A polymer monomer, a solid electrolyte and its preparation method, a lithium-ion battery and an electrical device.

Abstract

This application provides a polymeric monomer, a solid electrolyte, a method for preparing the same, a lithium-ion battery, and an electrical device, relating to the field of lithium-ion battery technology. The polymeric monomer has the following structural formula: where R0 is selected from saturated alkyl, unsaturated alkyl, aromatic, or groups containing non-carbon atoms; R1, R2, R3, R4, R5, and R6 each independently include an acrylic acid group or a hydroxyl group. The polymeric monomer efficiently crosslinks into a three-dimensional network, improving the thermal safety performance of the battery and reducing side reactions between the electrode and the electrolyte.

Description

Technical Field

[0001] This application relates to the field of lithium-ion battery technology, and in particular to a polymer monomer, a solid electrolyte and its preparation method, a lithium-ion battery and an electrical device. Background Technology

[0002] Thermal runaway of lithium batteries is the main cause of lithium battery fire and explosion safety accidents. Once a single battery experiences thermal runaway, it can easily lead to a domino effect, ultimately causing fires or even explosions in electric vehicles and energy storage power stations. Therefore, the prevention and control of thermal runaway of lithium batteries is the key to ensuring the safe use of batteries.

[0003] Existing electrolyte materials cannot meet the high thermal safety requirements of lithium-ion batteries, especially solid-state batteries. Specifically, the interfacial contact between the solid electrolyte and electrode materials is unstable. The contact changes from a liquid-solid contact in the electrolyte system to a solid-solid contact, making the solid electrolyte material highly susceptible to localized cracking. This leads to interface deterioration, damage to the interfacial structure, and compromises the battery's thermal safety stability. When the interfacial film decomposes, an exothermic reaction occurs between the electrolyte and the negative electrode active material, and the lithium salt also undergoes a violent exothermic reaction with the electrolyte. The heat and gases generated by these reactions further accelerate the battery's thermal runaway process.

[0004] Therefore, in order to meet the requirements of high thermal safety, the structure of solid electrolyte materials needs to be further optimized and improved. Summary of the Invention

[0005] The purpose of this application is to provide a polymer monomer, a solid electrolyte and a method for preparing the same, a lithium-ion battery and an electrical device to solve the above-mentioned problems.

[0006] To achieve the above objectives, the first aspect of this application provides a polymeric monomer with the following structural formula:

[0007]

[0008] Wherein, R0 is selected from saturated alkyl, unsaturated alkyl, aromatic or groups containing non-carbon atoms;

[0009] R1, R2, R3, R4, R5, and R6 are each independently selected from acrylic acid groups or hydroxyl groups.

[0010] Optionally, the polymeric monomer satisfies at least one of the following conditions:

[0011] A. The saturated alkyl group includes Where n1 is any positive integer from 1 to 10;

[0012] B. The unsaturated alkyl group includes and / or

[0013] C. The aromatic group includes and / or

[0014] D. The non-carbon atom-containing group is selected from

[0015] Among them, n2, n3, n4, n5, and n6 are each independent positive integers from 1 to 10;

[0016] E. The total number of R1-R6 is 4-6.

[0017] A second aspect of this application provides a method for preparing the aforementioned polymeric monomer, comprising:

[0018] 3,3-dihydroxymethyl-1,3-propanediol, acrylic acid, and catalyst were mixed in the first reaction to obtain an acrylic polyol ester precursor.

[0019] The acrylic polyol ester precursor and the disulfonic acid compound are mixed in a second process, and a second reaction is carried out to obtain the polymer monomer.

[0020] Optionally, the method for preparing the polymeric monomer satisfies at least one of the following conditions:

[0021] A. The molar ratio of the 3,3-bis(hydroxymethyl)-1,3-propanediol to the acrylic acid is 1:2-4;

[0022] B. The mass of the catalyst is 0.2%-2% of the total mass of the 3,3-dihydroxymethyl-1,3-propanediol and the acrylic acid;

[0023] C. The molar ratio of the acrylic polyol ester precursor to the disulfonic acid compound is 1.8-2.2:1;

[0024] D. The temperature of the first reaction is 50℃-90℃, and the time is 2h-12h;

[0025] E. The temperature of the second reaction is 50℃-90℃, and the time is 2h-12h;

[0026] F. The catalyst comprises dibutyl dilaurate;

[0027] G. The disulfonic acid compound includes one or more of 1,3-propanedisulfonic acid, 1,4-butanedisulfonic acid, 1,4-piperazine diethanesulfonic acid, 1,4-piperazine dipropanesulfonic acid, 1,4-benzenedisulfonic acid, or 2,6-naphthalenedisulfonic acid.

