Non-aqueous electrolyte and electrochemical device

Abstract

The present invention provides a non-aqueous electrolyte containing a metal organic structure having a higher adsorption amount of carbon dioxide. The present invention relates to a non-aqueous electrolyte containing a metal organic structure containing an azole-based organic molecule capable of having a hydrophobic group and a metal atom, and having a specific surface area to pore volume ratio of 10 or less.

Description

Technical Field

[0001] This invention relates to non-aqueous electrolytes and electrochemical devices. Background Technology

[0002] Conventional electrochemical devices such as lithium-ion secondary batteries and double-layer capacitors have structures that encapsulate the positive electrode, negative electrode, separator, and non-aqueous electrolyte within an outer casing (e.g., Non-Patent Document 1). In such electrochemical devices, the non-aqueous electrolyte oxidizes during use, producing gases such as carbon dioxide. Therefore, it is known that internal pressure rises, causing expansion and, depending on the situation, rupture, raising safety and reliability concerns.

[0003] Therefore, in Patent Document 1, in order to prevent the expansion of lithium-ion batteries and improve safety, an attempt was made to configure zeolite as an adsorbent material separately from the electrolyte in an airtight container.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-5496

[0007] Non-patent literature

[0008] Non-patent literature 1: Ohsaki et al. / Journal of Power Sources 146(2005)97-100 Summary of the Invention

[0009] The technical problem that the invention aims to solve

[0010] However, the inventors of this application have discovered the following new problems arising from the prior art.

[0011] In the technology of Patent Document 1, porous materials such as zeolites generally have high water absorption, so it is impossible to avoid the adsorption of water during or before manufacturing. If mixed with the electrolyte, the Li salt decomposes, causing the properties to deteriorate. Therefore, although it is configured separately from the electrolyte, the battery size increases, and the structure becomes more complex and costly.

[0012] Therefore, the inventors of this application attempted to use metal-organic structures to adsorb carbon dioxide from non-aqueous electrolytes, but further discovered a new problem: the adsorption capacity could not be fully achieved.

[0013] The purpose of this invention is to provide a non-aqueous electrolyte containing a metal-organic structure with a higher adsorption capacity for carbon dioxide, and an electrochemical device containing the non-aqueous electrolyte.

[0014] Another object of the present invention is to provide an electrochemical device that, although having a simple structure, can more effectively prevent expansion caused by the generation of carbon dioxide gas.

[0015] Technical solutions for solving technical problems

[0016] This invention relates to non-aqueous electrolytes and electrochemical devices comprising the non-aqueous electrolyte, wherein the non-aqueous electrolyte comprises a metal-organic structure containing azole-based organic molecules capable of having hydrophobic groups and metal atoms, and the ratio of specific surface area to pore volume is [missing information]. The above and the following.

[0017] The effects of the invention

[0018] The non-aqueous electrolyte of the present invention contains a metal-organic structure that adsorbs carbon dioxide at a sufficiently high level. Therefore, the electrochemical device incorporating the non-aqueous electrolyte of the present invention, while having a simple structure, can more effectively prevent expansion caused by the generation of carbon dioxide gas. Specifically, in the electrochemical device incorporating the non-aqueous electrolyte of the present invention, because the metal-organic structure contained in the non-aqueous electrolyte has a sufficiently high adsorption capacity for carbon dioxide, expansion prevention of the electrochemical device can be achieved with a simple structure by mixing it into the non-aqueous electrolyte. More specifically, the metal-organic structure can adsorb gases generated from the electrochemical device, enabling a safe and reliable electrochemical device with a simple structure. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating the crystalline structure of the metal-organic structure contained in the non-aqueous electrolyte of the present invention.

[0020] Figure 2 This is a schematic cross-sectional view of a secondary battery, which is an example of the electrochemical device of the present invention.

[0021] Figure 3 This is a schematic cross-sectional view of a capacitor, which is an example of the electrochemical device of the present invention.

[0022] Figure 4 This is a schematic diagram illustrating the method for determining the amount of carbon dioxide adsorbed in the examples. Detailed Implementation

[0023] [Non-aqueous electrolyte]

[0024] The non-aqueous electrolyte of the present invention is the electrolyte contained in the electrochemical device described later. A non-aqueous electrolyte refers to an electrolyte in which the medium for electrolyte ion movement does not contain water, that is, an electrolyte that uses only organic solvents as the medium.

[0025] The non-aqueous electrolyte of this invention contains a specific metal-organic structure (i.e., MOF: Metal-Organic Framework). For example Figure 1 As shown, a metal-organic structure is a crystalline complex formed by cross-linking an organic molecule OM with metal atoms (especially metal ions) MA as ligands. It is a porous body based on the coordination bonds between the organic molecule and the metal atoms (especially metal ions). In this specification, the various elements in the accompanying drawings are shown schematically and illustratively only for understanding the invention, and their appearance and size ratios may differ from the actual objects. Unless otherwise stated, the terms "up-down direction," "left-right direction," and "in-out direction" used directly or indirectly in this specification correspond to the directions shown in the figures, respectively. Unless otherwise stated, the same reference numerals or symbols, except for differences in shape, indicate the same parts or have the same meaning.

[0026] In this invention, the metal-organic structure contained in the non-aqueous electrolyte is a metal-organic structure containing azole organic molecules capable of having hydrophobic groups and metal atoms, and the ratio of specific surface area to pore volume is within a specific range.

[0027] In detail, the ratio of the specific surface area to the pore volume of a metal-organic structure is: The above and From the perspective of further increasing the amount of carbon dioxide adsorbed in metal-organic structures, the following is preferred. The above and The following is preferred. The above and The following describes how metal-organic structures, by achieving a specific surface area to pore volume ratio that allows for selective and more efficient adsorption and capture of carbon dioxide without hindering the adsorption of carbon dioxide by substances contained in non-aqueous electrolytes. If the specific surface area to pore volume ratio is too small, the pores are uneven, and therefore, if solvent molecules and / or electrolyte salt molecules enter the pores, carbon dioxide cannot be sufficiently adsorbed. If the specific surface area to pore volume ratio is too large, the pores are uneven, and although carbon dioxide can be adsorbed even if solvent molecules and / or electrolyte salt molecules enter the pores, the adsorbed carbon dioxide is free, resulting in insufficient adsorption and capture of carbon dioxide.

[0028] The ratio of specific surface area to pore volume is a parameter indicating the roughness or unevenness of pores. A larger ratio indicates a more rough or uneven pore. Conversely, a smaller ratio indicates a less rough or uneven pore.

[0029] In this specification, the ratio of specific surface area to pore volume is expressed as specific surface area (m²). 2 / g) divided by pore volume (cm³) 3 The value obtained by converting / g) into The value obtained from the unit.

[0030] Specific surface area and pore volume were determined using structural data based on the unit crystal structure of metal-organic structures, with the probe molecule diameter set as... The Connolly surface area (specific surface area) and pore volume are calculated. Here, the Connolly surface area refers to the calculated probe molecule diameter. The value is calculated by summing the areas of contact between the sphere and each atom (a sphere of van der Waals radius) in the metal-organic structure. The pore diameter is similarly calculated by considering the diameter of the probe molecule. The specific surface area and pore volume are determined by the volume of the interstices between the atoms (as van der Waals spheres) in a metal-organic structure. While specific surface area and pore volume can be experimentally measured using methods such as the BET method, the results are inaccurate due to variations in cleaning and measurement conditions. Therefore, by using the method calculated from the crystal structure described above, the specific surface area and pore volume of metal-organic structures can be determined more accurately.

[0031] The unit crystal structure of metal-organic structures can be detected, for example, by obtaining crystal diffraction images using a single crystal measuring device manufactured by Rigaku Corporation, and by analyzing the obtained diffraction images using the analysis software "Yadokari XG2009".

[0032] The setting conditions for the above measuring device are as follows:

[0033] VariMax, a single-crystal structure analysis device for extremely small crystals;

[0034] MoKα rays

[0035] Irradiation time: 4 seconds;

[0036] d = 45 mm;

[0037] 2θ = -20;

[0038] Temperature = -180℃.

[0039] The specific surface area of ​​metal-organic structures is not particularly limited, for example, it can be 1700 m². 2 / g or more and 2500m 2 From the viewpoint of further increasing the carbon dioxide adsorption capacity in metal-organic structures, a concentration of 1800 mg / g or less is preferred. 2 / g or more and 2400m 2 / g or less, more preferably 1950m 2 / g or more and 2350m 2 / g or less or 1950m 2 / g or more and 2300m 2 / g or less, more preferably 2200m 2 / g or more and 2350m 2 / g or less or 2200m 2 / g or more and 2300m 2 / g or less.

