A high-temperature resistant polymer, a high-temperature resistant polymer film, and a lithium battery

Abstract

This invention provides a high-temperature resistant polymer, a high-temperature resistant polymer film, and a lithium battery. The high-temperature resistant polymer film provided by this invention can be obtained by addition polymerization of cyclic polyamines and multi-functional activated alkynes. The process is simple and can be carried out at room temperature or in air. Furthermore, this polymerization reaction does not require a catalyst, avoiding the introduction of other impurities. This not only simplifies the formulation but also avoids electrode side reactions that may be caused by catalyst residue. The resulting polymer film has a cross-linked, regular honeycomb chemical network structure and good high-temperature dimensional stability, showing no significant dimensional shrinkage after heating at 200°C for 1 hour.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery technology, specifically relating to a high-temperature resistant polymer, a high-temperature resistant polymer film, and a lithium battery. Background Technology

[0002] Lithium-ion batteries, due to their high energy density and long cycle life, are widely used in portable electronic devices, electric vehicles, and energy storage devices, showing great promise for future applications. In recent years, with the increasing demand for electric vehicles and large-scale energy storage systems, the requirements for battery energy density, charge / discharge rate, and safety have also become increasingly stringent. A lithium-ion battery typically consists of a positive electrode, a negative electrode, a separator, an electrolyte, and a battery casing. Among these, the separator, as the material separating the positive and negative electrodes, is a crucial component ensuring battery safety. To meet battery performance requirements, the separator needs to possess suitable mechanical strength, high porosity, resistance to electrochemical oxidation, and good electrolyte wettability.

[0003] Currently, most commercially available separators are polyolefin-based, including polyethylene (PE), polypropylene (PP), and PP / PE / PP three-layer composite separators. Polyolefin separators are widely used due to their lower price and good chemical stability and mechanical properties. However, their low polarity and low surface energy result in poor electrolyte wetting, leading to low lithium-ion conductivity. Furthermore, these separators have poor temperature resistance; under overcharging, discharging, or high-temperature conditions, they can shrink significantly or even melt, causing direct contact and short circuits between the positive and negative electrodes, potentially leading to safety accidents. Therefore, current mainstream polyolefin separators can no longer meet the demands of lithium batteries for wider application and safety, making the development of separators with lower internal resistance and higher temperature resistance an inevitable trend.

[0004] To improve the thermal stability of separators, a widely adopted method is to use an organic / inorganic material composite strategy, coating an inorganic filler layer, such as alumina, zirconium oxide, silicon oxide, titanium oxide, and magnesium oxide, onto a polyolefin-based membrane. Patent CN102181204A discloses a method for preparing high-temperature resistant separators by coating with high-temperature resistant powder. Because inorganic powder coatings possess high thermal stability and mechanical properties, they significantly improve battery safety. However, this coating method also greatly increases the weight and thickness of the separator. Furthermore, composite modification methods not only require complex formulations but also involve complex preparation processes, including dispersion, slurry preparation, filtration, coating, and drying. The complex processing also faces challenges such as low adhesion strength between the inorganic filler coating and the polyolefin-based membrane, and easy detachment of inorganic particles.

[0005] Given the various problems with composite modified polyolefin membranes, researchers have turned their attention to finding new materials to replace polyolefins as membrane substrates. Polyimide, as a high-temperature resistant material with excellent comprehensive properties, can be used at temperatures exceeding 300℃ and has no obvious melting point. It also possesses high insulation properties, making it a promising high-temperature resistant membrane material. He et al. synthesized various polyimide membranes using monomers with different structures and found that their thermal dimensional stability, electrolyte wettability, and electrolyte absorption were all superior to those of polypropylene membranes (Electrochimica Acta, 2020, 337, 135838). However, current methods for preparing polyimide membranes are still limited to the laboratory, including template methods, phase separation methods, and electrospinning methods. These processes are complex and costly, limiting their production and application. Crosslinked polymers are also a typical class of materials with high-temperature stability; therefore, preparing crosslinked polymer films with porous structures is another strategy for preparing high-temperature resistant membranes. Patent CN105280866A discloses a method for preparing cross-linked polyurethane membranes by foaming polyether polyols and isocyanates. The membranes have a thickness of 5-41 μm and a porosity of 70-75%, exhibiting advantages such as high porosity, low thickness, high liquid absorption, and low electrical resistance. However, the preparation process remains relatively complex, requiring multiple steps including foaming, slicing, and stamping. Furthermore, controlling the foaming process is difficult, and uneven foaming voids are prone to occur. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a high-temperature resistant polymer, a high-temperature resistant polymer film, and a lithium battery. The high-temperature resistant polymer film exhibits excellent thermal stability and is simple to prepare.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a high-temperature resistant polymer, which is obtained by polymerization of cyclic polyamines and multi-activated acetylenes;