[0028] A third aspect of this application provides a solid electrolyte, the raw materials of which, by mass parts, include:

[0029] Electrolyte 95-99 parts, polymer monomer 1-5 parts, initiator 0.003-0.15 parts;

[0030] The polymeric monomer includes the polymeric monomers described above or is prepared by the method described above;

[0031] The electrolyte is made from lithium salt and organic solvent.

[0032] Optionally, the solid electrolyte satisfies at least one of the following conditions:

[0033] A. The electrolyte lithium salt includes one or more of methyl ethyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, propane sulpholactone, and vinyl sulfate;

[0034] B. The electrolyte lithium salt includes one or more of lithium hexafluorophosphate, lithium difluorosulfonylimide, lithium difluorophosphate, and lithium difluorooxalate borate;

[0035] C. The raw materials for the electrolyte, based on a total mass of 100%, include:

[0036] Electrolyte lithium salt 10%-20%, organic solvent 80%-90%;

[0037] D. The initiator includes azo compounds;

[0038] E. The viscosity of the solid electrolyte is 2 mPas-7 mPas.

[0039] A fourth aspect of this application provides a method for preparing the aforementioned solid electrolyte, comprising:

[0040] The raw materials for the solid electrolyte are mixed in a third step to prepare the solid electrolyte.

[0041] Optionally, the method for preparing the solid electrolyte satisfies at least one of the following conditions:

[0042] A. The relative humidity of the third mixture is less than or equal to 2%;

[0043] B. The dew point temperature of the third mixture is less than or equal to -40°C.

[0044] The fifth aspect of this application provides a lithium-ion battery, comprising the solid electrolyte or prepared by the method for preparing the solid electrolyte.

[0045] The sixth aspect of this application provides an electrical device including the aforementioned lithium-ion battery.

[0046] Compared with the prior art, the beneficial effects of this application include:

[0047] The polymer monomer provided in this application, firstly, contains a sulfonate structure. This sulfonate structure has a low reduction potential, enabling it to preferentially reduce and decompose on the electrode surface during the initial stages of battery charge-discharge cycles, thus contributing to the formation of the SEI film. This preferential reduction characteristic makes the sulfonate groups play a key role in the SEI film formation process. Secondly, the two sulfonate groups can be converted into an organic solid electrolyte even with a small amount of polymer monomer added. The polymer monomer efficiently crosslinks into a three-dimensional network, resulting in a lower electrolyte viscosity. This reduces the interfacial wetting problem caused by viscosity increases, improves the effective interfacial contact between the electrolyte material and the electrode, and enhances... The interface stability of solid-state batteries improves their thermal safety performance. Furthermore, the introduction of sulfonate groups can significantly improve the quality of the SEI interface film. Sulfonate groups can undergo electrochemical reactions with the active materials on the electrode surface (mainly the negative electrode active materials) to generate stable compounds. These compounds can firmly adhere to the electrode surface, forming a dense and stable SEI interface film. In the early stages of heat accumulation, this film can suppress the degree of SEI interface film decomposition and the heat released. This SEI film can effectively prevent further erosion of the electrode by solvent molecules and electrolyte salts, and can also reduce side reactions between the electrode and the electrolyte, thereby improving the battery's safety performance.

[0048] The method for preparing the polymer monomer provided in this application is simple to operate.

[0049] The solid electrolyte provided in this application has high ion conductivity and ion transport performance.

[0050] The method for preparing solid electrolytes provided in this application is simple to operate.

[0051] The lithium-ion battery and electrical device provided in this application exhibit good rate performance during high-rate charge and discharge, and the electrochemical properties are significantly improved. Attached Figure Description

[0052] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0053] Figure 1 The infrared spectrum of the polymer monomer prepared in Example 1 is shown below.

[0054] Figure 2 This is a comparison chart of the rate performance of the solid-state batteries prepared in Example 1 and Comparative Example 1.

[0055] Figure 3The image shows a comparison of the thermal test results of the solid-state batteries prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0056] As used in this article:

[0057] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0058] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0059] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0060] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0061] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0062] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0063] The first aspect of this application provides a polymeric monomer with the following structural formula:

[0064]

[0065] It should be noted that the SEI film induced by sulfonate compounds is not only stable, thin and dense, but also has a greater advantage for the high-rate performance and other electrochemical properties of the battery.

[0066] It is also important to note that sulfonate groups can undergo electrochemical reactions with the active materials on the electrode surface (mainly the negative electrode active materials) to form a stable solid electrolyte interphase (SEI) film. This is a complex and crucial process. Sulfonate groups enhance the quality of the interphase film; the introduction of sulfonate groups can significantly improve the quality of the SEI interphase film. These groups can react electrochemically with the active materials on the electrode surface to generate stable compounds. These compounds can firmly adhere to the electrode surface, forming a dense and stable SEI interphase film. Once the SEI film is stably formed, it can effectively prevent side reactions within the battery, protect the electrode materials from damage, and suppress the degree of SEI interphase film decomposition and the heat released during the early stages of heat accumulation. This SEI film can effectively prevent further erosion of the electrode by solvent molecules and electrolyte salts, and also reduce side reactions between the electrode and the electrolyte, improving the battery's safety performance.

