WO2019061831A1 - Cyclic disulfonic acid silyl ester and preparation method therefor - Google Patents

Abstract

The present invention discloses a cyclic disulfonic acid silyl ester with a structure as shown in structural formula (A). A preparation method therefor comprises steps of: reacting methylene disulfonic acid or a methylene disulfonate of general formula (I) with a dihydrocarbyl di-active functional group silane of general formula (II), a dihydrocarbyl cyclosiloxane of general formula (III), or a dihydrocarbyl cyclosilazane of general formula (IV) in a solvent at a specific molar ratio, controlling the temperature and time of the reaction, and separating and removing the solvent and by-products after completion of the reaction, to give the cyclic disulfonic acid silyl ester. The present invention adopts a special raw material selection and synthesis process design and prepares novel cyclic disulfonic acid silyl esters having different substituents, with the ability to effectively improve normal temperature and high temperature cycle performance and high temperature storage performance of lithium secondary batteries and reduce battery thickness expansion in high-temperature storage processes. The preparation method therefor has simple process steps and strong implementability, and the obtained product has high purity, with chromatographic purity of over 99%, and broad market prospects.

Description

Cyclic disulfonate silyl ester and preparation method thereof Technical field

The invention relates to the technical field of preparation of lithium battery electrolyte additive, in particular to a cyclic silicon disulfonate and a preparation method thereof.

Background technique

Sulfonyl compounds, especially sulfonate compounds, have been extensively developed and synthesized in the 1940s as an important pharmaceutical intermediate. With the increasing popularity of small electronic devices such as smart phones, laptops and tablets, the development and use of lithium batteries has entered a booming stage; while pursuing their endurance capabilities, lightweight (portable) and environmentally friendly (Circularity) and safety (stability) are also receiving increasing attention. At the same time, the depletion of petrochemical energy and its non-renewability make lithium batteries, which are energy carriers, widely used in small vehicles, such as electric bicycles and electric vehicles, which have the same standards for lithium batteries. In this context, its use as a lithium battery electrolyte additive is also being developed and used.

The synthesis and use of chain disulfonates, cyclic sulfonates and chain sulfonate silyl esters have been reported in the literature.

1. Patent CN1894822A discloses a chain disulfonate, a cyclic sulfonate and a cyclic disulfonate as a lithium manganese composite battery having a spinel structure, which is used as a specific lithium salt as an electrolyte. In the case of adding 0.1% to 5% by weight of the above substance, it is effective to form a passivation film on the electrode and suppress decomposition of the electrolyte; and effectively improve the charge and discharge efficiency, cycle property and storage capacity of the battery without impairing the battery.

2. Patent CN201110239710 discloses a simple and effective synthesis method of disulfonate specifically methylene methane disulfonate: methane disulfonic acid, phosphorus pentoxide and formaldehyde compounds, which are ground in acetone, acetonitrile and other grinding aids. The reaction is carried out at 0 to 80 ° C to obtain the above disulfonate; the compound It can be used as a lithium battery electrolyte additive, especially in a secondary battery using lithium manganate as a positive electrode material, which can effectively prevent manganese from being adsorbed on the negative electrode material, thereby improving the cycle life of the battery. In addition, the synthesis method of the chain sulfonate is disclosed in J. Am. Pham. Assoc. Vol. 126. Pages 485-493 (1937) and the like; the synthesis method of the cyclic dicarboxylic acid ester is disclosed in Japan. Patent No. 5-44946 and U.S. Patent No. 4,950,768.

3. Patent CN1822423A discloses the use of a chain sulfonate as a lithium battery electrolyte additive, specifically trimethylsilyl trifluoromethane sulfonate, which is specific to a specific lithium salt such as lithium hexafluorophosphate, etc. A mixed electrolyte such as dimethyl carbonate or the like is added, and 0.1% to 10%, preferably 0.1% to 5% by mass of the compound is added to form a film on the surface of the negative electrode, thereby improving the electrochemical characteristics of the electrolyte at a low temperature.

4. Patent CN101197456A also discloses a method for applying a chain sulfonate as an electrolyte additive for a lithium battery.

At present, the preparation of silyl disulfonate has rarely been reported.

Summary of the invention

The technical problem mainly solved by the present invention is to provide a cyclic silicon disulfonate and a preparation method thereof.

In order to solve the above technical problem, one technical solution adopted by the present invention is to provide a cyclic silicon disulfonate, which comprises the following structural formula:

Wherein R ₁ and R ₂ are the same or different hydrocarbon groups.

In a preferred embodiment of the invention, the hydrocarbon group represented by R ₁ and R ₂ includes a methyl group, an ethyl group, a vinyl group or a phenyl group.