[0009] The molar ratio of the cyclic polyamine to the poly-activated acetylene is 1:0.8 to 1:1.2, preferably 1:1;

[0010] The cyclic polyamine is a substituted or unsubstituted C4-C30 cycloalkanes containing two or more -NH- groups;

[0011] The poly-activated alkyne is obtained by reacting a polyol with propargyl acid, wherein the polyol contains two or more -OH groups.

[0012] Preferably, at least one of the cyclic polyamines and poly-activated alkynes includes three or more functional groups.

[0013] Preferably, the cyclic polyamine is selected from any one or more of the following formulas 1 to 8:

[0014]

[0015] Preferably, the polyol is selected from any one or more of ethylene glycol, 1,4-butanediol, glycerol, 1,2,4,5-tetrahydroxybenzene, dipentaerythritol, or polymer-based polyols.

[0016] Preferably, the polymer-based polyol is selected from any one or more of polyether polyols, polycarbonate polyols, polycarbonate ether polyols, or polyester polyols.

[0017] Preferably, the polymerization is carried out in the presence of a solvent.

[0018] Preferably, the solvent is selected from any one or more of dichloromethane, chloroform, N,N-dimethylformamide, tetrahydrofuran, ethanol, or water.

[0019] Secondly, the present invention provides a high-temperature resistant polymer film, which is composed of the high-temperature resistant polymer involved in the above-mentioned technical solution;

[0020] Preferably, the thickness of the high-temperature resistant polymer film is 5–50 μm.

[0021] Thirdly, the present invention provides a lithium battery comprising a positive electrode, a negative electrode, and a separator; the separator is a high-temperature resistant polymer film involved in the above-mentioned technical solution.

[0022] Preferably, the positive electrode comprises any one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, or lithium nickel cobalt oxide.

[0023] Preferably, the negative electrode comprises any one of lithium, graphite, soft carbon, hard carbon, or silicon.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) Existing mainstream polyolefin separators on the market have poor thermal stability and cannot be used at high temperatures or for long periods of time. They are prone to dimensional shrinkage, which can cause internal short circuits. The high-temperature resistant polymer film provided by this invention can be obtained by addition polymerization of cyclic polyamines and poly-activated alkynes. The process is simple and can be carried out at room temperature or in air. At the same time, this polymerization reaction does not require a catalyst, avoiding the introduction of other impurities. This not only simplifies the formulation but also avoids electrode side reactions that may be caused by catalyst residue. The resulting polymer film has a cross-linked, regular honeycomb chemical network structure and good high-temperature dimensional stability. It does not show significant dimensional shrinkage when heated at 200°C for 1 hour.

[0026] (2) Compared to the high temperature and high pressure conditions required in the preparation of polyolefin materials, the click reaction of activated alkynes in this invention can achieve the click reaction of multi-functional activated alkynes and cyclic polyamines within a few minutes at room temperature and in air. At the same time, this reaction does not require a catalyst, avoiding the introduction of other impurities, which not only simplifies the formulation but also avoids electrode side reactions that may be caused by catalyst residue;

[0027] (3) Existing technologies for preparing cross-linked polymer membranes involve complex processing steps, including pore making, slicing, and pressing. However, this invention utilizes the inherent micropores resulting from the regular honeycomb chemical network structure of high-temperature resistant polymers, avoiding the complex pore-making process. A porous membrane can be prepared using a simple solution casting method, enabling the wetting and absorption of electrolyte.

