High-performance diaphragm slurry and preparation method of diaphragm thereof

Abstract

The invention discloses high-performance diaphragm slurry and a preparation method of a diaphragm thereof, and belongs to the technical field of diaphragms. The diaphragm slurry comprises the following components: bio-based particles, inorganic ceramic fibers, hot-melt microspheres, a dispersing agent, a wetting agent, a binder and a solvent. The diaphragm is prepared by using the diaphragm slurry mixing and coating process, coating of a nanoscale coating can be realized, and the obtained diaphragm is light in weight, has relatively good electrolyte affinity, liquid absorption and retention rate and electrolyte infiltration rate, still has certain strength at a high temperature, is relatively small in thermal shrinkage deformation rate, and has relatively high diaphragm rupture temperature; the battery internal resistance can be effectively reduced, and the battery electrical performance and safety performance are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of diaphragms, and particularly relates to a preparation method of a high-performance diaphragm slurry and a diaphragm thereof. Background Art

[0002] Lithium-ion batteries are batteries widely used in fields such as mobile devices, electric vehicles, and energy storage systems. They have advantages such as high energy density, long cycle life, low self-discharge rate, and environmental friendliness, so they have become one of the common types of rechargeable batteries. The main components of lithium-ion batteries include a positive electrode, a negative electrode, an electrolyte, and a diaphragm. The diaphragm is one of the important components of lithium-ion batteries. The performance of the diaphragm affects the electrical performance and safety performance of the battery. Therefore, higher requirements are put forward for the performance of the diaphragm.

[0003] In recent years, with the large-scale application of lithium-ion batteries, the performance and safety of the batteries have become the focus of user attention. At present, in battery design, polyolefin materials with lower cost and more mature processes are mostly used as the base film, and a heat-resistant ceramic layer is coated to improve the heat resistance and wettability of the diaphragm. However, this type of diaphragm coating has a large thickness, which will affect the internal resistance and performance of the battery, and the high-temperature heat resistance of the diaphragm is not good, so the thermal safety performance of the battery cannot be guaranteed. In order to improve the comprehensive performance of the battery, it is necessary to design a high-performance diaphragm slurry and a diaphragm thereof. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of a high-performance diaphragm slurry and a diaphragm thereof, so as to solve the problem that the high-temperature heat resistance of the diaphragm is not good and the thermal safety performance of the battery cannot be guaranteed.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] In a first aspect, the present invention provides a high-performance diaphragm slurry, which includes the following raw material components: bio-based particles, inorganic ceramic fibers, hot-melt microspheres, dispersants, wetting agents, binders, and solvents;

[0007] The mass ratio of the bio-based particles, inorganic ceramic fibers, hot-melt microspheres, dispersants, wetting agents, binders, and solvents is 1-10%: 10-20%: 1-5%: 1-5%: 0.1-0.5%: 5-10%: 70-80%.

[0008] Further, the bio-based particles are one or more of furanyl polyamide particles, furanyl polyimide particles, and furan polyester particles, the particle size range is 0.01-0.1 μm, and the thermal decomposition temperature > 400 °C.

[0009] Further, the inorganic ceramic fiber is one or more of alumina, boehmite, silica, magnesia, lithium titanium aluminum phosphate, lithium lanthanum zirconium oxide, and lithium lanthanum titanium oxide, with a diameter range of 0.1 - 0.5 μm and a length of 1 - 5 μm.

[0010] Further, the type of the hot-melt microspheres is one of polyethylene and polypropylene, with a particle size of 0.02 - 0.2 μm and a melting point of 90 - 130 °C.

[0011] Further, the dispersant is one or more of polyester ammonium salts, quaternary ammonium salts, polyurethanes, and polyesters.

[0012] Further, the wetting agent is one or more of polyethers, fatty alcohols, and fatty acid esters.

[0013] Further, the binder is one or more of polyimides, polyamides, polyacrylates, and polyacrylic acids, with a glass transition temperature > 180 °C.

[0014] Further, the solvent is deionized water.

[0015] Further, the slurry mixing process of the separator slurry is as follows: Mix the bio-based particles, inorganic ceramic fibers, dispersant, and deionized water in proportion, disperse them by high-speed stirring, and then add the hot-melt microsphere emulsion, wetting agent, and binder and disperse them at low speed to form the separator slurry.

