path for Li ions. Specifically, Li _1.07 Al _0.69 Ti _1.46 (PO ₄ ) ₃ , Li _1.5 Al _0.5 Ge _1.5 (PO ₄ ) ₃ , Li _3.25 Ge _0.25 P. _{0.75 S 4, Li 10 GeP 2} S 12, Li 6 PS 5 Cl, 30Li 2 S · 26B 2 S 3 · 44LiI, 63Li 2 S · 36SiS 2 · 1Li 3 PO 4, 57Li 2 S · 38SiS 2 · 5Li ₄ SiO ₄ , 70Li ₂ S / 30P ₂ S ₅ , 50Li ₂ S / 50GeS ₂ , Li _3.25 P _0.95 S ₄ , Li _3.25 Ge _0.25 P _0.75 S ₄ , Li ₃ PS ₄ , Li ₄ P ₃ S ₁₁ , Li ₇ P ₃ S _{11, and} other sulfide solid electrolytes. Only one of these may be used, or two or more thereof may be used in combination.

Furthermore, La _0.5 Li _0.5 TiO ₃ , La _0.51 Li _0.34 TIM _2.94 , Li _1.3 Al _0.3 Ti _1.7 (PO ₄ ) ₃ , Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₅ La ₃ Nb ₂ O ₁₂ , 50Li ₄ SiO ₄ , 50Li ₃ BO ₃ , Li _2.9 PO _3.3 N _0.46 , Li _3.6 Si _0.6 P _0.4 O _4, etc. Non-sulfide solid electrolytes of. Only one of these may be used, or two or more thereof may be used in combination.

Of these, sulfide solid electrolytes are preferred. Further, a sulfide glass solid electrolyte or a non-crystalline sulfide solid electrolyte of a sulfide glass ceramic solid electrolyte is more preferable. The non-crystalline sulfide solid _{electrolyte, 30Li 2 S · 26B 2 S} 3 · 44LiI, 63Li 2 S · 36SiS 2 · 1Li 3 PO 4, 57Li 2 S · 38SiS 2 · 5Li 4 SiO 4, 70Li 2 S · 30P ₂ S ₅ , 50Li ₂ S / 50GeS ₂ , Li _3.25 P _0.95 S ₄ , Li _3.25 Ge _0.25 P _0.75 S ₄ , Li ₃ PS ₄ , Li ₄ P ₃ S ₁₁ , Examples thereof include _{Li 7} P ₃ S _11.

Among these, further, Li, include the elements of P and S, noncrystalline sulfide solid electrolyte containing PS ₄ bond. Examples of such sulfide solid electrolytes include Li ₃ PS ₄ , Li ₄ P ₃ S ₁₁ , Li ₇ P ₃ S _{11 , 70Li 2} S / 30P ₂ S ₅ , Li _3.25 P _0.95 S _4. Can be mentioned. Only one of these may be used, or two or more thereof may be used in combination.

Furthermore, these sulfide solid electrolytes may be in the precursor state. When it is deposited as a precursor, it is converted into a solid electrolyte by a treatment such as heat treatment after the deposition.

The form of the solid electrolyte contained in the solid electrolyte layer 22 is not particularly limited, but is granular (meaning that it is solid, and not only spherical, but also columnar, plate-like, flat, scaly, and the like. It is a concept that includes). That is, a granular solid electrolyte (hereinafter, also simply referred to as “granular solid electrolyte”) can be used. The particle size of the granular solid electrolyte is not particularly limited, but at least two kinds of granular solid electrolytes having different particle sizes, that is, a larger diameter granular solid electrolyte and a smaller diameter granular solid electrolyte, can be simultaneously contained. As a result, both the filling property and the smoothness of the solid electrolyte layer 22 can be achieved at the same time. More specifically, it includes a solid electrolyte having a particle size of more than 0.5 μm and 10 μm or less (large diameter solid electrolyte) and a solid electrolyte having a particle size of 1 nm or more and 500 nm or less (small diameter solid electrolyte). Is preferable. When the solid electrolyte has a plate shape or an irregular shape, the length in the longest axial direction is treated as the particle size.

A conductive auxiliary agent is a substance that can be an electron conduction path. Specifically, a powdery substance having conductivity is preferable. The material constituting such a conductive auxiliary agent is not particularly limited, and examples thereof include carbon-based materials (carbon-based materials as conductive auxiliary agents), metals, metal compounds, and the like, and among them, carbon-based materials are preferable. Examples of the carbon-based material include graphite, graphene, carbon black, carbon nanotubes and the like.

When the electrode of the present invention is a positive electrode and contains a conductive auxiliary agent, it may be contained in only one of the active material layer 21 and the solid electrolyte layer 22, but both of these layers may contain the electrode. It is preferably contained.

When the active material layer 21 contains a conductive auxiliary agent, and the total amount of the active material layer 21 is 100% by mass, the content ratio of the conductive auxiliary agent is preferably 0.1% by mass or more and 35% by mass or less. More preferably, it is 1% by mass or more and 25% by mass or less.

Similarly, when the solid electrolyte layer 22 contains a conductive auxiliary agent and the entire solid electrolyte layer 22 is 100% by mass, the content ratio of the conductive auxiliary agent is 0.1% by mass or more and 35% by mass. The following is preferable, and 1% by mass or more and 25% by mass or less is more preferable.

[2] Electrode Manufacturing Method Electrodes of all-solid-state lithium-ion batteries, particularly those having a laminated structure in which an active material layer and a solid electrolyte layer are laminated as described above, have target components (active material, solid electrolyte, etc.). ) (Hereinafter, simply referred to as “target particles”) are preferably deposited while being controlled to a desired thickness. When it is necessary to increase the capacity, it is desirable to increase the amount of active material, but if only the active material is thickly deposited, the ionic conductivity will decrease and the amount of electricity that can be taken out to the outside will decrease. Therefore, it is desired to design an appropriate layer thickness and to have a structure in which an active material layer and a solid electrolyte are laminated according to the design.

According to this production method, each layer of the active material layer and the solid electrolyte layer in the electrode can be formed in the above-mentioned range. Specifically, the thickness of the active material layer can be 0.5 μm or more and 40 μm or less, further can be 1 μm or more and 25 μm or less, and more preferably 4 μm or more and 8 μm or less. Similarly, for example, the thickness D ₂₂ of the solid electrolyte layer 22 can be 0.25 μm or more and 40 μm or less. The thickness (D ₂₂ ) is further preferably 0.25 μm or more and 25 μm or less, more preferably 0.25 μm or more and 8 μm or less, and particularly preferably 0.25 μm or more and 0.5 μm or less.

Further, for example, it may be deposited in substantially a single layer (a very thin layer as a whole even if it is partially multi-layered). Considering ionic conductivity and electron conductivity, it is preferable that the particles can be deposited with a thickness of 1 or more and 3 or less, and more preferably 1 or more and 2 or less of the particles can be deposited. This is because it is considered that the active material layer in the electrode and the solid electrolyte layer can be brought into close contact with each other by depositing thinly, and excellent electrode characteristics can be obtained. That is, the number of layers can be increased within the same electrode thickness, whereby the contact area between the active material and the solid electrolyte can be increased. Therefore, in the present production method, the target particles are deposited by electrophoresis using a dispersion liquid (a liquid containing particles (hereinafter, also simply referred to as “particle-containing liquid”)) in which the target particles are dispersed in a solvent, and a layer is formed. Shape the structure. As a result, it is possible to form a layer in which each target particle is deposited thinner and more accurately than dipping or coating.

(1) Method for manufacturing the first electrode This method for manufacturing the first electrode (hereinafter, also simply referred to as “first manufacturing method”) is carried out on a conductive substrate by electrophoresis in a particle-containing liquid. It is provided with a deposition process for depositing target particles.

The "deposition step" includes a first deposition step of depositing the active material by electrophoresis in a particle-containing liquid (active material-containing liquid) in which the target particle is an active material, and a solid electrolyte and / or a precursor thereof in which the target particle is a solid electrolyte and / or a precursor thereof. It includes a second deposition step of depositing a solid electrolyte or a precursor thereof by electrophoresis in a particle-containing liquid (solid electrolyte-containing liquid) which is a body.

The "precursor of the solid electrolyte" is a solid (particle) that changes into a solid electrolyte by removing the dispersion medium and, if necessary, performing post-treatment such as heating. Here, since the layer formed by the solid electrolyte precursor is also a layer that becomes a solid electrolyte, it may be appropriately referred to as a solid electrolyte layer below.

When the first deposition step is performed after the solid electrolyte layer is formed to further form the active material layer, the poor solvent and aprotonic solvent of the solid electrolyte and / or its precursor is used as the dispersion medium. Will be done. As the active material in such a case, a material to which the above-mentioned ion exchange resin having ions ionized in the poor solvent is attached is used.

