Compound, preparation method and application thereof, lithium ion battery electrolyte additive and electrolyte

Abstract

The invention relates to a compound, a preparation method and application thereof, a lithium ion battery electrolyte additive and an electrolyte, relates to the technical field of lithium ion batteries, and provides a compound which contains a special double-ring structure and is shown as a formula (I) and can be applied to preparation of the lithium ion battery electrolyte additive and the electrolyte. The low-temperature discharge performance, the rate capability and the safety performance of the lithium ion battery working at 4.5 V can be remarkably improved, the lithium ion battery has a relatively good application prospect in a high-voltage system, and the defects in the prior art are overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a compound, a preparation method and application thereof, a lithium ion battery electrolyte additive and an electrolyte. Background Art

[0002] As the global demand for clean energy and high-performance energy storage devices continues to grow, lithium-ion batteries play a vital role in electric vehicles, portable electronic devices, and large-scale energy storage systems. In these application scenarios, improving the energy density and operating voltage of lithium-ion batteries has become a key research goal. High-voltage lithium-ion batteries can significantly improve the energy storage capacity of batteries without increasing the size and weight of the batteries, thereby meeting the market's demand for long driving range and long-term use.

[0003] The electrolyte of traditional lithium-ion batteries is usually lithium hexafluorophosphate (LiPF 6 ) is a lithium salt and a system composed of a carbonate mixed solvent (such as ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), etc.). However, this traditional electrolyte has serious problems under high voltage environment. When the battery operating voltage exceeds 4.3V, carbonate solvents will undergo oxidative decomposition on the positive electrode surface due to their poor electrochemical stability under high voltage. This oxidative decomposition reaction can lead to a series of adverse consequences, including decomposition of the electrolyte, gas generation, and intensified side reactions between the positive electrode material and the electrolyte. These problems will not only cause rapid decay of battery capacity, but may also cause safety hazards such as battery bulging and thermal runaway, which seriously limit the application of lithium-ion batteries under high voltage.

[0004] Fluorinated solvents are a type of solvent developed to improve the high-voltage resistance of electrolytes. They change the electron cloud distribution of solvent molecules by introducing fluorine atoms, thereby improving their antioxidant capacity. However, fluorinated solvents have some obvious disadvantages. On the one hand, the synthesis process of fluorinated solvents is usually more complicated, requiring the use of special fluorine-containing raw materials and more stringent reaction conditions, which makes their production costs high. On the other hand, fluorinated solvents are more sensitive to impurities, especially water and acidic impurities. Even trace amounts of water or acid can trigger decomposition reactions of fluorinated solvents, thereby affecting the performance of the electrolyte. In addition, the performance of some fluorinated solvents at low temperatures is also unsatisfactory, and their viscosity will increase significantly, affecting the transmission efficiency of lithium ions in the electrolyte, thereby reducing the performance of the battery in low temperature environments.

[0005] Sulfone solvents have high electrochemical stability and can withstand high voltages, so they are considered to be a potential high-voltage resistant solvent. However, sulfone solvents also have their own shortcomings. The viscosity of sulfone solvents is relatively high, especially in low temperature environments, where the viscosity rises sharply, which greatly hinders the migration of lithium ions, resulting in a significant decrease in the charge and discharge performance of the battery under low temperature conditions. At the same time, there are compatibility issues between sulfone solvents and electrode materials. During long-term charging and discharging processes, sulfone solvents may react with the positive electrode material, resulting in structural destruction of the positive electrode material and dissolution of transition metal ions. These dissolved ions may migrate to the negative electrode, destroying the solid electrolyte interface film (SEI film) of the negative electrode, further affecting the cycle life and performance of the battery.

[0006] Nitrile solvents have attracted attention for their high dielectric constant and good solubility in lithium salts, and can improve the high-voltage resistance of electrolytes to a certain extent. However, nitrile solvents have great safety hazards and are highly flammable, which can easily cause fires or even explosions during battery use, especially under abnormal conditions such as high temperature, overcharge or short circuit. In addition, some nitrile solvents are also toxic to a certain extent, posing a threat to the production environment and the health of operators, which requires strict protective measures to be taken during production and use, increasing production costs and operating difficulties.

[0007] In summary, although certain research results have been achieved in the field of high-voltage solvent resistance, there are still many problems. It is necessary to further develop new high-voltage lithium-ion battery electrolyte technologies to overcome these shortcomings in order to meet the development needs of high-energy density and high-safety lithium-ion batteries. Summary of the invention

[0008] In order to solve the above problems, the present invention provides a compound and a preparation method and application thereof, a lithium ion battery electrolyte additive and an electrolyte.

[0009] In a first aspect, the present invention provides a compound, the chemical structure of the compound is shown in formula (I);

[0010] The formula (I):

[0011] In a second aspect, the present invention provides a method for preparing the compound according to any one of the first aspect, the preparation method comprising the following steps:

[0012] Dissolving decalin and bromine in a first solvent and performing a first reaction under light conditions to obtain a first product;

[0013] dissolving the first product, ethyl p-toluenesulfonylcarbamate and a base in a second solvent to carry out a second reaction to obtain a second product;

[0014] The second product is subjected to a third reaction in a potassium permanganate / sulfuric acid system, and after the third reaction, sodium hydroxide is added to carry out a fourth reaction to obtain a third product;

[0015] dissolving the third product and sodium azide in a third solvent to carry out a fifth reaction to obtain a fourth product;

[0016] dissolving the fourth product and lithium aluminum hydride in a fourth solvent to carry out a sixth reaction, and adding hydrochloric acid after the sixth reaction to carry out a seventh reaction to obtain a fifth product;

[0017] dissolving the fifth product in a fifth solvent and adding an initiator to carry out an eighth reaction to obtain a sixth product;

[0018] Adding the sixth product to a strong alkaline solution to carry out a ninth reaction to obtain a seventh product;

[0019] The seventh product is added into a potassium dichromate / sulfuric acid system to carry out a tenth reaction to obtain the compound.

