Method for manufacturing a component of an all-solid-state sodium ion secondary battery

Abstract

To provide a method for manufacturing a member for a power storage device, which has high production efficiency and low cost, and can easily form a large-area current collector layer.SOLUTION: There is provided a method for manufacturing a power storage device member 10 including a step of forming a current collector layer 2 by a wet film-forming method.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a member for an electricity storage device. [Background technology]

[0002] In recent years, with the widespread use of portable personal computers and mobile phones, the development of energy storage devices such as lithium-ion secondary batteries and sodium-ion secondary batteries has progressed rapidly. Current energy storage devices primarily use organic electrolytes. While organic electrolytes exhibit high ionic conductivity, they are liquids and flammable, raising concerns about potential risks such as leakage and fire when used in energy storage devices. Therefore, development is also underway to replace organic electrolytes with solid electrolytes and develop all-solid-state batteries with solid cathodes and anodes.

[0003] Generally, a current collector layer made of metal foil or the like is provided on the surface of an electrode layer in an electricity storage device, and serves as a terminal for extracting electrons. Here, if the adhesion between the electrode layer and the metal foil is poor and sufficient conductivity cannot be imparted to the electrode, a gas phase method such as sputtering or vapor deposition may be used (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-97034 [Patent Document 2] WO2018 / 225494 publication Summary of the Invention [Problem to be solved by the invention]

[0005] The vapor-phase deposition method requires a vacuum process and a low deposition rate, which means it takes a long time to deposit the current collector layer. This results in low production efficiency and high manufacturing costs. Another problem with the vapor-phase deposition method is that it is difficult to deposit a large-area current collector layer because the size of the deposition device (chamber) is limited.

[0006] In view of the above, an object of the present invention is to provide a method for producing a member for an electricity storage device, which has high production efficiency and low cost, and which also makes it possible to easily form a current collector layer with a large area. [Means for solving the problem]

[0007] The method for manufacturing an electricity storage device member of the present invention is characterized by comprising a step of forming a current collector layer by a wet film-forming method. The wet film-forming method allows the current collector layer to be formed in a shorter time than conventional vapor-phase methods, thereby improving the production efficiency of electricity storage device members. Furthermore, compared to vapor-phase methods, the wet film-forming method is less restricted by the size of the film-forming apparatus, making it easy to form large-area current collector layers.

[0008] In the method for producing a power storage device member of the present invention, the wet film formation method is preferably a spray coating method, a screen printing method, a dispenser method, a slit die coating method, an inkjet method, a casting method, or a spin coating method.

[0009] In the method for producing an electricity storage device member of the present invention, the wet film-forming method is preferably a spray coating method. Among wet film-forming methods, the spray coating method is easy to simplify the equipment, and therefore makes it easy to enjoy the effects of the present invention.

[0010] In the method for producing an electricity storage device member of the present invention, it is preferable that the current collector layer contains at least one metal selected from Al, Ti, Fe, Ni, Cu, Mo, Ag, and Au, or at least one carbon material selected from acetylene black, carbon black, carbon nanotubes, and graphene.

[0011] In the method for producing an electricity storage device member of the present invention, the current collector layer is preferably formed on the surface of the electrode layer.

[0012] In the method for producing a power storage device member of the present invention, the current collector layer preferably has a thickness of 0.1 to 1000 μm.

[0013] In the method for producing a member for an electricity storage device of the present invention, the area of ​​the current collector is 0.1 cm 2 It is preferable that this is equal to or greater than this.

[0014] In the method for producing an electricity storage device member of the present invention, the electricity storage device is preferably a sodium ion secondary battery, and more preferably an all-solid-state sodium secondary battery.

[0015] The method for producing an electricity storage device of the present invention is characterized by comprising a step of producing a member for an electricity storage device by any of the above methods. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a method for producing a member for an electricity storage device, which has high production efficiency and low cost, and also makes it possible to easily form a current collector layer with a large area. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic cross-sectional view showing one embodiment of an electricity storage device member produced by the method of the present invention. [Figure 2] 1 is a schematic cross-sectional view showing one embodiment of an electricity storage device produced by a method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments will be described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. In addition, in the drawings, components having substantially the same functions may be referred to by the same reference numerals.

