ADHESIVE

Abstract

This adhesive agent is a phosphorus-containing molten salt solution that is used in order to join powder materials together, or to join a powder material and a thin film material. The adhesive agent satisfies the following: (1) containing an ion conductive species and a phosphorus-containing compound which is an ion conductor precursor; (2) containing a phosphorus-containing molten salt as an ion conductor precursor, the phosphorus-containing molten salt being a salt of an ion conductive species of phosphoric acid; or (3) containing a phosphorus-containing molten salt as an ion conductor precursor, and having an ion conductive species on the surface of the powder material.

Description

glue

[0001] The present invention relates to adhesives.

[0002] When manufacturing a bonded body of powder materials, impurity phases formed on the surface of the powder materials may hinder bonding.

[0003] For example, when the powder material is a lithium ion conductor, the presence of lithium carbonate, lithium hydroxide, etc. on the powder material surface can inhibit ion conduction and reduce sinterability, making it difficult to manufacture a bonded body between powder materials or a bonded body between a powder material and a thin film material, and resulting in reduced performance. On the other hand, when sintering is performed at high temperatures to remove such impurity phases, element diffusion occurs at the bonded interface between the powder materials or between the powder material and a thin film material, resulting in the formation of an impurity phase. For this reason, technological development is required to treat the surface of the powder material and to bond it at low temperatures.

[0004] The present invention is intended to solve the above-mentioned problems, and has an object to provide a method that can bond powder materials together or a powder material and a thin film material at low temperatures.

[0005] The present inventors conducted extensive research to solve the above-mentioned problems. The present inventors discovered that a phosphorus molten salt, which is an ion conductor precursor, reacts with phosphorus in solution and ion-conducting species to form a solid or gel ion conductor, which then penetrates into the surface or pores of the matrix, thereby promoting bonding between solid materials via the phosphate ion conductor at low temperatures. Furthermore, they discovered that a phosphate ion conductor (gel-like) can react and hydrolyze with moisture in the air or in response to added moisture, forming a phosphate ion conductor (crystalline) or a non-ion conductor at the interface with the moisture, thereby bonding solid materials. The present invention was completed based on the above findings and through further extensive research, and includes the following features.

[0006] Item 1. An adhesive used to bond powder materials together or the powder material and a thin film material, which satisfies the following: (1) contains a phosphorus-containing molten salt that is an ion conductor precursor and an ion-conducting species; (2) contains a phosphorus-containing molten salt that is an ion conductor precursor, and the phosphorus-containing molten salt is a salt of an ion-conducting species of phosphoric acid; or (3) contains a phosphorus-containing molten salt that is an ion conductor precursor, and has an ion-conducting species on the surface of the powder material.

[0007] Item 2. The adhesive according to Item 1, wherein the powder material is at least one material selected from the group consisting of an ion conductor, an electrode active material, a metal material, an organic material, a glass material, and a ceramic material.

[0008] Item 3. The adhesive according to Item 1 or 2, which is a liquid, gel, or solid.

[0009] Item 4. The adhesive according to any one of Items 1 to 3, wherein the phosphorus-containing molten salt is at least one selected from the group consisting of phosphoric acid, hydrogen phosphate, condensed phosphoric acid, and organic phosphoric acid compounds.

[0010] Item 5. The adhesive according to any one of Items 1 to 4, wherein the ion-conducting species contains at least one ion selected from the group consisting of alkali metal ions and alkaline earth metal ions.

[0011] Item 6. The adhesive according to any one of Items 1 to 5, which satisfies (1) above and is a mixture of the mixture of the phosphorus-containing molten salt and the ion-conducting species, and a solvent.

[0012] Item 7. A method for producing a bonded body of powder materials or a bonded body of the powder material and a thin film material, the method comprising: (1) a step of bringing the powder material, or the powder material and the thin film material, into contact with the adhesive according to any one of Items 1 to 6.

[0013] Item 8. The production method according to Item 7, wherein in the step (1), a pressure treatment is carried out after the contact.

[0014] Item 9. The manufacturing method according to Item 7 or 8, further comprising: (2) a step of heating after the step (1).

[0015] Item 10. The method according to Item 9, wherein the heating temperature in step (2) is 30 to 500°C.

[0016] According to the present invention, it is possible to bond powder materials together or the powder material and thin film material together at low temperatures.

[0017] 1 shows an X-ray diffraction pattern of the phosphorus-containing molten salt obtained in Synthesis Example 1. 2 shows the appearance of the phosphorus-containing molten salt obtained in Synthesis Example 1. 3 shows the viscosity of the phosphorus-containing molten salt obtained in Synthesis Example 1. 4 shows an X-ray diffraction pattern of the lithium and phosphorus-containing molten salt (adhesive) of Example 1. 5 shows a Nyquist plot of the lithium and phosphorus-containing molten salt (adhesive) obtained in Example 2. 6 shows a Nyquist plot of the silicon-added lithium and phosphorus-containing molten salt (adhesive) obtained in Example 3. 7 shows the appearance of the silicon-added lithium and phosphorus-containing molten salt (adhesive) obtained in Example 3. 8 shows the appearance of a solution obtained by adding pure water to the lithium and phosphorus-containing molten salt obtained in Example 4. 9 shows a Nyquist plot of the ionic conductor conjugate pellet produced in Example 4. 10 shows an X-ray diffraction pattern of the ionic conductor conjugate pellet produced in Example 4. 11 shows a cross-sectional scanning electron microscope (SEM) image of the ionic conductor conjugate pellet produced in Example 4. 12 shows an X-ray diffraction pattern of the ionic conductor conjugate pellet produced in Example 5. 1 shows a cross-sectional scanning electron microscope (SEM) image of an ion conductor conjugate pellet produced in Example 5. 2 shows the appearance of an ion conductor conjugate pellet produced in Example 5. 3 shows the results of constant voltage charge / discharge measurements of an all-solid-state battery produced in Example 6. 4 shows the results of Reference Example 1. 5 shows the results of Reference Example 2. 6 shows the results of Reference Example 3. 7 shows a Bode plot and an appearance photograph of an adhesive produced in Example 7. 8 shows a Bode plot and an appearance photograph of an adhesive produced in Example 8 (additive element: Nb, W, Mo, Zr, Ta, or Hf). 9 shows a Bode plot and an appearance photograph of an adhesive produced in Example 8 (additive element: Ni, Ti, V, Cr, Mn, Fe, or Co). 10 shows a Bode plot and an appearance photograph of an adhesive produced in Example 8 (additive element: La or Ce). 11 shows a Bode plot and an appearance photograph of an adhesive produced in Example 9 (additive element: B, Al, Ga, or In). Shown are a Bode diagram and an external photograph of the adhesive (added element: Ge or Si) produced in Example 10. Shown are a Bode diagram and an external photograph of the adhesive (added element: Br, Cl, I or F) produced in Example 11. Shown are external photographs of the adhesives (added element: Cu, Zn or N (ammonium ion)) produced in Examples 12 and 13. Shown are a Bode diagram and an external photograph of the adhesive (added element: Cu or Zn) produced in Example 12. Shown are external photographs of the adhesive (added element: N) produced in Example 13.