[0028] Tests showed that lithium batteries using the aforementioned high-temperature resistant polymer film as the separator exhibited significantly improved ionic conductivity and electrochemical stability. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] This invention provides a high-temperature resistant polymer obtained by polymerizing a cyclic polyamine and a multi-component activated acetylene. The amino group in the cyclic polyamine undergoes an addition reaction with the acetyl group in the multi-component activated acetylene to generate an alkenyl group. In this invention, the molar ratio of the cyclic polyamine to the multi-component activated acetylene is 1:0.8 to 1:1.2, preferably 1:0.9 to 1:1.1, and more preferably 1:1.

[0031] The cyclic polyamine is a C4-C30 cycloalkanes containing two or more -NH- groups, either substituted or unsubstituted, to obtain a polymer with a cross-linked network structure. The substituted or unsubstituted groups are selected from C1-C6 alkyl groups.

[0032] In some specific embodiments of the present invention, the cyclic polyamine may be selected from any one or more of the following formulas 1 to 8:

[0033]

[0034] Among them, the substance represented by Formula 1 is piperazine; the substance represented by Formula 2 is high piperazine; the substance represented by Formula 3 is 6-methyl-1,4-diazacycloheptane; the substance represented by Formula 4 is 1,4,7-triazacyclononane; the substance represented by Formula 5 is cyclotinocyanine; the substance represented by Formula 6 is 2,5,8,11-tetramethyl-1,4,7,10-pentazazepinedecane; the substance represented by Formula 7 is 1,4,8,11-tetraazacyclotetradecane; and the substance represented by Formula 8 is 1,4,7,10,13-pentazazepinedecane.

[0035] In this invention, the poly-activated alkyne is obtained by reacting a polyol with propargyl acid, wherein the polyol contains two or more -OH groups. Specifically, the polyol includes, but is not limited to, any one or more of ethylene glycol, 1,4-butanediol, glycerol, 1,2,4,5-tetrahydroxybenzene, dipentaerythritol, or polymer-based polyols; the polymer-based polyol is selected from any one or more of polyether polyols, polycarbonate polyols, polycarbonate ether polyols, or polyester polyols. In some embodiments of this invention, preferably, the polyol and propargyl acid react under the action of a catalyst, whereby the hydroxyl groups in the polyol react with the carboxyl groups in the propargyl acid to form an ester bond. The catalyst may be selected from any one or more of p-toluenesulfonic acid, 4-dimethylaminopyridine, concentrated sulfuric acid, thionyl chloride, etc.

[0036] It should be noted that, in order to enable the high-temperature resistant polymer to have a more regular honeycomb chemical network structure, thereby forming micropores, the present invention preferably uses cyclic polyamines and multi-functional activated alkynes in the reaction process, wherein at least one of the raw materials, cyclic polyamines and multi-functional activated alkynes, includes three or more functional groups.

[0037] The present invention also provides a method for preparing the above-mentioned high-temperature resistant polymer, comprising the following steps:

[0038] Cyclic polyamines and poly-activated acetylenes are polymerized in the presence of a solvent to obtain a high-temperature resistant polymer.

[0039] According to the present invention, a multi-component activated alkyne is first provided. In some embodiments of the present invention, a polyol, propargyl acid, a catalyst, and a solvent are preferably mixed, heated under reflux, and reacted to obtain the multi-component activated alkyne. The polyol and catalyst are as described in the relevant content of the above technical solution and will not be repeated here; the solvent can be selected from toluene. The reflux temperature is 120–180°C, and the reaction is preferably carried out under stirring conditions for 12–20 hours. In some preferred embodiments of the present invention, after the reaction is completed, the product is preferably washed with water and dried to obtain the multi-component activated alkyne.

[0040] Then, according to the present invention, the cyclic polyamine and the multi-functional activated acetylene are polymerized in the presence of a solvent to obtain a high-temperature resistant polymer. The cyclic polyamine and the multi-functional activated acetylene are as described in the relevant content of the above technical solution and will not be repeated here; the solvent is selected from any one or more of dichloromethane, chloroform, N,N-dimethylformamide, tetrahydrofuran, ethanol, or water. The polymerization reaction can be carried out at room temperature or in air, and the polymerization time is 5–30 min, preferably 10–20 min. In the present invention, during the above polymerization reaction, the molar ratio of the cyclic polyamine to the multi-functional activated acetylene is 1:0.8–1:1.2, preferably 1:1. This is to ensure complete reaction of the amino and acetylene groups, resulting in a polymer network with a highly cross-linked structure.