[0016] In a second aspect, the present invention provides a method for preparing a separator of a high-performance separator slurry. The separator is prepared using the above high-performance separator slurry, and the method includes the following steps:

[0017] Coat the separator slurry on a substrate through a coating process to form a separator; the coating process is one of gravure roll coating and extrusion; the thickness of the coating is ≤ 2 μm; the substrate is one of a PE-based film, a PP-based film, a PE / PP composite film, or other types of substrate films.

[0018] The beneficial effects of the present invention:

[0019] (1) The present invention discloses a high-performance separator slurry and a separator. The slurry comprises the following raw material components: bio-based particles, inorganic ceramic fibers, hot-melt microspheres, a dispersant, a wetting agent, a binder, and a solvent; the bio-based particles are high-heat-resistant nanoparticles with a bio-based functional group furan ring structure, and their structure with a conjugated π-electron system can have good affinity with the electrolyte in the battery; at the same time, hot-melt microspheres with a better heat-induced deformation rate are selected, and the bio-based particles and the hot-melt microspheres can better fill the gaps of the inorganic ceramic fibers; a binder with a higher glass transition temperature is used, and together with the nano-inorganic ceramic fibers, it forms a functional layer with a "point-line-plane" structure, and at the same time, it matches the slurry coating process to form an ultra-thin coating and coat it on a substrate to make a separator.

[0020] (2) The separator prepared by the present invention has good ionic conductivity. When the internal temperature of the battery > 90 °C, the hot-melt microspheres in the coating of the separator deform, quickly melt as the temperature rises, and closely fit with the bio-based particles and the inorganic ceramic fibers, which can timely close the ion transport channels, form an isolation layer with strength, quickly inhibit the spread of heat, and ensure the safety performance of the battery; the battery using this separator can effectively improve the battery electrical performance, improve the battery safety performance, and greatly improve the comprehensive performance of the lithium-ion battery. Specific embodiments

[0021] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0022] Example 1

[0023] This example provides a separator, which is prepared by the following method:

[0024] (1) Prepare the separator slurry:

[0025] Select furan-based polyamide particles with a particle size of 0.05 μm, alumina ceramic fibers with a diameter of 0.1 μm and a length of about 1 μm, polyester ammonium salt dispersant HY609 and deionized water in a mass ratio of 5%: 10%: 1.8%: 75%; use a high-speed disperser to rotate at 2000 rpm and revolve at 20 rpm, and stir for 2 h to form a primary mixed slurry. Then, select a polyethylene microsphere emulsion with a particle size of 0.1 μm, polyether wetting agent 20990, and polyimide binder YJ22, and add them to the primary mixed slurry in a mass ratio of 3%: 0.2%: 5%. Use a disperser to rotate at 600 rpm and revolve at 20 rpm, and stir for 1 h to obtain the separator slurry;

[0026] (2) Preparation of separator:

[0027] Select a 7-μm PE base film, and use the gravure roll coating process to apply a 2-μm single-sided coating on the base film to obtain the separator.

[0028] Example 2

[0029] This example provides a separator, which is prepared by the following method:

[0030] (1) Preparation of separator slurry:

[0031] Select furan polyester particles with a particle size of 0.1 μm, boehmite ceramic fibers with a diameter of 0.2 μm and a length of about 4 μm, polyurethane dispersant WCA80 and deionized water in a mass ratio of 6%: 10%: 2.7%: 71%, and use a high-speed disperser to rotate at 2500 rpm self-rotation and 30 rpm revolution for 3 hours to form a preliminary slurry mixture. Then, select polypropylene microsphere emulsion with a particle size of 0.2 μm, fatty alcohol wetting agent BL10, and polyamide binder JH5140, and add them to the preliminary slurry mixture in a mass ratio of 4%: 0.3%: 6%. Use a disperser to rotate at 500 rpm self-rotation and 30 rpm revolution, and stir for 1 hour to obtain the separator slurry;

[0032] (2) Preparation of separator:

[0033] Select a 9-μm PE base film, and use the gravure roll coating process to apply a 1-μm coating on both sides of the base film to obtain the separator.

