Electrode, electrode composite, secondary battery, and method for manufacturing electrode

Abstract

To provide an electrode that can alleviate expansion and contraction of active material particles, and can prevent a reduction in battery output when used in a secondary battery.SOLUTION: An electrode is applied to a secondary battery. The electrode includes active material particles, and resin having conductivity. The active material particles each have an inner surface. The resin having conductivity is located in contact with the inner surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electrode applied to a secondary battery, an electrode assembly, a secondary battery, and a method for manufacturing the electrode. [Background technology]

[0002] Generally, secondary batteries are composed of electrodes (positive and negative electrodes) and an electrolyte, and charge and discharge occur through the movement of ions between the electrodes via the electrolyte. Such secondary batteries are used in a wide range of applications, from small devices such as mobile phones to large devices such as electric vehicles. Therefore, there is a demand for further improvement in the performance of secondary batteries. In recent years, research and development has been progressing on so-called all-solid-state batteries, which use inorganic solid electrolytes as the electrolyte. By replacing the conventional organic electrolyte with a solid electrolyte, all-solid-state batteries are expected to improve the safety and increase the capacity and output of secondary batteries. On the other hand, in all-solid-state batteries, the contact between the electrolyte and the active material particles is easily broken due to the expansion and contraction of the active material particles during the process of ion insertion and desorption in the electrode. As a result, in all-solid-state batteries, the insertion and desorption of ions such as lithium ions into the active material particles is blocked, increasing the resistance of the electrode and significantly reducing the charge / discharge current, or so-called output characteristics. To address this issue, a technology has been known in which a lithium ion conductive polymer, which is more flexible than the electrolyte particles, is placed inside the electrode. Patent Document 1 discloses an electrode in which the outer surfaces of active material particles are partially coated with a lithium ion conductive polymer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-373643 [Patent Document 2] Japanese Patent Publication No. 2020-198301 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the present inventors have found that simply partially coating the outer surfaces of the active material particles with a polymer is not sufficient to improve the diffusibility of lithium ions within the electrode, for the following reasons. That is, active material particles in an electrode expand and contract during charging and discharging. Adjacent active material particles also expand and contract similarly. Therefore, even if the outer surfaces of active material particles are only partially coated with a polymer, the diffusion paths of lithium ions between the active material particles, consisting of the polymer and electrolyte particles, are likely to be blocked. Furthermore, in the active material particles of Patent Document 1, the surfaces of the active material particles are partially coated with both polymer and electrolyte particles. Therefore, contact between the polymer and the electrolyte particles is also limited, and the contact is likely to be blocked by the expansion and contraction of the active material particles. Therefore, the diffusion of lithium ions is likely to be restricted between the active material particles and the polymer. As a result, even solid electrolytes, which generally have higher ionic conductivity than polymers, tend to have a reduced effect on ion diffusion.

[0005] Furthermore, Patent Document 1 discloses methods for partially coating the surfaces of active material particles, such as mechanical milling and chemical coating treatment. However, these treatment methods have difficulty in achieving a uniform coating area and thickness for each particle, and there are problems with reproducibility as an electrode manufacturing method.

[0006] The present disclosure alleviates the expansion and contraction of active material particles, and suppresses a decrease in battery output when used in a secondary battery. The present disclosure provides an electrode that can suppress the deterioration of battery output. The present disclosure also provides an electrode composite including the electrode of the present disclosure. In addition, the present disclosure provides a secondary battery in which the deterioration of battery output is suppressed. Furthermore, the present disclosure provides a method for producing an electrode with high reproducibility. [Means for solving the problem]

[0007] An electrode according to one aspect of the present disclosure comprises: An electrode applied to a secondary battery, the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; The conductive resin is positioned so as to be in contact with the inner surface. death , The conductive resin contains a resin containing an ionic functional group and a supporting electrolyte. It is characterized by: An electrode according to one aspect of the present disclosure comprises: An electrode applied to a secondary battery, the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; the conductive resin is positioned so as to be in contact with the inner surface, The conductive resin is characterized by including a urethane resin containing an ionic functional group and a supporting electrolyte. An electrode according to one aspect of the present disclosure comprises: An electrode applied to a secondary battery, the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; the conductive resin is positioned so as to be in contact with the inner surface, A supporting electrolyte is contained between the active material particles, and the supporting electrolyte contains an inorganic electrolyte. An electrode according to one aspect of the present disclosure comprises: An electrode applied to a secondary battery, the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; the conductive resin is positioned so as to be in contact with the inner surface, the inner surface is continuous with the outer surface of the active material particle, The active material particles are characterized by having protrusions protruding from the outer surface.

[0008] An electrode composite according to one aspect of the present disclosure includes: An electrode composite including an electrode and an electrolyte layer that transfers an active material between the electrode and the electrolyte layer, the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; The conductive resin is positioned so as to be in contact with the inner surface. An electrode composite according to one aspect of the present disclosure includes: an electrode; and an electrolyte layer that transfers an active material between the electrode and the electrolyte layer; The electrode is characterized in that it is the electrode of the present disclosure.

[0009] A secondary battery according to one aspect of the present disclosure includes: a positive electrode and an electrolyte layer that transfers an active material between the positive electrode and the electrolyte layer; The positive electrode is the electrode according to any one of claims 1 to 22, The secondary battery is characterized in that it includes a negative electrode that transfers the active material between itself and the electrolyte layer.

[0010] A method for manufacturing an electrode according to one aspect of the present disclosure includes: A 1-1 step of preparing an electrode precursor including active material particles and having gaps between the active material particles; a 2-1 step of preparing a filling material to be filled into the electrode precursor; a 3-1 step of filling the filling material from the outside to the inside of the electrode precursor; and a 4-1 step of retaining the filler material filled inside the electrode precursor inside the electrode precursor. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide an electrode that can mitigate expansion and contraction of active material particles and suppress a decrease in battery output characteristics when used in a secondary battery. The present disclosure also provides an electrode composite including the electrode of the present disclosure. Furthermore, the present disclosure can provide a secondary battery in which a decrease in battery output is suppressed. In addition, the present disclosure can provide a method for manufacturing an electrode with high reproducibility. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is an image diagram showing a method for producing an electrode precursor. [Figure 2] FIG. 1 is a diagram schematically showing the configuration of a particle placement device 1. [Figure 3] FIG. 2 is a diagram schematically illustrating the configuration of a filling device. [Figure 4] Schematic diagram of a filler being carried on a first substrate. [Figure 5] FIG. 2 is an enlarged view of the vicinity of the surface of the first substrate. [Figure 6] FIG. 10 is a diagram schematically illustrating the configuration of a filling device when brush fibers are used as a support material. [Figure 7]FIG. 2 is a diagram schematically illustrating the configuration of a transfer unit. [Figure 8] 10 is an enlarged view of the vicinity of the surface of the second substrate during the filling process using the second filling device. [Figure 9] FIG. 3 is a diagram schematically showing the second substrate after the first particles P1 and the second particles P2 have been transferred. [Figure 10] FIG. 2 is a diagram schematically showing the configuration of a particle placement device 2. [Figure 11] FIG. 2 is a diagram schematically illustrating the configuration of a laminate forming apparatus. [Figure 12] FIG. 2 is a diagram schematically illustrating the configuration of a sintering treatment apparatus. [Figure 13] SEM images of laminates and three-dimensional objects at each stage of the electrode manufacturing process. [Figure 14] 1 is a BIB-SEM image of a three-dimensional object according to one embodiment of the present disclosure. [Figure 15] FIG. 1 is an explanatory diagram of a mechanism relating to a three-dimensional object according to one embodiment of the present disclosure. [Figure 16] FIG. 2 is a diagram showing the results of thermogravimetry of a resin substrate. [Figure 17] Figure showing the results of thermogravimetry and mass spectrometry measurements. [Figure 18-1] FIG. 10 shows LCO particles after the third step. [Figure 18-2] FIG. 10 shows the results of STEM-EDX on LCO particles after the third step. [Figure 19] 1 is an image diagram showing a method for manufacturing an electrode. [Figure 20] FIG. 3 is a schematic diagram showing one embodiment of step 3-1. [Figure 21] FIG. 1 is a diagram showing a charge / discharge curve of a secondary battery. [Figure 22] FIG. 2 is a diagram showing an electron microscope image of a cross section of a positive electrode. [Figure 23] FIG. 2 is a low-magnification electron microscope image of a cross section of a positive electrode. [Figure 24] 1 is a schematic diagram illustrating features of the present disclosure. [Figure 25] FIG. 2 is a diagram showing an electron microscope image of a cross section of a positive electrode. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the present disclosure, expressions such as "XX or more and YY or less" or "XX to YY" representing a numerical range mean a numerical range including the upper and lower limits, which are the endpoints, unless otherwise specified. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily. Furthermore, in the present disclosure, expressions such as "at least one selected from the group consisting of XX, YY, and ZZ" mean any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ.

[0014] As a result of investigations by the present inventors, it was found that it is important to place a conductive resin (polymer) at an appropriate position relative to the active material particles in the electrode. This makes it easier to mitigate the expansion and contraction of each active material particle inside the electrode while suppressing a decrease in ion diffusion within the electrode. In the present disclosure, the electrode of the present disclosure is realized by filling an electrode precursor with a polymer using the method described below and retaining it inside the electrode precursor. In the present disclosure, the mitigation of expansion and contraction of each active material particle is conveniently evaluated using an index known as the "cycle characteristics" of a prototype battery, and the ionic conductivity is conveniently evaluated using an index known as the "rate characteristics" of a prototype battery.

[0015] The electrode of the present disclosure is an electrode for use in a secondary battery. The electrode includes active material particles and a conductive resin. By including the active material particles and the conductive resin in the electrode, ions can be transferred between the electrodes via an electrolyte, allowing the electrode to be used as an electrode.

[0016] The active material particles preferably have an inner surface, and the conductive resin is preferably positioned so as to be in contact with the inner surface of the active material particles, where the inner surface refers to the surface present on the inside of the active material particles. In this way, by having the conductive resin in contact with the inner surface of the active material particles, the flexibility of the conductive resin can mitigate expansion and contraction of the active material particles while making it easier to suppress a decrease in ion diffusion within the electrode, thereby suppressing a decrease in output characteristics. For example, by performing a sintering treatment as in the third step described below, the active material particles can be made to have an inner surface within the particles. Furthermore, by filling the electrode precursor with a filler material as in the third step described below, the conductive resin can be positioned so as to be in contact with the inner surface of the active material particles. The fact that the active material particles have an inner surface within the particles can be confirmed by the measurement method described below. Furthermore, the fact that the conductive resin is positioned so as to be in contact with the inner surface of the active material particles can be confirmed by the measurement method described below.

[0017] The inner surfaces of the active material particles preferably have internal pores (hereinafter also referred to as "communicating pores") that communicate with the outer surfaces of the active material particles. By forming such internal pores, it becomes easier to position the filler material so that it contacts the inner surfaces of the active material particles during the step 3-1 described below. An example of a method for forming such inner pores is a sintering treatment such as that described in the third step below. Whether or not the inner surfaces of the active material particles have such inner pores can be confirmed by the measurement method described below.

[0018] Furthermore, the inner surfaces of the active material particles are preferably continuous with the outer surfaces of the active material particles, which makes it easier to position the conductive resin so that it contacts the inner surfaces of the active material particles in the step 3-1 described below. Moreover, examples of active material particles having such an inner surface include active material particles having a core portion and a shell portion. As a method for forming such an inner surface, for example, a sintering treatment such as that in the third step described below can be mentioned.

[0019] The active material particles preferably have outer surfaces, and the conductive resin is preferably disposed in contact with the outer surfaces of the active material particles so as to connect the active material particles together. Here, the outer surfaces refer to the surfaces that exist on the outside of the active material particles. In this way, the conductive resin is arranged in contact with the outer surfaces of the active material particles and connects the active material particles, and the flexibility of the conductive resin helps to mitigate the expansion and contraction of the active material particles while also making it easier to suppress a decrease in ion diffusion within the electrode, thereby suppressing a decrease in output characteristics. For example, by filling the electrode precursor with a filler material as in step 3-1 described below, the conductive resin can be arranged so as to contact the outer surfaces of the active material particles and connect the active material particles. Whether the conductive resin is in contact with the outer surfaces of the active material particles and arranged so as to connect the active material particles can be confirmed by the measurement method described below.

[0020] The active material particles preferably have protrusions. The shape of the protrusions is not particularly limited, and examples thereof include whiskers, which are beard-like, and dendrites, which are dendritic. Examples of the protrusions include those protruding from the outer surface. Having such protrusions increases the surface area of ​​the active material particles. As a result, when the electrode contains an electrolyte, the contact area with the electrolyte can be increased. The protrusions can be formed, for example, by performing a sintering process, as in the third step described below. The presence of protrusions in the active material particles can be confirmed by observing the cross section of the electrode, which will be described later.

[0021] The active material particles are not particularly limited and known active material particles can be used. For example, lithium-containing composite oxides can be used. Specific examples include Li-Co oxide active material particles such as LiCoO2 (lithium cobalt oxide), LiMO2 (where M is an element selected from the group consisting of Ni, Mn, and Co), Li-PO4 oxide active material particles, lithium vanadium compounds (Li3V2(PO4)3, LiVOPO4), and olivine-type phosphate compounds (LiMPO4 (where M is one or more elements selected from the group consisting of Co, Ni, Mn, Fe, Mg, V, Nb, Ti, Al, and Zr)). Active material particles that do not contain lithium can also be used. Specific examples include metal oxides (MnO2, V2O5, etc.) and fluorides (FeF3, VF3, etc.). When using active material particles that do not contain lithium, metallic lithium containing lithium or a negative electrode active material doped with lithium ions is placed as the negative electrode active material, and the battery can be used by starting with discharge. In addition, the negative electrode active material particles, such as graphite, Si, and lithium titanate (LTO), are used. It is also possible.

[0022] The present inventors have revealed that, among the above positive electrode active material particles, the use of Li-Co oxide-based active material particles increases the surface area of ​​the positive electrode active material particles, thereby improving the output characteristics of the secondary battery (Patent Document 2). Furthermore, Li-PO4 oxide-based active material particles are very stable due to the strong covalent bonds between PO and the suppression of oxygen release. Therefore, among the above positive electrode active material particles, it is preferable to include Li-Co oxide-based active material particles and Li-PO4 oxide-based active material particles.

[0023] The active material particles may be commercially available products or may be separately prepared as materials. As the Li-Co oxide active material particles, for example, Cellseed C-5H (trade name, manufactured by Nippon Chemical Industry Co., Ltd.) (LiCoO2) can be used. As the LiMO2 (M is an element selected from the group consisting of Ni, Mn, and Co), Cellseed NMC (trade name, manufactured by Nippon Chemical Industry Co., Ltd.) (LiNi (1-x-y) Mn x Co y O2) can be used. As the Li-PO4 oxide-based active material particles, Li3V2(PO4)3 (manufactured by Tokyo Chemical Industry Co., Ltd.) or LiFePO4 (manufactured by Toshima Manufacturing Co., Ltd.) can be used. When active material particles with low electronic conductivity such as Li3V2(PO4)3 or LiFePO4 are used, the particle surfaces may be coated with carbon by a general method before use. The active material particles may be used alone or in combination of two or more kinds.

[0024] The electrode preferably contains at least one selected from the group consisting of a conductive resin, a conductive additive, and a supporting electrolyte between the active material particles, and more preferably contains a conductive resin and a supporting electrolyte between the active material particles. This improves the diffusibility of lithium ions within the electrode and reduces electrode resistance. Furthermore, by reducing the number of isolated active material particles that cannot exchange lithium ions within the electrode, the actual capacity of the battery can be improved. The fact that the electrode contains at least one selected from the group consisting of a conductive resin, a conductive additive, and a supporting electrolyte between the active material particles can be confirmed by the results of element mapping in the cross-sectional observation described below.

[0025] The conductive resin is not particularly limited, and any known resin can be used as long as it has conductivity. For example, the conductive resin may be a resin with ionic conductivity. Examples of the conductive resin include gel electrolytes and dry polymer electrolytes. From the viewpoint of safety, dry polymer electrolytes that do not contain flammable electrolytic solutions are preferred. The conductive resin preferably contains at least one of polyurethane, polyacrylic, and polyether in its main chain structure. Polyether, urethane resin containing polyether, and acrylic resin containing polyether are more preferred, and urethane resin containing polyether is even more preferred. The polyether is preferably a copolymer of polyethylene glycol and polypropylene glycol. The conductive resin preferably contains an ionic functional group such as a cationic structure in its structure to have conductivity. The conductive resin preferably contains an anion. Furthermore, the conductive resin may have conductivity by containing a conductive assistant or a supporting electrolyte.

[0026] The ionic group is preferably at least one cationic structure selected from the group consisting of cationic nitrogen-containing heterocyclic structures and ammonium cations having a linear or branched structure. The cationic nitrogen-containing heterocyclic structure is not particularly limited, but may be a four-membered ring to an eight-membered ring. Examples of the cationic nitrogen-containing heterocyclic structure include cationic nitrogen-containing aromatic heterocyclic structures such as imidazolium cation, pyridinium cation, pyrazinium cation, pyrimidinium cation, azepinium cation, quinolinium cation, isoquinolinium cation, indolinium cation, quinoxalinium cation, triazolium cation, triazinium cation, and thiazolinium cation; and cationic nitrogen-containing aliphatic heterocyclic structures such as pyrrolidinium cation, pyrrolinium cation, imidazolinium cation, imidazolidinium cation, piperazinium cation, azepanium cation, diazepanium cation such as 1,3-diazepanium cation and 1,4-diazepanium cation, azocanium cation, oxazolinium cation, and morpholinium cation. Among these, the cationic nitrogen-containing aromatic heterocyclic structure is preferably at least one selected from the group consisting of imidazolium cation, pyridinium cation, and pyrazinium cation, and more preferably an imidazolium cation. The cationic nitrogen-containing aliphatic heterocyclic structure is preferably at least one selected from the group consisting of a pyrrolidinium cation and a piperazinium cation, and more preferably a pyrrolidinium cation.

[0027] Examples of the ammonium cation having a straight chain or branched structure include primary ammonium cations, secondary ammonium cations, tertiary ammonium cations and quaternary ammonium cations, and among these, quaternary ammonium cations are preferred. The hydrocarbon group of the ammonium cation is not particularly limited, and may be, for example, a hydrocarbon group having 1 to 8 carbon atoms (preferably 1 to 4, more preferably 1 to 2, and even more preferably 1). The ammonium cation having a linear or branched structure may have a structure represented by the following formula (4). The cationic structure may have any substituent such as a hydrocarbon group. For example, the cationic structure preferably includes at least one structure selected from the group consisting of structures represented by the following formulas (1) to (6). Each structure represented by formulas (1) to (6) will be described below.

