Method for producing material layer, and method for producing precursor of solid-state battery

Abstract

This method for producing a material layer comprises: a first step for forming a mask part on a portion of the surface of a first substrate; a second step for arranging first particles on the surface of the first substrate; a third step for removing the mask part from the first substrate; a fourth step for transferring the first particles to a second substrate; and a fifth step for arranging second particles on at least a portion of a region on the surface of the second substrate in which the first particles are not arranged.

Description

Method for manufacturing a material layer and a precursor for a solid-state battery

[0001] The present invention relates to a method for producing a material layer and a method for producing a precursor for a solid-state battery.

[0002] In recent years, various new manufacturing methods using additive manufacturing technologies have been developed. However, the technology of designing and arranging multiple material particles to create functional structures remains difficult and has not been widely realized. In particular, there are few technologies that design and arrange particles as they are. For example, the technology of arranging toner particles using electrophotography is widely used. However, the proportion of pigments that can function as functional materials in the toner is low, making it difficult to achieve functionality other than color. Electrostatic screen printing is a technology that can pattern particles without using a binder. However, the need to create a gap between the plate and the substrate makes it difficult to increase resolution. Furthermore, both technologies have difficulty creating thin films close to a single particle layer, and they also do not allow for high resolution in the stacking direction.

[0003] In contrast, Patent Document 1 discloses a method for manufacturing a material layer, which includes a first step of arranging first particles in a pattern on a substrate, and a second step of arranging second particles in areas on the substrate where the first particles are not arranged, and is characterized in that the second step includes a step of rubbing a support material carrying the second particles against the substrate on which the first particles are arranged.

[0004] Japanese Patent Application Laid-Open No. 2019-137060

[0005] However, with technological advances worldwide, there is a strong demand not only for improvements in absolute performance but also for manufacturing efficiency, i.e., stabilization of manufacturing quality and improvement in the yield rate. The present inventors reviewed the prior art in this regard and found the following problems. In the method for manufacturing a material layer disclosed in Patent Document 1, a particle pattern is created using an intaglio plate and then transferred to the adhesive surface of a substrate. However, when creating a pattern of particles 102 on the intaglio plate 101, if unwanted particles 102-1 also adhere to the convex portions, the particles may be deposited in unintended locations ( FIG. 1A ). Furthermore, during transfer to the second substrate 11, the particles 102-1 on the convex portions of the intaglio plate come into contact with the adhesive portion of the substrate, thereby suppressing the transfer load applied to the particles inside the intaglio plate ( FIG. 1B ). These problems could result in poor transfer. These problems need improvement.

[0006] The present disclosure provides a method for manufacturing a material layer that contributes to stabilizing manufacturing quality and improving the yield rate. The present disclosure also provides a method for manufacturing a precursor for a solid-state battery that contributes to stabilizing manufacturing quality and improving the yield rate.

[0007] The present disclosure provides a method for manufacturing a material layer, including: a first step of forming a mask portion on a portion of a surface of a first substrate; a second step of arranging first particles on the surface of the first substrate; a third step of removing the mask portion from the first substrate; a fourth step of transferring the first particles to a second substrate; and a fifth step of arranging second particles in at least a portion of an area of ​​the surface of the second substrate where the first particles are not arranged.

[0008] The present disclosure also provides a method for producing a precursor of a solid-state battery, including the method for producing the material layer of the present disclosure, wherein the second substrate is a resin substrate.

[0009] According to the present disclosure, a method for manufacturing a material layer that contributes to stabilizing manufacturing quality and improving the yield rate is provided. Also, according to the present disclosure, a method for manufacturing a precursor of a solid-state battery that contributes to stabilizing manufacturing quality and improving the yield rate is provided.

[0010] FIG. 1 is an explanatory diagram illustrating an embodiment of the present disclosure. FIG. 2 is an image diagram illustrating a method for manufacturing a material layer according to an aspect of the present disclosure. FIG. 3 is an explanatory diagram of a material layer manufacturing apparatus. FIG. 4 is an explanatory diagram of each step according to an aspect of the present disclosure. FIG. 5 is an explanatory diagram of each step according to an aspect of the present disclosure. FIG. 6 is an explanatory diagram of a laminate according to an aspect of the present disclosure.

[0011] 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 lower and upper limits, which are the endpoints, unless otherwise specified. Furthermore, when a numerical range is described in stages, the upper and lower limits of each numerical range can be arbitrarily combined. 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. Note that when XX is a group, multiple XXs may be selected, and the same applies to YY and ZZ.

[0012] The present disclosure relates to a method for manufacturing a material layer. The method for manufacturing a material layer includes a first step of forming a mask portion on a portion of a surface of a first substrate. The method also includes a second step of arranging first particles on the surface of the first substrate. The method further includes a third step of removing the mask portion from the first substrate. The method also includes a fourth step of transferring the first particles to a second substrate. The method also includes a fifth step of arranging second particles in at least a portion of the surface of the second substrate where the first particles are not arranged.

