Polymer and application thereof

Abstract

The invention provides a polymer and application thereof. The polymer comprises a first block as shown in a formula 1 and a second block as shown in a formula 2, r1 is selected from a substituted or unsubstituted alkyl group of C1 to C30, a substituted or unsubstituted polyether group, a substituted or unsubstituted alkoxy group of C1 to C30, and a substituted or unsubstituted aryl group of C6 to C60; r2 is selected from a substituted or unsubstituted polyether group, a substituted or unsubstituted alkyl group of C1 to C30, a substituted or unsubstituted alkoxy group of C1 to C30, a substituted or unsubstituted aryl group of C6 to C60, and *-b1-S-S-b2-*; b1 and b2 are respectively and independently selected from a substituted or unsubstituted C2-C15 chain alkyl group or a substituted or unsubstituted C6-C60 aryl group; and R3 is an ionic liquid-containing group. Due to the special molecular structure of the polymer, the polymer has excellent electrochemical performance and mechanical strength when being applied to the composite electrolyte.

Description

A polymer and its application Technical Field

[0001] The embodiments of the present application relate to a polymer and its application, belonging to the field of energy technology. Background Art

[0002] Inorganic solid electrolytes possess excellent ionic conductivity, high energy density, high mechanical strength, and high safety, and are considered to have broad market potential for battery applications. However, inorganic solid electrolytes have drawbacks such as high material brittleness and poor flexibility, complex preparation processes, and extremely poor interfacial contact between the inorganic solid electrolyte and the battery's electrodes, resulting in high internal resistance in solid-state batteries.

[0003] To overcome the shortcomings of inorganic solid electrolytes, existing technologies prepare organic-inorganic solid composite electrolytes by introducing polymer electrolytes into inorganic solid electrolytes. Because polymers have excellent flexibility and processing properties, the resulting organic-inorganic solid composite electrolytes have relatively excellent flexibility and processing properties. However, polymer electrolytes have problems such as low mechanical strength, poor room temperature ionic conductivity, and low ion transference numbers, which can easily affect the mechanical and electrochemical properties of organic-inorganic solid composite electrolytes. In addition, organic-inorganic solid composite electrolytes are prone to poor interfacial compatibility between polymer electrolytes and inorganic solid electrolytes, which affects the overall performance of organic-inorganic solid composite electrolytes.

[0004] Summary of the Invention

[0005] The present application provides a polymer whose special molecular structure enables it to have excellent electrochemical properties and mechanical strength when used in composite electrolytes.

[0006] The present application provides a composite electrolyte with excellent electrochemical properties and mechanical strength, which can be widely used in batteries to improve the overall performance of the batteries.

[0007] The present application provides a diaphragm, which includes the above-mentioned polymer or composite electrolyte, so when applied to a battery, the overall performance of the battery can be improved.

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

[0009] The present application provides a polymer, wherein the polymer comprises a first block represented by Formula 1 and a second block represented by Formula 2;

[0010] Wherein, R1 is selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted polyether group, substituted or unsubstituted C1-C30 alkoxy group, substituted or unsubstituted C6-C60 aryl group;

[0011] R2 is selected from substituted or unsubstituted polyether groups, substituted or unsubstituted C1-C30 alkyl groups, substituted or unsubstituted C1-C30 alkoxy groups, substituted or unsubstituted C6-C60 aryl groups, *-b1-SS-b2-*; b1 and b2 are each independently selected from substituted or unsubstituted C2-C15 chain alkyl groups or substituted or unsubstituted C6-C60 aryl groups;

[0012] R3 is an ionic liquid-containing group;

[0013] m≥1, n≥1, and both are integers.

[0014] The polymer as described above, wherein, when the polymer includes a plurality of first blocks of Formula 1, at least one of the following is satisfied:

[0015] a) R3 in a plurality of the first blocks is selected from the same ionic liquid group;

[0016] b) R1 in a plurality of the first blocks is selected from the same group.

[0017] The polymer as described above, wherein when the polymer includes a plurality of second blocks of Formula 2, R1 in the plurality of second blocks is selected from the same group and R2 in the plurality of second blocks is selected from the same group.

[0018] In the polymer as described above, R3 is selected from one of an imidazole ionic liquid group, a pyridine ionic liquid group, a quaternary ammonium ionic liquid group or a quaternary phosphonium ionic liquid group.

[0019] The polymer as described above, wherein R3 is selected from any one of the following groups;

[0020] Wherein, R4 is selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 alkoxy; R5 is selected from substituted or unsubstituted C1-C10 alkyl; A is selected from BF4 - PF6 - TFSI - ,OTf - 、DCA - or TOS - .

[0021] The polymer as described above, wherein at least one of the following is satisfied:

[0022] a) R1 in the first block is a chain structure;

[0023] b) R2 in the second block comprises a cyclic structure.

[0024] The polymer as described above, wherein

[0025] The polymer is prepared by a method comprising the following steps:

[0026] Performing a first reaction between the amino ionic liquid and the diisocyanate compound to obtain a first intermediate compound;

[0027] The first intermediate compound is subjected to a second reaction with a diamine compound and a diisocyanate compound to obtain the polymer.

[0028] The present application provides a composite electrolyte, wherein the composite electrolyte includes an inorganic solid electrolyte and the polymer as described above.

[0029] The composite electrolyte as described above, wherein the mass percentage of the polymer is 10-30% based on the total mass of the composite electrolyte.

[0030] The composite electrolyte as described above further comprises a lithium salt, and the mass percentage of the lithium salt is 1 to 10% based on the total mass of the composite electrolyte.

[0031] The composite electrolyte as described above, wherein it further comprises plastic crystals, and the mass percentage of the plastic crystals is 1 to 10% based on the total mass of the composite electrolyte.

[0032] The present application provides a membrane, which includes a porous matrix, and the polymer or the composite electrolyte described above disposed on at least a portion of the surface of the porous matrix and / or in at least a portion of the pores of the porous matrix.

[0033] The present application provides a battery, comprising the polymer as described above;

[0034] or, comprising a composite electrolyte as described above;

[0035] Or, comprising a membrane as described above.

