Cyclic sulfate compositions, methods of making and using same

Abstract

The present application relates to the technical field of battery, in particular to a cyclic sulfate composition, and its preparation method and application. The composition comprises a cyclic sulfate compound represented by formula (1), and further comprises a sulfate compound represented by formula (A) and / or a carbonate compound represented by formula (B) in the composition: (1) (A) (B). The present application obtains a composition containing a target product, and the composition contains by-products in addition to the target impurities. Advantageously, the by-products with specific structures serve as lithium ion battery electrolyte additives, and have almost the same improvement ability as the target product for the performance of lithium ion batteries. The method in the present application has simple process and mild conditions, and can greatly reduce the cost required for removing impurities.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a cyclic sulfate composition, its preparation method, and its application. Background Technology

[0002] In tetrahydrofuran-3,4-cyclic sulfates, the cyclic sulfates are strong alkylating agents, reactive to a variety of nucleophiles, and exhibit complementary regioselectivity. During nucleophilic reactions, the cyclic sulfates undergo ring-opening flipping to generate the corresponding sulfate ester, which can serve as an effective protecting group for the alcohol. Hydrolysis of the sulfate ester can be readily achieved using a catalytic amount of acid in a moist solvent (such as diethyl ether or dioxane) to generate an alcohol functional group, which can then undergo further iterative reactions, reported in solid-phase etherification reactions (see J. Comb. Chem. 2001, 3, 6-8).

[0003] Existing technologies (such as patent WO2005005398 and literature J. Med. Chem. 2008, 51, 6558–6562) have also reported the use of tetrahydrofuran-3,4-cyclic sulfate as an intermediate in the synthesis of oxazolidinone antibacterial drugs.

[0004] The main reported methods for synthesizing tetrahydrofuran-3,4-cyclic sulfate esters are as follows:

[0005] 1) The reaction was carried out under reflux in carbon tetrachloride solvent using 3,4-diol and thionyl chloride as raw materials, then cooled and diluted with acetonitrile, and then sodium periodate, ruthenium trichloride and water were added and reacted at room temperature to obtain the product;

[0006] References: J. Am. Chem. Soc. 1988, 110, 7538-7539; J. Comb. Chem. 2001, 3, 6-8; WO2005005398; J. Med. Chem. 2008, 51, 6558–6562. This reaction proceeds in two steps: first, sulfite is formed, then oxidized to sulfate. The yield is very low, and the oxidant sodium periodate and catalyst ruthenium chloride used in the second step are expensive, resulting in high costs. Most importantly, the reaction byproduct sulfite is difficult to separate, and the use of thionyl chloride as a raw material also makes removal difficult, leading to excessive chloride ions.

[0007] 2) It is obtained by reacting 2,5-dihydrofuran, iodobenzenesulfonylbenzene, and sulfur trioxide in DMF and dichloromethane solvent;

[0008] Reference: Tetrahedron Letters 44 (2003) 1655–1657. This method also suffers from low yield, high cost of the starting material iodobenzoylbenzene, and numerous byproducts that are difficult to purify.

[0009] The current methods for obtaining tetrahydrofuran-3,4-cyclic sulfates mainly focus on their use as intermediates in downstream applications, with little attention paid to the performance of the product itself, such as product purity, color, and the removal and retention of trace impurities.

[0010] Patent KR20220023159A mentions that tetrahydrofuran-3,4-cyclic sulfate, as a cyclic ether diol derivative, can be used as an additive in secondary battery electrolytes. Patent CN118825414A examines the effect of tetrahydrofuran-3,4-cyclic sulfate as a functional additive on battery performance in specific electrolyte formulations. CN118825414A also discloses a method for synthesizing tetrahydrofuran-3,4-cyclic sulfate, which involves mixing and reacting tetrahydrofuran-3,4-diol and N,N'-thiodiimidazole in acetonitrile solvent, followed by a series of separation operations to obtain the product.

[0011] A white powdery solid was obtained in CN118825414A, but the product quality was still not examined. In fact, in this process, the raw material tetrahydrofuran-3,4-diol and the byproduct pyrazole are mixed into the target product and are difficult to separate.