[0020] Further, the working condition parameters of the first reaction include: the molar ratio of the decalin to the bromine is 1:(1.0-1.3), the temperature is 24-28° C., the time is 2-3 hours, the first solvent includes carbon tetrachloride, the illumination uses a mercury lamp, and the illumination parameters of the mercury lamp include: the illumination power is 100-200W, and the illumination distance is 10-20cm;

[0021] The working condition parameters of the second reaction include: the molar ratio of the first product, the ethyl p-toluenesulfonylcarbamate and the base is 1:(1.0-1.3):(1.2-2.0), the base includes potassium carbonate, the second solvent includes dimethylformamide, the temperature is 60-70° C., and the time is 4-6 hours;

[0022] The working condition parameters of the third reaction include: the molar ratio of the second product, the potassium permanganate, and the sulfuric acid is 1:(1.2-1.8):(2-3), the temperature is 24-28° C., and the time is 3-4 hours;

[0023] The working condition parameters of the fourth reaction include: the molar amount of the sodium hydroxide added is 1.5 to 2.5 times the molar amount of the second product, the temperature is 80 to 90° C., and the time is 2 to 3 hours;

[0024] The working condition parameters of the fifth reaction include: the molar ratio of the third product to the sodium azide is 1:(1.0-1.5), the temperature is 80-90° C., the time is 4-6 hours, and the third solvent includes dimethyl sulfoxide;

[0025] The working condition parameters of the sixth reaction include: the molar ratio of the fourth product to the lithium aluminum hydride is (1.0-1.2):(1.0-1.2), the fourth solvent includes anhydrous ether, the temperature is -15--8°C, and the time is 3-4 hours;

[0026] The working condition parameters of the seventh reaction include: the molar amount of the hydrochloric acid is 1 to 2 times the molar amount of the fourth product, the temperature is 50 to 60° C., and the time is 2 to 3 hours;

[0027] The working condition parameters of the eighth reaction include: a temperature of 40 to 50° C., a time of 4 to 6 hours, the initiator is composed of N-bromosuccinimide and benzoyl peroxide, the molar ratio of the N-bromosuccinimide, the benzoyl peroxide and the fifth product is (10 to 20):1:(8 to 12), and the fifth solvent includes dichloromethane;

[0028] The working condition parameters of the ninth reaction include: the molar ratio of the sixth product to the strong base is 1:(1.5-3), the strong base includes sodium hydroxide, the temperature is 80-90° C., and the time is 6-8 hours;

[0029] The working condition parameters of the tenth reaction include: the molar ratio of the seventh product, the potassium dichromate and the sulfuric acid is 1:(1.2-2.0):(3-4), the temperature is 60-70°C, and the time is 3-4 hours.

[0030] Further, the working condition parameters of the first reaction include: the molar ratio of the decalin to the bromine is 1:1.2, the temperature is 25° C., the time is 2 to 3 hours, the first solvent includes carbon tetrachloride, the illumination is a mercury lamp, and the illumination parameters of the mercury lamp include: the illumination power is 150W, and the illumination distance is 15 cm;

[0031] The working condition parameters of the second reaction include: the molar ratio of the first product, the ethyl p-toluenesulfonylcarbamate and the base is 1:1.2:1.5, the base includes potassium carbonate, the second solvent includes dimethylformamide, the temperature is 60-70° C., and the time is 4-6 hours;

[0032] The working condition parameters of the third reaction include: the molar ratio of the second product, the potassium permanganate, and the sulfuric acid is 1:1.5:(2-3), the temperature is 24-28° C., and the time is 3-4 hours;

[0033] The working condition parameters of the fourth reaction include: the molar amount of the sodium hydroxide added is twice the molar amount of the second product, the temperature is 80-90° C., and the time is 2-3 hours;

[0034] The working condition parameters of the fifth reaction include: the molar ratio of the third product to the sodium azide is 1:1.2, the temperature is 80-90° C., the time is 4-6 hours, and the third solvent includes dimethyl sulfoxide;

[0035] The working condition parameters of the sixth reaction include: the molar ratio of the fourth product to the lithium aluminum hydride is 1:1, the fourth solvent includes anhydrous ether, the temperature is -10°C, and the time is 3 to 4 hours;

[0036] The working condition parameters of the seventh reaction include: the molar amount of the hydrochloric acid is 1.5 times the molar amount of the fourth product, the temperature is 50-60° C., and the time is 2-3 hours;

[0037] The working condition parameters of the eighth reaction include: a temperature of 40 to 50° C., a time of 4 to 6 hours, the initiator is composed of N-bromosuccinimide and benzoyl peroxide, the molar ratio of the N-bromosuccinimide, the benzoyl peroxide and the fifth product is 12:1:10, and the fifth solvent includes dichloromethane;

[0038] The working condition parameters of the ninth reaction include: the molar ratio of the sixth product to the strong base is 1:2, the strong base includes sodium hydroxide, the temperature is 80-90° C., and the time is 6-8 hours;

[0039] The working condition parameters of the tenth reaction include: the molar ratio of the seventh product, the potassium dichromate and the sulfuric acid is 1:1.5:(3-4), the temperature is 60-70°C, and the time is 3-4 hours.

[0040] In a third aspect, the present invention provides a use of the compound described in any one of the first aspect and the second aspect in the preparation of a lithium ion battery electrolyte additive and an electrolyte.

[0041] In a fourth aspect, the present invention provides an additive for lithium-ion battery electrolyte, wherein the additive for lithium-ion battery electrolyte is the compound described in any one of the first aspect and the second aspect.

[0042] In a fifth aspect, the present invention provides an electrolyte, comprising the compound described in any one of the first aspect and the second aspect.

[0043] Further, the electrolyte comprises a lithium salt, an anhydrous organic solvent, the compound described in any one of the first aspect and the second aspect, and a second additive;

[0044] The molar concentration of the lithium salt in the electrolyte is 0.8M-1.4M;

[0045] In terms of weight percentage, the amount of the anhydrous organic solvent accounts for 60-80% of the total weight of the electrolyte;

[0046] In terms of weight percentage, the amount of the compound is 0.1 to 10% of the total weight of the electrolyte;

[0047] In terms of weight percentage, the amount of the second additive is 0.1 to 20% of the total weight of the electrolyte;

[0048] The second additive includes at least one of tris(trimethylsilyl)borate, lithium bis(oxalatoborate), lithium bis(fluorooxalatoborate), tetramethyl borate, trimethyl borate, trimethylcyclotriboroxane, tris(2,2,2-trifluoroethyl)phosphite, triphenylphosphite, tris(trimethylsilyl)phosphite, trimethyl phosphite, vinylene carbonate, fluoroethylene carbonate, 1,3-propane sultone, succinic anhydride, 5-hydroxy-1H-indazole, phenyl maleic anhydride, hexabutylcyclohexane-1,2,3,4,5,6-hexylamine, acetylenic silylpyridine compound, triphenyl phosphite, bismaleimide, triallyl phosphate, dimethanesulfonyl methane, trifluoromethylphenyl sulfide, perfluoroalkyl-substituted ethylene carbonate, ethyl 2,2-difluoroacetate, and pentafluoroethoxycyclotriphosphazene.

[0049] Furthermore, in terms of weight percentage, the amount of the compound is 0.1 to 5% of the total weight of the electrolyte, the lithium salt includes at least one of lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, and the anhydrous organic solvent includes at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propionate, ethyl butyrate, γ-butyrolactone, dimethoxyethane, tetrahydrofuran, cyclopentane, fluoromethyl-substituted ethylene carbonate, perfluorobutyl-substituted ethylene carbonate, perfluorohexyl-substituted ethylene carbonate, perfluorooctyl-substituted ethylene carbonate, methyl acetate and ethyl propionate.

[0050] Furthermore, in terms of weight percentage, the amount of the compound is 0.1-2% of the total weight of the electrolyte; the electrolyte is a high-voltage lithium-ion battery electrolyte, and the working voltage of the high-voltage lithium-ion battery electrolyte is 2.75-4.5V.

