A method for preparing an imide lithium salt

Abstract

The application discloses a preparation method of an imidolide lithium salt, comprising the following steps: (1) dissolving a lithium salt precursor in an organic solvent; adding Li3N and stirring the reaction at a certain temperature; wherein the lithium salt precursor contains a sulfonyl group; (2) removing the solvent in the reaction solution and drying to obtain the imidolide lithium salt. The method for directly preparing the imidolide lithium salt by using lithium nitride has the highest atomic economic efficiency, a simplified production process and lower cost, and can promote better commercial development of the imidolide lithium salt.

Description

Technical Field

[0001] This application relates to a method for preparing imide-based lithium salts, belonging to the field of lithium-ion battery electrolyte preparation. Background Technology

[0002] Since their commercialization in 1991, lithium-ion batteries have experienced tremendous growth and development in portable devices such as mobile phones and laptops, primarily due to their excellent portability. In recent years, their application areas have continued to expand as lithium-ion batteries have been successfully used in large-scale energy storage systems such as electric vehicles. As a crucial component of energy storage, lithium-ion batteries have become a key technology in many different fields. Due to their widespread use in multiple sectors, more stringent requirements have been placed on the quality of lithium-ion batteries, prompting the technological field to continuously improve their performance and safety.

[0003] The electrolyte in a lithium-ion battery plays a crucial role in ion transport, ensuring high voltage and specific energy, and directly impacting battery quality. Among numerous electrolyte materials, lithium imide-based salts stand out in the lithium-ion battery field due to their superior conductivity, chemical stability, and thermal stability. This material can significantly improve the performance of lithium-ion batteries, including enhanced cycle stability and charging capacity. Furthermore, its excellent thermal stability contributes to improved battery safety. In domestic and international research fields, lithium imide-based salts have become a focus of research attention due to their multiple advantages. This attention demonstrates their important position and broad application prospects in lithium-ion battery technology.

[0004] However, the traditional synthesis process of lithium imide salts involves cumbersome procedures, complex reaction equipment, stringent temperature requirements, and arduous post-processing, all of which result in substantial production costs. These issues significantly limit the commercial application of lithium imide salts. Therefore, there is an urgent need to develop a simple and efficient method for preparing lithium imide salts. Summary of the Invention

[0005] To address this challenge, this application provides a method for preparing imide-based lithium salts, directly using lithium nitride. This method simplifies the complex production process and reduces raw material loss, significantly lowering production costs. Compared to traditional methods, the new method avoids cumbersome production steps, improves production efficiency, and thus promotes the commercial application of imide-based lithium salts. This innovative preparation method provides strong support for cost reduction, increased production efficiency, and sustainable development, opening up new possibilities for the widespread application of imide-based lithium salts in various fields.

[0006] This application provides a method for preparing an imide-based lithium salt, comprising the following steps:

[0007] (1) A lithium salt precursor is dissolved in an organic solvent; Li3N is added and the mixture is stirred to react; wherein the lithium salt precursor contains a sulfonyl group;

[0008] (2) Remove the solvent from the reaction solution and dry to obtain imide lithium salt.

[0009] Optionally, the lithium salt precursor has the structures shown in Formula 1 and Formula 2:

[0010]

[0011] In Formula 1, R1 is selected from halogens or C1-C3 alkyl groups, and the hydrogens in the alkyl groups are all replaced by halogens.

[0012] In Formula 2, X is a halogen; R2 is selected from halogens or C1-C3 alkyl groups, wherein the hydrogen in the alkyl group is replaced by a halogen.

[0013] Optionally, the lithium salt precursor is selected from one of the following substances:

[0014]

[0015] Optionally, the molar ratio of the lithium salt precursor to the Li3N is 2:0.7 to 1.3.

[0016] Optionally, the organic solvent is selected from at least one of chloroform (TCM), dichloromethane (DCM), ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), sulfolane, 1,3-dioxolane (DOL), dimethyl ethylene glycol (DME), tetraethylene glycol dimethyl ether (TEGDME), 1,4-dioxane, and tetrahydrofuran (THF).

[0017] Optionally, in step (1), the temperature of the stirring reaction is -10℃ to 35℃.

[0018] Optionally, in step (1), the stirring reaction time is 25 to 45 minutes.

[0019] Optionally, in step (2), the solvent in the reaction solution is removed by vacuum distillation.

[0020] Optionally, in step (2), the drying includes vacuum drying at 50–100°C.

