A polymer and its use

Abstract

A polymer and its use. The polymer comprises at least a structural formula shown in Formula 1; in Formula 1, R1 is selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C60 aryl; R2 is selected from substituted or unsubstituted polyether group, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 alkoxy, *-b1-S-S-b2-*; b1, b2 are each independently selected from substituted or unsubstituted C2-C15 alkanyl, substituted or unsubstituted C6-C60 aryl; R3 is an ionic liquid group; n is an integer greater than or equal to 1. The special molecular structure of the polymer makes it have excellent room temperature ionic conductivity when applied to polymer electrolyte.

Description

Technical Field

[0001] This application relates to a polymer and its applications, belonging to the field of energy technology. Background Technology

[0002] In the 1990s, Sony successfully industrialized lithium-ion batteries. Over the decades, lithium-ion batteries have permeated various industries, including 3C electronics, electric vehicles, energy storage, and aerospace. Currently, lithium-ion batteries use organic electrolytes such as ethers and carbonates as the medium for lithium-ion transport. However, organic electrolytes present safety issues such as volatility, leakage, and flammability / explosion. Furthermore, during cycling, uneven lithium deposition at the negative electrode interface can lead to the formation and growth of lithium dendrites. These dendrites can puncture the battery separator, causing short circuits and potentially leading to thermal runaway or fire.

[0003] Inorganic solid-state electrolytes are widely used to address the safety issues of lithium-ion batteries due to their excellent electrochemical stability, thermal stability, and good mechanical strength. However, inorganic solid-state electrolytes suffer from high brittleness, making them prone to cracking during application, which can lead to increased internal resistance or even battery failure. Furthermore, the poor solid-solid interface between the inorganic solid-state electrolyte and the positive and negative electrodes can also result in high internal resistance in lithium-ion batteries, leading to a rapid decline in battery capacity and performance.

[0004] To overcome the shortcomings of inorganic solid electrolytes, polymer electrolytes have emerged. Polymer electrolytes have good processability, flexibility and good mechanical strength, which can make up for the performance defects of inorganic solid electrolytes. However, they usually have low room temperature ionic conductivity. Summary of the Invention

[0005] This application provides a polymer whose special molecular structure enables it to exhibit excellent room-temperature ionic conductivity when applied to polymer electrolytes.

[0006] This application provides a polymer electrolyte with excellent room temperature ionic conductivity, which can be widely used in batteries to improve the electrochemical performance of batteries.

[0007] This application provides a separator comprising the aforementioned polymer or polymer electrolyte, which, when applied to a battery, can improve the battery's electrochemical performance.

[0008] The battery of this application has excellent electrochemical performance because it includes any of the above-mentioned polymer, polymer electrolyte and separator.

[0009] This application provides a polymer, wherein the polymer comprises at least the structural formula shown in Formula 1;

[0010] Formula 1;

[0011] In Formula 1, R1 is selected from substituted or unsubstituted C1-C30 alkyl groups and substituted or unsubstituted C6-C60 aryl groups;

[0012] R2 is selected from substituted or unsubstituted polyether groups, substituted or unsubstituted C1-C30 alkyl groups, substituted or unsubstituted C1-C30 alkoxy groups, and *-b1-SS-b2-*; b1 and b2 are each independently selected from substituted or unsubstituted C2-C15 chain alkyl groups and substituted or unsubstituted C6-C60 aryl groups; R3 is an ionic liquid group.

[0013] n≥1 and is an integer.

[0014] The polymer as described above, wherein,

[0015] When the polymer includes multiple structures of Formula 1, R3 is selected from the same ionic liquid group.

[0016] The polymer as described above, wherein when the polymer includes a plurality of the structural formulas of Formula 1, at least one of the following is satisfied:

[0017] a) The R1 in multiple of the structural formulas of Formula 1 is selected from the same group;

[0018] b) The R2 in multiple of the structural formulas of Formula 1 is selected from the same group.

[0019] The polymer as described above, wherein R3 is selected from one of imidazole ionic liquid groups, pyridine ionic liquid groups, quaternary ammonium ionic liquid groups, or quaternary phosphonium ionic liquid groups.

[0020] The polymer as described above, wherein R3 is selected from any one of the following groups;

[0021]

[0022] Wherein, R4 is selected from substituted or unsubstituted C1-C30 alkyl groups and substituted or unsubstituted C1-C30 alkoxy groups; R5 is selected from substituted or unsubstituted C1-C10 alkyl groups; A is selected from BF4. - PF6 - TFSI - OTf - DCA - or TOS - .

[0023] The polymer as described above, wherein R2 is selected from any one of the following groups;

[0024]

[0025] Where n is a positive integer.

[0026] The polymers described above, wherein at least one of the following is satisfied:

[0027] a) R1 is a ring structure;

[0028] b) The R2 has a chain-like structure.

[0029] The polymer as described above, wherein,

[0030] The polymer is obtained by reacting an imine-based ionic liquid with a diisocyanate compound.

[0031] This application provides a polymer electrolyte, wherein the polymer electrolyte comprises a lithium salt and a polymer as described above.

[0032] The polymer electrolyte as described above, wherein the mass percentage of lithium salt in the polymer electrolyte is 5-30%, and the mass percentage of polymer is 70-95%.

[0033] This application provides a diaphragm, comprising a porous matrix and a polymer or polymer electrolyte as described above disposed in at least a portion of the surface of the porous matrix and / or at least a portion of the pores of the porous matrix.

[0034] This application provides a battery comprising the polymer described above;

[0035] Or, including polymer electrolytes as described above;

[0036] Or, including the diaphragm as described above.