[0040] The pore volume of metal-organic structures is not particularly limited, for example, it can be 0.20 cm³. 3 / g or more and 0.50cm 3 From the viewpoint of further increasing the carbon dioxide adsorption capacity in the metal-organic structure, a value of 0.25 cm³ / g or less is preferred. 3 / g or more and 0.40cm 3 / g or less, more preferably 0.28cm 3 / g or more and 0.35cm 3 / g or less, more preferably 0.31cm 3 / g or more and 0.35cm 3 / g or less.

[0041] Azole-based organic molecules capable of possessing hydrophobic groups can be unsubstituent azole-based organic molecules, azole-based organic molecules with substituents but only hydrophobic groups as substituents, or mixtures thereof. As organic molecules constituting metal-organic structures, azole-based organic molecules do not possess hydrophobic groups (or hydrophilic groups) such as amino, imino, carboxyl, carboxyl (i.e., carboxylic ester), hydroxyl, ketone, or aldehyde groups. Metal-organic structures containing azole-based organic molecules capable of possessing hydrophobic groups can exhibit both water resistance and adsorption capacity for gases (especially carbon dioxide) generated by electrochemical devices. Therefore, lithium salt decomposition can be more effectively prevented, and expansion can be more effectively prevented by adsorbing gases (especially carbon dioxide) generated from electrochemical devices. Specifically, based on the porosity of this metal-organic structure, it can adsorb gases (especially carbon dioxide) generated from electrochemical devices, thus achieving an anti-expansion effect. Meanwhile, because this metal-organic structure is resistant to water absorption, it will not cause salt decomposition even when mixed into the electrolyte, achieving an anti-swelling effect with a simple structure. As a result, a safe and reliable electrochemical device can be realized with a simple structure. For example, porous materials such as zeolites readily adsorb water in addition to carbon dioxide gas. Therefore, if a non-aqueous electrolyte replaces the aforementioned metal-organic structure and contains porous materials such as zeolites, the lithium salt decomposes due to the reaction with adsorbed water, producing hydrofluoric acid, and deteriorating components such as electrodes. Therefore, the reliability of electrochemical devices such as lithium-ion batteries or double-layer capacitors is reduced. Furthermore, for example, if the organic molecules constituting the metal-organic structure have water-absorbing (or hydrophilic) groups, these organic molecules adsorb water. Therefore, similar to the case of using porous materials such as zeolites, the lithium salt decomposes due to the reaction with adsorbed water, and components such as electrodes deteriorate, reducing the reliability of the electrochemical device.

[0042] The azole-based organic molecules constituting the metal-organic structure are one or more organic molecules selected from the group consisting of imidazole, benzimidazole, triazole, and purine. From the viewpoint of further increasing the carbon dioxide adsorption capacity of the metal-organic structure, it is preferable to select one or more organic molecules selected from the group consisting of imidazole, benzimidazole, and purine, and more preferably to select one or more (especially two) organic molecules selected from the group consisting of imidazole and benzimidazole.

[0043] The hydrophobic groups that azole-based organic molecules can possess are one or more substituents selected from the group consisting of alkyl, halogen, nitro, phenyl, pyridyl, and cyano groups. From the viewpoint of further increasing the carbon dioxide adsorption capacity of organometallic structures, azole-based organic molecules constituting organometallic structures preferably possess hydrophobic groups.

[0044] Alkyl groups are, for example, alkyl groups having 1 or more but 5 or fewer carbon atoms (especially 1 or more but 3 or fewer). Specific examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, etc.

[0045] Examples of halogen atoms include fluorine, chlorine, and bromine.

[0046] From the viewpoint of further increasing the amount of carbon dioxide adsorbed in the metal-organic structure, the hydrophobic group is more preferably one or more hydrophobic groups selected from the group consisting of alkyl, halogen and nitro groups, more preferably one or more hydrophobic groups selected from the group consisting of halogen and nitro groups, and particularly preferably nitro groups.

[0047] From the viewpoint of further increasing the amount of carbon dioxide adsorbed in the metal-organic structure, the azole-based organic molecules constituting the metal-organic structure are preferably imidazole-based molecules and / or benzimidazole-based molecules that can have alkyl, halogen or nitro groups, and more preferably imidazole-based molecules and / or benzimidazole-based molecules that have alkyl, halogen or nitro groups.

[0048] The azole-based organic molecules constituting the metal-organic structure are, for example, one or more organic molecules selected from the group consisting of imidazole molecules represented by the following general formula (1), benzimidazole molecules represented by the following general formula (2), triazole molecules represented by the following general formulas (3) and (4), and purine molecules represented by the following general formula (5).

[0049] [Chemical Formula 1]

[0050]

[0051] In equation (1), R 1 ~R 3 Each group is independently a hydrogen atom, alkyl group, halogen atom, nitro group, phenyl group, pyridyl group, or cyano group. From the viewpoint of further increasing the carbon dioxide adsorption capacity in the metal-organic structure, a hydrogen atom or nitro group is preferred. From the same viewpoint, in a more preferred embodiment, R... 1 and R 3 Each can be independently a hydrogen atom or a nitro group, R 2 It is a hydrogen atom.

[0052] As specific examples of imidazole molecules represented by general formula (1), the following compounds can be listed, for example.

[0053] [Table 1]

[0054] Compound (1-1) hydrogen atom hydrogen atom hydrogen atom Compounds (1-2) methyl hydrogen atom hydrogen atom Compounds (1-3) Ethyl hydrogen atom hydrogen atom Compounds (1-4) Nitro hydrogen atom hydrogen atom Compounds (1, 5) hydrogen atom hydrogen atom cyano Compounds (1-6) hydrogen atom chlorine atom chlorine atom Compounds (1-7) hydrogen atom hydrogen atom Nitro

[0055] [Chemical Formula 2]

[0056]

[0057] In equation (2), R 11 ~R 15 Each group is independently a hydrogen atom, alkyl group, halogen atom, nitro group, phenyl group, pyridyl group, or cyano group. From the viewpoint of further increasing the carbon dioxide adsorption capacity in the metal-organic structure, hydrogen atom, alkyl group, halogen atom, or nitro group is preferred. From the same viewpoint, in a more preferred embodiment, R... 11 R 13 R 14 and R 15 For hydrogen atoms, R 12 It can be a hydrogen atom, alkyl group, halogen atom, or nitro group.

[0058] As specific examples of benzimidazole molecules represented by general formula (2), the following compounds can be listed, for example.

[0059] [Table 2]

[0060] Compound (2-1) hydrogen atom hydrogen atom hydrogen atom hydrogen atom hydrogen atom Compound (2-2) hydrogen atom chlorine atom hydrogen atom hydrogen atom hydrogen atom Compounds (2-3) hydrogen atom bromine atom hydrogen atom hydrogen atom hydrogen atom Compounds (2-4) hydrogen atom methyl hydrogen atom hydrogen atom hydrogen atom Compounds (2-5) hydrogen atom A-type storm methyl hydrogen atom hydrogen atom Compounds (2-6) hydrogen atom Nitro hydrogen atom hydrogen atom hydrogen atom

[0061] [Chemical Formula 3]

[0062]

[0063] In equation (3), R 21 ~R 22 Each can be independently a hydrogen atom, alkyl group, halogen atom, nitro group, phenyl group, pyridyl group, or cyano group.

[0064] As specific examples of triazole molecules represented by general formula (3), the following compounds can be listed, for example.

[0065] [Table 3]

[0066] Compound (3-1) hydrogen atom hydrogen atom Compound (3-2) hydrogen atom Nitro Compound (3-3) Nitro hydrogen atom Compounds (3-4) bromine atom bromine atom Compounds (3-5) hydrogen atom chlorine atom

[0067] [Chemical Formula 4]

[0068]

[0069] In equation (4), R 31 ~R 32 Each can be independently a hydrogen atom, alkyl group, halogen atom, nitro group, phenyl group, pyridyl group, or cyano group.

[0070] As specific examples of triazole molecules represented by general formula (4), the following compounds can be listed, for example.

