Preparation method for composite ceramic separator, composite ceramic separator and battery

Abstract

Disclosed are a preparation method for a composite ceramic separator, the composite ceramic separator, and a battery. The preparation method comprises the following steps: providing a suspension solution containing ceramic; applying the suspension solution to the surface of a porous base film, applying negative pressure so that the suspension solution permeates into pores of the porous base film, and drying to obtain a composite ceramic separator; wherein the particle size of the ceramic is smaller than that of the pores. The composite ceramic separator comprises the porous base film and the ceramic. The ceramic is at least formed in the pores of the porous base film. The particle size of the ceramic is smaller than that of the pores. The ceramic comprises a first inorganic ceramic, and the first inorganic ceramic is nitride inorganic ceramic. The composite ceramic separator has excellent high-temperature resistance and good interface performance, and can effectively improve the safety performance of the battery. The present preparation method allows the ceramic particles to be uniformly dispersed in the pores of the base film, and the performance of the separator is effectively improved.

Description

Preparation method of composite ceramic diaphragm, composite ceramic diaphragm and battery

[0001] This application is based on the Chinese patent application with application number 202311273775.1 and application date September 28, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0002] The invention belongs to the technical field of batteries and relates to a preparation method of a composite ceramic diaphragm, the composite ceramic diaphragm and a battery. Background Art

[0003] With the widespread adoption of new energy vehicles and portable electronic devices, people are placing higher demands on battery performance, such as high safety, high energy density, and long service life. Battery safety is particularly important. Battery explosions, spontaneous combustion, and other safety issues pose a threat to personal safety and can cause property damage. The use of liquid electrolytes is a key issue. Liquid electrolytes contain a large amount of flammable components, making them highly susceptible to explosion and combustion in the event of a collision or other impact.

[0004] Quasi-solid-state batteries, or semi-solid-state batteries, significantly improve battery safety by reducing or eliminating the use of liquid electrolytes. A key component in solid-state batteries is the solid electrolyte layer, which generally should have the following characteristics: 1. Effectively isolate the positive and negative electrodes to prevent short circuits; 2. Efficiently conduct lithium ions; and 3. Heat resistance to prevent contact between the positive and negative electrodes due to separator shrinkage at high temperatures, which could lead to safety issues.

[0005] Prior art separators typically form a ceramic layer by coating a slurry containing an electrolyte and ceramic on both sides of a base membrane. Because the ceramic is heat-resistant and the electrolyte is ion-conducting, the resulting separator exhibits heat resistance. However, the high-temperature resistance of the separator still needs to be further improved to meet the needs of practical applications. Furthermore, prior art separator preparation methods typically involve coating and then drying, which results in poor bonding between the electrolyte and ceramic on the base membrane, hindering the improvement of separator performance.

[0006] Therefore, it is necessary to provide a diaphragm and a preparation method thereof to improve the bonding of the components in the diaphragm and effectively improve its high temperature resistance.

[0007] Summary of the Invention

[0008] In view of the above problems existing in the prior art, the object of the present invention is to provide a method for preparing a composite ceramic diaphragm, a composite ceramic diaphragm and a battery.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for preparing a composite ceramic diaphragm, characterized in that the preparation method comprises the following steps:

[0011] providing a suspension comprising a ceramic;

[0012] applying the suspension to the surface of a porous base membrane, applying negative pressure to allow the suspension to penetrate into the pores of the porous base membrane, and obtaining a composite ceramic diaphragm after drying;

[0013] Wherein, the particle size of the ceramic is smaller than the pore size of the pore.

[0014] The method of the present invention applies a suspension to the surface of a porous base membrane and applies negative pressure, so that the suspension can penetrate into the pores of the porous base membrane, thereby allowing the ceramic to enter the pores. This method can evenly distribute ceramic particles in the pores of the porous base membrane. The ceramic particles in the pores can still play a stable supporting role at high temperatures. The composite ceramic separator is applied to batteries, where it can directly contact the positive and negative electrodes respectively, thereby improving the safety performance of the battery.

[0015] Compared to directly immersing the porous base membrane in a suspension containing ceramic particles to allow the ceramic particles to enter the pores, the method of the present invention can ensure the uniform distribution of ceramic particles in the pores. The direct immersion method is difficult to immerse because there is no external force, which may result in more ceramic particles in the pores near the base membrane surface and fewer ceramic particles inside the base membrane. The uneven distribution of ceramic particles leads to poor performance of the diaphragm. Moreover, the method of the present invention can minimize the amount of ceramic on the surface of the diaphragm, thereby avoiding the problem of poor interface caused by direct contact between ceramic particles and the positive and negative electrodes.

[0016] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0017] As a preferred technical solution for the preparation method of the composite ceramic diaphragm described in the present invention, the solid content of the suspension is 5%-20%, for example, 5%, 7%, 8%, 10%, 12.5%, 15%, 18% or 20%, etc. If the solid content of the suspension is too low, the suspension is too dilute, and the ceramic particles cannot fully enter the ceramic of the porous base membrane under the action of negative pressure, resulting in a low internal ceramic content of the prepared composite ceramic diaphragm; if the solid content of the suspension is too high, the suspension is too concentrated, and the ceramic particles are easily agglomerated, making it difficult to evenly disperse in the suspension, which in turn results in uneven distribution of surface ceramic particles after the suspension is applied to the surface of the porous base membrane. After subsequent negative pressure treatment, the ceramic particles entering the interior of the porous base membrane are unevenly distributed.

[0018] Preferably, the particle size of the ceramic in the suspension is 0.01 μm-3 μm, for example, 0.01 μm, 0.05 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm or 3 μm, etc.

[0019] Preferably, based on the dry basis mass of the suspension, the mass content of the ceramic is 5%-100%, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or, 95%, 97% or 100%, etc., preferably 5%-95%, more preferably 50%-95%.

[0020] Preferably, the ceramic includes a first inorganic ceramic, and the first inorganic ceramic is a nitride inorganic ceramic.