[0018] In this specification, the term "comprise" is a concept that encompasses "consist essentially of" and "consist only of."

[0019] In this specification, when a range is expressed as "A to B," it means A or more and B or less, unless otherwise specified.

[0020] 1. Adhesive (First Aspect) An adhesive according to a first aspect of the present invention is an adhesive used to bond powder materials together or to bond the powder material to a thin film material, and contains: (1) a phosphorus-containing molten salt that is an ion conductor precursor and an ion-conducting species.

[0021] The adhesive of the present invention is a material that includes not only liquid but also solid and gel forms. For example, the adhesive of the present invention may exist as an amorphous solid immediately after production, but when left standing in the air, it gradually absorbs moisture from the air and becomes gel-like, and over time it can liquefy.

[0022] (1-1) Phosphorus-Containing Molten Salt The phosphorus-containing molten salt is not particularly limited, but is an ion conductor precursor because it becomes an ion conductor due to the presence of an ion-conducting species, and thus allows bonding between powder materials or between the powder material and a thin film material via the ion conductor at low temperatures.

[0023] This phosphorus-containing molten salt is preferably liquid at room temperature (particularly 25° C.) because it is easy to handle in the air.

[0024] Furthermore, since the phosphorus-containing molten salt becomes an ion conductor due to the presence of ion-conducting species, bonding between powder materials or between the powder material and a thin film material via the phosphorus-containing ion conductor can be performed at low temperatures, the melting temperature of the phosphorus-containing molten salt is preferably close to the heating temperature when the manufacturing method of the present invention described below is employed. For example, when the phosphorus-containing molten salt is ammonium dihydrogen phosphate, it is preferably melted at 170 to 300°C, particularly 190 to 240°C.

[0025] Examples of phosphorus-containing molten salts that are ion conductor precursors include phosphoric acid, hydrogen phosphates (ammonium dihydrogen phosphate, sodium dihydrogen phosphate, potassium dihydrogen phosphate, calcium dihydrogen phosphate, cobalt dihydrogen phosphate, zinc dihydrogen phosphate, ammonium monohydrogen phosphate, sodium monohydrogen phosphate, potassium monohydrogen phosphate, calcium monohydrogen phosphate, cobalt monohydrogen phosphate, zinc monohydrogen phosphate, etc.), condensed phosphoric acids (orthophosphate, pyrophosphate, triphosphate, tetraphosphate, polyphosphate, etc.), and organic phosphoric acid compounds (phosphine oxide, phosphonate ester, phosphate ester, etc.). These phosphorus-containing molten salts can be used alone or in combination of two or more.

[0026] Furthermore, as additive materials to the phosphorus-containing molten salt, for example, metal elements (transition metal elements such as vanadium, chromium, titanium, manganese, iron, cobalt, nickel, copper, zinc, hafnium, lanthanum, etc.; typical metal elements such as aluminum, gallium, indium, etc.), metalloid elements (boron, germanium, silicon, etc.), non-metal elements (nitrogen, fluorine, chlorine, bromine, iodine, sulfur, etc.), and their hydrides, oxides, carbides, carbonates, hydrates, etc. can also be used, and these can be used alone or in combination of two or more. Although not particularly limited, in the case of an inorganic phosphorus-containing molten salt, the content of each metal element is preferably about 0 to 3 mols, and more preferably about 0.1 to 0.5 mols, per mol of phosphorus in the inorganic phosphorus-containing molten salt.

[0027] Furthermore, organic compounds such as amine compounds (methylamine, ethylamine, etc.), carbamide compounds (urea, etc.), guanidine compounds (guanidine, guanidine sulfide, arginine) may be contained. When the organic compound is urea, the amount of urea used may be about 0 to 3 moles, particularly about 0.1 to 0.5 moles, per mole of phosphorus.

[0028] The content of the phosphorus-containing molten salt is not particularly limited, but is preferably 0.05 to 0.99 mol, and more preferably 0.15 to 0.80 mol, relative to 1 mol of the total amount of the phosphorus-containing molten salt and the ion-conducting species.

[0029] (1-2) Ion-conducting species The ion-conducting species is not particularly limited, but preferably contains alkali metal ions (lithium ions, sodium ions, potassium ions, etc.), alkaline earth metal ions (magnesium ions, calcium ions, etc.), etc., because the ion-conducting species react with phosphorus in the solution to generate an ion conductor, which is formed on the surface or in pores of the matrix, and can promote bonding between solid materials via the phosphate ion conductor at low temperatures.

[0030] Specific examples of such ion-conductive species include lithium carbonate, lithium hydroxide, lithium fluoride, lithium chloride, lithium bromide, lithium iodide, sodium carbonate, sodium hydroxide, sodium fluoride, sodium chloride, sodium bromide, sodium iodide, potassium carbonate, potassium hydroxide, potassium fluoride, potassium chloride, potassium bromide, potassium iodide, magnesium carbonate, magnesium hydroxide, magnesium fluoride, magnesium chloride, magnesium bromide, magnesium iodide, calcium carbonate, calcium hydroxide, calcium fluoride, calcium chloride, calcium bromide, calcium iodide, etc. These ion-conductive species can be used alone or in combination of two or more.

[0031] The content of the ion-conductive species is not particularly limited, but is preferably 0.01 to 0.95 mol, and more preferably 0.20 to 0.85 mol, relative to 1 mol of the total amount of the phosphorus-containing molten salt and the ion-conductive species.

[0032] The content of the ion-conducting species is not particularly limited, but is preferably 0 to 3.00 mol, more preferably 0.05 to 2.00 mol, relative to 1 mol of the phosphorus-containing molten salt, and when produced in air, is even more preferably 0.05 to 0.50 mol.

[0033] (1-3) Solvent The solvent that can be used for the adhesive of the present invention is not particularly limited, but because phosphate is generated by hydrolysis, it is preferable not to use water as a solvent when using the adhesive of the present invention as a solution to apply and bond materials. However, water can be used when applying the adhesive of the present invention between materials to generate phosphate and fix them.

[0034] The amount of water contained varies depending on the type of ionic conductor (such as a phosphorus-containing salt) to be produced by hydrolysis, but can be adjusted as appropriate.