[0036] The polymer of the present application includes the structural formulas shown in Formula 1 and Formula 2. When the polymer is applied to a composite electrolyte (including an inorganic solid electrolyte and a polymer electrolyte), it can improve the electrochemical and mechanical properties of the composite electrolyte.

[0037] The composite electrolyte of the present application includes the polymer with the above-mentioned special molecular structure. The composite electrolyte has excellent electrochemical properties and mechanical strength and can be widely used in batteries to improve the electrochemical performance of the battery and extend the service life of the battery.

[0038] The separator of the present application includes the above-mentioned polymer or composite electrolyte, so when applied to a battery, it can improve the electrochemical performance of the battery and extend the service life of the battery.

[0039] The battery of the present application, because it includes any one of the above-mentioned polymer, composite electrolyte and separator, has excellent electrochemical performance and a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIG1 is an infrared test curve diagram of the polymer in Example 2 of the present application. DETAILED DESCRIPTION

[0041] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0042] A first aspect of the present application provides a polymer, comprising a first block represented by Formula 1 and a second block represented by Formula 2;

[0043] Wherein, R1 is selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted polyether group, substituted or unsubstituted C1-C30 alkoxy group, substituted or unsubstituted C6-C60 aryl group;

[0044] R2 is selected from substituted or unsubstituted polyether groups, substituted or unsubstituted C1-C30 alkyl groups, substituted or unsubstituted C1-C30 alkoxy groups, substituted or unsubstituted C6-C60 aryl groups, *-b1-SS-b2-*; b1 and b2 are each independently selected from substituted or unsubstituted C2-C15 chain alkyl groups or substituted or unsubstituted C6-C60 aryl groups;

[0045] R3 is an ionic liquid-containing group;

[0046] m≥1, n≥1.

[0047] The polymer of the present application includes a first block as shown in Formula 1 and a second block as shown in Formula 2. The present application does not limit the number of first blocks and the number of second blocks in the polymer. The number of first blocks and the number of second blocks may be the same or different. The present application also does not limit the arrangement of the first block and the second block. The first block and the second block may be arranged in sequence (for example, the structural formula of the polymer includes the first block, the first block, the second block, and the second block connected in sequence); the first block and the second block may be arranged alternately (for example, the structural formula of the polymer includes the first block, the second block, the first block, and the second block connected in sequence); the first block and the second block may also be arranged irregularly (for example, the structure of the polymer includes the first block, the second block, the first block, the first block, and the second block connected in sequence).

[0048] Specifically, R1 is selected from a substituted or unsubstituted polyether group (for example, a substituted chain polyether group, an unsubstituted chain polyether group, a substituted cyclic polyether group, or an unsubstituted cyclic polyether group), a substituted or unsubstituted C1-C30 alkyl group (for example, an unsubstituted linear alkyl group, an unsubstituted branched alkyl group, an unsubstituted cycloalkyl group, a substituted linear alkyl group, a substituted branched alkyl group, or a substituted cycloalkyl group), a substituted or unsubstituted C1-C30 alkoxy group (for example, a substituted chain alkoxy group, an unsubstituted chain alkoxy group, a substituted cyclic alkoxy group, or an unsubstituted cyclic alkoxy group), a substituted or unsubstituted C6-C60 aryl group (for example, a substituted phenyl group, a substituted biphenyl group, an unsubstituted phenyl group, or an unsubstituted biphenyl group);

[0049] R2 is selected from a substituted or unsubstituted C1-C30 alkyl group (for example, an unsubstituted linear alkyl group, an unsubstituted branched alkyl group, an unsubstituted cycloalkyl group, a substituted linear alkyl group, a substituted branched alkyl group, or a substituted cycloalkyl group), a substituted or unsubstituted C1-C30 alkoxy group (for example, a substituted branched alkoxy group, a substituted linear alkoxy group, a substituted cyclic alkoxy group, an unsubstituted linear alkoxy group, an unsubstituted branched alkoxy group, or an unsubstituted cyclic alkoxy group), a substituted or unsubstituted polyether group (for example, a substituted chain polyether group, an unsubstituted chain polyether group, a substituted cyclic polyether group, or an unsubstituted cyclic polyether group), a substituted or unsubstituted C6-C60 aryl group (for example, a substituted phenyl group, a substituted biphenyl group, an unsubstituted phenyl group, or an unsubstituted biphenyl group), *-b1-SS-b2-* (b1 and b2 are each independently selected from a substituted or unsubstituted C2-C15 chain alkyl group or a substituted or unsubstituted aryl group, and * represents the position of connection to the main chain in Formula 1 (or Formula 2));

[0050] The present application does not particularly limit the substituents in R1 and R2, and the substituents may be substituents commonly used in the art. For example, the substituents may 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, halogen groups, and amino groups.

[0051] The ionic liquid group in R3 refers to an organic group containing a cation and an anion.

[0052] m and n are positive integers. The polymer of the present application can be used for compounding with an inorganic solid electrolyte to prepare a composite electrolyte including a polymer electrolyte and an inorganic solid electrolyte. The ionic liquid group in the polymer of the present application has good ionic conductivity, and can realize rapid transmission of ions in the composite electrolyte; and the urea group (-NH-CO-NH-) in the polymer has a strong polar effect, which can cause a strong physical interaction between the polymer electrolyte and the inorganic solid electrolyte, so that the inorganic solid electrolyte and the polymer electrolyte can be tightly combined, and the interface compatibility between the inorganic solid electrolyte and the polymer electrolyte is improved; at the same time, since the polymer of the present application includes a first block containing an ionic liquid group and a second block containing a urea group, it is a polymer of a block-like structure, wherein the first block containing an ionic liquid group can make the transmission efficiency of lithium ions in the polymer electrolyte higher, and there is an excellent interface interaction between the second block containing a urea group and the inorganic solid electrolyte, which can reduce the internal interface impedance of the composite electrolyte, improve the transmission of lithium ions between the composite electrolyte, and then improve the electrochemical performance of the composite electrolyte.

