Polymer, film, solution, electrode composite, and battery

Abstract

To provide a polymer film for a lithium-air battery exhibiting superior battery life and capacity.SOLUTION: There is provided a polymer wherein atomic number density of atoms having charge density of -1.0 or more and -0.5 or less is 0% or more and 7% or less, and atomic number density of atoms having charge density of 0.25 or more and 1.0 or less is 5% or more and 100% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to polymers, films, solutions, electrode composites, and batteries.

Background Art

[0002] In recent years, for the purpose of reducing the weight and increasing the energy density of batteries, metal Li anode batteries, batteries, air batteries, etc. have been actively studied, and the design of the positive electrode, negative electrode, separator, electrolyte, etc. has been advanced toward practical application. Among them, lithium-air batteries are expected to be the ultimate secondary batteries because they have the highest theoretical capacity (Patent Document 1). In addition, polymer films have been actively studied as separators and electrolytes from the perspective of processability. (Patent Documents 2 to 4)

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the separator used in Patent Document 1 is an inorganic solid electrolyte, and there are problems in processability. In addition, for the polymer films of Patent Documents 2 to 4 to achieve practical levels of battery life and capacity in lithium-air batteries, further improvement in the conductivity of ions contributing to battery operation, such as lithium ions, and the performance of preventing the permeation of substances other than those ions is required. Therefore, in view of the above circumstances, an object of the present invention is to provide a polymer film for a lithium-air battery having excellent battery life and capacity.

Means for Solving the Problem

[0005] To solve the above problems, the present invention has the following features. [I] A polymer in which the atomic number density of atoms having a charge density of -1.0 or more and -0.5 or less is 0% or more and 7% or less, and the atomic number density of atoms having a charge density of 0.25 or more and 1.0 or less is 5% or more and 100% or less. [II] The polymer according to [I], wherein the glass transition temperature of the polymer is 51°C or more and 400°C or less. [III] The polymer according to [I] or [II], wherein the atomic number density of atoms having a charge density of -0.5 or more and less than 0 is 9% or more and 100% or less. [IV] The polymer according to any one of [I] to [III], wherein the atomic number density of hydrogen atoms (H atoms) having a charge density of 0.25 or more and 1 or less is 5% or more and 100% or less. [V] A film containing the polymer according to any one of [I] to [IV]. [VI] The film according to [V], which has a non-porous region. [VII] The film according to [V] or [VI], wherein the cation concentration is 1 μmol / g or more and 50000 μmol / g or less. [VIII] The film according to any one of [V] to [VII], wherein the lithium ion concentration is 1 μmol / g or more and 50000 μmol / g or less. [IX] The ionic conductivity is 1.0×10 -7 The film according to any one of [V] to [VIII], which is S / cm or more and 1.0×10 S / cm or less. [X] The film according to any one of [V] to [IX], wherein the cation transference number is 0.5 or more and 1.0 or less. [XI] The film according to any one of [V] to [X], wherein the haze is 0% or more and 30% or less. [XII] The film contains at least one of bis(trifluoromethanesulfonamide) ion, bis(fluorosulfonamide) ion, trifluoromethanesulfonic acid ion, PF 6 ion, ClO 4 ion, BF 4 ion, and is the film according to any one of [V] to [XI]. [XIII] The film according to any one of [V] to [XII], wherein the lithium salt weight concentration is 0 wt% or more and 80 mass% or less. [XIV] The association constant with the polymer is 1.0 M -1 or more and 1.0×10 10 M -1 or less, and the film according to any one of [V] to [XIII] contains an anion. [XV] A solution containing the polymer according to any one of [I] to [IV].[[]END]] [XVI] An electrode complex having the film according to any one of [V] to [XIII] and an electrode in proximity. [XVII] A battery containing the polymer according to any one of [I] to [IV] or the film according to any one of [V] to [XIII].[[]END]] [XVIII] The battery according to [XVII], wherein the weight ratio of the electrolytic solution to the film is 0 or more and 5 or less. [XIX] [XVII] or [XVIII], and a vehicle, unmanned transporter, electronic device, unmanned aerial vehicle, or stationary power source containing the battery. [Advantages of the Invention]

[0006] According to the present invention, it is possible to provide a polymer, a film excellent in ionic conductivity, cation transference number, and liquid separation property, and a battery excellent in discharge capacity and cycle life. [Embodiments for Carrying Out the Invention]

[0007] The present invention will be described in detail below.

[0008] As one aspect of the present invention, there is provided a polymer that can be used for a film excellent in ionic conductivity, cation transport rate, and liquid separation property. Further, as one aspect of the present invention, there is provided a film using such a polymer. Further, as one aspect of the present invention, there is provided a solution containing such a polymer.

[0009] In the polymer of the present invention, the atomic number density of atoms having a charge density of -1.0 or more and -0.5 or less is 0% or more and 7% or less. 0% or more and 5% or less is preferable, 0% or more and 3% or less is more preferable, 0% or more and 2% or less is further preferable, and 0% or more and 1% or less is particularly preferable. Atoms having a charge density of -1.0 or more and -0.5 or less show a strong interaction with cations. When the atomic number density of atoms having a charge density of -1.0 or more and -0.5 or less is within the above range, the interaction with cations becomes appropriate, and a film containing such a polymer exhibits good ionic conductivity and cation transport rate. Specific examples of atoms having a charge density of -1.0 or more and -0.5 or less include the O atom and N atom of an amide group, the O atom and N atom of an imide group, and the O atom of a sulfone group. The charge density can be calculated by quantum mechanical calculations described later. The atomic number density in the present invention is the number ratio of specific atoms to the total number of atoms contained in the repeating structure. In the case of a copolymer having two or more repeating structures, it corresponds to the total number of atoms contained in the repeating structure. For example, assume a polymer having two repeating structures in which all atoms in the repeating structure are composed of 4 and 2 respectively, and each contains 1 oxygen atom. When the copolymerization ratio of the repeating structure with 4 atoms is 0.7 and the copolymerization ratio of the repeating structure with 2 atoms is 0.3, the atomic number density of the oxygen atoms in such a polymer is (1×0.7 + 1×0.3) / (4×0.7 + 2×0.3)×100 = 29%. Polymers having the atomic number density of atoms having a charge density of -1.0 or more and -0.5 or less within the above range are not particularly limited, but examples include the polymers described later.

[0010] The polymer of the present invention has an atomic number density of atoms with a charge density of 0.25 or more and 1.0 or less of 5% or more and 100% or less. 10% or more and 100% or less is preferable, 18% or more and 100% or less is more preferable, 21% or more and 50% or less is further preferable, and 23% or more and 50% or less is particularly preferable. Atoms with a charge density of 0.25 or more and 1.0 or less show strong interaction with anions. When the atomic number density of atoms with a charge density of 0.25 or more and 1.0 or less is within the above range, in addition to an increase in the number of dissociated ions in the film, anions can be captured, and a film showing good ionic conductivity and cation transference number can be obtained. Specific examples of atoms with a charge density of 0.25 or more and 1.0 or less include C atoms and H atoms of thioamide groups and thiourea groups, C atoms of cyano groups, C atoms and H atoms of amide groups and urea groups, C-F groups, and C atoms of C-Cl. The polymer having the atomic number density of atoms with a charge density of 0.25 or more and 1.0 or less within the above range is not particularly limited, but examples include the polymers described later.

[0011] The polymer of the present invention preferably has an atomic number density of atoms with a charge density of -0.5 or more and less than 0 of 9% or more and 100% or less, more preferably 15% or more and 100% or less, further preferably 40% or more and 70% or less, and particularly preferably 42% or more and 70% or less. Atoms with a charge density of -0.5 or more and less than 0 show a smaller interaction with anions than atoms with a charge density of -1.0 or more and -0.5 or less. When the atomic number density of atoms with a charge density of -0.5 or more and less than 0 is within the above range, while suppressing excessive interaction with cations, the number of dissociated ions in the film can be increased, and a film showing good ionic conductivity and cation transference number can be obtained. Specific examples of atoms with a charge density of -0.5 or more and less than 0 include S atoms and N atoms of thioamide groups and thiourea groups, N atoms of cyano groups, F atoms of C-F groups, Cl atoms of C-Cl, and O atoms of aliphatic ethers. The polymer having the atomic number density of atoms with a charge density of -0.5 or more and less than 0 within the above range is not particularly limited, but examples include the polymers described later.