[0037] The polymer of this application includes the structure shown in Formula 1. The ionic liquid groups and anionic groups in the polymer can interact well, thereby fixing the anions and enabling the lithium ions to dissociate rapidly, increasing the concentration of freely migrating lithium ions in the electrolyte, which is beneficial to improving the ionic conductivity and ion transference number of the polymer electrolyte. At the same time, the polymer has a relatively regular structure, and the ionic liquid can be dispersed relatively uniformly in the polymer, which is beneficial to improving the rapid conduction of lithium ions in the electrolyte, reducing the transport resistance of lithium ions, and improving the electrochemical performance of the polymer electrolyte.

[0038] The polymer electrolyte of this application includes the polymers described above. This polymer electrolyte has excellent room temperature ionic conductivity and mechanical strength, and can be widely used in batteries to improve the electrochemical performance of batteries.

[0039] The separator of this application includes the aforementioned polymer or polymer electrolyte, and therefore, when applied to a battery, it can improve the electrochemical performance of the battery.

[0040] The battery of this application has excellent electrochemical performance because it includes any of the above-mentioned polymer, polymer electrolyte and separator. Attached Figure Description

[0041] Figure 1 This is the infrared spectrum of the polymer in Example 1 of this application. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0043] A first aspect of this application provides a polymer, the polymer comprising at least the structural formula shown in Formula 1;

[0044] Formula 1;

[0045] In Formula 1, R1 is selected from substituted or unsubstituted C1-C30 alkyl groups and substituted or unsubstituted C6-C60 aryl groups; R2 is selected from substituted or unsubstituted polyether groups, substituted or unsubstituted C1-C30 alkoxy groups, substituted or unsubstituted C1-C30 alkyl groups, and *-b1-SS-b2-*; b1 and b2 are each independently selected from substituted or unsubstituted C2-C15 chain alkyl groups and substituted or unsubstituted aryl groups; R3 is an ionic liquid group.

[0046] n≥1 and is a positive integer.

[0047] Specifically, R1 is selected from substituted or unsubstituted C1-C30 alkyl groups (e.g., straight-chain alkyl, branched alkyl, cycloalkyl, substituted straight-chain alkyl, substituted branched alkyl, substituted cycloalkyl) and substituted or unsubstituted C6-C60 aryl groups (e.g., substituted phenyl, unsubstituted phenyl, substituted biphenyl, unsubstituted biphenyl).

[0048] R2 is selected from substituted or unsubstituted polyether groups (e.g., substituted chain polyether groups, unsubstituted chain polyether groups), substituted or unsubstituted C1-C30 alkyl groups (e.g., straight-chain alkyl, branched alkyl, cycloalkyl, substituted straight-chain alkyl, substituted branched alkyl, substituted cycloalkyl), substituted or unsubstituted C1-C30 alkoxy groups (e.g., substituted branched alkoxy, substituted straight-chain alkoxy, substituted cycloalkoxy, unsubstituted straight-chain alkoxy, unsubstituted branched alkoxy, unsubstituted cycloalkoxy), *-b1-SS-b2-* (b1 and b2 are each independently selected from substituted or unsubstituted C2-C15 chain alkyl groups, which can be straight-chain alkyl or branched alkyl; substituted or unsubstituted C6-C60 aryl groups, which can be unsubstituted phenyl, substituted phenyl, substituted biphenyl, unsubstituted biphenyl; * indicates the position connected to the main chain in Formula 1).

[0049] This application does not impose any particular limitation on the substituents in R1 and R2, and the substituents can be those commonly used in the art. Exemplarily, the substituents can be selected from substituted or unsubstituted C1-C30 alkyl groups, substituted or unsubstituted C2-C30 alkenyl groups, substituted or unsubstituted C3-30 alkynyl groups, ester groups, substituted or unsubstituted C1-C30 alkoxy groups, substituted or unsubstituted C6-C60 aryl groups, or halogens.

[0050] The ionic liquid group in R3 refers to an organic group containing both cations and anions.

[0051] n is the degree of aggregation, which is a positive integer; further, 50≤n≤800.

[0052] The polymer of this application includes the structure shown in Formula 1. The ionic liquid groups and anionic groups in this polymer can interact effectively, thereby immobilizing the anions and allowing lithium ions to dissociate rapidly. This increases the concentration of freely migrating lithium ions in the electrolyte, which is beneficial for improving the ionic conductivity and ion transference number of the polymer electrolyte. Simultaneously, the polymer has a relatively uniform structure, allowing the ionic liquid to be dispersed more evenly within the polymer, which is beneficial for improving the rapid conduction of lithium ions in the electrolyte, reducing lithium ion transport resistance, and improving the electrochemical performance of the polymer electrolyte. It is worth mentioning that the ionic liquid groups can also improve the flame retardant properties of the polymer, thus giving the polymer electrolyte containing this polymer excellent flame retardant properties, thereby improving the safety performance of the battery.

[0053] It is understood that in the polymer of this application, R1, R2, and R3 in the structure shown in Formula 1 can be selected from the same group or from different groups. That is, when the polymer includes multiple structures of Formula 1 (n≥2), R1 in multiple structures of Formula 1 can be the same or different, R2 in multiple structures of Formula 1 can be the same or different, and R3 in multiple structures of Formula 1 can be the same or different.

[0054] In some embodiments of this application, when the polymer includes multiple Formula 1 structures, R3 in the multiple Formula 1 structures is selected from the same ionic liquid group. The same ionic liquid group is beneficial to improve the uniformity of ion conduction and further improve the ionic conductivity of the polymer.

[0055] In some embodiments of this application, when the polymer includes multiple Formula 1 structures, R1 in the multiple Formula 1 structures is selected from the same group and R2 in the multiple Formula 1 structures is selected from the same group. The same group is beneficial to improve the structural uniformity of the polymer and further improve the mechanical properties and ionic conductivity of the polymer.

[0056] In some embodiments of this application, R3 is selected from one of imidazole ionic liquid groups, pyridine ionic liquid groups, quaternary ammonium ionic liquid groups, or quaternary phosphonium ionic liquid groups.