[0071] [Table 4]

[0072] Compound (4-1) hydrogen atom hydrogen atom Compound (4-2) hydrogen atom Nitro Compound (4-3) hydrogen atom methyl Compound (4-4) hydrogen atom bromine atom Compounds (4-5) hydrogen atom chlorine atom Compounds (4-6) bromine atom bromine atom

[0073] [Chemical Formula 5]

[0074]

[0075] In equation (5), R 41 ~R 43 Each can be independently a hydrogen atom, alkyl group, halogen atom, nitro group, phenyl group, pyridyl group, or cyano group.

[0076] As specific examples of purine molecules represented by general formula (5), the following compounds can be listed, for example.

[0077] [Table 5]

[0078] Compound (5-1) hydrogen atom hydrogen atom hydrogen atom Compound (5-2) hydrogen atom Nitro hydrogen atom Compound (5-3) bromine atom hydrogen atom hydrogen atom Compounds (5-4) bromine atom hydrogen atom bromine atom Compound (5-5) hydrogen atom hydrogen atom bromine atom Compounds (5-6) chlorine atom hydrogen atom hydrogen atom

[0079] The metal atoms constituting the metal-organic structure are selected from the group consisting of zinc, cobalt, iron, praseodymium, cadmium, mercury, copper, indium, manganese, lithium, and boron atoms. From the viewpoint of further increasing the carbon dioxide adsorption capacity of the metal-organic structure, the group consisting of zinc, cobalt, and iron atoms is preferred, the group consisting of zinc and cobalt atoms is more preferred, and zinc atoms are even more preferred. The metal atoms constituting the metal-organic structure can be one or more metal atoms selected from the above group.

[0080] The combination of azole organic molecules and metal atoms in a metal-organic structure is acceptable as long as the metal-organic structure has the aforementioned "specific surface area to pore volume ratio", without any particular limitation.

[0081] The combination of azole-based organic molecules and metal atoms in organometallic structures can be, for example, the following combinations:

[0082] Combination (C1) = a combination containing an imidazole molecule represented by general formula (1) and a benzimidazole molecule represented by general formula (2) (preferably only the imidazole molecule and the benzimidazole molecule) as an azole organic molecule, and containing the aforementioned metal atom (preferably a zinc atom, more preferably only a zinc atom) as a metal atom; in this combination (C1), from the viewpoint of further increasing the amount of carbon dioxide adsorbed in the metal-organic structure, the preferred imidazole molecule is 2-nitroimidazole, and the preferred benzimidazole molecule is one or more selected from the group consisting of 5-nitrobenzimidazole, benzimidazole, 5-chlorobenzimidazole, 5-methylbenzimidazole, and 5-bromobenzimidazole; the molar ratio of the imidazole molecule to the benzimidazole molecule is not particularly limited, but from the viewpoint of further increasing the amount of carbon dioxide adsorbed in the metal-organic structure, it is preferably 1 / 9 or more and 9 / 1 or less, more preferably 3 / 7 or more and 7 / 3 or less, and even more preferably 4 / 6 or more and 6 / 4 or less:

[0083] Combination (C2) = Combination of 4-nitroimidazole (preferably only 4-nitroimidazole) as an azole organic molecule and the aforementioned metal atom (preferably zinc atom, more preferably only zinc atom) as a metal atom.

[0084] The ratio of organic molecules to metal atoms in a metal-organic structure is not particularly limited, and is usually determined by the types of organic molecules and metal atoms that make up the metal-organic structure.

[0085] For example, a molecule containing an imidazole molecule (IM) (e.g., an imidazole molecule represented by general formula (1)) and one or more metal atoms (M) selected from the group consisting of zinc, cobalt, iron, copper, manganese, indium, cadmium, lithium, and boron atoms. 1 Metal-organic structures can be composed of the formula: M 1 (IM)2 indicates that boron atoms are not always classified as metals, but are referred to as metal atoms here because organometallic structures have the same properties as metals (the same applies below).

[0086] Additionally, for example, it may contain imidazole molecules (IM) (e.g., imidazole molecules represented by general formula (1)) and benzimidazole molecules (BIM) (e.g., benzimidazole molecules represented by general formula (2), and one or more metal atoms (M) selected from the group consisting of zinc atoms, cobalt atoms, iron atoms, copper atoms, manganese atoms, indium atoms, cadmium atoms, lithium atoms, and boron atoms. 1 Metal-organic structures can be composed of the formula: M 1 (IM)(BIM) are used to represent this.

[0087] Additionally, for example, it contains benzimidazole molecules (BIM) (e.g., benzimidazole molecules represented by general formula (2)) and one or more metal atoms selected from the group consisting of zinc, cobalt, iron, copper, manganese, indium, cadmium, lithium, and boron atoms (M 1 Metal-organic structures can be composed of the formula: M 1 (BIM)2 indicates.

[0088] Additionally, for example, it contains triazole molecules (TRA) (e.g., triazole molecules represented by general formulas (3) and / or (4)) and one or more metal atoms selected from the group consisting of zinc, cobalt, iron, copper, manganese, indium, cadmium, lithium, and boron atoms (M 1 Metal-organic structures can be composed of the formula M 1 (TRA)2 indicates.

[0089] Additionally, for example, it contains purine molecules (PUR) (e.g., triazole molecules represented by general formula (5)) and one or more metal atoms selected from the group consisting of zinc, cobalt, iron, copper, manganese, indium, cadmium, lithium, and boron atoms (M 1 Metal-organic structures can be composed of the formula: M 1 (PUR)2 indicates.

[0090] Additionally, for example, it contains imidazole molecules (IM) (e.g., imidazole molecules represented by general formula (1)) and benzimidazole molecules (BIM) (e.g., benzimidazole molecules represented by general formula (2), and one or more metal atoms (M) selected from the group consisting of zinc atoms, cobalt atoms, iron atoms, copper atoms, manganese atoms, indium atoms, cadmium atoms, lithium atoms, and boron atoms. 1 Metal-organic structures can be composed of the formula: M 1 (IM) x (BIM) y (In the formula, x+y=2) represents.

[0091] Additionally, for example, it contains imidazole molecules (IM) (e.g., imidazole molecules represented by general formula (1)) and two or more metal atoms (M) selected from the group consisting of zinc, cobalt, iron, copper, manganese, indium, cadmium, lithium, and boron atoms. 1 and M 2 Metal-organic structures can be composed of the formula: M 1 M 2 (IM)4 indicates.

[0092] Organometallic compounds can be synthesized by mixing compounds containing specified organic molecules and specified metal atoms in an aqueous or organic solvent. To promote particle growth, they can be manufactured by heating to 60–150°C. Examples of compounds containing specified metal atoms include zinc nitrate, cobalt nitrate, and ferric nitrate. Examples of organic solvents include N,N-diethylformamide, N,N-dimethylformamide, and methanol. The heating time is not particularly limited; for example, it can be 24 hours or more but less than 120 hours, particularly 72 hours or more but less than 120 hours.

[0093] Metal-organic structures are also available as commercially available products.

[0094] For example, ZIF-8 can be obtained as commercially available ZIF-8 (product name: Basolite Z1200, manufactured by BASF, composition formula: Zn(mIm)2).

[0095] In this invention, the metal-organic structure contained in the non-aqueous electrolyte typically has The above and From the viewpoint of further increasing the carbon dioxide adsorption capacity in metal-organic structures, the following pore diameters are preferred. The above and The following pore diameters are particularly preferred. The above and The following pore diameters are further preferred, having The above and The following are the pore diameters.

[0096] The pore diameter depends on the types (especially volume and size) of the organic molecules and metal atoms that make up the metal-organic structure. Therefore, the pore diameter can be adjusted by selecting the types of organic molecules and metal atoms.

[0097] In this specification, pore diameter is defined as "the diameter of the largest sphere that can be contained within a crystal when all atoms in the crystal are formed into rigid spheres with van der Waals radii," and is the pore diameter in a state where no molecules are present within the pore. Therefore, the pore diameter can be calculated from the crystal structure. Such pore diameters are listed in Table 1 of the following literature. The value described in this document can be used:

[0098] ANH PHAN et al., "Synthesis, Structure, and Carbon Dioxide CaptureProperties of Zeolitic Imidazolate Frameworks" (ACCOUNTS OF CHEMICAL RESEARCH58 67January 2010Vol.43,No.1)

[0099] Metal-organic structures typically have an average particle size of 0.01 μm or more and 1 μm or less in non-aqueous electrolytes. From the viewpoint of further increasing the amount of carbon dioxide adsorbed in the metal-organic structure, it is preferable to have an average particle size of 0.02 μm or more and 0.5 μm or less, and more preferably to have an average particle size of 0.05 μm or more and 0.2 μm or less.

