Fluorine phosphorus compound, electrolyte, and secondary battery

Abstract

The invention provides a fluorine-phosphorus compound, an electrolyte and a secondary battery. Wherein the structural general formula of the fluorine-phosphorus compound is as follows: # imgabs0; R1, R2, R3 and R4 are independently selected from hydrogen atoms, C1-12 linear saturated alkyl, C1-12 linear unsaturated alkyl, aryl, C1-12 silyl, allyloxy, allyloxyalkyl, acyloxy containing saturated alkyl, acyloxyalkyl containing saturated alkyl and acyloxy containing unsaturated alkyl, and R1, R2, R3 and R4 are independently selected from hydrogen atoms, C1-12 linear saturated alkyl, C1-12 linear unsaturated alkyl, aryl, C1-12 silyl, allyloxy, allyloxyalkyl and acyloxy containing unsaturated alkyl; or one of acyloxy alkyl containing unsaturated alkyl; m < + > is alkali metal ions or quaternary ammonium salt type cations. The fluorine-phosphorus compound provided by the invention can effectively enhance the conductivity of M ions, thereby improving the first coulombic efficiency and cycle performance of the secondary battery under a high-voltage condition.

Description

Technical Field

[0001] The present invention belongs to the technical field of secondary battery electrolytes, and specifically relates to fluorophosphorus compounds, electrolytes, and secondary batteries. Background Art

[0002] With the increasing awareness of environmental protection and the rapid development of the electric vehicle market, the demand for secondary batteries is also continuously growing. As an important component of the battery, the electrolyte of the secondary battery plays a key role in battery performance, safety, and lifespan. According to different composition components and properties, secondary battery electrolytes can be divided into various types.

[0003] Alkali metal salts are the core components of secondary battery electrolytes and determine the electrochemical performance of the battery. Common alkali metal salts include lithium salts or sodium salts, etc. The electrolyte solvent is responsible for transporting ions during battery operation. Common solvents include organic solvents (such as carbonates, propylene carbonate, etc.) and ionic liquids, etc. Additives are used to improve certain properties of the electrolyte, such as increasing ionic conductivity, reducing interfacial tension, etc.

[0004] The chemical composition of the electrolyte has an important impact on the performance of secondary batteries. Alkali metal salts provide ions during the operation of secondary batteries and participate in electrochemical reactions. The electrolyte solvent is responsible for transporting ions and affects the electrochemical performance and safety of the battery. Additives improve the battery performance by improving the properties of the electrolyte. Appropriate electrolyte components can increase the energy density of the battery, improve the cycle life, and enhance the rate performance, etc.

[0005] At the same time, the safety of the electrolyte is also crucial. The chemical properties of the electrolyte are closely related to the safety of the battery, such as redox stability, flash point, boiling point, etc. Therefore, when selecting an electrolyte, it is necessary to comprehensively consider its performance and safety.

[0006] A suitable electrolyte can enhance various performances of the battery, including energy density, charge-discharge efficiency, and cycle life, while ensuring the safety of the battery. In the development of secondary batteries, improving energy density is one of the important directions. Whether in small energy storage devices or electric vehicle applications, smaller and lighter batteries are the hotspots in the market. The energy density of secondary batteries can be increased by raising the charging voltage of the battery cathode material. However, while increasing the voltage of the cathode material, the performances such as charge-discharge cycles of the battery decline, and high-voltage electrolytes are one of the key factors. At high voltages (≥4.35V vs Li / Li), the oxidation activity of the cathode material increases, resulting in the oxidation reaction of the electrolyte on the electrode surface, causing an increase in the irreversible capacity of the secondary battery, a decrease in the first Coulombic efficiency of the battery, a reduction in the utilization rate of the cathode material, and a decrease in the battery capacity. Therefore, it is necessary to develop an electrolyte that can withstand high voltages to enable the secondary battery to achieve a high first Coulombic efficiency and good cycle performance at high voltages. Summary of the Invention

[0007] Technical problems to be solved: Aiming at the above technical problems, the present invention provides a fluorophosphorus compound. When applied to an electrolyte and a secondary battery, it can increase the energy density of the secondary battery.

[0008] Technical solutions:

[0009] In the first aspect, the present invention provides a fluorophosphorus compound, including the following structural formulas I and II:

[0010]

[0011] Among them, R1, R2, R3, and R4 are independently selected from a hydrogen atom, C 1-12 linear saturated hydrocarbon group, C 1-12 linear unsaturated hydrocarbon group, aromatic group, C 1-12 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing a saturated hydrocarbon group, acyloxyalkyl group containing a saturated hydrocarbon group, acyloxy group containing an unsaturated hydrocarbon group, or acyloxyalkyl group containing an unsaturated hydrocarbon group; among them, C 1-12 linear saturated hydrocarbon group, C 1-12 linear unsaturated hydrocarbon group, aromatic group, C 1-12 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing a saturated hydrocarbon group, acyloxyalkyl group containing a saturated hydrocarbon group, acyloxy group containing an unsaturated hydrocarbon group, and acyloxyalkyl group containing an unsaturated hydrocarbon group are each independently unsubstituted, or substituted by a halogen element or a phenyl group; the M + is an alkali metal ion or a quaternary ammonium salt type cation.

[0012] One of the preferred solutions is that R1, R2, R3, and R4 are independently selected from a hydrogen atom, C 1-6 linear saturated hydrocarbon group, C 1-6a linear unsaturated hydrocarbon group, an aromatic group, C 1-6 a silyl group, an allyloxy group, an allyloxyalkyl group, an acyloxy group containing a saturated hydrocarbon group, an acyloxyalkyl group containing a saturated hydrocarbon group, an acyloxy group containing an unsaturated hydrocarbon group, or an acyloxyalkyl group containing an unsaturated hydrocarbon group; wherein, C 1-6 a linear saturated hydrocarbon group, C 1-6 a linear unsaturated hydrocarbon group, an aromatic group, C 1-6 the silyl group, the allyloxy group, the allyloxyalkyl group, the acyloxy group containing a saturated hydrocarbon group, the acyloxyalkyl group containing a saturated hydrocarbon group, the acyloxy group containing an unsaturated hydrocarbon group, and the acyloxyalkyl group containing an unsaturated hydrocarbon group are each independently unsubstituted or substituted by a halogen element or a phenyl group;

[0013] One of the preferred embodiments, the alkali metal ion is Li + 、Na + or K + .

[0014] One of the preferred embodiments, the quaternary ammonium salt type cation is a tetramethylammonium ion or a tetrabutylammonium ion.

[0015] One of the second preferred embodiments, the R1, R2, R3, and R4 are independently selected from a hydrogen atom, C 1-4 a linear alkyl group, C 1-4 a linear alkenyl group, C 1-4 a linear alkynyl group, an aromatic group, C 1-4 a silyl group, an allyloxy group, an allyloxyalkyl group, an acyloxy group containing a saturated hydrocarbon group, an acyloxyalkyl group containing a saturated hydrocarbon group, an acyloxy group containing an unsaturated hydrocarbon group, or an acyloxyalkyl group containing an unsaturated hydrocarbon group; wherein, C 1-4 the linear alkyl group, C 1-4 the linear alkenyl group, C 1-4 the linear alkynyl group, an aromatic group, C 1-4 the silyl group, the allyloxy group, the allyloxyalkyl group, the acyloxy group containing a saturated hydrocarbon group, the acyloxyalkyl group containing a saturated hydrocarbon group, the acyloxy group containing an unsaturated hydrocarbon group, and the acyloxyalkyl group containing an unsaturated hydrocarbon group are each independently unsubstituted or substituted by a halogen element or a phenyl group.

