Composite material, separator, battery, and power consuming device

Abstract

This application relates to a composite material, a separator, a battery, and an electrical device. The separator includes a substrate and a functional layer disposed on at least one side of the substrate. The functional layer includes a composite material comprising a metal-organic framework compound and a chelate interconnected with each other. The metal-organic framework compound is formed by coordination of a metal ion and an organic ligand. The valence of the metal ion is greater than or equal to divalent, and the organic ligand comprises a polycarboxylic acid group.

Description

Technical Field

[0001] This application relates to a composite material, a separator, a battery, and an electrical device. Background Technology

[0002] Batteries, with their high capacity and long lifespan, are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools. Due to significant advancements in battery technology, higher performance requirements have been placed on them. To improve the performance of individual battery cells, the separator within the battery is typically optimized and improved.

[0003] However, when separators are currently used in batteries, the reliability and cycle performance of the batteries are still relatively poor. Summary of the Invention

[0004] This application provides a composite material, a separator, a battery, and an electrical device. The battery described in this application can improve both its reliability and cycle performance.

[0005] In a first aspect, embodiments of this application propose an isolation membrane, the isolation membrane comprising a substrate and a functional layer disposed on at least one side of the substrate, the functional layer comprising a composite material, the composite material comprising a metal-organic framework compound and a chelate connected to each other, the metal-organic framework compound being formed by coordination of a metal ion and an organic ligand, the metal ion having a valence greater than or equal to divalent, and the organic ligand comprising a polycarboxylic acid group.

[0006] Therefore, in this embodiment, the separator includes a composite material comprising a metal-organic framework compound and a chelate interconnected with each other. The metal-organic framework compound is formed by coordination of metal ions and organic ligands, wherein the metal ions have a valence of divalent or higher, and the organic ligands include polycarboxylic acid structures. When the separator is applied to a battery cell, the metal-organic framework material can bind metal impurity ions through pore size and electrostatic synergy, and the chelate can further bind to the metal impurity ions through chelation, reducing the content of metal impurity ions in the electrolyte, thereby reducing the number of metal impurity ions migrating to the negative electrode, increasing the number of active ion insertion sites in the negative electrode, and improving the reversible capacity of the battery cell; it also mitigates the risk of metal impurity ions precipitating on the surface of the negative electrode and forming metal dendrites, improving the reliability of the battery cell; and it can also reduce the self-discharge rate of the battery cell, improving the cycle performance of the battery cell.

[0007] In some embodiments, the valence of the metal ion is greater than or equal to tetravalent; optionally, the valence of the metal ion is greater than or equal to pentavalent; further optionally, the valence of the metal ion is greater than or equal to hexavalent. As the valence of the metal ion increases, the number of bonding sites that the metal ion can provide increases, that is, the number of organic ligands coordinated to the metal ion increases. This is beneficial for forming metal-organic framework compounds with smaller pore sizes, and facilitates the adsorption of metal impurity ions by the metal-organic framework compounds through pore size interaction.

[0008] In some embodiments, the metal ions may include Zr. 2+ Zr 3+ Zr 4+ Bi 3+ Bi 5+ Zn 2+ Hf 4+ Co 2+ Co 3+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; optionally, the metal ion may include Zr 3+ Zr 4+ Bi 3+ Bi 5+ Hf 4+ Co 3+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; further optionally, the metal ion may include Zr 4+ Bi 5+ Hf 4+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; more preferably, the metal ion may include Bi. 5+ Mn 5+ and Mn 6+ At least one of the following; more preferably, the metal ion may include Mn 6+ .

[0009] In some embodiments, the organic ligand includes at least one selected from phthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, 4,4'-sulfonyl dibenzoic acid, and 4,4'-dicarboxylic acid diphenyl ether. These materials are stable in organic solvents for extended periods, and because they all possess a polycarboxylic acid structure, they are conducive to binding with chelates, thereby improving the structural stability of the composite material.

[0010] In some embodiments, the chelate comprises at least one of a carboxylic acid group, a phosphonic acid group, and octanoyl hydroxamic acid; optionally, the chelate containing the carboxylic acid group comprises at least one of ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, and diethylenetriaminepentaacetic acid; optionally, the chelate containing the phosphonic acid group comprises one or more of hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, triethylenetetraminehexamethylenephosphonic acid, bis(1,6-hexylene)triaminepentamethylenephosphonic acid, and polyaminopolyethertetramethylenephosphonic acid. The above-mentioned chelates exhibit stronger coordination with metal impurity ions, which is beneficial for stabilizing metal impurity ions in the separator membrane. Furthermore, the above-mentioned chelates have good compatibility with organic solvents in the electrolyte, which can improve the wetting performance of the separator membrane by the electrolyte.

[0011] In some embodiments, the volume average particle size Dv50 of the composite material is from 100 nm to 300 nm; and / or the average pore size of the composite material is from 0.50 nm to 1.10 nm. When the average pore size of the composite material is within the above range, the average pore size of the composite material is relatively small, which is beneficial for the composite material to exert the effect of pore size and adsorb metal impurity ions into the pore structure of the composite material.

[0012] In some embodiments, based on the mass percentage of the composite material, the ratio of the mass percentage of the chelate to the mass percentage of the metal-organic framework compound is 0.01 to 0.10:1. When the mass percentage ratio of the chelate to the metal-organic framework compound is within the above range, the metal-organic framework compound plays a major role in adsorbing metal impurity ions, while the chelate plays an auxiliary role in chelating metal impurity ions. Together, they stabilize the metal impurity ions in the composite material, effectively reducing the content of metal impurity ions in the system.

[0013] In some embodiments, based on the mass of the functional layer, the mass percentage of the composite material is 0.1% to 1.0%. When the mass percentage of the composite material is within the above range, it can effectively adsorb and stabilize metal impurity ions in the battery cell system.

[0014] In some embodiments, the functional layer further includes heat-resistant particles; optionally, the heat-resistant particles account for less than or equal to 50% of the mass percentage of the functional layer, and the heat-resistant particles can improve the heat resistance of the separator.

[0015] In some embodiments, the thickness of the functional layer is from 0.1 μm to 4 μm, optionally from 0.5 μm to 3 μm; and / or the coating basis weight of the functional layer is 1 g / m². 2 Up to 3g / m 2When the thickness of the functional layer is within the above-mentioned range, the overall mechanical properties of the separator can be improved. When the coating weight of the functional layer is within the above-mentioned range, the overall mechanical properties of the separator can be improved.

[0016] In some embodiments, the thickness of the substrate is less than or equal to 16 μm, and can be selected from 5 μm to 14 μm. The functional layer of the embodiments of this application is beneficial to improving the overall mechanical properties of the separator, thereby allowing the use of a thinner substrate, which helps to improve the energy density of the battery cell.

[0017] Secondly, embodiments of this application also propose a composite material comprising a metal-organic framework compound and a chelate connected to each other, wherein the metal-organic framework compound is formed by coordination of a metal ion and an organic ligand, wherein the valence of the metal ion is greater than or equal to divalent, and the organic ligand comprises a polycarboxylic acid group.

[0018] In some embodiments, the valence of the metal ion is greater than or equal to tetravalent; optionally, the valence of the metal ion is greater than or equal to pentavalent; further optionally, the valence of the metal ion is greater than or equal to hexavalent. As the valence of the metal ion increases, the number of bonding sites that the metal ion can provide increases, that is, the number of organic ligands coordinated to the metal ion increases. This is beneficial for forming metal-organic framework compounds with smaller pore sizes, and facilitates the adsorption of metal impurity ions by the metal-organic framework compounds through pore size interaction.

[0019] In some embodiments, the metal ions may include Zr. 2+ Zr 3+ Zr 4+ Bi 3+ Bi 5+ Zn 2+ Hf 4+ Co 2+ Co 3+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; optionally, the metal ion may include Zr 3+ Zr 4+ Bi 3+ Bi 5+ Hf 4+ Co 3+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; further optionally, the metal ion may include Zr 4+ Bi 5+ Hf 4+ Mn 4+ Mn5+ and Mn 6+ At least one of the following; more preferably, the metal ion may include Bi. 5+ Mn 5+ and Mn 6+ At least one of the following; more preferably, the metal ion may include Mn 6+ .

[0020] In some embodiments, the organic ligand includes at least one selected from phthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, 4,4'-sulfonyl dibenzoic acid, and 4,4'-dicarboxylic acid diphenyl ether. These materials are stable in organic solvents for extended periods, and because they all possess a polycarboxylic acid structure, they are conducive to binding with chelates, thereby improving the structural stability of the composite material.