[0019] Fig. 1 is a schematic cross-sectional view showing one embodiment of an electricity storage device member produced by the method of the present invention. As shown in Fig. 1, an electricity storage device member 10 includes a positive electrode layer 1 and a current collector layer 2. The current collector layer 2 is formed on one main surface of the positive electrode layer 1. The electricity storage device member 10 may also include a negative electrode layer instead of the positive electrode layer 1.

[0020] FIG. 2 is a schematic cross-sectional view showing one embodiment of an electricity storage device manufactured by the method of the present invention. The electricity storage device of this embodiment is an all-solid-state battery. As shown in FIG. 2, an electricity storage device 20 includes a positive electrode layer 1, a negative electrode layer 3, a solid electrolyte layer 4, and a current collector layer 2. Here, the positive electrode layer 1 is formed on one main surface of the solid electrolyte layer 4, and the negative electrode layer 3 is formed on the other main surface. Furthermore, a current collector layer 2 is formed on the main surface of the positive electrode layer 1 opposite the solid electrolyte layer 4, and a current collector layer 2 is formed on the main surface of the negative electrode layer 3 opposite the solid electrolyte layer 4. The current collector layers 2 formed on each surface of the positive electrode layer 1 and the negative electrode layer 3 may be made of the same material or different materials. Note that in this embodiment, the current collector layer 2 is formed on both the main surfaces of the positive electrode layer 1 and the negative electrode layer 3, but the current collector layer 2 may be formed on only one of the main surfaces of the positive electrode layer 1 and the negative electrode layer 3.

[0021] The present invention is characterized in that the current collector layer 2 is formed by a wet film-forming method. The wet film-forming method allows the current collector layer to be formed in a shorter time than conventional vapor-phase methods, thereby improving the production efficiency of members for electricity storage devices. Furthermore, compared to vapor-phase methods, there are fewer restrictions imposed by the size of the film-forming apparatus, making it possible to easily form large-area current collector layers. Examples of wet film-forming methods include spray coating, screen printing, dispenser methods, slit-die coating, inkjet methods, casting, and spin coating. Among these, spray coating is particularly effective in simplifying the equipment required, making it easier to achieve the above-mentioned effects.

[0022] The current collector layer 2 preferably contains at least one metal selected from Al, Ti, Fe, Ni, Cu, Mo, Ag, and Au, or at least one carbon material selected from acetylene black, carbon black, carbon nanotubes, and graphene. It is more preferable that the current collector layer 2 be made of at least one metal selected from Al, Fe, Ni, Cu, Ag, and Au, which have excellent electrical conductivity. Al, which has excellent electrical conductivity and is lightweight, is most preferable. The current collector layer 2 may be made of a single material, or may be made of a composite material or alloy of two or more materials.

[0023] The thickness of the current collector layer 2 is preferably 0.1 to 1000 μm, 0.1 to 500 μm, and particularly preferably 0.1 to 100 μm. If the current collector layer is too thin, the resistance will be high, whereas if it is too thick, the energy density per unit volume and energy density per unit weight of the electricity storage device member 10 and the electricity storage device 20 will tend to decrease.

[0024] The area of ​​the current collector layer 2 is not particularly limited, but the larger the area, the easier it is to enjoy the effects of the present invention. Specifically, the area of ​​the current collector layer 2 is 0.1 cm 2 More than 1cm 2 More than 10cm 2 Above, especially 100cm 2 Although there is no particular upper limit to the area of ​​the current collector layer 2, if it is too large, it becomes difficult to uniformly control the thickness. 2 It is preferable that:

[0025] The paint used to form the current collector layer 2 preferably contains an organic component. When the paint contains an organic component, the metal components (metal particles) that make up the current collector layer 2 can be more easily dispersed in the paint, which in turn makes it easier to obtain a current collector layer 2 with a uniform thickness. Specific examples of organic components include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; esters such as ethyl acetate and butyl acetate; alcohols such as n-butanol, isopropyl alcohol, ethanol, diacetone alcohol, and isobutanol; ethers such as dimethyl ether and ethylene glycol monobutylene ether; amides such as N,N-dimethylformamide; N-methylpyrrolidone; and acrylic resins.