[0013] As a result of our investigations, we have found that the above-mentioned problem can be solved by incorporating the above-mentioned configuration into the manufacturing method of the material layer. Specifically, according to the above process, even if particles adhere to the mask portion 3-1, the adhered particles 102-1 can be removed together with the removal of the mask portion 3-1 (Figures 1C and 1D). This means that the amount of unwanted particles that may adhere to areas that are designed as non-image areas can be reduced. After the removal of the mask portion 3-1, the patterned first particles 22 remain only on the first substrate 1. Therefore, during transfer, the particle pattern directly contacts the adhesive layer, applying sufficient transfer pressure (Figure 4F), allowing for stable pattern formation. This is thought to be due to an improved particle transfer rate when transferring the first particles from the first substrate to the second substrate. Furthermore, if the intaglio projections are wide, the contact area with the adhesive portion of the substrate also increases, which can make peeling after transfer difficult. However, according to the above process, the mask portion is removed and the particle pattern only directly contacts the adhesive layer, making peeling after transfer easy.

[0014] FIG. 2 is a conceptual diagram illustrating a method for manufacturing a material layer according to one embodiment of the present disclosure. FIG. 4 is an explanatory diagram illustrating each step of the present disclosure. A mask layer 3 is attached to a first substrate 1 (FIGS. 4A and 4B). Then, openings 21 (areas where no mask portions are formed) are formed in the mask layer 3 (FIG. 4C). That is, a mask portion 3-1 is formed on a portion of the surface of the first substrate (Step 1). Then, first particles 22 are filled into the openings 21 (FIG. 4D). That is, the first particles are arranged on the surface of the first substrate (Step 2). Then, the mask portion is removed from the first substrate (Step 3, FIG. 4E). Finally, a second substrate 11 is pressed against the first particles 22 (FIG. 4F), and the first particles are transferred to the second substrate, transferring the particle pattern (Step 4, FIG. 4G). Additionally, second particles are arranged on at least a portion of the surface of the second substrate 11 where the first particles are not arranged (Step 5, FIG. 4H).

[0015] FIG. 3 illustrates an example of a material layer fabrication apparatus for implementing a material layer fabrication method according to one embodiment of the present disclosure. The material layer fabrication apparatus includes a transport device 2 for transporting a first substrate 1 between processes, a mask layer application unit consisting of a mask layer supply unit 30, a pressure roller 4, and a wet sponge roller 5, a mask fabrication unit (UV laser 6), a mask peeling unit consisting of a first particle supply unit 7, an air blower 8, a peeling roller 9, and a winding device 10, a particle pattern transfer unit consisting of a second substrate (not shown), a pressure roller 12, and a winding device 15, an air blower 14, and a second particle supply unit 13. The material layer fabrication method according to the present disclosure is implemented by sequentially performing processes in these units. While FIG. 3 illustrates a material layer fabrication apparatus configured to perform each process in a series, the present disclosure is not limited thereto and may include appropriate divisions between the processes.

[0016] An embodiment of the present disclosure will be described below, step by step, using the example of the material layer preparation apparatus shown in FIG. 3 . First, the first substrate is not particularly limited, but a support having a smooth surface is preferred. As a support having a smooth surface, as long as the surface to which the mask layer is attached is smooth, the other surface configurations can be optimized depending on the apparatus. The material of the first substrate may be the same as or different from that of the mask layer. From the perspective of improving patterning accuracy, it is preferable that the first substrate is resistant to deformation. In particular, deformation of the first substrate during mask removal can disrupt the formed first particle pattern, so high rigidity is desirable. If the rigidity of the first substrate is insufficient, a reinforcing member can be further provided on the back surface of the first substrate (the surface opposite to the side where the mask portion is formed). Furthermore, high abrasion resistance to the particle material used is preferable because it allows for repeated use. Wear of the first substrate not only reduces reusability but can also be included as impurities in the material layer.

[0017] The specific material of the first substrate is not particularly limited and may be selected depending on the particles used. Examples include resins such as polyimide resin, polyacetal resin, and polyester resin; metals such as aluminum, stainless steel, and invar alloy; and glass and ceramics. Glass is particularly preferred due to its high surface smoothness. The shape of the first substrate is also not particularly limited, as long as it is a shape that allows for at least line contact pressure. For example, it may be flat, or may be in the form of a roller or belt. Of these, a flat shape is preferred. In the material layer production apparatus of Figure 3, flat glass is used as the first substrate, and it is moved horizontally by a conveying device 2.

