Preparation method and application of tris (cyanoalkyl) phosphate compound
Through the one-step reaction in the presence of a solvent and a catalyst, the reaction conditions are optimized, and the tri(cyanoalkyl) phosphate compounds with high purity and high yield are prepared, which solves the problem of insufficient product yield and purity in the prior art. It is suitable for lithium battery electrolyte additives and improves battery performance.
Patent Information
- Application Number
- CN202510501048.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-21
- Publication Date
- 2025-07-18
AI Technical Summary
In the prior art, the preparation method of tri(2-cyanoethyl) phosphate has problems with insufficient product yield and purity, which is difficult to meet the needs of improving lithium battery performance.
Tris(cyanoalkyl)phosphate compounds are prepared by a one-step reaction using solvents and catalysts. The specific steps include mixing, reaction, filtration, washing and distillation of phosphate compounds and alkenyl cyano compounds, and optimizing reaction conditions such as temperature, pressure and time to improve selectivity and product purity.
It achieves high purity and high yield of tri(cyanoalkyl) phosphate compounds, is suitable for industrial production, reduces costs and improves the performance of lithium batteries.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electrolyte additives, and particularly relates to a preparation method and application of a tris(cyanoalkyl) phosphate compound. Background Art
[0002] As an important part of modern energy storage, the performance improvement of lithium batteries is closely related to the optimization of battery materials. During the manufacturing process of lithium batteries, the use of additives can effectively improve the performance and safety of the batteries. Among them, phosphate esters and nitrile additives are two important types of battery additives, which are widely used in the electrolytes of lithium batteries.
[0003] Phosphate ester additives are mainly used in lithium batteries to improve the performance of electrolytes. They have the following significant advantages: 1. High conductivity: Phosphate ester additives can increase the ionic conductivity of electrolytes, thereby improving the charge and discharge efficiency of batteries. This is particularly important for high-power applications (such as electric vehicles). 2. Thermal stability: Phosphate esters have good thermal stability, can maintain the stability of electrolytes in high-temperature environments, reduce the risk of thermal runaway, and improve the safety of batteries. 3. Improve interface stability: Phosphate esters can form a stable solid electrolyte interface (SEI) on the electrode surface, which helps to inhibit the deposition of lithium metal and improve the cycle life and efficiency of lithium batteries. 4. Compatibility: Phosphate esters have good compatibility with common organic solvents, can form homogeneous electrolytes with various lithium salts, and meet the requirements of different types of lithium batteries.
[0004] The application of nitrile compounds in lithium batteries mainly focuses on improving the electrochemical performance and safety of the batteries. Their main characteristics include: 1. Improve high-temperature performance: Nitrile additives have good thermal stability, can effectively improve the stability of electrolytes under high-temperature conditions, and reduce the decomposition of electrolytes caused by temperature increase. 2. Enhance the energy density of lithium-ion batteries: Nitrile substances can improve the electrochemical window of batteries and enhance the energy density of batteries, making lithium batteries more advantageous in terms of volume and weight, and suitable for fields such as portable electronic devices and electric vehicles. 3. Improve the cycle stability of batteries: Nitrile additives can effectively reduce the degradation of electrode materials in electrolytes, extend the service life of batteries, and improve the cycle stability. 4. Reduce the self-discharge rate of batteries: The addition of nitrile additives can effectively reduce the self-discharge phenomenon of batteries and improve the energy retention rate during storage.
[0005] In summary, the application of phosphate esters and nitrile additives in lithium batteries has greatly promoted the development of battery technology. By improving the performance of the electrolyte and enhancing the safety and service life of the battery, they have laid the foundation for the wide application of lithium batteries. However, with the gradual increase in the performance requirements of lithium-ion batteries in downstream application industries, it is necessary to further develop phosphate esters and nitrile additives with better performance. For example, tris(2-cyanoethyl) phosphate has the advantages of both nitrile additives and phosphate ester additives. However, at present, the product yield and purity obtained by the preparation method of tris(2-cyanoethyl) phosphate need to be further improved.
[0006] Therefore, developing a preparation method for tris(2-cyanoethyl) phosphate with high yield, high purity, and good selectivity is an urgent problem to be solved in this field. Summary of the Invention
[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a preparation method and application of tris(cyanoalkyl) phosphate compounds. The preparation method has high selectivity, and the obtained product has high purity, high yield, simple process, and is suitable for large-scale production.