[0012] However, in the field of lithium-ion batteries, the identification and quantification of impurities in electrolytes or functional additives, and their impact on battery performance, are crucial. For example, impurities carrying unstable protons can lead to a decrease in the stability and even the overall performance of lithium-ion batteries due to their interference with electrochemical reactions. The application of lithium-ion batteries necessitates products with high purity (minimal impurities), which means that achieving the above methods requires significant costs to improve product purity. Residual impurities can poison the target product, hindering its application in lithium-ion battery electrolytes. Summary of the Invention

[0013] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a cyclic sulfate composition and a method for preparing the same. The preparation method provided by this invention can obtain the target product in high yield without requiring a complex impurity removal process. The obtained product can be directly used in lithium-ion battery electrolytes, which is beneficial for improving the overall performance of lithium-ion batteries.

[0014] The technical solution of this invention is:

[0015] A first aspect of the present invention provides a composition comprising a cyclic sulfate compound of formula (1), wherein the composition further comprises a sulfate compound of formula (A) and / or a carbonate compound of formula (B):

[0016]

[0017] A second aspect of the present invention provides a method for preparing a composition, the method comprising the following steps:

[0018] 1) Using erythritol and sulfonyl fluoride as raw materials, an acid-binding agent is added, and the reaction is carried out in an organic solvent;

[0019] 2) Quench the reaction with water, separate the organic phase, wash with water and dry to obtain the crude product;

[0020] 3) The crude product obtained in step 2) is concentrated, crystallized, and dried to obtain the composition.

[0021] A third aspect of the present invention provides the use of compositions as described in the present invention and / or compositions prepared by the preparation methods as described in the present invention in electrolytes.

[0022] A fourth aspect of the present invention provides an electrolyte comprising the composition as described in the present invention and / or a composition prepared by the preparation method as described in the present invention.

[0023] By adopting the aforementioned technical solution, the beneficial effects of the present invention are:

[0024] Compared to existing preparation processes, this invention yields a composition containing the target product, which also contains byproducts other than the target impurity. Advantageously, these byproducts, with their specific structures, serve as additives for lithium-ion battery electrolytes, exhibiting almost the same performance-enhancing capabilities as the target product. The method described in this application is simple, operates under mild conditions, and significantly reduces the cost required for impurity removal. Attached Figure Description

[0025] Figure 1 This is the chromatogram obtained from a blank injection;

[0026] Figure 2 The chromatogram of the compound sample shown in formula (A);

[0027] Figure 3 The chromatogram of the compound sample shown in formula (B);

[0028] Figure 4 The chromatogram of the sample obtained in Example 1;

[0029] Figure 5 The chromatogram of the sample obtained in Example 2;

[0030] Figure 6 The chromatogram of the sample obtained in Example 3;

[0031] Figure 7 The chromatogram of the sample obtained in Example 4;

[0032] Figure 8 The chromatogram of the sample obtained in Example 5;

[0033] Figure 9 The chart shows a comparison of the high-temperature storage performance of batteries obtained from the comparative application examples and application examples 1 to 7.

[0034] Figure 10 The diagram shows a comparison of the DC impedance of the batteries obtained from the comparative application examples and application examples 1 to 7.

[0035] Figure 11 The graph shows a comparison of the low-temperature discharge performance of the batteries obtained from the comparative application examples and application examples 1 to 7.

[0036] Figure 12 The chart shows a comparison of the battery rate charging performance obtained from the comparative application examples and application examples 1 to 7.

[0037] Figure 13 The graph shows a comparison of the rate discharge performance of the batteries obtained from the comparative application examples and application examples 1 to 7.

[0038] Figure 14 The graph shows a comparison of the high-temperature cycling performance of the batteries obtained from the comparative application examples and application examples 1 to 7. Detailed Implementation

[0039] The following describes in detail the embodiments of the cyclic sulfate composition, its preparation method, and its application provided by the present invention.

[0040] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0041] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0042] In this article, when referring to units of data ranges, if a unit is only followed by the right endpoint, it means that the units of the left and right endpoints are the same.

[0043] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0044] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0045] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0046] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0047] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0049] In the existing technology, the formation process of tetrahydrofuran-3,4-cyclic sulfate is affected by the reaction raw materials, solvents and catalysts, and impurities are easily mixed into the product. The presence of these impurities affects its application in electrolytes. Even trace amounts of these components can poison the electrolyte and lead to a decrease in battery performance.