[0021] In some embodiments, the chelate comprises at least one of a carboxylic acid group, a phosphonic acid group, and octanoyl hydroxamic acid; optionally, the chelate containing the carboxylic acid group comprises at least one of ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, and diethylenetriaminepentaacetic acid; optionally, the chelate containing the phosphonic acid group comprises one or more of hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, triethylenetetraminehexamethylenephosphonic acid, bis(1,6-hexylene)triaminepentamethylenephosphonic acid, and polyaminopolyethertetramethylenephosphonic acid. The above-mentioned chelates exhibit stronger coordination with metal impurity ions, which is beneficial for stabilizing metal impurity ions in the separator membrane. Furthermore, the above-mentioned chelates have good compatibility with organic solvents in the electrolyte, which can improve the wetting performance of the separator membrane by the electrolyte.

[0022] In some embodiments, the volume average particle size Dv50 of the composite material is from 100 nm to 300 nm; and / or the average pore size of the composite material is from 0.50 nm to 1.10 nm. When the average pore size of the composite material is within the above range, the average pore size of the composite material is relatively small, which is beneficial for the composite material to exert the effect of pore size and adsorb metal impurity ions into the pore structure of the composite material.

[0023] In some embodiments, based on the mass percentage of the composite material, the ratio of the mass percentage of the chelate to the mass percentage of the metal-organic framework compound is 0.01 to 0.10:1. When the mass percentage ratio of the chelate to the metal-organic framework compound is within the above range, the metal-organic framework compound plays a major role in adsorbing metal impurity ions, while the chelate plays an auxiliary role in chelating metal impurity ions. Together, they stabilize the metal impurity ions in the composite material, effectively reducing the content of metal impurity ions in the system.

[0024] Thirdly, embodiments of this application also provide a battery, the battery including a separator, the separator being the separator as described in any embodiment of the first aspect of this application, or the separator including a substrate and a functional layer disposed on at least one side of the substrate, the functional layer including a composite material as described in any embodiment of the second aspect of this application.

[0025] Fourthly, embodiments of this application also provide an electrical device comprising a battery as described in any embodiment of the third aspect of this application. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of one embodiment of the battery cell of this application.

[0028] Figure 2 yes Figure 1 An exploded view of the implementation method of the battery cell.

[0029] Figure 3 This is a schematic diagram of one embodiment of the battery module of this application.

[0030] Figure 4 This is a schematic diagram of one embodiment of the battery pack of this application.

[0031] Figure 5 yes Figure 4 An exploded view of an embodiment of the battery pack shown.

[0032] Figure 6 This is a schematic diagram of one embodiment of an electrical device that uses the battery cell of this application as a power source.

[0033] The accompanying drawings may not be drawn to scale.

[0034] The annotations in the attached figures are explained as follows:

[0035] 1. Battery pack; 2. Upper casing; 3. Lower casing; 4. Battery module;

[0036] 5. Battery cell; 51. Housing; 52. Electrode assembly;

[0037] 53. Cover plate;

[0038] 6. Electrical appliances. Detailed Implementation

[0039] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the separator, battery cell, battery, and power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0040] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0041] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0042] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0043] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0044] A battery cell includes a positive electrode, a negative electrode, a separator, and an electrolyte. The separator is located between the positive and negative electrodes to separate them. The positive electrode includes a positive active material, which is the donor of active ions such as sodium ions and lithium ions. The negative electrode is the acceptor of active ions. The electrolyte provides a migration path for active ions between the positive and negative electrodes. During the battery cell manufacturing process, metal impurity ions are inevitably introduced into the positive active material and / or electrolyte, which may include at least one of the following: iron ions, copper ions, zinc ions, cadmium ions, chromium ions, manganese ions, cobalt ions, and nickel ions. These metal ions typically do not include active ions such as lithium ions, sodium ions, and potassium ions. During the charging process of a battery cell, metal impurity ions in the positive electrode active material can dissolve in the electrolyte, increasing the content of metal impurity ions in the electrolyte. These metal impurity ions have a lower reduction potential than active ions, and they can preferentially embed into the negative electrode, reducing the number of active ion embedding sites and lowering the reversible capacity of the battery cell. Furthermore, metal impurity ions may precipitate on the surface of the negative electrode, forming metal dendrites. The growth of these dendrites may puncture the separator of the battery cell, causing direct contact between the positive and negative electrodes and triggering a short circuit. This reduces the reliability of the battery cell, increases the self-discharge rate of the battery cell, and deteriorates its cycle performance.

[0045] In view of the above problems, this application proposes a separator membrane comprising a composite material, which includes a metal-organic framework compound and a chelate interconnected with each other. The metal-organic framework compound is formed by coordination of metal ions and organic ligands, wherein the metal ions have a valence of divalent or higher, and the organic ligands include polycarboxylic acid structures. When the separator membrane is applied to a battery cell, the metal-organic framework material can bind metal impurity ions through pore size and electrostatic synergy, and the chelate can further bind to the metal impurity ions through chelation, reducing the content of metal impurity ions in the electrolyte, thereby reducing the number of metal impurity ions migrating to the negative electrode, increasing the number of sites for active ion insertion in the negative electrode, and improving the reversible capacity of the battery cell; it also mitigates the risk of metal impurity ions precipitating on the surface of the negative electrode and forming metal dendrites, improving the reliability of the battery cell; and it can also reduce the self-discharge rate of the battery cell, improving the cycle performance of the battery cell.

[0046] Separating membrane

[0047] In a first aspect, embodiments of this application propose an isolation membrane, the isolation membrane comprising a substrate and a functional layer disposed on at least one side of the substrate, the functional layer comprising a composite material, the composite material comprising a metal-organic framework compound and a chelate connected to each other, the metal-organic framework compound being formed by coordination of a metal ion and an organic ligand, the metal ion having a valence of divalent or higher, and the organic ligand comprising a polycarboxylic acid group.

[0048] The substrate includes two surfaces that are opposite each other along the thickness direction of the separator film. The functional layer can be disposed on either of the two surfaces or on both surfaces.

[0049] The separator includes a substrate and a functional layer. The functional layer is disposed on one of the two surfaces of the substrate. In this case, when the separator is applied to a battery cell, the substrate of the separator can be disposed closer to the positive electrode plate relative to the functional layer, that is, the functional layer is located on the side of the substrate away from the positive electrode plate; or the functional layer of the separator can be disposed closer to the positive electrode plate relative to the substrate, that is, the substrate is located on the side of the functional layer away from the positive electrode plate.

[0050] Metal-organic frameworks (MOFs) are porous materials formed by the self-assembly of metal ions and organic ligands through coordination bonds. The organic ligands include polycarboxylic acid groups, which can serve as organic frameworks to connect metal ions. This allows polycarboxylic acids and metal ions to alternately connect and form a three-dimensional network structure, making the coordination between organic ligands and metal ions more stable. The resulting MOF compounds have a more stable framework structure, and the pore size of the three-dimensional network structure is small, such as at the nanometer scale. This allows it to serve as a channel for adsorbing metal impurity ions. Furthermore, the electrostatic interaction of the organic framework in the three-dimensional network structure can further adsorb metal impurity ions. The electrostatic interaction has a stronger selectivity for high-valence metal impurity ions and a relatively smaller effect on the adsorption of low-valence active ions such as lithium ions and sodium ions.

[0051] Metal ions, as the skeletal center of metal-organic frameworks (MOFs), can provide active linkage sites. Metal ions have relatively high valence states, such as divalent or higher, and can provide a relatively large number of linkage sites, meaning that there are more organic ligands that can be attached to the metal ions. This is conducive to forming MOFs with smaller pore sizes. These pore sizes allow metal impurity ions to enter the porous structure of the MOF, enabling the MOF to adsorb metal impurity ions through pore size effects and electrostatic synergistic effects, thereby reducing the number of metal impurity ions migrating to the negative electrode.

[0052] Because metal-organic frameworks (MOFs) have limited adsorption capacity for metal impurity ions, there is a risk of desorption once the adsorption capacity reaches saturation. However, the embodiments of this application incorporate chelates into the framework structure of the MOF, which facilitates further chelation of metal impurity ions. Specifically, the polycarboxylic acid groups possess active linkage sites, which facilitate coordination with the chelates, thus incorporating the chelates into the framework structure of the MOF. Since the metal ions have relatively high valence states and may also possess active sites, the chelates can coordinate with the metal ions through these active sites, resulting in higher stability of the connection between the chelates and the MOF framework structure, and ultimately, higher structural stability of the resulting composite material. Chelates can combine with metal impurity ions through coordination to form chelates, stabilizing the metal impurity ions within the chelate. This further reduces the risk of metal impurity ions migrating to the negative electrode and mitigating the risk of metal impurity ions precipitating on the surface of the negative electrode and forming metal dendrites, thereby improving the reliability of the battery cell. It can also reduce the self-discharge rate of the battery cell and improve its cycle performance.