[0057] In this application, polymers including the aforementioned ionic liquid groups can exhibit superior room temperature ionic conductivity and flame retardant properties when applied to polymer electrolytes. Furthermore, the ionic liquids used to form the aforementioned ionic liquid groups are readily available and relatively inexpensive, which helps to save production costs.

[0058] Furthermore, R3 is selected from any one of the following groups;

[0059]

[0060] Wherein, R4 is selected from substituted or unsubstituted C1-C30 alkyl groups and substituted or unsubstituted C1-C30 alkoxy groups; R5 is selected from substituted or unsubstituted C1-C10 alkyl groups; A is selected from BF4. - PF6 - TFSI - OTf - DCA - or TOS - .

[0061] Specifically, the * in the above structural formula refers to the position where it is connected to the main chain shown in Formula 1.

[0062] R4 is selected from substituted or unsubstituted C1-C30 alkyl groups (e.g., substituted straight-chain alkyl, substituted branched alkyl, substituted cycloalkyl, unsubstituted branched alkyl, unsubstituted straight-chain alkyl, or unsubstituted cycloalkyl), and substituted or unsubstituted C1-C30 alkoxy groups (e.g., substituted straight-chain alkoxy, substituted cycloalkoxy, substituted branched alkoxy, unsubstituted cycloalkoxy, unsubstituted straight-chain alkoxy, or unsubstituted branched alkoxy); R5 is selected from substituted or unsubstituted C1-C10 alkyl groups (e.g., substituted straight-chain alkyl, substituted branched alkyl, substituted cycloalkyl, unsubstituted branched alkyl, unsubstituted straight-chain alkyl, or unsubstituted cycloalkyl).

[0063] The anionic groups can be formed by the dissociation of the corresponding salts. For example, tetrafluoroborate ions are obtained by the dissociation of lithium tetrafluoroborate, and hexafluorophosphate ions are obtained by the dissociation of lithium hexafluorophosphate. The structures of the anionic groups in this application are shown below:

[0064] .

[0065] This application does not impose any particular limitation on the substituents in R4 and R5, and the substituents can be those commonly used in the art. Exemplarily, the substituents can be selected from at least one of substituted or unsubstituted C1-C30 alkyl groups, substituted or unsubstituted C2-C30 alkenyl groups, substituted or unsubstituted C3-30 alkynyl groups, ester groups, substituted or unsubstituted C1-C30 alkoxy groups, substituted or unsubstituted C6-C60 aryl groups, and halogens.

[0066] When R3 is selected from the above-mentioned structural formula, it is possible to further reduce production costs while improving the electrochemical performance and flame retardant performance of the battery.

[0067] In some embodiments of this application, R2 is selected from any of the following groups, but is not limited to the structures shown below;

[0068]

[0069] In R2, n is the degree of aggregation, which can be a positive integer from 1 to 30. In this application, the degree of aggregation in each structural formula can be the same or different; * refers to the position connected to the main chain shown in Equation 1.

[0070] When R2 is selected from the above structural formula, the electrochemical performance of the battery can be further improved.

[0071] In some embodiments of this application, R1 has a cyclic structure. That is, R1 is selected from substituted or unsubstituted C1 to C30 cycloalkyl groups (e.g., substituted cycloalkyl or unsubstituted cycloalkyl).

[0072] When R1 has a cyclic structure, it helps to improve the rigidity and thermal properties of the polymer, thereby improving the mechanical properties and heat resistance of the polymer electrolyte and extending the battery's lifespan.

[0073] Furthermore, R2 has a chain structure. That is, R2 is selected from substituted or unsubstituted chain polyether groups (e.g., substituted linear polyether groups, substituted branched polyether groups, unsubstituted linear polyether groups, and unsubstituted branched polyether groups), substituted or unsubstituted C1~C30 chain alkoxy groups (e.g., substituted branched alkoxy groups and substituted linear alkoxy groups), and *-b1-SS-b2-* (b1 and b2 are each independently selected from C2~C15 chain alkyl groups, which are linear alkyl groups or branched alkyl groups).

[0074] In this application, when R2 has a chain structure, the transport performance of lithium ions between ionic liquid structures can be controlled, thereby improving the lithium ion transport efficiency of the polymer electrolyte.

[0075] In particular, when R1 is a cyclic structure and R2 is a chain structure in the polymer, the polymer has a structure that combines rigidity and flexibility, which can give the polymer electrolyte both excellent mechanical properties and lithium-ion transport performance, thereby improving the electrochemical performance of the battery and extending its service life.

[0076] This application does not impose any particular restrictions on the raw materials and preparation methods for the polymer. As long as the polymer meets the above-mentioned characteristics, the raw materials and manufacturing methods corresponding to the purpose can be freely selected.

[0077] In some embodiments of this application, the polymer is obtained by reacting an imine-based ionic liquid with a diisocyanate compound.

[0078] This application does not specifically limit the imine-based ionic liquid; it can be any ionic liquid containing an imine group commonly used in the field. Imine-based ionic liquids can be obtained commercially or prepared in the laboratory.

[0079] This application does not specifically limit the diisocyanate compounds. The diisocyanate compounds can be compounds commonly used in the art that contain two isocyanate groups. For example, the diisocyanate compounds can be selected from at least one of isophorone diisocyanate, diphenylmethane-4,4′-diisocyanate, terephthalic diisocyanate, 1,3-diisophenyl cyanate, toluene 2,6-diisocyanate, m-phenylenedimethyl isocyanate, toluene-2,4-diisocyanate, and 4,4′-diisocyanate dicyclohexylmethane.

[0080] In this application, an imine-based ionic liquid reacts with a diisocyanate compound, where the imine-based ionic liquid is used to form R2 and R3 groups, and the diisocyanate compound is used to form an R1 group.