[0026] After forming the current collector layer 2 by a wet film-forming method using the above-mentioned coating material, post-treatments such as heating and washing may be carried out to remove organic components, if necessary. The heat treatment is preferably carried out at a temperature close to the decomposition temperature of the organic components. However, such post-treatments are not necessarily required.

[0027] The components other than the current collector layer 2 will be described below.

[0028] (Positive electrode layer 1) The positive electrode layer 1 can be produced, for example, by sintering a positive electrode active material precursor powder. The positive electrode active material precursor powder is preferably made of an amorphous oxide material that generates positive electrode active material crystals upon firing. The amorphous oxide material generates positive electrode active material crystals during firing, and also softens and flows, making it possible to form a denser positive electrode layer 1. This is preferable because it results in good formation of ion conduction paths. In addition, in the present invention, the "amorphous oxide material" is not limited to a completely amorphous oxide material, but also includes those that contain some crystals (for example, a crystallinity of 10% or less).

[0029] The positive electrode active material precursor powder preferably contains, in mole percent oxide equivalents, 25% to 55% Na2O, 10% to 30% Fe2O3 + Cr2O3 + MnO + CoO + NiO, and 25% to 55% PO5. The reasons for limiting the composition in this way are explained below. In the following explanation of the content of each component, "%" means "mol percent" unless otherwise specified.

[0030] Na2O has the general formula Na x M y P2O z (M is at least one transition metal element selected from Fe, Cr, Mn, Co, and Ni, 1.20≦x≦2.10, 0.95≦y≦1.60) and is the main component of the positive electrode active material crystal. The Na2O content is preferably 25% to 55%, and more preferably 30% to 50%. If the Na2O content is too low or too high, the charge / discharge capacity tends to decrease.

[0031] Fe2O3, Cr2O3, MnO, CoO and NiO also have the general formula Na x M y P2O zIt is the main component of the positive electrode active material crystal represented by the formula: Fe2O3+Cr2O3+MnO+CoO+NiO. The content of Fe2O3+Cr2O3+MnO+CoO+NiO is preferably 10% to 30%, and more preferably 15% to 25%. If the content of Fe2O3+Cr2O3+MnO+CoO+NiO is too low, the charge / discharge capacity tends to decrease. On the other hand, if the content of Fe2O3+Cr2O3+MnO+CoO+NiO is too high, undesired crystals such as Fe2O3, Cr2O3, MnO, CoO, or NiO are likely to precipitate. In order to improve cycle characteristics, it is preferable to actively include Fe2O3. The content of Fe2O3 is preferably 1% to 30%, more preferably 5% to 30%, even more preferably 10% to 30%, and particularly preferably 15% to 25%. The content of each of Cr2O3, MnO, CoO and NiO is preferably 0% to 30%, more preferably 10% to 30%, and even more preferably 15% to 25%. When at least two components selected from Fe2O3, Cr2O3, MnO, CoO and NiO are contained, the total content is preferably 10% to 30%, and more preferably 15% to 25%.

[0032] In this specification, "x+y+..." means the total amount of each component. Here, each component does not necessarily need to be contained as an essential component, and some components may not be contained (i.e., the content is 0%).

[0033] P2O5 also has the general formula Na x M y P2O z It is the main component of the positive electrode active material crystal represented by the formula: The P2O5 content is preferably 25% to 55%, and more preferably 30% to 50%. If the P2O5 content is too low or too high, the charge / discharge capacity tends to decrease. In addition to the above components, the positive electrode active material precursor powder may contain V2O5, Nb2O5, MgO, Al2O3, TiO2, ZrO2, or Sc2O3. These components have the effect of increasing electrical conductivity (electronic conductivity), which tends to improve the high-speed charge / discharge characteristics of the positive electrode active material. The total content of the above components is preferably 0% to 25%, and more preferably 0.2% to 10%. If the content of the above components is too high, heterogeneous crystals that do not contribute to the battery characteristics are generated, which tends to reduce the charge / discharge capacity.