[0053] The valence of metal ions can be divalent, trivalent, tetravalent, pentavalent, hexavalent, heptavalent, or any combination of two of these valences. As the valence of a metal ion increases, the number of bonding sites it can provide increases, meaning the number of organic ligands that can be coordinated to the metal ion increases. This is beneficial for forming metal-organic frameworks (MOFs) with smaller pore sizes, which in turn facilitates the adsorption of metal impurity ions by these MOFs through pore size.

[0054] In some embodiments, the valence of the metal ion is greater than or equal to trivalent; alternatively, the valence of the metal ion is greater than or equal to tetravalent; alternatively, the valence of the metal ion is greater than or equal to pentavalent; further alternatively, the valence of the metal ion is greater than or equal to hexavalent. When the valence of the metal ion is within the above range, it can provide more active linkage sites, which is beneficial for coordination and binding with organic ligands and for binding with chelates, resulting in a more stable structure of the composite material.

[0055] In some embodiments, the metal ions may include Zr. 2+ Zr 3+ Zr 4+ Bi 3+ Bi 5+ Zn 2+ Hf 4+ Co 2+ Co 3+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; optionally, the metal ion may include Zr 3+ Zr 4+ Bi 3+ Bi 5+ Hf 4+ Co 3+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; further optionally, the metal ion may include Zr 4+ Bi 5+ Hf 4+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; more preferably, the metal ion may include Bi. 5+ Mn 5+ and Mn 6+ At least one of the following; more preferably, the metal ion may include Mn 6+ .

[0056] In some embodiments, the polycarboxylic acid group may include at least one of dicarboxylic acid groups, tricarboxylic acid groups, and tetracarboxylic acid groups. Polycarboxylic acids can serve as an organic framework for linking metal ions, alternating with metal ions to form a three-dimensional network structure, which is beneficial for forming a three-dimensional network structure with nanoscale pores. However, as the number of carboxylic acids increases, the pore size becomes too small, which is not conducive to the adsorption of metal impurity ions. Therefore, optionally, the polycarboxylic acid group may include a dicarboxylic acid group. Dicarboxylic acids are more conducive to forming a symmetrical structure, improving the stability of the three-dimensional network structure.

[0057] For example, the organic ligand may include at least one of phthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, 4,4'-sulfonyl dibenzoic acid, and 4,4'-dicarboxylic acid diphenyl ether. The above materials are stable in organic solvents for extended periods, and because they all possess polycarboxylic acid structures, they are conducive to binding with chelates, thus improving the structural stability of the composite material. Furthermore, the inclusion of dicarboxylic acid structures in the above organic ligands facilitates the adsorption of metal impurity ions through pore size interactions and electrostatic interactions.

[0058] For example, the organic coordination may include 5-nitro-1,2,3-benzenetricarboxylic acid, 4,4'4"-triphenylamine tricarboxylic acid.

[0059] In some embodiments, the chelator may include at least one of a carboxylic acid group, a phosphonic acid group, and an octanoyl hydroxamic acid. The chelator exhibits stronger coordination with the metal impurity ions, which is beneficial for stabilizing the metal impurity ions within the separator membrane. Furthermore, the chelator demonstrates good compatibility with organic solvents in the electrolyte, thereby improving the wettability of the separator membrane by the electrolyte.

[0060] Optionally, the chelate containing a carboxylic acid group may include at least one of ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, and diethylenetriaminepentaacetic acid.

[0061] Optionally, the chelate containing the phosphonic acid group may include one or more of the following: hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, triethylenetetraminehexamethylenephosphonic acid, bis(1,6-hexylene)triaminepentamethylenephosphonic acid, and polyaminopolyethertetramethylenephosphonic acid.

[0062] Metal-organic frameworks are nanomaterials with relatively small particle sizes. The composite materials formed by combining metal-organic frameworks and chelates are also nanomaterials with relatively small particle sizes. When composite materials are placed in functional layers, the thickness of the functional layers can be made relatively small.

[0063] In some embodiments, the volume average particle size Dv50 of the composite material can be from 100 nm to 300 nm. For example, the volume average particle size Dv50 of the composite material can be 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, or a range consisting of any two of the above values.

[0064] In the embodiments of this application, the volume average particle size Dv50 of the material has a well-known meaning in the art. The volume average particle size Dv50 of the material refers to the particle size corresponding to 50% of the volume distribution. It can be detected using equipment and methods known in the art. A certain amount of composite material is taken as a sample, and the volume average particle size Dv50 is tested using a Mastersizer2000E laser particle size analyzer according to the test standard GB / T 19077-2016.

[0065] In some embodiments, the average pore size of the composite material can be from 0.50 nm to 1.10 nm. When the average pore size of the composite material is within the above range, the average pore size of the composite material is relatively small, which is beneficial for the composite material to exert the effect of pore size and adsorb metal impurity ions into the pore structure of the composite material.

[0066] For example, the average pore size of the composite material can be 0.5 nm, 0.55 nm, 0.60 nm, 0.65 nm, 0.70 nm, 0.75 nm, 0.80 nm, 0.85 nm, 0.90 nm, 0.95 nm, 1.00 nm, 1.05 nm, 1.10 nm, or a range of any two of the above values.

[0067] In the embodiments of this application, the average pore size of the composite material has a meaning known in the art and can be detected using equipment and methods known in the art. A certain amount of composite material is taken as a sample, and the average pore size is tested according to the test standard GB / T 19587-2017 using a Tri-Star 3020 surface area pore size analyzer from Micromeritics, USA.

[0068] In some embodiments, based on the mass percentage of the composite material, the ratio of the mass percentage of the chelate to the mass percentage of the metal-organic framework compound is 0.01 to 0.10:1. When the mass percentage ratio of the chelate to the metal-organic framework compound is within the above range, the metal-organic framework compound plays the main role in adsorbing metal impurity ions, while the chelate plays an auxiliary role in chelating metal impurity ions. Together, they stabilize the metal impurity ions in the composite material, effectively reducing the content of metal impurity ions in the system.

[0069] For example, the ratio of the mass percentage of the chelate to the mass percentage of the metal-organic framework compound can be 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.10:1, or a range of any two of the above values.

[0070] In some embodiments, based on the mass of the functional layer, the mass percentage of the composite material is 0.1% to 1.0%; when the mass percentage of the composite material is within the above range, it can effectively adsorb and stabilize the metal impurity ions in the battery cell system.

[0071] For example, the mass percentage of the composite material can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, or a range of any two of the above values.

[0072] In some implementations, the functional layer may also include heat-resistant particles, which may include inorganic particles.

[0073] In some embodiments, the inorganic particles constitute less than or equal to 50% of the functional layer by mass, which can improve the heat resistance of the separator. Exemplarily, the mass percentage of inorganic particles in the functional layer is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any range of two of the above values.

[0074] Inorganic particles may include at least one of the following: inorganic particles having a dielectric constant of 5 or higher, inorganic particles having the ability to transport active ions, and inorganic particles capable of undergoing electrochemical oxidation and reduction.

[0075] In some embodiments, inorganic particles having a dielectric constant of 5 or higher may include boehmite (γ-AlOOH), aluminum oxide (Al2O3), barium sulfate (BaSO4), magnesium oxide (MgO), magnesium hydroxide (Mg(OH)2), silicon oxide SiOx (0<x≤2), tin dioxide (SnO2), titanium oxide (TiO2), calcium oxide (CaO), zinc oxide (ZnO), zirconium oxide (ZrO2), yttrium oxide (Y2O3), nickel oxide (NiO), hafnium dioxide (HfO2), cerium oxide (CeO2), zirconium titanate (ZrTiO3), barium titanate (BaTiO3), magnesium fluoride (MgF2), Pb(Zr,Ti)O3 (abbreviated as PZT), and Pb 1-m La m Zr 1-n Ti n O3 (abbreviated as PLZT, 0 < m < 1, 0 < n < 1) and Pb (Mg3Nb) 2 / 3 At least one of O3-PbTiO3 (abbreviated as PMN-PT).

