Epoxy resin polymer electrolyte, preparation method thereof and carbon fiber battery

Abstract

The invention provides an epoxy resin polymer electrolyte, a preparation method thereof and a carbon fiber battery, and relates to the technical field of electrochemical energy storage materials. The epoxy resin polymer electrolyte is prepared from the following raw materials in parts by mass: 10-50 parts of a matrix material, 3-25 parts of a toughening material, 1-10 parts of a short-chain curing agent, 1-10 parts of a long-chain curing agent, 1-8 parts of a flame-retardant reinforcing material and 2-15 parts of lithium trifluoromethanesulfonimide, an integrated carbon fiber battery structure is prepared by adopting the epoxy resin polymer electrolyte and combining a high-voltage RTM (Resin Transfer Molding) process, so that the interface impedance is reduced, the ion transmission efficiency is enhanced, the migration of lithium ions in the battery can be better supported, and the electrochemical performance is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of electrochemical energy storage materials, and in particular to an epoxy resin polymer electrolyte and a preparation method thereof and a carbon fiber battery. Background Art

[0002] Carbon fiber composites are widely used in aerospace and drones due to their excellent mechanical properties and lightweight properties. Most traditional lithium metal batteries use organic liquid electrolytes, which are flammable, volatile, and may decompose or produce harmful gases when heated, resulting in potential dangers in applications with high safety requirements such as aerospace, drones, and electric vehicles. During the circulation of liquid electrolytes, lithium dendrites are more likely to penetrate the diaphragm and cause internal short circuits, seriously affecting battery life and safety. Existing carbon fiber composites are generally only used as structural reinforcements or load-bearing components, and battery functions are usually provided by independent power units, resulting in large space occupation and increased mass of the overall system. It is impossible to achieve an integrated design of "body as battery" and "composite material as energy storage", and the system energy density is low and the structural redundancy is obvious. Solid polymer electrolytes have high mechanical strength and good interface compatibility, which can effectively inhibit the growth of lithium dendrites and improve the safety of batteries. However, in the process of preparing batteries using solid polymer electrolytes, the interaction between the functional groups on the surface of carbon fibers and the solid polymer electrolytes is relatively complex, so it is necessary to improve the material interface bonding strength by modifying or introducing toughening components, and these components will affect the electrolyte's ionic conductivity, flame retardancy, and interfacial compatibility with electrode active materials. Furthermore, there are differences between the existing processes for preparing batteries using solid electrolyte composite molding (such as prepreg, lamination, and curing) and the steps required for battery preparation (such as coating, electrode assembly, electrolyte injection or filling). If the two are simply connected in series, the process is difficult and the yield is low; coordination is required in the overall process design, especially processes such as high-voltage RTM (resin transfer molding), which are combined with the battery's electrochemical functions, and higher requirements are placed on equipment and processes. Based on this, in order to solve the above problems, the present invention proposes an innovative epoxy resin solid polymer electrolyte, which adopts a high-pressure RTM process to integrate the electrolyte and carbon fiber composite materials to achieve structure-energy storage integration. It is particularly suitable for carbon fiber fuselage structures of small and medium-sized unmanned aerial vehicles, portable electronic device casings, aviation composite parts, rail transit composite parts, ship composite parts, automotive composite parts and other resin-based composite material structure-energy storage integrated devices. Summary of the invention

[0003] The purpose of the present invention is to provide an epoxy resin polymer electrolyte and a preparation method thereof and a carbon fiber battery to solve the problems of the traditional lithium metal battery's liquid electrolyte being insufficiently safe, prone to interface problems and lithium dendrites, and affecting battery performance.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides an epoxy resin polymer electrolyte, which is made of the following raw materials in parts by weight:

[0006] 10 to 50 parts of base material, 3 to 25 parts of toughening material, 1 to 10 parts of short-chain curing agent, 1 to 10 parts of long-chain curing agent, 1 to 8 parts of flame retardant reinforcing material and 2 to 15 parts of lithium trifluoromethylsulfonyl imide;

[0007] The matrix material is composed of polyurethane modified epoxy resin and polypropylene glycol diglycidyl ether;

[0008] The toughening material is composed of carboxyl-terminated nitrile rubber and succinonitrile;

[0009] The short-chain curing agent consists of polyetheramine D230 and polyetheramine D400;

[0010] The long-chain curing agent consists of polyetheramine D2000 and polyetheramine T5000;

[0011] The flame retardant reinforcement material consists of hexaphenoxy cyclotriphosphazene and hexachlorocyclotriphosphazene.