[0041] In some embodiments of the present invention, it is preferable to mix and react a cyclic polyamine solution and a multi-component activated alkyne solution to obtain a high-temperature resistant polymer. The solvents in the cyclic polyamine solution and the multi-component activated alkyne solution are each independently selected from one or more of dichloromethane, chloroform, N,N-dimethylformamide, tetrahydrofuran, ethanol, or water.

[0042] The method for preparing high-temperature resistant polymers provided by this invention utilizes the click reaction of activated alkynes, enabling the click reaction of multi-component activated alkynes with cyclic polyamines to be completed within minutes at room temperature and in air. Furthermore, this reaction requires no catalyst, avoiding the introduction of other impurities, simplifying the formulation, and preventing electrode side reactions that may result from catalyst residue.

[0043] This invention also provides a high-temperature resistant polymer film, which is composed of the high-temperature resistant polymer involved in the above-described technical solution. In this invention, the thickness of the high-temperature resistant polymer film is 5–50 μm, and can be 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 30 μm, 40 μm, or 50 μm, etc. The above values ​​are merely illustrative and not limiting; other values ​​within this range are also applicable.

[0044] The present invention also provides a method for preparing the above-mentioned high-temperature resistant polymer film, comprising:

[0045] Cyclic polyamines and poly-activated acetylenes are polymerized in the presence of a solvent to obtain the reactants.

[0046] Place the reactants in a mold, let stand until solidified, and then dry.

[0047] In some embodiments of the present invention, it is preferable to mix the cyclic polyamine solution and the multi-activated acetylene solution evenly and then quickly pour the mixture into a polytetrafluoroethylene mold, let it stand for 5 to 30 minutes, and then dry it after it has completely solidified to obtain a high-temperature resistant polymer film.

[0048] The present invention conducts liquid absorption, corrosion resistance and thermal shrinkage tests on the obtained high temperature resistant polymer film, and finds that the high temperature resistant polymer film has excellent liquid absorption rate, good resistance to electrolyte corrosion and good thermal stability (no obvious dimensional shrinkage when heated at 200°C for 1 hour).

[0049] Based on the aforementioned excellent properties of the high-temperature resistant polymer film, this invention applies it as a separator in lithium batteries. Therefore, this invention also provides a lithium battery comprising a positive electrode, a negative electrode, and a separator; the separator is the high-temperature resistant polymer film. In some embodiments of this invention, the positive electrode includes lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, and lithium nickel cobalt oxide, etc. In some embodiments of this invention, the negative electrode includes lithium, graphite, soft carbon, hard carbon, and silicon, etc.

[0050] Testing revealed that the ionic conductivity and electrochemical stability of the SS||SS symmetric cell obtained using a high-temperature resistant polymer film as the separator were significantly improved.

[0051] To further illustrate the present invention, the following embodiments provide a detailed description. The experimental materials used in the following embodiments of the present invention are all commercially available products.

[0052] Example 1

[0053] Step 1: Preparation of multi-component activated alkynes

[0054] Glycerol (0.92 g, 10 mmol), propargyl acid (2.52 g, 36 mmol), and p-toluenesulfonic acid (0.10 g, 0.6 mmol) were dissolved in 100 mL of toluene, heated to reflux at 120 °C, and stirred for 12 h. After the reaction was completed, the mixture was washed with water and dried to obtain a ternary activated alkyne.

[0055]

[0056] Step 2: Click polymerization to prepare cross-linked polymer films

[0057] Ternary activated alkyne (2.48 g, 10 mmol) was dissolved in 5 mL of dichloromethane to obtain precursor solution A, and piperazine (1.29 g, 15 mmol) was dissolved in 5 mL of dichloromethane to obtain precursor solution B. After mixing precursor solutions A and B evenly, the mixture was quickly poured into a polytetrafluoroethylene mold, allowed to stand for 30 min, and dried after complete solidification. The resulting film thickness was 8 μm.