[0076] In some embodiments, the inorganic particles capable of transporting active ions may include lithium phosphate (Li3PO4) and lithium titanium phosphate (Li... x Ti y (PO4)3, 0 < x < 2, 0 < y < 3), lithium titanium aluminum phosphate (Li x Al y Ti z (PO4)3, 0 < x < 2, 0 < y < 1, 0 < z < 3), (LiAlTiP)xOy type glass (0 < x < 4, 0 < y < 13), lithium lanthanum titanate (Li x La y TiO3, 0 < x < 2, 0 < y < 3), lithium germanium thiophosphate (Li x Ge y P z S w , 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), lithium nitride (LixNy, 0 < x < 4, 0 < y < 2), SiS2 type glass (Li x Si y S z (0 < x < 3, 0 < y < 2, 0 < z < 4) and P2S5 type glass (Li x P y S z At least one of the following: 0 < x < 3, 0 < y < 3, 0 < z < 7.

[0077] In some embodiments, the inorganic particles capable of undergoing electrochemical oxidation and reduction may include at least one of lithium-containing transition metal oxides, lithium-containing phosphates with an olivine structure, carbon-based materials, silicon-based materials, tin-based materials, and lithium-titanium compounds.

[0078] In some embodiments, the functional layer may further include an adhesive. As an example, the adhesive may include at least one of aqueous acrylic resins (e.g., homopolymers of acrylic acid, methacrylic acid, sodium acrylate monomers, or copolymers with other comonomers), polyvinyl alcohol (PVA), isobutylene-maleic anhydride copolymers, and polyacrylamide.

[0079] In some embodiments, the thickness of the functional layer can be from 0.1 μm to 4 μm, optionally from 0.5 μm to 3 μm. A thickness within this range improves the overall mechanical properties of the separator. In this application, the thickness of the functional layer refers to the thickness of the functional layer located on one side of the substrate. Exemplarily, the thickness of the functional layer can be 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, or a range consisting of any two of these values.

[0080] In some embodiments, the basis weight of the functional layer is 1 g / m². 2 Up to 3g / m 2 The coating weight of the functional layer refers to the coating weight of the functional layer located on one side of the substrate. When the coating weight of the functional layer is within the above range, it can improve the overall mechanical properties of the release liner.

[0081] In some embodiments, the thickness of the substrate may be less than or equal to 16 μm, and may be selected from 5 μm to 14 μm. The functional layer of the embodiments of this application is beneficial to improving the overall mechanical properties of the separator, thereby allowing for the use of a thinner substrate, which helps to improve the energy density of the battery cell. Exemplarily, the thickness of the substrate may be 1 μm, 2 μm, 3 μm, 5 μm, 10 μm, 12 μm, 15 μm, 16 μm, or any combination of two of the above values.

[0082] In some embodiments, the porosity of the substrate is greater than or equal to 25%. When the porosity of the substrate is within the above range, the air permeability of the substrate can be ensured to facilitate the migration of active ions, and due to the relatively small porosity, the mechanical properties of the substrate can also be guaranteed, providing good support for the functional layer.

[0083] In some embodiments, the substrate may include at least one of a polyolefin-based polymer (e.g., polyethylene, polypropylene, polyvinylidene fluoride), porous glass fiber, and porous nonwoven fabric. The substrate may be a single-layer film or a multilayer composite film. When the substrate is a multilayer composite film, the materials of each layer may be the same or different. The substrate formed from the above polymers exhibits good chemical and mechanical stability.

[0084] It should be noted that the functional layer parameters and functional layer parameters (such as thickness) of the aforementioned separator are all functional layer parameters on one side of the substrate. When the functional layer parameters are disposed on both sides of the substrate, if the functional layer parameters on either side meet the requirements of this application, it is considered to fall within the protection scope of this application.

[0085] Methods for preparing isolation membranes

[0086] Secondly, embodiments of this application provide a method for preparing a separating membrane, the method comprising:

[0087] Step S100: Provide a metal-organic framework compound, which is formed by coordination of a metal ion and an organic ligand, wherein the valence of the metal ion is greater than or equal to divalent, and the organic ligand includes a polycarboxylic acid group;

[0088] Step S200: The chelate is provided to the metal-organic framework compound to prepare the composite material;

[0089] In step S300, the composite material is provided onto at least one surface of the base film to form a functional layer.

[0090] According to the method of the embodiments of this application, the isolation membrane can be easily prepared.

[0091] In some embodiments, step S300 may include dispersing the composite material in a heat-resistant slurry and coating the heat-resistant slurry onto at least one surface of the base film to form a functional layer.

[0092] Composite materials

[0093] Thirdly, embodiments of this application propose a composite material comprising a metal-organic framework compound and a chelate connected to each other, wherein the metal-organic framework compound is formed by coordination of a metal ion and an organic ligand, wherein the metal ion has a valence of divalent or higher, and the organic ligand comprises a polycarboxylic acid group.

[0094] In some embodiments, the valence of the metal ion is greater than or equal to trivalent; optionally, the valence of the metal ion is greater than or equal to tetravalent; optionally, the valence of the metal ion is greater than or equal to pentavalent; further optionally, the valence of the metal ion is greater than or equal to hexavalent.

[0095] In some embodiments, the metal ions may include Zr. 2+ Zr 3+ Zr 4+ Bi 3+ Bi 5+ Zn 2+ Hf 4+ Co 2+ Co 3+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; optionally, the metal ion may include Zr 3+ Zr 4+ Bi 3+ Bi 5+ Hf 4+ Co 3+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; further optionally, the metal ion may include Zr 4+ Bi 5+ Hf 4+ Mn 4+ Mn 5+ and Mn 6+ At least one of the following; more preferably, the metal ion may include Bi. 5+ Mn 5+ and Mn 6+ At least one of the following; more preferably, the metal ion may include Mn 6+ .

[0096] In some embodiments, the polycarboxylic acid group may include at least one of a dicarboxylic acid group, a tricarboxylic acid group, and a tetracarboxylic acid group; optionally, the polycarboxylic acid group may include a dicarboxylic acid group.

[0097] For example, the organic ligand may include at least one of phthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, 4,4'-sulfonyl dibenzoic acid, and 4,4'-dicarboxylic acid diphenyl ether. The above materials are stable in organic solvents for extended periods, and because they all possess a polycarboxylic acid structure, they are conducive to binding with chelates, thereby improving the structural stability of the composite material.

[0098] For example, the organic coordination may include 5-nitro-1,2,3-benzenetricarboxylic acid, 4,4'4"-triphenylamine tricarboxylic acid.

[0099] In some embodiments, the chelate may include at least one of a carboxylic acid group, a phosphonic acid group, and an octanoyl hydroxamic acid.

[0100] Optionally, the chelate containing a carboxylic acid group may include at least one of ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, and diethylenetriaminepentaacetic acid.

[0101] Optionally, the chelate containing the phosphonic acid group may include one or more of the following: hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, triethylenetetraminehexamethylenephosphonic acid, bis(1,6-hexylene)triaminepentamethylenephosphonic acid, and polyaminopolyethertetramethylenephosphonic acid.

[0102] In some embodiments, the volume average particle size Dv50 of the composite material can be from 100 nm to 300 nm.

[0103] In some embodiments, the average pore size of the composite material can be from 0.50 nm to 1.10 nm.

[0104] In some embodiments, based on the mass of the composite material, the ratio of the mass percentage of the chelate to the mass percentage of the metal-organic framework compound is 0.01 to 0.10:1.

[0105] battery cell

[0106] Fourthly, embodiments of this application provide a battery cell including a separator. The separator may include the separator of any embodiment of the first aspect of this application or a separator prepared by the method of any embodiment of the second aspect of this application. The separator serves to isolate the positive electrode and the negative electrode. By employing the above-mentioned separator, the reliability, self-discharge performance, and cycle performance of the battery cell can be improved.

[0107] [Positive electrode plate]

[0108] In some implementations, the battery cell also includes a positive electrode.

[0109] The positive electrode sheet includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector, the positive active material layer including a positive active material.

[0110] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0111] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0112] In some embodiments, the positive electrode active material may be a positive electrode active material known in the art for use in battery cells. As an example, the positive electrode active material may include at least one of the following materials: layered positive electrode active materials (e.g., ternary, lithium nickel oxide / sodium, lithium cobalt oxide / sodium, lithium manganese oxide / sodium, lithium-rich / sodium layered and rock salt phase layered materials, etc.), olivine-type phosphate active materials, spinel-structured positive electrode active materials (e.g., spinel lithium manganese oxide, spinel lithium nickel manganese oxide, lithium-rich spinel lithium manganese oxide, and lithium nickel manganese oxide, etc.).

[0113] For example, the general formula of the layered structure positive electrode active material is Li x A y Ni a Co b Mn c M (1-a-b-c) Y z Wherein, 0≤x≤2.1, 0≤y≤2.1, and 0.9≤x+y≤2.1; 0≤a≤1, 0≤b≤1, 0≤c≤1, and 0.1≤a+b+c≤1; 1.8≤z≤3.5; A includes one or more of Na, K, and Mg; M includes one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; Y includes one or more of O and F. Specifically, layered positive electrode active materials may include lithium cobalt oxide (LCO), lithium nickel oxide (LNO), and lithium manganese oxide (LMO), etc.