[0018] In the first step, a mask portion is formed on a portion of the surface of the first substrate 1. The means for forming the mask portion is not particularly limited and may include, for example, a step of providing a mask layer 3 on the first substrate and a step of forming openings 21 in the mask layer 3 to form a mask portion 3-1. The step of providing the mask layer 3 on the first substrate 1 is not particularly limited and may include, for example, a step of attaching the mask layer 3 to the first substrate 1. The means for attaching the mask layer 3 to the first substrate 1 is not particularly limited. In the material layer preparation apparatus of FIG. 3 , the mask layer 3 is attached by applying pressure using a pressure roller 4 having an elastic rubber surface. When attaching a smooth mask layer to the first substrate 1, if the mask layer is attached while removing the air layer, it can be attached using only the first substrate 1 and the mask layer 3 based on the principle of vacuum adhesion.

[0019] Furthermore, the first step preferably includes a step of increasing the fixing force between the mask layer 3 and the first substrate 1. Such a step is not particularly limited, and a wide range of known techniques can be applied. Examples include a step of forming a water film, a step of heating and pressurizing, a step of using external forces such as static electricity or magnetic force, and a step of providing an adhesive layer on the mask layer. Specifically, the steps are as follows: The material layer preparation apparatus of FIG. 3 has a wet sponge roller 5 for forming a thin water film on the surface of the first substrate 1 prior to attaching the mask layer 3. By providing a liquid layer such as a thin water film between the mask layer 3 and the first substrate 1, the effect of water film adsorption can be achieved. In other words, the first step more preferably includes a step of forming a water film on the surface of the first substrate.

[0020] When the mask is a resin film, the first step preferably includes a step of heating and pressurizing the mask layer. By attaching the mask layer by heating and pressurizing, the flexibility of the mask layer can be increased, and the adhesive strength with the first substrate can be increased. When the mask layer is made of a magnetic material, magnetic force or the like can also be used. Furthermore, in the step of providing the mask layer 3 on the first substrate 1, multiple mask layers may be provided in a stacked manner. In this case, one type of material for the mask layer may be used alone, or two or more types may be used in combination.

[0021] The thickness of the mask layer 3 is not particularly limited, but can be, for example, 1 to 100 μm or 2 to 50 μm. Furthermore, it is desirable that the thickness of the mask layer 3 be approximately uniform. The thickness of the mask layer 3 determines the depth of the openings 21, and the openings 21 determine the thickness of the particle layer. Therefore, it is desirable to select the thickness of the mask layer 3 according to the design of the particle layer thickness. For example, by using a mask layer with a thickness equivalent to the desired particle diameter, a particle pattern with a nearly single-layer particle layer can be formed. That is, the thickness of the mask layer is preferably approximately equal to the volume average particle diameter of the first particles. For example, the thickness of the mask layer (μm) is preferably 0.7 to 1.3 times the volume average particle diameter (μm) of the first particles. From the perspective of application and removal, a flexible mask layer is easier to handle. Furthermore, a mask layer with good drilling processability is desirable from the perspective of making the openings finer and improving planar resolution. For the reasons described above, the thickness of the mask portion is not particularly limited, but can be, for example, 1 to 100 μm or 2 to 50 μm. It is also desirable that the thickness of the mask portion is approximately uniform.

[0022] The specific material for the mask layer is not particularly limited, but it is desirable to select it depending on the particles used and the means for forming the openings used. If the mask layer is to be used repeatedly, metal foils such as aluminum, stainless steel, and invar are preferred. If the mask layer is to be disposable, resin films such as polyimide, polyacetal, and polyester are preferred. Polyester resins are particularly suitable, as they have good thermal processability and are easy to thin. Furthermore, if the mask layer is to be held in place by magnetic force, a magnetic material is preferred, and a ferromagnetic material is preferable. Therefore, metal foil is preferred. The specific material for the mask portion is also not particularly limited, and the above materials can be used for the same reasons as for the mask layer. The material layer preparation apparatus in Figure 3 uses a polyester resin film wound in roll form. Alternatively, the mask layer can be formed, for example, by sheet-cut film or by coating and drying with a treatment solution.

[0023] The shape of the mask portion is not particularly limited, but can be, for example, a stripe shape or a honeycomb shape. In the case of a stripe shape, the width of the opening is not particularly limited, but can be 1 to 200 μm or 2 to 100 μm. The width of the mask portion can be 1 to 200 μm or 2 to 100 μm.

