Solid electrolyte, preparation method thereof, lithium ion battery and electric equipment

Abstract

The invention provides a solid electrolyte, a preparation method thereof, a lithium ion battery and electric equipment. The preparation raw materials of the solid electrolyte comprise the polyfunctionality monomer with the structure shown in the formula (1), when the solid electrolyte is formed through in-situ curing in electrolyte, the functionality of the polyfunctionality monomer is high, the polyfunctionality monomer can form a highly-crosslinked polymer network structure in the polymerization reaction process, and therefore the solid electrolyte is obtained. The structure endows the polymer with excellent mechanical properties, such as high strength and high modulus, so that the polymer can maintain better structural stability when bearing external stress, the high voltage resistance of the polymer structure is improved, the solid electrolyte is not easy to decompose or crack and lose efficacy, the structural damage of the electrolyte material in the charging and discharging process is inhibited, and the service life of the electrolyte material is prolonged. The electrochemical stability of the electrolyte material is maintained, so that the service life and the safety of the battery are prolonged, and the charge-discharge performance of the battery is maintained.

Description

[0001] This application is a divisional application. The original application number is 202510907925.2, the application date is July 2, 2025, and the invention title is: A multifunctional monomer and its preparation method, solid electrolyte, lithium-ion battery and electrical equipment. Technical Field

[0002] This application belongs to the field of battery technology, and in particular relates to a solid electrolyte, its preparation method, lithium-ion batteries, and electrical equipment. Background Technology

[0003] Solid-state batteries, as a cutting-edge battery technology, have garnered significant attention in recent years due to their high energy density and high safety. Solid-state batteries use solid electrolytes instead of the liquid electrolytes found in traditional lithium-ion batteries, which greatly reduces the risk of thermal runaway and combustion. The energy density of solid-state batteries is directly proportional to their operating voltage; therefore, improving the battery's high-voltage tolerance directly increases its energy density, which is of great significance for applications requiring high-energy-density batteries, such as electric vehicles and aerospace.

[0004] However, in related technologies, solid electrolytes are prone to decomposition under high voltage conditions, which reduces the overall performance of the battery and needs further improvement. Summary of the Invention

[0005] Embodiments of this application provide a solid electrolyte, a method for its preparation, a lithium-ion battery, and an electrical device, aimed at solving the aforementioned technical problems.

[0006] In a first aspect, embodiments of this application provide a solid electrolyte, which is formed by solidifying a multifunctional monomer in an electrolyte. The multifunctional monomer has a structure as shown in formula (1): Equation (1).

[0007] In some embodiments, the conductivity of the solid electrolyte is 4 mS / cm-10 mS / cm.

[0008] In some embodiments, the multifunctional monomer is obtained by reacting 1,4-dimethylenecyclohexane diisocyanate with a trifunctional acrylate compound.

[0009] In some embodiments, the electrolyte includes a solvent, a lithium salt, and / or additives; The solvent has a mass percentage of 79%-89% in the electrolyte; The lithium salt in the electrolyte has a mass percentage of 10%-20%; The additive is present in the electrolyte at a mass percentage of 1%-5%.

[0010] A second aspect of this application provides a method for preparing the solid electrolyte, the method comprising: A prepolymer solution is provided, the prepolymer solution comprising an electrolyte and a multifunctional monomer; The multifunctional monomers in the prepolymer solution undergo an in-situ solidification reaction to obtain the solid electrolyte; The multifunctional monomer is a multifunctional monomer with the structure shown in formula (1).

[0011] In some embodiments, the curing temperature of the curing reaction is 40℃-80℃, and / or the curing time is 12h-72h; and / or The viscosity of the prepolymer at room temperature is 2 mPa·s-8 mPa·s; and / or The prepolymer solution also includes an initiator.

[0012] In some embodiments, the multifunctional monomer is present in the prepolymer solution at a mass percentage of 1%-5%; and / or The electrolyte comprises 94%-98.997% by mass in the prepolymer solution; and / or The electrolyte includes a solvent, a lithium salt, and / or additives; and / or The initiator in the prepolymer solution has a mass percentage of 0.003%-0.15%; and / or The initiator includes at least one of azo initiators and peroxide initiators.

[0013] In some embodiments, the solvent includes at least one of carbonate solvents and carboxylic acid ester solvents; and / or The solvent has a mass percentage of 79%-89% in the electrolyte; and / or The lithium salt comprises at least one of lithium hexafluorophosphate, lithium perchlorate, lithium difluorooxalate borate, lithium trifluoromethanesulfonylimide, lithium difluorosulfonylimide, lithium diacetate borate, lithium tetrafluoroborate, and lithium difluorophosphate; and / or The lithium salt has a mass percentage of 10%-20% in the electrolyte; and / or The additive includes at least one of propanesulfonyl lactone, vinyl sulfate, and 1,3,6-hexanetrionitrile; and / or The additive is present in the electrolyte at a mass percentage of 1%-5%.

[0014] Thirdly, embodiments of this application provide a lithium-ion battery, including the solid electrolyte as described above, or a solid electrolyte prepared using the method described above.

[0015] Fourthly, embodiments of this application provide an electrical device, including the solid electrolyte as described above, or a solid electrolyte prepared by the method described above, or including a lithium-ion battery as described above.

[0016] The beneficial effects of the embodiments of this application are as follows: The multifunctional monomer of this application has a structure as shown in formula (1). When the multifunctional monomer is used as a reactant raw material and solidified in situ in the electrolyte to form a solid electrolyte, firstly, the acrylate group is a reactive functional group, and the number of acrylate groups is 6. The multifunctional monomer has a high degree of functionality. During the polymerization reaction, the multifunctional monomer can form a highly cross-linked polymer network structure. The highly cross-linked polymer network structure is like a tightly woven net. The molecular chains are intertwined and fixed by a large number of chemical bonds, which greatly restricts the movement of the molecular chains. This structure endows the polymer with excellent mechanical properties, such as high strength and high modulus, so that it can maintain good structural stability when subjected to external stress. It also improves the high voltage resistance of the polymer structure. The solid electrolyte is not easy to decompose or break down and fail. It inhibits the structural damage of the electrolyte material during the charging and discharging process, maintains the electrochemical stability of the electrolyte material, thereby extending the battery's service life and safety, and maintaining the battery's charging and discharging performance.