[0034] In addition to the above components, SiO2, B2O3, GeO2, Ga2O3, Sb2O3, or Bi2O3 may be contained. The inclusion of these components improves glass-forming ability, making it easier to obtain a homogeneous positive electrode active material precursor powder. The total content of the above components is preferably 0% to 25%, and more preferably 0.2% to 10%. Because the above components do not contribute to battery characteristics, if their content is too high, charge / discharge capacity tends to decrease.

[0035] The positive electrode active material precursor powder is preferably produced by melting and molding a raw material batch. This method is preferred because it makes it easier to obtain an amorphous positive electrode active material precursor powder with excellent homogeneity. Specifically, the positive electrode active material precursor powder can be produced as follows.

[0036] First, raw materials are prepared to obtain a raw material batch having the desired composition. Next, the obtained raw material batch is melted. The melting temperature may be adjusted appropriately so that the raw material batch is homogeneously melted. For example, the melting temperature is preferably 800°C or higher, and more preferably 900°C or higher. There is no particular upper limit, but a melting temperature that is too high can lead to energy loss and evaporation of sodium components, etc., so the upper limit is preferably 1500°C or lower, and more preferably 1400°C or lower.

[0037] The molten material is then molded by any method, and may be, for example, cast between a pair of cooling rolls and molded into a film while rapidly cooling, or may be poured into a mold and molded into an ingot.

[0038] The resulting compact is then pulverized to obtain a cathode active material precursor powder. The average particle size of the cathode active material precursor powder is preferably 0.01 μm or more and less than 50 μm, more preferably 0.03 μm or more and 10 μm or less, even more preferably 0.05 μm or more and 0.6 μm or less, and particularly preferably 0.1 μm or more and 0.5 μm or less. If the average particle size of the cathode active material precursor powder is too small, the particles will have strong cohesion when used in a paste, making it difficult to disperse in the paste. Furthermore, when mixed with a solid electrolyte powder or the like, it becomes difficult to uniformly disperse the cathode active material precursor powder in the mixture, which increases internal resistance and may result in reduced output characteristics and a reduced charge / discharge capacity. On the other hand, if the average particle size of the cathode active material precursor powder is too large, the diffusion distance of ions and electrons in the cathode material increases, increasing internal resistance and reducing output characteristics, resulting in a tendency for the charge / discharge capacity to decrease. Furthermore, when mixed with a solid electrolyte powder, the adhesion between the positive electrode active material precursor powder and the solid electrolyte powder decreases, which tends to reduce the mechanical strength of the positive electrode layer 1 and, as a result, reduce the charge / discharge capacity. Alternatively, the adhesion between the positive electrode layer 1 and the solid electrolyte layer 4 is also poor, which may cause the positive electrode layer 1 to peel off from the solid electrolyte layer 4.

[0039] In the present invention, the average particle size is D 50 (volume-based average particle size) and refers to the value measured by laser diffraction scattering method.

[0040] (Negative electrode layer 3) The negative electrode layer 3 contains a negative electrode active material capable of absorbing and releasing sodium ions during charge and discharge. Examples of the negative electrode active material include metallic materials such as metal Na, metal Sn, metal Bi, metal Zn, Sn-Cu alloys, and Bi-Cu alloys; carbon materials such as hard carbon; and oxide materials containing Ti and / or Nb as elements. Among these, carbon materials and oxide materials containing Ti and / or Nb as elements are preferred because they are highly safe and are abundant resources. In particular, materials with an oxidation-reduction potential of 1.5 V (vs. Na / Na) during charge and discharge are preferred. + It is preferable to use an oxide material containing a crystalline phase represented by Na4TiO(PO4)2, Na5Ti(PO4)3, or Na2Ti3O7, which has a molecular weight of 0.01 or less. In this case, the operating voltage of the negative electrode of the sodium ion secondary battery increases, and the precipitation of metallic Na dendrites during repeated charge and discharge can be suppressed.

