Silicone ester compound as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of electrolyte additives, and particularly relates to an estersil compound and a preparation method and application thereof. Wherein the general formula of the estersil compound is as shown in formula (I) to formula (IV), R1 is methyl, ethyl, isopropyl, vinyl or phenyl, and R2 is CH2 = CH <->, CH3 <->, CH3CH2 <->, (CH3) 2CH <->, (CH3) 3C <-> or H <->. The estersil compound provided by the invention can be used as an electrolyte additive, and can inhibit discoloration of an electrolyte in an electrochemical device, so that the storage time is prolonged, and the comprehensive performance of the electrochemical device is improved.

Description

Technical Field

[0001] This invention belongs to the field of electrolyte additive technology, specifically relating to a silicon ester compound, its preparation method, and its application. Background Technology

[0002] Compared with other rechargeable batteries, lithium-ion rechargeable batteries have advantages such as high operating voltage, long cycle life, low self-discharge rate, environmental friendliness and no memory effect, and are therefore widely used in various fields such as digital, energy storage, power, aerospace, deep-sea operations, communication and information and emergency rescue.

[0003] Lithium-ion battery electrolyte is one of the main and key materials in lithium-ion secondary batteries, and its quality is crucial to battery performance. Moisture, acidity, and color are among the three most basic indicators for evaluating electrolyte quality. Moisture and related active substances in the electrolyte will eventually transform into acidic substances. The increase in acidity will exacerbate the increase in electrolyte color. Simultaneously, environmental factors such as temperature and light during preparation and storage will also significantly affect the color and acidity of the electrolyte. Therefore, the color, acidity, and moisture of lithium-ion battery electrolytes interact and create a vicious cycle, becoming major obstacles to the stability of lithium-ion battery electrolyte quality, thus affecting the promotion and use of many formulated electrolytes. Therefore, developing a novel electrolyte additive to inhibit the increase of electrolyte color is of great significance. Summary of the Invention

[0004] The technical problem solved by this invention is that the electrolyte of a secondary battery exhibits an increase in color during storage or use.

[0005] To address the aforementioned technical problems, this invention provides a silicon ester compound, its preparation method, and its applications.

[0006] Specifically, in the first aspect, the present invention provides a silicone ester compound with the following general formulas (I)-(IV):

[0007]

[0008] Wherein, R1 is an ethyl group, the silicone ester compound is a silicone propionate compound, and the silicone propionate compound is selected from any one of the following compounds:

[0009] Formula (I): Compound 2a: R1 is CH3CH2-; R2 is CH2=CH-;

[0010] Formula (II): Compound 2g: R1 is CH3CH2-; R2 is CH2=CH-;

[0011] Compound 2j: R1 is CH3CH2-; R2 is (CH3)2CH-;

[0012] Compound 2k: R1 is CH3CH2-; R2 is (CH3)3C-;

[0013] Formula (III): Compound 2p: R1 is CH3CH2-; R2 is (CH3)2CH-;

[0014] Compound 2q: R1 is CH3CH2-; R2 is (CH3)3C-;

[0015] Alternatively, R1 is isopropyl, the silyl ester compound is an isobutyrate silyl ester compound, and the isobutyrate silyl ester compound is selected from any of the following compounds:

[0016] Formula (I): Compound 3a: R1 is (CH3)2CH-; R2 is CH2=CH-;

[0017] Compound 3e: R1 is (CH3)2CH-; R2 is (CH3)3C-;

[0018] Formula (II): Compound 3g: R1 is (CH3)2CH-; R2 is CH2=CH-;

[0019] Compound 3j: R1 is (CH3)2CH-; R2 is (CH3)2CH-;

[0020] Compound 3k: R1 is (CH3)2CH-; R2 is (CH3)3C-;

[0021] Compound 3l: R1 is (CH3)2CH-; R2 is H-;

[0022] Formula (III): Compound 3m: R1 is (CH3)2CH-; R2 is CH2=CH-;

[0023] Compound 3p: R1 is (CH3)2CH-; R2 is (CH3)2CH-;

