Apparatus and method for manufacturing liquid compositions, containment containers, and solid electrolyte layers or electrode composite layers.

Abstract

To provide a liquid composition that can suppress the generation of hydrogen sulfide and have high dispersibility of an inorganic solid electrolyte while containing a high concentration of an inorganic solid electrolyte, and can be discharged by an inkjet method.SOLUTION: A liquid composition includes a solvent, an inorganic solid electrolyte, and a dispersant, and the solvent is one type of liquid composition that has a vapor pressure of 0.1 hPa or more and 1.0 hPa or less at 25°C, and is at least selected from the group consisting of (I) an aliphatic hydrocarbon, (II) a monoether, and (III) an ester having a branched structure.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid composition, a container, and an apparatus and method for manufacturing a solid electrolyte layer or electrode composite layer. [Background technology]

[0002] Electrochemical elements such as lithium-ion secondary batteries, lithium-ion capacitors, electric double-layer capacitors, and redox capacitors are widely used in electronic devices, electric vehicles, and other applications. In particular, the demand for lithium-ion secondary batteries for automotive use is expected to expand in recent years, driven by the growing need for low environmental impact. Against this backdrop, there is a demand for further improvements in the safety and energy density of lithium-ion secondary batteries, and efforts to commercialize all-solid-state batteries, which replace the existing liquid electrolyte with a solid electrolyte, are thriving.

[0003] The manufacturing process for the solid electrolyte layer in all-solid-state batteries is broadly classified into dry processes and wet processes. The dry process involves arranging dried solid electrolyte powder particles in a sheet shape and obtaining a sheet-like solid electrolyte layer by pressing and sintering. The wet process involves coating the layer with a liquid composition obtained by mixing the solid electrolyte in a solvent. From the viewpoint of productivity, the wet process is preferred.

[0004] Furthermore, among wet processes, inkjet printing coating processes, which allow for precise coating control and contribute to increased flexibility and efficiency in solid-state battery shape design, are highly effective from the perspective of future battery shape flexibility and high-efficiency production.

[0005] Furthermore, from the perspective of improving production efficiency, it is conceivable to increase the solid content concentration of the slurry containing the solid electrolyte when forming the solid electrolyte layer.

[0006] For example, as a technique aimed at suppressing a decrease in the ionic conductivity of a solid electrolyte, a technique using a specific solvent has been proposed (see, for example, Patent Document 1). It is also described in the proposed technique that by using the solvent, a composition excellent in slurry retention and slurry coatability can be obtained.

[0007] Further, as a technique aimed at improving the production efficiency of all-solid-state secondary batteries and the like by having excellent dispersibility, a solid electrolyte composition including a polymer containing a constituent component derived from a macromonomer satisfying predetermined conditions and a dispersion medium has been proposed (see, for example, Patent Document 2).

[0008] Also, as a technique aimed at providing a solid electrolyte or the like that can maintain a slurry state for a certain period of time when mixed with a liquid, a technique using solid electrolyte particles having a predetermined particle size has been proposed (see, for example, Patent Document 3).

[0009] In addition, efforts have been made to suppress the generation of hydrogen sulfide and the formation of sulfur oxides and the like in the manufacturing process by using a low-polarity hydrocarbon-based solvent or the like (see, for example, Patent Document 4).

Summary of the Invention

Problems to be Solved by the Invention

[0010] An object of the present invention is to provide a liquid composition that can contain an inorganic solid electrolyte at a high concentration, while achieving both suppression of the generation of hydrogen sulfide and high dispersibility of the inorganic solid electrolyte, and can be discharged by an inkjet method.

Means for Solving the Problems

[0011] The liquid composition of the present invention, as a means for solving the aforementioned problems, is a liquid composition comprising a solvent, an inorganic solid electrolyte, and a dispersant, wherein the solvent is at least one selected from the group consisting of (I) aliphatic hydrocarbons, (II) monoethers, and (III) esters having a branched structure, and having a vapor pressure of 0.1 hPa or more and 1.0 hPa or less at 25°C. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a liquid composition that contains a high concentration of inorganic solid electrolyte while simultaneously suppressing the generation of hydrogen sulfide and achieving high dispersibility of the inorganic solid electrolyte, and that can be dispensed by an inkjet method. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic diagram showing an example of a manufacturing apparatus for a solid electrolyte layer or electrode composite layer to realize the manufacturing method of the solid electrolyte layer or electrode composite layer of this embodiment. [Figure 2] Figure 2 is a schematic diagram showing another example of a manufacturing apparatus (liquid dispensing apparatus) for a solid electrolyte layer or electrode composite layer to realize the manufacturing method of the solid electrolyte layer or electrode composite layer of this embodiment. [Figure 3] Figure 3 is a schematic diagram showing an example of an energy storage element provided with a solid electrolyte layer according to this embodiment. [Modes for carrying out the invention]

[0014] (liquid composition) One embodiment of the liquid composition of the present invention comprises a solvent, an inorganic solid electrolyte, and a dispersant, and optionally further comprises other components (hereinafter sometimes referred to as "the first embodiment"). Another embodiment of the liquid composition of the present invention is a liquid composition ejected using an inkjet head, comprising a solvent, an inorganic solid electrolyte, and a dispersant, and optionally further comprising other components (hereinafter sometimes referred to as "the second embodiment").

[0015] As mentioned above, from the viewpoint of productivity, a wet process is preferred for manufacturing the solid electrolyte layer in all-solid-state batteries. However, inorganic solid electrolytes, especially sulfide solid electrolytes containing sulfur elements, react not only with water but also with organic solvents to generate harmful hydrogen sulfide, thus limiting the solvents that can be used in wet coating processes.

[0016] Furthermore, from the perspective of improving production efficiency, it is conceivable to increase the solid content concentration of the slurry containing the inorganic solid electrolyte when forming the solid electrolyte layer. However, increasing the solid content concentration of the inorganic solid electrolyte in the liquid composition can lead to aggregation of the inorganic solid electrolyte or an increase in viscosity. Although various studies have been conducted in conventional technologies as described above, it has been difficult to suppress aggregation, maintain dispersibility, and achieve inkjet ejection performance even when inorganic solid electrolytes (hereinafter sometimes referred to as "ion-conducting materials") are contained at high concentrations. Furthermore, with some solvents, while inkjet ejection itself was possible, there was a problem where the ink in the ejection unit would dry out and clog when ejection was stopped and then restarted.

[0017] The present inventors have found that by using a liquid composition comprising a solvent, an inorganic solid electrolyte, and a dispersant, wherein the solvent is at least one selected from the group consisting of (I) aliphatic hydrocarbons, (II) monoethers, and (III) esters having a branched structure, and having a vapor pressure of 0.1 hPa or more and 1.0 hPa or less at 25°C, it is possible to suppress the generation of hydrogen sulfide and the aggregation of the inorganic solid electrolyte even in a liquid composition containing a high concentration of inorganic solid electrolyte, thereby improving the dispersibility of the liquid composition and obtaining an inkjet-dispensable liquid composition.