In order to solve the above technical problem, another technical solution adopted by the present invention is to provide a circular two The preparation method of the silicon sulfonate comprises the following steps:

Methylene disulfonic acid or a methylene disulfonate of the formula (I) with a dihydrocarbyl difunctional functional silane of the formula (II), a dihydrocarbyl cyclosiloxane of the formula (III) or a formula The dihydrocarbyl cyclosilazane of (IV) is reacted in a solvent at a certain molar ratio to control the temperature and time of the reaction. After the reaction is completed, the solvent and by-products are separated and removed to obtain the cyclic silicon disulfonate;

Wherein the structural formula of the methylene disulfonate of the formula (I) is:

The structural formula of the dihydrocarbyl diactive functional group silane of the formula (II) is:

The structural formula of the dihydrocarbyl cyclosiloxane of the formula (III) is:

The structural formula of the dihydrocarbylcyclosilazane of the formula (IV) is:

In the above formula, M is a monovalent metal ion, and Z is a divalent metal ion;

X, Y are the same or different hydrolyzable reactive functional groups;

R ₃ is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a phenyl group or an allyl group;

n is an integer of 3 to 7.

In a preferred embodiment of the present invention, the monovalent metal ion is an alkali metal ion or a transition metal ion; the divalent metal ion is an alkaline earth metal ion or a transition metal ion; and the alkali metal ion is a lithium ion, a sodium ion or a potassium ion; the alkaline earth metal ion is a magnesium ion, a calcium ion, a barium ion or a barium ion; and the transition metal ion is a ferrous ion, a zinc ion, a copper ion or a silver ion.

In a preferred embodiment of the present invention, the easily hydrolyzable reactive functional group is a halogen, an alkoxy group, an acyloxy group, an amide group, an alkenyloxy group, an amine group, a decyl group or a hydroxylamine group; wherein the halogen is fluorine , chlorine, bromine or iodine.

In a preferred embodiment of the invention, the reaction temperature is from -20 ° C to 200 ° C and the time is from 0.5 to 50 h.

In a preferred embodiment of the present invention, the molar ratio of the methylene disulfonic acid or methylene disulfonate to the dihydrocarbyl difunctional functional group silane and the solvent is from 1:0.1 to 10:3 to 50.

In a preferred embodiment of the present invention, the molar ratio of the methylene disulfonic acid or methylene disulfonate to the dihydrocarbyl cyclosiloxane or the dihydrocarbyl cyclosilazane and the solvent is 1:0.1 5:3~50.

In a preferred embodiment of the present invention, the solvent is one of an aliphatic hydrocarbon, a halogenated hydrocarbon, an aromatic hydrocarbon, an ether, a ketone, an ester, an amide, a nitrile, and an imidazolinone solvent. Species or combinations of two or more.

In a preferred embodiment of the present invention, the aliphatic hydrocarbon solvent is n-hexane, cyclohexane or heptane; the halogenated hydrocarbon solvent is dichloromethane, dichloroethane or dichloropropane; The aromatic hydrocarbon solvent is toluene, chlorobenzene, fluorobenzene or xylene; the ether solvent is methyl tert-butyl ether, ethylene glycol dimethyl ether, dioxolane or dioxane; the ketone The solvent is acetone, methyl ethyl ketone, cyclohexanone or methyl isobutyl ketone; the ester solvent is methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, methyl propionate, and propionic acid An ester or a propyl propionate; the amide solvent is dimethylformamide; the nitrile solvent is acetonitrile; and the imidazolinone solvent is dimethylimidazolidinone.

The invention has the beneficial effects that: the invention selects and obtains cyclic silicon disulfonate having different substituents through special material selection and synthesis process design, and can effectively improve the normal temperature and high temperature cycle performance of the lithium secondary battery. And high-temperature storage performance, reducing the thickness expansion of the battery in the high-temperature storage process; the preparation method has simple process steps, strong implementability, high purity of the obtained product, chromatographic purity of more than 99%, and has broad market prospects.

Detailed ways

The preferred embodiments of the present invention are described in detail below, so that the advantages and features of the present invention can be more readily understood by those skilled in the art.

Embodiments of the invention include:

The invention discloses a cyclic silicon disulfonate, which comprises the following structural formula:

Wherein R ₁ and R ₂ are the same or different hydrocarbyl groups, and the hydrocarbyl group includes a methyl group, an ethyl group, a vinyl group or a phenyl group.