[0016] One of the third preferred embodiments, the R1, R2, R3, and R4 are independently selected from a hydrogen atom, a methyl group, an ethyl group, a propyl group, an allyloxy group, an allyloxymethyl group, an acryloxy group, an acryloxymethyl group, a methacryloxy group, a methacryloxymethyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, a vinyl group, an allyl group, an isopropyl group, a crotyl group, an isocrotyl group, a cyclopentadienyl group, a pentadienyl group, an ethynyl group, a pentynyl group, a phenyl group, a benzyl group, a phenethyl group, a trimethylsilyl group, a triethylsilyl group, a tert-butyldimethylsilyl group, a tert-butyldiphenylsilyl group, a diisopropylsilyl group, a diphenylsilyl group, or a diisopropylphenethylsilyl group.

[0017] The fourth preferred solution: The above-mentioned fluorophosphorus compound has the following specific structure:

[0018]

[0019]

[0020] Furthermore, the above-mentioned fluorophosphorus compound is obtained by reacting a main raw material with hexafluorophosphate; the structural formula of the main raw material is

[0021]

[0022] wherein, R1 and R2 are independently selected from a hydrogen atom, C 1-12 linear saturated hydrocarbon group, C 1-12 linear unsaturated hydrocarbon group, aromatic group, C 1-12 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing a saturated hydrocarbon group, acyloxyalkyl group containing a saturated hydrocarbon group, acyloxy group containing an unsaturated hydrocarbon group, or acyloxyalkyl group containing an unsaturated hydrocarbon group; wherein, C 1-12 linear saturated hydrocarbon group, C 1-12 linear unsaturated hydrocarbon group, aromatic group, C 1-12 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing a saturated hydrocarbon group, acyloxyalkyl group containing a saturated hydrocarbon group, acyloxy group containing an unsaturated hydrocarbon group, and acyloxyalkyl group containing an unsaturated hydrocarbon group are each independently unsubstituted or substituted by a halogen element or a phenyl group.

[0023] In the second aspect, the present invention provides an electrolyte containing the above-mentioned fluorophosphorus compound.

[0024] Furthermore, the above-mentioned electrolyte further includes an alkali metal salt and an aprotic solvent.

[0025] Preferably, the alkali metal salt includes a lithium salt and / or a sodium salt.

[0026] Preferably, the lithium salt is at least one of lithium hexafluorophosphate, lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium difluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, or lithium bis(fluorosulfonyl)imide.

[0027] Preferably, the sodium salt is at least one of sodium hexafluorophosphate, sodium bis(oxalato)borate, sodium difluoro(oxalato)borate, sodium difluorophosphate, sodium bis(trifluoromethanesulfonyl)imide, or sodium bis(fluorosulfonyl)imide.

[0028] Preferably, the aprotic solvent is at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl acetate, methyl propionate, ethyl propionate, or propyl propionate.

[0029] Preferably, the mass concentration of the fluorophosphorus compound in the electrolyte is 0.5-28%; the molar concentration of the alkali metal salt in the electrolyte is 0.5-3 mol / L.

[0030] Furthermore, the above electrolyte further includes fluoroethylene carbonate; preferably, the mass concentration of fluoroethylene carbonate in the electrolyte is 1-8%.

[0031] In a third aspect, the present invention also provides a secondary battery, comprising the above-mentioned fluorophosphorus compound; and / or comprising the above-mentioned electrolyte.

[0032] Beneficial effects: The present invention provides a fluorophosphorus compound, which can be used as an electrolyte additive, increasing the ion concentration in the electrolyte. The M ions in the electrolyte can enhance the conductivity of the electrolyte. After adding this type of additive, it can inhibit the large internal resistance during high-voltage charge and discharge of the battery and improve the stability of the electrode material, thereby improving the first Coulomb efficiency and cycling performance of the secondary battery under high-voltage conditions. The electrolyte provided by the present invention has a significant improvement effect on the first Coulomb efficiency and cycling performance of various lithium-ion and sodium-ion battery systems under high voltage. Specific embodiments

[0033] The present invention will be specifically described below through examples. The examples give detailed implementation methods and specific operation steps, which are only used for further illustration of the present invention and cannot be construed as limiting the protection scope of the present invention.

[0034] Preparation example 1 of the main raw material

[0035] Main raw material 1 is used as the main raw material in Examples 1-3 and 13-15. The preparation method of main raw material 1:

[0036]

[0037] (1) Add 13.3 grams (151.0 mmol) of dried butanediol, 35.6 grams (351.8 mmol) of triethylamine, and 150 mL of n-hexane into a 250 mL three-necked reaction flask. Replace with nitrogen three times to ensure there is no air in the reaction flask. Keep stirring and cool down with an ice-water bath. Slowly drop 32.8 grams (302.0 mmol) of trimethylchlorosilane under the condition of the ice-water bath. After dropping, stir and react at room temperature for 1 hour, then heat to 60 °C and react for 24 hours.

[0038] (2) The next day, a large amount of white solid is produced in the reaction flask. Cool down to about 0 °C with an ice-water bath, filter, wash the filter cake with 50 mL of n-hexane, combine the filtrates, concentrate and remove the solvent with a rotary evaporator, and then distill under vacuum with an oil pump to receive the main fraction to obtain main raw material 1.

[0039] Preparation Example 2 of the Main Raw Material

[0040] The main raw material 2 is used as the main raw material in Examples 4-6 and 16-18. The preparation method of the main raw material 2 is as follows:

[0041]

[0042] (1) Add 100 g (1.08 mol) of glycerol to a 500 mL three-necked flask, add 100 mL of ethyl acetate, stir evenly, add 3-5 drops of concentrated sulfuric acid, slowly heat up to 60 °C, control the temperature at 60-70 °C and dropwise add 58 g (1 mol) of allyl alcohol. After the addition is complete, keep the temperature at 60-70 °C and react for 3 h. Stop the reaction and concentrate the reaction solution to obtain about 140 g of S1.

[0043]

[0044] (2) Add the 140 g (1 mol) of S1 obtained by concentration to 300 mL of tetrahydrofuran, stir and mix evenly, then concentrate with a rotary evaporator at a bath temperature of 50 °C and a vacuum degree of -0.09 Mpa to remove the solvent tetrahydrofuran and a small amount of water to obtain dried S1. Then add the dried S1, 252 g (2.5 mo1) of triethylamine and 600 mL of n-hexane to a 2000 mL three-necked reaction flask, displace with nitrogen three times to ensure that there is no air in the reaction flask, keep stirring, cool down with an ice-water bath, and slowly dropwise add 216 g (2 mo1) of trimethylchlorosilane under the condition of the ice-water bath. After the addition is complete, stir and react at room temperature (since this reaction is an exothermic reaction, the temperature of the reaction solution will rise during the reaction) for 1 h, and then heat to 60 °C and react for 24 h.

[0045] (3) The next day, a large amount of white solid is produced in the reaction flask. Cool down to about 0 °C with an ice-water bath, filter, wash the filter cake with 300 mL of n-hexane, combine the filtrates, concentrate to remove the solvent with a rotary evaporator, and then distill under vacuum with an oil pump to collect the main fraction to obtain the main raw material 2.

[0046] Preparation Example 3 of the Main Raw Material

[0047] The main raw material 3 is used as the main raw material in Examples 7-9 and 19-21. The preparation method of the main raw material 3 is as follows:

[0048]

[0049] (1) Add 50 g (0.54 mol) of glycerol to a 500 mL three-necked flask, add 100 mL of ethyl acetate, stir evenly, add 3-5 drops of concentrated sulfuric acid, slowly heat up to 60 °C, control the temperature at 60-70 °C and dropwise add 36 g (0.5 mol) of acrylic acid. After the addition is complete, keep the temperature at 60-70 °C and react for 3 h. Stop the reaction and concentrate the reaction solution to obtain about 76 g of S2.

