A lithium battery ceramic separator binder and its preparation method, and a lithium battery

Abstract

This application belongs to the field of lithium battery technology, and particularly relates to a lithium battery ceramic separator adhesive, its preparation method, and a lithium battery. The lithium battery ceramic coated separator adhesive includes a core layer and a shell layer. The shell layer is a copolymer of alkyl acrylate and acrylate polyacrylate with a mass ratio of 1:1 to 3. The glass transition temperature is about -10℃ to -30℃. It is in a glassy state at room temperature and has good viscoelasticity. It can effectively bond the positive and negative electrode sheets and the battery ceramic separator at room temperature after conventional pressing. The positive and negative electrode sheets and the battery ceramic separator are difficult to peel off or move. This solves the technical problem in the prior art that the bonding effect of lithium battery ceramic separator adhesive at room temperature is poor and the electrode sheets and separator are prone to displacement.

Description

Technical Field

[0001] This application belongs to the field of lithium battery technology, and particularly relates to a lithium battery ceramic separator binder, its preparation method, and a lithium battery. Background Technology

[0002] The two sides of a lithium-ion battery separator are the positive and negative electrodes. The purpose of the separator is to separate the positive and negative lithium ions while allowing electrolyte ions to move freely. Currently, widely used lithium-ion battery separators are polyolefin membranes such as polyethylene and polypropylene membranes. However, with the development of lithium-ion battery technology, higher requirements have been placed on lithium-ion battery separators. Traditional polyolefin membranes such as polyethylene and polypropylene membranes have low melting points and are prone to shrinkage or melting at high temperatures, which can cause short circuits and other dangerous situations due to contact between the positive and negative electrodes. To improve the thermal stability of polyolefin membranes, [further measures are needed]. A ceramic-coated separator is prepared by coating the membrane surface with a layer of inorganic particles such as silica, resulting in a lithium battery ceramic separator. This improves the thermal stability of the polyolefin separator and reduces the possibility of contact between the positive and negative electrodes of the lithium battery due to shrinkage or melting of the polyolefin separator. At the same time, since lithium batteries often face complex operating environments, the electrode sheets and separator may shift during use, leading to direct contact between the positive and negative electrodes and causing a short circuit. Therefore, the lithium battery ceramic separator is coated with an adhesive and then pressed together with the positive and negative electrode sheets to reduce the probability of displacement of the electrode sheets and separator during use.

[0003] Currently, polyvinylidene fluoride (PVDF) is the most commonly used binder. However, PVDF does not bond well at room temperature and needs to be dissolved in organic solvents such as N-methylpyrrolidone. The positive and negative electrodes of lithium batteries are then bonded to the separator through a hot-pressing process. This process is complex, and the use of organic solvents does not conform to the concept of green environmental protection. Summary of the Invention

[0004] In view of this, this application provides a lithium battery ceramic separator adhesive, a preparation method thereof, and a lithium battery, to solve the technical problem that the bonding effect of the lithium battery ceramic separator adhesive is poor at room temperature and the electrode sheet and separator are prone to displacement in the prior art.

[0005] The first aspect of this application provides a lithium battery ceramic separator binder, including a core layer and a shell layer;

[0006] The core layer is a styrene-based polymer;

[0007] The shell layer is polyacrylate;

[0008] The monomers of the polyacrylate are alkyl acrylates and acrylates;

[0009] The mass ratio of the alkyl acrylate to the acrylate is 1:1 to 3.

[0010] Preferably, the particle size of the lithium battery ceramic separator binder is 1 to 3 micrometers.

[0011] Preferably, the particle size of the lithium battery ceramic separator binder is 1.5 to 2 micrometers.

[0012] Preferably, the mass ratio of the core layer to the shell layer is 1:1 to 2.

[0013] Preferably, the styrene monomer of the styrene polymer is selected from any one or at least two of styrene, α-methylstyrene, divinylbenzene, and phenyl methacrylate.

[0014] Preferably, the styrene monomer of the styrene polymer is styrene.

