Phosphorus-containing compound as well as preparation method and application thereof

Abstract

The invention discloses a phosphorus-containing compound and a preparation method and application thereof, the structural general formula is as follows: # imgabs0 #, the compound can increase the concentration of ions in an electrolyte, lithium ions, sodium ions, potassium ions and the like in the electrolyte can enhance the conductivity of the electrolyte, and after the additive is added, the conductivity of the electrolyte can be improved. According to the present invention, the large internal resistance of the battery during the high-voltage charge-discharge process can be inhibited, and the stability of the electrode material can be improved, such that the high initial coulombic efficiency and the good cycle performance of the secondary battery under the high voltage can be achieved. The electrolyte additive provided by the invention has a remarkable improvement effect on the first coulombic efficiency and cycle performance of various secondary battery systems under high voltage.

Description

Technical Field

[0001] The invention belongs to the technical field of secondary battery electrolytes, and in particular relates to phosphorus-containing compounds and preparation methods and applications thereof. Background Art

[0002] In recent years, secondary batteries have been widely used in 3C digital products, new energy electric vehicles, energy storage power stations, etc. Energy density, service life, safety and high current charging and discharging capacity are the core parameters for evaluating battery performance. At the same time, considering the regional environmental differences, high and low temperature performance is also a technical problem that needs to be overcome.

[0003] Improving the energy density of secondary batteries is one of the important development directions. Whether it is for small energy storage devices or electric vehicles, smaller and lighter batteries are the hot spots pursued by the secondary battery market. The energy density of secondary batteries can be improved by increasing the charging voltage of the positive electrode material of the battery. However, while increasing the voltage of the positive electrode material, the battery performance such as the charge and discharge cycle of the battery is declining, among which high-voltage electrolyte becomes one of the key restrictive factors. Under high voltage (≥4.35V vsLi / Li), the oxidation activity of the positive electrode material increases, causing the electrolyte to undergo oxidation reaction on the electrode surface, resulting in an increase in the irreversible capacity of the secondary battery, while causing the first coulomb efficiency of the battery to decrease, the utilization rate of the positive electrode material to decrease, and the battery capacity to decrease. Therefore, it is necessary to develop an electrolyte that can withstand high voltage so that the secondary battery can achieve high first coulomb efficiency and good cycle performance under high voltage. Summary of the invention

[0004] Technical problem to be solved: In response to the above technical problem, the present invention provides a phosphorus-containing compound and a preparation method and application thereof, which are suitable for improving the first coulombic efficiency and cycle performance of secondary batteries under high voltage.

[0005] Technical solution: Phosphorus-containing compound, the general structural formula is as follows:

[0006]

[0007] Wherein, R1, R2, R3, R4, R5, and R6 are independently selected from hydrogen atoms, C 1-12 Linear saturated hydrocarbon, C 1-12 Linear unsaturated hydrocarbon, aromatic, C 1-12 One of a silane 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;

[0008] Among them, C 1-12 Linear saturated hydrocarbon, C 1-12 Linear unsaturated hydrocarbon, aromatic, C 1-12The 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;

[0009] The M + It is an alkali metal ion or a quaternary ammonium salt type cation.

[0010] In one preferred embodiment, R1, R2, R3, R4, R5, and R6 are independently selected from hydrogen atoms, C 1-6 Linear saturated hydrocarbon, C 1-6 Linear unsaturated hydrocarbon, aromatic, C 1-6 One of silane, allyloxy, allyloxyalkyl, acyloxy containing saturated hydrocarbon group, acyloxyalkyl containing saturated hydrocarbon group, acyloxy containing unsaturated hydrocarbon group, or acyloxyalkyl containing unsaturated hydrocarbon group; wherein C 1-6 Linear saturated hydrocarbon, C 1-6 Linear unsaturated hydrocarbon, aromatic, C 1-6 The 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 halogen element or phenyl group; the alkali metal ion is Li + 、Na + or K + The quaternary ammonium salt cation is a tetramethylammonium ion (C4H 12 N + ), tetrabutylammonium ion (C 16 H 36 N + ).

[0011] In the second preferred embodiment, R1, R2, R3, R4, R5 and R6 are independently selected from hydrogen atoms, C 1-4 Linear alkyl, C 1-4 Linear olefinic group, C 1-4 Linear alkynyl, aromatic, C 1-4 One of silane, allyloxy, allyloxyalkyl, acyloxy containing saturated hydrocarbon group, acyloxyalkyl containing saturated hydrocarbon group, acyloxy containing unsaturated hydrocarbon group, or acyloxyalkyl containing unsaturated hydrocarbon group; wherein C 1-4 Linear alkyl, C 1-4 Linear olefinic group, C 1-4 Linear alkynyl, aromatic, C 1-4 The silyl group, allyloxy group, allyloxyalkyl group, saturated hydrocarbon group-containing acyloxy group, saturated hydrocarbon group-containing acyloxyalkyl group, unsaturated hydrocarbon group-containing acyloxy group and unsaturated hydrocarbon group-containing acyloxyalkyl group are each independently unsubstituted or substituted with a halogen element or a phenyl group.

[0012] In a third preferred embodiment, R1, R2, R3, R4, R5 and R6 are independently selected from a hydrogen atom, a methyl group, an ethyl group, a propyl group, an allyloxy group, an allyloxymethyl group, an acryloyloxy group, an acryloyloxymethyl group, an isoacryloyloxy group, an isoacryloyloxymethyl 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 isoallyl group, an allylic group, an isoallylic 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.