[0081] The polymer prepared by the above process can not only produce polymers with excellent comprehensive properties, but also has a simple preparation method that is suitable for widespread application.

[0082] This application does not specifically limit the reaction conditions between the imine ionic liquid and the diisocyanate compound. Generally, the amount of diisocyanate compound used should not be less than the amount of imine ionic liquid used, mainly to ensure that the imine groups in the imine ionic liquid undergo complete chemical reaction. Furthermore, a moderate excess of isocyanate groups can form potential chemical reaction sites in the obtained polyurea polymer electrolyte, undergoing chemical cross-linking reactions with other components in the polymer electrolyte, thereby increasing the cross-linking density of the polyurea polymer electrolyte. Exemplarily, the remaining isocyanate groups can continue to react with compounds containing amine or hydroxyl groups to increase the cross-linking density of the polymer electrolyte; and a moderate excess of isocyanate groups can react with water, appropriately eliminating the adverse effects of moisture on the performance of the polyurea polymer electrolyte. In some embodiments, the molar ratio of imine groups in the imine ionic liquid to isocyanate groups in the diisocyanate compound can be 1:(1.0~1.2).

[0083] In some embodiments, when the reaction between the imino ionic liquid and the diisocyanate compound is carried out at a temperature of 40°C-80°C for 30 min-24 h, polymers with superior performance can be obtained. Furthermore, a catalyst can be added during the reaction between the imino ionic liquid and the diisocyanate compound. The catalyst can be an organotin catalyst or an alkanolamine catalyst, and the amount of catalyst can be 0.2-3 mol% of the total monomer amount (the sum of the amounts of the imino ionic liquid and the diisocyanate compound).

[0084] In some embodiments, as shown in Formula 2, imine ionic liquids can be prepared by an addition reaction between an amino ionic liquid and a diene compound.

[0085] Among them, the amine ionic liquid can be a commonly used ionic liquid containing an amine group in this field. The amine ionic liquid can be obtained commercially or can be prepared in the laboratory.

[0086] Dienyl compounds can be compounds containing two alkenyl groups commonly used in the art. For example, dienyl compounds can be selected from at least one of poly(ethylene glycol) diacrylate, poly(ethylene glycol) dimethacrylate, polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol diacrylate, ethylene glycol diacrylate, triethylene glycol diacrylate, tetra(ethylene glycol) diacrylate, ethylene glycol dimethacrylate, poly(propylene glycol) dimethacrylate, bis(2-methylpropene)ethoxydisulfide, and diallyl disulfide. The structural formulas of some dienyl compounds are as follows;

[0087] , ,

[0088] A1 A2

[0089] , ,

[0090] A3 A4

[0091] , .

[0092] A5 A6

[0093] In the above structure, n represents the degree of aggregation, which is a positive integer.

[0094] As shown in Formula 2, when an amino ionic liquid reacts with a dienyl compound, the dienyl compound is used to form R2, and the amino ionic liquid is used to form R3, thereby obtaining an imine ionic liquid including R3 and R2.

[0095] Formula 2

[0096] Specifically, compound A1 forms an a1 group, compound A2 can form an a2 group, compound A3 can form an a3 group, compound A4 can form an a4 group, compound A5 can form an a5 group, and compound A6 can form an a6 group.

[0097] This application does not specifically limit the reaction conditions between the amino ionic liquid and the dienyl compound. A moderate excess of the amino ionic liquid is primarily intended to ensure a complete chemical reaction between the dienyl compound and the amino groups. Furthermore, the molar ratio of the amino groups in the amino ionic liquid to the alkenyl groups in the dienyl compound can be (1.0~1.2):1. In some embodiments, a reaction temperature of 40℃-90℃ and a reaction time of 8h~24h during the reaction of the amino ionic liquid and the dienyl compound helps to obtain polymers with excellent overall properties.

[0098] A second aspect of this application provides a polymer electrolyte comprising a lithium salt and the polymer of the first aspect of this application.

[0099] In this process, lithium salts are used to transport lithium ions, and polymers form the backbone of the polymer electrolyte, with the lithium salts embedded within the polymer backbone.

[0100] This application does not specifically limit the lithium salt, and it can be selected from lithium salts commonly used in the art. For example, the lithium salt can be selected from at least one of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(trifluoromethanesulfonyl)imide (LiFSI), lithium tetrafluoroborate (LiBF4), and lithium hexafluorophosphate (LiPF6). Because the polymer electrolyte of this application includes the polymer of the first aspect, when applied to a battery, it can improve the electrochemical performance of the battery and extend its lifespan.

[0101] It is understood that the addition of lithium salt in this application can be done by directly adding the corresponding lithium salt during the preparation of the polymer electrolyte, or by adding the corresponding lithium salt in the form of electrolyte during the battery preparation process.

[0102] In some embodiments, the polymer of the first aspect can be mixed uniformly with lithium salt and solvent, and then the solvent can be removed to form a polymer electrolyte comprising the polymer of the first aspect and lithium salt.

[0103] In other embodiments, the polymer electrolyte is obtained by reacting a feedstock system comprising lithium salts, imine ionic liquids, and diisocyanate compounds.

[0104] Specifically, a raw material system can be obtained by mixing a solvent, a lithium salt, an imine ionic liquid, and a diisocyanate compound. The raw material system is then reacted, and the imine ionic liquid and the diisocyanate compound react to form a polymer including the structure of Formula 1. The electrolyte formed by the lithium salt and the solvent is embedded in the polymer. After drying to remove the solvent, a polymer electrolyte including the lithium salt and the polymer of the first aspect is obtained.

[0105] This application does not impose any particular restrictions on the preparation method of polymer electrolytes, and those skilled in the art are free to choose the manufacturing method appropriate to their purpose.