The preparation method of the above cyclic silicon disulfonate includes the following steps:

Methylene disulfonic acid or a methylene disulfonate of the formula (I) and a dihydrocarbyl diactive functional silane of the formula (II) in a solvent, according to methylene disulfonic acid or methylene di The molar ratio of the sulfonate to the dihydrocarbyl difunctional functional group silane and the solvent is from 1:0.1 to 10:3 to 50;

Or methylene disulfonic acid or a methylene disulfonate of the formula (I) and a dihydrocarbyl cyclosiloxane of the formula (III) in a solvent, according to methylene disulfonic acid or methylene The molar ratio of the disulfonate to the dihydrocarbyl cyclosiloxane and the solvent is from 1:0.1 to 5:3 to 50;

Or methylene disulfonic acid or a methylene disulfonate of the formula (I) and a dihydrocarbyl group of the formula (IV) The cyclosilazane is reacted in a molar ratio of methylene disulfonic acid or methylene disulfonate to dihydrocarbyl cyclosilazane and a solvent of from 1:0.1 to 5:3 to 50;

Controlling the reaction temperature is -20 ° C ~ 200 ° C, the time is 0.5 ~ 50h, after the end of the reaction, the solvent and by-products are separated and removed to obtain the cyclic silicon disulfonate of the above structural formula;

among them,

The structural formula of the methylene disulfonate of the formula (I) is:

The structural formula of the dihydrocarbyl diactive functional group silane of the formula (II) is:

The structural formula of the dihydrocarbyl cyclosiloxane of the formula (III) is:

The structural formula of the dihydrocarbylcyclosilazane of the formula (IV) is:

In the above formula, M is a monovalent metal ion, and Z is a divalent metal ion;

Specifically, the monovalent metal ion is an alkali metal ion or a transition metal ion; the divalent metal ion is an alkaline earth metal ion or a transition metal ion; and the alkali metal ion is a lithium ion, a sodium ion or a potassium ion; The alkaline earth metal ion is a magnesium ion, a calcium ion, a barium ion or a barium ion; the transition metal ion is a ferrous ion, a zinc ion, a copper ion or a silver ion.

X, Y are the same or different hydrolyzable reactive functional groups; the easily hydrolyzable reactive functional groups are halogens, alkanes An oxy group, an acyloxy group, an amide group, an alkenyloxy group, an amine group, a decyl group or a hydroxylamine group; wherein the halogen is fluorine, chlorine, bromine or iodine.

R ₃ is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a phenyl group or an allyl group;

n is an integer of 3 to 7.

The solvent is one or a combination of two or more of aliphatic hydrocarbons, halogenated hydrocarbons, aromatic hydrocarbons, ethers, ketones, esters, amides, nitriles, and imidazolinones.

Specifically, the aliphatic hydrocarbon solvent is n-hexane, cyclohexane or heptane;

The halogenated hydrocarbon solvent is dichloromethane, dichloroethane or dichloropropane;

The aromatic hydrocarbon solvent is toluene, chlorobenzene, fluorobenzene or xylene;

The ether solvent is methyl tert-butyl ether, ethylene glycol dimethyl ether, dioxolane or dioxane;

The ketone solvent is acetone, methyl ethyl ketone, cyclohexanone or methyl isobutyl ketone;

The ester solvent is methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, methyl propionate, ethyl propionate or propyl propionate;

The amide solvent is dimethylformamide;

The nitrile solvent is acetonitrile;

The imidazolinone solvent is dimethylimidazolidinone.

Example 1

1 mol of sodium methyldisulfonate was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow and dehydrated under a negative pressure for 2 hours. After cooling to room temperature, the vacuum was removed by a nitrogen bag, and a solvent which had been dehydrated to a water content of 5 ppm or less was quickly added: 1 mol of fluorobenzene, 1 mol of dichloroethane and 1 mol of dimethylformamide, and 1 mol of dimethyldichlorosilane was added dropwise with stirring. After the completion of the dropwise addition, stirring was continued for 1 hour, then heated to 80-85 ° C for refluxing for 12 hours, cooled to about 10 ° C, filtered, and the filtrate was transferred to a rotary evaporator to distill off dichloroethane and dimethyl at a negative pressure. Formamide, after repeated recrystallization and GC-MS analysis, the structural formula is

The target product was 98 g with a purity of 99.6%.

Example 2

1 mol of silver disulfonate was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow and dehydrated under a negative pressure for 2 hours. After cooling to room temperature, the vacuum was removed by a nitrogen bag, and 50 mol of dioxane which had been dehydrated to a moisture content of 5 ppm or less was quickly added, and 5 mol of methylvinyldibromosilane was added dropwise with stirring. After the completion of the dropwise addition, stirring was continued for 1 hour, followed by heating. The reaction was refluxed at 100-105 ° C for 25 hours, cooled to about 5 ° C, suction filtered, and the filtrate was transferred to a rotary evaporator to distill off the dioxane and excess methylvinyldibromosilane under a vacuum, and recrystallized several times. Purification and GC-MS analysis, the structural formula is

The target product was 116 g with a purity of 99.3%.

Example 3

1 mol of bismuth methyldisulfonate was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow and dehydrated under negative pressure for 2 hours. After cooling to room temperature, the vacuum was removed by a nitrogen bag, and 15 mol of N,N-dimethylimidazolidinone which had been dehydrated to 5 ppm or less was quickly added, and 10 mol of methylphenyldichlorosilane was added dropwise with stirring. Stir for 1.5 hours, then heat to 190-200 ° C for 8 hours, cool to about 20 ° C, press filter, the filtrate is transferred to a rotary evaporator to remove fluorobenzene, N, N-dimethylimidazolidinone and excess Methylphenyldichlorosilane, after repeated recrystallization purification and LC-MS analysis, the structural formula is

The target product was 76 g with a purity of 99.7%.