[0051] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0052] The present invention provides a compound as shown in formula (I) containing a special bicyclic structure (named 3,7-dioxo-1,5-diazabicyclo[3.3.1]nonane-2,6-dione), which can be used to prepare lithium ion battery electrolyte additives and electrolytes, and can significantly improve the low-temperature discharge performance, rate performance and safety performance of lithium ion batteries when working at 4.5V, and has a good application prospect in high voltage systems, making up for the shortcomings of the prior art. Specifically:

[0053] 3,7-Dioxo-1,5-diazabicyclo[3.3.1]nonane-2,6-dione has unique structural advantages and can improve battery performance. Its bicyclic structure is stable and can resist electron impact and energy transfer under high voltage, reduce molecular deformation and chemical bond breakage, and heteroatoms participate in conjugation or hydrogen bond networks, enhance stability, disperse energy, and reduce the possibility of decomposition reactions. Nitrogen and oxygen heteroatoms have electron donating ability and can react with oxidizing species to resist oxidation.

[0054] In terms of interaction with electrode materials, heteroatoms interact with the electrode surface, nitrogen atoms can form coordination bonds, and oxygen atoms have hydrogen bonds or electrostatic effects to form a stable adsorption layer, reduce side reactions, and enhance adhesion. The double ring structure produces steric hindrance, preventing the active sites from contacting the undesirable parts of the additives, reducing the probability of side reactions.

[0055] Regarding the internal resistance of the battery, based on heteroatoms and conjugated systems, a conductive interface layer can be formed on the electrode surface to reduce the internal resistance, and a uniform protective film can be formed to reduce the increase in local internal resistance. The double ring structure and the lithium ion transmission channels around the heteroatoms can improve the transmission efficiency and further reduce the internal resistance.

[0056] In terms of battery capacity, the steric hindrance and adsorption of the double ring structure can protect the electrode active sites, and the heteroatoms may repair the damaged sites. It can also enhance the stability of electrode materials, inhibit the dissolution of active substances, and increase battery capacity.

[0057] In terms of solubility, the molecular polar functional groups and their reasonable distribution make it soluble at different voltages and not easy to precipitate. The heteroatoms can form hydrogen bonds or complexes with the electrolyte components to improve stability and solubility.

[0058] In terms of viscosity, its structure is simple, its contribution to the viscosity of the electrolyte is small, and its molecular size is moderate, which helps to maintain good fluidity of the electrolyte and reduce the impact on charge and discharge performance. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0061] The present invention aims to solve the technical problems faced by high-voltage lithium-ion battery electrolytes, mainly involving the following aspects:

[0062] Improve the aggravation of decomposition reaction: When designing the molecular structure of the additive, choose chemical bonds with higher bond energy to construct the main chain and key functional groups. Introduce suitable substituents in the molecule to produce a steric hindrance effect to prevent the active site from being over-attacked. Introduce functional groups with antioxidant ability. These functional groups can preferentially react with the active oxygen species generated in the high voltage environment, and they themselves are oxidized to protect the main structure of the additive molecule and avoid the occurrence of decomposition reactions. Design a combination of functional groups that can undergo reversible redox reactions. Under high voltage, when the additive is threatened by oxidation, these functional groups can consume excess electrons through their own redox regulation to maintain the chemical stability of the additive.

[0063] Improve side reactions with electrode materials: According to the surface properties of the electrode materials, design additives with matching functional groups. Design additives with flexible structures so that the interface layer formed on the electrode surface can adapt to the volume changes of the electrode material during the charge and discharge process. This can avoid the exposure of new active sites due to the rupture or peeling of the interface layer, thereby reducing the possibility of side reactions. Introduce specific adsorption sites in the additive molecules so that they can be selectively adsorbed at specific locations on the electrode surface to avoid unnecessary reactions with the active ingredients in the electrode material. By adjusting the ratio of the polar and non-polar parts in the molecular structure of the additive, its adsorption strength on the electrode surface is controlled. Moderate adsorption strength can not only ensure the effective coverage of the additive on the electrode surface, but also allow the smooth transmission of lithium ions during the charge and discharge process, while reducing side reactions caused by excessive adsorption.

[0064] Improve the impact on the internal resistance of the battery: Design the protective film formed by the additive on the electrode surface to have good conductivity. Design the structure and reaction kinetics of the additive to form a protective film of uniform thickness and appropriate thickness on the electrode surface. Construct lithium ion transmission channels in the additive molecules, or introduce porous structures with specific pore sizes and chemical environments to enable lithium ions to quickly pass through the protective film and reduce the internal resistance of the battery. Adjust the molecular structure of the additive so that its adsorption energy for lithium ions is moderate. Too low adsorption energy may cause lithium ions to be unable to be effectively fixed by the protective film, while too high adsorption energy will hinder the transmission of lithium ions. By optimizing the molecular structure to find a balance point, the transmission efficiency of lithium ions in the protective film can be improved.

[0065] Improve the impact on battery capacity: Introduce steric hindrance structures into additive molecules to prevent the active sites of electrode materials from being occupied or destroyed by other substances. Design functional groups that can react chemically with active ingredients in electrode materials. When the active sites of the electrode are damaged, the additives can react with them and repair the active sites, restoring the specific capacity of the electrode material. Design additives that can form chemical bonds or physical adsorption with electrode materials to enhance the structural stability of electrode materials. For positive electrode materials, design additives that can inhibit the dissolution of active substances under high voltages. Additives can form coordination complexes with transition metal ions on the surface of positive electrode materials to fix metal ions on the electrode surface, reduce the loss of active substances, and increase battery capacity.

[0066] Improve solubility changes: If the solubility of the additive decreases at high voltage due to polarity issues, the polarity of the molecule can be appropriately increased. Rationally design the distribution of the polar and non-polar parts of the molecule so that the additive can maintain good solubility at different voltages. Design additives that can form hydrogen bonds or complexes with components in the electrolyte to improve their stability and solubility in the electrolyte. By adjusting the molecular structure of the additive, its solvation effect is affected. For example, the additive is designed to have a suitable molecular size and shape so that it can form a good solvation layer in the electrolyte, improve solubility, and avoid precipitation due to poor solvation.

[0067] Improve viscosity change: Design the molecular structure of the additive to be as simple and linear as possible, avoid too many side chains and complex ring structures, so as to reduce its own contribution to the viscosity of the electrolyte. Keep the size of the additive molecule moderate, avoid being too large or too small. Too large molecules tend to form aggregates and increase viscosity; too small molecules may not play an effective additive role. By rationally designing the molecular structure and controlling its molecular weight within an appropriate range, the impact on the viscosity of the electrolyte can be reduced. Introduce functional groups that can adjust the rheological properties of the electrolyte into the additive molecules. Design additives to form micelles or microemulsion structures in the electrolyte. These structures can reduce the macroscopic viscosity of the electrolyte while ensuring the uniform dispersion and effective effect of the additives in the electrolyte.

