Ethylene sulfate compound, synthesis method and application of ethylene sulfate compound in secondary battery

Abstract

The invention provides an ethylene sulfate compound, a synthesis method and application of the ethylene sulfate compound in a secondary battery, and relates to the technical field of material synthesis. The ethylene sulfate compound has a structure as shown in a formula I in the specification. The synthesis method of the ethylene sulfate compound comprises the following steps: reacting diacetone-D-mannitol, an amide acetal compound and a first organic solvent at room temperature to obtain an intermediate A, adding methyl iodide and a second organic solvent into the intermediate A, and carrying out reflux reaction to obtain an intermediate product A; and dissolving the intermediate product A in a third organic solvent, adding an acid compound, carrying out a deprotection reaction at room temperature to obtain an intermediate B, adding a basic catalyst and a fourth organic solvent into the intermediate B, dropwise adding a sulfonylation reagent, and carrying out a sulfonylation reaction at room temperature to obtain the ethylene sulfate compound. The ethylene sulfate compound disclosed by the invention is novel in structure, contains double bonds, sulfur elements and oxygen elements, has a good application prospect, and can be applied to secondary batteries.

Description

Technical Field

[0001] The invention relates to the technical field of material synthesis, and in particular to a vinyl sulfate compound, a synthesis method and application thereof in a secondary battery. Background Art

[0002] As the performance requirements of lithium-ion batteries in various application fields continue to rise, high energy density, long cycle life, high rate performance, wide temperature range and high safety have become the focus of lithium-ion battery research. In lithium-ion batteries, electrolytes are an indispensable component as carriers of ion transmission in lithium-ion batteries. Therefore, the development of greener and more efficient electrolytes is of great significance for improving the electrochemical performance of lithium-ion batteries. Among the many strategies to improve the performance of electrolytes, adding different types of additives to electrolytes is considered to be an effective and economical method. Film-forming additives play an important role in electrolyte additives. Film-forming additives can react chemically on the electrode surface at the initial stage of battery charging and discharging to form a uniform, dense and stable solid electrolyte interface film (SEI film). The SEI film can effectively prevent further reaction between the electrolyte and the electrode material, inhibit the dissolution of the electrode material and the decomposition of the electrolyte, thereby effectively improving the electrochemical performance of the battery. Organic compounds, as the main component of film-forming additives, are of various types and abundant in quantity. Research in this field has a long history and has achieved many important results.

[0003] However, although a large number of organic compound additives have been developed, there are still many problems that need to be solved. On the one hand, the effects of a considerable number of organic compound additives in practical applications have not met expectations and cannot effectively meet the increasingly stringent battery performance requirements; on the other hand, some additives with excellent performance, such as fluorine-containing additives, are greatly restricted in practical applications due to their potential harm to the environment and toxicity issues, and may even be forced to abandon their use. Therefore, it is urgent to continue to develop additives that have excellent performance and are environmentally friendly. Summary of the invention

[0004] Based on the above problems, the object of the present invention is to provide a vinyl sulfate compound, a synthesis method and its application in a secondary battery. The synthesis method of the vinyl sulfate compound of the present invention is simple, the reaction process is mild, the operation difficulty is low, the purity and yield of the obtained product are high, and the structure is novel. The structure contains double bonds, sulfur elements and oxygen elements, does not contain halogens, is relatively friendly to the environment, has good application prospects, and can be applied to secondary batteries.

[0005] To achieve the above object, the first aspect of the present invention provides a vinyl sulfate compound having a structure shown in Formula 1: .

[0006] Compared with the prior art, the vinyl sulfate compound of the present invention has a novel structure, contains double bonds, sulfur elements and oxygen elements, does not contain halogens, and is relatively environmentally friendly. The presence of double bonds enables the structure to have good reactivity, and further functional group modifications can be performed on it. These functional group modifications can further improve the performance under specific environments, and can also enhance its compatibility and cross-linking ability with other materials or compounds to meet the requirements of different application fields. Therefore, it has good application prospects and can be applied to secondary batteries.

[0007] The second aspect of the present invention provides a method for synthesizing vinyl sulfate compounds, comprising the steps of: (1) reacting diacetone-D-mannitol, an amide acetal compound, and a first organic solvent at room temperature, performing a first reduced pressure distillation to obtain an intermediate A, and then adding iodomethane and a second organic solvent to the intermediate A for a reflux reaction to obtain an intermediate product A; (2) The intermediate product A is dissolved in a third organic solvent, an acid compound is added, and a deprotection reaction is carried out at room temperature, followed by a second reduced pressure distillation to obtain an intermediate product B, an alkaline catalyst and a fourth organic solvent are added to the intermediate product B, a sulfonylating agent is added dropwise, and a sulfonylating reaction is carried out at room temperature, and a vinyl sulfate compound is obtained after post-treatment.