[0053] Furthermore, the urea groups in the polymer form strong hydrogen bonds, resulting in a large dynamic hydrogen bond network within the composite electrolyte. This dynamic hydrogen bond network continuously expands and forms during deformation, dissipating the energy generated by material deformation and imparting excellent mechanical flexibility to the composite electrolyte. Furthermore, the ionic liquid groups in the polymer exhibit excellent flame retardancy, significantly enhancing the flame retardancy of the composite electrolyte and, in turn, improving battery safety.

[0054] It can be understood that in the polymer of the present application, R1 in the first block and R1 in the second block may be the same or different; and when the polymer includes multiple first blocks (m≥2), R1 in the multiple first blocks may be the same or different, and R3 in the multiple first blocks may be the same or different; when the polymer includes multiple second blocks (n≥2), R1 in the multiple second blocks may be the same or different, and R2 in the multiple second blocks may be the same or different.

[0055] In some embodiments of the present application, when the polymer includes multiple first blocks represented by Formula 1 (m≥2), R3 in the multiple first blocks is selected from the same ionic liquid group. The same ionic liquid group is beneficial to improving the uniformity of ion conduction, so that the polymer has higher ionic conductivity.

[0056] In some embodiments of the present application, when the polymer includes multiple first blocks represented by Formula 1 (m≥2), R1 in the multiple first blocks is selected from the same group. The same group is beneficial to improving the regularity of the polymer, thereby further improving the uniformity and stability of ion conduction.

[0057] In some embodiments of the present application, when the polymer includes multiple second blocks represented by Formula 2 (n≥2), R1 in the multiple second blocks is selected from the same group and R2 is selected from the same group. The same group is beneficial to improving the uniformity of the second block structure, thereby helping to improve the uniform distribution of interaction sites between polymer molecular chains and improve the physical properties of the polymer.

[0058] In some embodiments of the present application, R3 is selected from one of an imidazole ionic liquid group, a pyridine ionic liquid group, a quaternary ammonium ionic liquid group or a quaternary phosphonium ionic liquid group.

[0059] In the present application, the polymer including the above-mentioned ionic liquid group can have more excellent room temperature ionic conductivity and flame retardant properties when used in a composite electrolyte, and the ionic liquid used to form the above-mentioned ionic liquid group is easy to obtain and relatively low in price, which helps to save production costs.

[0060] Further, R3 is selected from any one of the following groups;

[0061] Wherein, R4 is selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 alkoxy; R5 is selected from substituted or unsubstituted C1-C10 alkyl; A is selected from BF4 - PF6 - TFSI - ,OTf - 、DCA - or TOS - .

[0062] Specifically, * in the above structural formula refers to the position connected to the main chain shown in Formula 1.

[0063] R4 is selected from substituted or unsubstituted C1-C30 alkyl (for example, it can be substituted straight-chain alkyl, substituted branched-chain alkyl, substituted cycloalkyl, unsubstituted branched-chain alkyl, unsubstituted straight-chain alkyl or unsubstituted cycloalkyl), substituted or unsubstituted C1-C30 alkoxy (for example, it can be substituted straight-chain alkoxy, substituted cycloalkoxy, substituted branched-chain alkoxy, unsubstituted cycloalkoxy, unsubstituted straight-chain alkoxy, unsubstituted branched-chain alkoxy); R5 is selected from substituted or unsubstituted C1-C10 alkyl (for example, it can be substituted straight-chain alkyl, substituted branched-chain alkyl, substituted cycloalkyl, unsubstituted branched-chain alkyl, unsubstituted straight-chain alkyl or unsubstituted cycloalkyl).

[0064] Among them, the formation of anionic groups can be obtained by dissociation of corresponding salts. For example, tetrafluoroborate ions are obtained by dissociation of lithium tetrafluoroborate, and hexafluorophosphate ions are obtained by dissociation of lithium hexafluorophosphate. The structures of the anionic groups of the present application are shown below:

[0065] The present application does not particularly limit the substituents in R4 and R5, and the substituents may be substituents commonly used in the art. For example, the substituents may be selected from at least one of a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C2-C30 alkenyl group, a substituted or unsubstituted C3-30 alkynyl group, an ester group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C6-C60 aryl group, and a halogen.

[0066] When R3 is selected from the above structural formula, the production cost can be reduced while further improving the electrochemical performance and flame retardant performance of the battery.

[0067] In some embodiments of the present application, R1 in the first block is a chain structure, that is, R1 in the first block is selected from a substituted or unsubstituted chain polyether group, a substituted or unsubstituted chain C1-C30 alkyl group, or a substituted or unsubstituted chain C1-C30 alkoxy group.

[0068] When R1 in the first block is a chain structure, the transport performance of lithium ions between ionic liquid structures can be regulated, thereby improving the lithium ion transport efficiency of the composite electrolyte.

[0069] In some embodiments of the present application, R2 in the second block comprises a cyclic structure. That is, R2 in the second block is selected from a substituted or unsubstituted cyclic polyether group, a substituted or unsubstituted C6-C60 aryl group, *-b1-SS-b2-* (b1 and b2 are each independently selected from a substituted or unsubstituted C6-C60 aryl group), a substituted or unsubstituted cyclic C3-C30 alkyl group, or a substituted or unsubstituted cyclic C3-C30 alkoxy group.

[0070] When R2 in the second block includes 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 composite electrolyte and extending the service life of the battery.

[0071] In particular, when R1 in the first block of the polymer is a chain structure and R2 in the second block includes a ring structure, the structure of the polymer is both rigid and flexible, which is not only beneficial to improving the physical properties of the second block, but also can increase the flexibility of the molecular chain structure of the second block, so that the molecular chain morphology is adjusted when it interacts with the inorganic solid electrolyte, which is beneficial to increase the interaction sites between the second block and the inorganic solid electrolyte particles, thereby improving the interface bonding performance between the polymer and the inorganic solid electrolyte, and is beneficial to reducing the internal interface impedance of the composite solid electrolyte, so that the polymer electrolyte has both excellent mechanical properties and lithium ion transmission properties, thereby improving the electrochemical performance of the battery and extending the battery life.

[0072] The present application does not impose any particular restrictions on the raw materials and production methods for the polymers. As long as the polymers meet the above-mentioned characteristics, the raw materials and production methods can be freely selected according to the purpose.