[0068] The technical solution provided by the present invention is as follows:

[0069] In a first aspect, the present invention provides a compound, the chemical structure of the compound is shown in formula (I);

[0070] The formula (I):

[0071] The embodiment of the present invention provides a compound. On the basis of the existing compound, the present invention introduces an appropriate amount of holmium and zirconium boride. The components work together to improve the high temperature resistance and other properties of the compound. At a temperature of 700°C, the hardness of the obtained compound can be maintained at 720-840HV, which can meet the use requirements in high temperature environments and make up for the shortcomings of the existing technology. Specifically:

[0072] 3,7-Dioxo-1,5-diazabicyclo[3.3.1]nonane-2,6-dione has a relatively rigid bicyclic structure, which can provide a certain stability and reduce the chemical bond breakage caused by molecular deformation under high voltage. Compared with some linear or flexible structured compounds, its bicyclic structure can better resist the electron impact and energy transfer under high voltage environment, thereby reducing the possibility of decomposition reaction. The nitrogen and oxygen heteroatoms in the molecule can participate in the formation of conjugated system or hydrogen bond network, further enhancing the stability of the molecule. These heteroatoms can disperse the energy that may be concentrated on certain chemical bonds under high voltage through electron delocalization or hydrogen bond interaction, making the molecule as a whole more resistant to high voltage environment and reducing the occurrence of decomposition reaction. Nitrogen and oxygen heteroatoms have a certain electron donating ability. In a high voltage system, they can act as electron donors to react with the generated oxidizing species (such as free radicals, etc.), thereby consuming these oxidizing substances and protecting their own structure from oxidative decomposition. For example, the lone pair of electrons on the nitrogen atom participates in this antioxidant process, which is similar to the mechanism of action of some nitrogen-containing antioxidants.

[0073] The nitrogen and oxygen heteroatoms in the molecule interact with the electrode surface (especially the transition metal ions present on the surface of the positive electrode material). For example, nitrogen atoms form coordination bonds with transition metal ions, and oxygen atoms bind to the electrode surface through hydrogen bonds or weak electrostatic interactions. This interaction helps the additive form a stable adsorption layer on the electrode surface, reducing adverse chemical reactions between the additive and the electrode material. It also enhances the adhesion of the additive to the electrode surface and prevents it from falling off during charging and discharging. The bicyclic structure of 3,7-dioxo-1,5-diazabicyclo[3.3.1]nonane-2,6-dione will produce a certain steric hindrance effect, preventing the active sites on the surface of the electrode material from directly contacting the part of the additive molecule that causes side reactions. For example, if there are some active groups on the surface of the electrode material that are easy to react with the additive, the bicyclic structure can spatially hinder the interaction between them, thereby reducing the probability of side reactions.

[0074] Based on the possibility of heteroatoms and conjugated systems in its structure, the additive helps to form an interface layer with a certain conductivity on the electrode surface. For example, in the adsorption layer formed on the electrode surface, electron conduction channels can be formed between heteroatoms or between heteroatoms and metal ions on the electrode surface, which can reduce the internal resistance of the battery. The formation of this conductive interface layer is similar to the conductive layer formed on the electrode surface by some metal organic complexes, which can promote the transmission of electrons and improve the charging and discharging efficiency of the battery. Due to its relatively rigid structure and specific molecular shape, 3,7-dioxo-1,5-diazabicyclo[3.3.1]nonane-2,6-dione forms a relatively uniform protective film on the electrode surface. Compared with some additives with irregular structures, its adsorption and reaction process on the electrode surface is more orderly, thereby reducing the problem of increased local internal resistance caused by uneven film. There are some channel structures suitable for lithium ion transmission inside the bicyclic structure and around heteroatoms. For example, lithium ions are transmitted through the space near nitrogen and oxygen heteroatoms, and these heteroatoms can guide the movement of lithium ions through electrostatic effects. This potential ion channel structure is similar to the promotion of lithium ion transport by some porous materials with specific pore sizes and chemical environments, which can improve the transmission efficiency of lithium ions between the electrode surface and the electrolyte, thereby reducing the internal resistance of the battery.

[0075] The steric hindrance of the bicyclic structure and its adsorption on the electrode surface can prevent the active sites of the electrode material from being occupied or destroyed by other substances. For example, it can cover the electrode active sites to form a physical barrier to prevent impurities in the electrolyte or other substances that may react with the active sites from approaching. At the same time, its adsorption on the electrode surface can also stabilize the chemical environment of the electrode surface, which is beneficial for the electrode material to maintain its activity, thereby increasing the battery capacity. The nitrogen and oxygen atoms in the molecule have certain chemical activity. When the electrode active site is damaged, they may react with the damaged site and play a certain repair role. For example, if the metal ions on the electrode surface undergo some chemical changes, the nitrogen atoms stabilize the metal ions by forming coordination bonds, restore the activity of the electrode material, and thus increase the battery capacity. Through interactions with the surface of the electrode material (such as the coordination bonds and hydrogen bonds mentioned above), 3,7-dioxo-1,5-diazabicyclo[3.3.1]nonane-2,6-dione can enhance the structural stability of the electrode material. For some electrode materials that are prone to structural changes during the charge and discharge process (such as silicon-based negative electrode materials or phase changes of certain positive electrode materials under high voltage, etc.), this combination can reduce the volume expansion, pulverization or other structural damage of the material, thereby increasing the battery capacity. For positive electrode materials, heteroatoms in the molecules may form stable complexes with transition metal ions in the active material, thereby inhibiting the dissolution of the active material under high voltage. For example, in the case of lithium cobalt oxide positive electrode materials, nitrogen and oxygen heteroatoms coordinate with cobalt ions to fix the cobalt ions on the electrode surface, reducing the dissolution loss of cobalt and increasing the battery capacity.

[0076] The nitrogen and oxygen heteroatoms in the 3,7-dioxo-1,5-diazabicyclo[3.3.1]nonane-2,6-dione molecule and the functional groups such as carbonyl groups give the molecule a certain polarity. This polarity helps to improve the solubility of the additive in the electrolyte, making it less likely to precipitate due to reduced solubility at high voltages. Compared with some non-polar or low-polar compounds, it is more able to interact with the polar components in the electrolyte and maintain a good solubility state. The structural characteristics of the molecule make the distribution of polar functional groups in the molecule relatively reasonable, which is conducive to maintaining good solubility at different voltages. For example, the bicyclic structure affects the overall polarity distribution of the molecule, so that when the polarity of the electrolyte changes (such as some changes in the electrolyte composition that may occur at high voltages), the additive can still adapt to this change, maintain good solubility, and avoid problems such as electrode blockage caused by solubility problems. The nitrogen and oxygen heteroatoms in the molecule can form hydrogen bonds or complexes with the components in the electrolyte. For example, it forms hydrogen bonds or complexes with anions in lithium salts or certain functional groups in organic solvents, thereby improving its stability and solubility in the electrolyte. This interaction is similar to the mechanism by which some small molecule additives improve their solubility through specific interactions with electrolyte components, which helps to maintain the uniform dispersion of additives in the electrolyte and avoid precipitation.