[0008] Compared with the prior art, the present invention firstly utilizes diacetone-D-mannitol to react with an amide acetal compound, and by selecting mannitol with protection at both ends, competitive reactions can be effectively reduced, and the occurrence of side reactions can be reduced. The amide acetal compound has two alkoxy active groups as an alkylating agent, and the alkoxy group can react with the hydroxyl group in diacetone-D-mannitol to obtain an intermediate A having an oxygen-containing heterocycle and a tertiary amine structure. The tertiary amine structure in the intermediate A is attacked by iodomethane to form a quaternary ammonium salt structure, which has an unstable structure. An E2 elimination reaction can occur under the condition of no catalyst and only heating to obtain an intermediate product A having a double bond structure. In the subsequent deprotection and sulfonylation steps of the intermediate product A, simple, easy-to-obtain, cheap and mild reaction reagents are used, the reaction conditions are mild, the side reactions are few, and the by-products, reaction solvents and the like in the synthesis process can be effectively removed by reduced pressure distillation, so the yield and purity of the reaction product are high.

[0009] As a preferred technical solution, the molar ratio of diacetone-D-mannitol, amide acetal compound and methyl iodide in the present invention is 1:2.1~3:2~2.5.

[0010] As a preferred technical solution, the temperature of the reflux reaction of the present invention is 60°C to 120°C, and the time of the reflux reaction is 4h to 24h.

[0011] As a preferred technical solution, the molar ratio of the intermediate product A, the acid compound, the alkaline catalyst and the sulfonylating agent of the present invention is 1:2~5:2~2.5:2.5~3.

[0012] As a preferred technical solution, the sulfonylation reaction time of the present invention is 1h~24h.

[0013] As a preferred technical solution, the sulfonylating agent of the present invention is selected from sulfonyl fluoride or sulfonyl chloride.

[0014] As a preferred technical solution, the dripping temperature of the sulfonylation reagent of the present invention is -15°C to 10°C, and the dripping rate is 1 g / h to 120 g / h.

[0015] As a preferred technical solution, the amide acetal compound of the present invention is selected from at least one of N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide diisopropyl acetal, N,N-diethylformamide dimethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide di-tert-butyl acetal, N,N-dimethylformamide dineopentyl acetal, N,N-dimethylformamide dibenzyl acetal and N,N-dimethylformamide dibutyl acetal.

[0016] As a preferred technical solution, the acid compound of the present invention is selected from at least one of hydrochloric acid, Amberlyst 15 dry, trifluoroacetic acid, Amberlyst 15 wet, acetic acid, sulfuric acid, and acetic anhydride.

[0017] As a preferred technical solution, the alkaline catalyst of the present invention is selected from at least one of triethylamine, pyridine, DMAP, 2,6-lutidine, 1-pyridine-4-piperidine, cesium carbonate, sodium hydroxide, sodium methoxide, potassium tert-butoxide, potassium carbonate, zinc acetate, DBU, DIPEA, tetramethylethylenediamine, and N-methylmorpholine.

[0018] As a preferred technical solution, the first organic solvent, the second organic solvent, the third organic solvent and the fourth organic solvent of the present invention are each independently selected from at least one of nitrile solvents, halogenated hydrocarbon solvents, ketone solvents, ether solvents, ester solvents, alcohol solvents, aromatic hydrocarbon solvents, amide solvents and sulfone solvents.

[0019] As a preferred technical solution, the temperatures of the first vacuum distillation and the second vacuum distillation of the present invention are independently 40°C to 100°C.

[0020] As a preferred technical solution, the pressures of the first vacuum distillation and the second vacuum distillation of the present invention are independently 5 mmHg to 1000 mmHg.

[0021] As a preferred technical solution, the post-treatment of the present invention includes washing, concentration, recrystallization and drying.

