Nitrogen-containing heterocyclic ring compound as well as preparation method and application thereof

Abstract

The invention provides a nitrogen-containing heterocyclic compound as well as a preparation method and application thereof. The structural formula of the nitrogen-containing heterocyclic ring compound is shown as a formula I, R1 is SO2F or CH2-(CH2) n-SO2F, R2 and R3 are respectively and independently M, SO2F or CH2-(CH2) n-SO2F, n is an integer of 1-10, and M is hydrogen or alkali metal. According to the nitrogen-containing heterocyclic ring compound, reactive hydrogen protons on the acetaldehyde ammonia tripolymer are partially or completely substituted, and the negative influence of the reactive hydrogen protons on the battery performance can be weakened. In-ring hybridization and an N-S bond structure of the nitrogen-containing heterocyclic ring compound can efficiently complex metal ions, so that the nitrogen-containing heterocyclic ring compound can be used as an electrolyte additive, and the problem of dissolution of the metal ions in the positive electrode of the battery is solved. Active hydrogen protons are partially or completely replaced by sulfuryl fluoride or alkyl sulfuryl fluoride functional groups, and the ionic conductivity and thermal stability of the nitrogen-containing heterocyclic ring compound can be improved by the sulfuryl fluoride functional groups, so that the rate capability and high-temperature performance of the battery are improved. And the formula I of the # imgabs0 # is shown in the specification.

Description

Technical Field

[0001] The present invention relates to the technical field of material synthesis, and in particular to a compound used in a battery, and more particularly to a nitrogen-containing heterocyclic compound, a preparation method and application thereof. Background Art

[0002] In energy storage devices such as lithium-ion batteries and sodium-ion batteries, the performance of the positive electrode material directly affects the overall performance of the battery. However, during the battery charging and discharging process, especially under high temperature and high voltage conditions, the transition metal ions at the interface of the positive electrode material will partially dissolve into the electrolyte. For example, elements such as nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe) in lithium-ion batteries, and elements such as chromium (Cr), iron (Fe), and nickel (Ni) in sodium-ion batteries may all dissolve under specific conditions. The dissolution of metal ions has a negative impact on the battery's capacity, cycle life, and self-discharge performance. For example, dissolved transition metal ions such as Ni and Mn will be corroded by HF, destroying the stability of the material structure and causing the battery's cycle performance to decay rapidly. In addition, these dissolved metal ions may also cause the electrolyte to decompose, forming a surface film with large impedance and instability, further reducing the battery's coulombic efficiency and cycle performance.

[0003] In addition, trithiocyanate is a good heavy metal ion remover. Its sodium salt hydrate (TMT-3Na9H2O) was first reported in US Patent US4849517A. It reacts with trithiocyanate anions to remove Ni in the solution. + , Pb 2+ , Cu 2+ 、Ag + 、Zn 2+ 、Cd 2+ , Hg 2+ When the metal ions form stable complexes and precipitate, the purpose of removing heavy metal ions can be achieved.

[0004] Acetaldehyde ammonia trimer has a similar functional skeleton to trithiocyanate. Adding it to the electrolyte to regulate the electrolyte components can inhibit the dissolution of metal ions. However, since acetaldehyde ammonia trimer contains many active hydrogen protons, if acetaldehyde ammonia trimer is used in a battery, its active hydrogen protons may react with lithium hexafluorophosphate or other components in the electrolyte to affect the battery's initial charge and discharge capacity, internal resistance, cycle life and volume, etc. Therefore, there are few reports on the use of acetaldehyde ammonia trimer in battery systems. Summary of the invention

[0005] Based on the above problems, the purpose of the present invention is to provide a nitrogen-containing heterocyclic compound, a preparation method and an application thereof, wherein the nitrogen-containing heterocyclic compound modifies the acetaldehyde ammonia trimer and partially or completely replaces the active hydrogen protons thereon to weaken the influence of the active hydrogen protons on the battery performance. In addition, by introducing sulfuryl fluoride or alkyl sulfonyl fluoride functional groups, the battery performance can be further improved.

[0006] To achieve the above object, the present invention provides a nitrogen-containing heterocyclic compound in the first aspect, the structural formula of which is shown in Formula I, wherein R1 is SO2F or CH2-(CH2) n -SO2F, R2 and R3 are each independently M, SO2F or CH2-(CH2) n -SO2F, n is an integer of 1 to 10, and M is hydrogen or an alkali metal.

[0007] Formula I The nitrogen-containing heterocyclic compound of the present invention is a compound shown in Formula I, which partially or completely replaces the active hydrogen protons on the acetaldehyde ammonia trimer, and can weaken the negative impact of the active hydrogen protons on battery performance. The intra-ring hybridization and NS bond structure of the nitrogen-containing heterocyclic compound can efficiently complex metal ions, so the nitrogen-containing heterocyclic compound can be used as an electrolyte additive to solve the dissolution problem of metal ions in the positive electrode of the battery and improve the cycle performance of the battery. In addition, the nitrogen-containing heterocyclic compound of the present invention uses sulfuryl fluoride or alkylsulfonyl fluoride functional groups to partially or completely replace the active hydrogen protons, and the sulfonyl fluoride group can improve the ionic conductivity and thermal stability of the nitrogen-containing heterocyclic compound, and can improve the rate performance and high temperature performance of the battery when used in the battery.

[0008] As a technical solution of the present invention, n is an integer of 1 to 2, and M is hydrogen or lithium.

[0009] As a technical solution of the present invention, the nitrogen-containing heterocyclic compound is at least one of Compounds 1 to 5.

[0010]

[0011] Compound 1 Compound 2 Compound 3

[0012] Compound 4 Compound 5 The second aspect of the present invention provides a method for preparing a nitrogen-containing heterocyclic compound, comprising the steps of: (1) mixing acetaldehyde ammonia trimer and a first medium at a certain temperature to form a first solution; (2) adding sulfuryl fluoride or alkenyl sulfonyl fluoride to the first solution to react to obtain a product, and purifying the product, wherein the structural formula of the alkenyl sulfonyl fluoride is CH2=CH-(CH2): n-1 -SO2F, n is an integer from 1 to 10.

