Composition, method for manufacturing coated active material, method for manufacturing battery, and battery

Abstract

To provide a technology for realizing an active material that can improve the charge / discharge capacity of a battery.SOLUTION: A composition according to the present disclosure includes an organic solvent, an organic substance, and an active material, the solubility of the organic substance in the organic solvent is greater than 10 g / L, and the following (A) or (B) is satisfied. (A) the solubility of the organic substance in water is 10 g / L or less, and (B) an aqueous solution of the organic substance has a pH of 7 or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a composition, a method for manufacturing a coating active material, a battery, and a method for manufacturing a battery.

Background Art

[0002] Patent Document 1 discloses a method for manufacturing an active material coated with carbon.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the prior art, development of an active material having high electronic conductivity and capable of improving battery characteristics is desired. The present disclosure provides a technique for realizing an active material capable of improving the charging capacity of a battery.

Means for Solving the Problems

[0005] The composition in one aspect of the present disclosure is an organic solvent, an organic substance, an active material, and the solubility of the organic substance in the organic solvent is greater than 10 g / L, and the following (A) or (B) is satisfied. (A) The solubility of the organic substance in water is 10 g / L or less. (B) The pH of an aqueous solution of the organic substance is 7 or more.

Effects of the Invention

[0006] According to the present disclosure, a technique for realizing an active material capable of improving the charging capacity of a battery is provided.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0008] <Inventor's Focus> Conventionally, in the field of secondary batteries that require high energy density and large capacity, it has been mainstream to use an organic electrolyte solution in which an electrolyte salt is dissolved in an organic solvent. In a secondary battery using an organic electrolyte solution (hereinafter referred to as a "liquid battery"), there is a concern about liquid leakage, and it has been pointed out that the amount of heat generated in the event of a short circuit or the like may increase.

[0009] On the other hand, all-solid-state secondary batteries using an inorganic solid electrolyte instead of an organic electrolyte solution have been attracting attention. All-solid-state secondary batteries do not cause liquid leakage. Since the inorganic solid electrolyte is not flammable, it is expected that heat generation in the event of a short circuit or the like is also suppressed.

[0010] In both liquid batteries and all-solid-state secondary batteries, in order to further improve the charge-discharge capacity, the use of electrode materials with high energy density has been studied. However, many electrode materials with high energy density cause volume expansion and contraction during charge and discharge, and in particular, in all-solid-state secondary batteries, they can be a factor in deteriorating durability.

[0011] Examples of active materials with small volume expansion and contraction include lithium oxide-based materials, but many of these materials generally have low electronic conductivity and have the problem of a decrease in charge-discharge capacity.

[0012] Therefore, the inventors studied a method for enhancing the electronic conductivity of a material with low electronic conductivity and improving the charge-discharge capacity of a battery. As a result, it has been found that by coating the surface of an active material containing V element with a solution in which a specific organic substance is dissolved in a specific solvent, it is possible to enhance the electronic conductivity of the active material and improve the charging capacity of the battery. Based on the above viewpoints, the configuration of the present disclosure has been obtained.

[0013] (Embodiment 1) The composition according to Embodiment 1 includes an organic solvent, an organic substance, and an active material. The solubility of the organic substance in the above organic solvent is greater than 10 g / L. In the composition according to Embodiment 1, the following (A) or (B) is satisfied. (A) The solubility of the above organic substance in water is 10 g / L or less. (B) The pH of the aqueous solution of the above organic substance is 7 or more.

[0014] In the present disclosure, "the solubility of the organic substance in the organic solvent is greater than 10 g / L" means that at 25°C, the amount of organic solvent required to dissolve 10 g of the organic substance is less than 1 L. Here, dissolution means satisfying both the condition that there is no turbidity in the solution obtained when the solute is dissolved in the organic solvent in the container and the condition that no precipitate is confirmed on the bottom of the container after the solution is allowed to stand for 24 hours. When the organic solvent contained in the composition is a mixed solvent, "the solubility of the organic substance in the organic solvent" means the solubility in the mixed solvent. At 25°C, the solubility of the organic substance in the organic solvent may be 100 g / L or more.

[0015] In the present disclosure, "the solubility of the organic substance in water is 10 g / L or less" means that at 25°C, the amount of water required to dissolve 10 g of the organic substance is 1 L or more. Dissolution means satisfying both the condition that there is no turbidity in the aqueous solution obtained when the solute is dissolved in the water in the container and the condition that no precipitate is confirmed on the bottom of the container after the aqueous solution is allowed to stand for 24 hours.

[0016] The pH of the aqueous solution of the organic substance is measured, for example, at a concentration of 0.1 mol / L of the organic substance. When an aqueous solution of 0.1 mol / L of the organic substance cannot be prepared, it is measured by the solubility of the organic substance. Therefore, in the present disclosure, "the pH of the aqueous solution of the organic substance is 7 or more" means that the pH of the 0.1 mol / L aqueous solution of the organic substance is 7 or more, and when an aqueous solution of 0.1 mol / L of the organic substance cannot be prepared, the pH of the saturated aqueous solution of the organic substance is 7 or more. In the composition according to Embodiment 1, when the above (B) is satisfied, the pH of the 0.1 mol / L aqueous solution of the above organic substance may be 7 or more.

[0017] The composition may be in the form of a paste or in the state of a dispersion. The active material is, for example, particulate. In the composition, the particles of the active material are, for example, mixed with an organic solvent. The viscosity of the composition can be adjusted as appropriate. For example, when the viscosity of the composition is relatively low, the composition can be dried by a method such as the spray method to remove the organic solvent. When the viscosity of the composition is relatively high, the composition can be dried by a method such as heat drying to remove the organic solvent.

[0018] In a preferred form of the present disclosure, the organic solvent may contain a compound having a linear structure. By using a compound having a linear structure, a composition excellent in the suspension stability of the active material can be obtained.

[0019] The number of carbon atoms in the compound contained in the organic solvent is not particularly limited and may be 8 or less. When the organic solvent is a mixed solvent, the number of carbon atoms of each compound constituting the mixed solvent may also be 8 or less. According to the above, since the organic solvent is easy to volatilize, the composition can be easily dried to remove the organic solvent.

[0020] In another preferred embodiment of the present disclosure, the organic solvent may contain a compound having a ring structure. The organic solvent may have an aromatic ring. The ring structure may be an alicyclic hydrocarbon or an aromatic hydrocarbon. The ring structure may be monocyclic or polycyclic. By having a ring structure, the active substance can be easily dispersed in the compound. From the viewpoint of enhancing the suspension stability of the active substance in the composition, the organic solvent may contain an aromatic compound.

[0021] The organic solvent may have only a hydroxy group as a functional group. By using such an organic solvent, the active substance can be easily dispersed in the composition. Therefore, a composition excellent in the suspension stability of the active substance can be obtained.

[0022] The organic solvent may contain a monohydric alcohol. The organic solvent may consist only of a monohydric alcohol. By using such an organic solvent, the active substance can be easily dispersed in the composition. Therefore, a composition excellent in the suspension stability of the active substance can be obtained.

[0023] The monohydric alcohol may be such that the portion other than the hydroxy group is composed only of carbon and hydrogen. That is, the monohydric alcohol may be a compound in which one of the hydrogen atoms contained in a hydrocarbon is substituted with a hydroxy group.

[0024] The monohydric alcohol may have a structure in which one hydrogen atom of a hydrocarbon having a linear structure is substituted with a hydroxy group, or may have a structure in which one hydrogen atom at the end of a hydrocarbon having a linear structure is substituted with a hydroxy group.

