A method for preparing lithium bis(fluorosulfonyl)imide

Abstract

The present application relates to a method for preparing lithium bis(fluorosulfonyl)imide. A method for preparing lithium bis(fluorosulfonyl)imide includes: reacting an ammonia source, R·(HF) n and SO2F x Cl y in an organic solvent until the reaction is complete, and then subjecting the reaction solution to vacuum distillation to obtain an intermediate - bis(fluorosulfonyl)imide salt; wherein, 0 < n ≤ 3, x + y = 2, y ≠ 0, n - y ≥ 0, and R is an organic base; reacting the bis(fluorosulfonyl)imide salt with a lithium source in a solvent, and purifying after the reaction is complete to obtain lithium bis(fluorosulfonyl)imide. The present application improves production efficiency and product yield.

Description

Technical Field

[0001] The present application relates to the field of chemical industry, and in particular to a method for preparing lithium bis(fluorosulfonyl)imide. Background Art

[0002] Lithium bis(fluorosulfonyl)imide has the characteristics of good electrochemical stability, good hydrolysis resistance and high conductivity. It can be widely used in electrolytes, especially in power batteries, and can improve the cycle performance and rate performance of power batteries.

[0003] At present, there are extensive reports on the preparation process of lithium bis(fluorosulfonyl)imide, but the existing preparation processes all have shortcomings. For example, Chinese patent application CN111620315A discloses the following preparation method: the first step is to slowly introduce an organic base while continuously introducing the remaining amount of sulfuryl fluoride until the reaction is completed, and the reaction solution is directly subjected to reduced pressure distillation to obtain an intermediate bis(fluorosulfonyl)imide salt; the second step is to add lithium oxide powder to the above intermediate bis(fluorosulfonyl)imide salt in the presence of an organic solvent, filter, concentrate, add a non-aqueous poor solvent for crystallization, and obtain lithium bis(fluorosulfonyl)imide. The above process has problems such as long reaction time and low product yield.

[0004] To this end, the present invention is proposed. Summary of the invention

[0005] The main purpose of the present invention is to provide a method for preparing lithium bis(fluorosulfonyl)imide, which improves production efficiency and product yield.

[0006] In order to achieve the above objectives, the present invention provides the following technical solutions.

[0007] A method for preparing lithium bis(fluorosulfonyl)imide, comprising:

[0008] Make ammonia source, R·(HF) n and SO 2 F x Cl y The reaction is carried out in an organic solvent until completion, and then the reaction solution is distilled under reduced pressure to obtain an intermediate - bis(fluorosulfonyl)imide salt; wherein 0<n≤3, x+y=2, y≠0, ny≥0, and R is an organic base;

[0009] The bisfluorosulfonyl imide salt is reacted with a lithium source in a solvent, and after the reaction is completed, the bisfluorosulfonyl imide lithium is purified to obtain.

[0010] The above preparation method of the present invention uses four reactants to obtain the product through two-step reactions.

[0011] Compared with the prior art, the preparation method of the present invention has the following advantages:

[0012] On the one hand, by changing the types of sulfonyl and fluoride salt, the reaction time can be shortened, and the reaction for preparing the intermediate can be completed within 2 to 7 hours, which greatly improves the production efficiency and obtains a higher yield;

[0013] On the other hand, there is no need to pre-join some SO 2 F x Cl y , which simplifies the reaction process and further improves production efficiency.

[0014] In the present invention, n can take any value between 0 and 3 except 0, not limited to positive integers, such as 0.5, 1, 1.5, 2, 2.5, 3, etc. Possible values ​​of x include but are not limited to 0, 0.5, 1, 1.5, 2, etc. Possible values ​​of y include but are not limited to 0, 0.5, 1, 1.5, 2, etc.