[0013] The preparation method of the present invention uses sulfuryl fluoride or alkenyl sulfonyl fluoride to modify acetaldehyde ammonia trimer to synthesize a series of nitrogen-containing heterocyclic compounds that weaken active hydrogen protons. The prepared nitrogen-containing heterocyclic compounds have both sulfuryl fluoride groups and intracyclic hybrid structures, which can greatly improve the cycle, rate and high-temperature performance of the battery. The preparation method of the nitrogen-containing heterocyclic compound of the present invention has easy-to-obtain raw materials, simple operation, high yield, mild conditions, low equipment requirements, and is suitable for large-scale industrial production.

[0014] As a technical solution of the present invention, the first medium is a first solvent or a combination of the first solvent and an organic base.

[0015] As a technical solution of the present invention, the first solvent includes at least one of an alcohol solvent, a nitrile solvent, a halogenated hydrocarbon solvent, an ether solvent, an ester solvent and a ketone solvent, and the organic base includes at least one of triethylamine, pyridine, 1,8-diazabicycloundec-7-ene and tetramethylpropylenediamine.

[0016] As a technical solution of the present invention, the purification treatment includes method ①: pretreatment after rough treatment, and the pretreatment includes cooling crystallization or chromatography column separation.

[0017] As a technical solution of the present invention, the purification treatment includes method ②: after evaporation and spin drying, dissolving with a second solvent, and then washing, dehydrating, filtering and concentrating the organic phase.

[0018] As a technical solution of the present invention, the purification treatment includes method ③: quenching the reaction after evaporation and spin drying, dissolving with a second solvent, and then washing, dehydrating, filtering and concentrating the organic phase.

[0019] As a technical solution of the present invention, the molar ratio of the acetaldehyde ammonia trimer to the sulfuryl fluoride is 1:1.0~3.2 or the molar ratio of the acetaldehyde ammonia trimer to the alkenyl sulfonyl fluoride is 1:1.0~3.2, the certain temperature is -20~40°C and the insulation time is 2~3h.

[0020] The third aspect of the present invention provides a method for preparing an alkali metal salt of a nitrogen-containing heterocyclic compound, comprising the steps of: (1) mixing acetaldehyde ammonia trimer and a first medium at a certain temperature to form a first solution; (ii) adding sulfuryl fluoride or alkenyl sulfonyl fluoride to the first solution to react and obtain a first product, wherein the alkenyl sulfonyl fluoride is CH2=CH-(CH2) n-1 -SO2F, n is an integer of 1 to 10, the molar ratio of the acetaldehyde ammonia trimer to the sulfuryl fluoride is 1:2.0 to 2.2 or the molar ratio of the acetaldehyde ammonia trimer to the alkenyl sulfonyl fluoride is 1:2.0 to 2.2, (iii) mixing the first product with a third solvent to form a second solution, An alkali metal compound is added and the pH value is adjusted to carry out a reaction, and the reactant is subjected to a purification treatment.

[0021] In the preparation method of the nitrogen-containing heterocyclic compound alkali metal salt of the present invention, acetaldehyde ammonia trimer is first modified with sulfuryl fluoride or alkenyl sulfonyl fluoride to partially replace active hydrogen protons to obtain a nitrogen-containing heterocyclic compound, and then an alkali metal compound is used to replace the remaining active hydrogen protons to obtain a nitrogen-containing heterocyclic compound alkali metal salt. In this preparation method, not only can all active hydrogen protons be replaced, but also sulfuryl fluoride groups can be introduced, and the obtained nitrogen-containing heterocyclic compound alkali metal salt can greatly improve the performance of the battery.

[0022] A fourth aspect of the present invention provides the use of the aforementioned nitrogen-containing heterocyclic compounds, the nitrogen-containing heterocyclic compounds prepared by the aforementioned method for preparing nitrogen-containing heterocyclic compounds, or the alkali metal salts of nitrogen-containing heterocyclic compounds prepared by the aforementioned method for preparing alkali metal salts of nitrogen-containing heterocyclic compounds as electrolyte additives. DETAILED DESCRIPTION

[0023] The structural formula of the nitrogen-containing heterocyclic compound of the present invention is shown in Formula I, wherein R1 is SO2F or CH2-(CH2) n -SO2F, R2 and R3 are each independently M, SO2F or CH2-(CH2) n -SO2F, n is an integer of 1 to 10, and M is hydrogen or an alkali metal. The alkali metal may be lithium, sodium, potassium, rubidium or cesium, preferably lithium or sodium. n may be, but is not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. Furthermore, n is an integer of 1 to 2, and M is hydrogen or lithium. The nitrogen-containing heterocyclic compound may be a nitrogen-containing heterocyclic compound or an alkali metal salt of a nitrogen-containing heterocyclic compound. Specifically, when M is hydrogen, R2 and R3 are each independently hydrogen, SO2F or CH2-(CH2) n -SO2F, the nitrogen-containing heterocyclic compound is a nitrogen-containing heterocyclic compound. When M is an alkali metal, R2 and R3 are each independently an alkali metal, SO2F or CH2-(CH2) n -SO2F, and at least one of R2 and R3 is an alkali metal, the nitrogen-containing heterocyclic compound is an alkali metal salt of a nitrogen-containing heterocyclic compound.

[0024]

[0025] Formula I Preferably, the nitrogen-containing heterocyclic compound may be at least one of Compounds 1 to 5. Compounds 1 to 4 are nitrogen-containing heterocyclic compounds, and Compound 5 is an alkali metal salt of a nitrogen-containing heterocyclic compound.

[0026]

[0027] Compound 1 Compound 2 Compound 3

[0028] Compound 4 Compound 5 The nitrogen-containing heterocyclic compounds of the present invention can be used as intermediates to synthesize various auxiliary agents, and can also be used as electrolyte additives. The nitrogen-containing heterocyclic compounds used as electrolyte additives in lithium-ion batteries can improve the electrochemical properties of lithium-ion batteries such as cycle, rate, and high temperature.