[0025] The number of carbons contained in the monohydric alcohol is not particularly limited and may be 8 or less. Thereby, since the monohydric alcohol is volatile, the composition can be easily dried to remove the monohydric alcohol. The number of carbons contained in the monohydric alcohol may be 1 or more, or may be 2 or more.

[0026] The monohydric alcohol may, for example, have a portion other than the hydroxy group that does not contain a heteroatom. According to such a configuration, the active material can be easily dispersed in the compound. Examples of heteroatoms are N, P, O, and S.

[0027] The organic solvent may contain at least one selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, and water.

[0028] The organic solvent may contain at least one selected from the group consisting of methanol, ethanol, 1-propanol, and 2-propanol.

[0029] The organic solvent may contain ethanol. The organic solvent may consist only of ethanol.

[0030] According to the above configuration, the active material can be easily dispersed in the composition. Also, the composition can be easily dried to remove the organic solvent. By using ethanol, in particular, the composition can be easily dried to remove the organic solvent.

[0031] The organic solvent may be a mixed solvent of two or more selected from the above solvents.

[0032] The organic solvent may contain a solvent composed only of carbon and hydrogen. That is, it may contain a hydrocarbon.

[0033] The boiling point of the organic solvent is not particularly limited and may be 60°C or higher and 200°C or lower. The organic solvent may be a liquid at 25°C. Such an organic solvent is less likely to volatilize at room temperature, so the active material can be stably dispersed. Also, thereby, the organic solvent can be easily removed. The organic solvent may be any liquid that can disperse the active material, and the active material does not dissolve in the solvent.

[0034] The values of the polar term δp and the dispersion term δd in the Hansen solubility parameter (HSP) of an organic solvent are not limited to specific values. The Hansen solubility parameter (HSP) is a parameter that represents the dissolution characteristics between substances. In the present disclosure, HSP means a parameter of a vector quantity obtained by decomposing the solubility parameter of Hildebrand into three cohesive energy components of London dispersion force, dipole-dipole force, and hydrogen bond. In the present disclosure, the component corresponding to the London dispersion force of HSP is described as the dispersion term δd, and the component corresponding to the dipole-dipole force is described as the polar term δp. The unit of δp is, for example, MPa 1 / 2 or the like. The values of the HSP of an organic solvent can be obtained, for example, by referring to a database. In the case of an organic solvent for which the value of HSP is not registered in the database, the value of HSP can be calculated from the chemical structure of the organic solvent by using computer software such as Hansen Solubility Parameters in Practice (HSPiP).

[0035] The hydrogen bond term δh, which is the component corresponding to the hydrogen bond of the HSP of the organic solvent, is greater than 14 MPa 1 / 2 and may be less than 26 MPa 1 / 2 Thereby, in the composition, the organic matter can be easily dissolved in the organic solvent, and the active substance can be stably dispersed in the organic solvent.

[0036] The hydrogen bond term δh of the HSP value of the organic solvent is 16 MPa 1 / 2 or more and 23 MPa 1 / 2 or less, and may be 16 MPa 1 / 2 or more and 20 MPa 1 / 2 or less. Thereby, in the composition, the organic matter can be easily dissolved in the organic solvent, and the active substance can be stably dispersed in the organic solvent.

[0037] According to the above configuration, a composition capable of improving the charge and discharge capacity of a battery can be provided. The composition of the present disclosure has high electronic conductivity and is suitable for manufacturing an active material member capable of improving the charge and discharge capacity. For example, when the composition of the present disclosure is dried to remove the organic solvent, an active material member having high electronic conductivity can be obtained. The active material member may be a coated active material in which the surface of the active material particles is coated with a conductive material. Alternatively, the active material member may be an active material film containing an active material and a conductive material.

[0038] The organic substance may have a hydroxy group. The organic substance does not necessarily have a carboxy group. The organic substance may have a hydroxy group and not have a carboxy group.

[0039] The organic substance may have a benzene ring. By having a benzene ring, a coating having good crystallinity can be formed on the surface of the active material. Therefore, an active material having high electronic conductivity and a composition capable of improving the charge and discharge capacity of a battery can be provided.

[0040] The organic substance may contain phenols. Thereby, an active material having high electronic conductivity and a composition capable of improving the charge and discharge capacity of a battery can be provided.

[0041] The phenols are, for example, bisphenols. The organic substance may contain bisphenols. Thereby, an active material having high electronic conductivity can be provided. The bisphenols are, for example, bisphenol A, bisphenol AP, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol P, bisphenol PH, bisphenol TMC, or bisphenol Z, and may be bisphenol A.

[0042] More specifically, the organic substance may contain bisphenol A. Thereby, an active material having high electronic conductivity and a composition capable of improving the charge and discharge capacity of a battery can be provided.

[0043] The organic substance may include a high molecular compound. Examples of the high molecular compound include polysaccharides and polyphenols.

[0044] The high molecular compound may be at least one selected from the group consisting of ethyl cellulose and polyphenol. The high molecular compound may be ethyl cellulose. Since ethyl cellulose has a large number of hydroxy groups in its structure, it can selectively adsorb on the surface of the active material and form a good coating state.

[0045] The organic substance may include sugar. Since sugar has a large number of hydroxy groups in its structure, it can selectively adsorb on the surface of the active material and form a good coating state. In the present disclosure, the sugar also includes sugar alcohols.

[0046] The sugar may be at least one selected from the group consisting of monosaccharides and sugar alcohols. Examples of the monosaccharide are mannose and fructose. Examples of the sugar alcohol are sorbitol and xylitol.

[0047] The sugar may be a monosaccharide.

[0048] The sugar may include at least one selected from the group consisting of fructose, mannose, sorbitol, and xylitol.

[0049] The sugar may include fructose. By using fructose, the dissolution amount of the organic substance in the organic solvent can be increased.

[0050] According to the above configuration, a composition capable of improving the charge and discharge capacity of the battery can be provided.

[0051] In the composition according to Embodiment 1, the content ratio of the organic substance may be 0.2% by mass or more and 20.0% by mass or less, and may also be 0.2% by mass or more and 15.0% by mass or less.

[0052] The ratio of the mass of the active material to the total of the mass of the active material and the mass of the solvent is not particularly limited and may be 10% by mass or less. According to such a configuration, for example, a composition that can be easily dried using a spray method can be obtained.

[0053] The active material includes a material having a property of occluding and releasing metal ions (for example, lithium ions). The active material may be a negative electrode active material or a positive electrode active material.

[0054] The active material may be a negative electrode active material. At this time, the composition of the present disclosure can provide a negative electrode active material having high electronic conductivity and capable of improving the charge and discharge capacity.

[0055] The active material may contain a V element. In order to improve the electronic conductivity of the active material containing the V element, when coating the surface of the active material, the active material containing V such as vanadium oxide has a problem that it is particularly likely to dissolve and decompose in a solvent such as water. The composition of the present disclosure can suppress the dissolution and decomposition of the active material containing V, and can realize an improvement in the electronic conductivity of the active material and an improvement in the charge and discharge capacity of the battery.

[0056] The active material may be a composite oxide containing lithium and vanadium.

[0057] The active material may be a compound represented by the following compositional formula (1). Li 3+x+a V 1-x M x O 4+a / 2 ···Formula (1) Here, M is at least one selected from the group consisting of tetravalent metal elements and tetravalent metalloid elements, and the compositional formula (1) satisfies 0 ≦ a < 1 and 0 ≦ x < 1.