[0024] Compound 3q: R1 is (CH3)2CH-; R2 is (CH3)3C-;

[0025] Compound 3r: R1 is (CH3)2CH-; R2 is H-;

[0026] Formula (IV): Compound 3s: R1 is (CH3)2CH-;

[0027] Alternatively, R1 is a vinyl group, and the silicone ester compound is an acrylate silicone ester compound selected from any of the following compounds:

[0028] Formula (I): Compound 4a: R1 is CH2=CH-; R2 is CH2=CH-;

[0029] Formula (II): Compound 4g: R1 is CH2=CH-; R2 is CH2=CH-;

[0030] Formula (III): Compound 4p: R1 is CH2=CH-; R2 is (CH3)2CH-;

[0031] Alternatively, R1 is a phenyl group, and the silyl ester compound is a benzoic acid silyl ester compound, wherein the benzoic acid silyl ester compound is selected from any of the following compounds:

[0032] Formula (I): Compound 5a: R1 is C6H5-; R2 is CH2=CH-;

[0033] Compound 5e: R1 is C6H5-; R2 is (CH3)3C-;

[0034] Formula (II): Compound 5g: R1 is C6H5-; R2 is CH2=CH-;

[0035] Compound 5i: R1 is C6H5-; R2 is CH3CH2-;

[0036] Compound 5j: R1 is C6H5-; R2 is (CH3)2CH-;

[0037] Compound 5k: R1 is C6H5-; R2 is (CH3)3C-;

[0038] Formula (III): Compound 5p: R1 is C6H5-; R2 is (CH3)2CH-;

[0039] Compound 5q: R1 is C6H5-; R2 is (CH3)3C-;

[0040] Furthermore, in formula (IV), R1 is only isopropyl; R1 does not include ethyl, vinyl, or phenyl.

[0041] Secondly, the present invention provides a silicone ester-based electrolyte additive or electrolyte color-changing inhibitor, wherein the general formula of the silicone ester compound is shown in formulas (I)-(IV) below:

[0042]

[0043] Wherein, R1 is an ethyl group, the silicone ester compound is a silicone propionate compound, and the silicone propionate compound is selected from any one of the following compounds:

[0044] Formula (I): Compound 2a: R1 is CH3CH2-; R2 is CH2=CH-;

[0045] Formula (II): Compound 2g: R1 is CH3CH2-; R2 is CH2=CH-;

[0046] Compound 2j: R1 is CH3CH2-; R2 is (CH3)2CH-;

[0047] Compound 2k: R1 is CH3CH2-; R2 is (CH3)3C-;

[0048] Formula (III): Compound 2p: R1 is CH3CH2-; R2 is (CH3)2CH-;

[0049] Compound 2q: R1 is CH3CH2-; R2 is (CH3)3C-;

[0050] Alternatively, R1 is isopropyl, the silyl ester compound is an isobutyrate silyl ester compound, and the isobutyrate silyl ester compound is selected from any of the following compounds:

[0051] Formula (I): Compound 3a: R1 is (CH3)2CH-; R2 is CH2=CH-;

[0052] Compound 3e: R1 is (CH3)2CH-; R2 is (CH3)3C-;

[0053] Formula (II): Compound 3g: R1 is (CH3)2CH-; R2 is CH2=CH-;

[0054] Compound 3j: R1 is (CH3)2CH-; R2 is (CH3)2CH-;

[0055] Compound 3k: R1 is (CH3)2CH-; R2 is (CH3)3C-;

[0056] Compound 3l: R1 is (CH3)2CH-; R2 is H-;

[0057] Formula (III): Compound 3m: R1 is (CH3)2CH-; R2 is CH2=CH-;

[0058] Compound 3p: R1 is (CH3)2CH-; R2 is (CH3)2CH-;

[0059] Compound 3q: R1 is (CH3)2CH-; R2 is (CH3)3C-;

[0060] Compound 3r: R1 is (CH3)2CH-; R2 is H-;