[0100] The average particle size of metal-organic structures was calculated using the average of the maximum lengths of any 100 metal-organic structure particles from microscopic photographs.

[0101] The content of the metal-organic structure is not particularly limited, but is generally 0.1% to 50% by weight or more relative to the total amount of the non-aqueous electrolyte. From the viewpoint of further increasing the carbon dioxide adsorption capacity in the metal-organic structure, it is preferably 1% to 10% by weight or more. The non-aqueous electrolyte may contain two or more metal-organic structures with different organic molecular structures and / or different types of metal atoms. In this case, their total content is sufficient to be within the above-mentioned range.

[0102] In addition to metal-organic structures, non-aqueous electrolytes typically contain organic solvents and electrolyte salts.

[0103] As organic solvents, all organic solvents known in the field of non-aqueous electrolytes for electrochemical devices can be listed. Specific examples of organic solvents include cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), butyl carbonate (BC), and vinylene carbonate (VC), which are γ-butyrolactones; chain carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), dipropyl carbonate (DPC), and methyl ethyl carbonate; and tetrahydrofuran, dioxolane, sulfolane, dimethylformamide, dimethylacetamide, and N-methyl-2-pyrrolidone. From the viewpoint of further increasing the carbon dioxide adsorption capacity in the metal-organic structure, organic solvents preferably contain carbonates, and more preferably contain only carbonates. Carbonates refer to carbonates that include the aforementioned cyclic and chain carbonates. When the organic solvent contains carbonates (or only carbonates), the organic solvent contains one or more carbonates selected from the group consisting of cyclic carbonates and chain carbonates. In this case, from the viewpoint of further increasing the amount of carbon dioxide adsorbed in the metal-organic structure, the organic solvent preferably contains one or more (especially two) carbonates selected from the group consisting of cyclic carbonates, and more preferably contains propylene carbonate (PC) and ethylene carbonate (EC).

[0104] The content of organic solvent is generally 40% to 95% by weight or more relative to the total amount of non-aqueous electrolyte, and preferably 70% to 90% by weight or more from the viewpoint of further increasing the amount of carbon dioxide adsorbed in the metal-organic structure.

[0105] As electrolyte salts, all electrolyte salts known in the field of non-aqueous electrolytes for electrochemical devices can be listed. Specific examples of electrolyte salts include LiPF6, LiBF4, LiClO4, LiCF3SO3, LiN(CF3SO2)2, LiN(C2F5SO2)2, LiC(CF3SO2)3, and LiC(C2F5SO2)3. From the viewpoint of further increasing the carbon dioxide adsorption capacity in the metal-organic structure, the electrolyte salt preferably contains LiPF6, and more preferably contains only LiPF6.

[0106] The content of electrolyte salt is usually 5% to 25% by weight or more relative to the total amount of non-aqueous electrolyte, and from the viewpoint of further increasing the amount of carbon dioxide adsorbed in the metal-organic structure, it is preferably 10% to 20% by weight or more.

[0107] Non-aqueous electrolytes may also contain all additives (e.g., binders, fillers, etc.) that have been known in the field of non-aqueous electrolytes for electrochemical devices.

[0108] Examples of adhesives include polyacrylonitrile, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyhexafluoropropylene (PHEP), polyethylene oxide (PEO), polypropylene oxide (PPO), polyphosphazene, polysiloxane, polyvinyl fluoride (PVF), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxyfluoropolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-trifluorochloroethylene copolymer (ECTFE), polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile rubber, polystyrene, polycarbonate, polyethylene oxide, and vinyl chloride. Adhesives can be used alone or in mixtures of two or more monomers. Alternatively, copolymers composed of two or more monomers constituting the aforementioned adhesives can also be used. Specifically, copolymers of PVDF and hexafluoropropylene are examples of such copolymers. From the viewpoint of electrochemical stability, copolymers of PVDF and hexafluoropropylene are preferred.

[0109] As a filler, it can also contain compounds with high heat resistance such as Al2O3, SiO2, TiO2, and BN (boron nitride).

[0110] Non-aqueous electrolytes can be obtained by mixing metal-organic structures, organic solvents, electrolyte salts, and other necessary additives. Non-aqueous electrolytes can be in liquid or gel form.

[0111] [Electrochemical device]

[0112] The electrochemical device of the present invention can be any device that utilizes an electrochemical reaction, including the non-aqueous electrolyte of the present invention described above. Specific examples of such electrochemical devices include, for example, secondary batteries (especially lithium-ion secondary batteries), capacitors (especially electric double-layer capacitors), etc.

[0113] [Rechargeable Battery]

[0114] In the case of a secondary battery, the electrochemical device of the present invention includes, in addition to the aforementioned non-aqueous electrolyte, a positive electrode, a negative electrode, and a separator sealed within an outer packaging. When viewed from above, a sealing portion (encapsulation portion) for retaining the non-aqueous electrolyte within the outer packaging is typically formed at the periphery of the secondary battery. "Top view" refers to the view from directly above the secondary battery in its thickness (height) direction, and is the same as a top view. "Placing" refers to, for example, placing the secondary battery with its largest surface area as the bottom surface. In this specification, the term "secondary battery" refers to a battery capable of repeated charging / discharging. The term "secondary battery" is not overly limited to its name and may also include, for example, "energy storage device."

[0115] For example, Figure 2 As shown, the secondary battery 10 of the present invention includes a non-aqueous electrolyte 1, a positive electrode 2, a negative electrode 3, and a separator 4, with the positive electrode 2 and negative electrode 3 alternately arranged separated by the separator 4. Two external terminals (not shown) are connected to the electrodes (positive or negative) via current collector leads (not shown), resulting in leads being led out from the sealed portion. The non-aqueous electrolyte 1 facilitates the movement of metal ions that have been extracted from the electrodes (positive / negative). Figure 2 In this secondary battery 10, a planar stacked structure is provided, in which a positive electrode 2, a negative electrode 3, and a separator 4 disposed between the positive electrode 2 and the negative electrode 3 are stacked in a planar shape, but it is not limited to a planar stacked structure. For example, the secondary battery may have a winding structure in which the positive electrode 2, the negative electrode 3, and the separator 4 disposed between the positive electrode 2 and the negative electrode 3 are wound into a roller shape. Alternatively, for example, the secondary battery may have a so-called stacked and folded structure, in which the positive electrode 2, the negative electrode 3, and the separator 4 disposed between the positive electrode 2 and the negative electrode 3 are stacked and folded. Figure 2 This is a schematic cross-sectional view of a secondary battery, which is an example of the electrochemical device of the present invention.

[0116] The positive electrode 2 typically comprises at least a positive electrode layer and a positive electrode current collector (foil), with the positive electrode layer disposed on at least one side of the positive electrode current collector. For example, the positive electrode 2 may have a positive electrode layer disposed on both sides of the positive electrode current collector, or it may have a positive electrode layer disposed on one side of the positive electrode current collector. From the viewpoint of further increasing the capacity of secondary batteries, it is preferable that the positive electrode 2 has a positive electrode layer disposed on both sides of the positive electrode current collector. The positive electrode layer contains a positive electrode active material.

[0117] The negative electrode 3 typically comprises at least a negative electrode layer and a negative electrode current collector (foil), with the negative electrode layer disposed on at least one side of the negative electrode current collector. For example, the negative electrode 3 may have a negative electrode layer disposed on both sides of the negative electrode current collector, or it may have a negative electrode layer disposed on one side of the negative electrode current collector. From the viewpoint of further increasing the capacity of secondary batteries, it is preferable that the negative electrode 3 has a negative electrode layer disposed on both sides of the negative electrode current collector. The negative electrode layer contains a negative electrode active material.

[0118] The positive electrode active material in the positive electrode layer and the negative electrode active material in the negative electrode layer are substances that directly participate in electron exchange in the secondary battery, and are the main materials of the positive and negative electrodes that bear the responsibility of charging and discharging, i.e., the battery reaction. More specifically, ions are introduced into the non-aqueous electrolyte from the "positive electrode active material in the positive electrode layer" and the "negative electrode active material in the negative electrode layer". These ions move between the positive and negative electrodes to exchange electrons, thereby carrying out charging and discharging. As such a medium ion, there is no particular limitation as long as it can be charged and discharged, for example, lithium ions or sodium ions (especially lithium ions) can be listed. The positive electrode layer and the negative electrode layer can be layers that can insert and extract lithium ions. That is, it can also be a secondary battery in which lithium ions move between the positive and negative electrodes via a non-aqueous electrolyte to carry out the charging and discharging of the battery. When lithium ions participate in charging and discharging, the secondary battery involved in this embodiment is equivalent to a so-called "lithium-ion secondary battery".