[0015] Preferably, the alkyl acrylate monomer in the polyacrylate monomer is selected from any one or at least two of methyl methacrylate, ethyl methacrylate, and butyl methacrylate;

[0016] The acrylate monomer in the polyacrylate is selected from any one or at least two of methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, and isooctyl acrylate.

[0017] Preferably, the alkyl acrylate monomer in the polyacrylate monomer is methyl methacrylate;

[0018] The acrylate monomer in the polyacrylate monomer is methyl acrylate.

[0019] Preferably, the mass ratio of methyl methacrylate to methyl acrylate is 8:17;

[0020] The mass ratio of the core to the shell is 1:1.

[0021] The second aspect of this application provides a method for preparing a lithium battery ceramic separator binder, comprising the steps of:

[0022] Step S1: After mixing styrene monomers, initiators and solvents, a core-layer polymerization reaction is carried out to obtain a styrene polymer dispersion.

[0023] Step S2: The styrene polymer dispersion, acrylate monomer, alkyl acrylate monomer, dispersion stabilizer polyvinylpyrrolidone, initiator, emulsifier and solvent water are subjected to shell polymerization reaction to obtain lithium battery ceramic separator binder dispersion.

[0024] In step S2, the mass ratio of the alkyl acrylate to the acrylate is 1:1 to 3.

[0025] Preferably, in step S1, the temperature of the core-layer polymerization reaction is 65-75°C, and the time is 12-24 hours.

[0026] Preferably, in steps S1 and S2, the initiator oil is a soluble initiator.

[0027] Preferably, the soluble initiator is selected from any one or at least two of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, 2-ethylhexyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, diphenoxyethyl peroxydicarbonate, bis(3,5,5-trimethylacetyl peroxide), and cumyl peroxydicarboxylate.

[0028] Preferably, the soluble initiator is selected from azobisisobutyronitrile and benzoyl peroxide.

[0029] Preferably, the solvent is a mixture of an organic solvent and water.

[0030] Preferably, the organic solvent is a hydrophilic organic solvent;

[0031] The hydrophilic organic solvent is selected from any one or at least two of ethanol, methanol, propanol, isopropanol, acetone, butanone, and ethylene glycol methyl ether.

[0032] Preferably, in step S2, the temperature of the shell polymerization reaction is 60-80°C and the time is 9-15 hours.

[0033] Preferably, in step S2, the emulsifier is an anionic emulsifier;

[0034] The anionic emulsifier is selected from any one or at least two of sodium p-toluenesulfonate, sodium acrylate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium diisooctyl succinate.

[0035] A third aspect of this application provides a lithium battery, including a lithium battery ceramic separator, a positive electrode, a negative electrode, the aforementioned binder, and an electrolyte;

[0036] The positive electrode and the negative electrode are adhered to both sides of the lithium battery ceramic separator by the adhesive.

[0037] The lithium battery ceramic separator, positive electrode, negative electrode, and the aforementioned binder are immersed in the electrolyte.

[0038] In summary, this application provides a lithium battery ceramic separator adhesive, its preparation method, and a lithium battery. The lithium battery ceramic coated separator adhesive comprises a core layer and a shell layer. The core layer is a styrene-based polymer, and the shell layer is a copolymer of acrylate and alkyl acrylate polyacrylate. The phenyl groups in the core layer styrene-based polymer result in a much higher hardness than the copolymer of acrylate and alkyl acrylate in the shell layer, yielding a "hard core, soft shell" adhesive. The shell polyacrylate formed by copolymerizing alkyl acrylate and the acrylate in a mass ratio of 1:1 to 3 has a low glass transition temperature, approximately -10°C to -30°C. It is in a glassy state at room temperature, exhibiting good viscoelasticity. This allows for excellent bonding of the positive and negative electrode sheets and the battery ceramic separator at room temperature after conventional pressing. The peel strength between the positive and negative electrode sheets and the battery ceramic separator is high, making them difficult to peel off or move. This solves the technical problem in the prior art where the bonding effect of lithium battery ceramic separator adhesives at room temperature is poor, and the electrode sheets and separator are prone to displacement. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0040] Figure 1 The image shows the particle size test results of the lithium battery ceramic separator binder provided in Example 1 of this application.