Example 4

1 mol of lithium methyldisulfonate was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. Cool down to -20 ° C, use a nitrogen bag to eliminate the vacuum, and quickly add the solvent that has been dehydrated to less than 5 ppm of water: 10 mol of acetonitrile and 10 mol of ethyl propionate, and add 1 mol of diphenyldifluorosilane dropwise with stirring. After stirring for 20 hours, press filtration, the filtrate was transferred to a rotary evaporator and the acetonitrile and ethyl propionate were distilled off under negative pressure. After repeated recrystallization and LC-MS analysis, the structural formula was obtained.

The target product was 98 g with a purity of 99.1%.

Example 5

3 mol of zinc disulfonate was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under negative pressure. After cooling to room temperature, the vacuum was removed with a nitrogen bag, and the solvent which had been dehydrated to a moisture content of 5 ppm or less was quickly added: n-heptane 5 mol and methyl isobutyl ketone 60 mol, 0.3 mol of diethylchloroiodosilane was added dropwise with stirring, and the addition was completed. After that, stirring was continued for 1 hour, then heated to 60-70 ° C for 50 hours, cooled to about 0 ° C, filtered, and the filtrate was transferred to a rotary evaporator to remove n-heptane and methyl isobutyl ketone under a vacuum. Multiple recrystallization and GC-MS analysis, the structural formula is

The target product was 32 g with a purity of 99.2%.

Implementation 6

1 mol of methyl disulfonic acid and 1 mol of chlorobenzene are azeotropically dehydrated to a water content of 5 ppm or less. Cool down to room temperature, remove the vacuum with a nitrogen bag, and quickly add a solvent that has been dehydrated to a moisture content of 5 ppm or less: 1 mol of dichloroethane and 1 mol of dimethylformamide, and add 1 mol of dimethylmethoxychlorosilane dropwise with stirring. After completion, stirring is continued for 1 hour, then heated to 80-85 ° C for refluxing for 12 hours, cooled to about 10 ° C, filtered, and the filtrate is transferred to a rotary evaporator to distill off dichloroethane and dimethylformamide under a vacuum. After repeated recrystallization and GC-MS analysis, the structural formula is

The target product was 89 g with a purity of 99.7%.

Example 7

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. After cooling to room temperature, the vacuum was removed by a nitrogen bag, and 50 mol of dioxane which had been dehydrated to a moisture content of 5 ppm or less was quickly added, and 5 mol of methylvinyldiacetoxysilane was added dropwise with stirring. After the dropwise addition, stirring was continued for 1 hour. Then, the mixture is heated to 100-105 ° C for refluxing for 25 hours, cooled to about 5 ° C, suction filtered, and the filtrate is transferred to a rotary evaporator to distill off dioxane and excess methylvinyldibromosilane and low-boiling side. The product was purified by repeated recrystallization and GC-MS analysis to obtain the structural formula.

The target product was 119 g with a purity of 99.3%.

Example 8

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. After cooling to room temperature, the vacuum was removed by a nitrogen bag, and 15 mol of N,N-dimethylimidazolidinone which had been dehydrated to a moisture content of 5 ppm or less was quickly added, and 10 mol of methylphenyldimethylamidosilane was added dropwise with stirring. Stirring for 1.5 hours, then heating to 190-200 ° C for 8 hours, cooling to about 20 ° C, pressure filtration, the filtrate was transferred to a rotary evaporator to remove fluorobenzene, N, N-dimethylimidazolidinone under negative pressure. And an excess of methylphenyldimethylamidosilane, after repeated recrystallization purification and LC-MS analysis, the structural formula is

The target product was 68 g with a purity of 99.4%.

Example 9

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. Cool down to -20 ° C, use a nitrogen bag to eliminate the vacuum, and quickly add the solvent that has been dehydrated to less than 5 ppm of water: 10 mol of acetonitrile and 10 mol of ethyl propionate, and add 1 mol of diphenyldimethylaminosilane dropwise with stirring. Stirring was continued for 20 hours, pressure filtration, and the filtrate was transferred to a rotary evaporator to remove acetonitrile and ethyl propionate under low pressure and low-boiling by-products. After repeated recrystallization and LC-MS analysis, the structure was obtained.

The target product was 101 g, and the purity was 99.2%.