[0018] In this specification, "capable of ejection by inkjet method" means that ejection is performed from one nozzle (nozzle diameter: 40 μm) of the inkjet head using the droplet observation device EV1000 (manufactured by Ricoh Co., Ltd.) and the ejection state can be maintained for 60 seconds or more. Maintaining the ejection state for 60 seconds or more means that the liquid composition is being ejected at least 60 seconds after the start of ejection, regardless of the amount ejected. That is, as long as the liquid composition is being ejected at least 60 seconds after the start of ejection, the amount ejected may or may not change between the start of ejection and 60 seconds after the start of ejection.

[0019] Furthermore, in this specification, "re-ejectable by inkjet method" means that when ejection is performed from one nozzle (nozzle diameter: 40 μm) of the inkjet head using a droplet observation device EV1000 (manufactured by Ricoh Co., Ltd.), the ejection state is maintained for 60 seconds, then left to stand for 5 minutes, and then ejection is performed again, the material can be re-ejected.

[0020] <Solvent> -First aspect- The solvent in the first embodiment comprises at least one selected from the group consisting of (I) aliphatic hydrocarbons, (II) monoethers, and (III) esters having a branched structure, having a vapor pressure of 0.1 hPa or more and 1.0 hPa or less at 25°C. Since the liquid composition using the solvent having a vapor pressure of 0.1 hPa or more and 1.0 hPa or less at 25°C has sufficiently low evaporative properties, it is possible to suppress clogging of the ejection port due to drying during inkjet ejection. Furthermore, since at least one selected from the group consisting of (I) aliphatic hydrocarbons, (II) monoethers, and (III) esters having a branched structure is used, it is possible to suppress the deterioration of the inorganic solid electrolyte when preparing the liquid composition, and since it has high dispersibility, it is possible to suppress particle aggregation. The aforementioned solvent may be used alone or in combination of two or more. When using a mixed solvent consisting of two or more solvents, it should be determined whether the vapor pressure of each solvent at 25°C is between 0.1 hPa and 1.0 hPa.

[0021] The vapor pressure of the aforementioned solvent at 25°C can be found in the Safety Data Sheet (SDS) for the solvent, if available. For solvents not listed in the SDS, the vapor pressure can be measured using the isotenoscope method described in "Research on Understanding the Physicochemical Properties of Chemical Substances" (1986 / Published by the Japan Environmental Association / Authored by the Health Investigation Office, Environmental Health Department, Environment Agency).

[0022] The vapor pressure of the solvent at 25°C is not particularly limited as long as it is between 0.1 hPa and 1.0 hPa, and can be appropriately selected depending on the purpose. However, from the viewpoint of preventing drying, it is preferable that it be between 0.1 hPa and 0.5 hPa.

[0023] [(I) Aliphatic hydrocarbons] The above (I) is a solvent having an aliphatic hydrocarbon structure. Due to its structure, aliphatic hydrocarbons have a sufficiently low reactivity with sulfide solid electrolytes, and therefore have little effect on ionic conductivity after coating. The aliphatic hydrocarbon may or may not have branched chains.

[0024] The carbon number of the aliphatic hydrocarbon (I) is not particularly limited and can be appropriately selected depending on the purpose, but it is preferably in the range of 11 to 14. When it is within this preferred range, clogging due to drying of the print head during inkjet coating can be suppressed, and clogging in the inkjet process can also be suppressed because the viscosity of the solvent does not become high.

[0025] Examples of the aliphatic hydrocarbons (I) mentioned above include undecane, dodecane, tridecane, tetradecane, cycloundecane, cyclododecane, cyclotridecane, cyclotetradecane, and 2-butyloctane, and more preferably undecane, tridecane, tetradecane, and 2-butyloctane.

[0026] [(II) Monoether] The above (II) is a solvent having a monoether structure. This is because polyether structures of diether or higher have high reactivity with sulfide solid electrolytes, making it impossible to obtain a stable ink.

[0027] There are no particular restrictions on the number of molecules that constitute the basic framework of the (II) monoether, and they can be appropriately selected depending on the purpose, but it is preferable that they be in the range of 11 to 13. If the number is within this preferred range, it is possible to suppress clogging due to drying of the print head during inkjet coating, and also, since the boiling point of the solvent does not exceed 250°C, it is possible to prevent excessive energy from being required for the drying process after inkjet printing.

[0028] Examples of the (II) monoethers include butylphenyl ether, pentylphenyl ether, hexylphenyl ether, dipentyl ether, and dihexyl ether, with butylphenyl ether and dihexyl ether being more preferred.

[0029] [(III) Esters with a branched structure] The above (III) is a solvent having an ester structure with a branched structure.

[0030] The (III) ester having a branched structure is preferably one of the following: (i) an ester in which a hydrocarbon group having 2 or fewer carbon atoms is bonded to the carbon side of the ester group and a hydrocarbon group having a branched structure is bonded to the oxygen side of the ester group; or (ii) an ester in which a hydrocarbon group having 3 or fewer carbon atoms is bonded to the oxygen side of the ester group and a hydrocarbon group having a branched structure is bonded to the carbon side of the ester group.

[0031] In the case of the ester described in (i) above, since the group bonded to the carbon of the ester group is a hydrocarbon group (methyl group or ethyl group) with 2 or fewer carbon atoms, the compound size can be suppressed, the viscosity can be sufficiently low, and inkjet ejection is good. Furthermore, because the group bonded to the oxygen of the ester group has a branched structure, the reactivity of the ester group is suppressed due to steric hindrance, and a stable solid electrolyte film can be provided without reacting with the inorganic solid electrolyte. In the ester of (i) above, the group that bonds with the oxygen of the ester group is preferably a hydrocarbon group having 3 or more carbon atoms and a branched structure.

[0032] In the case of the ester described in (ii) above, since the group that bonds with the oxygen of the ester group is a hydrocarbon group having 3 or fewer carbon atoms, the compound size can be suppressed, the viscosity can be sufficiently low, and inkjet ejection is good. Furthermore, because the group that bonds with the carbon of the ester group has a branched structure, the reactivity of the ester group is suppressed due to steric hindrance, and a stable solid electrolyte film can be provided without reacting with the inorganic solid electrolyte.

[0033] Note that the carbon side of the ester group (the group that bonds with the carbon of the ester group) is "R" in the following formula (A), and the oxygen side of the ester group (the group that bonds with the oxygen of the ester group) is "R'" in the following formula (A). [ka]

[0034] Examples of esters having the branched structure (III) above include isooctyl acetate, 2-ethylhexyl acetate, 2-nonyl acetate, and 2-ethylhexyl propionate, with 2-nonyl acetate, 2-ethylhexyl acetate, and 2-ethylhexyl propionate being more preferred.

[0035] The solvent may be one or more solvents having a structure selected from the group consisting of (I), (II), and (III), and can be used as a mixture of these two or more. There are no particular restrictions on the mass ratio when two or more of the aforementioned solvents are used in combination; they can be appropriately selected according to the purpose.