[0050] Using the method of this invention, the cyclic sulfate compound of formula (1) can be obtained in high yield. Simultaneously, the sulfate compound of formula (A) and the carbonate compound of formula (B) are obtained as byproducts. However, when these two compounds are used as additives in the electrolyte, their improvement on the battery's high-temperature storage, DC resistance, low-temperature discharge, rate capability, and high-temperature cycling performance at different temperatures is comparable to that of the cyclic sulfate compound of formula (1). In other words, although the sulfate compound of formula (A) and the carbonate compound of formula (B) exist as impurities in the target product, it does not affect their application in the electrolyte. All three can be used as a composition in the electrolyte and battery. In the synthesis process described in this invention, no additional cost is required to remove impurities. Based on this, this application was completed.

[0051] Cyclic sulfate compositions

[0052] The present invention provides a composition comprising a cyclic sulfate compound of formula (1), wherein the composition further comprises a sulfate compound of formula (A) and / or a carbonate compound of formula (B):

[0053]

[0054] In the above composition, the total content of the sulfate ester compound of formula (A) and the carbonate compound of formula (B) in the composition is greater than 1 ppm and less than 10,000 ppm, or any value between them or a range between any two values, where ppm is a mass reference.

[0055] Furthermore, in the above composition, the total content of the sulfate compound of formula (A) and the carbonate compound of formula (B) in the composition is greater than 1 ppm and less than 5000 ppm, or any value between them or a range between any two values, where ppm is a mass basis. The content of the cyclic sulfate compound of formula (1) in the composition is 99% or more by mass.

[0056] Furthermore, by mass, the cyclic sulfate compound represented by formula (1) is present in the composition at a content of 99.5% or more.

[0057] Among them, the compound shown in formula (1) is a tetrahydrofuran-3,4-cyclic sulfate ester, which can be called tetrahydrofuran[3,4-d]-1,3,2-dioxothiacyclopentane-2,2-dioxide.

[0058] The compound shown in formula (A) is erythrose bicyclic sulfate, which can be called [4,4'-bis(1,3,2-dioxothionane)]2,2,2',2'-tetraoxide or dithiosulfate.

[0059] The compound shown in formula (B) is a tetrahydrofuran-3,4-cyclic carbonate, which can be called tetrahydrofluoro[3,4-d][1,3]dioxol-2-one.

[0060] [Preparation Method of Cyclic Sulfate Composition] The present invention also provides a method for preparing a composition, the preparation method comprising the following steps:

[0061] 1) Using erythritol and sulfonyl fluoride as raw materials, an acid-binding agent is added, and the reaction is carried out in an organic solvent;

[0062] 2) Quench the reaction with water, separate the organic phase, wash with water and dry to obtain the crude product;

[0063] 3) The crude product obtained in step 2) is concentrated, crystallized, and dried to obtain the composition.

[0064] The preparation method of the present invention is to prepare a standard product in one step using inexpensive and readily available erythritol as a raw material, and the other reactants and excipients used are also inexpensive and low cost.

[0065] In the preparation method of the composition provided by this invention, step 1) uses erythritol and sulfonyl fluoride as raw materials, adds an acid-binding agent, and reacts in an organic solvent. Specifically:

[0066] In step 1) of the present invention, the molar ratio of erythritol and acid-binding agent is 1:1.7~3 and any value between them or any range between two values, and can be selected as 1:1.7~2 or 1:2~3.

[0067] In step 1) of this invention, the acid-binding agent is selected from one or more of triethylamine, NaHCO3, tetramethylethylenediamine, and pyridine.

[0068] In step 1) of this invention, the mass-volume ratio of erythritol to organic solvent is 1:4 to 8 and any value between them or any range between two values, and can be selected as 1:4 to 6 or 1:6 to 8.

[0069] In step 1) of this invention, sulfonyl fluoride is a gas, and there is usually no need to limit its amount. The timing of stopping the introduction of sulfonyl fluoride can be determined based on the erythritol conversion status in the GC.

[0070] In step 1) of this invention, the organic solvent is selected from one or more of dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), or diethyl carbonate (DEC).

[0071] In step 1) of the present invention, the reaction temperature is 20-50℃ and any value between them or any two values, and can be selected as 20-40℃, 40-50℃, 20-30℃, or 30-50℃.

[0072] In step 1) of this invention, the reaction time is 4 to 12 hours and any value between them or any two values, and can be selected as 4 to 8 hours or 8 to 12 hours.