[0021] In addition to having good insulation properties, nitride inorganic ceramics also have excellent high-temperature resistance and thermal conductivity. When used in diaphragms, they can effectively improve the diaphragm's resistance to high-temperature shrinkage and enhance battery safety. Taking cubic boron nitride as an example, it has an extremely high melting point, excellent resistance to thermal shock and thermal stress, and good resistance to shrinkage at high temperatures. It also has good thermal conductivity and can conduct heat to other parts in a relatively short period of time. Therefore, it can play a good supporting role in the diaphragm at high temperatures, avoiding battery short circuits caused by diaphragm deformation, improving the diaphragm's resistance to high-temperature shrinkage, and ensuring the battery's high-temperature safety performance. In addition, nitride inorganic ceramics have a lower density, which can maximize the control of the overall quality of the battery.

[0022] Preferably, the nitride inorganic ceramic includes at least one of boron nitride, aluminum nitride, silicon nitride, titanium nitride and magnesium nitride. The above substances may exist in the form of a mixture or in the form of a composite.

[0023] Preferably, the boron nitride includes hexagonal boron nitride and / or N-type cubic boron nitride.

[0024] Preferably, the ceramic also includes a second inorganic ceramic, which includes at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, molybdenum-doped silicon dioxide, zirconium boride, zirconium nitride ceramics, silicon boride, vanadium boride, titanium boride, magnesium boride and inorganic ceramic solid electrolyte.

[0025] Preferably, the zirconium nitride compound includes at least one of ZrN, o-Zr3N4, and c-Zr3N4.

[0026] Preferably, the inorganic ceramic solid electrolyte includes at least one of lithium lanthanum zirconium oxide (LLZO), lithium lanthanum titanate oxide (LLTO), tantalum-doped lithium lanthanum zirconium oxide (LLZTO), aluminum-doped lithium lanthanum zirconium oxide (LLZAO), lithium germanium phosphorous sulfide (LGPS), lithium phosphorous sulfur chloride (LPSCl) and lithium aluminum germanium phosphate (LAGP).

[0027] Preferably, the mass of the second inorganic ceramic accounts for 0-95% of the mass of the first inorganic ceramic, for example, 0.05%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, 4.5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%, etc.

[0028] As a preferred technical solution of the method for preparing the composite ceramic diaphragm of the present invention, the suspension further includes a polymer binder and an organic solvent.

[0029] Preferably, the polymer binder includes at least one of polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinylidene fluoride-chlorotrifluoroethylene copolymer (PVDF-CTFE), polymethyl methacrylate (PMMA), polyacrylic acid (PAA), polyacrylonitrile (PAN), perfluorosulfonic acid resin (Nafion-H), perfluorosulfonic acid resin lithium (Nafion-Li), thermoplastic polyurethane (TPU), polyphenylene sulfide (PPS), polyethyleneimine, polyethyl cyanoacrylate (PCA), polyvinylene carbonate (PEC), polypropylene carbonate (PPC), polyvinyl carbonate (PVC), polymalonate substances, polysuccinate substances, polyimide (PI), polyetherimide and polyethersulfone (PESU);

[0030] Preferably, the polymalonate material includes at least one of polypentylene malonate (PPM), polyethylene malonate (PEM), polypropylene malonate (PTM) and polyhexylene malonate (PHM).

[0031] Preferably, the polysuccinate material includes at least one of polyethylene succinate (PES) and propylene succinate.

[0032] Preferably, the mass content of the polymer binder is 0%-95% and does not include endpoint values, such as 0.5%, 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 94%, etc., based on the dry basis mass of the suspension, preferably 3%-95%, more preferably 3%-50%.

[0033] The polymer binder content in the suspension is 3% to 50% by weight, for example, 3%, 4%, 4.5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%. If the polymer binder content is too low, the stability of the suspension will be reduced; if the polymer binder content is too high, the viscosity of the suspension will be too high, making it difficult for the ceramic particles to penetrate into the pores of the porous base membrane. The use of an appropriate amount of binder is conducive to the formation of a uniform and stable suspension system of ceramic particles.

[0034] Preferably, the organic solvent includes at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), nitrogen methyl pyrrolidone (NMP) and acetonitrile (ACN).

[0035] As a preferred technical solution of the method for preparing the composite ceramic diaphragm of the present invention, the suspension further includes a dispersant, and the dispersant includes at least one of a nonionic surfactant, an anionic surfactant, and a cationic surfactant.

[0036] In one embodiment, the anionic surfactant is polyvinylpyrrolidone (PVP).

[0037] In one embodiment, the nonionic surfactant is a fluorocarbon surfactant FSO.

[0038] Preferably, based on the dry basis mass of the suspension, the mass content of the dispersant is 0%-2% and does not contain 0%, such as 0.05%, 0.1%, 0.3%, 0.5%, 1%, 1.2%, 1.5%, 1.8% or 2%. The dry basis matter in the suspension refers to the total amount of other substances other than the solvent, such as ceramics, polymer binders and dispersants. By adding dispersants, the dispersibility of ceramic particles in the suspension can be improved. However, the content of dispersants should not be too much, because too much dispersant will cause the suspension to be unstable, thereby affecting the dropwise addition effect and the dispersion uniformity of ceramic particles in the composite ceramic diaphragm obtained, affecting the performance of the composite ceramic diaphragm.

[0039] Preferably, the suspension is applied to the surface of the porous base membrane by dropwise addition.

[0040] Preferably, the amount of suspension applied per unit area of ​​the porous base membrane surface is 0.08 mL / cm 2 -0.35mL / cm 2 , for example 0.08 mL / cm 2 , 0.10mL / cm 2 , 0.12mL / cm 2 , 0.15mL / cm 2 , 0.17mL / cm 2 , 0.18mL / cm 2 , 0.20mL / cm 2 , 0.22mL / cm 2 , 0.23mL / cm 2 , 0.25mL / cm 2 , 0.27mL / cm 2 , 0.28mL / cm 2 , 0.30mL / cm 2 , 0.33mL / cm 2 or 0.35 mL / cm 2The amount of addition mainly determines the ceramic content in the composite ceramic diaphragm. If the amount of addition is too little, the composite ceramic diaphragm will have too few ceramic particles, making it difficult to improve the diaphragm's strength and high-temperature resistance. If the amount of addition is too much, the composite ceramic diaphragm will have too many ceramic particles, which can easily block the pores of the porous base membrane.