[0021] The beneficial effects that this application can produce include:

[0022] (1) The method of this application utilizes the direct reaction of Li3N with lithium salt precursor in an organic solvent to obtain imide-based lithium salt in one step.

[0023] (2) Traditional preparation processes for imide-based lithium salts are complex and costly. The preparation process for imide-based lithium salts in this application is simple, efficient and low-cost. Attached Figure Description

[0024] Figure 1 This is the nuclear magnetic resonance spectrum of F element in lithium bis(trifluoromethanesulfonylimide) from Example 1. Detailed Implementation

[0025] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0026] In the description of this invention, the use of terms such as "first," "second," etc., is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0027] In the description of this invention, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0028] This application provides a method for preparing an imide-based lithium salt, comprising the following steps:

[0029] (1) A lithium salt precursor is dissolved in an organic solvent; Li3N is added and the mixture is stirred to react; wherein the lithium salt precursor contains a sulfonyl group;

[0030] (2) Remove the solvent from the reaction solution and dry to obtain imide lithium salt.

[0031] In some embodiments, the lithium salt precursor has the structures shown in Formula 1 and Formula 2:

[0032]

[0033] In Formula 1, R1 is selected from halogens or C1-C3 alkyl groups, and the hydrogens in the alkyl groups are all replaced by halogens.

[0034] In Formula 2, X is a halogen; R2 is selected from halogens or C1-C3 alkyl groups, wherein the hydrogen in the alkyl group is replaced by a halogen.

[0035] In this application, the halogen is selected from F, Cl, Br or I.

[0036] In some embodiments, the hydrogen in the alkyl groups of R1 and R2 is replaced by F.

[0037] In some embodiments, R1 is selected from F, perfluoromethyl, perfluoroethyl, or perfluoropropyl.

[0038] In some embodiments, R2 is selected from F, perfluoromethyl, perfluoroethyl, or perfluoropropyl.

[0039] In some embodiments, the lithium salt precursor is selected from one of the following substances:

[0040]

[0041] In some embodiments, according to the embodiments of this application, the reaction for generating the imide-based lithium salt is shown in Equation 3 below:

[0042]

[0043] R1 is selected from halogens or C1-C3 alkyl groups, wherein the hydrogen atoms in the alkyl group are all replaced by halogens.

[0044] In other embodiments, according to the embodiments of this application, the reaction for generating the imide-based lithium salt is shown in Equation 4 below:

[0045]

[0046] Wherein, X is a halogen; R2 is selected from halogens or C1-C3 alkyl groups, wherein the hydrogen in the alkyl group is replaced by a halogen.

[0047] In some embodiments, according to the present invention, no byproducts are generated in the reaction of Formula 3 above, and the atom utilization rate reaches 100%.

[0048] In some embodiments, according to the present invention, the byproducts of the reaction of Formula 4 above include LiX, such as LiF, LiCl, LiBr, LiI, lithium sulfonate, or lithium trifluoromethanesulfonate.

[0049] In some embodiments, the molar ratio of the lithium salt precursor to the Li3N is 2:0.7 to 1.3.

[0050] In some embodiments, the molar ratio of the lithium salt precursor to the Li3N is selected from a range of 2:0.7, 2:0.8, 2:0.9, 2:1, 2:1.1, 2:1.2, 2:1.3 or any two values.

[0051] The inventors discovered that a higher yield can be obtained when the molar ratio of the two is within this range. As the amount of Li3N decreases, the product yield decreases; increasing the amount of Li3N does not significantly improve the product yield.

[0052] In some embodiments, the organic solvent is selected from at least one of chloroform (TCM), dichloromethane (DCM), ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), sulfolane, 1,3-dioxolane (DOL), dimethyl ethylene glycol (DME), dimethyl tetraethylene glycol (TEGDME), 1,4-dioxane, and tetrahydrofuran (THF).

[0053] In some embodiments, in step (1), the temperature of the stirring reaction is -10°C to 35°C.

[0054] In some embodiments, in step (1), the temperature of the stirring reaction can be -10℃~-5℃, -5℃~0℃, 0℃~5℃, 5℃~10℃, 10℃~15℃, 15℃~20℃, 20℃~25℃, 25℃~30℃ or 30℃~35℃.

[0055] In some preferred embodiments, in step (1), the temperature of the stirring reaction is -10°C to 15°C; the inventors have found that within this range, the product yield can reach more than 90%.