[0050]

[0051] (2) Add 76 g (0.5 mol) of S2 obtained by concentration to 150 mL of tetrahydrofuran, stir and mix evenly, then concentrate with a rotary evaporator at a bath temperature of 50 °C and a vacuum degree of -0.09 Mpa to remove the solvent tetrahydrofuran and a small amount of water, obtaining dried S2. Then add the dried S2, 126 g (1.25 mo1) of triethylamine and 300 mL of n-hexane to a 1000 mL three-necked reaction flask, displace with nitrogen three times to ensure there is no air in the reaction flask, keep stirring, cool with an ice-water bath, and slowly drop 108 g (1 mo1) of trimethylchlorosilane under the condition of the ice-water bath. After dropping, stir and react at room temperature (since this reaction is an exothermic reaction, the temperature of the reaction solution will rise during the reaction) for 1 hour, and then heat to 60 °C and react for 24 hours.

[0052] (3) The next day, a large amount of white solid is produced in the reaction flask. Cool it to about 0 °C with an ice-water bath, filter, wash the filter cake with 300 mL of n-hexane, combine the filtrates, concentrate to remove the solvent with a rotary evaporator, and then distill under vacuum with an oil pump to collect the main fraction, obtaining the main raw material 3.

[0053] Preparation Example 4 of the Main Raw Material

[0054] The main raw material 4 is used as the main raw material in Examples 10 - 12 and 22 - 24. The preparation method of the main raw material 4:

[0055]

[0056] (1) Add 50 g (0.54 mol) of glycerol to a 500 mL three-necked flask, add 100 mL of ethyl acetate, stir evenly, add 3 - 5 drops of concentrated sulfuric acid, slowly heat to 60 °C, control the temperature at 60 - 70 °C and drop 43 g (0.5 mol) of 2-methylacrylic acid. After dropping, keep the temperature at 60 - 70 °C and react for 3 h, then stop the reaction, and concentrate the reaction solution to obtain about 82 g of S3.

[0057]

[0058] (2) Add 82 g (0.5 mol) of S3 obtained by concentration to 150 mL of tetrahydrofuran, stir and mix evenly, then concentrate it using a rotary evaporator at a bath temperature of 50 °C and a vacuum degree of -0.09 Mpa to remove the solvent tetrahydrofuran and a small amount of water, obtaining dried S3. Then add the dried S3, 126 g (1.25 mo1) of triethylamine, and 300 mL of n-hexane to a 1000 mL three-neck reaction flask, displace with nitrogen three times to ensure there is no air in the reaction flask, maintain the stirring state, cool down with an ice-water bath, and slowly drop 108 g (1 mo1) of trimethylchlorosilane under the condition of the ice-water bath. After dropping, stir and react at room temperature (since this reaction is an exothermic reaction, the temperature of the reaction solution will rise during the reaction) for 1 hour, and then heat to 60 °C and react for 24 hours.

[0059] (3) The next day, a large amount of white solid is produced in the reaction flask. Cool it down to about 0 °C with an ice-water bath, filter, wash the filter cake with 300 mL of n-hexane, combine the filtrates, concentrate and remove the solvent using a rotary evaporator, and then distill under vacuum with an oil pump to collect the main fraction, obtaining the main raw material 4.

[0060] Example 1

[0061] Preparation of fluorophosphorus compound No. 1:

[0062] The synthesis route is as follows:

[0063]

[0064] (1) Dissolve 23.2 g of dry main raw material 1 in 70 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-neck flask equipped with a thermometer, first add 45 mL of EMC, and then add 15.2 g of lithium hexafluorophosphate while shaking. After adding, a second mixed solution is obtained; the molar ratio of dry main raw material 1 to lithium hexafluorophosphate is 1:1.

[0065] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, drop the first mixed solution into the second mixed solution. After dropping, continue to stir and react at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the obtained turbid liquid after the reaction to obtain a small amount of insoluble substances, remove the solvent under reduced pressure from the filtrate, add 25 mL of toluene and stir at room temperature to precipitate a large amount of white solid. Filter, wash, and dry to obtain 17.2 g of white solid, which is fluorophosphorus compound No. 1.

[0066] The 1H NMR spectrum data of compound 1 was measured using a Thermo Fisher nuclear magnetic resonance spectrometer (model picoSpin 45) as follows:

[0067] 1H-NMR (400 MHz, CDCl3) δ 3.48 - 3.52 (d, 2H), 4.16 - 4.19 (m, 1H), 5.12 - 5.14 (d, 1H), 5.24 - 5.30 (d, 1H), 5.84 - 5.89 (m, 1H).

[0068] The purity was determined to be 99.7% by Thermo Fisher ion chromatograph (model ICS-600), with water content of 52 ppm and acid value of 65 ppm.

[0069] Elemental analysis was performed using a Thermo Fisher organic elemental analyzer (model FlashSmart), and the following results were obtained:

[0070] Element C H O P F Li Element content % 24.05 3.02 15.92 15.49 38.12 3.40

[0071] Note: In Examples 1 - 24 of this application, the purity, water content, and acid value were determined using a Thermo Fisher ion chromatograph (model ICS-600). In Examples 1 - 24 of this application, elemental analysis was performed using a Thermo Fisher organic elemental analyzer (model FlashSmart).

[0072] Example 2

[0073] Preparation of fluorophosphorus compound No. 2:

[0074] The synthesis route is as follows:

[0075]

[0076] (1) Dissolve 11.6 g of dry main raw material 1 in 50 mL of EMC to prepare a first mixed solution for later use. In a 500 mL three-necked flask equipped with a thermometer, first add 55 mL of EMC, then add 8.4 g of sodium hexafluorophosphate, and shake while adding. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 1 to sodium hexafluorophosphate is 1:1.

[0077] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue stirring and reacting at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent under reduced pressure from the filtrate, add 20 mL of toluene, stir at room temperature, and a large amount of white solid precipitates. Filter, wash, and dry to obtain 9.4 g of white solid, which is fluorophosphorus compound No. 2.

[0078] The purity was determined to be 99.4% by ion chromatography, with water content of 50 ppm and acid value of 54 ppm.

[0079] After elemental analysis:

[0080] Element C H O P F Na Element content % 22.25 2.83 14.85 14.27 35.19 10.61

[0081] Example 3

[0082] Preparation of fluorophosphorus compound No. 3:

[0083] The synthesis route is as follows:

[0084]

[0085] (1) Dissolve 23.2 g of dry main raw material 1 in 60 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 18.4 g of potassium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 1 to potassium hexafluorophosphate is 1:1;

[0086] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue to stir and react at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the obtained turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent under reduced pressure from the filtrate, add 40 mL of toluene and stir at room temperature to precipitate a large amount of white solid. Filter, wash, and dry to obtain 19.6 g of white solid, which is fluorophosphorus compound No. 3.

[0087] The purity measured by ion chromatography is 99.3%, the water content is 51 ppm, and the acid value is 63 ppm.