[0029] Lithium-ion batteries include positive electrode active materials, negative electrode active materials and electrolytes. The positive electrode active materials may be layered transition metal lithium oxides or olivine-type lithium compounds. The layered transition metal lithium oxides may be, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides (chemical formula LiNi x Co y Mn (1-x-y) M z O2, wherein 0.6≤x<0.9, x+y<1, 0≤z<0.08, M is at least one of Al, Mg, Zr and Ti) and coatings and dopants of the above materials. It is particularly suitable for lithium nickel cobalt manganese oxide ternary materials. These positive electrode active materials can be used alone or in combination of two or more.

[0030] The negative electrode active material includes at least one of a carbon-based material, a silicon-based material and a tin-based material. Among them, the carbon-based material may be, but is not limited to, at least one of artificial graphite, natural graphite, hard carbon, soft carbon, graphene and mesophase carbon microspheres. The silicon-based material may be, but is not limited to, at least one of a silicon element, a silicon-oxygen composite material, a silicon-carbon composite material and a silicon alloy material. The tin-based material may include a tin element, a tin-carbon composite material, a tin-oxygen composite material, and a tin alloy compound.

[0031] The electrolyte solution includes an electrolyte salt, a nonaqueous organic solvent, and additives.

[0032] The electrolyte salt may be, but is not limited to, at least one of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium methanesulfonate (LiCH3SO3), lithium trifluoromethylsulfonate (LiCF3SO3), lithium bis(oxalate)borate (C4BLiO8), lithium difluorooxalate borate (C2BF2LiO4), lithium difluorophosphate (LiPO2F2) and lithium difluorobis(oxalate)phosphate (LiDFBP). The non-aqueous organic solvent is selected from carbonates and / or carboxylates. Further, the non-aqueous organic solvent is selected from at least one of ethylene carbonate (PC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-butyrolactone, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, propyl propionate and butyl propionate.

[0033] The additive may include at least a nitrogen-containing heterocyclic compound. The structural formula of the nitrogen-containing heterocyclic compound is shown in Formula I. The nitrogen-containing heterocyclic compound accounts for 1.0-10.0% of the mass of the electrolyte. As an example, the proportion of the nitrogen-containing heterocyclic compound can be, but is not limited to, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0%, and 10.0%.

[0034] The preparation method of the nitrogen-containing heterocyclic compound of the present invention may include the following steps.

[0035] (1) Mixing acetaldehyde ammonia trimer and a first medium at a certain temperature to form a first solution.

[0036] (2) adding sulfuryl fluoride or alkenyl sulfonyl fluoride to the first solution to react and obtain a product, and purifying the product. The structural formula of alkenyl sulfonyl fluoride is CH2=CH-(CH2): n-1 -SO2F, n is an integer from 1 to 10.

[0037] In step (1), the first medium is a first solvent or a combination of the first solvent and an organic base. If the first medium is a first solvent, the acetaldehyde ammonia trimer and the first solvent are mixed at a certain temperature to form a first solution. If the first medium is a combination of the first solvent and an organic base, the acetaldehyde ammonia trimer, the organic base and the first solvent are uniformly mixed and mixed at a certain temperature to form a first solution. Further addition of an organic base can neutralize the leaving group and promote the progress of the electrophilic reaction in step (2). The boiling point of the first solvent is less than 100°C, that is, the first solvent is a low boiling point solvent. Specifically, the first solvent includes at least one of an alcohol solvent, a nitrile solvent, a halogenated hydrocarbon solvent, an ether solvent, an ester solvent and a ketone solvent. More specifically, the alcohol solvent is methanol, ethanol or isopropanol. The nitrile solvent is acetonitrile or butyronitrile. The halogenated hydrocarbon solvent is dichloromethane, chloroform, 1,2-dichloroethane or tetrachloroethane. The ether solvent is methyl tert-butyl ether, ethylene glycol dimethyl ether, tetrahydrofuran or dioxane, and the ester is dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl acetate, ethyl acetate or propyl acetate. The ketone solvent is acetone, cyclohexanone or 4-methyl-2-pentanone. Preferably, the first solvent is acetonitrile, ethanol or dichloromethane. The organic base includes at least one of triethylamine, pyridine, 1,8-diazabicycloundec-7-ene (DBU) and tetramethylpropylenediamine (TMPDA).

[0038] In step (1), the certain temperature is -20 to 40°C. As an example, the temperature may be, but is not limited to, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, and 40°C. The insulation time is 2 to 3 hours. As an example, it may be, but is not limited to, 2 hours or 3 hours.

[0039] In step (2), the molar ratio of acetaldehyde ammonia trimer to sulfuryl fluoride is 1:1 to 3.2. Specifically, when the molar ratio of acetaldehyde ammonia trimer to sulfuryl fluoride is close to 1:1, only R1 in Formula I is SO2F. When the molar ratio of acetaldehyde ammonia trimer to sulfuryl fluoride is close to 1:2, R1 in Formula I is SO2F, and one of R2 and R3 is SO2F. When the molar ratio of acetaldehyde ammonia trimer to sulfuryl fluoride is close to 1:3, R1, R2, and R3 in Formula I are all SO2F. The molar ratio of acetaldehyde ammonia trimer to alkenyl sulfonyl fluoride is 1:1 to 3.2. Specifically, when the molar ratio of acetaldehyde ammonia trimer to alkenyl sulfonyl fluoride is close to 1:1, only R1 in Formula I is CH2-(CH2) n -SO2F. When the molar ratio of acetaldehyde ammonia trimer to olefin sulfonyl fluoride is close to 1:2, R1 in Formula I is CH2-(CH2) n -SO2F, one of R2 and R3 is CH2-(CH2) nWhen the molar ratio of acetaldehyde ammonia trimer to olefin sulfonyl fluoride is close to 1:3, R1, R2, and R3 in Formula I are all CH2-(CH2) n -SO2F.

[0040] The reaction of acetaldehyde ammonia trimer with sulfuryl fluoride, and acetaldehyde ammonia trimer with olefin sulfonyl fluoride can be monitored by LC / MS or GC / MS to monitor the end point of the reaction, and the reaction is stopped after detecting the peak without raw materials after a certain reaction time. The reaction time is 2~3h, and the reaction temperature is 0~40℃. The reaction temperature is low, which can effectively reduce energy consumption. Furthermore, the reaction time can be but not limited to 2h, 3h, and the reaction temperature can be but not limited to 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃. Sulfuryl fluoride is a gas, and the reaction conditions of acetaldehyde ammonia trimer and sulfuryl fluoride are gas-liquid reaction under high pressure. The reaction device is preferably a high-pressure reactor, and the introduction rate of sulfuryl fluoride gas can be controlled by controlling the pressure in the high-pressure reactor (≤0.5MPa) during operation. Alkenyl sulfonyl fluoride is a liquid, and the reaction device of acetaldehyde ammonia trimer and alkenyl sulfonyl fluoride is preferably a three-necked flask.