[0036] It is preferable to use a dehydrated solvent. There are no particular restrictions on the degree of dehydration, and it can be appropriately selected depending on the purpose, but it is preferable that the water content measured by a Karl Fischer moisture meter is 1,000 ppm or less, more preferably 100 ppm or less, and even more preferably 10 ppm or less.

[0037] -Second aspect- The solvent in the second embodiment is the same as the solvent in the first embodiment described above.

[0038] <Inorganic solid electrolyte> -First aspect- The inorganic solid electrolyte in the first embodiment is not particularly limited as long as it does not have electronic conductivity but has ionic conductivity. Among the inorganic solid electrolytes, sulfide solid electrolytes containing sulfur in their compositional formula or oxide solid electrolytes containing oxygen as an anion are preferred from the viewpoint of ionic conductivity, and sulfide solid electrolytes are more preferred because they have high plasticity and can form good interfaces between solid electrolyte particles or between the solid electrolyte and the active material. The inorganic solid electrolyte may be one type or two or more types and can be used as appropriate.

[0039] --Sulfide solid electrolyte-- The sulfide-based inorganic solid electrolyte is preferably a compound that contains a sulfur atom (S), has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and is also an electronically insulating compound.

[0040] The aforementioned sulfide solid electrolytes can be broadly classified into crystalline sulfide solid electrolytes and glass solid electrolytes. The crystalline sulfide solid electrolyte is not particularly limited and can be appropriately selected depending on the purpose, for example, Li 9.54 Si 1.74 P 1.44 S11.7 Cl 0.3 、Li 9.6 P3S 12 、Li9P3S9O3、Li 9.81 Sn 0.81 P 2.19 S 12 、Li 9.42 Si 1.02 P 2.1 S 9.96 O 2.04 、Li 10 Ge(P 1-x Sb x )2S 12 (0≦x≦0.15)、Li 10 SnP2S 12 、Li 10.35 [M1 1-x M2 x 1.35 P 1.65 S 12 (M1 and M2 are any of Si, Ge, Sn, As, and Sb, 0≦x≦0.15), Li 11 Si2PS 12 、Li 11 AlP2S 12 、Li 3.45 Si 0.45 P 0.55 S4, Li6PS5X (X is any of Cl, Br, and I), Li5PS4X2 (X is any of Cl, Br, and I), Li 5.5 PS 4.5 Cl 1.5 、Li 5.35 Ca 0.1 PS 4.5 Cl 1.55 、Li 6+x M x Sb 1-x S5I (M is any of Si, Ge, and Sn, 0≦x≦1), Li7P2S8I, γ-Li3PS4, Li4MS4 (M is any of Ge, Sn, and As), Li 4-x Sn 1-x Sb x S4(0≦x≦0.15), Li 4-x Ge 1-x P x S4(0≦x≦0.15), Li 3+5x P 1-x ​Examples include S4 (0 ≤ x ≤ 0.3). The glassy sulfide solid electrolyte is not particularly limited and can be appropriately selected depending on the purpose. Examples include Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-P2O5, Li2S-P2S5-LiCl, Li2S-SiS2, Li2S-SiS2-P2S5, Li2S-SiS2-Al2S3, and Li2S-SiS2-Li x MO y Examples include (where M is one of Si, P, and Ge). Also, Li7P3S, in which a portion of the glassy sulfide solid electrolyte has crystallized. 11 Glass ceramics can also be used. The mixing ratio of each raw material in the glass-based sulfide solid electrolyte is not specified.

[0041] --Oxide solid electrolyte-- The oxide-based inorganic solid electrolyte is preferably a compound that contains oxygen (O), has the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table, and is also an electronically insulating compound.

[0042] The aforementioned oxide solid electrolytes can be broadly classified into crystalline oxide solid electrolytes and glassy oxide solid electrolytes. The crystalline oxide solid electrolyte is not particularly limited and can be appropriately selected depending on the purpose, for example, Li 1+x M x Ti 2-x (PO4)3(M is one of Al, Cr, Ga, Fe, Sc, In, Lu, Y, and La, 0≦x≦0.5), La x Li y TiO3(0.3≦x≦0.7, 0.3≦y≦0.7), Li 7-x La3Zr 2-x M x O 12 Examples include (where M is either Nb or Ta, and 0 ≤ x ≤ 1). The glass oxide solid electrolyte is not particularly limited and can be appropriately selected depending on the purpose. Examples include Li4SiO4-Li2BO3, Li3BO3-Li2SO4, Li2O-B2O3-P2O5, and Li2O-SiO2.

[0043] The inorganic solid electrolyte may be prepared by a known method or may be a commercially available product.

[0044] There are no particular restrictions on the content of the inorganic solid electrolyte in the liquid composition, and it can be appropriately selected depending on the purpose. However, the solid content concentration of the inorganic solid electrolyte is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more. There are no particular restrictions on the upper limit, and it can be appropriately selected depending on the purpose, but it is preferably 60% by mass or less. Being within the above preferred range is advantageous in that it results in better productivity.

[0045] -Second aspect- The inorganic solid electrolyte in the second embodiment is the same as the inorganic solid electrolyte in the first embodiment described above.

[0046] <Dispersant> -First aspect- The dispersant in the first embodiment is not particularly limited as long as it does not react easily with the inorganic solid electrolyte and can disperse the inorganic solid electrolyte, and conventionally known or commercially available dispersants can be appropriately selected depending on the purpose. The dispersant may be used alone or two or more in combination.

[0047] The dispersant is preferably soluble in the solvent. In this specification, "dissolving in the solvent" means that the dispersant is compatible with the solvent. More specifically, if 3% by mass of the dispersant is added to the solvent, dissolved, and then allowed to stand for 10 minutes, and no precipitate or supernatant is observed, it can be determined that the dispersant has dissolved.

[0048] Specific examples of the aforementioned dispersants include, for example, polymeric dispersants such as polyethylene-based, polyethylene oxide-based, polypropylene oxide-based, polycarboxylic acid-based, naphthalene sulfonic acid formalin condensate-based, polyethylene glycol-based, polycarboxylic acid partial alkyl ester-based, polyether-based, polyethyleneimine-based, and polyalkylene polyamine-based; low molecular weight dispersants such as alkyl sulfonic acid-based, quaternary ammonium-based higher alcohol alkylene oxide-based, polyhydric alcohol ester-based, and alkyl polyamine-based; and inorganic dispersants such as polyphosphate dispersants.

[0049] There are no particular restrictions on the content of the dispersant in the liquid composition, and it can be appropriately selected depending on the purpose. However, the solid content concentration of the dispersant is preferably 10% by mass or less relative to the solid electrolyte to be dispersed. If it is outside this preferred range, there is a concern that aggregation will occur due to an excessively high dispersant concentration.

[0050] -Second aspect- The dispersant in the second embodiment is the same as the dispersant in the first embodiment described above.

[0051] <Other ingredients> Other components in the liquid composition in the first and second embodiments described above are not particularly limited as long as they do not impair the effects of the present invention and can be appropriately selected depending on the purpose. Examples include known components used in solid electrolyte layers or electrode composite layers. Specifically, these include binders, active materials, and conductive additives. These may be used individually or in combination of two or more. There are no particular restrictions on the content of the other components in the liquid composition, and they can be appropriately selected depending on the purpose.