[0034] Example 3

[0035] This example provides a separator, which is prepared by the following method:

[0036] (1) Preparation of separator slurry:

[0037] Select furan-based polyimide particles with a particle size of 0.06 μm, lithium titanium aluminum phosphate ceramic fibers with a diameter of 0.3 μm and a length of about 3 μm, quaternary ammonium salt dispersant XW330 and deionized water in a mass ratio of 3%: 15%: 4.5%: 70%, and use a high-speed disperser to rotate at 1800 rpm self-rotation and 25 rpm revolution for 2.5 hours to form a preliminary slurry mixture. Then, select polypropylene microsphere emulsion with a particle size of 0.15 μm, fatty acid ester wetting agent S60, and polyacrylic acid binder GR506, and add them to the preliminary slurry mixture in a mass ratio of 2%: 0.5%: 5%. Use a disperser to rotate at 400 rpm self-rotation and 25 rpm revolution, and stir for 2 hours to obtain the separator slurry;

[0038] (2) Preparation of separator:

[0039] Select a 9μm PE base film, and use the gravure roll coating process to apply a 2μm single-sided coating of the separator slurry on the base film to obtain the separator.

[0040] Example 4

[0041] (1) Prepare the separator slurry:

[0042] Select furan polyester particles with a particle size of 0.02μm, silica ceramic fibers with a diameter of 0.3μm and a length of about 2μm, polyester ammonium salt dispersant HY609 and deionized water in a mass ratio of 6%:11%:2.6%:70%. Use a high-speed disperser to rotate at 2400rpm and revolve at 30rpm for 2.5h to form a preliminary slurry mixture. Then select a polyethylene microsphere emulsion with a particle size of 0.04μm, polyether wetting agent 20990, and polyamide binder JH5140, and add them to the preliminary slurry mixture in a mass ratio of 4%:0.4%:6%. Use a disperser to rotate at 600rpm and revolve at 30rpm for 1.5h to obtain the separator slurry;

[0043] (2) Prepare the separator:

[0044] Select a 12μm PP base film, and use the gravure roll coating process to apply a 1μm double-sided coating of the separator slurry on the base film to obtain the separator.

[0045] Example 5

[0046] (1) Prepare the separator slurry:

[0047] Select furan-based polyimide particles with a particle size of 0.04μm, magnesium oxide ceramic fibers with a diameter of 0.5μm and a length of about 5μm, polyurethane dispersant WCA80 and deionized water in a mass ratio of 4%:12%:3.5%:72%. Use a high-speed disperser to rotate at 2100rpm and revolve at 35rpm for 3h to form a preliminary slurry mixture. Then select a polypropylene microsphere emulsion with a particle size of 0.08μm, fatty alcohol wetting agent BL10, and polyimide binder YJ22, and add them to the preliminary slurry mixture in a mass ratio of 3%:0.5%:5%. Use a disperser to rotate at 650rpm and revolve at 25rpm for 1h to obtain the separator slurry;

[0048] (2) Prepare the separator:

[0049] Select a 15μm PE / PP composite base film, and use the gravure roll coating process to apply a 1.5μm single-sided coating of the separator slurry on the base film to obtain the separator.

[0050] Comparative Example 1

[0051] This comparative example provides a separator, which is prepared by the following method:

[0052] (1) Preparation of separator slurry:

[0053] Select furan-based polyamide particles with a particle size of 0.05 μm, alumina ceramic fibers with a diameter of 0.1 μm and a length of about 1 μm, polyester ammonium salt dispersant HY609 and deionized water in a mass ratio of 5%: 10%: 1.8%: 78%. Use a high-speed disperser to rotate at 2000 rpm and revolve at 20 rpm for 2 hours to form a preliminary mixed slurry. Then select polyether wetting agent 20990 and polyimide binder YJ22, and add them to the preliminary mixed slurry in a mass ratio of 0.2%: 5%. Use the disperser to rotate at 600 rpm and revolve at 20 rpm, and stir for 1 hour to obtain the separator slurry;

[0054] (2) Preparation of separator:

[0055] Select a 7-μm PE-based film, and use the gravure roll coating process to apply a 2-μm single-sided coating of the separator slurry on the base film to obtain the separator.

[0056] Comparative Example 2

[0057] This comparative example provides a separator, which is as follows:

[0058] A commercially available 7-μm PE-based film with a 2-μm alumina ceramic coating on one side.

[0059] Select the same battery cell materials and manufacturing process, and fabricate the separators in Example 1, Example 4, Example 5, Comparative Example 1 and Comparative Example 2 into 55 Ah square wound lithium iron phosphate batteries, and conduct battery performance tests.