Example 10

3 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. After cooling to room temperature, the vacuum was purged with a nitrogen bag, and the solvent which had been dehydrated to a moisture content of 5 ppm or less was quickly added: n-heptane 5 mol and methyl isobutyl ketone 60 mol, and 0.3 mol of diethyldipropoxysilane was added dropwise with stirring. After the completion of the dropwise addition, stirring was continued for 1 hour, then heating to 60-70 ° C for 50 hours, cooling to about 0 ° C, pressure filtration, and the filtrate was transferred to a rotary evaporator to remove n-heptane and methyl isobutyl at a negative pressure. Ketone, after repeated recrystallization and GC-MS analysis, to obtain the structural formula

The target product was 35 g with a purity of 99.5%.

Example 11

1 mol of methyl disulfonic acid and 1 mol of chlorobenzene are azeotropically dehydrated to a water content of 5 ppm or less. Cool down to room temperature, remove the vacuum with a nitrogen bag, and quickly add a solvent that has been dehydrated to a moisture content of 5 ppm or less: 1 mol of dichloroethane and 1 mol of dimethylformamide, and add 5 mol of hexamethylcyclotrisiloxane dropwise with stirring. After completion, stirring is continued for 1 hour, then heated to 80-85 ° C for refluxing for 12 hours, cooled to about 10 ° C, filtered, and the filtrate is transferred to a rotary evaporator to distill off dichloroethane and dimethylformamide under a vacuum. , hexamethylcyclotrisiloxane and low boiling by-products, after repeated recrystallization and GC-MS analysis, to obtain the structural formula

The target product was 99 g with a purity of 99.5%.

Example 12

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. After cooling to room temperature, the vacuum was removed by a nitrogen bag, and 50 mol of dioxane which had been dehydrated to a water content of 5 ppm or less was quickly added, and 2 mol of 1,3,5,7-tetramethyl-1,3,5,7-tetra was added dropwise with stirring. Vinylcyclotetrasiloxane, after the addition is completed, stirring is continued for 1 hour, then heated to 100-105 ° C for refluxing for 25 hours, cooled to about 5 ° C, suction filtered, and the filtrate is transferred to a rotary evaporator for vacuum distillation. Dioxane and excess 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane and low-boiling by-products, purified by multiple recrystallizations and GC- MS analysis, get the structural formula

The target product was 104 g with a purity of 99.6%.

Example 13

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. After cooling to room temperature, the vacuum was purged with a nitrogen bag, and 15 mol of N,N-dimethylimidazolidinone which had been dehydrated to a moisture content of 5 ppm or less was quickly added, and 0.1 mol of 1,3,5,7-tetramethyl-1 was added dropwise with stirring. 3,5,7-tetraphenylcyclotetrasiloxane, after the addition is completed, stirring is continued for 1.5 hours, then heated to 190-200 ° C for 8 hours, cooled to about 20 ° C, pressure-filtered, and the filtrate is transferred to rotary evaporation. The fluorobenzene and N,N-dimethylimidazolidinone were distilled off under negative pressure, and were recrystallized and purified by LC-MS to obtain the structural formula.

The target product was 46 g with a purity of 99.3%.

Example 14

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. Cool down to -20 ° C, use a nitrogen bag to eliminate the vacuum, and quickly add the solvent that has been dehydrated to less than 5 ppm of water: 10 mol of acetonitrile and 10 mol of ethyl propionate, and 0.2 mol of octaphenylcyclotetrasiloxane is added dropwise with stirring. After that, stirring was continued for 20 hours, pressure filtration, and the filtrate was transferred to a rotary evaporator to remove acetonitrile and ethyl propionate and low-boiling by-products under reduced pressure. After repeated recrystallization and LC-MS analysis, the structural formula was obtained.

The target product was 51 g with a purity of 99.7%.

Example 15

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. Cool down to room temperature, remove the vacuum with a nitrogen bag, and quickly add a solvent that has been dehydrated to a moisture content of 5 ppm or less: 2 mol of n-heptane and 20 mol of methyl isobutyl ketone, and 0.2 mol of decavinylcyclopentasiloxane is added dropwise with stirring. After the addition is completed, stirring is continued for 1 hour, then heating to 60-70 ° C for 50 hours, cooling to about 0 ° C, pressure filtration, and the filtrate is transferred to a rotary evaporator to remove n-heptane and methyl isobutyl ketone under a vacuum. , after repeated recrystallization and GC-MS analysis, the structural formula is obtained.

The target product was 37 g with a purity of 99.6%.

Example 16

1 mol of methyl disulfonic acid and 1 mol of chlorobenzene are azeotropically dehydrated to a water content of 5 ppm or less. Cool down to room temperature, remove the vacuum with a nitrogen bag, and quickly add a solvent that has been dehydrated to a moisture content of 5 ppm or less: 1 mol of dichloroethane and 1 mol of dimethylformamide, and add 5 mol of hexamethylcyclotrisilazane dropwise with stirring. After completion, stirring is continued for 1 hour, and then heated to 80-85 ° C for refluxing for 12 hours. The generated ammonia gas is absorbed, cooled to about 10 ° C, filtered, and the filtrate is transferred to a rotary evaporator to remove dichloroethane under a vacuum. , dimethylformamide, hexamethylcyclotrisilazane and low-boiling by-products, after repeated recrystallization and GC-MS analysis, the structural formula is obtained.