[0013] The above phosphorus-containing compound has the following specific structure:

[0014]

[0015]

[0016] The preparation method of the above phosphorus-containing compound is obtained by reacting a main raw material with hexafluorophosphate; the main raw material has the structural formula

[0017]

[0018] Wherein, R1 and R2 are independently selected from hydrogen atoms, C 1-12 Linear saturated hydrocarbon, C 1-12 Linear unsaturated hydrocarbon, aromatic, C 1-12 One of a silane 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;

[0019] Among them, C 1-12 Linear saturated hydrocarbon, C 1-12 Linear unsaturated hydrocarbon, aromatic, C 1-12 The silyl group, allyloxy group, allyloxyalkyl group, saturated hydrocarbon group-containing acyloxy group, saturated hydrocarbon group-containing acyloxyalkyl group, unsaturated hydrocarbon group-containing acyloxy group and unsaturated hydrocarbon group-containing acyloxyalkyl group are each independently unsubstituted or substituted with a halogen element or a phenyl group.

[0020] The hexafluorophosphate is selected from lithium hexafluorophosphate, sodium hexafluorophosphate, potassium hexafluorophosphate, tetramethylammonium hexafluorophosphate, and tetrabutylammonium hexafluorophosphate.

[0021] An electrolyte contains the above-mentioned phosphorus-containing compound.

[0022] Furthermore, the electrolyte further comprises a lithium salt and an aprotic solvent, or further comprises a sodium salt and an aprotic solvent.

[0023] The lithium salt is at least one of lithium hexafluorophosphate, lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium difluorophosphate, lithium bis(trifluoromethanesulfonylimide) and lithium bis(fluorosulfonylimide).

[0024] The sodium salt is at least one of sodium hexafluorophosphate, sodium bis(oxalatoborate), sodium difluorooxalatoborate, sodium difluorophosphate, sodium bis(trifluoromethanesulfonyl imide) and sodium bis(fluorosulfonyl imide).

[0025] 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 and propyl propionate.

[0026] The mass concentration of the phosphorus-containing compound in the above electrolyte is 0.5-20%; the molar concentration of the lithium salt in the electrolyte is 1-2 mol / L.

[0027] Preferably, the electrolyte further comprises fluoroethylene carbonate; the mass concentration of fluoroethylene carbonate in the electrolyte is 1-8%.

[0028] A secondary battery, which is a lithium ion battery or a sodium ion battery, contains the phosphorus-containing compound mentioned above; and / or contains the electrolyte mentioned above.

[0029] Beneficial effects: The present invention provides a phosphorus-containing compound, which is applied to electrolyte additives of secondary batteries, and increases the concentration of ions in the electrolyte. The lithium ions, sodium ions, potassium ions, etc. in the electrolyte can enhance the conductivity of the electrolyte of the secondary battery. After the addition of such additives, it can suppress the occurrence of large internal resistance of the battery during high-voltage charging and discharging and improve the stability of the electrode material, thereby achieving high first coulomb efficiency and good cycle performance of the secondary battery at high voltage. The electrolyte additive provided by the present invention has a significant effect on improving the first coulomb efficiency and cycle performance of various secondary battery systems (such as lithium ion batteries and sodium batteries containing ternary high nickel / medium nickel or lithium iron phosphate positive electrodes) at high voltage. DETAILED DESCRIPTION

[0030] The present invention is described in detail below by way of examples. The examples provide detailed implementation methods and specific operating steps, which are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention.

[0031] If M + For lithium ions, the preferred structure is:

[0032]

[0033]

[0034] If M +is a sodium ion, the preferred structure is:

[0035]

[0036] If M + is a potassium ion, the preferred structure is:

[0037]

[0038] Main raw material preparation example 1

[0039] Main raw material 1 is used as the main raw material of Examples 1-3. The preparation method of main raw material 1 is as follows:

[0040]

[0041] (1) 13.3 g (151.0 mmol) of dried butenediol, 35.6 g (351.8 mmol) of triethylamine and 150 mL of n-hexane were added to a 250 mL three-necked reaction flask, and the gas was replaced with nitrogen three times to ensure that there was no air in the reaction flask. The mixture was stirred and cooled in an ice-water bath. 32.8 g (302.0 mmol) of trimethylsilyl chloride was slowly added dropwise in an ice-water bath. After the addition was completed, the mixture was stirred and reacted at room temperature for 1 hour, and then heated to 60° C. and reacted for 24 hours.

[0042] (2) On the next day, a large amount of white solid was produced in the reaction flask. The temperature was cooled to about 0°C in an ice-water bath, filtered, and the filter cake was washed with 50 mL of n-hexane. The filtrates were combined and concentrated using a rotary evaporator to remove the solvent. The mixture was then vacuum distilled using an oil pump to collect the main fraction to obtain the main raw material 1.

[0043] Main raw material preparation example 2

[0044] Main raw material 2 is used as the main raw material of Examples 4-6. The preparation method of main raw material 2 is as follows:

[0045]

[0046] (1) Add 100 g (1.08 mol) of propylene glycol and 100 mL of ethyl acetate to a 500 mL three-necked flask, stir evenly, add 3-5 drops of concentrated sulfuric acid, slowly raise the temperature to 60°C, control the temperature at 60-70°C, add 58 g (1 mol) of allyl alcohol, keep the temperature at 60-70°C for 3 h after the addition is complete, stop the reaction, and concentrate the reaction solution to obtain about 140 g of S1.