[0022] The third aspect of the present invention provides the use of the aforementioned vinyl sulfate compound or the vinyl sulfate compound obtained by the aforementioned method for synthesizing the vinyl sulfate compound in a secondary battery. The vinyl sulfate compound of the present invention can form a SEI film at the negative electrode interface of the battery in the electrolyte, and the divinyl sulfate structure contained therein can increase the content of sulfur and oxygen elements in the SEI film, thereby effectively improving the electrochemical performance of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the hydrogen spectrum of the vinyl sulfate compound prepared in Example 1 of the present invention; Figure 2 is the hydrogen spectrum of the intermediate product A obtained in Example 1 of the present invention; Figure 3 is the hydrogen spectrum of the intermediate B prepared in Example 1 of the present invention; Figure 4 is a liquid chromatogram of the vinyl sulfate compound prepared in Example 1 of the present invention; Figure 5 is a liquid chromatogram of the vinyl sulfate compound prepared in Example 2 of the present invention; Figure 6 is a liquid chromatogram of the vinyl sulfate compound prepared in Example 3 of the present invention; Figure 7 This is a liquid chromatogram of the vinyl sulfate compound prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0024] The vinyl sulfate compound of the present invention contains a double bond, sulfur and oxygen in its structure and has good application prospects, in particular, it can be used as an electrolyte additive in secondary batteries to improve their electrochemical performance.

[0025] The vinyl sulfate compound of the present invention has a structure shown in Formula 1: .

[0026] The method for synthesizing vinyl sulfate compounds of the present invention comprises the steps of: (1) reacting diacetone-D-mannitol, an amide acetal compound, and a first organic solvent at room temperature, performing a first reduced pressure distillation to obtain an intermediate A, and then adding iodomethane and a second organic solvent to the intermediate A for a reflux reaction to obtain an intermediate product A; (2) The intermediate product A is dissolved in a third organic solvent, an acid compound is added, and a deprotection reaction is carried out at room temperature, followed by a second reduced pressure distillation to obtain an intermediate product B, an alkaline catalyst and a fourth organic solvent are added to the intermediate product B, a sulfonylating agent is added dropwise, and a sulfonylating reaction is carried out at room temperature, and a vinyl sulfate compound is obtained after post-treatment.

[0027] Specifically, the reaction route of step (1) can be shown as reaction formula 1:

[0028] Specifically, the reaction route of step (2) can be shown in Reaction Scheme 2:

[0029] Further, the molar ratio of diacetone-D-mannitol, amide acetal compound and methyl iodide is 1:2.1~3:2~2.5. As an example, the molar ratio of diacetone-D-mannitol, amide acetal compound and methyl iodide can be, but not limited to, 1:2.1:2, 1:2.1:2.1, 1:2.1:2.2, 1:2.1:2.3, 1:2.1:2.4, 1:2.1:2.5, 1:2.2:2, 1:2.2:2.1, 1:2.2:2.2, 1:2.2:2.3, 1 :2.2:2.4, 1:2.2:2.5, 1:2.5:2, 1:2.5:2.1, 1:2.5:2.2, 1:2.5:2.3, 1:2.5:2.4, 1:2.5:2.5, 1:2.8:2, 1:2.8:2.1, 1:2.8:2.2, 1:2.8:2.3, 1:2.8:2.4, 1:2.8:2.5, 1:3:2, 1:3:2.1, 1:3:2.2, 1:3:2.3, 1:3:2.4, 1:3:2.5.

[0030] Furthermore, the reaction time of diacetone-D-mannitol, amide acetal compound and the first organic solvent at room temperature is 18 h to 36 h. As an example, the reaction time can be but is not limited to 18 h, 20 h, 22 h, 24 h, 28 h, 30 h, and 36 h.

[0031] Further, the temperature of the reflux reaction is 60°C to 120°C. As an example, the temperature of the reflux reaction may be, but is not limited to, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C. Preferably, the temperature of the reflux reaction is 80°C to 120°C. The time of the reflux reaction is 4h to 24h. As an example, the time of the reflux reaction may be, but is not limited to, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h.

[0032] Further, the temperature of the first vacuum distillation is 40°C to 100°C. As an example, the temperature of the first vacuum distillation can be, but not limited to, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, and 100°C. The pressure of the first vacuum distillation is 5mmHg to 1000mmHg. As an example, the pressure of the first vacuum distillation can be, but not limited to, 5mmHg, 50mmHg, 100mmHg, 200mmHg, 300mmHg, 400mmHg, 500mmHg, 600mmHg, 700mmHg, 800mmHg, 900mmHg, and 1000mmHg.

[0033] Furthermore, the amide acetal compound can be selected from at least one of N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide diisopropyl acetal, N,N-diethylformamide dimethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide di-tert-butyl acetal, N,N-dimethylformamide dineopentyl acetal, N,N-dimethylformamide dibenzyl acetal and N,N-dimethylformamide dibutyl acetal.