[0041] Figure 2 The graph shows the particle size test results of the lithium battery ceramic separator binder provided in Comparative Example 2 of this application. Detailed Implementation

[0042] This application provides a lithium battery ceramic separator adhesive, its preparation method, and a lithium battery, which solves the technical problem that the existing lithium battery ceramic separator adhesive has poor bonding effect at room temperature and that the electrode sheets and separator are prone to displacement.

[0043] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] Example 1

[0045] This embodiment provides a lithium battery ceramic separator adhesive with a core-shell structure. The core layer is a styrene polymer, and the shell layer is a copolymer of acrylate and alkyl acrylate polyacrylate. The phenyl groups in the core styrene polymer make its hardness much higher than that of the shell layer copolymer of acrylate and alkyl acrylate. Thus, this application provides a "hard core, soft shell" adhesive. The shell polyacrylate formed by copolymerizing alkyl acrylate and acrylate in a mass ratio of 1:1 to 3 has a low glass transition temperature, around -10°C to -30°C. It is in a glassy state at room temperature and has good viscoelasticity. It can effectively bond the positive and negative electrode sheets and the battery ceramic separator at room temperature after conventional pressing. The peel strength between the positive and negative electrode sheets and the battery ceramic separator can reach 13.3 N / m. The high peel strength makes it difficult for the positive and negative electrode sheets and the battery ceramic separator to peel off or move. This solves the technical problem in the prior art that the bonding effect of lithium battery ceramic separator adhesives at room temperature is poor and the electrode sheets and separator are prone to displacement.

[0046] Preferably, the lithium battery ceramic separator binder provided in this application has a particle size of 1-3 micrometers, more preferably 1.5-2 micrometers. The lithium battery ceramic separator binder provided in this application has a relatively large particle size, with a median particle size D50 of about 1.8 micrometers, of which the core layer particle size can reach about 1.5 micrometers. The shell layer of the binder is in a glassy state at room temperature and has good viscoelasticity, which can bond the positive and negative electrode sheets and the battery ceramic separator well at room temperature after conventional pressing. In addition, the hard core layer has a large particle size, which makes it less prone to deformation after pressing, and less likely to cause the binder to clog the separator. The large particle size of the hard core layer is also conducive to leaving gaps between the binders, thereby providing a buffer space for the expansion of the electrodes or separator after being immersed in the electrolyte, and improving the performance of the lithium battery.

[0047] Preferably, the mass ratio of the core layer to the shell layer in the lithium battery ceramic separator adhesive provided in this application is 1:1 to 2. When the mass ratio of the core layer to the shell layer is low, such as 1:0.5, the shell layer does not completely cover the core layer. After pressing, some positions where the lithium battery ceramic separator adhesive contacts the electrode sheet and the separator are without the shell layer, leaving the core layer exposed. Since the core layer is a styrene-based polymer, the bonding effect is poor. Therefore, by limiting the mass ratio of the core layer to the shell layer in the lithium battery ceramic separator adhesive to 1:1 to 2, this application can improve the bonding effect of the adhesive on the electrode sheet and the separator.

[0048] Preferably, the polymer monomers in the shell polymer of the lithium battery ceramic separator adhesive provided in this application include acrylate and alkyl acrylate. The alkyl acrylate grafted with alkyl has a higher glass transition temperature, which can easily lead to a poor shell bonding effect. In this application, the mass ratio of alkyl acrylate to the acrylate is 1:1 to 3. The mass percentage of alkyl acrylate is relatively low, which is beneficial to improving the bonding effect. Preferably, in this application, the alkyl acrylate is selected from methacrylate, the acrylate is selected from butyl acrylate, and the mass ratio of methacrylate to butyl acrylate is 8:17.

[0049] Example 2

[0050] This embodiment provides a method for preparing the lithium battery ceramic separator binder described in Example 1. The preparation method includes the preparation steps of the core layer styrene polymer and the preparation steps of the lithium battery ceramic separator binder.