[0012] Preferably, the mass ratio of the polyurethane-modified epoxy resin to polypropylene glycol diglycidyl ether in the matrix material is 0.5 to 2:1.

[0013] Preferably, the mass ratio of the terminal carboxyl nitrile rubber to succinonitrile in the toughening material is 0.5 to 2:1.

[0014] Preferably, the mass ratio of polyetheramine D230 to polyetheramine D400 in the short-chain curing agent is 0.5-2:1.

[0015] Preferably, the mass ratio of polyetheramine D2000 to polyetheramine T5000 in the long-chain curing agent is 0.5-2:1.

[0016] Preferably, the mass ratio of hexaphenoxy cyclotriphosphazene to hexachloro cyclotriphosphazene in the flame retardant reinforcing material is 0.5 to 2:1.

[0017] The present invention provides a method for preparing the above epoxy resin polymer electrolyte, comprising the following steps:

[0018] The epoxy resin polymer electrolyte is obtained by mixing a matrix material, a toughening material, a short-chain curing agent, a long-chain curing agent, a flame retardant reinforcing material and lithium trifluoromethylsulfonyl imide.

[0019] The present invention also provides a carbon fiber battery, and the preparation method of the carbon fiber battery comprises the following steps:

[0020] 1) coating the positive electrode active material slurry and the negative electrode active material slurry on the nickel-plated carbon fiber respectively, and drying and curing them in sequence to obtain the carbon fiber battery positive electrode and the carbon fiber battery negative electrode;

[0021] 2) mixing the ultra-thin epoxy resin glass fiber prepreg with the shrinkable filler, and sequentially curing and heating at high temperature to obtain a diaphragm layer;

[0022] 3) Assembling a carbon fiber battery positive electrode, a carbon fiber battery negative electrode, a separator layer and an epoxy resin polymer electrolyte to obtain a carbon fiber battery;

[0023] The epoxy resin polymer electrolyte is an epoxy resin polymer electrolyte.

[0024] Preferably, the positive electrode active material in step 1) is lithium iron phosphate and / or lithium nickel cobalt manganese oxide;

[0025] The negative electrode active material in step 1) is one or more of a carbon-based material or metallic lithium;

[0026] The curing temperature in step 1) is 80-130° C. and the curing time is 3-6 hours;

[0027] Preferably, the shrinkable filler in step 2) comprises one or more of polystyrene foam powder, polylactic acid powder, polycaprolactone powder and phenolic foam powder;

[0028] The curing temperature in step 2) is 80-130°C and the curing time is 3-6h;

[0029] The high temperature heating in step 2) is performed at a temperature of 140 to 180° C. for a time of 1 to 3 hours.

[0030] The present invention has at least the following beneficial effects:

[0031] 1. High initial discharge capacity and long cycle life: By optimizing the ionic conductivity and interface compatibility, the prepared epoxy resin polymer electrolyte system achieves a high initial discharge capacity of 160 mAh / g at a rate of 0.1C, and the capacity retention rate is 95.2% after 100 cycles, which significantly improves the performance stability of the carbon fiber battery and meets the application requirements of long-life batteries.

[0032] 2. Excellent mechanical properties: After the epoxy resin polymer electrolyte is made into a 50μm thick film, its tensile strength reaches 15MPa and its elongation at break is 56.2%, which means it has both toughness and strength. This enables the carbon fiber composite material to have stable mechanical support while carrying both structural and energy storage functions, adapt to large volume changes, and effectively inhibit the formation of lithium dendrites.

[0033] 3. Flame retardant and thermal stability: By compounding hexaphenoxy cyclotriphosphazene (HPCTP) and hexachlorocyclotriphosphazene (HCCP), the limiting oxygen index of the material reaches 29%, and it self-extinguishes in high temperature environments, improving the safety of carbon fiber batteries. The thermal decomposition temperature of the material reaches 360°C, which is suitable for use in high temperature resistant scenes such as drones.