[0088] After elemental analysis:

[0089] Element C H O P F K Element content % 20.65 2.64 13.75 13.37 32.72 16.87

[0090] Example 4

[0091] Preparation of fluorophosphorus compound No. 4:

[0092] The synthesis route is as follows:

[0093]

[0094] (1) Dissolve 27.6 g of dry main raw material 2 in 120 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 80 mL of EMC, and then add 15.2 g of lithium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 2 to lithium hexafluorophosphate is 1:1;

[0095] (2) Heat the second mixed solution to 50 °C under a nitrogen atmosphere, add the first mixed solution dropwise to the second mixed solution. After the addition is complete, continue stirring and reacting at 50 °C until there is basically no gas generation in the tail gas absorption solution. Cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 50 mL of toluene and stir at room temperature to precipitate a large amount of white solid. Filter, wash, and dry to obtain 21.1 g of white solid, which is fluorophosphorus compound No. 4.

[0096] The purity was determined by ion chromatography to be 98.3%, the water content was 77 ppm, and the acid value was 84 ppm.

[0097] After elemental analysis:

[0098] Element C H O P F Li Element content % 29.47 4.07 19.71 12.72 31.14 2.89

[0099] Example 5

[0100] Preparation of fluorophosphorus compound No. 5:

[0101] The synthesis route is as follows:

[0102]

[0103] (1) Dissolve 27.6 g of dry main raw material 2 in 120 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 80 mL of EMC, then add 16.8 g of sodium hexafluorophosphate, and shake while adding. After the addition is complete, obtain a second mixed solution. The molar ratio of dry main raw material 2 to sodium hexafluorophosphate is 1:1.

[0104] (2) Heat the second mixed solution to 50 °C under a nitrogen atmosphere, add the first mixed solution dropwise to the second mixed solution. After the addition is complete, continue stirring and reacting at 50 °C until there is basically no gas generation in the tail gas absorption solution. Cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 50 mL of toluene and stir at room temperature to precipitate a large amount of white solid. Filter, wash, and dry to obtain 21.3 g of white solid, which is fluorophosphorus compound No. 5.

[0105] The purity was determined by ion chromatography to be 99.5%, the water content was 64 ppm, and the acid value was 74 ppm.

[0106] After elemental analysis:

[0107] Element C H O P F Na Element content % 27.65 3.85 18.44 11.92 29.21 8.93

[0108] Example 6

[0109] Preparation of fluorophosphorus compound No. 6:

[0110] The synthesis route is as follows:

[0111]

[0112] (1) Dissolve 27.6 g of dry main raw material 2 in 120 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 80 mL of EMC, then add 18.4 g of potassium hexafluorophosphate, and shake while adding. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 2 to potassium hexafluorophosphate is 1:1;

[0113] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue stirring and reacting at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 50 mL of toluene and stir at room temperature to precipitate a large amount of white solid. Filter, wash, and dry to obtain 21.8 g of white solid, which is fluorophosphorus compound No. 6.

[0114] The purity was determined by ion chromatography to be 99.3%, the water content was 62 ppm, and the acid value was 73 ppm.

[0115] After elemental analysis:

[0116] Element C H O P F K Element content % 26.09 3.65 17.42 11.18 27.55 14.11

[0117] Example 7

[0118] Preparation of fluorophosphorus compound No. 7:

[0119] The synthesis route is as follows:

[0120]

[0121] (1) Dissolve 29 g of dry main raw material 3 in 120 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 80 mL of EMC, then add 15.2 g of lithium hexafluorophosphate, and shake while adding. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 3 to lithium hexafluorophosphate is 1:1;

[0122] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue stirring and reacting at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 50 mL of toluene and stir at room temperature to precipitate a large amount of white solid. Filter, wash, and dry to obtain 21.3 g of white solid, which is fluorophosphorus compound No. 7.

[0123] The purity was determined by ion chromatography to be 99.2%, the water content was 73 ppm, and the acid value was 71 ppm.

[0124] After elemental analysis:

[0125] Element C H O P F Li Element content % 27.92 3.08 24.84 11.98 29.48 2.70

[0126] Example 8

[0127] Preparation of fluorophosphorus compound No. 8:

[0128] The synthesis route is as follows:

[0129]

[0130] (1) Dissolve 29 g of dry main raw material 3 in 120 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 80 mL of EMC, and then add 16.8 g of sodium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 3 to sodium hexafluorophosphate is 1:1;

[0131] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue to stir and react at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the obtained turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent under reduced pressure from the filtrate, add 50 mL of toluene and stir at room temperature to precipitate a large amount of white solid. Filter, wash, and dry to obtain 21.4 g of white solid, which is fluorophosphorus compound No. 8.

[0132] The purity measured by ion chromatography is 99.7%, the water content is 61 ppm, and the acid value is 72 ppm.

[0133] After elemental analysis:

[0134] Element C H O P F Na Element content % 26.29 2.87 23.36 11.32 27.74 8.42

[0135] Example 9

[0136] Preparation of fluorophosphorus compound No. 9:

[0137] The synthesis route is as follows:

[0138]

[0139] (1) Dissolve 29 g of dry main raw material 3 in 120 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 80 mL of EMC, and then add 18.4 g of potassium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 3 to potassium hexafluorophosphate is 1:1;

[0140] (2) Heat the second mixture to 50 °C under a nitrogen atmosphere, add the first mixture dropwise to the second mixture. After the addition is complete, continue stirring the reaction at 50 °C until there is basically no gas generation in the tail gas absorption liquid; cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 50 mL of toluene and stir at room temperature to precipitate a large amount of white solid. Filter, wash, and dry to obtain 24.1 g of white solid, which is fluorophosphorus compound No. 9.

[0141] The purity was determined by ion chromatography to be 98.9%, the water content was 60 ppm, and the acid value was 72 ppm.

[0142] After elemental analysis:

[0143] Element C H O P F K Element content % 24.82 2.78 22.09 10.64 26.19 13.48

[0144] Example 10

[0145] Preparation of fluorophosphorus compound No. 10:

[0146] The synthesis route is as follows:

[0147]

[0148] (1) Dissolve 30.5 g of dry main raw material 4 in 120 mL of EMC to prepare a first mixture for use. In a 500 mL three-necked flask equipped with a thermometer, first add 80 mL of EMC, and then add 15.2 g of lithium hexafluorophosphate while shaking. After the addition is complete, a second mixture is obtained; the molar ratio of dry main raw material 4 to lithium hexafluorophosphate is 1:1;

[0149] (2) Heat the second mixture to 50 °C under a nitrogen atmosphere, add the first mixture dropwise to the second mixture. After the addition is complete, continue stirring the reaction at 50 °C until there is basically no gas generation in the tail gas absorption liquid; cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 50 mL of toluene and stir at room temperature to precipitate a large amount of white solid. Filter, wash, and dry to obtain 23.9 g of white solid, which is fluorophosphorus compound No. 10.

[0150] The purity was determined by ion chromatography to be 99.5%, the water content was 45 ppm, and the acid value was 66 ppm.

[0151] After elemental analysis:

[0152] Element C H O P F Li Element content % 30.86 3.68 23.53 11.35 27.98 2.60

[0153] Example 11

[0154] Preparation of fluorophosphorus compound No. 11:

[0155] The synthesis route is as follows:

[0156]

[0157] (1) Dissolve 30.5 g of dry main raw material 4 in 120 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 80 mL of EMC, then add 16.8 g of sodium hexafluorophosphate, and shake while adding. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 4 to sodium hexafluorophosphate is 1:1;

[0158] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the dropping is complete, continue stirring and reacting at 50 °C until there is basically no gas generation in the tail gas absorption solution; cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble substances. Remove the solvent from the filtrate under reduced pressure, add 50 mL of toluene, stir at room temperature, a large amount of white solid precipitates, filter, wash, and dry to obtain 24.2 g of white solid, which is fluorophosphorus compound No. 11.

[0159] The purity is determined by ion chromatography to be 99.6%, the water content is 64 ppm, and the acid value is 62 ppm.