[0073] In some embodiments of the present application, the polymer is prepared by a method comprising the following steps:

[0074] Performing a first reaction between the amino ionic liquid and the diisocyanate compound to obtain a first intermediate compound;

[0075] The first intermediate compound is subjected to a second reaction with a diamine compound and a diisocyanate compound to obtain a polymer.

[0076] Specifically, the preparation method of the polymer includes: conducting a first reaction between an amino ionic liquid and a diisocyanate compound, wherein in the first reaction, the amino group in the amino ionic liquid reacts with the isocyanate group in the diisocyanate compound to form a first intermediate compound including a first block, wherein the R3 group in the first block comes from the amino ionic liquid, and the R1 group in the first block comes from the diisocyanate compound;

[0077] The first intermediate compound is subjected to a second reaction with a diamine compound and a diisocyanate compound. In the second reaction, the amino group in the diamine compound reacts with the isocyanate group in the diisocyanate compound to form a second block including a urea group. The second block is interconnected with the first intermediate compound to form a polymer including the first block and the second block. The R1 group in the second block comes from the diisocyanate compound, and the R2 group in the second block comes from the diamine compound.

[0078] The present application does not particularly limit the amino ionic liquid, which may be an amino ionic liquid commonly used in the art. The amino ionic liquid may be purchased commercially or prepared in a laboratory.

[0079] The present application does not particularly limit the diisocyanate compound. The diisocyanate compound can be a compound containing two isocyanate groups commonly used in the art. For example, the diisocyanate compound can be selected from at least one of polyethylene glycol diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane 4,4′-diisocyanate, p-phenylene diisocyanate, 1,4-diisocyanate butane, 1,3-diisophenylcyanate, 1,12-diisocyanatotridecane, toluene diisocyanate-polypropylene glycol copolymer, 1,6-diisocyanato-2,2,4-trimethylhexane, 2,6-diisocyanatotoluene, 6-(4-isocyanatophenoxy)-hexanoic acid 2-[6-(4-isocyanatophenoxy)-hexanoyloxy]-ethyl ester, m-phenylenediisocyanate, toluene-2,4-diisocyanate and 4,4′-diisocyanate dicyclohexylmethane.

[0080] The present application does not particularly limit the diamine compound, which can be a compound containing two amino groups. For example, the diamine compound can be selected from at least one of polyetheramine, cystamine, di(3-aminopropyl)disulfide, 4,4′-diaminodicyclohexylmethane, hexamethylenediamine, 4,7,10-trioxy-1,13-tridecanediamine, 4,4′-diaminodiphenylmethane, p-phenylenediamine, polyethylene glycol diamine, 4,9-dioxa-1,12-dodecanediamine, 4,4′-diaminodiphenyl disulfide, di(6-aminohexyl)disulfide and O,O′-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol.

[0081] The present application does not limit the order of adding the raw materials in the second reaction. The first intermediate compound, the diamine compound and the diisocyanate compound can be mixed before the second reaction occurs; the diamine compound and the diisocyanate compound can be mixed first and then added to the first intermediate compound to cause the second reaction; the first intermediate compound can also be mixed first with the diamine compound and then reacted with the diisocyanate compound to cause the second reaction.

[0082] The present application does not particularly limit the specific parameters of the first reaction, as long as the amino group in the amino ionic liquid can react with the isocyanate group in the diisocyanate compound. In some embodiments, in the first reaction, the temperature is 0-10°C and the time is 5-180 minutes.

[0083] The present application does not particularly limit the specific parameters of the second reaction, as long as the amino group in the diamine compound can react with the isocyanate group of the diisocyanate compound to connect the second block and the first block. In some embodiments, in the second reaction, the temperature is 0-10°C and the time is 5-300 min.

[0084] In some embodiments, the polymer can be prepared by a method comprising the following steps: reacting an amino ionic liquid with a diisocyanate compound at 0-10°C for 5-180 minutes to obtain a first intermediate compound; then gradually adding a diamine compound, and then gradually adding a diisocyanate compound, and reacting at 0-10°C for 5-300 minutes.

[0085] The application does not particularly limit the amount of each raw material added, and can be selected according to actual needs. In some embodiments, in the first reaction, an excess of diisocyanate compounds can enable the amino group in the amino ionic liquid to undergo a complete chemical reaction, thereby forming a first block structure, and an excess of diisocyanate compounds can obtain a first intermediate compound containing reactive isocyanate groups at both ends, so that the first intermediate compound can directly undergo the second reaction; in the second reaction, by adjusting the molar ratio of the first intermediate compound, the diamine compound, and the diisocyanate compound, the molar content of the isocyanate group is close to the molar content of the amino group, the molecular weight distribution change of the polymer can be better controlled, and the degree of polymerization of the polymer is avoided to be greatly affected by the excess of isocyanate groups or the amino group, so that the molecular weight distribution of the polymer changes too much, thereby affecting the physical and chemical properties of the polyurea polymer.

[0086] Furthermore, in some embodiments, in the first reaction, the molar ratio of the amino ionic liquid to the diisocyanate compound is 1:(2.0-2.1); in the second reaction, the molar ratio of the first intermediate compound, the diamine compound and the diisocyanate compound is 1:(1.5-1.7):(0.5-0.6), that is, the molar ratio of the isocyanate group to the amino group in the second reaction is approximately 1:(1.0-1.1).

[0087] The present application prepares the polymer by the above-mentioned preparation method, which not only can obtain a polymer with excellent comprehensive properties, but also the preparation method is simple to operate and is suitable for large-scale production.

[0088] A second aspect of the present application provides a composite electrolyte, which includes an inorganic solid electrolyte and the polymer of the first aspect of the present application.

[0089] The present application does not particularly limit the inorganic solid electrolyte. The inorganic solid electrolyte can be an inorganic solid electrolyte commonly used in the art. For example, the inorganic solid electrolyte can be selected from at least one of lithium lanthanum zirconium oxide (LLZO), lithium lanthanum zirconium tantalum oxide (LLZTO), lithium aluminum titanium phosphate (LATP) and lithium aluminum germanium phosphate (LAGP).