[0047]

[0048] (2) Add 140 g (1 mol) of S1 obtained by concentration to 300 mL of tetrahydrofuran, stir and mix evenly, then concentrate 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 to obtain dried S1, then add the dried S1, 252 g (2.5 mol) of triethylamine and 600 mL of n-hexane to a 2000 mL three-necked reaction flask, replace the gas with nitrogen three times to ensure that there is no air in the reaction flask, keep stirring, cool it with an ice-water bath, and slowly drop 216 g (2 mol) of trimethylsilyl chloride in an ice-water bath. After dropping, stir and react at room temperature (this reaction is an exothermic reaction, so the temperature of the reaction solution will rise during the reaction) for 1 hour, then heat to 60°C and react for 24 hours.

[0049] (3) On the second day, a large amount of white solid was generated in the reaction flask. The reaction flask was cooled to about 0°C in an ice-water bath, filtered, and the filter cake was washed with 300 mL of n-hexane. The filtrates were combined and concentrated using a rotary evaporator to remove the solvent. The mixture was then vacuum distilled using an oil pump to collect the main fraction and obtain the main raw material 2.

[0050] Main raw material preparation example 3

[0051] Main raw material 3 is used as the main raw material of Examples 7-9. The preparation method of main raw material 3 is as follows:

[0052]

[0053] (1) Add 50 g (0.54 mol) of propylene glycol to a 500 mL three-necked flask, add 100 mL of ethyl acetate, stir evenly, add 3-5 drops of concentrated sulfuric acid, slowly raise the temperature to 60°C, control the temperature at 60-70°C, add 36 g (0.5 mol) of acrylic acid, keep the temperature at 60-70°C for 3 h after the addition is complete, stop the reaction, and concentrate the reaction solution to obtain about 76 g of S2.

[0054]

[0055] (2) Add 76 g (0.5 mol) of S2 obtained by concentration to 150 mL of tetrahydrofuran, stir and mix evenly, then concentrate on 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 S2, then add the dried S2, 126 g (1.25 mol) of triethylamine and 300 mL of n-hexane to a 1000 mL three-necked reaction flask, replace the gas with nitrogen three times to ensure that there is no air in the reaction flask, keep stirring, cool it with an ice-water bath, and slowly drip 108 g (1 mol) of trimethylsilyl chloride under ice-water bath conditions. After dripping, stir and react at room temperature (this reaction is an exothermic reaction, so the temperature of the reaction solution will rise during the reaction) for 1 hour, then heat to 60°C and react for 24 hours.

[0056] (3) On the next day, a large amount of white solid was produced in the reaction flask. The temperature was cooled to about 0°C in an ice-water bath, filtered, and the filter cake was washed with 300 mL of n-hexane. The filtrate was combined and concentrated using a rotary evaporator to remove the solvent. The mixture was then vacuum distilled using an oil pump to collect the main fraction to obtain the main raw material 3.

[0057] Main raw material preparation example 4

[0058] Main raw material 4 is used as the main raw material of Examples 10-12. The preparation method of main raw material 4 is as follows:

[0059]

[0060] (1) Add 50 g (0.54 mol) of propylene glycol to a 500 mL three-necked flask, add 100 mL of ethyl acetate, stir evenly, add 3-5 drops of concentrated sulfuric acid, slowly raise the temperature to 60°C, control the temperature at 60-70°C, add 43 g (0.5 mol) of 2-methylacrylic acid, keep the temperature at 60-70°C for 3 h after the addition is complete, stop the reaction, and concentrate the reaction solution to obtain about 82 g of S3.

[0061]

[0062] (2) Add 82 g (0.5 mol) of S3 obtained by concentration to 150 mL of tetrahydrofuran, stir and mix evenly, then concentrate on 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 S3, then add the dried S3, 126 g (1.25 mol) of triethylamine and 300 mL of n-hexane to a 1000 mL three-necked reaction flask, replace the gas with nitrogen three times to ensure that there is no air in the reaction flask, keep stirring, cool it with an ice-water bath, and slowly drip 108 g (1 mol) of trimethylsilyl chloride under ice-water bath conditions. After dripping, stir and react at room temperature (this reaction is an exothermic reaction, so the temperature of the reaction solution will rise during the reaction) for 1 hour, then heat to 60°C and react for 24 hours.

[0063] (3) On the second day, a large amount of white solid was generated in the reaction flask. The reaction flask was cooled to about 0°C in an ice-water bath and filtered. The filter cake was washed with 300 mL of n-hexane. The filtrates were combined and concentrated using a rotary evaporator to remove the solvent. The mixture was then vacuum distilled using an oil pump to collect the main fraction and obtain the main raw material 4.

[0064] Example 1

[0065] The structural formula of phosphorus-containing compound No. 1 is:

[0066]

[0067] The preparation of phosphorus-containing compound No. 1, the synthetic route is as follows:

[0068]

[0069] (1) Add the main raw material 1 to 200 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the EMC solvent and water in the main raw material 1 to obtain a dry main raw material 1;

[0070] (2) Dissolve 70 g of the dried main raw material 1 in 200 mL of EMC to prepare a first mixed solution for standby use. In a 1 L three-necked flask with a thermometer, add 65 mL of EMC and then add 15.2 g of lithium hexafluorophosphate, while shaking. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 1 to the lithium hexafluorophosphate is 3:1;

[0071] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 52 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. After filtering, washing, and drying, 26.3 g of white solid was obtained, which was phosphorus-containing compound No. 1.