[0160] After elemental analysis:

[0161] Element C H O P F Na Element content % 29.18 3.51 22.23 10.68 26.41 7.99

[0162] Example 12

[0163] Preparation of fluorophosphorus compound No. 12:

[0164] The synthesis route is as follows:

[0165]

[0166] (1) Dissolve 30.5 g of dry main raw material 4 in 120 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 80 mL of EMC, then add 18.4 g of potassium hexafluorophosphate, and shake while adding. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 4 to potassium hexafluorophosphate is 1:1;

[0167] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the dropping is complete, continue stirring and reacting at 50 °C until there is basically no gas generation in the tail gas absorption solution; cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble substances. Remove the solvent from the filtrate under reduced pressure, add 50 mL of toluene, stir at room temperature, a large amount of white solid precipitates, filter, wash, and dry to obtain 23.1 g of white solid, which is fluorophosphorus compound No. 12.

[0168] The purity is determined to be 99.8%, the water content is 53 ppm, and the acid value is 57 ppm by ion chromatography.

[0169] After elemental analysis:

[0170] Element C H O P F K Element content % 27.64 3.29 21.06 10.15 25.01 12.85

[0171] Example 13

[0172] Preparation of fluorophosphorus compound No. 13:

[0173] The synthesis route is as follows:

[0174]

[0175] (1) Dissolve 46.4 g of dry main raw material 1 in 140 mL of EMC to prepare a first mixed solution for later use. In a 1 L three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 15.2 g of lithium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 1 to lithium hexafluorophosphate is 2:1.

[0176] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue to stir and react at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the turbid liquid obtained after the reaction to remove a small amount of insoluble substances. Remove the solvent under reduced pressure from the filtrate, add 52 mL of toluene, and stir at room temperature to precipitate a large amount of white solid. After filtration, washing, and drying, 26.3 g of white solid is obtained, which is fluorophosphorus compound No. 13.

[0177] The 1H-NMR spectrum data of fluorophosphorus compound No. 1 was measured using a Thermo Fisher nuclear magnetic resonance spectrometer (model picoSpin 45) as follows: 1H-NMR (400 MHz, CDCl3) 3.49 - 3.54 (d, 2H), 4.17 - 4.19 (m, 1H), 5.13 - 5.16 (d, 1H), 5.23 - 5.30 (d, 1H), 5.83 - 5.88 (m, 1H).

[0178] The purity is determined to be 98.8%, the water content is 46 ppm, and the acid value is 55 ppm by using a Thermo Fisher ion chromatograph (model ICS-600).

[0179] Elemental analysis was carried out using a Thermo Fisher organic elemental analyzer (model FlashSmart), and the following results were obtained:

[0180] Element C H O P F Li Element content % 38.65 4.87 25.72 12.45 15.46 2.85

[0181] Example 14

[0182] Preparation of fluorophosphorus compound No. 14:

[0183] The synthetic route is as follows:

[0184]

[0185] (1) Dissolve 23.2 g of dry main raw material 1 in 180 mL of EMC to prepare a first mixed solution for use. In a 1 L three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 8.4 g of sodium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained. The molar ratio of dry main raw material 1 to sodium hexafluorophosphate is 2:1;

[0186] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue to stir and react at 50 °C until there is basically no gas generated in the tail gas absorption solution. Cool and filter the obtained turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 52 mL of toluene and stir at room temperature to precipitate a large amount of white solid. After filtration, washing and drying, 10.7 g of white solid is obtained, which is fluorophosphorus compound No. 14.

[0187] The measured purity is 98.5%, the moisture content is 55 ppm, and the acid value is 62 ppm.

[0188] After elemental analysis:

[0189] Element C H O P F Na Element content % 36.37 4.53 24.28 11.65 14.45 8.72

[0190] Example 15

[0191] Preparation of fluorophosphorus compound No. 15:

[0192] The synthetic route is as follows:

[0193]

[0194] (1) Dissolve 23.2 g of dry main raw material 1 in 60 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 40 mL of EMC, and then add 9.2 g of potassium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained. The molar ratio of dry main raw material 1 to potassium hexafluorophosphate is 2:1;

[0195] (3) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue to stir and react at 50 °C until there is basically no gas generated in the tail gas absorption solution. Cool and filter the obtained turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 25 mL of toluene and stir at room temperature to precipitate a large amount of white solid. After filtration, washing and drying, 11.2 g of white solid is obtained, which is fluorophosphorus compound No. 15.

[0196] The purity was determined by ion chromatography to be 99.5%, the water content was 55 ppm, and the acid value was 68 ppm.

[0197] After elemental analysis:

[0198] Element C H O P F K Element content % 34.32 4.29 22.87 11.08 13.49 13.95

[0199] Example 16

[0200] Preparation of fluorophosphorus compound No. 16:

[0201] The synthesis route is as follows:

[0202]

[0203] (1) Dissolve 27.6 g of dry main raw material 2 in 80 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 7.6 g of lithium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 2 to lithium hexafluorophosphate is 2:1;

[0204] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue to stir and react at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent under reduced pressure from the filtrate, add 25 mL of toluene, stir at room temperature, a large amount of white solid precipitates, and after filtration, washing and drying, 13.4 g of white solid is obtained, which is fluorophosphorus compound No. 16.

[0205] The measured purity was 99.1%, the water content was 67 ppm, and the acid value was 73 ppm.

[0206] After elemental analysis:

[0207] Element C H O P F Li Element content % 42.86 5.95 28.53 9.25 11.28 2.13

[0208] Example 17

[0209] Preparation of fluorophosphorus compound No. 17:

[0210] The synthesis route is as follows:

[0211]

[0212] (1) Dissolve 27.6 g of dry main raw material 2 in 80 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 8.4 g of sodium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 2 to sodium hexafluorophosphate is 2:1;

[0213] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, add the first mixed solution dropwise to the second mixed solution. After the addition is complete, continue stirring and reacting at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the obtained turbid liquid after the reaction to obtain a small amount of insoluble substances. Remove the solvent from the filtrate under reduced pressure, add 25 mL of toluene and stir at room temperature to precipitate a large amount of white solid. After filtration, washing and drying, 13.4 g of white solid is obtained, which is fluorophosphorus compound No. 17.

[0214] The measured purity is 99.3%, the moisture content is 62 ppm, and the acid value is 74 ppm.

[0215] After elemental analysis:

[0216] Element C H O P F Na Element content % 40.89 5.65 27.28 8.75 10.79 6.64

[0217] Example 18

[0218] Preparation of fluorophosphorus compound No. 18:

[0219] The synthesis route is as follows:

[0220]

[0221] (1) Dissolve 27.6 g of dry main raw material 2 in 80 mL of EMC to prepare the first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 9.2 g of potassium hexafluorophosphate while shaking. After the addition is complete, the second mixed solution is obtained; the molar ratio of dry main raw material 2 to potassium hexafluorophosphate is 2:1;

[0222] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, add the first mixed solution dropwise to the second mixed solution. After the addition is complete, continue stirring and reacting at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the obtained turbid liquid after the reaction to obtain a small amount of insoluble substances. Remove the solvent from the filtrate under reduced pressure, add 25 mL of toluene and stir at room temperature to precipitate a large amount of white solid. After filtration, washing and drying, 13.9 g of white solid is obtained, which is fluorophosphorus compound No. 18.

[0223] The measured purity is 99.3%, the moisture content is 61 ppm, and the acid value is 71 ppm.