[0114] Optionally, the layered structure positive electrode active material is a ternary material, such as 0 < a ≤ 1, 0 < b ≤ 1, 0 < c ≤ 1. For example, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811) and LiNi 0.5 Co0.2 Mn 0.3 One or more of O2 (NCM523).

[0115] For example, the general formula of olivine-type phosphate active substances is Li x A y Me a M b P 1-c X c Y z Wherein, 0≤x≤1.3, 0≤y≤1.3, and 0.9≤x+y≤1.3; 0.9≤a≤1.5, 0≤b≤0.5, and 0.9≤a+b≤1.5; 0≤c≤0.5; 3≤z≤5; A includes one or more of Na, K, and Mg; Me includes one or more of Mn, Fe, Co, and Ni; M includes one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; X includes one or more of S, Si, Cl, B, C, and N; Y includes one or more of O and F. Specifically, olivine-type phosphate active substances include one or more of LiFePO4, LiMnPO4, LiNiPO4, and LiCoPO4.

[0116] For example, the general formula of a spinel-structured positive electrode active material is Li x A y Mn a M 2-a Y z Wherein, 0≤x≤2, 0≤y≤1, and 0.9≤x+y≤2; 0.5≤a≤2; 3≤z≤5; A includes one or more of Na, K, and Mg; M includes one or more of Ni, Co, B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; Y includes one or more of O and F. Specifically, the positive electrode active materials with spinel structure include LiMn2O4 and LiNi. 0.5 Mn 1.5 O4, LiCr 0.3 Mn 1.7 O4, Li 1.1 Al 0.1 Mn 1.9 O4, Li2Mn2O4 and Li 1.5 One or more of Mn2O4.

[0117] During the charging and discharging process, active ions such as Li undergo insertion / extraction and consumption, resulting in varying molar Li content in the battery cell at different discharge states. In the embodiments of this application regarding the positive electrode active material, the molar Li content refers to the initial state of the material, i.e., the state before feeding. After charge-discharge cycles, the molar Li content may change when the positive electrode active material is applied to the battery system.

[0118] In the embodiments of this application, the molar content of oxygen (O) in the positive electrode active materials is only a theoretical value. Oxygen release from the crystal lattice will cause the molar content of oxygen (O) to change. In reality, the molar content of oxygen (O) will fluctuate.

[0119] In some embodiments, the positive electrode active material layer may optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0120] In some embodiments, the positive electrode active material layer may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0121] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0122] [Negative electrode plate]

[0123] In some implementations, the battery cell also includes a negative electrode.

[0124] In some embodiments, the negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector and comprising a negative electrode active material. For example, the negative current collector has two surfaces opposite each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative current collector.

[0125] The negative electrode active material may be any negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include, but is not limited to, at least one of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may include at least one of elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy materials. The tin-based material may include at least one of elemental tin, tin oxide, and tin alloy materials.

[0126] In some embodiments, the negative electrode film layer may optionally include a negative electrode conductive agent. This application does not impose particular limitations on the type of negative electrode conductive agent. As an example, the negative electrode conductive agent may include at least one selected from superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, based on the total weight of the negative electrode film layer, the mass percentage content of the negative electrode conductive agent is ≤5 wt%.

[0127] In some embodiments, the negative electrode film layer may optionally include a negative electrode binder. This application does not impose particular limitations on the type of negative electrode binder. As an example, the negative electrode binder may include at least one of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS). In some embodiments, the mass percentage of the negative electrode binder is ≤5 wt% based on the total weight of the negative electrode film layer.

[0128] In some embodiments, the negative electrode film may optionally include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC-Na), PTC thermistor materials, etc. In some embodiments, the mass percentage of the other additives is ≤2 wt% based on the total weight of the negative electrode film.

[0129] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. As an example of a metal foil, copper foil may be used. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one surface of the polymeric material substrate. As an example, the metal material may include at least one of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymeric material substrate may include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0130] The negative electrode film layer is typically formed by coating a negative electrode slurry onto a negative electrode current collector, followed by drying and cold pressing. The negative electrode slurry is typically formed by dispersing a negative electrode active material, optional conductive agent, optional binder, and other optional additives in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP) or deionized water, but is not limited to these.

[0131] The negative electrode sheet does not exclude other additional functional layers besides the negative electrode film layer. For example, in some embodiments, the negative electrode sheet described in this application further includes a conductive undercoat layer (e.g., composed of a conductive agent and an adhesive) sandwiched between the negative electrode current collector and the negative electrode film layer and disposed on the surface of the negative electrode current collector. In other embodiments, the negative electrode sheet described in this application further includes a protective layer covering the surface of the negative electrode film layer.

[0132] Electrolyte

[0133] In some implementations, the battery cell may also include an electrolyte.

[0134] During the charging and discharging process of a single battery cell, active ions repeatedly insert and extract between the positive and negative electrode plates, while the electrolyte acts as a conductor for these active ions. The embodiments of this application do not impose any particular restrictions on the type of electrolyte; it can be selected according to actual needs.

[0135] The electrolyte comprises an electrolyte salt and a solvent. The types of electrolyte salt and solvent are not specifically limited and can be selected according to actual needs.

[0136] When the battery cell in the embodiments of this application is a lithium-ion battery, as an example, the electrolyte salt may include, but is not limited to, at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0137] When the battery cell in the embodiments of this application is a sodium-ion battery, as an example, the electrolyte salt may include, but is not limited to, at least one of sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium bis(fluorosulfonyl)imide (NaFSI), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalate borate (NaDFOB), sodium dioxalate borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalate phosphate (NaDFOP), and sodium tetrafluorooxalate phosphate (NaTFOP).

[0138] As an example, the solvent may include, but is not limited to, at least one of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl ester carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0139] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, and additives that improve battery low-temperature power performance.

[0140] In some embodiments, the positive electrode, the separator, and the negative electrode can be fabricated into an electrode assembly using a winding process and / or a stacking process.

[0141] In some embodiments, the battery cell may include an outer packaging. This outer packaging can be used to encapsulate the electrode assembly and electrolyte described above.

[0142] In some embodiments, the outer packaging of the battery cell can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the battery cell can also be a soft package, such as a pouch. The material of the soft package can be plastic, such as at least one of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0143] This application does not impose any particular limitation on the shape of the battery cell; it can be cylindrical, square, or any other arbitrary shape. Figure 1 The example shown is a square-structured battery cell 5.

[0144] In some implementations, such as Figure 2 As shown, the outer packaging may include a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates enclosing a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 is used to cover the opening to close the receiving cavity. The positive electrode sheet, negative electrode sheet, and separator may be formed into an electrode assembly 52 by a winding process and / or a stacking process. The electrode assembly 52 is encapsulated in the receiving cavity. Electrolyte is immersed in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the battery cell 5 may be one or more, which can be adjusted according to requirements.

[0145] The method for preparing the battery cell of this application is well known. In some embodiments, a positive electrode, a separator, a negative electrode, and an electrolyte can be assembled to form a battery cell. As an example, the positive electrode, separator, and negative electrode can be formed into an electrode assembly through a winding process and / or a stacking process. The electrode assembly is placed in an outer packaging, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping processes, a battery cell is obtained.

[0146] In some embodiments of this application, the battery cells according to this application can be assembled into a battery module. The number of battery cells contained in the battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module.

[0147] Figure 3 This is a schematic diagram of battery module 4 as an example. Figure 3 As shown, in battery module 4, multiple battery cells 5 can be arranged sequentially along the length of battery module 4. Of course, they can also be arranged in any other manner. Furthermore, these multiple battery cells 5 can be fixed in place using fasteners.

[0148] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple battery cells 5 are received.

[0149] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0150] Figure 4 and Figure 5 This is a schematic diagram of battery pack 1 as an example. Figure 4 and Figure 5As shown, the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3. The upper body 2 covers the lower body 3, forming a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0151] The battery in the embodiments of this application may include one or more battery cells. When the battery includes multiple battery cells, the battery may include a battery module or a battery pack.

[0152] Electrical appliances

[0153] A fifth aspect of this application provides an electrical device, which includes at least one of the battery cell, battery module, or battery pack described in this application. The battery cell, battery module, or battery pack can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device may be, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0154] The electrical device can be configured to use individual battery cells, battery modules, or battery packs according to its usage requirements.

[0155] Figure 6 This is a schematic diagram of an example electrical device 6. This electrical device 6 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of this electrical device 6, a battery pack or battery module can be used.