[0015] In some embodiments, the ammonia source includes at least one of ammonia gas, ammonium fluoride, sulfonamide, aminosulfonic acid, and difluoroamine;

[0016] and / or,

[0017] R is selected from at least one of pyridine, picoline, N-methylpyrrolidone, imidazole, trimethylamine, triethylamine, tri-n-propylamine, and tri-n-butylamine;

[0018] and / or,

[0019] The organic solvent is one or more solvent combinations of acetonitrile, propionitrile, isopropionitrile, ethyl ether, propyl ether, isopropyl ether, tetrahydrofuran, acetone, butanone, methyl isobutyl ketone, and methyl pyrrolidone;

[0020] and / or,

[0021] The lithium source includes at least one of lithium hydroxide, lithium carbonate, lithium nitride and lithium oxide.

[0022] In some embodiments, the ammonia source can be any one of ammonia gas, ammonium fluoride, sulfonamide, aminosulfonic acid, and difluoroamine.

[0023] In some embodiments, the ammonia source can be a mixture of ammonia gas and ammonium fluoride, or a mixture of ammonium fluoride and sulfonamide, or a mixture of aminosulfonic acid and ammonium difluoride, or a mixture of ammonium fluoride and aminosulfonic acid.

[0024] In some embodiments, R is selected from at least one of trimethylamine, triethylamine, tri-n-propylamine, and tri-n-butylamine, and n=3.

[0025] These amines have high alkalinity and can participate in the reaction to fully absorb acid ions and chloride ions in the reaction solution, thereby promoting the forward progress of the reaction.

[0026] In some embodiments, x=0 or 1. 2 FCl and SO 2 Cl 2 The raw materials are readily available and the reaction yield is high.

[0027] In some embodiments, the ammonia source: R·(HF) n :SO 2 F x Cl y The molar ratio is 1:(1~5):(2~4). When R·(HF) n and SO 2 F x Cl y When the amount is appropriately excessive, it is beneficial to maintain the forward reaction rate significantly greater than the reverse reaction rate, thereby increasing the product yield.

[0028] Taking into account comprehensive factors such as yield and cost, in some embodiments, the ammonia source: R·(HF) n :SO 2 F x Cl y The molar ratio of is preferably 1:(2.5-5):(2.0-2.1).

[0029] In some embodiments, the reaction for preparing the bisfluorosulfonyl imide salt is carried out at -10 to 50° C., preferably at 20 to 35° C. The reaction rate can be increased at a higher temperature, and the product yield is high at a low temperature.

[0030] In some embodiments, the reaction time for preparing the bis(fluorosulfonyl)imide salt is within 2 to 7 hours, which is much shorter than the prior art.

[0031] In some embodiments, an organic base is further added in the reaction for preparing the bisfluorosulfonyl imide salt.

[0032] The addition of organic base can fully absorb acid ions and chloride ions in the reaction solution, thereby promoting the reaction to proceed in the positive direction.

[0033] In some embodiments, the purification method is: adding a poor solvent for crystallization, and the poor solvent is preferably one or more combinations of C5-C8 alkanes, benzene, toluene, xylene, dichloromethane, dichloroethane, trichloroethane, tetrachloroethane, and carbon tetrachloride.

[0034] These poor solvents can promote the crystallization of products quickly, and the crystals are of high quality.

[0035] In some embodiments, the crystal washing is further included after the crystallization. The crystallization further removes impurities, and the solvent of the crystallization is preferably the same as the poor solvent, and the miscible solvent is second.

[0036] In some embodiments, before the crystallization, the process further includes: desolventizing, filtering, and concentrating the reaction product of the bisfluorosulfonyl imide salt and the lithium source.

[0037] On the one hand, desolvation may recover usable solvents, and on the other hand, it can improve product purity. Removal methods include but are not limited to high temperature evaporation, low pressure, adsorption, etc.

[0038] In some embodiments, the conditions for the reduced pressure distillation are: material temperature 50-55°C, vacuum ≥-0.09Mpa.