[0106] In some embodiments, polymer electrolytes can be obtained by self-supporting film formation. For example, the polymer electrolyte raw material system can be applied to a carrier (such as a release film, electrode, or battery casing) to initiate the polymerization of the raw material system to obtain the polymer electrolyte. Alternatively, the polymer system can be cast onto a release film, cured into a film, and then peeled off. Another method is to extrude the polymer system into a film.

[0107] In some embodiments, the polymer electrolyte can be prepared by a method including the following steps:

[0108] The polymer is added to the first solvent to obtain a first mixture; lithium salt is added to the first mixture and stirred until homogeneous to obtain a polymer system; the polymer system is poured onto the surface of a release film, and then the first solvent is removed and separated from the release film to obtain a polymer electrolyte.

[0109] This application does not impose any particular restrictions on the first solvent, which can be selected from commonly used solvents, such as N-methylpyrrolidone (NMP), acetone, methanol, ethanol, etc.

[0110] In some embodiments of this application, when the mass percentage of lithium salt in the polymer electrolyte is 5%-30% and the mass percentage of polymer is 70%-95%, the polymer electrolyte has superior room temperature ionic conductivity and mechanical properties. When applied to batteries, it can further improve the electrochemical performance of the battery and extend the battery's lifespan.

[0111] A third aspect of this application provides a membrane comprising a porous matrix and a polymer electrolyte of the first aspect or the polymer electrolyte of the second aspect disposed in at least a portion of the surface of the porous matrix and / or at least a portion of the pores of the porous matrix.

[0112] It is understood that in the diaphragm of this application, the polymer can be disposed on part or the entire surface of the porous matrix, or in part or the entire pores of the porous matrix; or the polymer electrolyte can be disposed on part or the entire surface of the porous matrix, or in part or the entire pores of the porous matrix.

[0113] This application does not impose specific limitations on the thickness of the porous matrix, but it is preferably 5-50 μm. This application also does not impose specific limitations on the pore size and porosity in the porous matrix, but they are preferably 0.2-100 μm and 10-99%, respectively, and more preferably 0.5-50 μm and 30-70%, respectively.

[0114] This application does not limit the specific setting method. The polymer or polymer electrolyte can be set in at least part of the surface of the porous matrix and / or at least part of the pores of the porous matrix to form a membrane using the setting method commonly used in the art.

[0115] In some embodiments, the separator can be obtained by coating the polymer electrolyte raw material system onto the separator, initiating polymerization of the raw material system, and then curing it. Alternatively, the separator can be obtained by hot-pressing or roll-pressing a self-forming polymer electrolyte with a porous matrix. Another method is to coat the polymer system onto the separator and then cure it. The separator has a porous matrix, which can be any porous matrix commonly used for battery separators. For example, the porous matrix can be a membrane or fabric matrix formed from any of the following polymers, such as polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, polyvinyl naphthalene, polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, tetrafluoropropylene copolymer, hexafluoropropylene copolymer; or at least one of copolymers, homopolymers and derivatives of propylene, 1-butene, pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene.

[0116] In some embodiments, the polymer can be prepared by a method including the following steps: adding a polymer to a first solvent to obtain a first mixture; adding a lithium salt to the first solution and stirring until homogeneous to obtain a polymer system; casting the polymer system onto at least a portion of the surface of a porous matrix, and then removing the first solvent to obtain a membrane.

[0117] This application does not impose any particular restrictions on the first solvent, which can be selected from common solvents, such as N-methylpyrrolidone (NMP), acetone, methanol, ethanol, etc.

[0118] In some embodiments, the preparation method of the diaphragm may further include the following steps: the diaphragm obtained after drying is subjected to roll pressing treatment to make the polymer electrolyte and the porous matrix more tightly bonded.

[0119] The separator of this application, because it includes the aforementioned polymer or polymer electrolyte, can improve the electrochemical performance of the battery and broaden the application scenarios of the battery when applied to it.

[0120] A fourth aspect of this application is a battery comprising the polymer of the first aspect;

[0121] Or, including polymer electrolytes in the second aspect;

[0122] Alternatively, it may include a separator, which is a third party. It is understood that the battery of this application also includes a positive electrode, a negative electrode, and outer packaging.

[0123] In some embodiments, the polymer can be combined with the electrolyte to form a gel electrolyte for use in the battery. That is, a positive electrode, a polymer (or separator), and a negative electrode are stacked to obtain an electrode assembly, which is then placed in an outer package, injected with electrolyte, and sealed to obtain a battery.

[0124] In other embodiments, a positive electrode, a polymer electrolyte (or a separator containing a polymer electrolyte), and a negative electrode can be stacked to obtain an electrode assembly. The electrode assembly is then placed in an outer package and sealed to obtain a battery.

[0125] The battery of this application, due to including the aforementioned polymer electrolyte, exhibits excellent electrochemical performance, provides a superior user experience, and is suitable for widespread application.

[0126] The technical solution of this application will be described in detail below through specific embodiments.

[0127] The sources of some components in the examples and comparative examples are as follows. Components for which specific experimental steps or conditions are not specified in the examples or comparative examples can be obtained by following conventional experimental steps or conditions described in the art.

[0128] (a) Amine ionic liquids:

[0129] (1) 1-Aminoethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt (CAS: 1384979-21-8) and 1-aminopropyl-3-methylimidazolium tetrafluoroborate (CAS: 914770-49-3) were both purchased from Qingdao Aolike New Material Technology Co., Ltd.

[0130] (2) (6-aminohexyl)triphenylphosphonium bromide bis(trifluoromethanesulfonyl)imide salt: It was prepared in the laboratory as follows:

[0131] (6-aminohexyl)triphenylphosphonium bromide hydrobromide (purchased from Sigma-Aldrich) was dissolved in anhydrous ethanol (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) and stirred until fully dissolved. Then, silver bis(trifluoromethanesulfonyl)imide (purchased from Sigma-Aldrich) was gradually added and stirred continuously until silver bromide (AgBr) precipitate was formed. The precipitate was then removed by filtration, and the anhydrous ethanol was removed by vacuum rotary evaporation. After heating and drying, (6-aminohexyl)triphenylphosphonium bromide bis(trifluoromethanesulfonyl)imide salt was obtained.

