A method for synthesizing a fluorinated bis-sulfonylimino lithium compound

Abstract

The application relates to the technical field of lithium battery electrolyte, and discloses a synthesis method of a fluorinated bis-sulfonylimino lithium compound, which comprises the following steps: S1: a substitution reaction of a compound I with ammonia gas under alkaline conditions to obtain an intermediate I; the compound I is a sulfonyl fluoride-perfluoroalkyl compound; and S2: a salt reaction of the intermediate I with lithium carbonate to obtain the fluorinated bis-sulfonylimino lithium compound. Through the technical scheme, the problems of low electrolyte performance of a lithium ion battery in the prior art are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium battery electrolyte, in particular to a synthesis method of fluorinated bis-sulfonylimino lithium compound. BACKGROUND

[0002] Lithium ion battery is widely used in people's daily life, and has important applications in many fields such as electronic products, electric vehicles, aerospace, etc. With the increasing prosperity of economic activities, higher performance and better safety lithium ion batteries are needed in production and life. Therefore, higher requirements are put forward for the performance of lithium ion batteries.

[0003] At present, the research on the performance improvement of lithium ion battery mainly focuses on the improvement of electrolyte. Fluorine is the element with the largest electrode polarity. The introduction of fluorine can make organic compounds have unique physical and chemical properties. Fluorinated bis-sulfonylimino lithium compound is a unique electrolyte. The introduction of fluorinated bis-sulfonylimino lithium compound as electrolyte into lithium ion battery can significantly improve its performance. SUMMARY

[0004] The present application provides a synthesis method of fluorinated bis-sulfonylimino lithium compound, which solves the problem of poor electrolyte performance of lithium ion battery in the prior art.

[0005] The technical scheme of the present application is as follows:

[0006] A synthesis method of fluorinated bis-sulfonylimino lithium compound, comprising the following steps:

[0007] S1: Compound I undergoes a substitution reaction with ammonia gas under alkaline conditions to obtain intermediate I; the compound I is a sulfonyl fluoride-perfluoroalkyl compound;

[0008] S2: Intermediate I reacts with lithium carbonate to form a salt reaction to obtain fluorinated bis-sulfonylimino lithium compound.

[0009] As a further technical scheme, the sulfonyl fluoride-perfluoroalkyl compound is perfluoroethanesulfonyl fluoride or 1,2-sulfonyl fluoride-perfluoroethane or 1,3-sulfonyl fluoride-perfluoropropane.

[0010] As a further technical scheme, the alkaline condition in the substitution reaction of step S1 is provided by an organic base;

[0011] The organic base is one of N,N-diisopropylethylamine, N,N-diisopropylmethylamine, dimethylisopropylamine, diethylisopropylamine, triethylamine and trimethylamine;

[0012] As a further technical scheme, the organic base is one of N,N-diisopropylethylamine, N,N-diisopropylmethylamine, dimethylisopropylamine and diethylisopropylamine.

[0013] As a further technical solution, in the substitution reaction of step S1, the molar ratio of nitrogen in ammonia to sulfur in compound I is 1:2-1:2.6.

[0014] As a further technical solution, in the substitution reaction of step S1, the molar ratio of sulfur in compound I to organic base is 1:1-1:2.

[0015] As a further technical solution, the substitution reaction of step S1 is carried out in a solvent, and the solvent is tetrahydrofuran.

[0016] As a further technical solution, in the substitution reaction of step S1, the reaction temperature is 50-60℃.

[0017] As a further technical solution, in the substitution reaction of step S1, the reaction time is 4-6h.

[0018] As a further technical solution, in the salt formation reaction of step S2, the molar ratio of lithium carbonate to compound I is 1:2-1.5:2.

[0019] As a further technical solution, the salt formation reaction of step S2 is carried out in a solvent, and the solvent is 1,4-dioxane.

[0020] As a further technical solution, in the salt formation reaction of step S2, the reaction temperature is 20-30℃.

[0021] As a further technical solution, in the salt formation reaction of step S2, the reaction time is 1-2h.

[0022] The application also provides the application of the fluorinated bis-sulfonylimino lithium compound prepared by the synthesis method in lithium battery electrolyte.