[0034] Further, the molar ratio of the intermediate product A, the acid compound, the alkaline catalyst and the sulfonylating agent is 1:2~5:2~2.5:2.5~3. As an example, the molar ratio of the intermediate product A, the alkaline catalyst and the sulfonylating agent can be, but is not limited to, 1:2:2:2.5, 1:2:2:2.6, 1:2:2:2.7, 1:2:2:2.8, 1:2:2:2.9, 1:2:2:3, 1:2:2.2:2.5, 1:2:2:2.6 :2:2.2:2.6, 1:2:2.2:2.7, 1:2:2.2:2.8, 1:2:2.2:2.9, 1:2:2.2:3, 1:2:2.4:2.5, 1:2:2.4:2.6, 1:2:2.4:2.7, 1:2:2.4:2.8, 1:2:2.4:2.9, 1:2:2.4:3, 1:2:2.5:2.5, 1:2:2.5:2.6, 1:2: 2.5:2.7, 1:2:2.5:2.8, 1:2:2.5:2.9, 1:2:2.5:3, 1:3:2:2.5, 1:3:2:2.6, 1:3:2:2.7, 1:3:2:2.8, 1:3:2:2.9, 1:2:2:3, 1:3:2.2:2.5, 1:3:2.2:2.6, 1:3:2.2:2.7, 1:3:2.2:2.8, 1:3:2.2 :2.9, 1:3:2.2:3, 1:3:2.4:2.5, 1:3:2.4:2.6, 1:5:2.4:2.7, 1:5:2.4:2.8, 1:5:2.4:2.9, 1:5:2.4:3, 1:5:2.5:2.5, 1:5:2.5:2.6, 1:5:2.5:2.7, 1:5:2.5:2.8, 1:5:2.5:2.9, 1:5:2.5:3.

[0035] Furthermore, the deprotection reaction time is 4 h to 12 h. As an example, the deprotection reaction time can be but is not limited to 4 h, 6 h, 8 h, 10 h, and 12 h.

[0036] Furthermore, the time of the sulfonylation reaction is 1 h to 24 h. As an example, the time of the sulfonylation reaction can be, but is not limited to, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, and 24 h.

[0037] Further, the sulfonylating agent may be selected from sulfonyl fluoride or sulfonyl chloride.

[0038] Further, the dropping temperature of the sulfonylating agent is -15°C to 10°C. As an example, the dropping temperature of the sulfonylating agent may be, but is not limited to, -15°C, -12°C, -10°C, -8°C, -6°C, -4°C, -2°C, 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, 10°C. The dropping rate of the sulfonylating agent is 1g / h to 120g / h. As an example, the dropping rate of the sulfonylating agent may be, but is not limited to, 1g / h, 10g / h, 20g / h, 30g / h, 40g / h, 50g / h, 60g / h, 70g / h, 80g / h, 90g / h, 100g / h, 110g / h, 120g / h.

[0039] Further, the temperature of the second vacuum distillation is 40°C to 100°C. As an example, the temperature of the second vacuum distillation can be, but is not limited to, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, and 100°C. The pressure of the second vacuum distillation is 5mmHg to 1000mmHg. As an example, the pressure of the second vacuum distillation can be, but is not limited to, 5mmHg, 50mmHg, 100mmHg, 200mmHg, 300mmHg, 400mmHg, 500mmHg, 600mmHg, 700mmHg, 800mmHg, 900mmHg, and 1000mmHg.

[0040] Furthermore, the acid compound can be selected from at least one of hydrochloric acid, Amberlyst 15 dry, trifluoroacetic acid, Amberlyst 15 wet, acetic acid, sulfuric acid, and acetic anhydride.

[0041] Furthermore, the alkaline catalyst is selected from at least one of triethylamine, pyridine, DMAP (4-dimethylaminopyridine), 2,6-lutidine, 1-pyridine-4-piperidine, cesium carbonate, sodium hydroxide, sodium methoxide, potassium tert-butoxide, potassium carbonate, zinc acetate, DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), DIPEA (N,N-diisopropylethylamine), tetramethylethylenediamine, and N-methylmorpholine.

[0042] Further, the first organic solvent, the second organic solvent, the third organic solvent and the fourth organic solvent are each independently selected from at least one of nitrile solvents, halogenated hydrocarbon solvents, ketone solvents, ether solvents, ester solvents, alcohol solvents, aromatic hydrocarbon solvents, amide solvents and sulfone solvents. Specifically, the nitrile solvent can be selected from acetonitrile, the halogenated hydrocarbon solvent can be selected from dichloromethane or dichloroethane, the ketone solvent can be selected from acetone, the ether solvent can be selected from tetrahydrofuran, the ester solvent can be selected from ethyl acetate or methyl acetate, the alcohol solvent can be selected from methanol or ethanol, the aromatic hydrocarbon solvent can be selected from toluene, the amide solvent can be selected from DMF (N, N-dimethylformamide), DMA (N, N-dimethylacetamide) or N-methylpyrrolidone, and the sulfone solvent can be selected from DMSO (dimethyl sulfoxide) or cyclopentane.