[0034] 4. Structure-energy storage integrated design: The high-pressure RTM process is used to achieve the overall curing and molding of carbon fiber preforms and polymer electrolytes to form an integrated carbon fiber battery structure. This design reduces the interface impedance, enhances the ion transmission efficiency, can better support the lithium ion migration inside the battery, and effectively improves the electrochemical performance. For carbon fiber fuselage equipment such as drones, replacing traditional structural materials with carbon fiber batteries with energy storage functions not only improves the energy density of the equipment, but also achieves lightweight, significantly broadening the application prospects of this technology. DETAILED DESCRIPTION

[0035] The present invention provides an epoxy resin polymer electrolyte, which is made of the following raw materials in parts by weight:

[0036] 10-50 parts of base material, 3-25 parts of toughening material, 1-10 parts of short-chain curing agent, 1-10 parts of long-chain curing agent, 1-8 parts of flame retardant reinforcing material and 2-15 parts of lithium trifluoromethylsulfonyl imide, preferably 20-40 parts of base material, 8-20 parts of toughening material, 2-8 parts of short-chain curing agent, 2-8 parts of long-chain curing agent, 2-7 parts of flame retardant reinforcing material and 4-13 parts of lithium trifluoromethylsulfonyl imide, more preferably 25-35 parts of base material, 12-16 parts of toughening material, 4-6 parts of short-chain curing agent, 4-6 parts of long-chain curing agent, 3-6 parts of flame retardant reinforcing material and 6-10 parts of lithium trifluoromethylsulfonyl imide, more preferably 28-30 parts of base material, 15 parts of toughening material, 5 parts of short-chain curing agent, 5 parts of long-chain curing agent, 4-5 parts of flame retardant reinforcing material and 8 parts of lithium trifluoromethylsulfonyl imide;

[0037] The matrix material is composed of polyurethane modified epoxy resin and polypropylene glycol diglycidyl ether;

[0038] The toughening material is composed of carboxyl-terminated nitrile rubber and succinonitrile;

[0039] The short-chain curing agent consists of polyetheramine D230 and polyetheramine D400;

[0040] The long-chain curing agent consists of polyetheramine D2000 and polyetheramine T5000;

[0041] The flame retardant reinforcement material consists of hexaphenoxy cyclotriphosphazene and hexachlorocyclotriphosphazene.

[0042] Preferably, the mass ratio of the polyurethane-modified epoxy resin to polypropylene glycol diglycidyl ether in the matrix material is 0.5 to 2:1, preferably 0.8 to 1.8:1, more preferably 1 to 1.5:1, and more preferably 1.2:1.

[0043] In the present invention, the mass ratio of the carboxyl-terminated nitrile rubber to succinonitrile in the toughening material is 0.5 to 2:1, preferably 0.8 to 1.8:1, more preferably 1 to 1.5:1, and more preferably 1.2:1.

[0044] In the present invention, the mass ratio of polyetheramine D230 to polyetheramine D400 in the short-chain curing agent is 0.5 to 2:1, preferably 0.8 to 1.8:1, more preferably 1 to 1.5:1, and more preferably 1.2:1.

[0045] In the present invention, the mass ratio of polyetheramine D2000 to polyetheramine T5000 in the long-chain curing agent is 0.5-2:1, preferably 0.8-1.8:1, more preferably 1-1.5:1, and more preferably 1.2:1.

[0046] In the present invention, the mass ratio of hexaphenoxy cyclotriphosphazene to hexachlorocyclotriphosphazene in the flame retardant reinforcement material is 1:1, and the two can significantly improve the flame retardant properties of the material.

[0047] The present invention provides a method for preparing the above epoxy resin polymer electrolyte, comprising the following steps:

[0048] The epoxy resin polymer electrolyte is obtained by mixing a matrix material, a toughening material, a short-chain curing agent, a long-chain curing agent, a flame retardant reinforcing material and lithium trifluoromethylsulfonyl imide.

[0049] The present invention also provides a carbon fiber battery, and the preparation method of the carbon fiber battery comprises the following steps:

[0050] 1) coating the positive electrode active material slurry and the negative electrode active material slurry on the nickel-plated carbon fiber respectively, and drying and curing them in sequence to obtain the carbon fiber battery positive electrode and the carbon fiber battery negative electrode;

[0051] 2) mixing the ultra-thin epoxy resin glass fiber prepreg with the shrinkable filler, and sequentially curing and heating at high temperature to obtain a diaphragm layer;

[0052] 3) Assembling a carbon fiber battery positive electrode, a carbon fiber battery negative electrode, a separator layer and an epoxy resin polymer electrolyte to obtain a carbon fiber battery;

[0053] The epoxy resin polymer electrolyte is an epoxy resin polymer electrolyte.