[0012] The polymer of the present invention preferably has an atomic number density of atoms with a charge density of -0.5 or more and less than -0.3 of 9% or more and 100% or less, more preferably 15% or more and 100% or less, still more preferably 40% or more and 70% or less, and particularly preferably 42% or more and 70% or less. Atoms with a charge density of -0.5 or more and less than -0.3 exhibit a smaller interaction with anions than atoms with a charge density of -1.0 or more and -0.5 or less, and at the same time, promote the dissociation of Li salts more than atoms with a charge density of -0.3 or more and 0 or less. When the atomic number density of atoms with a charge density of -0.5 or more and less than -0.3 is within the above range, the number of dissociated ions in the film can be increased while suppressing excessive interaction with cations, showing good ionic conductivity and cation transference number. Specific examples of atoms with a charge density of -0.5 or more and less than -0.3 include the S atom and N atom of a thioamide group and a thiourea group, the N atom of a cyano group, the F atom of a C-F group, and the Cl atom of a C-Cl. The polymer having the atomic number density of atoms with a charge density of -0.5 or more and less than -0.3 within the above range is not particularly limited, and examples thereof include the polymers described later.( The polymer of the present invention preferably has an atomic number density of hydrogen atoms (H atoms) with a charge density of 0.25 or more and 1 or less of 5% or more and 100% or less, more preferably 7% or more and 50% or less, still more preferably 9% or more and 50% or less, and particularly preferably 10% or more and 50% or less. H atoms with a charge density of 0.25 or more and 1.0 or less exhibit a strong interaction with anions compared to other atoms. When the atomic number density of H atoms with a charge density of 0.25 or more and 1 or less is within the above range, in addition to increasing the number of dissociated ions in the film, anions can be captured, and a film showing good ionic conductivity and cation transference number can be obtained. Specific examples of atoms with a charge density of 0.25 or more and 1.0 or less include the H atom of a thioamide group and a thiourea group, an amide group, and the H atom of a urea group. The polymer having the atomic number density of H atoms with a charge density of 0.25 or more and 1 or less within the above range is not particularly limited, and examples thereof include the polymers described later.

[0013] The polymer of the present invention preferably has a glass transition temperature of 51°C or higher and 400°C or lower, more preferably 100°C or higher and 400°C or lower, still more preferably 150°C or higher and 400°C or lower, and particularly preferably 180°C or higher and 400°C or lower. By being within the above range, in the film containing the polymer of the present invention, the diffusion of the solvent in the electrolytic solution is suppressed, the decomposition of the electrolytic solution on the electrode surface and the crossover of the decomposition products between the positive and negative electrodes are reduced, and the effect of improving the battery life can be obtained. The glass transition temperature can be measured by the method using DMA (N,N-dimethylacetamide) described later. The method for setting the glass transition temperature of the polymer within the above range is not particularly limited, and for example, using the polymer described later can be mentioned.

[0014] For confirming each constituent component and its content of the polymer film according to the embodiment of the present invention, although it is not limited to a specific method, proton nuclear magnetic resonance spectroscopy ( 1 1H-NMR) and Fourier transform infrared spectroscopy (FT-IR) can be used. Also, if necessary, a plurality of methods can be combined for confirmation.

[0015] As an embodiment of the present invention, a film containing the above polymer (hereinafter, may be referred to as "polymer film" or simply "film") can be mentioned. The film of the present invention is preferably a film that enables ion conduction between the positive electrode and the negative electrode when used as a battery. That is, the film of the present invention is preferably an ion-conductive polymer film. In the present invention, the ion-conductive polymer film means a film having an ion conductivity of 10 -9 S / cm or more. The ion conductivity referred to here means the value measured by the measurement method described later in an environment of 25°C. The upper limit value of the ion conductivity of the film of the present invention is not particularly limited, but is substantially 1.0×10S / cm or less. The ion conductivity is preferably 1.0×10 -7 S / cm or more and 1.0×10S / cm or less, preferably 1.0×10 -6 S / cm or more and 1.0×10S / cm or less, preferably 1.0×10 -5More preferably, it is 1.0×10 S / cm or more and 1.0×10 S / cm or less, and 1.0×10 -4 More preferably, it is 1.0×10 S / cm or more and 1.0×10 S / cm or less, and 2.0×10 -4 More preferably, it is 1.0×10 S / cm or more and 1.0×10 S / cm or less, and 5.0×10 -4 More preferably, it is 1.0×10 S / cm or more and 1.0×10 S / cm or less. By setting the ionic conductivity within the above range, the ionic permeability inside the battery is high, and excellent output characteristics and cycle characteristics can be obtained. When the ionic conductivity is less than 1.0×10 -5 S / cm, the ionic permeability is low, the output characteristics deteriorate, and the capacity degradation becomes large when repeatedly used. In order to set the ionic conductivity within such a range, it is preferable to form a polymer film using the polymer described later. In the embodiment of the present invention, by including this ion-conductive polymer film, ions can be conducted uniformly. Furthermore, since it is possible to prevent cracks and defects in each layer due to the impact during battery use, which is unique to the polymer film, it is possible to suppress short circuits and ignition due to dendrite generation. Due to the above two points, the capacity retention of the battery is improved. Moreover, the interface between the electrode binder layer and the electrolyte layer becomes smooth and the adhesion is improved, so that the interface resistance value becomes small and the battery characteristics are also improved.

[0016] The polymer film of the present invention preferably contains a polymer containing at least one of a thiocarbonyl group, a thiourea group, a thioamide group, and a thiourethane group. By containing the above polymer, the polymer film can achieve both ion conductivity and the performance of blocking the permeation of substances other than the ions. It is considered that this effect is due to the ability to selectively permeate only cations that contribute to battery operation, such as lithium ions, by containing the aforementioned polymer. In particular, it is preferable to contain at least one of a thiourea group, a thioamide group, and a thiourethane group, more preferably to contain at least one of a thiourea group and a thioamide group from the viewpoint of the stability of the chemical structure, and particularly preferably to contain a thiourea group from the viewpoint of lithium ion selective permeability. The method for obtaining the above polymer film is not particularly limited. For example, it is possible by setting the concentration of the solution for forming the polymer film within the range described below.

[0017] As the polymer of the present invention, a polymer having an aromatic ring on the main chain can be preferably used. Examples include aromatic polythioketone, aromatic polythiourea, aromatic polythioamide, aromatic polythiourethane, semi-aromatic polythioketone, semi-aromatic polythiourea, semi-aromatic polythioamide, and semi-aromatic polythiourethane. Also, a blend of a plurality of polymers may be used. Among them, aromatic polythiourea, aromatic polythioamide, aromatic polythiourethane, and semi-aromatic polythiourea are more preferable, and aromatic polythiourea is particularly preferable because it is easy to maintain high strength when thinned. That is, it is preferable that the ion-conductive polymer according to the embodiment of the present invention contains aromatic polythiourea.

[0018] Examples of the aromatic polythiourea and semi-aromatic polythiourea that can be preferably used in the present invention include those having a repeating unit represented by the following chemical formula (1), chemical formula (2), and / or chemical formula (3). Ar in chemical formula (1) 1 , Ar in chemical formula (2) 2 , and Ar 3、 Ar in chemical formula (3) 4is a group containing an aromatic group, and each may be a single group or a multi-component copolymer composed of a plurality of groups. R in Chemical Formula (3) is a non-aromatic structure that does not contain an aromatic ring. By using the above aromatic polythiourea and semi-aromatic polythiourea, the performance of preventing the permeation of substances other than ions contributing to battery operation is improved. Among the following Chemical Formulas (1), (2) and / or (3), Chemical Formulas (1) and (2) are more preferred. Also, the bonds constituting the main chain on the aromatic ring may be either meta-oriented or para-oriented. Further, some of the hydrogen atoms on the aromatic ring may be substituted with any group.

[0019]

Chem.

[0020]

Chem.

[0021]

Chem.

[0022] Specific examples of the aromatic diamines that constitute aromatic polythioureas, aromatic polythioamides, and aromatic polythiourethanes include paraphenylenediamine, metaphenylenediamine, orthophenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2'-bis(trichloromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 2-chloro-1,4-phenylenediamine, 2-trifluoromethyl-1,4-phenylenediamine, 5-trifluoromethyl-1,3-phenylenediamine, 4,'-oxybis(3-trifluoromethyl)aniline, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, 1,5'-naphthalenediamine, 4,4'-diaminodiphenyl sulfone, and the like, but are not limited thereto.