[0056] In some embodiments, the stirring reaction in step (1) lasts for 25 to 45 minutes. The inventors have found that within this time range, the reaction is fully completed, and further extending the reaction time does not significantly improve the product yield.

[0057] In some embodiments, in step (1), the stirring reaction time can be 25 min, 30 min, 35 min, 40 min, 45 min or any range of two values.

[0058] In some embodiments, in step (2), the solvent in the reaction solution is removed by vacuum distillation.

[0059] In some embodiments, step (2) includes drying under reduced pressure at 50–100°C.

[0060] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0061] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0062] The yield calculation in the embodiments of this application is as follows:

[0063] Yield = Actual yield of target product / Theoretical yield of target product × 100%

[0064] Example 1

[0065] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0066] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at -5 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was then removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0067] The reaction mechanism in this embodiment is shown in Equation 5:

[0068]

[0069] The nuclear magnetic resonance F-spectrum of the product in this embodiment is as follows: Figure 1 As shown in the figure, a peak appears at a chemical shift of -79.1, which coincides with the peak position of lithium bis(trifluoromethanesulfonylimide), thus confirming the successful synthesis of lithium bis(trifluoromethanesulfonylimide).

[0070] The product yield of this embodiment was calculated to be 95.8%.

[0071] Example 2

[0072] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0073] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.07 mol of Li3N was added, and the mixture was stirred at -5 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was then removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0074] The reaction mechanism of this embodiment is shown in Equation 5.

[0075] The product yield of this embodiment was calculated to be 91.1%.

[0076] Example 3

[0077] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0078] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.08 mol of Li3N was added, and the mixture was stirred at -5 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0079] The reaction mechanism of this embodiment is shown in Equation 5.

[0080] The product yield of this embodiment was calculated to be 93.2%.

[0081] Example 4

[0082] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0083] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.09 mol of Li3N was added, and the mixture was stirred at -5 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was then dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0084] The reaction mechanism of this embodiment is shown in Equation 5.

[0085] The product yield of this embodiment was calculated to be 94.9%.

[0086] Example 5

[0087] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0088] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.11 mol of Li3N was added, and the mixture was stirred at -5 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0089] The reaction mechanism of this embodiment is shown in Equation 5.

[0090] The product yield of this embodiment was calculated to be 94.6%.

[0091] Example 6

[0092] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0093] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.12 mol of Li3N was added, and the mixture was stirred at -5 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was then dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0094] The reaction mechanism of this embodiment is shown in Equation 5.

[0095] The product yield of this embodiment was calculated to be 94.5%.

[0096] Example 7

[0097] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0098] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at 0 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was then removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0099] The reaction mechanism of this embodiment is shown in Equation 5.

[0100] The product yield of this embodiment was calculated to be 95.3%.

[0101] Example 8

[0102] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0103] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at 5 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was then dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0104] The reaction mechanism of this embodiment is shown in Equation 5.

[0105] The product yield of this embodiment was calculated to be 93.6%.

[0106] Example 9

[0107] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0108] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at 10 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was then dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0109] The reaction mechanism of this embodiment is shown in Equation 5.

[0110] The product yield of this embodiment was calculated to be 92.9%.

[0111] Example 10

[0112] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0113] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at 20 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was then removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0114] The reaction mechanism of this embodiment is shown in Equation 5.

[0115] The product yield of this embodiment was calculated to be 89.9%.

[0116] Example 11

[0117] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0118] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at -5 °C for 25 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was then dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0119] The reaction mechanism of this embodiment is shown in Equation 5.

[0120] The product yield of this embodiment is calculated to be 95.4%.

[0121] Example 12

[0122] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0123] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at -5 °C for 35 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0124] The reaction mechanism of this embodiment is shown in Equation 5.

[0125] The product yield of this embodiment was calculated to be 95.8%.

[0126] Example 13

[0127] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0128] 0.2 mol of trifluoromethanesulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at -5 °C for 40 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide and crude lithium trifluoromethanesulfonate. The solvent in the reaction solution was then removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bis(trifluoromethanesulfonyl)imide and lithium trifluoromethanesulfonate. The lithium bis(trifluoromethanesulfonyl)imide was then dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain lithium trifluoromethanesulfonate. Finally, the solvent in the filtrate was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0129] The reaction mechanism of this embodiment is shown in Equation 5.