[0043] Furthermore, the post-treatment may include washing, concentrating, recrystallizing and drying. Specifically, the post-treatment includes adding water to the reaction solution after the sulfonylation reaction for extraction and washing, then concentrating the organic phase and adding a solvent for recrystallization, and finally drying the obtained solid.

[0044] Wherein, the concentration can be specifically reduced pressure distillation, the temperature of reduced pressure distillation can be but not limited to 40°C, and the pressure of reduced pressure distillation can be but not limited to 80 mmHg. The solvent used for recrystallization can be at least one of hydrocarbon solvents, halogenated hydrocarbon solvents, alcohol solvents, ether solvents, and carbonate solvents. Wherein, the hydrocarbon solvent can be but not limited to petroleum ether, n-hexane, n-heptane, n-octane or toluene, the halogenated hydrocarbon solvent can be but not limited to dichloromethane or dichloroethane, the alcohol solvent can be but not limited to methanol or ethanol, the ether solvent can be but not limited to tetrahydrofuran, ether, dimethyl ether, methyl ethyl ether or anisole, and the carbonate solvent can be but not limited to dimethyl carbonate, ethyl methyl carbonate or diethyl carbonate. Drying can be vacuum drying, and the drying temperature is 40°C to 70°C. As an example, the drying temperature can be but not limited to 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C.

[0045] Furthermore, the temperatures of the first vacuum distillation and the second vacuum distillation may be the same or different, and the pressures of the first vacuum distillation and the second vacuum distillation may be the same or different.

[0046] Furthermore, the synthesis reaction of the vinyl sulfate compound of the present invention can be specifically carried out in a three-mouth ground-mouth reactor. The ground-mouth design enables the reactor to maintain a good sealing state under working conditions, ensuring the accuracy and safety of the experiment. The three-mouth design facilitates the installation of a thermometer in the reaction system to achieve strict control of the temperature during the reaction. Furthermore, a jacket can be provided on the periphery of the three-mouth ground-mouth reactor to achieve more accurate control of the temperature inside the reactor.

[0047] In order to better illustrate the purpose, technical scheme and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of the present invention and should not be used as a limitation of the present invention.

[0048] Part I: Synthesis of Vinyl Sulfate Ester Compounds Example 1 This embodiment provides a method for synthesizing vinyl sulfate compounds, comprising the steps of: (1) 131.2 g of diacetone-D-mannitol, 143.0 g of N,N-dimethylformamide dimethyl acetal, and 600.0 g of dichloromethane were placed in a 2000 mL jacketed ground-mouth three-mouth reactor and stirred at room temperature for 18 h. Then, dichloromethane and unreacted N,N-dimethylformamide dimethyl acetal were removed by reduced pressure distillation at 50°C and 60 mmHg to obtain intermediate A. 170.3 g of iodomethane and 600.0 g of toluene were added to intermediate A, and the temperature was raised to 110°C and refluxed for 2 h. After washing with water and distillation under reduced pressure, 110.0 g of intermediate product A was obtained. The yield was 96.4%. The hydrogen spectrum was 1 H NMR (500 MHz, DMSO- d 6 ) δ 5.74 (dd, J = 3.9,2.0 Hz, 2H), 4.51-4.47 (m, 2H), 4.04 (dd, J = 8.1, 6.3 Hz, 2H), 3.48 (t, J = 10.0Hz, 2H), 1.33 (s, 6H), 1.29 (s, 6H), hydrogen spectrum as shown Figure 2 shown.

[0049] (2) 110.0 g of intermediate product A was dissolved in 550.0 g of methanol, 200.0 g of Amberlyst15 dry catalyst was added and stirred at room temperature for 4 h. After filtering to remove the Amberlyst15 dry catalyst, the by-products were removed by vacuum distillation at 40°C and 80 mmHg to obtain intermediate product B. Hydrogen spectrum: 1 H NMR (500 MHz, Methanol- d 4 ) δ 5.77 (dd, J = 3.2,1.5 Hz, 2H), 4.12 (m, 2H), 3.48 (m, 4H), hydrogen spectrum as Figure 3As shown. Add 79.1g pyridine and 500.0g dichloromethane to the intermediate B, lower the system temperature to -10°C, and then use a constant pressure dropping funnel to drop 168.7g sulfonyl chloride at 80g / h. After the dropwise addition is completed, gradually raise the temperature to room temperature and react for 4h. After the reaction is completed, add water for washing, and then remove part of the solvent by reduced pressure distillation at 40°C and 80mmHg. Use n-hexane for recrystallization, and the obtained solid is vacuum dried at 55°C for 4h to obtain 113.2g of vinyl sulfate compounds shown in formula 1, with a yield of 86.3%. Hydrogen spectrum: 1 H NMR (400 MHz, DMSO- d 6 ) δ 6.21 (d, J = 6.6 Hz, 2H), 5.22-5.18 (m, 2H), 4.43 (d, J = 4.3 Hz, 2H),4.39 (d, J = 4.4 Hz, 2H), the hydrogen spectrum is as follows Figure 1 As shown in the liquid chromatogram Figure 4 As shown, the purity is 99.51%, proving that vinyl sulfate compounds have been synthesized.