[0017] Secondly, the urethane groups in the backbone of the multifunctional monomer endow the monomer molecules with strong polarity, enabling the multifunctional monomer to interact with electrolyte solvent molecules, thereby improving conductivity. Moreover, the urethane groups have strong chemical bond energy, which can enhance the structural stability of the solid electrolyte through interactions such as forming hydrogen bonds. This enhanced structural stability helps the solid electrolyte maintain its shape and integrity under high pressure, preventing performance degradation due to structural damage.

[0018] Thirdly, multifunctional monomers are polymerized to form cross-linked polymers, which are combined with electrolytes to form solid electrolytes. Solid electrolytes contain urethane groups, and the nitrogen atoms and carbonyl oxygen atoms in the urethane groups can form strong interactions with conductive ions. This interaction helps to stabilize the existence form of conductive ions, reduce the migration and aggregation of conductive ions under high voltage, and thus improve the high voltage resistance of solid electrolytes.

[0019] Fourthly, after the polymerization of multifunctional monomers, the two ends of the urethane group on the main chain are bonded with large ester side groups. The nitrogen atom and carbonyl oxygen atom in the urethane group have lone pairs of electrons, which makes the urethane group negatively charged as a whole, thus giving the urethane group strong polarity. This allows the urethane group to enhance the electron cloud density of the ester side groups it is connected to, lowering the HOMO energy level (highest occupied molecular orbital energy level) of the cross-linked polymer. This makes it more difficult for the cross-linked polymer to lose electrons, requiring more external energy and higher voltage to be oxidized. Therefore, the large ester side groups at both ends of the urethane group act as a "protective umbrella," providing protection for the polymer molecular chain to better resist oxidation under high voltage, reduce oxidative decomposition or side reactions of the polymer, reduce the risk of oxidative degradation of the solid electrolyte under high voltage environment, and thus improve the high voltage resistance of the solid electrolyte. Attached Figure Description

[0020] To more clearly illustrate the solutions in this application or the prior art, the drawings used in the description of the 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 based on these drawings without creative effort. Figure 1 The infrared spectrum of the multifunctional monomer of Embodiment 1 of this application; Figure 2 This is a scan curve of the electrochemical stability window of the solid electrolyte in Example 1 of this application; Figure 3 This is a high-voltage cycling curve of the solid-state pouch cell of Example 1 and Comparative Example 1 of this application. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. 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. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0022] In related technologies, solid electrolytes are prone to decomposition under high voltage conditions, which reduces the overall performance of the battery and needs further improvement.

[0023] This application provides a multifunctional monomer for use in solid electrolytes. The multifunctional monomer has a structure as shown in formula (1): Equation (1); R1, R2, R3, R4, R5, and R6 are each independently selected from acrylate groups or hydroxyl groups, and at most one of R1, R2, R3, R4, R5, and R6 is a hydroxyl group. R7 is selected from alkyl or cycloalkyl groups.

[0024] In this embodiment, the multifunctional monomer of this application has a structure as shown in formula (1). When the multifunctional monomer is used as a reactant raw material to solidify in situ in the electrolyte to form a solid electrolyte, firstly, the acrylate group is a reactive functional group, and the number of acrylate groups is at least 5. The multifunctional monomer has a high degree of functionality. During the polymerization reaction, the multifunctional monomer can form a highly cross-linked polymer network structure. The highly cross-linked polymer network structure is like a tightly woven net. The molecular chains are intertwined and fixed by a large number of chemical bonds, which greatly restricts the movement of the molecular chains. This structure endows the polymer with excellent mechanical properties, such as high strength and high modulus, so that it can maintain good structural stability when subjected to external stress. It also improves the high voltage resistance of the polymer structure. The solid electrolyte is not easy to decompose or break down and fail. It inhibits the structural damage of the electrolyte material during the charging and discharging process, maintains the electrochemical stability of the electrolyte material, thereby extending the battery's service life and safety, and maintaining the battery's charging and discharging performance.

[0025] Secondly, the urethane groups in the backbone of the multifunctional monomer endow the monomer molecules with strong polarity, enabling the multifunctional monomer to interact with electrolyte solvent molecules, thereby improving conductivity. Moreover, the urethane groups have strong chemical bond energy, which can enhance the structural stability of the solid electrolyte through interactions such as forming hydrogen bonds. This enhanced structural stability helps the solid electrolyte maintain its shape and integrity under high pressure, preventing performance degradation due to structural damage.

[0026] Thirdly, multifunctional monomers are polymerized to form cross-linked polymers, which are combined with electrolytes to form solid electrolytes. Solid electrolytes contain urethane groups, and the nitrogen atoms and carbonyl oxygen atoms in the urethane groups can form strong interactions with conductive ions. This interaction helps to stabilize the existence form of conductive ions, reduce the migration and aggregation of conductive ions under high voltage, and thus improve the high voltage resistance of solid electrolytes.

[0027] Fourthly, after the polymerization of multifunctional monomers, the two ends of the urethane group on the main chain are bonded with large ester side groups. The nitrogen atom and carbonyl oxygen atom in the urethane group have lone pairs of electrons, which makes the urethane group negatively charged as a whole, thus giving the urethane group strong polarity. This allows the urethane group to enhance the electron cloud density of the ester side groups it is connected to, lowering the HOMO energy level (highest occupied molecular orbital energy level) of the cross-linked polymer. This makes it more difficult for the cross-linked polymer to lose electrons, requiring more external energy and higher voltage to be oxidized. Therefore, the large ester side groups at both ends of the urethane group act as a "protective umbrella," providing protection for the polymer molecular chain to better resist oxidation under high voltage, reduce oxidative decomposition or side reactions of the polymer, reduce the risk of oxidative degradation of the solid electrolyte under high voltage environment, and thus improve the high voltage resistance of the solid electrolyte.

[0028] Fifthly, after the polymerization of multifunctional monomers, both ends of the urethane groups on the main chain are bonded with large ester side groups. Specific intermolecular interactions exist between the urethane groups and these large ester side groups. These interactions prevent the polymer from generating free ionic fragment groups under high voltage (>4.5V). Solid electrolytes can match high-voltage cathodes, exhibiting strong high-voltage resistance. Taking lithium cobalt oxide as an example, during charging, lithium cobalt oxide delithiates to form high-valence tetravalent cobalt ions. These high-valence cobalt ions have high chemical activity and easily react with surrounding substances, such as solvent molecules, leading to instability on the surface structure of the cathode active particles. The substances surrounding the high-valence cobalt ions are easily oxidized and decomposed into ionic fragments. The urethane and ester side groups in the polymer molecular chain can form a good synergistic complexation with tetravalent cobalt ions, "fixing" cobalt ions on the surface of the positive electrode active particles through coordination chemistry. This effectively stabilizes the metal ions on the surface of the positive electrode active particles, reduces the dissolution and migration of metal ions, and improves the stability of the polymer molecular chain under high voltage fields. Furthermore, the intermolecular interaction between the urethane groups and the larger ester side groups significantly enhances the polymer molecular chain's complexation ability with lithium ions and solvents. Under high voltage, the distribution of lithium ions is easily affected by the electric field and chemical reactions, leading to local aggregation. However, by forming stable complexes with lithium ions and solvents, the polymer molecular chain can uniformly disperse lithium ions, reducing local aggregation and enabling uniform and efficient transport of lithium ions in the polymer electrolyte. This improves the high-voltage resistance of the polymer electrolyte and extends the battery's lifespan.