[0073] In the preparation method of the composition provided by this invention, step 2) involves quenching the reaction with water, separating the organic phase, washing with water, and drying to obtain the crude product. Specifically:

[0074] In step 2) of this invention, water or a mixture of water and dichloromethane is added to quench the reaction; that is, water or a mixture of water and dichloromethane is added after the reaction is complete to quench the reaction. Preferably, a mixture of water and dichloromethane is added to quench the reaction, as the addition of dichloromethane facilitates solvent separation. When a mixture of water and dichloromethane is selected, for example, the mass ratio of water to dichloromethane is 2:1.

[0075] In step 2) of the present invention, the amount of water added in the quenching reaction is 1-2 times the mass of erythritol and any value between them or any two values, and can be selected as 1-1.5 times or 1.5-2 times.

[0076] In step 2) of the present invention, the amount of dichloromethane added is 1-2 times the mass of erythritol and any value between them or any two values, and can be selected as 1-1.5 times or 1.5-2 times.

[0077] In step 2) of this invention, the amount of water added during the washing process is 2-3 times the mass of erythritol and any value between them or any two values, and can be selected as 2-2.5 times or 2.5-3 times.

[0078] In step 2) of this invention, the drying process involves adding anhydrous magnesium sulfate and stirring thoroughly. The amount of anhydrous magnesium sulfate added is 0.2-0.5 times the mass of erythritol, or any value between them or any two values, and can be selected as 0.2-0.4 times, 0.4-0.5 times, 0.2-0.3 times, or 0.3-0.5 times.

[0079] In step 2) of this invention, the organic liquid is filtered after washing and drying.

[0080] In the preparation method of the composition provided by this invention, step 3) involves concentrating, crystallizing, and drying the crude product obtained in step 2) to obtain the composition. Specifically:

[0081] In step 3) of this invention, the concentration process concentrates the solution to 1 / 2 to 1 / 3 of its original volume and any value between them or any two values.

[0082] In step 3) of this invention, crystallization is carried out by cooling crystallization. The cooling crystallization temperature is 0-10℃ and any value between them or any two values, and can be selected as 0-5℃, 5-10℃, 0-3℃, 3-5℃, 5-8℃, or 8-10℃.

[0083] In step 3) of this invention, drying can be carried out by any of the common methods such as air drying, desiccation, and baking. Desiccation is preferred to improve efficiency.

[0084]

application

[0085] The present invention also provides the use of the compositions as described in the present invention and / or the compositions prepared by the preparation methods as described in the present invention in electrolytes.

[0086] Electrolyte

[0087] The present invention also provides an electrolyte comprising the composition as described in the present invention and / or a composition prepared by the preparation method described in the present invention.

[0088] Specifically: the electrolyte contains a cyclic sulfate compound as shown in formula (1), and also contains a sulfate compound as shown in formula (A) and / or a carbonate compound as shown in formula (B):

[0089]

Battery

[0090] The present invention also provides a battery comprising the electrolyte as described in the present invention.

[0091] The beneficial effects of the present invention will be further illustrated below with reference to the embodiments.

[0092] To make the inventive objectives, technical solutions, and beneficial effects of this invention clearer, the invention is further described in detail below with reference to embodiments. However, it should be understood that the embodiments of this invention are merely for illustrative purposes and not for limiting the invention, and the embodiments are not limited to those given in the specification. Unless otherwise specified, specific experimental or operational conditions in the embodiments were prepared under conventional conditions or according to the conditions recommended by the material supplier.

[0093] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this invention does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0094] In the following embodiments, unless otherwise specified, the reagents, materials and instruments used are commercially available or prepared according to conventional methods in the art.

[0095] Purity testing method: Agilent 8860 gas chromatograph; calculate the content of each substance based on the peak area ratio. Data overflow due to rounding during calculation or the total amount of each substance not exceeding 100% can be ignored.