[0051] The preparation steps of the core-layer styrene polymer include: adding 320g of anhydrous ethanol and 80g of deionized water, along with 20g of polyvinylpyrrolidone (PVP) as a dispersant and stabilizer, to a reactor equipped with a thermometer, nitrogen inlet, reflux device, and stirring device. The mixture is stirred and dissolved at room temperature, followed by the addition of 100g of styrene monomer. N2 is then introduced, and the temperature is raised to 70°C. After reaching 70°C, azobisisobutyronitrile (AIBN) initiator is rapidly added, and the polymerization reaction is continued at 70°C for 12 hours. After the reaction is complete, the temperature is lowered to room temperature to obtain a dispersion containing the core-layer styrene polymer. The particle size of the core-layer styrene polymer in the dispersion is approximately 1.5µm, and the phenyl groups contained in the core-layer styrene polymer result in "hard-core" microspheres.

[0052] The preparation steps of the lithium battery ceramic separator binder include adding 130g of a dispersion of a styrene-based polymer containing a core layer, 154g of deionized water as solvent, 1.25g of polyvinylpyrrolidone as a dispersion stabilizer, and 0.25g of sodium dodecyl sulfate as an emulsifier to a reaction vessel. The mixture is stirred at room temperature for 5–6 hours, then heated to 65°C and deoxygenated by purging with N2. Additionally, 12g of alkyl acrylate monomer methyl methacrylate, 13g of acrylate monomer butyl acrylate, and 0.13g of azobisisobutyronitrile (AIB) initiator are added. After mixing and dissolving at room temperature, the mixture is added to the reactor in one go. The reactor is kept at 65°C for 6-7 hours, then heated to 75°C and kept at 75°C for 3 hours. After the reaction is complete, the mixture is cooled to room temperature, and the reaction solution is filtered. The filtrate is collected to obtain a lithium battery ceramic separator adhesive with a core layer of styrene polymer and a shell layer of polyacrylate. The particle size of the lithium battery ceramic separator adhesive is about 1.8 μm. The polyacrylate shell has a low glass transition temperature, good viscoelasticity, and a soft texture. The lithium battery ceramic separator adhesive is a "hard core, soft shell" structure adhesive.

[0053] Example 3

[0054] This embodiment provides a preparation method for the lithium battery ceramic separator binder described in Example 1. The difference between the preparation method and Example 2 is that the mass of the alkyl acrylate monomer methyl methacrylate is 10g and the mass of the acrylate monomer butyl acrylate is 15g.

[0055] Example 4

[0056] This embodiment provides a method for preparing the lithium battery ceramic separator binder described in Example 1. The difference between the preparation method and Example 2 is that the mass of the alkyl acrylate monomer methyl methacrylate is 8g and the mass of the acrylate monomer butyl acrylate is 17g.

[0057] Example 5

[0058] This embodiment provides a method for preparing the lithium battery ceramic separator binder described in Example 1. The difference between the preparation method and Example 2 is that the mass of the dispersion of the core layer styrene polymer added is 86g, and the mass of the solvent deionized water added is 166g.

[0059] Comparative Example 1

[0060] This comparative example provides a method for preparing a ceramic separator binder for lithium batteries. The difference between this method and Example 2 is that the mass of the alkyl acrylate monomer methyl methacrylate is 17g and the mass of the acrylate monomer butyl acrylate is 8g.

[0061] Comparative Example 2

[0062] This comparative example provides a method for preparing a lithium-ion battery ceramic separator binder. The difference between this method and Example 2 lies in the preparation steps. In this comparative example, the preparation steps include adding 130g of a dispersion of a styrene-based polymer containing a core layer, adding 107g of deionized water as solvent, then adding 0.63g of polyvinylpyrrolidone as a dispersion stabilizer and 0.13g of sodium dodecyl sulfate as an emulsifier. The mixture is stirred at room temperature for 5-6 hours, then heated to 65°C and deoxygenated by passing N2 through the reactor. The alkyl acrylate monomer... 6g of methyl methacrylate and 6.5g of butyl acrylate monomer, along with 0.07g of azobisisobutyronitrile (AIBN) initiator, were mixed and dissolved at room temperature and then added to a reaction vessel in one go. The mixture was kept at 65℃ for 6-7 hours, then heated to 75℃ and kept at 75℃ for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the filtrate was collected to obtain a lithium battery ceramic separator binder with a styrene-based polymer core and a polyacrylate shell. The particle size of the lithium battery ceramic separator binder was approximately 1.5µm. The polyacrylate shell did not completely encapsulate the core layer, and some of the styrene-based polymer in the core layer was exposed.