[0029] In one embodiment, R7 has a structure as shown in formula (2) or formula (3): Equation (2); Equation (3); Where n1 is selected from integers from 0 to 10, n2 is selected from integers from 0 to 10, n3 is selected from integers from 0 to 3, and the sum of n1 and n2 is between 1 and 10; n4 is selected from integers from 0 to 5, n5 is selected from integers from 0 to 5, n6 is selected from integers from 0 to 3, n7 is selected from integers from 0 to 3, and the sum of n4 and n5 is between 1 and 10.

[0030] In this embodiment, the sum of n1 and n2 is between 1 and 10, and / or the sum of n4 and n5 is between 1 and 10. This ensures that the volume and molecular weight of the multifunctional monomer are not too large, and that the viscosity of the prepolymer solution is not too high when the multifunctional monomer is added to the prepolymer solution, which is beneficial for the prepolymer solution to wet the electrode.

[0031] In one embodiment, n1 is selected from an integer between 3 and 10, n2 is selected from an integer between 0 and 2, n3 is selected from an integer between 0 and 1, and the sum of n1 and n2 is between 3 and 10.

[0032] In one embodiment, n4 is selected from an integer between 0 and 2, n5 is selected from an integer between 0 and 2, n6 is selected from an integer between 0 and 1, n7 is selected from an integer between 0 and 1, and the sum of n4 and n5 is 4.

[0033] In one embodiment, the multifunctional monomer includes at least one of the following compounds: , , , , , , , .

[0034] The multifunctional monomers employing the above structure, where R1, R2, R3, R4, R5, and R6 are each independently selected from acrylate groups or hydroxyl groups, with a functionality number between 5 and 6, enable efficient cross-linking, enhancing the structural stability of the polymer and thus improving the high-voltage stability of the solid electrolyte. Furthermore, the high functionality allows the multifunctional monomers to polymerize at relatively low concentrations, forming a polymer network and resulting in good conductivity of the solid electrolyte. The alkyl or cycloalkyl structure of R7 group, with controlled values ​​of n1 to n6, ensures that the volume and molecular weight of the multifunctional monomers are not excessively large. This prevents excessive viscosity of the prepolymer solution when added, facilitating electrode wetting. Additionally, the aforementioned multifunctional monomers possess a basically symmetrical molecular structure, which facilitates more efficient proximity and reaction between monomer molecules, promoting cross-linking and improving material structural stability. Therefore, the aforementioned multifunctional monomers exhibit better performance in terms of prepolymer viscosity, solid electrolyte conductivity, and high voltage resistance of solid electrolyte, and show superior performance in high voltage cycle performance of batteries.

[0035] In one embodiment, the functionality number of the multifunctional monomer is between 5 and 6. Optionally, the functionality number of the multifunctional monomer is 5 or 6. Functionality refers to the number of functional groups in a monomer molecule that can participate in the reaction, which is directly related to the reactivity of the reactants and the structural characteristics of the products. Generally speaking, the higher the functionality number, the more active sites the monomer molecule has in the reaction, the faster the reaction rate, the greater the probability of the monomer molecule participating in the polymerization reaction, and the higher the degree of crosslinking of the resulting polymer. When the functionality number of the multifunctional monomer is less than 5, the structural stability of the polymer is easily reduced, and the solid electrolyte is prone to decomposition. When the functionality number of the multifunctional monomer is greater than 6, it is easy to cause the crosslinking points to be too dense, the molecular pores constructed by the polymer molecular chains are small, which is not conducive to electrolyte absorption, nor to the shuttle and conduction of conductive ions between molecular pores, and also seriously hinders the flexible movement of molecular chains, resulting in a significant decrease in the flexibility of the polymer, making it stiff and brittle. At the same time, the tightly crosslinked network structure also restricts the transport of ions inside the polymer, making the ion transport performance of the solid electrolyte worse.

[0036] In this embodiment, setting the functionality of the multifunctional monomer between 5 and 6 ensures that the generated polymer has a suitable degree of crosslinking. Simultaneously, the urethane groups on the polyfunctional monomer's dry chain impart strong flexibility to the monomer molecule. The nitrogen and carbonyl oxygen atoms in the urethane groups have high polarity, and the urethane groups can contribute some charge and reduce steric hindrance. Furthermore, the urethane groups can generate specific intermolecular interactions with the large-volume ester side groups at both ends. This interaction lowers the energy barrier for the rotation and peristalsis of the polymer molecular chain backbone, allowing the polymer molecular chain to rotate and peristalse to a certain extent under relatively small external forces, thereby improving the mobility of the polymer molecular chain. This increased flexibility acts as a "lubricant" for the originally rigid polymer network structure, enabling the polymer molecular chain to move freely to a certain extent. This effectively offsets the decrease in flexibility and reduced porosity of the polymer molecular chain caused by high crosslinking of side groups, and enhances the polymer molecular chain's ability to absorb and dissolve electrolytes and lithium salts. Meanwhile, the enhanced mobility of polymer molecular chains by urethane groups indirectly improves ion transport performance. The enhanced mobility of polymer molecular chains opens up smoother channels for ion transport within the polymer, allowing ions to migrate more freely between polymer molecular chains and improving the ion transport efficiency of solid electrolytes.

[0037] In one embodiment, the multifunctional monomer has a symmetrical molecular structure. In this embodiment, the highly functional and structurally symmetrical multifunctional monomer exhibits a significant tendency to form a highly cross-linked polymer network structure during the polymerization reaction. A highly functional monomer means that each monomer molecule possesses multiple active sites, which can rapidly and extensively react with adjacent monomer molecules during polymerization to form multiple chemical bonds. The symmetrical structure allows the multifunctional monomer molecules to arrange themselves in a spatially regular manner. During polymerization, this regularity helps monomer molecules approach each other more efficiently and react, thereby promoting the formation of cross-linked structures.