[0008] To achieve this purpose, the present invention adopts the following technical solutions:
[0009] In the first aspect, the present invention provides a preparation method of tris(cyanoalkyl) phosphate compounds, which comprises the following steps: reacting a phosphoric acid compound with an alkenyl cyanide compound in the presence of a solvent and a catalyst to obtain the tris(cyanoalkyl) phosphate compound.
[0010] In the present invention, the preparation method uses a phosphoric acid compound and an alkenyl cyanide compound as raw materials to prepare tris(cyanoalkyl) phosphate compounds in one step in the presence of a solvent and a catalyst. It has high selectivity, and the obtained tris(cyanoalkyl) phosphate compounds have high purity, high yield, simple process, low cost, and are suitable for industrial production.
[0011] Preferably, the solvent includes an aprotic organic solvent.
[0012] Preferably, the aprotic organic solvent includes any one or at least two combinations of dimethyl carbonate, acetonitrile, dichloromethane, dichloroethane, diethyl carbonate, or 1,4-dioxane; more preferably dimethyl carbonate and / or acetonitrile.
[0013] Preferably, the mass ratio of the phosphoric acid compound to the solvent is 1:(6 - 10), where the specific values in (6 - 10) can be, for example, 6, 6.2, 6.4, 6.6, 6.8, 7, 7.2, 7.4, 7.6, 7.8, 8, 8.2, 8.4, 8.6, 8.8, 9, 9.2, 9.4, 9.6, 9.8, 10, etc.; more preferably 1:(6.5 - 8).
[0014] Preferably, the catalyst includes a basic catalyst.
[0015] Preferably, the catalyst includes any one or a combination of at least two of 1,8 - diazabicyclo[5.4.0]undec - 7 - ene (DBU), triethylamine, potassium carbonate, potassium hydroxide, sodium hydroxide, sodium methoxide or sodium ethoxide, and is further preferably 1,8 - diazabicyclo[5.4.0]undec - 7 - ene and / or triethylamine.
[0016] Preferably, the mass ratio of the phosphoric acid compound to the catalyst is 1:(0.01 - 0.15), where the specific values in (0.01 - 0.15) can be, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, etc.; preferably 1:(0.05 - 0.1).
[0017] Preferably, the phosphoric acid compound includes phosphoric acid and / or phosphate.
[0018] Preferably, the phosphate includes any one or a combination of at least two of sodium phosphate, sodium hydrogen phosphate or sodium dihydrogen phosphate.
[0019] Preferably, the alkenyl cyanide compound includes any one or a combination of at least two of acrylonitrile, 2 - butenenitrile or 3 - butenenitrile.
[0020] Preferably, the molar ratio of the phosphoric acid compound to the alkenyl cyanide compound is 1:(3.0 - 4.2), where the specific values in (3.0 - 4.2) can be, for example, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, etc.; preferably 1:(3.2 - 3.6).
[0021] Preferably, the temperature of the reaction is 90 to 160 °C, for example, it can be 90 °C, 92 °C, 94 °C, 96 °C, 98 °C, 100 °C, 102 °C, 104 °C, 106 °C, 108 °C, 110 °C, 112 °C, 115 °C, 118 °C, 120 °C, 122 °C, 125 °C, 128 °C, 130 °C, 132 °C, 135 °C, 138 °C, 140 °C, 142 °C, 145 °C, 148 °C, 150 °C, 152 °C, 155 °C, 158 °C, 160 °C, etc.; preferably 100 to 130 °C.
[0022] Preferably, the reaction time is 2 to 8 h, for example, it can be 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, etc.; more preferably 3 to 6 h.
[0023] Preferably, the reaction pressure is 0.1 to 0.84 MPa, for example, it can be 0.1 MPa, 0.12 MPa, 0.15 MPa, 0.18 MPa, 0.2 MPa, 0.22 MPa, 0.25 MPa, 0.28 MPa, 0.3 MPa, 0.32 MPa, 0.35 MPa, 0.38 MPa, 0.4 MPa, 0.42 MPa, 0.45 MPa, 0.48 MPa, 0.5 MPa, 0.52 MPa, 0.55 MPa, 0.58 MPa, 0.6 MPa, 0.62 MPa, 0.65 MPa, 0.68 MPa, 0.7 MPa, 0.72 MPa, 0.75 MPa, 0.78 MPa, 0.8 MPa, 0.82 MPa, etc.; more preferably 0.15 to 0.42 MPa.