[0132] (ii) Triethylene glycol diacrylate: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0133] (iii) 4,4'-Diisocyanate dicyclohexylmethane: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0134] (iv) Dibutyltin dilaurate: purchased from Sigma-Aldrich.

[0135] (v) Hexamethylene diisocyanate: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0136] (vi) 1,4-cyclohexanediethanol diethylene ether: purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0137] (vii) m-phenylenedimethyl isocyanate: purchased from Shanghai McLean Biochemical Technology Co., Ltd.

[0138] (viii) Polyethylene glycol diacrylate (Mn=575): purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0139] (ix) Terephthalic diisocyanate: purchased from Shanghai McLean Biochemical Technology Co., Ltd.

[0140] (x) Diallyl disulfide: purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0141] Example 1

[0142] The battery in this embodiment is prepared by a method including the following steps:

[0143] 1) Polymer preparation

[0144] An amino-based ionic liquid is reacted with a diene-based compound to produce an imine-based ionic liquid.

[0145] A second reaction is carried out between an imine-based ionic liquid and a diisocyanate compound to obtain a polymer.

[0146] Among them, the amino ionic liquid is 1-aminoethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, the dienyl compound is triethylene glycol diacrylate, and the diisocyanate compound is 4,4'-diphenylmethane diisocyanate.

[0147] In the first reaction, the molar ratio of amino groups in the amino ionic liquid to the molar ratio of alkenyl groups in the dienyl compound was 1:1, the temperature was 60℃, and the time was 12h.

[0148] In the second reaction, the molar ratio of imine groups in the imine ionic liquid to isocyanate groups in the diisocyanate compound is 1:1, the temperature is 60℃, the time is 12h, the catalyst is dibutyltin dilaurate, and the amount of catalyst used is 0.2 mol of the sum of the amounts of imine ionic liquid and diisocyanate compound.

[0149] 2) Preparation of polymer electrolytes

[0150] The solvent, lithium salt, and polymer from step 1) are mixed and then dried to obtain a polymer electrolyte.

[0151] The lithium salt is lithium hexafluorophosphate, and the solvent is NMP.

[0152] In the polymer electrolyte, the mass percentage of lithium salt is 10%, and the mass percentage of polymer is 90%.

[0153] 3) Battery manufacturing

[0154] An electrolytic assembly is obtained by stacking positive electrode, polymer electrolyte and negative electrode, and the electrode assembly is placed in an aluminum-plastic film and sealed to obtain a battery;

[0155] The positive electrode sheet includes an aluminum foil and a positive electrode active layer disposed on the surface of the aluminum foil. The positive electrode active layer includes lithium cobalt oxide, conductive agent Super P, and binder PVDF. The mass ratio of lithium cobalt oxide, conductive agent, and binder is 96:2:2.

[0156] The negative electrode sheet includes a copper foil and a negative electrode active layer disposed on the surface of the copper foil. The negative electrode active layer includes silicon-doped graphite, conductive agent Super P, and binder PAA. The mass ratio of silicon-doped graphite, conductive agent, and binder is 95:2:3.

[0157] Example 2

[0158] The battery preparation method in this embodiment is basically the same as that in Embodiment 1, except that...

[0159] 1) Polymer preparation

[0160] The diisocyanate compound is hexamethylene diisocyanate.

[0161] Example 3

[0162] The battery preparation method in this embodiment is basically the same as that in Embodiment 1, except that...

[0163] 1) Polymer preparation

[0164] The amine ionic liquid is 1-aminopropyl-3-methylimidazolium tetrafluoroborate, the dienyl compound is 1,4-cyclohexanediethanol divinyl ether, and the diisocyanate compound is isophthalic diisocyanate.

[0165] Example 4

[0166] The battery preparation method in this embodiment is basically the same as that in Embodiment 1, except that...

[0167] 1) Polymer preparation

[0168] The amine ionic liquid is 1-aminopropyl-3-methylimidazolium tetrafluoroborate, the dienyl compound is polyethylene glycol diacrylate (Mn=575), and the diisocyanate compound is terephthalic diisocyanate.

[0169] Example 5

[0170] The battery preparation method in this embodiment is basically the same as that in Embodiment 1, except that...

[0171] 1) Polymer preparation

[0172] The amine ionic liquid is 1-aminopropyl-3-methylimidazolium tetrafluoroborate, the dienyl compound is diallyl disulfide, and the diisocyanate compound is terephthalic diisocyanate.

[0173] Example 6

[0174] The battery preparation method in this embodiment is basically the same as that in Embodiment 1, except that...

[0175] 1) Polymer preparation

[0176] The amine ionic liquid is (6-aminohexyl)triphenylphosphonium bromide bis(trifluoromethanesulfonyl)imide salt, the diene compound is polyethylene glycol diacrylate (Mn=575), and the diisocyanate compound is terephthalic diisocyanate.

[0177] In the first reaction, the molar ratio of the amino group content in the amino ionic liquid to the molar ratio of the alkenyl group content in the dienyl compound is 1.2:1;

[0178] In the second reaction, the molar ratio of imine groups in the imine ionic liquid to the molar ratio of isocyanate groups in the diisocyanate compound is 1:1.2.

[0179] Example 7

[0180] The battery preparation method in this embodiment is basically the same as that in Embodiment 1, except that:

[0181] Polymer electrolytes are prepared by a method comprising the following steps:

[0182] An amino-based ionic liquid is reacted with a diene-based compound to produce an imine-based ionic liquid.