[0072] The purity was determined by using a Thermo Fisher ion chromatograph (model ICS-600) to be 99.8%, with a moisture content of 56 ppm and an acid value of 75 ppm.

[0073] The nuclear magnetic resonance spectrometer (model: picoSpin 45) was used to measure the H NMR spectrum data of compound 1:

[0074] 1H-NMR (400MHz, CDCl3)3.49-3.52(d,2H),4.17-4.20(m,1H),5.11-5.14(d,1H),5.23-5.29(d,1H),5.85-5.89(m,1H).

[0075] The elemental analysis was performed using a Thermo Fisher organic element analyzer (model: FlashSmart), and the following results were obtained:

[0076] element C H O P Li Element content% 48.67 5.96 32.55 10.39 2.43

[0077] Note: Examples 1-12 in this application all use Thermo Fisher ion chromatograph (model ICS-600) to measure purity, moisture and acid value. Examples 1-12 in this application all use Thermo Fisher organic element analyzer (model FlashSmart) for element analysis.

[0078] Example 2

[0079] The structural formula of phosphorus-containing compound No. 2 is:

[0080]

[0081] The preparation of phosphorus-containing compound No. 2, the synthetic route is as follows:

[0082]

[0083] (1) Add the main raw material 1 to 240 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the EMC solvent and water in the main raw material 1 to obtain a dry main raw material 1;

[0084] (2) Dissolve 34.8 g of the dried main raw material 1 in 200 mL of EMC to prepare a first mixed solution for standby use. In a 1 L three-necked flask with a thermometer, first add 60 mL of EMC and then add 8.4 g of sodium hexafluorophosphate, while shaking. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 1 to the sodium hexafluorophosphate is 3:1;

[0085] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 30 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. The white solid was filtered, washed, and dried to obtain 13.4 g of a white solid, which was phosphorus-containing compound No. 2.

[0086] The purity was 99.3% as determined by ion chromatography, the water content was 48 ppm, and the acid value was 58 ppm.

[0087] After elemental analysis:

[0088] element C H O P Na Element content% 46.17 5.72 30.78 9.89 7.44

[0089] Example 3

[0090] The structural formula of phosphorus-containing compound No. 3 is:

[0091]

[0092] The preparation of phosphorus-containing compound No. 3, the synthetic route is as follows:

[0093]

[0094] (1) Add the main raw material 1 to 80 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the EMC solvent and water in the main raw material 1 to obtain a dry main raw material 1;

[0095] (2) Dissolve 23.2 g of the dried main raw material 1 in 60 mL of EMC to prepare a first mixed solution for standby use. In a 500 mL three-necked flask with a thermometer, first add 40 mL of EMC and then add 6.1 g of potassium hexafluorophosphate, while shaking. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 1 to potassium hexafluorophosphate is 3:1;

[0096] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 20 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. After filtering, washing, and drying, 8.3 g of white solid was obtained, which was phosphorus-containing compound No. 3.

[0097] The purity was 99.6% as determined by ion chromatography, the water content was 58 ppm, and the acid value was 73 ppm.

[0098] After elemental analysis:

[0099] element C H O P K Element content% 43.92 5.42 29.32 9.44 11.9

[0100] Example 4

[0101] The structural formula of phosphorus-containing compound No. 4 is:

[0102]

[0103] The preparation of phosphorus-containing compound No. 4, the synthetic route is as follows:

[0104]

[0105] (1) Add the main raw material 2 to 150 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the EMC solvent and water in the main raw material 2 to obtain a dry main raw material 2;

[0106] (2) Dissolve 27.6 g of dried main raw material 2 in 100 mL of EMC to prepare a first mixed solution for standby use. Add 50 mL of EMC and then 5 g of lithium hexafluorophosphate to a 500 mL three-necked flask with a thermometer, while shaking. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 2 to the lithium hexafluorophosphate is 3:1;

[0107] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 20 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. The solid was filtered, washed, and dried to obtain 9.5 g of a white solid, which was phosphorus-containing compound No. 4.

[0108] The purity was 99.2% as determined by ion chromatography, the water content was 65ppm, and the acid value was 71ppm.

[0109] After elemental analysis:

[0110] element C H O P Li Element content% 50.38 6.99 33.68 7.30 1.65

[0111] Example 5

[0112] The structural formula of phosphorus-containing compound No. 5 is

[0113]

[0114] The preparation of phosphorus-containing compound No. 5, the synthetic route is as follows:

[0115]

[0116] (1) Add the main raw material 2 to 150 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the EMC solvent and water in the main raw material 2 to obtain a dry main raw material 2;

[0117] (2) Dissolve 27.6 g of dried main raw material 2 in 100 mL of EMC to prepare a first mixed solution for standby use. Add 50 mL of EMC to a 500 mL three-necked flask with a thermometer, then add 5.6 g of sodium hexafluorophosphate, and shake while adding. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 2 to the sodium hexafluorophosphate is 3:1;

[0118] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 20 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. The white solid was filtered, washed, and dried to obtain 10.7 g of a white solid, which was phosphorus-containing compound No. 5.