[0023] Specific examples of the non-aromatic diamines include ethylenediamine, propanediamine, butanediamine, pentanediamine, hexamethylenediamine, and the like, but are not limited thereto.

[0024] The permeation rate of the ion-conductive polymer film according to the embodiment of the present invention is preferably 0 or more and 2.0×10 -3 per 100 cc / sec or less. Preferably 0 or more and 5.0×10 -3 per 100 cc / sec or less, more preferably 0 or more and 1.0×10 -4 per 100 cc / sec or less. By making the air permeability less than 2.0×10 -3 per 100 cc / sec, it often has physical through-holes, and the effect of blocking the penetration of dendrites and the like can be obtained. In order to make the air permeability within such a range, it is preferable to form a polymer film using the polymer described later.

[0025] The polymer film of the present invention preferably has a non-porous region. The non-porous region refers to a region where, in the cross-sectional image of the polymer film obtained by field emission scanning electron microscope measurement (FE-SEM) in the measurement method described later, a straight line perpendicular to the interface is drawn from one interface toward the other interface, and the number of voids of 50 nm or more intersecting the straight line is determined, and the region where the number of voids is 10 or less. In the present invention, having a non-porous region means that the thickness of the non-porous region is 0.5 μm or more. When the polymer film is a composite film composed of a non-porous region and a microporous membrane, the point where the distribution and size of voids in the thickness direction start to change is regarded as the interface. By having a non-porous region, the performance of preventing the permeation of substances other than ions contributing to battery operation is improved, and an increase in battery capacity and life becomes possible.

[0026] The polymer film of the present invention preferably has a non-porous region with a thickness of 0.5 μm or more and less than 20 μm. By setting the thickness of the non-porous region to be equal to or less than the above-mentioned upper limit, it is possible to suppress the resistance of the polymer film from becoming too large in battery characteristics, and since the weight can be reduced, it can be suitably used as a battery for a flying object that requires weight reduction. The thickness of the non-porous region is preferably 15 μm or less, more preferably 10 μm or less, and most preferably 5 μm or less. Also, if the thickness of the non-porous region is too small, the cycle life of the battery decreases, so it is preferably 0.6 μm or more, more preferably 0.8 μm or more, and most preferably 1.0 μm or more. The method for setting the thickness of the non-porous region within the above range is not particularly limited. For example, it can be achieved by setting the concentration of the solution for forming the polymer film within the range described later.

[0027] From the perspective of improving ionic conductivity, the polymer film of the present invention preferably has a cation concentration of 1 μmol / g or more. The cation is preferably one or more metal element ions selected from the group consisting of lithium ions, sodium ions, magnesium ions, zinc ions, and aluminum ions. By including one or more metal elements selected from the group consisting of lithium, sodium, magnesium, zinc, and aluminum in the polymer film, the ion mobility increases and the performance of a practical battery can be obtained. The cation concentration is more preferably 30 μmol / g or more, still more preferably 50 μmol / g or more, particularly preferably 100 μmol / g or more, remarkably preferably 500 μmol / g or more, and most preferably 1000 μmol / g or more. When the cation concentration is within the above range and the content of one or more metal elements selected from lithium, sodium, magnesium, zinc, and aluminum is less than 30 μmol / g, sufficient ionic conductivity may not be obtained when used in a secondary battery, and the battery characteristics may be inferior. Although the upper limit of such content is not particularly defined, if it is too much, the handleability will decrease due to moisture absorption, so it is preferably 50000 μmol / g or less, more preferably 10000 μmol / g or less. That is, per 1 g of the polymer constituting the polymer film, the content of one or more metal elements selected from the group consisting of lithium, sodium, magnesium, zinc, and aluminum is preferably 1 μmol / g or more and 50000 μmol / g or less. Note that the above means that the polymer film contains one or more metal elements selected from the group consisting of lithium, sodium, magnesium, zinc, and aluminum, and the content of at least one of the metal elements is within the above range. Or, there may be two or more metal elements whose contents are within the above range among one or more metal elements selected from the group consisting of lithium, sodium, magnesium, zinc, and aluminum. Also, the cation concentration can be evaluated using known methods such as atomic absorption spectrometry and ICP emission analysis. The method for setting the cation concentration within the above range is not particularly limited, and for example, a method of adding a metal salt described later can be mentioned.

[0028] In the polymer film according to an embodiment of the present invention, from the viewpoint of improving ionic conductivity, the lithium ion concentration is preferably 1 μmol / g or more. By including a lithium element having a relatively small atomic weight in the polymer film, particularly when lithium ions are used as a migration medium, the ionic mobility increases and practical battery performance can be obtained. The lithium ion concentration is more preferably 30 μmol / g or more, still more preferably 50 μmol / g or more, particularly preferably 100 μmol / g or more, extremely preferably 500 μmol / g or more, and most preferably 1000 μmol / g or more. When the content of the lithium element is less than 30 μmol / g, sufficient ionic conductivity may not be obtained when used in a secondary battery, and the battery characteristics may be inferior. Although the upper limit of such content is not particularly defined, if it is too large, the handleability may decrease due to moisture absorption, so it is preferably 50000 μmol / g or less, and more preferably 10000 μmol / g or less. That is, the lithium concentration of the polymer film is preferably 1 μmol / g or more and 50000 μmol / g or less. The content of the lithium element can be evaluated using known methods such as atomic absorption spectrometry and ICP emission analysis. The method for setting the lithium ion concentration within the above range is not particularly limited, and examples thereof include a method of adding a metal salt described later.

[0029] The lithium element contained in the polymer film according to an embodiment of the present invention may be added into the polymer film in the state of a lithium salt (Li salt) as an electrolyte. From the viewpoints of thermal and electrochemical stability, the lithium salt is preferably LiPF 6 , LiAsF 6 , LiClO 4 , LiBF 4 , LiBr, lithium trifluoromethanesulfonate, lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(pentafluoroethanesulfonyl)imide, etc., and LiPF 6 , LiClO 4 , LiBF 4, lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide, etc. are particularly preferred. These lithium salts may be used alone or in combination of two or more. Similarly, one or more metal elements selected from the group consisting of sodium, magnesium, zinc, and aluminum contained in the polymer film in the embodiment of the present invention may also be added into the polymer film in the state of a salt as an electrolyte.

[0030] The polymer film in the embodiment of the present invention preferably contains at least one of bis(trifluoromethanesulfonamide) ion, bis(fluorosulfonamide) ion, trifluoromethanesulfonate ion, PF 6 ion, ClO 4 ion, BF 4 ion. By containing the above ions, the number of dissociated cations in the film is improved, and the polymer film exhibits good ionic conductivity.

[0031] The anion in the ion-conductive polymer film according to the embodiment of the present invention preferably has an association constant with the polymer of 1.0 M -1 or more and 1.0×10 10 M -1 or less, more preferably 5.0 M -1 or more and 1.0×10 10 M -1 or more and 1.0×10 1 M -1 or more and 1.0×10 10 M -1 or more and 1.0×10 2 M -1 or more and 1.0×10 10 M -1It is particularly preferable that it is within the above range. By being within the above range, dissociation of the electrolyte salt contained in the polymer is promoted, and at the same time, the cation transport rate is improved, thereby improving the battery life and capacity. The above association constant represents the strength of the interaction between the polymer and the anion. In the combination of a polymer and an anion with a high binding constant, the conduction of the anion, which is a factor in battery side reactions, is inhibited. The association constant with the polymer can be measured by NMR described later. The method for setting the association constant with the polymer within the above range is not particularly limited, but for example, it is preferable to form a polymer film using the polymer and the Li salt described later.

[0032] The weight concentration of the Li salt contained in the polymer ion conductive film in the embodiment of the present invention is preferably 0 wt% or more and 80 mass% or less, more preferably 10 wt% or more and 60 mass% or less, and particularly preferably 20 wt% or more and 40 mass% or less. By being 0 wt% or more, the ionic conductivity is improved. On the other hand, by being 80 wt% or less, the film strength becomes good. The method for setting the Li salt weight concentration within the above range is not particularly limited, but for example, the method for forming the polymer ion conductive film described later can be used to change the metal salt concentration.