[0028] The structure represented by formula (1) will be explained below. [ka] In formula (1), R 1 and R 2 represents a hydrocarbon group that forms a five-membered nitrogen-containing aromatic heterocyclic structure together with the nitrogen atom to which it is bonded, and Z 1 ~Z 3 each independently represents a structure represented by the following formula (X), a hydrogen atom, a hydroxyl group, a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1), or a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1) and a hydroxyl group, and Z 1 ~Z 3 At least one of the above is a structure represented by the following formula (X), 1 represents an integer of 0 to 3 (preferably 0 or 1).

[0029] The hydrocarbon group having 1 to 4 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom. The hydrocarbon group having 1 to 4 carbon atoms and a hydroxyl group is preferably a hydroxyalkyl group having 1 to 4 carbon atoms, more preferably a hydroxyalkyl group having 1 or 2 carbon atoms, and even more preferably a hydroxyalkyl group having 1 carbon atom. The hydrocarbon group may have two or more hydroxyl groups. The structure represented by formula (1) is composed of at least one structure represented by the following formula (X) and two and a nitrogen atom. The nitrogen-containing aromatic heterocyclic structure in formula (1) is preferably an imidazolium cation. The method for incorporating the structure represented by formula (1) into the structure of a conductive resin is not particularly limited. For example, when the conductive resin is a urethane resin, at least one structure represented by formula (1) is incorporated into the structure of the urethane resin by reacting an ionic compound having a structure corresponding to the cation of the five-membered nitrogen-containing aromatic heterocyclic structure represented by formula (1) with an isocyanate compound.

[0030] As the five-membered nitrogen-containing aromatic heterocyclic structure in formula (1), the cationic nitrogen-containing aromatic heterocyclic structures described in the above section on cation structures can be used, and among these, imidazolium cations are preferred. Examples of ionic compounds having a structure corresponding to the cation of the five-membered nitrogen-containing aromatic heterocyclic structure in formula (1) include Z 1 ~Z 3 and n is a hydroxyl group, and at least one of the hydroxyl groups is a linear or branched divalent hydrocarbon. As an example of this ionic compound, an ionic compound containing an imidazolium cation is given below.

[0031] 1-methyl-3-hydroxymethylimidazolium cation, 1-methyl-3-(2-hydroxyethyl)imidazolium cation, 1-methyl-3-(3-hydroxypropyl)imidazolium cation, 1-methyl-3-(4-hydroxybutyl)imidazolium cation, 1-ethyl-3-(2-hydroxyethyl)imidazolium cation, 1-n-butyl-3-(2-hydroxyethyl)imidazolium cation, 1,3-dimethyl-2-(2-hydroxyethyl)imidazolium cation, 1,3-dimethyl-2-(4-hydroxybutyl)imidazolium cation, 1,3-dimethyl-4-(2-hydroxyethyl)imidazolium cation; 1,3-bishydroxymethylimidazolium cation, 1,3-bis(2-hydroxyethyl)imidazolium cation, 2-methyl-1,3-bishydroxymethylimidazolium cation, 2-methyl-1,3-bis(2-hydroxyethyl)imidazolium cation, 4-methyl-1,3-bis(2-hydroxyethyl)imidazolium cation, 2-ethyl-1,3-bis(2-hydroxyethyl)imidazolium cation, 4-ethyl-1,3-bis(2-hydroxyethyl)imidazolium cation, 2-n-butyl 1,3-bis(2-hydroxyethyl)imidazolium cation, 4-n-butyl-1,3-bis(2-hydroxyethyl)imidazolium cation, 1,3-bis(3-hydroxypropyl)imidazolium cation, 1,3-bis(4-hydroxybutyl)imidazolium cation, 1-methyl-2,3-bis(2-hydroxyethyl)imidazolium cation, 1-methyl-3,4-bis(2-hydroxyethyl)imidazolium cation, 1-methyl-3,5-bis(2-hydroxyethyl)imidazolium cation; 1,2,3-trishydroxymethylimidazolium cation, 1,2,3-tris(2-hydroxyethyl)imidazolium cation, 1,2,3-tris(3-hydroxypropyl)imidazolium cation, 1,2,3-tris(4-hydroxybutyl)imidazolium cation, 1,3,4-trishydroxymethylimidazolium cation, 1,3,4-tris(2-hydroxyethyl)imidazolium cation, 1,3,4-tris(3-hydroxypropyl)imidazolium cation, 1,3,4-tris(4-hydroxybutyl)imidazolium cation; and their derivatives.

[0032] The structure represented by formula (2) will be explained below. [ka] In formula (2), R 3 represents a hydrocarbon group that forms a nitrogen-containing aromatic heterocyclic structure together with the nitrogen atom to which it is bonded, and Z 4 and Z 5each independently represents a structure represented by formula (X), a hydrogen atom, a hydroxyl group, a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1), or a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1) and a hydroxyl group, and Z 4 and Z 5 At least one of the groups is a structure represented by formula (X), and d 2 represents an integer of 0 to 5 (preferably 0 or 1).

[0033] The hydrocarbon group having 1 to 4 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom. The hydrocarbon group having 1 to 4 carbon atoms and a hydroxyl group is preferably a hydroxyalkyl group having 1 to 4 carbon atoms, more preferably a hydroxyalkyl group having 1 or 2 carbon atoms, and even more preferably a hydroxyalkyl group having 1 carbon atom. The hydrocarbon group may have two or more hydroxyl groups. The structure represented by formula (2) represents a cation of a nitrogen-containing aromatic heterocyclic structure having at least one structure represented by the following formula (X). The nitrogen-containing aromatic heterocyclic structure in formula (2) may be a five- to eight-membered ring, and is preferably a five- or six-membered ring. The nitrogen-containing aromatic heterocyclic structure in formula (2) is preferably, for example, a pyridinium cation. There are no particular limitations on the method for incorporating the structure represented by formula (2) into the structure of a conductive resin. For example, when the conductive resin is a urethane resin, at least one structure represented by formula (2) is incorporated into the structure of the urethane resin by reacting an ionic compound having a structure corresponding to the cation of the nitrogen-containing aromatic heterocyclic structure represented by formula (2) with an isocyanate group.

[0034] As the nitrogen-containing aromatic heterocyclic structure in formula (2), the cationic nitrogen-containing aromatic heterocyclic structures described in the above section on cation structures can be used, and among these, pyridinium cations are preferred. Examples of ionic compounds having a structure corresponding to the cation of the nitrogen-containing aromatic heterocyclic structure in formula (2) include Z 4 and Z 5and n is a hydroxyl group, and n is a divalent hydrocarbon having a straight chain or a branched chain. As an example of this ionic compound, an ionic compound containing a pyridinium cation is given below.

[0035] 1-Hydroxymethylpyridinium cation, 1-(2-hydroxyethyl)pyridinium cation, 1-(3-hydroxypropyl)pyridinium cation, 1-(4-hydroxybutyl)pyridinium cation, 2-methyl-1-(2-hydroxyethyl)pyridinium cation, 3-methyl-1-(2-hydroxyethyl)pyridinium cation, 4-methyl-1-(2-hydroxyethyl)pyridinium cation, 3-ethyl-1-(2-hydroxyethyl)pyridinium cation, 3-n-butyl-1-(2-hydroxyethyl)pyridinium cation, 1-methyl-2-hydroxymethylpyridinium cation, 1-methyl-3-hydroxymethylpyridinium cation, 1-methyl-4-hydroxymethylpyridinium cation, 1-methyl-2-(2-hydroxyethyl)pyridinium cation, 1-methyl-3-(2-hydroxyethyl)pyridinium cation, 1-methyl-4-(2-hydroxyethyl)pyridinium cation, 1-ethyl-3-(2- hydroxyethyl)pyridinium cation, 1-n-butyl-3-(2-hydroxyethyl)pyridinium cation, 2-methyl-4-n-butyl-1-(2-hydroxyethyl)pyridinium cation; 1,2-bishydroxymethylpyridinium cation, 1,3-bishydroxymethylpyridinium cation, 1,4-bishydroxymethylpyridinium cation, 1,2-bis(2-hydroxyethyl)pyridinium cation, 1,3-bis(2-hydroxyethyl)pyridinium cation, 1,4-bis(2-hydroxyethyl)pyridinium cation, 1,2-bis(3-hydroxypropyl)pyridinium cation, 1,2-bis(3-hydroxypropyl)pyridinium cation, 1,3-bis(3-hydroxypropyl)pyridinium cation, 1, 4-bis(3-hydroxypropyl)pyridinium cation, 1,2-bis(4-hydroxybutyl)pyridinium cation, 1,3-bis(4-hydroxybutyl)pyridinium cation, 1,4-bis(4-hydroxybutyl)pyridinium cation, 2-methyl-1,3-bis(2-hydroxyethyl)pyridinium cation, 2-ethyl-1,3-bis(2-hydroxyethyl)pyridinium cation, 5-methyl-1,3-bis(2-hydroxyethyl)pyridinium cation, 5-ethyl-1,3-bis(2-hydroxyethyl)pyridinium cation; 1,2,4-trishydroxymethylpyridinium cation, 1,2,4-tris(2-hydroxyethyl)pyridinium cation, 1,2,4-tris(3-hydroxypropyl)pyridinium cation, 1,2,4-tris(4-hydroxybutyl)pyridinium cation, 1,3,5-trishydroxymethylpyridinium cation, 1,3,5-tris(2-hydroxyethyl)pyridinium cation, 1,3,5-tris(3-hydroxypropyl)pyridinium cation, 1,3,5-tris(4-hydroxybutyl)pyridinium cation; and their derivatives.

[0036] The structure represented by formula (3) will be explained below. [ka] In formula (3), R 4 and R 5represents a hydrocarbon group that forms a six-membered nitrogen-containing aromatic heterocyclic structure together with the nitrogen atom to which it is bonded, and Z 6 and Z 7 each independently represents a structure represented by the following formula (X), a hydrogen atom, a hydroxyl group, a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1), or a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1) and a hydroxyl group, and Z 6 and Z 7 At least one of the above is a structure represented by the following formula (X), 3 represents an integer of 0 to 4 (preferably 0 to 2).

[0037] The hydrocarbon group having 1 to 4 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom. The hydrocarbon group having 1 to 4 carbon atoms and a hydroxyl group is preferably a hydroxyalkyl group having 1 to 4 carbon atoms, more preferably a hydroxyalkyl group having 1 or 2 carbon atoms, and even more preferably a hydroxyalkyl group having 1 carbon atom. The hydrocarbon group may have two or more hydroxyl groups. The structure represented by formula (3) represents a cation of a six-membered nitrogen-containing aromatic heterocyclic structure having at least one structure represented by the following formula (X) and two nitrogen atoms. The nitrogen-containing aromatic heterocyclic structure in formula (3) is preferably, for example, a pyrazinium cation. There are no particular limitations on the method for incorporating the structure represented by formula (3) into the structure of a conductive resin. For example, when the conductive resin is a urethane resin, at least one structure represented by formula (3) is incorporated into the structure of the urethane resin by reacting an ionic compound having a structure corresponding to the cation of the six-membered nitrogen-containing aromatic heterocyclic structure represented by formula (3) with an isocyanate compound.

[0038] As the six-membered nitrogen-containing aromatic heterocyclic structure in formula (3), the cationic nitrogen-containing aromatic heterocyclic structures described in the above section on cation structures can be used, and among these, pyrimidinium cations and pyrazinium cations are preferred. Examples of ionic compounds having a structure corresponding to the cation of the six-membered nitrogen-containing aromatic heterocyclic structure in formula (3) include Z 6 and Z 7 and n is a hydroxyl group, and is a linear or branched divalent hydrocarbon. Examples of such ionic compounds include ionic compounds containing pyrimidium cations, such as:

[0039] 1,4-bis(2-hydroxyethyl)pyrimidinium cation, 1,5-bis(3-hydroxybutyl)pyrimidinium cation, 1-(4-hydroxybutyl)-4-(2-hydroxyethyl)pyrimidinium cation, 1,4-bis(2-hydroxyethyl)-2-methylpyrimidinium cation; and derivatives thereof.

[0040] The structure represented by formula (4) will be explained below. [ka] In formula (4), R 7 represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2 carbon atoms), Z 8 ~Z 10 each independently represents a structure represented by the following formula (X), a hydrogen atom, a hydroxyl group, a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1), or a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1) and a hydroxyl group, and Z 8 ~Z 10 At least one of the above has a structure represented by the following formula (X).

[0041] The hydrocarbon group having 1 to 4 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom. The hydrocarbon group having 1 to 4 carbon atoms and a hydroxyl group is preferably a hydroxyalkyl group having 1 to 4 carbon atoms, more preferably a hydroxyalkyl group having 1 or 2 carbon atoms, and even more preferably a hydroxyalkyl group having 1 carbon atom. The hydrocarbon group may have two or more hydroxyl groups. The structure represented by formula (4) represents an ammonium cation having at least one structure represented by the following formula (X). There are no particular limitations on the method for incorporating the structure represented by formula (4) into the structure of a conductive resin. For example, when the conductive resin is a urethane resin, at least one structure represented by formula (4) is incorporated into the structure of the urethane resin by reacting an ionic compound having a structure corresponding to the ammonium cation represented by formula (4) with an isocyanate compound.

[0042] As the ammonium cation in formula (4), ammonium cations having a linear or branched structure as described in the above-mentioned cation structure column can be used, among which quaternary ammonium cations Ammonium cations are preferred. Examples of ionic compounds having a structure corresponding to the ammonium cation in formula (4) include Z 8 ~Z 10 and n is a hydroxyl group, and n is a divalent hydrocarbon having a straight chain or a branched chain. Examples of such ionic compounds include ionic compounds containing a quaternary ammonium cation.

[0043] 2-hydroxyethyltrimethylammonium cation, 2-hydroxyethyltriethylammonium cation, 4-hydroxybutyltrimethylammonium cation, 4-hydroxybutyl-tri-n-butylammonium cation; Bis(hydroxymethyl)dimethylammonium cation, bis(2-hydroxyethyl)dimethylammonium cation, bis(3-hydroxypropyl)dimethylammonium cation, bis(4-hydroxybutyl)dimethylammonium cation; Tris(hydroxymethyl)methylammonium cation, tris(2-hydroxyethyl)methylammonium cation, tris(3-hydroxypropyl)methylammonium cation, tris(4-hydroxybutyl)methylammonium cation; and their derivatives.

[0044] The structure represented by formula (5) will be explained below. [ka] In formula (5), R 8 and R 9 represents a hydrocarbon group that forms a nitrogen-containing aliphatic heterocyclic structure together with the nitrogen atom to which it is bonded, and Z 11 ~Z 14 each independently represents a structure represented by the following formula (X), a hydrogen atom, a hydroxyl group, a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1), or a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1) and a hydroxyl group, and Z 11 ~Z 14 At least one of the above is a structure represented by the following formula (X), 4 represents an integer of 0 to 4 (preferably 0 to 2).

[0045] The hydrocarbon group having 1 to 4 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom. The hydrocarbon group having 1 to 4 carbon atoms and a hydroxyl group is preferably a hydroxyalkyl group having 1 to 4 carbon atoms, more preferably a hydroxyalkyl group having 1 or 2 carbon atoms, and even more preferably a hydroxyalkyl group having 1 carbon atom. The hydrocarbon group may have two or more hydroxyl groups. The structure represented by formula (5) represents a cation of a nitrogen-containing aliphatic heterocyclic structure having at least one structure represented by the following formula (X) and two nitrogen atoms. The nitrogen-containing aliphatic heterocyclic structure in formula (5) may be a five- to eight-membered ring, and is preferably a five- or six-membered ring. The nitrogen-containing aliphatic heterocyclic structure in formula (5) is preferably, for example, a piperazinium cation. There are no particular limitations on the method for incorporating the structure represented by formula (5) into the structure of a conductive resin. For example, when the conductive resin is a urethane resin, at least one structure represented by formula (5) is incorporated into the structure of the urethane resin by reacting an ionic compound having a structure corresponding to the cation of the nitrogen-containing aliphatic heterocyclic structure represented by formula (5) with an isocyanate compound.

[0046] As the nitrogen-containing aliphatic heterocyclic structure in formula (5), the cationic nitrogen-containing aliphatic heterocyclic structures described in the above column for cation structure can be used, and among these, piperazinium cations are preferred. Examples of ionic compounds having a structure corresponding to the cation of the nitrogen-containing aliphatic heterocyclic structure in formula (5) include Z 11 ~Z 14 and n is a hydroxyl group, and is a linear or branched divalent hydrocarbon. Examples of such ionic compounds include ionic compounds containing a piperazinium cation, as follows:

[0047] 1,1-bis(2-hydroxyethyl)piperazinium cation, 1,1,4-tris(2-hydroxyethyl)piperazinium cation, 1,4-bis(3-hydroxypropyl)-1-ethylpiperazinium cation, 1,4-bis(2-hydroxyethyl)-1,3-diethylpiperazinium cation; and derivatives thereof.

[0048] The structure represented by formula (6) will be explained below. [ka] In formula (6), R 9 represents a hydrocarbon group that forms a nitrogen-containing aliphatic heterocyclic structure together with the nitrogen atom to which it is bonded, and Z 15 ~Z 17 each independently represents a structure represented by formula (X), a hydrogen atom, a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1), or a hydrocarbon group having 1 to 4 carbon atoms (preferably 1 to 2, more preferably 1) and a hydroxyl group, and Z15 ~Z 17 At least one of the above is a structure represented by the following formula (X), 5 represents an integer of 0 to 4 (preferably 0 or 1).

[0049] The hydrocarbon group having 1 to 4 carbon atoms is preferably an alkyl group having 1 to 4 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom. The hydrocarbon group having 1 to 4 carbon atoms and a hydroxyl group is preferably a hydroxyalkyl group having 1 to 4 carbon atoms, more preferably a hydroxyalkyl group having 1 or 2 carbon atoms, and even more preferably a hydroxyalkyl group having 1 carbon atom. The hydrocarbon group may have two or more hydroxyl groups. The structure represented by formula (6) represents a cation of a nitrogen-containing aliphatic heterocyclic structure having at least one structure represented by the following formula (X). The nitrogen-containing aliphatic heterocyclic structure in formula (6) may be a five- to eight-membered ring, and is preferably a five- or six-membered ring. The nitrogen-containing aliphatic heterocyclic structure in formula (6) is preferably, for example, a pyrrolidinium cation. There are no particular limitations on the method for incorporating the structure represented by formula (6) into the structure of a conductive resin. For example, when the conductive resin is a urethane resin, at least one structure represented by formula (6) is incorporated into the structure of the urethane resin by reacting an ionic compound having a structure corresponding to the cation of the nitrogen-containing aliphatic heterocyclic structure represented by formula (6) with an isocyanate group.