[0060] Comparative Example 3

[0061] This comparative example provides a separator, which is prepared by the following method:

[0062] (1) Preparation of separator slurry:

[0063] Select boehmite ceramic fibers with a diameter of 0.2 μm and a length of about 4 μm, polyurethane dispersant WCA80 and deionized water in a mass ratio of 10%: 2.7%: 77%. Use a high-speed disperser to rotate at 2500 rpm and revolve at 30 rpm for 3 hours to form a preliminary mixed slurry. Then select polypropylene microsphere emulsion with a particle size of 0.2 μm, fatty alcohol wetting agent BL10, and polyamide binder JH5140, and add them to the preliminary mixed slurry in a mass ratio of 4%: 0.3%: 6%. Use the disperser to rotate at 500 rpm and revolve at 30 rpm, and stir for 1 hour to obtain the separator slurry;

[0064] (2) Preparation of separator:

[0065] A 9-μm PE base film was selected, and the separator slurry was coated on both sides of the base film with a coating thickness of 1 μm each using a gravure roll coating process to obtain the separator.

[0066] Comparative Example 4

[0067] This comparative example provides a separator, specifically as follows:

[0068] A commercially available 9-μm PE base film was coated with a 1-μm boehmite ceramic coating on both sides.

[0069] The same electrode materials and manufacturing processes were selected, and the separators in Example 2, Comparative Example 3, and Comparative Example 4 were fabricated into 50-Ah square wound nickel-cobalt-manganese ternary system batteries for battery performance testing.

[0070] Comparative Example 5

[0071] This comparative example provides a separator, which is prepared by the following method:

[0072] (1) Preparation of the separator slurry:

[0073] Furanyl polyimide particles with a particle size of 0.06 μm, quaternary ammonium salt dispersant XW330, and deionized water were selected and mixed at a mass ratio of 3%: 4.5%: 85%. A high-speed disperser was used to rotate at 1800 rpm for self-rotation and 25 rpm for revolution, and stirred for 2.5 h to form a preliminary mixed slurry. Then, polypropylene microsphere emulsion with a particle size of 0.15 μm, fatty acid ester wetting agent S60, and polyacrylic acid binder GR506 were added to the preliminary mixed slurry at a mass ratio of 2%: 0.5%: 5%. The disperser was used to rotate at 400 rpm for self-rotation and 25 rpm for revolution, and stirred for 2 h to obtain the separator slurry.

[0074] (2) Preparation of the separator:

[0075] A 9-μm PE base film was selected, and the separator slurry was coated on one side of the base film with a coating thickness of 2 μm using a gravure roll coating process to obtain the separator.

[0076] Comparative Example 6

[0077] This comparative example provides a separator, specifically as follows:

[0078] A commercially available 9-μm PE base film was coated with a 2-μm lithium titanium aluminum phosphate ceramic coating on one side.

[0079] The same electrode materials and manufacturing processes were selected, and the separators in Example 3, Comparative Example 5, and Comparative Example 6 were fabricated into 15-Ah cylindrical wound lithium iron phosphate system batteries for battery performance testing.

[0080] The diaphragms prepared in the above Examples 1 - 5 and Comparative Examples 1 - 6 were respectively tested for liquid absorption and retention rate, electrolyte wetting area, ionic conductivity, thermal shrinkage rate at 150°C for 1 h, and membrane rupture temperature according to the following test conditions; the batteries prepared in Examples 1 - 5 and Comparative Examples 1 - 6 were respectively tested for internal resistance, 0.5C cycle capacity retention rate at 45°C, and thermal runaway performance according to the following test conditions.

[0081] Liquid absorption and retention rate test: Cut 3 pieces of each test diaphragm into diaphragms of 100 mm × 100 mm, weigh them respectively and make marks as m1. Clamp the diaphragm with two layers of lint - free cloth, wind it into a barrel shape, tie it with a rope, and immerse it in a plastic beaker filled with electrolyte for 1 h. The electrolyte type is a 1.0 mol / L lithium hexafluorophosphate electrolyte with a volume ratio of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate of 1:1:1; then take the diaphragm out of the beaker, quickly wipe the electrolyte on the surface of the diaphragm with absorbent paper and weigh it as m2, and weigh the wiped diaphragm after placing it in a fume hood for 1 h as m3. The liquid absorption rate is calculated according to the formula (m2 - m1) / m1×100%, and the liquid retention rate is calculated according to the formula (m3 - m1) / m1×100%. Take the average value of 3 test results as the liquid absorption rate and liquid retention rate test values.