[0041] (Solid electrolyte layer 4) Examples of the solid electrolyte layer 4 include beta-alumina or NASICON crystals, which have excellent sodium ion conductivity. Beta-alumina has two crystal types: β-alumina (theoretical composition: Na2O·11Al2O3) and β"-alumina (theoretical composition: Na2O·5.3Al2O3). β"-alumina is a metastable substance, so it is usually used with Li2O or MgO added as a stabilizer. β"-alumina has higher sodium ion conductivity than β-alumina, so it is preferable to use β"-alumina alone or a mixture of β"-alumina and β-alumina. Li2O-stabilized β"-alumina (Na 1.7 Li 0.3 Al 10.7 O 17 ) or MgO-stabilized β”-alumina ((Al 10.32 Mg 0.68 O 16 )(Na 1.68 It is more preferable to use O).

[0042] The solid electrolyte layer 4 can be produced by mixing raw material powders, molding the mixed raw material powders, and then firing the molded product. For example, the solid electrolyte layer 4 can be produced by forming a green sheet from the raw material powders into a slurry, and then firing the green sheet. Alternatively, the solid electrolyte layer 4 may be produced by a sol-gel method.

[0043] The thickness of the solid electrolyte layer 4 is preferably in the range of 5 μm to 1500 μm, and more preferably in the range of 10 μm to 200 μm. If the thickness of the solid electrolyte layer 4 is too thin, the mechanical strength decreases and the layer becomes more susceptible to breakage, which makes an internal short circuit more likely to occur. If the thickness of the solid electrolyte layer 4 is too thick, the sodium ion conduction distance during charge and discharge increases, which increases the internal resistance and makes it more likely that the discharge capacity and operating voltage will decrease. In addition, the energy density per unit volume and the energy density per unit weight of the all-solid-state sodium ion secondary battery will also tend to decrease.

[0044] (solid electrolyte powder) It is preferable that the positive electrode layer 1 and / or the negative electrode layer 3 contain a solid electrolyte powder. In this way, the solid electrolyte powder can enhance the ionic conductivity of the positive electrode layer 1 and the negative electrode layer 3. The solid electrolyte powder is preferably made of the same material as the solid electrolyte layer 4. The average particle size of the solid electrolyte powder is preferably 0.05 μm or more and 3 μm or less, more preferably 0.05 μm or more and less than 1.8 μm, even more preferably 0.05 μm or more and 1.5 μm or less, particularly preferably 0.1 μm or more and 1.2 μm or less, and most preferably 0.1 μm or more and 0.7 μm or less. If the average particle size of the solid electrolyte powder is too small, not only is it difficult to uniformly disperse the powder in the positive electrode layer 1 or the negative electrode layer 3, but moisture absorption and carbonation may cause a decrease in ionic conductivity or promote excessive reaction with the positive electrode active material or the negative electrode active material. As a result, the internal resistance of the positive electrode layer 1 or the negative electrode layer 3 tends to increase, resulting in reduced voltage characteristics and charge / discharge capacity. On the other hand, if the average particle size of the solid electrolyte powder is too large, the sinterability of the positive electrode layer 1 or the negative electrode layer 3 may be significantly impaired, resulting in a decrease in the smoothness of the resulting positive electrode layer 1 or the negative electrode layer 3 and an increase in internal resistance.

[0045] (Conductive additive) The conductive additive is a component that forms a conductive path in the positive electrode layer 1 or the negative electrode layer 3. For example, conductive carbon can be used as the conductive additive. As the conductive carbon, powdered or fibrous conductive carbon, such as highly conductive carbon black, such as acetylene black or ketjen black, is preferred. When conductive carbon is added to the positive electrode layer 1, it is preferably added when grinding the positive electrode active material precursor powder. The conductive carbon acts as a grinding aid, enabling homogeneous mixing with the positive electrode active material precursor powder, as well as suppressing excessive fusion between particles of the positive electrode active material precursor powder during firing, thereby ensuring electrical conductivity and improving rapid charge / discharge characteristics.