[0067] R0 is selected from saturated alkyl, unsaturated alkyl, aromatic, or groups containing non-carbon atoms. These groups are ideal linking groups, possessing a certain degree of chemical stability, and can stably link them together without deteriorating the chemical properties of the terminal groups. Furthermore, various organic compounds can be formed through different structural linking methods, enriching the structure and properties of monomers and further diversifying their structures, thus enhancing the chemical properties of molecules.

[0068] It is important to note that R0 connects the large end groups at both ends. The linking group R0 imparts strong preparability to the polymer monomer, enabling its synthesis through various methods. Furthermore, the linking group R0 possesses strong chemical bond energy, effectively connecting the large end groups at both ends and improving the strength and elasticity of the polymer gel. In addition, the introduction of R0 chemical bonds primarily enhances the overall stability of the monomer and polymer structure. Compared to systems connected solely through physical interactions (such as van der Waals forces, hydrogen bonds, etc.) or other means, R0 chemical bonds typically have higher bond energy and chemical bond strength, making the monomer and polymer structures of the material more difficult to disrupt.

[0069] In some embodiments, R0 is selected from saturated alkyl groups and unsaturated alkyl groups.

[0070] R1, R2, R3, R4, R5, and R6 are each independently selected from acrylic acid groups or hydroxyl groups. The large terminal groups R1-R6 on both sides are connected to the main structure via R0 chemical bonds, forming a more compact and stable structure and reducing the impact of external factors (such as high temperature and external mechanical impact) on the structure. The large terminal groups connected by R0 chemical bonds have a more symmetrical structure, which can improve the thermal stability of the material's chemical structure. These large terminal groups can absorb and disperse heat when heated, thereby slowing down the thermal decomposition and degradation process of the material. Moreover, the presence of large terminal groups can also reduce the deformation and flow of the material at high temperatures, improving its thermal stability. This is of great significance for improving the thermal safety of battery cells when applying organic solid electrolytes.

[0071] When R1, R2, R3, R4, R5, and R6 are acrylic groups, they become functional groups of the polymer monomer. If they are hydroxyl groups, they are unreacted groups, remaining as the original hydroxyl groups and unable to provide functionality.

[0072] It is important to note that the acrylic group is the functional group of the monomer provided in this application. 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. Functionality determines the number of active sites in the monomer molecule during the reaction, thus affecting the reaction rate and reaction pathway. Generally speaking, the higher the functionality, the more active sites the monomer molecule has in the reaction, the faster the reaction rate, and the greater the probability that the monomer molecule will participate in the polymerization reaction and chain growth. High-functionality monomers are more likely to form highly cross-linked polymer network structures. Each functionality is a reaction site, and the dense reaction sites endow the monomer with high reactivity, enabling polymerization reactions to occur at low contents and concentrations to form polymer networks. This allows the proportion of the polymeric monomer in the solid electrolyte to be compressed to an extremely low level.

[0073] It should also be noted that during the heating process, the acrylic groups undergo addition polymerization, that is, during the in-situ curing process, they cross-link to form a polymer gel, which acts as a skeletal support for the solid electrolyte and effectively absorbs lithium salts and solvents.

[0074] In some embodiments, the polymeric monomer satisfies at least one of the following conditions:

[0075] A. The saturated alkyl group includes Where n1 is any positive integer from 1 to 10;

[0076] Optionally, n1 can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or any positive integer between 1 and 10;

[0077] B. The unsaturated alkyl group includes and / or

[0078] C. The aromatic group includes and / or

[0079] D. The non-carbon atom-containing group is selected from

[0080] Among them, n2, n3, n4, n5, and n6 are each independent positive integers from 1 to 10;

[0081] Optionally, n2, n3, n4, n5, and n6 can each be independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or any positive integer between 1 and 10;

[0082] E. The total number of R1-R6 is 4-6.

[0083] Optionally, the total number of acrylic groups in R1, R2, R3, R4, R5, and R6 can be 4, 5, 6, or any positive integer between 4 and 6;

[0084] This can be understood as the total number of acrylic groups in R1, R2, R3, R4, R5, and R6 being 4-6.

[0085] It is important to note that the higher the number of acrylic groups in R1-R6, the higher the functionality, and the more readily polymerization can occur at lower contents and concentrations to form a polymer network.