[0024] Preferably, after the reaction, it also includes steps of cooling down the temperature and reducing the pressure for post-treatment.
[0025] Preferably, the temperature is cooled down to room temperature (25 °C) and the pressure is reduced to atmospheric pressure.
[0026] Preferably, the post-treatment includes filtration, washing and rectification.
[0027] In the present invention, the filtration method includes suction filtration; the washing includes rinsing with deionized water.
[0028] Preferably, the rectification includes atmospheric rectification.
[0029] Preferably, the temperature of the rectification is 140 to 190 °C, for example, it can be 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, etc.; more preferably 160 to 180 °C.
[0030] As a preferred technical solution of the present invention, the preparation method comprises the following steps:
[0031] (1) Mix a phosphoric acid compound with an alkenyl cyanide compound, a solvent and a catalyst, and react at a temperature of 90-160 °C and a pressure of 0.1-0.84 MPa for 2-8 h. Then, lower the temperature of the system to room temperature and the pressure to atmospheric pressure to obtain a reaction solution; the mass ratio of the phosphoric acid compound to the solvent is 1:(6-10), the mass ratio of the phosphoric acid compound to the catalyst is 1:(0.01-0.15), and the molar ratio of the phosphoric acid compound to the alkenyl cyanide compound is 1:(3.0-4.2);
[0032] (2) Filter and wash the reaction solution obtained in step (1) to obtain a crude product solution;
[0033] (3) Distill the crude product solution obtained in step (2) at a temperature of 140-190 °C and atmospheric pressure to obtain the tris(cyanoalkyl) phosphate compound.
[0034] In the present invention, the alkyl group in the tris(cyanoalkyl) phosphate compound is a straight-chain or branched-chain alkyl group with a carbon atom number of ≥2; the alkenyl cyanide compound is selected from acrylonitrile, and the tris(cyanoalkyl) phosphate compound is a tris(2-cyanoethyl) phosphate compound; the structure is Its preparation route is as follows:
[0035]
[0036] In the second aspect, the present invention provides an application of a tris(cyanoalkyl) phosphate compound prepared by the preparation method according to the first aspect in a lithium battery.
[0037] Preferably, the tris(cyanoalkyl) phosphate compound is used as an additive for a lithium battery electrolyte.
[0038] The numerical ranges described in the present invention include not only the above-listed point values, but also any point values between the above numerical ranges not listed. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the ranges.
[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0040] The preparation method of the tris(cyanoalkyl) phosphate compound provided by the present invention uses a phosphoric acid compound and an alkenyl cyanide compound as raw materials in the presence of a solvent and a catalyst to prepare the tris(cyanoalkyl) phosphate compound by a one-step method, which has high selectivity, high purity and high yield of the obtained tris(cyanoalkyl) phosphate compound, and the process is simple, the cost is low, and it is suitable for industrial production. Detailed implementation manners
[0041] The technical solution of the present invention will be further described below through specific implementation manners. Those skilled in the art should understand that the embodiments are only to help understand the present invention and should not be regarded as specific limitations on the present invention.
[0042] Example 1
[0043] This example provides a preparation method of a tris(cyanoalkyl) phosphate compound, which specifically includes the following steps:
[0044] In a 1000 ml high-pressure reaction device, dimethyl carbonate (342.98 g, 3.8 mol), DBU (3.91 g, 0.025 mol), acrylonitrile (90.207 g, 1.7 mol), and phosphoric acid (48.99 g, 0.5 mol) are sequentially added, stirred evenly, heated to 120 °C, pressurized to 0.32 MPa, and kept warm for reaction for 4 h; the mass ratio of the phosphoric acid to the dimethyl carbonate is 1:7, and the molar ratio is 1:7.6; the mass ratio of the phosphoric acid to the DBU is 1:0.08, and the molar ratio is 1:0.05; the molar ratio of the phosphoric acid to the acrylonitrile is 1:3.4. When the holding reaction reaches the required reaction time, stop heating, slowly cool down to 25 °C to obtain a tris(2-cyanoethyl) phosphate reaction solution, filter the tris(2-cyanoethyl) phosphate reaction solution by suction, wash it with water, and separate the liquid to obtain crude tris(2-cyanoethyl) phosphate; then perform atmospheric distillation (temperature is 170 °C) on the crude tris(2-cyanoethyl) phosphate to obtain a finished product of tris(2-cyanoethyl) phosphate, that is, the tris(cyanoalkyl) phosphate compound is obtained.