[0119] The purity was 99.3% as determined by ion chromatography, the water content was 57 ppm, and the acid value was 73 ppm.

[0120] After elemental analysis:

[0121] element C H O P Na Element content% 48.62 6.78 32.38 6.98 5.24

[0122] Example 6

[0123] The structural formula of phosphorus-containing compound No. 6 is

[0124]

[0125] The preparation of phosphorus-containing compound No. 6, the synthetic route is as follows:

[0126]

[0127] (1) Add the main raw material 2 to 150 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the solvent and water in the main raw material 2 to obtain a dry main raw material 2;

[0128] (2) Dissolve 27.6 g of dried main raw material 2 in 100 mL of EMC to prepare a first mixed solution for standby use. Add 50 mL of EMC to a 500 mL three-necked flask with a thermometer, then add 6.13 g of potassium hexafluorophosphate, and shake while adding. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 2 to potassium hexafluorophosphate is 3:1;

[0129] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 20 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. The white solid was filtered, washed, and dried to obtain 11.2 g of a white solid, which was phosphorus-containing compound No. 6.

[0130] The purity was 99.1%, the water content was 51ppm, and the acid value was 74ppm as determined by ion chromatography.

[0131] After elemental analysis:

[0132] element C H O P K Element content% 46.92 6.52 31.25 6.68 8.63

[0133] Example 7

[0134] The structural formula of phosphorus-containing compound No. 7 is:

[0135]

[0136] The preparation of phosphorus-containing compound No. 7, the synthetic route is as follows:

[0137]

[0138] (1) Add the main raw material 3 to 150 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the solvent and water in the main raw material 3 to obtain a dry main raw material 3;

[0139] (2) Dissolve 29.5 g of the dried main raw material 3 in 100 mL of EMC to prepare a first mixed solution for standby use. Add 50 mL of EMC to a 500 mL three-necked flask with a thermometer, then add 5.06 g of lithium hexafluorophosphate, and shake while adding. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 3 to the lithium hexafluorophosphate is 3:1;

[0140] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 20 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. The white solid was filtered, washed, and dried to obtain 12.9 g of white solid, which was phosphorus-containing compound No. 7.

[0141] The purity was 99.5%, the water content was 62ppm, and the acid value was 75ppm as determined by ion chromatography.

[0142] After elemental analysis:

[0143] element C H O P Li Element content% 45.98 5.12 40.83 6.61 1.46

[0144] Example 8

[0145] The structural formula of phosphorus-containing compound No. 8 is:

[0146]

[0147] The preparation of phosphorus-containing compound No. 8, the synthetic route is as follows:

[0148]

[0149] (1) Add the main raw material 3 to 150 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the solvent and water in the main raw material 3 to obtain a dry main raw material 3;

[0150] (2) Dissolve 29.5 g of the dried main raw material 3 in 100 mL of EMC to prepare a first mixed solution for standby use. In a 500 mL three-necked flask with a thermometer, first add 50 mL of EMC and then add 5.6 g of sodium hexafluorophosphate, while shaking. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 3 to the sodium hexafluorophosphate is 3:1;

[0151] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 25 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. The white solid of 12.2 g was obtained by filtering, washing, and drying, which was phosphorus-containing compound No. 8.

[0152] The purity was 98.8%, the water content was 58ppm, and the acid value was 66ppm as determined by ion chromatography.

[0153] After elemental analysis:

[0154] element C H O P Na Element content% 44.43 4.94 39.44 6.34 4.85

[0155] Example 9

[0156] The structural formula of phosphorus-containing compound No. 9 is:

[0157]

[0158] The preparation of phosphorus-containing compound No. 9, the synthetic route is as follows:

[0159]

[0160] (1) Add the main raw material 3 to 150 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the solvent and water in the main raw material 3 to obtain a dry main raw material 3;

[0161] (2) Dissolve 29.5 g of the dried main raw material 3 in 100 mL of EMC to prepare a first mixed solution for standby use. In a 500 mL three-necked flask with a thermometer, first add 50 mL of EMC and then add 6.13 g of potassium hexafluorophosphate, while shaking. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 3 to potassium hexafluorophosphate is 3:1;

[0162] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 28 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. The white solid was filtered, washed, and dried to obtain 13.4 g of a white solid, which was phosphorus-containing compound No. 9.

[0163] The purity was 98.8%, the water content was 66ppm, and the acid value was 67ppm as determined by ion chromatography.

[0164] After elemental analysis:-

[0165] element C H O P K Element content% 43.02 4.75 38.18 6.19 7.86

[0166] Example 10

[0167] The structural formula of phosphorus-containing compound No. 10 is:

[0168]

[0169] The preparation of phosphorus-containing compound No. 10, the synthetic route is as follows:

[0170]

[0171] (1) Add the main raw material 4 to 150 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the solvent and water in the main raw material 4 to obtain a dry main raw material 4;

[0172] (2) Dissolve 30.5 g of dried main raw material 4 in 100 mL of EMC to prepare a first mixed solution for standby use. Add 50 mL of EMC to a 500 mL three-necked flask with a thermometer, then add 5 g of lithium hexafluorophosphate, and shake while adding. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 4 to the lithium hexafluorophosphate is 3:1;

[0173] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 20 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. The solid was filtered, washed, and dried to obtain 13.1 g of a white solid, which was phosphorus-containing compound No. 10.