[0035] (1-4) Adhesive The adhesive of the present invention, which satisfies the above requirements, can be used to bond powder materials together or powder materials and thin film materials. The adhesive of the present invention reacts with the phosphorus in the phosphorus-containing molten salt and ion-conducting species to produce an ion-conducting solid at low temperatures and a viscous solution or gel upon heating. This solution or gel penetrates into the surface or pores of the parent phase, chemically and physically promoting bonding between solid materials. Therefore, there are no particular limitations on the types of powder materials and thin film materials to be bonded.

[0036] Examples of powder materials that can be used include ion conductors, electrode active materials, metal materials, organic materials, glass materials, wood materials, and ceramic materials. Examples of ion conductors that can be used include phosphorus-containing ion conductors (oxide solid electrolyte LiTa ２ P.O. ８ , Li ３ P.O. ４ etc; sulfide solid electrolyte Li １０ GeP ２ S １２ Examples of electrode active materials that can be used include LiCoO ２ , LiTiO ２ , LiFePO ４ , LiCoPO ４ , LiFeMnO ４ , Li ２ MnO ３ , LiMn ２ O ４Examples of usable metal materials include aluminum, stainless steel, and nickel. Examples of usable organic materials include polyethylene and polypropylene. Examples of usable glass materials include soda-lime glass, borosilicate glass, and phosphate glass. Examples of usable wood materials include pulp. Examples of usable ceramic materials include alumina, zirconia, and silicon carbide. These powder materials can be used alone or in combination of two or more.

[0037] Usable thin film materials include, for example, aluminum foil, copper foil, nickel foil, iron foil, etc. These thin film materials can be used alone or in combination of two or more.

[0038] In the adhesive of the present invention, if the phosphorus-containing molten salt is dissolved in a large amount of water before mixing the phosphorus-containing molten salt and the ion-conductive species, the phosphorus-containing molten salt contained in the large amount of water will react first with the ion-conductive species, likely to produce an ion conductor (crystals). Therefore, from the viewpoint of easily joining solid materials at low temperatures, the adhesive of the present invention is preferably a mixture of a mixture of the phosphorus-containing molten salt and the ion-conductive species, and a solvent.

[0039] However, in the adhesive of the present invention, mixing the phosphorus-containing molten salt with water before mixing the phosphorus-containing molten salt with the ion-conductive species is not completely excluded, and the phosphorus-containing molten salt may be first mixed with a small amount of water in order to control viscosity and phosphorus condensation. In this case, the amount of water added may be 10 parts by mass or less per 100 parts by mass of the phosphorus-containing molten salt.

[0040] Because the adhesive of the present invention as described above does not burn, it is possible to bond powder materials together or powder materials to thin film materials even in the atmosphere at room temperature. Therefore, if the powder material is an ion conductor, it is possible to measure the ionic conductivity. Furthermore, because the adhesive of the present invention can be used in the atmosphere, it is possible to mass-produce products using heating and pressure rollers during the manufacturing process. Furthermore, if the powder material is an ion conductor, the resulting bonded body also has excellent heat resistance.

[0041] 2. Adhesive (Second Aspect) An adhesive according to a second aspect of the present invention is an adhesive used for bonding powder materials together or the powder material and a thin film material, and (2) contains a phosphorus-containing molten salt that is an ion conductor precursor, and the phosphorus-containing molten salt is a salt of an ion-conductive species of phosphoric acid.

[0042] The adhesive of the present invention is a material that includes not only liquid but also solid and gel forms. For example, the adhesive of the present invention may exist as an amorphous solid immediately after production, but when left standing in the air, it gradually absorbs moisture from the air and becomes gel-like, and over time it can liquefy.

[0043] (2-1) Phosphorus-Containing Molten Salt The phosphorus-containing molten salt is not particularly limited, but is an ion conductor precursor because it becomes an ion conductor due to the presence of an ion-conducting species, and thus allows bonding between powder materials or between the powder material and a thin film material via the ion conductor at low temperatures.

[0044] This phosphorus-containing molten salt is preferably liquid at room temperature (particularly 25° C.) because it is easy to handle in the air.

[0045] Furthermore, since the phosphorus-containing molten salt becomes an ion conductor due to the presence of ion-conducting species, bonding between powder materials or between the powder material and a thin film material via the phosphorus-containing ion conductor can be achieved at low temperatures, the melting temperature of the phosphorus-containing molten salt is preferably close to the heating temperature when the manufacturing method of the present invention described below is employed. For example, when the phosphorus-containing molten salt is sodium dihydrogen phosphate, it is preferably melted at 40 to 150°C, particularly 50 to 80°C.

[0046] The phosphorus-containing molten salt, which is an ion conductor precursor, employs a salt of an ion-conductive species of phosphoric acid. Examples of the salt of the ion-conductive species of phosphoric acid include alkali metal salts (sodium salt, potassium salt), alkaline earth metal salts (magnesium salt, calcium salt, etc.), etc.

[0047] Specific examples of such salts of ion-conductive species of phosphoric acid include hydrogen phosphates (sodium dihydrogen phosphate, potassium dihydrogen phosphate, calcium dihydrogen phosphate, sodium monohydrogen phosphate, potassium monohydrogen phosphate, calcium monohydrogen phosphate, etc.) These salts of ion-conductive species of phosphoric acid can be used alone or in combination of two or more.

[0048] In addition, as additive materials to the phosphorus-containing molten salt, for example, metal elements (transition metal elements such as vanadium, chromium, titanium, manganese, iron, cobalt, nickel, copper, zinc, hafnium, lanthanum, etc.; typical metal elements such as aluminum, gallium, indium, etc.), metalloid elements (boron, germanium, silicon, etc.), non-metal elements (nitrogen, fluorine, chlorine, bromine, iodine, sulfur, etc.), and their hydrides, oxides, carbides, carbonates, hydrates, and organic compounds such as amine compounds (methylamine, ethylamine, etc.) and carbamide compounds (urea, etc.) can also be used, and these can be used alone or in combination of two or more. Although not particularly limited, the content of various metal elements can be about 0 to 3 moles, and preferably about 0 to 0.5 moles, per mole of phosphorus in the inorganic phosphorus-containing molten salt in the inorganic phosphorus-containing molten salt. When these metal elements are used, the lower limit can be about 0.01 moles.

[0049] Furthermore, organic compounds such as amine compounds (methylamine, ethylamine, etc.), carbamide compounds (urea, etc.), guanidine compounds (guanidine, guanidine sulfide, arginine) may be contained. When the organic compound is urea, the amount of urea used may be about 0 to 3 moles, particularly about 0.1 to 0.5 moles, per mole of phosphorus.