Normally, in electrophoresis, the electrophoretic substance dispersed in the dispersion medium is electrophoresed electrically, but the dispersion medium is used so that the electrophoretic substance has a sufficiently strong surface charge in the dispersion medium. , It is common to use a polar solvent with a higher polarity (higher dielectric constant) or a protonic solvent.

Here, the active material and the solid electrolyte or its precursor differ in the solubility in a solvent and the strength of the surface charge in the liquid. For example, active materials are relatively stable to polar solvents, but tend to have a weak surface charge in non-polar solvents. In addition, the solid electrolyte has a greater affinity (solubility) for a polar solvent than the active material. Therefore, when the solid electrolyte layer (including its precursor layer) has already been formed, the solid electrolyte layer may be dissolved when the active material is electrophoresed using a polar solvent as a dispersion medium. ..

Dissolution of such a solid electrolyte layer can be prevented by using a non-polar solvent (a poor solvent of the solid electrolyte or its precursor), which is aprotonic and has a smaller polarity, as the dispersion medium, but the surface charge of the active material is increased. If it is weak, the migration becomes difficult.

In the first production method, such a solvent is used by adhering an ion exchange resin having an ion exchange group that ionizes a counter ion in a poor solvent of a solid electrolyte or a precursor thereof and an aproton solvent to an active material. It is possible to produce an electrode in which both the active material and the solid electrolyte are alternately deposited by electrophoresis.

Therefore, the first deposition step is carried out by electrophoresis using a poor solvent (non-polar solvent, solvent having a low dielectric constant) of the solid electrolyte or its precursor and an aprotonic solvent as a dispersion medium of the active material. This makes it possible to suppress the dissolution of the already produced solid electrolyte layer.

Further, since the active material is in a state where an ion exchange resin having ions that are ionized in the solvent is attached, the surface charge is increased by the action of the ion exchange resin, and a solvent having a weak polarity such as a non-polar solvent is dispersed. Even if it is used as a medium, it can be run well. Therefore, it is possible to both suppress the dissolution of the solid electrolyte layer and deposit the active material by electrophoresis, and it is possible to manufacture an electrode in which the solid electrolyte layer or its precursor layer and the active material layer are laminated. As described above, since any layer can be formed by electrophoresis, it is possible to produce an electrode structure in which the layer thickness of each layer is appropriately controlled.

Here, when all the layers are formed by electrophoresis, first, the first deposition step is carried out, and the first active material layer on which the active material is deposited is formed on the conductive substrate. Will be done. Next, a second deposition step is carried out, and a solid electrolyte or a precursor thereof is deposited on the active material layer formed in the first deposition step to form the first solid electrolyte layer. After that, the first deposition step is carried out again to form the second layer of the active material layer on the solid electrolyte layer. In this way, the first deposition step and the second deposition step are repeatedly executed to form an n-layer active material layer and a solid electrolyte layer. Although each layer is laminated on the conductive base material to form an electrode, either the active material layer or the solid electrolyte layer may be laminated on the conductive surface of the base material. That is, the second deposition step may be carried out first, and then the first deposition step may be carried out.

Further, in the first deposition step carried out before the solid electrolyte layer is formed, since there is no concern that the fixed electrolyte layer is dissolved, the active material is electrophoresed and deposited using a polar solvent or a protic solvent. Is also good.

Here, the "base material" has a conductive surface, and functions as a support for a deposited layer of the obtained particles (hereinafter, also simply referred to as a "deposited layer").

The material of the base material is not particularly limited, and a conductive material capable of forming a conductive surface can be widely used. Examples of the conductive material include gold, platinum, indium, copper, zinc, nickel, tin, aluminum, stainless steel, alloys of these metals, and a conductive compound (ITO) containing these metals. Only one of these may be used, or two or more thereof may be used in combination. When two or more types are used together, they can be stacked and used.

The form of the conductive material is not particularly limited, and for example, a plate-like body, a foil-like body, a mesh-like body, or the like can be appropriately used. Only one of these may be used, or two or more thereof may be used in combination.

For example, as the base material, the plate-like body made of the above-mentioned conductive material can be used as it is. Further, a composite in which the surface of a plate-like body made of a non-conductive material (resin or the like) is coated with the foil-like body made of the above-mentioned conductive material can be used as a base material as a whole.

This base material can be used as it is as a current collector in an all-solid-state lithium-ion battery.

The state of the dispersion liquid (particle-containing liquid) in which the target particles are dispersed in the dispersion medium is not particularly limited, and may be any of suspension (suspension), emulsion, colloidal liquid and the like.

The particles that are the dispersoids in this dispersion are particles that have been adjusted so that they can be deposited by electrophoresis. The material constituting the particles is not particularly limited, and various components blended in the electrode can be granulated so as to be electrophoretic and used as appropriate. Specific examples thereof include the above-mentioned active material, particles composed of a solid electrolyte or a precursor thereof, a conductive auxiliary agent, and the like. Only one of these may be used, or two or more thereof may be used in combination.

The shape of the particles is not particularly limited, and examples thereof include a substantially spherical shape, a granule shape (a shape in which smaller particles are gathered together), a lump shape, a flake shape (scale shape), a needle shape, an indefinite shape, a wire shape, a tube shape, and the like. .. Only one of these may be used, or two or more thereof may be used in combination.

The particle size (maximum length) of the particles is not particularly limited, but is usually 7 μm or less. Electrophoresis may be performed on particles having a particle size of more than 7 μm using an applied voltage having an asymmetric signal, but it is difficult to obtain the effect of using the asymmetric signal for particles having such a large particle size. That is, for example, it is possible to form a monolayer film relatively easily by using only a DC voltage.

On the other hand, for particles having a particle size of 7 μm or less (particularly 4 μm or less), as the particle size becomes smaller, electrophoresis using only DC voltage or normal AC voltage (that is, positive electrode side and negative electrode side) Electrophoresis using a voltage having a signal having a symmetrical waveform may make it difficult to form a monolayer film. In that case, by using the asymmetric signal, it becomes possible to obtain a laminate in which the particles are relatively uniformly arranged (the particles do not overlap each other) while increasing the deposition rate of the particles.

For this reason, the particles of the particle-containing liquid preferably contain particles having a particle size of 7 μm or less, more preferably 4 μm or less, and particularly preferably 1 μm or less. The lower limit of the particle size is not particularly limited, but can be, for example, 50 nm.

On the other hand, the dispersion medium constituting the particle-containing liquid is aprotonic, does not have an influence such as dissolving the particles in the dispersion medium or the already deposited layer, and the particles in the dispersion medium (in the case of an active material, in the case of an active material). It satisfies the requirement of having an affinity for the attached ion exchange resin), and various solvents can be used.

Specifically, examples of such a solvent include linear or branched aliphatic hydrocarbons, aliphatic unsaturated hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and halides thereof (halogenated hydrocarbons). ) And other non-polar solvents. Examples of aliphatic hydrocarbons or halogenated hydrocarbons include pentadecane, hexane, heptane, octane, isooctane, decane, undecane, dodecane, isododecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, chloroform, methylene chloride and the like. Be done. Examples of the aliphatic unsaturated hydrocarbon include dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, and the like. Examples of aromatic hydrocarbons include toluene, xylene, ethylbenzene, cumene and the like. In addition, as the alicyclic hydrocarbon, an alicyclic ether such as cycloalkane (cyclopentane, cyclohexane, cyclooctane, etc.) having 3 or more carbon atoms or tetrahydrofuran can also be used. Examples of ethers include diethyl ether and dimethoxyethane, and examples of esters include ethyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate and the like. One or a combination of two or more of these can be used.

Here, a non-polar solvent (solvent having a small polarity) is preferably selected as the dispersion medium. The non-polar solvent is a low-polarity solvent classified as hydrophobic. Solid electrolytes and their precursors are poor solvents due to their low solubility in non-polar solvents. As an index of the polarity of the solvent, the dielectric constant of the solvent can be mentioned. In this production method, the solvent is selected with the dielectric constant of 15 or less as an index.

Further, as long as the above requirements are satisfied, a solvent having a dielectric constant of more than 15 may be mixed as long as the solid electrolyte or its precursor is not dissolved. Furthermore, since the affinity between the active material and the solid electrolyte (or its precursor) is different, different solvents may be used as the dispersion medium for the active material and the solid electrolyte and the like.

When the target particle is an active material, a solvent having an affinity for the active material is selected as the dispersion medium, and methylene chloride, dimethoxyethane, and tetrahydrofuran are preferably selected. When the target substance is a solid electrolyte or a precursor thereof, a substance having an affinity for these is selected as the dispersion medium, and ethyl propionate and ethyl acetate are preferably selected.

The concentration of the particles contained in the particle-containing liquid is not particularly limited, but when the total of the particles (dispersant) and the dispersion medium is 100% by mass, the content ratio of the particles is 0.1% by mass or more and 30% by mass. It can be less than or equal to%. This ratio is preferably 0.5% by mass or more and 25% by mass or less, more preferably 1% by mass or more and 20% by mass or less, and particularly preferably 1% by mass or more and 15% by mass or less.