[0077] The relatively simple structure of 3,7-dioxo-1,5-diazabicyclo[3.3.1]nonane-2,6-dione (compared to some complex multi-branched or multi-ring compounds) contributes little to the viscosity of the electrolyte. Its bicyclic structure and relatively few branched structures make the interaction between molecules relatively weak, and will not cause a significant increase in electrolyte viscosity due to entanglement or aggregation between molecules. The molecular size of this compound is moderate, and it will not easily form agglomerates to increase viscosity due to excessively large molecules, nor will it be unable to play an effective additive role due to too small molecules. This moderate molecular size helps to maintain good fluidity of the electrolyte at high voltage and reduce the impact on the charge and discharge performance of the battery.

[0078] In a second aspect, the present invention provides a method for preparing the compound according to any one of the first aspect, the preparation method comprising the following steps:

[0079] Decalane (10 mmol) and bromine (12 mmol) are reacted in carbon tetrachloride (50 mL) under light irradiation conditions. A mercury lamp can be used for light irradiation. The reaction temperature is maintained at room temperature (about 25° C.) and the reaction time is 2-3 hours.

[0080] The product obtained in the previous step (10 mmol) was reacted with ethyl p-toluenesulfonylcarbamate (12 mmol) in dimethylformamide (30 mL) in the presence of potassium carbonate (15 mmol) as a base. The reaction temperature was set at 60-70° C. and the reaction time was 4-6 hours.

[0081] Potassium permanganate (15 mmol) was used to carry out oxidation reaction of the product (10 mmol) obtained in the previous step in sulfuric acid (10 mL, concentration of 2-3 mol / L). The oxidation reaction was carried out at room temperature for 3-4 hours. After the reaction was completed, sodium hydroxide (20 mmol) was added to carry out elimination reaction under heating conditions (80-90° C.) for 2-3 hours.

[0082] The product obtained in the previous step (10 mmol) was reacted with sodium azide (12 mmol) in dimethyl sulfoxide (20 mL) under heating conditions (80-90° C.) for 4-6 hours.

[0083] The product (10 mmol) obtained in the previous step was subjected to reduction reaction using lithium aluminum hydride (10 mmol) in anhydrous ether (30 mL) at low temperature (-10° C.) for 3-4 hours. After the reaction was completed, hydrochloric acid (10 mL, concentration of 1-2 mol / L) was used for treatment under heating conditions (50-60° C.) to promote the rearrangement reaction for 2-3 hours.

[0084] After the reaction was completed, the reaction mixture was initially separated by extraction. The reaction mixture was extracted three times with ethyl acetate (50 mL), the organic phases were combined, and then insoluble impurities were removed by filtration.

[0085] The product obtained in the previous step (10 mmol) was dissolved in dichloromethane (50 mL), and N-bromosuccinimide (NBS, 15 mmol) and benzoyl peroxide (BPO, 1.5 mmol, as an initiator) were added. The reaction was carried out under heating reflux conditions at a temperature of about 40-50° C. for a reaction time of 4-6 hours.

[0086] The product obtained in the previous step (10 mmol) was added to a sodium hydroxide aqueous solution (30 mmol of NaOH dissolved in 60 mL of water) and hydrolyzed under heating conditions (80-90° C.) for 6-8 hours.

[0087] The product obtained in the previous step (10 mmol) was added to a mixed solution of potassium dichromate (20 mmol) and sulfuric acid (15 mL, concentration of 3-4 mol / L), and an oxidation reaction was carried out under heating conditions (60-70° C.) for 3-4 hours.

[0088] After the reaction was completed, the reaction mixture was first cooled to room temperature and then initially separated by extraction. The reaction mixture was extracted three times with ethyl acetate (50 mL), the organic phases were combined, and then insoluble impurities were removed by filtration to obtain the compound, which was characterized by nuclear magnetic resonance, infrared, etc. and proved to be consistent with the chemical structure of the compound.

[0089] In a third aspect, the present invention provides a use of the compound described in any one of the first aspect and the second aspect in the preparation of a lithium ion battery electrolyte additive and an electrolyte.

[0090] In a fourth aspect, the present invention provides an additive for lithium-ion battery electrolyte, wherein the additive for lithium-ion battery electrolyte is the compound described in any one of the first aspect and the second aspect.

[0091] In a fifth aspect, the present invention provides an electrolyte, comprising the compound described in any one of the first aspect and the second aspect.

[0092] In some specific embodiments, the electrolyte includes a lithium salt, an anhydrous organic solvent, the compound described in any one of the first aspect and the second aspect, and a second additive;

[0093] The molar concentration of the lithium salt in the electrolyte is 0.8M-1.4M;

[0094] In terms of weight percentage, the amount of the anhydrous organic solvent accounts for 60-80% of the total weight of the electrolyte;

[0095] In terms of weight percentage, the amount of the compound is 0.1 to 10% of the total weight of the electrolyte;

[0096] In terms of weight percentage, the amount of the second additive is 0.1 to 20% of the total weight of the electrolyte;

[0097] The second additive includes tris(trimethylsilyl)borate (TMSB), lithium bis(oxalatoborate) (LiBOB), lithium bis(fluorooxalatoborate) (LiDFOB), tetramethylborate (TMB), trimethyl borate (TB), trimethylcyclotriboroxane, tris(2,2,2-trifluoroethyl)phosphite (TFEP), triphenylphosphite (TPP), tris(trimethylsilyl)phosphite (TMPS), trimethyl phosphite (TMP), vinylene carbonate (VC), fluoroethylene carbonate (FEC), 1,3-propane sultone (PS), succinic anhydride, 5-hydroxy- At least one of 1H-indazole (HI), phenyl maleic anhydride (PMA), hexabutylcyclohexane-1,2,3,4,5,6-hexylamine (HBCCHI), acetylenic silyl pyridine compounds, triphenyl phosphite (TPPi), bismaleimide (BMI), triallyl phosphate (TAP), dimethanesulfonyl methane (DMSM), trifluoromethylphenyl sulfide (PTS), perfluoroalkyl-substituted ethylene carbonate (such as TEM-EC, PFB-EC, PFH-EC, PFO-EC, etc.), ethyl 2,2-difluoroacetate (DFEA), and pentafluoroethoxycyclotriphosphazene (FPN).

[0098] In some specific embodiments, the amount of the compound is 0.1-5% of the total weight of the electrolyte, the lithium salt includes at least one of lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, and the anhydrous organic solvent includes at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propionate, ethyl butyrate, γ-butyrolactone, dimethoxyethane, tetrahydrofuran, cyclopentane, fluoromethyl-substituted ethylene carbonate, perfluorobutyl-substituted ethylene carbonate, perfluorohexyl-substituted ethylene carbonate, perfluorooctyl-substituted ethylene carbonate, methyl acetate and ethyl propionate.

[0099] In some specific embodiments, the amount of the compound is 0.1-2% of the total weight of the electrolyte in terms of weight percentage; the electrolyte is a high-voltage lithium-ion battery electrolyte, and the operating voltage of the high-voltage lithium-ion battery electrolyte is 2.75-4.5V.