[0086] A second aspect of this application provides a method for preparing the aforementioned polymeric monomer, comprising:

[0087] 3,3-dihydroxymethyl-1,3-propanediol, acrylic acid, and catalyst were mixed in the first reaction to obtain an acrylic polyol ester precursor.

[0088] The acrylic polyol ester precursor and the disulfonic acid compound are mixed in a second process, and a second reaction is carried out to obtain the polymer monomer.

[0089] In some embodiments, the method for preparing the polymeric monomer satisfies at least one of the following conditions:

[0090] A. The molar ratio of the 3,3-bis(hydroxymethyl)-1,3-propanediol to the acrylic acid is 1:2-4;

[0091] Optionally, the molar ratio of 3,3-dihydroxymethyl-1,3-propanediol to acrylic acid can be any value between 1:2, 1:3, 1:4 or 1:2-4;

[0092] B. The mass of the catalyst is 0.2%-2% of the total mass of the 3,3-dihydroxymethyl-1,3-propanediol and the acrylic acid;

[0093] Optionally, the mass of the catalyst can be any value between 0.2%, 0.5%, 1%, 1.5%, 2%, or 0.2%-2% of the total mass of 3,3-dihydroxymethyl-1,3-propanediol and acrylic acid.

[0094] C. The molar ratio of the acrylic polyol ester precursor to the disulfonic acid compound is 1.8-2.2:1;

[0095] Optionally, the molar ratio of the acrylic polyol ester precursor to the disulfonic acid compound can be any value between 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, or 1.8:2.2:1.

[0096] D. The temperature of the first reaction is 50℃-90℃, and the time is 2h-12h;

[0097] Optionally, the temperature of the first reaction can be any value between 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃ or 50℃-90℃, and the time can be any value between 2h, 4h, 6h, 8h, 10h, 12h or 2h-12h.

[0098] E. The temperature of the second reaction is 50℃-90℃, and the time is 2h-12h;

[0099] Optionally, the temperature of the second reaction can be any value between 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃ or 50℃-90℃, and the time can be any value between 2h, 4h, 6h, 8h, 10h, 12h or 2h-12h.

[0100] F. The catalyst comprises dibutyl dilaurate;

[0101] G. The disulfonic acid compound includes one or more of 1,3-propanedisulfonic acid, 1,4-butanedisulfonic acid, 1,4-piperazine diethanesulfonic acid, 1,4-piperazine dipropanesulfonic acid, 1,4-benzenedisulfonic acid, or 2,6-naphthalenedisulfonic acid.

[0102] A third aspect of this application provides a solid electrolyte, the raw materials of which, by mass parts, include:

[0103] Electrolyte 95-99 parts, polymer monomer 1-5 parts, initiator 0.003-0.15 parts;

[0104] Optionally, the raw materials of the solid electrolyte, by mass parts, can be any value between 95, 96, 97, 98, 99 parts or 95-99 parts for the electrolyte, any value between 1, 2, 3, 4, 5 parts or 1-5 parts for the polymerizable monomer, and any value between 0.003, 0.005, 0.01, 0.1, 0.15 parts or 0.003-0.15 parts for the initiator;

[0105] It should be noted that, given that polymerized monomers form bulk molecules after polymerization, the movement of bulk molecules is more difficult than that of small molecules in electrolyte solvents and lithium salt cations and anions. Under these conditions, lithium-ion batteries are inevitably limited. However, the amount of polymerized monomers added in this application is relatively low, which can reduce their hindrance to the high-speed conduction of lithium ions and maintain a high level of overall ionic conductivity of the electrolyte.

[0106] The polymeric monomer includes the polymeric monomers described above or is prepared by the method described above;

[0107] It is important to note that the solid electrolyte formed by introducing polymeric monomers into the solid electrolyte is essentially an organic solid electrolyte prepolymer. After heating and curing, the prepolymer forms an organic solid electrolyte in a gel-like state. Before heating and curing, the low viscosity of the prepolymer is beneficial for its wetting of the electrodes inside the battery and for the interfacial electrochemical reactions of the active particles in the electrodes, thus improving the interfacial stability of the solid battery and being crucial for the battery's thermal safety performance.

[0108] The electrolyte is made from lithium salt and organic solvent.

[0109] In some embodiments, the solid electrolyte satisfies at least one of the following conditions:

[0110] A. The electrolyte lithium salt includes one or more of methyl ethyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, propane sulpholactone, and vinyl sulfate;

[0111] B. The electrolyte lithium salt includes one or more of lithium hexafluorophosphate, lithium difluorosulfonylimide, lithium difluorophosphate, and lithium difluorooxalate borate;

[0112] C. The raw materials for the electrolyte, based on a total mass of 100%, include:

[0113] Electrolyte lithium salt 10%-20%, organic solvent 80%-90%;

[0114] Optionally, the raw materials of the electrolyte, based on a total mass of 100%, may include lithium salt electrolyte, which may be any value between 10%, 15%, 20%, or 10%-20%, and organic solvent, which may be any value between 80%, 85%, 90%, or 80%-90%.