[0046] (binder) The binder is a material for integrating the raw materials (raw material powders) of the positive electrode layer 1 and the negative electrode layer 3. Examples of binders include water-soluble polymers such as cellulose derivatives such as carboxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl cellulose, ethyl cellulose, hydroxyethyl cellulose, and hydroxymethyl cellulose, and polyvinyl alcohol; thermosetting resins such as thermosetting polyimide, phenolic resin, epoxy resin, urea resin, melamine resin, unsaturated polyester resin, and polyurethane; polycarbonate resins such as polypropylene carbonate; and polyvinylidene fluoride.

[0047] The solid raw materials preferably contain, by mass, 30% to 100% active material powder (active material precursor powder), 0% to 70% solid electrolyte powder, and 0% to 20% conductive carbon; more preferably, 44.5% to 94.5% active material powder (active material precursor powder), 5% to 55% solid electrolyte powder, and 0.5% to 15% conductive carbon; and even more preferably, 50% to 92% active material powder (active material precursor powder), 7% to 50% solid electrolyte powder, and 1% to 10% conductive carbon. If the content of the active material powder (active material precursor powder) is too low, the amount of components that absorb or release sodium ions during charge and discharge tends to decrease, resulting in a decrease in the charge and discharge capacity of the energy storage device. If the content of the conductive carbon or solid electrolyte powder is too high, the binding strength of the active material powder decreases, increasing internal resistance, and therefore tending to decrease voltage characteristics and charge and discharge capacity.

[0048] The binder content is preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass, per 100 parts by mass of the solid raw materials. If the binder content is too low, the binding strength of the solid raw materials will be insufficient, which may cause cracks when the positive electrode layer 1 or the negative electrode layer 3 is dried or peeling from the solid electrolyte layer 4. If the binder content is too high, the binder will volatilize during firing, which may cause volume shrinkage of the positive electrode layer 1 or the negative electrode layer 3, making them more likely to crack or peel from the solid electrolyte layer 4.

[0049] In the above embodiment, the present invention has been mainly described as being applied to an all-solid-state sodium-ion secondary battery using a material having sodium ion conductivity, but it may also be applied to other all-solid-state batteries and all-solid-state battery components, such as an all-solid-state lithium-ion secondary battery using a material having lithium ion conductivity. Furthermore, it is not limited to the manufacture of all-solid-state batteries and all-solid-state battery components, and may also be applied to any electricity storage device and electricity storage device components. [Example]

[0050] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0051] Table 1 shows Examples 1 to 3 and Comparative Examples 1 and 2.

[0052] [Table 1]

[0053] (1) Preparation of the positive electrode layer The positive electrode active material precursor powder was 83%, the solid electrolyte powder was 13%, and the conductive additive was 4% by mass, and they were mixed using an agate mortar and pestle. The positive electrode active material precursor was a glass powder represented by the composition formula NaFeP0, and the solid electrolyte powder was LiO-stabilized β-alumina (manufactured by Ionotec, composition formula: Na 1.7 Li 0.3 Al 10.7 O 17 ) was ground into a powder, and acetylene black was used as the conductive additive. 20 parts by mass of polypropylene carbonate was added to 100 parts by mass of the resulting mixed powder, and then N-methylpyrrolidone was added so that the solid content concentration became 50% by volume. This was stirred using a planetary centrifugal mixer to form a slurry.

[0054] The obtained slurry was applied to the center of one surface of a 1 mm thick, 11.6 mm square solid electrolyte sheet by 1 cm. 2The solid electrolyte sheet was coated with the coating solution to a thickness of 100 μm on an area of ​​10 mm × 10 mm and dried at 70°C for 2 hours. The solid electrolyte sheet was then fired in an electric furnace at 500°C for 30 minutes in a mixed gas atmosphere of 24% by volume of H2 and 296% by volume of N2. This formed a positive electrode layer on one surface of the solid electrolyte sheet.