[0090] In the present application, the polymer may form a polymer electrolyte, so that the composite electrolyte includes an inorganic solid electrolyte and a polymer electrolyte.

[0091] In the composite electrolyte membrane prepared by the prior art, the polymer of the polymer electrolyte is usually polyacrylonitrile (PAN), polyethylene oxide (PEO), polyvinylidene fluoride (PVDF) and polymethacrylate (PMMA), etc. The ionic conductivity and mechanical strength of the composite electrolyte are low; and the interface compatibility between the polymer electrolyte and the inorganic solid electrolyte is poor, which will cause obvious interface impedance inside the composite electrolyte, affecting the transmission of lithium ions between the polymer electrolyte and the inorganic solid electrolyte, thereby reducing the electrochemical performance of the composite electrolyte. Compared with the prior art, the composite electrolyte of the present application includes a polymer with a special structure in the first aspect and an inorganic solid electrolyte, has excellent ionic conductivity and mechanical strength, and the interface compatibility between the polymer electrolyte and the inorganic solid electrolyte in the composite electrolyte is excellent, so the composite electrolyte can significantly improve the electrochemical performance of the battery and extend the service life of the battery.

[0092] Furthermore, in some embodiments of the present application, when the mass percentage of the polymer is 10 to 30% based on the total mass of the composite electrolyte, and the mass percentage of the inorganic solid electrolyte is greater than 0% and less than 90%, the role of the polymer can be fully utilized while saving the polymer, thereby improving the total mass of the composite electrolyte.

[0093] In some embodiments of the present application, the composite electrolyte further includes a lithium salt; based on the total mass of the composite electrolyte, the mass percentage of the lithium salt is 1 to 10%.

[0094] When the composite electrolyte also includes a lithium salt, the lithium salt can better combine with the polymer to form a polymer electrolyte, resulting in a composite electrolyte comprising a polymer electrolyte and an inorganic solid electrolyte. This composite electrolyte exhibits superior ion mobility and ion conductivity. In particular, when the mass percentage of lithium salt in the composite electrolyte is 1-10%, the lithium salt can interact better with the polymer while conserving lithium salt, thereby improving the ion mobility and ion conductivity of the composite electrolyte.

[0095] In some embodiments, when the mass percentage of the polymer in the composite electrolyte is 10-30%, the mass percentage of the lithium salt is 1-10%, and the mass percentage of the inorganic solid electrolyte is 60-89%, the composite electrolyte has better comprehensive performance.

[0096] The present application does not particularly limit the lithium salt, and may be any lithium salt commonly used in the art. For example, the lithium salt may be selected from at least one of lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium difluorooxalatoborate (LiDFOB), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium bis(oxalatoborate) (LiBOB), and lithium bis(difluorosulfonyl)imide (LiFSI).

[0097] It is understood that the present application can directly add lithium salt during the preparation of the composite electrolyte, or can add lithium salt in the form of electrolyte during the preparation of the battery.

[0098] In some embodiments of the present application, the composite electrolyte further includes plastic crystals, and the mass percentage of the plastic crystals is 1 to 10% based on the total mass of the composite electrolyte.

[0099] The present application does not particularly limit the plastic crystal, and the plastic crystal may be a plastic crystal commonly used in the art. For example, the plastic crystal may be succinonitrile.

[0100] The present application utilizes the good physical interaction between succinonitrile and the electron-rich components (such as oxygen elements, ester groups, etc.) in the composite electrolyte to improve the dynamic bond network structure in the composite electrolyte, so that the composite electrolyte has better physical and mechanical strength; and the use of succinonitrile can further enhance the interfacial bonding between the organic electrolyte and the inorganic solid electrolyte, reduce the internal impedance of the composite solid electrolyte, and improve the transmission of lithium ions at the interface; at the same time, the strong polarity of succinonitrile and polyurea can produce good adsorption of anionic groups, reduce the migration of anionic groups in the composite electrolyte, and make the transmission resistance of lithium ions in the composite electrolyte smaller, thereby achieving rapid transmission. Furthermore, when the mass percentage of plastic crystal in the composite electrolyte is 1-10%, the plastic crystal can interact better with lithium salts and / or inorganic solid electrolytes while saving plastic crystal, thereby improving the comprehensive performance of the composite electrolyte. In some embodiments, when the mass percentage of the polymer in the composite electrolyte is 10-30%, the mass percentage of the inorganic solid electrolyte is 50-88%, the mass percentage of the plastic crystal is 1-10%, and the mass percentage of the lithium salt is 1-10%, the composite electrolyte has more excellent comprehensive performance.

[0101] The present application does not particularly limit the preparation method of the composite electrolyte, and those skilled in the art can freely select a manufacturing method corresponding to the purpose.

[0102] In the present application, the composite electrolyte can be obtained by self-supporting film formation, such as by casting the raw material system on a release film, curing it to form a film, and then peeling it off. It can also be obtained by extruding the raw material system into a film.

[0103] In some embodiments, the composite electrolyte can be prepared by a method comprising the following steps: adding an inorganic solid electrolyte to a first solvent to obtain a first mixed liquid; adding a polymer to a second solvent to obtain a second mixed liquid; completely mixing the first mixed liquid and the second mixed liquid to obtain a third mixed liquid; pouring the third mixed liquid as a raw material system onto the surface of a release film, and then removing the first solvent and the second solvent, and separating the third mixed liquid from the release film to obtain a composite electrolyte.

[0104] The present application has no particular limitation on the first solvent and the second solvent, which can be selected from commonly used solvents, such as N-methylpyrrolidone (NMP), acetone, methanol, ethanol, and the like.

[0105] In some embodiments, the method for preparing the composite electrolyte may further include the following steps: adding lithium salt to a third mixed solution obtained by completely mixing the first mixed solution and the second mixed solution, and stirring the mixture sufficiently to obtain a uniformly mixed raw material system.

[0106] In some embodiments, the preparation method of the composite electrolyte may further include the following steps: adding lithium salt and plastic crystal to a third mixed solution obtained by completely mixing the first mixed solution and the second mixed solution, and stirring thoroughly to obtain a uniformly mixed raw material system.