[0038] The high functionality, structural symmetry, and urethane groups in multifunctional monomers each play a unique role in the polymer, and they also work synergistically to fully leverage their advantages. This allows for the preparation of solid electrolyte materials that combine excellent structural stability, high voltage resistance, good flexibility, and efficient ion transport performance, thus meeting the battery's demand for high-performance materials.

[0039] This application also provides a method for preparing a multifunctional monomer, the method comprising: S1 provides trifunctional acrylate monomers and diisocyanate compounds; S2. React trifunctional acrylate monomers with diisocyanate compounds to obtain polyfunctional monomers; Among them, the multifunctional monomer has the structure shown in formula (1): Equation (1); R1, R2, R3, R4, R5, and R6 are each independently selected from acrylate groups or hydroxyl groups, and at most one of R1, R2, R3, R4, R5, and R6 is a hydroxyl group. R7 is selected from alkyl or cycloalkyl groups.

[0040] In this embodiment, a trifunctional acrylate monomer refers to a monomer with a functionality of 3, and all functional groups are acrylate groups.

[0041] In one embodiment, the molar ratio between the trifunctional acrylate monomer and the diisocyanate compound is 2:(1-1.1).

[0042] In one embodiment, the reaction temperature between the trifunctional acrylate monomer and the diisocyanate compound is 20°C-50°C.

[0043] In one embodiment, the structural formula of the diisocyanate compound is shown in formula (4): O=C=N-R7-N=C=O Equation (4); R7 is selected from alkyl or cycloalkyl groups.

[0044] In one embodiment, the method for preparing the trifunctional acrylate monomer includes: S11, provides pentaerythritol and acrylic acid; S12 causes pentaerythritol and acrylic acid to undergo an esterification reaction under catalytic conditions to generate trifunctional acrylate monomers.

[0045] In one embodiment, the molar ratio between pentaerythritol and acrylic acid is 1:(3-3.1).

[0046] In one embodiment, the esterification reaction temperature is 75°C-80°C.

[0047] In one specific embodiment, the preparation method of the multifunctional monomer is as follows: S111. Add pentaerythritol, acrylic acid, p-toluenesulfonic acid, copper chloride, and cyclohexane to the flask; S112. While introducing oxygen-containing gas (5% oxygen by volume and 95% nitrogen by volume) into the flask, carry out a dehydration esterification reaction at 75-80 °C for 12 hours. During the reaction, the generated water is discharged outside the system using a distillation tube. After the reactions in steps S113 and S112 are completed, n-propyl acetate and distilled water are added to the reaction solution for dilution. The mixture is stirred thoroughly and allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer). The lower aqueous phase is removed. Then, 20 wt% sodium hydroxide aqueous solution is added to the organic solvent phase to neutralize the acid components contained in the organic solvent phase. The mixture is allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer). The lower aqueous phase is removed and the organic solvent phase is recovered. Then, distilled water is added to the recovered organic solvent phase for washing. The mixture is allowed to stand to remove the separated aqueous phase (lower layer) and recover the upper organic solvent phase. S114. Dry air is introduced into the organic solvent phase that is finally recovered in step S113, and the solvent is removed by distillation by heating to 70°C under reduced pressure, thereby obtaining trifunctional acrylate. S115. Take the above trifunctional acrylate, add a diisocyanate compound, stir and react at room temperature for 5 hours, then stir and react at 50°C for 2 hours to obtain a multifunctional monomer.

[0048] In this embodiment, the general reaction formula for the preparation of multifunctional monomers is: .

[0049] In this embodiment, the preparation method of multifunctional monomers is efficient and simple, and has the characteristics of low energy consumption, no pollution and easy production.

[0050] This application also provides a solid electrolyte, which is formed by solidifying a multifunctional monomer in an electrolyte; the multifunctional monomer is the multifunctional monomer described above or the multifunctional monomer obtained by the preparation method described above.

[0051] In one embodiment, the conductivity of the solid electrolyte is 4 mS / cm-10 mS / cm. Because the polymer molecular backbone of the solid electrolyte contains urethane groups, which have a high dielectric constant, this means that under an electric field, the group can more effectively conduct charge, avoiding localized charge accumulation. In high-voltage environments, this efficient ion conduction helps maintain the stability of the electrolyte while simultaneously improving its conductivity.

[0052] This application also provides a method for preparing a solid electrolyte, the method comprising: S21. Provide a prepolymer solution, which includes an electrolyte and a multifunctional monomer; S22. In-situ solidification reaction of multifunctional monomers in prepolymer solution is carried out to obtain solid electrolyte; The multifunctional monomer used is either the multifunctional monomer described above or the multifunctional monomer prepared by the method described above.

[0053] In one embodiment, the viscosity of the prepolymer solution at room temperature is 2 mPa·s to 8 mPa·s. Optionally, the viscosity of the prepolymer solution at room temperature can be any one or any two of 2 mPa·s, 3 mPa·s, 5 mPa·s, 7 mPa·s, and 8 mPa·s, and is not limited herein. In this embodiment, the prepolymer solution has a low viscosity at room temperature. The low viscosity prepolymer solution has better flow properties, which allows it to better wet electrode pores and membrane pores, making it easier to form a uniform and stable gel structure and continuous ion channels in the battery, thereby improving the high-voltage resistance and ion transport performance of the solid electrolyte.

[0054] In one embodiment, the curing temperature of the curing reaction is 40°C-80°C, and / or the curing time is 12h-72h.

[0055] In one embodiment, the prepolymer liquid further includes an initiator that can initiate polymerization reactions between multifunctional monomers, thereby improving the efficiency of the polymerization reaction.

[0056] In one embodiment, the mass percentage of the initiator in the prepolymer solution is 0.003%-0.15%; optionally, the mass percentage of the initiator in the prepolymer solution can be any one or any two of 0.003%, 0.005%, 0.01%, 0.05%, 0.15%, etc., and is not limited herein.

[0057] In one embodiment, the initiator includes at least one of azo initiators and peroxide initiators. For example, the initiator may include at least one of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, benzoyl peroxide, and tert-butyl peroxide benzoate.

[0058] In one embodiment, the mass percentage of the multifunctional monomer in the prepolymer solution is 1%-5%. Optionally, the mass percentage of the multifunctional monomer in the prepolymer solution can be any one or any two of 1%, 2%, 3%, 4%, 5%, etc., and is not limited herein. In this embodiment, the multifunctional monomer is a highly functional monomer, where each function is a reaction site. The dense concentration of reaction sites endows the multifunctional monomer with high reactivity, enabling it to undergo polymerization at low concentrations to form a polymer network, thus giving the polymerized molecular chains good high-voltage resistance.