[0039] In some embodiments, after the reduced pressure distillation, the method further comprises: washing with water to obtain a bis(fluorosulfonyl)imide salt. The present invention finds that washing with water not only improves the purity of the product, but also does not cause the final bis(fluorosulfonyl)imide lithium to have an excessively high water content.

[0040] In summary, compared with the prior art, the present invention has at least achieved the following technical effects:

[0041] The reaction time in the preparation of lithium bis(fluorosulfonyl)imide is shortened to improve the product yield; at the same time, the purification steps and operating conditions are further optimized to improve the product purity.

[0042] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0044] Figure 1 is a schematic diagram of a secondary battery according to an embodiment of the present application;

[0045] Figure 2 yes Figure 1 An exploded view of a secondary battery according to an embodiment of the present application is shown;

[0046] Figure 3 is a schematic diagram of a battery module according to an embodiment of the present application;

[0047] Figure 4 is a schematic diagram of a battery pack according to an embodiment of the present application;

[0048] Figure 5 yes Figure 4An exploded view of a battery pack according to an embodiment of the present application is shown;

[0049] Figure 6 FIG. 1 is a schematic diagram of an electric device using a secondary battery according to an embodiment of the present application as a power source.

[0050] Description of reference numerals:

[0051] 1 battery pack; 2 upper box; 3 lower box; 4 battery module; 5 secondary battery; 51 shell; 52 electrode assembly; 53 top cover assembly. DETAILED DESCRIPTION

[0052] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0054] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0055] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0056] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0057] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0058] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0059] The present invention is based on the following two-step reaction to obtain lithium bis(fluorosulfonyl)imide:

[0060] The first step, ammonia source + R·(HF)n + SO2FxCly → bis(fluorosulfonyl)imide salt + (hydrofluoride or hydrochloride);

[0061] The second step: bis(fluorosulfonyl)imide salt + lithium source → lithium bis(fluorosulfonyl)imide + R.

[0062] The lithium bis(fluorosulfonyl)imide prepared by the process of the present invention can be used in battery electrolyte, but this does not limit the application scope of the present invention. The following only takes lithium ion secondary battery as an example to introduce the application scope of lithium bis(fluorosulfonyl)imide.

[0063] In one embodiment of the present application, a secondary battery is provided.

[0064] Generally, a secondary battery includes a positive electrode sheet, a negative electrode sheet, an electrolyte and a separator. During the battery charging and discharging process, active ions are embedded and released back and forth between the positive electrode sheet and the negative electrode sheet. The electrolyte plays the role of conducting ions between the positive electrode sheet and the negative electrode sheet. The separator is set between the positive electrode sheet and the negative electrode sheet, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.

[0065] [Positive electrode]

[0066] The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, wherein the positive electrode film layer includes the positive electrode active material of the first aspect of the present application.

[0067] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0068] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0069] In some embodiments, when the secondary battery is a lithium-ion battery, the positive electrode active material may adopt a positive electrode active material for lithium-ion batteries known in the art. As an example, the positive electrode active material may include at least one of the following materials: a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 、LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi1 / 3Co1 / 3Mn1 / 3O2 (also referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (also referred to as NCM523), LiNi 0.5 Co=Mn 0.25 O 2 (also referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2) and its modified compounds, etc. Examples of lithium phosphates containing olivine structures may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), at least one of a composite material of lithium manganese phosphate and carbon, a composite material of lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0070] In some embodiments, when the secondary battery is a sodium ion battery, the positive electrode active material may be a positive electrode active material for a sodium ion battery known in the art. As an example, the positive electrode active material may be used alone or in combination of two or more. The positive electrode active material may be selected from sodium iron composite oxide (NaFeO 2 ), sodium cobalt composite oxide (NaCoO 2 ), sodium chromium composite oxide (NaCrO 2 ), sodium manganese composite oxide (NaMnO 2 ), sodium nickel composite oxide (NaNiO 2 ), sodium nickel titanium composite oxide (NaNi 1 / 2 Ti 1 / 2 O 2 ), sodium nickel manganese composite oxide (NaNi 1 / 2 Mn 1 / 2 O 2 ), sodium iron manganese composite oxide (Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O 2 ), sodium nickel cobalt manganese composite oxide (NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 ), sodium iron phosphate (NaFePO 4 ), sodium manganese phosphate (NaMnPO 4 ), sodium cobalt phosphate (NaCoPO 4 ), Prussian blue materials, polyanion materials (phosphates, fluorophosphates, pyrophosphates, sulfates), etc., but the present application is not limited to these materials. The present application can also use other traditionally known materials that can be used as positive electrode active materials for sodium ion batteries.