In the first production method, each target particle is electrophoresed using a DC voltage. The current density during electrophoresis is not limited, but when an active material is electrophoresed, a current density of 10 ^{μAcm -2 to 1 mAcm -2} can be applied, preferably in the vicinity of ^{20 μAcm -2 to} 500 μAcm ^-2. It is desirable to run, preferably 30 μAcm- ^{2 to} 300 μAcm- ² , and more preferably 30 μAcm- ^{2 to} 200 μAcm- ² . When migrating a solid electrolyte, it is preferable to run in the vicinity of ^{several μAcm-2 , preferably 1 μAcm-2 to} 50 μAcm- ² , and more preferably 3 μAcm- ^{2 to} 20 μAcm- ² .

Here, when electrophoresis is performed using a DC voltage, the target particles may be deposited in an extremely short time, and a thick deposited layer may be formed. That is, a deposited layer in which a plurality of target particles are stacked is formed instead of a deposited layer in which the target particles are laminated in a substantially single layer. On the other hand, by lowering the current density of the applied DC voltage, it is possible to suppress the deposition rate and make the film thickness control easier (stacking in a substantially single layer), but the surface of the obtained deposition layer. The roughness becomes large. That is, in electrophoresis using a DC voltage, there is a trade-off relationship between the film thickness of the obtained deposited layer and the surface roughness, and the film is a substantially single layer having both the film thickness and the surface roughness and the surface roughness is small. It can be difficult to obtain a sedimentary layer.

Therefore, the present inventors tried to use an AC voltage in electrophoresis. As a result, it was found that the surface roughness of the obtained sedimentary layer can be suppressed while reducing the deposition rate. However, it has been found that the use of AC voltage reduces the deposition rate excessively. Then, it was found that there is a problem that a film thickness higher than a certain level cannot be formed even if the precipitation time is extended.

Therefore, the present inventors have further attempted to use both a DC voltage and an AC voltage in combination. As a result, it was conceived that the deposition rate can be controlled within a practical range, the surface roughness can be suppressed, and a deposition layer having a desired film thickness can be obtained (Japanese Patent Application No. 2015-242721. However, at the time of filing the application of the present application). Not known in). According to this method, the combined use of the DC voltage and the AC voltage causes a bias to be applied to the AC signal having a symmetric waveform on the positive side and the negative side, and as a result, the positive side and the negative side are asymmetric. A signal having a different waveform (hereinafter, also simply referred to as “asymmetric waveform”) (hereinafter, also simply referred to as “asymmetric signal”) is formed (see FIGS. 2 to 6). In this way, by utilizing the applied voltage having an asymmetric signal, as described above, it is possible to suppress the surface roughness and obtain a deposited layer having a desired film thickness while controlling the deposition rate within a practical range. I found that I could do it.

Based on the above findings, in this manufacturing method, not only the method of applying a DC voltage to electrophores the target substance, but also the method of using a DC voltage and an AC voltage in combination and applying a voltage having an asymmetric signal is used. Each layer may be formed.

In electrophoresis using such an asymmetric waveform, the stronger the polarity of the dispersion medium and the smaller the particles, the better the followability of the particles with respect to the applied voltage, and the easier it is to control the deposition state. When the polarity of the dispersion medium is weakened, the followability of the electrophoresed particles to the applied voltage is lowered, but it works usefully when the electrophoresed particles are fine. Therefore, the operator can select whether to use a DC voltage or a superposed voltage of DC and AC based on the polarity of the dispersion medium and the particle size of the electrophoresed particles.

Having an asymmetric waveform between the positive electrode side and the negative electrode side means that the signal waveform on the positive electrode side with 0V as the boundary and the signal waveform on the negative electrode side with 0V as the boundary are not symmetrical. .. That is, specific examples of the asymmetric signal include (1) a signal in which the absolute value of the peak differs between the positive electrode side and the negative electrode side, and (2) a signal in which the application time differs between the positive electrode side and the negative electrode side. As a matter of course, a signal in which the absolute value of the peak differs between the positive electrode side and the negative electrode side and the application time differs between the positive electrode side and the negative electrode side is also included.

Such an asymmetric signal may be formed in any way. That is, the asymmetric signal may be appropriately designed, or may be formed by superimposing a DC voltage and an AC voltage. When the DC voltage and the AC voltage are superimposed, the signal of one kind of frequency may be used as the signal of the AC voltage, or the signal of two kinds of different frequencies may be used in combination.

As the asymmetric signal, for example, the form of the signal shown in FIGS. 2 to 6 can be mentioned. Only one type of these asymmetric signals may be used, or two or more types may be used in combination.

Of the above, in the asymmetric signal of FIG. 2, the positive electrode side peak absolute value (V ₊ ) and the negative electrode side peak absolute value (V ₋ ) are different, and the positive electrode side application time (T ₊ ) and the negative electrode side application time (T _{−) are different.} ) Is the same as an asymmetric signal formed by a triangular wave. Such an asymmetric signal can be formed, for example, by biasing a triangular wave symmetric signal (AC signal) toward the positive electrode side. That is, it can be formed by superimposing an AC voltage and a DC voltage.

In the asymmetric signal of FIG. 3, the positive electrode side peak absolute value (V ₊ ) and the negative electrode side peak absolute value (V ₋ ) are different, and the positive electrode side application time (T ₊ ) and the negative electrode side application time (T ₋ ) are different. It is an asymmetric signal formed by a square wave. _{This square wave has a signal form in which a constant peak absolute value (V +} or V ₋ ) is maintained for a certain period of time on both the positive electrode side and the negative electrode side.

In the asymmetric signal of FIG. 4, the positive electrode side peak absolute value (V ₊ ) and the negative electrode side peak absolute value (V ₋ ) are different, and the positive electrode side application time (T ₊ ) and the negative electrode side application time (T ₋ ) are different. It is an asymmetric signal formed by a triangular wave.

In the asymmetric signal of FIG. 5, the positive electrode side peak absolute value (V ₊ ) and the negative electrode side peak absolute value (V ₋ ) are different, and the positive electrode side application time (T ₊ ) and the negative electrode side application time (T ₋ ) are different. It is an asymmetric signal represented by a parabola.

In the asymmetric signal of FIG. 6, the positive electrode side peak absolute value (V ₊ ) and the negative electrode side peak absolute value (V ₋ ) are different, and the positive electrode side application time (T ₊ ) and the negative electrode side application time (T ₋ ) are different. It is an asymmetric signal formed by a square wave. This rectangular wave has a signal form in which the applied voltage changes with time on both the positive electrode side and the negative electrode side, and at the same time, it instantly switches to a reverse electric field after passing through the peak top.

In the electrode manufacturing method of the present invention, if the target particles can be deposited better when these asymmetric signals are used for electrophoresis using a DC voltage, the asymmetric signals may be used as appropriate. Various asymmetric signals can be used.

For the asymmetric signal, the absolute value of the peak on the positive electrode side (amplitude from 0V to the peak end) is V _+, and the absolute value of the peak on the negative electrode side (amplitude from 0V to the peak end) is V ₋ (Fig. 2 to FIG. 6), the ratio (V ₊ / V ₋ ) is preferably 0.02 ≦ V ₊ / V ₋ ≦ 50. In this range, the effect of using signals having different absolute peak values on the positive electrode side and the negative electrode side can be obtained particularly well.

This ratio (V ₊ / V _{− ) is more preferably 1 <V +} / V ₋ ≦ 50, further preferably 1.01 ≦ V ₊ / V ₋ ≦ 30, especially when the action of migrating to the positive electrode side is strengthened. , 1.3 ≤ V ₊ / V ₋ ≤ 10 is particularly preferable, and 1.5 ≤ V ₊ / V ₋ ≤ 5 is particularly preferable.

On the contrary, when the action of migrating to the negative electrode side is particularly strengthened, 0.02 ≦ V ₊ / V ₋ <1 is more preferable, 0.03 ≦ V ₊ / V ₋ ≦ 0.99 is further preferable, and 0.1. ≤V ₊ / V ₋ ≤ 0.7 is particularly preferable, and 0.2 ≤ V ₊ / V ₋ ≤ 0.5 is particularly preferable.

Further, the application time on the positive electrode side (time indicating the amplitude toward the positive electrode side with reference to 0V) is defined as T _+, and the application time on the negative electrode side (time indicating the amplitude toward the negative electrode side with reference to 0V) is defined as T +. Assuming T ₋ (see FIGS. 2 to 6), the ratio (T ₊ / T ₋ ) is preferably 0.02 ≦ T ₊ / T ₋ ≦ 50. In this range, the effect of using signals having different application times on the positive electrode side and the negative electrode side can be obtained particularly well.

This ratio (T ₊ / T _{− ) is more preferably 1 <T +} / T ₋ ≦ 50, further preferably 1.01 ≦ T ₊ / T ₋ ≦ 30, especially when the action of migrating to the positive electrode side is strengthened. , 1.3 ≤ T ₊ / T ₋ ≤ 10 is particularly preferable, and 1.5 ≤ T ₊ / T ₋ ≤ 5 is particularly preferable.