[0054] In the present invention, the method for preparing the nickel-plated carbon fiber comprises the following steps:

[0055] Cleaning: Clean the carbon fiber with deionized water or anhydrous ethanol in an ultrasonic cleaner for 5 to 20 minutes to remove dust, oil and some surface size agents; take out the carbon fiber and rinse it with deionized water until there is basically no obvious impurities.

[0056] Alkali treatment: immerse the carbon fiber in a 5-10% NaOH solution for 10-30 minutes, and control the temperature to 40-60°C; rinse with deionized water until the pH of the solution is close to neutral;

[0057] Acid treatment: Immerse the carbon fiber in a 5-10% HNO3 or HCl solution for 10-30 minutes at room temperature or 40-60°C; rinse thoroughly with deionized water until the pH value is neutral;

[0058] It can effectively remove residual impurities on the surface of carbon fiber and moderately etch the fiber surface, providing activation conditions for subsequent chemical nickel plating;

[0059] Sensitization: Immerse the treated carbon fiber in a SnCl2 solution (concentration 5-10 g / L, solution pH 1-2, using hydrochloric acid to maintain an acidic environment) for 5-10 minutes at room temperature to deposit Sn on the surface of the carbon fiber. 2+ ions, making the fiber surface more susceptible to adsorption of palladium ions in the subsequent activation step;

[0060] Activation: Place the sensitized carbon fiber in a PdCl2 solution (typical concentration 0.5-1.0 g / L, pH about 1-2) and soak at room temperature for 5-10 minutes; through the reduction reaction, the palladium ions are partially reduced on the surface of the carbon fiber to form palladium nuclei (Pd), which will serve as catalytic active sites in the chemical plating process;

[0061] Chemical nickel plating: nickel sulfate or nickel chloride is used to prepare a solution with a concentration of, and a reducing agent (sodium hypophosphite), a complexing agent (lactic acid, citric acid, acetic acid), a buffer (ammonium acetate / acetic acid), and a pH adjuster (ammonia water, hydrochloric acid) are added to prepare a chemical plating solution, wherein the concentration of the nickel salt is 10-20 g / L, the concentration of the reducing agent is, and the pH value of the system is 4.5-5.0;

[0062] The activated carbon fiber is immersed in the prepared plating solution; the plating solution temperature is controlled at 70-90°C, and the solution is stirred or gas stirred to maintain uniformity; the nickel plating time is 20-60 minutes, which can be appropriately extended according to the required nickel layer thickness; the nickel ions are reduced and deposited on the surface of the carbon fiber by sodium hypophosphite to form a uniform and dense nickel plating layer;

[0063] Post-treatment: Take out the nickel-plated carbon fiber, rinse it with deionized water, and dry it at 60-80° C. for 30-60 min to remove residual moisture, so as to obtain a nickel-plated carbon fiber with uniform surface and good bonding strength.

[0064] In the present invention, the positive electrode active material in step 1) is lithium iron phosphate and / or lithium nickel cobalt manganese oxide; the positive and negative electrode active materials are attached to the surface of the nickel-plated carbon fiber, further improving the current collection effect and interface conductivity of the electrode.

[0065] In the present invention, the negative electrode active material in step 1) is one or more of carbon-based materials or metallic lithium.

[0066] In the present invention, the method for preparing the positive electrode active material slurry and the negative electrode active material slurry comprises the following steps:

[0067] The positive electrode active material and the negative electrode active material are mixed with a solvent, a conductive agent and a binder to form a slurry.

[0068] In the present invention, the curing temperature in step 1) is 80-130° C., preferably 90-120° C., and more preferably 100-110° C.; the curing time is 3-6 hours, preferably 3.5-5.5 hours, and more preferably 4-5 hours.

[0069] In the present invention, the nickel-plated carbon fiber can not only be used as a structural reinforcement material, but also has good conductivity, so that it also has the function of an electrode current collector, reducing the demand for traditional metal foil and achieving a lightweight effect.

[0070] In the present invention, the shrinkable filler in step 2) comprises one or more of polystyrene foam powder, polylactic acid powder, polycaprolactone powder and phenolic foam powder.

[0071] In the present invention, the curing temperature in step 2) is 80-130° C., preferably 90-120° C., and more preferably 100-110° C.; the curing time is 3-6 hours, preferably 3.5-5.5 hours, and more preferably 4-5 hours.

[0072] In the present invention, the high temperature heating in step 2) is performed at a temperature of 140 to 180° C., preferably 150 to 170° C., and more preferably 155 to 160° C.; and the heating time is 1 to 3 hours, preferably 1.5 to 2.5 hours, and more preferably 3 hours.