[0059] In this embodiment, when the mass percentage of multifunctional monomers in the prepolymer solution is less than 1%, the multifunctional monomers cannot be effectively solidified, resulting in a loose structure of the solid electrolyte and a decrease in the mechanical properties, ion transport properties, and high-voltage resistance of the solid electrolyte. When the mass percentage of multifunctional monomers in the prepolymer solution is greater than 5%, it easily leads to excessively high viscosity of the prepolymer solution, which is not conducive to the wetting of the battery electrodes by the prepolymer solution, resulting in a decrease in the electrochemical performance of the battery.

[0060] In one embodiment, the mass percentage of the electrolyte in the prepolymer solution is 94%-98.997%. Optionally, the mass percentage of the electrolyte in the prepolymer solution can be any one or any two of 94%, 95%, 96%, 97%, 98.997%, etc., and is not limited herein.

[0061] In one embodiment, the electrolyte includes a solvent, a lithium salt, and / or additives.

[0062] In one embodiment, the solvent has a mass percentage of 79%-89% in the electrolyte. Optionally, the solvent mass percentage in the electrolyte can be any one or any two of 79%, 82%, 84%, 86%, 89%, etc., and is not limited herein.

[0063] In one embodiment, the solvent includes at least one of carbonate solvents and carboxylic acid ester solvents. For example, the solvent may include at least one of propyl propionate, dimethyl carbonate, ethyl methyl carbonate, ethyl propionate, ethylene carbonate, and fluoroethylene carbonate. In this embodiment, the multifunctional monomer contains urethane groups, which can enhance the structural stability of the solid electrolyte by forming hydrogen bonds with the solvent. This enhanced structural stability helps the solid electrolyte maintain its structural integrity under high voltage, reducing battery performance degradation caused by solid electrolyte structural damage.

[0064] In one embodiment, the mass percentage of lithium salt in the electrolyte is 10%-20%; alternatively, the mass percentage of lithium salt in the electrolyte can be any one or any two of 10%, 12%, 14%, 16%, 20%, etc., and is not limited herein.

[0065] In one embodiment, the lithium salt includes at least one of lithium hexafluorophosphate, lithium perchlorate, lithium difluorooxalate borate, lithium trifluoromethanesulfonylimide, lithium difluorosulfonylimide, lithium diacetate borate, lithium tetrafluoroborate, and lithium difluorophosphate.

[0066] In one embodiment, the mass percentage of the additive in the electrolyte is 1%-5%. Optionally, the mass percentage of the additive in the electrolyte can be any one or any two of 1%, 2%, 3%, 4%, 5%, etc., and is not limited herein.

[0067] In one embodiment, the additive includes at least one selected from propane sulpholactone, vinyl sulfate, and 1,3,6-hexanetrionitrile.

[0068] This application also provides a lithium-ion battery, including the solid electrolyte as described above, or a solid electrolyte prepared by the method described above.

[0069] This application also provides an electrical device, including the solid electrolyte as described above, or a solid electrolyte prepared by the method described above, or including the lithium-ion battery as described above. In this embodiment, the type of electrical device is not limited, and the electrical device can be an automobile, a ship, a drone, a stationary power supply, a portable power supply, etc.

[0070] The present application will be further described below through specific embodiments. Unless otherwise specified, the experimental materials used in the following embodiments can be purchased from conventional biochemical reagent companies.

[0071] Example 1 A method for preparing a multifunctional monomer includes the following steps: (1) Add 1 mol pentaerythritol, 3 mol acrylic acid, 6 g p-toluenesulfonic acid, 0.2 g copper chloride and 38 g cyclohexane to the flask; (2) While introducing oxygen-containing gas (5% by volume of oxygen and 95% by volume of nitrogen) into the flask, carry out a dehydration esterification reaction at 75-80 °C for 12 hours. During the reaction, the generated water is discharged outside the system using a distillation tube. (3) After the reaction in step (2) is completed, 100g of n-propyl acetate and 8g of distilled water are added to the reaction solution for dilution. The solution is stirred thoroughly and allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer). The lower aqueous phase is removed. Then, 20wt% sodium hydroxide aqueous solution is added to the organic solvent phase to neutralize the acid components contained in the organic solvent phase. The solution is allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer). The lower aqueous phase is removed and the organic solvent phase is recovered. Then, distilled water is added to the recovered organic solvent phase for washing. The solution is allowed to stand to remove the separated aqueous phase (lower layer) and the upper organic solvent phase is recovered. (4) In the organic solvent phase finally recovered in step (3), dry air is introduced and the solvent is removed by distillation under reduced pressure and heated to 70°C to obtain trifunctional acrylate; (5) Take 1 mol of the above trifunctional acrylate, add 0.5 mol of 1,3-propanediisocyanate, stir at room temperature for 5 h, and then stir at 50 °C for 2 h to obtain a multifunctional monomer.

[0072] In this embodiment, the structural formula of the multifunctional monomer is: .

[0073] A method for preparing a lithium-ion battery includes the following steps: (6) Dissolve 3g of the multifunctional monomer prepared in this embodiment and 0.03g of azobisisobutyronitrile in 96.97g of electrolyte to obtain a prepolymer solution; wherein the electrolyte solution includes: 39.97g of propyl propionate, 12g of methyl ethyl carbonate, 14g of ethylene carbonate, 11g of fluoroethylene carbonate, 1g of propane sulpholol, 1g of ethylene sulfate, 2g of 1,3,6-hexanetrionitrile, 12g of lithium hexafluorophosphate, 3g of lithium difluorosulfonylimide, and 1g of lithium difluorophosphate; (7) In a dry room (relative humidity below 2%, dew point below -40 ºC), the prepolymer liquid is injected into the dry cell assembled from the positive electrode, negative electrode and separator at room temperature. It is pre-sealed with a heat sealer and left to stand at room temperature for 24 h. Then it is placed in a hot oven and slowly heated to 50 ℃ for 24 h. During the heating, the prepolymer liquid undergoes a solidification reaction inside the dry cell. Solid electrolyte is obtained through in-situ thermal solidification to prepare a lithium-ion battery.

[0074] Example 2 The main difference between Example 2 and Example 1 is: Replace 1,3-propanediisocyanate with hexamethylenediisocyanate, otherwise the same as in Example 1; In this embodiment, the structural formula of the multifunctional monomer is: .