[0061] Formula (IV): Compound 3s: R1 is (CH3)2CH-;

[0062] Alternatively, R1 is a vinyl group, and the silicone ester compound is an acrylate silicone ester compound selected from any of the following compounds:

[0063] Formula (I): Compound 4a: R1 is CH2=CH-; R2 is CH2=CH-;

[0064] Formula (II): Compound 4g: R1 is CH2=CH-; R2 is CH2=CH-;

[0065] Formula (III): Compound 4p: R1 is CH2=CH-; R2 is (CH3)2CH-;

[0066] Alternatively, R1 is a phenyl group, and the silyl ester compound is a benzoic acid silyl ester compound, wherein the benzoic acid silyl ester compound is selected from any of the following compounds:

[0067] Formula (I): Compound 5a: R1 is C6H5-; R2 is CH2=CH-;

[0068] Compound 5e: R1 is C6H5-; R2 is (CH3)3C-;

[0069] Formula (II): Compound 5g: R1 is C6H5-; R2 is CH2=CH-;

[0070] Compound 5i: R1 is C6H5-; R2 is CH3CH2-;

[0071] Compound 5j: R1 is C6H5-; R2 is (CH3)2CH-;

[0072] Compound 5k: R1 is C6H5-; R2 is (CH3)3C-;

[0073] Formula (III): Compound 5p: R1 is C6H5-; R2 is (CH3)2CH-;

[0074] Compound 5q: R1 is C6H5-; R2 is (CH3)3C-;

[0075] Furthermore, in formula (IV), R1 is only isopropyl; R1 does not include ethyl, vinyl, or phenyl.

[0076] Thirdly, the present invention provides an application of a silicone ester compound in an electrolyte additive, wherein the general formula of the silicone ester compound is shown in formulas (I)-(IV) below:

[0077]

[0078] In equations (I) to (IV), R1 is selected from C. 1-6 alkyl, C 2-6 alkenyl or C 6-10 Aromatic groups;

[0079] The R2 group is selected from H, substituted or unsubstituted C. 1-6 Alkyl, substituted or unsubstituted C 1-6 alkoxy, substituted or unsubstituted C 2-6 alkenyl, substituted or unsubstituted C 2-6 ether group or C 3-6 A heterocyclic group, wherein the heteroatom in the heterocyclic group is one or more of N, O, S, P and B.

[0080] Preferably, the C 3-6 Heterocyclic groups include cycloazoethyl, epoxyethyl, cyclothioethyl, acridinel, oxadiazinyl, thiamethidinel, acridinel, pyrrolyl, pyrrolinyl, pyrrolyl, pyrazolyl, 2-pyrazolinyl, imidazolyl, pyrazolyl, furanyl, tetrahydrofuranyl, tetrahydrothiophene, thiophene, sulfolane, phosphacenyl, oxazolyl, thiazolyl, piperidinyl, tetrahydropyranyl, tetrahydrothiaranyl, pyridinyl, pyranyl, thiaranyl, dihydropyridinyl, morpholinyl, piperazinyl, pyridazinyl, or pyrazinyl.

[0081] Preferably, in formulas (I) to (IV), the R1 group is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, vinyl, propenyl, isopropenyl, butenyl, isobutylenyl, phenyl, benzyl or styryl.

[0082] More preferably, in formulas (I) to (IV), the R1 group is selected from methyl, ethyl, isopropyl, vinyl, or phenyl.

[0083] More preferably, the phenyl group is a substituted or unsubstituted phenyl group; wherein the substituted phenyl group refers to an alkyl group having 1-4 carbon atoms, an alkenyl group having 1-4 carbon atoms, and / or an alkoxy group having 1-4 carbon atoms.

[0084] Preferably, in formulas (I) to (IV), the R2 group is selected from H, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, vinyl, allyl, isoallyl, allyl, isoallyl, cyclopentadienyl, pentadienyl, ethynyl or pentynyl.

[0085] More preferably, in formulas (I) to (IV), the R2 group is selected from H, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, or vinyl.