[0033] The haze of the polymer film of the present invention is preferably 0% or more and 30% or less, more preferably 0% or more and 10% or less, still more preferably 0% or more and 5% or less, and particularly preferably 0% or more and 1% or less. By being within the above range, a uniform film can be obtained, and good ionic conductivity and electrolyte blocking performance are exhibited. The method for setting the haze within the above range is not particularly limited, but for example, it is preferable to form a polymer film using the polymer described later.

[0034] In the polymer film according to an embodiment of the present invention, the cation transference number is preferably 0.5 or more and 1.0 or less, more preferably 0.6 or more and 1.0 or less, still more preferably 0.7 or more and 1.0 or less, and even more preferably 0.8 or more and 1.0 or less. By the cation transference number being within the above range, side reactions in the battery and a decrease in liquid separability can be suppressed, and good battery characteristics can be exhibited. The cation transference number can be evaluated using known methods using the alternating current impedance method and the direct current method.

[0035] The electrode in the battery according to an embodiment of the present invention may contain the same polymer as the polymer film. By the electrode containing the same ion-conductive polymer, the interfacial resistance between layers can be reduced, the ion conductivity and cycle characteristics can be improved dramatically, and the battery characteristics can be enhanced.

[0036] The polymer film of the present invention may contain other components that serve as ion conduction aids as long as the effects of the present invention are not inhibited. Examples include inorganic solid electrolytes, ionic liquids, and lithium salts.

[0037] The polymer film of the present invention preferably has a film thickness change rate (T0 / T1) measured under the conditions described below of 0.3 or more and less than 1.0.

[0038] (Measurement conditions for film thickness change rate) The polymer film was immersed in a non-aqueous electrolyte (1M LiTFSI EC / DEC = 1 / 1, manufactured by Mitsui Chemicals, Inc.) at 25°C for 24 hours, and the thickness of the polymer film before and after immersion was measured with a high-precision digital length measuring instrument (manufactured by Mitutoyo Corporation, model number: VL-50), and substituted into equation (1) for calculation. Film thickness change rate = (T0 / T1) (1) T0: Thickness of the polymer film before immersion in the non-aqueous electrolyte (cm) T1: Thickness of the polymer film after immersion in the non-aqueous electrolyte (cm).

[0039] When the film thickness change rate is 0.3 or more, it is possible to suppress a decrease in the strength of the polymer film inside the battery, and the dendrite resistance is excellent. When it is less than 1.0, the polymer film inside the battery has excellent ion conductivity. More preferably, it is 0.3 or more and 0.9 or less. In order to make the film thickness change rate within such a range, the polymers described below can be used as the polymer constituting the polymer film.

[0040] The polymer film of the present invention preferably has a non-porous region and a microporous membrane, and particularly preferably is a composite membrane having a non-porous region and a microporous membrane. The method for forming the composite membrane is not particularly limited, but for example, a method of applying an ion-conductive polymer to at least one side of the microporous membrane by the method described below can be exemplified. Examples of the microporous membrane include a porous membrane having pores inside, a non-woven fabric, or a porous membrane sheet made of a fibrous material. The material constituting the microporous membrane is preferably composed of a resin that has electrical insulation, is electrically stable, and is also stable in a non-aqueous electrolyte. Further, from the viewpoint of imparting a shutdown function, the resin used is preferably a thermoplastic resin having a melting point of 200°C or lower. The shutdown function here refers to a function of closing the porous structure by melting with heat and stopping ion movement and power generation when the lithium-ion battery generates abnormal heat.

[0041] Examples of the thermoplastic resin include polyolefin-based resins. The microporous membrane is preferably a polyolefin-based microporous membrane, and more preferably has a melting point of 200°C or lower. Specific examples of the polyolefin-based resin used for the microporous membrane include polyethylene, polypropylene, copolymers thereof, and mixtures thereof. Examples include a single-layer microporous membrane containing 90% by mass or more of polyethylene, and a multi-layer microporous membrane composed of polyethylene and polypropylene.

[0042] The polymer film of the present invention preferably has a heat shrinkage rate of 10% or less at 150 °C determined by the method described below. Further, it is preferable that both the longitudinal direction (MD) and the width direction (TD) of the polymer film are 10% or less, more preferably 8% or less, and most preferably 5% or less. The lower limit is not particularly limited, but is -1% or more. By setting the heat shrinkage rate of either MD or TD within the above range, it is possible to suppress the occurrence of a short circuit at the battery end due to dimensional changes of the polymer film during battery heating, and a battery with excellent heat resistance can be obtained. In order to keep the heat shrinkage rate within the above range, it is preferable to use a polymer having the above-described molecular structure and set the production conditions of the polymer film within the range described below.

[0043] It is preferable that at least one of the positive electrode and the negative electrode of the present invention is in proximity to the polymer film. The ion-conductive polymer of the present invention is a polymer that enables ion conduction between the positive electrode and the negative electrode. By having at least one of the positive electrode and the negative electrode in proximity to the polymer layer, the ion conductivity between the layers is improved, and by being in proximity to at least one of the electrodes, it is possible to suppress short circuits and ignition due to dendrite generation during battery use. Here, having in proximity means having within 1 μm, and it may be in direct contact or via other layers.

[0044] A method for obtaining the polymer according to an embodiment of the present invention will be described by taking aromatic polythiourea and semi-aromatic polythiourea as examples, but the polymers that can be used and their polymerization methods are not limited thereto.

[0045] Although various methods are available for obtaining aromatic polythiourea, for example, when using dithioisocyanate and diamine, thiophosgene and diamine, or 1,1'-thiocarbonyldiimidazole and diamine as raw materials and the low-temperature solution polymerization method, it is synthesized in an aprotic organic polar solvent such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, dimethylformamide, or dimethyl sulfoxide. In the case of solution polymerization, in order to obtain a polymer with a high molecular weight, it is preferable that the water content of the solvent used for polymerization be 500 ppm or less (mass basis, the same hereinafter), and more preferably 200 ppm or less. Further, a metal salt may be added for the purpose of promoting polymer dissolution. As this metal salt, a halide of an alkali metal or alkaline earth metal that dissolves in an aprotic organic polar solvent is preferable, and examples include lithium chloride, lithium bromide, sodium chloride, sodium bromide, potassium chloride, and potassium bromide. Since using equal amounts of both the dithioisocyanate and diamine used may produce a polymer with an ultra-high molecular weight, it is preferable to adjust the molar ratio so that one is 95.0 to 100.0 mol% of the other. In the case of the reaction between dithioisocyanate and diamine, a basic compound may be added to increase the degree of polymerization, and examples include imidazole, triethylamine, and pyridine.

[0046] The reduced viscosity ηinh of the polymer is preferably 0.3 to 7.0 dl / g. By setting the viscosity within the above range, a polymer excellent in toughness and strength and having good ionic conductivity can be obtained. The viscosity η can be measured, for example, by the method described later.

[0047] Next, the casting solution (hereinafter referred to as the casting solution) used when manufacturing the electrode mixture layer and the electrolyte layer according to the embodiment of the present invention will be described.

[0048] As one aspect of the battery according to an embodiment of the present invention, examples include those in which a current collector layer on the positive electrode side, an electrode mixture layer containing a positive electrode active material (which may be referred to as a positive electrode layer), an electrolyte layer, an electrode mixture layer containing a negative electrode active material (which may be referred to as a negative electrode layer), and a current collector layer on the negative electrode side are laminated in this order or in the reverse order. Also, a battery can be assembled using known battery components.

[0049] The polymer of the present invention is not only used as the electrolyte layer in the above-described battery as a polymer film, but may also be included in either the electrode mixture layer of the positive electrode layer or the negative electrode layer, or may be included in both layers. Further, an ion-conductive polymer may be applied to the surface of the positive electrode layer or the negative electrode layer to serve as both a protective film for the electrode surface and the function of the electrolyte layer.

[0050] As one aspect of the present invention, there is provided a solution containing a polymer in which the atomic number density of atoms having a charge density of -1.0 or more and -0.5 or less is 0% or more and 7% or less, and the atomic number density of atoms having a charge density of 0.25 or more and 1.0 or less is 5% or more and 100% or less. By forming a polymer film using the polymer solution containing the above polymer, a polymer film excellent in ion conductivity and the performance of blocking the permeation of substances other than the ions can be obtained.