The target product was 99 g with a purity of 99.3%.

Example 17

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. After cooling to room temperature, the vacuum was removed by a nitrogen bag, and 50 mol of dioxane which had been dehydrated to a moisture content of 5 ppm or less was quickly added, and 2 mol of octamethylcyclotetrasilyl nitrogen was added dropwise with stirring. After the completion of the dropwise addition, stirring was continued for 1 hour, followed by heating. The reaction was refluxed at 100-105 ° C for 25 hours, the ammonia gas generated was absorbed, the system was cooled to about 5 ° C, suction filtration, and the filtrate was transferred to a rotary evaporator to remove dioxane and excess octamethylcyclotetraethylene under a vacuum. Silica nitrogen and low-boiling by-products, after repeated recrystallization and GC-MS analysis, the structural formula is obtained. The target product was 104 g with a purity of 99.5%.

Example 18

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. After cooling to room temperature, the vacuum was removed by a nitrogen bag, and 15 mol of N,N-dimethylimidazolidinone which had been dehydrated to a moisture content of 5 ppm or less was quickly added, and 0.1 mol of dodecamethylcyclotetrasilazane was added thereto with stirring. Stirring was continued for 1.5 hours, then heated to 190-200 ° C for 8 hours, cooled to about 20 ° C, pressure filtered, and the filtrate was transferred to a rotary evaporator to remove fluorobenzene and N,N-dimethylimidazolidinone under a vacuum. After repeated recrystallization and LC-MS analysis, the structure is obtained.

The target product was 32 g with a purity of 99.7%.

Example 19

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. Cool down to -20 ° C, use a nitrogen bag to eliminate the vacuum, and quickly add a solvent that has been dehydrated to a moisture content of 5 ppm or less: 10 mol of acetonitrile and 10 mol of ethyl propionate, and 0.2 mol of 1,3,5,7-tetramethyl-1 is added with stirring. 3,5,7-tetraphenylcyclotetrasilazane, after the addition, stirring is continued for 20 hours, the generated ammonia gas is absorbed, filtered, and the filtrate is transferred to a rotary evaporator to remove acetonitrile and ethyl propionate under a vacuum. And low boiling by-products, after repeated recrystallization and LC-MS analysis, the structural formula is obtained.

The target product was 62 g with a purity of 99.7%.

Example 20

1 mol of methyl disulfonic acid was placed in a three-necked flask equipped with a thermometer, a magnetic stirrer, a reflux condenser, and a constant pressure dropping funnel, and heated in an oil bath at about 100 ° C under a small nitrogen flow for 2 hours under vacuum. Cool down to room temperature, remove the vacuum with a nitrogen bag, and quickly add a solvent that has been dehydrated to a moisture content of 5 ppm or less: 2 mol of n-heptane and 20 mol of methyl isobutyl ketone, and 0.25 mol of 1,3,5,7-tetramethyl is added dropwise with stirring. -1,3,5,7-tetravinylcyclotetrasilazane, after the addition is completed, stirring is continued for 1 hour, and then heated to 60 to 70 ° C for 50 hours to absorb the generated ammonia gas, and the system is cooled to 0 ° C. Left and right, pressure filtration, the filtrate is transferred to a rotary evaporator and the n-heptane and methyl isobutyl ketone are distilled off under negative pressure. After repeated recrystallization and GC-MS analysis, the structure is obtained.

The target product was 42 g with a purity of 99.4%.

The above compound was added to an electrolyte for use in a lithium secondary battery, and relevant performance tests were conducted.

Test example 1

The structural formula prepared in the above Examples 1, 6, 11, 16, 17, or 18 is

The compound 1 is added to a lithium salt, a non-aqueous organic solvent, and a second additive to prepare a lithium secondary battery electrolyte for use in a lithium secondary battery. Wherein, the lithium salt is lithium hexafluorophosphate accounting for 10.0% of the total mass of the electrolyte; the non-aqueous organic solvent is ethylene carbonate, ethyl methyl carbonate, accounting for 87.0% of the total mass of the electrolyte, and the mass ratio is 1:2; The second additive is vinylene carbonate, which accounts for 1.0% of the total mass of the electrolyte; and the compound 1 is added in an amount of 1.0% of the total mass of the electrolyte.

Comparative example 1

A lithium secondary battery electrolyte was prepared in accordance with the above method for use in a lithium secondary battery except that Compound 1 was not added to the lithium secondary battery electrolyte.