[0041] The product obtained after the reaction of acetaldehyde ammonia trimer with sulfuryl fluoride or acetaldehyde ammonia trimer with alkenyl sulfonyl fluoride can be further purified. The purification method can be as follows.

[0042] Method ①: Pretreatment after rough treatment, including cooling crystallization or chromatography column separation, followed by vacuum drying. The crystallization temperature of cooling crystallization is -20~10℃, and the cooling crystallization time is 1~5h. The vacuum drying temperature is 80~150℃, and the drying time is 8~30h.

[0043] Method ②: After evaporation and spin drying, a second solvent is used for dissolution, and then the organic phase is washed, dehydrated, filtered and concentrated. The second solvent is an ester solvent, a halogenated hydrocarbon solvent or an ether solvent. More specifically, the ester solvent is dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl acetate, ethyl acetate or propyl acetate. The halogenated hydrocarbon solvent is dichloromethane, chloroform, 1,2-dichloroethane or tetrachloroethane. The ether solvent is ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, tetrahydrofuran or dioxane. Preferably, the second solvent is ethyl acetate, dichloromethane or dichloroethane. Specifically, the organic phase is washed with brine and dehydrated and dried with anhydrous magnesium sulfate.

[0044] Method ③: After evaporation and spin drying, the reaction is quenched, and the second solvent is used for dissolution, and then the organic phase is washed, dehydrated, filtered, and concentrated. The quenching reaction can be carried out with deionized water or ice water.

[0045] The nitrogen-containing heterocyclic compound of the present invention can be further alkalized to prepare an alkali metal salt of the nitrogen-containing heterocyclic compound, and the preparation method thereof comprises the following steps.

[0046] (i) mixing acetaldehyde ammonia trimer and a first medium at a certain temperature to form a first solution.

[0047] (ii) adding sulfuryl fluoride or alkenyl sulfonyl fluoride to the first solution to react and obtain a first product. The structural formula of alkenyl sulfonyl fluoride is CH2=CH-(CH2) n-1 -SO2F, n is an integer from 1 to 10.

[0048] (iii) mixing the first product with a third solvent to form a second solution, adding an alkali metal compound to the second solution and adjusting the pH value to react, and purifying the reactant.

[0049] In step (i), the first medium is a first solvent or a combination of the first solvent and an organic base. If the first medium is a first solvent, the acetaldehyde ammonia trimer and the first solvent are mixed at a certain temperature to form a first solution. If the first medium is a combination of the first solvent and an organic base, the acetaldehyde ammonia trimer, the organic base and the first solvent are mixed evenly and mixed at a certain temperature to form a first solution. Further addition of an organic base can neutralize the leaving group and promote the progress of the electrophilic reaction in step (ii). The boiling point of the first solvent is less than 100°C, that is, the first solvent is a low boiling point solvent. Specifically, the first solvent includes at least one of an alcohol solvent, a nitrile solvent, a halogenated hydrocarbon solvent, an ether solvent, an ester solvent and a ketone solvent. More specifically, the alcohol solvent is methanol, ethanol or isopropanol. The nitrile solvent is acetonitrile or butyronitrile. The halogenated hydrocarbon solvent is dichloromethane, chloroform, 1,2-dichloroethane or tetrachloroethane. The ether solvent is methyl tert-butyl ether, ethylene glycol dimethyl ether, tetrahydrofuran or dioxane, and the ester is dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl acetate, ethyl acetate or propyl acetate. The ketone solvent is acetone, cyclohexanone or 4-methyl-2-pentanone. Preferably, the first solvent is acetonitrile, ethanol or dichloromethane. The organic base includes at least one of triethylamine, pyridine, 1,8-diazabicycloundec-7-ene (DBU) and tetramethylpropylenediamine (TMPDA). This certain temperature is -20~40℃. As an example, the temperature can be but not limited to -20℃, -15℃, -10℃, -5℃, 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃. The insulation time is 2~3h. As an example, it can be but not limited to 2h, 3h.

[0050] In step (ii), in order to satisfy the requirement that there are still active hydrogen protons remaining to react with sulfuryl fluoride, the molar ratio of acetaldehyde ammonia trimer and sulfuryl fluoride is 1:2.0~2.2. Specifically, when the molar ratio of acetaldehyde ammonia trimer to sulfuryl fluoride is close to 1:1, only R1 in Formula I is SO2F, and there are 2 active hydrogen protons remaining in the first product, which are subsequently replaced in whole or in part by alkali metals. When the molar ratio of acetaldehyde ammonia trimer to sulfuryl fluoride is close to 1:2, R1 in Formula I is SO2F, and one of R2 and R3 is SO2F and the other is an active hydrogen proton, indicating that there is 1 active hydrogen proton remaining in the first product, which is subsequently replaced in whole or in part by alkali metals. The molar ratio of acetaldehyde ammonia trimer to alkenyl sulfonyl fluoride is 1:2.0~2.2. Specifically, when the molar ratio of acetaldehyde ammonia trimer to alkenyl sulfonyl fluoride is close to 1:1, only R1 in Formula I is CH2-(CH2) n -SO2F, there are 2 active hydrogen protons left in the first product, which are subsequently replaced in whole or in part by alkali metals. When the molar ratio of acetaldehyde ammonia trimer to olefin sulfonyl fluoride is close to 1:2, R1 in formula I is CH2-(CH2) n -SO2F, one of R2 and R3 is CH2-(CH2) n -SO2F Another is an active hydrogen proton, indicating that there is still one active hydrogen proton left in the first product, which is subsequently replaced in whole or in part by an alkali metal. The reaction of acetaldehyde ammonia trimer with sulfuryl fluoride, and the reaction of acetaldehyde ammonia trimer with alkenyl sulfonyl fluoride can be monitored by LC / MS or GC / MS to monitor the end point of the reaction, and the reaction is stopped after detecting the peak without raw materials after a certain period of reaction. The reaction time is 2~3h, and the reaction temperature is 0~40℃. The reaction temperature is low, which can effectively reduce energy consumption. Furthermore, the reaction time can be but not limited to 2h, 3h, and the reaction temperature can be but not limited to 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃. Sulfuryl fluoride is a gas, and the reaction conditions of acetaldehyde ammonia trimer and sulfuryl fluoride are gas-liquid reaction under high pressure. The reaction device is preferably a high-pressure reactor. During operation, the introduction rate of sulfuryl fluoride gas can be controlled by controlling the pressure in the high-pressure reactor (≤0.5MPa). Since alkenylsulfonyl fluoride is a liquid, the reaction device of acetaldehyde ammonia trimer and alkenylsulfonyl fluoride is preferably a three-necked flask.