[0051] The polymer solution after polymerization may be used as it is as the stock solution for film formation, but it is preferable to add a Li salt to the polymerization solution from the viewpoint of improving the ionic conductivity. When a large amount of unnecessary substances such as neutralization salts are contained, it is preferable to isolate the polymer once and then redissolve it in an organic solvent such as the above-mentioned aprotic organic polar solvent for use. The method for isolating the polymer is not particularly limited, and examples include a method in which the polymer solution after polymerization is poured into a large amount of water or alcohol to extract the solvent and the neutralization salt into the water, separating only the precipitated polymer, and then drying it.

[0052] In the manufacturing process of the electrode binder layer and the electrolyte layer according to the embodiment of the present invention, it is preferable to add an active material, an inorganic solid electrolyte, a conductive auxiliary, a lithium salt, etc. to the ion-conductive polymer. There is no limitation on the timing of adding these materials, and any of the polymer polymerization process, the casting solution preparation process, and the casting process may be used. However, it is preferable to add them in the casting solution preparation process because they can be uniformly dispersed with the polymer. Also, it is possible to add them in a plurality of steps, or to add them in multiple portions in the same step.

[0053] The concentration of the polymer in the casting solution is preferably 3 to 30% by mass, more preferably 4 to 20% by mass. Inorganic particles or organic particles may be added to the casting solution within a range that does not inhibit the effects of the present invention for the purpose of improving the strength, heat resistance, ion permeability, and reducing the coefficient of static friction of the resulting polymer film. Examples of the inorganic particles include wet and dry silica, colloidal silica, aluminum silicate, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, aluminum hydroxide, magnesium hydroxide, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide (zinc white), antimony oxide, cerium oxide, zirconium oxide, tin oxide, lanthanum oxide, magnesium oxide, barium carbonate, zinc carbonate, basic lead carbonate (lead white), barium sulfate, calcium sulfate, lead sulfate, zinc sulfide, mica, mica titanium, talc, clay, kaolin, lithium fluoride, and calcium fluoride. Examples of the organic particles include particles crosslinked using a polymer compound as a crosslinking agent. Examples of such crosslinked particles include crosslinked particles of a polymethoxysilane-based compound, a polystyrene-based compound, an acrylic-based compound, a polyurethane-based compound, a polyester-based compound, a fluorine-based compound, or a mixture thereof.

[0054] Next, a method for forming the polymer film of the present invention will be described. The casting solution prepared as described above can be cast by a so-called solution casting method. The solution casting method includes a dry-wet method, a dry method, a wet method, etc., and any method can be used for casting. Here, the dry-wet method will be described as an example.

[0055] When forming a film by the dry-wet method, the film-forming stock solution is extruded from a die onto a support such as a drum, endless belt, or film to form a film-like material, and then the film-like material is dried until it has self-supporting properties. The drying conditions can be, for example, in the range of 60 to 220°C for 60 minutes or less. However, the film after the dry process is peeled off from the support and introduced into the wet process, where desalting, solvent removal, etc. are performed, and stretching, drying, and heat treatment are performed as necessary.

[0056] When stretching, the stretching ratio is preferably in the range of 0.8 to 8.0 times in terms of area ratio (the area ratio is defined as the value obtained by dividing the area of the film after stretching by the area of the film before stretching. A value of 1 or less means relaxation), and more preferably 1.0 to 5.0 times. Also, when heat-treating, the heat treatment is carried out at a temperature of 80°C to 500°C, preferably 130°C to 400°C, for several seconds to several tens of minutes. The polymer film of the present invention obtained by the above production method can be used as an electrolyte membrane by being inserted directly between the positive and negative electrodes.

[0057] When the polymer film of the present invention is made into a composite membrane having a non-porous region and a microporous membrane, the polymer film and the microporous membrane obtained by the above-described film-forming method may be used by overlapping them, or they may be laminated. Also, a method of applying and laminating the film-forming stock solution polymerized above onto the microporous membrane is also preferable. As a form of applying the stock solution onto the microporous membrane, any application form such as a roll coater, slit coater, or dip coater can be used.

[0058] The thickness of the polymer film according to the embodiment of the present invention is not particularly limited, but is preferably 0.03 to 30 μm, more preferably 0.10 to 20 μm, and even more preferably 0.20 to 15 μm. Further, when the polymer film of the present invention is a composite film of a polymer film and a microporous film, the thickness ratio of the polymer film to the microporous film is preferably 0.001 or more and 5 or less, and more preferably 0.01 or more and 1 or less. By setting the thickness within the above range, the strength of the polymer film is sufficient, there is no increase in resistance due to the film thickness, and it can be suitably used. The thickness of the polymer film can be controlled by various conditions such as the concentration of the casting solution, the viscosity of the casting solution, the type and concentration of additives in the casting solution, the casting thickness of the polymer film, the heat treatment temperature, and the stretching conditions.

[0059] The battery according to the embodiment of the present invention preferably contains the polymer film of the present invention. As one aspect of the battery of the present invention, there is an example in which the polymer film obtained by the above-described film-forming method is disposed between the positive electrode and the negative electrode to form a battery. Further, any method can be used as the method for manufacturing the battery. By including the polymer film, the crossover of side reaction products generated at the electrodes between the electrodes and the generation of dendrites at the negative electrode are suppressed, and the life and capacity of the battery are improved.

[0060] From the viewpoint of energy density, the battery according to the embodiment of the present invention is preferably a metal Li negative electrode battery, a silicon negative electrode battery, a clay battery, a sulfur battery, or an air battery. Among sulfur batteries, a lithium-sulfur battery is more preferable. Among air batteries, an aluminum air battery, a zinc air battery, a hydrogen air battery, and a lithium air battery are more preferable, and a lithium air battery is particularly preferable.

[0061] The battery according to an embodiment of the present invention has a positive electrode, an electrolyte, a polymer film, an electrolyte, and a negative electrode in this order, and is preferably composed of electrolytes with different compositions on the positive electrode side and the negative electrode side via the polymer film. With the above configuration, decomposition of the electrolyte can be suppressed, leading to an increase in the capacity and a longer life of the battery. Further, in the above battery configuration, it is preferable that at least one of the electrolytes on the electrode side contains water. In particular, when the positive electrode is an air electrode, it is preferable that the electrolyte on the positive electrode side contains water. It is possible to suppress the precipitation of lithium oxide on the surface of the positive electrode and improve the life of the battery.

[0062] The positive electrode of the battery according to an embodiment of the present invention contains a known positive electrode active material such as a lithium metal oxide (such as lithium cobaltate or lithium manganate) containing at least one transition metal selected from manganese, cobalt, nickel, and titanium and lithium as the positive electrode active material. Further, an air electrode may be used as the positive electrode. From the viewpoint of energy density, it is preferable to use an air electrode.

[0063] The negative electrode of the present invention is not particularly limited as long as it is a material capable of occluding and releasing metal ions or the like as an active material. For example, known negative electrode active materials such as Li, Sn, Si, In, lithium alloy particles (lithium alloy particles of lithium and titanium, magnesium, aluminum, etc.), and carbon-based materials (carbon, hard carbon, soft carbon, and graphite, etc.) can be appropriately used. Among them, using metallic lithium is preferable from the viewpoint of increasing the energy of the battery. Further, the lithium-equivalent concentration of the negative electrode is preferably 1.0 mol / l or more of the entire negative electrode. If the lithium-equivalent concentration is 1.0 mol / l or more, a high capacity can be achieved. The upper limit is not particularly limited, but is substantially 100 mol / l or less.

[0064] The non-aqueous electrolyte of the present invention can use organic solvents that are conventionally used in lithium-ion batteries without particular limitation. Also, the electrolyte to which the present invention is applied can be either solid or liquid, but it is preferable to use an electrolytic solution in order to increase the contact area with the electrodes. As the solvent of the above electrolytic solution, cyclic esters, chain esters, cyclic ethers, chain ethers, etc. are used. Specifically, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), γ-butyrolactone (γBL), 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane (DME), 1,2-ethoxyethane, diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, tetraethylene glycol dialkyl ether, dipropyl carbonate, methyl butyl carbonate, methyl propyl carbonate, ethyl butyl carbonate, ethyl propyl carbonate, butyl propyl carbonate, alkyl propionate, dialkyl malonate, alkyl acetate, tetrahydrofuran (THF), alkyl tetrahydrofuran, dialkyl alkyl tetrahydrofuran, alkoxy tetrahydrofuran, dialkoxy tetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, 1,4-dioxolane, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, methyl propionate, ethyl propionate, triester phosphate, N-methyl-2-pyrrolidone, sulfolane and other organic solvents, water, and derivatives and mixtures thereof are preferably used.