[0071] In some embodiments, the positive electrode film layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0072] In some embodiments, the positive electrode film layer may further include a conductive agent, which may include, for example, at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0073] In some embodiments, the positive electrode sheet can be prepared in the following manner: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.

[0074] [Negative electrode]

[0075] The negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.

[0076] As an example, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0077] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0078] In some embodiments, the negative electrode active material may adopt the negative electrode active material for the battery known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0079] In some embodiments, the negative electrode film layer may further include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).

[0080] In some embodiments, the negative electrode film layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0081] In some embodiments, the negative electrode film layer may optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0082] In some embodiments, the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.

[0083] [Electrolytes]

[0084] The electrolyte conducts ions between the positive electrode and the negative electrode.

[0085] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent. The process of the present invention can be used to prepare lithium bis(fluorosulfonyl)imide as an electrolyte.

[0086] In some embodiments, the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0087] [Isolation film]

[0088] In some embodiments, the secondary battery further includes a separator. The present application has no particular limitation on the type of separator, and any known porous separator with good chemical stability and mechanical stability can be selected.

[0089] In some embodiments, the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0090] In some embodiments, the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.

[0091] In some embodiments, the secondary battery may include an outer package, which may be used to encapsulate the electrode assembly and the electrolyte.

[0092] In some embodiments, the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the secondary battery may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0093] The present application has no particular limitation on the shape of the secondary battery, which may be cylindrical, square or any other shape. Figure 1 The secondary battery 5 is a square structure as an example.

[0094] In some embodiments, reference Figure 2 , the outer packaging may include a shell 51 and a cover plate 53. Among them, the shell 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 51 has an opening connected to the receiving cavity, and the cover plate 53 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation membrane can form an electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.

[0095] In some embodiments, secondary batteries may be assembled into a battery module. The number of secondary batteries contained in the battery module may be one or more, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery module.

[0096] Figure 3 4 is an example of a battery module. Figure 3 In the battery module 4, the plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4. Of course, they may also be arranged in any other manner. Further, the plurality of secondary batteries 5 may be fixed by fasteners.

[0097] Optionally, the battery module 4 may further include a housing having a receiving space, and the plurality of secondary batteries 5 are received in the receiving space.

[0098] In some embodiments, the battery modules described above may also be assembled into a battery pack. The battery pack may contain one or more battery modules, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.

[0099] Figure 4 and Figure 5 1 is a battery pack 1 as an example. Figure 4 and Figure 5 The battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery modules 4. The plurality of battery modules 4 can be arranged in the battery box in any manner.

[0100] In addition, the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application. The secondary battery, battery module, or battery pack can be used as a power source for the electrical device, and can also be used as an energy storage unit for the electrical device. The electrical device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto.

[0101] As the electrical device, a secondary battery, a battery module or a battery pack may be selected according to its usage requirements.

[0102] Figure 6 The power consumption device is taken as an example. The power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the high power and high energy density requirements of the power consumption device for the secondary battery, a battery pack or a battery module can be used.

[0103] Another example of a device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be thin and light, and a secondary battery may be used as a power source.