[0050] As the nitrogen-containing aliphatic heterocyclic structure in formula (6), the cationic nitrogen-containing aliphatic heterocyclic structures described in the above section on cation structures can be used, and among these, a pyrrolidinium cation is preferred. Examples of ionic compounds having a structure corresponding to the cation of the nitrogen-containing aliphatic heterocyclic structure in formula (6) include Z 15 ~Z 17 and at least one of the groups is a divalent hydrocarbon having a hydroxyl group and a straight or branched chain. Examples of ionic compounds containing pyrrolidinium cations include the following:

[0051] 1-methyl-1,2-bis(2-hydroxyethyl)pyrrolidinium cation, 1-ethyl-1,2-bis(2-hydroxyethyl)pyrrolidinium cation, 1-butyl-1,2-bis(2-hydroxyethyl)pyrrolidinium cation, 1-methyl-1,2-bis(4-hydroxybutyl)pyrrolidinium cation; and derivatives thereof.

[0052] The structure represented by formula (X) will be explained below. [ka] In formula (X), R 10 represents a linear or branched divalent hydrocarbon group, the symbol "*" represents a bond to a nitrogen atom in formulas (1) to (6) or a bond to a carbon atom in a nitrogen-containing heterocyclic structure in formulas (1) to (3) and formulas (5) to (6), and the symbol "**" represents a bond to a carbon atom in a polymer chain constituting a urethane resin having a cationic structure. R 10 is preferably a linear or branched alkylene group having 1 to 8 carbon atoms (preferably 1 to 4, more preferably 1 to 2). 10 may have an optional substituent such as a hydroxyl group.

[0053] For example, when the conductive resin is a urethane resin, the structure represented by formula (X) may be a structure formed by reacting an ionic compound having a structure corresponding to the cation of the structure represented by formulas (1) to (6) with an isocyanate compound. The isocyanate compound is preferably a urethane prepolymer obtained by reacting a polyol such as polyether polyol with an isocyanate compound. For example, polymeric MDI can be used as the isocyanate compound.

[0054] Among the structures represented by formulas (1) to (6), when the cationic structure includes the structure represented by formula (1) or the structure represented by formula (2), the stability as a cation is high and the dissociation rate with the anion, which is the counter ion, is high. Therefore, when a lithium salt is contained as a supporting electrolyte, the cationic structure is likely to interact with the anion of the lithium salt, promoting the dissociation of the lithium salt and improving the ionic conductivity, which is preferable.

[0055] When the conductive resin is a urethane resin, the urethane resin preferably has a first urethane bond and a second urethane bond, and further contains a structure represented by formula (7) and a structure represented by formula (8) between the first and second urethane bonds. By containing these structures in the urethane resin, the crystallinity of the polymer main chain is suppressed even if the molecular weight between crosslinking points is large, and the inhibition of ion migration, particularly at low temperatures, is more easily suppressed. Therefore, the ionic conductivity and rate characteristics are likely to be improved. The method for producing such a urethane resin is not particularly limited, but it can be produced, for example, by using a polyethylene glycol-propylene glycol copolymer as a polyol and reacting it with an isocyanate compound. Alternatively, it can be produced by reacting a urethane prepolymer obtained by reacting a polyethylene glycol-propylene glycol copolymer with an isocyanate compound as the isocyanate compound with a polyol. [ka] [ka]

[0056] It is more preferable that the urethane resin contains a structure represented by the following formula (9). When the urethane resin contains the structure represented by the following formula (9), the crystallinity of the polymer main chain is suppressed, and the inhibition of lithium ion migration, particularly at low temperatures, is more easily suppressed. As a result, the ionic conductivity and rate characteristics are more likely to be improved. [ka] In formula (9), m and n are the average number of moles added, and each independently represents a natural number of 1 or more, satisfying n≦m≦9n. m is preferably 1 to 110, and more preferably 34 to 102. n is preferably 1 to 55, and more preferably 5 to 43. The structure represented by formula (9) can be obtained, for example, by using a polyether polyol obtained by ring-opening polymerization of ethylene oxide and propylene oxide. In addition, the arrangement of the ethylene oxide structure represented by (-CH-CH-O-) and the propylene oxide structure represented by (-CH-CH(CH)-O-) in formula (9) may be a block copolymer or a random copolymer, preferably a random copolymer.

[0057] The structure of the resin can be identified by using known analytical techniques such as pyrolysis GC / MS, TF-IR, and NMR, either alone or in combination. To identify the conductive resin in contact with the inner surface of the active material particles or the conductive resin in contact with the outer surface of the active material particles, known techniques capable of mapping the composition, interatomic bonds, crystalline structure, etc. can be used to replace or supplement the above-mentioned techniques. For example, viscoelasticity mapping using cross-sectional SPM, elemental mapping using TOF-SIMS, carbon-carbon bond mapping using FT-IR or Raman, and soft tissue structural mapping using a soft X-ray microscope can be used. For soft X-ray microscopes, inspection equipment attached to synchrotron radiation facilities such as SPring-8 can be used.

[0058] (anionic structure) Examples of anions that the conductive resin preferably contains include fluoroalkylsulfonylimide anions, fluorosulfonylimide anions, fluoroalkylsulfonate anions, fluorosulfonate anions, fluoroalkylcarboxylate anions, fluoroalkylmethide anions, fluoroborate anions, fluorophosphate anions, dicyanamide anions, thiocyanate anions, and bisoxalatoborate anions. Examples of suitable anions include perchlorate anion, perchlorate anion, and derivatives thereof.

[0059] Specific examples of the fluoroalkylsulfonylimide anion include fluoroalkylsulfonylimide anions having a fluoroalkyl group having from 1 to 6 carbon atoms, such as bis(trifluoromethanesulfonyl)imide anion, bis(pentafluoroethanesulfonyl)imide anion, bis(heptafluoropropanesulfonyl)imide anion, bis(nonafluorobutanesulfonyl)imide anion, bis(dodecafluoropentanesulfonyl)imide anion, and bis(perfluorohexanesulfonyl)imide anion, and cyclic fluoroalkylsulfonylimide anions such as N,N-hexafluoropropane-1,3-disulfonylimide.

[0060] A specific example of the fluorosulfonylimide anion is a bis(fluorosulfonyl)imide anion. Specific examples of the fluoroalkylsulfonate anion include trifluoromethanesulfonate anion, fluoromethanesulfonate anion, perfluoroethanesulfonate anion, perfluoropropanesulfonate anion, perfluorobutanesulfonate anion, perfluoropentanesulfonate anion, perfluorohexanesulfonate anion, and perfluorooctanesulfonate anion. Specific examples of the fluoroalkyl carboxylate anion include a trifluoroacetate anion, a perfluoropropionate anion, a perfluorobutyrate anion, a perfluorovalerate anion, and a perfluorocaproate anion. Specific examples of the fluoroalkyl methide anion include fluorinated alkylsulfonyl methide anions such as tris(trifluoromethanesulfonyl)methide anion, tris(perfluoroethanesulfonyl)methide anion, tris(perfluoropropanesulfonyl)methide anion, tris(perfluorobutanesulfonyl)methide anion, tris(perfluoropentanesulfonyl)methide anion, tris(perfluorohexanesulfonyl)methide anion, and tris(perfluorooctanesulfonyl)methide anion.

[0061] A specific example of the fluoroborate anion is tetrafluoroborate anion. A specific example of the fluorophosphate anion is hexafluorophosphate anion.

[0062] Among these anions, at least one selected from the group consisting of a fluoroalkylsulfonylimide anion, a fluorosulfonylimide anion, a fluoroborate anion, a dicyanamide anion, and a thiocyanate anion is particularly preferred because it reduces the decrease in conductivity in a low-temperature environment.

[0063] The conductive resin preferably has higher flexibility than the active material particles. When the conductive resin has higher flexibility than the active material particles, it is more likely to change shape in response to the expansion and contraction of the active material particles during charging and discharging. As a result, it becomes easier to suppress a decrease in ionic conductivity and electronic conductivity. The fact that the conductive resin has higher flexibility than the active material particles can be confirmed by measuring the Young's modulus using a commercially available device such as a nanoindenter.

[0064] The conductive aid is not particularly limited, and examples thereof include graphite such as natural graphite and artificial graphite, carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black, carbon fluoride powder, conductive fibers such as carbon fiber, carbon nanotube, and metal fiber, metal powder such as gold, platinum, silver, and aluminum, conductive whiskers such as zinc oxide, conductive metal oxides such as titanium oxide, and phenylene oxide. Organic conductive materials such as silicon dielectrics can be used.

[0065] The supporting electrolyte is not particularly limited, and for example, a conductive resin can be used as an organic electrolyte, and an inorganic electrolyte such as a lithium salt can also be used. In addition, ion-conductive solids commonly used in all-solid-state batteries can be used. Examples include Li-B oxide-based solid electrolyte particles, Li-Yb oxide-based solid electrolyte particles, Nasicon-type solid electrolyte particles (LiAlTi(PO4)3, LiAlGe(PO4)3, etc.), and Li-PO-based solid electrolyte particles (Li3PO4, LiPON (particles in which part of the O in Li3PO4 is replaced with N)). Among the above solid electrolyte particles, Li-B oxide-based solid electrolyte particles and Li-Yb oxide-based solid electrolyte particles can be sintered at relatively low temperatures (700°C or less), thereby suppressing reaction with positive electrode active material particles during sintering and maintaining ion conductivity. For this reason, among the above solid electrolyte particles, it is preferable to use Li-B oxide-based solid electrolyte particles and Li-Yb oxide-based solid electrolyte particles.

[0066] The supporting electrolyte is more preferably a lithium salt, such as at least one selected from the group consisting of LiClO4, LiBF4, LiPF6, LiAlCl4, LiSbF6, LiSCN, LiCF3SO3, LiAsF6, lower aliphatic lithium carboxylate, LiCl, LiBr, LiI, lithium chloroborane, lithium tetraphenylborate, LiN(CF3SO3)3, and LiN(C2F5SO2)2. Among these, at least one selected from the group consisting of LiN(CF3SO3)3, LiN(C2F5SO2)2, and LiClO4 is preferred. These lithium salts have high chemical stability with respect to lithium-based active materials, and are less likely to produce an insulating coating at the negative electrode interface due to decomposition of the lithium salt. Therefore, the resistance at the negative electrode interface is less likely to fluctuate. The lithium salts can be used alone or in combination of two or more.

[0067] The content of the supporting electrolyte is preferably 0.8 to 40.0 parts by mass, more preferably 5.0 to 40.0 parts by mass, even more preferably 5.0 to 15.0 parts by mass, and particularly preferably 5.0 to 10.0 parts by mass, relative to 100 parts by mass of the conductive resin. When the content of the supporting electrolyte is within this range, the supporting electrolyte is easily miscible with the conductive resin, does not precipitate even at low temperatures, and high ionic conductivity is obtained. The type and content of indicator electrolyte contained in the conductive resin can be measured by solvent extraction followed by LC-MS or the like.

[0068] The solid electrolyte particles may be commercially available products or may be separately prepared as materials. As the Li-B oxide-based solid electrolyte particles, for example, Li3BO3 (manufactured by Toshima Manufacturing Co., Ltd.) or particles in which part of the O in Li3BO3 is replaced with C can be used. Furthermore, as the Li-Yb oxide-based solid electrolyte particles, for example, Li 5.9 Yb 0.81 La 0.09 Zr 0.1 (BO3)3, etc. can be used.

[0069] In the case of an electrode containing an inorganic electrolyte between active material particles, it is preferable that the region between the active material particles containing the conductive resin overlaps with the region between the active material particles containing the inorganic electrolyte. This overlap between the active material particles between the region between the active material particles containing the conductive resin and the region between the active material particles is also referred to as the conductive resin and the inorganic electrolyte being coexisting unevenly. It is more preferable that the region containing the conductive resin includes a region containing the inorganic electrolyte. The above-mentioned relationship between the conductive resin and the inorganic electrolyte has the effect of reducing the interfacial resistance between the inorganic solid electrolyte particles. Generally, the solid electrolyte (bulk) has better ionic conductivity than the conductive resin. This tends to cause a decrease in conductivity due to the interfacial resistance between the polymer particles. The overlap of the conductive resin with the region containing the solid electrolyte particles facilitates the realization of a low-resistance electrode without significantly reducing the high ionic conductivity of the solid electrolyte (bulk). Furthermore, the above-mentioned relationship can be confirmed by the results of elemental mapping in cross-sectional observations, which will be described later.

[0070] <Method of manufacturing electrode precursor> An example of a method for manufacturing an electrode precursor will be described in detail below with reference to the drawings. Hereinafter, the electrode precursor can be made into a positive electrode precursor by using positive electrode active material particles as the active material particles. Also, the electrode precursor can be made into a negative electrode precursor by using negative electrode active material particles as the active material particles.

[0071] The method for producing an electrode precursor according to the present disclosure preferably includes the following four steps (step 1, step 2, step 3, and step 4): Figure 1 is a conceptual diagram showing the method for producing an electrode precursor. (1) A first step (S101 in FIG. 1) of forming a particle layer containing active material particles and electrolyte particles on a resin substrate having an adhesive portion. (2) A second step (S102 in FIG. 1) of forming a laminate by laminating a plurality of resin substrates (hereinafter also referred to as substrates) on which the particle layer is formed. (3) A third step (S103 in FIG. 1) of removing the resin substrate from the laminate and forming a three-dimensional object containing active material particles and electrolyte particles. (4) A fourth step of post-processing the three-dimensional object (S104 in FIG. 1).

[0072] (1st step) The first step is to form a particle layer containing active material particles and electrolyte particles on a resin substrate having an adhesive portion. In the first step, particles are arranged on the resin substrate using a particle arrangement device, thereby forming the particle layer. Hereinafter, particle arrangement devices 1 and 2 that can be used will be described in order.

[0073] [Particle placement device 1] 2 is a diagram schematically showing the configuration of the particle arrangement device 1. Hereinafter, first particles P1 refer to the above-mentioned active material particles, and second particles P2 refer to the above-mentioned electrolyte particles. The particle placement device 1 has a first storage container 21a that stores and supplies a first base material 11a, a first belt device 22a that transports the first base material 11a, and a pattern forming device 23 that forms a concave-convex pattern on the first base material 11a. The particle placement device 1 also has a first filling device 24a that places first particles P1 in the concaves of the concave-convex pattern formed on the first base material 11a. The particle arrangement device 1 has a second storage container 21b that stores and supplies the second substrate 11b, and a second belt device 22b that transports the second substrate 11b. The particle arrangement device 1 has a transfer unit 25a in which rollers 223a and 223b of the first belt device 22a and the second belt device 22b, respectively, face each other, and the first particles P1 are transferred from the first substrate 11a to the second substrate 11b in the transfer unit 25a.

[0074] Furthermore, the particle placement device 1 has a second filling device 24b that places second particles P2 in a non-transfer portion on the second substrate 11b. Note that devices that are less relevant to explaining the effects of the present invention, such as a peeling and recovery device that peels and recovers the first substrate 11a from the first belt device 22a after transfer and various cleaning devices, will not be shown in the drawings or described in detail.

[0075] In the particle arrangement device 1, the pattern forming device 23, the first filling device 24a, and the transfer unit 25a can be said to be a first arrangement means for arranging the first particles P1 in a pattern on the resin base material which is the second base material 11b. This can be said to be a second arrangement means for arranging the second particles P2 in areas on the oil base material where the first particles P1 are not arranged.

[0076] Hereinafter, a method for arranging particles on substrate 11 using particle arrangement device 1 will be described in accordance with the flow of each process. First, the first substrate 11a is supplied from the first storage container 21a to the first belt device 22a by a supply means (not shown). When the ultraviolet-curable liquid is applied by a pattern forming device 23 (described later), it is preferable that at least the surface of the first base material 11a is made of a material that has high wettability with the ultraviolet-curable liquid. In addition, it is preferable that the surface of the first base material 11a is smooth.

[0077] The first substrate 11a may be a sheet made of a resin such as polyester that has been subjected to a hydrophilic or lipophilic treatment to match the ultraviolet-curable liquid (water-based or oil-based) to be used. The first substrate 11a may be a substrate that is individually cut out like cut paper, a continuous substrate wound into a roll like roll paper, or a continuous substrate that is alternately folded like continuous paper.

[0078] The first belt device 22a transports the supplied first substrate 11a to a pattern formation position of the pattern forming device 23. The first belt device 22a has drive rollers 221a and 222a, a pressure roller 223a, and a belt-like transport member 224a suspended between them. At this time, the pressure roller 223a is rotated by the drive rollers.

[0079] The conveying member 224a is preferably made of resin or metal, for example, a polyimide resin belt can be used. The drive rollers 221a, 222a are preferably made of metal rollers, for example, stainless steel metal rollers can be used. The pressure roller 223a is preferably made of a soft roller having an elastic layer on its surface, for example, a soft roller having a silicone rubber elastic layer on the surface of a stainless steel core can be used.

[0080] 2, the first belt device 22a is used as a conveying device for conveying the first base material 11a, but a roller device can also be used instead of the belt device. The same applies to the second belt device 22b described later.

[0081] The pattern forming device 23 forms a fine concave-convex pattern on the first substrate 11a that has been transported to the pattern forming position. Methods that can be used to form the concave-convex pattern include UV imprinting, thermal imprinting, UV inkjet printing, printing, and laser etching.

[0082] When the pattern forming device 23 forms a concave-convex pattern by a UV imprint method, the pattern forming device 23 has a coating means for coating an ultraviolet-curable liquid onto the first substrate 11a. The ultraviolet-curable liquid can be, for example, an ultraviolet-curable resin such as ultraviolet-curable liquid silicone rubber. The pattern forming device 23 also has an imprinting means for imprinting a mold having a concave-convex pattern formed on its surface onto the ultraviolet-curable liquid on the first substrate 11a, and a light source for irradiating the ultraviolet-curable liquid with ultraviolet rays. Typically, ultraviolet-curable liquid silicone rubber (PDMS) or resin is used as the ultraviolet-curable liquid, a film mold is used as the mold, and a UV lamp is used as the light source.

[0083] The first filling device 24a fills the first particles P1 with the support material S1 carrying the first particles P1. When P1 is filled into the recesses on the first substrate 11a, the opening diameter (width) of the recesses in the concave-convex pattern on the first substrate 11a is preferably larger than the cumulative 50% particle diameter (median diameter) on a volume basis of the first particles P1. Furthermore, the opening diameter (width) of the recesses is preferably smaller than the average size of the support material S1. Here, the opening diameter of the recesses in the concave-convex pattern is preferably the opening diameter in the short-side direction of the recesses, and more preferably the maximum opening diameter in the short-side direction of the recesses. The width of the recesses can be adjusted appropriately depending on the particle sizes of the first particles P1 and the support material S1, etc. The width of the recesses is not particularly limited, but is preferably 0.2 to 30 μm, and more preferably 2 to 15 μm, for example.

[0084] By setting the opening diameter of the recesses of the concave-convex pattern as described above, the first particles P1 can contact the bottoms and side surfaces (typically the bottom surfaces) of the recesses of the concave-convex pattern. On the other hand, the support material S1 cannot contact the bottoms and side surfaces of the recesses. This allows the first particles P1 that contact the bottoms and side surfaces of the recesses to be captured by the concave-convex pattern, while preventing the support material S1 from being captured by the concave-convex pattern. In other words, it is preferable that the first particles P1 can contact the bottoms and side surfaces of the recesses of the concave-convex pattern, but the first support material S1 cannot contact the bottoms and side surfaces of the recesses of the concave-convex pattern.