[0082] Electrolyte wetting area: Select an electrolyte type of 1.0 mol / L lithium hexafluorophosphate electrolyte with a volume ratio of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate of 1:1:1. Wear rubber gloves, use a ceramic scissor / cutter to take a sample of the diaphragm, with a sampling size of 100×250 mm. Use clips to fix the diaphragm in the air on a rectangular tray, ensuring that the membrane surface has no collapse or wrinkles. Use a 25 μL pipette to sample the electrolyte, and drop the electrolyte vertically 10 mm away from the membrane surface. Use a stopwatch to time. After 1 min, use a film ruler to detect the electrolyte wetting length in the MD / TD direction and estimate the wetting area at the same time.

[0083] Ionic conductivity test: Cut the separator and place it in an electrolyte of 1.0 mol / L lithium hexafluorophosphate with a volume ratio of ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate of 1:1:1. Keep it sealed and soaked for 2 h. Inject the electrolyte into the resistance test mold, place 1 layer of separator in sequence, measure its AC impedance resistance, then place another 1 layer and measure its AC impedance resistance until 4 layers are placed, and measure four AC impedance resistance values respectively. During the test, ensure that the electrolyte in the resistance test mold can completely soak the placed separator. Use the number of separator layers as the abscissa and the resistance as the ordinate to plot a curve, and calculate the slope and linear fitting degree of the curve. When the linear fitting degree is greater than 0.99, calculate the ionic conductivity according to the formulas R = k×1 and σ = d / R×S. When the linear fitting degree is less than 0.99, retest. In the formulas: R - the resistance of 1 layer of separator, unit ohm; k - the slope of the curve when the fitting degree is greater than 0.99; σ - ionic conductivity, unit Siemens per centimeter; d - the thickness of 1 layer of separator, unit micrometer; R - the resistance value of 1 layer of separator, unit ohm; S - the separator test area, unit square centimeter.

[0084] Thermal shrinkage rate test: Cut the test separator into 3 pieces of 100 mm×100 mm. Measure the longitudinal and transverse lengths of each piece respectively. Use a forced-air constant temperature oven with an accuracy of ±1°C. Place the stainless steel plate and two quantitative filter papers in the middle of the oven. After placing the separator between the two filter papers, close the oven door and keep it at 150°C for 1 h. After heating, take out the separator. After the separator returns to room temperature, measure the longitudinal and transverse lengths again. Calculate the shrinkage rate according to the formula ΔL = (L0 - L1) / L0×100%. Take the average of 3 test results as the thermal shrinkage rate of the separator. In the formula: ΔL - thermal shrinkage rate, unit %; L0 - the length before heating, unit mm; L1 - the length after heating, unit mm.

[0085] Film breakage temperature test: Cut the separator into strips with a length of 30 cm and a width of 2 cm. Use a thermomechanical analyzer to start the test from room temperature at a tensile force of 0.03 N and a heating rate of 5°C / min until the separator breaks, and record the film breakage temperature value as the film breakage temperature.

[0086] Internal resistance test: Use a resistance tester to test the trial-produced battery after formation, and record the internal resistance value of the battery.

[0087] Cyclic capacity retention rate test: Place the battery in an incubator at 45°C and charge it at a constant current of 1C until the termination voltage, then switch to constant voltage charging. Stop charging when the charging current drops to 0.05C. After standing for 30 minutes, discharge it at a current of 0.5C. After standing for 30 minutes, continue charging according to the above method, and then discharge it at a current of 0.5C after standing for 30 minutes. Continuously cycle 500 times according to the above charge-discharge method, and calculate the capacity retention rate by dividing the measured battery discharge capacity by the initial capacity and multiplying by 100%; for the diaphragm batteries of Example 1, Example 3, Example 4, Example 5, Comparative Example 1, Comparative Example 2, Comparative Example 5, and Comparative Example 6, the charge and discharge cut-off voltages are 3.65V and 3.2V, and for the diaphragm batteries of Example 2, Comparative Example 3, and Comparative Example 4, the charge and discharge cut-off voltages are 4.2V and 3.6V.