[0058] The compositional formula (1) may satisfy 0 ≦ x ≦ 0.15. Thereby, the charge and discharge capacity of the battery can be improved.

[0059] The compositional formula (1) may satisfy 0 < x ≦ 0.15. Thereby, the charge and discharge capacity of the battery can be improved.

[0060] Examples of the tetravalent metal element and the tetravalent metalloid element include Ti, Zr, Si, Ge, Sn, etc. In Composition Formula (1), M may contain at least one selected from the group consisting of Ti, Zr, Si, Ge, and Sn. Thereby, the charge-discharge capacity of the battery can be improved.

[0061] In Composition Formula (1), M may contain Ti. Thereby, the charge-discharge capacity of the battery can be improved.

[0062] The shape of the active material is not limited. Examples of the shape are needle-like, spherical, or ellipsoidal. The active material according to Embodiment 1 may be particles. The active material may be formed to have the shape of a pellet or a plate.

[0063] When the shape of the active material is, for example, particulate (e.g., spherical), the active material may have a median diameter of 0.1 μm or more and 100 μm or less, and preferably may have a median diameter of 0.5 μm or more and 10 μm or less. Thereby, the composition according to Embodiment 1 can provide an active material having higher lithium diffusivity. Further, when the active material is mixed with other materials such as a solid electrolyte, the dispersion state of the active material and the other materials becomes good. The median diameter means the particle diameter when the cumulative volume in the volume-based particle size distribution is equal to 50%. The volume-based particle size distribution is measured by, for example, a laser diffraction type measuring device or an image analysis device.

[0064] The active material may not dissolve in the organic solvent. The solubility of the active material in 100 mL of the organic solvent in the composition according to Embodiment 1 at 25°C may be, for example, less than 0.1 g. That is, more than 100 mL of the above organic solvent may be required to dissolve 0.1 g of the active material at 25°C. According to the above, decomposition and structural collapse of the active material can be suppressed. When the organic solvent contained in the composition is a mixed solvent, the above solubility of the active material means the solubility in the mixed solvent.

[0065] The composition according to Embodiment 1 may further contain another substance other than those described above. For example, the composition may contain a binder.

[0066] By containing a binder, the binding property between particles can be enhanced when the composition is dried as described later.

[0067] Examples of the binder include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, methyl polyacrylate ester, ethyl polyacrylate ester, hexyl polyacrylate ester, polymethacrylic acid, methyl polymethacrylate ester, ethyl polymethacrylate ester, hexyl polymethacrylate ester, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene-butadiene rubber, or carboxymethyl cellulose. Copolymers can also be used as the binder. Examples of such binders are copolymers of two or more materials selected from the group consisting of tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene. A mixture of two or more selected from the above materials may be used as the binder.

[0068] (Embodiment 2) Hereinafter, Embodiment 2 will be described. The same explanations as those in Embodiment 1 described above will be omitted as appropriate.

[0069] The method for producing a coating active material according to Embodiment 2 is (A) drying the composition according to Embodiment 1 and includes.

[0070] By removing the organic solvent by drying the composition, for example, a coating active material uniformly coated with an organic substance can be produced. As a result, the coating active material has high electronic conductivity. Such a coating active material can be used to obtain a battery having excellent charge and discharge characteristics. The coating active material produced by the manufacturing method according to Embodiment 2 is suitable for improving the battery capacity, for example. An example of the battery is an all-solid-state battery. The all-solid-state battery may be a primary battery or a secondary battery.

[0071] (A) is performed, for example, by heating the composition. The heating temperature may be, for example, 50°C or higher and 200°C or lower. The heating time may be, for example, 30 minutes or longer and 24 hours or shorter. The drying may be performed under atmospheric pressure or may be vacuum drying. That is, the solvent may be removed by vacuum drying.

[0072] Vacuum drying means drying the composition in an atmosphere at a pressure lower than atmospheric pressure. The atmosphere at a pressure lower than atmospheric pressure may be, for example, a gauge pressure of -0.01 MPa or lower. In vacuum drying, the composition may be heated to, for example, 50°C or higher and 200°C or lower.

[0073] The organic solvent may be removed by vacuum drying. Vacuum drying means, for example, removing the compound by drying the composition at a vapor pressure equal to or lower than the vapor pressure at a temperature 20°C lower than the boiling point of the compound.

[0074] The removal of the organic solvent can be confirmed, for example, by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), gas chromatography (GC), or gas chromatography-mass spectrometry (GC / MS). In the present disclosure, removing the organic solvent means performing a treatment for removing the organic solvent, such as drying the composition, and does not mean completely removing all of the organic solvent. That is, it is sufficient that the coating active material obtained after drying has electronic conductivity, and the organic solvent does not have to be completely removed from the composition.

[0075] The method for producing a coated active material according to Embodiment 2 is (B) carbonizing the organic matter by heat treatment may further be included.

[0076] By carbonizing the organic matter, active material particles uniformly coated with conductive carbon can be produced.

[0077] The temperature of the heat treatment is not particularly limited as long as it is a temperature at which the organic matter carbonizes, and for example, it may be 500°C or higher and 900°C or lower. The heat treatment may be 3 hours or longer and 72 hours or shorter. The heat treatment may be performed in a vacuum atmosphere or an inert atmosphere. The inert atmosphere may be, for example, a nitrogen atmosphere or an argon atmosphere.

[0078] In the method for producing a coated active material according to Embodiment 2, (B) may be performed after (A). That is, after drying the composition, the composition may be heat-treated to carbonize the organic matter. (A) and (B) may be performed continuously, or another treatment may be performed between (A) and (B). For example, after (A) and before (B), crushing of the dried composition may be performed.

[0079] (A) and (B) may be performed simultaneously. By firing the composition according to Embodiment 1, drying of the composition and carbonization of the organic matter may be performed.

[0080] In (A), after bringing the composition into a state of coated particles in which a solution containing an organic solvent and an organic matter (hereinafter referred to as "the solution part of the composition") covers at least a part of the surface of the particles of the active material, the coated particles may be dried to remove the solvent. For example, by filtering the composition according to Embodiment 1, the above-mentioned coated particles in which an appropriate amount of the solution part of the composition covers at least a part of the surface of the particles of the active material can be separated by filtration.

[0081] That is, the method for producing a coated active material according to Embodiment 2 is (A1) By filtering the composition according to Embodiment 1, obtaining coated particles in which the solution portion of the composition covers at least a part of the surface of the active material particles, (A2) drying the coated particles, and (B) carbonizing the organic matter by heat treatment may be included.

[0082] According to the above, a coated active material in which the surface of the active material is uniformly coated with an appropriate amount of organic matter can be manufactured. Thereby, an active material having high electron conductivity and capable of further improving the charge and discharge capacity of the battery can be manufactured. Further, by removing excess organic solvent (for example, monohydric alcohol) in advance, removal of the organic solvent by subsequent drying becomes easy.

[0083] (A1) and (A2) may be performed continuously, or another treatment may be performed between each step. (A2) and (B) may be performed continuously, or another treatment may be performed between each step. For example, after (A2) and before (B), the dried coated particles may be crushed. Alternatively, (A2) and (B) may be performed simultaneously.

[0084] (Embodiment 3) The method for manufacturing a battery according to Embodiment 3 is a method for manufacturing a battery including a first electrode, a second electrode, and an electrolyte layer disposed between the first electrode and the second electrode. In the formation of the first electrode in the method for manufacturing a battery according to Embodiment 3, (A) drying the composition according to Embodiment 1, and (B) carbonizing the organic matter by heat treatment are included.