[0052] -binder- The binder is not particularly limited as long as it can bind the inorganic solid electrolytes together, or the inorganic solid electrolyte to the substrate or electrode active material, and can be appropriately selected according to the purpose. Examples include polymer compounds and polymer particles. These may be used individually or in combination of two or more.

[0053] The aforementioned polymer compounds are not particularly limited and can be appropriately selected depending on the purpose. Examples include polyamide compounds, polyimide compounds, polyamide-imides, ethylene-propylene-butadiene rubber (EPBR), styrene-butadiene rubber (SBR), nitrile butadiene rubber (NBR), isoprene rubber, polyisobutene, polyethylene glycol (PEO), polymethyl methacrylic acid (PMMA), polyethylene vinyl acetate (PEVA), and the like.

[0054] Polymer particles may be used as polymer compounds that can be dispersed in a liquid. The maximum particle size of the polymer particles should be smaller than the nozzle diameter of the liquid dispensing head. The mode diameter of the polymer particles is preferably 0.01 to 1 μm. Examples of materials constituting the polymer particles include thermoplastic resins such as polyvinylidene fluoride, acrylic resin, styrene-butadiene rubber, polyethylene, polypropylene, polyurethane, nylon, polytetrafluoroethylene, polyphenylene sulfide, polyethylene tephthalate, and polybutylene tephthalate.

[0055] -Active material- As the active material, a positive electrode active material or a negative electrode active material that can be applied to an electrochemical element can be used.

[0056] The positive electrode active material is not particularly limited as long as it is capable of reversibly intercalating and releasing alkali metal ions, but alkali metal-containing transition metal compounds can be used.

[0057] Examples of alkali metal-containing transition metal compounds include lithium-containing transition metal compounds such as composite oxides containing lithium and one or more elements selected from the group consisting of cobalt, manganese, nickel, chromium, iron, and vanadium.

[0058] Examples of the lithium-containing transition metal compounds include lithium cobaltate, lithium nickelate, lithium manganeseate, and lithium nickel-cobalt-manganate.

[0059] As the alkali metal-containing transition metal compound, polyanionic compounds having an XO4 tetrahedron (X=P,S,As,Mo,W,Si, etc.) in their crystal structure can also be used. Among these, lithium-containing transition metal phosphate compounds such as lithium iron phosphate and lithium vanadium phosphate are preferred in terms of cycle characteristics, and lithium vanadium phosphate is particularly preferred in terms of lithium diffusion coefficient and input / output characteristics of the electrochemical element.

[0060] Furthermore, in terms of electronic conductivity, it is preferable that the polyanionic compound is composited with a conductive additive such as a carbon material on its surface.

[0061] The negative electrode active material is not particularly limited as long as it is capable of reversibly intercalating and releasing alkali metal ions, but a carbon material containing graphite having a graphite-type crystal structure can be used.

[0062] Examples of the aforementioned carbon materials include natural graphite, artificial graphite, hard carbon (difficult to graphitize), and soft carbon (easily graphitizable).

[0063] Examples of negative electrode active materials other than the carbon material include lithium titanate and titanium oxide.

[0064] Furthermore, from the viewpoint of the energy density of the electrochemical element, it is preferable to use high-capacity materials such as metallic lithium, silicon, tin, silicon alloys, tin alloys, silicon oxide, silicon nitride, and tin oxide as the negative electrode active material.

[0065] There are no particular restrictions on the content of the active material in the liquid composition, and it can be appropriately selected depending on the purpose, but it is preferably 10% by mass or more, and more preferably 15% by mass or more. When the content of the active material in the liquid composition is 10% by mass or more, the number of printings required to form an electrode composite layer of a predetermined basis weight is reduced.

[0066] -Conductive additive- There are no particular restrictions on the conductive additive, and it can be appropriately selected depending on the purpose. For example, carbon materials such as conductive carbon black, carbon nanofibers, carbon nanotubes, graphene, and graphite particles can be used. Here, the conductive additive may be compounded with the active material.

[0067] Conductive carbon black can be manufactured by methods such as the furnace process, the acetylene process, or the gasification process.

[0068] Other conductive additives besides carbon materials include, for example, metal particles such as aluminum or metal fibers.

[0069] There are no particular restrictions on the amount of conductive additive relative to the active material, and it can be appropriately selected depending on the purpose, but it is preferably 10% by mass or less, and more preferably 8% by mass or less.

[0070] [viscosity] The viscosity of the liquid composition in the first and second embodiments is not particularly limited as long as it does not impair the effects of the present invention, and can be appropriately selected according to the purpose, but it is preferable that the viscosity is such that it can be ejected from the nozzle of an inkjet head. More specifically, the viscosity at 25°C is preferably 200 mPa·s or less, more preferably 100 mPa·s or less, even more preferably 50 mPa·s or less, and particularly preferably 25 mPa·s or less. The lower limit is not particularly limited, but can be appropriately set to a viscosity that can be ejected by an inkjet method.

[0071] There are no particular limitations on the method for measuring the viscosity of the liquid composition, and it can be appropriately selected depending on the purpose. For example, it can be measured by attaching the rotor No. CPA-40Z to a Type B viscometer (cone plate viscometer). In this specification, the viscosity of the liquid composition refers to the viscosity at 25°C.

[0072] [Maximum particle size] The maximum particle size of the solids contained in the liquid composition of the first and second embodiments is not particularly limited as long as it does not impair the effects of the present invention, and can be appropriately selected according to the purpose. However, it is preferable that it is smaller than the nozzle diameter of the inkjet head, and it is preferable that it is sufficiently smaller than the nozzle diameter of the inkjet head in order to further improve inkjet ejection performance. Specifically, the ratio of the maximum particle size of the solids contained in the liquid composition to the nozzle diameter of the inkjet head (maximum particle size of solids contained in the liquid composition / nozzle diameter of the inkjet head) is preferably 0.8 or less, more preferably 0.6 or less, and even more preferably 0.5 or less. That is, if the nozzle diameter of the inkjet head is 40 μm, the maximum particle size of the solids contained in the liquid composition is preferably 32 μm or less, more preferably 24 μm or less, and even more preferably 20 μm or less.

[0073] There are no particular restrictions on the method for measuring the maximum particle size of the solid content contained in the liquid composition, and it can be appropriately selected depending on the purpose. For example, it can be measured in accordance with ISO 13320. There are no particular restrictions on the apparatus used for the measurement, and it can be appropriately selected depending on the purpose. For example, a laser diffraction / scattering particle size distribution analyzer (LA-960, manufactured by Horiba, Ltd.) can be used.

[0074] Furthermore, there are no particular restrictions on the method for measuring the maximum particle size of the powder components used as raw materials for the liquid composition, and it can be appropriately selected depending on the purpose. For example, methods such as measuring using laser diffraction, similar to the method for measuring the maximum particle size of the solid components contained in the liquid composition described above, or determining it from an image obtained by scanning electron diffraction can be used.