[0023] The working principle and beneficial effects of the application are as follows:

[0024] In the application, the fluorinated bis-sulfonylimino lithium compound is prepared by substitution reaction and salt formation reaction under alkaline conditions, using sulfuryl fluoride-perfluoroalkyl compound and ammonia as raw materials. The alkaline conditions are provided by organic amine, and the organic amine is a tertiary amine that does not react with the raw materials. The organic tertiary amine provides an alkaline environment for the reaction, and reacts with the generated hydrogen fluoride to prevent corrosion of the container by hydrogen fluoride and promote the reaction.

[0025] The fluorinated bis-sulfonylimino lithium compound prepared by the synthesis method is applied to lithium battery electrolyte, which significantly improves the thermal stability and high temperature resistance of the electrolyte, thereby improving the safety of lithium batteries at high temperatures. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0027] Embodiment 1

[0028] S1: In a 2000 mL three-necked flask, 1000 mL of tetrahydrofuran, (672.10 g, 5.20 mol) N,N-diisopropylethylamine were added, N2 was protected, stirring, (525.38 g, 2.60 mol) perfluoroethanesulfonyl fluoride was added, the temperature was controlled at 50 ℃, (22.4 L, 1.00 mol) ammonia was introduced, the reaction was carried out for 6 h, it was cooled to room temperature, 500 mL of water was added for quenching, 1000 mL of ethyl acetate was added for extraction for 3 times, the organic phase was concentrated to obtain (310.24 g, 813.94 mmol) intermediate I, the yield was 81.39%, and the purity was 99.2%.

[0029] S2: In a 1000 mL three-necked flask, 500 mL of 1,4-dioxane, (9.69 g, 131.14 mmol) lithium carbonate, (100 g, 262.36 mmol) intermediate 1 were added, the temperature was controlled at 20 ℃, stirring, the reaction was carried out for 2 h, 250 mL of water was added, 500 mL of ethyl acetate was added for extraction for 3 times, and the crude product was concentrated to obtain (91.87 g, 237.33 mmol) product, the yield was 90.46%, and the purity was 99.3%.

[0030]

[0031] Embodiment 2

[0032] S1: In a 2000 mL three-necked flask, 1000 mL of tetrahydrofuran, (258.50 g, 2.00 mol) N,N-diisopropylethylamine were added, N2 was protected, stirring, (404.14 g, 2.00 mol) perfluoroethanesulfonyl fluoride was added, the temperature was controlled at 60 ℃, (22.4 L, 1.00 mol) ammonia was introduced, the reaction was carried out for 4 h, it was cooled to room temperature, 500 mL of water was added for quenching, 1000 mL of ethyl acetate was added for extraction for 3 times, and the organic phase was concentrated to obtain (319.76 g, 838.91 mmol) intermediate I, the yield was 83.89%, and the purity was 99.5%.

[0033] S2: In a 1000 mL three-necked flask, add 500 mL 1,4-dioxane, (14.54 g, 196.78 mmol) lithium carbonate, (100.00 g, 262.36 mmol) Intermediate 1, control temperature 30 °C, stir, react for 1 h, add 250 mL water, extract 3 times with 500 mL ethyl acetate, concentrate to get crude product, then refine with dimethyl carbonate to get (92.05 g, 237.80 mmol) product, yield 90.64%, purity 99.2%.

[0034]

[0035] Example 3

[0036] S1 : In a 2000 mL three-necked flask, add 1000 mL tetrahydrofuran, (465.30 g, 3.60 mol) N,N-diisopropylethylamine, N2 protection, stir, add (484.98 g, 2.40 mol) perfluoroethanesulfonyl fluoride, control temperature 55 °C, pass (22.4 L, 1.00 mol) ammonia, react for 5 h, reduce to room temperature, add 500 mL water to quench, extract 3 times with 1000 mL ethyl acetate, concentrate the organic phase to get (326.14 g, 855.65 mmol) Intermediate I, yield 85.57%, purity 99.3%.

[0037] S2: In a 1000 mL three-necked flask, add 500 mL 1,4-dioxane, (12.56 g, 169.98 mmol) lithium carbonate, (100.00 g, 262.36 mmol) Intermediate 1, control temperature 25 °C, stir, react for 1.5 h, add 250 mL water, extract 3 times with 500 mL ethyl acetate, concentrate to get crude product, then refine with dimethyl carbonate to get (93.61 g, 241.83 mmol) product, yield 92.17%, purity 99.4%.