[0156] Another example of an electrical device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use a single battery cell as their power source.

[0157] Example

[0158] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0159] Preparation of Lithium-ion Batteries in Examples and Comparative Cases

[0160] 1. Preparation of positive electrode sheet

[0161] Aluminum foil with a thickness of 12μm was used as the positive electrode current collector.

[0162] LiNi, the positive electrode active material 0.5 Co 0.2 Mn 0.3 O2, conductive agent carbon black, and binder polyvinylidene fluoride (PVDF) are mixed in a weight ratio of 97.5:1.4:1.1 in an appropriate amount of solvent N-methylpyrrolidone (NMP) to form a uniform positive electrode slurry. The positive electrode slurry is uniformly coated on the surface of the positive electrode current collector aluminum foil, and after drying and cold pressing, the positive electrode sheet is obtained.

[0163] 2. Preparation of negative electrode sheet

[0164] A copper foil with a thickness of 8μm was used as the negative electrode current collector.

[0165] Artificial graphite (anode active material), styrene-butadiene rubber (SBR) (binder), sodium carboxymethyl cellulose (CMC-Na) (thickener), and carbon black (Super P) (conductive agent) are mixed thoroughly in an appropriate amount of deionized water at a weight ratio of 96.2:1.8:1.2:0.8 to form a uniform negative electrode slurry. The negative electrode slurry is then uniformly coated onto the surface of copper foil (anode current collector), and after drying and cold pressing, a negative electrode sheet is obtained.

[0166] 3. Separating membrane

[0167] (1) Preparation of metal-organic frameworks (MOFs)

[0168] Materials containing metal ions and organic ligands were mixed, and then N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner and then transferred to an oven for reaction. The reactants were then centrifuged and soaked in N,N-dimethylformamide for 5 times. The mixture was then soaked in ethanol for 8 hours, centrifuged 4 times, and dried under vacuum at 60°C for 6 hours to prepare metal-organic frameworks (MOFs) with metal ions as the metal center and organic ligands.

[0169] (2) Chelating metal-organic frameworks

[0170] Weigh the chelate and the metal-organic framework (MOF) compounds synthesized in step 1. Weigh 500 mL of N,N-dimethylformamide as solvent and add it to a microchannel reactor at a preset reaction mass ratio of 1:100 for continuous synthesis. The reaction time is 5 min and the temperature is 45 °C to obtain the composite material.

[0171] (3) Preparation of the separating membrane

[0172] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and then the CCS slurry containing the composite material was uniformly coated onto polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining a release membrane. The basis weight of the functional layer was 2±0.1g / m². 2 .

[0173] 4. Preparation of electrolyte

[0174] In an environment with a water content of less than 10 ppm, the organic solvents ethylene carbonate (EC) and diethyl carbonate (DMC) are mixed at a volume ratio of 1:1 to obtain the electrolyte solvent. Then, the lithium salt is mixed with the mixed solvent to prepare an electrolyte with a lithium salt concentration of 1 mol / L.

[0175] 5. Preparation of battery cells

[0176] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a separator between the positive and negative electrodes. The electrode assembly is then wound up. The electrode assembly is placed in an outer packaging shell, dried, and then injected with electrolyte. After vacuum sealing, settling, formation, and shaping, a lithium-ion battery is obtained.

[0177] Example 1

[0178] The lithium-ion battery was prepared using the above steps, wherein the preparation steps of the separator in Example 1 are as follows:

[0179] (1) Preparation of metal-organic frameworks (MOFs)

[0180] 100g of zirconium chloride and 60g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The reaction was carried out at 125℃ for 15h. After centrifugation, the reactants were soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. The mixture was centrifuged 4 times and then vacuum dried at 60℃ for 6h to obtain zirconium ions (Zr). 4+ Metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0181] (2) Chelating metal-organic frameworks

[0182] Weigh 0.1g of octanoyl hydroxamic acid and 10g of the metal-organic framework compound MOFs synthesized in step (1). Weigh 500mL of N,N-dimethylformamide as solvent and add it to the microchannel reactor at a preset reaction mass ratio of 1:100 for continuous synthesis. The reaction time is 5min and the temperature is 45℃ to obtain the composite material.

[0183] (3) Preparation of the separating membrane

[0184] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and then the CCS slurry containing the composite material was uniformly coated onto polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining a release membrane. The basis weight of the functional layer was 2±0.1g / m². 2 .

[0185] Comparative Example 1

[0186] A lithium-ion battery was prepared using a method similar to that of Example 1, except that the separator was prepared using the following steps:

[0187] CCS slurry (alumina aqueous solution with a solid content of 45%) was uniformly coated on both surfaces of a polypropylene (PP) substrate (12μm), and the CCS slurry was dried to form a functional layer to obtain a release film.

[0188] Comparative Example 2

[0189] The lithium-ion battery was prepared using a method similar to that of Example 1, except that the metal-organic framework compound and chelate of the separator were mixed in a physical mixing manner. The preparation steps included:

[0190] (1) Preparation of metal-organic frameworks (MOFs)

[0191] 100g of zirconium chloride and 60g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The reaction was carried out at 125℃ for 15h. After centrifugation, the reactants were soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. The mixture was centrifuged 4 times and then vacuum dried at 60℃ for 6h to obtain zirconium ions (Zr). 4+ Metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0192] (2) Chelating metal-organic frameworks

[0193] 0.1g of octanoyl hydroxamic acid and 10g of the metal-organic framework compound (MOF) synthesized in step (1) were weighed and mixed to prepare a composite material.

[0194] (3) Preparation of the separating membrane

[0195] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0196] Comparative Example 3

[0197] A lithium-ion battery was prepared using a method similar to that of Example 1. The difference from Example 1 is that the separator only comprises a metal-organic framework compound and does not include chelates. The preparation steps of the separator include:

[0198] (1) Preparation of metal-organic frameworks (MOFs)

[0199] 100g of zirconium chloride and 60g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The reaction was carried out at 125℃ for 15h. After centrifugation, the reactants were soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. The mixture was centrifuged 4 times and then vacuum dried at 60℃ for 6h to obtain zirconium ions (Zr). 4+ A composite material was prepared by using metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0200] (2) Preparation of the separating membrane

[0201] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0202] Comparative Example 4

[0203] A lithium-ion battery was prepared using a method similar to that in Example 1. The difference from Example 1 is that the separator only includes chelates and does not include metal-organic framework compounds. The preparation steps of the separator include:

[0204] Weigh 2g of octanoic acid and add it to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%). Stir well and coat the CCS slurry containing the composite material evenly on polypropylene (PP) (thickness of 12μm) to form a functional layer and obtain a release membrane.

[0205] Example 2

[0206] A lithium-ion battery was prepared using a method similar to that of Example 1, except that the types of metal ions in the functional layer of the separator were adjusted.

[0207] In Example 2-1, the material containing metal ions was replaced by cobalt chloride instead of zirconium chloride.

[0208] In Example 2-2, the material containing metal ions was replaced by bismuth chloride instead of zirconium chloride.

[0209] In Examples 2-3, the material containing metal ions was replaced by manganese chloride instead of zirconium chloride.

[0210] Examples 3-1 and 3-2

[0211] Lithium-ion batteries were prepared using a method similar to that of Example 1, except that the types of organic ligands in the functional layers of the separator were adjusted.

[0212] Examples 4-1 and 4-2

[0213] Lithium-ion batteries were prepared using a method similar to that of Example 1, except that the types of chelates in the substrate of the separator were adjusted.

[0214] Examples 5-1 to 5-9

[0215] Lithium-ion batteries were prepared using a method similar to that of Example 1, except that the particle size of the composite material in the substrate of the separator was adjusted.

[0216] Example 5-1

[0217] (1) Preparation of metal-organic frameworks (MOFs)

[0218] 100g of zirconium chloride and 55g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The reaction was carried out at 125℃ for 15h. After centrifugation, the reactants were soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. The mixture was centrifuged 4 times and then dried under vacuum at 60℃ for 6h to obtain zirconium ions (Zr). 4+ Metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0219] (2) Chelating metal-organic frameworks

[0220] 0.1 g of octanoyl hydroxamic acid and 10 g of the metal-organic framework compound (MOF) synthesized in step 1 were weighed out. 500 mL of N,N-dimethylformamide was weighed out as a solvent and added to a microchannel reactor at a preset mass ratio of 1:100 for continuous synthesis. The reaction time was 5 min and the temperature was 45 °C to obtain the composite material.