[0096] Example 1

[0097] 100 g of erythritol (1.0 eq) and 165.7 g of triethylamine (2.0 eq) were added to a 1 L reaction flask, followed by the addition of 400 g of DMC and the introduction of sulfonyl fluoride. The reaction was carried out at 20-40 °C for 8.0 h. After erythritol conversion was completed according to GC, 200 g of water and 100 g of dichloromethane were added, and the mixture was stirred and separated. The organic phase was washed once with 100 g of water, dried over 20 g of anhydrous magnesium sulfate, filtered, and the filtrate was concentrated to about one-third of the solvent remaining. The mixture was cooled to 0-10 °C to crystallize, filtered, and dried under vacuum to obtain 96.6 g of white solid product, with a yield of 71%, purity of 99.61%, impurity A of 0.03%, and impurity B of 0.37%. The chromatogram of the sample is shown below. Figure 4 As shown. The chromatogram of the sample of impurity A, i.e., the compound represented by formula (A), is as follows. Figure 2 As shown. The chromatogram of the sample of impurity B, i.e., the compound represented by formula (B), is as follows. Figure 3 As shown.

[0098] Example 2

[0099] 100g erythritol (1.0 eq) and 206.4g NaHCO3 (3.0 eq) were added to a 1L reaction flask, followed by the addition of 400g DEC and the introduction of sulfonyl fluoride. The reaction was carried out at 20-40℃ for 12.0h. The reaction solution was filtered, and 100g water was added to the filtrate with stirring. The mixture was separated, and the organic phase was washed once more with 100g water. 20g anhydrous magnesium sulfate was added for drying, followed by filtration. The filtrate was concentrated to approximately one-third of the solvent remaining, cooled to 0-10℃ to crystallize, filtered, and dried to obtain 103.4g of a white solid product, with a yield of 76%, purity of 99.57%, impurity A of 0.06%, and impurity B of 0.36%. The chromatogram of the sample is shown below. Figure 5 As shown.

[0100] Example 3

[0101] 100 g of erythritol (1.0 eq) and 161.8 g of tetramethylethylenediamine (1.7 eq) were added to a 1 L reaction flask, along with 800 g of DMC. Sulfonyl fluoride gas was introduced, and the reaction was carried out at 20-40 °C with stirring for 4 h. After the reaction was complete, the mixture was filtered. 100 g of water was added to the filtrate, and the mixture was separated. The organic phase was washed once with 100 g of water, dried with 20 g of anhydrous magnesium sulfate, filtered, and concentrated until approximately one-third of the solvent remained. The mixture was cooled to 0-10 °C to crystallize, filtered, and dried under vacuum to obtain 115.6 g of a white solid product, with a yield of 85%, a purity of 99.54%, impurity A of 0.11%, and impurity B of 0.35%. The chromatogram of the sample is shown below. Figure 6 As shown.

[0102] Example 4

[0103] 100g erythritol (1.0 eq) and 173.6g Na2CO3 (2 eq) were added to a 1L reaction flask, followed by the addition of 400g DMC and the introduction of sulfonyl fluoride. The reaction was carried out at 20-40℃ for 12.0h. The reaction solution was filtered, and 100g water was added and stirred. The mixture was separated, and the organic phase was washed once with 100g water and dried over 20g anhydrous magnesium sulfate. The solution was filtered, and the filtrate was concentrated to about one-third of the solvent remaining. The solution was cooled to 0-10℃ to crystallize, filtered, and dried to obtain 95.2g of a white solid product, with a yield of 70%, a purity of 99.51%, impurity A of 0.14%, and impurity B of 0.35%. The chromatogram of the sample is shown below. Figure 7 As shown.

[0104] Example 5

[0105] 100 g erythritol (1.0 eq) and 129.5 g pyridine (2.0 eq) were added to a 1 L reaction flask, followed by 400 g DMC. Sulfonyl fluoride was bubbled through the mixture, and the reaction was carried out at 20-40 °C for 8.0 h. After filtration, 200 g water was added to the filtrate, and the mixture was stirred for 2 min. The liquid was separated, and the organic phase was washed once more with 100 g water. 20 g anhydrous magnesium sulfate was added for drying, and the mixture was filtered. The filtrate was concentrated to approximately one-third of the solvent remaining, cooled to 0-10 °C to crystallize, filtered, and dried to obtain 99.3 g of a white solid product. The yield was 73%, the purity was 99.94%, impurity A was 0.02%, and impurity B was 0.03%. The chromatogram of the sample is shown below. Figure 8 As shown.

[0106] Comparative Example

[0107] The cyclic sulfate compound of formula (1) was prepared using the same method as in Example 1 of CN 118825414 A.