[0224] After elemental analysis:

[0225] Element C H O P F K Element content % 39.07 5.43 26.03 8.41 10.35 10.71

[0226] Example 19

[0227] Preparation of fluorophosphorus compound No. 19:

[0228] The synthesis route is as follows:

[0229]

[0230] (1) Dissolve 29 g of dry main raw material 3 in 80 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 7.6 g of lithium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 3 to lithium hexafluorophosphate is 2:1;

[0231] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the dropping is complete, continue stirring and reacting at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the turbid liquid obtained after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 25 mL of toluene and stir at room temperature to precipitate a large amount of white solid. After filtration, washing and drying, 13.4 g of white solid is obtained, which is fluorophosphorus compound No. 19.

[0232] The measured purity is 99.4%, the moisture content is 77 ppm, and the acid value is 74 ppm.

[0233] After elemental analysis:

[0234]

[0235]

[0236] Example 20

[0237] Preparation of fluorophosphorus compound No. 20:

[0238]

[0239] (1) Dissolve 29 g of dry main raw material 3 in 80 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 8.4 g of sodium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 3 to sodium hexafluorophosphate is 2:1;

[0240] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the dropping is complete, continue stirring and reacting at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the turbid liquid obtained after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 25 mL of toluene and stir at room temperature to precipitate a large amount of white solid. After filtration, washing and drying, 13.4 g of white solid is obtained, which is fluorophosphorus compound No. 20.

[0241] The measured purity is 99.1%, the moisture content is 72 ppm, and the acid value is 75 ppm.

[0242] After elemental analysis:

[0243] Element C H O P F Na Element content % 37.85 4.18 33.69 8.16 9.99 6.18

[0244] Example 21

[0245] Preparation of fluorophosphorus compound No. 21:

[0246]

[0247] (1) Dissolve 29 g of dry main raw material 3 in 80 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 9.2 g of potassium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 3 to potassium hexafluorophosphate is 2:1;

[0248] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue stirring and reacting at 50 °C until there is basically no gas generated in the tail gas absorption solution; cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent under reduced pressure from the filtrate, add 25 mL of toluene and stir at room temperature to precipitate a large amount of white solid. After filtration, washing and drying, 13.4 g of white solid is obtained, which is fluorophosphorus compound No. 21.

[0249] The measured purity is 99.1%, the moisture content is 73 ppm, and the acid value is 74 ppm.

[0250] After elemental analysis:

[0251] Element C H O P F K Element content % 36.35 4.05 32.25 7.83 9.62 9.90

[0252] Example 22

[0253] Preparation of fluorophosphorus compound No. 22:

[0254]

[0255] (1) Dissolve 30.5 g of dry main raw material 4 in 80 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 7.6 g of lithium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 4 to lithium hexafluorophosphate is 2:1;

[0256] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, add the first mixed solution dropwise to the second mixed solution. After the addition is complete, continue stirring and reacting at 50 °C until there is basically no gas generation in the tail gas absorption solution; cool and filter the obtained turbid liquid after the reaction to obtain a small amount of insoluble substances. Remove the solvent from the filtrate under reduced pressure, add 25 mL of toluene and stir at room temperature to precipitate a large amount of white solid. After filtration, washing, and drying, 18.4 g of white solid is obtained, which is fluorophosphorus compound No. 22.

[0257] The measured purity is 99.3%, the water content is 71 ppm, and the acid value is 62 ppm.

[0258] After elemental analysis:

[0259] Element C H O P F Li Element content % 42.86 5.12 32.65 7.92 9.61 1.84

[0260] Example 23

[0261] Preparation of fluorophosphorus compound No. 23:

[0262]

[0263] (1) Dissolve 30.5 g of dry main raw material 4 in 80 mL of EMC to prepare a first mixed solution for use. In a 500 mL three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 8.4 g of sodium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained; the molar ratio of dry main raw material 4 to sodium hexafluorophosphate is 2:1;

[0264] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, add the first mixed solution dropwise to the second mixed solution. After the addition is complete, continue stirring and reacting at 50 °C until there is basically no gas generation in the tail gas absorption solution; cool and filter the obtained turbid liquid after the reaction to obtain a small amount of insoluble substances. Remove the solvent from the filtrate under reduced pressure, add 25 mL of toluene and stir at room temperature to precipitate a large amount of white solid. After filtration, washing, and drying, 19.2 g of white solid is obtained, which is fluorophosphorus compound No. 23.

[0265] The measured purity is 99.2%, the water content is 61 ppm, and the acid value is 60 ppm.

[0266] After elemental analysis:

[0267] Element C H O P F Na Element content % 41.17 4.92 31.32 7.61 9.31 5.67

[0268] Example 24

[0269] Preparation of fluorophosphorus compound No. 24:

[0270]

[0271] (1) Dissolve 30.5 g of dry main raw material 4 in 80 mL of EMC to prepare a first mixed solution for later use. In a 500 mL three-necked flask equipped with a thermometer, first add 60 mL of EMC, and then add 9.2 g of potassium hexafluorophosphate while shaking. After the addition is complete, a second mixed solution is obtained. The molar ratio of dry main raw material 4 to potassium hexafluorophosphate is 2:1;

[0272] (2) Under a nitrogen atmosphere, heat the second mixed solution to 50 °C, and dropwise add the first mixed solution to the second mixed solution. After the addition is complete, continue to stir and react at 50 °C until there is basically no gas generated in the tail gas absorption solution. Cool and filter the resulting turbid liquid after the reaction to obtain a small amount of insoluble matter. Remove the solvent from the filtrate under reduced pressure, add 25 mL of toluene, and stir at room temperature to precipitate a large amount of white solid. After filtration, washing, and drying, 19.6 g of white solid is obtained, which is fluorophosphorus compound No. 24.

[0273] The measured purity is 99.2%, the moisture content is 61 ppm, and the acid value is 60 ppm.

[0274] After elemental analysis:

[0275] Element C H O P F K Element content % 39.61 4.75 30.21 7.26 8.96 9.21

[0276] Prepare the fluorophosphorus compounds in Examples 1-24 into LiNiO·6COO·2MnO·2O2 / Li batteries or Na3V2(PO4)3 / Na batteries and conduct relevant tests as follows:

[0277] I. Preparation of LiNiO·6COO·2MnO·2O2 / Li button battery:

[0278] Prepare a positive electrode slurry by mixing LiCOO·6NiO·2MnO·2O2 powder (80 wt%), carbon black (10 wt%), polyvinylidene fluoride (PVDF 10 wt%), and N-methylpyrrolidone (NMP). Coat the mixed slurry on aluminum foil using an automatic coater, and place the coated electrode sheet in a vacuum oven at 90 °C for 12 h. The next day, roll and cut the large electrode sheet into small 16 mm round pieces at room temperature. Then place the cut small round pieces in a vacuum at 90 °C for 12 h. The dried electrode sheet is assembled into a 2025-type button battery with a separator, electrolyte, lithium sheet, and positive and negative electrode casings in a glove box filled with argon (moisture <1 ppm, oxygen content <1 ppm).

[0279] Among them, the electrolyte composition is as follows:

[0280] The concentration of lithium salt LiPF6 is 1.0 mol·L -1, the organic solvents EC:EMC:DMC = 1:1:1 (mass ratio), which is defined as baseA. Additionally, a fluorophosphorus compound accounting for 0.5 - 28% of the total mass of the electrolyte is added, and fluoroethylene carbonate (FEC) accounting for 1 - 8% of the total mass of the electrolyte is selectively added. The prepared electrolyte is added to the button cell.