[0055] All of the above operations were carried out in an atmosphere with a dew point of −40° C. or lower.

[0056] (2) Deposition of the current collector layer (Examples 1 and 2) The surface of the positive electrode layer obtained above is sprayed with conductive paint to form a 1cm2 area. 2 A current collector layer measuring 10 mm x 10 mm and having a thickness of approximately 50 μm was formed. The time required for spray coating of the current collector layer was 10 seconds. The conductive paint used in Example 1 contained Ni particles and acrylic resin (PCS-104nNi, manufactured by Plascoat Co., Ltd.), while the conductive paint used in Example 2 contained Ag particles, Cu particles, and acrylic resin (PCS-107AgCu, manufactured by Plascoat Co., Ltd.).

[0057] Example 3 An Al current collector paste was prepared by adding 5 parts by weight of polypropylene carbonate as a binder to 100 parts by weight of Al particles (average particle diameter 2 μm), and then adding N-methylpyrrolidone to a solids concentration of 50% by volume. The Al current collector paste was printed on the resulting positive electrode layer by screen printing, forming an Al current collector layer on the positive electrode layer. The screen printing took 20 seconds.

[0058] (Comparative Examples 1 and 2) Using a sputtering apparatus (JEC-3000FC manufactured by JEOL Ltd.), a current collector layer made of Au or Al and having a thickness of 300 nm was formed on the surface of the obtained positive electrode layer in a vacuum atmosphere of less than 10 Pa. The time required to form the current collector layer was 7 minutes in Comparative Example 1 and 20 minutes in Comparative Example 2.

[0059] (3) Preparation of test battery In an argon atmosphere with a dew point of -60°C or less, metallic sodium was pressed onto the surface of the solid electrolyte sheet opposite the positive electrode layer to obtain a laminate. The resulting laminate was placed on the bottom cover of a coin cell, and then the top cover was placed on top to prepare a CR2032 test battery.

[0060] (4) Charge / discharge test The fabricated test battery was subjected to a charge-discharge test at 30° C. to measure the battery capacity. The theoretical capacity of the positive electrode was set to 96 mAh / g, and the C rate was set to 0.05 C. The results are shown in Table 1.

[0061] As shown in Table 1, in Examples 1 to 3, the current collector layer could be formed in a shorter time than in Comparative Examples 1 and 2. Furthermore, in Examples 1 to 3, the battery capacity was equivalent to that of Comparative Examples 1 and 2. [Explanation of symbols]

[0062] 1 Positive electrode layer 2. Current collector layer 3. Negative electrode layer 4 Solid electrolyte layer 10. Materials for energy storage devices 20 Energy storage devices

Claims

1. forming a current collector layer by a wet film forming method; the wet film-forming method is a spray coating method, 10. A method for manufacturing a member for an all-solid-state sodium ion secondary battery, wherein the current collector layer is formed by spraying a conductive paint onto the surface of the electrode layer.

2. 2. The method for producing a member for an all-solid-state sodium ion secondary battery according to claim 1, wherein the current collector layer contains at least one metal selected from Al, Ti, Fe, Ni, Cu, Mo, Ag, and Au, or at least one carbon material selected from acetylene black, carbon black, carbon nanotubes, and graphene.

3. 3. The method for producing a member for an all-solid-state sodium ion secondary battery according to claim 1, wherein the thickness of the current collector layer is 0.1 to 1000 μm.

4. The area of ​​the current collector is 0.1 cm ２ The method for producing a member for an all-solid-state sodium ion secondary battery according to any one of claims 1 to 3, characterized in that

5. A method for producing an all-solid-state sodium ion secondary battery, comprising the step of producing a member for an all-solid-state sodium ion secondary battery by the method according to any one of claims 1 to 4.

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