[0058] Example 2

[0059] Step 1: Preparation of multi-component activated alkynes

[0060] 1,2,4,5-Tetrahydroxybenzene (1.42 g, 10 mmol), propargyl acid (3.36 g, 48 mmol), and p-toluenesulfonic acid (0.14 g, 0.8 mmol) were dissolved in 100 mL of toluene, heated to reflux at 120 °C, and stirred for 12 h. After the reaction was completed, the mixture was washed with water and dried to obtain a quaternary activated alkyne.

[0061]

[0062] Step 2: Click polymerization to prepare cross-linked polymer films

[0063] A precursor solution A was obtained by dissolving 3.50 g (10 mmol) of quaternary activated alkyne in 4 mL of dichloromethane and B was obtained by dissolving piperazine (2.00 g (20 mmol)) in 5 mL of dichloromethane. After mixing the precursor solutions A and B evenly, the mixture was quickly poured into a polytetrafluoroethylene mold, allowed to stand for 20 min, and dried after complete solidification. The resulting film had a thickness of 10 μm.

[0064] Example 3

[0065] Step 1: Preparation of multi-component activated alkynes

[0066] Dipentaerythritol (2.54 g, 10 mmol), propargyl acid (5.04 g, 72 mmol), and p-toluenesulfonic acid (0.21 g, 1.2 mmol) were dissolved in 100 mL of toluene, heated to reflux at 120 °C, and stirred for 12 h. After the reaction was completed, the mixture was washed with water and dried to obtain a six-membered activated alkyne.

[0067]

[0068] Step 2: Click polymerization to prepare cross-linked polymer films

[0069] Hexa-membered activated alkyne (5.66 g, 10 mmol) was dissolved in 5 mL of dichloromethane to obtain precursor solution A. 6-methyl-1,4-diazacycloheptane (3.42 g, 30 mmol) was dissolved in 6 mL of dichloromethane to obtain precursor solution B. After mixing precursor solutions A and B evenly, the mixture was quickly poured into a polytetrafluoroethylene mold, allowed to stand for 20 min, and dried after complete solidification. The resulting film thickness was 15 μm.

[0070] Example 4

[0071] Step 1: Preparation of multi-component activated alkynes

[0072] Ethylene glycol (0.62 g, 10 mmol), propargyl acid (1.68 g, 24 mmol), and p-toluenesulfonic acid (0.069 g, 0.4 mmol) were dissolved in 10 mL of toluene, heated to reflux at 120 °C, and stirred for 12 h. After the reaction was completed, the mixture was washed with water and dried to obtain a binary activated alkyne.

[0073]

[0074] Step 2: Click polymerization to prepare cross-linked polymer films

[0075] Di-activated alkyne (1.66 g, 10 mmol) was dissolved in 3 mL of dichloromethane to obtain precursor solution A, and 1,4,7-triazacyclononane (0.86 g, 6.67 mmol) was dissolved in 2 mL of dichloromethane to obtain precursor solution B. After mixing precursor solutions A and B evenly, the mixture was quickly poured into a polytetrafluoroethylene mold, allowed to stand for 10 min, and dried after complete solidification. The resulting film thickness was 8 μm.

[0076] Example 5

[0077] Step 1: Preparation of multi-component activated alkynes

[0078] Polyethylene glycol-400 (4.00 g, 10 mmol), propargyl acid (1.68 g, 24 mmol), and p-toluenesulfonic acid (0.069 g, 0.4 mmol) were dissolved in 10 mL of toluene, heated to reflux at 120 °C, and stirred for 12 h. After the reaction was completed, the mixture was washed with water and dried to obtain a binary activated acetylene.

[0079]

[0080] Step 2: Click polymerization to prepare cross-linked polymer films

[0081] Divalent activated acetylene (5.40 g, 10 mmol) was dissolved in 6 mL of water to obtain precursor solution A, and cyclohexane (0.86 g, 5 mmol) was dissolved in 1 mL of water to obtain precursor solution B. After mixing precursor solutions A and B evenly, the mixture was quickly poured into a polytetrafluoroethylene mold, allowed to stand for 10 min, and dried after complete solidification. The resulting film thickness was 15 μm.