[0063] Example 6

[0064] This embodiment provides a lithium battery, including a lithium battery ceramic separator, a positive electrode, a negative electrode, the lithium battery ceramic separator binder provided in Examples 2-5, and an electrolyte;

[0065] The positive electrode and the negative electrode are adhered to both sides of the lithium battery ceramic separator using the lithium battery ceramic separator adhesive provided in Examples 2-5.

[0066] The lithium battery ceramic separator, positive electrode, negative electrode, and the lithium battery ceramic separator binder provided in Examples 2-5 are impregnated in the electrolyte.

[0067] The lithium battery provided in this embodiment uses a lithium battery ceramic separator adhesive with excellent bonding strength at room temperature. Therefore, after the positive and negative electrodes are adhered to the lithium battery ceramic separator by the adhesive, the displacement of the electrode and separator can be improved, and the probability of short circuit caused by direct contact between the positive and negative electrodes can be reduced. At the same time, compared with polyvinylidene fluoride (PVDF) which needs to be dissolved in organic solvents such as N-methylpyrrolidone, the amount of organic solvent used can be reduced, making it more green and environmentally friendly.

[0068] The lithium batteries provided in this embodiment are not limited to power lithium batteries used in automobiles, but also include energy storage lithium batteries used in wind and solar power plants, as well as lithium batteries used in electronic devices such as watches, mobile phones, tablets, and laptops.

[0069] Test Example 1

[0070] The performance of the lithium battery ceramic separator adhesives provided in Examples 2-5 and Comparative Examples 1-2 of this application was tested, including particle size testing and peel strength testing (viscosity testing).

[0071] The particle size test involved measuring the average particle size of the lithium-ion battery ceramic membrane binder provided in Example 1 and Comparative Example 2. The test procedure involved adding the lithium-ion battery ceramic membrane binder dropwise into the test cell of a TopSizer laser particle size analyzer using distilled water as the mobile phase, and then determining the average particle size of the polymer-modified lithium-ion battery ceramic membrane binder. The results are as follows: Figure 1-2 As shown.

[0072] The peel strength test (viscosity test) was conducted using the lithium battery ceramic separator adhesive provided in Examples 2-5 and Comparative Examples 1-2. The adhesive was uniformly coated onto the surface of the ceramic separator and dried at 60°C to obtain a ceramic separator with an adhesive coating. This separator was then bonded to the coated surface of the electrode sheet. Subsequently, the peel strength between the electrode sheet and the separator was tested under a pressure of 1 MPa at room temperature for 15 s. The peel strength test (viscosity test) procedure was performed according to the national standard GB / T 2792-2014 "Test Method for Peel Strength of Adhesive Tapes". The 180° peel strength between the separator and the electrode sheet at room temperature was tested. The peel strength test (viscosity test) results are shown in Table 1.

[0073]

[0074] Table 1

[0075] As can be seen from Table 1, the polyacrylate copolymer of acrylate and alkyl acrylate in the lithium battery ceramic separator adhesive provided in Examples 2-5 has a glass transition temperature that allows the positive and negative electrode sheets and the battery ceramic separator to be well bonded at room temperature after conventional pressing. The peel strength between the positive and negative electrode sheets and the battery ceramic separator is about 8.3 to 13.3 N / m, which is high. This indicates that after the positive and negative electrode sheets and the battery ceramic separator are pressed and bonded at room temperature, the positive and negative electrode sheets and the battery ceramic separator provided in this application are difficult to peel off and move, and the bonding performance is excellent. This solves the technical problem in the prior art that the bonding effect of lithium battery ceramic separator adhesive at room temperature is not good and the electrode sheets and separator are easy to shift.