[0221] (3) Preparation of the separating membrane

[0222] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0223] Example 5-2

[0224] (1) Preparation of metal-organic frameworks (MOFs)

[0225] 100g of zirconium chloride and 49g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The mixture was reacted at 125℃ for 15h. The reactants were then centrifuged and soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times. The mixture was then soaked in 20g of ethanol for 8h, centrifuged 4 times, and dried under vacuum at 60℃ for 6h to prepare metal-organic frameworks (MOFs) with zirconium ions (Zr4+) as the metal center and 1,4-cyclohexanedicarboxylic acid as the organic ligand.

[0226] (2) Chelating metal-organic frameworks

[0227] Weigh 0.1g of octanoyl hydroxamic acid and 10g of the metal-organic framework compound MOFs synthesized in step (1). Weigh 500mL of N,N-dimethylformamide as solvent and add it to the microchannel reactor at a preset reaction mass ratio of 1:100 for continuous synthesis. The reaction time is 5min and the temperature is 45℃ to obtain the composite material.

[0228] (3) Preparation of the separating membrane

[0229] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0230] Example 5-3

[0231] (1) Preparation of metal-organic frameworks (MOFs)

[0232] 100g of zirconium chloride and 42g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The mixture was reacted at 125℃ for 15h. The reactants were then centrifuged, soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. The mixture was centrifuged 4 times and then vacuum dried at 60℃ for 6h to obtain zirconium ions (Zr). 4+ Metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0233] (2) Chelating metal-organic frameworks

[0234] Weigh 0.1g of octanoyl hydroxamic acid and 10g of the metal-organic framework compound MOFs synthesized in step (1). Weigh 500mL of N,N-dimethylformamide as solvent and add it to the microchannel reactor at a preset reaction mass ratio of 1:100 for continuous synthesis. The reaction time is 5min and the temperature is 45℃ to obtain the composite material.

[0235] (3) Preparation of the separating membrane

[0236] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0237] Example 5-4

[0238] 100g of zirconium chloride and 36g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The mixture was reacted at 125℃ for 15h. The reactants were then centrifuged, soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. After centrifugation 4 times, the mixture was vacuum dried at 60℃ for 6h to obtain zirconium ions (Zr). 4+ Metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0239] (2) Chelating metal-organic frameworks

[0240] Weigh 0.1g of octanoyl hydroxamic acid and 10g of the metal-organic framework compound MOFs synthesized in step (1). Weigh 500mL of N,N-dimethylformamide as solvent and add it to the microchannel reactor at a preset reaction mass ratio of 1:100 for continuous synthesis. The reaction time is 5min and the temperature is 45℃ to obtain the composite material.

[0241] (3) Preparation of the separating membrane

[0242] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0243] Example 5-5

[0244] 100g of zirconium chloride and 55g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The reaction was carried out at 125℃ for 13h. After centrifugation, the reactants were soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. The mixture was centrifuged 4 times and then vacuum dried at 60℃ for 6h to obtain zirconium ions (Zr). 4+ Metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0245] (2) Chelating metal-organic frameworks

[0246] Weigh 0.1g of octanoyl hydroxamic acid and 10g of the metal-organic framework compound MOFs synthesized in step (1). Weigh 500mL of N,N-dimethylformamide as solvent and add it to the microchannel reactor at a preset reaction mass ratio of 1:100 for continuous synthesis. The reaction time is 5min and the temperature is 45℃ to obtain the composite material.

[0247] (3) Preparation of the separating membrane

[0248] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0249] Examples 5-6

[0250] 100g of zirconium chloride and 55g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The reaction was carried out at 125℃ for 11h. After centrifugation, the reactants were soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. The mixture was centrifuged 4 times and then vacuum dried at 60℃ for 6h to obtain zirconium ions (Zr). 4+Metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0251] (2) Chelating metal-organic frameworks

[0252] Weigh 0.1g of octanoyl hydroxamic acid and 10g of the metal-organic framework compound MOFs synthesized in step (1). Weigh 500mL of N,N-dimethylformamide as solvent and add it to the microchannel reactor at a preset reaction mass ratio of 1:100 for continuous synthesis. The reaction time is 5min and the temperature is 45℃ to obtain the composite material.

[0253] (3) Preparation of the separating membrane

[0254] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0255] Examples 5-7

[0256] 100g of zirconium chloride and 39g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The reaction was carried out at 125℃ for 15h. After centrifugation, the reactants were soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. The mixture was centrifuged 4 times and then dried under vacuum at 60℃ for 6h to obtain zirconium ions (Zr). 4+ Metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0257] (2) Chelating metal-organic frameworks

[0258] Weigh 0.1g of octanoyl hydroxamic acid and 10g of the metal-organic framework compound MOFs synthesized in step (1). Weigh 500mL of N,N-dimethylformamide as solvent and add it to the microchannel reactor at a preset reaction mass ratio of 1:100 for continuous synthesis. The reaction time is 5min and the temperature is 45℃ to obtain the composite material.

[0259] (3) Preparation of the separating membrane

[0260] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0261] Examples 5-8

[0262] 100g of zirconium chloride and 55g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The reaction was carried out at 125℃ for 11h. After centrifugation, the reactants were soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. The mixture was centrifuged 4 times and then vacuum dried at 60℃ for 6h to obtain zirconium ions (Zr). 4+ Metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0263] (2) Chelating metal-organic frameworks

[0264] Weigh 0.1g of octanoyl hydroxamic acid and 10g of the metal-organic framework compound MOFs synthesized in step (1). Weigh 500mL of N,N-dimethylformamide as solvent and add it to the microchannel reactor at a preset reaction mass ratio of 1:100 for continuous synthesis. The reaction time is 5min and the temperature is 45℃ to obtain the composite material.

[0265] (3) Preparation of the separating membrane

[0266] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0267] Examples 5-9

[0268] 100g of zirconium chloride and 55g of 1,4-cyclohexanedicarboxylic acid were mixed, and then 45g of N,N-dimethylformamide was added to the system. The mixture was stirred and dissolved, then transferred to a polytetrafluoroethylene reactor liner, and then transferred to an oven. The reaction was carried out at 125℃ for 10h. After centrifugation, the reactants were soaked in 30g of N,N-dimethylformamide for 6h, repeated 5 times, and then soaked in 20g of ethanol for 8h. The mixture was centrifuged 4 times and then vacuum dried at 60℃ for 6h to obtain zirconium ions (Zr). 4+ Metal-organic frameworks (MOFs) with a metal center and 1,4-cyclohexanedicarboxylic acid as an organic ligand.

[0269] (2) Chelating metal-organic frameworks

[0270] Weigh 0.1g of octanoyl hydroxamic acid and 10g of the metal-organic framework compound MOFs synthesized in step (1). Weigh 500mL of N,N-dimethylformamide as solvent and add it to the microchannel reactor at a preset reaction mass ratio of 1:100 for continuous synthesis. The reaction time is 5min and the temperature is 45℃ to obtain the composite material.

[0271] (3) Preparation of the separating membrane

[0272] 2g of the composite material was weighed and added to 500g of CCS slurry (alumina aqueous solution with a solid content of 45%), stirred evenly, and the CCS slurry containing the composite material was uniformly coated on polypropylene (PP) (12μm thick) to form a functional layer, thus obtaining the isolation membrane.

[0273] Examples 6-1 to 6-4

[0274] Lithium-ion batteries were prepared using a method similar to that of Example 1, except that the mass ratio of chelates and MOFs in the substrate of the separator was adjusted.

[0275] Examples 7-1 to 7-4

[0276] Lithium-ion batteries were prepared using a method similar to that of Example 1, except that the mass content of the composite material in the separator was adjusted.

[0277] Examples 8-1 and 8-2

[0278] Lithium-ion batteries were prepared using a method similar to that of Example 1, except that the coating weight of the functional layer in the separator was adjusted.

[0279] The relevant parameters for the embodiments and comparative examples are shown in Table 1.

[0280] Test section

[0281] 1. Cycle performance testing of lithium-ion batteries

[0282] A lithium-ion battery is charged at 25°C with a constant current of 2C to 4.25V, then charged at a constant voltage of 4.25V to a current of 0.05C, and then discharged at a constant current of 1C to 2.8V. This constitutes one charge-discharge cycle. Using the initial discharge capacity as 100%, calculate the capacity retention rate after 500 cycles. Capacity retention rate (%) after 500 cycles = (Discharge capacity of the 500th cycle / Initial discharge capacity) × 100%.

[0283] 2. K-value test

[0284] The K value can be used to describe the self-discharge rate of a battery cell. It can be calculated by dividing the open-circuit voltage difference between two tests by the time interval Δt between the two voltage tests. The formula is: K = (OCV2 - OCV1) / Δt. That is, K can represent the voltage drop per unit time. Generally speaking, the larger the K value, the faster or larger the open-circuit voltage drops, and there may be a micro-short circuit in the battery cell.