[0045] Example 2
[0046] This example provides a preparation method of a tris(cyanoalkyl) phosphate compound, and the difference from Example 1 is only that DBU (3.91 g, 0.025 mol) is replaced by triethylamine (3.91 g, 0.038 mol), and the mass ratio of the phosphoric acid to the triethylamine is 1:0.08, and the molar ratio is 1:0.076; other raw materials, dosages, and process parameters are the same as those in Example 1.
[0047] Example 3
[0048] This example provides a preparation method of a tris(cyanoalkyl) phosphate compound, and the difference from Example 1 is only that the content of acrylonitrile is adjusted so that the molar ratio of the phosphoric acid to the acrylonitrile is 1:3.2, and other raw materials, dosages, and process parameters are the same as those in Example 1.
[0049] Example 4
[0050] This example provides a method for preparing a tris(cyanoalkyl) phosphate compound. The difference from Example 1 is only that the content of acrylonitrile is adjusted so that the molar ratio of phosphoric acid to acrylonitrile is 1:3.6, and the other raw materials, dosages, and process parameters are the same as those in Example 1.
[0051] Example 5
[0052] This example provides a method for preparing a tris(cyanoalkyl) phosphate compound. The difference from Example 1 is only that the content of DBU is adjusted so that the mass ratio of phosphoric acid to DBU is 1:0.05, and the molar ratio is 1:0.032, and the other raw materials, dosages, and process parameters are the same as those in Example 1.
[0053] Example 6
[0054] This example provides a method for preparing a tris(cyanoalkyl) phosphate compound. The difference from Example 1 is only that the content of DBU is adjusted so that the mass ratio of phosphoric acid to DBU is 1:0.1, and the molar ratio is 1:0.064, and the other raw materials, dosages, and process parameters are the same as those in Example 1.
[0055] Example 7
[0056] This example provides a method for preparing a tris(cyanoalkyl) phosphate compound. The difference from Example 1 is only that the temperature is raised to 100 °C, the pressure is increased by 0.19 MPa, and the reaction is carried out under insulation for 3 h, and the other raw materials, dosages, and process parameters are the same as those in Example 1.
[0057] Example 8
[0058] This example provides a method for preparing a tris(cyanoalkyl) phosphate compound. The difference from Example 1 is only that the temperature is raised to 130 °C, the pressure is increased by 0.42 MPa, and the reaction is carried out under insulation for 6 h, and the other raw materials, dosages, and process parameters are the same as those in Example 1.
[0059] Example 9
[0060] This example provides a method for preparing a tris(cyanoalkyl) phosphate compound. The difference from Example 1 is only that the temperature is raised to 130 °C, the pressure is increased by 0.42 MPa, and the reaction is carried out under insulation for 3 h, and the other raw materials, dosages, and process parameters are the same as those in Example 1.
[0061] Example 10
[0062] This example provides a method for preparing a tris(cyanoalkyl) phosphate compound. The difference from Example 1 is only that the temperature is raised to 100 °C, the pressure is increased by 0.19 MPa, and the reaction is carried out under insulation for 6 h, and the other raw materials, dosages, and process parameters are the same as those in Example 1.
[0063] Embodiment 11
[0064] This embodiment provides a method for preparing a tri(cyanoalkyl)phosphate compound, which differs from Example 1 only in that the content of acrylonitrile is adjusted so that the molar ratio of phosphoric acid to acrylonitrile is 1:3, and the content of dimethyl carbonate is adjusted so that the mass ratio of phosphoric acid to dimethyl carbonate is 1:6, and the molar ratio is 1:6.52. Other raw materials, amounts and process parameters are the same as those in Example 1.