[0174] The purity was 99.6% as determined by ion chromatography, the water content was 51 ppm, and the acid value was 64 ppm.

[0175] After elemental analysis:

[0176] element C H O P Li Element content% 49.22 5.83 37.44 6.09 1.42

[0177] Embodiment 11

[0178] The structural formula of phosphorus-containing compound No. 11 is:

[0179]

[0180] The preparation of phosphorus-containing compound No. 11, the synthetic route is as follows:

[0181]

[0182] (1) Add the main raw material 4 to 150 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the solvent and water in the main raw material 4 to obtain a dry main raw material 4;

[0183] (2) Dissolve 30.5 g of the dried main raw material 4 in 100 mL of EMC to prepare a first mixed solution for standby use. Add 50 mL of EMC to a 500 mL three-necked flask with a thermometer, then add 5.6 g of sodium hexafluorophosphate, and shake while adding. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 4 to the sodium hexafluorophosphate is 3:1;

[0184] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 22 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. The solid was filtered, washed, and dried to obtain 13.3 g of a white solid, which was phosphorus-containing compound No. 11.

[0185] The purity was 99.3% as determined by ion chromatography, the water content was 54 ppm, and the acid value was 75 ppm.

[0186] After elemental analysis:

[0187] element C H O P Na Element content% 47.66 5.69 36.31 5.87 4.47

[0188] Example 12

[0189] The structural formula of phosphorus-containing compound No. 12 is:

[0190]

[0191] The preparation of phosphorus-containing compound No. 12, the synthetic route is as follows:

[0192]

[0193] (1) Add the main raw material 4 to 150 mL of EMC solvent, stir and mix evenly, and then vacuum concentrate to remove the solvent and water in the main raw material 4 to obtain a dry main raw material 4;

[0194] (2) Dissolve 30.5 g of the dried main raw material 4 in 100 mL of EMC to prepare a first mixed solution for standby use. Add 50 mL of EMC to a 500 mL three-necked flask with a thermometer, then add 6.13 g of potassium hexafluorophosphate, and shake while adding. After the addition is completed, a second mixed solution is obtained; wherein the molar ratio of the dried main raw material 4 to potassium hexafluorophosphate is 3:1;

[0195] (3) The second mixed liquid was heated to 50° C. under a nitrogen atmosphere, and the first mixed liquid was added dropwise to the second mixed liquid. After the addition was completed, the reaction was continued at 50° C. with stirring until substantially no gas was generated in the tail gas absorption liquid. The turbid liquid obtained after the reaction was cooled and filtered to obtain a small amount of insoluble matter. The filtrate was decompressed to remove the solvent, and 22 ml of toluene was added and stirred at room temperature to precipitate a large amount of white solid. The white solid was filtered, washed, and dried to obtain 13.5 g of a white solid, which was phosphorus-containing compound No. 12.

[0196] The purity was 99.1%, the water content was 52ppm, and the acid value was 71ppm as determined by ion chromatography.

[0197] After elemental analysis:

[0198] element C H O P K Element content% 46.25 5.53 35.27 5.66 7.29

[0199] The phosphorus-containing compounds in Examples 1-12 were prepared into LiNiO·6COO·2MnO·2O2 / Li batteries or Na3V2(PO4)3 / Na batteries, and relevant tests were performed as follows:

[0200] 1. Preparation of LiNiO·6COO·2MnO·2O2 / Li button cell:

[0201] The positive electrode slurry was prepared by mixing LiCOO·6NiO·2MnO·2O2 powder (80 wt%), carbon black (10 wt%), polyvinylidene fluoride (PVDF 10 wt%) and N-methylpyrrolidone (NMP). The mixed slurry was coated on aluminum foil with an automatic coating machine, and the coated electrode was placed in a 90°C vacuum oven for drying for 12 hours. The next day, the large electrode was rolled and cut into 16 mm small discs at room temperature. The cut small discs were then placed in a 90-degree vacuum for 12 hours. The dried electrode was assembled into a 2025 button battery in a glove box filled with argon (water <1ppm, oxygen <1ppm) with a diaphragm, electrolyte, lithium sheet, and positive and negative electrode shells.

[0202] Among them, the lithium battery electrolyte composition is as follows:

[0203] Lithium salt LiPF6 concentration 1.0 mol·L -1 , organic solvent EC:EMC:DMC=1:1:1 (mass ratio), which is defined as baseA; in the present invention, the phosphorus-containing compound as an electrolyte additive accounts for 0.5-20% of the total mass of the electrolyte, and the additive fluoroethylene carbonate (FEC) accounts for 1-8% of the total mass of the electrolyte, and the electrolyte prepared above is added to a button battery.

[0204] 2. Preparation of Na3V2(PO4)3 / Na button battery:

[0205] The positive electrode slurry was prepared by mixing Na3V2(PO4)3 powder, carbon black (10 wt%), polyvinylidene fluoride (PVDF 10 wt%) and N-methylpyrrolidone (NMP). The mixed slurry was coated on aluminum foil with an automatic coating machine, and the coated electrode was placed in a 90°C vacuum oven for drying for 12 hours. The next day, the large electrode was rolled and cut into 16 mm small discs at room temperature. The cut small discs were then placed in a 90-degree vacuum for 12 hours. The dried electrode was assembled into a 2025 button battery with a diaphragm, electrolyte, sodium sheet, and positive and negative electrode shells in an argon-filled glove box (moisture <1ppm, oxygen <1ppm).