[0038]

[0039]

[0040] Example 4

[0041] S1 : In a 2000 mL three-necked flask, add 1000 mL tetrahydrofuran, (414.78 g, 3.60 mol) N,N-diisopropylmethylamine, N2 protection, stirring, add (484.98 g, 2.40 mol) perfluoroethanesulfonyl fluoride, control the temperature at 55 °C, pass (22.4 L, 1.00 mol) ammonia, react for 5 h, reduce to room temperature, add 500 mL water to quench, add 1000 mL ethyl acetate to extract 3 times, concentrate the organic phase to obtain (334.21 g, 876.82 mmol) intermediate I, the yield is 87.68%, the purity is 99.4%.

[0042] Step S2 is the same as Example 3.

[0043]

[0044] Example 5

[0045] S1 : In a 2000 mL three-necked flask, add 1000 mL tetrahydrofuran, (414.78 g, 3.60 mol) N,N-diisopropylmethylamine, N2 protection, stirring, add (484.98 g, 2.40 mol) perfluoroethanesulfonyl fluoride, control the temperature at 55 °C, pass (22.4 L, 1.00 mol) ammonia, react for 5 h, reduce to room temperature, add 500 mL water to quench, add 1000 mL ethyl acetate to extract 3 times, concentrate the organic phase to obtain (334.21 g, 876.82 mmol) intermediate I, the yield is 87.68%, the purity is 99.4%.

[0046] Step S2 is the same as Example 3.

[0047]

[0048] Example 6

[0049] S1 : In a 2000 mL three-necked flask, add 1000 mL tetrahydrofuran, (414.78 g, 3.60 mol) N,N-diisopropylmethylamine, N2 protection, stirring, add (484.98 g, 2.40 mol) perfluoroethanesulfonyl fluoride, control the temperature at 55 °C, pass (22.4 L, 1.00 mol) ammonia, react for 5 h, reduce to room temperature, add 500 mL water to quench, add 1000 mL ethyl acetate to extract 3 times, concentrate the organic phase to obtain (334.21 g, 876.82 mmol) intermediate I, the yield is 87.68%, the purity is 99.4%.

[0050] Step S2 is the same as Example 3.

[0051]

[0052] Example 7

[0053] S1 : In a 2000 mL three-necked flask, add 1000 mL tetrahydrofuran, (414.78 g, 3.6 mol) N,N-diisopropylmethylamine, N2 protection, stirring, add (319.36 g, 1.20 mol) 1,2-sulfonyl fluoride-perfluoroethane, control temperature 55 °C, pass (22.4 L, 1.00 mol) ammonia, react 5 h, drop to room temperature, add 500 mL water to quench, add 1000 mL ethyl acetate to extract 3 times, concentrate the organic phase to obtain (203.44, 836.69 mmol) intermediate I, yield 83.67%, purity 99.4%.

[0054] Step S2 is the same as Example 3.

[0055]

[0056] Example 8

[0057] S1 : In a 2000 mL three-necked flask, add 1000 mL tetrahydrofuran, (414.78 g, 3.6 mol) N,N-diisopropylmethylamine, N2 protection, stirring, add (319.36 g, 1.20 mol) 1,2-sulfonyl fluoride-perfluoroethane, control temperature 55 °C, pass (22.4 L, 1.00 mol) ammonia, react 5 h, drop to room temperature, add 500 mL water to quench, add 1000 mL ethyl acetate to extract 3 times, concentrate the organic phase to obtain (203.44, 836.69 mmol) intermediate I, yield 83.67%, purity 99.4%.

[0058] Step S2 is the same as Example 3.

[0059]

[0060] Comparative Example 1

[0061] S1 : In a 2000 mL three-necked flask, add 1000 mL tetrahydrofuran, (414.78 g, 3.6 mol) N,N-diisopropylmethylamine, N2 protection, stirring, add (319.36 g, 1.20 mol) 1,2-sulfonyl fluoride-perfluoroethane, control temperature 55 °C, pass (22.4 L, 1.00 mol) ammonia, react 5 h, drop to room temperature, add 500 mL water to quench, add 1000 mL ethyl acetate to extract 3 times, concentrate the organic phase to obtain (203.44, 836.69 mmol) intermediate I, yield 83.67%, purity 99.4%.

[0062] Step S2 is the same as Example 3.