[0104] Based on the reaction principle of lithium bis(fluorosulfonyl)imide described above, the present invention provides the following embodiments, and the types of reactants or reaction conditions of each embodiment are different.

[0105] Example 1

[0106] 1) Reaction for preparing intermediates

[0107] Add 404g triethylamine (4mol), 161g triethylamine trihydrofluoride (1.0mol), 300g acetonitrile and 283g sulfuryl chloride (2.1mol) into the reactor, start stirring and cool to -5~5°C, slowly introduce 17g ammonia (1mol), after the addition of ammonia is completed, keep warm for 5h, discharge the reaction liquid and filter.

[0108] 2) Purification of intermediates

[0109] The reaction solution of step 1) is subjected to high vacuum distillation under the conditions of material temperature of 50-55°C and vacuum ≥-0.09Mpa, and acetonitrile and part of the unreacted triethylamine are recovered to obtain a bis(fluorosulfonyl)imide triethylamine salt concentrate. Impurities such as chloride ions, fluoride ions, and triethylamine hydrochloride in the concentrate are washed and removed with deionized water to obtain a pure bis(fluorosulfonyl)imide triethylamine salt.

[0110] 3) Preparation and purification of lithium bis(fluorosulfonyl)imide

[0111] 16.5 g of lithium oxide (0.55 mol) was added to the above-mentioned bis(fluorosulfonyl)imide triethylamine salt, and the mixture was stirred at room temperature for 3 h. After the filtrate was desolventized, concentrated and filtered, 200 g of dichloromethane was added for crystallization and filtration. The crystals were then cleaned with 100 g of dichloromethane and dried in vacuo to obtain 168.5 g of lithium bis(fluorosulfonyl)imide (0.9 mol). The yield was 90.1% (calculated based on ammonia source), the purity was 97.8%, and the impurity Cl - The content is 1.8ppm, and the impurity HF content is 33.7ppm.

[0112] Example 2

[0113] The difference from Example 1 is that no triethylamine is added, and the amount of triethylamine trihydrofluoride is changed to 5 mol. The remaining steps and operating conditions are the same as those in Example 1.

[0114] Embodiment 3-5

[0115] The difference from Example 2 is that the hydrofluoride of the organic base used in step 1) is different, and triethylamine trihydrofluoride is replaced by pyridine monohydrofluoride, imidazole dihydrofluoride, and sodium hydroxide, respectively, and the amount used is about 5.0 mol, as shown in the table below.

[0116] Example Hydrofluoride of organic base Example 2 Triethylamine trihydrofluoride Example 3 Pyridine monohydrofluoride Example 4 Imidazole dihydrofluoride Example 5 Sodium hydroxide

[0117] Embodiment 6-8

[0118] The difference from Example 2 is that the ammonia source used in step 1) is different. Ammonia gas is replaced by ammonium fluoride, sulfonamide, and aminosulfonic acid, respectively, and the amount used is about 1.0 mol. The remaining steps and operating conditions are the same as those in Example 2, as shown in the table below.

[0119] Example Ammonia source Example 2 Ammonia Example 6 Ammonium fluoride Example 7 Sulfonamide Example 8 Sulfamic acid

[0120] Example 9

[0121] The difference from Example 2 is that sulfuryl chloride is replaced by sulfuryl fluoride SO 2 FCl, dosage is 2.1 mol.

[0122] Example 10

[0123] The difference from Example 9 is that triethylamine trihydrofluoride is replaced by pyridine monohydrofluoride.

[0124] Examples 11-14

[0125] The difference from Example 2 is that the organic solvent and amount used in step 1) are changed, acetonitrile is replaced by ether, tetrahydrofuran, acetone, and methyl pyrrolidone, respectively, and the remaining steps and operating conditions are the same as those in Example 2.