[0100] The raw materials involved in the compounds provided in the embodiments of the present invention and their preparation methods and applications, unless otherwise specified or described, can be directly commercially available products or can be prepared in-house according to existing public preparation methods; at the same time, the operating steps involved in the preparation methods, unless otherwise specified or described, can be carried out according to conventional preparation methods in the art or using existing equipment, and will not be described one by one here.

[0101] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0102] Example 1

[0103] This example provides a compound, the chemical structure of the compound is shown in formula (I);

[0104] The formula (I):

[0105] The preparation method of the above compound comprises the following steps:

[0106] Step (1): reacting decalin (10 mmol) and bromine (12 mmol) in carbon tetrachloride (50 mL) under illumination conditions, using a mercury lamp, the illumination power of the mercury lamp is 150 W, the illumination distance is 15 cm, the reaction temperature is maintained at room temperature (about 25° C.), and the reaction time is 2.5 hours to obtain a first product;

[0107] Step (2): reacting the first product (10 mmol) obtained in step (1) with ethyl p-toluenesulfonylcarbamate (12 mmol) in dimethylformamide (30 mL) in the presence of potassium carbonate (15 mmol) as a base, with the reaction temperature set at 65° C. and the reaction time being 5 hours to obtain a second product;

[0108] Step (3): using potassium permanganate (15 mmol) in sulfuric acid (10 mL, concentration of 2.5 mol / L) to carry out an oxidation reaction on the second product (10 mmol) obtained in step (2), the oxidation reaction being carried out at room temperature for 3.5 hours; after the reaction is completed, sodium hydroxide (20 mmol) is directly added to the reaction system to carry out an elimination reaction under heating conditions (85° C.) for 2.5 hours to obtain a third product;

[0109] Step (4): reacting the third product (10 mmol) obtained in step (3) with sodium azide (12 mmol) in dimethyl sulfoxide (20 mL) under heating conditions (85° C.) for 5 hours to obtain a fourth product;

[0110] Step (5): using lithium aluminum hydride (10 mmol) in anhydrous ether (30 mL) to reduce the fourth product (10 mmol) obtained in step (4) at low temperature (-10° C.) for 3.5 hours; after the reaction is completed, directly adding hydrochloric acid (10 mL, concentration of 1.5 mol / L) to the reaction system and treating it under heating conditions (55° C.) to promote the rearrangement reaction, and the treatment time is 2.5 hours; after the reaction is completed, the reaction mixture is preliminarily separated by an extraction method, and the reaction mixture is extracted three times with ethyl acetate (50 mL), the organic phases are combined, and insoluble impurities are removed by filtration to obtain the fifth product;

[0111] Step (6): dissolving the fifth product (10 mmol) obtained in step (5) in dichloromethane (30 mL), adding N-bromosuccinimide (NBS, 12 mmol) and benzoyl peroxide (BPO, 1 mmol, as an initiator); the reaction was carried out under heating reflux conditions at a temperature of 45° C. for a reaction time of 5 hours to obtain a sixth product;

[0112] Step (7): adding the sixth product (10 mmol) obtained in step (6) to a sodium hydroxide aqueous solution (20 mmol of NaOH dissolved in 50 mL of water), and performing a hydrolysis reaction under heating conditions (85° C.) for 7 hours to obtain a seventh product;

[0113] Step (8): The seventh product (10 mmol) obtained in step (7) is added to a mixed solution of potassium dichromate (15 mmol) and sulfuric acid (10 mL, concentration of 3.5 mol / L), and an oxidation reaction is carried out under heating conditions (65° C.) for 3.5 hours; after the reaction is completed, the reaction mixture is first cooled to room temperature, and then a preliminary separation is performed by an extraction method. The reaction mixture is extracted three times with ethyl acetate (50 mL), the organic phases are combined, and insoluble impurities are removed by filtration to obtain the compound.

[0114] Test Example In this example, the compound of formula (I) obtained in the above Example 1 was used as an electrolyte additive, and was further prepared into an electrolyte and a lithium-ion battery.

[0115] The positive electrode active material of the lithium-ion battery used in this example is a ternary material (LiNi 0.6 Co 0.2 Mn 0.2 O 4), artificial graphite is selected as the negative electrode material, and the amount of electrolyte used is 2.3±0.5g / Ah. A lithium-ion battery assembled with a high-voltage lithium-ion battery electrolyte containing the compound represented by formula (I) is selected as an implementation test example, and a lithium-ion battery assembled with a conventional electrolyte not containing the compound represented by formula (I) and an electrolyte added with the compound represented by formula (II) is selected as a comparative test example.

[0116] In the glove box (H 2 The specific steps for preparing the electrolyte (O<5ppm) are as follows:

[0117] (1) dehydrating an anhydrous organic solvent molecular sieve under the protection of nitrogen or inert gas to obtain an anhydrous organic solvent;

[0118] (2) adding an appropriate amount of lithium salt to an anhydrous organic solvent, stirring and cooling to obtain a mixed solution;

[0119] (3) Add appropriate amount of additives to the mixed solution to obtain 2000 g of electrolyte, which is placed in a fluorination bottle.

[0120] The electrolyte is used to assemble a lithium-ion battery. The positive electrode material of the lithium-ion battery is a ternary material, the negative electrode material is artificial graphite, the designed capacity is 60Ah, and the injection amount is 2.3±0.5g / Ah.

[0121] Implementation of test case 1:

[0122] The non-aqueous organic solvent used was: ethylene carbonate: propylene carbonate: dimethyl carbonate: diethyl carbonate: ethyl methyl carbonate = 30:10:5:10:45; lithium salt: 0.8M lithium hexafluorophosphate (LiPF 6 ), the concentration is 0.4M lithium bis(fluorosulfonyl)imide (LiFSI). Additives: 0.5% TMSP, 0.3% LiBOB, 0.3% LiDFOB, 0.3% VC, 1% FEC, 0.5% PS, 1% DFEA, 0.5% FPN, 8% compound represented by formula (I).

[0123] Implementation of test case 2:

[0124] The non-aqueous organic solvent used was: ethylene carbonate: propylene carbonate: dimethyl carbonate: diethyl carbonate: ethyl methyl carbonate = 30:10:5:10:45; lithium salt: 0.8M lithium hexafluorophosphate (LiPF 6 ), the concentration is 0.4M lithium bis(fluorosulfonyl)imide (LiFSI). Additives: 0.5% TMSP, 0.3% LiBOB, 0.3% LiDFOB, 0.3% VC, 1% FEC, 0.5% PS, 1% DFEA, 0.5% FPN, 5% compound represented by formula (I).