[0050] The phosphorus-containing molten salt as described above may contain not only a salt of an ion-conductive species of phosphoric acid, but also a phosphorus-containing molten salt other than a salt of an ion-conductive species of phosphoric acid, for the purpose of adjusting the concentration of the ion-conductive species, etc.

[0051] Examples of phosphorus-containing molten salts other than salts of ion-conductive species of phosphoric acid include phosphoric acid, ammonium hydrogen phosphate salts (ammonium dihydrogen phosphate, ammonium monohydrogen phosphate, etc.), condensed phosphoric acids (orthophosphate, pyrophosphate, triphosphate, tetraphosphate, polyphosphate, etc.), organic phosphoric acid compounds (phosphine oxide, phosphonate ester, phosphate ester, etc.), etc. These phosphorus-containing molten salts other than salts of ion-conductive species of phosphoric acid can be used alone or in combination of two or more.

[0052] When a salt of an ion-conductive species of phosphoric acid and a phosphorus-containing molten salt other than the salt of an ion-conductive species of phosphoric acid are contained, the content of the salt of the ion-conductive species of phosphoric acid is not particularly limited, but is preferably 0.05 to 0.99 mol, more preferably 0.15 to 0.80 mol, based on 1 mol of the total amount of the phosphorus-containing molten salt. Similarly, the content of the phosphorus-containing molten salt other than the salt of the ion-conductive species of phosphoric acid is not particularly limited, but is preferably 0.01 to 0.95 mol, more preferably 0.20 to 0.85 mol, based on 1 mol of the total amount of the phosphorus-containing molten salt. The content of the salt of the ion-conductive species of phosphoric acid is not particularly limited, but is preferably 0 to 3.00 mol, more preferably 0.05 to 2.00 mol, based on 1 mol of the phosphorus-containing molten salt other than the salt of the ion-conductive species of phosphoric acid. When produced in air, 0.05 to 0.50 mol is even more preferable.

[0053] (2-2) Ion-conductive species In the adhesive according to the second aspect of the present invention, since the ion-conductive species is contained in the ion-conductive species of phosphoric acid, which is the phosphorus-containing molten salt, it is not necessary to contain an ion-conductive species separately from the phosphorus-containing molten salt. However, this does not preclude the inclusion of an ion-conductive species as described in (1-2) above separately from the phosphorus-containing molten salt. When an ion-conductive species as described in (1-2) above is included separately from the phosphorus-containing molten salt, the content of the phosphorus-containing molten salt is preferably 0.05 to 0.99 mol, more preferably 0.15 to 0.80 mol, based on 1 mol of the total amount of the phosphorus-containing compound and the ion-conductive species. Similarly, the content of the ion-conductive species is preferably 0.01 to 0.95 mol, more preferably 0.20 to 0.85 mol, based on 1 mol of the total amount of the phosphorus-containing molten salt and the ion-conductive species. The content of the ion-conducting species is not particularly limited, but is preferably 0 to 3.00 mol, more preferably 0.05 to 2.00 mol, relative to 1 mol of the phosphorus-containing molten salt, and when produced in air, is even more preferably 0.05 to 0.50 mol.

[0054] (2-3) Solvent The solvent that can be used for the adhesive of the present invention is not particularly limited, but because phosphate is generated by hydrolysis, it is preferable not to use water as a solvent when using the adhesive of the present invention as a solution to apply and bond materials. However, water can be used when applying the adhesive of the present invention between materials to generate phosphate and fix them.

[0055] The amount of water contained varies depending on the type of ionic conductor (such as a phosphorus-containing salt) to be produced by hydrolysis, but can be adjusted as appropriate.

[0056] (2-4) Adhesives The adhesives of the present invention that satisfy the above requirements can be used to bond powder materials together or powder materials and thin film materials. By incorporating an ion-conducting salt of phosphoric acid as the phosphorus-containing molten salt, the adhesives of the present invention can produce an ion-conducting solid at low temperatures and a viscous solution or gel upon heating. This solution or gel penetrates into the surface or pores of the parent phase, chemically and physically promoting bonding between solid materials. Therefore, there are no particular limitations on the types of powder materials and thin film materials to be bonded.

[0057] Examples of powder materials that can be used include ion conductors, electrode active materials, metal materials, organic materials, glass materials, wood materials, and ceramic materials. Examples of ion conductors that can be used include phosphorus-containing ion conductors (oxide solid electrolyte LiTa ２ P.O. ８ , Li ３ P.O. ４ etc; sulfide solid electrolyte Li １０ GeP ２ S １２ Examples of electrode active materials that can be used include LiCoO ２ , LiTiO ２ , LiFePO ４ , LiCoPO ４ , LiFeMnO ４ , Li ２ MnO ３ , LiMn ２ O ４Examples of usable metal materials include aluminum, stainless steel, and nickel. Examples of usable organic materials include polyethylene and polypropylene. Examples of usable glass materials include soda-lime glass, borosilicate glass, and phosphate glass. Examples of usable wood materials include pulp. Examples of usable ceramic materials include alumina, zirconia, and silicon carbide. These powder materials can be used alone or in combination of two or more.

[0058] Usable thin film materials include, for example, aluminum foil, copper foil, nickel foil, iron foil, etc. These thin film materials can be used alone or in combination of two or more.

[0059] In the adhesive of the present invention, the phosphorus-containing molten salt may be mixed with a small amount of water in order to control viscosity and phosphorus condensation. In this case, the amount of water added may be 10 parts by mass or less per 100 parts by mass of the phosphorus-containing molten salt.

[0060] Because the adhesive of the present invention as described above does not burn, it is possible to bond powder materials together or powder materials to thin film materials even in the atmosphere at room temperature. Therefore, if the powder material is an ion conductor, it is possible to measure the ionic conductivity. Furthermore, because the adhesive of the present invention can be used in the atmosphere, it is possible to mass-produce products using heating and pressure rollers during the manufacturing process. Furthermore, if the powder material is an ion conductor, the resulting bonded body also has excellent heat resistance.

[0061] 3. Adhesive (Third Aspect) An adhesive according to a third aspect of the present invention is an adhesive used for bonding powder materials together or the powder material and a thin film material, and (3) contains a phosphorus-containing molten salt that is an ion conductor precursor, and has ion-conducting species on the surface of the powder material.

[0062] The adhesive of the present invention is a material that includes not only liquid but also solid and gel forms. For example, the adhesive of the present invention may exist as an amorphous solid immediately after production, but when left standing in the air, it gradually absorbs moisture from the air and becomes gel-like, and over time it can liquefy.

[0063] (3-1) Phosphorus-containing molten salt As the phosphorus-containing molten salt, those described in (1-1) above can be used. Preferred specific examples are also the same.

