Tetraoxasilane spiro compound and preparation method thereof, and application in secondary battery

Abstract

The present invention discloses a tetraoxasilane spiro compound, a preparation method, and an application in secondary batteries. The tetraoxasilane spiro compound is compound A shown in structural formula 1. The preparation method of the tetraoxasilane spiro compound comprises the following steps: mixing a bis(trimethylsilyl) diester compound shown in formula 2 and a first solvent to form a first mixed solution; cooling the first mixed solution; adding silicon tetrachloride dropwise to the first mixed solution, heating the mixture under an inert atmosphere to react and monitoring the reaction endpoint during the reaction, and obtaining a crude product after the reaction is completed; mixing the crude product with a second solvent and slurrying and purifying the mixture. The preparation method is simple to operate and has a high yield of the target product. The tetraoxasilane spiro compound has good application prospects and can be used in secondary batteries. #imgabs0#

Description

Technical Field

[0001] The present 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] Advances in lithium-ion battery technology have greatly facilitated the development of modern electronic devices and electric vehicles. However, to meet ever-higher performance demands, continuous optimization of various battery specifications is required. The electrolyte, as the medium for ion transport within the battery, has a crucial impact on the battery's overall performance. In recent years, researchers have begun to focus on the use of organosilicon compounds as electrolyte additives, hoping to leverage these compounds' unique properties to improve lithium-ion battery performance.

[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 demand 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 excellent 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, as well as 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 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 composed of two rings connected by a silicon atom and four oxygen atoms, which provides high thermal and chemical stability. At the same time, each ring contains a carboxylate or disulfonate structure. 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, giving it broad application prospects in the field of secondary batteries.

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

[0010]

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

[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 beating 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 the compound by beating to obtain a tetraoxasilane spiro compound with a 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-to-obtain raw materials, high target product yield, high safety, simple operation, easy removal of byproducts and high economic value, and is suitable for large-scale industrial production.

[0019] Furthermore, 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 can be, but is not limited to, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10.

[0020] Furthermore, 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, the nitrile is acetonitrile or butyronitrile, the halogenated hydrocarbons are dichloromethane, chloroform, 1,2-dichloroethane or tetrachloroethane, the ethers are methyl tert-butyl ether, ethylene glycol dimethyl ether, tetrahydrofuran or dioxane, the esters are dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl acetate, ethyl acetate or propyl acetate, and the ketones are acetone, cyclohexanone or 4-methyl-2-pentanone. Preferably, the first solvent of the present invention is acetonitrile, diethyl 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] Furthermore, the molar ratio of the bis(trimethylsilyl) diester compound of the present invention to silicon tetrachloride is 1:0.45 to 0.5. Specifically, the molar ratio of the bis(trimethylsilyl) diester compound to silicon tetrachloride can be, but is not limited to, 1:0.45, 1:0.46, 1:0.47, 1:0.48, 1:0.49, or 1:0.5.

[0023] Furthermore, the silicon tetrachloride of the present invention is added dropwise for 0.5 to 2.5 hours. Specifically, the silicon tetrachloride addition time 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: carrying out the reaction 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, monitoring the reaction endpoint in step (3) of the present invention includes: monitoring the acid value content of the reaction system, and terminating the reaction 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] Furthermore, 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 beating and purification in step (4) of the present invention is 0.5 to 5 hours. For example, the time for beating and purification can be, but is not limited to, 0.5 hours, 1.0 hours, 1.5 hours, 2 hours, 3 hours, 4 hours, or 5 hours.

[0029] Accordingly, the third aspect of the present invention provides the use of the aforementioned tetraoxasilane spiro compound in a secondary battery. The tetraoxasilane spiro compound can improve the electrochemical properties (such as cycle performance) 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 solutions 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] A dibasic acid is added to a tetrahydrofuran solution, and then 2.2 moles of trimethylsilyl chloride is added at 0°C. The temperature is raised to room temperature and stirred for 30 minutes. Then, 2.2 moles of an acid-binding agent, triethylamine, is 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 the dibasic acid to obtain bis(trimethylsilyl) methyl disulfonate; bis(trimethylsilyl) fluoromalonate can be obtained by using fluoromalonic acid (CAS No.: 473-87-0) as the dibasic acid; and bis(trimethylsilyl) malonate can be obtained by using malonic acid (CAS No.: 141-82-2) as the dibasic acid.

[0036] Example 1

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

[0038] (1) adding 5 kg of bis(trimethylsilyl)methane disulfonate and 50 kg of acetonitrile into a reaction kettle and stirring and mixing them uniformly 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 over 1 hour. After the addition was complete, 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 and determination, the reaction was stopped and filtered to obtain 4.8 kg of a crude product as a white solid;

[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, with a yield of 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 spiro 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, the preparation method of which 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 uniformly 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 over 0.5 h. After the addition was complete, 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 of the sample was 1170 ppm, the reaction was stopped and filtered to obtain 1.2 kg of a crude product as a white solid;

[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 spiro 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, the preparation method of which 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 and mixing 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 and determination, the reaction was stopped and filtered to obtain 0.45 kg of a crude product as a white solid;

[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 spiro 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 mixed uniformly, and then 12 g of lithium hexafluorophosphate LiPF6 was added and mixed uniformly 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 uniformly to prepare non-aqueous electrolyte 4#.

[0065] Lithium cobalt oxide was used as the positive electrode material and lithium metal as the counter electrode. 1# to 4# button cells were injected with non-aqueous electrolytes. At room temperature (25°C), the button cells were charged and discharged once at a 3.0C / 3.0C rate (the battery discharge capacity is recorded as C0) with an upper voltage of 4.1V. The cells were then charged and discharged at a 3.0C / 3.0C rate for 300 cycles, and the capacity retention 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 solutions 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 solutions of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a tetraoxasilane spiro compound, 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 to -20 to 10°C; (3) adding silicon tetrachloride dropwise to the cooled first mixed solution, heating the solution under an inert atmosphere to react and monitoring the reaction endpoint during the reaction, and obtaining a crude product after the reaction is completed, wherein the heating reaction comprises: reacting at room temperature for 2 to 3 hours; (4) mixing the crude product with a second solvent to obtain a second mixed solution, and then beating and purifying the second mixed solution to obtain a tetraoxasilane spiro compound; 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; the tetraoxasilane spiro compound is compound A 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 method for preparing a tetraoxasilane spiro compound according to claim 1, wherein The compound A is selected from at least one of compounds 1 to 3:

3. The method for preparing a tetraoxasilane spiro compound according to claim 1, wherein 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.

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

5.

5. The method for preparing a tetraoxasilane spiro compound according to claim 1, wherein The monitoring of the reaction endpoint in step (3) includes: monitoring the acid value content of the reaction system by sampling titration, and the reaction is terminated when the acid value content is 800-1300 ppm.

6. The method for preparing a tetraoxasilane spiro compound according to claim 1, wherein The mass ratio of the crude product to the second solvent in step (4) is 1:3-5; the second solvent is an ester, halogenated hydrocarbon or ether solvent. 7 . Use of the tetraoxasilicon spiro compound prepared by the method for preparing the tetraoxasilicon spiro compound according to claim 1 in a secondary battery.

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