[0119] When the positive electrode active material of the positive electrode layer is composed of granules, for example, to ensure sufficient contact between the particles and maintain their shape, it is preferable to include a binder in the positive electrode layer. Furthermore, to facilitate the smooth transfer of electrons that promote the battery reaction, it is preferable to include a conductive additive in the positive electrode layer. Similarly, when the negative electrode active material of the negative electrode layer is composed of granules, it is preferable to include a binder to ensure sufficient contact between the particles and maintain their shape, and to facilitate the smooth transfer of electrons that promote the battery reaction, a conductive additive may also be included in the negative electrode layer. Thus, since it contains multiple components, the positive electrode layer and the negative electrode layer can also be referred to as a "positive electrode composite material layer" and a "negative electrode composite material layer," respectively.

[0120] The positive electrode active material is preferably a material that facilitates the insertion and extraction of lithium ions. From this viewpoint, the positive electrode active material is preferably, for example, a lithium-containing composite oxide. More specifically, the positive electrode active material is preferably a lithium transition metal composite oxide, which comprises lithium and at least one transition metal selected from the group consisting of cobalt, nickel, manganese, and iron. That is, in the positive electrode layer of the secondary battery according to this embodiment, such a lithium transition metal composite oxide is preferably contained as the positive electrode active material. For example, the positive electrode active material can be lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium titanate, or a substance in which a portion of their transition metal is replaced by another metal. Such a positive electrode active material can be contained alone or in combination of two or more. In a more preferred embodiment, the positive electrode active material contained in the positive electrode layer is lithium cobalt oxide.

[0121] The binder that can be included in the positive electrode layer is not particularly limited, and at least one can be selected from the group consisting of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, and polytetrafluoroethylene. The conductive additive that can be included in the positive electrode layer is not particularly limited, and at least one can be selected from carbon blacks such as thermal cracking carbon black, furnace black, channel black, Ketjen black, and acetylene black, metal powders such as copper, nickel, aluminum, and silver, and polyphenylene derivatives. In a more preferred embodiment, the binder of the positive electrode layer is polyvinylidene fluoride; in another more preferred embodiment, the conductive additive of the positive electrode layer is carbon black. In an even more preferred embodiment, the binder and conductive additive of the positive electrode layer are a combination of polyvinylidene fluoride and carbon black.

[0122] The negative electrode active material is preferably a material that facilitates the insertion and extraction of lithium ions. From this point of view, the negative electrode active material is preferably, for example, various carbon materials, oxides, or lithium alloys.

[0123] Various carbon materials used as negative electrode active materials include graphite (natural graphite, artificial graphite), hard carbon, and diamond-like carbon. In particular, graphite is preferred due to its high electronic conductivity and excellent adhesion to the negative electrode current collector. Oxides used as negative electrode active materials can be at least one selected from the group consisting of silicon oxide, tin oxide, indium oxide, zinc oxide, and lithium oxide. The lithium alloy of the negative electrode active material can be any metal capable of forming an alloy with lithium, such as binary, ternary, or higher alloys of metals like Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, and La with lithium. The preferred structural morphology of such oxides is amorphous. This is because it is less likely to cause deterioration due to inhomogeneities such as grain boundaries or defects. In a more preferred embodiment, the negative electrode active material of the negative electrode layer is artificial graphite.

[0124] The binder that can be included in the negative electrode layer is not particularly limited, and at least one selected from the group consisting of styrene-butadiene rubber, polyvinylidene fluoride, polyimide resins, and polyamide-imide resins can be listed. In a more preferred embodiment, the binder included in the negative electrode layer is styrene-butadiene rubber. The conductive additive that can be included in the negative electrode layer is not particularly limited, and at least one selected from carbon blacks such as thermal cracking carbon black, furnace black, channel black, Ketjen black, and acetylene black, metal powders such as copper, nickel, aluminum, and silver, and polyphenylene derivatives can be listed. It should be noted that the negative electrode layer may also contain components derived from thickeners used in battery manufacturing (such as carboxymethyl cellulose).

[0125] In a more preferred embodiment, the negative electrode active material and the binder in the negative electrode layer are a combination of artificial graphite and styrene-butadiene rubber.

[0126] The positive and negative current collectors used at the positive and negative electrodes are components that help collect or supply electrons generated in the active material due to the battery reaction. Such current collectors can be sheet-like metal components or have a porous or perforated form. For example, the current collector can be a metal foil, perforated metal, mesh, or expanded metal. The positive current collector used at the positive electrode is preferably made of at least one metal foil selected from the group consisting of aluminum, stainless steel, and nickel, for example, aluminum foil. On the other hand, the negative current collector used at the negative electrode is preferably made of at least one metal foil selected from the group consisting of copper, stainless steel, and nickel, for example, copper foil.

[0127] The separator 4 is a component designed to prevent short circuits caused by contact between the positive and negative electrodes and to maintain a non-aqueous electrolyte. In other words, the separator can be described as a component that allows ions to pass through while preventing electron contact between the positive and negative electrodes. Preferably, the separator is a porous or microporous insulating component that has a membrane morphology due to its small thickness. Although this is only an example, a microporous membrane made of polyolefin can also be used as the separator. In this regard, the microporous membrane used as the separator may, for example, contain only polyethylene (PE) or polypropylene (PP) as the polyolefin. Furthermore, the separator may also be a laminate composed of a "microporous membrane made of PE" and a "microporous membrane made of PP".

[0128] The outer packaging body 5 is preferably a flexible bag (soft bag body), but it can also be a hard shell (rigid shell). When the outer packaging body 5 is a flexible bag, the flexible bag is usually formed by a laminated film, and a sealing portion is formed by heat-sealing the periphery. As a laminated film, it is generally a film formed by laminating a metal foil and a polymer film; specifically, a three-layer structure consisting of an outer polymer film / metal foil / inner polymer film can be exemplified. The outer polymer film is used to prevent the permeation of moisture and other substances and damage to the metal foil caused by contact, and polymers such as polyamide and polyester can be used appropriately. The metal foil is used to prevent the permeation of moisture and gas, and foils such as copper, aluminum, and stainless steel can be used appropriately. The inner polymer film is used to protect the metal foil from the influence of electrolytes contained inside and to melt and seal it during heat sealing; polyolefins or acid-modified polyolefins can be used appropriately. The thickness of the laminated film is not particularly limited, but is preferably 1 μm or more and 1 mm or less. For example, in... Figure 2 In the secondary battery 10 shown, the outer packaging 5 is a flexible bag, and the periphery of the lower film 5a and the upper film 5b are heat-sealed when viewed from above.

[0129] When the outer packaging body 6 is a hard shell, the hard shell is usually formed of a metal plate, and a sealing part is formed by irradiating the periphery with a laser. The metal plate is generally made of a metal material such as aluminum, nickel, iron, copper, or stainless steel. The thickness of the metal plate is not particularly limited, but is preferably 1 μm or more and 1 mm or less.

[0130] Secondary batteries can be manufactured using the following methods.

[0131] First, positive electrode 2 and negative electrode 3 are fabricated. Specifically, positive electrode 2 is prepared by mixing positive electrode active material and binder together, adding an organic solvent to form a slurry, and then coating the slurry onto a positive electrode current collector using any coating method, followed by drying. Negative electrode 3 is prepared by mixing negative electrode active material and binder together, adding an organic solvent to form a slurry, and then coating the slurry onto a negative electrode current collector using any coating method, followed by drying. The organic solvents contained in the slurries used to manufacture the positive and negative electrodes of the secondary battery are not particularly limited. For example, alkaline solvents such as dimethyl sulfoxide, dimethylformamide, N-methyl-2-pyrrolidone, propylene carbonate, diethyl carbonate, dimethyl carbonate, and γ-butyrolactone, non-aqueous solvents such as acetonitrile, tetrahydrofuran, nitrobenzene, and acetone, and protic solvents such as methanol and ethanol can be used.

[0132] Next, a positive electrode lead (not shown) is installed on the positive electrode 2, and a negative electrode lead (not shown) is installed on the negative electrode 3. The positive electrode 2 and the negative electrode 3 are stacked in layers with the diaphragm 4 in between to form a stacked electrode body. As needed, the stacked electrode body is wound up. After the wound electrode body is made, protective tape is attached to the outermost periphery of the wound electrode body.