[0041] Preferably, the negative pressure is 100 mbar-500 mbar, for example, 100 mbar, 150 mbar, 200 mbar, 220 mbar, 240 mbar, 260 mbar, 280 mbar, 300 mbar, 350 mbar, 400 mbar, 450 mbar or 500 mbar.

[0042] Preferably, the duration of the negative pressure is 30s-5min, for example, 30s, 40s, 50s, 1min, 1.5min, 2min, 2.5min, 3min, 3.5min, 4min, 4.5min or 5min, etc.

[0043] In the present invention, the purpose of applying negative pressure is primarily to cause the ceramic particles in the suspension to enter the pores of the porous base membrane and remain there. If the negative pressure is too low or the duration of the negative pressure is too short, the ceramic particles may not fully enter the pores of the porous base membrane. If the negative pressure is too high or the duration of the negative pressure is too long, the ceramic particles may pass through the pores of the porous base membrane and may not be retained there.

[0044] The method of the present invention can evenly distribute ceramic particles under relatively low pressure, has a simple preparation method and low energy consumption, and is suitable for large-scale production.

[0045] Preferably, the negative pressure is applied by using a suction filtration device to perform suction filtration on the porous basement membrane to which the suspension is applied.

[0046] Preferably, the porous base membrane includes any one of a porous polyethylene membrane, a porous polypropylene membrane, a porous polyethylene / polypropylene composite membrane, a porous cellulose membrane, a porous polyethylene terephthalate membrane, a porous polyimide membrane, a porous polyvinylidene fluoride membrane, a porous polyvinylidene fluoride-hexafluoropropylene copolymer membrane or a porous polytetrafluoroethylene membrane.

[0047] The present invention does not specifically limit the source of the porous base membrane. It can be a commercially available base membrane or prepared by existing preparation methods, which can be dry or wet processes. The pore size of the porous base membranes prepared by different methods varies to a certain extent.

[0048] In one embodiment, the porous base membrane is prepared by electrospinning or melt-blowing.

[0049] Preferably, the porosity of the porous base membrane is 40%-80%, for example, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%.

[0050] Preferably, in the porous base membrane, the pore size of the pores is 0.01μm-10μm, for example, 0.01μm, 0.05μm, 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.5μm, 2μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 5.5μm, 6μm, 6.5μm, 7μm, 7.5μm, 8μm, 8.5μm, 9μm, 9.5μm or 10μm, etc., preferably 0.01μm-1μm, preferably 0.03μm-5μm.

[0051] In second aspect, the present invention provides a composite ceramic diaphragm, which includes a porous base membrane and a composite ceramic material. The composite ceramic material includes ceramic, which is formed at least in the pores of the porous base membrane, and the particle size of the ceramic is smaller than the pore size of the pores; the ceramic includes a first inorganic ceramic, which is a nitride inorganic ceramic.

[0052] In the composite ceramic separator of the present invention, since the ceramic is at least located within the pores of the porous base membrane, it provides better stabilization and support than methods where the ceramic is placed on the surface of the base membrane. This results in improved high-temperature mechanical properties and enhanced high-temperature shrinkage resistance. Furthermore, the ceramic's location within the pores avoids the problem of poor interface quality caused by direct contact between ceramic particles and the positive and negative electrodes.

[0053] Furthermore, since the composite ceramic diaphragm of the present invention contains at least nitride inorganic ceramics, the comprehensive performance is further improved. Specifically: 1. Compared with other inorganic ceramics (such as aluminum oxide, silicon dioxide, etc.), nitride inorganic ceramics have a lower density, so the overall quality of the battery can be controlled to the maximum extent; 2. Nitride inorganic ceramics have good insulation properties and can avoid direct contact between the positive and negative poles; 3. Nitride inorganic ceramics have excellent high temperature resistance, which improves the high temperature shrinkage resistance of the diaphragm. At the same time, it has good thermal conductivity and can conduct heat to other parts in a shorter time. Therefore, it can play a good supporting role at high temperatures, avoid battery short circuit caused by diaphragm deformation, and ensure the safety performance of the battery at high temperatures.

[0054] In one embodiment, the composite ceramic diaphragm described in the second aspect is prepared using the preparation method described in the first aspect.

[0055] Preferably, the nitride inorganic ceramic includes at least one of boron nitride, aluminum nitride, silicon nitride, titanium nitride and magnesium nitride.

[0056] Preferably, the boron nitride includes hexagonal boron nitride and / or N-type cubic boron nitride.

[0057] Preferably, the ceramic also includes a second inorganic ceramic, which includes at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, molybdenum-doped silicon dioxide, zirconium boride, zirconium nitride ceramics, silicon boride, vanadium boride, titanium boride, magnesium boride and inorganic ceramic solid electrolyte.

[0058] Preferably, the zirconium nitride compound includes at least one of ZrN, o-Zr3N4, and c-Zr3N4.

[0059] Preferably, the inorganic ceramic solid electrolyte includes at least one of lithium lanthanum zirconium oxide, lithium lanthanum titanate oxide, tantalum-doped lithium lanthanum zirconium oxide, aluminum-doped lithium lanthanum zirconium oxide, lithium germanium phosphorus sulfur compound, lithium phosphorus sulfur chloride compound and lithium germanium aluminum phosphate.

[0060] Preferably, the mass of the second inorganic ceramic accounts for 0%-95% of the mass of the first inorganic ceramic, for example, 0.01%, 0.05%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 4%, 4.5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%, etc.

[0061] Preferably, in the composite ceramic diaphragm, the particle size of the ceramic is 0.01μm-3μm, for example, 0.01μm, 0.05μm, 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.5μm, 2μm, 2.5μm or 3μm, etc.

[0062] Preferably, based on the mass of the composite ceramic material being 100%, the mass content of the ceramic is 5%-100%, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, or 100%, preferably 5%-95%, more preferably 50%-95%. If the ceramic content is too low, the membrane cannot effectively support high temperatures; if the ceramic content is too high, the ceramic may clog the pores of the diaphragm, hindering the penetration of the electrolyte.