[0086] Preferably, R1 is methyl, and in formula (I), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms; in formula (II), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms; in formula (III), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms; and / or, in formula (IV), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms.

[0087] Preferably, R1 is an ethyl group, and in formulas (I) and (IV), R2 is selected from H-, alkyl groups having 1-4 carbon atoms, or alkenyl groups having 1-4 carbon atoms; in formula (II), R2 is selected from H-, alkyl groups having 1-4 carbon atoms, or alkenyl groups having 1-4 carbon atoms; in formula (III), R2 is selected from H-, alkyl groups having 1-4 carbon atoms, or alkenyl groups having 1-4 carbon atoms; and / or, in formula (IV), R2 is selected from H-, alkyl groups having 1-4 carbon atoms, or alkenyl groups having 1-4 carbon atoms.

[0088] Preferably, R1 is isopropyl, and in formula (I), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms; in formula (II), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms; in formula (III), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms; and / or in formula (IV), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms.

[0089] Preferably, R1 is a vinyl group, and in formula (I), R2 is selected from H-, alkyl groups having 1-4 carbon atoms, or alkenyl groups having 1-4 carbon atoms; in formula (II), R2 is selected from H-, alkyl groups having 1-4 carbon atoms, or alkenyl groups having 1-4 carbon atoms; in formula (III), R2 is selected from H-, alkyl groups having 1-4 carbon atoms, or alkenyl groups having 1-4 carbon atoms; in formula (IV), R2 is selected from H-, alkyl groups having 1-4 carbon atoms, or alkenyl groups having 1-4 carbon atoms.

[0090] Preferably, R1 is phenyl, and in formula (I), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms; in formula (II), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms; in formula (III), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms; and / or, in formula (IV), R2 is selected from H-, alkyl with 1-4 carbon atoms, or alkenyl with 1-4 carbon atoms.

[0091] Preferably, in formulas (I)-(IV), R1 is methyl, to obtain a silicone acetate electrolyte additive;

[0092]

[0093]

[0094] Preferably, the silicone acetate electrolyte additive is any one of the following compounds:

[0095] Alternatively, in formulas (I)-(IV), R1 is an ethyl group, yielding a propionic silicate electrolyte additive; preferably, the propionic silicate electrolyte additive is any one of the following compounds:

[0096]

[0097] Alternatively, in formulas (I)-(IV), R1 is isopropyl, yielding isobutyrate silicate electrolyte additives; preferably, the isobutyrate silicate electrolyte additive is any one of the following compounds:

[0098]

[0099] Alternatively, in formulas (I)-(IV), R1 is a vinyl group, yielding an acrylate silicone electrolyte additive; preferably, the acrylate silicone electrolyte additive is any one of the following compounds:

[0100]

[0101]

[0102] Alternatively, in formulas (I)-(IV), R1 is a phenyl group, yielding a benzoic acid silicate electrolyte additive; preferably, the benzoic acid silicate electrolyte additive is any one of the following compounds:

[0103]

[0104]

[0105] Fourthly, the present invention provides a method for preparing silicone ester compounds or silicone ester electrolyte additives as follows:

[0106] Wherein, M is selected from H, Li, Na, K, Rb, Cs, or Fr; X is selected from F, Cl, Br, or I;

[0107] Preferably, the preparation method of formula (I), formula (II), formula (III) or formula (IV) includes the following steps:

[0108] S1. Mix the raw material R1COOM and the silicon reagent, add an organic solvent, and react under the action of a catalyst;

[0109] S2. After the reaction is complete, remove the inorganic salts, concentrate to remove the organic solvent, obtain the concentrated solution, distill to obtain the final product;

[0110] More preferably, in step S1, the molar ratio of raw material R1COOM to silicon reagent is 0.1-10:10-0.1; further preferably, it is 0.1-5:5-0.1; even more preferably, in the preparation method of formula (I), the molar ratio of raw material R1COOM to silicon reagent is 0.5-1.5:1.5-0.5; or, in the preparation method of formula (II), the molar ratio of raw material R1COOM to silicon reagent is 1.5-2.5:1.5-0.5; or, in the preparation method of formula (II), the molar ratio of raw material R1COOM to silicon reagent is 2.5-3.5:1.5-0.5; or, in the preparation method of formula (II), the molar ratio of raw material R1COOM to silicon reagent is 3.5-5.5:1.5-0.5.