On the contrary, when the action of migrating to the negative electrode side is particularly strengthened, 0.02 ≦ T ₊ / T ₋ <1 is more preferable, 0.03 ≦ T ₊ / T ₋ ≦ 0.99 is further preferable, and 0.1. ≤T ₊ / T ₋ ≤ 0.7 is particularly preferable, and 0.2 ≤ T ₊ / T ₋ ≤ 0.5 is particularly preferable.

Further, the ratio {(V ₊ × T ₊ ) / (V ₋ × T ₋ )} may also be 0.02 ≦ {(V ₊ × T ₊ ) / (V ₋ × T ₋ )} ≦ 50. preferable.

This ratio {(V ₊ × T ₊ ) / (V ₋ × T _{− )} is 1 <{(V +} × T ₊ ) / (V ₋ × T ₋ ), especially when the action of migrating to the positive electrode side is strengthened. )} ≦ 50 is more preferable, 1.01 ≦ {(V ₊ × T ₊ ) / (V ₋ × T ₋ )} ≦ 30 is more preferable, and 1.3 ≦ {(V ₊ × T ₊ ) / (V) ₋ × T ₋ )} ≦ 10 is particularly preferable, and 1.5 ≦ {(V ₊ × T ₊ ) / (V ₋ × T ₋ )} ≦ 5 is particularly preferable.

On the contrary, when the action of migrating to the negative electrode side is particularly strengthened, 0.02 ≦ {(V ₊ × T ₊ ) / (V ₋ × T ₋ )} <1 is more preferable, and 0.03 ≦ {(V _+). × T ₊ ) / (V ₋ × T ₋ )} ≦ 0.99 is more preferable, and 0.1 ≦ {(V ₊ × T ₊ ) / (V ₋ × T ₋ )} ≦ 0.7 is particularly preferable. 0.2 ≦ {(V ₊ × T ₊ ) / (V ₋ × T ₋ )} ≦ 0.5 is particularly preferable.

As described above, when only the DC voltage is used, the deposition rate is high when the current density is high (for example, 1 mA / cm ^{2 or more in the case of an active material and several 100 μA / cm 2} or more in the case of a solid electrolyte). The film thickness of the particle deposition layer (for example, the active material layer or the solid electrolyte layer) to be formed becomes excessively thick in a short time, and the film thickness may not be controlled. On the other hand, if the current density is small, the deposition rate can be reduced, but there may be a problem that the surface roughness of the obtained particle deposition layer becomes large.

In such a case, when the particle deposition layer having a large surface roughness is observed, the particles are laminated to each other. Where a monolayer in which particles are deposited in a single layer on a desired region of a conductive surface is an ideal particle deposition layer, a particle deposition layer having a large surface roughness is a particle deposition in a certain part of the conductive surface. However, particles are deposited in two or more layers in other places, and as a result of the large variation in the deposition thickness, the surface roughness tends to increase.

That is, for example, when six particles 52 are deposited on the conductive surface of the base material 51, when the particles 52 are laminated with each other as illustrated in FIG. 8, the particles 52 are deposited with each other to form a film. There will be places where the thickness is increased and places where the particles 52 are not deposited at all, and the surface roughness of the obtained deposited layer will be large. On the other hand, as illustrated in FIG. 7, for example, if all the particles 52 can be deposited in one layer, even if the number of deposited particles is the same as in the case of FIG. 8, FIG. In FIG. 7, a sedimentary layer having a smaller surface roughness can be obtained as compared with the sedimentary layer. Then, if these operations can be repeated, as shown in FIG. 9, different types of particles (particles 521 and particles 522) can be regularly deposited to increase the contact area with each other.

In this regard, when an asymmetric signal is used, it is possible to obtain a particle deposition layer having a small surface roughness and a sufficiently small deposition thickness with respect to the particle size of the particles. That is, an ideal particle deposition as illustrated in FIGS. 7 and 9 can be obtained. The reason why the particle distribution can be controlled by using such an asymmetric signal is not clear. Furthermore, it is not clear why the effect of using an asymmetric signal appears for particles having a smaller particle size. However, from the background of the experiments so far, it is considered that the mass difference (inertia) of the moving particles has an influence.

Then, when the time for strengthening the action of the electric field flowing to the substrate side (for example, the application time on the positive electrode side) becomes long, the amount of deposition becomes excessively large (accumulation beyond being a substantially single-layer film). Since there is a possibility, it is preferable to suppress the time for strengthening the action of the electric field flowing to the substrate side to a short time as described above. That is, it is preferable that the migration action on the substrate side is strong (the absolute value of the peak is large) and short (the application time is short). In addition, it is considered that the deposited particles can be appropriately dispersed by making the electric field in the opposite direction weak (small absolute value of the peak) and acting for a long time (long application time).

For the reasons described above, the particles can be deposited only once by electrophoresis, but can be divided into a plurality of times as needed. In other words, in the first deposition step (second deposition step), one set of a plurality of electrophoresiss can be combined to form one active material layer or a solid electrolyte layer. In particular, when a plurality of types of particles having different particle sizes (that is, different masses) are used, by using an asymmetric signal suitable for each particle, it is possible to obtain a substantially single layer with better controllability and to obtain a surface roughness. A small particle deposition layer can be obtained. Further, the electrophoresis may be performed by combining the asymmetric signal and the voltage application of only the DC voltage.

Specifically, there is a case where a first particle-containing liquid containing large-diameter particles and a second particle-containing liquid containing small-diameter particles are used. That is, each particle can be contained in a different particle-containing liquid and deposited using an asymmetric signal suitable for each electrophoresis. In particular, electrophoresis is performed in the first particle-containing liquid to deposit large-diameter particles, and then electrophoresis is performed in the second particle-containing liquid to deposit small-diameter particles and large-diameter particles. Small-diameter particles can be deposited so as to fill the gaps formed between the particles.

In this way, particles having different particle size groups are dispersed in different particle-containing liquids, electrophoresis is performed with a particle-containing liquid having a large particle size, and then electrophoresis is performed with a particle-containing liquid having a gradually smaller particle size. As a result, a dense particle deposition layer with excellent surface smoothness can be formed.

Further, by controlling the frequency of the applied voltage according to the particle size, a more monolayered deposit can be obtained. That is, it is possible to positively select a frequency that makes it easier to form a single layer. Specifically, an appropriate frequency is searched in advance according to the particle size to be deposited and the particle size distribution thereof, and a voltage is applied (electrophores) using that frequency to suppress the deposition of the second layer or higher. , The deposition area of only the first layer (single layer) can be selectively increased.

The frequency of the applied voltage can be, for example, 5 Hz or more and 13 Hz or less, preferably 6 Hz or more and 13 Hz or less, more preferably 7 Hz or more and 12 Hz or less, and particularly preferably 7 Hz or more and 11 Hz or less. It can be used for particles of any particle size at this frequency, but is particularly suitable for particles having an average particle size of 0.5 μm or more and 7 μm or less (particularly 0.7 μm or more and 6 μm or less).

(2) Method for manufacturing the second electrode In this method for manufacturing the second electrode (hereinafter, also simply referred to as “second manufacturing method”), in addition to the above-mentioned first manufacturing method, an ion exchange resin is attached to the active material. It is configured to include a pretreatment step to make it. In this pretreatment step, an ion exchange reaction is carried out according to a conventional method. Specifically, after dissolving a predetermined amount of the ion exchange resin, a predetermined amount of the active material is added and stirred to attach the ion exchange resin to the active material. Then, the active material is collected and washed. Next, the recovered active material is added to the solution in which the salt is dissolved, and the counterion of the ion exchange group of the ion exchange resin attached to the active material is replaced with the salt ion by an ion exchange reaction. If the counterion of the ion exchange group is a cation, it is replaced with a salt cation, and if the counterion of the ion exchange group is an anion, it is replaced with a salt anion. A polar solvent such as water or alcohol is preferably used as the solvent for dissolving the ion exchange resin or the salt.

For example, when the ion exchange group of the ion exchange resin is a sulfonic acid group and the salt is an organic onium salt, the proton of the sulfonic acid group is replaced with the cation (cation) of the organic onium salt. As a result, the ion exchange group of the ion exchange resin becomes a salt form (salt type).

As the pair ion of the ion exchange group, the initial pair ion (H ⁺ or OH ⁻ ) may be used as the target pair ion (first pair ion) in one ion exchange reaction, and may be used as another pair ion. After the exchange, further ion exchange may be performed to obtain the desired pair ion (first pair ion). Further, the ion exchange resin of the starting material may be a salt type resin obtained by ion exchange.