[0076] The peel strength of the lithium-ion battery ceramic separator adhesive provided in Examples 2-4 shows that adjusting the mass ratio of polymeric monomers acrylate and alkyl acrylate in the shell layer, i.e., increasing the mass of shell layer monomer acrylate and decreasing the mass of monomer alkyl acrylate, can improve the bonding strength of the lithium-ion battery ceramic separator adhesive. Furthermore, the peel strength of the lithium-ion battery ceramic separator adhesive provided in Comparative Example 1 shows that decreasing the mass of shell layer monomer acrylate and increasing the mass of monomer alkyl acrylate may cause the lithium-ion battery ceramic separator adhesive to lose its bonding effect. This is caused by the excessively high glass transition temperature of the shell layer due to the increased mass of alkyl acrylate. Combined with the peel strength test (viscosity test) results, it can be determined that when the mass ratio of methacrylate to butyl acrylate in the shell layer is 8:17, the peel strength (viscosity) performance of the lithium-ion battery ceramic separator adhesive is excellent.

[0077] From Examples 5 and 1, it can be determined that, compared with the lithium battery ceramic separator adhesive provided in Example 1, Example 5 reduces the mass of the styrene polymer core layer in the lithium battery ceramic separator adhesive. The results show that the peel strength of the lithium battery ceramic separators provided in Examples 1 and 5 is similar, and their bonding performance is almost identical. This indicates that the core layer of the lithium battery ceramic separator adhesive has no effect on the bonding performance. The shell layer in the lithium battery ceramic separator adhesive that bonds to the lithium battery electrode and separator is a surface bond. The hard core layer is not easily deformed after the pressing process, which can reduce the possibility of adhesive clogging the separator and allows for expansion after the electrode or separator is immersed in the electrolyte. Providing buffer space improves lithium battery performance. Further analysis of the lithium battery ceramic separator adhesive test results provided in Comparative Example 2 confirms that when the mass of the shell polyacrylate in the lithium battery ceramic separator adhesive is reduced—that is, when the shell mass is low—it cannot encapsulate the core layer, resulting in core layer exposure and poor core layer adhesion. This leads to a decrease in the peel strength (viscosity) performance of the lithium battery ceramic separator adhesive. Combined with the peel strength (viscosity) test results, it can be determined that when the mass ratio of the core layer to the shell layer is 1:1 to 2, the peel strength (viscosity) performance of the lithium battery ceramic separator adhesive is excellent.

[0078] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A lithium battery, characterized in that, This includes lithium-ion battery ceramic separators, positive electrodes, negative electrodes, lithium-ion battery ceramic separator binders, and electrolytes. The positive electrode and the negative electrode are adhered to both sides of the lithium battery ceramic separator by the lithium battery ceramic separator adhesive; The lithium battery ceramic separator, the positive electrode, the negative electrode, and the lithium battery ceramic separator binder are immersed in the electrolyte; The lithium battery ceramic separator adhesive includes a core layer and a shell layer, wherein the mass ratio of the core layer to the shell layer is 1:

1. The core layer is a styrene polymer, and the styrene monomer of the styrene polymer is selected from styrene and / or divinylbenzene; The shell layer is polyacrylate, and the monomers of the polyacrylate are methyl methacrylate and butyl acrylate, wherein the mass ratio of methyl methacrylate to butyl acrylate is 8:

17. The particle size of the lithium battery ceramic separator binder is 1-3 micrometers.

2. A lithium battery according to claim 1, characterized in that, The particle size of the lithium battery ceramic separator binder is 1.5~2 micrometers.

3. A lithium battery according to any one of claims 1-2, characterized in that, The preparation method of the lithium battery ceramic separator binder includes the following steps: Step S1: After mixing styrene monomers, initiators and solvents, a core-layer polymerization reaction is carried out to obtain a styrene polymer dispersion. Step S2: The styrene polymer dispersion, butyl acrylate, methyl methacrylate, dispersion stabilizer polyvinylpyrrolidone, initiator, emulsifier and solvent water are subjected to a shell polymerization reaction to obtain a lithium battery ceramic separator binder dispersion.

4. A lithium battery according to claim 3, characterized in that, In step S1, the temperature of the core-layer polymerization reaction is 65~75℃, and the time is 12h~24h; In step S2, the temperature of the shell polymerization reaction is 60~80℃ and the time is 9h~15h.

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