[0085] According to the above, a battery including a coated active material having high electron conductivity can be manufactured. Therefore, the method for manufacturing a battery according to Embodiment 3 can manufacture a battery having high charge and discharge characteristics.

[0086] When the active material in the composition is a negative electrode active material, the first electrode becomes the negative electrode. When the active material in the composition is a positive electrode active material, the first electrode becomes the positive electrode.

[0087] The method for manufacturing a battery according to Embodiment 3 may include obtaining a coated active material by the steps including the above (A) and (B), and preparing an electrode material containing the coated active material.

[0088] The method for manufacturing a battery according to Embodiment 3 may form the first electrode by laminating the above electrode material on a current collector. Alternatively, the method for manufacturing a battery according to Embodiment 3 may form the electrolyte layer and then laminate the above electrode material on the electrolyte layer to form the first electrode. The electrolyte layer may be formed by laminating a solid electrolyte material.

[0089] The electrode material may be prepared by mixing the above coated active material and a solid electrolyte material. Examples of the solid electrolyte material are a sulfide solid electrolyte, an oxide solid electrolyte, a halide solid electrolyte, or an organic polymer solid electrolyte.

[0090] Examples of the sulfide solid electrolyte are Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, Li2S-GeS2, Li 3.25 Ge 0.25 P 0.75 S4, or Li 10 GeP2S 12 and so on.

[0091] Examples of the oxide solid electrolyte are (i) NASICON-type solid electrolytes such as LiTi2(PO4)3 or its element-substituted products, (ii) perovskite-type solid electrolytes such as (LaLi)TiO3, (iii) LISICON-type solid electrolytes such as Li 14 ZnGe4O 16 , Li4SiO4, LiGeO4 or its element-substituted products, (iv) garnet-type solid electrolytes such as Li7La3Zr2O 12 or its element-substituted products, or (v) Li3PO4 or its N-substituted derivative is used.

[0092] Examples of the halide solid electrolyte include Li2MgX’4, Li2FeX’4, Li(Al,Ga,In)X’4, Li3(Al,Ga,In)X’6, or LiX’.

[0093] Other examples of the halide solid electrolyte include Li p Me q a compound represented by YZ6. Here, p + m’q + 3r = 6 and r > 0 are satisfied. Me is at least one element selected from the group consisting of metal elements other than Li and Y and semi-metal elements. The value of m’ represents the valence of Me. Z is at least one selected from the group consisting of F, Cl, Br, and I. The “semi-metal elements” are B, Si, Ge, As, Sb, and Te. The “metal elements” are all elements included in Groups 1 to 12 of the periodic table (excluding hydrogen), and all elements included in Groups 13 to 16 of the periodic table (excluding B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se). In order to increase the ionic conductivity of the halide solid electrolyte, Me may be at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, and Nb.

[0094] Examples of the organic polymer solid electrolyte are a polymer compound and a compound of a lithium salt.

[0095] The polymer compound may have an ethylene oxide structure. Since a polymer compound having an ethylene oxide structure can contain a large amount of lithium salt, the ionic conductivity can be increased.

[0096] Examples of the lithium salt include LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), or LiC(SO2CF3)3. One lithium salt selected from these may be used alone. Alternatively, a mixture of two or more lithium salts selected from these may be used.

[0097] In addition to the above-described coated active material, the electrode material may contain a material capable of occluding and releasing metal ions (for example, lithium ions). When the active material in the composition is a negative electrode active material, the electrode material may further contain other negative electrode active materials.

[0098] Examples of the negative electrode active material include, in addition to the materials described in Embodiment 1, metal materials, carbon materials, oxides, nitrides, tin compounds, or silicon compounds. The metal material may be a single metal material or an alloy. Examples of the metal material include lithium metal or a lithium alloy. Examples of the carbon material include natural graphite, coke, carbon in the process of graphitization, carbon fiber, spherical carbon, artificial graphite, or amorphous carbon. From the viewpoint of capacity density, preferred examples of the negative electrode active material are silicon (i.e., Si), tin (i.e., Sn), silicon compounds, or tin compounds. By using an active material having a low average discharge voltage such as graphite as the negative electrode active material, the energy density of the battery can be improved.

[0099] The electrode material may further contain a conductive assistant in order to enhance the electron conductivity.

[0100] Examples of the conductive assistant include (i) graphites such as natural graphite or artificial graphite, (ii) carbon blacks such as acetylene black or ketjen black, (iii) conductive fibers such as carbon fiber or metal fiber, (iv) carbon fluoride (v) metal powders such as aluminum (vi) Conductive whiskers such as zinc oxide or potassium titanate, (vii) Conductive metal oxides such as titanium oxide, or (viii) Conductive polymer compounds such as polyaniline, polypyrrole, or polythiophene It is. For cost reduction, the conductive aids of (i) or (ii) above may be used.

[0101] For the purpose of facilitating the transfer of lithium ions and improving the output characteristics of the battery, the electrode material may contain a non-aqueous electrolyte, a gel electrolyte, or an ionic liquid.

[0102] The non-aqueous electrolyte contains a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent.

[0103] Examples of non-aqueous solvents are cyclic carbonate solvents, chain carbonate solvents, cyclic ether solvents, chain ether solvents, cyclic ester solvents, chain ester solvents, or fluorine solvents. Examples of cyclic carbonate solvents are ethylene carbonate, propylene carbonate, or butylene carbonate. Examples of chain carbonate solvents are dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate. Examples of cyclic ether solvents are tetrahydrofuran, 1,4-dioxane, or 1,3-dioxolane. Examples of chain ether solvents are 1,2-dimethoxyethane or 1,2-diethoxyethane. Examples of cyclic ester solvents are γ-butyrolactone. Examples of chain ester solvents are methyl acetate. Examples of fluorine solvents are fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoroethyl methyl carbonate, or fluorodimethylene carbonate. One non-aqueous solvent selected from these may be used alone. Alternatively, a mixture of two or more non-aqueous solvents selected from these may be used.

[0104] Examples of the lithium salt include LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), or LiC(SO2CF3)3. One kind of lithium salt selected from these may be used alone. Alternatively, a mixture of two or more lithium salts selected from these may be used.

[0105] The concentration of the lithium salt may be, for example, 0.5 mol / liter or more and 2 mol / liter or less.

[0106] As the gel electrolyte, a polymer material impregnated with a non-aqueous electrolyte can be used. Examples of the polymer material are polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, or a polymer having an ethylene oxide bond.

[0107] Examples of the cation contained in the ionic liquid are (i) aliphatic chain quaternary salts such as tetraalkylammonium or tetraalkylphosphonium, (ii) aliphatic cyclic ammonium such as pyrrolidinium, morpholinium, imidazolinium, tetrahydropyrimidinium, piperazinium, or piperidinium, or (iii) nitrogen-containing heteroaromatic cations such as pyridinium or imidazolium are.

[0108] Examples of the anion contained in the ionic liquid are PF6 - , BF4 - , SbF6 - , AsF6 - , SO3CF3 - , N(SO2CF3)2 - , N(SO2C2F5)2 - , N(SO2CF3)(SO2C4F9) - , or C(SO2CF3)3 - are.

[0109] The ionic liquid may contain a lithium salt.

[0110] The electrode material may contain a binder in order to enhance the adhesion between particles. As the binder, the materials described in Embodiment 1 can be used.

[0111] (Embodiment 4) Hereinafter, Embodiment 4 of the present disclosure will be described. Matters described in Embodiments 1 to 3 will be omitted as appropriate.