[0108] At room temperature, cis-tetrahydrofuran-3,4-diol (20 g, 0.19 mol, 1.0 equiv) was dissolved in 200 mL of anhydrous acetonitrile, and N,N-thiodiimidazole (45.7 g, 0.23 mmol, 1.2 equiv) was added. The mixture was stirred at room temperature. After filtration, the filtrate was concentrated under reduced pressure. The residue was dissolved in dichloromethane and water, separated, and the organic phase was washed with water and sodium chloride, and dried over anhydrous magnesium sulfate. The organic phase was filtered, and the filtrate was concentrated under reduced pressure. The residue was dissolved in an appropriate amount of dichloromethane, cooled, and a solid precipitated. After filtration and vacuum drying, 23.0 g of white powder solid was obtained, with a yield of 72% and a purity of 99.1%. The impurities included 0.2% cis-tetrahydrofuran-3,4-diol and 0.7% imidazole.

[0109] To illustrate the specific effects of the composition in the electrolyte, the present invention also provides the following application examples. To more clearly demonstrate the role of each component in the composition in the electrolyte application system, the components in the compositions described in the following application examples, such as tetrahydrofuran-3,4-cyclic sulfate (the compound shown in formula (1)), erythrose bicyclic sulfate (the compound shown in formula (A)), and tetrahydrofuran-3,4-cyclic carbonate (the compound shown in formula (B)), are all commercially available or have been further purified, and their purity is ≥99.99%.

[0110] Comparative application examples

[0111] (1) Preparation of electrolyte:

[0112] An electrolyte (oxygen content <0.1 ppm, water content <0.1 ppm) was prepared in a glove box. Ethyl methyl carbonate (EMC) and ethylene carbonate (EC) were mixed at a volume ratio of 7:3 as an organic solvent, and a total of 100 mL was prepared. LiPF6 with a lithium salt molar concentration of 1.1 mol / L was added to this solvent. Then, 3% (by weight of solvent and lithium salt) of vinylene carbonate (VC) and 1% (by weight of propane sulfonate lactone (PS)) were added to the electrolyte, and the mixture was stirred until completely dissolved to obtain the lithium-ion battery electrolyte for the comparative application example.

[0113] (2) Preparation of lithium-ion batteries:

[0114] The lithium-ion battery used in this embodiment has lithium iron phosphate as the positive electrode active material and graphite as the negative electrode active material. After the battery undergoes processes such as slurry preparation, coating, rolling, die cutting, stacking, hot pressing, and packaging, a dry cell ready for electrolyte injection is obtained. The lithium-ion battery electrolyte of Application Example 1 is injected to obtain the lithium-ion battery C of the comparative application example.

[0115] Application Example 1

[0116] Unlike the comparative application example, 3% vinylene carbonate (VC), 1% propane sulfonate lactone (PS), and 1% tetrahydrofuran-3,4-cyclic sulfate (the compound shown in formula (1)) were added to the electrolyte to obtain the lithium-ion battery C1 of application example 1.

[0117] Application Example 2

[0118] Unlike the comparative application example, 3% vinylene carbonate (VC), 1% propane sulfonate lactone (PS), and 1% erythrosine bicyclic sulfate (the compound shown in formula (A)) were added to the electrolyte to obtain the lithium-ion battery C2 of application example 2.

[0119] Application Example 3

[0120] Unlike the comparative application example, 3% vinylene carbonate (VC), 1% propane sulfonate lactone (PS), and 1% tetrahydrofuran-3,4-cyclic carbonate (the compound shown in formula (B)) were added to the electrolyte to obtain the lithium-ion battery C3 of application example 3.

[0121] Application Example 4

[0122] Unlike the comparative application example, the lithium-ion battery C4 of application example 4 was obtained by adding 3% vinylene carbonate (VC), 1% propane sulfonate lactone (PS), 0.9% tetrahydrofuran-3,4-cyclic sulfate (the compound shown in formula (1)) and 0.1% erythrose bicyclic sulfate (the compound shown in formula (A)) to the electrolyte.

[0123] Application Example 5

[0124] Unlike the comparative application example, 3% vinylene carbonate (VC), 1% propane sulfonate lactone (PS), 0.9% tetrahydrofuran-3,4-cyclic sulfate (the compound shown in formula (1)) and 0.1% tetrahydrofuran-3,4-cyclic carbonate (the compound shown in formula (B)) were added to the electrolyte to obtain the lithium-ion battery C5 of application example 5.