[0063] Preferably, the composite ceramic material further comprises a polymer binder, which can bind ceramic particles together, making the composite ceramic diaphragm have good flexibility and can be applied in the field of flexible devices.

[0064] Preferably, the polymer binder includes at least one of polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-chlorotrifluoroethylene, polyacrylic acid, polyacrylic acid, polyacrylonitrile, perfluorosulfonic acid resin, perfluorosulfonic acid resin lithium, thermoplastic polyurethane, polyphenylene sulfide, polyethyleneimine, polyethyl cyanoacrylate, polyvinylene carbonate, polypropylene carbonate, polyethylene carbonate, polymalonate substances, polysuccinate substances, polyimide, polyetherimide and polyethersulfone.

[0065] Preferably, the polymalonate material includes at least one of polypentylene malonate, polyethylene malonate, polypropylene malonate and polyhexylene malonate.

[0066] Preferably, the polysuccinate material includes at least one of polyethylene succinate and propylene succinate.

[0067] Preferably, based on the mass of the composite ceramic material as 100%, the mass content of the polymer binder is 0%-95% and does not contain endpoint values, such as 0.5%, 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 94%, etc., preferably 3%-95%, more preferably 3%-50%.

[0068] Preferably, the composite ceramic material further comprises a dispersant, and the dispersant comprises at least one of a nonionic surfactant, an anionic surfactant and a cationic surfactant.

[0069] Preferably, based on the mass of the composite ceramic material being 100%, the mass content of the dispersant is 0%-2% and does not include 0%, for example, 0.05%, 0.1%, 0.3%, 0.5%, 1%, 1.2%, 1.5%, 1.8% or 2%, etc.

[0070] Preferably, the thickness of the composite ceramic diaphragm is 5 μm-35 μm, for example, 5 μm, 7 μm, 8 μm, 10 μm, 12.5 μm, 15 μm, 17 μm, 20 μm, 23 μm, 26 μm, 30 μm, 32 μm, 34 μm or 35 μm.

[0071] Preferably, the porosity of the composite ceramic diaphragm is 30%-70%, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% or 70%.

[0072] In a third aspect, the present invention provides a battery comprising a positive electrode, a negative electrode and a separator, wherein the separator is located between the positive electrode and the negative electrode to isolate the positive electrode from the negative electrode, and the separator is a composite ceramic prepared by the method described in the first aspect or the composite ceramic separator described in the second aspect.

[0073] Preferably, a flexible interface is formed between the composite ceramic diaphragm and the positive electrode and / or between the composite ceramic diaphragm and the negative electrode.

[0074] The battery of the present invention has significantly improved safety performance due to the use of the composite ceramic diaphragm of the present invention. Furthermore, the mass energy density of the battery is increased due to the inclusion of nitride inorganic ceramics in the ceramic.

[0075] Preferably, the battery may be a solid-state battery or a semi-solid battery.

[0076] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0077] Compared with the prior art, the present invention has the following beneficial effects:

[0078] (1) The method of the present invention applies a suspension to the surface of a porous base membrane and applies negative pressure, so that the suspension can penetrate into the pores of the porous base membrane, thereby allowing the ceramic to enter the pores. In this way, the ceramic particles can be evenly distributed in the pores of the porous base membrane. The ceramic particles in the pores can still play a stable supporting role at high temperatures. The composite ceramic diaphragm is applied to batteries, and it can directly contact the positive electrode and the negative electrode respectively, thereby improving the safety performance of the battery.

[0079] (2) In the composite ceramic diaphragm of the present invention, since the ceramic is at least located in the pores of the porous base membrane, compared to the method of placing the ceramic on the surface of the base membrane, the ceramic can play a better stabilizing supporting role in the pores, and thus has better high-temperature mechanical properties, thereby improving the high-temperature shrinkage resistance of the diaphragm. At the same time, the ceramic is in the pores, avoiding the problem of poor interface caused by direct contact between ceramic particles and the positive and negative electrodes. Furthermore, since the composite ceramic diaphragm of the present invention contains at least nitride inorganic ceramics, the overall performance is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] FIG1 is a schematic structural diagram of a composite ceramic diaphragm in one embodiment of the present invention, wherein 1 is a porous base membrane, 11 is pores, and 2 is ceramics. DETAILED DESCRIPTION

[0081] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0082] In the embodiments of the present invention, the base film used can be prepared by methods disclosed in the prior art, or can be a commercially available product.

[0083] Example 1

[0084] A composite ceramic diaphragm, the structural schematic of which is shown in FIG1 , includes a porous base membrane 1 and a composite ceramic material. The composite ceramic material includes a ceramic 2, which is formed at least in the pores 11 of the porous base membrane 1, and the particle size of the ceramic 2 is smaller than the pore size of the pores 11. The ceramic 2 includes a first inorganic ceramic, which is a nitride inorganic ceramic, and the particle size of the ceramic is 0.5 μm.

[0085] The nitride inorganic ceramic is hexagonal BN;

[0086] The composite ceramic material further comprises a polymer binder and a dispersant, wherein the polymer binder is polyvinylidene fluoride (PVDF) and the dispersant is polyvinyl pyrrolidone (PVP);

[0087] Based on the mass of the composite ceramic material being 100%, the mass content of the ceramic is 90%, the mass content of the polymer binder is 9%, and the mass content of the dispersant is 1%.

[0088] The preparation method of the composite ceramic diaphragm provided in this embodiment includes the following steps:

[0089] Hexagonal BN particles with a particle size of 0.5 μm, PVP and PVDF were dispersed in N,N-dimethylformamide (DMF) and stirred to obtain a suspension with a solid content of 10%;

[0090] Take a porous base membrane (polypropylene base membrane) with a pore size of 5 μm and a porosity of 50%, and drop the above suspension onto the surface of the porous base membrane. The drop amount per unit area is 0.2 mL / cm 2 , and then the suspension is filtered to allow it to penetrate into the porous base membrane. The negative pressure generated during the filtration process is 300 mbar. The vacuum is removed after the negative pressure lasts for 1 minute. The filtered membrane is naturally dried and then placed in a vacuum oven at 60°C for 24 hours to obtain the composite ceramic membrane.