[0075] There are no particular limitations on the method for producing the liquid composition, and it can be appropriately selected depending on the purpose. For example, it can be prepared by adding the inorganic solid electrolyte, the dispersant, and other components as needed to the solvent and mixing them. The means of mixing are not particularly limited and can be appropriately selected depending on the purpose, for example, an ultrasonic homogenizer. The conditions for mixing are not particularly limited and can be appropriately selected depending on the purpose.

[0076] There are no particular restrictions on the use of the liquid composition, and it can be appropriately selected according to the purpose, but it can be suitably used as a material for the solid electrolyte layer of an all-solid-state secondary battery or as part of the material when forming the electrode composite layer.

[0077] (container) The container of the present invention is a container that contains the liquid composition of the present invention as described above. There are no particular restrictions on the shape, structure, and size of the aforementioned containment container, and they can be appropriately selected according to the purpose.

[0078] (Equipment for manufacturing solid electrolyte layer or electrode composite layer, method for manufacturing solid electrolyte layer or electrode composite layer) The apparatus for manufacturing a solid electrolyte layer or electrode composite layer of the present invention includes the above-described containment container of the present invention and an ejection means for ejecting the liquid composition contained in the containment container using an inkjet head, and optionally includes other components. The method for manufacturing a solid electrolyte layer or electrode composite layer of the present invention includes an ejection step of ejecting the liquid composition of the present invention described above using an inkjet head, and optionally includes other steps.

[0079] <Discharge means, discharge process> The ejection means is a means for ejecting the liquid composition contained in the container using an inkjet head. The aforementioned ejection step is a step of ejecting the liquid composition using an inkjet head. The aforementioned discharge allows a liquid composition to be applied to an object, thereby forming a liquid composition layer. The aforementioned object (hereinafter sometimes referred to as the "discharge object") is not particularly limited as long as it is an object that forms a solid electrolyte layer or an electrode composite layer, and can be appropriately selected according to the purpose, for example, an active material layer.

[0080] <Other components, other processes> Other components in the apparatus for manufacturing the solid electrolyte layer or electrode composite layer are not particularly limited as long as they do not impair the effects of the present invention, and can be appropriately selected according to the purpose, for example, a heating means. Other steps in the method for manufacturing the solid electrolyte layer or electrode composite layer are not particularly limited as long as they do not impair the effects of the present invention, and can be appropriately selected depending on the purpose. For example, a heating step can be mentioned.

[0081] -Heating means, heating process- The heating means is a means for heating the liquid composition discharged by the discharge means. The heating step is a step of heating the liquid composition discharged in the discharge step. The aforementioned heating allows the liquid composition layer to be dried.

[0082] Figure 1 is a schematic diagram showing an example of a manufacturing apparatus for a solid electrolyte layer or electrode composite layer to realize the manufacturing method of the solid electrolyte layer or electrode composite layer of this embodiment.

[0083] The solid electrolyte layer or electrode composite layer manufacturing apparatus shown in Figure 1 is an apparatus for manufacturing a solid electrolyte layer or electrode composite layer using the liquid composition described above. The solid electrolyte layer or electrode composite layer apparatus includes an extrusion process section 10 which includes a step of applying the liquid composition to a printing substrate 4 having an object to be extruded to form a liquid composition layer, and a heating process section 30 which includes a heating step of heating the liquid composition layer to obtain a solid electrolyte layer or electrode composite layer. The solid electrolyte layer or electrode composite layer apparatus includes a transport section 5 for transporting the printing substrate 4, and the transport section 5 transports the printing substrate 4 in the order of the extrusion process section 10 and the heating process section 30 at a preset speed. There are no particular limitations on the method for manufacturing the printing substrate 4 having the extrusion target material such as the active material layer, and known methods can be appropriately selected.

[0084] The discharge process unit 10 includes an arbitrary printing apparatus 1a corresponding to the inkjet printing method, which is an application means for applying a liquid composition onto a printing substrate 4; a storage container 1b for containing the liquid composition; and a supply tube 1c for supplying the liquid composition stored in the storage container 1b to the printing apparatus 1a.

[0085] The containment container 1b contains the liquid composition 7, and the dispensing process unit 10 dispenses the liquid composition 7 from the printing device 1a to apply the liquid composition 7 onto the printing substrate 4, forming a thin film layer of the liquid composition. The containment container 1b may be integrated with the solid electrolyte layer or electrode composite layer device, or it may be detachable from the solid electrolyte layer or electrode composite layer device. It may also be a container used for adding to a containment container integrated with the solid electrolyte layer or electrode composite layer device, or a containment container detachable from the solid electrolyte layer or electrode composite layer device.

[0086] The containment container 1b and supply tube 1c can be arbitrarily selected as long as they are capable of stably storing and supplying the liquid composition 7.

[0087] As shown in Figure 1, the heating process section 30 includes a heating device 3a and includes a solvent removal step in which the solvent remaining in the liquid composition layer is heated and dried by the heating device 3a to remove it. This allows for the formation of a solid electrolyte layer or an electrode composite layer. The heating process section 30 may perform the solvent removal step under reduced pressure.

[0088] There are no particular restrictions on the heating device 3a, and it can be appropriately selected according to the purpose. Examples include substrate heating, IR heaters, and hot air heaters, and these may be combined.

[0089] Furthermore, the heating temperature and time can be appropriately selected depending on the boiling point of the solvent contained in the liquid composition 7 and the film thickness to be formed.

[0090] Figure 2 is a schematic diagram showing another example of a manufacturing apparatus (liquid dispensing apparatus) for a solid electrolyte layer or electrode composite layer to realize the manufacturing method of the solid electrolyte layer or electrode composite layer of this embodiment.

[0091] The liquid dispensing device 300' controls the pump 310 and valves 311 and 312, enabling the liquid composition to circulate through the liquid dispensing head 306, tank 307, and tube 308.

[0092] Furthermore, the liquid discharge device 300' is equipped with an external tank 313, and when the liquid composition in tank 307 decreases, it is possible to supply the liquid composition from the external tank 313 to tank 307 by controlling the pump 310 and valves 311, 312, and 314.

[0093] By using a manufacturing apparatus for a solid electrolyte layer or electrode composite layer, the liquid composition can be discharged to a targeted location on the object to be discharged.

[0094] The solid electrolyte layer or electrode composite layer can be suitably used, for example, as part of the configuration of an energy storage element. There are no particular restrictions on the components of the energy storage element other than the solid electrolyte layer or electrode composite layer, and known components can be appropriately selected, such as a positive electrode, a negative electrode, a separator, etc.

[0095] As for the manufacturing method of the energy storage element, a known method can be appropriately selected, except that the solid electrolyte layer or electrode composite layer is the present invention.

[0096] There are no particular restrictions on the shape of the energy storage element, and it can be appropriately selected according to the purpose. For example, in addition to the shape shown in Figure 3, various shapes that are commonly used can be appropriately selected according to the application. There are no particular restrictions on the shape, and it can be appropriately selected according to the purpose. For example, examples include a cylinder type in which the sheet electrode and solid electrolyte layer are arranged in a spiral shape, a cylinder type with an inside-out structure combining a pellet electrode and a solid electrolyte layer, and a coin type in which the pellet electrode and solid electrolyte layer are stacked.