[0107] A third aspect of the present application provides a separator comprising a porous substrate, and the polymer of the first aspect or the composite electrolyte of the second aspect disposed on at least a portion of the surface of the porous substrate and / or in at least a portion of the pores of the porous substrate.

[0108] It can be understood that in the membrane of the present application, the polymer can be arranged on part of the surface or the entire surface of the porous matrix, or in part of the pores or the entire pores of the porous matrix; or the composite electrolyte can be arranged on part of the surface or the entire surface of the porous matrix, or in part of the pores or the entire pores of the porous matrix.

[0109] The present application does not limit the specific arrangement method. The arrangement method commonly used in the art can be used to arrange the polymer or composite electrolyte on at least part of the surface of the porous matrix and / or in at least part of the pores of the porous matrix to form a diaphragm.

[0110] In some embodiments, the separator can be obtained by coating a raw material system of a polymer or composite electrolyte on a porous substrate and curing it, or by hot pressing or rolling a self-filming polymer or composite electrolyte with a porous substrate to obtain a separator, wherein the porous substrate can be any conventional porous substrate used for battery separators. For example, the porous substrate can be a film or fabric substrate formed by any of the following polymers, and the polymer can be selected from at least one of polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene naphthalene, polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, tetrafluoropropylene copolymer, and hexafluoropropylene copolymer; or can be selected from at least one of copolymers, homopolymers, and derivatives of propylene, 1-butene, pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene.

[0111] In some embodiments, it can be prepared by a method comprising the following steps: adding an inorganic solid electrolyte to a first solvent to obtain a first mixed liquid; adding a polymer to a second solvent to obtain a second mixed liquid; completely mixing the first mixed liquid and the second mixed liquid to obtain a third mixed liquid; coating the third mixed liquid as a raw material system on at least a portion of the surface of the porous substrate, and then heating and drying to remove the first solvent and the second solvent to obtain a diaphragm.

[0112] The present application has no particular limitation on the first solvent and the second solvent, and they can be selected from common solvents, such as N-methylpyrrolidone (NMP), acetone, methanol, ethanol, and the like.

[0113] In some embodiments, the preparation process of the separator may further include the following steps: adding lithium salt to the third mixed solution after the first mixed solution and the second mixed solution are completely mixed, and stirring thoroughly to obtain a uniformly mixed raw material system.

[0114] In some embodiments, the preparation process of the separator may further include the following steps: adding lithium salt and plastic crystal to the third mixed solution after the first mixed solution and the second mixed solution are completely mixed, and stirring thoroughly to obtain a uniformly mixed raw material system.

[0115] In some embodiments, the preparation process of the separator may further include the following steps: the separator obtained after drying is subjected to a roller pressing process to make the polymer or composite electrolyte more tightly bonded to the porous matrix.

[0116] The diaphragm of the present application, since it includes the above-mentioned polymer or composite electrolyte, can improve the electrochemical performance of the battery and broaden the application scenarios of the battery when applied to the battery.

[0117] A fourth aspect of the present application provides a battery, comprising the polymer of the first aspect;

[0118] or, comprising the composite electrolyte of the second aspect;

[0119] Or, comprising the diaphragm of the third aspect.

[0120] It can be understood that the battery of the present application also includes a positive electrode sheet, a negative electrode sheet and an outer packaging.

[0121] In the present application, the positive electrode sheet, the composite electrolyte (or separator) and the negative electrode sheet can be stacked to obtain an electrode assembly, and the electrode assembly can be placed in an outer package and sealed to obtain a battery.

[0122] Since the battery of the present application includes the above-mentioned composite electrolyte, it has excellent electrochemical performance and excellent user experience, and is suitable for wide promotion and application.

[0123] The technical solution of this application is described in detail below through specific embodiments.

[0124] 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 the conventional experimental steps or conditions described in the prior art.

[0125] (1) Amino ionic liquids:

[0126] 1-Aminopropyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt (CAS:1013932-26-7);

[0127] 1-aminoethyl-3-methylimidazolium tetrafluoroborate (CAS: 897965-53-6);

[0128] The above amino ionic liquids were purchased from Qingdao Aolic New Material Technology Co., Ltd.

[0129] (2) Diisocyanate compounds:

[0130] Hexamethylene diisocyanate (CAS: 822-06-0);

[0131] Diphenylmethane-4,4'-diisocyanate (CAS: 101-68-8);

[0132] 1,12-Tridecane diisocyanate (CAS: 13879-35-1);

[0133] The above diisocyanate compounds were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0134] (3) Diamine compounds:

[0135] Polyetheramine D230 (CAS: 9046-10-0);

[0136] 2,2'-diethyldisulfide (CAS: 56-17-7);

[0137] 4,4'-Diaminodicyclohexylmethane (CAS: 1761-71-3)

[0138] The above diamine compounds were purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0139] (4) Plastic crystal materials:

[0140] Succinonitrile (CAS: 110-61-2)

[0141] The above-mentioned plastic crystal materials were purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0142] Example 1

[0143] The battery of this embodiment is prepared by a method comprising the following steps:

[0144] 1) Preparation of polymer

[0145] The amino ionic liquid and the diisocyanate compound are subjected to a first reaction to obtain a first intermediate compound; a diamine compound is gradually added, and then the diisocyanate compound is gradually added to carry out a second reaction to obtain a polymer;

[0146] The amino ionic liquid is 1-aminopropyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, the diisocyanate compound is hexamethylene diisocyanate, and the diamine compound is 4,4'-diaminodiphenylmethane;

[0147] In the first reaction, the molar ratio of amino ionic liquid to diisocyanate compound was 1:1.05, the reaction temperature was 5°C, and the reaction time was 120 min;

[0148] In the second reaction, the molar ratio of the first intermediate product, the diisocyanate compound, and the diamine compound is 1:1.5:0.5. The reaction temperature is 5°C and the reaction time is 240 minutes.