[0085] Although the pattern forming device 23 forms a concave-convex pattern on the first substrate 11a, a substrate on whose surface a concave-convex pattern has been previously formed may be used as the first substrate 11a. Alternatively, the pattern forming device 23 may form a concave-convex pattern directly on the surface of the conveying member 224a of the first belt device 22a, or a conveying member having a concave-convex pattern on its surface may be used as the conveying member 224a. In this case, in consideration of durability, it is preferable to use a metal belt made of stainless steel, aluminum, or the like, and form the concave-convex pattern on the surface by a microfabrication technique such as laser etching, wet etching, or dry etching.

[0086] The first base material 11a having the concave-convex pattern formed on its surface is transported by the first belt device 22a to the filling position of the first filling device 24a. 3 is a diagram showing a schematic configuration of the filling device. The configuration of the first filling device 24a will be described below, but the same applies to the second filling device 24b.

[0087] The first filling device 24a has a filling container 242a that contains a filler 241a, an agitating screw member 243a that agitates and conveys the filler 241a, a recovery member 244a that recovers the filler, and a magnetic member 247a.

[0088] The filler 241a includes first particles P1 and a support material S1 that supports the first particles P1. The filler 241a is a mixture of multiple powders, including a powder composed of multiple first particles P1 and a powder composed of multiple support materials S1. The filler 241a contained in the filling container 242a is thoroughly mixed when stirred and transported by the stirring screw member 243a. As a result, the first particles P1 are supported on the surface of the support material S1. The forces acting between the particles when they are supported include electrostatic forces due to frictional charging and the like, as well as van der Waals forces and liquid bridging forces.

[0089] The support material S1 is a magnetic particle. The support material S1 is preferably a particle in which the surface of a resin particle in which ferrite core particles or a magnetic substance is dispersed is coated with a resin composition. For example, a standard carrier (Standard Carrier P02 manufactured by the Imaging Society of Japan), which is a magnetic particle, can be used. The particle size and material of the support material S1 are appropriately selected according to the particle size and material of the first particles P1. This allows the first particles P1 to be stably supported. Furthermore, even if the first particles P1 have a small particle size and tend to aggregate, the support material S1 plays a role in loosening the particles by stirring and transporting them. The particle size of the support material S1 can be adjusted appropriately by changing the size (area, width, depth) of the recesses. For example, the volume-based cumulative 50% particle size (median diameter) is preferably 50 to 100 μm.

[0090] Recovery member 244a has roller 245a rotatable in the direction of arrow d2 in the figure, and magnet 246a arranged inside roller 245a and fixed to filling container 242a. Magnetic member 247a is arranged opposite filling container 242a via conveying member 224a, and has magnet 248a inside.

[0091] Magnet 246a has a plurality of N poles and S poles arranged alternately along the rotation direction of collection member 244a. Magnet 248a has a plurality of N poles and S poles arranged alternately along the conveying direction of conveying member 224a. Magnet 246a also has a magnetic pole (N1 pole in FIG. 3) of a different polarity at a position closest to and facing the most downstream magnetic pole (S1 pole in FIG. 3) of magnet 248a, and an N2 pole of the same polarity as the N1 pole is arranged at the most downstream position. The magnet 246a and the magnet 248a may be composed of a plurality of magnets, and the type of magnet constituting the magnet 246a and the magnet 248a is not particularly limited. For example, a permanent magnet such as a rare earth magnet, a ferrite magnet, a neodymium magnet, or a samarium-cobalt magnet, or a plastic magnet, or a means for generating a magnetic field such as an electromagnet can be used. The magnet 248a may be configured to be movable in the transport direction of the first substrate 11a or in the opposite direction.

[0092] Note that a regulating member for regulating the filler 241a on the first base material 11a or a collecting member for re-collecting the filler 241a that cannot be collected by the collecting member 244a may be provided upstream or downstream of the collecting member 244a in the transport direction of the transport member 224a. The collecting member for re-collecting the filler 241a may be a member similar to the collecting member 244a, or may be a simple member such as a fixed magnet or a regulating member, or a collecting member that performs collection by air blowing.

[0093] Next, the process of filling the recesses on the first substrate 11a with the first particles P1 by the first filling device 24a will be described with reference to FIGS. As the first conveying member 224a moves in the direction of the solid arrow d1 in Figure 3, the first base material 11a carried and conveyed by the first conveying member 224a is conveyed and conveyed to the filling position of the first filling device 24a.

[0094] Filler 241a is transported by stirring screw member 243a and supplied onto first substrate 11a (dotted line a in FIG. 3). At this time, a magnetic field is formed by magnetic member 247a and recovery member 244a, and filler 241a containing magnetic particle carrier material S1 forms multiple magnetic chains on first substrate 11a due to the magnetic field. Filler 241a supplied onto first substrate 11a is transported on first substrate 11a while forming magnetic chains as first substrate 11a moves (dotted line b in FIG. 3).

[0095] Figures 4A, 4B, and 4C are schematic diagrams of filler 241a being transported on the first substrate 11a. For illustrative purposes, filler 241a other than the filler forming a single magnetic strand are omitted from the illustration. As described above, filler 241a on the first substrate 11a forms magnetic strands along the magnetic field lines of the generated magnetic field. As the first substrate 11a moves, the magnetic strands change shape as the filler is transported, as shown in Figures 4A, 4B, and 4C. Because a particularly strong magnetic force acts near magnet 248a, the transport speed v2 of filler 241a is smaller than the transport speed v1 of the first substrate 11a when filler 241a moves away from the magnetic pole, and is larger when filler 241a moves away from the magnetic pole. In other words, filler 241a on the first substrate 11a has a non-zero relative speed with respect to the first substrate 11a.

[0096] 5 is an enlarged view of the vicinity of the surface of the first base material 11a in FIGS. 4A to 4C. Although not shown in FIGS. 4A to 4C, as shown in FIG. 5, the first base material 11a has a concave-convex pattern 1. The concave-convex pattern can be formed as a desired pattern such as a honeycomb pattern or a line pattern. The filler 241a comes into contact with the concave-convex pattern 111a, and is transported together with the first substrate 11a while maintaining a non-zero relative speed with respect to the first substrate 11a while being subjected to a magnetic force (solid line Fm in the figure) in a direction perpendicular to the surface of the first substrate 11a. As a result, the first particles P1 carried on the support material S1 are transported while being rubbed against the concave-convex pattern 111a on the surface of the first substrate 11a.

[0097] At this time, the particle size of the first particles P1 is smaller than the opening diameter of the recesses of the uneven pattern 111a, and the particle size of the first support material S1 is larger than the opening diameter of the recesses, so the first particles P1 can contact the bottom surfaces (bottoms) and side surfaces of the recesses of the uneven pattern 111a, but the support material S1 cannot. In other words, only the first particles P1 in the filler 241a selectively contact the bottom surfaces and side surfaces of the recesses.

[0098] The first particles P1 that come into contact with the recesses are strongly restrained by a physical restraining force due to the structure of the concave-convex pattern 111a and by non-electrostatic adhesive forces such as electrostatic adhesive forces and adhesive forces with the structural materials that make up the first base material 11a and the concave-convex pattern 111a, and are detached from the support material S1. Note that, for the sake of explanation, in Fig. 5, the first particles P1 are supported on the surface of the support material S1, but it is acceptable for particles P1 that are not supported on the support material S1 to exist during the agitation, supply, or transport of the filler 241a.

[0099] Downstream of the magnetic member 247a, the recovery member 244a is disposed with a gap between it and the first transport member 224a, as shown in Fig. 3. As the first base material 11a moves, the filler 241a is transported to the vicinity of the most downstream magnetic pole (pole S1) of the magnet 248a. Under the influence of the magnetic field formed by the magnet 246a, the filler 241a moves from the first base material 11a to the recovery member 244a and is recovered (dotted line c in Fig. 3).

[0100] As described above, during the transport process (dotted lines a, b, and c in FIG. 3), the recesses of the concave-convex pattern 111a on the surface of the first base material 11a are in sufficient contact with the plurality of fillers 241a. Therefore, after the fillers 241a are collected by the collection member 244a, the first particles P1 are selectively and densely arranged in the recesses of the concave-convex pattern 111a.

[0101] 4A to 4C and 5, the first particles P1 are all shown with the same particle size, but in reality there is a particle size distribution, and depending on the material, the particles may form aggregated secondary particles. Furthermore, the particles may not be spherical as shown. Even in such cases, only particles that can contact the recesses of the uneven pattern 111a are selectively and densely packed, so coarse powder and secondary particles that may adversely affect the particle placement process are easily excluded.

[0102] In this way, the amount of the first particles P1 filled into the recesses of the concave-convex pattern 111a can be controlled by the size (area, width, depth) of the concave-convex pattern and the particle size of the first particles P1. Specifically, the area of ​​the recesses is approximately the filling area, and the layer thickness of the filled first particles P1 is determined by the depth of the recesses. The pitch of the convex portions is not particularly limited, but is preferably, for example, 1.0 to 20 μm, and more preferably 2.0 to 15 μm. The height of the convex portions is not particularly limited, but is preferably, for example, 0.1 to 20.0 μm, and more preferably 1.0 to 10.0 μm. The area ratio of the recesses (the ratio of the recesses to the area of ​​the recessed / protruding pattern) is not particularly limited, but is preferably, for example, 50% or more, and more preferably 70% or more.

[0103] For example, to obtain a thin layer (single layer) that is 50% of the substrate area, the area ratio of the recesses (concave and recess pattern) The area ratio of the recesses to the entire turn should be 50%, and the depth of the recesses should be equal to or smaller than the particle size of the first particles P1. In this case, the opening width of the recesses should be larger than the median diameter of the first particles P1 and smaller than the average size (here, the average particle size) of the support material S1.

[0104] Although the first particles P1 may have a wide particle size distribution (broad particle size distribution), the support material S1 preferably has a narrow particle size distribution, and is more preferably monodisperse. This makes it easier to prevent the support material S1 from contacting the bottom (or bottom surface) or side surfaces of the recess. If the support material S1 can contact the bottom or side surfaces of the recess, the support material S1 may also be restrained and filled in the recess.

[0105] Furthermore, the opening width of the recesses of the concave-convex pattern 111a is preferably smaller than four times the particle diameter of the first particles P1. By making the opening width smaller than four times the particle diameter of the first particles P1, the probability that the first particles P1 will come into contact with two points, the bottom and side surfaces of the recesses of the concave-convex pattern 111a, can be increased. In this way, the first particles P1 that come into contact with the concave-convex pattern 111a at multiple points are strongly constrained by the concave-convex pattern 111a, and therefore the efficiency of filling the concave-convex pattern 111a with the first particles P1 can be increased. The same applies to the particle size of the second particles P2 described later and the size of the recesses of the uneven pattern formed by the first particles P1 on the second base material. Also, when brush fibers are used as the support material, the "average particle size of the support material" in the above explanation becomes the "average fiber diameter of the support material."

[0106] Filler 241a collected by collection member 244a is transported by roller 244a, which is a rotating collection member (dotted line d in FIG. 3). Filler 241a transported by roller 244a falls into filling container 242a due to the influence of gravity and the magnetic field generated by two adjacent, repelling magnetic poles (N1, N2) of the same polarity (dotted line e in FIG. 3). Thereafter, filler 241a is again stirred and transported by stirring screw member 243a, and this process is repeated thereafter.

[0107] The weight ratio of the first particles P1 to the support material S1 in the filler 241a in the filling container 242a is determined by an inductance sensor that measures magnetic permeability, a patch density sensor that measures and predicts the reflection density on a substrate, or the like, which are common in electrophotographic devices. Then, at least one of the first particles P1 and the support material S1 is replenished by a replenishment means (not shown) as needed. This allows stable filling over a long period of time. The mass % of the first particles P1 in the filler 241a is not particularly limited, but is preferably in the range of 5 to 40 mass %, or 10 to 30 mass %.

[0108] Although the filling device described here uses magnetic particles as a carrier material to form a magnetic brush, filling the recesses with the particulate material, the filling device method is not limited to this. Brush fibers can also be used as the carrier material. Alternatively, an elastic material, at least the surface of which is made of an elastic body, can also be used as the carrier material.

[0109] FIG. 6A is a diagram schematically illustrating the configuration of a filling device 24c when brush fibers are used as the support material. The filling device 24c has a roller 2410 with brush fibers on its surface. The roller 2410 is a so-called brush roller, with brush fibers planted on its surface. The material of the fibers constituting the brush fibers of the roller 2410 can be, for example, nylon, rayon, acrylic, vinylon, polyester, vinyl chloride, or the like. The surface of the fibers may be subjected to a surface treatment in order to adjust the electrostatic charge property or rigidity.

[0110] The filling device 24c has a supply member that supplies the filler 241a to the roller 2410. The filler 241a contains powder including the first particles P1, and is contained in a filling container 242a. In this example, the filler 241a does not include the support material S1, which is magnetic particles. The filler 241a is stirred and conveyed by the stirring screw member 243a and supplied to the supply member 249.

[0111] The supply member 249 is a member that supplies the filler 241a to the roller 2410, and its configuration is not particularly limited. For example, the supply member 249 can be a roller whose surface is made of an elastic, porous foam material. Typically, an elastic sponge roller having a foamed skeleton structure and having a relatively low hardness polyurethane foam formed on a core metal can be used. Note that, in addition to urethane, various rubber materials such as nitrile rubber, silicone rubber, acrylic rubber, hydrin rubber, and ethylene propylene rubber can be used as the foam material.

[0112] The supplied filler 241a is filled into the foam material on the surface of the supply member 249 and is transported to a supply section that comes into contact with the roller 2410. In the supply section, the filler 241a filled into the foam material is charged by contact with the brush fibers of the roller 2410 and is carried by the brush fibers of the roller 2410. Furthermore, the supply member 249 may also have a function of peeling off and refreshing the filler 241a remaining on the roller 2410. The filler 241a supplied to the roller 2410 comes into contact with the first substrate 11a as the brush fibers move.

[0113] At this time, the first particles P1 in the filler 241a can come into contact with the bottom and side surfaces of the recesses of the uneven pattern 111a on the surface of the first substrate 11a, but the brush fibers cannot. In other words, the fiber diameter of the brush fibers is set to be larger than the opening width of the recesses of the uneven pattern 111a. The fiber diameter of the brush fibers can be measured by placing a glass on the surface of the roller 2410 and taking an image of the brush fibers through the glass using an optical microscope. At this time, the fiber diameters of approximately 100 brush fibers are measured, the fiber diameter distribution is measured, and the average diameter is calculated.

[0114] The movement of the transport member 224a and the rotation of the roller 2410 cause the brush fibers of the roller 2410 to rub against the surface of the first base material 11a, so that the first particles carried by the brush fibers are densely arranged in the recesses of the uneven pattern 111a on the surface of the first base material 11a.

[0115] FIG. 6B is a diagram schematically illustrating the configuration of a filling device 24d when an elastic material is used as the support material. Filling device 24d has a similar configuration to filling device 24c, but differs in that it uses roller 2411 having an elastic material instead of roller 2410 having brush fibers. Roller 2411 is a roller with an elastic layer formed on its surface.

[0116] The elastic layer is formed of an elastic material such as a rubber material such as silicone rubber, acrylic rubber, nitrile rubber, urethane rubber, fluororubber, etc. The surface shape of the elastic layer may be controlled by adding fine particles such as spherical resin. When the elastic layer has convex portions on its surface, the size of the convex portions of the elastic layer is set larger than the size of the concave portions of the concave-convex pattern 111 a. The size of the convex portions of the elastic layer can be measured in the same manner as the fiber diameter of the brush fibers described above.

[0117] The movement of the transport member 224a and the rotation of the roller 2411 causes the elastic material on the surface of the roller 2411 to rub against the surface of the first base material 11a, so that the first particles carried by the elastic material are densely arranged in the recesses of the concave-convex pattern 111a on the surface of the first base material 11a.

[0118] By using brush fibers or elastic materials as the carrier material as shown in Figures 6A and 6B, it is not necessary to include magnetic particles in the filler. Furthermore, the configuration of the filling device can be simplified. On the other hand, when magnetic particles are used as the carrier material as shown in Figure 3, there is greater freedom in the size and shape of the carrier material than when using brush fibers or elastic materials. Furthermore, magnetic particles allow greater freedom in the movement of the carrier material on the substrate.

[0119] For these reasons, when magnetic particles are used as the support material, particles such as the first particles P1 can be more efficiently supplied onto the substrate, and recesses on the substrate can be more efficiently filled. Also, when a magnetic material is used as the support material, even if the support material deteriorates during the process, it can be replenished or replaced without stopping the process.

[0120] The method of filling the recesses with particles by rubbing a support material carrying the particles allows a larger amount of dispersed particles to be supplied to the recesses, and allows for stable and dense filling, compared to a filling method using a restricting member such as a blade. This advantage is more pronounced as the particle size of the particles to be filled becomes smaller, since the particles tend to aggregate more easily.

[0121] The first base material 11a, in which the recesses of the concave-convex pattern 111a have been filled with the first particles 1 by the first filling device 24a, is transported to the transfer unit 25a by the first belt device 22a. 2, the second belt device 22b, like the first belt device 22a, has drive rollers 221b and 222b, a pressure roller 223b, and a belt-like conveying member 224b suspended between them. At this time, the pressure roller 223b is driven to rotate. At the transfer section 25a, the pressure roller 223a of the first belt device 22a and the pressure roller 223b of the second belt device 22b face each other.

[0122] The second substrate 11b is supplied from the second storage container 21b to the second belt device 22b and transported in the direction of the arrow in Fig. 2. The supplied second substrate 11b is transported in synchronization with the transport of the first substrate 11a to the transfer unit 25a. In the transfer unit 25a, the first particles P1 filled in the first substrate 11a are transferred to the second substrate 11b.

[0123] That is, the first substrate 11a can also be referred to as a transfer substrate for transferring the first particles P1 to the second substrate 11b. The concave-convex pattern formed on the surface of the first substrate 11a can also be referred to as a transfer concave-convex pattern. This transfer process will be described below with reference to FIG. 7.

[0124] 7 is a diagram showing a schematic configuration of the transfer unit 25a. The transfer unit 25a is composed of the pressure roller 223a and the conveying member 224a of the first belt device 22a, and the pressure roller 223b and the conveying member 224b of the second belt device 22b. As described above, the pressure rollers 223a and 223b rotate drivenly, and the two rollers are in contact with each other via the conveying members 224a and 224b. At least one of the pressure rollers 223a and 223b is a soft roller having an elastic layer on its surface, and a nip is formed where the two rollers contact each other.

[0125] The first substrate 11a, which has been filled with the first particles P1 by the first filling device 24a, and the second substrate 11b are transported at approximately the same speed by their respective transport members (224a, 224b) and enter a nip formed by contact between the pressure rollers 223a, 223b. In the nip, the first particles P1 on the first substrate 11a come into contact with the second substrate 11b and are transferred onto the second substrate 11b.