[0091] Example 2

[0092] A composite ceramic diaphragm, comprising a porous base membrane and a composite ceramic material, wherein the composite ceramic material comprises ceramic, the ceramic being formed at least in pores of the porous base membrane, and having a particle size smaller than that of the pores; the ceramic comprising a first inorganic ceramic, the first inorganic ceramic being a nitride inorganic ceramic, and having a particle size of 1 μm;

[0093] The nitride inorganic ceramic is AlN;

[0094] The composite ceramic material further comprises a polymer binder and a dispersant, wherein the polymer binder is polyethylene oxide (PEO) and the dispersant is PVP;

[0095] Based on the mass of the composite ceramic material being 100%, the mass content of the ceramic is 85%, the mass content of the polymer binder is 14.5%, and the mass content of the dispersant is 0.5%.

[0096] The preparation method of the composite ceramic diaphragm provided in this embodiment includes the following steps:

[0097] AlN particles with a particle size of 1 μm, PVP and PEO were dispersed in N,N-dimethylacetamide (DMAC) and stirred to obtain a suspension with a solid content of 15%;

[0098] Take a porous base membrane (polypropylene base membrane) with a pore size of 10 μm and a porosity of 80%, and drop the above suspension onto the surface of the porous base membrane. The drop amount per unit area is 0.3 mL / cm 2 , and then the suspension is filtered to allow it to penetrate into the porous base membrane. The negative pressure generated during the filtration process is 400 mbar. The vacuum is removed after the negative pressure lasts for 3 minutes. The filtered membrane is naturally dried and then placed in a vacuum oven at 80°C for 10 hours to obtain the composite ceramic membrane.

[0099] Example 3

[0100] A composite ceramic diaphragm, comprising a porous base membrane and a composite ceramic material, wherein the composite ceramic material comprises ceramic, the ceramic being formed at least in pores of the porous base membrane, and having a particle size smaller than that of the pores; the ceramic comprising a first inorganic ceramic, the first inorganic ceramic being a nitride inorganic ceramic, and having a particle size of 0.05 μm;

[0101] The nitride inorganic ceramic is Si3N4;

[0102] The composite ceramic material further comprises a polymer binder and a dispersant, wherein the polymer binder is polymethyl methacrylate (PMMA) and the dispersant is PVP;

[0103] Based on the mass of the composite ceramic material being 100%, the mass content of the ceramic is 65%, the mass content of the polymer binder is 33.5%, and the mass content of the dispersant is 1.5%.

[0104] The preparation method of the composite ceramic diaphragm provided in this embodiment includes the following steps:

[0105] Si3N4 particles with a particle size of 0.05 μm, PVP and PMMA were dispersed in nitrogen methyl pyrrolidone (NMP) and stirred to obtain a suspension with a solid content of 8%;

[0106] Take a porous base membrane (polypropylene base membrane) with a pore size of 0.5 μm and a porosity of 40%, and drop the above suspension onto the surface of the porous base membrane. The drop amount per unit area is 0.25 mL / cm 2 , and then the suspension is filtered to allow it to penetrate into the porous base membrane. The negative pressure generated during the filtration process is 200 mbar. The vacuum is removed after the negative pressure lasts for 5 minutes. The filtered membrane is naturally dried and then placed in a vacuum oven at 90°C for 8 hours to obtain the composite ceramic membrane.

[0107] Example 4

[0108] A composite ceramic diaphragm, comprising a porous base membrane and a composite ceramic material, wherein the composite ceramic material comprises ceramic, the ceramic being formed at least in pores of the porous base membrane, and having a particle size smaller than that of the pores; the ceramic comprising a first inorganic ceramic, the first inorganic ceramic being a nitride inorganic ceramic, and having a particle size of 0.2 μm;

[0109] The nitride inorganic ceramic is AlN;

[0110] The composite ceramic material further includes a polymer binder and a dispersant, wherein the polymer binder is polyacrylonitrile (PAN) and the dispersant is PVP;

[0111] Based on the mass of the composite ceramic material being 100%, the mass content of the ceramic is 85%, the mass content of the polymer binder is 14.5%, and the mass content of the dispersant is 0.5%.

[0112] The preparation method of the composite ceramic diaphragm provided in this embodiment includes the following steps:

[0113] AlN particles with a particle size of 0.2 μm, PVP and PAN were dispersed in DMF and stirred to obtain a suspension with a solid content of 5%;

[0114] Take a porous base film (polyethylene base film) with a pore size of 2 μm and a porosity of 55%, and drop the above suspension onto the surface of the porous base film. The drop amount per unit area is 0.09 mL / cm 2 , and then the suspension is filtered to allow it to penetrate into the porous base membrane. The negative pressure generated during the filtration process is 150 mbar. The negative pressure is maintained for 4.5 minutes and then the vacuum is removed. The filtered membrane is naturally dried and placed in a vacuum oven at 70°C for 18 hours to obtain the composite ceramic membrane.

[0115] Example 5

[0116] A composite ceramic diaphragm includes a porous base membrane and a composite ceramic material, wherein the composite ceramic material includes ceramic, the ceramic is formed at least in the pores of the porous base membrane, and the particle size of the ceramic is smaller than the pore size of the pores; the ceramic includes a first inorganic ceramic and a second inorganic ceramic, the first inorganic ceramic is a nitride inorganic ceramic, the second inorganic ceramic is lithium lanthanum zirconium oxide (LLZO), the mass of the second inorganic ceramic accounts for 50% of the mass of the first inorganic ceramic, and the particle size of the ceramic is 0.5 μm;

[0117] The nitride inorganic ceramic is cubic boron nitride;

[0118] The composite ceramic material further includes a polymer binder and a dispersant, wherein the polymer binder is PVDF and the dispersant is PVP;

[0119] Based on the mass of the composite ceramic material being 100%, the mass content of the ceramic is 88%, the mass content of the polymer binder is 11%, and the mass content of the dispersant is 1%.