[0051] The product obtained after the reaction of acetaldehyde ammonia trimer with sulfuryl fluoride or acetaldehyde ammonia trimer with alkenyl sulfonyl fluoride can be directly subjected to step (iii) alkalization to obtain the alkali metal salt of the nitrogen-containing heterocyclic compound, or can be first purified to obtain the alkali metal salt of the nitrogen-containing heterocyclic compound and then alkalized.

[0052] The purification process can be carried out in various ways.

[0053] Method ①: Pretreatment after rough treatment, including cooling crystallization or chromatography column separation, followed by vacuum drying. The crystallization temperature of cooling crystallization is -20~10℃, and the cooling crystallization time is 1~5h. The vacuum drying temperature is 80~150℃, and the drying time is 8~30h.

[0054] Method ②: After evaporation and spin drying, a second solvent is used for dissolution, and then the organic phase is washed, dehydrated, filtered and concentrated. The second solvent is an ester solvent, a halogenated hydrocarbon solvent or an ether solvent. More specifically, the ester solvent is dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl acetate, ethyl acetate or propyl acetate. The halogenated hydrocarbon solvent is dichloromethane, chloroform, 1,2-dichloroethane or tetrachloroethane. The ether solvent is ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, tetrahydrofuran or dioxane. Preferably, the second solvent is ethyl acetate, dichloromethane or dichloroethane. Specifically, the organic phase is washed with brine and dehydrated and dried with anhydrous magnesium sulfate.

[0055] Method ③: After evaporation and spin drying, the reaction is quenched, and the second solvent is used for dissolution, and then the organic phase is washed, dehydrated, filtered, and concentrated. The quenching reaction can be carried out with deionized water or ice water.

[0056] In step (iii), the third solvent is at least one of an alcohol solvent, a nitrile solvent, an aqueous solvent, an ester solvent and a ketone solvent. Specifically, the alcohol solvent is methanol, ethanol or isopropanol. The nitrile solvent is acetonitrile or butyronitrile. The ester solvent is dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl acetate, ethyl acetate or propyl acetate. The ketone solvent is acetone, cyclohexanone or 4-methyl-2-pentanone. Preferably, the third solvent is methanol, water or ethanol.

[0057] The alkali metal compound is a lithium compound, a sodium compound, a potassium compound, a rubidium compound or a cesium compound. Specifically, the lithium compound is lithium hydroxide, lithium hydroxide monohydrate, lithium carbonate, lithium methoxide, lithium ethoxide or lithium tert-butoxide. The sodium compound is sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium methoxide, sodium ethoxide or sodium tert-butoxide. The potassium compound is potassium hydroxide, potassium carbonate, potassium bicarbonate, potassium methoxide or potassium tert-butoxide. The rubidium compound is rubidium hydroxide or rubidium carbonate. The cesium compound is cesium hydroxide, cesium hydroxide monohydrate, cesium carbonate or cesium bicarbonate. Preferably, the lithium compound is lithium hydroxide or lithium hydroxide monohydrate, the sodium compound is sodium hydroxide or sodium carbonate, the potassium compound is potassium hydroxide or potassium carbonate, the rubidium compound is rubidium hydroxide, and the cesium compound is cesium hydroxide or cesium hydroxide monohydrate.

[0058] The pH value of the alkalization reaction of the first product and the alkali metal compound is 7-8. The reaction temperature is 40-60°C. As an example, the temperature can be, but not limited to, 40°C, 45°C, 50°C, 55°C, and 60°C. The reaction time is 1-5h. As an example, the time can be, but not limited to, 1h, 2h, 3h, 4h, and 5h. The purification process may include concentration, cooling crystallization, filtration, and drying in sequence. Specifically, the temperature of cooling crystallization is -20-10°C, the time of cooling crystallization is 1-5h, the temperature of drying is 80-150°C, and the time of drying is 8-30h.

[0059] 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. If the specific conditions are not specified in the embodiments and comparative examples, they can be carried out according to conventional conditions or conditions recommended by the manufacturer. If the reagents or instruments used do not specify the manufacturer, they are all conventional products that can be obtained commercially. The stainless steel autoclave or three-necked flask used in the embodiment can use existing devices. For example, the stainless steel autoclave can be equipped with speed-regulating stirring, electric heating, cooling coils, temperature and pressure display instruments, and the gas feed port of the autoclave is connected to the sulfuryl fluoride cylinder through the connecting pipe fittings of the stainless steel pipe, and the introduction rate and amount of sulfuryl fluoride can be controlled by the gas flowmeter and the electronic balance. The three-necked flask can be equipped with speed-regulating stirring, constant pressure funnel, and acid gas absorber.

[0060] Part I: Preparation of nitrogen-containing heterocyclic compounds Example 1 This embodiment is to prepare a nitrogen-containing heterocyclic compound, and its preparation method includes the following steps.

[0061] (1) 20 g (0.155 mol) of acetaldehyde ammonia trimer, 18.7 g (0.185 mol) of triethylamine and 120 mL of acetonitrile were placed in a 500 mL stainless steel autoclave. The jacket temperature of the autoclave was set to 0°C, and condensed water at -10°C was passed through the cooling coil. The mixture was stirred at a constant speed for 10 min to obtain the first solution.