[0097] Figure 3 is a schematic diagram showing an example of an energy storage element provided with a solid electrolyte layer according to this embodiment. As shown in Figure 3, the energy storage element 110 according to this embodiment includes a positive electrode 11, a negative electrode 12 provided opposite the positive electrode 11, and a solid electrolyte layer 13 disposed between the positive electrode 11 and the negative electrode 12. The energy storage element 110 includes a container 15 that serves as an outer casing and encloses and holds a positive electrode 11, a negative electrode 12, and an electrolyte layer 13, a positive electrode wire 16 that passes through the container 15 and is connected to the positive electrode 11, and a negative electrode wire 17 that similarly passes through the container 15 and is connected to the negative electrode 12.

[0098] <Application> There are no particular restrictions on the use of the aforementioned energy storage element, and it can be used for a variety of purposes. Examples include power supplies and backup power supplies for laptop computers, pen-input computers, mobile computers, e-book players, mobile phones, portable fax machines, portable copiers, portable printers, headphone stereos, video cameras, LCD televisions, handheld vacuum cleaners, portable CDs, MiniDiscs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, motors, lighting fixtures, toys, game consoles, clocks, strobes, cameras, vehicles, etc. [Examples]

[0099] The present invention will be described in more detail below based on the examples. However, the present invention is not limited to the examples. Unless otherwise specified, the following operations were performed in an argon glove box maintained at a dew point of -70°C or below to suppress the reaction between the inorganic solid electrolyte and moisture in the atmosphere.

[0100] (Preparation Example 1: Synthesis of Inorganic Solid Electrolyte 1) As inorganic solid electrolyte 1, the argyrodite-type sulfide solid electrolyte Li6PS5Cl(LPSC) was synthesized according to reference 1 (Nataly Carolina Rosero-Navarro et al., Journal of Power Sources 396(2018)33).

[0101] (Preparation Example 2: Synthesis of Inorganic Solid Electrolyte 2) As inorganic solid electrolyte 2, Li 10 GeP2S 12 (LGPS) was synthesized according to reference 2 (J.Mater.Chem.A3, 438-446 (2015)).

[0102] (Examples 1-11 and Comparative Examples 1-8: Preparation of Liquid Compositions) In Examples 1-11 and Comparative Examples 1-8 described below, an inorganic solid electrolyte and a dispersant were added to a dehydrated solvent, and the mixture was obtained by mixing for 10 minutes at 70% output using an ultrasonic homogenizer (US-300E) manufactured by Nippon Seiki Seisakusho Co., Ltd. Here, the dehydrated solvent used was one whose water content was confirmed to be 100 ppm or less using a Karl Fischer moisture meter.

[0103] [evaluation] The vapor pressures at 25°C of the solvents used in Examples 1 to 11 and Comparative Examples 1 to 8 below were determined as follows. Furthermore, the liquid compositions of Examples 1 to 11 and Comparative Examples 1 to 8 were evaluated for hydrogen sulfide detection, inkjet ejection performance, and re-ejection performance after stopping, as follows.

[0104] [Vapor pressure at 25°C] For the vapor pressure of each solvent, the values ​​listed in the Safety Data Sheet (SDS) for each solvent were referred to. For those not listed in the SDS, the values ​​were measured according to the isotenoscope method described in Reference 3 (Research on Understanding the Physicochemical Properties of Chemical Substances (1986 / Published by the Japan Environmental Association / Authored by the Health Investigation Office, Environmental Health Department, Environment Agency)).

[0105] [Detection of hydrogen sulfide] The determination of whether hydrogen sulfide was generated from the mixed liquid composition was made as follows. Ten mL of the liquid composition was placed in a screw-cap tube and stored in an argon glove box at 25°C for one hour. After storage, a hydrogen sulfide sensor (Honeywell BW Solo lite) was brought close to the tube. When the screw-cap tube was opened, if the hydrogen sulfide sensor displayed a value of 0.1 ppm or higher for three seconds or more, it was determined that hydrogen sulfide had been generated. For safety reasons, inkjet ejection performance and re-ejection performance after stopping were not evaluated for those evaluated as "b" in this test. -evaluation- a: No hydrogen sulfide generation b: Hydrogen sulfide is being generated.

[0106] [Inkjet ejection properties] The inkjet ejection properties of liquid compositions were evaluated as follows using the EV1000 droplet observation device (manufactured by Ricoh Co., Ltd.). The liquid composition to be evaluated was ejected from one nozzle (nozzle diameter: 40 μm) of the inkjet head using the EV1000. If the ejection state could be maintained for 60 seconds or more, it was determined to be ejectable. Maintaining the ejection state for 60 seconds or more means that the liquid composition is being ejected at least 60 seconds after the start of ejection, and the amount ejected is not a factor. In other words, as long as the liquid composition is being ejected at least 60 seconds after the start of ejection, the amount ejected may or may not change between the start of ejection and 60 seconds after the start of ejection. Due to the nature of the test for re-dispensing after stopping, re-dispensing after stopping was not evaluated for those evaluated as "×" in this test. -evaluation- ○: Discharge possible (can maintain discharge state for 60 seconds or more). ×: Not capable of dispensing (cannot maintain dispensing state for 60 seconds).

[0107] [Re-dischargeability after stopping] The re-ejectability of liquid compositions after inkjet ejection was evaluated as follows using the EV1000 droplet observation device (manufactured by Ricoh Co., Ltd.). The liquid composition to be evaluated was ejected from one nozzle (nozzle diameter: 40 μm) of the inkjet head using the EV1000. After maintaining the ejection state for 60 seconds, it was allowed to stand for 5 minutes. If it could be ejected again without problems after that, it was determined that it was possible to stop and re-eject. -evaluation- ○: Can be re-discharged ×: Not re-dispensable

[0108] <Example 1> 40 g of undecane (manufactured by Tokyo Chemical Industry Co., Ltd.) was taken as a solvent, and 56 g of the inorganic solid electrolyte 1 and 4 g of a dispersant (SOLSPERSE3000 manufactured by Lubrizol (hereinafter sometimes referred to as "S-3000")) were added to it. The mixture was then mixed using an ultrasonic homogenizer to obtain the liquid composition of Example 1.

[0109] <Example 2> A liquid composition was prepared in the same manner as in Example 1, except that tetradecane (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was the liquid composition of Example 2.

[0110] <Example 3> A liquid composition was prepared in the same manner as in Example 1, except that 2-butyloctane (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was the liquid composition of Example 3.

[0111] <Example 4> A liquid composition was prepared in the same manner as in Example 1, except that butylphenyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was the liquid composition of Example 4.

[0112] <Example 5> A liquid composition was prepared in the same manner as in Example 1, except that dihexyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was the liquid composition of Example 5.

[0113] <Example 6> A liquid composition was prepared in the same manner as in Example 1, except that 2-nonyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was the liquid composition of Example 6.