[0120] The preparation method of the composite ceramic diaphragm provided in this embodiment includes the following steps:

[0121] Cubic boron nitride particles with a particle size of 0.5 μm, LLZO with a particle size of 0.5 μm, PVP and PVDF were dispersed in DMF and stirred to obtain a suspension with a solid content of 15%;

[0122] Take a porous base membrane (polypropylene base membrane) with a pore size of 10 μm and a porosity of 80%, and drop the above suspension onto the surface of the porous base membrane. The drop amount per unit area is 0.3 mL / cm 2 , and then the suspension is filtered to allow it to penetrate into the porous base membrane. The negative pressure generated during the filtration process is 400 mbar. The vacuum is removed after the negative pressure lasts for 3 minutes. The filtered membrane is naturally dried and then placed in a vacuum oven at 80°C for 10 hours to obtain the composite ceramic membrane.

[0123] Example 6

[0124] A composite ceramic diaphragm and a preparation method thereof, which differ from Example 1 only in that the composite ceramic diaphragm does not contain a dispersant PVP.

[0125] Example 7

[0126] A composite ceramic diaphragm and a preparation method thereof, which differ from Example 1 only in that the content of the dispersant PVP is 3%, and correspondingly, the content of the polymer binder is 7%.

[0127] Example 8

[0128] A composite ceramic diaphragm and a preparation method thereof are different from Example 1 only in that, in the preparation method of the composite ceramic diaphragm, the amount of the solvent DMF is changed so that the solid content of the suspension is 3%.

[0129] Example 9

[0130] A composite ceramic diaphragm and a preparation method thereof are different from Example 1 only in that, in the preparation method of the composite ceramic diaphragm, the amount of the solvent DMF is changed so that the solid content of the suspension is 22%.

[0131] Example 10

[0132] A composite ceramic diaphragm and a preparation method thereof, which differ from Example 1 only in that, in the preparation method of the composite ceramic diaphragm, the negative pressure is 280 mbar.

[0133] Example 11

[0134] A composite ceramic diaphragm and a preparation method thereof, which differ from Example 1 only in that, in the preparation method of the composite ceramic diaphragm, the negative pressure is 520 mbar.

[0135] Example 12

[0136] A composite ceramic diaphragm and a preparation method thereof, which differ from Example 1 only in that, in the preparation method of the composite ceramic diaphragm, the negative pressure duration is 20 seconds.

[0137] Example 13

[0138] A composite ceramic diaphragm and a preparation method thereof, which differ from Example 1 only in that, in the preparation method of the composite ceramic diaphragm, the negative pressure duration is 5.2 minutes.

[0139] Example 14

[0140] A composite ceramic diaphragm and a preparation method thereof, which differs from Example 1 only in that, in the preparation method of the composite ceramic diaphragm, the dripping amount per unit area is 0.05 mL / cm 2 .

[0141] Example 15

[0142] A composite ceramic diaphragm and a preparation method thereof, which differs from Example 1 only in that, in the preparation method of the composite ceramic diaphragm, the dripping amount per unit area is 0.38 mL / cm 2 .

[0143] Comparative Example 1

[0144] A composite ceramic diaphragm and a preparation method thereof, which differ from Example 1 only in that no filtration treatment is performed in the preparation method of the composite ceramic diaphragm.

[0145] Comparative Example 2

[0146] A composite ceramic diaphragm and a preparation method thereof, which differ from Example 1 only in that, in the preparation method of the composite ceramic diaphragm, the nitride inorganic ceramic in Example 1 is replaced by Al2O3.

[0147] Comparative Example 3

[0148] A composite ceramic diaphragm and a preparation method thereof, which differ from Example 1 only in that, in the preparation method of the composite ceramic diaphragm, the nitride inorganic ceramic in Example 1 is replaced by LLZO.

[0149] Application Example 1

[0150] A lithium-ion battery comprises a positive electrode, a negative electrode, a separator (the composite ceramic separator of Example 1) and an electrolyte, and a method for preparing the lithium-ion battery comprises the following steps:

[0151] According to the mass ratio of lithium iron phosphate (LFP): SuperP:PVDF = 8:1:1, LFP, Super P and PVDF were dispersed in DMF and the solid content was controlled to 60% to obtain a positive electrode slurry. The positive electrode slurry was coated on aluminum foil with a scraper with a thickness of 100 μm and dried for use.

[0152] The electrolyte composition is: 1 mol / L LiPF6 as electrolyte and a mixture of EC:DMC (volume ratio) = 1:1 as solvent.

[0153] A lithium sheet with a thickness of 100 μm was used as the counter electrode and a button cell of model 2032 was assembled in an inert gas glove box with a water and oxygen content of less than 0.1 ppm.

[0154] Application Example 2-15

[0155] A lithium-ion battery differs from Application Example 1 only in that the composite ceramic diaphragms of Examples 2-15 are used to replace the composite ceramic diaphragm of Example 1.

[0156] Application Comparative Examples 1-3

[0157] A lithium ion battery differs from Application Example 1 only in that the composite ceramic diaphragms of Examples 1-3 are used to replace the composite ceramic diaphragm of Example 1.

[0158] Performance testing:

[0159] (1) Diaphragm thickness: Use a micrometer to measure the thickness of the diaphragm.

[0160] (2) Porosity of the diaphragm: The porosity of the diaphragm was tested using a mercury intrusion instrument.

[0161] (3) Thermal shrinkage of the diaphragm: The diaphragm was placed in an oven at 150°C and kept warm for 1 hour before being taken out. The longitudinal and transverse lengths before and after the heat treatment were measured. The percentage of the change in longitudinal and transverse length to the initial length was calculated. The initial length was recorded as d0, and the length after shrinkage was recorded as d1. Thermal shrinkage = (d0-d1) / d0×100%.

[0162] (4) Discharge capacity: The charge and discharge test was performed at room temperature with a current density of 0.1C.

[0163] (5) Interface impedance: Call the EIS program through the electrochemical workstation, set the frequency range to 1 Hz to 1 MHz, and test the interface impedance after one cycle of the battery.

[0164] The thickness, porosity and thermal shrinkage of the composite ceramic diaphragms of Examples 1-15 and Comparative Examples 1-3 were tested according to the above test methods. The test results are shown in Table 1.