[0024] When the first step includes forming the openings 21 in the mask layer 3, the step of forming the openings is not particularly limited, and known techniques can be used. For example, a method of forming a mask layer using a photosensitive resin and then forming the openings by photolithography can be used. Furthermore, the step of providing the mask layer 3 on the first substrate and the step of forming the openings 21 in the mask layer 3 can be performed simultaneously. For example, a method of printing the mask portion using a highly film-forming ink such as PVA or a vinyl-based material, or a method of printing the mask portion using electrophotography or inkjet technology can be used. The material layer preparation apparatus shown in FIG. 3 uses a UV laser 6 as a means for forming the mask openings. The use of a UV laser allows for a high degree of pattern flexibility. Furthermore, by increasing the difference in wavelength absorptivity between the material of the first substrate and the material of the mask layer, such as by using glass as the first substrate and a resin film as the mask layer, it is possible to remove only the mask layer without damaging the first substrate. The use of a UV laser increases the adhesion of the edges of the mask portion to the first substrate due to the heat generated during processing, thereby reducing unintended peeling of the mask layer.

[0025] 3, the openings are formed after the mask layer is attached to the first substrate 1. Alternatively, the mask layer may have openings formed therein in advance, and then the mask layer may be attached to form the mask.

[0026] In the second step, first particles 22 are disposed on the surface of the first substrate 1. The method for disposing the first particles 22 is not particularly limited and can be selected depending on the particle characteristics and particle density for the desired pattern. The second step is preferably a step of disposing the first particles 22 in an area of ​​the surface of the first substrate 1 where the mask portion 3-1 is not formed. The area where the mask portion 3-1 is not formed is the image area in the design, where the first particles 22 are expected to be disposed. The openings 21 can be considered to be areas of the surface of the first substrate 1 where no mask portion is formed. It is also preferable to consider the fixing force of the mask portion to the first substrate. Excessive shear that may occur when disposing the first particles may cause the mask portion to peel off. The material layer preparation apparatus of Figure 3 uses a magnetic particle rubbing means. The magnetic particle rubbing means has the following advantages. Specifically, by controlling the magnetic force of a sliding magnet (not shown) disposed on the back surface of the first substrate (the surface opposite the side where the mask layer is provided), the shear during particle placement can be easily controlled. According to the present disclosure, the excess particles on the mask portion can be removed together with the removal of the mask portion. Therefore, as a method for disposing the first particles, a low-shear application method such as a method using a forward rotating roller or a vibration powder flow method can be used effectively. Furthermore, the method for disposing the first particles may be used alone or in combination with multiple methods.

[0027] After the first particles are disposed, a process for removing excess first particles may be performed. As described above, in the present disclosure, excess first particles on the mask portion can be removed together with the removal of the mask portion. However, if an excess of particles is filled in the openings, the first particles may slide off during the transfer process. This may result in a disruption of the particle pattern or an increase in the amount of unwanted particle adhesion. The material layer production apparatus of FIG. 3 includes an air blower 8 as a means for removing excess first particles after the first particles 22 are disposed. Air blowing is preferred for removing excess particles. Other known techniques, such as a soft brush or a weakly adhesive roller, may also be used to remove excess first particles.

[0028] In the third step, the mask portion 3-1 is removed from the first substrate 1. The method for removing the mask portion 3-1 from the first substrate 1 is not particularly limited, but examples include peeling the mask portion 3-1 from the first substrate 1. To remove the mask portion 3-1 from the first substrate 1, the material layer preparation device shown in FIG. 3 uses a peeling roller 9 and a winding device 10 to wind the mask portion 3-1 in the form of a continuous film. Other methods include, for example, in the case of a sheet-like mask, vacuum suction of the periphery of the mask, or mechanically lifting up a handle provided at the end of the mask. Furthermore, since static electricity may be generated when removing a mask portion made of a resin material, which may disrupt the particle pattern, it is preferable to take measures against static electricity depending on the situation.

[0029] In the fourth step, the first particles are transferred to a second substrate. After removing the mask portion 3-1, the first particles 22 remain alone on the first substrate 1 (Figure 4E). Therefore, by transferring the first particles by contacting and pressing the second substrate having an adhesive layer on its surface, a second substrate having the first particles on its surface can be obtained. The second substrate is not particularly limited and can be freely selected depending on the purpose. For example, the above-mentioned materials for the first substrate can be used. In the material layer preparation apparatus of Figure 3, a roll of the second substrate in the form of a double-sided tape is used, in which adhesive layers are formed on both sides of the base substrate. That is, the second substrate may be an adhesive tape or a double-sided tape. The method for obtaining a second substrate having an adhesive layer is not particularly limited. For example, a mechanism for applying an adhesive to the surface of the second substrate within the apparatus may be provided. The material used for the adhesive is not particularly limited, and examples include acrylic adhesives, urethane adhesives, and silicone-based adhesives.

[0030] Furthermore, if the second substrate is formed only from an adhesive phase, it may stretch due to the force applied during handling, such as when peeling it off from the intermediate transfer body. Therefore, it is desirable for the second substrate to have a multilayer structure consisting of a base substrate made of a material that is resistant to stretching and an adhesive layer. Materials that can be used for the base substrate include resin films such as polyester resin, acrylic resin, polypropylene resin, and polyimide resin, and metal foils such as aluminum and copper. Considering that the second substrate will be removed by heating, a resin film is preferred.