[0115] D. The initiator includes azo compounds;

[0116] In some embodiments, the azo compounds include one or more of azobisisobutyronitrile, azobisisoheptanenitrile, and dimethyl azobisisobutyrate;

[0117] E. The viscosity of the solid electrolyte is 2 mPas-7 mPas.

[0118] Optionally, the viscosity of the solid electrolyte before heating and curing can be any value between 2 mPas, 3 mPas, 4 mPas, 5 mPas, 6 mPas, 7 mPas, or 2 mPas-7 mPas.

[0119] A fourth aspect of this application provides a method for preparing the aforementioned solid electrolyte, comprising:

[0120] The raw materials for the solid electrolyte are mixed in a third step to prepare the solid electrolyte.

[0121] In some embodiments, the electrolyte prepolymer solution is mixed and injected into the battery system of positive electrode, separator and negative electrode, pre-sealed and left to stand at room temperature for 24h-72h, and then heated and cured at 40℃-80℃ for 12h-72h. During heating, the prepolymer solution reacts inside the dry cell and organic solid electrolyte is obtained by in-situ thermal curing.

[0122] In some embodiments, the method for preparing the solid electrolyte satisfies at least one of the following conditions:

[0123] A. The relative humidity of the third mixture is less than or equal to 2%;

[0124] Optionally, the relative humidity of the third mixture can be 0.01%, 0.1%, 1%, 2%, or any value less than or equal to 2%.

[0125] B. The dew point temperature of the third mixture is less than or equal to -40°C.

[0126] Optionally, the dew point temperature of the third mixture can be any value of -100℃, -80℃, -60℃, -40℃ or less than or equal to -40℃.

[0127] It's important to note that dew point temperature refers to the temperature at which air reaches saturation under constant water vapor content and pressure, and is expressed in degrees Celsius (°C) or degrees Fahrenheit (℉). Essentially, it's the temperature at which water vapor and water reach equilibrium.

[0128] The fifth aspect of this application provides a lithium-ion battery, comprising the solid electrolyte or prepared by the method for preparing the solid electrolyte.

[0129] In some embodiments, the lithium-ion battery further includes a positive electrode and a negative electrode;

[0130] The raw materials for the positive electrode sheet, based on 100% of their total mass, include:

[0131] The positive electrode active material comprises 80%-95%, conductive agent 1%-10%, binder 1%-10%, and the balance is organic solvent.

[0132] Among them, the positive electrode active material includes one or more of lithium iron phosphate, lithium cobalt oxide and nickel cobalt manganese ternary positive electrode, preferably high nickel ternary positive electrode NCM811;

[0133] Conductive agents include acetylene black;

[0134] The binder includes polyvinylidene fluoride (PVDF);

[0135] Organic solvents include 1-methyl-2-pyrrolidone (NMP).

[0136] The raw materials for the negative electrode sheet, based on 100% of their total mass, include:

[0137] The composition is as follows: 80%-95% negative electrode active material, 1%-10% conductive agent, 1%-5% binder, 1%-5% additives, and the balance is solvent.

[0138] Negative electrode active materials include silicon-carbon composite materials;

[0139] Conductive agents include carbon black (SP);

[0140] The binder includes sodium carboxymethyl cellulose (CMC);

[0141] Additives include polystyrene-butadiene copolymer (SBR);

[0142] Solvents include water.

[0143] The sixth aspect of this application provides an electrical device including the aforementioned lithium-ion battery.

[0144] In some embodiments, electrical equipment includes, but is not limited to, one or more of electric vehicles, electric bicycles, smart home devices, robots, heavy trucks, ships, and energy storage systems.

[0145] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0146] Example 1

[0147] The first aspect of this embodiment provides a polymeric monomer with the following structural formula:

[0148]

[0149] In the equivalent structural formula, n1 is 3, and R1-R6 are all acrylic acid groups.

[0150] The second aspect of this embodiment provides a method for preparing the above-mentioned polymeric monomer, comprising:

[0151] 2 mol of 2,2-dihydroxymethyl-1,3-propanediol and 6 mol of acrylic acid were stirred evenly. Then, 0.5 wt% of dibutyltin dilaurate was added as a catalyst to the above 2,2-dihydroxymethyl-1,3-propanediol and acrylic acid. The mixture was stirred at 60 °C for 6 h to obtain the precursor.

[0152] The above precursor was then stirred with 1 mol of 1,3-propanedisulfonic acid and reacted at 60°C for 4 h. Finally, it was cooled to room temperature, filtered through an alumina column, washed three times with deionized water, and distilled under reduced pressure to obtain the target product polymer monomer.