[0050] Example 2 This embodiment provides a method for synthesizing vinyl sulfate compounds, comprising the steps of: (1) 131.2 g of diacetone-D-mannitol, 262.9 g of N,N-dimethylformamide diisopropyl acetal and 650.0 g of dimethyl carbonate were placed in a 2000 mL jacketed ground-mouth three-necked reactor and stirred for reaction at room temperature for 22 h. Dimethyl carbonate and unreacted N,N-dimethylformamide diisopropyl acetal were then removed by reduced pressure distillation at 45 °C and 100 mmHg to obtain intermediate A. 149.0 g of iodomethane and 650.0 g of acetonitrile were added to intermediate A, and the temperature was raised to 85 °C and refluxed for reaction for 6 h. After washing with water and distillation under reduced pressure, 109.0 g of intermediate product A was obtained with a yield of 95.5%. (2) 100.0 g of intermediate product A was dissolved in 500.0 g of tetrahydrofuran, 124.9 g of trifluoroacetic acid was added and stirred at room temperature for 8 h, then the by-products were removed by vacuum distillation at 50 ° C and 80 mmHg to obtain intermediate B, 101.9 g of triethylamine and 500.0 g of dichloroethane were added to intermediate B, the system temperature was lowered to -10 ° C, and 147.8 g of sulfonyl chloride was added dropwise at 50 g / h using a constant pressure dropping funnel. After the addition was completed, the temperature was gradually raised to room temperature and reacted for 6 h. After the reaction was completed, water was added for washing, and then part of the solvent was removed by vacuum distillation at 40 ° C and 80 mmHg. Ether was used for recrystallization, and the obtained solid was vacuum dried at 55 ° C for 4 h to obtain 102.4 g of the vinyl sulfate compound represented by formula 1, with a yield of 85.9%. The liquid chromatogram is shown in the figure below. Figure 5 As shown, the purity is 99.49%, proving that vinyl sulfate compounds have been synthesized.

[0051] Example 3 This embodiment provides a method for synthesizing vinyl sulfate compounds, comprising the steps of: (1) 131.2 g of diacetone-D-mannitol, 305.0 g of N,N-dimethylformamide dibutyl acetal and 500 g of acetonitrile were placed in a 2000 mL jacketed ground-mouth three-mouth reactor and stirred for reaction at room temperature for 22 h. Acetonitrile and unreacted N,N-dimethylformamide dibutyl acetal were then removed by reduced pressure distillation at 40°C and 80 mmHg to obtain intermediate A. 177.4 g of iodomethane and 650.0 g of 1,4-dioxane were added to intermediate A, and the temperature was raised to 110°C for reflux reaction for 2 h. After washing with water and distillation under reduced pressure, 108.2 g of intermediate product A was obtained with a yield of 94.8%. (2) Dissolve 100.0g of intermediate product A in 500.0g of acetone, add 100.0g of acetic anhydride and stir at room temperature for 6h, then remove by-products by vacuum distillation at 40℃ and 80mmHg to obtain intermediate B, add 123.6g of DMAP and 500.0g of dichloromethane to intermediate B, lower the system temperature to -10℃, and use a constant pressure dropping funnel to drop 102.0g of sulfonyl fluoride at 100g / h. After the addition is complete, gradually raise the temperature to room temperature and react for 4h. After the reaction is complete, add water for washing, then remove part of the solvent by vacuum distillation at 40℃ and 80mmHg, use n-octane for recrystallization, and vacuum dry the obtained solid at 55℃ for 4h to obtain 99.3g of vinyl sulfate compound represented by formula 1, with a yield of 83.3%. The liquid chromatogram is shown in Figure 6 As shown, the purity is 99.63%, proving that vinyl sulfate compounds have been synthesized.