[0065] As the electrolyte contained in the non-aqueous electrolyte solution, halides, perchlorates, thiocyanates, borofluorides, phosphofluorides, arsenofluorides, aluminum fluorides, trifluoromethyl sulfates, etc. of alkali metals, particularly lithium, are preferably used. For example, lithium perchlorate (LiClO 4 ), lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), lithium bis(trifluoromethylsulfonyl)imide [LiN(CF 3 SO 2 ) 2 , lithium bromide (LiBr), lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium bis(pentafluoroethanesulfonyl)imide, etc., one or more salts such as lithium salts (electrolytes) can be used, but lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide (LiFSI) are preferred.

[0066] In the non-aqueous electrolyte of the battery according to the embodiment of the present invention, it contains at least one kind of metal ion, and the concentration of the metal ion is preferably 0.5 mol / l or more and 7.0 mol / l or less. The metal ion is preferably a metal ion that moves between the positive electrode and the negative electrode when the battery is charged and discharged. Specifically, in the case of a lithium-ion battery, it is a lithium ion, and in the case of a sodium battery, it is a sodium ion. The concentration of the metal ion is preferably 0.5 mol / l or more and 5.0 mol / l or less, more preferably 1.0 mol / l or more and 5.0 mol / l or less. By being within the above range, the battery exhibits good battery characteristics. From the viewpoint of the operability of the battery, the metal ion is preferably a lithium ion, a sodium ion, a magnesium ion, a potassium ion, or a calcium ion, more preferably a lithium ion, a sodium ion, or a magnesium ion, and particularly preferably a lithium ion. Further, an additive may be used in the non-aqueous electrolyte as needed. Examples of the additive include vinylene carbonate, fluoroethylene carbonate, ethylene sulfite, 1,4-butane sultone, propane sultone, 2,4-difluoroanisole, biphenyl, cyclohexylbenzene, etc., and one or more of these may be used.

[0067] For the battery according to the embodiment of the present invention, the weight ratio of the electrolyte to the film contained in the battery (weight of the electrolyte / weight of the film) is preferably 0 or more and 5 or less, more preferably 0 or more and 1 or less, still more preferably 0 or more and 0.5 or less, and particularly preferably 0 or more and 0.2 or less. By setting the weight ratio of the electrolyte to the film within the above range, the weight energy density of the battery can be improved.

[0068] Next, the manufacturing method of the battery according to the embodiment of the present invention will be described below.

[0069] The material used as the current collector layer in the battery according to the embodiment of the present invention is not particularly limited. For example, a metal foil made of gold, silver, aluminum, copper, stainless steel, nickel, titanium, alloys thereof, carbon-based materials, etc. can be used.

[0070] The electrode mixture layer of the positive electrode of the battery according to the embodiment of the present invention may be a single substance or may contain other components. As other components, known positive electrode active materials such as at least one transition metal selected from manganese, cobalt, nickel, and titanium and a lithium metal oxide containing lithium (such as lithium cobaltate and lithium manganate) can be appropriately used. Further, for the electrode mixture layer of the negative electrode, the active material is not particularly limited as long as it is a material capable of occluding and releasing metal ions, etc. For example, known negative electrode active materials such as Li, Sn, Si, In, lithium alloy particles (lithium alloy particles of lithium and titanium, magnesium, aluminum, etc.), and carbon-based materials (carbon, hard carbon, soft carbon, graphite, etc.) can be appropriately used.

[0071] The electrode composite according to the embodiment of the present invention preferably has the above film and the electrode in proximity. The above film of the present invention is a polymer that enables ion conduction between the positive electrode and the negative electrode. When at least one of the positive electrode and the negative electrode is in proximity to the polymer layer, the ion conductivity between the layers is improved, and when in proximity to at least one of the electrodes, short circuits and ignition due to dendrite generation during battery use can be suppressed. Here, having in proximity means having within 1 μm, and it may be in direct contact or may be via other layers. Examples of the method of bringing the electrode and the ion-conductive polymer film into proximity include a method using roll pressing and a method of applying a solution containing the ion-conductive polymer film to the electrode and drying it.

[0072] The battery according to the embodiment of the present invention can be suitably used as a power source for electronic devices such as mobile phones and watches, vehicles such as electric vehicles (EVs), hybrid vehicles (HEVs), plug-in hybrid vehicles (PHEVs), airplanes, urban air mobility (UAM), unmanned transporters such as drones, unmanned aircraft such as high-altitude pseudo-satellites (HAPS), and large industrial equipment such as industrial cranes. It can also be suitably used for power leveling in solar cells, wind power generation devices, etc., energy storage devices for smart grids, and stationary power supplies. Furthermore, it can be suitably used for batteries used in special environments such as space applications.

Examples

[0073] The present invention will be described in more detail with the following examples. The physical properties of the examples were measured by the following methods.

[0074] (1) Charge density Using the quantum chemical calculation program Gaussian16 (manufactured by Gaussian), density functional theory calculations were performed. The functional and basis functions were calculated using B3LYP and 6-31G(d,p). Electrostatic potential charge fitting was performed using points based on the CHelpG scheme to calculate the charge density of each atom. The above procedure was performed three times with the same structure, and the average value was taken as the charge density of each atom. For polymers, calculations were performed using a trimer of the repeating structure, and each atom of the central repeating structure was taken as the charge density of the atoms in the polymer.

[0075] (2) Inherent viscosity ηinh The polymer was dissolved in N-methylpyrrolidone (NMP) containing 2.5 mass% lithium bromide (LiBr) at a concentration of 0.5 g / dl, and the flow-down time was measured at 30 °C using an Ubbelohde viscometer. The flow-down time of the blank LiBr 2.5 mass% / NMP without dissolving the polymer was also measured in the same way, and the inherent viscosity ηinh (dl / g) can be obtained by calculating using the following formula.

[0076] Inherent viscosity ηinh (dl / g) = [ln(t / t0)] / 0.5 t0: Flow-down time of the blank (seconds) t: Flow-down time of the sample (seconds).

[0077] (3) Permeation rate Measurement was carried out with the setting of 100 cc of air volume using the Wang Research Permeability Tester (manufactured by Asahi Seiko Co., Ltd., EGO-1T). The measurement upper limit of the apparatus is 10,000 seconds / 100 cc. The polymer film was fixed so as not to have wrinkles and measured in accordance with JIS P8117:2009. The measurement points were set at three points at equal intervals in the TD direction, and the reciprocal of the average value of the permeability was used as the permeation rate (100 cc / second).

[0078] (4) Cross-sectional structure (thickness of the polymer film, thickness of the non-porous region) The polymer film obtained in the example was subjected to cross-section cutting using a cross-section polisher (SM-9010 manufactured by JEOL Ltd.), and a platinum coat was applied to the cross-section in the thickness direction in the width direction to obtain an observation sample. Next, using a field emission scanning electron microscope (FE-SEM) (JSM 6701F manufactured by JEOL Ltd.), the cross-section of the sample was photographed at an arbitrary magnification to determine the thickness of the polymer film. The acceleration voltage during observation was set to 2.0 kV. When the polymer film is a composite film, the interface between the non-porous layer and the microporous layer was determined from the difference in cross-sectional structure or image contrast, and the respective thicknesses were determined. Next, from the image taken at 10,000 times magnification, the thickness of the non-porous region was determined by the following method. A straight line perpendicular to the interface was drawn from one interface of the polymer film to the other interface, and the number of voids of 50 nm or more intersecting the straight line was determined. If the number of voids was 10 or less, it was determined as the non-porous region, and the thickness was determined. When the polymer film is a composite film composed of a non-porous region and a microporous film, the point where the distribution and size of the voids in the thickness direction began to change was regarded as the interface.

[0079] (5) Glass transition temperature Using DMA, DMS6100 (manufactured by Seiko Instruments Inc.), measurement was carried out in the MD direction of the film of the polymer alone under the following conditions, and the maximum value of tan δ was taken as the glass transition temperature.

[0080] Frequency: 1 Hz Measured temperature: 25°C to 420°C Heating rate: 5°C / min Strain amplitude: 10 μm Minimum tension: 200 mN Initial value of force amplitude: 400 mN (6) Cation concentration Using an atomic absorption spectrometer, the cation concentration in the polymer film was determined. 0.1 g of the sample was weighed, sulfuric acid was added, and after heating and carbonizing, it was heated and ashed. The ash was decomposed by heating with sulfuric acid and hydrofluoric acid, and dissolved by warming with dilute nitric acid to make a constant volume. The cation elements in this solution were measured by atomic absorption spectrometry, the content in the sample was determined, and it was converted to the cation element content per 1 g of the separator. When the sample was a laminate, only the electrolyte layer was peeled off and measured.