[0285] 3. ICP test for metal ion content in electrolyte

[0286] ICP instrument model: ICAP 7200ICP-OES, manufactured by ThermoFisher Technologies (formerly ThermoFisher).

[0287] Test conditions: The sample must be an electrolyte liquid. If it contains solid particles, it must be digested with acid or filtered to remove the solid particles. The range of the elements to be measured must be within the range of the standard curve. If it exceeds the range, the sample must be diluted.

[0288] Main operating procedures: 1. Test the standard curve; 2. Dilute the sample to be tested; 3. Test the diluted sample; 4. Calculate and process the data to obtain the concentration of the element to be tested.

[0289] Electrolyte from a fresh battery cell was taken as a sample and analyzed by inductively coupled plasma optical emission spectrometry (ICP). A fresh battery cell refers to one that has undergone no more than 10 cycles.

[0290] Test Results

[0291] The test results are shown in Table 1.

[0292] Table 1

[0293]

[0294]

[0295] In Table 1, the K value represents the K value obtained from the test when the time interval is 14 days.

[0296] As shown in Table 1, compared to Comparative Example 1, Comparative Example 3, by adding MOF materials to the separator, can reduce metal impurity ions, but the effect is relatively small. Comparative Example 4, by adding a chelating agent to the separator, can reduce metal impurity ions, but the effect is relatively small. Comparative Example 2, by adding both MOF materials and a chelating agent to the separator, can reduce metal impurity ions, but the two work independently, and the effect on reducing metal impurity ions is relatively small.

[0297] The separator in this application embodiment comprises a composite material, which includes a metal-organic framework compound and a chelate interconnected with each other. The metal-organic framework compound is formed by coordination of metal ions and organic ligands, wherein the metal ions have a valence of divalent or higher, and the organic ligands include polycarboxylic acid structures. The metal-organic framework material can bind metal impurity ions through pore size and electrostatic synergy, and the chelate can further bind to the metal impurity ions through chelation, reducing the content of metal impurity ions in the electrolyte, thereby reducing the number of metal impurity ions migrating to the negative electrode, increasing the number of sites for active ion insertion in the negative electrode, and improving the reversible capacity of the battery cell; it also mitigates the risk of metal impurity ions precipitating on the surface of the negative electrode and forming metal dendrites, improving the reliability of the battery cell; and it can also reduce the self-discharge rate of the battery cell, improving its cycle performance.

[0298] Although illustrative embodiments have been demonstrated and described, those skilled in the art should understand that the above embodiments should not be construed as limiting the present application, and that changes, substitutions and modifications can be made to the embodiments without departing from the spirit, principles and scope of the present application.

Claims

1. A separating membrane comprising a substrate and a functional layer disposed on at least one side of the substrate, the functional layer comprising a composite material comprising a metal-organic framework compound and a chelate interconnected thereto, the metal-organic framework compound being formed by coordination of a metal ion and an organic ligand, the metal ion having a valence greater than or equal to divalent, the organic ligand comprising a polycarboxylic acid group, and the mass percentage ratio of the chelate to the metal-organic framework compound being 0.01 to 0.10:1 based on the mass of the composite material.

2. The separator according to claim 1, wherein, The valence of the metal ion is greater than or equal to tetravalent.

3. The separator according to claim 2, wherein, The valence of the metal ion is greater than or equal to pentavalent.

4. The separator membrane according to claim 3, wherein, The valence of the metal ion is greater than or equal to hexavalent.

5. The separator membrane according to claim 1, wherein, The metal ions include Zr. 2+ Zr 3+ Zr 4+ Bi 3+ Bi 5+ Zn 2+ Hf 4+ Co 2+ Co 3+ Mn 4+ Mn 5+ and Mn 6+ At least one of them.

6. The separator according to claim 5, wherein, The metal ions include Zr. 4+ Bi 5+ Hf 4+ Mn 4+ Mn 5+ and Mn 6+ At least one of them.

7. The separator according to claim 6, wherein, The metal ions include Bi. 5+ Mn 5+ and Mn 6+ At least one of them.

8. The separator according to claim 1, wherein, The organic ligand includes at least one selected from phthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, 4,4'-sulfonyl dibenzoic acid, and 4,4'-dicarboxylic diphenyl ether.

9. The separator according to claim 1, wherein, The chelate includes at least one of a carboxylic acid group, a phosphonic acid group, and an octanoyl hydroxamic acid.

10. The separator according to claim 9, wherein, The chelate containing the carboxylic acid group includes at least one of ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, and diethylenetriaminepentaacetic acid.

11. The separator according to claim 9, wherein, The chelates containing the phosphonic acid group include one or more of hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, triethylenetetraminehexamethylenephosphonic acid, bis(1,6-hexylene)triaminepentamethylenephosphonic acid, and polyaminopolyethertetramethylenephosphonic acid.

12. The separator according to claim 1, wherein, The volume average particle size Dv50 of the composite material is 100 nm to 300 nm; and / or The average pore size of the composite material is from 0.50 nm to 1.10 nm.

13. The separator membrane according to claim 1, wherein, Based on the mass of the functional layer, the mass percentage of the composite material is 0.1% to 1.0%.

14. The separator according to claim 1, wherein, The functional layer also includes heat-resistant particles.

15. The separator membrane according to claim 14, wherein, The heat-resistant particles comprise less than or equal to 30% of the functional layer by mass.

16. The separator membrane according to any one of claims 1 to 15, wherein, The thickness of the functional layer is 0.1 μm to 4 μm; and / or The coating basis weight of the functional layer is 1 g / m². 2 Up to 3g / m 2 .

17. The separator according to claim 16, wherein, The thickness of the functional layer is 0.5 μm to 3 μm.

18. The separator membrane according to claim 1, wherein, The thickness of the substrate is less than or equal to 16 μm.

19. The separator membrane according to claim 18, wherein, The thickness of the substrate is 5 μm to 14 μm.

20. A composite material for a separator membrane, comprising a metal-organic framework compound and a chelate connected to each other, the metal-organic framework compound being formed by coordination of a metal ion and an organic ligand, the metal ion having a valence greater than or equal to divalent, the organic ligand comprising a polycarboxylic acid group, wherein the mass percentage of the chelate to the mass percentage of the metal-organic framework compound is 0.01 to 0.10:1 based on the mass of the composite material.

21. The composite material according to claim 20, wherein, The valence of the metal ion is greater than or equal to tetravalent.

22. The composite material according to claim 21, wherein, The valence of the metal ion is greater than or equal to pentavalent.

23. The composite material according to claim 22, wherein, The valence of the metal ion is greater than or equal to hexavalent.

24. The composite material according to claim 20, wherein, The metal ions include Zr. 2+ Zr 3+ Zr 4+ Bi 3+ Bi 5+ Zn 2+ Hf 4+ Co 2+ Co 3+ Mn 4+ Mn 5+ and Mn 6+ At least one of them.

25. The composite material according to claim 24, wherein, The metal ions include Zr. 4+ Bi 5+ Hf 4+ Mn 4+ Mn 5+ and Mn 6+ At least one of them.

26. The composite material according to claim 25, wherein, The metal ions include Bi. 5+ Mn 5+ and Mn 6+ At least one of them.

27. The composite material according to claim 20, wherein, The organic ligand includes at least one selected from phthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid, 4,4'-sulfonyl dibenzoic acid, and 4,4'-dicarboxylic diphenyl ether.

28. The composite material according to claim 20, wherein, The chelate includes at least one of a carboxylic acid group, a phosphonic acid group, and an octanoyl hydroxamic acid.

29. The composite material according to claim 28, wherein, The chelate containing the carboxylic acid group includes at least one of ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, and diethylenetriaminepentaacetic acid.

30. The composite material according to claim 28, wherein, The chelates containing the phosphonic acid group include one or more of hydroxyethylidene-1,1-diphosphonic acid, aminotrimethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, triethylenetetraminehexamethylenephosphonic acid, bis(1,6-hexylene)triaminepentamethylenephosphonic acid, and polyaminopolyethertetramethylenephosphonic acid.

31. The composite material according to any one of claims 20 to 30, wherein, The volume average particle size Dv50 of the composite material is 100 nm to 300 nm; and / or The average pore size of the composite material is from 0.50 nm to 1.10 nm.

32. A battery comprising a separator, said separator being the separator as claimed in any one of claims 1 to 19; or said separator comprising a substrate and a functional layer disposed on at least one side of the substrate, said functional layer comprising a composite material as claimed in any one of claims 20 to 31.

33. An electrical device comprising the battery as described in claim 32.

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