[0111] And / or, more preferably, in step S1, the organic solvent includes one or more of toluene, benzene, pentane, n-hexane, n-heptane, tertiary methyl ether, tetrahydrofuran, dichloromethane, acetonitrile, dioxane, and ethyl acetate; even more preferably, the volume ratio of the organic solvent to the molar amount of the raw material R1COOM is 0.1-2:0.5-5, wherein the volume of the organic solvent is in L and the molar amount of the raw material R1COOM is in mol;

[0112] And / or, more preferably, in step S1, the catalyst comprises one or more of 18-crown 6, 12-crown 4, triethylamine, diisopropylamine, and p-dimethylaminopyridine; further preferably, the molar ratio of the catalyst to the raw material R1COOM is 0.001-4:0.1-10; even more preferably, it is 0.001-4:0.1-4; and / or, more preferably, the reaction temperature is 0-120°C; further preferably, the reaction temperature is 30-90°C; even more preferably, the reaction temperature is 55-75°C.

[0113] And / or, more preferably, in step S1, the reaction time is 0.5-168 h; preferably 1-20 h; more preferably 2-15 h.

[0114] Fifthly, the present invention provides the application of the aforementioned silicone ester electrolyte additive or the silicone ester compound prepared by the aforementioned preparation method in electrolyte additives.

[0115] The electrolyte additive is an electrolyte additive used in an electrochemical device; preferably, the electrochemical device is a battery. More preferably, the electrochemical device is a lithium-ion battery or a sodium-ion battery.

[0116] Preferably, the application of the silicone ester electrolyte additive or the silicone ester compound in suppressing electrolyte discoloration in electrochemical devices.

[0117] Preferably, the application of the silicone ester electrolyte additive or silicone ester compound in inhibiting the discoloration of the electrolyte caused by the first component is wherein the first component includes one or more of the following: ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, vinylene carbonate, lithium hexafluorophosphate, ethylene sulfate, 3,4-di(trimethylsiloxy)-1-butene, tri(trimethylsilane) phosphate, tri(trimethylsilane) borate, methanedisulfonate, 1,3-propylsulfonate lactone, vinyl ethylene carbonate, fluoroethylene carbonate, lithium bis(fluorosulfonyl)imide, lithium difluorooxalate borate, and lithium difluorophosphate.

[0118] More preferably, the first component comprises ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, vinylene carbonate, lithium hexafluorophosphate, and any one or more of the following components: ethylene sulfate, 3,4-di(trimethylsiloxy)-1-butene, tri(trimethylsilane) phosphate, tri(trimethylsilane) borate, methanedisulfonate, and 1,3-propylsulfonate lactone.

[0119] Preferably, the silicone ester electrolyte additive or silicone ester compound accounts for 0.01% to 30% of the total mass of the electrolyte.

[0120] Preferably, the silicone ester electrolyte additive or silicone ester compound accounts for 0.01% to 10% of the total mass of the electrolyte;

[0121] More preferably, the silicone ester electrolyte additive or silicone ester compound accounts for 0.01% to 5% of the total mass of the electrolyte;

[0122] More preferably, the silicone ester electrolyte additive or silicone ester compound accounts for 0.01% to 2% of the total mass of the electrolyte;

[0123] Most preferably, the silicone ester electrolyte additive or silicone ester compound accounts for 0.01% to 1% of the total mass of the electrolyte.