[0114] <Example 7> A liquid composition was prepared in the same manner as in Example 1, except that 2-ethylhexyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was the liquid composition of Example 7.

[0115] <Example 8> A liquid composition was prepared in the same manner as in Example 1, except that 2-ethylhexyl propionate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was the liquid composition of Example 8.

[0116] <Example 9> A liquid composition was prepared in the same manner as in Example 1, except that Marialim SC-0708A (manufactured by Nippon Oil & Fats Co., Ltd., hereinafter sometimes referred to as "SC0708A") was used as a dispersant instead of S-3000, and this became the liquid composition of Example 9.

[0117] <Example 10> A liquid composition was prepared in the same manner as in Example 1, except that inorganic solid electrolyte 2 was used instead of inorganic solid electrolyte 1 as the inorganic solid electrolyte, and this became the liquid composition of Example 10.

[0118] <Example 11> A liquid composition was prepared in the same manner as in Example 1, except that a mixture of tetradecane and 2-ethylhexyl acetate in a mass ratio of 1:1 was used as the solvent instead of undecane, and this was the liquid composition of Example 11.

[0119] <Comparative Example 1> A liquid composition was prepared in the same manner as in Example 1, except that n-decane (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was obtained as the liquid composition of Comparative Example 1.

[0120] <Comparative Example 2> A liquid composition was prepared in the same manner as in Example 1, except that n-pentadecane (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was obtained as the liquid composition of Comparative Example 2.

[0121] <Comparative Example 3> A liquid composition was prepared in the same manner as in Example 1, except that propoxybenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was obtained as the liquid composition of Comparative Example 3.

[0122] <Comparative Example 4> A liquid composition was prepared in the same manner as in Example 1, except that diheptyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was obtained as the liquid composition of Comparative Example 4.

[0123] <Comparative Example 5> A liquid composition was prepared in the same manner as in Example 1, except that 1,4-diethoxybenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was obtained as the liquid composition of Comparative Example 5.

[0124] <Comparative Example 6> A liquid composition was prepared in the same manner as in Example 1, except that n-octyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was obtained as the liquid composition of Comparative Example 6.

[0125] <Comparative Example 7> A liquid composition was prepared in the same manner as in Example 1, except that 2-ethylhexyl butyrate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the solvent instead of undecane, and this was obtained as the liquid composition of Comparative Example 7.

[0126] <Comparative Example 8> A liquid composition was prepared in the same manner as in Example 1, except that a dispersant was not used, and this was the liquid composition of Comparative Example 8.

[0127] The evaluation results of the above-mentioned examples and comparative examples are shown in Table 1 below. In Table 1, under the "Presence or Absence of Hydrogen Sulfide Generation" column, "a" indicates "No hydrogen sulfide generation" and "b" indicates "Hydrogen sulfide generation present."

[0128] [Table 1]

[0129] From the results of Examples 1, 2, and 3, and Comparative Examples 1 and 2, among solvents having an aliphatic hydrocarbon structure, undecane (Example 1) and tetradecane (Example 2), which have a vapor pressure of 0.1 hPa to 1.0 hPa, showed no detection of hydrogen sulfide, good inkjet ejection performance, and good re-ejection performance after stopping. In contrast, n-decane (Comparative Example 1), which has a vapor pressure greater than 1.0 hPa, dried quickly at the inkjet nozzle, causing clogging during re-ejection after stopping. Furthermore, n-pentadecane (Comparative Example 2), which has a vapor pressure less than 0.1 hPa, had high solvent viscosity, and the viscosity of the prepared liquid composition was also high, resulting in clogging during the evaluation of inkjet ejection performance. From this, it can be concluded that solvents having an aliphatic hydrocarbon structure with a vapor pressure of 0.1 hPa to 1.0 hPa are preferable. In addition, 2-butyloctane (Example 3) also showed good evaluation results in all cases, indicating that similar effects can be obtained even with branched aliphatic hydrocarbons.

[0130] The results from Examples 4 and 5, and Comparative Examples 3, 4, and 5, show that among solvents having an ether structure, butylphenyl ether (Example 4) and dihexyl ether (Example 5), with vapor pressures of 0.1 hPa to 1.0 hPa, showed no detection of hydrogen sulfide, good inkjet ejection performance, and good re-ejection performance after stopping. In contrast, propoxybenzene (Comparative Example 3), with a vapor pressure greater than 1.0 hPa, dried quickly at the inkjet nozzle, causing clogging during re-ejection after stopping. Diheptyl ether (Comparative Example 4), with a vapor pressure less than 0.1 hPa, had high solvent viscosity, and the viscosity of the prepared liquid composition was also high, resulting in clogging during evaluation of inkjet ejection performance. Therefore, even for solvents having an ether structure, it is necessary for the vapor pressure to be between 0.1 hPa and 1.0 hPa. Furthermore, hydrogen sulfide was detected in the liquid composition of 1,4-diethoxybenzene (Comparative Example 5), which has a diether structure. This indicates that structures containing multiple ether groups are unsuitable for use because they are highly reactive with sulfide solid electrolytes.

[0131] Examples 6, 7, and 8, and Comparative Examples 6 and 7, show that among solvents having an ester structure, 2-nonyl acetate (Example 6), which has a branch at position 1 from the carbon bonded to the oxygen side of the ester group, and 2-ethylhexyl acetate (Example 7), which has a branch at position 2, both had no detectable hydrogen sulfide, exhibited good inkjet ejection performance, and also showed good re-ejection performance after stopping. In contrast, hydrogen sulfide was detected in the liquid composition of n-octyl acetate (Comparative Example 6), which does not have a branch at the carbon bonded to the oxygen side of the ester group. From this, it can be seen that esters without a branch at the carbon bonded to the oxygen side are unsuitable for use because they have high reactivity with sulfide solid electrolytes. Furthermore, while 2-ethylhexyl butyrate (Comparative Example 7), in which a propyl group is bonded to the carbon side of the ester group, suppresses the generation of hydrogen sulfide, its vapor pressure is less than 0.1 hPa, resulting in a high viscosity of the liquid composition and causing clogging during inkjet ejection, 2-ethylhexyl propionate (Example 8), in which an ethyl group is bonded to the carbon side of the ester group, has a vapor pressure within the range of 0.1 hPa to 1.0 hPa, and no clogging occurred during inkjet ejection. From this, it was found that for solvents having an ester structure, a vapor pressure of 0.1 hPa to 1.0 hPa is preferable, and a methyl group or an ethyl group is preferable as the group bonded to the carbon side of the ester group.

[0132] From Example 9 and Comparative Example 8, Comparative Example 8, in which no dispersant was added, resulted in particle aggregation and clogging during inkjet ejection. On the other hand, Example 9, in which the type of dispersant was changed from Example 1, showed ejection performance as good as Example 1. From this, it was found that the addition of a dispersant is essential, but the effects of the present invention can be obtained regardless of the type of dispersant, as long as an effective dispersant is used.

[0133] From Example 10, it was found that Example 10, in which the type of inorganic solid electrolyte was changed from Example 1, showed dispensing performance as good as that of Example 1. From this, it was found that the effects of the present invention can be obtained regardless of the type of solid electrolyte.