[0183] A second reaction is carried out with an imine-based ionic liquid, a diisocyanate compound, a lithium salt, and a solvent, followed by drying to obtain a polymer electrolyte.

[0184] Among them, the amino ionic liquid is 1-aminoethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, the dienyl compound is triethylene glycol diacrylate, and the diisocyanate compound is 4,4'-diisocyanate dicyclohexylmethane.

[0185] In the first reaction, the molar ratio of amino groups in the amino ionic liquid to the molar ratio of alkenyl groups in the dienyl compound was 1:1, the temperature was 60℃, and the time was 12h.

[0186] In the second reaction, the molar ratio of imine groups in the imine ionic liquid to isocyanate groups in the diisocyanate compound was 1:1, the temperature was 60℃, the time was 12 h, the catalyst was dibutyltin dilaurate, and the amount of catalyst used was 0.2 mol% of the sum of the amounts of the imine ionic liquid and the diisocyanate compound.

[0187] The lithium salt is lithium hexafluorophosphate, and the solvent is NMP;

[0188] In the polymer electrolyte, the mass percentage of lithium salt is 10%, and the mass percentage of polymer is 90%.

[0189] Example 8

[0190] The battery preparation method in this embodiment is basically the same as that in Embodiment 1, except that:

[0191] 2) Preparation of polymer electrolytes

[0192] In the polymer electrolyte, the mass percentage of lithium salt is 40%, and the mass percentage of polymer is 60%.

[0193] Example 9

[0194] The battery preparation method in this embodiment is basically the same as that in Embodiment 1, except that:

[0195] 2) Polymer preparation

[0196] The amine ionic liquids include 1-aminoethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1-aminopropyl-3-methylimidazolium tetrafluoroborate, and (6-aminohexyl)triphenylphosphonium bromide bis(trifluoromethanesulfonyl)imide salt, wherein the molar ratio of 1-aminoethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1-aminopropyl-3-methylimidazolium tetrafluoroborate, and (6-aminohexyl)triphenylphosphonium bromide bis(trifluoromethanesulfonyl)imide salt is 1:1:1.

[0197] Example 10

[0198] The battery preparation method in this embodiment is basically the same as that in Embodiment 1, except that:

[0199] 2) Polymer preparation

[0200] The dienyl compounds include triethylene glycol diacrylate, 1,4-cyclohexanediethanol diethylene ether, and polyethylene glycol diacrylate (Mn=575), wherein the molar ratio of triethylene glycol diacrylate, 1,4-cyclohexanediethanol diethylene ether, and polyethylene glycol diacrylate is 1:1:1.

[0201] Example 11

[0202] The battery preparation method in this embodiment is basically the same as that in Embodiment 1, except that:

[0203] 2) Polymer preparation

[0204] Diisocyanate compounds include terephthalic diisocyanate and isophthalic diisocyanate, wherein the molar ratio of terephthalic diisocyanate to isophthalic diisocyanate is 1:1.

[0205] Comparative Example 1

[0206] The preparation method of the battery in this comparative example is basically the same as that in Example 1, except that...

[0207] Polymer electrolytes are prepared by a method comprising the following steps:

[0208] Polyetheramine D230, hexamethylene diisocyanate, lithium salt and solvent were mixed and reacted at 60°C for 12 hours. The solvent was then removed by drying to obtain the polymer electrolyte.

[0209] In the above reaction, the molar ratio of the amino group content of polyetheramine D230 to the molar ratio of the isocyanate group content of hexamethylene diisocyanate is 1.1:1.

[0210] Comparative Example 2

[0211] The preparation method of the battery in this comparative example is basically the same as that in Example 1, except that...

[0212] Polymer electrolytes are prepared by a method comprising the following steps:

[0213] 1-Aminoethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 4,4'-diisocyanate dicyclohexylmethane, lithium salt and solvent were mixed and reacted at 60°C for 12 h. The solvent was then removed by drying to obtain the polymer electrolyte.

[0214] In the above reaction, the molar ratio of the amino group of 1-aminoethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine salt to the molar ratio of the isocyanate group of hexamethylene diisocyanate is 1:2. The catalyst is dibutyltin dilaurate, and the amount of catalyst used is 0.2 mol of the sum of the amounts of the imine ionic liquid and the diisocyanate compound.

[0215] Comparative Example 3

[0216] The preparation method of the battery in this comparative example is basically the same as that in Example 1, except that...

[0217] Polymer electrolytes are prepared by a method comprising the following steps:

[0218] 1-Aminoethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, triethylene glycol diacrylate, lithium salt and solvent were mixed and reacted at 60°C for 12 hours. The solvent was then removed by drying to obtain the polymer electrolyte.

[0219] In the above reaction, the molar ratio of the amino group of 1-aminoethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imine salt to the molar ratio of the vinyl group of triethylene glycol diacrylate is 1:2. The catalyst is dibutyltin dilaurate, and the amount of catalyst used is 0.2 mol of the sum of the amounts of the imine ionic liquid and the diisocyanate compound.

[0220] Comparative Example 4

[0221] The preparation method of the battery in this comparative example is basically the same as that in Example 1, except that...

[0222] 1) Polymer preparation

[0223] An amino ionic liquid, a dienyl compound, and a diisocyanate compound are added to a reaction vessel to carry out the first reaction (the amino ionic liquid and the diisocyanate compound react preferentially to form a urea intermediate compound).

[0224] After the addition of a catalyst, the alkenyl group of the dienyl compound undergoes a second reaction with the imine group of the urea intermediate to obtain a polymer;

[0225] In the first reaction, the ratio of the molar content of amino groups in the amino ionic liquid, the molar content of alkenyl groups in the dienyl compound, and the molar content of isocyanate groups in the diisocyanate compound is 1:1:1, the temperature is 60℃, and the time is 2h.