[0064] (3-2) Ion-conductive species In the third aspect of the present invention, since the powder material has an ion-conductive species on its surface, it is not necessary to include an ion-conductive species separately from the phosphorus-containing molten salt. However, this does not preclude the inclusion of an ion-conductive species as described in (1-2) above separately from the phosphorus-containing molten salt. When an ion-conductive species as described in (1-2) above is included separately from the phosphorus-containing molten salt, the content of the phosphorus-containing molten salt is preferably 0.05 to 0.99 mol, more preferably 0.15 to 0.80 mol, based on 1 mol of the total amount of the phosphorus-containing compound and the ion-conductive species. Similarly, the content of the ion-conductive species is preferably 0.01 to 0.95 mol, more preferably 0.20 to 0.85 mol, based on 1 mol of the total amount of the phosphorus-containing molten salt and the ion-conductive species. The content of the ion-conducting species is not particularly limited, but is preferably 0 to 3.00 mol, more preferably 0.05 to 2.00 mol, relative to 1 mol of the phosphorus-containing molten salt, and when produced in air, is even more preferably 0.05 to 0.50 mol.

[0065] (3-3) Solvent The solvent that can be used for the adhesive of the present invention is not particularly limited, but because phosphate is generated by hydrolysis, it is preferable not to use water as a solvent when using the adhesive of the present invention as a solution to apply and bond materials. However, water can be used when applying the adhesive of the present invention between materials to generate phosphate and fix them.

[0066] The amount of water contained varies depending on the type of ionic conductor (such as a phosphorus-containing salt) to be produced by hydrolysis, but can be adjusted as appropriate.

[0067] (3-4) Adhesives The adhesives of the present invention that satisfy the above requirements can be used to bond powder materials together or powder materials to thin film materials. The adhesives of the present invention have ion-conducting species on the surface of the powder materials, and can form an ion-conducting solid at low temperatures and a viscous solution or gel upon heating. This solution or gel penetrates into the surface or pores of the parent phase, chemically and physically promoting bonding between solid materials.

[0068] As the ion-conducting species present on the surface of the powder material, those described in (1-2) above can be used.

[0069] Examples of powder materials that can be used include ion conductors, electrode active materials, metal materials, organic materials, glass materials, wood materials, and ceramic materials. Examples of ion conductors that can be used include phosphorus-containing ion conductors (oxide solid electrolyte LiTa ２ P.O. ８ , Li ３ P.O. ４ etc; sulfide solid electrolyte Li １０ GeP ２ S １２ Examples of electrode active materials that can be used include LiCoO ２ , LiTiO ２ , LiFePO ４ , LiCoPO ４ , LiFeMnO ４ , Li ２ MnO ３ , LiMn ２ O ４ Examples of usable metal materials include aluminum, stainless steel, and nickel. Examples of usable organic materials include polyethylene and polypropylene. Examples of usable glass materials include soda-lime glass, borosilicate glass, and phosphate glass. Examples of usable wood materials include pulp. Examples of usable ceramic materials include alumina, zirconia, and silicon carbide. These powder materials can be used alone or in combination of two or more.

[0070] Usable thin film materials include, for example, aluminum foil, copper foil, nickel foil, iron foil, etc. These thin film materials can be used alone or in combination of two or more.

[0071] In the adhesive of the present invention, the phosphorus-containing molten salt may be mixed with a small amount of water in order to control viscosity and phosphorus condensation. In this case, the amount of water added may be 10 parts by mass or less per 100 parts by mass of the phosphorus-containing molten salt.

[0072] Because the adhesive of the present invention as described above does not burn, it is possible to bond powder materials together or powder materials to thin film materials even in the atmosphere at room temperature. Therefore, if the powder material is an ion conductor, it is possible to measure the ionic conductivity. Furthermore, because the adhesive of the present invention can be used in the atmosphere, it is possible to mass-produce products using heating and pressure rollers during the manufacturing process. Furthermore, if the powder material is an ion conductor, the resulting bonded body also has excellent heat resistance.

[0073] 4. Manufacturing Method of Bonded Body The bonded body of the present invention between powder materials or the bonded body of the powder material and thin film material is not particularly limited, but can be obtained by a manufacturing method comprising: (I) a step of contacting the powder material, or the powder material and thin film material, with the adhesive of the present invention.

[0074] (4-1) Step (I) In step (I), the method for bringing the powder materials into contact with each other or the powder materials and thin film material into contact with the adhesive of the present invention is not particularly limited and can be carried out according to a conventional method. For example, they can be mixed in a mortar.

[0075] In step (I), the amount of the phosphorus-containing molten salt solution of the present invention to be added is not particularly limited, but is preferably 1,000 parts by mass or less, more preferably 0.01 to 150 parts by mass, relative to 100 parts by mass of the solid material, from the viewpoint of facilitating the production of an ionic conductor by hydrolysis and facilitating bonding between powder materials or between a powder material and a thin film material via the phosphorus-containing ionic conductor at low temperatures, while maintaining ease of molding. The lower limit of the amount of the phosphorus-containing molten salt solution of the present invention to be added can be, for example, 0.1 part by mass, 0.5 part by mass, etc.

[0076] In step (I), in order to facilitate forming a bonded body of powder materials or a bonded body of a powder material and a thin film material, a pressure treatment may be performed after mixing. In this case, the pressure to be applied is not particularly limited, but may be 1 to 1000 MPa, preferably 100 to 500 MPa.

[0077] The pressing time is not particularly limited, and can be set to 0.1 to 10 minutes, preferably 1 to 5 minutes, from the viewpoint of facilitating the formation of a bonded body of powder materials or a bonded body of a powder material and a thin film material.

[0078] (4-2) Step (II) In the method for producing a joined body of solid materials of the present invention, since the reaction between the phosphorus molten salt, water (including moisture in the atmosphere), and the ion-conducting species occurs even at low temperatures (−10° C. to room temperature), after the above step (1), it is possible to carry out, although not particularly essential, a step (2) of heating the mixture obtained in the step (1).

[0079] By controlling the viscosity of the adhesive of the present invention or by changing the degree of condensation of the adhesive of the present invention by heating, it is possible to allow the solution to penetrate into pores and irregularities between the materials or to increase the reactivity between the surfaces of the joining materials and phosphate ions, thereby making it easier to join the materials. In this case, the heating temperature is not particularly limited and varies depending on the type of ion conductor produced, but can be set to 30 to 500°C, preferably 50 to 250°C.

[0080] The heating time is not particularly limited and may be 0.1 to 10 hours, preferably 1 to 5 hours, although it may vary depending on the type of ionic conductor to be produced.

[0081] As described above, even if heat treatment is performed, the temperature is low, so that diffusion of elements at the bonding interface can be suppressed by heating, and it is possible to suppress the generation of impurity phases.