[0134] From Example 11, it was found that Example 11, which used a mixed solvent, showed dispensing performance as good as that of Example 1. From this, it was found that the effects of the present invention can be obtained even when a mixed solvent is used.

[0135] Examples of embodiments of this model are as follows: <1> A liquid composition comprising a solvent, an inorganic solid electrolyte, and a dispersant, The solvent is a liquid composition characterized by being at least one selected from the group consisting of (I) aliphatic hydrocarbons, (II) monoethers, and (III) esters having a branched structure, with a vapor pressure of 0.1 hPa or more and 1.0 hPa or less at 25°C. <2> The viscosity of the liquid composition is 200 mPa·s or less. <1> This is the liquid composition described in [the relevant document]. <3> The maximum particle size of the solid content contained in the liquid composition is 32 μm or less. <1> from <2> It is a liquid composition as described in any of the above. <4> A liquid composition ejected using an inkjet head, The liquid composition comprises a solvent, an inorganic solid electrolyte, and a dispersant. The solvent is a liquid composition characterized by being at least one selected from the group consisting of (I) aliphatic hydrocarbons, (II) monoethers, and (III) esters having a branched structure, with a vapor pressure of 0.1 hPa or more and 1.0 hPa or less at 25°C. <5> The viscosity of the liquid composition is such that it can be ejected from the nozzle of the inkjet head. <4> This is the liquid composition described in [the relevant document]. <6> The maximum particle size of the solids contained in the liquid composition is smaller than the nozzle diameter of the inkjet head. <4> from <5> It is a liquid composition as described in any of the above. <7> The ratio of the maximum particle size of the solid content contained in the liquid composition to the nozzle diameter of the inkjet head is 0.8 or less. <4> from <6> It is a liquid composition as described in any of the above. <8> The aliphatic hydrocarbon (I) is an aliphatic hydrocarbon having 11 to 14 carbon atoms. <1> from <7> It is a liquid composition as described in any of the above. <9> The (II) monoether is a monoether having 11 to 13 molecules that constitute the basic skeleton. <1> from <8> It is a liquid composition as described in any of the above. <10> The (III) ester having a branched structure is an ester of either (i) an ester in which a hydrocarbon group having 2 or fewer carbon atoms is bonded to the carbon side of the ester group and a hydrocarbon group having a branched structure is bonded to the oxygen side of the ester group, or (ii) an ester in which a hydrocarbon group having 3 or fewer carbon atoms is bonded to the oxygen side of the ester group and a hydrocarbon group having a branched structure is bonded to the carbon side of the ester group. <1> from <9> It is a liquid composition as described in any of the above. <11> The solvent is used by mixing one or more solvents having a structure selected from the group consisting of (I), (II), and (III). <1> from <10> It is a liquid composition as described in any of the above. <12> The aforementioned <1> from <11> A container characterized by containing a liquid composition as described in any of the above. <13> The aforementioned <12> The apparatus for manufacturing a solid electrolyte layer or electrode composite layer is characterized by comprising a containment container described above and a dispensing means for dispensing the liquid composition contained in the containment container using an inkjet head. <14> Using the inkjet head <1> from <11> A method for producing a solid electrolyte layer or electrode composite layer, characterized by including a dispensing step of dispensing the liquid composition described in any of the above.

[0136] The aforementioned <1> from <11> A liquid composition according to any of the above, <12> The container described above, <13> A manufacturing apparatus for a solid electrolyte layer or electrode composite layer as described above, or the same <14> The method for manufacturing a solid electrolyte layer or electrode composite layer described herein can solve the problems of the past and achieve the objectives of the present invention. [Explanation of symbols]

[0137] 1a Printing device 1b Containment container 1c Supply tube 3a Heating device 4 Printing base material 5. Conveying section 7 Liquid composition 10 Discharge process section 11 Positive electrode 12 Negative electrode 13 Solid electrolyte layer 15 Container 16 Positive electrode wire 17 Negative electrode wire 30 Heating process section 110 Energy storage element 300' liquid dispensing device 306 Liquid Dispensing Head 307 Tank 308 Tube 310 pump 311 Valve 312 Valve 313 External Tank 314 Valve [Prior art documents] [Patent Documents]

[0138] [Patent Document 1] International Publication No. 2016 / 013224 [Patent Document 2] International Publication No. 2019 / 054455 [Patent Document 3] Japanese Patent Publication No. 2009-211950 [Patent Document 4] Japanese Patent Publication No. 2009-211950

Claims

1. A liquid composition ejected using an inkjet head, The liquid composition comprises a solvent, an inorganic solid electrolyte, and a dispersant. The solvent is characterized by being at least one selected from the group consisting of (I) aliphatic hydrocarbons, (II) monoethers, and (III) esters having a branched structure, having a vapor pressure of 0.1 hPa or more and 1.0 hPa or less at 25°C.

2. The liquid composition according to claim 1, wherein the viscosity of the liquid composition at 25°C is 200 mPa·s or less.

3. The liquid composition according to claim 1, wherein the viscosity of the liquid composition is such that it can be dispensed from the nozzle of an inkjet head.

4. The liquid composition according to any one of claims 1 to 3, wherein the maximum particle size of the solid content contained in the liquid composition is 32 μm or less.

5. The liquid composition according to any one of claims 1 to 3, wherein the maximum particle size of the solid content contained in the liquid composition is smaller than the nozzle diameter of the inkjet head.

6. The liquid composition according to any one of claims 1 to 5, wherein the ratio of the maximum particle size of the solid content contained in the liquid composition to the nozzle diameter of the inkjet head is 0.8 or less.

7. The liquid composition according to any one of claims 1 to 6, wherein the (I) aliphatic hydrocarbon is an aliphatic hydrocarbon having 11 to 14 carbon atoms.

8. The liquid composition according to any one of claims 1 to 7, wherein the (II) monoether is a monoether having 11 to 13 molecules constituting the basic skeleton.

9. The liquid composition according to any one of claims 1 to 8, wherein the (III) ester having a branched structure is an ester of either (i) an ester in which a hydrocarbon group having 2 or fewer carbon atoms is bonded to the carbon side of the ester group and a hydrocarbon group having a branched structure is bonded to the oxygen side of the ester group, or (ii) an ester in which a hydrocarbon group having 3 or fewer carbon atoms is bonded to the oxygen side of the ester group and a hydrocarbon group having a branched structure is bonded to the carbon side of the ester group.

10. The liquid composition according to any one of claims 1 to 9, wherein the solvent is a mixture of one or more solvents having a structure selected from the group consisting of (I), (II), and (III).

11. A container characterized by containing the liquid composition according to any one of claims 1 to 10.

12. A manufacturing apparatus for a solid electrolyte layer or electrode composite layer, comprising a container according to claim 11 and a dispensing means for dispensing the liquid composition contained in the container using an inkjet head.

13. A method for manufacturing a solid electrolyte layer or electrode composite layer, characterized by comprising a dispensing step of dispensing the liquid composition described in any one of claims 1 to 10 using an inkjet head.

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