[0112] The battery according to Embodiment 4 includes a first electrode, a second electrode, and an electrolyte layer. The electrolyte layer is disposed between the first electrode and the second electrode. The first electrode includes the composition according to Embodiment 1. That is, the battery according to Embodiment 4 includes an organic solvent, an organic substance having a solubility in the organic solvent greater than 10 g / L, and an active material, and satisfies the following (A) or (B). (A) The solubility of the above organic substance in water is 10 g / L or less. (B) The pH of the aqueous solution of the above organic substance is 7 or more.

[0113] The battery according to Embodiment 4 has high charge and discharge characteristics.

[0114] When the composition contained in the first electrode contains a negative electrode active material, the first electrode is a negative electrode and the second electrode is a positive electrode. When the composition contained in the first electrode contains a positive electrode active material, the first electrode is a positive electrode and the second electrode is a negative electrode.

[0115] The second electrode may or may not contain the composition according to Embodiment 1. When the first electrode is a negative electrode and the second electrode is a positive electrode, the first electrode may contain the composition according to Embodiment 1 containing a negative electrode active material, and the second electrode may contain the composition according to Embodiment 1 containing a positive electrode active material.

[0116] The first electrode may further contain a conductive assistant.

[0117] The battery according to Embodiment 4 can be manufactured, for example, by the manufacturing method of the battery according to Embodiment 3.

[0118] Specific examples of the battery will be described below. Hereinafter, an example in which the first electrode is a negative electrode and the second electrode is a positive electrode will be described.

[0119] FIG. 1 shows a cross-sectional view of a battery 1000 according to Embodiment 4.

[0120] The battery 1000 includes a positive electrode 201, an electrolyte layer 202, and a negative electrode 203.

[0121] The positive electrode 201 contains positive electrode active material particles 204 and solid electrolyte particles 100.

[0122] The electrolyte layer 202 is disposed between the positive electrode 201 and the negative electrode 203.

[0123] The electrolyte layer 202 contains an electrolyte material (for example, a solid electrolyte material).

[0124] The negative electrode 203 includes the composition according to Embodiment 1. For example, the negative electrode 203 contains negative electrode active material particles 205, an organic solvent (not shown), an organic substance (not shown), and solid electrolyte particles 100, and the negative electrode active material particles 205 contain a coating active material. The organic substance has a solubility in the organic solvent greater than 10 g / L and satisfies the following (A) or (B). (A) The solubility of the organic substance in water is 10 g / L or less. (B) The pH of an aqueous solution of the organic substance is 7 or more.

[0125] The coating active material includes a negative electrode active material and a coating material that coats at least a part of the surface of the negative electrode active material. The coating active material is, for example, a coating active material manufactured by the manufacturing method according to Embodiment 2.

[0126] As the negative electrode active material, the active materials described above in Embodiment 1 can be used.

[0127] The coating material contains, for example, a conductive material. The conductive material may be obtained by carbonization of the above-mentioned organic substance. The coating material may contain the above-mentioned organic substance in addition to the conductive material.

[0128] The negative electrode active material particles 205 may be particles containing the above-mentioned coated active material as a main component. The particles containing the above-mentioned coated active material as a main component mean particles in which the component contained most in mass ratio is the above-mentioned coated active material. The negative electrode active material particles 205 may be particles consisting only of the above-mentioned coated active material.

[0129] The positive electrode 201 contains a material capable of occluding and releasing metal ions (for example, lithium ions). The material is, for example, a positive electrode active material (for example, positive electrode active material particles 204).

[0130] Examples of the positive electrode active material are lithium-containing transition metal oxides, transition metal fluorides, polyanion materials, fluorinated polyanion materials, transition metal sulfides, transition metal oxyfluorides, transition metal oxysulfides, or transition metal oxynitrides. Examples of the lithium-containing transition metal oxide are Li(Ni,Co,Al)O2, LiCoO2, or Li(Ni,Co,Mn)O2. From the viewpoint of the energy density of the battery, a preferred example of the positive electrode active material is Li(Ni,Co,Mn)O2. Li(Ni,Co,Mn)O2 can be charged and discharged at a potential of 4 V or more. In the present disclosure, "(A,B,C)" represents "at least one selected from the group consisting of A, B, and C". Here, A, B, and C all represent elements.

[0131] The positive electrode active material particles 204 may have a median diameter of 0.1 μm or more and 100 μm or less. When the positive electrode active material particles 204 have a median diameter of 0.1 μm or more, the positive electrode active material particles 204 and the solid electrolyte particles 100 can be well dispersed in the positive electrode 201. Thereby, the charge and discharge characteristics of the battery are improved. When the positive electrode active material particles 204 have a median diameter of 100 μm or less, the lithium diffusion rate in the positive electrode active material particles 204 is improved. Thereby, the battery can operate at high power.

[0132] The positive electrode active material particles 204 may have a median diameter larger than that of the solid electrolyte particles 100. Thereby, the positive electrode active material particles 204 and the solid electrolyte particles 100 can be well dispersed.

[0133] In order to increase the energy density and output of the battery, in the positive electrode 201, the ratio of the volume of the positive electrode active material particles 204 to the total volume of the positive electrode active material particles 204 and the solid electrolyte particles 100 may be 0.30 or more and 0.95 or less.

[0134] In order to increase the energy density and output of the battery, the positive electrode 201 may have a thickness of 10 μm or more and 500 μm or less.

[0135] The electrolyte layer 202 contains an electrolyte material. The electrolyte material is, for example, a solid electrolyte material. The electrolyte layer 202 may be a solid electrolyte layer.

[0136] The electrolyte layer 202 may be composed of only a solid electrolyte material. Examples of the solid electrolyte material include the materials described above in Embodiment 3.

[0137] The electrolyte layer 202 may have a thickness of 1 μm or more and 100 μm or less. When the electrolyte layer 202 has a thickness of 1 μm or more, it is less likely that the positive electrode 201 and the negative electrode 203 are short-circuited. When the electrolyte layer 202 has a thickness of 100 μm or less, the battery can operate at high output.

[0138] In addition to the above coating active material, the negative electrode 203 may contain a material capable of occluding and releasing metal ions (for example, lithium ions). The material is, for example, a negative electrode active material.

[0139] As the negative electrode active material, for example, the negative electrode active materials described above in Embodiment 3 can be used.

[0140] The negative electrode active material particles 205 may have a median diameter of 0.1 μm or more and 100 μm or less. When the negative electrode active material particles 205 have a median diameter of 0.1 μm or more, in the negative electrode 203, the dispersion state of the negative electrode active material particles 205 and the solid electrolyte particles 100 becomes good. Thereby, the charge and discharge characteristics of the battery are improved. When the negative electrode active material particles 205 have a median diameter of 100 μm or less, the lithium diffusion rate in the negative electrode active material particles 205 is improved. Thereby, the battery can operate at high power.

[0141] The negative electrode active material particles 205 may have a median diameter larger than that of the solid electrolyte particles 100. Thereby, in the negative electrode 203, the dispersion state of the negative electrode active material particles 205 and the solid electrolyte particles 100 becomes good.

[0142] In order to increase the energy density and output of the battery, in the negative electrode 203, the ratio of the volume of the negative electrode active material particles 205 to the total volume of the negative electrode active material particles 205 and the solid electrolyte particles 100 may be 0.30 or more and 0.95 or less.

[0143] In order to increase the energy density and output of the battery, the negative electrode 203 may have a thickness of 10 μm or more and 500 μm or less.