[0133] Using methods such as thermal fusion bonding, the remaining outer peripheral portions of the outer packaging body 5 (5a, 5b) as viewed from above are bonded together to form a bag-shaped outer packaging body. Stacked or wound electrode bodies are then housed inside.

[0134] After injecting non-aqueous electrolyte 1 into the inside of the bag-shaped outer packaging, the outer packaging is sealed using methods such as heat fusion.

[0135] Heat treatments, such as those used for monomer thermal polymerization, can be performed as needed.

[0136] [Electric Double Layer Capacitor]

[0137] In the case where the electrochemical device of the present invention is a double-layer capacitor, in addition to the aforementioned non-aqueous electrolyte, the double-layer capacitor also contains a positive electrode, a negative electrode, and a separator encapsulated within its outer packaging. For example... Figure 3 As shown, the outer packaging body 27 has a positive electrode shell 27a and a negative electrode shell 27b, both of which are formed into a disc-shaped thin plate. A positive electrode 22 containing a positive electrode active material (electrode active material) and a conductive agent is disposed at the center of the bottom of the positive electrode shell 27a. That is, the positive electrode 22 is formed by molding a mixture containing a positive electrode active material (electrode active material) and a conductive agent into a sheet shape on a positive electrode current collector. Furthermore, a separator 24 formed of a porous sheet or membrane such as a microporous membrane, woven fabric, or non-woven fabric is laminated on the positive electrode 22, and then a negative electrode 23 is laminated on the separator 24. That is, the negative electrode 23, like the positive electrode 22, is formed by molding a mixture containing a negative electrode active material (electrode active material) and a conductive agent into a sheet shape on a metal negative electrode current collector 25. Furthermore, the negative electrode 23 is disposed opposite to the positive electrode 22 through the diaphragm 24, and a metal spring 26 is mounted on the negative electrode current collector 25. In addition, the non-aqueous electrolyte 21 fills the internal space, and the negative electrode housing 27b is fixed to the positive electrode housing 27a against the force of the metal spring 26 and is sealed by a gasket 28. Figure 3 This is a schematic cross-sectional view of a coin-type electric double-layer capacitor, which is one embodiment of the electric double-layer capacitor involved in this invention.

[0138] In the double-layer capacitor 20, before a voltage is applied between the positive electrode 22 and the negative electrode 23, charged particles in the non-aqueous electrolyte 21 are irregularly distributed within the non-aqueous electrolyte 21. On the other hand, when a voltage is applied between the positive electrode 22 and the negative electrode 23, positive ions in the positive electrode 22 and negative ions in the non-aqueous electrolyte 21 are distributed in pairs at the interface between the positive electrode (positive electrode active material) 22 and the non-aqueous electrolyte 21. Similarly, negative ions in the negative electrode 23 and positive ions in the non-aqueous electrolyte 21 are distributed in pairs at the interface between the negative electrode (negative electrode active material) 23 and the non-aqueous electrolyte 21. As a result, at the interface between the positive electrode 22 and the non-aqueous electrolyte 21, positive and negative ions are distributed in a layered manner, and at the interface between the negative electrode 23 and the non-aqueous electrolyte 21, negative and positive ions are also distributed in a layered manner, thereby forming a double layer with a large surface area.

[0139] As a positive electrode active material, it can be any material that can be used as a positive electrode active material in the field of electric double-layer capacitors. Specific examples of positive electrode active materials include activated carbon.

[0140] As a negative electrode active material, any material that can be used as a negative electrode active material in the field of electric double-layer capacitors can be employed. Specific examples of negative electrode active materials include, for instance, carbon.

[0141] There are no particular limitations on the conductive agents that can be included in the positive and negative electrodes. For example, conductive polymers such as graphite, carbon black, acetylene black, etc., carbon fibers such as vapor-grown carbon fibers, carbon nanotubes, carbon nanotubes, etc., and conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polybenzoxene can be used. The conductive agent can be used alone or in combination of two or more.

[0142] The positive and negative electrodes can each contain an adhesive independently. As an adhesive, any adhesive suitable for use in the positive and negative electrodes of an electric double-layer capacitor can be employed. Specific examples of such adhesives include polyethylene, polypropylene, polyvinylidene fluoride, polyhexafluoropropylene, polytetrafluoroethylene, ethylene oxide, carboxymethyl cellulose, styrene-butadiene copolymer, and polymethyl methacrylate. The adhesive can be used alone or in combination of two or more.

[0143] The separator 24 can be selected from the same range as the separator 4 of the secondary battery.

[0144] Double-layer capacitors can be manufactured using the following methods.

[0145] First, the positive electrode 22 and the negative electrode 23 are fabricated. Specifically, the positive electrode 22 is obtained by mixing a positive electrode active material, a conductive agent, and a binder together, adding an organic solvent to prepare a slurry, and then coating the slurry onto a positive electrode current collector using any coating method, followed by drying. The negative electrode 23 is obtained by mixing a negative electrode active material, a conductive agent, and a binder together, adding an organic solvent to prepare a slurry, and then coating the slurry onto a negative electrode current collector using any coating method, followed by drying. The organic solvent contained in the slurry used to manufacture the positive and negative electrodes of the double-layer capacitor is not particularly limited; for example, the same organic solvent contained in the slurry used to manufacture the positive and negative electrodes of a secondary battery can be used.

[0146] Next, the positive electrode 22 is immersed in a non-aqueous electrolyte 21. Then, the negative electrode 23 and the negative current collector 25 are arranged opposite the positive electrode 22 with the diaphragm 24, which is immersed in the non-aqueous electrolyte 21, in between. Then, the non-aqueous electrolyte 21 is injected into the internal space. Next, the metal spring 26 is placed on the negative current collector 25, and the washer 28 is placed around the perimeter. The negative electrode housing 27b is fixed to the positive electrode housing 27a using a riveting machine or the like for outer packaging and encapsulation, thereby producing a coin-shaped double-layer capacitor.

[0147] The double-layer capacitor described in this embodiment is a coin-shaped double-layer capacitor, but the shape is not particularly limited. The double-layer capacitor can be cylindrical, square, plate, etc. In addition, the outer packaging 27 is not particularly limited, and can be a metal shell, molding resin, aluminum laminate, etc.

[0148] Example

[0149] [Fabrication of Metal-Organic Structures]

[0150] (Example 1)

[0151] The metal-organic structure ZIF-78 was synthesized using the following method.

[0152] A 60 mL solution of N,N-dimethylformamide containing 0.2 M each of 2-nitroimidazole and 5-nitrobenzimidazole as organic molecules, and a 20 mL solution of N,N-dimethylformamide containing 0.2 M zinc nitrate were mixed and heated at 140 °C for 96 hours in a stainless steel sleeve to precipitate the mixture, thus obtaining a powder. The powder was further washed three times with N,N-dimethylformamide solution, centrifuged, and dried to obtain ZIF-78.

[0153] ZIF-78 is composed of zinc atoms and 2-nitroimidazole and 5-nitrobenzoazole, represented by the formula Zn(2nIm)(5nbIm), with a specific surface area / pore volume ratio of 0.67. The pore diameter is... The average particle size is 0.1 μm.

[0154] (Example 2)

[0155] ZIF-68 was synthesized using the same method as ZIF-78, except that a solution of N,N-dimethylformamide containing 0.2 M each of 2-nitroimidazole and benzimidazole was used.

[0156] ZIF-68 is composed of zinc atoms and 2-nitroimidazole and benzimidazole, represented by the formula Zn(2nIm)bIm, with a specific surface area / pore volume ratio of 0.57. The pore diameter is... The average particle size is 0.1 μm.

[0157] (Example 3)

[0158] ZIF-69 was synthesized using the same method as ZIF-78, except that a solution of N,N-dimethylformamide containing 0.2 M each of 2-nitroimidazole and 5-chlorobenzimidazole was used.

[0159] ZIF-69 is composed of zinc atoms and 2-nitroimidazole and 5-chlorobenzimidazole, represented by the formula Zn(2nIm)(5cbIm), with a specific surface area / pore volume ratio of 0.62. The pore diameter is... The average particle size is 0.1 μm.

[0160] (Example 4)

[0161] ZIF-79 was synthesized using the same method as ZIF-78, except that a solution of N,N-dimethylformamide containing 0.2 M each of 2-nitroimidazole and 5-methylbenzimidazole was used.

[0162] ZIF-79 is composed of zinc atoms and 2-nitroimidazole and 5-methylbenzimidazole, represented by the formula Zn(2nIm)(5mbIm), with a specific surface area / pore volume ratio of 0.63. The pore diameter is... The average particle size is 0.1 μm.