[0130] The product yield of this embodiment was calculated to be 95.8%.

[0131] Example 14

[0132] This embodiment provides a method for directly preparing lithium bis(fluorosulfonyl)imide using lithium nitride, the steps of which are as follows:

[0133] 0.2 mol of fluorosulfonic anhydride solution was dissolved in 100 mL of DCM. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at -5 °C for 30 min to obtain crude lithium bisfluorosulfonylimide and crude lithium fluorosulfonate. The solvent in the reaction solution was removed by vacuum distillation, and the mixture was vacuum dried at 60 °C for 3 h to obtain a white crystalline mixture of lithium bisfluorosulfonylimide and lithium fluorosulfonate. The lithium bisfluorosulfonylimide was then dissolved in phenol solution (PhOH), filtered, and the white solid was vacuum dried for 3 h to obtain the lithium fluorosulfonate product. Finally, the solvent in the filtrate was removed by vacuum distillation, and the filtrate was vacuum dried at 60 °C for 3 h to obtain the white crystalline lithium bisfluorosulfonylimide product.

[0134] The reaction mechanism in this embodiment is shown in Equation 6:

[0135]

[0136] The product yield of this embodiment was calculated to be 95.1%.

[0137] Example 15

[0138] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0139] 0.2 mol of trifluoromethanesulfonyl chloride was dissolved in 100 mL of THF. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at -5 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide. The solvent in the reaction solution was then removed by vacuum distillation, and the product was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0140] The reaction mechanism of this embodiment is shown in Equation 7 below:

[0141]

[0142] The product yield of this embodiment was calculated to be 94.8%.

[0143] Example 16

[0144] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0145] 0.2 mol of trifluoromethanesulfonyl chloride was dissolved in 100 mL of EC. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at -5 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide. The solvent in the reaction solution was then removed by vacuum distillation, and the product was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0146] The reaction mechanism of this embodiment is shown in Equation 8:

[0147]

[0148] The product yield of this embodiment was calculated to be 92.1%.

[0149] Example 17

[0150] This embodiment provides a method for directly preparing lithium bis(trifluoromethanesulfonylimide) using lithium nitride, the steps of which are as follows:

[0151] 0.2 mol of trifluoromethanesulfonyl chloride was dissolved in 100 mL of DEC. After ultrasonic dispersion for 5 min, 0.1 mol of Li3N was added, and the mixture was stirred at -5 °C for 30 min to obtain crude lithium bis(trifluoromethanesulfonyl)imide. The solvent in the reaction solution was then removed by vacuum distillation, and the product was vacuum dried at 60 °C for 3 h to obtain white crystalline lithium bis(trifluoromethanesulfonyl)imide.

[0152] The reaction mechanism of this embodiment is shown in Equation 9:

[0153]

[0154] The product yield of this embodiment was calculated to be 91.1%.

[0155] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for producing an imidilithium salt, characterized by, Includes the following steps: (1) The lithium salt precursor is dissolved in an organic solvent; Li3N is added, and the mixture is stirred at a temperature of -10℃ to 35℃ for 25 to 45 minutes; wherein the lithium salt precursor contains a sulfonyl group; (2) Remove the solvent from the reaction solution and dry to obtain imide lithium salt.

2. The method of claim 1, wherein, The lithium salt precursor has the structure shown in Formula 1 or Formula 2: Formula 1 Formula 2 In Formula 1, R1 is selected from halogens or C1-C3 alkyl groups, and the hydrogens in the alkyl groups are all replaced by halogens. In Formula 2, X is a halogen; R2 is selected from halogens or C1-C3 alkyl groups, wherein the hydrogen in the alkyl group is replaced by a halogen.

3. The method of claim 1, wherein, The lithium salt precursor is selected from one of the following substances: 。 4. The method of claim 1, wherein, The molar ratio of the lithium salt precursor to the Li3N is 2:0.7~1.

3.

5. The method of claim 1, wherein, The organic solvent is selected from at least one of chloroform (TCM), dichloromethane (DCM), ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), sulfolane, 1,3-dioxolane (DOL), dimethyl ethylene glycol (DME), dimethyl tetraethylene glycol (TEGDME), 1,4-dioxane, and tetrahydrofuran (THF).

6. The method of claim 1, wherein, In step (2), the solvent in the reaction solution is removed by vacuum distillation.

7. The method of claim 1, wherein, In step (2), the drying includes vacuum drying at 50 to 100°C.

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