[0063]

[0064] Comparative Example 2

[0065] S1: In a 2000 mL three-necked flask, 1000 mL of tetrahydrofuran, (212.80 g, 3.60 mol) trimethylamine, N2 protection, stirring, adding (484.98 g, 2.40 mol) perfluoroethane sulfuryl fluoride, controlling the temperature at 55°C, passing (22.4 L, 1.00 mol) ammonia, reacting for 5 h, reducing to room temperature, adding 500 mL of water to quench, adding 1000 mL of ethyl acetate to extract 3 times, concentrating the organic phase to obtain (249.17 g, 653.71 mmol) intermediate I, with a yield of 65.37% and a purity of 99.0%.

[0066] Step S2 is the same as Example 3.

[0067]

[0068] Application test:

[0069] Test 1: The fluorinated bis-sulfonylimino lithium compound obtained from Example 1, 7 and 8 of the present application was taken as an electrolyte, respectively, and mixed with LiPF6 at a molar ratio of 1:1, and the volume ratio of the solvent was EC / DEC / EMC = 1:1:1. The performance of the battery was detected, and was recorded as electrolyte 1, electrolyte 2 and electrolyte 3. The blank control group electrolyte was LiPF6, and the volume ratio of the solvent was EC / DEC / EMC = 1:1:1. The ceramic separator was used, and after the electrolyte was injected, the soft pack battery was assembled in the glove box, and was tested after standing for 8 hours. The battery was activated by charging and discharging at 1 / 10C from 2.0V to 6.0V and above at room temperature 25°C, and then the cycle was carried out at 80°C with 1C charging and discharging.

[0070] Table 1 cycle test results

[0071]

[0072] As can be seen from Table 1, the fluorinated bis-sulfonylimino lithium compound as an electrolyte mixed with LiPF6 added to the battery has a 80°C cycle capacity retention rate of 92.7%-98.2% for 100-300 times, while the single LiPF6 electrolyte added to the battery has a 80°C cycle capacity retention rate of 83.4%-92.5% for 100-300 times, indicating that the fluorinated bis-sulfonylimino lithium compound as an electrolyte significantly improves the thermal stability and high temperature resistance of the electrolyte, thereby improving the safety of the lithium battery at high temperature.

[0073] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for synthesizing a lithium fluorodisulfonylimide compound, characterized by, The method comprises the following steps: S1: substituting compound I with ammonia under alkaline conditions to obtain intermediate I; the compound I is a sulfonyl fluoride-perfluoroalkyl compound; S2: forming a salt reaction of intermediate I with lithium carbonate to obtain a fluorinated bis-sulfonylimino lithium compound; The sulfonyl fluoride-perfluoroalkyl compound is perfluoroethanesulfonyl fluoride or 1,2-sulfonyl fluoride-perfluoroethane or 1,3-sulfonyl fluoride-perfluoropropane; The alkaline condition in the substituting reaction in step S1 is provided by an organic base; the organic base is one of N,N-diisopropylethylamine, N,N-diisopropylmethylamine, dimethylisopropylamine and diethylisopropylamine; The reaction temperature in the substituting reaction in step S1 is 50-60 DEG C, and the reaction time is 4-6 h; The reaction temperature in the salt forming reaction in step S2 is 20-30 DEG C, and the reaction time is 1-2 h.

2. The method of claim 1, wherein the fluorodisulfonylimide lithium compound is synthesized by the reaction of a fluorosulfonyl chloride and a lithium salt in a solvent. In the substituting reaction in step S1, the molar ratio of nitrogen in ammonia to sulfur in compound I is 1:2-1:2.

6.

3. The method of claim 2, wherein the fluorodisulfonylimide lithium compound is synthesized by the reaction of the compound of formula (2) with the compound of formula (3) in the presence of a solvent. In the substituting reaction in step S1, the molar ratio of sulfur in compound I to the organic base is 1:1-1:

2.

4. The method of claim 1, wherein the fluorodisulfonylimide lithium compound is synthesized by the reaction of a fluorosulfonyl chloride and a lithium salt in a solvent. The substituting reaction in step S1 is carried out in a solvent, and the solvent is tetrahydrofuran.

5. The method of claim 1, wherein the fluorodisulfonylimide lithium compound is synthesized by the reaction of a fluorosulfonyl chloride and a lithium salt in the presence of a solvent. In the salt forming reaction in step S2, the molar ratio of lithium carbonate to compound I is 1:2-1.5:

2.

6. The method of claim 1, wherein the fluorodisulfonylimide lithium compound is synthesized by the reaction of a fluorosulfonyl chloride and a lithium salt in a solvent. The salt forming reaction in step S2 is carried out in a solvent, and the solvent is 1,4-dioxane.

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