[0125] Implementation of test case 3:

[0126] The non-aqueous organic solvent used was: ethylene carbonate: propylene carbonate: dimethyl carbonate: diethyl carbonate: ethyl methyl carbonate = 30:10:5:10:45; lithium salt: 0.8M lithium hexafluorophosphate (LiPF 6 ), the concentration is 0.4M lithium bis(fluorosulfonyl)imide (LiFSI). Additives: 0.5% TMSP, 0.3% LiBOB, 0.3% LiDFOB, 0.3% VC, 1% FEC, 0.5% PS, 1% DFEA, 0.5% FPN, 1% compound represented by formula (I).

[0127] Comparative test example 1:

[0128] The non-aqueous organic solvent used was: ethylene carbonate: propylene carbonate: dimethyl carbonate: diethyl carbonate: ethyl methyl carbonate = 30:10:5:10:45; lithium salt: lithium hexafluorophosphate (LiPF 6 ).

[0129] Comparative test example 2:

[0130] The non-aqueous organic solvent used was: ethylene carbonate: propylene carbonate: dimethyl carbonate: diethyl carbonate: ethyl methyl carbonate = 30:10:5:10:45; lithium salt: 0.8M lithium hexafluorophosphate (LiPF 6 ), with a concentration of 0.4 M lithium bis(fluorosulfonyl)imide (LiFSI).

[0131] Comparative test example 3:

[0132] The non-aqueous organic solvent used was: ethylene carbonate: propylene carbonate: dimethyl carbonate: diethyl carbonate: ethyl methyl carbonate = 30:10:5:10:45; lithium salt: 0.8M lithium hexafluorophosphate (LiPF 6 ), the concentration is 0.4M lithium bis(fluorosulfonyl)imide (LiFSI). Additives: 0.5% TMSP, 0.3% LiBOB, 0.3% LiDFOB, 0.3% VC, 1% FEC, 0.5% PS, 1% DFEA, 0.5% FPN.

[0133] Comparative test example 4:

[0134] The difference between this example and implementation test example 3 is that the compound represented by formula (I) is replaced by the compound represented by formula (II) (CAS registration number is 126144-69-2);

[0135] The formula (II):

[0136] The lithium-ion batteries assembled in the above comparative test examples and implementation test examples were subjected to a 1 / 3C discharge test at room temperature (25°C) and in the voltage range of 2.75-4.5V. The constant capacity, 2C charge capacity (%) = 2C charge capacity / 1C discharge capacity, 3C discharge capacity (%) = 3C discharge capacity / 1C discharge capacity, and the results are shown in Table 1.

[0137] Table 1 Short-term performance test results

[0138] Test samples Liquid retention / g Fixed capacity / Ah First efficiency 2C charging 3C discharge Comparative test example 1 140.6 60.49 72.9％ 33.4％ 33.3％ Comparative test example 2 140.9 60.32 78.3％ 63.0％ 69.2％ Comparative test example 3 140.6 60.48 88.6％ 94.4％ 96.5％ Comparative test example 4 140.5 60.45 88.5％ 94.5％ 96.5％ Implementation of test case 1 140.8 60.14 90.5％ 95.0％ 96.1％ Implementation of Test Example 2 140.1 60.02 91.7％ 94.4％ 96.0％ Implementation of Test Case 3 140.4 60.62 92.2％ 94.6％ 96.3％

[0139] The lithium-ion batteries assembled in the comparative test example and the implementation test example were discharged at 1C or 1 / 3C in the range of -30℃ to 55℃ to test the capacity, and the voltage range was 2.75 to 4.5V. The gas generation of the battery was observed, and the battery was disassembled after low-temperature discharge to observe the pole pieces. The results are shown in Tables 2 and 3.

[0140] Table 2 High and low temperature discharge performance test results 1

[0141] Test samples 55℃1C 45℃1C 10℃1C 0℃1C -10℃1C -10℃1 / 3C Comparative test example 1 55.2％ 55.2％ 25.2％ 25.2％ 15.2％ 15.2％ Comparative test example 2 78.5％ 78.5％ 68.5％ 68.5％ 58.5％ 58.5％ Comparative test example 3 94.1％ 94.1％ 84.1％ 84.1％ 74.1％ 74.1％ Comparative test example 4 94.5％ 94.5％ 84.5％ 84.5％ 74.5％ 74.5％ Implementation of test case 1 100.9％ 101.9％ 94.0％ 90.0％ 87.0％ 85.0％ Implementation of Test Example 2 101.8％ 102.8％ 95.5％ 91.5％ 88.5％ 86.5％ Implementation of Test Case 3 103.0％ 104.0％ 96.4％ 92.4％ 89.4％ 87.4％

[0142] Table 2 High and low temperature discharge performance test results II

[0143]

[0144]

[0145] The lithium-ion batteries assembled in the comparative test example and the implementation test example were subjected to a needle penetration test at 25° C. and 100% SOC. The results are shown in Table 4.

[0146] Table 4 Acupuncture test results

[0147] Test samples acupuncture Comparative test example 1 Fire Comparative test example 2 Fire Comparative test example 3 Fire Comparative test example 4 Fire Implementation of test case 1 No fire Implementation of Test Example 2 No fire Implementation of Test Case 3 No fire

[0148] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A compound, characterized in that The chemical structural formula of the compound is shown in formula (I); The formula (I):

2. A method for preparing the compound according to claim 1, characterized in that: The preparation method comprises the following steps: Dissolving decalin and bromine in a first solvent and performing a first reaction under light conditions to obtain a first product; dissolving the first product, ethyl p-toluenesulfonylcarbamate and a base in a second solvent to carry out a second reaction to obtain a second product; The second product is subjected to a third reaction in a potassium permanganate / sulfuric acid system, and after the third reaction, sodium hydroxide is added to carry out a fourth reaction to obtain a third product; dissolving the third product and sodium azide in a third solvent to carry out a fifth reaction to obtain a fourth product; dissolving the fourth product and lithium aluminum hydride in a fourth solvent to carry out a sixth reaction, and adding hydrochloric acid after the sixth reaction to carry out a seventh reaction to obtain a fifth product; dissolving the fifth product in a fifth solvent and adding an initiator to carry out an eighth reaction to obtain a sixth product; Adding the sixth product to a strong alkaline solution to carry out a ninth reaction to obtain a seventh product; The seventh product is added into a potassium dichromate / sulfuric acid system to carry out a tenth reaction to obtain the compound.