[0149] 2) Preparation of composite electrolyte

[0150] dispersing an inorganic solid electrolyte in an NMP solvent to obtain a first dispersion;

[0151] Dissolving the polymer in step 1) in NMP solvent to obtain a first solution;

[0152] Completely mixing the first dispersion and the first solution to obtain a second solution;

[0153] Then, succinonitrile and lithium salt were added to the second solution and stirred for 1 hour to obtain a uniformly mixed raw material system;

[0154] The raw material system is applied to at least a portion of the surface of the porous substrate, and then heated and dried to remove the NMP solvent to obtain a composite electrolyte;

[0155] Among them, the inorganic solid electrolyte is LATP, the lithium salt is lithium hexafluorophosphate, and the porous matrix is ​​a PET non-woven porous membrane;

[0156] In the composite electrolyte, the mass percentage of the inorganic solid electrolyte is 60%, the mass percentage of the lithium salt is 5%, the mass percentage of the plastic crystal is 5%, and the mass percentage of the polymer is 30%.

[0157] 3) Battery preparation

[0158] The positive electrode sheet, the composite electrolyte and the negative electrode sheet are stacked to obtain an electrode assembly, and the electrode assembly is placed in an aluminum-plastic film and sealed to obtain a battery;

[0159] 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, a conductive agent Super P, and a binder PVDF. The mass ratio of lithium cobalt oxide, the conductive agent, and the binder is 96:2:2.

[0160] The negative electrode sheet includes a copper foil and a negative electrode active layer arranged on the surface of the copper foil. The negative electrode active layer includes silicon-doped graphite, a conductive agent Super P, and a binder PAA. The mass ratio of the silicon-doped graphite, the conductive agent, and the binder is 95:2:3.

[0161] Example 2

[0162] The preparation method of the battery of this embodiment is basically the same as that of embodiment 1, except that:

[0163] 1) Preparation of polymer

[0164] The diisocyanate compound is diphenylmethane-4,4'-diisocyanate.

[0165] Example 3

[0166] The preparation method of the battery of this embodiment is basically the same as that of embodiment 1, except that:

[0167] 1) Preparation of polymer

[0168] The diamine compound is polyetheramine D230.

[0169] Example 4

[0170] The preparation method of the battery of this embodiment is basically the same as that of embodiment 1, except that:

[0171] 1) Preparation of polymer

[0172] The amino ionic liquid is 1-aminoethyl-3-methylimidazolium tetrafluoroborate, the diisocyanate compound is 1,12-diisocyanatotridecane, and the diamine compound is 2,2'-dithiodiethylamine.

[0173] Example 5

[0174] The preparation method of the battery of this embodiment is basically the same as that of embodiment 1, except that:

[0175] 1) Preparation of polymer

[0176] In the first reaction, the amino ionic liquid is 1-aminoethyl-3-methylimidazolium tetrafluoroborate, and the diisocyanate compound is 1,12-diisocyanatotridecane;

[0177] In the second reaction, the diamine compound is polyetheramine D230, and the diisocyanate compound is diphenylmethane-4,4'-diisocyanate.

[0178] Example 6

[0179] The preparation method of the battery of this embodiment is basically the same as that of embodiment 1, except that:

[0180] 1) Preparation of polymer

[0181] In the first reaction, the diisocyanate compound is hexamethylene diisocyanate and 1,12-diisocyanatotridecane (the molar ratio of hexamethylene diisocyanate to 1,12-diisocyanatotridecane is 1:1);

[0182] In the second reaction, the diamine compound is 4,4'-diaminodicyclohexylmethane, and the diisocyanate compound is diphenylmethane-4,4'-diisocyanate.

[0183] Example 7

[0184] The preparation method of the battery of this embodiment is basically the same as that of embodiment 1, except that:

[0185] 2) Preparation of composite electrolyte

[0186] No succinonitrile added;

[0187] In the composite electrolyte, the mass percentage of the inorganic solid electrolyte is 65%, the mass percentage of the lithium salt is 5%, and the mass percentage of the polymer is 30%.

[0188] Comparative Example 1

[0189] The preparation method of the battery of this comparative example is basically the same as that of Example 1, except that:

[0190] 1) Preparation of polymer

[0191] The amino ionic liquid, the diisocyanate compound and the diamine compound are added into a reaction container simultaneously to prepare a polymer by a one-pot method;

[0192] Wherein, the molar ratio of amino ionic liquid, diisocyanate compound and diamine compound is 1:2.1:1.1;

[0193] The reaction temperature was 5°C and the reaction time was 240 min.

[0194] Comparative Example 2

[0195] The preparation method of the battery of this comparative example is basically the same as that of comparative example 1, except that:

[0196] 1) Preparation of polymer

[0197] The diisocyanate compound is diphenylmethane-4,4'-diisocyanate.

[0198] Comparative Example 3

[0199] The preparation method of the battery of this comparative example is basically the same as that of Example 1, except that:

[0200] 1) Preparation of polymer

[0201] Without containing amino ionic liquid, the diisocyanate compound and the diamine compound are directly reacted to obtain a polymer;

[0202] The molar ratio of the diisocyanate compound to the diamine compound is 1:1.1, the reaction temperature is 5°C, and the reaction time is 240 min.

[0203] Comparative Example 4

[0204] The preparation method of the battery of this comparative example is basically the same as that of comparative example 1, except that:

[0205] 2) Preparation of composite electrolyte

[0206] No plastic crystal materials are added;

[0207] In the composite electrolyte, the mass percentage of the inorganic solid electrolyte is 65%, the mass percentage of the lithium salt is 5%, and the mass percentage of the polymer is 30%.

[0208] Performance Testing

[0209] The following performance tests were performed on the polymers, composite electrolytes, and batteries in the examples and comparative examples, and the test results are shown in Table 1.