Test example 2

The structural formula prepared in the above Example 5, 10 or 15 is

The compound 2 is added to a lithium salt, a non-aqueous organic solvent, and a second additive to prepare a lithium secondary battery electrolyte for use in a lithium secondary battery. Wherein, the lithium salt is lithium hexafluorophosphate which accounts for 15% of the total mass of the electrolyte; the non-aqueous organic solvent is ethylene carbonate, propylene carbonate and diethyl carbonate, accounting for 81.5% of the total mass of the electrolyte, and the mass ratio is 4 :1:5; the second additive is vinylene carbonate, 1,3-propane sultone, respectively accounting for 0.5%, 2.0% of the total mass of the electrolyte; the addition of the compound 2 accounts for the total electrolyte 1.0% of the mass.

Comparative example 2

A lithium secondary battery electrolyte was prepared in accordance with the above method for use in a lithium secondary battery except that Compound 2 was not added to the lithium secondary battery electrolyte.

Test Example 3

The structural formula prepared in the above Examples 2, 7, 12 or 20 is

The compound 3 is added to a lithium salt, a non-aqueous organic solvent, and a second additive to prepare a lithium secondary battery electrolyte for use in a lithium secondary battery. Wherein, the lithium salt is lithium hexafluorophosphate accounting for 10.0% of the total mass of the electrolyte; the non-aqueous organic solvent is a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate, accounting for 83.5% of the total mass of the electrolyte, and the quality The ratio is 3:5:2; the second additive is fluoroethylene carbonate, which accounts for 0.5% of the total mass of the electrolyte; and the compound 3 is added in an amount of 1.0% of the total mass of the electrolyte.

Comparative example 3

Preparing a lithium secondary battery electrolyte according to the above method, for a lithium secondary battery, only in lithium secondary electricity No compound 3 was added to the bath electrolyte.

Test Example 4

The structural formula prepared in the above Example 3, 8, 13 or 19 is

The compound 4 is added to a lithium salt, a non-aqueous organic solvent, and a second additive to prepare a lithium secondary battery electrolyte for use in a lithium secondary battery. Wherein, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide which accounts for 11.5% of the total mass of the electrolyte; the non-aqueous organic solvent is a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate. Accounting for 84.5% of the total mass of the electrolyte, the mass ratio is 3:5:2; the second additive is ethylene carbonate ethylene carbonate, fluoroethylene carbonate, respectively accounting for 0.5% and 1.0% of the total mass of the electrolyte; The amount of the compound 4 added was 1.5% of the total mass of the electrolyte.

Comparative example 4

A lithium secondary battery electrolyte was prepared according to the above method and used for a lithium secondary battery except that the compound 4 was not added to the lithium secondary battery electrolyte.

Test Example 5

The structural formula prepared in the above Example 4, 9 or 14 is

The compound is added to a lithium salt, a non-aqueous organic solvent, and a second additive to prepare a lithium secondary battery electrolyte for use in a lithium secondary battery. Wherein, the lithium salt is lithium hexafluorophosphate accounting for 10.0% of the total mass of the electrolyte; the non-aqueous organic solvent is a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate as a non-aqueous organic solvent, which accounts for the total mass of the electrolyte. 83.5%, the mass ratio is 3:5:2; the second additive is fluoroethylene carbonate, accounting for 3.0% of the total mass of the electrolyte; and the compound 5 is added in an amount of 1.5% of the total mass of the electrolyte.

Comparative example 5

Preparing a lithium secondary battery electrolyte according to the above method, for a lithium secondary battery, only in lithium secondary electricity No compound 5 was added to the bath electrolyte.

Test Example 6

A lithium secondary battery was prepared in accordance with the method of Test Example 5 except that the second additive was not added.

The batteries obtained in all of Test Examples 1 to 5 and all Comparative Examples 1 to 5 described above were subjected to the following experiment:

Cyclic experiment: The batteries obtained in Test Examples 1 to 5 and Comparative Examples 1 to 5 were subjected to a charge and discharge cycle test at a charge and discharge rate of 0.5 C/0.5 C at room temperature of 25 ° C and a high temperature of 55 ° C, respectively, and recorded for the 500th time. The capacity retention rate was obtained by dividing the discharge capacity of the 500th cycle by the first cycle discharge capacity, and the results are shown in Table 1.

High-temperature storage experiment: The batteries of Test Examples 1 to 5 and Comparative Examples 1 to 5 were first charged and discharged at 3.0 to 4.2 V at a charge and discharge rate of 0.5 C/0.5 C at room temperature for 3 times, and then charged to 4.2 V at 0.5 C. , record the thickness of the battery. The battery was placed in an oven at 60 ° C for 15 days, and the thickness of the battery was recorded. The thickness of the second recording battery divided by the thickness of the first recording battery is the battery expansion ratio. The results are recorded as shown in Table 1.