[0082] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0083] Synthesis Example 1: Method for Producing Phosphorus-Containing Molten Salt Phosphorus-containing molten salt was prepared using commercially available NH ４ H ２ P.O. ４ and pure water.

[0084] First, NH ４ H ２ P.O. ４ 0.57 g of the compound was dissolved in 15 mL of pure water, stirred, and then melted at 200°C or higher to obtain NH ４ H ２ P.O. ４ As a result, a transparent and viscous phosphorus-containing molten salt was prepared. ４ H ２ P.O. ４ Although a small amount of water is added to promote decomposition by heating, water does not necessarily have to be added.

[0085] The solution was collected, placed on a glass substrate, and subjected to powder X-ray diffraction measurement (CuKα: λ=1.5418 Å), resulting in the diffraction pattern shown in Figure 1. Since no clear diffraction peaks were observed, it became clear that the phosphorus-containing molten salt was a solution that did not contain crystals. Note that the peak observed near 2θ=25° in Figure 1 is a peak specific to amorphous materials.

[0086] The appearance of the obtained phosphorus-containing solution is shown in Figure 2, and the viscosity of the phosphorus-containing molten salt is shown in Figure 3. The higher the temperature, the lower the viscosity like water, but the lower the temperature, the higher the viscosity. Furthermore, the longer the heating time, the higher the viscosity. It is thought that the viscosity is related to the added materials, the amount of materials, and the degree of condensation of phosphorus.

[0087] Example 1: Manufacturing method of lithium-phosphorus-containing molten salt (adhesive) A transparent adhesive (Li:P=3:1 (molar ratio)) containing transparent or fine white precipitates was manufactured by adding lithium carbonate to the phosphorus-containing molten salt obtained in Synthesis Example 1 and melting the mixture. ３ P.O. ４ In order to produce the above, water is added to the molten salt of phosphoric acid, and the amount of P:Li is adjusted to 1:3 (molar ratio). ２ CO ３ and LiOH. ２ A Li source such as O can be added.

[0088] Furthermore, lithium carbonate was added to the phosphorus-containing molten salt obtained in Synthesis Example 1 in the air at room temperature (25°C), and the resulting adhesive of Example 1 was left in the air for 3 days. A material was produced having characteristic peaks at 2θ = 16°, 23°, 28°, 33°, 37°, and 44°, and a broad peak with weak intensity at 2θ = approximately 25°. This result indicates that the adhesive reacts with moisture in the air and partially crystallizes, while an amorphous material (lithium-phosphorus-containing molten salt) remains. Thus, the present invention allows crystallization by controlling the amount of ion-conductive species added to the phosphorus-containing molten salt, the amount of moisture added, and the timing of addition. Furthermore, when an ion-conductive species is added to the phosphorus-containing molten salt, heating can also be performed.

[0089] Figure 4 shows the X-ray diffraction pattern of the adhesive obtained in Example 1. In Figure 4, "Synthesis Example 1: Phosphorus-containing molten salt" refers to the salt obtained immediately after preparation in Example 1, "Example 1: Immediately after addition of Synthesis Example 1+Li2CO3" refers to the salt obtained before lithium carbonate was added to the phosphorus-containing molten salt in Example 1 and melted, "Example 1: Synthesis Example 1+Li2CO3 added (after 3 days in air without heating)" refers to the adhesive obtained by storing the sample of "Example 1: Immediately after addition of Synthesis Example 1+Li2CO3" in air without heating for 3 days, and "Li2CO3 powder" refers to the previously reported lithium carbonate.

[0090] Example 2: Manufacturing method of lithium-phosphorus-containing molten salt (adhesive) First, commercially available NH ４ H ２ P.O. ４ The adhesives were prepared by mixing commercially available lithium carbonate and P to Li at a molar ratio of 1:x (x = 0.5, 0.4, 0.3, 0.2, or 0.1) and melting at 210°C for 1.5 hours. The adhesives were poured into a quartz tube with an inner diameter of 10 mm, and aluminum foil was attached to both ends of the tube using finger pressure as electrodes. The adhesives were cooled to 25°C, and the solid or gel-like materials were used as measurement samples. The ionic conductivity of the samples was evaluated using an AC impedance method (100 MHz to 100 Hz) (Figure 5). The physical properties of the adhesive, such as viscosity versus temperature and ionic conductivity, vary depending on the amount or degree of condensation of the ion-conducting species and the added elements. In addition to the above, adhesives with a molar ratio of P:Li of 1:1 and P:Li of 1:2 were also prepared.

[0091] Example 3: Manufacturing Method of Silicon-Added Lithium-Phosphorus-Containing Molten Salt (Adhesive) 1.5 g of commercially available silica gel was crushed and added to 50 mL of pure water. The mixture was heated at 50°C or higher while stirring to produce a viscous, cloudy liquid. The cloudy liquid prepared in Example 2 was then added to the lithium-phosphorus-containing molten salt, the P:Li molar ratio of which had been adjusted to 1:0.2, to achieve a P:Si:Li molar ratio of 1:0.2:0.2. The mixture was then mixed and heated to produce an adhesive. The adhesive was poured into a quartz tube with an inner diameter of 10 mm, and aluminum foil was attached to both ends of the tube with finger pressure. The mixture was cooled to 25°C, and the solid or gel-like material was used as a measurement sample. The ionic conductivity of the sample was evaluated using an AC impedance method (100 MHz to 100 Hz) (Figure 6). The appearance of the resulting silicon-added, lithium- and phosphorus-containing molten salt (adhesive) is shown in Figure 7.

[0092] Example 4 20 mL of pure water was added to the lithium-phosphorus-containing molten salt (Li:P=3:1 (molar ratio)) obtained in Example 1. The appearance of the obtained solution is shown in Figure 8. It was found to be flexible, like wheat flour to which water had been added, and turned into powder over time. ２ P.O. ８ The resulting solution was added to the powder at 20% by mass and mixed in a mortar. Then, using a 10 mm diameter tablet press and a uniaxial press, the mixture was pressurized at 300 MPa for 3 minutes, followed by molding into ionic conductor junction pellets by (1) leaving the mixture in the air, (2) heating at 150°C for 2 hours, or (3) heating at 200°C for 2 hours. To evaluate the pellets, Au current collecting films were formed on the front and back surfaces of the sintered compacts by sputtering, and the ionic conductivity was measured by an AC impedance method (100 MHz to 100 Hz) ( FIG. 9 ). X-ray diffraction (XRD) measurements ( FIG. 10 ) and cross-sectional scanning electron microscope (SEM) observations ( FIG. 11 ) were then performed.