[0210] 1. Infrared test

[0211] FIG1 is an infrared test curve of the polymer in Example 2 of the present application. As shown in FIG1 , in the infrared test curve of the polymer in Example 2 of the present application, 3304 cm -1 and 1637cm -1 The absorption peaks at 1508 cm are the stretching vibration absorptions of NH and C=O in the urea group; -1 and 1593cm -1 The absorption peak comes from the vibration absorption of the benzene ring; 3033cm -1 The absorption peak at 839 cm is the stretching vibration absorption of the CH bond on the benzene ring. -1 The strong absorption peak at 1537cm comes from the out-of-plane bending vibration absorption of the CH bond in the benzene ring, and the benzene ring is 1,4-substituted; -1 The absorption peak at 1177 cm comes from the skeleton vibration absorption of the imidazole ring. -1 The peak at 2856cm is the stretching vibration absorption peak of the imidazole ring; -1 and 2931cm -1 The absorption peak at 1408cm is the stretching vibration absorption peak of methyl and methylene; -1 The absorption peak at 1230 cm comes from the vibration absorption of the tertiary amine bond. -1 The absorption peak is the stretching vibration absorption of the CN bond, appearing at 1304 cm -1 The absorption peak at is the vibration absorption of the CN bond in the aromatic amine. This proves that Example 2 of the present application successfully prepared the polymer having the structural formulas shown in Formula 1 and Formula 2.

[0212] 2. Room temperature ionic conductivity

[0213] The test is carried out using the method specified in the "Test Method for Ionic Conductivity of Power Battery Membranes" (industry standard NB / T 10827-2021).

[0214] 3. Battery cycle performance

[0215] The test is carried out in accordance with the methods specified in the national standard GB / T31486-2015 "Electrical Performance Requirements and Test Methods for Power Batteries for Electric Vehicles".

[0216] 4. Limiting oxygen index

[0217] The test is carried out in accordance with the methods specified in GB / T2406.1-2008 "Plastics - Determination of Combustion Behavior by Oxygen Index Method - Part 1: Guidelines" and GB / T2406.2-2009 "Plastics - Determination of Combustion Behavior by Oxygen Index Method - Part 2: Room Temperature Test".

[0218] 5. Internal impedance

[0219] The internal impedance of the battery is characterized according to the electrochemical impedance test method in TSPSTS 019-2021 "Performance Requirements and Test Methods for Solid Electrolytes for Solid-State Lithium Batteries-Inorganic Oxide Solid Electrolytes" and TSPSTS 020-2021 "Performance Requirements and Test Methods for Solid-State Electrolytes for Solid-State Lithium Batteries-Polymer and Composite Solid Electrolytes".

[0220] 6. Tensile strength

[0221] The tensile strength of the composite electrolyte was measured according to the standard test method of ASTM D638-14 “Standard Test Method for Tensile Properties of Plastics”.

[0222] Table 1

[0223] As shown in Table 1, the composite electrolyte prepared from the polymer of the embodiment of the present application has excellent room temperature ionic conductivity, limiting oxygen index, and tensile strength. When used in a battery, the composite electrolyte can improve the battery's capacity retention rate, reduce the battery's internal impedance, and enable the battery to have excellent overall performance.

[0224] Furthermore, according to Example 1 and Comparative Example 1, it can be seen that the ionic conductivity of the composite electrolyte (Example 1) prepared by the polymer comprising the first block shown in Formula 1 and the second block shown in Formula 2 in the present application is better than that of the composite electrolyte (Comparative Example 1) obtained by the polymer having a disordered structure, and when applied to a battery, the battery in Example 1 has a better cycle capacity retention rate and a lower internal impedance, indicating that polymers with higher regularity and block structure help to improve the comprehensive performance of the composite electrolyte, thereby improving the comprehensive performance of the battery.

[0225] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A polymer, wherein, The polymer includes a first block represented by Formula 1 and a second block represented by Formula 2; Among them, R1 is selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted polyether group, substituted or unsubstituted C1-C30 alkoxy, 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, substituted or unsubstituted C6-C60 aryl, *-b1-S-S-b2-*; b1 and b2 are each independently selected from substituted or unsubstituted C2-C15 linear alkyl or substituted or unsubstituted C6-C60 aryl; R3 is an ionic liquid group; m≥1, n≥1, and both are integers.

2. The polymer according to claim 1, wherein, When the polymer includes a plurality of the first blocks of the formula 1, at least one of the following is satisfied: a) R3 in the plurality of the first blocks is selected from the same ionic liquid group; b) R1 in the plurality of the first blocks is selected from the same group.

3. The polymer according to claim 1, wherein, When the polymer includes a plurality of the second blocks of the formula 2, R1 in the plurality of the second blocks is selected from the same group and R2 in the plurality of the second blocks is selected from the same group.

4. The polymer according to any one of claims 1-3, wherein, The R3 is selected from one of imidazole-based ionic liquid groups, pyridine-based ionic liquid groups, quaternary ammonium-based ionic liquid groups or quaternary phosphonium-based ionic liquid groups.

5. The polymer according to claim 4, wherein, R3 is selected from any one of the following groups; Among them, R4 is selected from substituted or unsubstituted C1-C30 alkyl groups, 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, At least one of the following is satisfied: a) R1 in the first block is a chain structure; b) R2 in the second block contains a cyclic structure.

7. The polymer according to any one of claims 1-6, wherein, The polymer is prepared by a method including the following steps: Performing a first reaction on an amino ionic liquid and a diisocyanate compound to obtain a first intermediate compound; Performing a second reaction on the first intermediate compound, a diamine compound and a diisocyanate compound to obtain the polymer.

8. A composite electrolyte, wherein, The composite electrolyte includes an inorganic solid electrolyte and the polymer according to any one of claims 1-7.

9. The composite electrolyte according to claim 8, wherein, Based on the total mass of the composite electrolyte, the mass percentage content of the polymer is 10-30%, and the mass percentage content of the inorganic solid electrolyte is greater than 0% and less than 90%.

10. The composite electrolyte according to claim 8 or 9, wherein It further includes a lithium salt, and based on the total mass of the composite electrolyte, the mass percentage content of the lithium salt is 1-10%.

11. The composite electrolyte according to claim 10, wherein, It further includes a plastic crystal, and based on the total mass of the composite electrolyte, the mass percentage content of the plastic crystal is 1-10%.

12. A diaphragm, wherein, It includes a porous matrix, and the polymer according to any one of claims 1-7 or the composite electrolyte according to any one of claims 8-11 provided on at least part of the surface of the porous matrix and / or at least part of the pores of the porous matrix.

13. A battery, wherein, It includes the polymer according to any one of claims 1-7; Or, it includes the composite electrolyte according to any one of claims 8-11; Or, it includes the separator according to claim 12.

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