[0165] The interface impedance and discharge capacity tests were performed on the lithium-ion batteries of Examples 1-15 and Comparative Examples 1-3. The results are shown in Table 2.

[0166] Table 1

[0167] Table 2

[0168] As shown in Tables 1 and 2, the composite ceramic separator of the present invention exhibits excellent shrinkage resistance, effectively improving battery safety. Furthermore, because the preparation method utilizes negative pressure to introduce the ceramic into the pores of the base membrane, the problem of poor interfacial properties caused by contact between the ceramic on the base membrane surface and the positive and negative electrodes is avoided.

[0169] By comparing Example 1 with Examples 6-7, it can be seen that the dispersibility of ceramic particles in the suspension can be improved by adding dispersants. However, too much dispersant content will cause the suspension to be unstable, thereby affecting the dropwise addition effect and the dispersion uniformity of ceramic particles in the final composite ceramic diaphragm, affecting the performance of the composite ceramic diaphragm. Moreover, too much dispersant in Example 7 will reduce the content of the binder in the composite ceramic diaphragm, resulting in lower adhesion of the ceramic in the composite diaphragm, affecting the anti-shrinkage performance of the composite ceramic diaphragm.

[0170] By comparing Example 1 with Examples 8-9, it can be seen that the solid content of the suspension is in the range of 5%-20%, which is conducive to the ceramic particles fully entering the pores of the porous base membrane and making the ceramics evenly distributed in the pores, thereby facilitating the improvement of the performance of the composite diaphragm.

[0171] By comparing Example 1 with Examples 10-11 and Examples 12-13, it can be seen that the magnitude of the negative pressure and the duration of the negative pressure have an important influence on the performance of the composite ceramic diaphragm. If the negative pressure value is too small or the duration of the negative pressure is too short, the ceramic particles cannot fully enter the pores of the porous base membrane; if the negative pressure value is too large or the duration of the negative pressure is too long, it may cause the ceramic particles to pass through the pores of the porous base membrane and cannot be retained in the pores. The above factors will lead to a low content of ceramic in the composite ceramic diaphragm, thereby deteriorating the anti-shrinkage performance of the diaphragm.

[0172] By comparing Example 1 with Examples 14-15, it can be seen that the amount of the suspension added to the surface of the porous base membrane is 0.08 mL / cm 2 -0.35mL / cm 2 When the content of ceramic particles in the composite ceramic diaphragm is adjusted appropriately, the problem of pore blocking will not occur. The combined effect of the above two factors makes the performance of the composite ceramic diaphragm better.

[0173] By comparing Example 1 with Comparative Example 1, it can be seen that Comparative Example 1 does not undergo negative pressure treatment, resulting in the ceramic particles still being located on the surface. On the one hand, this results in poor interface contact, and on the other hand, the ceramic particles cannot effectively play a role in stable support, thereby reducing the thermal shrinkage resistance. Therefore, the interface performance and thermal shrinkage resistance of Comparative Example 1 are both worse than those of Example 1.

[0174] By comparing Example 1 with Comparative Examples 2-3, it can be seen that when Al2O3 and LLZO are used in the composite diaphragm, their thermal shrinkage resistance is worse than that of nitride inorganic ceramics.

[0175] The applicant states that the present invention is intended to illustrate the detailed methods of the present invention through the above-described embodiments, but the present invention is not limited to the above-described detailed methods, that is, it does not mean that the present invention must rely on the above-described detailed methods in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for various raw materials in the products of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., are all within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a composite ceramic diaphragm, characterized in that: The preparation method comprises the following steps: providing a suspension comprising a ceramic; Applying the suspension to the surface of a porous base membrane, applying negative pressure to allow the suspension to penetrate into the pores of the porous base membrane, and obtaining a composite ceramic diaphragm after drying; Wherein, the particle size of the ceramic is smaller than the pore size of the pore.

2. The method for preparing the composite ceramic diaphragm according to claim 1, characterized in that: The solid content of the suspension is 5%-20%; Preferably, based on the dry mass of the suspension, the mass content of the ceramic is 5%-100%, preferably 5%-95%, more preferably 50%-95%; Preferably, the particle size of the ceramic is 0.01 μm-3 μm; Preferably, the ceramic includes a first inorganic ceramic, and the first inorganic ceramic is a nitride inorganic ceramic; Preferably, the nitride inorganic ceramic includes at least one of boron nitride, aluminum nitride, silicon nitride, titanium nitride and magnesium nitride; Preferably, the boron nitride includes hexagonal boron nitride and / or N-type cubic boron nitride; Preferably, the ceramic further includes a second inorganic ceramic, and the second inorganic ceramic includes at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, molybdenum-doped silicon dioxide, zirconium boride, zirconium nitride ceramics, silicon boride, vanadium boride, titanium boride, magnesium boride and an inorganic ceramic solid electrolyte; Preferably, the zirconium nitride compound includes at least one of ZrN, o-Zr3N4, and c-Zr3N4; Preferably, the inorganic ceramic solid electrolyte includes lithium lanthanum zirconium oxide, lanthanum titanate lithium oxide, tantalum-doped lithium lanthanum zirconium oxide, aluminum-doped lithium lanthanum zirconium oxide, lithium germanium phosphorus sulfur, lithium phosphorus At least one of a sulfur chloride compound and lithium germanium aluminum phosphate; Preferably, the mass of the second inorganic ceramic accounts for 0-95% of the mass of the first inorganic ceramic.

3. The method for preparing a composite ceramic diaphragm according to claim 1 or 2, wherein the suspension further comprises a polymer binder and an organic solvent; Preferably, the polymer binder includes at least one of polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-chlorotrifluoroethylene, polyacrylic acid, polyacrylic acid, polyacrylonitrile, perfluorosulfonic acid resin, perfluorosulfonic acid resin lithium, thermoplastic polyurethane, polyphenylene sulfide, polyethyleneimine, polyethyl cyanoacrylate, polyvinylene carbonate, polypropylene carbonate, polyvinyl carbonate, polymalonate, polysuccinate, polyimide, polyetherimide and polyethersulfone; Preferably, the polymalonate material includes at least one of polypentylene malonate, polyethylene malonate, polypropylene malonate and polyhexylene malonate; Preferably, the polysuccinate material includes at least one of polyethylene succinate and propylene succinate; Preferably, based on the dry basis weight of the suspension, the mass content of the polymer binder is 0%-95% and does not include endpoint values, preferably 3%-95%, more preferably 3%-50%; Preferably, the organic solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, nitrogen methyl pyrrolidone and acetonitrile.