[0153] Infrared spectroscopy test of the polymer monomer as follows Figure 1 As shown, at 1346cm -1 An absorption peak appears, which is the stretching vibration peak of the sulfonate group, at 1721 cm⁻¹. -1 An absorption peak appears, which is the stretching vibration peak of the carbonyl group. This is a characteristic peak of the carbonyl group in acrylates, at 1164 cm⁻¹. -1 These infrared absorption peaks, representing the CO stretching vibration peaks in acrylates, all confirm the chemical structure of the polymer monomers.

[0154] The third aspect of this embodiment provides a solid electrolyte, the raw materials of which, by mass parts, include:

[0155] 97g electrolyte, 3g polymer monomer 1, 0.03g initiator azobisisobutyronitrile;

[0156] The electrolyte includes 35g methyl ethyl carbonate, 19g ethylene carbonate, 15g propylene carbonate, 10g fluoroethylene carbonate, 1g propane sulphol, 2g ethylene sulfate, 10g lithium hexafluorophosphate, 4g lithium difluorosulfonyl imide, 0.5g lithium difluorophosphate, and 0.5g lithium difluorooxalate borate.

[0157] The fourth aspect of this embodiment provides a method for preparing a solid electrolyte, comprising:

[0158] Mix the above raw materials evenly at room temperature, relative humidity below 2%, and dew point below -40°C.

[0159] The fifth aspect of this embodiment provides a sodium-ion battery and a method for preparing the same, including:

[0160] Positive electrode preparation method: 95% by mass of high-nickel ternary positive electrode material NCM811 and 2% by mass of conductive agent acetylene black are ground and mixed. 3% by mass of polyvinylidene fluoride (PVDF) is added and dispersed in solvent 1-methyl-2-pyrrolidone (NMP). The mixture is then ground and mixed to obtain the positive electrode material. NMP is used for mixing, dispersing, and adjusting the slurry viscosity. It volatilizes during drying and is therefore not included in the mass percentage of the positive electrode material. The positive electrode material is coated onto the surface of aluminum foil and dried to obtain the positive electrode.

[0161] Negative electrode preparation method: 95% by weight of silicon-carbon composite negative electrode material is added to 1.5% by weight of conductive carbon black (SP) and ground and mixed. 1.5% by weight of sodium carboxymethyl cellulose (CMC) and 2% by weight of polystyrene-butadiene copolymer (SBR) are added and dispersed in water. The mixture is then ground, dispersed, and coated onto a copper foil surface, and dried to obtain the negative electrode. The separator is a porous support material that isolates the positive and negative electrodes; polyethylene separators, polypropylene separators, and polytetrafluoroethylene nonwoven fabrics, etc., can be used.

[0162] The solid electrolyte was injected into the dry cell assembled with positive and negative electrodes and separator, pre-sealed with a heat sealer, left to stand at room temperature for 24 hours, and then placed in a hot oven and slowly heated to 50°C for 12 hours. During the heating, the solid electrolyte reacted inside the dry cell and organic solid electrolyte was obtained through in-situ thermal curing to form a solid battery. The solid battery was then charged and discharged to test its performance.

[0163] Example 2

[0164] The difference from Example 1 is that n1 is 7, and the structural formula is:

[0165]

[0166] Example 3

[0167] The difference from Example 1 is that R0 is The structural formula is:

[0168]

[0169] Example 4

[0170] The difference from Example 1 is that R0 is The structural formula is:

[0171]

[0172] Example 5

[0173] The difference from Example 1 is that R0 is an unsaturated alkyl group, with the following specific structural formula:

[0174]

[0175] Example 6

[0176] The difference from Example 1 is that R0 contains a non-carbon atom group, and its structural formula is:

[0177]

[0178] Example 7

[0179] The difference from Example 6 is that n2 is 1, and the structural formula is:

[0180]

[0181] Example 8

[0182] The difference from Example 1 is that R0 contains a non-carbon atom group, and its structural formula is:

[0183]

[0184] Example 9

[0185] The difference from Example 1 is that R0 contains a non-carbon atom group, and its structural formula is:

[0186]

[0187] Example 10

[0188] The difference from Example 1 is that R0 contains a non-carbon atom group, and its structural formula is:

[0189]

[0190] Example 11

[0191] The difference from Example 1 is that the number of acrylic groups is 4, and the structural formula is:

[0192]

[0193] Example 12

[0194] The difference from Example 1 is that the amount of polymerized monomer used is 5g.