[0126] Example Organic solvents Dosage Example 2 Acetonitrile 300g Embodiment 11 Ether 555g Example 12 Tetrahydrofuran 540g Example 13 acetone 435g Embodiment 14 Methylpyrrolidone 742g

[0127] Examples 15-16

[0128] The difference from Example 2 is that the lithium source used in step 3) is changed, and lithium oxide is replaced by lithium hydroxide and lithium carbonate, respectively, and the amounts used are shown in the following table.

[0129] Example Lithium Source Dosage Example 2 Lithium Oxide 0.55mol Embodiment 15 Lithium hydroxide 1.1mol Example 16 Lithium carbonate 0.55mol

[0130] Examples 17-19

[0131] The difference from Example 2 is the different consumption of triethylamine trihydrofluoride, see the following table for details, and the remaining steps and operating conditions are all the same as in Example 2.

[0132] Example Amount of triethylamine trihydrofluoride / mol Example 2 5 Embodiment 17 1 Embodiment 18 3 Embodiment 19 6

[0133] Examples 20-22

[0134] The difference from Example 2 is that the amount of sulfuryl chloride used is different, see the table below for details, and the remaining steps and operating conditions are the same as those in Example 2.

[0135] Example Amount of sulfuryl chloride / mol Example 2 2.1 Embodiment 20 4 Embodiment 21 3 Embodiment 22 2

[0136] Examples 23-26

[0137] The difference from Example 2 is that the reaction temperature of step 1) is different, as shown in the table below, and the remaining steps and operating conditions are the same as those of Example 2.

[0138]

[0139]

[0140] Examples 27-30

[0141] The difference from Example 2 is that the reaction time of step 1) is different, as shown in the following table, and the remaining steps and operating conditions are the same as those of Example 2.

[0142] Example Reaction time of step 1) / h Example 2 5 Embodiment 27 2 Embodiment 28 4 Embodiment 29 7 Embodiment 30 8

[0143] Embodiment 31

[0144] The difference from Example 2 is that the conditions of the reduced pressure distillation in step 2) are different, as shown in the table below.

[0145] Example Step 1) vacuum distillation conditions Example 2 50~55℃, vacuum ≥-0.09mpa Embodiment 31 50~55℃, vacuum≤-0.05mpa

[0146] Comparative Example 1

[0147] The difference from Example 2 is that sulfuryl chloride is replaced by sulfuryl fluoride, and other conditions are the same as those in Example 2.

[0148] Comparative Example 2

[0149] Add 14.8g ammonium fluoride (0.4mol) and 300g acetonitrile to a 1000ml stainless steel reactor, seal the system, cool to 10°C, evacuate to 0.09MPa, and then introduce sulfuryl fluoride gas to 0.1MPa. Pass 161.6g (1.6mol) of triethylamine within 3h. At the same time, continue to introduce sulfuryl fluoride to 82g (0.8mol), which takes a total of 13h. The reaction solution is distilled under high vacuum and reduced pressure, and acetonitrile, triethylamine and triethylamine hydrofluoride are recovered to obtain bisfluorosulfonyl imide triethylamine. Add 56g acetonitrile and 12g lithium oxide (0.4mol) powder to the above-mentioned bisfluorosulfonyl imide triethylamine salt, and stir at room temperature for 9h. Filter, desolventize and concentrate the filtrate, add 130g dichloromethane to crystallize, filter, and vacuum dry to obtain white solid powder lithium bisfluorosulfonamide.

[0150] Comparison of the preparation results of all the above embodiments and comparative examples is shown in the following table.

[0151] Preparation results of examples and comparative examples

[0152]

[0153]

[0154]

[0155] The results in Table 1 show:

[0156] Adding triethylamine to absorb tail gas can improve product purity;

[0157] Compared with other salts, triethylamine trihydrofluoride has better comprehensive effects and can take into account both purity and yield;

[0158] When ammonium fluoride is used as the ammonia source, the yield and purity will be significantly reduced;

[0159] Sulfuryl fluoride is more suitable as a reaction raw material than sulfuryl chloride, and the yield and purity will be significantly improved;

[0160] The type of organic solvent has little effect on the reaction results;

[0161] The yield of lithium carbonate as a lithium salt will decrease significantly;

[0162] The amount of triethylamine trihydrofluoride used has a significant effect on the yield and purity, and is preferably 5 to 6 mol.