Table 1 Test results of the examples and comparative examples

It can be clearly seen from the above data that the cyclic silicon disulfonate additive has an obvious influence on the capacity retention rate and high temperature cycle of the lithium battery, and the invention adopts the cyclic silicon disulfonate compound as the electrolyte additive, which has outstanding advantages. Mainly manifested in the normal temperature and high temperature cycle capacity retention rate of the battery and the battery expansion rate after high temperature storage. Test Examples 1 to 5 were significantly superior to the comparative examples, and the results of Example 6 showed that the battery also had excellent high temperature, normal temperature cycle performance, and high temperature storage performance without the second additive. Therefore, the battery prepared by using the electrolyte of the present invention can obtain better normal temperature and high temperature cycle performance, and reduce the thickness expansion of the battery during high temperature storage.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. A cyclic silicon disulfonate characterized by comprising the following structural formula:

   

   Wherein R ₁ and R ₂ are the same or different hydrocarbon groups.
2. The cyclic disulfonic acid silyl ester according to claim 1, wherein the hydrocarbon group represented by R ₁ and R ₂ includes a methyl group, an ethyl group, a vinyl group or a phenyl group.
3. A method for preparing a cyclic silicon disulfonate according to claim 1 or 2, comprising the steps of:

   Methylene disulfonic acid or a methylene disulfonate of the formula (I) with a dihydrocarbyl difunctional functional silane of the formula (II), a dihydrocarbyl cyclosiloxane of the formula (III) or a formula The dihydrocarbyl cyclosilazane of (IV) is reacted in a solvent at a certain molar ratio to control the temperature and time of the reaction. After the reaction is completed, the solvent and by-products are separated and removed to obtain the cyclic silicon disulfonate;

   Wherein the structural formula of the methylene disulfonate of the formula (I) is:

   

   The structural formula of the dihydrocarbyl diactive functional group silane of the formula (II) is:

   

   The structural formula of the dihydrocarbyl cyclosiloxane of the formula (III) is:

   

   The structural formula of the dihydrocarbylcyclosilazane of the formula (IV) is:

   

   In the above formula, M is a monovalent metal ion, and Z is a divalent metal ion;

   X, Y are the same or different hydrolyzable reactive functional groups;

   R ₃ is a hydrogen atom, a methyl group, an ethyl group, a propyl group, a phenyl group or an allyl group;

   n is an integer of 3 to 7.
4. The method for preparing a cyclic silicon disulfonate according to claim 3, wherein the monovalent metal ion is an alkali metal ion or a transition metal ion; and the divalent metal ion is an alkaline earth metal ion or a transition a metal ion; the alkali metal ion is a lithium ion, a sodium ion or a potassium ion; the alkaline earth metal ion is a magnesium ion, a calcium ion, a barium ion or a barium ion; and the transition metal ion is a ferrous ion, a zinc ion, or a copper ion Ion or silver ion.
5. The method for preparing a cyclic silicon disulfonate according to claim 3, wherein the easily hydrolyzable reactive functional group is a halogen, an alkoxy group, an acyloxy group, an amide group, an alkenyloxy group, an amine group, A mercapto or hydroxylamine group; wherein the halogen is fluorine, chlorine, bromine or iodine.
6. The method for producing a cyclic silicon disulfonate according to claim 3, wherein the reaction temperature is -20 ° C to 200 ° C and the time is 0.5 to 50 h.
7. The method for preparing a cyclic silicon disulfonate according to claim 3, wherein the methylene disulfonic acid or methylene disulfonate is mixed with a dihydrocarbyl difunctional functional silane and a solvent. The ratio is 1:0.1 to 10:3 to 50.
8. The method for producing a cyclic silicon disulfonate according to claim 3, wherein the methylene disulfonic acid or methylene disulfonate is a dihydrocarbyl cyclosiloxane or a dihydrocarbyl ring Silazane and solvent The molar ratio is 1:0.1 to 5:3 to 50.
9. The method for producing a cyclic silicon disulfonate according to claim 3, 7 or 8, wherein the solvent is an aliphatic hydrocarbon, a halogenated hydrocarbon, an aromatic hydrocarbon, an ether, a ketone, One or two or a combination of two or more kinds of esters, amides, nitriles, and imidazolinones.
10. The method for preparing a cyclic silicon disulfonate according to claim 9, wherein the aliphatic hydrocarbon solvent is n-hexane, cyclohexane or heptane; and the halogenated hydrocarbon solvent is dichloro Methane, dichloroethane or dichloropropane; the aromatic hydrocarbon solvent is toluene, chlorobenzene, fluorobenzene or xylene; the ether solvent is methyl tert-butyl ether, ethylene glycol dimethyl ether, two Oxylanol or dioxane; the ketone solvent is acetone, methyl ethyl ketone, cyclohexanone or methyl isobutyl ketone; the ester solvent is methyl acetate, ethyl acetate, n-propyl acetate, Isopropyl acetate, methyl propionate, ethyl propionate or propyl propionate; the amide solvent is dimethylformamide; the nitrile solvent is acetonitrile; the imidazolinone solvent is dimethyl Imidazolinone.