[0088] Thermal runaway test: Use an adiabatic accelerating calorimeter to perform a stepwise temperature increase test on the battery starting from 50°C. After each 3°C temperature increase, observe it statically for 1 hour and then continue to increase the temperature until 300°C. Record the state of the battery at the end of the test.

[0089] The test data for each item is shown in Table 1.

[0090] Table 1

[0091]

[0092]

[0093] As can be seen from Table 1, the test results show that the diaphragms in Examples 1 - 5 all have relatively high liquid absorption and retention rates, electrolyte infiltration areas, ionic conductivities, and high-temperature resistance; the batteries prepared in Examples 1 - 5 have relatively low internal resistances, the batteries have better cycle lives and higher thermal stability and safety performances, and the comprehensive performance of the batteries is better.

[0094] Compared with Example 1, in Comparative Example 1, polyethylene microsphere emulsion was not used in the diaphragm slurry, and the obtained diaphragm performance and battery performance were poor; compared with Example 2, in Comparative Example 3, furan polyester particles were not used in the diaphragm slurry, and the obtained diaphragm performance and battery performance were poor; compared with Example 3, in Comparative Example 5, lithium titanium aluminum phosphate ceramic fibers were not used in the diaphragm slurry, and the obtained diaphragm performance and battery performance were also poor; for Comparative Example 2, Comparative Example 4, and Comparative Example 6, commercially available diaphragms were used, and the obtained diaphragm performance and battery performance were also poor compared with Examples 1 - 5.

[0095] It should be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or apparatus.

[0096] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-performance diaphragm slurry, characterized in that: The raw material components include: bio-based particles, inorganic ceramic fibers, hot-melt microspheres, dispersants, wetting agents, binders and solvents; The mass ratio of the bio-based particles, inorganic ceramic fibers, hot-melt microspheres, dispersant, wetting agent, binder and solvent is 1-10%: 10-20%: 1-5%: 1-5%: 0.1-0.5%: 5-10%: 70-80%.

2. A high-performance diaphragm slurry according to claim 1, characterized in that: The bio-based particles are one or more of furan-based polyamide particles, furan-based polyimide particles and furan polyester particles, with a particle size range of 0.01-0.1 μm and a thermal decomposition temperature of more than 400° C.

3. The high-performance diaphragm slurry according to claim 1, characterized in that: The inorganic ceramic fiber is one or more of alumina, boehmite, silicon dioxide, magnesium oxide, lithium aluminum titanium phosphate, lithium lanthanum zirconium oxide and lithium lanthanum titanium oxide, with a diameter ranging from 0.1 to 0.5 μm and a length ranging from 1 to 5 μm.

4. The high-performance diaphragm slurry according to claim 1, characterized in that: The hot-melt microspheres are one of polyethylene and polypropylene, with a particle size of 0.02-0.2 μm and a melting point of 90-130° C.

5. The high-performance diaphragm slurry according to claim 1, characterized in that: The dispersant is one or more of polyester ammonium salts, quaternary ammonium salts, polyurethanes and polyesters.

6. The high-performance diaphragm slurry according to claim 1, characterized in that: The wetting agent is one or more of polyethers, fatty alcohols and fatty acid esters.

7. The high-performance diaphragm slurry according to claim 1, characterized in that: The binder is one or more of polyimide, polyamide, polyacrylate and polyacrylic acid, and has a glass transition temperature greater than 180°C.

8. The high-performance diaphragm slurry according to claim 1, characterized in that: The solvent is deionized water.

9. The high-performance diaphragm slurry according to claim 1, characterized in that: The slurry mixing process of the diaphragm slurry is as follows: bio-based particles, inorganic ceramic fibers, dispersants and deionized water are mixed together in proportion, and after high-speed stirring and dispersion, hot-melt microsphere emulsion, wetting agent and binder are added and then dispersed at a low speed to form diaphragm slurry.

10. A method for preparing a high-performance diaphragm slurry, characterized in that: The method of preparing a diaphragm using the high-performance diaphragm slurry according to any one of claims 1 to 9 comprises the following steps: The diaphragm slurry is coated on the substrate through a coating process to form a diaphragm; the coating process is one of gravure roller coating and extrusion; the thickness of the coating is ≤2μm; the substrate is a PE base film, PP base film, PE / PP composite film or one of other types of base film.

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