[0081] Apparatus: Atomic absorption spectrometer (Z-2300 manufactured by Hitachi High-Tech Science Corporation) (7) Ionic conductivity After immersing the polymer film in a non-aqueous electrolyte (1 M LiTFSI ethylene carbonate (EC) / diethyl carbonate (DEC) = 1 / 1) for 24 hours, it was placed on a SUS304 electrode so as to cover the electrode part. After dropping the non-aqueous electrolyte, it was sandwiched with another SUS electrode to prepare a laminate of electrode / polymer film / electrode. An evaluation cell was prepared by fixing it with a silicon plate so that the laminate did not shift.

[0082] For the prepared cell, the alternating current impedance was measured at 25°C with an electrochemical test apparatus (manufactured by Biologic, model number: SP-150) under the conditions of an amplitude of 10 mV and a frequency of 1 MHz - 10 mHz, the resistance value was read from the graph plotted on the complex plane, substituted into equation (2), and the ionic conductivity was calculated. It was measured 5 times, and the calculated average value was taken as the ionic conductivity. σ = T0 / AR (2) σ: Ionic conductivity (S / cm) T0: Thickness of the polymer film (cm) A: Area of the electrode (cm 2 ) R: Resistance value (Ω).

[0083] (8) Cation transport rate Using an HS cell (manufactured by Takizawa Co., Ltd.), metallic Li, the polymer film to be tested, and metallic Li were laminated under an argon atmosphere (oxygen concentration of 0.1 ppm or less, dew point of -75°C or less), and 300 μL of 1 M LiTFSI EC / DEC = 1 / 1 (volume ratio) was injected and sealed. For the fabricated cell, AC impedance was measured at 25°C using an electrochemical test apparatus (manufactured by Biologic, model number: SP-150) under the conditions of an amplitude of 10 mV and a frequency of 1 MHz - 100 mHz, and the interfacial resistance (R 0 ) was calculated from the second arc in the Nyquist plot. Next, the DC resistance of the electrode interface was measured, a DC voltage (V) was applied, and the current values of the initial current value (I 0 ) and the steady state (I 1 ) were measured. Finally, AC impedance was measured at 25°C using an electrochemical test apparatus (manufactured by Biologic, model number: SP-150) under the conditions of an amplitude of 10 mV and a frequency of 1 MHz - 100 mHz, and the interfacial resistance (R 1 ) was calculated from the second arc in the Nyquist plot. The lithium transport rate (τ) was calculated from each of the obtained values using the following equation.

[0084]

Equation

[0085] (9) Haze Measured using the following measuring instrument.

[0086] Apparatus: Direct-reading haze meter HGM-2DP (for C light source) (manufactured by Suga Test Instruments Co., Ltd.) Light source: Halogen lamp 12V, 50W Light reception characteristics: 395 - 745 nm Optical conditions: Conform to JIS-K7105-1981.

[0087] (10) Association constant The polymer concentrations were 0.50 mass% and 0.25 mass%, and the Li salt concentrations of the target anions were 0 mass%, 0.01 mass%, 0.10 mass%, and 0.50 mass% in a total of 8 points of heavy DMSO (dimethyl sulfoxide) solutions.1 1H-NMR measurement was performed. 1 All the measuring devices for 1H-NMR measurement used JNM-EZ400R (manufactured by JEOL Ltd.). Incidentally, 1 For the measurement conditions of 1H-NMR measurement, the number of integration times was 32 times and the relaxation time was 5 seconds. Next, the concentrations of the thiourea group, thioamide group, and thiourethane group of the polymer contained in the solution, the salt concentration, and the chemical shift change values corresponding to the N-H groups of each functional group were used as variables and substituted into the program "COMPLEX2MULTIFIT" for calculation, and the association constants between each functional group and the salt were determined. The average association constant weighted by the molar ratio of the association constants between each functional group and the salt was defined as the association constant.

[0088] (11) Liquid separability In an Ar atmosphere, using a two-chamber cell (SB-100B manufactured by EASY FLON FRONTIER), after separating the two chambers with a polymer film, 1.5 mL of an organic electrolyte solution (4.5 M LiFSI in diethoxyethane) was injected into one chamber. Then, 1.5 mL of an aqueous electrolyte solution (1 M LiCl in 10LiCl aqueous solution) was injected into the other chamber under a dry room atmosphere to prepare an evaluation cell. 24 hours after cell preparation, 200 μL of the organic electrolyte was sampled, and its water content was measured with a Karl Fischer moisture meter.

[0089] ◎: 1.0% or less and 0% or more ○: Less than 4.0% and 1.0% or more △: Less than 5.0% and 4.0% or more ×: 5.0% or more.

[0090] (Example 1) Polymer solution P1 To dehydrated NMP (N-methyl-2-pyrrolidone, manufactured by Mitsubishi Chemical Corporation), 4,4'-diaminodiphenyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) as a diamine was dissolved under a nitrogen stream. Then, 1,4-phenylenedithioisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) corresponding to 100 mol% based on the total amount of diamine was added thereto over 5 min under a nitrogen stream in the system. After the addition of the total amount, stirring was performed for about 7 hours to polymerize aromatic polythiourea (polymer p-1). The inherent viscosity ηinh of the obtained polymer was 1.1 dl / g. Next, this polymer solution was poured into ethanol at a mass ratio of 10 times or more, and the solvent and unreacted substances were extracted into ethanol. After separating only the precipitated polymer, it was vacuum-dried at 60 °C for 10 hours to obtain polymer powder. Thereafter, the ratio of the polymer powder to the lithium salt LiTFSI (lithium bis(trifluoromethanesulfonyl)imide) was 70:30 by mass ratio, and it was redissolved in dehydrated DMSO (manufactured by Fujifilm Wako Pure Chemical Corporation) so that the polymer concentration became 12% by mass to obtain polymer solution P1.

[0091] (Example 2) Polymer solution P2 Except that hexamethylenediamine (manufactured by Fujifilm Wako Pure Chemical Corporation) was used instead of 4,4'-diaminodiphenyl ether and DMAc (dimethylacetamide) (manufactured by Fujifilm Wako Pure Chemical Corporation) was used as the solvent instead of DMSO, the procedure was the same as in Example 1 to obtain polymer solution P2.

[0092] (Example 3) Polymer solution P3 Except that LiClO 4 (manufactured by Fujifilm Wako Pure Chemical Corporation) was used as the lithium salt instead of LiTFSI, the procedure was the same as in Example 1 to obtain polymer solution P3.

[0093] (Example 4) Polymer solution P4 Except that the ratio of the polymer powder to the lithium salt was 85:15 by mass ratio, the procedure was the same as in Example 3 to obtain polymer solution P4.

[0094] (Example 5) Polymer Solution P5 A polymer solution P5 was obtained in the same manner as in Example 1, except that LiBr (manufactured by Fujifilm Wako Pure Chemical Corporation) was used instead of LiTFSI as the lithium salt.

[0095] (Comparative Example 1) Polymer Solution P6 4,4'-Diaminodiphenyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) as a diamine was dissolved in dehydrated NMP (N-methyl-2-pyrrolidone, manufactured by Mitsubishi Chemical Corporation) under a nitrogen stream and cooled to 30°C or lower. Then, while maintaining the system under a nitrogen stream at 30°C or lower, 2-chloroterephthaloyl chloride (manufactured by Nippon Light Metal Co., Ltd.) corresponding to 99 mol% based on the total amount of diamine was added over 30 min. After the addition of the total amount, stirring was carried out for about 2 hours to polymerize an aromatic polyamide (polymer p-3). The obtained polymerization solution was neutralized with lithium carbonate (manufactured by Honjo Chemical Co., Ltd.) at 97 mol% and diethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) at 6 mol% based on the total amount of acid chloride to obtain a polymer solution. The viscosity ηinh of the obtained polymer was 2.6 dl / g. Next, this polymer solution was poured into purified water at a mass ratio of 10 times or more, and the solvent and neutralization salt were extracted into water. After separating only the precipitated polymer, it was vacuum-dried at 100°C for 10 hours to obtain a polymer powder. Then, the ratio of the polymer powder to the lithium salt LiTFSI (lithium bis(trifluoromethanesulfonyl)imide) was 70:30 by mass ratio, and it was redissolved in dehydrated NMP (manufactured by Mitsubishi Chemical Corporation) so that the polymer concentration was 9 mass% to obtain a polymer solution P6.

