Tetraoxa-silicon spiro compound and preparation method thereof, and application of tetraoxa-silicon spiro compound in secondary battery

Abstract

The invention discloses a tetra-oxa-silicon spiro compound and a preparation method thereof, and application of the tetra-oxa-silicon spiro compound in a secondary battery. The tetra-oxa-silicon spiro compound is a compound A as shown in a structural formula 1. The preparation method of the tetra-oxa-silicon spiro compound comprises the following steps: mixing a bis (trimethylsilyl) diester compound as shown in a formula 2 and a first solvent to form a first mixed solution; cooling the first mixed solution; dropwise adding silicon tetrachloride into the first mixed solution, carrying out a heating reaction in an inert atmosphere, and monitoring a reaction endpoint in the reaction process to obtain a crude product after the reaction is finished; mixing the crude product with a second solvent, pulping and purifying; the preparation method is simple to operate, the yield of the target product is high, and meanwhile, the tetra-oxa-silicon spiro compound has a good application prospect and can be applied to a secondary battery. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of material synthesis, and in particular relates to a tetraoxasilicon spiro compound and a preparation method thereof, and application in secondary batteries. Background Art

[0002] The advancement of lithium-ion battery technology has greatly promoted the development of modern electronic devices and electric vehicles, but to meet higher performance requirements, it is necessary to continuously optimize various battery indicators. Among them, the electrolyte, as a medium for ion transmission within the battery, has a crucial impact on the overall performance of the battery. In recent years, researchers have begun to focus on the application of organosilicon compounds as electrolyte additives, hoping to improve the performance of lithium-ion batteries through the unique properties of these compounds.

[0003] Organosilicon compounds are a large class of compounds that contain at least one silicon-carbon bond in their molecules, and the silicon atom can also be connected to various elements such as oxygen, nitrogen, and halogens. This diverse molecular structure allows scientists to design organosilicon compounds with different physical and chemical properties by changing the substituent groups on silicon. Currently commercialized silicon-based compounds include tris(trimethylsilyl)phosphate (TMSP) and polydimethylsiloxane (PDMS). However, with the development needs of power batteries and large-scale energy storage devices, existing silicon-based compounds still have deficiencies in certain performance aspects, and these deficiencies have gradually become bottleneck problems in lithium battery technology. Therefore, the development of a new generation of silicon-based compounds with superior chemical and electrochemical stability has become a common goal of academia and industry. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a tetraoxasilane spiro compound and a preparation method, and application in secondary batteries. The preparation method is simple to operate and has a high yield of the target product. At the same time, the tetraoxasilane spiro compound has good application prospects and can be used in secondary batteries.

[0005] To achieve the above objectives, the first aspect of the present invention provides a tetraoxasilane spiro compound, which is a compound A shown in structural formula 1:

[0006]

[0007] Wherein M is selected from O=S=O or C=O, and R is selected from CH2, CHF or CF2.

[0008] The core structure of the tetraoxasilicon spiro compound of the present invention is a spiro structure formed by two rings connected by a silicon atom and four oxygen atoms, which provides higher thermal stability and chemical stability; at the same time, each ring contains a carboxylate or disulfonate structure, and the introduction of these polar groups not only improves the solubility of the compound, but also enhances its electrochemical performance. Therefore, the tetraoxasilicon spiro compound of the present invention has a series of excellent physical and chemical properties, so that it has broad application prospects in the field of secondary batteries.

[0009] Furthermore, the compound A of the present invention is at least one selected from compounds 1 to 3:

[0010]

[0011] Accordingly, the second aspect of the present invention also provides a method for preparing the above-mentioned tetraoxasilane spiro compound, the steps comprising:

[0012] (1) mixing a bis(trimethylsilyl) diester compound represented by Formula 2 and a first solvent to form a first mixed solution;

[0013] (2) cooling the first mixed solution;

[0014] (3) adding silicon tetrachloride dropwise to the cooled first mixed solution, heating the solution under an inert atmosphere for reaction and monitoring the reaction endpoint during the reaction, and obtaining a crude product after the reaction is completed;

[0015] (4) mixing the crude product with a second solvent to obtain a second mixed solution, and then slurrying and purifying the second mixed solution;

[0016]

[0017] Wherein, M is selected from O=S=O or C=O, R is selected from CH2, CHF or CF2, and TMS is selected from (CH3)3Si.