[0062] (2) 15.8 g (0.155 mol) of sulfuryl fluoride gas was introduced for reaction, the reaction pressure was 0.5 MPa, the reaction time was 2.6 h, after the reaction was completed, the intermediate was evaporated and dried to obtain an intermediate, the intermediate was dissolved in ethyl acetate, the organic phase was filtered, the organic phase was washed 3 times with 100 mL of 5 wt.% sodium chloride aqueous solution, and then dried with 8 g of anhydrous magnesium sulfate, filtered, and concentrated to obtain a crude product. The crude product was cooled and crystallized at -10°C for 3 h, filtered, and vacuum dried at 120°C for 12 h to obtain 30.1 g of compound 1, and the yield of compound 1 was 92%.

[0063] 1H NMR of compound 1 (400 MHz, deuterated DMSO, ppm): δ 1.07 (s, J = 5.8 Hz, 2H), 1.13-1.17 (d, J = 3.2 Hz, 9H), 3.85-3.88 (dd, J = 5.6 Hz, 3H).

[0064] 13C{1H}NMR of compound 1 (100 MHz, deuterated DMSO, ppm): δ18.9, 22.8, 63.5, 69.8.

[0065] The reaction equation for preparing compound 1 in this example is as follows:

[0066] Example 2 This embodiment is to prepare a nitrogen-containing heterocyclic compound, and its preparation method includes the following steps.

[0067] (1) 20 g (0.155 mol) of acetaldehyde ammonia trimer, 50.2 g (0.496 mol) of triethylamine and 160 mL of acetonitrile were placed in a 500 mL stainless steel autoclave. The jacket temperature of the autoclave was set to 0°C, and condensed water at -10°C was passed through the cooling coil. The mixture was stirred at a constant speed for 10 min to obtain the first solution.

[0068] (2) 47.4 g (0.465 mol) of sulfuryl fluoride gas was introduced for reaction, the reaction pressure was 0.5 MPa, the reaction time was 2.2 h, after the reaction was completed, the intermediate was evaporated and dried to obtain an intermediate, the intermediate was dissolved in ethyl acetate, the organic phase was filtered, the organic phase was washed 3 times with 100 mL of 5 wt.% sodium chloride aqueous solution, and then dried with 8 g of anhydrous magnesium sulfate, filtered, and concentrated to obtain a crude product. The crude product was separated by chromatography column (EA / PE = 3:7) to obtain a wet product, and the wet product was vacuum dried at 80 ° C for 24 h to obtain 49.5 g of compound II, and the yield of compound II was 85%.

[0069] 1H NMR of Compound 2 (400 MHz, deuterated DMSO, ppm): 1.17-1.21 (d, J=3.4 Hz, 9H), 3.81-3.4 (dd, J=5.8 Hz, 3H).

[0070] 13C{1H} NMR (100 MHz, deuterated DMSO, ppm) of compound 2: δ15.0, 57.8.

[0071] The reaction equation for preparing compound 2 in this example is as follows:

[0072] Example 3 This embodiment is to prepare a nitrogen-containing heterocyclic compound, and its preparation method includes the following steps.

[0073] (1) Add 20 g (0.155 mol) of acetaldehyde ammonia trimer and 120 mL of anhydrous ethanol into a 500 mL three-necked flask, place the three-necked flask in an ice-water bath, control the temperature of the ice-water bath to 0°C, and stir at a constant speed for 20 min to obtain the first solution.

[0074] (2) 17.1 g (0.155 mol) of vinylsulfonyl fluoride (structural formula: CH2=CH-SO2F) was added to react for 2.4 h. After the reaction was completed, the first intermediate was evaporated to dryness to obtain the first intermediate. Ice water was added to the first intermediate to quench the reaction to obtain the second intermediate. The second intermediate was dissolved in ethyl acetate, and the organic phase was filtered. The organic phase was washed three times with 100 mL of 5 wt.% sodium chloride aqueous solution, dried with 8 g of anhydrous magnesium sulfate, filtered, and concentrated to obtain a crude product. The crude product was cooled and crystallized at -10°C for 3.2 h, filtered, and vacuum dried at 100°C for 12 h to obtain 33.4 g of compound III. The yield of compound III was 90%.

[0075] 1H NMR of compound 3 (400 MHz, deuterated DMSO, ppm): δ1.07 (s, J=5.8 Hz, 2H), 1.14-1.18 (d, J=3.2 Hz, 9H), 2.90-2.94 (t, J=3.6 Hz, 2H), 3.49-3.52 (t, J=3.6 Hz, 2H), 3.85-3.88 (dd, J=5.6 Hz, 3H).

[0076] 13C{1H}NMR of compound 3 (100 MHz, deuterated DMSO, ppm): δ 20.6, 22.8, 40.3, 58.9, 70.1, 76.2.

[0077] The reaction equation for preparing compound three in this example is as follows:

[0078] Example 4 This embodiment is to prepare a nitrogen-containing heterocyclic compound, and its preparation method includes the following steps.

[0079] (1) Add 20 g (0.155 mol) of acetaldehyde ammonia trimer and 120 mL of anhydrous ethanol into a 500 mL three-necked flask, place the three-necked flask in an ice-water bath, control the temperature of the ice-water bath to 0°C, and stir at a constant speed for 20 min to obtain the first solution.

[0080] (2) 51.3 g (0.465 mol) of vinylsulfonyl fluoride (structural formula: CH2=CH-SO2F) was introduced into the reaction mixture for 2.5 h. After the reaction was completed, the mixture was evaporated to dryness to obtain the first intermediate. Ice water was added to the first intermediate to quench the reaction and obtain the second intermediate. The second intermediate was dissolved in dichloromethane and the organic phase was filtered. The organic phase was washed three times with 100 mL of a 5 wt.% sodium chloride aqueous solution, dried with 8 g of anhydrous magnesium sulfate, filtered, and concentrated to obtain a crude product. The crude product was cooled and crystallized at -20°C for 2.8 h, filtered, and vacuum dried at 100°C for 24 h to obtain 59.8 g of compound 4. The yield of compound 4 was 84%.

[0081] 1H NMR of compound 4 (400 MHz, deuterated DMSO, ppm): δ 1.14-1.18 (d, J = 3.2 Hz, 9H), 2.90-2.93 (t, J = 3.2 Hz, 6H), 3.48-3.51 (t, J = 3.6 Hz, 6H), 3.85-3.88 (dd, J = 5.6 Hz, 3H).