[0125] Application Example 6

[0126] Unlike the comparative application example, the lithium-ion battery C6 of application example 6 was obtained by adding 3% vinylene carbonate (VC), 1% propane sulfonate lactone (PS), 0.99% tetrahydrofuran-3,4-cyclic sulfate (the compound shown in formula (1)), 0.005% erythrose bicyclic sulfate (the compound shown in formula (A)) and 0.005% tetrahydrofuran-3,4-cyclic carbonate (the compound shown in formula (B)) to the electrolyte.

[0127] Application Example 7

[0128] Unlike the comparative application example, the lithium-ion battery C7 of application example 7 was obtained by adding 3% vinylene carbonate (VC), 1% propane sulfonate lactone (PS), 0.995% tetrahydrofuran-3,4-cyclic sulfate (the compound shown in formula (1)), 0.002% erythrose bicyclic sulfate (the compound shown in formula (A)) and 0.003% tetrahydrofuran-3,4-cyclic carbonate (the compound shown in formula (B)) to the electrolyte.

[0129]

[0130] The batteries obtained from Comparative Application Examples and Application Examples 1-7 were subjected to the following experiments. The experimental instruments were a Shenzhen Xinwei CT-4008Tn-5V6A-S1 battery tester and an MGDW-225-40 high and low temperature test chamber. The test results are shown in […]. Figures 9-14 .

[0131] (1) High-temperature storage performance test: Compare the batteries obtained from application examples and application examples 1 to 7. At 25°C, charge the batteries at 1C constant current and constant voltage to a voltage of 3.65V and a cutoff current of 0.05C, and record the 1C capacity Q. Store the fully charged batteries at 60°C for 14 days, and record the 1C discharge capacity Q1 at 25°C. Charge the batteries at 1C constant current and constant voltage to a voltage of 3.65V and a cutoff current of 0.05C, and then discharge them at 1C constant current to 2.5V, and record the 1C discharge capacity Q2. Calculate the capacity retention rate and recovery rate of the batteries after storage.

[0132] The calculation formulas are as follows:

[0133] Storage capacity retention rate = Q1 / Q × 100%; Storage capacity recovery rate = Q2 / Q × 100%.

[0134] (2) DC Impedance (DCIR) Test: After the batteries obtained from the comparative application examples and application examples 1 to 7 were formed and capacity tested, charge and discharge pulse tests were performed at 25°C. The charging current was 2.75A, the voltage before charging was V1, and the voltage after charging was V2; the discharge current was 3A, the voltage before discharging was V3, and the voltage after discharging was V4; the charge and discharge pulse time was 10s.

[0135] The calculation formulas are as follows:

[0136] Charging DCIR = (V2 - V1) / 2.75; Discharging DCIR = (V3 - V4) / 3.

[0137] (3) Low-temperature discharge performance test: Compare the batteries obtained from application examples and application examples 1 to 7. At 25°C, charge the batteries at 1C constant current and constant voltage to a voltage of 3.65V and a cutoff current of 0.05C, and then discharge them at 1C constant current to 2.5V. Record the discharge capacity Q3. At 25°C, charge the batteries at 1C constant current and constant voltage to a voltage of 3.65V and a current of 0.05C, and then discharge them at -10°C at 1C constant current to 2.5V. Record the discharge capacity Q4. Calculate the low-temperature discharge capacity retention rate of the battery = Q4 / Q3×100%.

[0138] (4) Rate performance test: After formation and capacity testing, the batteries obtained from the comparative application examples and application examples 1 to 7 were charged to 3.65V by constant current at 0.33C, 0.5C, 1C, 2C and 3C respectively, and discharged to 2.5V by constant current at 1C respectively, to complete the double charge test; and charged to 3.65V by constant current at 1C, and discharged to 2.5V by constant current at 0.33C, 0.5C, 1C, 3C and 4C respectively, to complete the double discharge test.

[0139] (5) High-temperature cycle performance test: Compare the batteries obtained from Application Examples 1 to 7 with those obtained from Application Examples 1. Under conditions of 45°C, charge the batteries at 1C constant current and constant voltage to a voltage of 3.65V and a cutoff current of 0.05C, let them rest for 10 minutes, and then discharge them at 1C constant current to a voltage of 2.5V. This constitutes one charge-discharge cycle. The obtained batteries are then subjected to cyclic charge-discharge at 45°C. The cycle ends when the discharge capacity is lower than 80% of the initial discharge capacity.