[0195] Example 13

[0196] The difference from Example 1 is that the specific components of the electrolyte are 32g dimethyl carbonate, 6g ethyl methyl carbonate, 20g ethylene carbonate, 15g propylene carbonate, 10g fluoroethylene carbonate, 0.2g vinylene carbonate, 0.5g adiponitrile, 12.5g lithium hexafluorophosphate, and 0.8g lithium bis(oxalato)borate.

[0197] Example 14

[0198] The difference from Example 1 is that the initiator is dimethyl azobisisobutyrate.

[0199] Example 15

[0200] The difference from Example 1 is that: a solid electrolyte is injected into the battery system, pre-sealed and left to stand at room temperature for 72 hours, and then heated at 65°C for 24 hours to cure, thus obtaining a solid battery.

[0201] Comparative Example 1

[0202] The difference from Example 1 is that the polymer monomer does not have sulfate groups, and its structural formula is:

[0203]

[0204] The results of rate performance tests (3C / 0.2C discharge capacity retention) of the solid-state batteries prepared in Comparative Example 1 and Example 1 are as follows: Figure 2 As shown, the 3C high-rate discharge of Example 1 has a higher capacity retention rate. The solid electrolyte prepared in Example 1 makes the interface of the active particles stable and dense, and the ion transport is more efficient, thus improving the rate performance of the full battery.

[0205] The results of the full-cell hot box test of the solid-state batteries prepared in Comparative Example 1 and Example 1 are as follows: Figure 3 As shown, the battery in Comparative Example 1 experienced thermal runaway in a 150°C hot box, with the temperature rising sharply. The solid-state battery corresponding to Example 1, after being continuously heated in a hot box at 150°C, maintained a stable temperature and did not experience thermal runaway. This indicates that Example 1 can maintain normal operation of the battery even when the entire battery is continuously heated in a high-temperature hot box. The solid electrolyte in Example 1 can improve the thermal stability of the material, greatly stabilize the internal electrochemical structure of the battery, and improve the thermal safety of the battery.

[0206] Comparative Example 2

[0207] The difference from Example 10 is that the polymer monomer does not have sulfate ester groups, and its structural formula is:

[0208]

[0209] Comparative Example 3

[0210] The difference from Example 10 is that the number of sulfate groups is 2, and the structural formula is:

[0211]

[0212] The polymer monomers, solid electrolytes, and solid batteries prepared in the above embodiments and comparative examples were subjected to performance tests, and the specific test results are shown in Table 1.

[0213] Infrared spectroscopy testing involves placing the sample to be tested on the crystal surface of the optical platform of the ATR (model is20) infrared spectrometer. The infrared ATR testing software is opened, and the test parameters are set to a resolution of 4 and a scan count of 32. After starting the instrument, the knob above the reflector is rotated to press the sample into full contact with the emission aperture below, and data acquisition begins. After the test is completed, the infrared spectral information of the sample can be obtained.

[0214] Viscosity Test: The viscosity of the organic solid electrolyte prepolymer solution was tested using an NDJ-5S digital rotary viscometer. The prepolymer solution was poured into a flat-bottomed container with a diameter greater than 60mm. The temperature of the prepolymer solution was maintained at 25℃, and the operating surface was stable and vibration-free. The instrument protective bracket was screwed into the lower end of the instrument in reverse. Using the L0 rotor, it was screwed counterclockwise into the universal joint of the instrument. The lifting knob was rotated to slowly immerse the rotor in the prepolymer solution until the rotor's liquid level mark, i.e., the groove scale, was flush with the liquid surface. The instrument was then leveled again. The rotor selection key was pressed to select the speed, and then the OK key was pressed. The rotor started rotating. After the displayed value stabilized, the stop key was pressed to read the viscosity value.

[0215] Conductivity Testing: The electrode rings that hold the electrolyte container and the PTFE single ring (acting as the electrolyte container) are placed at the bottom of the battery casing. The prepolymer solution to be tested is then dropped into the electrolyte container, ensuring the electrolyte completely fills the chamber. A stainless steel electrode plug is then placed on top, forming a 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 chamber for high-temperature curing. An AC impedance test is performed at a frequency of 1MHz-0.03Hz, and an EIS test is conducted. The ionic conductivity (σ, mS / cm) of the solid electrolyte is calculated using the formula σ = L / (R×S), where 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 the impedance meter.

[0216] Rate performance test: After resting for 10 minutes, the battery is charged at a constant current of 0.2C to 4.2V, and then kept at a constant voltage of 4.2V until the current drops to 0.05C to cut off. After resting for 10 minutes, the battery is discharged at a discharge rate of 0.2C until the battery voltage reaches the set termination voltage of 2.75V. The discharge capacity is recorded. The above steps are repeated 5 times to obtain the average discharge capacity C1 at 0.2C. The above steps are then repeated, except that the discharge rate is 3C. The charge and discharge steps are repeated 5 times to obtain the average discharge capacity C2 at 3C. The ratio of C2 to C1 is used to evaluate the rate performance.