[0018] The present invention reacts a bis(trimethylsilyl) diester compound with silicon tetrachloride and purifies it by pulping to obtain a tetraoxasilicon spiro compound with high yield; the trimethylchlorosilane reaction byproduct generated by the reaction has good volatility and is easily removed from the reaction system, which not only promotes the reaction to proceed in the forward direction, but also simplifies the purification process. Moreover, the byproduct trimethylchlorosilane is a commonly used chemical raw material with high economic value. Therefore, the preparation method of the present invention has easy raw materials, high yield of target product, high safety, simple operation, easy removal of byproducts and high economic value, and is suitable for large-scale industrial production.

[0019] Further, the mass ratio of the bis(trimethylsilyl) diester compound of the present invention to the first solvent is 1:5 to 10. Specifically, the mass ratio of the bis(trimethylsilyl) diester compound to the first solvent may be, but is not limited to, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10.

[0020] Further, the boiling point of the first solvent of the present invention is less than 100 ° C, that is, the first solvent of the present invention is a low boiling point solvent. Specifically, the first solvent includes at least one of nitriles, halogenated hydrocarbons, ethers, esters and ketones. More specifically, nitriles are acetonitrile or butyronitrile, halogenated hydrocarbons are dichloromethane, trichloromethane, 1,2-dichloroethane or tetrachloroethane, ethers are methyl tert-butyl ether, ethylene glycol dimethyl ether, tetrahydrofuran or dioxane, esters are dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl acetate, ethyl acetate or propyl acetate, and ketones are acetone, cyclohexanone or 4-methyl-2-pentanone. Preferably, the first solvent of the present invention is acetonitrile, ether or dichloromethane.

[0021] Furthermore, step (2) of the present invention includes cooling the first mixed solution to -20 to 10°C, such as -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 8°C, 10°C, etc.

[0022] Further, the molar ratio of the bis(trimethylsilyl) diester compound to silicon tetrachloride of the present invention is 1:0.45 to 0.5. Specifically, the molar ratio of the bis(trimethylsilyl) diester compound to silicon tetrachloride may be, but is not limited to, 1:0.45, 1:0.46, 1:0.47, 1:0.48, 1:0.49, 1:0.5.

[0023] Further, the dropwise addition time of silicon tetrachloride of the present invention is 0.5 to 2.5 hours. Specifically, the dropwise addition time of silicon tetrachloride can be, but is not limited to, 0.5 hours, 1 hour, 1.5 hours, 2 hours, or 2.5 hours.

[0024] Furthermore, the heating reaction in step (3) of the present invention comprises: reacting at room temperature for 2 to 3 hours. Specifically, room temperature refers to 15 to 35°C, and further 22 to 28°C.

[0025] Furthermore, in step (3) of the present invention, monitoring the reaction endpoint includes: monitoring the acid value content of the reaction system, and the reaction is terminated when the acid value content is 800 to 1300 ppm.

[0026] Furthermore, in step (4) of the present invention, the mass ratio of the crude product to the second solvent is 1:3 to 5; for example, the mass ratio of the crude product to the second solvent may be, but is not limited to, 1:3, 1:4, or 1:5.

[0027] Further, the second solvent of the present invention is an ester, a halogenated hydrocarbon or an ether solvent. Specifically, the second solvent is an ester, a halogenated hydrocarbon or an ether; more specifically, the ester is dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl acetate, ethyl acetate or propyl acetate, the halogenated hydrocarbon is dichloromethane, chloroform, 1,2-dichloroethane or tetrachloroethane, and the ether is diethyl ether, methyl tert-butyl ether, ethylene glycol dimethyl ether, tetrahydrofuran or dioxane. Preferably, the second solvent is ethyl acetate, dichloromethane or dichloroethane.

[0028] Furthermore, the time for pulping and purification in step (4) of the present invention is 0.5 to 5 hours. For example, the time for pulping and purification can be, but is not limited to, 0.5 hours, 1.0 hours, 1.5 hours, 2 hours, 3 hours, 4 hours, and 5 hours.

[0029] Accordingly, the third aspect of the present invention provides the use of the above-mentioned tetraoxasilicon spiro compound in a secondary battery. The tetraoxasilicon spiro compound can improve the electrochemical properties (such as cycle performance, etc.) of the secondary battery and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the tetraoxasilane spiro compound prepared in Example 1.

[0031] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the tetraoxasilane spiro compound prepared in Example 2.

[0032] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the tetraoxasilane spiro compound prepared in Example 3. DETAILED DESCRIPTION

[0033] In order to better illustrate the purpose, technical scheme and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of the present invention and should not be used as a limitation of the present invention.