[0126] The adhesive force of the second substrate 11b to the first particles P1 is greater than that of the first particles P1 of the first substrate 11a. The adhesive force of the first particles P1 to the second substrate 11b is greater than the adhesive force of the first particles P1 to the first substrate 11a. In other words, the adhesive force of the first particles P1 to the second substrate 11b is greater than the adhesive force of the first particles P1 to the first substrate 11a. As a result, the first particles P1 on the first substrate 11a are transferred onto the second substrate 11b at the nip portion.

[0127] The material of the second substrate 11b is not particularly limited, and a substrate of the same material as the first substrate 11a can be used. Note that, like the first substrate 11a, the second substrate 11b may be a substrate that is individually cut like cut paper, a continuous substrate that is wound into a roll like roll paper, or a continuous substrate that is alternately folded like continuous paper.

[0128] The second substrate 11b is preferably subjected to a surface treatment to enhance adhesive strength in order to transfer the contacted first particles P1. For example, the second substrate 11b preferably has an adhesive portion on its surface where an adhesive is applied. As a preparation step for preparing a resin substrate having an adhesive portion, for example, the second substrate 11b is prepared. The thickness of the second substrate is not particularly limited, but is preferably, for example, 1 to 10 μm. Furthermore, the thickness of the adhesive portion is not particularly limited, but is preferably, for example, 0.1 μm or more, and more preferably 0.5 μm or more.

[0129] Furthermore, the back surface of the second substrate 11b (the surface to which the first particles P1 are not transferred) also preferably has an adhesive portion coated with the same adhesive as the front surface, and the front surface is further preferably covered with a protective film or the like. This prevents the substrates from shifting when stacked as described below, and also secures the active material particles and electrolyte particles between the substrates by sandwiching them between the top and bottom surfaces (stacking direction). This prevents particle movement during stacking, storage of the stack, heat treatment, and pressure application, allowing the desired electrode precursor to be formed.

[0130] The adhesive is not particularly limited, and may be an acrylic adhesive, a rubber adhesive, a silicone adhesive, or a thermoplastic resin or a photocurable resin whose adhesive strength changes in response to disturbances such as heat or light. The particle arrangement device 1 may also have application means such as a dispenser or an inkjet head that applies an adhesive to the surface of the second substrate 11b during transportation. The type and amount of adhesive to be applied are adjusted as appropriate depending on the shape and material of the concave-convex pattern to be used, and the particle size and material of the first particles P1 and second particles P2, but it is preferable that the adhesive has a stronger adhesive strength than the concave-convex pattern 111a. The adhesive strength can be compared by a general method using a nanoindenter.

[0131] At the nip portion, the first particles P1 are restrained by the adhesive force generated between the first particles P1 and the second substrate 11b. When the conveying members 224a and 224b pass through the nip portion and are separated from each other, the first particles P1 that were on the first substrate 11a are transferred to the second substrate 11b.

[0132] The second substrate 11b onto which the first particles P1 have been transferred is transported by the transport member 224b to the loading position of the second loading device 24b. The second filling device 24b has the same configuration and function as the first filling device 24a, except that a filling material 241b having second particles P2 and a carrier material S2 is contained in the filling container 242a instead of the filling material 241a having first particles P1 and a carrier material S1.

[0133] The second filling device 24b fills the second particles P2 into the portions of the second substrate 11b where the first particles P1 are not placed. As described above, the first particles P1 are placed on the second substrate 11b that has passed through the transfer unit 25a, but the adhesive portion is exposed in the portion where the first particles P1 are not placed, and a recess is formed, so to speak. The second filling device 24b fills the second particles P2 into this recess (adhesive portion) in the same process as the first filling device 24a. .

[0134] In this way, the fillable second particles P2 are selectively filled into gaps on the second base material 11b where the first particles P1 are not arranged, thereby improving the coverage of the base material by the particles. The second particles P2 preferably have a median diameter equal to or smaller than the opening width of the gaps between the first particles P1. Note that, although the case where magnetic particles are used as the carrier material will be described here, brush fibers or elastic material may also be used as the carrier material, as in the first filling device 24a.

[0135] The filler 241b includes second particles P2 and a support material S2 that supports the second particles P2. The filler 241b is a mixture of multiple powders including a powder composed of multiple second particles P2 and a powder composed of multiple support materials S2. The support material S2 may be the same as or different from the support material S1. The support material S2 is selected appropriately depending on the particle size and material of the second particles P2 and the opening width of the voids described above. The mass % of the second particles P2 in the filler 241b is not particularly limited, but is preferably in the range of 5 to 40 mass %, or 10 to 30 mass %.

[0136] FIG. 8 is an enlarged view of the surface of the second substrate 11b during the filling process using the second filling device 24b. A concave-convex pattern is formed on the second substrate 11b, including protrusions where the first particles P1 are disposed and recesses where the first particles P1 are not disposed. The adhesive portions 13b are exposed in the recesses on the second substrate 11b where the first particles P1 are not disposed. During the filling process using the second filling device 24b, the second particles P2 are disposed on the adhesive portions 13b on the surface of the second substrate 11b. After the filling process using the second filling device 24b, the first particles P1 and the second particles P2 are disposed adjacent to each other on the surface of the adhesive portion of the second substrate 11b. In other words, by disposing the second particles P2 in the portions of the second substrate 11b where the first particles P1 are not disposed, the first particles P1 and the second particles P2 can be disposed adjacent to each other. Furthermore, it is not necessary that the second particles P2 are arranged adjacent to all of the first particles P1, and the first particles P1 or the second particles P2 may be adjacent to each other.

[0137] The filler 241b comes into contact with this concave-convex pattern, and is transported together with the second substrate 11b while maintaining a non-zero relative speed with respect to the second substrate 11b while being subjected to a magnetic force (solid line Fm in the figure) in a direction perpendicular to the surface of the second substrate 11b. As a result, the second particles P2 carried by the support material S2 are transported while being rubbed against the concave-convex pattern on the surface of the second substrate 11b.

[0138] At this time, the opening width of the recesses of the uneven pattern is set to a size that allows the second particles P2 to contact the recesses but prevents the support material S2 from contacting them. That is, the opening diameter of the recesses of the uneven pattern on the second base material 11b is preferably larger than the cumulative 50% particle size (median diameter) in the volume-based particle size distribution of the second particles P2. Furthermore, the opening diameter of the recesses is preferably smaller than the average size of the support material S2. Here, the opening diameter of the recesses of the uneven pattern is preferably the opening diameter in the short side direction of the recesses, and more preferably the maximum opening diameter in the short side direction of the recesses. This allows only the second particles P2 in the filler 241b to selectively contact the recesses.

[0139] The second particles P2 that come into contact with the recesses are strongly bound by the physical binding force due to the structure of the concave-convex pattern, and by the electrostatic adhesion and adhesive force with the second base material 11b and the structural material (here, the first particles P1) that constitutes the concave-convex pattern, and are detached from the support material S2. Note that, for the sake of explanation, in FIG. 8, the second particles P2 are supported on the surface of the support material S2, but it is acceptable for there to be second particles P2 that are not supported on the support material S2 when the filler 241b is stirred, supplied, or transported. stomach.

[0140] 9A is a schematic diagram of the second substrate 11b after the first particles P1 have been transferred by the transfer unit 25a, as viewed from a direction perpendicular to the substrate surface. As shown in FIG. 9A, a honeycomb pattern is formed on the second substrate 11b, in which the first particles P1 are arranged in regular hexagonal regions.

[0141] The first particles P1 are densely arranged within this regular hexagonal region, and the other portions (white areas in FIG. 9A) are free of the first particles P1, leaving the adhesive portions of the surface of the second substrate 11b exposed. The regular hexagonal region in which the first particles P1 are held is referred to as the first pattern portion. The honeycomb pattern region in which the second particles P2 are held and which corresponds to the gaps in the first pattern portion is referred to as the second pattern portion.

[0142] FIG. 9B is a schematic diagram of the second substrate 11b after the second particles P2 have been filled by the second filling device 24b, viewed from a direction perpendicular to the substrate surface. As shown in FIG. 9B, the second particles P2 are densely arranged in the areas where the first particles P1 were not arranged and the adhesive portion was exposed. The first particles P1 and the second particles P2 are also densely arranged at the boundary between the area where the first particles P1 are arranged and the area where the second particles P2 are arranged. Note that particles can also be filled in the small gaps between the first particles P1 using a similar method. In this case, a filler containing particles with a particle size corresponding to the gaps between the first particles P1 can be used to fill the gaps using the same method as described above, thereby forming an even denser thin film.

[0143] Although the first particles P1 and the second particles P2 are placed by one filling device 24a and one filling device 24b, multiple filling devices may be used. This can improve compactness. Furthermore, the particles are not limited to the first particles P1 and the second particles P2, and by adding a filling device, third particles other than the first particles and the second particles can also be placed.

[0144] [Particle placement device 2] 10 is a diagram schematically illustrating the configuration of a particle arrangement device 2. The particle arrangement device 2 is a device that forms a particle layer 12 on a substrate 11, and includes a storage container 21 that stores and supplies the substrate 11, and a belt device 22 that transports the substrate 11. The particle arrangement device 2 may also include a liquid application device 201 that applies a liquid for providing adhesive portions on the substrate 11. In this case, in order to densely arrange the particles on the substrate 11, it is preferable to apply the liquid in a pattern on the substrate 11.

[0145] As the liquid applying device 201, a device that ejects liquid by an inkjet method or a device that applies liquid can be used, but a plate-based method such as a flexographic plate can also be used. Among these, it is preferable to use a device that ejects liquid by an inkjet method as the liquid applying device. As a device for discharging liquid by an inkjet method, devices using various discharging methods, such as a thermal type, a piezo type, an electrostatic type, or a continuous type, can be used.

[0146] The liquid applied by the liquid applying device 201 may be water-based or oil-based, as long as it contains a material to which the first particles P1 can adhere. The liquid is appropriately selected, for example, by selecting a material that does not react with the first particles P1. The liquid applying device 201 may also form the pattern L1 using multiple types of liquid. For example, the liquid applying device 201 may apply two types of liquid that react with each other on the substrate 11 to increase adhesion. Examples of materials to which the first particles P1 can adhere include resins such as acrylic resins.

[0147] The powder applying device 202 applies powder containing the first particles P1 to the substrate 11 on which the liquid has been arranged in a pattern. As a result, the first particles P1 are fixed by the material on the substrate 11, and the particles P1 are fixed in a pattern corresponding to the pattern L1.

[0148] The means for applying the powder by the powder applying device 202 may be a means for spraying or sprinkling the powder toward the substrate 11. The powder applying device 202 may further include a means for removing the first particles P1 that are not fixed to the substrate 11 by means of vibration, centrifugation, air blowing, suction, or the like.

[0149] The particle arrangement device 2 may further include a drying device that evaporates at least a portion of the liquid applied by the liquid application device 201 to control the amount of material on the substrate 11, the thickness of the pattern L1, and the like. This drying device may be provided downstream of the liquid application device 201 and upstream of the powder application device 202. The material on the substrate after drying may be a liquid, a liquid containing solids, or only solids.

[0150] After the first particles P1 are fixedly arranged on the substrate 11, a liquid is applied by a liquid applying device 203 to provide adhesive portions at least in the areas where the first particles P1 were not arranged. The liquid applying device 203 has the same function as the liquid applying device 201. After the liquid is applied to the substrate 11 by the liquid applying device 203, second particles P2 are applied by a second filling device 24. As a result, a dense particle layer 12 is formed on the substrate 11.

[0151] Furthermore, like the particle arrangement device 1, the particle arrangement device 2 may have a transfer unit. In this case, the transfer unit is provided downstream of the powder application device 202. The first particles P1 are transferred from the substrate 11 to another substrate having an adhesive portion. In the substrate to which the first particles P1 have been transferred, the second particles P2 can be arranged using the second filling device 24 in areas where the first particles P1 are not arranged and the adhesive portion is exposed. This makes it possible to arrange the first particles P1 and the second particles P2 densely on the adhesive portion of the resin substrate.

[0152] In the particle arrangement devices 1 and 2, the coverage of the resin substrate by the first particles P1 and the second particles P2 is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more. The coverage of the resin substrate by the first particles P1 and the second particles P2 can be measured by photographing the region where the particle layer is formed using an optical microscope from a direction perpendicular to the substrate, and calculating the area ratio of the first particles P1 and the second particles P2 in that region using image processing software.

[0153] By using the particle arrangement device 1 or particle arrangement device 2 described above, the first particles P1 are arranged on the adhesive portion of the resin substrate in the first step (S101 in FIG. 1), and the second particles P2 are arranged.

[0154] (2nd process) The second step is a step of forming a laminate by stacking a plurality of resin substrates (hereinafter also referred to as substrates) on which particle layers are formed. The number of layers of the laminate is not particularly limited and is determined according to the desired electrode capacity. In addition, the laminate is preferably formed on a current collector such as a positive electrode current collector as a substrate. In other words, the laminate preferably includes a substrate. As the current collector, known current collectors such as Al foil, SUS foil, platinum foil, and gold foil can be used. An electrolyte may also be used as the substrate.

[0155] In this case, the electrolyte may be a separately prepared solid electrolyte sheet or an electrolyte substrate consisting of only electrolyte particles on a similar substrate. Also, a solid electrolyte can be used as the electrolyte. When the electrode is a positive electrode, the solid electrolyte sheet or electrolyte substrate is a positive electrode substrate. A negative electrode or a negative electrode substrate may be formed on the opposite side of the lamination surface.

[0156] 11 is a diagram showing a schematic configuration of the laminate forming apparatus U3. The laminate forming apparatus U3 has a conveying device 31 that conveys the substrate 11 on which the particle layer 12 is formed, and a stage 32 that can be moved back and forth in the vertical direction by an actuator (not shown).

[0157] The conveying device 31 receives the substrate 11 having the particle layer 12 formed using the particle placement device, and conveys it to the stage 32. Examples of the conveying device 31 that can convey the substrate 11 include a belt conveyor, a roller, and a robot arm. When the substrate 11 is transported to the stage 32 by the transport device 31, the stage 32 moves in the vertical direction by an amount equivalent to the thickness of the substrate 11 and the particle layer 12. By repeating the transport by the transport device 31 and the movement of the stage 32, multiple substrates 11, each having a particle layer 12 formed thereon, are stacked, and a laminate 15 is formed.

[0158] In this case, it is preferable that the back surface of the substrate 11 on which the particle layer 12 is formed has an adhesive portion. This adhesive portion allows the substrates to adhere to each other, increasing the strength of the laminate and preventing misalignment between the substrates even after the second step. Furthermore, the particle layer 12 between the substrates is sandwiched between the upper and lower adhesive portions, preventing misalignment during processing or storage of the laminate. The adhesive portion may be applied by a coating device (not shown) before lamination, or a pre-coated substrate may be used and the protective film coated on the coated surface may be peeled off before lamination.

[0159] It is preferable to have a static elimination step of eliminating static electricity from the substrate immediately before forming the laminate 15. The particle layer 12 and substrate 11 formed using the particle placement device are easily charged, and electrostatic repulsion occurs between the substrates when they are laminated. Therefore, when laminating in the second step, the substrates tend to peel off or gaps tend to form between the substrates. In the static elimination step, static electricity is preferably eliminated without contact using an electrostatic elimination blower or the like. Furthermore, after the laminate 15 is formed, it is preferable to have a degassing step of degassing the laminate in order to reduce voids between the substrates. In the degassing step, degassing is preferably performed using a vacuum packaging machine or the like.

[0160] (3rd step) The third step is a step of removing the resin substrate from the laminate to form a three-dimensional object containing active material particles and electrolyte particles. Preferably, the laminate is sintered to remove the resin substrate from the laminate. This allows the active material particles to have inner and outer surfaces. In other words, the third step can be said to be a step of forming inner surfaces on the active material particles, or a step of forming outer surfaces on the active material particles. 12 is a diagram showing a schematic configuration of the sintering apparatus U4, which includes a transfer device 41 for transferring the laminate 15 and a heating furnace 42 for heating the laminate 15.

[0161] The conveying device 41 receives the laminate 15 from the laminate forming device and conveys it to the heating furnace 42. Similar to the conveying device 31, the conveying device 41 is preferably a device capable of conveying the laminate 15. Examples of devices capable of conveying the laminate 15 include a belt conveyor, a roller, and a robot arm.

[0162] The heating furnace 42 is a furnace that heats the laminate 15. The heating furnace 42 has a heating means 421, a pressurizing means 422, and an atmosphere adjusting means 423 (423a and 423b). A firing furnace used for firing ceramics or the like can be used as the heating furnace 42. The pressurizing means 422 pressurizes the laminate 15 being heated in the heating furnace 42, and pressurizes the laminate 15 before and after heating.

[0163] It is preferable that the pressurizing means 422 has a pressurizing portion that pressurizes the laminate 15 formed of a porous material that allows gas to easily pass through. The atmosphere adjusting means 423 has an atmosphere gas supplying means 423a and a pressure reducing means 423b, and adjusts the atmosphere gas in the processing space of the heating furnace 42. As the atmospheric gas, an oxidizing atmosphere (O2), an inert atmosphere (Ar, N2, etc.) or a reducing atmosphere (Ar-H2) can be used, but sintering may also be carried out in air.

[0164] When sintering the laminate, it is preferably heated at a temperature equal to or higher than the thermal decomposition temperature of the substrate 11 in the laminate 15, and preferably at a temperature lower than the thermal decomposition temperature of each particle layer in the laminate 15. The temperature to which the laminate is heated is preferably 200°C or higher and 1000°C or lower, more preferably 400°C or higher and 800°C or lower, particularly preferably 450°C or higher and 800°C or lower, and even more preferably 450°C or higher and 650°C or lower. It is preferable to maintain the sintering temperature for 30 minutes or longer, more preferably 1 hour or longer. There is no particular upper limit, but it may be, for example, 3 hours or shorter, or 2 hours or shorter. For example, it is preferable to maintain the sintering temperature for 30 minutes to 3 hours, or 1 hour to 2 hours. The thermal decomposition temperature is the temperature at which the weight of a material begins to decrease when the temperature is gradually increased in a heating atmosphere in a sintering treatment device. Therefore, by heating the laminate at a temperature equal to or higher than the thermal decomposition temperature of the base material 11, the base material 11 in the laminate can be decomposed, its weight can be reduced, and the base material 11 can be removed from the laminate.

[0165] The heating temperature is preferably equal to or higher than the thermal decomposition temperature of the base material 11, but it is preferable to heat at a temperature even higher than the thermal decomposition temperature. Specifically, when the temperature is increased from room temperature (25°C) at a rate of 5°C / min in an atmosphere (typically air) during heating in a sintering treatment device and thermogravimetric analysis is performed, it is preferable to heat at a temperature equal to or higher than the temperature at which the weight is reduced to 70% of the initial weight. Specifically, for example, 385°C or higher is preferable.