[0082] Example 6

[0083] Step 1: Preparation of multi-component activated alkynes

[0084] Polypropylene carbonate diol-1000 (10.00 g, 10 mmol), propargyl acid (1.68 g, 24 mmol), and p-toluenesulfonic acid (0.069 g, 0.4 mmol) were dissolved in 20 mL of toluene, heated to reflux at 120 °C, and stirred for 12 h. After the reaction was completed, the mixture was washed with water and dried to obtain a binary activated acetylene.

[0085]

[0086] Step 2: Click polymerization to prepare cross-linked polymer films

[0087] Divalent activated alkyne (11.40 g, 10 mmol) was dissolved in 6 mL of tetrahydrofuran to obtain precursor solution A. 2,5,8,11-tetramethyl-1,4,7,10-tetraazacyclododecane (1.14 g, 5 mmol) was dissolved in 1 mL of water to obtain precursor solution B. After mixing precursor solutions A and B evenly, the mixture was quickly poured into a polytetrafluoroethylene mold, allowed to stand for 10 min, and dried after complete solidification. The resulting film thickness was 20 μm.

[0088] Example 7

[0089] Step 1: Preparation of multi-component activated alkynes

[0090] Polycarbonate ether polyol (20.00 g, 10 mmol) with a number average molecular weight of 2000 g / mol, propynic acid (1.68 g, 24 mmol), and p-toluenesulfonic acid (0.069 g, 0.4 mmol) were dissolved in 40 mL of toluene, heated to reflux at 120 °C, and stirred for 12 h. After the reaction was completed, the mixture was washed with water and dried to obtain a binary activated yne.

[0091]

[0092] Step 2: Click polymerization to prepare cross-linked polymer films

[0093] Divalent activated alkyne (21.40 g, 10 mmol) was dissolved in 10 mL of tetrahydrofuran to obtain precursor solution A. 1,4,8,11-tetraazacyclotetradecane (1.00 g, 5 mmol) was dissolved in 1 mL of tetrahydrofuran to obtain precursor solution B. After mixing precursor solutions A and B evenly, the mixture was quickly poured into a polytetrafluoroethylene mold, allowed to stand for 30 min, and dried after complete solidification. The resulting film thickness was 40 μm.

[0094] Example 8

[0095] Step 1: Preparation of multi-component activated alkynes

[0096] Polyethylene terephthalate diol (15.00 g, 10 mmol), propargyl acid (1.68 g, 24 mmol), and p-toluenesulfonic acid (0.069 g, 0.4 mmol) with a number average molecular weight of 1500 g / mol were dissolved in 40 mL of toluene, heated to reflux at 120 °C, and stirred for 12 h. After the reaction was completed, the mixture was washed with water and dried to obtain a binary activated acetylene.

[0097]

[0098] Step 2: Click polymerization to prepare cross-linked polymer films

[0099] Di-activated alkyne (16.40 g, 10 mmol) was dissolved in 10 mL of N,N-dimethylformamide to obtain precursor solution A. 1,4,7,10,13-pentazolidinyl pentadecane (0.86 g, 4 mmol) was dissolved in 1 mL of N,N-dimethylformamide to obtain precursor solution B. Precursor solutions A and B were mixed evenly and then quickly poured into a polytetrafluoroethylene mold. After standing for 30 min and allowing it to solidify completely, it was dried. The resulting film thickness was 30 μm.

[0100] Liquid absorption performance test

[0101] The films prepared in Examples 1-8, commercial PE membranes, and PP membranes (as a control) were immersed in electrolyte for 24 hours, then removed. The electrolyte on the surface of the films was absorbed with absorbent paper, and the films were weighed. The liquid absorption rate of the films was calculated based on the weight change before and after immersion. Specific test results are shown in Table 1 below.