[0217] Safety Testing: In the hot chamber experiment, the lithium batteries are fully charged and placed in the test chamber. The heating rate is set to 5℃ / min, and the batteries are heated from room temperature to 150℃ and maintained at a constant temperature for 30 minutes. The battery's performance during the experiment is evaluated by observing whether it catches fire, explodes, or leaks. If the battery catches fire, explodes, or leaks during heating, it is considered to have failed the test; otherwise, it is considered to have passed the hot chamber test. The hot chamber safety performance of 10 full batteries is tested in each batch, and the pass rate of the hot chamber safety test is calculated.

[0218] Table 1 Performance Tests

[0219]

[0220]

[0221] As shown in Table 1, the viscosity of the prepolymer solution in the examples is relatively low. The low viscosity of the prepolymer solution is beneficial to its wetting of the electrodes inside the battery and the interfacial electrochemical reaction of the active particles in the electrodes, thereby improving the interfacial stability of the solid-state battery, which is crucial for the thermal safety performance of the battery. Furthermore, the conductivity of the examples is significantly higher than that of the comparative example, exhibiting high ion conductivity and ion transport performance, which enables the full battery to exhibit good rate performance during high-rate charge and discharge, thus improving the electrochemical performance of the full battery.

[0222] Finally, it should be noted that 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.

[0223] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A polymeric monomer, characterized in that, Its general structural formula is: ； Wherein, R0 is selected from one of the following groups: , , , , , , , , ; R1, R2, R3, R4, R5, and R6 are each independently selected from acrylic groups; Among them, n1, n2, n4, n5, and n6 are each independent positive integers from 1 to 10.

2. A method for preparing the polymeric monomer according to claim 1, characterized in that, include: 2,2-dihydroxymethyl-1,3-propanediol, acrylic acid, and catalyst were mixed in the first reaction to obtain an acrylic polyol ester precursor. The acrylic polyol ester precursor and the disulfonic acid compound are mixed in a second reaction to obtain the polymer monomer.

3. The method for preparing the polymeric monomer according to claim 2, characterized in that, The molar ratio of 2,2-dihydroxymethyl-1,3-propanediol to acrylic acid is 1:2-4; The mass of the catalyst is 0.2%-2% of the total mass of the 2,2-dihydroxymethyl-1,3-propanediol and the acrylic acid; The molar ratio of the acrylic polyol ester precursor to the disulfonic acid compound is 1.8-2.2:1; The temperature of the first reaction is 50℃-90℃, and the time is 2h-12h; The second reaction is carried out at a temperature of 50℃-90℃ for 2h-12h. The catalyst is selected from dibutyl dilaurate; The disulfonic acid compound is selected from one of 1,3-propanedisulfonic acid, 1,4-butanedisulfonic acid, 1,4-piperazine diethanesulfonic acid, 1,4-piperazine dipropanesulfonic acid, 1,4-benzenedisulfonic acid, or 2,6-naphthalenedisulfonic acid.

4. A solid electrolyte, characterized in that, Its raw materials, by mass parts, include: Electrolyte 95-99 parts, polymer monomer 1-5 parts, initiator 0.003-0.15 parts; The polymeric monomer includes the polymeric monomer of claim 1; The electrolyte is made from lithium salt and organic solvent.

5. The solid electrolyte according to claim 4, characterized in that, The electrolyte lithium salt is selected from one or more of methyl ethyl carbonate, ethylene carbonate, propylene carbonate, fluoroethylene carbonate, propane sulpholactone, and vinyl sulfate.

6. The solid electrolyte according to claim 4, characterized in that, The electrolyte lithium salt is selected from one or more of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium difluorophosphate, and lithium difluorooxalate borate.

7. The solid electrolyte according to claim 4, characterized in that, The raw materials for the electrolyte, based on a total mass of 100%, include: Electrolyte lithium salt 10%-20%, organic solvent 80%-90%.

8. The solid electrolyte according to claim 4, characterized in that, The initiator is selected from azo compounds.

9. The solid electrolyte according to claim 4, characterized in that, The viscosity of the solid electrolyte is 2 mPas-7 mPas.

10. A method for preparing a solid electrolyte according to any one of claims 4-9, characterized in that, include: The raw materials for the solid electrolyte are mixed in a third step to prepare the solid electrolyte.

11. The method for preparing a solid electrolyte according to claim 10, characterized in that, The relative humidity of the third mixture is less than or equal to 2%; The dew point temperature of the third mixture is less than or equal to -40°C.

12. A lithium-ion battery, characterized in that, Includes the solid electrolyte as described in any one of claims 4-9.

13. An electrical appliance, characterized in that, Including the lithium-ion battery of claim 12.

Images