[0166] Similarly, when thermogravimetric analysis is performed, it is more preferable to heat the substrate 11 to a temperature equal to or higher than the temperature at which the substrate 11 loses 50% of its initial weight, and even more preferable to heat the substrate 11 to a temperature equal to or higher than the temperature at which the substrate 11 loses 20% of its initial weight. Specifically, for example, a temperature of 400°C or higher is preferable, and 450°C or higher is more preferable. This can shorten the time required to remove the substrate 11 and increase the removal rate of the substrate 11.

[0167] In this way, when the sintering treatment apparatus removes the base material 11 by heating, it is preferable that the active material particles and the solid electrolyte particles have a higher thermal decomposition temperature than the base material 11. In general, inorganic materials tend to have higher thermal decomposition temperatures than organic materials, so it is preferable that the active material particles and the solid electrolyte particles are inorganic materials and the base material 11 is made of an organic material such as a resin. Furthermore, when the sintering treatment apparatus removes the base material 11 by heating, it is preferable that the active material particles are made of a material having a softening point temperature higher than the thermal decomposition temperature of the base material 11.

[0168] The sintering treatment device preferably removes 90% by weight or more of the resin substrate in the laminate 15 by heating, more preferably removes 95% by weight or more, and even more preferably removes 97% by weight or more. At this time, the resin substrate is preferably burned or gasified and released to the outside as a gas. At this time, when the resin substrate gasified by pyrolysis is released to the outside of the laminate as a gas, it may push up the particle layer formed on the resin substrate, causing the shape to become distorted. For this reason, it is preferable to reduce the thickness of the resin substrate to reduce the influence on the particle layer.

[0169] Specifically, the thickness (μm) of the resin substrate is preferably 10 times or less, more preferably 5 times or less, and even more preferably 2 times or less, of the thickness of the particle layer on the resin substrate. Here, the thickness of the particle layer is defined as the thickness of the resin substrate surface as (x, y) and the thickness of the layer in the direction of lamination of the resin substrate as ( z), it indicates the difference between the maximum and minimum values ​​of z in the region (x, y, z) where each particle arranged on the resin substrate exists.

[0170] The thickness of the particle layer on the resin substrate is calculated by observing the cross section of the laminate 15 with a BIB-SEM, determining the particle presence area (x, z) using image processing software, where x is the resin substrate surface and z is the lamination direction of the resin substrate, and then calculating the difference between the maximum and minimum values ​​of z. Here, the BIB-SEM imaging conditions, required image area, and image processing method are the same as those described below.

[0171] The thickness of the resin substrate may be determined using a BIB-SEM, as with the particle size of the active material particles, or may be measured using a digital thickness gauge, etc. In addition, in SEM observation using a BIB-SEM, methods for identifying the active material particles, solid electrolyte particles, substrate, and adhesive portion include elemental composition analysis using EDS.

[0172] The cross-sectional observation of the electrode is obtained from the two-dimensional image obtained by a scanning electron microscope of the cross-section processed by a broad ion beam (BIB) with Ar. Hereinafter, the observation method of the aforementioned two-dimensional image is called BIB-SEM. The details of the measurement method will be described later.

[0173] <Imaging method of BIB-SEM> The cross-section of the electrode is imaged by BIB-SEM. The imaging conditions of BIB-SEM are described below. When the electrode is included in the battery, the battery is disassembled and a sample containing the electrode is taken out. For example, in the case of a laminated battery, the lamination is opened and a laminate containing the electrode is taken out. In order to suppress the load of the following cross-section processing, the other current collector and electrode unnecessary for imaging are separated from the laminate, and a sample containing the electrode is taken out. The electrode can be specified as the region between the electrolyte layer and the current collector layer. The sample is cut with a wire saw (DWS3400 / wire diameter 170 μm · diamond diameter 30 μm) so as to be a cut surface along the stacking direction. The cross-section is processed by a broad ion beam with Ar (JEOL SM-09010 Cross Section Polisher) on the cut surface. The conditions for cross-section processing are a voltage of 6 kV and a current of 150 - 200 mA. As a BIB-SEM image, a cross-section in the stacking direction of the electrode sample is obtained and cross-sectional observation is performed. Instead of the broad ion beam (BIB), a fine ion beam (FIB) with changed ion particle intensity and beam diameter in the beam can also be used.

[0174] The cross-section is imaged by an electron microscope (ULTRA55) under the following conditions. Detector: ESB (reflected electron image) Observation conditions: acceleration voltage 3 kV Magnification: 1000 times Filter: Apply a bias of 1500 V to the ESB filter

[0175] Next, elemental and compositional analysis of each particle of the electrode and the conductive resin was performed using SEM-EDX (Bruker XFlash Detector 630M) to distinguish between the active material particles, electrolyte particles, and the conductive resin. The active material particles, electrolyte particles, and conductive resin are identified using the method described above. The electrode is analyzed using X-ray diffraction (XRD) or the like to identify the materials that make up the electrode. Then, the specific elements contained in the active material particles, electrolyte particles, and conductive resin are detected and identified using SEM-EDX using the method described above. In addition to the X-ray diffraction described above, the materials that make up the electrode can also be identified using electron energy loss spectroscopy (EELS) in a TEM. They can also be identified using Raman spectroscopy or TOF-SIMS, and the materials that make up the electrode may be identified by combining the above analytical methods.

[0176] The thickness of the resin substrate is preferably 1 μm or more and 1 mm or less, and the thickness of the particle layer is preferably 0.1 μm or more and 100 μm or less.

[0177] Using a substrate made of an organic material such as resin as the substrate makes it easier to remove the substrate by heating. Materials that can be used to form the substrate include polyesters such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), and polyamides such as nylon. Of these, PET is preferred from the viewpoints of its decomposition temperature and the low toxicity of gases generated during thermal decomposition.

[0178] The sintering apparatus preferably exhausts the released gas to the outside of the heating furnace 42 using the pressure reducing means 423b. The resin base material can be burned and removed by creating an oxidizing atmosphere, i.e., an atmosphere containing oxygen gas such as air, inside the heating furnace 42 using the atmospheric gas supply means 423a or the like. However, depending on the active material particles and electrolyte particles used, sintering in an oxidizing atmosphere may cause decomposition or composition changes. In such cases, sintering in an inert atmosphere (Ar, N, etc.) or a reducing atmosphere (Ar-H) is preferred.

[0179] As described above, when the resin substrate is gasified by pyrolysis and released as gas from the laminate 15, the particle layers in the laminate 15 may be pushed up and change shape. Therefore, when heating in the heating furnace 42, the laminate 15 may be pressurized by the pressurizing means 422 before or during heating.

[0180] FIG. 13A is a BIB-SEM image of the cross section of the laminate after the second step. It corresponds to the cross section of laminate 15, in which six lamination units, each including particle layer 12 and second substrate 11b, are stacked on resin substrate 14 so that particle layers 12 and second substrate 11b alternate. FIG. 13B is a BIB-SEM image of three-dimensional object 16 after the third step. The resin substrate has been removed from laminate 15, resulting in three-dimensional object 16 consisting of six particle layers. FIG. 13C is an SEM image of the top of three-dimensional object 16. The first particles P1 and second particles P2 periodically arranged on second substrate 11b in the first step remain after the second step.

[0181] Fig. 14A is a BIB-SEM image of a three-dimensional object 16 according to one embodiment (Example 1) of the present disclosure, and Fig. 14B is an enlarged image of Fig. 14A. A three-dimensional object 16 is formed by the manufacturing method of the present disclosure using positive electrode active material particles LiCoO2 (hereinafter referred to as LCO) as the first particles P1 and electrolyte particles Li3BO3 (hereinafter referred to as LBO) as the second particles P2. In this embodiment, as shown in FIGS. 14A and 14B, the LCO particles (first particles P1) have a core portion P1a, a shell portion P1b, and radially protruding protrusions P1c on the surface of the shell portion. A gap portion P1d exists between the core portion and the shell portion. In FIG. 14B, P1d is an internal hole within the active material particle that communicates with the outer surface of the active material particle, and can also be referred to as a communicating hole 19-1. The LCO particles also have an inner surface 19 as indicated by a solid line.

[0182] The presumed mechanism by which the three-dimensional object 16 has the above-described configuration in this embodiment will be described with reference to FIGS. 15 to 18-1 and 18-2A to 18-2D. FIG. 15A shows an example of a temperature profile for each step (S101 to S104) of the manufacturing method of an electrode precursor according to the present disclosure, as well as a profile showing the redox behavior depending on the atmosphere. FIG. 15B is a schematic diagram showing the changes in the LCO particles in the profile shown in FIG. 15A. In the first step (S101) and the second step (S102), the LCO particles on the resin substrate remain unchanged because they are produced at room temperature in an air atmosphere (or an inert atmosphere). In contrast, in the third step (S103), the resin substrate is heated in a sintering treatment device (air atmosphere). When the temperature exceeds the melting point of the resin substrate and the substrate is sufficiently heated, the weight of the substrate begins to decrease.

[0183] Figure 16 shows the results of thermogravimetry (TG) of the resin substrate. Weight loss begins at around 300°C, which exceeds the melting point of the resin substrate (approximately 260°C). Figure 17 shows the results of thermogravimetry-mass spectrometry (TG-MS). Figure 17A shows the measurement results for a mixed sample of LCO particles and a resin substrate. Figure 17B shows the measurement results for a sample consisting of only the resin substrate. Around 300°C, when the weight of the resin substrate begins to decrease, an increase in molecules with a molecular weight of 28, believed to be carbon monoxide (CO), a reducing gas, is observed. In Figure 17B, CO tends to increase up to around 500°C (solid line in Figure 17B), whereas in Figure 17A, CO tends to decrease just before 400°C (solid line in Figure 17A). Furthermore, around 500°C in Figure 17A, a decrease in molecules with a molecular weight of 32, believed to be oxygen, is observed (dashed line in Figure 17A), and an increase in molecules with a molecular weight of 44, believed to be carbon dioxide, is observed (dotted line in Figure 17A). The following can be inferred from the results of TG and TG-MS.

[0184] As the temperature rises, the weight of the resin substrate begins to decrease (around 300°C), and the reducing gas CO is generated, increasing the reducibility. Some of the generated CO contributes to the reduction of the LCO particles. As a result, the LCO particles are reduced and decomposed, and are thought to change into particles P1r, which have some voids inside the LCO particles (Figure 15B). On the other hand, the amount of CO generated decreases as the base material decreases, making it gradually more difficult for reductive decomposition to occur. As the base material weight continues to decrease, the influence of CO decreases, and oxidation becomes dominant over reduction for the LCO particles. The reduced particles P1r are oxidized again to LiCoO2, which is trivalent Co (around 500°C). At this point, it is thought that the LCO particles change into LCO particles with a core P1a, a shell P1b, and radially protruding protrusions P1c on the surface of the shell, while retaining the voids P1d generated during reductive decomposition inside the LCO particles. 18-2A to 18-2D show the STEM-EELS results (Figs. 18-2A to 18-2D) for the LCO particle (Fig. 18-1) after the third step at each of the regions shown in Figs. 18-2A to 18-2D. It can be seen that the core region P1a (Area 4 in Fig. 18-2D), shell region P1b (Area 2 in Fig. 18-2B), and protrusion region P1c (Area 1 in Fig. 18-2A) of the LCO particle contain Co and are oxides with roughly the same composition.

[0185] (4th step) The fourth step is a step of post-treating the three-dimensional object obtained in the third step. By performing the post-treatment, it becomes easier to fill the electrode precursor with the filler material in the filling step (step 2-1) described below. Examples of post-treatments include the pressurizing step described below, as well as physical and chemical treatments for improving wettability and packing properties, and known treatment methods can be used. Specifically, physical treatments include physical treatment of three-dimensional objects such as laser edging. Other examples include surface modification using UV irradiation or corona discharge, and chemical treatments such as gas adsorption. The pressurizing step will be described below as an example.

[0186] For example, the fourth step is a step of pressurizing the three-dimensional object 16 obtained in the third step from which the resin substrate has been removed (FIG. 12). The three-dimensional object 16 may be pressurized using a pressurizing means 422 during cooling or heat dissipation after heating. Alternatively, after the resin substrate has been removed using a sintering treatment device, the three-dimensional object 16 may be pressurized using a separate pressurizing device. The pressurizing method is not particularly limited, but is preferably performed using, for example, vacuum degassing, isostatic pressing, a general hydraulic press, or a roller press. Of these, a combination of vacuum degassing and isostatic pressing is preferred. It is also preferable to perform the fourth step by laminating the three-dimensional object with a release material such as nichrome foil, and more preferably by packaging it in a laminate film. The pressure applied during pressurization is preferably 5 to 500 MPa. By applying pressure, the size of the pores (voids) in the three-dimensional object from which the resin substrate has been removed decreases. This is generally known as the capillary phenomenon. As shown in the figure, as the pore size decreases, the liquid becomes more easily permeable. Therefore, by performing post-treatment under pressure, the filling property of the filler material during the filling process of the filler material described below is further improved. Furthermore, by performing post-treatment under pressure, the particles constituting the three-dimensional object can be more easily brought into contact with each other. As a result, the ionic conductivity and electronic conductivity can be increased, and the strength of the three-dimensional object can be increased. After the fourth step, another heat treatment may be performed to increase the density and strength of the three-dimensional object. In this case, the sintering treatment device of the third step may be used, or sintering may be performed using a separate device such as an electric furnace, a tubular furnace, a hot press, or a hot isostatic pressing (HIP) device.

[0187] The electrode precursor obtained through steps 1 to 4 contains active material particles and electrolyte particles and has voids. The voids refer to, for example, the gaps between the active material particles and the electrolyte particles. The presence of voids allows filling with a filler material, as described below. The proportion of voids in the electrode precursor may be 1 to 30% by volume, or may be 5 to 20% by volume. If the voids are small, it is difficult for the filler material to be filled into the electrode precursor during the filling process described below, making it difficult for the filler material to exert its effects. On the other hand, if the voids are large, contact between the active material particles and the electrolyte particles is insufficient, which can reduce the ionic and electronic conductivity within the electrode. The void ratio can be determined using a so-called 3D-SEM, in which continuous cross-sectional images are obtained by repeatedly performing cross-sectional processing (FIB) and SEM observation, and then reconstructed using analysis software to obtain a three-dimensional image. For a 50 μm x 50 μm area of ​​the electrode, cross-sectional processing and SEM observation are repeated every 0.1 μm in the stacking direction to obtain a 50 μm x 50 μm x 10 μm three-dimensional image, and the void ratio can be calculated. Alternatively, the void ratio can be determined from a two-dimensional BIB-SEM image of the positive electrode cross section. Alternatively, an SEM image of a 500 μm x 10 μm area including the center of the positive electrode cross section can be obtained to calculate the void ratio. It can be calculated as the ratio of voids (pixels) to the entire image (pixels) using commercially available image analysis software (Photoshop (registered trademark)).

[0188] <Electrode manufacturing method> An example of a method for manufacturing an electrode will be described in detail below with reference to the drawings. Hereinafter, the electrode can be made into a positive electrode by using a positive electrode precursor as the electrode precursor. Also, the electrode can be made into a negative electrode by using a negative electrode precursor as the electrode precursor.

[0189] The method for producing an electrode according to the present disclosure includes the following four steps (step 1-1, step 2-1, step 3-1, and step 4-1). It may also include step 5-1. The order of steps 1-1 and 2-1 is not particularly limited, and step 2-1 may be performed after step 1-1, or step 1-1 may be performed after step 2-1. FIG. 19 is an image diagram showing a method for manufacturing an electrode. (1) Step 1-1 (not shown) of preparing an electrode precursor containing active material particles and having voids between the active material particles. (2) Step 2-1 (S201 in FIG. 19) of preparing a filler material to be filled into the electrode precursor; (3) Step 3-1 (S202 in FIG. 19) of filling the filler material from the outside to the inside of the electrode precursor; (4) Step 4-1 (S203 in FIG. 19) of retaining the filler material filled in the electrode precursor inside the electrode precursor (5) Step 5-1 (S204 in FIG. 19) of post-treating the electrode precursor obtained in Step 4-1

[0190] (Step 1-1) Step 1-1 is a step of preparing an electrode precursor that contains active material particles and has voids between the active material particles. Step 1-1 is not particularly limited as long as it can prepare an electrode precursor, but the electrode precursor can be prepared using, for example, the above-mentioned method for producing an electrode precursor. That is, step 1-1 preferably includes a first step of forming a particle layer containing active material particles and electrolyte particles on a resin substrate having an adhesive portion, a second step of forming a laminate by stacking a plurality of resin substrates on which the particle layer has been formed, a third step of removing the resin substrate from the laminate to form a three-dimensional object containing the active material particles and the electrolyte particles, and a fourth step of post-treating the three-dimensional object.

[0191] (Step 2-1) Step 2-1 is a step of preparing a filler material to be filled into the electrode precursor. Step 2-1 includes blending and preparing the following raw materials. As described above, the filler material needs to be liquid in order to fill the voids in the electrode precursor. As the filler material, for example, a solution in which at least one selected from the group consisting of a conductive resin and a precursor of a conductive resin is dissolved in a solvent may be used, or a dispersion in which at least one selected from the group consisting of a conductive resin and a precursor of a conductive resin is dispersed in a dispersion medium may be used. As the precursor of the conductive resin, for example, a monomer, oligomer, or polymer of a thermosetting resin or a photocurable resin can be used. That is, the conductive resin is preferably a cured product of a precursor of the conductive resin. Specific examples of the precursor of the conductive resin include ionic compounds having a structure corresponding to the structures represented by the above formulas (1) to (6), the above polyols, and the above isocyanate compounds.

[0192] The filler material may be, for example, a mixture of the following raw materials: At least one selected from the group consisting of a conductive resin and a precursor of a conductive resin Supporting electrolyte such as lithium salt as needed Solvent or dispersion medium Conductive additives as needed

[0193] The solvent or dispersion medium is not particularly limited, and for example, an organic solvent can be used. Examples of the organic solvent include alcohols such as methanol and ethanol, ketones such as methyl ethyl ketone, acetone, and acetylacetone, and hydrocarbon solvents such as hexane and cyclohexane. Among these, methyl ethyl ketone is preferred.

[0194] The filler material may contain a supporting electrolyte. By containing the supporting electrolyte in the filler material, the conductive resin in the electrode can contain the supporting electrolyte. In addition, the above-mentioned supporting electrolyte and conductive assistant can be used.