[0073] In the present invention, the resin content of the ultra-thin epoxy resin glass fiber prepreg in step 2) is less than 30wt%, preferably 15-30wt%, more preferably 18-28wt%, and more preferably 20-25wt%.

[0074] In the present invention, the shrinkable filler in step 2) is preferably EPS foam needle-shaped powder.

[0075] The shrinkable filler can shrink significantly in volume under high temperature conditions. The resin in the ultra-thin epoxy resin glass fiber prepreg is initially cured at medium temperature and then raised to a specific temperature to reduce the volume of the shrinkable filler by dozens of times, leaving tiny physical channels in the epoxy matrix to form a path that is conducive to the migration of lithium ions, thereby ensuring the mechanical stability of the material and effectively forming ion channels.

[0076] In the present invention, the curing temperature in step 3) is 80-130° C., preferably 90-120° C., and more preferably 100-110° C.; the curing time is 3-6 hours, preferably 3.5-5.5 hours, and more preferably 4-5 hours.

[0077] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0078] Example 1

[0079] (1) The polyurethane modified epoxy resin and polypropylene glycol diglycidyl ether were placed in a dry environment (60°C, 30 min) to reduce the moisture content; then 5 g of polyurethane modified epoxy resin (Taizhou Hengchuang Insulation Materials Co., Ltd., 102C-1) and 5 g of polypropylene glycol diglycidyl ether (Anhui Xinyuan Technology Co., Ltd., XY207) were mixed and stirred at 60°C and 30 rpm for 30 min until the mixture was uniformly mixed; then 2.5 g of the toughening component, carboxyl-terminated nitrile rubber (Zeon Chemicals, CTBN 1300X8) and 2.5 g of succinonitrile were added and stirred for 15 min, and then 1 g of polyetheramine D230, 1 g of polyetheramine D400, 1 g of polyetheramine D2000 and 1 g of polyetheramine T5000 were added and stirred for 30 minutes to fully mix the raw materials; 1 g of HPCTP and 1 g of HCCP was stirred for 20 min, and finally 4 g LiTFSI was added and stirred for 30 min to obtain the epoxy resin polymer electrolyte.

[0080] (2) Nickel-plated carbon fiber is used as the current collector layer.

[0081] An ultra-thin epoxy resin glass fiber prepreg with a resin content of less than 30% (Shenzhen Langbowan Advanced Materials Co., Ltd., Y01-1 ultra-thin epoxy resin glass fiber prepreg) was used as the separator layer between the positive and negative electrodes.

[0082] A large amount of needle-shaped filler EPS foam needle-shaped micropowder, which can shrink significantly under high temperature conditions, is added to the resin matrix in the epoxy resin glass fiber prepreg. The resin matrix is ​​initially cured at 80°C for 1 hour, and then raised to 160°C and kept warm for 2 hours, which causes the volume of the filler to shrink by dozens of times, leaving tiny physical channels in the epoxy matrix, forming a path that is conducive to the migration of lithium ions. This process not only ensures the mechanical stability of the material, but also effectively forms ion channels.

[0083] The positive and negative active materials lithium iron phosphate are attached to the surface of the nickel-plated carbon fiber layer to improve the current collection effect and interface conductivity of the electrode. Specifically, 1g lithium iron phosphate, 0.1g acetylene black, 0.1g polyvinylidene fluoride and 5mL N-methylpyrrolidone are mixed into a slurry and then coated on the surface of the nickel-plated carbon fiber. The coating amount of lithium iron phosphate is 0.1g / cm 2 .

[0084] The prefabricated current collector, electrode material layer and diaphragm layer are laminated and combined in the designed order, and then finally cured by high-pressure RTM process: first, the mold is preheated to 70°C, and the epoxy resin polymer electrolyte prepared in step (1) is injected at a pressure of 0.5 MPa. After preliminary curing at 80°C for 30 minutes, it is kept at 160°C for 2 hours. The pressure parameter of the system during the curing process is 1.0 MPa. After the insulation is completed, the temperature is cooled to room temperature at a rate of 5°C / min to avoid internal stress concentration caused by rapid cooling, and the pressure is reduced to normal pressure in stages. The mold is opened and the molded part is taken out to obtain a structure-energy storage integrated molding to obtain a structure-energy storage integrated carbon fiber battery.