[0075] Example 3 The main difference between Example 3 and Example 1 is: Replace 1,3-propanediisocyanate with 1,10-decanediisocyanate, otherwise the same as in Example 1; In this embodiment, the structural formula of the multifunctional monomer is: .

[0076] Example 4 The main difference between Example 4 and Example 1 is: Replace 1,3-propanediisocyanate with 1-methylbutane-1,4-diisocyanate, otherwise the same as in Example 1; In this embodiment, the structural formula of the multifunctional monomer is: .

[0077] Example 5 The main difference between Example 5 and Example 1 is: Replace 1,3-propanediisocyanate with 1,2-diethylpentane-1,5-diisocyanate, otherwise the same as in Example 1; In this embodiment, the structural formula of the multifunctional monomer is: .

[0078] Example 6 The main difference between Example 6 and Example 1 is: Replace 1,3-propanediisocyanate with 1,4-cyclohexanediisocyanate, otherwise the same as in Example 1; In this embodiment, the structural formula of the multifunctional monomer is: .

[0079] Example 7 The main difference between Example 7 and Example 1 is: Replace 1,3-propanediisocyanate with 1,4-dimethylenecyclohexanediisocyanate, otherwise the same as in Example 1; In this embodiment, the structural formula of the multifunctional monomer is: .

[0080] Example 8 The main difference between Example 8 and Example 1 is: The proportion of added raw materials was adjusted, namely, pentaerythritol (1 mol) and acrylic acid (3 mol) were added and heated to react to obtain trifunctional acrylates, and pentaerythritol (1 mol) and acrylic acid (2 mol) were added and heated to react to obtain difunctional acrylates. The above two acrylates and 1,3-propanediisocyanate were first stirred and reacted at room temperature for 5 h, and then stirred and reacted at 50 °C for 2 h to obtain the target product monomer. The rest is the same as in Example 1. In this embodiment, the structural formula of the multifunctional monomer is: .

[0081] Example 9 The main difference between Example 9 and Example 1 is: In the prepolymer solution, the multifunctional monomer is composed of the multifunctional monomer prepared in Example 1 (referred to as monomer 1) and the multifunctional monomer prepared in Example 8 (referred to as monomer 2), with 0.5 mol of monomer 1 and 0.5 mol of monomer 2 added. The rest is the same as in Example 1.

[0082] Example 10 The main difference between Example 10 and Example 1 is: A method for preparing a prepolymer liquid includes the following steps: 5g of the multifunctional monomer prepared in Example 1 and 0.05g of azobisisobutyronitrile were dissolved in 94.95g of electrolyte to obtain a prepolymer solution; wherein the electrolyte solution included: 37.95g of propyl propionate, 12g of methyl ethyl carbonate, 14g of ethylene carbonate, 11g of fluoroethylene carbonate, 1g of propane sulpholol, 1g of ethylene sulfate, 2g of 1,3,6-hexanetrionitrile, 12g of lithium hexafluorophosphate, 3g of lithium difluorosulfonylimide and 1g of lithium difluorophosphate; The rest is the same as in Example 1.

[0083] Example 11 The main difference between Example 11 and Example 1 is: A method for preparing a prepolymer liquid includes the following steps: 3g of the multifunctional monomer prepared in Example 1 and 0.03g of azobisisobutyronitrile were dissolved in 96.97g of electrolyte to obtain a prepolymer solution; wherein the electrolyte solution included: 31.97g of propyl propionate, 10g of ethyl propionate, 10g of propylene carbonate, 10g of ethylene carbonate, 15g of fluoroethylene carbonate, 0.5g of vinylene carbonate, 1g of ethylene sulfate, 2.5g of 1,3,6-hexanetrionitrile, 13g of lithium hexafluorophosphate, 2.5g of lithium difluorosulfonylimide and 0.5g of lithium dioxaborate.

[0084] The rest is the same as in Example 1.

[0085] Example 12 The main difference between Example 12 and Example 1 is: A method for preparing a prepolymer liquid includes the following steps: 1g of the multifunctional monomer prepared in Example 1 and 0.01g of azobisisobutyronitrile were dissolved in 98.99g of electrolyte to obtain a prepolymer solution; wherein the electrolyte solution included: 41.99g of propyl propionate, 12g of methyl ethyl carbonate, 14g of ethylene carbonate, 11g of fluoroethylene carbonate, 1g of propane sulpholol, 1g of ethylene sulfate, 2g of 1,3,6-hexanetrionitrile, 12g of lithium hexafluorophosphate, 3g of lithium difluorosulfonylimide and 1g of lithium difluorophosphate; The rest is the same as in Example 1.

[0086] Example 13 The main difference between Example 13 and Example 1 is: A method for preparing a prepolymer liquid includes the following steps: 0.8 g of the multifunctional monomer prepared in Example 1 and 0.008 g of azobisisobutyronitrile were dissolved in 99.192 g of electrolyte to obtain a prepolymer solution; wherein the electrolyte solution included: 42.192 g of propyl propionate, 12 g of methyl ethyl carbonate, 14 g of ethylene carbonate, 11 g of fluoroethylene carbonate, 1 g of propane sulpholol, 1 g of ethylene sulfate, 2 g of 1,3,6-hexanetrionitrile, 12 g of lithium hexafluorophosphate, 3 g of lithium difluorosulfonylimide and 1 g of lithium difluorophosphate; The rest is the same as in Example 1.

[0087] Example 14 The main difference between Example 14 and Example 1 is: A method for preparing a prepolymer liquid includes the following steps: 7.3g of the multifunctional monomer prepared in Example 1 and 0.073g of azobisisobutyronitrile were dissolved in 92.627g of electrolyte to obtain a prepolymer solution; wherein the electrolyte solution included: 35.627g of propyl propionate, 12g of methyl ethyl carbonate, 14g of ethylene carbonate, 11g of fluoroethylene carbonate, 1g of propane sulpholol, 1g of ethylene sulfate, 2g of 1,3,6-hexanetrionitrile, 12g of lithium hexafluorophosphate, 3g of lithium difluorosulfonylimide and 1g of lithium difluorophosphate; The rest is the same as in Example 1.

[0088] Example 15 The main difference between Example 15 and Example 1 is: Replace 1,3-propanediisocyanate with 1,15-pentadecanediisocyanate, otherwise the same as in Example 1; In this comparative example, the structural formula of the multifunctional monomer is: .

[0089] Comparative Example 1 The main difference between Comparative Example 1 and Example 1 is: Replace the multifunctional monomer with the compound shown in formula (5) below: Equation (5); The rest is the same as in Example 1.