Here, when the ion exchange resin is a polymer having a unit derived from styrene and a unit derived from olefin in the main chain, the portion of the main chain has an affinity for a solvent having low polarity such as a non-polar solvent. Have. Therefore, when a low-polarity solvent such as a non-polar solvent is used as the dispersion medium of the active material-containing liquid, it acts in the direction of stably dispersing the active material in the dispersion medium. It is also presumed to act to promote the ionization of the counterion of the ion exchange group.

When the ion exchange group is a sulfonic acid group (or a sulfonic acid-derived group or a sulfonate-type group) which is a strongly acidic group, the proton and the other cation of interest are relatively easily ionized. Can be exchanged. Therefore, an ion exchange resin substituted with cations of an organic onium salt (cation exchange) can be easily obtained. At least a part of the ion exchange group can be made into an arbitrary counterion by the ion exchange reaction, and the structure can be changed to a structure in which the counterion is more easily ionized than the original ion exchange resin. Thereby, when the first deposition step is carried out, the counterion can be easily ionized from the ion exchange group in the non-polar solvent, and the charge given to the active material can be strengthened.

Examples of such organic onium salts include bromonium salt, iodonium salt, oxonium salt, sulfonium salt, arsonium salt, ammonium salt (quaternary), ammonium fluoride (quaternary), and ammonium chloride (quaternary) as described above. ), Ammonium bromide (quaternary), ammonium iodide (quaternary), ammonium hydroxide (quaternary), ammonium polyhalide, phosphonium salt and the like. In particular, from the viewpoint of dissolution stability, it is preferable to use a quaternary salt, and a quaternary ammonium salt and a quaternary phosphonium salt are more preferable. As a result, in the first deposition step described above, when the active material is laminated by electrophoresis, the counterions ionized from the ion exchange group in the non-polar solvent are stabilized in the solvent, so that the charge given to the active material is applied. Can be strengthened, the recombination of counterions can be suppressed, and the dispersibility and migration of the active material in the solvent can be maintained well. Therefore, the electrophoresis can be performed more stably.

Here, in the second production method, the ion exchange group is a cation exchange group, and a salt-type product having a cation of an organic onium salt as a counterion has been described. However, the ion exchange group is an anion exchange group. It may be. In such cases, a strongly basic ion exchange group is suitable. Further, in order to obtain the same action as in the case of the above-mentioned cation exchange group, it is desirable that the ion exchange group is in the salt type, and the anion of the lithium salt is desirable as the counter ion in such a case. In addition to the anion of the lithium salt, it may be ion-exchanged with the anion of the anionic surfactant to form a counterion.

Then, after the completion of the pretreatment step, the above-mentioned first deposition step is carried out using the active material treated in the pretreatment step, and an electrode is produced by the same step as the first manufacturing method.

(3) Method for manufacturing the third electrode In the method for manufacturing the third electrode (hereinafter, also simply referred to as “third manufacturing method”), an active material layer containing an active material as a main component and a solid electrolyte or a precursor thereof are used. A method for producing an electrode including a solid electrolyte layer containing a body as a main component, wherein the solid electrolyte layer is formed of a sulfide solid electrolyte or a precursor thereof. The active material-containing liquid comprises a first deposition step of depositing the active material to form an active material layer by electrophoresis in the active material-containing liquid, and the active material-containing liquid contains methylene chloride as a dispersion medium. Further, as the active material contained in the active material-containing liquid, one to which the above-mentioned ion exchange resin having a counterion (first counterion) ionized in a dispersion medium (methylene chloride) is attached is used.

Further, in the third production method, as a pre-step or a post-step of the first deposition step, the solid electrolyte and / or its precursor is obtained by electrophoresis in a solid electrolyte-containing liquid containing the solid electrolyte and / or its precursor. It is provided with a second deposition step of depositing adjacent to the active material layer to form a solid electrolyte layer or a precursor layer thereof. At this time, the solid electrolyte is a sulfide solid electrolyte or a precursor thereof.

In this case, the dispersion medium of the solid electrolyte-containing liquid is not particularly limited, but a saturated fatty acid ester compound is preferable. By using a saturated fatty acid ester compound as a dispersion medium, a sulfide solid electrolyte can be used as a particle, particularly as a solid electrolyte. Examples of the saturated fatty acid ester compound include methyl propionate, ethyl propionate, propyl propionate, butyl propionate and the like. Only one of these may be used, or two or more thereof may be used in combination. Of these, ethyl propionate is particularly preferred.

Further, also in the third manufacturing method, an asymmetric signal can be used in electrophoresis as described above.

Each of the above descriptions in the third manufacturing method has already been described in the first manufacturing method.

[3] Battery Manufacturing Method The all-solid-state lithium-ion battery (1) of the present invention is characterized by including the electrode (2) according to the present invention.

That is, the all-solid-state lithium-ion battery (1) has a structure in which the solid electrolyte body (3) is arranged between the pair of electrodes (2a, 2b). Of these, one of the pair of electrodes functions as a positive electrode and the other functions as a negative electrode. Each electrode is as described above.

Further, the solid electrolyte body (3) is a Li ion conductor containing the solid electrolyte. The shape, size, etc. are not particularly limited and may be appropriate. Further, as the solid electrolyte constituting the solid electrolyte body (3), the above-mentioned solid electrolyte that can be used for the electrode (2) can be used as it is. However, it is preferable that the solid electrolyte contained in the electrode (2) and the solid electrolyte contained in the solid electrolyte body (3) are the same.

In addition to the above, the all-solid-state lithium-ion battery (1) of the present invention may be provided with a known configuration, for example, a separator or the like, if necessary.

Hereinafter, in addition to the electrode of the present invention and the method for manufacturing the electrode, the concepts of various inventions included in the various embodiments described above are shown.

The electrode used in an all-solid-state lithium-ion battery having a structure in which a solid electrolyte is arranged between a pair of electrodes, and is an active material layer containing an active material as a main component and a solid containing a solid electrolyte as a main component. An electrode A1 comprising an electrolyte layer.

According to the electrode A1, an active material layer containing an active material as a main component and a solid electrolyte layer containing a solid electrolyte as a main component are provided. That is, it is an electrode formed by controlling the distribution of each component of the active material and the solid electrolyte in a layered manner. With this configuration, any layer structure can be introduced into the active material layer. Therefore, it is possible to realize a structure in which the movement path of ions from the active material layer to the solid electrolyte layer is designed in advance.

If each layer of the electrode A1 is formed by electrophoresis, each layer can be formed while controlling the layer thickness, but it is not always necessary to form each layer by electrophoresis, and each layer is formed by dipping or coating as appropriate. It may be a thing. Further, it may be formed by combining such a method and electrophoresis.

In the electrode A1, the active material layer is a resin having an ion exchange group, and all or a part of the ion exchange group is ionized in a poor solvent and an aprotonic solvent of the solid electrolyte or a precursor thereof. The electrode A2 is characterized in that the solid electrolyte layer is formed thinner than the active material layer because it contains an ion exchange resin in which counter ions are ion-bonded.

According to the electrode A2, since the solid electrolyte layer is formed thinner than the active material layer, the filling amount of the active material in the electrode can be increased and the battery capacity can be improved.

In the electrode A1 or A2, the electrode A3 is characterized in that both the active material layer and the solid electrolyte layer contain a conductive auxiliary agent. Generally, the electrode is formed on a conductive current collector in order to take out the electrons generated inside the electrode to the outside. Therefore, since each layer in the electrode contains a conductive auxiliary agent, the electrons generated inside the electrode can be smoothly and efficiently conducted to the current collector.

The first deposition step of depositing the active material to form the active material layer by electrophoresis in the active material-containing liquid containing the active material, and the solid electrolyte-containing liquid containing the solid electrolyte and / or its precursor. A second deposition step of depositing the solid electrolyte and / or its precursor by electrophoresis in the medium to form a solid electrolyte layer or a precursor layer thereof adjacent to the active material layer formed in the first deposition step. In the first deposition step, when the active material layer is formed after the solid electrolyte layer is formed, a poor solvent and an aprotonic solvent of the solid electrolyte or its precursor are used as a dispersion medium. In the active material-containing liquid, the active material is electrophoresed in a state where an ion exchange resin having ions to be ionized in the dispersion medium is attached, and the voltage to be applied in the electrophoresis in the second deposition step is performed. The electrode manufacturing method B1 characterized in that a signal having an asymmetric waveform on the positive electrode side and the negative electrode side is used as the signal.

In the electrode manufacturing method B2, the electrode manufacturing method B3 is characterized in that the signal is a signal in which the absolute value of the peak differs between the positive electrode side and the negative electrode side.

In the electrode manufacturing method B2 or B3, the electrode manufacturing method B4 is characterized in that the signal is a signal in which the application time differs between the positive electrode side and the negative electrode side.