[0093] Example 5 The phosphorus-containing molten salt obtained in Synthesis Example 1 was preliminarily mixed with a commercially available oxide solid electrolyte, LiTa. ２ P.O. ８ Commercially available Li powder ２ CO ３The mixture was then mixed in a mortar with a mixture of P and Li powder (measured so that the molar ratio of P:Li was 1:3). The mixture was then pressurized at 300 MPa for 3 minutes using a tablet press with a diameter of 10 mm and a uniaxial press, and left in the air for 3 days to obtain an ion conductor assembly. The amount of the phosphorus solution was adjusted to 1:1. ２ P.O. ８ The amount of the powder was 1 mass %, 5 mass %, or 10 mass %.

[0094] The pellets obtained were evaluated by X-ray diffraction (XRD) measurement (FIG. 12) and cross-sectional scanning electron microscope (SEM) observation (FIG. 13). The appearance of the pellets obtained is shown in FIG. 14. The amount of phosphorus solution was adjusted to 1000 ppm by weight of the solid electrolyte LiTa. ２ P.O. ８ An attempt was made to produce pellets containing 100% by mass of the powder, but the pellets became brittle and could not be molded due to the generation of carbon dioxide due to hydrolysis.

[0095] Example 6 In Example 1, a lithium-phosphorus-containing molten salt adjusted to Li:P=1:0.05 (molar ratio) was added to a commercially available positive electrode active material LiCoO ２ Separately, a lithium-phosphorus-containing molten salt adjusted to Li:P=1:1 (molar ratio) in Example 1 was added to a commercially available solid electrolyte LiTa ２ P.O. ８ Separately, a commercially available negative electrode active material, LiTaO ２ The mixture was added to a powder mixture of Al / positive electrode (LiCoO ２ ) / electrolyte layer (LiTa ２ P.O. ８ ) / Negative electrode (LiTaO ２ The all-solid-state battery was fabricated by laminating the ZnO and ZnO in air. The heating temperature was 200°C to accelerate film formation.

[0096] The battery was evaluated by constant voltage charge / discharge measurements (0.5 mV / sec) (Fig. 15). Assuming that the fabricated battery behaves as a resistor, V = IR, so the behavior should be linear. However, the measurement results showed a curve with a constant area during charge / discharge, suggesting that some kind of reaction was occurring during charge / discharge.

[0097] Reference Example 1: The above examples demonstrated that the phosphorus-containing molten salt solution of the present invention can bond ionic conductors. Meanwhile, other materials, such as aluminum foil (aluminum), a medicine spoon (stainless steel), a prepared slide (glass), a plastic bag (polyethylene), and Kimwipes (pulp), were bonded using the lithium-containing phosphorus solution obtained in Example 1. The results are shown in Figure 16. Because the adhesive of the present invention has high viscosity and contains phosphorus, it is possible that the bonding occurs due to surface corrosion of the materials by the phosphoric acid or by infiltration into minute gaps between the materials or hardening.

[0098] Reference Example 2 The ion-conducting species / phosphorus-containing molten salt (adhesive) obtained in Example 1 was added to a large amount of tap water. The process is shown in Figure 17. As a result, Li was hydrolyzed. ３ P.O. ４ was seen to be generated.

[0099] Reference Example 3: The ion-conducting species / phosphorus-containing molten salt (adhesive) obtained in Example 2 and a commercially available positive electrode active material, LiMn ２ O ４ A mixture of the adhesive and the commercially available conductive additive acetylene black (10% by mass relative to the positive electrode active material) was applied to aluminum foil, cooled at 25°C, and then added to a large amount of tap water. The process is shown in Figure 18. As a result, the material applied to the aluminum foil peeled off due to hydrolysis, and it can be seen that materials bonded with the adhesive of the present invention can be easily peeled off.

[0100] Example 7: Manufacturing method of adhesive (carbonate of Group 1 or 2 element of the periodic table) First, commercially available NH ４ H ２ P.O. ４ and a commercially available compound containing an element of Group 1 or Group 2 of the periodic table (Na２ CO ３ , K. ２ CO ３ , MgO, or CaCO ３ ) was used, and the molar ratio of phosphorus to a compound having an element of Group 1 or 2 of the periodic table was ２ CO ３ and K. ２ CO ３ In the case of , the amount of P: the amount of Na or K = 1:0.2, MgO, or CaCO ３ In the case of (1), the amount of P: the amount of Ca or Mg was mixed so that the ratio was 1:0.05, and the mixture was heated at 210° C. for 1.5 hours to prepare an adhesive.

[0101] The prepared adhesive was poured into a quartz tube with an inner diameter of 10 mm, and aluminum foil was used as electrodes and attached to both ends of the quartz tube with finger pressure. The adhesive was then cooled to 25°C, and the solid or gel-like material was used as the measurement sample. The ionic conductivity of the sample was evaluated using the AC impedance method (100 MHz to 100 Hz). The Bode plot and external appearance photograph obtained by the measurement are shown in Figure 19.

[0102] Example 8: Manufacturing method of adhesive (transition metal oxide added) First, commercially available NH ４ H ２ P.O. ４ and commercially available lithium carbonate and commercially available transition metal oxide (Nb ２ O ５ , W ２ O ３ , MoO ３ , ZrO, Ta ２ O ５ , CrO ２ , TiO ２ , V ２ O ３ , La ２ O ３ , CeO ２ , HfO ２ , Fe ２ O ３ , MnO ２ , Co ３ O ４ , or NiO ２) was used, and phosphorus, lithium, and transition metal oxide were mixed in a molar ratio of P amount:Li amount:various transition metal amount=1:0.2:0.2, and heated at 210°C for 1.5 hours to prepare an adhesive.

[0103] The prepared adhesive was poured into a quartz tube with an inner diameter of 10 mm, and aluminum foil was used as electrodes and attached to both ends of the quartz tube with finger pressure. The adhesive was then cooled to 25°C, and the solid or gel-like material was used as the measurement sample. The ionic conductivity of the sample was evaluated using the AC impedance method (100 MHz to 100 Hz). The Bode diagrams and external appearance photographs obtained by the measurement are shown in Figures 20 to 22.

[0104] Example 9: Manufacturing method of adhesive (with oxide of Group 13 element of the periodic table added) First, a commercially available NH ４ H ２ P.O. ４ and commercially available lithium carbonate and commercially available oxides of group 13 elements of the periodic table (B ２ O ３ , Al ２ O ３ , or InO ２ ) was used, and phosphorus, lithium, and an oxide of a Group 13 element of the periodic table were mixed in a molar ratio of 1:0.2:0.2, and heated at 210°C for 1.5 hours to prepare an adhesive.