[0090] Comparative Example 2 The main difference between Comparative Example 2 and Example 1 is: Step (1) is as follows: Add 1 mol pentaerythritol, 2 mol acrylic acid, 6 g p-toluenesulfonic acid, 0.2 g copper chloride and 38 g cyclohexane to the flask; The rest is the same as in Example 1; In this comparative example, the structural formula of the multifunctional monomer is: .

[0091] Comparative Example 3 The main difference between Comparative Example 3 and Example 1 is: Replace the multifunctional monomer with the compound shown in formula (6) below: Equation (6); The rest is the same as in Example 1.

[0092] Test method: (a) Infrared spectroscopy test: The multifunctional monomer sample prepared in Example 1 was placed on the crystal surface of the optical platform of the ATR (model is20) infrared spectrometer. The infrared ATR testing software was opened, and the test parameters were set to a resolution of 4 and a scan count of 32. After starting the instrument, the knob above the reflector was rotated to press the sample into full contact with the emission aperture below, and data acquisition began. After the test was completed, the infrared spectral information of the sample was obtained as follows: Figure 1 As shown.

[0093] in, Figure 1 Infrared spectral test results show that at 3343 cm⁻¹ -1 The absorption peak that appears is the stretching vibration peak of the nitrogen-hydrogen bond in the urethane group; at 1721 cm⁻¹ -1 The absorption peak that appears is the stretching vibration peak of the carbonyl group, which is a characteristic peak of the carbonyl group in acrylates; at 1668 cm⁻¹ -1 The absorption peak that appears is the stretching vibration peak of the carbon-oxygen double bond in the urethane group; 1264 cm⁻¹ -1 The absorption peak that appears is the stretching vibration peak of the carbon-oxygen single bond of the urethane group; 1172 cm⁻¹ -1 The absorption peaks that appear are due to the stretching vibrations of the ester group, and these infrared absorption peaks all prove the chemical structure of the multifunctional monomer.

[0094] (ii) Viscosity test: The viscosity of the prepolymer solutions prepared in Examples 1-15 and Comparative Examples 1-3 was tested using an NDJ-5S digital rotary viscometer. During testing, the prepolymer solution sample was poured into a flat-bottomed container with a diameter greater than 60 mm. The prepolymer solution temperature was maintained at 25°C, and the operating table was stable and vibration-free. The instrument protective bracket was screwed into the lower end of the instrument in reverse. The L0 rotor was then screwed counterclockwise into the universal joint. The lifting knob was rotated to slowly immerse the rotor in the prepolymer solution until the rotor's liquid level mark (the groove scale) was flush with the liquid surface. The instrument was then leveled again. The rotor selection key was pressed to select the rotation speed, and then the OK key was pressed. The rotor began to rotate. After the displayed value stabilized, the stop key was pressed to read the viscosity value. The test results are shown in Table 1 below.

[0095] (III) Electrochemical stability window test: A stainless steel sheet was placed in a CR2016-type battery casing, and the prepolymer samples prepared in Examples 1-15 and Comparative Examples 1-3 were dropped in. A lithium sheet and battery casing were then placed on top and clamped in place. The CR2016-type button cell assembly was completed in a glove box filled with high-purity argon gas. Four cells were prepared for each sample group. The samples were heated to 50°C and reacted for 24 hours. The electrochemical stability window was measured using a linear voltammetric scan with an electrochemical workstation (BioLogic Science Instruments). The initial potential was 2.5 V, the highest potential was 6 V, and the scan rate was 10 mV / s. The voltage value corresponding to the intersection of the tangent line of the current slope increase region and the horizontal axis in the curve was read as the high-voltage withstand window. The test results are shown in Table 1 below. Figure 2 As shown.

[0096] in, Figure 2 This is a scan curve of the electrochemical stability window of the solid electrolyte in Example 1 of this application. Figure 2 It can be seen that the solid electrolyte of Example 1 has a high electrochemical stability window of 4.71V, which can withstand high voltage and helps to improve the high voltage resistance of the battery.

[0097] (iv) Conductivity test: The electrode rings that fix the electrolyte container and the polytetrafluoroethylene (PTFE) single ring that serves as the electrolyte container are placed at the bottom of the battery casing. Then, the prepolymer samples prepared in Examples 1-15 and Comparative Examples 1-3 are dropped into the electrolyte container, ensuring the prepolymer completely fills the chamber. A stainless steel electrode plug is then placed on top, forming the blocking electrode. Finally, the battery casing is covered, and the wing nut is tightened to complete the battery assembly. The assembled blocking battery is directly connected to an electrochemical workstation (VMP-3e, Bio-Logic) and placed in a 50°C constant temperature oven for high-temperature curing. AC impedance testing is performed at frequencies from 1MHz to 0.03Hz, and EIS testing is also conducted. σ is the ionic conductivity, L is the electrolyte thickness, S is the contact area between the electrolyte membrane and the electrode, and R is the impedance measured by an impedance meter. The ionic conductivity (σ, mS / cm) of the solid electrolyte is calculated using the above formula. The test results are shown in Table 1 below.

[0098] (v) High-voltage cycling test: Positive electrode preparation: Lithium cobalt oxide material (95%-99% by mass) and acetylene black conductive agent (1%-5% by mass) are ground and mixed. Polyvinylidene fluoride (1%-5% by mass) is added and dispersed in 1-methyl-2-pyrrolidone (NMP). The mixture is then mixed to obtain a positive electrode slurry. NMP is used for mixing, dispersing and adjusting the viscosity of the slurry. It volatilizes during drying and is not included in the mass percentage of the positive electrode material. The positive electrode material is coated on the surface of aluminum foil and dried to obtain the positive electrode sheet.

[0099] Preparation of negative electrode sheet: Silicon particles and graphite are mixed evenly at a mass ratio of 9:1 to obtain silicon-carbon composite negative electrode material. Then, 80%-95% of the silicon-carbon composite negative electrode material is added to 1%-10% of conductive carbon black and ground and mixed. Then, 1%-5% of sodium carboxymethyl cellulose, 1%-5% of polystyrene-butadiene copolymer and water are added and ground, dispersed and mixed. The mixture is then coated on the surface of copper foil and dried to obtain the negative electrode sheet.

[0100] The diaphragm is a porous support material that isolates the positive and negative electrodes, and a polyethylene diaphragm is used.