According to any of the electrode manufacturing methods B1 to B4, the movement of particles in the liquid can be controlled to a higher degree during electrophoresis.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
[1] Example 1
<1> Preparation of active material-containing liquid (dispersion liquid) As a cation exchange resin, a polystyrene-block-poly (ethylene-ran-butylene) -block-polystyrene sulfonic acid solution (manufactured by Sigma-Aldrich) represented by the following formula (1) , Solvent composition 1,2-dichloroethane 5-10%, 1-propanol 80-90%, THF 3-10%) was neutralized by dropping 0.1 M sodium hydroxide, and precipitated as a sodium salt. After that, centrifugation was performed, the upper layer of the obtained dispersion was removed, the lower layer was recovered, and ion-exchanged water was added to the precipitate to prepare an aqueous solution of an ion-exchange resin as a sodium salt.

Next, in this aqueous solution, as a granular active material, _{a Li-containing double oxide powder represented by Li (Ni x} Mn _y Co _z ) O ₂ (hereinafter, may be simply abbreviated as “NMC powder”), Those having an average particle size of 5 μm were added and dispersed for 30 minutes using an ultrasonic cleaner. Then, the dispersion liquid was centrifuged, and the upper layer of the obtained separation liquid was removed to recover the lower layer. Ion-exchanged water was added to the recovered product, dispersed again with an ultrasonic cleaner, and then washed by repeating the process of recovering by centrifugation five times to remove excess ion-exchange resin.

Subsequently, as an organic onium salt, tetraphenylphosphonium bromide (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added and dissolved in the dispersion until precipitation was formed from the NMC-ion exchange resin dispersion, and the ion exchange reaction carried out earlier was carried out. The sodium ion introduced into the ion exchange resin was replaced with a phosphonium cation. As a result, the counterion of the ion exchange group (sulfonic acid group) of the ion exchange resin adhering to the active material is in the form of a salt that becomes a phosphonium cation.

Then, the active material was recovered from the suspension by centrifugation, washed with ion-exchanged water, and then vacuum dried at 100 ° C. for 6 hours. 1.33 g of the dried active material was added to 50 ml of dehydrated methylene chloride, and dispersion treatment was carried out for 30 minutes with an ultrasonic cleaner to obtain an active material-containing liquid having a solid concentration of 2% by mass.

<2> Preparation of solid electrolyte-containing liquid (dispersion liquid) Lithium sulfide powder and diphosphorus pentasulfide powder were weighed and mixed in an agate mortar so that the molar ratio was 3: 1. The obtained mixture, ethyl propionate, and zirconia balls (diameter 4 mm) are put into a resin container, shaken at a temperature of 24 ° C., an amplitude of about 1 cm, and about 1500 times / minute, and contacted with each other. It was reacted. After 24 hours, the zirconia balls were removed from the resin container, and the solid electrolyte-containing liquid was a dispersion (suspension, solid content concentration 1.1% by mass) in which the precursor of the solid electrolyte (average particle size 1 μm) was dispersed. Got Although this dispersion liquid is a dispersion of a solid electrolyte precursor, it is referred to as a solid electrolyte-containing liquid for the sake of simplicity.

Incidentally, lithium _(Li 2 S) sulfide powder, Ltd. Mitsuwa Kagaku, purity 99%, with an average particle size of 53 .mu.m. Further, phosphorus pentasulfide _(P 2 _{S 5)} powder, Sigma-Aldrich Corp., purity of 99%, was used an average particle size 100 [mu] m.

<3> Electrophoresis The active material-containing liquid obtained in <1> above was put into an electrophoresis tank, and positive and negative electrodes were opposed to each other at intervals of 5 mm in the active material-containing liquid. For the positive electrode and the negative electrode, a base material (ITO substrate) having a conductive surface made of ITO (indium tin oxide) was used.

Then, electrophoresis was performed by applying direct current between the positive electrode and the negative electrode at a current density of ^{30 μA cm-2} for 15 seconds, 30 seconds, and 45 seconds. The positive electrodes (cathodes) that had passed the above migration time were each pulled up from the migration tank and then air-dried. As a result, an active material layer formed on the conductive surface of the ITO substrate was obtained.

Further, the solid electrolyte-containing liquid obtained in <2> above was put into a migration tank, and the positive electrode and the negative electrode were opposed to each other in the solid electrolyte-containing liquid at intervals of 5 mm. For the positive electrode and the negative electrode, a base material (ITO substrate) having a conductive surface made of ITO (indium tin oxide) was used. Then, a direct current was applied between the positive electrode and the negative electrode at a current density of 5.0 μA cm- ² for 15 seconds, 30 seconds, and 45 seconds to perform electrophoresis of the solid electrolyte precursor. The negative electrodes that had passed the above migration time were each pulled up from the migration tank and then air-dried. As a result, a solid electrolyte layer formed on the conductive surface of the ITO substrate was obtained.

The layer thicknesses of the active material layer and the solid electrolyte layer obtained above were calculated based on the weight of the deposit. Specifically, the deposited weight was calculated from the difference in the weight of the ITO substrate before and after electrophoresis, and the deposited area and the specific gravity were converted into the layer thickness. The results are shown in FIG.

FIG. 10 is a diagram showing the relationship between the deposition weight of the precursors of NMC powder and the solid electrolyte and the migration time. The horizontal axis is the migration time (seconds), and the vertical axis is the deposition weight per square centimeter (mg). In FIG. 10, the black-painted squares indicate the amount of NMC powder deposited, and the white triangles indicate the amount of solid electrolyte precursor deposited. In addition, the numerical values in parentheses indicate the layer thickness converted from the accumulated weight.

As can be seen from FIG. 10, it has been shown that the active material layer and the solid electrolyte layer each have a thicker layer thickness depending on the electrophoresis time, and the layer thickness can be appropriately controlled by the electrophoresis time. It became clear.

[2] Example 2 (Lamination of active material layer and solid electrolyte layer)

An active material-containing liquid (dispersion liquid, solid content concentration 2% by mass) was prepared in the same manner as in <1> of Example 1, and further, a solid electrolyte-containing liquid (dispersion) was prepared in the same manner as in <2> of Example 1. Liquid, solid content concentration 1.1% by mass) was obtained.

The active material-containing liquid obtained above was put into the electrophoresis tank, and the positive electrode and the negative electrode were opposed to each other in the active material-containing liquid at intervals of 5 mm. For the positive electrode and the negative electrode, a base material (ITO substrate) having a conductive surface made of ITO (indium tin oxide) was used. Then, a direct current was applied between the positive electrode and the negative electrode at a current density of 30 μA cm- ² for 15 seconds to perform electrophoresis. Then, after pulling up the positive electrode (cathode) from the electrophoresis tank, it was naturally dried to obtain an active material layer formed on the conductive surface of the ITO substrate.

The solid electrolyte-containing liquid obtained by the above operation was put into a migration tank, and the positive electrode and the negative electrode were opposed to each other in the solid electrolyte-containing liquid at intervals of 5 mm. Of these, the ITO substrate on which the active material layer was laminated was used as the negative electrode. On the other hand, as the positive electrode, an ITO substrate having a conductive surface made of ITO (indium tin oxide) was used. Then, electrophoresis was performed by applying a direct current between the positive electrode and the negative electrode at a current density of 5.0 μA cm- ^{2 for 30 seconds.} Then, after pulling up the positive electrode (cathode) from the migration tank, it is naturally dried, and the active material layer and the solid electrolyte layer formed on the conductive surface of the ITO substrate are laminated in this order (electrode, positive electrode). ) Was obtained.

After that, the same operation is repeated, and electrophoresis is alternately performed in the active material-containing liquid and the solid electrolyte-containing liquid, and the three layers of the active material layer and the three layers of the solid electrolyte layer are alternately formed. I got a body. The obtained laminate (electrode) is shown in FIG.

FIG. 11 is a cross-sectional micrograph of the electrode formed in Example 2. In FIG. 11, the laminate formed in Example 2 is linearly divided in the lamination direction to expose the fracture surface, and the sample with the exposed fracture surface is subjected to a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, model number “ The results of observing the fracture surface at a magnification of 20 times by attaching it to the sample table of S-4800 ”) using carbon tape are shown.

In FIG. 11, the lower side of the paper surface is the ITO substrate. Further, the black granules were NMC powder, and it was confirmed that the NMC powder was layered (NMC layer). Further, the white substance was a solid electrolyte precursor (LPS precursor layer), and it was confirmed that this precursor was layered. LPS is a solid electrolyte produced by mixing _{raw material lithium sulfide (Li 2} S) and diphosphorus pentasulfide (P ₂ S ₅ ) at a ratio of 75 mol: 25 mol, and its structure. It contains Li ₃ PS ₄ . Further, the LPS precursor layer is a precursor of this LPS, and is converted into LPS through a treatment such as a heating step, for example. As described above, in Example 2, the active material layer deposited with a thickness of about 4 μm to 10 μm and the solid electrolyte layer deposited with a thickness of about 4 μm to 7 μm are alternately laminated on the ITO substrate (Substrate). It can be seen from FIG. 11 that the electrode structure was obtained.