[0226] In the second reaction, the catalyst was dibutyltin dilaurate, and the amount of catalyst was 0.2 mol% of the sum of the amounts of the amine ionic liquid, dienyl compound, and diisocyanate compound. The temperature was 60℃ and the time was 12 h.

[0227] Performance testing

[0228] The polymers, polymer electrolytes, or batteries in the examples and comparative examples were subjected to the following performance tests, and the test results are shown in Table 1.

[0229] 1. Infrared testing

[0230] Infrared testing was performed on the polymer in Example 1, from... Figure 1 As can be seen from the infrared spectrum of the polymer in Example 1, 3308 cm⁻¹ -1 and 1642cm -1 The absorption peaks at 1228 cm⁻¹ originate from the vibrational absorption of the NH and C=O bonds in the urea group, respectively; -1 The absorption peak at 1373 cm⁻¹ is the absorption peak of the stretching vibration of the CN bond. -1 The absorption peak at 1453 cm⁻¹ originates from the vibrational absorption of the tertiary amine, indicating the presence of a tertiary amine group in the polymer structure; -1 1506 cm -1 and 1594 cm -1 The absorption peak at 1537 cm⁻¹ originates from the stretching vibration absorption of the benzene ring; -1 The absorption peak at 1178 cm⁻¹ is due to the skeletal vibration absorption of the imidazole ring. -1 The absorption peak at 2860–2930 cm⁻¹ originates from the stretching vibration absorption of the imidazole ring. -1 The absorption peak is for the stretching vibrations of methyl and methylene groups; 1102 cm⁻¹ -1 The absorption peak at that location originates from the stretching vibration absorption of the ether bonds in the polymer structure. This demonstrates that Example 1 of this application successfully prepared a polymer comprising the structure shown in Formula 1.

[0231] 2. Room temperature ionic conductivity

[0232] The test was conducted using the method specified in the "Test Method for Ionic Conductivity of Power Battery Thin Films" (Industry Standard NB / T 10827-2021).

[0233] 3. Battery cycle performance

[0234] The tests were conducted according to the methods specified in the national standard GB / T31486-2015 "Electrical Performance Requirements and Test Methods for Power Batteries for Electric Vehicles".

[0235] 4. Limiting Oxygen Index

[0236] The tests were conducted according to the methods specified in GB / T2406.1-2008 "Determination of flammability of plastics by oxygen index method - Part 1: Guidelines" and GB / T2406.2-2009 "Determination of flammability of plastics by oxygen index method - Part 2: Room temperature test".

[0237] 5. Tensile strength test

[0238] The tensile strength of the polymer electrolyte is measured according to the standard test method of ASTM D638-14, "Standard Test Method for Tensile Properties of Plastics".

[0239] Table 1

[0240]

[0241] As shown in Table 1, the product of this application embodiment has excellent room temperature ionic conductivity, battery capacity retention rate and limiting oxygen index, and its performance is excellent and can be widely used.

[0242] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A polymer, wherein, The polymer includes at least the structural formula shown in Formula 1; In Formula 1, R1 is selected from substituted or unsubstituted C1-C30 alkyl groups and substituted or unsubstituted C6-C60 aryl groups; R2 is selected from substituted or unsubstituted polyether groups, substituted or unsubstituted C1-C30 alkyl groups, substituted or unsubstituted C1-C30 alkoxy groups, and *-b1-SS-b2-*; b1 and b2 are each independently selected from substituted or unsubstituted C2-C15 chain alkyl groups and substituted or unsubstituted C6-C60 aryl groups. R3 is an ionic liquid group; n≥1 and is an integer.

2. The polymer according to claim 1, wherein, When the polymer includes multiple structures of Formula 1, R3 is selected from the same ionic liquid group.

3. The polymer according to claim 1, wherein, When the polymer includes multiple structural formulas of Formula 1, at least one of the following conditions must be met: a) The R1 in multiple structural formulas of Formula 1 is selected from the same group; b) The R2 in multiple of the structural formulas of Formula 1 is selected from the same group.

4. The polymer according to claim 1, wherein, R3 is selected from one of the following: imidazole ionic liquid groups, pyridine ionic liquid groups, quaternary ammonium ionic liquid groups, or quaternary phosphonium ionic liquid groups.

5. The polymer according to claim 4, wherein, The R3 is selected from any one of the following groups; Wherein, R4 is selected from substituted or unsubstituted C1-C30 alkyl groups and substituted or unsubstituted C1-C30 alkoxy groups; R5 is selected from substituted or unsubstituted C1-C10 alkyl groups; A is selected from BF4. - PF6 - TFSI - OTf - DCA - or TOS - .

6. The polymer according to any one of claims 1-5, wherein, The R2 is selected from any one of the following groups; Where n is a positive integer.

7. The polymer according to any one of claims 1-6, wherein, At least one of the following must be met: a) R1 is a ring structure; b) The R2 is a chain-like structure.

8. The polymer according to any one of claims 1-7, wherein, The polymer is obtained by reacting an imine-based ionic liquid with a diisocyanate compound.

9. A polymer electrolyte, wherein, The polymer electrolyte includes lithium salts and the polymers described in any one of claims 1-8.

10. The polymer electrolyte according to claim 9, wherein, In the polymer electrolyte, the lithium salt has a mass percentage content of 5-30%, and the polymer has a mass percentage content of 70-95%.

11. A diaphragm, wherein, It includes a porous matrix, and a polymer of any one of claims 1-8 or a polymer electrolyte of any one of claims 9-10 disposed in at least a portion of the surface of the porous matrix and / or at least a portion of the pores of the porous matrix.

12. A battery, wherein, Includes the polymer according to any one of claims 1-8; Or, including the polymer electrolyte according to any one of claims 9-10; Or, including the diaphragm as described in claim 11.

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