[0052] Example 4 This embodiment provides a method for synthesizing vinyl sulfate compounds, comprising the steps of: (1) 131.2 g of diacetone-D-mannitol, 339.2 g of N,N-dimethylformamide dibenzyl acetal and 650.0 g of DMF were placed in a 2000 mL jacketed ground-mouth three-mouth reactor and stirred for reaction at room temperature for 18 h. DMF and unreacted N,N-dimethylformamide dibenzyl acetal were removed by reduced pressure distillation at 75 °C and 200 mmHg to obtain intermediate A. 177.4 g of iodomethane and 650.0 g of toluene were added to intermediate A, and the temperature was raised to 110 °C and refluxed for reaction for 2 h. After washing with water and distillation under reduced pressure, 106.0 g of intermediate product A was obtained with a yield of 92.9%. (2) Dissolve 100.0g of intermediate product A in 500.0g of methanol, add 73.0g of hydrochloric acid and stir at room temperature for 4h, then remove by-products by vacuum distillation at 50℃ and 80mmHg to obtain intermediate B, add 147.4g of DBU and 500.0g of DMSO to intermediate B, lower the system temperature to -10℃ and use a constant pressure dropping funnel to drop 178.2g of sulfonyl chloride at 65g / h, gradually raise the temperature to room temperature after the addition is complete and react for 4h, add water for washing after the reaction is complete, then remove part of the solvent by vacuum distillation at 40℃ and 80mmHg, use n-heptane for recrystallization, and vacuum dry the obtained solid at 55℃ for 4h to obtain 98.6g of vinyl sulfate compound represented by formula 1, with a yield of 82.7%. The liquid chromatogram is shown in Figure 7 As shown, the purity is 99.56%, proving that vinyl sulfate compounds have been synthesized.

[0053] Part II: Application of vinyl sulfate compounds in secondary batteries 1 g of the vinyl sulfate compound prepared in Examples 1 to 4 and 87 g of a non-aqueous organic solvent (propylene carbonate PC and diethyl carbonate DEC in a mass ratio of 2:1) were respectively mixed evenly, and then 12 g of lithium hexafluorophosphate LiPF6 was added and mixed evenly to prepare non-aqueous electrolytes 1# to 4#.

[0054] 1 g of 1,3-propylene sultone (PES) and 87 g of a non-aqueous organic solvent (propylene carbonate PC and diethyl carbonate DEC in a mass ratio of 2:1) were mixed evenly, and then 12 g of lithium hexafluorophosphate LiPF6 was added and mixed evenly to prepare a non-aqueous electrolyte 5#.

[0055] 1 g of vinyl sulfate (DTD) and 87 g of non-aqueous organic solvent (propylene carbonate PC and diethyl carbonate DEC in a mass ratio of 2:1) were mixed evenly, and then 12 g of lithium hexafluorophosphate LiPF6 was added and mixed evenly to prepare non-aqueous electrolyte 6#.

[0056] 88g of non-aqueous organic solvent (propylene carbonate PC and diethyl carbonate DEC in a mass ratio of 2:1) and 12g of lithium hexafluorophosphate LiPF6 were uniformly mixed to prepare non-aqueous electrolyte 7#.

[0057] Lithium cobalt oxide was used as the positive electrode material and lithium metal was used as the counter electrode. Non-aqueous electrolytes 1#~7# were injected respectively to assemble button cells 1#~7#. The room temperature cycle performance, high temperature cycle performance and low temperature discharge performance were tested respectively. The test conditions are as follows.

[0058] Normal temperature cycle performance: At room temperature (25°C), the button battery is charged and discharged at 1.0C / 1.0C (the battery discharge capacity is recorded as C 0 ), the upper voltage limit is 4.4V, and then 1.0C / 1.0C charging and discharging is performed at room temperature for 400 cycles (the battery discharge capacity is recorded as C 1 ), the capacity retention rate is calculated according to the following formula: Capacity retention rate = (C 1 / C 0 )*100% High temperature cycle performance: Under high temperature (45°C) conditions, the button cell is charged and discharged at 1.0C / 1.0C (the battery discharge capacity is C 0 ), the upper limit voltage is 4.4V, and then 1.0C / 1.0C charging and discharging is performed at room temperature for 400 cycles (the battery discharge capacity is C 1 ), the capacity retention rate is calculated according to the following formula: Capacity retention rate = (battery capacity after 400 cycles C 1 / Battery initial capacity C 0 )*100% Low temperature discharge performance: At room temperature (25°C), the button cell is charged and discharged at 0.5C / 0.5 (battery cut-off voltage is 3.0V, discharge capacity is C 0 ), the upper limit voltage is 4.4V (cut-off current 0.05C). Then the battery is fully charged to 4.4V (cut-off current 0.05C) at 0.5C at room temperature (25℃), and then the battery is transferred to -20℃ and left for 4h, and discharged to 3.0V at 0.5C, with a discharge capacity of C 1 , calculate the capacity retention rate according to the following formula: Capacity retention rate = (C 1 / C 0 )*100% Table 1 Electrochemical performance test results of each example