[0144] For the solid electrolyte particles 100, for example, the solid electrolyte material described above in Embodiment 3 can be used.

[0145] At least one selected from the group consisting of the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a non-aqueous electrolyte, a gel electrolyte, or an ionic liquid for the purpose of facilitating the transfer of lithium ions and improving the output characteristics of the battery. For the non-aqueous electrolyte, the gel electrolyte, or the ionic liquid, for example, the materials described above in Embodiment 3 can be used.

[0146] At least one selected from the group consisting of the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a binder in order to enhance the adhesion between particles. As the binder, for example, the binder described in Embodiment 3 can be used.

[0147] Examples of the shape of the battery according to Embodiment 4 are coin type, cylindrical type, rectangular type, sheet type, button type, flat type, or laminated type.

[0148] The battery according to Embodiment 4 may be manufactured, for example, by preparing materials for forming a positive electrode, materials for forming an electrolyte layer, and materials for forming a negative electrode, and producing a laminate in which the positive electrode, the electrolyte layer, and the negative electrode are arranged in this order by a known method. At this time, at least one selected from the group consisting of the material for forming the positive electrode and the material for forming the negative electrode contains the composition according to Embodiment 1.

[0149] (Other Embodiments) (Supplementary Note) According to the description of the above embodiments, the following technologies are disclosed.

[0150] (Technology 1) An organic solvent, An organic substance, An active material, comprising, the solubility of the organic substance in the organic solvent is greater than 10 g / L, a composition satisfying the following (A) or (B). (A) The solubility of the organic substance in water is 10 g / L or less. (B) The pH of the aqueous solution of the organic substance is 7 or more.

[0151] According to this configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0152] (Technology 2) The composition according to Technology 1, wherein the organic solvent contains a monohydric alcohol. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0153] (Technology 3) The composition according to Technology 1 or 2, wherein the organic solvent contains at least one selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, and water. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0154] (Technology 4) The composition according to any one of Technologies 1 to 3, wherein the organic solvent contains ethanol. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0155] (Technology 5) The composition according to any one of Technologies 1 to 4, wherein the organic substance has a hydroxy group. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0156] (Technology 6) The composition according to any one of Technologies 1 to 5, wherein the organic substance has a benzene ring. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0157] (Technology 7) The composition according to any one of Technologies 1 to 6, wherein the organic substance contains phenols. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0158] (Technology 8) The composition according to Technology 7, wherein the phenols are bisphenols. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0159] (Technology 9) The composition according to any one of Technologies 1 to 8, wherein the organic substance contains sugar. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0160] (Technology 10) The composition according to Technique 9, wherein the sugar contains at least one selected from the group consisting of fructose, mannose, sorbitol, and xylitol. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0161] (Technique 11) The composition according to any one of Techniques 1 to 10, wherein the organic substance contains a polymer compound. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0162] (Technique 12) The composition according to any one of Techniques 1 to 11, wherein the active material contains V element. According to such a configuration, an active material capable of improving the charge and discharge capacity of the battery can be realized.

[0163] (Technique 13) The active material is a compound represented by the composition formula (1), Li 3+x+a V 1-x M x O 4+a / 2 ··· Formula (1) Here, M is at least one selected from the group consisting of tetravalent metal elements and tetravalent metalloid elements, The composition formula (1) satisfies 0 ≦ a < 1 and 0 ≦ x < 1, The composition according to any one of Techniques 1 to 12. The compound represented by the composition formula (1) is suitable for improving the charge and discharge characteristics of the battery. Therefore, according to such a configuration, the charge and discharge capacity of the battery can be further improved.

[0164] (Technique 14) The composition according to Technique 13, wherein the composition formula (1) satisfies 0 ≦ x ≦ 0.15. According to such a configuration, the charge and discharge capacity of the battery can be further improved.

[0165] (Technique 15) The composition according to Technique 13 or 14, wherein M contains Ti. According to such a configuration, the charge and discharge capacity of the battery can be further improved.

[0166] (Technology 16) (A) Drying the composition according to any one of Technologies 1 to 15 comprising A method for manufacturing a coating active material.

[0167] According to such a configuration, a coating active material capable of improving the charge and discharge capacity of a battery can be provided.

[0168] (Technology 17) (B) Carbonizing the organic matter by heat treatment The method for manufacturing a coating active material according to Technology 16, further comprising this. According to such a configuration, a coating active material capable of improving the charge and discharge capacity of a battery can be provided.

[0169] (Technology 18) A first electrode, A second electrode, An electrolyte layer disposed between the first electrode and the second electrode, A method for manufacturing a battery comprising The manufacturing method includes In forming the first electrode, (A) Drying the composition according to any one of Technologies 1 to 15, and (B) Carbonizing the organic matter by heat treatment comprising A method for manufacturing a battery.

[0170] According to such a configuration, a battery having excellent charge and discharge characteristics can be provided.

[0171] (Technology 19) A first electrode, A second electrode, An electrolyte layer disposed between the first electrode and the second electrode, comprising The first electrode contains the composition according to any one of claims 1 to 15 A battery.

[0172] According to such a configuration, excellent charge and discharge characteristics can be obtained.

[0173] (Technology 20) The first electrode further includes a conductive assistant, and is the battery described in Technology 19. According to such a configuration, the first electrode has high electron conductivity, and as a result, the battery has excellent charge and discharge characteristics.

Examples

[0174] Hereinafter, the details of the present disclosure will be described using examples and comparative examples.

[0175] ≪Example 1≫ [Preparation of Coated Active Material] 13.7 g of bisphenol A was dissolved in 80 mL of ethanol to prepare a 0.75 mol / L solution. At 25°C, bisphenol A was completely dissolved. The solubility of bisphenol A in water is 10 g / L or less. 1 g of the powder of the negative electrode active material Li3VO4 (hereinafter referred to as LVO) was immersed in the prepared solution to obtain a slurry. After the slurry was stirred for about 30 minutes, filtration was performed using a membrane filter with a pore size of 1 μm. By filtration, LVO powder with the above solution adhering to its surface was obtained. The obtained LVO powder was dried at 80°C for 2 hours under atmospheric pressure and then crushed. Next, the crushed LVO powder was calcined at 600°C for 24 hours in a vacuum atmosphere of 0.2 Pa or less to carbonize bisphenol A present on the surface of the LVO powder. The calcined product was crushed in a mortar to obtain a coated active material as the active material sample of Example 1.

[0176] [Measurement of Electron Conductivity] Figure 2 shows a schematic diagram of the compression molding die 300 used to evaluate the electron conductivity of the active material.

[0177] The compression molding die 300 included a punch upper part 301, a frame type 302, and a punch lower part 303. The frame type 302 was formed of insulating polycarbonate. The punch upper part 301 and the punch lower part 303 were formed of electron-conductive stainless steel.

[0178] Using the pressure forming die 300 shown in FIG. 2, the electronic conductivity of the coating active material of Example 1 was measured by the following method.

[0179] In a dry argon atmosphere, the coating active material of Example 1 (i.e., sample 101 in FIG. 2) was filled inside the pressure forming die 300. Inside the pressure forming die 300, a pressure of 720 MPa was applied to the coating active material of Example 1 using the upper punch 301 and the lower punch 303.

[0180] While the pressure was applied, the upper punch 301 and the lower punch 303 were connected to a potentiostat (Biologic, VSP-300) equipped with a frequency response analyzer. The upper punch 301 was connected to the working electrode and the terminal for potential measurement. The lower punch 303 was connected to the counter electrode and the reference electrode. The electronic conductivity was measured at room temperature by the DC measurement method.