[0082] 13C{1H}NMR (100 MHz, deuterated DMSO, ppm) of compound 4: δ 26.0, 40.9, 58.9, 58.9, 81.5.

[0083] The reaction equation for preparing compound 4 in this embodiment is as follows:

[0084] Example 5 This embodiment is to prepare an alkali metal salt of a nitrogen-containing heterocyclic compound, and the preparation method thereof includes the following steps.

[0085] (1) 20 g (0.155 mol) of acetaldehyde ammonia trimer, 18.7 g (0.185 mol) of triethylamine and 120 mL of acetonitrile were placed in a 500 mL stainless steel autoclave. The jacket temperature of the autoclave was set to 0°C, and condensed water at -10°C was passed through the cooling coil. The mixture was stirred at a constant speed for 10 min to obtain the first solution.

[0086] (2) 15.8 g (0.155 mol) of sulfuryl fluoride gas was introduced for reaction, the reaction pressure was 0.5 MPa, the reaction time was 2.6 h, after the reaction was completed, the intermediate was evaporated and dried to obtain an intermediate, the intermediate was dissolved in ethyl acetate, the organic phase was filtered, the organic phase was washed 3 times with 100 mL of 5 wt.% sodium chloride aqueous solution, and then dried with 8 g of anhydrous magnesium sulfate, filtered, and concentrated to obtain a crude product. The crude product was cooled and crystallized at -10 ° C for 3 h, filtered, and vacuum dried at 120 ° C for 12 h to obtain 30.1 g of product.

[0087] (3) 20 g (0.095 mol) of the product and 100 mL of methanol were placed in a 500 mL three-necked flask to obtain a second solution. The three-necked flask was placed in a water bath, the temperature of the water bath was controlled at 50°C, and the solution was stirred at a constant speed for 25 min. 4.5 g (0.189 mol) of anhydrous lithium hydroxide was added in batches, and the pH value was adjusted to 7.2, and the reaction was continued for 2 h. After the reaction, the product was concentrated, cooled and crystallized at -10°C for 2 h, filtered, and vacuum dried at 150°C for 24 h to obtain 18.0 g of compound 5, and the yield of compound 5 was 85%.

[0088] 1H NMR of Compound 5 (400 MHz, deuterated DMSO, ppm): δ 1.13-1.17 (d, J=3.2 Hz, 9H), 3.85-3.88 (dd, J=5.6 Hz, 3H).

[0089] 13C{1H}NMR (100 MHz, deuterated DMSO, ppm) of compound 5: δ 25.4, 35.0, 70.2, 82.7.

[0090] The reaction equation for preparing compound 5 in this example is as follows:

[0091]

[0092] Part II: Application of nitrogen-containing heterocyclic compounds in batteries 1.1 Preparation of non-aqueous electrolyte In a glove box filled with nitrogen (O2 <1ppm, H2O <1ppm), 86g of the mixed solvent obtained by mixing diethyl carbonate (DEC) and ethyl methyl carbonate (EMC) in a mass ratio of 1:1 was used as an organic solvent, and 1.5g of the nitrogen-containing heterocyclic compound obtained in Examples 1 to 6 was added to obtain a mixed solution. The mixed solution was sealed and packaged and placed in a quick freezer (-4°C) for 2h and then taken out. In a glove box filled with nitrogen (O2 <1ppm, H2O <1ppm), 12.5g of lithium hexafluorophosphate (LiPF6) was slowly added to the mixed solution, and non-aqueous electrolytes 1 to 5# were prepared after mixing evenly.

[0093] In a glove box filled with nitrogen (O2 <1ppm, H2O <1ppm), diethyl carbonate (DEC) and ethyl methyl carbonate (EMC) were mixed in a mass ratio of 1:1 to obtain 87.5g of a mixed solvent as an organic solvent. The organic solvent was sealed and packaged and placed in a quick freezer (-4°C) for 2h before being taken out. In a glove box filled with nitrogen (O2 <1ppm, H2O <1ppm), 12.5g of lithium hexafluorophosphate (LiPF6) was slowly added to the mixed solution, and after mixing evenly, non-aqueous electrolyte 6# was prepared.

[0094] 1.2 Preparation of positive electrode Lithium iron phosphate, conductive agent SuperP, adhesive PVDF and carbon nanotubes (CNT) are mixed evenly in a mass ratio of 96.5:1.5:1:1 to prepare a lithium-ion battery positive electrode slurry with a certain viscosity, which is then coated on both sides of an aluminum foil and dried and rolled to obtain a positive electrode sheet, thereby making a lithium-ion battery positive electrode sheet that meets the requirements.

[0095] 1.3 Preparation of negative electrode Artificial graphite is mixed with conductive agent SuperP, thickener CMC and adhesive SBR (styrene-butadiene rubber latex) in a mass ratio of 95:1.5:1.0:2.5 to make a slurry, which is evenly mixed. The mixed slurry is applied on both sides of the copper foil, and then dried and rolled to obtain a negative electrode sheet, thereby making a lithium-ion battery negative electrode sheet that meets the requirements.

[0096] 1.4 Preparation of lithium-ion batteries The positive electrode sheet, negative electrode sheet and separator prepared by the above process are laminated to form a lithium-ion battery with a thickness of 4.7mm, a width of 55mm, a length of 60mm and a total capacity of 2Ah. They are vacuum-baked at 75°C for 10h and non-aqueous electrolytes 1~6# are injected respectively. After standing for 24h, they are charged to 3.65V with a constant current of 0.1C (200mA), and then charged with a constant voltage of 3.65V until the current drops to 0.05C (100mA); then discharged to 2.5V with 0.2C (400mA), and the charge and discharge are repeated twice. Finally, the battery is charged to 3.65V with 0.1C (200mA), and lithium-ion batteries 1~6# are made.

[0097] The performance of lithium-ion batteries 1~6# was tested. The test results are shown in Table 1. The test conditions are as follows.