[0085] The electrochemical performance and flame retardant performance of the structure-energy storage integrated carbon fiber battery prepared in this embodiment were tested, and the test results are as follows:

[0086] A high initial discharge capacity of 160 mAh / g was achieved at a rate of 0.1C, and the capacity retention rate was 95.2% after 100 cycles.

[0087] The epoxy resin polymer electrolyte was made into a film (15mm×150mm) with a thickness of 50μm, and tested using a universal material testing machine (Instron). Before testing, the sample was placed in a room temperature environment for 24h (ambient temperature was 23℃, humidity was 54%), and the material was stretched at a tensile rate of 5mm / min. The test results are as follows: the tensile strength of the material reached 15MPa, and the elongation at break was 56.2%. It has both toughness and strength, so that the carbon fiber composite material has stable mechanical support while bearing the structure and energy storage function at the same time, adapts to large volume changes, and effectively inhibits the formation of lithium dendrites;

[0088] The limiting oxygen index is 29%, and it self-extinguishes in high temperature environments, improving the safety of carbon fiber batteries; the thermal decomposition temperature of the material reaches 360°C, making it suitable for high temperature scenarios.

[0089] Example 2

[0090] The only difference compared with Example 1 is that the added amount of the carboxyl-terminated nitrile rubber is 2 g and the added amount of succinonitrile is 3 g. The other components and preparation steps are the same as Example 1.

[0091] Example 3

[0092] The only difference compared with Example 1 is that the added amount of polyurethane modified epoxy resin is 6 g and the added amount of polypropylene glycol diglycidyl ether is 4 g. The other components and preparation steps are the same as Example 1.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength porous polymer electrolyte membrane, characterized in that: The steps include: 1) mixing polyvinylidene fluoride, polyacrylonitrile, a pore-forming agent, a filler and a solvent to obtain a mixed solution; 2) electrospinning the mixed solution to obtain a nanofiber membrane; 3) The obtained nanofiber membrane is immersed in a pore-forming agent remover, taken out, and then activated and heat-treated in sequence to obtain a porous polymer electrolyte membrane.

2. The method for preparing a high-strength porous polymer electrolyte membrane according to claim 1, characterized in that: Step 1) The pore-forming agent is polyethylene glycol and / or nano-silicon dioxide; the filler is nano-silicon dioxide, alumina or graphene; and the solvent is N,N-dimethylformamide or N-methylpyrrolidone.

3. The method for preparing a high-strength porous polymer electrolyte membrane according to claim 2, characterized in that: In the step 1), the mass ratio of polyvinylidene fluoride to polyacrylonitrile is 1-2:2-4; The mass ratio of polyvinylidene fluoride to polyacrylonitrile, pore-forming agent, filler and solvent is 10-20:5-15:3-7:

100.

4. A method for preparing a high-strength porous polymer electrolyte membrane according to claim 2 or 3, characterized in that: In the step 1), the mixing is ultrasonic mixing, the power of the ultrasonic mixing is 200-500W, the time of the ultrasonic mixing is 20-60min, and the temperature of the ultrasonic mixing is 20-40°C.

5. The method for preparing a high-strength porous polymer electrolyte membrane according to claim 4, characterized in that: In the step 2), the voltage of electrospinning is 15-20 kV, the speed of electrospinning is 0.5-1 mL / h, and the working distance of electrospinning is 12-20 cm.

6. The method for preparing a high-strength porous polymer electrolyte membrane according to claim 5, characterized in that: In the step 3), the pore-forming agent remover is ethanol and / or water; The soaking temperature is 40-60° C., and the soaking time is 30-120 min.

7. A method for preparing a high-strength porous polymer electrolyte membrane according to claim 3 or 5, characterized in that: In the step 3), activation is performed by immersing the electrolyte in an electrolyte for 1 to 4 hours; The electrolyte comprises a lithium-containing compound and a solvent, wherein the lithium-containing compound is lithium hexafluorophosphate or lithium bis(trifluoromethylsulfonyl)imide, and the solvent is one or more of polycarbonate, ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate; and the concentration of the electrolyte is 0.8-1.2 mol / L.

8. The method for preparing a high-strength porous polymer electrolyte membrane according to claim 7, characterized in that: In the step 3), the heat treatment temperature is 100-120° C., and the heat treatment time is 1-2 hours.

9. A porous polymer electrolyte membrane obtained by the method for preparing a high-strength porous polymer electrolyte membrane according to any one of claims 1 to 8.

10. Use of the porous polymer electrolyte membrane according to claim 9 in a battery.