[0163] In summary, it can be seen that the type of raw materials involved in each chemical reaction has a significant impact on the yield and purity.

[0164] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A method for preparing lithium bis(fluorosulfonyl)imide, It is characterized in that include: Make ammonia source, R·(HF) n and SO 2 F x Cl y The reaction is carried out in an organic solvent at -10 to 50°C until completion, and then the reaction solution is subjected to reduced pressure distillation to obtain an intermediate, a bisfluorosulfonyl imide salt; wherein 0<n≤3, x+y=2, x≠0, y≠0, ny≥0, and R is an organic base; the organic solvent is one or more solvent combinations of acetonitrile, propionitrile, isopropionitrile, ethyl ether, propyl ether, isopropyl ether, tetrahydrofuran, acetone, butanone, methyl isobutyl ketone, and methyl pyrrolidone; the reaction time for preparing the bisfluorosulfonyl imide salt is 2 to 7 hours; The bisfluorosulfonyl imide salt is reacted with a lithium source in a solvent, and after the reaction is completed, the bisfluorosulfonyl imide lithium is purified to obtain.

2. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 1, It is characterized in that The ammonia source includes at least one of ammonia gas, ammonium fluoride, sulfonamide, and difluoroamine; and / or, R is selected from at least one of pyridine, picoline, N-methylpyrrolidone, imidazole, trimethylamine, triethylamine, tri-n-propylamine, and tri-n-butylamine; and / or, The lithium source includes at least one of lithium hydroxide, lithium carbonate, lithium nitride and lithium oxide.

3. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 2, It is characterized in that R is at least one selected from trimethylamine, triethylamine, tri-n-propylamine, and tri-n-butylamine, and n=3.

4. The method for preparing lithium bis(fluorosulfonyl)imide according to any one of claims 1 to 3, It is characterized in that x＝1。 5. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 1, It is characterized in that Ammonia source is measured in terms of nitrogen molar amount, ammonia source: R·(HF) n :SO 2 F x Cl y The molar ratio is 1:(1~5):(2~4).

6. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 5, It is characterized in that Ammonia source is measured in terms of nitrogen molar amount, ammonia source: R·(HF) n :SO 2 F x Cl y The molar ratio is 1:(2.5~5):(2.0~2.1).

7. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 1, It is characterized in that The reaction for preparing the bisfluorosulfonyl imide salt is carried out at 20 to 35°C.

8. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 1, It is characterized in that An organic base is also added in the reaction for preparing the bisfluorosulfonyl imide salt.

9. The method for preparing lithium bis(fluorosulfonyl)imide according to any one of claims 1 to 3 or any one of claims 5 to 8, It is characterized in that The purification method is: adding a poor solvent for crystallization.

10. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 9, It is characterized in that The poor solvent is one or more combinations of C5-C8 alkanes, benzene, toluene, xylene, dichloromethane, dichloroethane, trichloroethane, tetrachloroethane, and carbon tetrachloride.

11. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 9, It is characterized in that The crystallization step further includes crystal washing.

12. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 11, It is characterized in that Before the crystallization, the process also includes: desolventizing, filtering and concentrating the reaction product of the bisfluorosulfonyl imide salt and the lithium source.

13. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 1, It is characterized in that The conditions of the reduced pressure distillation are: material temperature 50-55°C, vacuum ≥-0.09Mpa.

14. The method for preparing lithium bis(fluorosulfonyl)imide according to claim 1 or 13, It is characterized in that After the reduced pressure distillation, the method further comprises: washing with water to obtain a bisfluorosulfonyl imide salt.

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