3. The method for preparing the compound according to claim 2, characterized in that: The working condition parameters of the first reaction include: the molar ratio of the decalin to the bromine is 1:(1.0-1.3), the temperature is 24-28° C., the time is 2-3 hours, the first solvent includes carbon tetrachloride, the illumination is a mercury lamp, and the illumination parameters of the mercury lamp include: the illumination power is 100-200W, and the illumination distance is 10-20cm; The working condition parameters of the second reaction include: the molar ratio of the first product, the ethyl p-toluenesulfonylcarbamate and the base is 1:(1.0-1.3):(1.2-2.0), the base includes potassium carbonate, the second solvent includes dimethylformamide, the temperature is 60-70° C., and the time is 4-6 hours; The working condition parameters of the third reaction include: the molar ratio of the second product, the potassium permanganate, and the sulfuric acid is 1:(1.2-1.8):(2-3), the temperature is 24-28° C., and the time is 3-4 hours; The working condition parameters of the fourth reaction include: the molar amount of the sodium hydroxide added is 1.5 to 2.5 times the molar amount of the second product, the temperature is 80 to 90° C., and the time is 2 to 3 hours; The working condition parameters of the fifth reaction include: the molar ratio of the third product to the sodium azide is 1:(1.0-1.5), the temperature is 80-90° C., the time is 4-6 hours, and the third solvent includes dimethyl sulfoxide; The working condition parameters of the sixth reaction include: the molar ratio of the fourth product to the lithium aluminum hydride is (1.0-1.2):(1.0-1.2), the fourth solvent includes anhydrous ether, the temperature is -15--8°C, and the time is 3-4 hours; The working condition parameters of the seventh reaction include: the molar amount of the hydrochloric acid is 1 to 2 times the molar amount of the fourth product, the temperature is 50 to 60° C., and the time is 2 to 3 hours; The working condition parameters of the eighth reaction include: a temperature of 40 to 50° C., a time of 4 to 6 hours, the initiator is composed of N-bromosuccinimide and benzoyl peroxide, the molar ratio of the N-bromosuccinimide, the benzoyl peroxide and the fifth product is (10 to 20):1:(8 to 12), and the fifth solvent includes dichloromethane; The working condition parameters of the ninth reaction include: the molar ratio of the sixth product to the strong base is 1:(1.5-3), the strong base includes sodium hydroxide, the temperature is 80-90° C., and the time is 6-8 hours; The working condition parameters of the tenth reaction include: the molar ratio of the seventh product, the potassium dichromate and the sulfuric acid is 1:(1.2-2.0):(3-4), the temperature is 60-70°C, and the time is 3-4 hours.

4. The method for preparing the compound according to claim 2, characterized in that: The working condition parameters of the first reaction include: the molar ratio of the decalin to the bromine is 1:1.2, the temperature is 25° C., the time is 2 to 3 hours, the first solvent includes carbon tetrachloride, the illumination is a mercury lamp, and the illumination parameters of the mercury lamp include: the illumination power is 150W, and the illumination distance is 15 cm; The working condition parameters of the second reaction include: the molar ratio of the first product, the ethyl p-toluenesulfonylcarbamate and the base is 1:1.2:1.5, the base includes potassium carbonate, the second solvent includes dimethylformamide, the temperature is 60-70° C., and the time is 4-6 hours; The working condition parameters of the third reaction include: the molar ratio of the second product, the potassium permanganate, and the sulfuric acid is 1:1.5:(2-3), the temperature is 24-28° C., and the time is 3-4 hours; The working condition parameters of the fourth reaction include: the molar amount of the sodium hydroxide added is twice the molar amount of the second product, the temperature is 80-90° C., and the time is 2-3 hours; The working condition parameters of the fifth reaction include: the molar ratio of the third product to the sodium azide is 1:1.2, the temperature is 80-90° C., the time is 4-6 hours, and the third solvent includes dimethyl sulfoxide; The working condition parameters of the sixth reaction include: the molar ratio of the fourth product to the lithium aluminum hydride is 1:1, the fourth solvent includes anhydrous ether, the temperature is -10°C, and the time is 3 to 4 hours; The working condition parameters of the seventh reaction include: the molar amount of the hydrochloric acid is 1.5 times the molar amount of the fourth product, the temperature is 50-60° C., and the time is 2-3 hours; The working condition parameters of the eighth reaction include: a temperature of 40 to 50° C., a time of 4 to 6 hours, the initiator is composed of N-bromosuccinimide and benzoyl peroxide, the molar ratio of the N-bromosuccinimide, the benzoyl peroxide and the fifth product is 12:1:10, and the fifth solvent includes dichloromethane; The working condition parameters of the ninth reaction include: the molar ratio of the sixth product to the strong base is 1:2, the strong base includes sodium hydroxide, the temperature is 80-90° C., and the time is 6-8 hours; The working condition parameters of the tenth reaction include: the molar ratio of the seventh product, the potassium dichromate and the sulfuric acid is 1:1.5:(3-4), the temperature is 60-70°C, and the time is 3-4 hours.

5. Use of the compound according to any one of claims 1 to 4 in the preparation of lithium ion battery electrolyte additives and electrolytes.

6. A lithium ion battery electrolyte addition, characterized in that: The lithium ion battery electrolyte is added with the compound according to any one of claims 1 to 4.

7. An electrolyte, characterized in that: The electrolyte comprises the compound according to any one of claims 1 to 4.

8. The electrolyte according to claim 7, characterized in that The electrolyte comprises a lithium salt, an anhydrous organic solvent, the compound according to any one of claims 1 to 4, and a second additive; The molar concentration of the lithium salt in the electrolyte is 0.8M-1.4M; In terms of weight percentage, the amount of the anhydrous organic solvent accounts for 60-80% of the total weight of the electrolyte; In terms of weight percentage, the amount of the compound is 0.1 to 10% of the total weight of the electrolyte; In terms of weight percentage, the amount of the second additive is 0.1 to 20% of the total weight of the electrolyte; The second additive includes at least one of tris(trimethylsilyl)borate, lithium bis(oxalatoborate), lithium bis(fluorooxalatoborate), tetramethyl borate, trimethyl borate, trimethylcyclotriboroxane, tris(2,2,2-trifluoroethyl)phosphite, triphenylphosphite, tris(trimethylsilyl)phosphite, trimethyl phosphite, vinylene carbonate, fluoroethylene carbonate, 1,3-propane sultone, succinic anhydride, 5-hydroxy-1H-indazole, phenyl maleic anhydride, hexabutylcyclohexane-1,2,3,4,5,6-hexylamine, acetylenic silylpyridine compound, triphenyl phosphite, bismaleimide, triallyl phosphate, dimethanesulfonyl methane, trifluoromethylphenyl sulfide, perfluoroalkyl-substituted ethylene carbonate, ethyl 2,2-difluoroacetate, and pentafluoroethoxycyclotriphosphazene.

9. The electrolyte according to claim 8, characterized in that In terms of weight percentage, the amount of the compound is 0.1-5% of the total weight of the electrolyte, the lithium salt includes at least one of lithium hexafluorophosphate and lithium bis(fluorosulfonyl)imide, and the anhydrous organic solvent includes at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propionate, ethyl butyrate, γ-butyrolactone, dimethoxyethane, tetrahydrofuran, cyclopentane, fluoromethyl-substituted ethylene carbonate, perfluorobutyl-substituted ethylene carbonate, perfluorohexyl-substituted ethylene carbonate, perfluorooctyl-substituted ethylene carbonate, methyl acetate and ethyl propionate.

10. The electrolyte according to claim 8, characterized in that In terms of weight percentage, the amount of the compound is 0.1-2% of the total weight of the electrolyte; the electrolyte is a high-voltage lithium-ion battery electrolyte, and the working voltage of the high-voltage lithium-ion battery electrolyte is 2.75-4.5V.

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