[0031] The pressure roller 12 used to transfer the first particles to the second substrate is preferably an elastic material. An elastic material allows for stable transfer pressure, resulting in a more stable transfer rate. While the material layer production device shown in FIG. 3 uses a single elastic roller, other configurations, such as a configuration using multiple elastic rollers, belt pressure, or surface pressure applied by batch processing, are also applicable. The particles on the first substrate directly contact the surface of the adhesive layer on the second substrate. Therefore, there is little resistance when separating the first substrate from the second substrate after transfer, and the shear applied to the second substrate is also small. As a result, the substrate is less likely to stretch or wrinkle.

[0032] In the fifth step, second particles are disposed in at least a portion of the surface of the second substrate where the first particles are not disposed. The material layer preparation apparatus of FIG. 3 includes a second particle supply unit 13 for supplying second particles to the second substrate on which the first particles are disposed. Therefore, the second particles can be disposed in the portion where the first particles are not disposed. The first particles are disposed in a portion of the adhesive layer of the second substrate. Therefore, the second particles selectively adhere to the exposed portion of the adhesive layer other than the portion where the first particles are disposed. The means for disposing the second particles can be any of those described in the first particle column. When a material layer without second particles is to be produced, the method for producing the material layer does not need to include the fifth step. That is, the method for producing the material layer may include the first step, the second step, the third step, and the fourth step. The second particles may be the same as or different from the first particles.

[0033] While the material layer preparation apparatus in Figure 3 illustrates an example using two types of particles, first particles and second particles, the present disclosure also allows for the production of patterns with three or more types of particles. First, first particles 22 on a first substrate are transferred to a second substrate 11 (Figure 5A). In Figure 5, the second substrate comprises a base substrate 23 and an adhesive layer 24 on the base substrate. Third particles 25 are then placed on another first substrate using the same method as the first particles (Figures 5B and 5C). This is then transferred to the second substrate 11, after which second particles 26 are applied. This results in the second particles 26 selectively adhering to the exposed areas other than those where the first particles 22 and third particles 25 are placed (Figure 5D). Therefore, by using a mask designed with offset opening patterns, a pattern consisting of more types of particles can be obtained. In other words, it is preferable to perform the first process two or more times, with the shapes of the mask portions formed in each process being different. Here, the third particles can be similar to the first particles described below.

[0034] The material layer preparation apparatus of Figure 3 can produce a single-layer particle pattern. On the other hand, this single-layer particle pattern can also be stacked to form a laminate. That is, a laminate may be manufactured by a process of stacking material layers to obtain a laminate. The second substrate on which a particle pattern is formed, prepared using the material layer preparation apparatus of Figure 3, is in the form of double-sided tape. Therefore, sheets can be stacked using the adhesive layer on the opposite side of the layer on which the particle pattern is formed (Figure 6A). That is, a laminate 601 can be formed by stacking multiple second substrates on which a particle layer is formed. Here, by having an adhesive layer on the opposite side of the layer on which the particle pattern is formed, the substrates adhere to each other, increasing the strength of the laminate. As a result, misalignment between the substrates can be suppressed. Furthermore, by sandwiching the particle layer between the substrates between the upper and lower adhesive layers, misalignment during storage, etc., can be suppressed. The number of layers in the laminate is not particularly limited.

[0035] Furthermore, by utilizing the difference in properties between the particles used and the second substrate, the second substrate can be removed to obtain a patterned laminate (three-dimensional object 602) consisting only of particles (Figure 6B). That is, a three-dimensional object may be manufactured by removing the second substrate from the laminate and molding a three-dimensional object containing particles. The method for removing the second substrate is not particularly limited. For example, a patterned laminate consisting only of particles can be obtained by forming a material layer on the second substrate using a resin material and then degreasing the laminate made from the material layer at a high temperature. Furthermore, by using a second substrate containing ceramic particles and particles that can be degreased by heating, the internal porosity of the ceramic structure can be controlled.

[0036] The conditions for high-temperature degreasing are not particularly limited, but it is preferable to heat at a temperature equal to or higher than the thermal decomposition temperature of the second substrate, and preferably at a temperature lower than the thermal decomposition temperature of each particle layer in the pattern laminate. 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. The upper limit is not particularly limited, but 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 the material begins to decrease when the temperature is gradually increased in the heating atmosphere in the sintering treatment device. Therefore, by heating the laminate at a temperature equal to or higher than the thermal decomposition temperature of the second substrate, the second substrate in the laminate can be decomposed to reduce its weight, and the second substrate can be removed from the laminate.

[0037] This invention can be applied to a wide range of functional materials, but is particularly suited to battery modules. Battery materials are expected to achieve high performance by functionally arranging the materials in the electrode layers and efficiently arranging the paths of ions and electrons. In particular, all-solid-state batteries, which do not use electrolytes, are particularly effective at functionally arranging positive and negative electrode materials and solid electrolyte materials.