[0195] (Step 3-1) Step 3-1 is a step of filling the electrode precursor from the outside to the inside with the filler material prepared in Step 2-1. The filling method can be a known liquid filling method. The filling method preferably includes, for example, a coating step of applying the filler material to the electrode precursor and a penetration step of penetrating the applied filler material into the inside of the electrode precursor. It is more preferable to include a penetration step of penetrating the filler material into the inside of the electrode precursor so that the filler material contacts the inner surfaces of the active material particles, or a penetration step of penetrating the filler material into the inside of the electrode precursor so that the filler material contacts the outer surfaces of the active material particles. Examples of devices used in the coating step include an inkjet device, a dispenser device, a dip coater, a spin coater, a spray coater, and a roll coater. Of these, a dispenser device is preferred. Examples of devices used in the penetration step include a vacuum dryer and a vacuum packaging machine. Pressure may be applied using a weight or the like to support penetration.

[0196] 20A is a schematic diagram showing the filling process using a dispenser device 511. Filling material 50 is contained in a syringe in dispenser device 511, and is applied to electrode precursor 18 through a nozzle at the tip of the syringe. Meanwhile, electrode precursor 18 formed on substrate 14 (electrode current collector or solid electrolyte sheet) is fixed to a support table 512. Here, the filler material may be applied to a surface 18-1 (hereinafter also referred to as a particle arrangement surface) opposite to a contact surface 18-2 (hereinafter also referred to as a substrate support surface) of the electrode precursor 18 that contacts the substrate 14, or to an end portion 17 of the electrode precursor 18, but is preferably applied to the end portion 17. The reason for this will be explained later. The end portions refer to the xz and yz surfaces when the substrate surface of the electrode precursor is the xy plane and the stacking direction is the z direction ( FIG. 13B ). In the third step, the electrode precursor 18 is formed into a three-dimensional object by removing the resin substrate from the laminate, and therefore the electrode precursor 18 has pores that communicate from the particle arrangement surface 18-1. In addition, pores that communicate from the end portion 17 are provided. This makes it easier for the filler material 50 to permeate evenly throughout the electrode precursor 18. As a result, the conductive resin is more likely to be positioned so as to contact the inner surfaces of the active material particles. In addition, the conductive resin is more likely to be positioned so as to contact the outer surfaces of the active material particles and connect the active material particles. Furthermore, at the end portions, the interlayer spaces of the laminated structure of the electrode precursor are exposed, so when the filler material is applied to the end portions, the filler material is easily filled into the interior. On the other hand, when the filler material 50 is applied from the particle arrangement surface 18-1 of the electrode precursor 18, that is, from the xy plane, it is preferable to apply small amounts at multiple locations on the xy plane in order to ensure uniform penetration.

[0197] 20B is a schematic diagram showing the filling process using a dip coating device 513. Filling material 50 is contained in a dipping container 514. As dip coating device 513 moves in the direction of the arrow, filling material 50 is applied to the end of electrode precursor 18.

[0198] 20C is a schematic diagram showing the filling process using a spin coater 515. The filling material 50 is contained in a syringe in a dispenser device 511 and is applied onto the resin substrate 14 through a nozzle at the tip of the syringe. Meanwhile, the electrode precursor 18 formed on the resin substrate 14 (electrode current collector or solid electrolyte sheet) is fixed to a support table of the spin coater 515. The filling material 50 applied onto the resin substrate 14 is applied to the end of the electrode precursor 18 by the centrifugal force of the spin coater 515.

[0199] (Step 4-1) Step 4-1 is a step of retaining the filler material filled in the electrode precursor in step 3-1 inside the electrode precursor. The means for retaining the filler material is not particularly limited and is appropriately selected depending on the filler material. Examples include a step of thickening the filler material and a step of hardening the filler material. Specifically, when a thermosetting polymer electrolyte is used as the filler material, known means such as a vacuum oven can be used. When a UV-curable polymer electrolyte is used as the filler material, known means such as a UV irradiation device can be used. When using a UV irradiation device, depending on the thickness of the electrode, the filling material may not be cured easily by UV irradiation. In that case, the thickness of the electrode precursor is set to a thickness that allows the filled filling material to be easily cured, and multiple electrode precursors are molded on a substrate with high releasability, and after the filling material has been cured in each electrode precursor, they are transfer-laminated to obtain an electrode. Furthermore, the filling in step 3-1 may be carried out all at once, or may be carried out in small amounts in multiple separate steps. Specifically, when the filling is carried out in small amounts in multiple separate steps, the electrode may be obtained as follows. That is, after a small amount of filling in step 3-1 is carried out once, the filling material is held inside the electrode precursor in step 4-1. Thereafter, the filling in step 3-1 is carried out again, and the filling material is held inside the electrode precursor in step 4-1. In this way, the electrode precursor may be obtained by repeatedly carrying out steps 3-1 and 4-1. The electrode precursor obtained in step 4-1 can be used as an electrode. The electrode precursor obtained in the step 4-1 is preferably subjected to the step 5-1 to form an electrode.

[0200] (Step 5-1) Step 5-1 is a step of post-treating the electrode precursor obtained in Step 4-1 to obtain an electrode. Examples of post-treatment include a pressurizing step of pressurizing the electrode precursor obtained in Step 4-1, a buffer layer formation step of forming an interfacial buffer layer with the electrolyte on the surface of the electrode, and a packaging step of covering with a protective film or vacuum-packaging with an aluminum laminate film to prevent peeling, cracking, and exposure to the atmosphere during transportation and storage. The pressurizing means used in the pressurizing step can be known means, and specific examples include vacuum degassing, isostatic pressing, a general hydraulic press, and a roller press. Among these, it is preferable to use a combination of vacuum degassing and isostatic pressing. The buffer layer formation process can be performed using known coating methods, such as vacuum deposition, ion plating, sputtering, chemical vapor deposition (CVD), and the various coating methods described in step 3-1. Instead of using the above methods, a separately prepared buffer layer sheet (e.g., a polymer electrolyte sheet) can be laminated. Alternatively, a buffer layer can be formed on the electrode by controlling the amount of filler material in step 3-1 in advance so that the filler material used in step 3-1 also serves as a buffer layer.

[0201] <Secondary battery manufacturing method> A secondary battery can be manufactured using the above-described method for manufacturing an electrode. The method for manufacturing a secondary battery is not particularly limited, but the following specific examples can be given. The following describes the case where the above-mentioned electrode manufacturing method is used as a manufacturing method for a positive electrode or a negative electrode. A positive electrode, a negative electrode, or both a positive electrode and a negative electrode can be manufactured by the above-mentioned electrode manufacturing method using a current collector or an electrolyte formed by a separate means as a base.

[0202] The secondary battery can be manufactured by laminating electrodes, current collectors, and electrolytes, optionally packaging the laminate with an aluminum laminate film or the like, and then molding and pressurizing the laminate. That is, the manufacturing method of the secondary battery may include the step of laminating electrodes, current collectors, and electrolytes. The electrodes can be any of the above-described electrodes. Furthermore, a method for manufacturing a secondary battery may include the steps of preparing an electrode by the above-described electrode manufacturing method and providing a solid electrolyte adjacent to the electrode. Alternatively, the method may include the steps of simultaneously providing the above-described electrode and the solid electrolyte adjacent to the electrode. That is, the electrode and the solid electrolyte may be prepared separately in separate steps, or may be prepared together in the same step.

[0203] Here, the alternative means for forming the electrolyte is a known means, such as forming electrolyte particles into pellets using a uniaxial press or the like, and sintering the pellets in an electric furnace or the like. The manufactured components are stacked in the order of a positive electrode current collector, a positive electrode, an electrolyte, a negative electrode, and a negative electrode current collector to manufacture a secondary battery. Examples of secondary batteries include laminated batteries packed in a laminate film and coin batteries packed in a coin case. The particles constituting the positive electrode, electrolyte, and negative electrode may differ in the appropriate temperature and atmosphere during sintering. When handling such materials, it is preferable to separately manufacture the positive electrode, electrolyte, and negative electrode components and assemble them into a battery. Furthermore, when lithium metal or indium is used as the negative electrode, it is preferable to use the negative electrode as a metal foil or to form it into a current collector or electrolyte by a vacuum process such as sputtering. Because lithium metal has a strong reducing power, it is easily decomposed depending on the type of solid electrolyte. In this case, a buffer layer may be provided between the electrode and the electrolyte. It is preferable to use a polymer electrolyte or the like as the buffer layer.

[0204] In a specific example of the method for producing the secondary battery, the electrode is produced by forming a laminate of a positive electrode or a negative electrode on a current collector or an electrolyte as a base using the above-mentioned method for producing an electrode. On the other hand, a laminate including two or more selected from the group consisting of a positive electrode current collector, a positive electrode, an electrolyte, a negative electrode, and a negative electrode current collector, which are the main components of a secondary battery, can be formed and manufactured as a three-dimensional object including an electrode. For example, each substrate is prepared using the particle arrangement device 1. That is, a positive electrode current collector substrate, a positive electrode substrate, an electrolyte substrate, a negative electrode substrate, and a negative electrode current collector substrate. Each substrate may contain multiple types of particles (for example, positive electrode active material particles and electrolyte particles in the case of a positive electrode substrate), or may contain only a single type of particle. When only a single type of particle is contained, a single type of dense particle layer can be formed on the substrate by using the same type of filler in the filling devices 24a and 24b. The electrolyte base material is formed of a particle layer containing electrolyte particles. The negative electrode base material is formed of a particle layer containing negative electrode active material particles. The current collector base material is formed of a particle layer containing conductive particles. These base materials are stacked in the order of positive electrode current collector base material, positive electrode base material, electrolyte base material, negative electrode base material, and negative electrode current collector base material using a laminate molding device to produce a laminate, and a three-dimensional object containing an electrode is formed using a sintering treatment device to obtain a secondary battery precursor containing an electrode precursor. A filling material is filled and retained in the electrode precursor (steps 2-1 to 4-1), allowing the secondary battery to be manufactured. Furthermore, a bipolar secondary battery can be manufactured in the same manner, in which a positive electrode and a negative electrode are laminated on both sides of a current collector substrate. In this case, the filler material is filled and held in at least the electrodes, but it may also be filled and held in the electrolyte or current collector other than the electrodes.

[0205] <Electrode complex> The electrode composite includes the electrode of the present disclosure and an electrolyte layer that transfers active material between the electrode and the electrode. By further providing an electrode that serves as a positive electrode or a negative electrode in the electrode composite, it is possible to provide a secondary battery that can mitigate expansion and contraction of the active material particles and suppress a decrease in battery output.

[0206] <Secondary battery> The secondary battery includes a positive electrode according to the present disclosure and an electrolyte layer that transfers active material between the positive electrode and the electrolyte layer. The secondary battery also includes a negative electrode that transfers active material between the negative electrode and the electrolyte layer. This secondary battery can mitigate expansion and contraction of active material particles and suppress a decrease in battery output. Furthermore, by using a solid electrolyte such as an ion-conductive solid as the electrolyte layer, the secondary battery can be an all-solid-state battery. The method for manufacturing the secondary battery is not particularly limited, but the above-mentioned manufacturing method can be used. [Example]

[0207] The present disclosure will be described in more detail below using examples, but the present disclosure is not limited to these examples. In the following examples, unless otherwise specified, the number of parts is based on parts by mass.

[0208] Example 1 [Example of positive electrode manufacturing] <Example of manufacturing a positive electrode precursor> The positive electrode precursor according to Example 1 was formed by the above-described method for producing an electrode precursor. First, using a particle arrangement device 1 shown in FIG. 2, a particle layer consisting of positive electrode active material particles (first particles P1) and electrolyte particles (second particles P2) was formed on a resin substrate having an adhesive portion to form a resin substrate (first step). The first particles P1 were LiCoO2 (hereinafter referred to as LCO), and the second particles P2 were Li3BO3 (hereinafter referred to as LBO). The LCO used was manufactured by Nippon Chemical Industry Co., Ltd. (Cellseed C-5H), and the LBO used was manufactured by Toshima Manufacturing Co., Ltd. The first substrate 11a was a PDMS (ultraviolet curable liquid silicone rubber) sheet having a concave-convex structure on its surface. The second substrate 11b was a polyester (PET) sheet. A resin sheet was used, with adhesive portions coated with an acrylic adhesive material on both sides. The thickness of the second substrate 11b (PET) used was 3 μm. The thickness of the adhesive portion was 1 μm. LCO particles were arranged in a honeycomb pattern on the resin sheet, and LBO particles were arranged in the areas where no LCO particles were arranged (FIG. 9B).

[0209] The resin substrate with the particle layer formed thereon obtained in the first step was used in the second step. That is, the resin substrate with the particle layer formed thereon was laminated (three layers) on a current collector AC-1 (Al foil) using the laminate molding apparatus U3 shown in Fig. 11 to form a laminate. Thereafter, the resin substrate was removed from the laminate by heating using a sintering treatment device U4 shown in Fig. 12 to form a three-dimensional object (third step). The sintering atmosphere was air, the sintering temperature was 510°C, and the sintering time was 1 hour. The three-dimensional object was laminated with a release agent (nichrome foil), packed in a laminate film (Co-pack), and vacuum-packed using a vacuum packaging machine. The vacuum-packed laminate film was pressurized (196 MPa) using an isostatic pressure device for 1 minute to obtain a positive electrode precursor (fourth step).

[0210] <Example of filling material preparation (Step 2-1)> (Production Example of Ionic Compound I-01) A stirring bar and tetrahydrofuran (THF The flask was cooled in an ice bath. A solution of 10.2 g (0.15 mol) of imidazole (Tokyo Chemical Industry Co., Ltd.) dissolved in 60 mL of THF was slowly added dropwise, and the ice bath was removed. The mixture was stirred at room temperature for 2 hours. 47.6 g (0.38 mol) of 2-bromoethanol (Tokyo Chemical Industry Co., Ltd.) was added at room temperature, and the mixture was heated to reflux at 70°C for 7 hours. The reaction mixture was filtered, and the insoluble matter was washed away with THF. The solvent in the filtrate was evaporated under reduced pressure. The resulting product was dissolved in 200 mL of dichloromethane, and an aqueous solution of 43.6 g (0.15 mol) of lithium bis(trifluoromethanesulfonyl)imide (Tokyo Chemical Industry Co., Ltd.) was added as an anion source. The mixture was stirred at room temperature for 10 hours. The resulting solution was separated to obtain an organic layer. This organic layer was washed three times with pure water. Next, dichloromethane was distilled off under reduced pressure to obtain ionic compound I-01. Ionic compound I-01 is a compound represented by the following formula: [ka]

[0211] (Example of manufacturing a precursor of a conductive resin) Under a nitrogen atmosphere, 19.6 parts by mass of polymeric MDI (trade name: Millionate MR-200, manufactured by Tosoh Corporation) as an isocyanate was slowly added dropwise to 120.5 parts by mass of polyether polyol (trade name: Adeka Polyol PR-5007, manufactured by ADEKA Corporation) in a reaction vessel while maintaining the temperature inside the reaction vessel at 65°C. After completion of the addition, the mixture was allowed to react at a temperature of 65°C for 3.5 hours. The resulting reaction mixture was cooled to room temperature, and 49.8 parts by mass of methyl ethyl ketone was added to obtain a solution of an isocyanate-terminated prepolymer with an isocyanate group content of 2.5% by mass.

[0212] The following materials were mixed with 100 parts by mass of the obtained solution of isocyanate group-terminated prepolymer and stirred to obtain a filling material. Adeka Polyol PR-5007 113 parts by mass Ionic compound I-1 3.7 parts by mass Supporting electrolyte (lithium bis(trifluoromethanesulfonyl)imide (Tokyo Chemical Industry Co., Ltd.)) 18.6 parts by mass Methyl ethyl ketone 175 parts by mass

[0213] Next, the positive electrode precursor obtained in the fourth step was filled with the prepared filling material from a part of the end face located on the periphery of the positive electrode precursor using the application device shown in FIG. 20A (step 3-1). The positive electrode precursor filled with the filler material was heated in a vacuum oven (140°C) for 1 hour to harden the filler material into a conductive resin, and positive electrode A-1 was formed (step 4-1). Samples with varying filling amounts of the filler material were prepared, and the BIB-SEM described above was used to determine the level at which the conductive resin had penetrated into the electrode without excess or deficiency.

[0214] A secondary battery was fabricated using the formed positive electrode A-1. The fabrication method will be explained. The electrolyte layer SE-1 and the negative electrode C-1 other than the positive electrode A-1 were prepared by the following method. The electrolyte layer SE-1 was made of Li 1.5 Al 0.5 Ge 1.5 P3O 12The electrolyte sheet (thickness: 260 μm) was prepared by pelletizing LAGP (hereinafter referred to as LAGP) powder (manufactured by Toshima Manufacturing Co., Ltd.) using a uniaxial press and sintering it in an electric furnace (850 °C / 12 h). The negative electrode C-1 was made of indium foil (thickness: 50 μm, manufactured by Nilaco). The positive electrode current collector AC-1 (Al foil thickness 20 μm), positive electrode A-1, electrolyte layer SE-1, negative electrode C-1, and negative electrode current collector CC-1 (Cu foil thickness 20 μm) were stacked in this order, and the tab lead for the extraction electrode, which had been previously welded to the current collector, was packaged in an aluminum laminate film so that it was positioned outside the laminate. The laminate was then formed into a laminate cell shape using a vacuum packaging machine and pressurized (196 MPa) for 1 minute using an isostatic pressure pressurizer to produce secondary battery SB-1.

[0215] 22A to 22D are electron microscope images of the cross section of the positive electrode A-1 taken using a method described below. FIG. 22A is an electron microscope image. FIG. 22B identifies LCO particles (P1t, P1u, P1v, P1w, P1x, P1y, and P1z) based on an EDX image (element Co), with particle boundaries indicated by dashed lines. The LCO particles have a core portion P1a, a shell portion P1b, and protrusions P1c that protrude radially from the surface of the shell portion. Furthermore, gaps P1d exist between the core portion and the shell portion (FIG. 14). In FIG. 22B, the boundaries of the gaps P1d within the particles P1t and P1u are indicated by solid lines. In other words, the solid lines can be said to represent the inner surfaces of the active material particles. Figure 22C is an EDX image of sulfur element derived from the conductive resin. As in Figure 22B, particle boundaries are indicated by dashed lines. The conductive resin is present so as to contact the inner surfaces of the gaps P1d, i.e., the inner surfaces of the active material particles. The conductive resin is also arranged so as to contact the outer surfaces of the LCO particles and connect the LCO particles. Figure 22D is an EDX image of boron element derived from the solid electrolyte LBO. As in Figure 22B, particle boundaries are indicated by dashed lines. As can be seen from Figures 22C and 22D, conductive resin and inorganic electrolyte are unevenly distributed between the LCO particles.

[0216] FIG. 23 is a low-magnification electron microscope image of the cross section of positive electrode A-1. FIG. 23A is an electron microscope image. FIG. 23B identifies LCO particles based on an EDX image (element Co), with particle boundaries indicated by dashed lines. FIG. 23C is an EDX image (element Co), FIG. 23D is an EDX image (element C), and FIG. 23E is an EDX image (element B). In FIGS. 23C to 23E, the boundaries of LCO particles are indicated by dashed lines. A conductive resin is present so as to contact the inner surface of the gap portion P1d, i.e., the inner surface of the active material particle. Furthermore, the conductive resin is arranged so as to contact the outer surface of the LCO particles and connect the LCO particles. Furthermore, the conductive resin is It exists so as to overlap with the area containing BO.