[0101] The prepolymer samples prepared in Examples 1-15 and Comparative Examples 1-3 were injected into the battery system consisting of a positive electrode, a separator, and a negative electrode. The samples were pre-sealed and allowed to stand at room temperature for 24-72 hours. Then, they were heated at 40℃-80℃ for 12-72 hours to cure the solid-state battery.

[0102] High-voltage cycle testing of solid-state pouch cell full batteries: First, the battery was formed by charging with a constant current of 0.02C for 60 minutes, 0.05C for 60 minutes, 0.1C for 120 minutes, and 0.2C for 180 minutes. It was then heated at 45℃ for 24 hours, cooled to room temperature, and charged with a constant current and voltage of 0.01C until the upper limit voltage of 4.58V was reached. The cutoff current was 0.02C, and the battery was allowed to rest for 10 minutes. Then, it was discharged with a constant current of 0.1C to 3V and allowed to rest for 10 minutes. This process was repeated 4 times at room temperature using the CC-CV method. Next, the battery was charged and discharged at room temperature with a constant current and voltage of 1C, with a charge / discharge cutoff voltage of 3V-4.58V, for 500 cycles. The capacity retention rate (%) after 500 high-voltage cycles was obtained. The test results are referenced below. Figure 3 See Table 1.

[0103] in, Figure 3 These are high-voltage cycling curves of solid-state pouch cells from Embodiment 1 and Comparative Example 1 of this application, wherein... Figure 3 The red curve in the figure is the high-voltage cycling curve of the solid-state pouch cell of Example 1. Figure 3 The black curve in the figure is the high-voltage cycling curve of the solid-state pouch cell in Comparative Example 1. Figure 3It can be seen that after 500 high-voltage cycles, the solid-state battery corresponding to Example 1 has a capacity that decreases to 94.6% of its original value, while the solid-state battery of Comparative Example 1 has a capacity that decreases to 85.0% of its original value. This shows that the solid electrolyte of Example 1 can still maintain the normal operation of the battery during the full-cell high-voltage charge-discharge cycle. The solid electrolyte of Example 1 can withstand higher voltages and has higher voltage stability, thereby improving the battery cycle life.

[0104] Table 1

[0105] As shown in Table 1, the batteries containing the solid electrolytes of Examples 1 to 15 exhibit high capacity retention and electrochemical stability window after 500 high-voltage cycles. This demonstrates that using the multifunctional monomers from the embodiments of this application as raw materials to prepare solid electrolytes can improve the high-voltage performance of solid electrolytes.

[0106] A comparison of Examples 1-12, 13, and 14 shows that controlling the mass percentage of the multifunctional monomer in the prepolymer solution within the range of 1%-5% can further ensure that the battery has good high-voltage resistance.

[0107] A comparison of Examples 1-3, 4, 5 and 8 shows that when R7 in a multifunctional monomer is an alkyl group and the multifunctional monomer has a symmetrical molecular structure, it can further ensure that the battery has better high-voltage performance and a wider electrochemical stability window.

[0108] A comparison of Examples 1-7 and Example 15 shows that R7 has a structure as shown in Formula (2) or Formula (3), and the sum of n1 and n2 is between 1 and 10, and / or the sum of n4 and n5 is between 1 and 10, which can further ensure that the battery has better high voltage resistance, a wider electrochemical stability window and higher conductivity.

[0109] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A solid state electrolyte, characterized by, The solid-state electrolyte is formed by curing a multifunctional monomer in an electrolyte solution; The multifunctional monomer has a structure as shown in formula (1): Formula (1).

2. The solid-state electrolyte of claim 1, wherein, The solid-state electrolyte has an electrical conductivity of 4 mS / cm-10 mS / cm.

3. The solid-state electrolyte of claim 1, wherein, The multifunctional monomer is obtained by reacting 1,4-dimethylene cyclohexane diisocyanate and a trifunctional acrylate compound.

4. The solid-state electrolyte of claim 1, wherein, The electrolyte solution includes a solvent, a lithium salt, and / or an additive; The mass percentage of the solvent in the electrolyte solution is 79%-89%; The mass percentage of the lithium salt in the electrolyte solution is 10%-20%; The mass percentage of the additive in the electrolyte solution is 1%-5%.

5. A method of producing a solid-state electrolyte as claimed in any one of claims 1 to 4, characterized in that, The preparation method includes: providing a prepolymer solution including an electrolyte solution and a multifunctional monomer; causing in-situ curing reaction of the multifunctional monomer in the prepolymer solution to obtain the solid-state electrolyte; The multifunctional monomer is a multifunctional monomer having a structure as shown in formula (1).

6. The preparation method of the solid-state electrolyte according to claim 5, wherein The curing temperature of the curing reaction is 40-80°C, and / or the curing time is 12-72 hours; and / or The viscosity of the prepolymer solution at room temperature is 2-8 mPa.s; and / or The prepolymer solution further includes an initiator.

7. The preparation method of the solid-state electrolyte according to claim 5, wherein The mass percentage of the multifunctional monomer in the prepolymer solution is 1%-5%; and / or The mass percentage of the electrolyte solution in the prepolymer solution is 94%-98.997%; and / or The electrolyte solution includes a solvent, a lithium salt, and / or an additive; and / or The mass percentage of the initiator in the prepolymer solution is 0.003%-0.15%; and / or The initiator includes at least one of an azo initiator and a peroxide initiator.

8. The preparation method of the solid-state electrolyte according to claim 7, wherein The solvent includes at least one of a carbonate solvent and a carboxylate solvent; and / or The mass percentage of the solvent in the electrolyte solution is 79%-89%; and / or The lithium salt includes at least one of lithium hexafluorophosphate, lithium perchlorate, lithium difluoro(oxalato)borate, lithium trifluoromethanesulfonimide, lithium bis(fluorosulfonyl)imide, lithium bis(oxalato)borate, lithium tetrafluoroborate, and lithium difluorophosphate; and / or The mass percentage of the lithium salt in the electrolyte solution is 10%-20%; and / or The additive includes at least one of propane sultone, ethylene sulfate, and 1,3,6-hexanetricarbonitrile; and / or The mass percentage of the additive in the electrolyte solution is 1%-5%.

9. A lithium-ion battery, characterized by The solid-state electrolyte includes the solid-state electrolyte according to any one of claims 1-4, or is prepared by the preparation method of the solid-state electrolyte according to any one of claims 5-8.

10. An electrical device, comprising: The solid-state electrolyte includes the solid-state electrolyte according to any one of claims 1-4, or is prepared by the preparation method of the solid-state electrolyte according to any one of claims 5-8, or includes the lithium ion battery according to claim 9.

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