[0059] It can be seen from the test results in Table 1 that the vinyl sulfate compounds of the present invention have a more obvious effect on improving the room temperature cycle performance, high temperature cycle performance and low temperature performance of button batteries compared with PES and DTD. This may be because the vinyl sulfate compounds of the present invention contain two vinyl sulfate structures, which makes them show higher activity and stability in the electrolyte, and can further increase the content of sulfur and oxygen elements on the SEI film, making the SEI film more stable in high voltage, high temperature or low temperature environment, thereby achieving the effect of improving the room temperature cycle performance, high temperature cycle performance and low temperature performance of button batteries.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A vinyl sulfate compound, characterized in that: It has the structure shown in Formula 1: 。 2. A method for synthesizing vinyl sulfate compounds as claimed in claim 1, characterized in that: Includes steps: (1) reacting diacetone-D-mannitol, an amide acetal compound, and a first organic solvent at room temperature, performing a first reduced pressure distillation to obtain an intermediate A, and then adding iodomethane and a second organic solvent to the intermediate A for a reflux reaction to obtain an intermediate product A; (2) The intermediate product A is dissolved in a third organic solvent, an acid compound is added, and a deprotection reaction is carried out at room temperature, followed by a second reduced pressure distillation to obtain an intermediate product B, an alkaline catalyst and a fourth organic solvent are added to the intermediate product B, a sulfonylating agent is added dropwise, and a sulfonylating reaction is carried out at room temperature, and a vinyl sulfate compound is obtained after post-treatment.

3. The method for synthesizing vinyl sulfate compounds according to claim 2, characterized in that: The molar ratio of the diacetone-D-mannitol, the amide acetal compound and the methyl iodide is 1:2.1-3:2-2.5, the temperature of the reflux reaction is 60° C.-120° C., and the time of the reflux reaction is 4 h-24 h.

4. The method for synthesizing vinyl sulfate compounds according to claim 2, characterized in that: The molar ratio of the intermediate product A, the acid compound, the alkaline catalyst and the sulfonylating agent is 1:2-5:2-2.5:2.5-3, and the sulfonylation reaction time is 1h-24h.

5. The method for synthesizing vinyl sulfate compounds according to claim 2, characterized in that: The sulfonylating agent is selected from sulfonyl fluoride or sulfonyl chloride, the dropping temperature of the sulfonylating agent is -15°C to 10°C, and the dropping rate is 1g / h to 120g / h.

6. The method for synthesizing vinyl sulfate compounds according to claim 2, characterized in that: The amide acetal compound is selected from at least one of N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide diisopropyl acetal, N,N-diethylformamide dimethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide di-tert-butyl acetal, N,N-dimethylformamide dineopentyl acetal, N,N-dimethylformamide dibenzyl acetal and N,N-dimethylformamide dibutyl acetal.

7. The method for synthesizing vinyl sulfate compounds according to claim 2, characterized in that: The acid compound is selected from at least one of hydrochloric acid, Amberlyst15 dry, trifluoroacetic acid, Amberlyst15 wet, acetic acid, sulfuric acid, and acetic anhydride; the alkaline catalyst is selected from at least one of triethylamine, pyridine, DMAP, 2,6-lutidine, 1-pyridine-4-piperidine, cesium carbonate, sodium hydroxide, sodium methoxide, potassium tert-butoxide, potassium carbonate, zinc acetate, DBU, DIPEA, tetramethylethylenediamine, and N-methylmorpholine.

8. The method for synthesizing vinyl sulfate compounds according to claim 2, characterized in that: The first organic solvent, the second organic solvent, the third organic solvent and the fourth organic solvent are each independently selected from at least one of nitrile solvents, halogenated hydrocarbon solvents, ketone solvents, ether solvents, ester solvents, alcohol solvents, aromatic hydrocarbon solvents, amide solvents, and sulfone solvents. The temperatures of the first reduced pressure distillation and the second reduced pressure distillation are each independently 40°C to 100°C, and the pressures of the first reduced pressure distillation and the second reduced pressure distillation are each independently 5mmHg to 1000mmHg.

9. The method for synthesizing vinyl sulfate compounds according to claim 2, characterized in that: The post-treatment includes washing, concentration, recrystallization and drying.

10. Use of the vinyl sulfate compound according to claim 1 or the vinyl sulfate compound prepared by the method for synthesizing the vinyl sulfate compound according to any one of claims 2 to 9 in a secondary battery.

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