[3] Example 3 (all-solid-state lithium-ion battery)
An aluminum substrate (diameter 10 mm), used in place of ITO substrate, the active material-containing solution 300MyuAcm ^-2 DC voltage in migration of the migration time 5 seconds, 10MyuAcm ^-2 DC voltage in migration of the solid electrolyte-containing solution, The LPS precursor layer (precursor layer of the solid electrolyte) was first formed on the aluminum substrate, and then the active material layer was formed in the same manner as in Example 2 described above, except that the migration time was set to 5 seconds. Then, a laminated body in which three solid electrolyte layers and two active material layers were alternately laminated was obtained. The uppermost layer of the laminate was a solid electrolyte layer. The obtained laminate was pre-dried at room temperature for 30 minutes and then vacuum-dried in a vacuum environment at 170 ° C. for 3 hours to change the precursor of the solid electrolyte into a solid electrolyte (LPS). As a result, a positive electrode was obtained.

A solid electrolyte having a thickness of 1000 μm obtained by pressure molding 80 mg of LPS was pressure-bonded to the surface of the solid electrolyte layer of the prepared positive electrode.

An indium foil having a thickness of 100 μm was pressure-bonded to the surface of the solid electrolyte of the obtained laminate (a laminate of a positive electrode and a solid electrolyte) to obtain an all-solid-state lithium-ion battery.

That is, the all-solid-state lithium-ion battery of Example 3 has a base material (current collector) made of an aluminum substrate, a solid electrolyte layer containing a solid electrolyte (solid electrolyte particles) laminated on the conductive surface thereof, and an active battery. It has a positive electrode with alternating layers of active material containing material (active material particles). Further, it has a solid electrolyte body laminated on the solid electrolyte layer of the uppermost layer (surface) of the positive electrode. Then, it has a negative electrode laminated on the surface of the solid electrolyte body. Then, in this all-solid-state lithium-ion battery, when a charging test was conducted with BTS-2004H manufactured by Nagano Co., Ltd., a charging capacity of about 2 mAhg ^-1 was shown in a charging time of 2 hours, and a result showing a slight charge was obtained. Was done.

Reference example 1 (all-solid-state lithium-ion battery)
<1> Preparation of active material-containing liquid (dispersion liquid) Using the following granular active material, an active material-containing liquid (dispersion liquid) was prepared by the following procedure.

(1) The following active material was put into a 10% by mass aqueous solution of polydiallyldimethylammonium chloride (cationic surfactant) and subjected to ultrasonic treatment to disperse it.

(2) Ion-exchanged water was added to the dispersion liquid of the above (1) for centrifugation, and the upper layer of the obtained separation liquid was removed to recover the lower layer.

(3) The operation of adding isopropyl alcohol to the liquid (recovered lower layer) of the above (2), performing a centrifugation treatment, removing the upper layer of the obtained separation liquid, and recovering the lower layer is repeated three times. The dispersion medium was replaced with isopropyl alcohol by removing water from the liquid. In this way, the active material is a dispersoid, isopropyl alcohol is used as a dispersion medium, and polyallyldimethylammonium chloride is used as a dispersant, and the active material-containing liquid in which the active material is dispersed (dispersion liquid, solid content concentration: 3% by mass). Got

Active material: Li-containing double oxide powder represented by _{Li (Ni x} Mn _y Co _z ) O _{2, average particle size 5 μm}

<2> Lamination of active material layer The active material-containing liquid obtained in <1> above was put into an electrophoresis tank, and positive and negative electrodes were opposed to each other at intervals of 10 mm in the active material-containing liquid. .. Of these, an aluminum substrate was used for the positive electrode and an aluminum substrate (diameter 10 mm) was used for the negative electrode. Then, a voltage having an asymmetric signal was applied between the positive electrode and the negative electrode for 45 seconds to perform electrophoresis.

Then, the negative electrode after the above-mentioned migration time was pulled up from the migration tank and then air-dried to obtain a laminate in which the active material layer formed on the conductive surface of the aluminum substrate was laminated.

Further, as the asymmetric signal, an asymmetric signal obtained by superimposing an AC voltage having a symmetric signal composed of a triangular wave (90V) and a DC voltage of 10V was used. This asymmetric signal is shown in FIG. However, V ₊ = 100V, V ₋ = 100V, T ₊ = 0.02 seconds, T ₋ = 0.02 seconds, frequency 20Hz).

<3> Preparation of solid electrolyte-containing liquid (dispersion liquid) In the same manner as the preparation of the solid electrolyte-containing liquid (dispersion liquid) of Example 1 <2> above, the dispersion liquid (suspension) in which the precursor of the solid electrolyte is dispersed is the same. , A solid electrolyte-containing liquid having a solid content concentration of 10 mg / mL) was obtained.

<4> Formation of Solid Electrolyte Layer The solid electrolyte-containing liquid obtained in <3> above was put into a migration tank, and positive and negative electrodes were opposed to each other in the solid electrolyte-containing liquid at intervals of 5 mm. .. An aluminum substrate was used as the positive electrode, and an aluminum substrate having an active material layer deposited on the conductive surface obtained in <2> above was used as the negative electrode. Then, a DC voltage was applied between the positive electrode and the negative electrode at a voltage of 25 V for 10 seconds to perform electrophoresis.

Then, the negative electrode after the above-mentioned migration time was pulled up from the migration tank, pre-dried at room temperature for 30 minutes, and then vacuum-dried in a vacuum environment of 170 ° C. for 3 hours to obtain an aluminum substrate (diameter 10 mm). ), The active material layer and the solid electrolyte layer were laminated in this order to obtain a laminate.

<5> of the stack 80mg of the solid electrolyte body _{of LPS (75Li 2 S · 25P 2 S} 5) were obtained by compression molding, a solid electrolyte body having a thickness of 1000 .mu.m, obtained by the <4> laminate It was pressure-bonded to the surface of the solid electrolyte layer of the body (electrode).

<6> Formation of Lithium Ion Battery A 100 μm-thick indium foil is pressure-bonded to the surface of the solid electrolyte of the laminate (laminate of electrode and solid electrolyte) obtained up to <5> above to form an all-solid-state battery. A type lithium ion battery was obtained.

That is, the all-solid-state lithium-ion battery 1 of Reference Example 1 has a base material (current collector) made of an aluminum substrate, and an active material layer containing an active material (active material particles) laminated on the conductive surface thereof. It has a positive electrode having a solid electrolyte layer containing a solid electrolyte (solid electrolyte particles) laminated on the surface of the active material layer. Further, a solid electrolyte layer is formed on the uppermost layer (surface) of the positive electrode, and a solid electrolyte is laminated on the solid electrolyte layer. Further, it has a negative electrode laminated on the surface of the solid electrolyte.

<7> Confirmation of charge / discharge The jig containing the all-solid-state lithium-ion battery obtained up to <6> above is enclosed in a glass container, the gas in the glass container is replaced with argon gas, and the measurement cell is used. Got Whether or not the obtained measuring cell could be charged or discharged was observed by a constant current, constant voltage, and charging method using an electrochemical measuring device (manufactured by Solartron, model "SI 1287"). Specifically, 3.8 V vs. Constant current charging was performed up to In-Li at a rate of 0.01 C, and then constant voltage charging was performed until 100 hours had passed. Immediately after that, 1.6 V vs. Discharge was performed at a rate of 0.01 C to the potential of In-Li. As a result, a discharge capacity of about 0.133 mAh / g could be obtained. That is, it was shown that an electrode (positive electrode) in which an active material and a solid electrolyte are laminated functions as a positive electrode by electrophoresis, and an all-solid-state lithium-ion battery equipped with this can be charged and discharged.

As the jig, the jig 70 shown in FIG. 12 was used. That is, the all-solid-state lithium ion battery 1 obtained in Reference Example 1 was housed in the through hole 74a of the tubular body 74 made of polyetheretherketone (PEEK). On the other hand, a pair (positive electrode side and negative electrode side) of holding pins 72 assembled by a stainless steel convex block and a stainless steel screw was prepared. Then, the holding pin 72 was inserted into the through hole 74a so as to sandwich the upper and lower sides of the all-solid-state lithium ion battery 1. Further, in order to tighten these holding pins 72, a pair of stainless pressing holding plates 71 (positive electrode side and negative electrode side) and three stainless steel tightening screws 73 for tightening the holding plates are prepared, and each holding pin 72 is tightened. The upper and lower sides were sandwiched between the holding plates 71, and these holding plates 71 were tightened with the tightening screws 73 (screw restraint pressure: 9 Nm), and the all-solid-state lithium-ion battery 1 was housed in the jig 70. Various energization is performed from the convex portion of the holding pin 72 (the portion marked with the reference numeral 72 on FIG. 12).

[4] Example 4
<1> Preparation of active material-containing liquid (dispersion liquid) As an anion exchange resin, an aqueous solution of a cationic polymer (Polyquaternium 11, Polyquaternium-11) of the following formula (2) is used, and NMC powder (average particle size 5 μm) is used as a granular active material. ) Was added and dispersed for 30 minutes using an ultrasonic cleaner. Then, the dispersion liquid was centrifuged, and the upper layer of the obtained separation liquid was removed to recover the lower layer. Ion-exchanged water was added to the recovered product, dispersed again with an ultrasonic cleaner, and then washed by repeating the process of collecting by centrifugation five times to remove excess ion-exchange resin.