4. The method for preparing a composite ceramic diaphragm according to any one of claims 1 to 3, wherein the suspension further comprises a dispersant, and the dispersant comprises at least one of a nonionic surfactant, an anionic surfactant and a cationic surfactant; Preferably, based on the dry basis weight of the suspension, the mass content of the dispersant is 0%-2% and does not include 0%.

5. The method for preparing the composite ceramic diaphragm according to any one of claims 1 to 4, characterized in that: The suspension is applied to the surface of the porous base membrane by dropwise addition; Preferably, the amount of suspension applied per unit area of ​​the porous substrate surface is 0.08 mL / cm 2 -0.35mL / cm 2 .

6. The method for preparing a composite ceramic diaphragm according to any one of claims 1 to 5, characterized in that: The negative pressure is 100mbar-500mbar; Preferably, the duration of the negative pressure is 30s-5min; Preferably, the negative pressure is applied by using a suction filtration device to perform suction filtration on the porous base membrane to which the suspension is applied.

7. The method for preparing a composite ceramic diaphragm according to any one of claims 1 to 6, characterized in that: The porous base membrane includes any one of a porous polyethylene membrane, a porous polypropylene membrane, a porous polyethylene / polypropylene composite membrane, a porous cellulose membrane, a porous polyethylene terephthalate membrane, a porous polyimide membrane, a porous polyvinylidene fluoride membrane, a porous polyvinylidene fluoride-hexafluoropropylene copolymer membrane or a porous polytetrafluoroethylene membrane; Preferably, the porosity of the porous base membrane is 40%-80%; Preferably, in the porous base membrane, the pore size is 0.01 μm-10 μm, preferably 0.03 μm-5 μm.

8. A composite ceramic diaphragm, characterized in that: The composite ceramic diaphragm includes a porous base membrane and a composite ceramic material. The composite ceramic material includes ceramics. The ceramics are at least formed in the pores of the porous base membrane. The particle size of the ceramics is smaller than the pore size of the pores. The ceramics include a first inorganic ceramic, which is a nitride inorganic ceramic.

9. The composite ceramic diaphragm according to claim 8, characterized in that: The nitride inorganic ceramic includes at least one of boron nitride, aluminum nitride, silicon nitride, titanium nitride and magnesium nitride; Preferably, the boron nitride includes hexagonal boron nitride and / or N-type cubic boron nitride; Preferably, the ceramic further includes a second inorganic ceramic, and the second inorganic ceramic includes at least one of aluminum oxide, titanium dioxide, silicon dioxide, zirconium dioxide, molybdenum-doped silicon dioxide, zirconium boride, zirconium nitride ceramics, silicon boride, vanadium boride, titanium boride, magnesium boride and an inorganic ceramic solid electrolyte; Preferably, the zirconium nitride compound includes at least one of ZrN, o-Zr3N4, and c-Zr3N4; Preferably, the inorganic ceramic solid electrolyte includes at least one of lithium lanthanum zirconium oxide, lanthanum titanate lithium oxide, tantalum-doped lithium lanthanum zirconium oxide, aluminum-doped lithium lanthanum zirconium oxide, lithium germanium phosphorus-sulfur compound, lithium phosphorus-sulfur-chloride compound and lithium germanium aluminum phosphate; Preferably, the mass of the second inorganic ceramic accounts for 0-95% of the mass of the first inorganic ceramic; Preferably, in the composite ceramic diaphragm, the particle size of the ceramic is 0.01 μm-3 μm; Preferably, based on the mass of the composite ceramic material being 100%, the mass content of the ceramic is 5%-100%, preferably 5%-95%, more preferably 50%-95%; Preferably, the composite ceramic material further comprises a polymer binder; Preferably, the polymer binder includes at least one of polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-chlorotrifluoroethylene, polyacrylic acid, polyacrylic acid, polyacrylonitrile, perfluorosulfonic acid resin, perfluorosulfonic acid resin lithium, thermoplastic polyurethane, polyphenylene sulfide, polyethyleneimine, polyethyl cyanoacrylate, polyvinylene carbonate, polypropylene carbonate, polyvinyl carbonate, polymalonate, polysuccinate, polyimide, polyetherimide and polyethersulfone; Preferably, the polymalonate material includes at least one of polypentylene malonate, polyethylene malonate, polypropylene malonate and polyhexylene malonate; Preferably, the polysuccinate material includes polyethylene succinate and propylene succinate. At least one of; Preferably, based on the mass of the composite ceramic material being 100%, the mass content of the polymer binder is 0%-95% and does not include endpoint values, preferably 3%-95%, more preferably 3%-50%; Preferably, the composite ceramic material further comprises a dispersant, and the dispersant comprises at least one of a nonionic surfactant, an anionic surfactant and a cationic surfactant; Preferably, based on 100% of the mass of the composite ceramic material, the mass content of the dispersant is 0%-2% and does not contain 0%; Preferably, the thickness of the composite ceramic diaphragm is 5 μm-35 μm; Preferably, the porosity of the composite ceramic diaphragm is 30%-70%.

10. A battery comprising a positive electrode, a negative electrode and a separator, wherein the separator is located between the positive electrode and the negative electrode to isolate the positive electrode from the negative electrode, characterized in that: The diaphragm is a composite ceramic diaphragm prepared by the method according to any one of claims 1 to 7 or a composite ceramic diaphragm according to claim 8 or 9; Preferably, the battery is a quasi-solid-state battery or a semi-solid-state battery; Preferably, a flexible interface is formed between the composite ceramic diaphragm and the positive electrode and / or between the composite ceramic diaphragm and the negative electrode.

Images