[0217] 24A to 24C are schematic diagrams illustrating features of the present disclosure, for example, according to Example 1. Fig. 24A is a schematic diagram of an electrode, Fig. 24B shows the element distribution of EDX along line A-A' in Fig. 24A, and Fig. 24C shows the element distribution of EDX along line B-B' in Fig. 24A. 24A to 24C, the conductive resin is disposed in contact with the outer surfaces of the active material particles and connects the active material particles together, forming a good interface with the active material particles as well as with the supporting electrolyte particles, which is thought to improve ion diffusion within the electrode. It is also believed that the conductive resin changes shape in response to the expansion and contraction of the active material particles during charging and discharging, thereby suppressing the decline in ionic and electronic conductivity. Furthermore, it is believed that the voids within the electrode function as spaces for deformation, including expansion and contraction of the conductive resin in response to the expansion and contraction of the active material particles.

[0218] The conductive resin also fills the gaps P1d within the LCO particles. That is, it is positioned so as to contact the inner surfaces of the LCO particles. In this way, the conductive resin forms a good interface with the LCO particle surfaces having the protrusions P1c, and also with the gaps P1d within the LCO particles, which is thought to further improve ion diffusion within the electrode. Furthermore, by filling the LCO particles with flexible conductive resin, the shape changes in response to the expansion and contraction of the active material particles during charge and discharge. This is thought to prevent a decrease in ionic conductivity and electronic conductivity within the particles. Furthermore, the conductive resin in contact with the inner and outer surfaces of the active material particles deforms in response to the expansion and contraction of the active material particles during charge and discharge, so as to bridge discontinuities within the active material particles (e.g., cracks and gaps) and discontinuities between particles (e.g., voids), thereby maintaining ionic conductivity.

[0219] <Cross-section observation of positive electrode> To observe the cross section of the positive electrode, the battery was disassembled in the stacking direction and the positive electrode was removed. The removed positive electrode was cut with a wire saw (DWS3400 / wire diameter 170 μm, diamond diameter 30 μm). The cut surface was cross-sectioned using a broad ion beam of Ar (JEOL SM-09010 Cross Section Polisher). The cross-section processing conditions were a voltage of 6 kV and a current of 150 to 200 mA. The cross section was photographed using an electron microscope (ULTRA55) to obtain a BIB-SEM image under the following conditions. Detector: ESB (backscattered electron beam) Observation conditions: accelerating voltage 3 kV Magnification: 1000x Filter: ESB filter biased to 1500V

[0220] Next, elemental mapping was performed using SEM-EDX (XFlash Detector 630M manufactured by Bruker Corp.) From the elemental mapping results, the active material particles, electrolyte particles, and conductive resin were identified.

[0221] The evaluation method for the secondary battery will be described below. <Charge / discharge characteristics capacity retention rate> The mass of active material particles per unit area of ​​the resin substrate on which the particle layer is formed, M (g / cm 2 ) to calculate the mass of the positive electrode active material particles (M × number of layers × positive electrode area cm 2 The mass M of the active material particles per unit area was calculated as follows. The weight of the first substrate 11a was measured after the first particles P1 were filled by the first filling device 24a in the particle placement device 1. Next, the first particles P1 were transferred to the second substrate 11b. After the heating, the weight of the first substrate 11a was measured. The difference between the weights was calculated to determine the mass of the first particles P1 on the second substrate 11b. The mass of the first particles P1 was then divided by the area of ​​the second substrate 11b (the area of ​​the concave-convex region) to calculate the mass M of the active material particles per unit area.

[0222] Another calculation method is to use ICP emission spectroscopy. The active material particle mass per unit area M (g / cm) can be calculated in advance using the method described above. 2 Three levels of resin substrates with particle layers formed on them, where the Co concentration is clearly determined, are prepared. These resin substrates are dissolved by microwave acid decomposition (ETHOS PRO), and the acid decomposition solution is diluted with ultrapure water. Then, ICP-AES measurement (CIROS CCD) is performed to quantify the Co element. The active material particle mass per unit area M (g / cm) relative to the obtained element concentration is calculated. 2 From the calibration curve, the active material particle mass M (g / cm) per unit area of ​​the resin substrate on which the particle layer to be measured is formed can be calculated. 2 ) can be obtained.

[0223] The current value at a current rate of 0.4 C was determined, and charge / discharge measurements (constant current charge / constant current discharge) were performed at a current rate of 0.4 C. The measurements were performed using a charge / discharge device (manufactured by Biologic). Figure 21 shows the measured charge / discharge curves. The vertical axis represents the battery cell voltage (V vs. Li / Li + The horizontal axis represents the capacity of the battery cell (mAh / g), and the horizontal axis represents the capacity per mass of the positive electrode active material. The actual capacity of the LCO was 120 mAh / g, and the cutoff voltage (vs. Li) was 4.2 V (charge) / 2.6 V (discharge). The capacity retention rate was the ratio of the discharge capacity to the charge capacity (discharge capacity / charge capacity × 100%). The above measurement was repeated five times, and the average value was calculated. A value of 80% or more was considered good.

[0224] <Cycle characteristics> A cycle evaluation (repeated charge / discharge measurement in constant current mode) was performed at a current rate of 0.4 C. The above capacity retention rate was measured by repeating charge / discharge measurements until the capacity retention rate reached 80% or less, and the number of times n was calculated. A value of 10 or more was considered good. As a result of the battery evaluation, the capacity retention rate was 100% and the number of cycles n was 12. If the charge / discharge characteristics and cycle characteristics were good according to the above evaluation, the battery was rated as A (Table 1).

[0225] Example 2 A positive electrode A-2 was produced in the same manner as in Example 1, except that the filler material was applied to the particle arrangement surface of the positive electrode precursor and filled into the positive electrode precursor. A secondary battery SB-2 was produced in the same manner as in Example 1, except that the positive electrode A-2 was used. When a cross-section of positive electrode A-2 was observed, it was found that, similar to positive electrode A-1, the conductive resin was located in contact with the inner surface of the gap. Also, similar to positive electrode A-1, the conductive resin was located in contact with the outer surface of the LCO particles, connecting the LCO particles. Furthermore, similar to positive electrode A-1, the conductive resin overlapped the region containing LBO. Furthermore, the conductive resin and the inorganic electrolyte were unevenly distributed between the LCO particles. Furthermore, it was confirmed that the obtained secondary battery SB-2 had good capacity retention and cycle characteristics, similar to the secondary battery SB-1.

[0226] Example 3 A positive electrode A-3 was produced in the same manner as in Example 1, except that the sintering temperature in the third step was changed from 510° C. to 700° C. A secondary battery SB-3 was produced in the same manner as in Example 1, except that the positive electrode A-3 was used. 25A to 25C are electron microscope images of a cross section of the positive electrode A-3. FIG. 25A is an electron microscope image, FIG. 25B is an EDX image (element C), and FIG. 25C is an EDX image (element B). Perhaps due to the firing, oxidation of the LCO particles progressed, returning them to a form similar to that of the raw LCO particles, and no gaps were observed. In the cross-sectional structure of the obtained cathode A-3, the conductive resin was in contact with the outer surfaces of the LCO particles and arranged to connect the LCO particles. Furthermore, as in cathode A-1, the conductive resin was present so as to overlap the region containing LBO. Furthermore, the conductive resin and the inorganic electrolyte were unevenly distributed between the LCO particles. Furthermore, it was confirmed that the obtained secondary battery SB-3 had good capacity retention and cycle characteristics, similar to the secondary battery SB-1.

[0227] Example 4 A positive electrode A-4 was produced in the same manner as in Example 1, except that the first particles were replaced with LCO particles (CellSeed C-8H) having a larger particle size. Cross-sectional observation of the positive electrode A-4 revealed that, similar to the positive electrode A-1, the conductive resin was located so as to contact the inner surface of the gap. Similarly to the positive electrode A-1, the conductive resin was located so as to contact the outer surface of the LCO particles and connect the LCO particles. Similarly to the positive electrode A-1, the conductive resin overlapped the region containing LBO. Furthermore, the conductive resin and the inorganic electrolyte were unevenly distributed between the LCO particles. Furthermore, similar to the secondary battery SB-1, the resulting secondary battery SB-4 was confirmed to have good capacity retention and cycle characteristics.

[0228] Example 5 A positive electrode A-5 was produced in the same manner as in Example 1, except that pressure (50 MPa) was applied using the pressure means 422 in the sintering apparatus U4. Cross-sectional observation of the positive electrode A-5 revealed that, similar to the positive electrode A-1, the conductive resin was located in contact with the inner surface of the gaps. Similarly to the positive electrode A-1, the conductive resin was located in contact with the outer surface of the LCO particles, connecting the LCO particles. Similarly to the positive electrode A-1, the conductive resin overlapped the region containing LBO. Furthermore, the conductive resin and the inorganic electrolyte were unevenly distributed between the LCO particles. Furthermore, similar to the secondary battery SB-1, the resulting secondary battery SB-5 was confirmed to have good capacity retention and cycle characteristics.

[0229] Example 6 Li as electrolyte particles 5.9 Yb 0.81 La 0.09 Zr 0.1 A positive electrode A-6 was produced in the same manner as in Example 1, except that (BO3)3(LYbBO-1) was used. A secondary battery SB-6 was produced in the same manner as in Example 1, except that the positive electrode A-6 was used. When a cross-section of positive electrode A-6 was observed, it was found that, similar to positive electrode A-1, the conductive resin was located in contact with the inner surface of the gap. Also, similar to positive electrode A-1, the conductive resin was located in contact with the outer surface of the LCO particles, connecting the LCO particles. Furthermore, similar to positive electrode A-1, the conductive resin overlapped the region containing LBO. Furthermore, the conductive resin and the inorganic electrolyte were unevenly distributed between the LCO particles. Furthermore, it was confirmed that the obtained secondary battery SB-6 had good capacity retention and cycle characteristics, similar to the secondary battery SB-1.

[0230] Table 1 shows a comparison table summarizing the formulations and production conditions of Examples 1 to 6 and the evaluation results. [Table 1] In the table, the application location indicates the location where the filler material was applied to the positive electrode precursor in step 3-1, the contact location indicates the contact location between the conductive resin and the LCO particles, and the presence or absence of co-localization indicates whether the conductive resin and the inorganic electrolyte are co-localized.

[0231] The present disclosure relates to the following configurations and methods. [Configuration 1] An electrode applied to a secondary battery, the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; The conductive resin is positioned so as to contact the inner surface. [Configuration 2] The electrode according to Aspect 1, wherein the conductive resin includes an ionic conductive resin. [Aspect 3] 3. The electrode according to claim 1, wherein the conductive resin comprises a resin containing an ionic functional group and a supporting electrolyte. [Configuration 4] 4. The electrode according to any one of configurations 1 to 3, wherein the conductive resin contains a urethane resin containing an ionic functional group and a supporting electrolyte. [Configuration 5] 5. The electrode according to any one of configurations 1 to 4, wherein the inner surface is continuous with the outer surface of the active material particles. [Configuration 6] 6. The electrode according to claim 5, wherein the conductive resin is in contact with the outer surface. [Configuration 7] 7. The electrode according to any one of configurations 1 to 6, wherein at least one selected from the group consisting of a conductive resin, a conductive assistant, and a supporting electrolyte is present between the active material particles. [Configuration 8] A supporting electrolyte is contained between the active material particles, 8. The electrode according to any one of aspects 1 to 7, wherein the supporting electrolyte comprises an inorganic electrolyte. [Configuration 9] 9. The electrode of claim 8, wherein, between the particles, a region containing the conductive resin overlaps a region containing the inorganic electrolyte. [Configuration 10] 10. The electrode according to any one of aspects 1 to 9, wherein the active material particles contain lithium cobalt oxide. [Configuration 11] 11. The electrode according to any one of embodiments 5 to 10, wherein the active material particles have protrusions protruding from the outer surface. [Configuration 12] 12. The electrode according to any one of configurations 1 to 11, wherein the conductive resin contains at least one of polyurethane, polyacrylic, and polyether in the main chain structure. [Configuration 13] The electrode according to any one of Aspects 1 to 12, wherein the conductive resin contains, in its main chain structure, a polyether that is a copolymer of polyethylene glycol and polypropylene glycol. [Aspect 14] 14. The electrode according to any one of configurations 1 to 13, wherein the conductive resin has higher flexibility than the active material particles. [Configuration 15] An electrode applied to a secondary battery, the electrode includes active material particles and a conductive resin, the active material particles have an outer surface; The resin is disposed in contact with the outer surface and connects the active material particles. [Configuration 16] 16. The electrode of claim 15, wherein the conductive resin includes an ionic conductive resin. [Configuration 17] 17. The electrode according to aspect 15 or 16, wherein the conductive resin contains at least one of polyurethane, polyacrylic, and polyether in its main chain structure. [Configuration 18] 18. The electrode according to any one of aspects 15 to 17, wherein the conductive resin contains polyether, which is a copolymer of polyethylene glycol and polypropylene glycol, in its main chain structure. [Configuration 19] the active material particles have an inner surface; 19. The electrode according to any one of aspects 15 to 18, wherein the inner surface is continuous with the outer surface. [Configuration 20] 20. The electrode of claim 19, wherein the conductive resin is positioned so as to contact the inner surface. [Configuration 21] A supporting electrolyte is contained between the active material particles, 21. The electrode according to any one of aspects 15 to 20, wherein the supporting electrolyte comprises an inorganic electrolyte. [Configuration 22] 22. The electrode of claim 21, wherein, between the particles, a region containing the conductive resin overlaps a region containing the inorganic electrolyte. [Configuration 23] An electrode composite including an electrode and an electrolyte layer that transfers an active material between the electrode and the electrolyte layer, 23. An electrode composite, wherein the electrode is the electrode according to any one of aspects 1 to 22. [Configuration 24] A secondary battery including a positive electrode and an electrolyte layer that transfers an active material between the positive electrode and the electrolyte layer, The positive electrode is the electrode according to any one of configurations 1 to 22, The secondary battery includes a negative electrode that transfers the active material between the negative electrode and the electrolyte layer. [Method 25] A 1-1 step of preparing an electrode precursor including active material particles and having gaps between the active material particles; a 2-1 step of preparing a filling material to be filled into the electrode precursor; a 3-1 step of filling the filling material from the outside to the inside of the electrode precursor; and a 4-1 step of retaining the filler material filled inside the electrode precursor inside the electrode precursor. [Method 26] 26. The method for producing an electrode according to Method 25, wherein Step 3-1 includes a penetration step of penetrating the filler material into the interior of the electrode precursor so as to be in contact with the outer surfaces of the active material particles. [Method 27] 27. The method for producing an electrode according to Method 25 or 26, wherein Step 1-1 includes a step of forming an inner surface on the active material particles. [Method 28] 28. The method for producing an electrode according to Method 27, wherein the step of forming an inner surface on the active material particles is a step of sintering the active material particles. [Method 29] The step 1-1 is a first step of forming a particle layer containing active material particles and electrolyte particles on a resin substrate having an adhesive portion; a second step of forming a laminate by laminating a plurality of resin substrates on which the particle layer is formed; a third step of removing the resin substrate from the laminate to form a three-dimensional object containing active material particles and electrolyte particles; A fourth step of post-treating the three-dimensional object; 29. A method for producing an electrode according to any one of methods 25 to 28, comprising: [Method 30] 30. The method for producing an electrode according to any one of Methods 25 to 29, wherein Step 3-1 includes a penetration step of penetrating the filler material into the interior of the electrode precursor so as to contact the inner surfaces of the active material particles. [Method 31] the electrode precursor has an end portion; 31. The method for producing an electrode according to any one of Methods 25 to 30, wherein Step 3-1 includes a step of applying the filling material to the end portion of the electrode precursor.

Claims

1. An electrode applied to a secondary battery, the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; the conductive resin is positioned so as to be in contact with the inner surface, The conductive resin is an electrode containing a resin having an ionic functional group and a supporting electrolyte.

2. An electrode for use in a secondary battery, comprising: the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; the conductive resin is positioned so as to be in contact with the inner surface, The conductive resin is an electrode containing a urethane resin containing an ionic functional group and a supporting electrolyte.

3. An electrode for use in a secondary battery, comprising: the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; the conductive resin is positioned so as to be in contact with the inner surface, The electrode contains a supporting electrolyte between the active material particles, the supporting electrolyte containing an inorganic electrolyte.

4. An electrode for use in a secondary battery, comprising: the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; the conductive resin is positioned so as to be in contact with the inner surface, the inner surface is continuous with the outer surface of the active material particle, The active material particles have protrusions protruding from the outer surface of the electrode.

5. The electrode according to claim 4 , wherein the conductive resin includes an ionic conductive resin.

6. 5. The electrode according to claim 4, wherein the conductive resin comprises a resin containing an ionic functional group and a supporting electrolyte.

7. 5. The electrode according to claim 4, wherein the conductive resin contains a urethane resin containing an ionic functional group and a supporting electrolyte.

8. The electrode according to claim 1 , wherein the inner surface is continuous with the outer surface of the active material particle.

9. The electrode according to claim 8 , wherein the conductive resin is in contact with the outer surface.

10. The electrode according to claim 1 , wherein at least one selected from the group consisting of a conductive resin, a conductive assistant, and a supporting electrolyte is contained between the active material particles.

11. A supporting electrolyte is contained between the active material particles, 10. The electrode of claim 1, wherein the supporting electrolyte comprises an inorganic electrolyte.

12. The electrode according to claim 3 , wherein, between the particles, a region containing the conductive resin overlaps a region containing the inorganic electrolyte.

13. 10. The electrode of claim 1, wherein the active material particles comprise lithium cobalt oxide.

14. The electrode according to claim 8 , wherein the active material particles have protrusions protruding from the outer surface.

15. 2. The electrode according to claim 1, wherein the conductive resin contains at least one of polyurethane, polyacrylic, and polyether in its main chain structure.

16. 2. The electrode according to claim 1, wherein the conductive resin contains, in its main chain structure, a polyether, which is a copolymer of polyethylene glycol and polypropylene glycol.

17. The electrode according to claim 1 , wherein the conductive resin has a higher flexibility than the active material particles.

18. An electrode composite including an electrode and an electrolyte layer that transfers an active material between the electrode and the electrolyte layer, the electrode includes active material particles and a conductive resin, the active material particles have an inner surface; The conductive resin is positioned so as to be in contact with the inner surface.

19. An electrode composite including an electrode and an electrolyte layer that transfers an active material between the electrode and the electrolyte layer, An electrode composite, wherein the electrode is the electrode according to any one of claims 1 to 17.

20. A secondary battery including a positive electrode and an electrolyte layer that transfers an active material between the positive electrode and the electrolyte layer, The positive electrode is the electrode according to any one of claims 1 to 17, The secondary battery includes a negative electrode that transfers the active material between the negative electrode and the electrolyte layer.

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