[0281] II. Preparation of Na3V2(PO4)3 / Na button cell:

[0282] The positive electrode slurry is prepared by mixing Na3V2(PO4)3 powder (80 wt%), carbon black (10 wt%), polyvinylidene fluoride (PVDF 10 wt%) and N-methylpyrrolidone (NMP). The mixed slurry is coated on the aluminum foil with an automatic coater, and the coated electrode sheet is placed in a vacuum oven at 90 °C for 12 h of drying. The next day, the large electrode sheet is rolled and cut into small round pieces with a diameter of 16 mm at room temperature. Then the cut small round pieces are placed in a vacuum at 90 degrees for 12 h. The dried electrode sheet is assembled into a 2025-type button cell with a separator, electrolyte, sodium sheet, and positive and negative electrode casings in a glove box filled with argon (moisture < 1 ppm, oxygen content < 1 ppm).

[0283] Among them, the electrolyte composition is as follows:

[0284] The concentration of sodium salt NaPF6 is 1.0 mol·L -1 , the organic solvents EC:EMC:DMC = 1:1:1 (mass ratio), which is defined as baseB. Additionally, a fluorophosphorus compound accounting for 0.5 - 28% of the total mass of the electrolyte is added, and fluoroethylene carbonate (FEC) accounting for 1 - 8% of the total mass of the electrolyte is selectively added. The prepared electrolyte is added to the button cell.

[0285] Examples 25 - 56 and Comparative Examples 1 - 4

[0286] Example 25: The electrolyte composition of this example is baseA + 0.5% fluorophosphorus compound No. 1 + 6% FEC.

[0287] Example 26: The electrolyte composition of this example is baseA + 0.5% fluorophosphorus compound No. 1.

[0288] Example 27: The electrolyte composition of this example is baseB + 0.5% fluorophosphorus compound No. 2 + 6% FEC.

[0289] Example 28: The electrolyte composition of this example is baseB + 0.5% fluorophosphorus compound No. 2.

[0290] Example 29: The electrolyte composition of this example is baseA + 1% fluorophosphorus compound No. 4 + 3% FEC.

[0291] Example 30: The electrolyte composition of this example is baseA + 1% fluorophosphorus compound No. 4.

[0292] Example 31: The electrolyte composition of this example is baseB + 1% fluorophosphorus compound No. 5 + 3% FEC.

[0293] Example 32: The electrolyte composition of this example is baseB + 1% fluorophosphorus compound No. 5.

[0294] Example 33: The electrolyte composition of this example is baseA + 10% fluorophosphorus compound No. 7 + 5% FEC.

[0295] Example 34: The electrolyte composition of this example is baseA + 10% fluorophosphorus compound No. 7.

[0296] Example 35: The electrolyte composition of this example is baseB + 10% fluorophosphorus compound No. 8 + 5% FEC.

[0297] Example 36: The electrolyte composition of this example is baseB + 10% fluorophosphorus compound No. 8.

[0298] Example 37: The electrolyte composition of this example is baseA + 28% fluorophosphorus compound No. 10 + 1% FEC.

[0299] Example 38: The electrolyte composition of this example is baseA + 28% fluorophosphorus compound No. 10.

[0300] Example 39: The electrolyte composition of this example is baseB + 28% fluorophosphorus compound No. 11 + 1% FEC.

[0301] Example 40: The electrolyte composition of this example is baseB + 28% fluorophosphorus compound No. 11.

[0302] Example 41: The electrolyte composition of this example is baseA + 0.5% fluorophosphorus compound No. 13 + 8% FEC.

[0303] Example 42: The electrolyte composition of this example is baseA + 0.5% fluorophosphorus compound No. 13.

[0304] Example 43: The electrolyte composition of this example is baseB + 1% fluorophosphorus compound No. 14 + 3% FEC.

[0305] Example 44: The electrolyte composition of this example is baseB + 1% fluorophosphorus compound No. 14.

[0306] Example 45: The electrolyte composition of this example is baseA + 12% fluorophosphorus compound No. 16 + 3% FEC.

[0307] Example 46: The electrolyte composition of this example is baseA + 12% fluorophosphorus compound No. 16.

[0308] Example 47: The electrolyte composition of this example is baseB + 20% fluorophosphorus compound No. 17 + 1% FEC.

[0309] Example 48: The electrolyte composition of this example is baseB + 20% fluorophosphorus compound No. 17.

[0310] Example 49: The electrolyte composition of this example is baseA + 1% fluorophosphorus compound No. 19 + 6% FEC.

[0311] Example 50: The electrolyte composition of this example is baseA + 1% fluorophosphorus compound No. 19.

[0312] Example 51: The electrolyte composition of this example is baseB + 10% fluorophosphorus compound No. 20 + 4% FEC.

[0313] Example 52: The electrolyte composition of this example is baseB + 10% fluorophosphorus compound No. 20.

[0314] Example 53: The electrolyte composition of this example is baseA + 18% fluorophosphorus compound No. 22 + 7% FEC.

[0315] Example 54: The electrolyte composition of this example is baseA + 18% fluorophosphorus compound No. 22.

[0316] Example 55: The electrolyte composition of this example is baseB + 28% fluorophosphorus compound No. 23 + 7% FEC.

[0317] Example 56: The electrolyte composition of this example is baseB + 28% fluorophosphorus compound No. 23.

[0318] Comparative Example 1: The electrolyte composition is baseA + 5% FEC.

[0319] Comparative Example 2: The electrolyte composition is baseA.

[0320] Comparative Example 3: The electrolyte composition is baseB + 5% FEC.

[0321] Comparative Example 4: The electrolyte composition is baseB.

[0322] The electrolytes prepared in Examples 25 - 56 and Comparative Examples 1 - 4 were added to button cells, and the cycle performance of the prepared button cells was tested at room temperature. The test results of lithium-ion batteries are shown in Table 1, and the test results of sodium-ion batteries are shown in Table 2.

[0323] The test conditions are as follows: constant current charge at 0.1C to 4.5V, constant current discharge at 0.1C to 2.8V, cycle 3 weeks, constant current charge at 0.5C to 4.5V, constant current discharge at 0.5C to 2.8V, cycle 200 weeks.

[0324] Table 1 Test results of lithium-ion batteries

[0325]

[0326]

[0327] Table 2 Test results of sodium-ion batteries

[0328] Experiment number Initial Coulombic efficiency (%) Battery capacity retention rate after 200 cycles at 0.5C (%) Example 27 93.6 93.3 Example 28 87.1 93.1 Example 31 92.8 92.7 Example 32 86.2 91.1 Example 35 91.9 92.4 Example 36 86.7 92.1 Example 39 91.5 92.6 Example 40 86.8 92.5 Example 43 92.9 93.1 Example 44 87.1 92.7 Example 47 92.5 92.8 Example 48 86.7 91.2 Example 51 91.8 92.3 Example 52 86.5 91.9 Example 55 91.4 92.7 Example 56 87.1 92.6 Comparative example 3 88.1 83.7 Comparative example 4 83.2 81.5

[0329] From the results in Tables 1 - 2, by comparing Examples 25 - 56 with Comparative Examples 1 - 4, it can be seen that by adding the fluorophosphorus compound of the present invention, in the 0.5C cycle test of lithium batteries or sodium batteries, when the working voltage is 4.5V, both the initial Coulomb efficiency and the capacity retention rate are significantly improved. This is because the fluorophosphorus compound containing double bonds in the present invention will undergo a polymerization reaction, coat on the electrode, form a protective film on the electrode of the battery, and has a protective effect on the electrode of the battery, which has a positive effect on improving the high-temperature cycle performance and stability performance of lithium-ion batteries, thus being beneficial to extending the battery life and the safety of battery operation.