[0038] The first particles are not particularly limited, and any desired resin particles, inorganic particles, etc. can be used. Examples of resin particles include (meth)acrylic resin particles, urethane resin particles, and ester resin particles. When the method for manufacturing a material layer according to the present disclosure is used as a method for manufacturing a precursor for a solid-state battery, it is preferable that the first particles include at least one of active material particles and solid electrolyte particles, for example.

[0039] The active material particles are not particularly limited, and known active material particles can be used. For example, a composite oxide containing lithium can be used. Specifically, for example, LiCoO ２ Li-Co oxide active material particles such as (lithium cobalt oxide), LiMO ２ (M is an element selected from the group consisting of Ni, Mn, and Co), ４ Oxide-based active material particles, lithium vanadium compounds (Li ３ V ２ (P.O. ４ ) ３ , LiVOPO ４ ), olivine-type phosphate compounds (LiMPO ４ (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 may also be used. Specifically, for example, metal oxides (MnO ２ , V ２ O ５ etc.) and fluorides (FeF ３ , V.F. ３ Among them, Li-Co oxide-based active material particles, Li-PO ４ It is preferable that the negative electrode active material contains oxide-based particles. Alternatively, negative electrode active material particles such as graphite, Si, and lithium titanate (LTO) can also be used.

[0040] The solid electrolyte is not particularly limited, and known solid electrolytes can be used. For example, Li-B oxide-based solid electrolyte particles, Li-Yb oxide-based solid electrolyte particles, Nasicon-type solid electrolyte particles (LiAlTi(PO ４ ) ３ , LiAlGe (PO４ ) ３ etc.), Li-P-O solid electrolyte particles (Li ３ P.O. ４ , LiPON (Li ３ P.O. ４ and the like) in which part of O is substituted with N. Among the above solid electrolyte particles, Li—B oxide-based solid electrolyte particles and Li—Yb oxide-based solid electrolyte particles are preferred.

[0041] The second particles are not particularly limited, and as with the first particles, desired resin particles, inorganic particles, etc. can be used. When the method for manufacturing a material layer of the present disclosure is used as a method for manufacturing a precursor for a solid-state battery, the second particles preferably include, for example, at least one of active material particles and solid electrolyte particles. Specifically, the active material particles and solid electrolyte particles described above as the first particles can be used.

[0042] The first particles and the second particles may each be used alone or in combination of two or more types. When two or more types are used in combination, the two or more types of particles may be premixed in advance. The particle surfaces may be subjected to a surface treatment or coating.

[0043] The method for manufacturing a material layer according to the present disclosure can be used as a method for manufacturing a precursor for a solid-state battery. Specifically, the method for manufacturing a precursor for a solid-state battery includes a first step of forming a mask portion on a portion of the surface of a first substrate, a second step of disposing first particles on the surface of the first substrate, a third step of removing the mask portion from the first substrate, a fourth step of transferring the first particles to a second substrate, and a fifth step of disposing second particles on at least a portion of the surface of the second substrate where the first particles are not disposed. The resulting material layer corresponds to a precursor for a solid-state battery. Using the method for manufacturing a material layer according to the present disclosure as a method for manufacturing a precursor for a solid-state battery reduces the amount of unwanted particle adhesion, improves the particle transfer rate when transferring the first particles to the second substrate, and reduces the fluctuation range of the electrical resistance value described below. When manufacturing a precursor for a solid-state battery that does not have second particles, the method for manufacturing a precursor for a solid-state battery does not need to include the fifth step. That is, the method for manufacturing a precursor of a solid state battery may be a method for manufacturing a precursor of a solid state battery including the first step, the second step, the third step, and the fourth step.

[0044] When the method for manufacturing a material layer according to the present disclosure is used as a method for manufacturing a precursor for a solid-state battery, the second substrate is preferably a resin substrate. Furthermore, it is preferable that the first particles include at least one of active material particles and solid electrolyte particles, and the second particles include at least one of active material particles and solid electrolyte particles. More preferably, the first particles include at least one of active material particles and solid electrolyte particles, and the second particles include the other of active material particles and solid electrolyte particles. Even more preferably, the first particles include active material particles, and the second particles include solid electrolyte particles.

[0045] Furthermore, a vibration absorber can be obtained by using at least one of strong elastic particles and weak elastic particles as the first particles and the other of strong elastic particles and weak elastic particles as the second particles. The obtained vibration absorber has specificity with respect to the vibration direction.