[0065] Example 12
[0066] This embodiment provides a method for preparing a tris(cyanoalkyl)phosphate compound, which differs from Example 1 only in that the content of acrylonitrile is adjusted so that the molar ratio of phosphoric acid to acrylonitrile is 1:4.2, and the content of dimethyl carbonate is adjusted so that the mass ratio of phosphoric acid to dimethyl carbonate is 1:10 and the molar ratio is 1:10.86. Other raw materials, amounts and process parameters are the same as those in Example 1.
[0067] Example 13
[0068] This embodiment provides a method for preparing tris(cyanoalkyl)phosphate compounds, which differs from Example 1 only in that the temperature is raised to 90° C., the pressure is raised to 0.14 MPa, and the reaction is kept warm for 2 hours. Other raw materials, amounts and process parameters are the same as those in Example 1.
[0069] Embodiment 14
[0070] This embodiment provides a method for preparing tris(cyanoalkyl)phosphate compounds, which differs from Example 1 only in that the temperature is raised to 160° C., the pressure is raised to 0.84 MPa, and the reaction is kept warm for 8 hours. Other raw materials, amounts and process parameters are the same as those in Example 1.
[0071] Embodiment 15
[0072] This embodiment provides a method for preparing tris(cyanoalkyl)phosphate compounds, which differs from Example 1 only in that the temperature is raised to 160° C., the pressure is raised to 0.84 MPa, and the reaction is kept warm for 2 hours. Other raw materials, amounts, and process parameters are the same as those in Example 1.
[0073] Example 16
[0074] This embodiment provides a method for preparing tris(cyanoalkyl)phosphate compounds, which differs from Example 1 only in that the temperature is raised to 90° C., the pressure is raised to 0.14 MPa, and the reaction is kept warm for 8 hours. Other raw materials, amounts, and process parameters are the same as those in Example 1.
[0075] Embodiment 17
[0076] This example provides a method for preparing a tris(cyanoalkyl) phosphate compound. The difference from Example 1 is only that the content of DBU is adjusted so that the mass ratio of phosphoric acid to DBU is 1:0.01 and the molar ratio is 1:0.006, and other raw materials, dosages, and process parameters are the same as those in Example 1.
[0077] Example 18
[0078] This example provides a method for preparing a tris(cyanoalkyl) phosphate compound. The difference from Example 1 is only that the content of DBU is adjusted so that the mass ratio of phosphoric acid to DBU is 1:0.15 and the molar ratio is 1:0.096, and other raw materials, dosages, and process parameters are the same as those in Example 1.
[0079] Example 19
[0080] This example provides a method for preparing a tris(cyanoalkyl) phosphate compound. The difference from Example 1 is only that DBU is replaced with an equal mass of potassium hydroxide, and other raw materials, dosages, and process parameters are the same as those in Example 1.
[0081] Comparative Example 1
[0082] This comparative example provides a method for preparing a tris(cyanoalkyl) phosphate compound, including the following steps:
[0083] Add a mixture of 3-hydroxypropionitrile (71.08 g, 1.0 mol) and triethylamine (0.75 mol) to a 500 ml reaction kettle, dropwise add a mixture of phosphorus oxychloride (38.33 g, 0.25 mol) and xylene (250 ml) at 0 °C. After the addition is complete, add sodium ethoxide (1.70 g, 0.025 mol), then raise the temperature to 60 °C and react for 5 hours. After the reaction is completed, cool the reaction solution to room temperature, add xylene for extraction, filter, separate the liquid, and distill the filtrate under reduced pressure to obtain the product, that is, the tris(cyanoalkyl) phosphate compound is obtained.
[0084] The purity and total yield of the tris(cyanoalkyl) phosphate compounds obtained by the preparation methods provided in the examples and comparative examples were tested by gas chromatography (the instrument is Agilent 7890B), and the test results are shown in Table 1.
[0085] Table 1
[0086]
[0087]
[0088] As can be seen from Table 1, the purity of the tris(cyanoalkyl) phosphate compound obtained by the preparation method provided by the present invention is ≥99.9%, and the yield is ≥69.4 wt%, and even the effect of purity ≥99.95% and yield ≥80 wt% can be achieved; the product obtained by the preparation method has high purity, high yield, simple process and low cost; as can be seen from Examples 12, 14 and 18, increasing the raw material dosage or increasing the reaction temperature, pressure and time does not significantly improve the purity and yield, but will increase the production cost.