[0181] Using the resistance value, the electronic conductivity was calculated based on the following formula (2). σ=(R E ×S / t) -1 ···(2) Here, σ represents the electronic conductivity. S represents the contact area of sample 101 with the upper punch 301 (equal to the cross-sectional area of the hollow part of the frame type 302 in FIG. 2). R E represents the resistance value of the coating active material in the DC measurement method. t represents the thickness of the coating active material to which the pressure is applied (equal to the thickness of the layer formed from sample 101 in FIG. 2).

[0182] The electronic conductivity of the coating active material of Example 1 measured at 25°C was 8.05×10 -2 S / cm.

[0183] [Fabrication of Sulfide Solid Electrolyte] In an argon glove box with a dew point below -60°C, the raw material powders, Li2S and P2S5, were weighed so that the molar ratio was Li2S:P2S5 = 0.750:0.250. These raw material powders were pulverized and mixed in an agate mortar. In this way, a mixture was obtained. Then, using a planetary ball mill (manufactured by Fritsch, model P-7), the mixture was milled for 12 hours under the conditions of 500 rpm. Thereby, a glassy solid electrolyte was obtained. Next, in a glove box with a dew point below -60°C, using a firing furnace, the glassy solid electrolyte was fired at 270°C for 2 hours. In this way, as a sulfide solid electrolyte, a powder of a glass-ceramic solid electrolyte, Li2S-P2S5 (hereinafter referred to as LPS), was obtained.

[0184] [Fabrication of the negative electrode material] In an argon glove box with a dew point below -60°C, the coating active material of Example 1 and LPS were weighed so that the volume ratio of LVO and LPS was 0.650:0.350. By mixing these in an agate mortar, the negative electrode material of Example 1 was fabricated.

[0185] [Fabrication of the secondary battery] LPS (94.0 mg) was put into an insulating cylinder having an inner diameter of 9.50 mm, and a pressure of 80 MPa was applied to form a solid electrolyte layer.

[0186] Next, the negative electrode material of Example 1 (6.27 mg) was laminated on the solid electrolyte layer formed from LPS to obtain a laminate. A pressure of 720 MPa was applied to this laminate to form a negative electrode.

[0187] Next, a metallic Li foil (thickness 300 μm) was laminated on the solid electrolyte layer formed from LPS to obtain a laminate. A pressure of 80.0 MPa was applied to this laminate to form a positive electrode.

[0188] Current collectors made of stainless steel were arranged on the positive and negative electrodes, and current collecting leads were attached to the current collectors.

[0189] Finally, using an insulating ferrule, the inside of the insulating cylinder was blocked from the outside air atmosphere, and the inside of the cylinder was sealed. In this way, the battery of Example 1 was obtained.

[0190] ≪Example 2≫ [Preparation of Coated Active Material] 1.0 g of fructose was dissolved in 80 mL of ethanol to prepare a 0.070 mol / L solution. The coated active material of Example 2 was obtained in the same manner as in Example 1, except that 1 g of LVO powder was immersed in the prepared solution to obtain a slurry. Note that at 25 °C, fructose was completely dissolved.

[0191] [Measurement of Electronic Conductivity] The electronic conductivity of the coated active material of Example 2 was measured in the same manner as in Example 1. The electronic conductivity of the coated active material of Example 2 measured at 25 °C was 2.83×10 -3 S / cm.

[0192] [Preparation of Negative Electrode Material] The negative electrode material of Example 2 was obtained in the same manner as in Example 1, except that the coated active material of Example 2 was used.

[0193] [Preparation of Secondary Battery] The battery of Example 2 was obtained in the same manner as in Example 1, except that the negative electrode material of Example 2 was used.

[0194] ≪Example 3≫ Instead of 1.0 g of fructose, 1.0 g of mannose was dissolved in 80 mL of ethanol to prepare a 0.070 mol / L solution. The coated active material of Example 3 was obtained in the same manner as in Example 1, except that 1 g of LVO powder was immersed in the prepared solution to obtain a slurry. Note that at 25 °C, mannose was completely dissolved.

[0195] [Measurement of Electronic Conductivity] The electronic conductivity of the coated active material of Example 3 was measured in the same manner as in Example 1. The electronic conductivity of the coated active material of Example 3 measured at 25 °C was 1.02×10 -2It was S / cm.

[0196] [Fabrication of the negative electrode material] A negative electrode material of Example 3 was obtained in the same manner as in Example 1, except that the coating active material of Example 3 was used.

[0197] [Fabrication of the secondary battery] A battery of Example 3 was obtained in the same manner as in Example 1, except that the negative electrode material of Example 3 was used.

[0198] <<Comparative Example 1>> 0.68 g of benzoic acid was dissolved in 80 mL of ethanol to prepare a 0.70 mol / L solution. By immersing 1 g of LVO powder in the prepared solution, a slurry was obtained. When the slurry was stirred for about 30 minutes, a black precipitate was formed. Therefore, the LVO powder could not be recovered by filtration, and the coating active material could not be obtained.

[0199] <<Comparative Example 2>> 0.53 g of phenol was dissolved in 80 mL of ethanol to prepare a 0.70 mol / L solution. By immersing 1 g of LVO powder in the prepared solution, a slurry was obtained. When the slurry was stirred for about 30 minutes, a black precipitate was formed. Therefore, the LVO powder could not be recovered by filtration, and the coating active material could not be obtained.

[0200] <<Comparative Example 3>> 0.53 g of catechol was dissolved in 80 mL of ethanol to prepare a 0.70 mol / L solution. By immersing 1 g of LVO powder in the prepared solution, a slurry was obtained. When the slurry was stirred for about 30 minutes, a black precipitate was formed. Therefore, the LVO powder could not be recovered by filtration, and the coating active material could not be obtained.

[0201] <<Comparative Example 4>> 0.62 g of resorcinol was dissolved in 80 mL of ethanol to prepare a 0.70 mol / L solution. 1 g of LVO powder was immersed in the prepared solution to obtain a slurry. When the slurry was stirred for about 30 minutes, a black precipitate formed. Therefore, the LVO powder could not be recovered by filtration, and the coated active material could not be obtained.

[0202] <<Comparative Example 5>> 0.62 g of hydroquinone was dissolved in 80 mL of ethanol to prepare a 0.70 mol / L solution. 1 g of LVO powder was immersed in the prepared solution to obtain a slurry. When the slurry was stirred for about 30 minutes, a black precipitate formed. Therefore, the LVO powder could not be recovered by filtration, and the coated active material could not be obtained.

[0203] <<Comparative Example 6>> 1.08 g of citric acid was dissolved in 80 mL of ethanol to prepare a 0.70 mol / L solution. 1 g of LVO powder was immersed in the prepared solution to obtain a slurry. When the slurry was stirred for about 30 minutes, a black precipitate formed. Therefore, the LVO powder could not be recovered by filtration, and the coated active material could not be obtained.

[0204] <<Comparative Example 7>> A slurry was obtained by immersing 1 g of LVO powder in 80 mL of ethanol. After the slurry was stirred for about 30 minutes, the LVO powder was obtained by filtration using a membrane filter with a pore size of 1 μm. The obtained LVO powder was dried at 80 °C for 2 hours under atmospheric pressure and then crushed. Next, the crushed LVO powder was calcined at 600 °C for 24 hours in a vacuum atmosphere of 0.2 Pa or less. The calcined product was crushed in a mortar to obtain the active material sample of Comparative Example 7.