[0046] An example of a precursor for a solid-state battery is a material layer for a solid-state battery. A material layer for a solid-state battery can be used as a precursor for a solid-state battery to obtain a material laminate in which material layers for a solid-state battery are stacked. The precursor for a solid-state battery is preferably a material layer for an electrode of a solid-state battery. Therefore, a method for manufacturing an electrode for a solid-state battery may include a step of obtaining a material layer by the above-described manufacturing method, a step of stacking the obtained material layers to obtain a laminate, and a step of thermally degreasing the obtained laminate to remove the second substrate and obtain an electrode. When the solid-state battery is a single layer, a method for manufacturing an electrode for a solid-state battery may include a step of obtaining a material layer by the above-described manufacturing method, and a step of thermally degreasing the material layer to remove the second substrate and obtain an electrode.

[0047] That is, by removing the second substrate from the laminate, an electrode for a solid-state battery can be obtained. The above-mentioned processes can be used for the process of obtaining the laminate and the process of forming a three-dimensional object. The electrode may be a positive electrode or a negative electrode. The number of layers of the laminate is not particularly limited and can be changed depending on the purpose of the electrode to be manufactured. For example, three or more layers can be used.

[0048] The present disclosure will be specifically described below with reference to examples, but these examples are not intended to limit the present disclosure in any way. In the following formulations, parts are by mass unless otherwise specified.

[0049] Example 1: This example shows the fabrication of a positive electrode material layer for an all-solid-state battery using the material layer fabrication apparatus shown in Figure 3. The first particles were a positive electrode material: lithium cobalt oxide (manufactured by Nippon Chemical Industry Co., Ltd.: average particle size 5 μm), the second particles were a solid electrolyte: lithium borate (manufactured by Toshima Manufacturing Co., Ltd.: particle size target 5 μm), the first substrate was borosilicate glass (manufactured by Hoya Corporation: 5 mm thick), and the mask layer was a polyester film (manufactured by Toray Industries, Inc.: Lumirror 5 μm thick). A UV laser processing machine (manufactured by Kokyo Co., Ltd.: fine UV laser marker), double-sided tape (manufactured by Nitto Denko Corporation: No. 5600) was used for the second substrate, and magnetic particles (Japan Imaging Society: P02) were used for the particle supply unit. Then, steps 1 to 5 described above were performed using the material layer fabrication apparatus shown in Figure 3 to fabricate a positive electrode material layer for an all-solid-state battery. The opening pattern of the mask was a 10 μm stripe pattern with lines and spaces, that is, the openings were 10 μm wide and the mask portion was a stripe pattern with a 10 μm width and a 20 μm pitch.

[0050] Five of the prepared positive electrode material layers were laminated on an aluminum foil (20 μm thick) with the lamination angle shifted by 90 degrees, and then the laminate was degreased by heating at 500°C for 1 hour in an electric furnace (MMF-1 manufactured by AS ONE Corporation), and the second substrate was removed to prepare a positive electrode material layer laminate (thickness: approximately 25 μm) for an all-solid-state battery.

[0051] The following three items were measured to evaluate the material layer and the laminate. <Amount of Unwanted Particle Adhesion> The area ratio of the first particles adhering to areas that were designed as non-image areas (areas where the mask area was removed) immediately before the transfer of the particle pattern (after the third process) was optically observed. Then, the area ratio of the first particles in the non-image areas was calculated using image processing software (Adobe Systems: Photoshop (registered trademark)). A total of 10 similar material layers were produced, and the arithmetic average value of the obtained area ratios of the first particles was taken as the amount of unwanted particle adhesion. The amount of unwanted particle adhesion was 0 area %.

[0052] <Particle Transfer Rate> The mass of the first particles adhered to the second substrate after transfer and the mass of the first particles held on the first substrate immediately before transfer were each measured using an AS ONE electronic balance. Both values ​​were valid to four decimal places, and the fifth decimal place was rounded off. The value was then calculated using the following formula: Mass (g) of the first particles adhered to the second substrate after transfer / Mass (g) of the first particles held on the first substrate immediately before transfer × 100. A total of 10 similar material layers were produced, and the arithmetic mean value of the values ​​obtained by the above formula was used as the particle transfer rate. The particle transfer rate was 99.2%.

[0053] <Fluctuation Range of Electrical Resistance in the Thickness Direction of Positive Electrode Material Layer Laminate> The fluctuation range of the electrical resistance in the thickness direction of the obtained positive electrode material layer laminate was measured. A Solartron 1255WB model was used as the electrochemical device. A total of 10 similar laminates were produced, and the electrical resistance values ​​of each were measured using the electrochemical device. The arithmetic mean value of the obtained electrical resistance values ​​was calculated. Then, of the electrical resistance values ​​of the total 10 laminates, the electrical resistance value A that was the most different from the obtained arithmetic mean value and the arithmetic mean value were used to calculate the fluctuation range of the electrical resistance value according to the following formula: |Electrical Resistance Value A (Ω) - Arithmetic Mean Value of Electrical Resistance Values ​​(Ω)| / Arithmetic Mean Value of Electrical Resistance Values ​​(Ω) × 100 The fluctuation range of the electrical resistance value was 1.75%.