[0098] (1) High rate performance test At room temperature (25°C), the lithium-ion battery was charged and discharged at 3.0C / 3.0C (the battery discharge capacity was recorded as C0) with an upper voltage limit of 4.2V; then charged and discharged at 3.0C / 3.0C for 500 cycles, and the capacity retention rate was calculated.

[0099] Capacity retention rate = (battery capacity C1 after 500 cycles / battery initial capacity C0) * 100% (2) High temperature storage performance test At room temperature (25°C), the lithium-ion battery was charged and discharged at 0.5C / 0.5C (the battery discharge capacity was recorded as C0), the upper limit voltage was 4.2V, and then the battery was charged to 4.2V under 0.5C constant current and constant voltage conditions, and the battery thickness was measured (the thickness was recorded as D0). The battery was placed in a 60°C oven for 30 days, taken out and the battery thickness was measured (the thickness was recorded as D1), and the battery was placed in a 25°C environment and discharged at 0.5C (the discharge capacity was recorded as C1), and the capacity retention rate and thickness expansion rate were calculated.

[0100] Capacity retention rate = (C1 / C0)*100% Thickness expansion rate = (D1-D0 / D0)*100% (3) High temperature cycle performance test Under high temperature (45°C) conditions, the lithium-ion battery is charged and discharged at 1.0C / 1.0C once (the battery discharge capacity is C0) with an upper voltage of 4.2V, and then charged and discharged at 1.0C / 1.0C for 400 cycles at room temperature (the battery discharge capacity is C1), and the capacity retention rate is calculated.

[0101] Capacity retention rate = (C1 / C0)*100% Table 1 Electrochemical performance test results of each example

[0102] From the results in Table 1, it can be seen that the rate, high-temperature storage and high-temperature cycle performance of lithium-ion batteries 1 to 5# are better than those of lithium-ion battery 6#. This is because nitrogen-containing heterocyclic compounds are used as additives in lithium-ion batteries 1 to 5#. Nitrogen-containing heterocyclic compounds can efficiently complex metal ions to avoid the dissolution of metal ions in the positive electrode of the battery. In addition, sulfuryl fluoride or alkylsulfonyl fluoride functional groups are used to partially or completely replace active hydrogen protons. The sulfonyl fluoride group can improve the ionic conductivity and thermal stability of nitrogen-containing heterocyclic compounds, so the battery has better rate performance and high-temperature performance.

[0103] 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 nitrogen-containing heterocyclic compound, characterized in that: The structural formula is shown in Formula I, wherein R1 is SO2F or CH2-(CH2) n -SO2F, R2 and R3 are each independently M, SO2F or CH2-(CH2) n -SO2F, n is an integer of 1 to 10, M is hydrogen or an alkali metal, Formula I.

2. The nitrogen-containing heterocyclic compound according to claim 1, characterized in that n is an integer of 1 to 2, and M is hydrogen or lithium.

3. The nitrogen-containing heterocyclic compound according to claim 1, characterized in that is at least one of Compound 1 to Compound 5, Compound 1 Compound 2 Compound 3 Compound 4 Compound 5 4. A method for preparing a nitrogen-containing heterocyclic compound, characterized in that: Includes steps: (1) mixing acetaldehyde ammonia trimer and a first medium at a certain temperature to form a first solution; (2) adding sulfuryl fluoride or alkenyl sulfonyl fluoride to the first solution to react to obtain a product, and purifying the product, wherein the structural formula of the alkenyl sulfonyl fluoride is CH2=CH-(CH2): n-1 -SO2F, n is an integer from 1 to 10.

5. The method for preparing a nitrogen-containing heterocyclic compound according to claim 4, characterized in that: The first medium is a first solvent or a combination of a first solvent and an organic base.

6. The method for preparing a nitrogen-containing heterocyclic compound according to claim 5, characterized in that: The first solvent includes at least one of an alcohol solvent, a nitrile solvent, a halogenated hydrocarbon solvent, an ether solvent, an ester solvent and a ketone solvent, and the organic base includes at least one of triethylamine, pyridine, 1,8-diazabicycloundec-7-ene and tetramethylpropylenediamine.

7. The method for preparing a nitrogen-containing heterocyclic compound according to claim 4, characterized in that: The purification treatment includes any one of the methods ① to ③, Method ①: Pretreatment after rough treatment, the pretreatment includes cooling crystallization or chromatography column separation; Method ②: After evaporation and spin drying, the second solvent is used for dissolution, and then the organic phase is washed, dehydrated, filtered and concentrated; Method ③: After evaporation and spin drying, the reaction is quenched, a second solvent is used for dissolution, and then the organic phase is washed, dehydrated, filtered and concentrated.

8. The method for preparing a nitrogen-containing heterocyclic compound according to claim 4, wherein The molar ratio of the acetaldehyde ammonia trimer to the sulfuryl fluoride is 1:1.0-3.2 or the molar ratio of the acetaldehyde ammonia trimer to the alkenyl sulfonyl fluoride is 1:1.0-3.2, the certain temperature is -20-40°C and the insulation time is 2-3h.

9. A method for preparing an alkali metal salt of a nitrogen-containing heterocyclic compound, characterized in that: Includes steps: (1) mixing acetaldehyde ammonia trimer and a first medium at a certain temperature to form a first solution; (ii) adding sulfuryl fluoride or alkenyl sulfonyl fluoride to the first solution to react and obtain a first product, wherein the alkenyl sulfonyl fluoride is CH2=CH-(CH2) n-1 -SO2F, n is an integer of 1 to 10, the molar ratio of the acetaldehyde ammonia trimer to the sulfuryl fluoride is 1:2.0 to 2.2, or the molar ratio of the acetaldehyde ammonia trimer to the alkenyl sulfonyl fluoride is 1:2.0 to 2.2, (iii) mixing the first product with a third solvent to form a second solution, adding an alkali metal compound to the second solution and adjusting the pH value to react, and purifying the reactant.

10. Use of the nitrogen-containing heterocyclic compound according to any one of claims 1 to 3, the nitrogen-containing heterocyclic compound prepared by the method for preparing the nitrogen-containing heterocyclic compound according to any one of claims 4 to 8, or the alkali metal salt of the nitrogen-containing heterocyclic compound prepared by the method for preparing the alkali metal salt of the nitrogen-containing heterocyclic compound according to claim 9 as an electrolyte additive.

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