[0105] In addition, NH ４ H ２ P.O. ４ , lithium carbonate, and gallium oxide (Ga ２ O ３ ) was used, and phosphorus, lithium, and gallium oxide were mixed so that the molar ratio of P amount:Li amount:Ga amount was 1:0.2:0.2, and the mixture was heated at 210°C for 1 hour and at 220°C for 30 minutes to prepare an adhesive.

[0106] The prepared adhesive was poured into a quartz tube with an inner diameter of 10 mm, and aluminum foil was used as electrodes and attached to both ends of the quartz tube with finger pressure. The adhesive was then cooled to 25°C, and the solid or gel-like material was used as the measurement sample. The ionic conductivity of the sample was evaluated using the AC impedance method (100 MHz to 100 Hz). The Bode plot and external appearance photograph obtained by the measurement are shown in Figure 23.

[0107] Example 10: Manufacturing method of adhesive (with oxide of Group 14 element of the periodic table added) First, commercially available NH ４ H ２ P.O. ４ and commercially available lithium carbonate and commercially available oxides of group 14 elements of the periodic table (SiO ２ , or GeO ２ ) was used, and phosphorus, lithium, and an oxide of a Group 14 element of the periodic table were mixed in a molar ratio of P amount:Li amount:Group 14 element amount=1:0.2:0.2, and the mixture was heated at 210°C for 1.5 hours to prepare an adhesive.

[0108] The prepared adhesive was poured into a quartz tube with an inner diameter of 10 mm, and aluminum foil was used as electrodes and attached to both ends of the quartz tube with finger pressure. The adhesive was then cooled to 25°C, and the solid or gel-like material was used as the measurement sample. The ionic conductivity of the sample was evaluated using the AC impedance method (100 MHz to 100 Hz). The Bode plot and external appearance photograph obtained by the measurement are shown in Figure 24.

[0109] Example 11: Manufacturing method of adhesive (halogen ion added) First, a commercially available NH ４ H ２ P.O. ４ and a commercially available halide (LiF, LiCl, LiBr, or LiI) were weighed out so that the molar ratio of phosphorus to halogen was 1:0.2 (amount of P:amount of halogen).

[0110] After that, NH ４ H ２ P.O. ４ The chisel was heated at 210°C for 1 hour, then mixed with a halide, and heated at 220°C for 0.5 hour to prepare an adhesive.

[0111] The prepared adhesive was poured into a quartz tube with an inner diameter of 10 mm, and aluminum foil was used as electrodes and attached to both ends of the quartz tube by finger pressure. The adhesive was then cooled to 25°C, and the solid or gel-like material was used as the measurement sample. The ionic conductivity of the sample was evaluated using the AC impedance method (100 MHz to 100 Hz). The Bode plot and external appearance photograph obtained by the measurement are shown in Figure 25.

[0112] Example 12: Manufacturing method of adhesive (carbonate of Group 11 or 12 element of the periodic table) ４ H ２ P.O. ４ and commercially available lithium carbonate and a commercially available compound containing Cu or Zn (CuCO ３ Cu(OH) ２ ・H ２ O, or [ZnCO ３ ] ２ [Zn(OH) ２ ] ３ ) was used, and phosphorus, lithium, and copper or zinc were mixed in a molar ratio of P amount:Li amount:Cu or Zn amount=1:0.2:0.2, and heated at 210° C. for 1.5 hours to prepare a phosphorus-containing molten salt.

[0113] The prepared phosphorus-containing molten salt was poured into a quartz tube with an inner diameter of 10 mm, and aluminum foil was attached to both ends of the quartz tube using finger pressure as electrodes. The molten salt was then cooled to 23°C, and the solid or gel-like salt was used as a measurement sample. The ionic conductivity of the sample was evaluated using an AC impedance method (100 MHz to 100 Hz). The Bode plots and external appearance photographs obtained by the measurement are shown in Figures 26 and 27.

[0114] Example 13: Manufacturing method of adhesive (urea) Commercially available NH ４ H ２ P.O. ４ and commercially available lithium carbonate and commercially available urea (CO(NH ２ ) ２ ) was used, and phosphorus, lithium, and nitrogen (ammonium ion) in urea were mixed so that the ratio of P amount:Li amount:N amount=1:0.2:0.2, and the mixture was heated at 210°C for 1.5 hours to prepare a phosphorus-containing molten salt.

[0115] The prepared phosphorus-containing molten salt was poured into a quartz tube with an inner diameter of 10 mm, and aluminum foil was attached to both ends of the quartz tube using finger pressure as electrodes. The molten salt was then cooled to 23°C, and the solid or gel-like salt was used as a measurement sample. The ionic conductivity of the sample was evaluated using an AC impedance method (100 MHz to 100 Hz). The Bode plot and external appearance photograph obtained by the measurement are shown in Figures 26 and 28.

Claims

1. An adhesive substance intended for use in bonding particles of a powder material to each other or bonding a powder material to a thin film material, wherein the adhesive substance satisfies the following: (1) contains a phosphorus-containing molten salt, which is a precursor of an ionic conductor, and an ion-conducting substance; (2) contains a phosphorus-containing molten salt that is a precursor to an ionic conductor, wherein the phosphorus-containing molten salt is a salt of the ionic conductor of phosphoric acid; or (3) contains a phosphorus-containing molten salt which is a precursor of an ionic conductor, and the powder material has an ion-conducting substance on its surface.

2. The adhesive according to claim 1, wherein the powder material is at least one selected from the group consisting of an ionic conductor, an electrode active material, a metallic material, an organic material, a glass material, and a ceramic material.

3. An adhesive according to claim 1 or 2, wherein the adhesive is a liquid, gel or solid.

4. An adhesive according to any one of claims 1 to 3, wherein the phosphorus-containing molten salt is at least one selected from the group consisting of phosphoric acid, hydrogen phosphate, condensed phosphoric acid, and an organophosphate compound.

5. An adhesive according to any one of claims 1 to 4, wherein the ion-conducting substance comprises at least one selected from the group consisting of an alkali metal ion and an alkaline earth metal ion.

6. An adhesive according to any one of claims 1 to 5, wherein the adhesive satisfies condition (1) and is a mixture comprising a mixture of a phosphorus-containing molten salt and an ion-conducting substance and a solvent.

7. A method for producing a bonded body from particles of a powder material or a bonded body from a powder material and a thin-film material, comprising: (I) bringing the powder material or the powder material and the thin film material into contact with the adhesive according to claim 1 or 2.

8. The production method according to claim 7, wherein at step (I) after contact, pressure treatment is carried out.

9. The method of obtaining according to paragraph 7, additionally including: (II) heating the mixture obtained in step (1).

10. The production method according to claim 9, wherein heating in stage (II) is carried out at a temperature of 30-500°C.