[0034] The bis(trimethylsilyl) diester compound used in the present invention can be prepared by the following method:

[0035] The dibasic acid is added to a tetrahydrofuran solution, and then 2.2 moles of trimethylsilyl chloride are added at 0°C. After heating to room temperature, the mixture is stirred for 30 minutes. Then, 2.2 moles of an acid-binding agent triethylamine are slowly added, and the mixture is stirred for 1 hour and filtered. The solvent is evaporated and then distilled under reduced pressure to obtain a bis(trimethylsilyl) diester compound. Correspondingly, bis(trimethylsilyl) methyl disulfonic acid (CAS No.: 503-40-2) can be used as a dibasic acid to obtain bis(trimethylsilyl) methyl disulfonic acid ester; bis(trimethylsilyl) fluoromalonic acid (CAS No.: 473-87-0) can be used as a dibasic acid to obtain bis(trimethylsilyl) fluoromalonic acid ester; and bis(trimethylsilyl) malonate can be obtained by using malonic acid (CAS No.: 141-82-2).

[0036] Example 1

[0037] This embodiment provides a compound 1, and its preparation method comprises the following steps:

[0038] (1) adding 5 kg of bis(trimethylsilyl)methyl disulfonate and 50 kg of acetonitrile into a reaction kettle and stirring to mix evenly to obtain a first mixed solution;

[0039] (2) cooling the first mixed solution to 0° C.;

[0040] (3) 1.33 kg of silicon tetrachloride was added dropwise to the cooled first mixed solution within 1 hour. After the addition was completed, the temperature of the first mixed solution was raised to room temperature, nitrogen was continuously introduced, and the reaction was stirred for 2 hours. When the acid value was 1250 ppm after sampling, the reaction was stopped and filtered to obtain 4.8 kg of a crude white solid product;

[0041] (4) The crude product obtained in step (3) was mixed with 15 kg of ethyl acetate to obtain a second mixed solution, and the second mixed solution was stirred and slurried for 2 h. After filtering, it was vacuum dried to obtain 2.31 kg of compound 1, and its yield was 78.65%.

[0042] The preparation reaction equation of compound 1 in this example is as follows:

[0043]

[0044] The hydrogen nuclear magnetic resonance spectrum of the tetraoxasilane spirocyclic compound prepared in Example 1 is as follows: Figure 1 As shown, the spectrum confirmed the successful synthesis of compound 1.

[0045] Example 2

[0046] This embodiment provides a compound 2, and its preparation method comprises the following steps:

[0047] (1) adding 3.5 kg of bis(trimethylsilyl)fluoromalonate and 40 kg of dichloromethane into a reaction kettle and stirring to mix evenly to obtain a first mixed solution;

[0048] (2) cooling the first mixed solution to -10°C;

[0049] (3) 1.0 kg of silicon tetrachloride was added dropwise to the cooled first mixed solution within 0.5 h. After the addition was completed, the temperature of the first mixed solution was raised to room temperature, nitrogen was continuously introduced, and the reaction was stirred for 2 h. When the acid value was 1170 ppm after sampling, the reaction was stopped and filtered to obtain 1.2 kg of a crude white solid product;

[0050] (4) The crude product obtained in step (3) was mixed with 5 kg of dichloromethane to obtain a second mixed solution, and the second mixed solution was stirred and slurried for 2 h. After filtering, it was vacuum dried to obtain 1.09 kg of compound 2, with a yield of 62%.

[0051] The preparation reaction equation of compound 2 is shown below:

[0052]

[0053] The hydrogen nuclear magnetic resonance spectrum of the tetraoxasilane spirocyclic compound prepared in Example 2 is as follows: Figure 2 As shown, the spectrum confirmed the successful synthesis of compound 2.

[0054] Example 3

[0055] This embodiment provides a compound 3, and its preparation method comprises the following steps:

[0056] (1) adding 1.2 kg of bis(trimethylsilyl)malonate and 10 kg of dichloromethane into a reaction kettle and stirring to mix evenly to obtain a first mixed solution;

[0057] (2) cooling the first mixed solution to 0° C.;

[0058] (3) 0.4 kg of silicon tetrachloride was added dropwise to the cooled first mixed solution within 1 hour. After the addition was completed, the temperature of the first mixed solution was raised to room temperature, nitrogen was continuously introduced, and the reaction was stirred for 2 hours. When the acid value was 850 ppm after sampling, the reaction was stopped and filtered to obtain 0.45 kg of a crude white solid product;

[0059] (4) The crude product obtained in step (3) was mixed with 2 kg of ethyl acetate to obtain a second mixed solution, and the second mixed solution was stirred and slurried for 2 h. After filtering, it was vacuum dried to obtain 0.34 kg of compound 3, with a yield of 60%.