[0054] According to the above evaluation, no transfer defects were observed in the produced material layers, and the quality of the produced laminates was stable.

[0055] [Comparative Example 1] An all-solid-state battery positive electrode material layer was produced under the same conditions as in Example 1, except that no first substrate or mask layer was used, and instead a glass intaglio plate was used that was prepared by patterning borosilicate glass (HOYA: 5 mm thick) with a photoresist and then dry etching to the same pattern (plate depth 5 μm) as in Example 1. In addition, a positive electrode material layer laminate for an all-solid-state battery was produced under the same conditions as in Example 1. Evaluations were then performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

[0056] Example 2: This example shows the fabrication of a vibration-absorbing rubber material layer using the material layer fabrication device shown in Figure 3. The first particles were highly elastic particles: crosslinked polyacrylate ester (manufactured by Sekisui Chemical Co., Ltd.: ARX-30), the second particles were weakly elastic particles: crosslinked acrylic monodisperse particles (manufactured by Soken Chemical & Engineering Co., Ltd.: MX-3000), the first substrate was borosilicate glass (manufactured by Hoya Corporation: 5 mm thick), and the mask layer was made of SUS430 (30 μm thick). A CO2 laser processing machine (manufactured by Kokyosha) was used to fabricate the mask openings, double-sided tape (manufactured by Nitto Denko Corporation: No. 5600) was used for the second substrate, and a forward-rotating roller unit equipped with a urethane rubber roller (rubber hardness 70 degrees) was used as the particle supply unit. Then, steps 1 to 5 described above were performed using the material layer fabrication device shown in Figure 3 to fabricate a vibration-absorbing rubber material layer. The opening pattern of the mask was a 100 μm stripe pattern with lines and spaces, i.e., the openings were 100 μm wide and the mask portion was a stripe pattern of 100 μm wide and 200 μm pitch. Furthermore, during the first to third steps, a magnet was placed on the back surface of the intermediate transfer body, and the mask layer and mask portion were held in place by magnetic force.

[0057] The material layer was evaluated by evaluating the amount of unwanted particle adhesion and the particle transfer rate. The results are shown in Table 2. No transfer defects were observed in the fabricated material layer, and stable quality was obtained. Furthermore, a vibration-absorbing rubber material laminate obtained by repeatedly stacking 150 layers of the fabricated vibration-absorbing rubber material layers in the order of 0°, 0°, and 90° was able to be manufactured with stable quality as a vibration absorber with specificity in the vibration direction. Here, specificity in the vibration direction means that the amount of deformation when the laminate is subjected to vibration is not isotropic. Specifically, the amount of deformation in the longitudinal direction of the stripe pattern was small relative to the vibration direction, while the amount of deformation in the transverse direction was large relative to the vibration direction.

[0058] A vibration-absorbing rubber material layer was produced under the same conditions as in Example 2, except that a first substrate and a mask layer were not used, and a PDMS intaglio plate (produced in-house) was used, which was produced by casting a master mold processed on a precision lathe into the same pattern (plate depth 30 μm) as in Example 2. Evaluations were also carried out in the same manner as in Example 2. The evaluation results are shown in Table 2.

[0059] According to the present disclosure, a method for manufacturing a material layer that contributes to stabilizing manufacturing quality and improving the yield rate is provided. Also, according to the present disclosure, a method for manufacturing a precursor of a solid-state battery that contributes to stabilizing manufacturing quality and improving the yield rate is provided.

[0060] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to clarify the scope of the present disclosure. This application claims priority based on Japanese Patent Application No. 2024-009194, filed January 25, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A method for manufacturing a material layer, comprising: a first step of forming a mask portion on a part of the surface of a first substrate; a second step of disposing first particles on the surface of the first substrate; a third step of removing the mask portion from the first substrate; a fourth step of transferring the first particles to a second substrate; and a fifth step of disposing second particles on at least a part of a region on the surface of the second substrate where the first particles are not disposed.

2. The method for manufacturing a material layer according to claim 1, wherein the first step includes a step of providing a mask layer on the first substrate and a step of forming an opening in the mask layer to form the mask portion.

3. The method for manufacturing a material layer according to claim 1 or 2, wherein the second step is a step of disposing first particles on a region of the surface of the first substrate where the mask portion is not formed.

4. The method for manufacturing a material layer according to any one of claims 1 to 3, wherein the first particles include at least one of active material particles and solid electrolyte particles, and the second particles include at least one of active material particles and solid electrolyte particles.

5. A method for manufacturing a precursor of a solid battery, including the method for manufacturing a material layer according to claim 4, wherein the second substrate is a resin substrate.

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