[0102] Table 1

[0103] Group Liquid absorption rate (%) Example 1 200 Example 2 213 Example 3 228 Example 4 196 Example 5 240 Example 6 265 Example 7 308 Example 8 289 PE 160 PP 96

[0104] As can be seen from Table 1, the films prepared by this invention have higher liquid absorption rates compared with commercial PE and PP membranes.

[0105] Corrosion resistance test

[0106] The films prepared in Examples 1 to 8 were immersed in electrolyte for 48 hours and then removed to observe the changes in the diaphragms.

[0107] The test results showed that all films exhibited no morphological changes, indicating that the films prepared by this method have good resistance to electrolyte corrosion.

[0108] Heat shrinkage test

[0109] The films prepared in Examples 1-8, commercial PE membranes, and PP membranes (as a control) were placed in ovens at 120°C and 200°C for 1 hour, respectively. Their dimensional shrinkage rates were then measured, and the results are shown in Table 2 below.

[0110] Table 2

[0111]

[0112]

[0113] As can be seen from Table 2, the thermal shrinkage of the film prepared by this invention is greatly improved compared with commercial PE and PP films.

[0114] Ion conductivity test

[0115] The films prepared in Examples 1-8, commercial PE membranes, and PP membranes (as controls) were assembled into SS||SS symmetric cells, and the ionic conductivity at 25°C was measured. The results are shown in Table 3 below.

[0116] Group Ionic conductivity (mS / cm) Example 1 0.70 Example 2 0.75 Example 3 0.77 Example 4 0.69 Example 5 0.72 Example 6 0.88 Example 7 1.02 Example 8 0.93 PE 0.50 PP 0.44

[0117] As can be seen from Table 3, compared with commercial PE and PP membranes, the ionic conductivity of the film prepared by this invention is significantly improved.

[0118] Electrochemical stability test

[0119] The films prepared in Examples 1-8, the commercial PE membrane, and the PP membrane (as a control) were subjected to linear voltammetry scans, and the results are shown in Table 4 below:

[0120] Table 4

[0121] Group Oxidation potential (V) Example 1 4.4 Example 2 4.5 Example 3 4.4 Example 4 4.3 Example 5 4.2 Example 6 4.5 Example 7 4.4 Example 8 4.5 PE 4.2 PP 4.2

[0122] As can be seen from Table 4, the electrochemical stability of the film prepared by this invention is significantly improved compared with commercial PE and PP membranes.

[0123] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-temperature resistant polymer, characterized in that, It is obtained by polymerization of cyclic polyamines and multi-functional activated acetylenes; at least one of the cyclic polyamines and multi-functional activated acetylenes includes three or more functional groups; The molar ratio of the cyclic polyamine to the polyacetylenes is 1:0.8 to 1:1.2; The cyclic polyamine is selected from any one or more of the following formulas 1 to 8: ； The multi-functional activated alkyne is obtained by reacting a polyol with propynic acid.

2. The high-temperature resistant polymer according to claim 1, characterized in that, The polyol is selected from any one or more of ethylene glycol, 1,4-butanediol, glycerol, 1,2,4,5-tetrahydroxybenzene, dipentaerythritol, or polymer-based polyols. The polymer-based polyol is selected from any one or more of polyether polyols, polycarbonate polyols, polycarbonate ether polyols, or polyester polyols.

3. The high-temperature resistant polymer according to claim 1 or 2, characterized in that, The polymerization is carried out in the presence of a solvent.

4. The high-temperature resistant polymer according to claim 3, characterized in that, The solvent is selected from any one or more of dichloromethane, chloroform, N,N-dimethylformamide, tetrahydrofuran, ethanol, or water.

5. A high-temperature resistant polymer film, characterized in that, Composed of the high-temperature resistant polymer according to any one of claims 1 to 4; The thickness of the high-temperature resistant polymer film is 5~50 μm.

6. A lithium battery, characterized in that, Includes positive electrode, negative electrode, and separator; The diaphragm is the high-temperature resistant polymer film as described in claim 5.

7. The lithium battery according to claim 6, characterized in that, The positive electrode includes any one of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganese oxide, or lithium nickel cobalt oxide.

8. The lithium battery according to claim 6 or 7, characterized in that, The negative electrode includes any one of lithium, graphite, soft carbon, hard carbon, or silicon.

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