[0060] The preparation reaction equation of compound 3 is shown below:

[0061]

[0062] The hydrogen nuclear magnetic resonance spectrum of the tetraoxasilane spirocyclic compound prepared in Example 3 is as follows: Figure 3 As shown, the spectrum confirmed the successful synthesis of compound 3.

[0063] 1 g of compound 1 to compound 3 prepared in Examples 1 to 3 and 87 g of non-aqueous organic solvent (ethylene carbonate EC and ethyl methyl carbonate EMC in a mass ratio of 3:7) were respectively mixed evenly, and then 12 g of lithium hexafluorophosphate LiPF6 was added and mixed evenly to prepare non-aqueous electrolyte solutions 1# to 3#.

[0064] 88 g of non-aqueous organic solvent (ethylene carbonate EC, ethyl methyl carbonate EMC according to a mass ratio of 3:7) and 12 g of lithium hexafluorophosphate LiPF6 were mixed evenly to prepare non-aqueous electrolyte 4#.

[0065] Lithium cobalt oxide was used as the positive electrode material and lithium metal was used as the counter electrode. Non-aqueous electrolytes 1# to 4# were injected respectively to assemble button batteries 1# to 4#. At room temperature (25°C), the button batteries were charged and discharged at 3.0C / 3.0C (the battery discharge capacity was recorded as C0), the upper limit voltage was 4.1V, and then 3.0C / 3.0C was charged and discharged for 300 weeks, and the capacity retention rate was calculated.

[0066] Capacity retention rate = (battery capacity C1 after 300 cycles / battery initial capacity C0) * 100%

[0067] Table 1 Electrochemical performance test results

[0068]

[0069] From the results in Table 1, it can be seen that the cycle performance of button batteries 1 to 3# is better than that of button battery 4#. This is because the electrolyte of button batteries 1 to 3# contains the tetraoxasilicon spiro compound of the present application, which helps to improve the cycle performance of the battery.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A tetraoxasilicon spiro compound, characterized in that: Compound A is shown in structural formula 1: Wherein M is selected from O=S=O or C=O, and R is selected from CH2, CHF or CF2.

2. The tetraoxasilicon spiro compound according to claim 1, characterized in that The compound A is selected from at least one of compounds 1 to 3:

3. A method for preparing a tetraoxasilane spiro compound according to any one of claims 1 to 2, characterized in that the steps include: (1) mixing a bis(trimethylsilyl) diester compound represented by Formula 2 and a first solvent to form a first mixed solution; (2) cooling the first mixed solution; (3) adding silicon tetrachloride dropwise to the first mixed solution after cooling, heating the solution under an inert atmosphere for reaction and monitoring the reaction endpoint during the reaction, and obtaining a crude product after the reaction is completed; (4) mixing the crude product with a second solvent to obtain a second mixed solution, and then slurrying and purifying the second mixed solution; Wherein, M is selected from O=S=O or C=O, R is selected from CH2, CHF or CF2, and TMS is selected from (CH3)3Si.

4. The method for preparing a tetraoxasilane spiro compound according to claim 3, characterized in that: The mass ratio of the bis(trimethylsilyl) diester compound to the first solvent is 1:5-10, and the boiling point of the first solvent is less than 100°C.

5. The method for preparing the tetraoxasilane spiro compound according to claim 3, characterized in that: Step (2) comprises cooling the first mixed solution to -20 to 10°C.

6. The method for preparing a tetraoxasilane spiro compound according to claim 3, characterized in that: The molar ratio of the bis(trimethylsilyl) diester compound to silicon tetrachloride is 1:0.45-0.

5.

7. The method for preparing a tetraoxasilane spiro compound according to claim 3, characterized in that: The heating reaction in step (3) comprises: carrying out the reaction at room temperature for 2 to 3 hours.

8. The method for preparing a tetraoxasilane spiro compound according to claim 3, characterized in that: The monitoring of the reaction endpoint in step (3) includes: monitoring the acid value content of the reaction system by sampling titration method, and the reaction is terminated when the acid value content is 800-1300 ppm.

9. The method for preparing a tetraoxasilane spiro compound according to claim 3, characterized in that: In step (4), the mass ratio of the crude product to the second solvent is 1:3-5; the second solvent is an ester, halogenated hydrocarbon or ether solvent.

10. Use of the tetraoxasilicon spiro compound according to any one of claims 1 to 2 or the tetraoxasilicon spiro compound prepared by the method for preparing the tetraoxasilicon spiro compound according to any one of claims 3 to 9 in a secondary battery.

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