Subsequently, the bis (2-ethylhexyl) sulfosuccinate bis (2-ethylhexyl) sodium sulfosuccinate (manufactured by Kishida Chemical Co., Ltd., trade name Aerosol OT), which is an anionic surfactant of the following formula (3), which serves as a counter ion supply source, is added to the above NMC-ion exchange resin dispersion. Ion exchange reaction replaced the ethyl sulfonate ion due to polyquaternium 11 with an anion due to sodium bis (2-ethylhexyl) sulfosuccinate. As a result, the counterion of the ion exchange group (quaternary ammonium group) becomes an anion derived from the sulfonic acid group having higher oil-based properties, and the ion exchange resin adhering to the active material is made into a salt mode. After that, the active material was recovered in the same manner as in Example 1 to obtain an active material-containing liquid having a solid concentration of 2% by mass using methylene chloride as the dispersion medium.

<2> Electrophoresis A method similar to that of Example 2 by using the active material-containing liquid obtained in <1> of this Example and the solid electrolyte-containing liquid obtained in the same manner as in <2> of Example 1. The solid electrolyte layer and the active material layer were sequentially formed on the substrate. Electrophoresis was performed multiple times for each of the active material and the solid electrolyte precursor. The migration time was 45 seconds and 15 seconds. The active material layer was formed at a direct current of 100 V and a current density of 30 μA cm- ² . The solid electrolyte layer was formed at a direct current of 100 V and a current density of 5 μA cm- ² .

FIG. 13 is a diagram showing a laminate (positive electrode) produced according to Example 4. Similar to FIG. 11, the lower side of the paper surface is the substrate. The black granules are NMC powders and the white substances are solid electrolyte precursors (LPS precursor layerers). FIG. 13 (a) shows a laminate in which each layer is formed by electrophoresis for 45 seconds, and FIG. 13 (b) shows a laminate in which each layer is formed by electrophoresis for 15 seconds. As can be seen from FIG. 13, by performing the electrophoresis for 45 seconds a plurality of times (active material layer 3 times, solid electrolyte layer 3 times), the active material layer and the solid electrolyte layer each have a layer thickness of about 8 μm and a plurality of layers. The formed laminate having a total thickness of 48 μm was obtained. Further, by setting the electrophoresis time to 15 seconds, the layer thickness can be reduced, and the active material layer and the solid electrolyte layer are each formed with a layer thickness of about 4 μm to 5 μm, and the total film thickness is 52 μm. It was shown that a laminate can be obtained.

Reference example 2 (all-solid-state lithium-ion battery)
Using the active material-containing liquid prepared in <1> of Example 4 and the solid electrolyte-containing liquid obtained in the same manner as in <2> of Example 1, on an aluminum substrate (diameter 10 mm) by electrophoresis. A laminate in which a 5 μm-thick active material layer and a 10 μm-thick solid electrolyte layer were laminated in this order was obtained. Next, a battery was formed using this laminated body in the same manner as in Reference Example 1, and the possibility of charging / discharging was observed by a constant current / constant voltage / charging method. Specifically, 3.8 V vs. Constant current charging was performed up to In-Li at a rate of 0.01 C, and then constant voltage charging was performed until 100 hours had passed. Immediately after that, 1.6 V vs. Discharge was performed at a rate of 0.01 C to the potential of In-Li. The result is shown in FIG. FIG. 14 is a diagram showing a charge / discharge curve of the battery produced in this reference example. The horizontal axis represents capacity and the vertical axis represents voltage. The solid line is the charge curve and the broken line is the discharge curve. As can be seen from this, a charge / discharge capacity of ^{several mAhg -1 was observed.}

Comparative Example 1
The solid electrolyte-containing liquid obtained in <2> of Example 1 was charged into the migration tank, and the positive electrode and the negative electrode were opposed to each other at intervals of 5 mm in the solid electrolyte-containing liquid. For the positive electrode and the negative electrode, a base material (ITO substrate) having a conductive surface made of ITO (indium tin oxide) was used. Then, a direct current was applied between the positive electrode and the negative electrode at a current density of 5.0 μA cm- ² for 45 seconds to perform electrophoresis of the solid electrolyte precursor. The negative electrodes that had passed the above migration time were each pulled up from the migration tank and then air-dried. As a result, a solid electrolyte layer formed on the conductive surface of the ITO substrate was obtained.

Ethylene carbonate (dielectric constant 90), propylene carbonate (dielectric constant 65), and acetonitrile (dielectric constant 37.5), which are polar solvents (aprotic), were prepared, and the above-mentioned solid electrolyte layer was immersed in the obtained solid electrolyte layer. Dissolved instantly.

The electrode of the present invention, its manufacturing method, and an all-solid-state lithium-ion battery can be used as a power source for home appliances such as personal computers and cameras, portable electronic devices such as mobile phones or communication devices, and electric tools such as power tools. , A large battery mounted on an electric vehicle (EV), a hybrid electric vehicle (HEV), etc., and an electrode constituting the large battery.

1: All-solid-state lithium-ion battery 2, 2a, 2b: Electrode 3: Solid electrolyte 21: Active material layer 22: Solid electrolyte layer 25: Base material 51: Base material 52, 521, 522: Particles 251: Conductive surface

Claims (14)

In the electrode used for an all-solid-state lithium-ion battery having a structure in which a solid electrolyte is arranged between a pair of electrodes.
An active material layer whose main component is an active material,
It is provided with a solid electrolyte layer containing a solid electrolyte as a main component.
The active material layer is a resin having an ion exchange group, and the first pair ion that ionizes all or part of the ion exchange group in a poor solvent of the solid electrolyte or its precursor and in an aprotonic solvent. An electrode characterized by containing an ion-bonded ion exchange resin. The ion exchange resin contained in the active material layer has an acidic group as the ion exchange group, and all or a part of the acidic group includes a cation of an organic onium salt as a first counterion. The electrode according to claim 1. The ion exchange resin is a polymer having a styrene-derived unit and an olefin-derived unit in the main chain, and the acidic group is a sulfonic acid group or a sulfonic acid-derived group. The electrode described. The electrode according to claim 2 or 3, wherein the organic onium salt is a quaternary phosphonium salt. At least one of a laminated structure in which the solid electrolyte layer is interposed between the layers of the two active material layers and a laminated structure in which the active material layer is interposed between the layers of the two solid electrolyte layers. The electrode according to any one of claims 1 to 4, wherein the electrode has a laminated structure of. The electrode according to any one of claims 1 to 5, wherein the solid electrolyte is a sulfide-based solid electrolyte. The electrode according to any one of claims 1 to 6, wherein the active material is a positive electrode active material. A method for manufacturing the electrodes used in an all-solid-state lithium-ion battery having a structure in which a solid electrolyte is arranged between a pair of electrodes.
The first deposition step of depositing the active material to form an active material layer by electrophoresis in an active material-containing liquid containing the active material, and
The solid electrolyte and / or its precursor is deposited by electrophoresis in a solid electrolyte-containing liquid containing the solid electrolyte and / or its precursor, and is adjacent to the active material layer formed in the first deposition step. A second deposition step for forming the solid electrolyte layer or its precursor layer is provided.
In the first deposition step, when the active material layer is formed after the solid electrolyte layer is formed, the active material-containing liquid which is a poor solvent of the solid electrolyte or its precursor and uses an aprotonic solvent as a dispersion medium. A method for producing an electrode, wherein the active material is electrophoresed in a state where an ion exchange resin having a first counter ion ionized in the dispersion medium is attached. 8. Claim 8 is characterized in that at least one of the first deposition step and the second deposition step is performed a plurality of times, and the active material layer and the solid electrolyte layer or a precursor layer thereof are alternately laminated. The method for manufacturing an electrode according to. A pretreatment step is provided in which an ion exchange resin is attached to the active material and all or part of the counterions of the ion exchange group are ion-exchanged with the first counterion.
The method for producing an electrode according to claim 8 or 9, wherein the first deposition step deposits an active material to which an ion exchange resin ion-exchanged in the pretreatment step is attached. The method for producing an electrode according to claim 10, wherein the pretreatment step is for exchanging a counterion of a sulfonic acid group or a group derived from sulfonic acid with a cation of an organic onium salt. 8. The ion exchange resin is a polymer having a styrene-derived unit and an olefin-derived unit in the main chain and having a sulfonic acid group or a sulfonic acid-derived group as an ion exchange group. The method for producing an electrode according to any one of 11 to 11. The method for producing an electrode according to any one of claims 8 to 12, wherein the dispersion medium used in the first deposition step is a solvent having a dielectric constant of 15 or less. An all-solid-state lithium-ion battery comprising the electrode according to any one of claims 1 to 7.

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