[0206] Among them, the sodium battery electrolyte composition is as follows:

[0207] Sodium salt NaPF6 concentration 1.0 mol·L -1 , organic solvent EC:EMC:DMC=1:1:1 (mass ratio), which is defined as base B; in the present invention, the phosphorus-containing compound as an electrolyte additive accounts for 0.5-20% of the total mass of the electrolyte, and the additive fluoroethylene carbonate (FEC) accounts for 1-8% of the total mass of the electrolyte, and the electrolyte prepared above is added to a button battery.

[0208] Examples 13-28

[0209] Example 13: The electrolyte composition of this example is baseA+0.5% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 1+3% FEC. The electrolyte prepared above is added into a button cell.

[0210] Example 14: The electrolyte composition of this example is baseA + 0.5% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 1. The electrolyte prepared above is added into a button cell.

[0211] Example 15: The electrolyte composition of this example is base B + 1% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 2 + 3% FEC. The electrolyte prepared above is added into a button cell.

[0212] Example 16: The electrolyte composition of this example is base B + 1% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 2. The electrolyte prepared above is added into a button cell.

[0213] Example 17: The electrolyte composition of this example is baseA+1% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 4+3% FEC. The electrolyte prepared above is added into a button cell.

[0214] Example 18: The electrolyte composition of this example is baseA + 1% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 4. The electrolyte prepared above is added into a button cell.

[0215] Example 19: The electrolyte composition of this example is base B + 3% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 5 + 3% FEC. The electrolyte prepared above is added into a button cell.

[0216] Example 20: The electrolyte composition of this example is base B + 3% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 5. The electrolyte prepared above is added into a button cell.

[0217] Example 21: The electrolyte composition of this example is baseA+5% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 7+1% FEC. The electrolyte prepared above is added into a button cell.

[0218] Example 22: The electrolyte composition of this example is baseA + 5% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 7. The electrolyte prepared above is added into a button cell.

[0219] Example 23: The electrolyte composition of this example is base B + 10% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 8 + 8% FEC. The electrolyte prepared above is added into a button cell.

[0220] Example 24: The electrolyte composition of this example is base B + 10% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 8. The electrolyte prepared above is added into a button cell.

[0221] Example 25: The electrolyte composition of this example is baseA + 15% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 10 + 5% FEC. The electrolyte prepared above is added into a button cell.

[0222] Example 26: The electrolyte composition of this example is baseA + 15% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 10. The electrolyte prepared above is added into a button cell.

[0223] Example 27: The electrolyte composition of this example is base B + 20% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 11 + 3% FEC. The electrolyte prepared above is added into a button cell.

[0224] Example 28: The electrolyte composition of this example is base B + 20% phosphorus-containing compound (phosphorus-containing electrolyte additive) No. 11. The electrolyte prepared above is added into a button cell.

[0225] Comparative Example 1

[0226] The electrolyte composition is baseA+3% FEC. The electrolyte prepared above is added into the button cell.

[0227] Comparative Example 2

[0228] The electrolyte composition is base A. The electrolyte prepared above is added into the button cell.

[0229] Comparative Example 3

[0230] The electrolyte composition is baseB+3% FEC. The electrolyte prepared above is added into the button cell.

[0231] Comparative Example 4

[0232] The electrolyte composition is base B. The electrolyte prepared above is added into the button cell.

[0233] The batteries prepared in Examples 13-28 and Comparative Examples 1-4 were subjected to cycle performance tests at room temperature, and the test results are shown in Table 1-2. The test process is as follows: 0.1C constant current charging to 4.5V, 0.1C constant current discharging to 2.8V, 3 cycles, 0.5C constant current charging to 4.5V, 0.5C constant current discharging to 2.8V, 200 cycles.

[0234] Table 1 (Lithium-ion battery)

[0235] Experiment number First coulombic efficiency (%) 0.5C Battery capacity retention after 200 cycles (%) Example 13 94.1 93.6 Embodiment 14 93.6 92.5 Embodiment 17 92.8 93.1 Embodiment 18 92.1 91.9 Embodiment 21 92.9 93.6 Embodiment 22 91.1 91.8 Embodiment 25 92.9 93.7 Embodiment 26 91.8 92.7 Comparative Example 1 89.7 85.4 Comparative Example 2 84.8 82.5

[0236] Table 2 (Sodium ion battery)

[0237] Experiment number First coulombic efficiency (%) 0.5C Battery capacity retention after 200 cycles (%) Embodiment 15 93.4 94.5 Example 16 88.1 92.3 Embodiment 19 91.6 92.3 Embodiment 20 86.7 91.5 Embodiment 23 91.6 92.2 Embodiment 24 86.9 91.5 Embodiment 27 90.8 91.9 Embodiment 28 86.7 91.1 Comparative Example 3 87.9 84.1 Comparative Example 4 83.5 81.9

[0238] It can be seen from the results of Table 1-2 that by comparing Examples 13-28 with Comparative Examples 1-4, by adding the phosphorus-containing compound of the present invention, the first coulombic efficiency and the capacity retention rate of the lithium battery or sodium battery in the 0.5C cycle test are greatly improved when the operating voltage is 4.5V. This is because the phosphorus-containing compound containing double bonds used in the present invention will undergo a polymerization reaction, be coated on the electrode, and form a protective film on the electrode of the battery, which has a protective effect on the electrode of the battery and has a positive effect on improving the high temperature cycle performance and stability performance of the lithium ion battery, thereby helping to extend the life of the battery and the safety of the battery operation.