[0096] (Example 6) Polymer Film F1 The polymer solution P1 was cast on a PET film as a support and dried at a hot air temperature of 120°C until the polymer film had self-supporting properties. After removing the polymer film from the PET, vacuum drying was carried out at a temperature of 120°C, 200 Pa, for 1 hour to obtain a polymer film.

[0097] (Example 7) Polymer Film F2 The polymer solution P2 was cast onto glass as a support and dried by vacuum drying at 90 °C, 200 Pa for 20 minutes until it became self-supporting. Next, vacuum drying was carried out at 90 °C, 200 Pa for 5 hours to obtain a polymer film.

[0098] (Example 8) Polymer film F3 A polymer film was obtained in the same manner as in Example 7, except that P3 was used instead of P2 for the polymer solution.

[0099] (Example 9) Polymer film F4 The polymer solution P4 was cast onto glass as a support and dried by vacuum drying at 90 °C, 200 Pa until it became self-supporting. Next, after removing the polymer film from the glass, vacuum drying was carried out at 90 °C, 200 Pa for 5 hours to obtain a polymer film.

[0100] (Example 10) Polymer film F5 A polymer film was obtained in the same manner as in Example 9, except that P5 was used instead of P4 for the polymer solution.

[0101] (Comparative Example 2) Polymer film F6 The polymer solution P6 was cast onto PET as a support and dried by drying at 130 °C under normal pressure until it became self-supporting. Next, after removing the polymer film from the glass, vacuum drying was carried out at 130 °C, 200 Pa for 1 hour to obtain a polymer film.

[0102] (Comparative Example 3) Polymer film F7 A polyethylene porous membrane (manufactured by Toray Industries, Inc., thickness 5 μm, air permeability 110 seconds / 100 cc) was used.

[0103] (Examples 11, 12, Comparative Example 4) Using an HS cell (manufactured by Takizawa Co., Ltd.), metallic Li, the polymer film described in Table 3, and metallic Li were laminated under an argon atmosphere (oxygen concentration of 0.1 ppm or less, dew point of -75 °C or less), and 300 μL of 1 M LiTFSI EC / DEC = 1 / 1 (volume ratio) was injected and sealed. For the fabricated cell, after performing a preliminary operation test with a current density of 0.1 mA / cm 2 for 1 hour each for charge and discharge and for 3 cycles, a cycle test was performed at each current density and charge / discharge time described in Table 3, and the number of cycles at the point when the applied voltage became 250 mV or more and 20 mV or less was recorded. The weight ratio of the electrolytic solution to the film was calculated by measuring the weight of the polymer film and the amount of the electrolytic solution during cell fabrication.

[0104] (Example 13, Comparative Example 5) Using an HS cell (manufactured by Takizawa Co., Ltd.), metallic Li, a polyethylene porous film (manufactured by Toray Industries, Inc., thickness 5 μm, air permeability 160 seconds / 100 cc) previously immersed in 1 M LiTFSI EC / DEC = 1 / 1 (volume ratio) for 24 hours, the polymer film described in Table 3, a polyethylene porous film (manufactured by Toray Industries, Inc., thickness 5 μm, air permeability 110 seconds / 100 cc) previously immersed in 1 M LiTFSI EC / DEC = 1 / 1 (volume ratio) for 24 hours, and metallic Li were laminated and sealed. For the fabricated cell, after performing a preliminary operation test with a current density of 0.1 mA / cm 2 for 1 hour each for charge and discharge and for 3 cycles, a cycle test was performed at a current density of 0.5 mA / cm 2 for 1 hour each for charge and discharge. The number of cycles at the point when the applied voltage became 250 mV or more and 20 mV or less was recorded. The weight ratio of the electrolytic solution to the film was calculated by measuring the weight of the polymer film and the amount of the electrolytic solution during cell fabrication. The weight of the electrolytic solution at this time is the weight difference of the polyethylene porous film before and after electrolytic solution immersion.

[0105] (Example 14) The polymer solution P4 was cast onto glass as a support and dried by vacuum drying at 90 °C, 200 Pa for 20 minutes until it became self-supporting. Next, metallic Li was placed on the polymer film under an Ar atmosphere, and after removing it from the glass, vacuum drying was performed at 90 °C, 200 Pa for 5 hours to obtain an electrode composite.

[0106] Using an HS cell (manufactured by Takizawa Co., Ltd.), an electrode composite prepared under an argon atmosphere (oxygen concentration of 0.1 ppm or less, dew point of -75 °C or less), a polyethylene porous membrane (manufactured by Toray Industries, Inc., thickness 5 μm, air permeability 110 seconds / 100 cc), and the electrode composite were laminated, and 300 μL of 1 M LiTFSI EC / DEC = 1 / 1 (volume ratio) was injected and sealed. At that time, the polymer film of the electrode composite was laminated so as to be in contact with the polyethylene porous membrane. For the fabricated cell, after performing a preliminary operation test with a current density of 0.1 mA / cm 2 , charge and discharge for 1 hour each, and 3 cycles, a cycle test was performed at each current density and charge-discharge time described in Table 3, and the number of cycles at the point when the applied voltage became 250 mV or more and 20 mV or less was recorded.

[0107] Compared with the comparative example, the polymer film containing the polymer of the example is excellent in ionic conductivity or liquid separation property. For the microporous membranes widely used in conventional lithium-ion batteries, the cation transport rate and liquid separation property are extremely high. These polymer films of the examples are effective for batteries requiring ionic conductivity and liquid separation property, particularly lithium-air batteries. Since Example 11 has a high number of cycles and Example 12 has a high current density compared with Comparative Example 4, it can be seen that they are excellent in battery life and capacity, respectively.

[0108]

Table 1

[0109]

Table 2

[0110]

Table 3

Claims

1. A polymer in which the atomic number density of atoms having a charge density of -1.0 or more and -0.5 or less is 0% or more and 7% or less, and the atomic number density of atoms having a charge density of 0.25 or more and 1.0 or less is 5% or more and 100% or less.

2. The polymer according to claim 1, wherein the glass transition temperature of the polymer is 51°C or more and 400°C or less.

3. The polymer according to claim 1, wherein the atomic number density of atoms having a charge density of -0.5 or more and less than 0 is 9% or more and 100% or less.

4. The polymer according to claim 1, wherein the atomic number density of hydrogen atoms having a charge density of 0.25 or more and 1 or less is 5% or more and 100% or less.

5. A film containing the polymer according to claim 1.

6. The film according to claim 5, which has a non-porous region.

7. The film according to claim 5 or 6, wherein the cation concentration is 1 μmol / g or more and 50000 μmol / g or less.

8. The film according to claim 5 or 6, wherein the lithium ion concentration is 1 μmol / g or more and 50000 μmol / g or less.

9. The ionic conductivity is 1.0×10 －７ The film according to claim 5 or 6, wherein the ionic conductivity is 1.0×10 S / cm or more and 1.0×10 S / cm or less.

10. The film according to claim 5 or 6, wherein the cation transport rate is 0.5 or more and 1.0 or less.

11. The film according to claim 5 or 6, wherein the haze is 0% or more and 30% or less.

12. The film according to claim 5 or 6, containing at least one of bis(trifluoromethanesulfonamide) ion, bis(fluorosulfonamide) ion, trifluoromethanesulfonic acid ion, PF ６ ion, ClO ４ ion, BF ４ ion.

13. The film according to claim 5 or 6, wherein the lithium salt weight concentration is 0% by weight or more and 80% by mass or less.

14. The association constant with the polymer is 1.0 M －１ or more and 1.0 × 10 １０ M －１ The film according to claim 5 or 6, comprising an anion that is below.

15. A solution containing the polymer according to claim 1.

16. An electrode composite having the film according to claim 5 or 6 and an electrode in proximity.

17. A battery containing the polymer according to claim 1 or the film according to claim 5.

18. The battery according to claim 17, wherein the weight ratio of the electrolyte to the film is 0 or more and 5 or less.

19. A vehicle, unmanned transporter, electronic device, unmanned aerial vehicle, or stationary power source containing the battery according to claim 17.

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