[0089] As can be seen from Comparative Example 1, compared with the tris(cyanoalkyl) phosphate compound prepared using 3-hydroxypropionitrile and phosphorus oxychloride as raw materials, the preparation method provided by the present invention has higher purity and yield.
[0090] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for preparing a tris(cyanoalkyl) phosphate compound, characterized in that, The preparation method comprises the following steps: In the presence of a solvent and a catalyst, a phosphoric acid compound is reacted with an alkenyl cyanide compound to obtain the tris(cyanoalkyl) phosphate compound.
2. The preparation method according to claim 1, characterized in that, The solvent includes an aprotic organic solvent; Preferably, the aprotic organic solvent includes any one or a combination of at least two of dimethyl carbonate, acetonitrile, dichloromethane, dichloroethane, diethyl carbonate or 1,4-dioxane; more preferably dimethyl carbonate and / or acetonitrile.
3. The preparation method according to claim 1 or 2, characterized in that, The mass ratio of the phosphoric acid compound to the solvent is 1:(6 - 10), preferably 1:(6.5 - 8).
4. The preparation method according to any one of claims 1 to 3, characterized in that, The catalyst includes a basic catalyst; Preferably, the catalyst includes any one or a combination of at least two of bicyclic amidine, triethylamine, potassium carbonate, potassium hydroxide, sodium hydroxide, sodium methoxide or sodium ethoxide, more preferably bicyclic amidine and / or triethylamine.
5. The preparation method according to any one of claims 1 to 4, characterized in that, The mass ratio of the phosphoric acid compound to the catalyst is 1:(0.01 - 0.15), preferably 1:(0.05 - 0.1).
6. The preparation method according to any one of claims 1 to 5, characterized in that, The phosphoric acid compound includes phosphoric acid and / or phosphate; Preferably, the phosphate includes any one or a combination of at least two of sodium phosphate, sodium hydrogen phosphate or sodium dihydrogen phosphate; Preferably, the alkenyl cyanide compound includes any one or a combination of at least two of acrylonitrile, 2-butenenitrile or 3-butenenitrile; Preferably, the molar ratio of the phosphoric acid compound to the alkenyl cyanide compound is 1:(3.0 - 4.2), preferably 1:(3.2 - 3.6).
7. The preparation method according to any one of claims 1 to 6, characterized in that, The temperature of the reaction is 90 - 160 °C, preferably 100 - 130 °C; Preferably, the reaction time is 2 - 8 h, more preferably 3 - 6 h; Preferably, the reaction pressure is 0.1 - 0.84 MPa, more preferably 0.15 - 0.42 MPa.
8. The preparation method according to any one of claims 1 to 7, characterized in that, After the reaction, it further includes the steps of cooling and depressurizing and then performing post-treatment; Preferably, the cooling is to room temperature and the depressurizing is to atmospheric pressure; Preferably, the post-treatment includes filtration, washing and rectification; Preferably, the rectification includes atmospheric rectification; Preferably, the temperature of the rectification is 140 - 190 °C.
9. The preparation method according to any one of claims 1 to 8, characterized in that, The preparation method comprises the following steps: (1) Mix a phosphoric acid compound, an alkenyl cyanide compound, a solvent and a catalyst, react at a temperature of 90 - 160 °C and a pressure of 0.1 - 0.84 MPa for 2 - 8 h, cool the system temperature to room temperature and the pressure to atmospheric pressure to obtain a reaction solution; the mass ratio of the phosphoric acid compound to the solvent is 1:(6 - 10), the mass ratio of the phosphoric acid compound to the catalyst is 1:(0.01 - 0.15), and the molar ratio of the phosphoric acid compound to the alkenyl cyanide compound is 1:(3.0 - 4.2); (2) Filter and wash the reaction solution obtained in step (1) to obtain a crude product solution; (3) Rectify the crude product solution obtained in step (2) at a temperature of 140 - 190 °C and atmospheric pressure to obtain the tris(cyanoalkyl) phosphate compound.
10. Use of a tris(cyanoalkyl) phosphate compound prepared by the preparation method according to any one of claims 1 to 9 in a lithium battery; Preferably, the tris(cyanoalkyl) phosphate compound is used as an additive for a lithium battery electrolyte.