[0239] When the phosphorus-containing compound of the present invention and fluoroethylene carbonate are added to a lithium battery or a sodium battery at the same time, the first coulombic efficiency of the battery is significantly improved compared with the lithium battery or the sodium battery to which only the phosphorus-containing compound of the present invention is added, indicating that when the phosphorus-containing compound of the present invention is used in combination with fluoroethylene carbonate, it has a significant advantage in improving the first efficiency of the lithium battery or the sodium battery. This is because the phosphorus-containing compound of the present invention and fluoroethylene carbonate can undergo a polymerization reaction when added to the electrolyte to participate in the formation of a CEI (Chemical-Electrochemical Interface) film, which reduces the irreversible capacity loss of the lithium battery or the sodium battery and improves the utilization rate of the positive electrode material. The CEI film also inhibits the decomposition of the electrolyte and reduces the electrochemical impedance of the battery, thereby improving the cycle stability of the lithium battery or the sodium battery.

[0240] The above are only a few optimal embodiments of the present application, and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the above disclosed technical content to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A phosphorus-containing compound, characterized in that The general structural formula is shown below: Wherein, R1, R2, R3, R4, R5, and R6 are independently selected from hydrogen atoms, C 1-12 Linear saturated hydrocarbon, C 1-12 Linear unsaturated hydrocarbon, aromatic, C 1-12 One of a silane 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, C 1-12 Linear unsaturated hydrocarbon, aromatic, C 1-12 The 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; The M + It is an alkali metal ion or a quaternary ammonium salt type cation.

2. The phosphorus-containing compound according to claim 1, characterized in that: R1, R2, R3, R4, R5, R6 are independently selected from hydrogen atoms, C 1-6 Linear saturated hydrocarbon, C 1-6 Linear unsaturated hydrocarbon, aromatic, C 1-6 One of a silane 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 1-6 Linear saturated hydrocarbon, C 1-6 Linear unsaturated hydrocarbon, aromatic, C 1-6 The 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; 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 phosphorus-containing compound according to claim 2, characterized in that: R1, R2, R3, R4, R5, R6 are independently selected from hydrogen atoms, C 1-4 Linear alkyl, C 1-4 Linear olefinic group, C 1-4 Linear alkynyl, aromatic, C 1-4 One of a silane 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 1-4 Linear alkyl, C 1-4 Linear olefinic group, C 1-4 Linear alkynyl, aromatic, C 1-4 The silyl group, allyloxy group, allyloxyalkyl group, saturated hydrocarbon group-containing acyloxy group, saturated hydrocarbon group-containing acyloxyalkyl group, unsaturated hydrocarbon group-containing acyloxy group and unsaturated hydrocarbon group-containing acyloxyalkyl group are each independently unsubstituted or substituted with a halogen element or a phenyl group.

4. The phosphorus-containing compound according to claim 3, characterized in that: The R1, R2, R3, R4, R5, and R6 are independently selected from a hydrogen atom, a methyl group, an ethyl group, a propyl group, an allyloxy group, an allyloxymethyl group, an acryloyloxy group, an acryloyloxymethyl group, an isoacryloyloxy group, an isoacryloyloxymethyl 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 isoallyl group, an allylic group, an isoallylic 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 phosphorus-containing compound according to claim 4, characterized in that: The structure is as follows:

6. The method for preparing the phosphorus-containing compound according to any one of claims 1 to 5, characterized in that: It is obtained by reacting a main raw material with hexafluorophosphate; the structural formula of the main raw material is Wherein, R1 and R2 are independently selected from hydrogen atoms, C 1-12 Linear saturated hydrocarbon, C 1-12 Linear unsaturated hydrocarbon, aromatic, C 1-12 One of a silane 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, C 1-12 Linear unsaturated hydrocarbon, aromatic, C 1-12 The 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; The hexafluorophosphate is selected from lithium hexafluorophosphate, sodium hexafluorophosphate, potassium hexafluorophosphate, tetramethylammonium hexafluorophosphate, and tetrabutylammonium hexafluorophosphate.

7. An electrolyte, characterized in that: Contains the phosphorus-containing compound according to any one of claims 1 to 5.

8. The electrolyte according to claim 7, characterized in that further comprising a lithium salt and an aprotic solvent, or further comprising a sodium salt and an aprotic solvent; Preferably, the lithium salt is at least one of lithium hexafluorophosphate, lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium difluorophosphate, lithium bis(trifluoromethanesulfonylimide) or lithium bis(fluorosulfonylimide); Preferably, the sodium salt is at least one of sodium hexafluorophosphate, sodium dioxalate borate, sodium difluorooxalate 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 phosphorus-containing compound in the electrolyte is 0.5-20%; the molar concentration of the alkali metal salt in the electrolyte is 1-2 mol / L.

9. The electrolyte according to claim 7 or 8, characterized in that: Also included are fluoroethylene carbonates; Preferably, the mass concentration of fluoroethylene carbonate in the electrolyte is 1-8%.

10. A secondary battery, characterized in that: Contains the phosphorus-containing compound according to any one of claims 1 to 5; and / or contains the electrolyte according to any one of claims 7 to 9.

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