[0205] [Measurement of Electronic Conductivity] The electronic conductivity of the active material sample of Comparative Example 7 was measured in the same manner as in Example 1. The electronic conductivity of the active material sample of Comparative Example 7 was 1.0×10 -10 S / cm or less and could not be measured.

[0206] [Fabrication of negative electrode material] A negative electrode material of Comparative Example 7 was obtained in the same manner as in Example 1, except that the active material sample of Comparative Example 7 was used.

[0207] [Fabrication of secondary battery] A battery of Comparative Example 7 was obtained in the same manner as in Example 1, except that the negative electrode material of Comparative Example 7 was used.

[0208] <<Comparative Example 8>> 1.0 g of mannose was dissolved in 80 mL of water to prepare a 0.070 mol / L solution. 1 g of LVO powder was immersed in the solution to obtain a slurry. After the slurry was stirred for about 30 minutes, the solution was filtered using a membrane filter with a pore size of 1 μm. Since all of the LVO had dissolved in water, the active material sample could not be separated by filtration.

[0209] <<Comparative Example 9>> 1.0 g of fructose was dissolved in 80 mL of water to prepare a 0.070 mol / L solution. 1 g of LVO powder was immersed in the solution to obtain a slurry. After the slurry was stirred for about 30 minutes, the solution was filtered using a membrane filter with a pore size of 1 μm. Since all of the LVO had dissolved in water, the active material sample could not be separated by filtration.

[0210] [Charge-discharge measurement] The initial charge-discharge characteristics of the batteries of Examples 1 to 3 and Comparative Example 7 were measured by the following method. The fabricated battery is a cell for charge-discharge test and corresponds to the half-cell of the negative electrode. Therefore, in the examples, charging means a state in which current flows in the direction in which lithium ions move from metallic Li (i.e., the above positive electrode) to the negative electrode, and discharging means a state in which current flows in the direction from the negative electrode to metallic Li (i.e., the above positive electrode). That is, the direction in which the potential of the half-cell decreases is called charging, and the direction in which the potential increases is called discharging.

[0211] The battery was placed in a constant temperature bath at 25°C.

[0212] 78 μA / cm 2 At a current density of, the battery was charged until the negative electrode reached a voltage of 0.30 V relative to the positive electrode. This current density corresponds to a 0.05 C rate (20-hour rate) relative to the theoretical capacity of the battery.

[0213] Next, at a current density of 78 μA / cm 2 the battery was discharged until the negative electrode reached a voltage of 2.50 V relative to the positive electrode. This current density corresponds to a 0.05 C rate (20-hour rate) relative to the theoretical capacity of the battery.

[0214] As a result of the charge-discharge measurement, the battery according to Example 1 had an initial charge capacity of 1.49 mAh. FIG. 3 is a graph showing the initial charge-discharge characteristics of the battery of Example 1.

[0215] The battery according to Example 2 had an initial charge capacity of 1.14 mAh.

[0216] The battery according to Example 3 had an initial charge capacity of 1.32 mAh.

[0217] The battery according to Comparative Example 7 had an initial charge capacity of 0.100 mAh.

[0218] The various measurement results of Examples 1 to 3 and Comparative Examples 1 to 9 are shown in Table 1. The item "LVO reactivity" in Table 1 indicates the presence or absence of the reaction of LVO judged from the color change of LVO. In Examples 1 to 3 and Comparative Example 7, LVO did not change color and remained white. In Comparative Examples 1 to 6, LVO changed from yellow to black, and black precipitate was formed. The item "pH" in Table 1 shows the pH of a 0.1 mol / L aqueous solution in which the used organic substance was dissolved in water.

[0219]

Table 1

[0220] ≪Discussion≫ In Examples 1 to 3, a coating active material having high electronic conductivity and a battery having improved charge capacity were obtained. The batteries of Examples 1 to 3 showed higher charge capacity than the battery of Comparative Example 7.

[0221] In Comparative Examples 1 to 6, LVO reacted to form a black precipitate and the powder could not be recovered. This is presumably because when an organic substance capable of supplying protons was used, lithium in LVO was exchanged with protons in the organic substance to form a lithium salt. In Example 1 using bisphenol A which is hardly soluble in water as the organic substance, a coating active material having high electronic conductivity was obtained. This is presumably because the release of protons from the organic substance was suppressed and LVO did not react. In Examples 2 and 3 using organic substances with an aqueous solution pH of 7 or higher, coating active materials having high electronic conductivity were also obtained. This is also presumably because the release of protons from the organic substance was suppressed and LVO did not react.

[0222] In Comparative Examples 8 to 9, since water was used instead of an organic solvent, LVO completely dissolved in water and a coating active material could not be produced. This is presumably because due to the high polarity of the solvent, LVO dissolved and decomposed, and the structure could not be maintained.

Industrial Applicability

[0223] The battery of the present disclosure can be used, for example, as an all-solid-state lithium secondary battery or the like.

Explanation of Signs

[0224] 100 Solid electrolyte particles 201 Positive electrode 202 Electrolyte layer 203 Negative electrode 204 Positive electrode active material particles 205 Negative electrode active material particles 1000 Battery 300 Press molding die 301 Upper punch 302 Frame type 303 Lower punch 101 Sample

Claims

1. An organic solvent; Organic matter and An active material; Including, the solubility of the organic substance in the organic solvent is greater than 10 g / L; The following (A) or (B) is satisfied: composition. (A) The solubility of the organic substance in water is 10 g / L or less. (B) The pH of the aqueous solution of the organic substance is 7 or higher.

2. The organic solvent includes a monohydric alcohol. The composition of claim 1.

3. The organic solvent comprises at least one selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, and water; The composition of claim 1.

4. The organic solvent comprises ethanol. The composition of claim 3.

5. The organic substance has a hydroxy group. The composition of claim 1.

6. The organic substance has a benzene ring. The composition of claim 1.

7. The organic matter includes a phenol. The composition of claim 6.

8. The phenols are bisphenols. The composition of claim 7.

9. The organic matter comprises sugar; The composition of claim 1.

10. The sugar comprises at least one selected from the group consisting of fructose, mannose, sorbitol, and xylitol; The composition of claim 9.

11. The organic matter includes a polymer compound. The composition of claim 1.

12. The active material contains a V element. The composition of claim 1.

13. The active material is a compound represented by composition formula (1), Li 3+x+a V 1-x M x O 4+a / 2 ... Formula (1) Where: M is at least one selected from the group consisting of tetravalent metal elements and tetravalent metalloid elements, The composition formula (1) satisfies 0≦a<1 and 0≦x<1. The composition of claim 1.

14. The composition formula (1) satisfies 0≦x≦0.15, The composition of claim 13.

15. The M includes Ti. The composition of claim 13.

16. (A) drying the composition according to any one of claims 1 to 15; Including, A method for producing a coated active material.

17. (B) carbonizing the organic matter by heat treatment; Further comprising: The method for producing the coated active material according to claim 16 .

18. A first electrode; A second electrode; an electrolyte layer disposed between the first electrode and the second electrode; A method for manufacturing a battery comprising: The manufacturing method includes: In forming the first electrode, (A) drying the composition according to any one of claims 1 to 15; and (B) carbonizing the organic matter by heat treatment; Including, How batteries are manufactured.

19. A first electrode; A second electrode; an electrolyte layer disposed between the first electrode and the second electrode; Equipped with The first electrode comprises a composition according to any one of claims 1 to 15. battery.

20. The first electrode further includes a conductive assistant.

20. The battery of claim 19.

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