[0163] (Example 5)

[0164] ZIF-81 was synthesized using the same method as ZIF-78, except that a solution of N,N-dimethylformamide containing 0.2 M each of 2-nitroimidazole and 5-bromobenzimidazole was used.

[0165] ZIF-81 is composed of zinc atoms and 2-nitroimidazole and 5-bromobenzimidazole, represented by the formula Zn(2nIm)(5bbIm), with a specific surface area / pore volume ratio of 0.62. The pore diameter is... The average particle size is 0.1 μm.

[0166] (Example 6)

[0167] Zn(4nIm)2 was synthesized using the same method as ZIF-78, except that an N,N-dimethylformamide solution containing 0.4 M 4-nitroimidazole was used.

[0168] Zn(4nIm)₂ is composed of zinc atoms and 4-nitroimidazole, represented by the formula Zn(4nIm)₂, with a specific surface area / pore volume ratio of 0.70. The pore diameter is... The average particle size is 0.1 μm.

[0169] (Comparative Example 1)

[0170] ZIF-8 was synthesized using the same method as ZIF-78, except that a solution of N,N-dimethylformamide containing 0.4 M 2-methylimidazole was used.

[0171] ZIF-8 is composed of zinc atoms and 2-methylimidazole, represented by the formula Zn(2mIm)2, and has a specific surface area / pore volume ratio of 0.50. The pore diameter is... The average particle size is 0.1 μm.

[0172] (Comparative Example 2)

[0173] ZIF-77 was synthesized using the same method as ZIF-78, except that a solution of N,N-dimethylformamide containing 0.4 M of 2-nitroimidazole was used.

[0174] ZIF-77 is composed of zinc atoms and 2-nitroimidazole, represented by the formula Zn(2nIm)2, with a specific surface area / pore volume ratio of 0.74. The pore diameter is... The average particle size is 0.1 μm.

[0175] (Comparative Example 3)

[0176] ZIF-4 was synthesized using the same method as ZIF-78, except that a solution of N,N-dimethylformamide containing 0.4 M imidazole was used.

[0177] ZIF-4 is composed of zinc atoms and imidazole, represented by the formula Zn(Im)2, and has a specific surface area / pore volume ratio of 1.02. The pore diameter is... The average particle size is 0.1 μm.

[0178] (Comparative Example 4)

[0179] ZIF-7 was synthesized using the same method as ZIF-78, except that an N,N-dimethylformamide solution containing 0.4 M benzimidazole was used.

[0180] ZIF-7 is composed of zinc atoms and benzimidazole, represented by the formula Zn(bIm)2, and has a specific surface area / pore volume ratio of 1.02. The pore diameter is... The average particle size is 0.1 μm.

[0181] (Structure of metal-organic structures and specific surface area / pore volume ratio)

[0182] Using a single crystal determination apparatus (VariMax, MoKα ray) manufactured by Rigaku Corporation (for analyzing the structure of extremely small crystals), Irradiation time was 4 seconds, d = 45 mm, 2θ = -20°C, temperature = -180°C. Crystallographic diffraction images were obtained, and the diffraction images were analyzed using the software "Yadokari XG2009" to obtain the structure of unit crystals.

[0183] Calculate the diameter of the probe molecule based on the obtained unit crystal structure. The specific surface area (SSA) and pore volume were used to calculate the ratio of SSA to pore volume. For example, in the case of ZIF-78 in Example 1, the SSA was 2004 m². 2 / g, pore volume is 0.30cm³ 3 / g, yielding a specific surface area / pore volume ratio of 0.67. Examples 2-6 were also calculated using the same method, as shown in Table 6.

[0184] While specific surface area and pore volume can be experimentally measured using methods such as the BET method, the results are inaccurate due to variations in cleaning or measurement conditions. Therefore, the method calculated from the crystal structure described above allows for a more accurate evaluation of CO2 adsorption selectivity.

[0185] The following abbreviations were used in the composition:

[0186] 2nIm: 2-Nitroimidazole;

[0187] bIm: Benzimidazole;

[0188] 4nIm: 4-Nitroimidazole;

[0189] 5mbIm: 5-Methylbenzimidazole;

[0190] 5cbIm: 5-Chlorobenzimidazole;

[0191] 5bbIm: 5-bromobenzimidazole;

[0192] 5nbIm: 5-Nitrobenzimidazole.

[0193] (Prediction of CO2 adsorption capacity)

[0194] The CO2 adsorption capacity of non-aqueous electrolytes containing metal-organic structures can be predicted using the grand canonical Monte Carlo (GCMC) method. For metal-organic structures, the adsorption capacities (equilibrium state) of CO2 at 100 kPa, ethylene carbonate at 10000 kPa, and propylene carbonate at 10000 kPa were calculated at 298 K. The software used was Materials Studio Sorption (Dassault Systèmes), and calculations were performed using the force field of the attached COMPASS II software via the Metropolitan method. Specifically, calculations were performed using the structures / conditions shown in Table 7 below, under the simulation conditions shown in Tables 8-1 to 8-25 below.

[0195] The predicted values ​​and the measured values ​​described below were evaluated according to the following benchmarks.

[0196] ◎◎:120mL / g≤Gas adsorption capacity (optimal);

[0197] ◎: 100mL / g ≤ gas adsorption capacity < 120mL / g (excellent);

[0198] ○: 60mL / g ≤ gas adsorption capacity < 100mL / g (good);

[0199] △: 50mL / g ≤ gas adsorption capacity < 60mL / g (no practical problems);

[0200] ×: Gas adsorption capacity < 50 mL / g (This has practical problems).

[0201] The results are shown in Table 6.

[0202] (Determination of CO2 adsorption capacity)

[0203] according to Figure 4 The method shown was used to determine the amount of CO2 adsorbed into a non-aqueous electrolyte containing a metal-organic structure. Details are as follows.

[0204] (1) An outer packaging body 51 for measurement was prepared. The outer packaging body 51 was obtained by heat-sealing the three outer peripheral portions and the central portion 60 of two rectangular laminated films when viewed from above. A gas adsorption chamber 51a and a gas injection chamber 51b were provided by forming a sealing portion of the central portion 60. When forming the sealing portion of the central portion 60, a non-sealing portion 61 was provided for moving CO2 gas as described later. An injection port 52 for injecting gas was provided in the gas injection chamber 51b.

[0205] (2) The outer packaging 51 is folded back at the heat-sealed portion of the central section 60, and 2 mL of non-aqueous electrolyte is injected through the opening of the gas adsorption chamber 51a. This non-aqueous electrolyte contains 5 wt% of the metal-organic structure shown in each example / comparative example, 1 mol / kg of LiPF6, and is composed of ethylene carbonate and propylene carbonate in a 1:1 ratio. Furthermore, it is placed at 60°C for one week to allow the solvent to permeate the metal-organic structure. It should be noted that clamps 53 are used to restrict the movement of the contents of the gas adsorption chamber 51a and the gas injection chamber 51b at their lower parts. The total content of ethylene carbonate and propylene carbonate is 85% by weight relative to the total amount of the non-aqueous electrolyte. The content of LiPF6 is 15% by weight relative to the total amount of the non-aqueous electrolyte.

[0206] (3) Heat seal the opening of the gas adsorption chamber 51a and weigh it. Calculate the weight Ws of the test body only based on the weight of the clamp 53, gas injection port 52, and test body (i.e., electrolyte solution sealed in the outer packaging), the weight of the clamp 53 and the gas injection port 52.

[0207] (4) CO2 gas (1.5 mL) was injected into the gas injection chamber 51b through the gas injection port 52.

[0208] (5) Gas leakage is prevented by heat-sealing the gas injection port 52 near the gas injection port 52 in the gas injection chamber 51b.

[0209] (6) Based on Archimedes' principle, the volume (V1) of the test body equipped with clamp 53 was measured.

[0210] (7) Remove clamp 53 to move CO2 gas from gas injection chamber 51b to gas adsorption chamber 51a and fully adsorb CO2 gas.

[0211] (8) After adsorbing CO2 gas, the volume (V2) of the test body equipped with clamp 53 was measured according to Archimedes' principle.

[0212] The gas adsorption amount was calculated from the values ​​measured using the above methods according to the following formula. This value was evaluated using the same criteria as the predicted values. The results are shown in Table 6.