[0140] Combining the above application examples Figures 9-14It can be seen that the cyclic sulfate compound shown in formula (1), as an additive in lithium-ion battery electrolyte, is beneficial for improving the battery's performance in high-temperature storage, DC resistance, low-temperature discharge, rate capability, and high-temperature cycling at different temperatures. Meanwhile, the sulfate compound shown in formula (A) and the carbonate compound shown in formula (B), as additives in lithium-ion battery electrolyte, both improve the aforementioned battery performance. Furthermore, when they are mixed, within a larger mixing range, with the same addition amount, the mixture shows better performance improvement in battery performance compared to the single component compound shown in formula (1). Therefore, a composition containing the sulfate compound shown in formula (A) and / or the carbonate compound shown in formula (B) can be directly applied to lithium-ion battery electrolytes.

[0141] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0142] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A composition, characterized in that, Composed of a cyclic sulfate compound represented by formula (1), a sulfate compound represented by formula (A), and / or a carbonate compound represented by formula (B); （1） （A） （B）； The total content of the sulfate ester compound shown in formula (A) and the carbonate compound shown in formula (B) in the composition is greater than 1 ppm and less than 10,000 ppm, where ppm is a mass reference.

2. The composition according to claim 1, characterized in that, The total content of the sulfate ester compound shown in formula (A) and the carbonate compound shown in formula (B) in the composition is greater than 1 ppm and less than 5000 ppm, where ppm is a mass reference.

3. The composition according to claim 1, characterized in that, The cyclic sulfate compound represented by formula (1) is present in the composition at a content of 99% or more by mass.

4. The composition according to claim 3, characterized in that, The cyclic sulfate compound represented by formula (1) is present in the composition at a concentration of 99.5% or more by mass.

5. A method for preparing the composition according to any one of claims 1 to 4, characterized in that, The preparation method includes the following steps: 1) Using erythritol and sulfonyl fluoride as raw materials, an acid-binding agent is added, and the reaction is carried out in an organic solvent; 2) Quench the reaction with water, separate the organic phase, wash with water and dry to obtain the crude product; 3) The crude product obtained in step 2) is concentrated, crystallized, and dried to obtain the composition.

6. The method for preparing the composition according to claim 5, characterized in that, It also includes one or more of the following conditions: A1) In step 1), the molar ratio of erythritol to the acid-binding agent is 1:1.7~3; A2) In step 1), the acid-binding agent is selected from one or more of triethylamine, NaHCO3, tetramethylethylenediamine, and pyridine; A3) In step 1), the mass ratio of erythritol to organic solvent is 1:4~8; A4) In step 1), the organic solvent is selected from one or more of dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate; A5) In step 1), the reaction temperature is 20-50℃; A6) In step 1), the reaction time is 4-12 hours; In step 2) of A7), water or a mixture of water and dichloromethane is added to quench the reaction. In step 2) of A8, the amount of water added during the washing process is 2-3 times the mass of the erythritol; In step 2) of A9), the drying process involves adding anhydrous magnesium sulfate and stirring thoroughly. In step 2) of A10, the organic liquid is filtered after washing and drying. In step 3) of A11), the concentration process concentrates the solution to 1 / 2 to 1 / 3 of its original volume; In step 3) of A12), crystallization is performed using cooling crystallization; In step 3) of A13, drying is selected from any one of air drying, vacuum drying, or oven drying.

7. The method for preparing the composition according to claim 6, characterized in that, It also includes one or more of the following conditions: A71) In feature A7), a mixture of water and dichloromethane is added during the water quenching reaction; A72) In feature A7), the amount of water added in the quenching reaction is 1-2 times the mass of the erythritol; A73) In feature A7), the amount of dichloromethane added is 1-2 times the mass of erythritol; A91) In feature A9), the amount of anhydrous magnesium sulfate added is 0.2-0.5 times the mass of erythritol; In feature A12), the temperature for cooling crystallization is 0-10°C.

8. The use of the composition according to any one of claims 1 to 4 and / or the composition prepared by the preparation method according to any one of claims 5 to 7 in an electrolyte.

9. An electrolyte, characterized in that, The electrolyte comprises the composition according to any one of claims 1 to 4 and / or the composition prepared by the preparation method according to any one of claims 5 to 7.

10. A battery, characterized in that, The battery includes the electrolyte as described in claim 9.

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