[0330] When the fluorophosphorus compound of the present invention and two types of additives of fluoroethylene carbonate are simultaneously added to lithium batteries or sodium batteries, compared with lithium batteries or sodium batteries only added with the fluorophosphorus compound of the present invention, the initial Coulomb efficiency of the battery is significantly improved, indicating that when the fluorophosphorus compound of the present invention is used in combination with fluoroethylene carbonate, it has an obvious advantage in improving the initial efficiency of lithium batteries or sodium batteries. This is because the fluorophosphorus compound of the present invention and fluoroethylene carbonate can undergo a polymerization reaction when added to the electrolyte to participate in the formation of the CEI (Chemical-Electrochemical Interface) film, reduce the irreversible capacity loss of lithium batteries or sodium batteries, improve the utilization rate of the positive electrode material, and this CEI film simultaneously inhibits the decomposition of the electrolyte and reduces the electrochemical impedance of the battery, thereby improving the cycle stability of lithium batteries or sodium batteries.

[0331] The above are only several preferred embodiments of the present application, and do not impose any form of limitation on the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the disclosed technical content above is equivalent to equivalent implementation cases and all belong to the scope of the technical solution.

Claims

1. A fluorophosphorus compound, characterized in that, It includes the following structural formulas Ⅰ and Ⅱ: Among them, R1, R2, R3, and R4 are independently selected from a hydrogen atom, a C 1-12 linear saturated hydrocarbon group, a C 1-12 linear unsaturated hydrocarbon group, an aromatic group, a C 1-12 silyl group, an allyloxy group, an allyloxyalkyl group, an acyloxy group containing a saturated hydrocarbon group, an acyloxyalkyl group containing a saturated hydrocarbon group, an acyloxy group containing an unsaturated hydrocarbon group, or an acyloxyalkyl group containing an unsaturated hydrocarbon group; Among them, C 1-12 linear saturated hydrocarbon group, C 1-12 linear unsaturated hydrocarbon group, aromatic group, C 1-12 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing saturated hydrocarbon group, acyloxyalkyl group containing saturated hydrocarbon group, acyloxy group containing unsaturated hydrocarbon group and acyloxyalkyl group containing unsaturated hydrocarbon group are each independently unsubstituted or substituted by a halogen element or a phenyl group; The M + is an alkali metal ion or a quaternary ammonium salt type cation.

2. The fluorophosphorus compound according to claim 1, wherein The R1, R2, R3, and R4 are independently selected from a hydrogen atom, C 1-6 linear saturated hydrocarbon group, C 1-6 linear unsaturated hydrocarbon group, aromatic group, C 1-6 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing a saturated hydrocarbon group, acyloxyalkyl group containing a saturated hydrocarbon group, acyloxy group containing an unsaturated hydrocarbon group, or acyloxyalkyl group containing an unsaturated hydrocarbon group; Among them, C 1-6 linear saturated hydrocarbon group, C 1-6 linear unsaturated hydrocarbon group, aromatic group, C 1-6 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing saturated hydrocarbon group, acyloxyalkyl group containing saturated hydrocarbon group, acyloxy group containing unsaturated hydrocarbon group and acyloxyalkyl group containing unsaturated hydrocarbon group are each independently unsubstituted or substituted by a halogen element or a phenyl group; The alkali metal ion is Li + , Na + or K + ; The quaternary ammonium salt type cation is a tetramethylammonium ion or a tetrabutylammonium ion.

3. The fluorophosphorus compound according to claim 2, wherein The R1, R2, R3, and R4 are independently selected from a hydrogen atom, C 1-4 linear alkyl group, C 1-4 linear alkenyl group, C 1-4 linear alkynyl group, aryl group, C 1-4 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing a saturated hydrocarbon group, acyloxyalkyl group containing a saturated hydrocarbon group, acyloxy group containing an unsaturated hydrocarbon group, or acyloxyalkyl group containing an unsaturated hydrocarbon group; Among them, C 1-4 linear alkyl group, C 1-4 linear alkenyl group, C 1-4 linear alkynyl group, aryl group, C 1-4 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing a saturated hydrocarbon group, acyloxyalkyl group containing a saturated hydrocarbon group, acyloxy group containing an unsaturated hydrocarbon group, and acyloxyalkyl group containing an unsaturated hydrocarbon group are each independently unsubstituted or substituted with a halogen element or a phenyl group.

4. The fluorophosphorus compound according to claim 3, wherein The R1, R2, R3, and R4 are independently selected from one of a hydrogen atom, a methyl group, an ethyl group, a propyl group, an allyloxy group, an allyloxymethyl group, an acryloyloxy group, an acryloyloxymethyl group, a methacryloyloxy group, a methacryloyloxymethyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, a vinyl group, an allyl group, an isopropyl group, an allyl group, an isobutenyl group, a cyclopentadienyl group, a pentadienyl group, an ethynyl group, a pentynyl group, a phenyl group, a benzyl group, a phenethyl group, a trimethylsilyl group, a triethylsilyl group, a tert-butyldimethylsilyl group, a tert-butyldiphenylsilyl group, a diisopropylsilyl group, a diphenylsilyl group, or a diisopropylphenethylsilyl group.

5. The fluorophosphorus compound according to any one of claims 1-4, characterized in that, The structure is as follows:

6. The fluorophosphorus compound according to any one of claims 1-5, characterized in that, It is obtained by reacting a main raw material with hexafluorophosphate; the structural formula of the main raw material is Among them, the R1 and R2 are independently selected from a hydrogen atom, C 1-12 linear saturated hydrocarbon group, C 1-12 linear unsaturated hydrocarbon group, aromatic group, C 1-12 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing a saturated hydrocarbon group, acyloxyalkyl group containing a saturated hydrocarbon group, acyloxy group containing an unsaturated hydrocarbon group, or acyloxyalkyl group containing an unsaturated hydrocarbon group; Among them, C 1-12 linear saturated hydrocarbon group, C 1-12 linear unsaturated hydrocarbon group, aromatic group, C 1-12 silyl group, allyloxy group, allyloxyalkyl group, acyloxy group containing saturated hydrocarbon group, acyloxyalkyl group containing saturated hydrocarbon group, acyloxy group containing unsaturated hydrocarbon group, and acyloxyalkyl group containing unsaturated hydrocarbon group are each independently unsubstituted or substituted by a halogen element or a phenyl group.

7. An electrolyte, characterized in that, It contains the fluorophosphorus compound described in any one of claims 1-5.

8. The electrolyte according to claim 7, wherein It further includes an alkali metal salt and an aprotic solvent; Preferably, the alkali metal salt includes a lithium salt and / or a sodium salt; Preferably, the lithium salt is at least one of lithium hexafluorophosphate, lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium difluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, or lithium bis(fluorosulfonyl)imide; Preferably, the sodium salt is at least one of sodium hexafluorophosphate, sodium bis(oxalato)borate, sodium difluoro(oxalato)borate, sodium difluorophosphate, sodium bis(trifluoromethanesulfonyl)imide, or sodium bis(fluorosulfonyl)imide; Preferably, the aprotic solvent is at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl acetate, methyl propionate, ethyl propionate, or propyl propionate; Preferably, the mass concentration of the fluorophosphorus compound in the electrolyte is 0.5-28%; the molar concentration of the alkali metal salt in the electrolyte is 0.5-3 mol / L.

9. The electrolyte according to claim 7 or 8, characterized in that, It further includes fluorinated ethylene carbonate; Preferably, the mass concentration of the fluorinated ethylene carbonate in the electrolyte is 1-8%.

10. A secondary battery, characterized in that, It contains the fluorophosphorus compound described in any one of claims 1-5; and / or contains the electrolyte described in any one of claims 7-9.

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