[0213] Gas adsorption capacity (mL / g) = (V1-V2) / Ws

[0214]

[0215] The predicted values ​​and measured values ​​obtained by the GCMC method correspond / match extremely well. That is, the same results are obtained for both the predicted and measured values. Therefore, it can be confirmed that the metal-organic structures of Examples 1-6, compared to the metal-organic structures of Comparative Examples 1-4, can more fully obtain CO2 adsorption performance in the electrolyte. Specifically, by making the ratio of specific surface area to pore volume... The above and The following (preferred) The above and The following is preferred. The above and The following methods can enable a more complete and greater adsorption of CO2 in the electrolyte.

[0216] When a secondary battery is manufactured using the non-aqueous electrolyte containing a metal-organic structure obtained in the various embodiments, the secondary battery has the original function of a secondary battery.

[0217] When a double-layer capacitor is manufactured using a non-aqueous electrolyte containing a metal-organic structure obtained in the various embodiments, the double-layer capacitor has the original function of a double-layer capacitor.

[0218]

[0219] In Table 7, the RCSR topology is based on the following literature (1).

[0220] (1) O'Keeffe, M.; Peskov, MA; Ramsen, SJ; Yaghi, OM

[0221] [Table 8-1]

[0222]

[0223] [Table 8-2]

[0224]

[0225] [Table 8-3]

[0226]

[0227] [Table 8-4]

[0228]

[0229] [Table 8-5]

[0230]

[0231] [Table 8-6]

[0232]

[0233] [Table 8-7]

[0234]

[0235] [Table 8-8]

[0236]

[0237] [Table 8-9]

[0238]

[0239] [Table 8-10]

[0240]

[0241] [Table 8-11]

[0242]

[0243] [Table 8-12]

[0244]

[0245] [Table 8-13]

[0246]

[0247] [Table 8-14]

[0248]

[0249] [Table 8-15]

[0250]

[0251] [Table 8-16]

[0252]

[0253] [Table 8-17]

[0254]

[0255] [Table 8-18]

[0256]

[0257] [Table 8-19]

[0258]

[0259] [Table 8-20]

[0260]

[0261] [Table 8-21]

[0262]

[0263] [Table 8-22]

[0264]

[0265] [Table 8-23]

[0266]

[0267] [Table 8-24]

[0268]

[0269] [Table 8-25]

[0270]

[0271] Industrial availability

[0272] Electrochemical devices incorporating the metal-organic structures described in this invention can be used in various fields where batteries or energy storage are envisioned. While merely examples, the electrochemical devices described in this invention, particularly secondary batteries and double-layer capacitors, can be used in the field of electronic assembly. The secondary battery and double-layer capacitor according to one embodiment of the present invention can also be used in the following fields: electrical / information / communication fields using mobile devices, etc. (e.g., electrical / electronic equipment fields or mobile equipment fields including small electronic devices such as mobile phones, smartphones, laptops, digital cameras, activity meters, ARM computers, electronic paper, wearable devices, RFID tags, card-type electronic money, smartwatches, etc.); home / small industrial applications (e.g., power tools, golf carts, home / care / industrial robots); large industrial applications (e.g., forklifts, elevators, port cranes); transportation system fields (e.g., hybrid vehicles, electric vehicles, buses, trams, electric-assisted bicycles, electric motorcycles, etc.); power system applications (e.g., various power generation, load regulators, smart grids, general household-installed energy storage systems, etc.); medical applications (medical devices such as headphones and hearing aids); pharmaceutical applications (medical management systems, etc.); IoT fields; and space / deep-sea applications (e.g., space probes, underwater research vessels, etc.).

[0273] Explanation of reference numerals in the attached figures

[0274] 1: Non-aqueous electrolyte; 2: Positive electrode; 3: Negative electrode; 4: Separator; 5: Outer packaging; 10: Secondary battery; 20: Electric double layer capacitor; 21: Non-aqueous electrolyte; 22: Positive electrode; 23: Negative electrode; 24: Separator; 27: Outer packaging.

Claims

1. A non-aqueous electrolyte, It is a mixture of a metal-organic structure, an organic solvent, and an electrolyte salt, wherein the metal-organic structure contains an azole-based organic molecule capable of having hydrophobic groups and metal atoms, and the ratio of specific surface area to pore volume is 0.65 Å. -1 Above and 0.71Å -1 the following, The azole-based organic molecules are selected from one or more organic molecules in the group consisting of imidazole, benzimidazole, triazole, and purine. The hydrophobic group is one or more substituents selected from the group consisting of alkyl, halogen, nitro, phenyl, and pyridyl groups. The metal-organic structure contains one or more atoms selected from the group consisting of metal atoms and boron atoms, wherein the metal atoms are selected from one or more of zinc atoms, cobalt atoms, iron atoms, praseodymium atoms, cadmium atoms, mercury atoms, copper atoms, indium atoms, manganese atoms and lithium atoms.

2. The non-aqueous electrolyte according to claim 1, wherein, The specific surface area is 1700 m². 2 / g or more and 2500m 2 / g or less.

3. The non-aqueous electrolyte according to claim 1, wherein, The specific surface area is 1950m² 2 / g or more and 2300m 2 / g or less.

4. A non-aqueous electrolyte, It is a mixture of a metal-organic structure, an organic solvent, and an electrolyte salt, wherein the metal-organic structure contains an azole-based organic molecule capable of having hydrophobic groups and metal atoms, and the ratio of specific surface area to pore volume is 0.55 Å. -1 Above and 0.71Å -1 Hereinafter, the specific surface area is 1950 m². 2 / g or more and 2300m 2 / g or less The azole-based organic molecules are selected from one or more organic molecules in the group consisting of imidazole, benzimidazole, triazole, and purine. The hydrophobic group is one or more substituents selected from the group consisting of alkyl, halogen, nitro, phenyl, and pyridyl groups. The metal-organic structure contains one or more atoms selected from the group consisting of metal atoms and boron atoms, wherein the metal atoms are selected from one or more of zinc atoms, cobalt atoms, iron atoms, praseodymium atoms, cadmium atoms, mercury atoms, copper atoms, indium atoms, manganese atoms and lithium atoms.

5. The non-aqueous electrolyte according to any one of claims 1 to 4, wherein, The pore volume is 0.20 cm³. 3 / g or more and 0.50cm 3 / g or less.

6. The non-aqueous electrolyte according to any one of claims 1 to 4, wherein, The pore volume is 0.28 cm³. 3 / g or more and 0.35cm 3 / g or less.

7. The non-aqueous electrolyte according to any one of claims 1 to 4, wherein, The azole organic molecule is one or more organic molecules selected from the group consisting of imidazole molecules represented by the following general formula (1), benzimidazole molecules represented by the following general formula (2), triazole molecules represented by the following general formulas (3) and (4), and purine molecules represented by the following general formula (5): In equations (1) to (5), R 1 ~R 3 R 11 ~R 15 R 21 ~R 22 R 31 ~R 32 and R 41 ~R 43 Each can be independently a hydrogen atom, alkyl group, halogen atom, nitro group, phenyl group, or pyridyl group.

8. The non-aqueous electrolyte according to claim 7, wherein, The metal-organic structure contains the imidazole molecule and the benzimidazole molecule as the azole organic molecule, or contains 4-nitroimidazole as the azole organic molecule, and contains zinc atoms as the metal atom.

9. The non-aqueous electrolyte according to any one of claims 1 to 4, wherein, The non-aqueous electrolyte contains the metal-organic structure in an amount of 0.1% to 50% by weight relative to the total amount of the non-aqueous electrolyte.

10. The non-aqueous electrolyte according to any one of claims 1 to 4, wherein, The non-aqueous electrolyte also contains organic solvents and electrolyte salts.

11. The non-aqueous electrolyte according to claim 10, wherein, The organic solvent contains carbonates.

12. The non-aqueous electrolyte according to any one of claims 1 to 4, wherein, The non-aqueous electrolyte is contained in the electrochemical device.

13. The non-aqueous electrolyte according to claim 12, wherein, The electrochemical device is a lithium-ion secondary battery or an electric double-layer capacitor.

14. An electrochemical device, The non-aqueous electrolyte comprising any one of claims 1 to 13.

15. The electrochemical device according to claim 14, wherein, The electrochemical device is a lithium-ion secondary battery or an electric double-layer capacitor.

16. The electrochemical device according to claim 14 or 15, wherein, The electrochemical device is a lithium-ion secondary battery. The lithium-ion secondary battery also includes a positive electrode and a negative electrode. The positive electrode and the negative electrode have layers capable of inserting and de-inserting lithium ions.

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