[0124] In a sixth aspect, the present invention provides an electrolyte additive composition comprising a first component and the silicone ester compound of claim 1; or the composition comprising the first component and the silicone ester electrolyte additive of any one of claims 2-4 or the silicone ester compound prepared by the preparation method of claim 5; wherein the first component comprises one or more of ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, vinylene carbonate, lithium hexafluorophosphate, ethylene sulfate, 3,4-di(trimethylsiloxy)-1-butene, tri(trimethylsilane) phosphate, tri(trimethylsilane) borate, methanedisulfonate, 1,3-propylsulfonate lactone, vinyl ethylene carbonate, fluoroethylene carbonate, lithium bis(fluorosulfonyl)imide, lithium difluorooxalate borate, and lithium difluorophosphate.

[0125] Preferably, the first component comprises ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, vinylene carbonate, lithium hexafluorophosphate, and any one or more of the following components: ethylene sulfate, 3,4-di(trimethylsiloxy)-1-butene, tri(trimethylsilane) phosphate, tri(trimethylsilane) borate, methanedisulfonate, and 1,3-propylsulfonate lactone.

[0126] Beneficial effects of the present invention

[0127] This invention provides a silicon ester compound that can suppress electrolyte discoloration in electrochemical devices. After adding the silicon ester compound of this invention, the electrolyte color decreased to below 50 APHA after 14 days of storage at high temperature (60°C), significantly improving electrolyte discoloration. Furthermore, the silicon ester compound, as an electrolyte additive, does not affect the electrochemical performance of the battery. Attached Figure Description

[0128] Figure 1 The compound 4d prepared in Example 1 1 H-NMR spectrum.

[0129] Figure 2 The compound prepared in Example 2 for 1 hour 1 H-NMR spectrum.

[0130] Figure 3 The compound 1s prepared in Example 4 1 H-NMR spectrum.

[0131] Figure 4 The compound 3d prepared in Example 5 1 H-NMR spectrum.

[0132] Figure 5 The compound 5d prepared in Example 6 1H-NMR spectrum. Detailed Implementation

[0133] As described above, the purpose of this invention is to provide a silicon ester compound, its preparation method, and its application.

[0134] In this invention, the increase in the color intensity of the electrolyte refers to a change in the color of the electrolyte, i.e., discoloration. There are several possible explanations for this discoloration: Commercially available lithium electrolytes are primarily LiPF6, which is highly sensitive to moisture. LiPF6 releases heat during dissolution in a solvent and may produce substances such as PF5 and POF3, which have catalytic polymerization effects, leading to an increase in the acidity and color intensity of the electrolyte; additives and electrolytes in the electrolyte react with carbonyl groups in the solvent to form molten salts, including those formed from lithium ions, which readily show color in the electrolyte; redox reactions occur in the electrolyte, and some substances undergo structural changes after oxidation, resulting in colored substances and thus color changes in the electrolyte; under light and heat, the electrolyte induces free radical reactions, leading to the formation of new substances and causing discoloration. Although the causes of discoloration are varied, they can all be categorized as follows: water, hydrogen fluoride, or similar active substances in the electrolyte directly or indirectly cause the discoloration. In other words, the inventors believe that water, hydrogen fluoride, or similar active substances are the source of electrolyte discoloration. The electrolyte additive in this invention can consume water, hydrogen fluoride, and similar active substances in the electrolyte, while having no effect on the electrolyte's acid value and no deterioration of the battery.

[0135] In this invention, "C" i～j "" indicates that the number of carbon atoms is an integer from i to j. For example, C 1～6 Alkyl groups refer to alkyl groups containing 1 to 6 carbon atoms (including 1 and 6), C 2-6 The alkenyl group refers to an alkenyl group containing 2 to 6 carbon atoms (including 2 and 6).

[0136] The term "alkyl" refers to the portion of an alkane molecule that is missing a hydrogen atom, and is either a straight-chain alkyl group or a branched alkyl group. For example, the alkyl group includes, but is not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, 2,2-dimethylpropyl, 1-ethylpropyl, 2-methylbutyl, and their various branched isomers.

[0137] The term "alkenyl" refers to the portion of an olefin remaining after removing one hydrogen atom. For example, alkenyl groups include, but are not limited to, vinyl, propenyl, allyl, butenyl, or pentenyl.

[0138] The term "aromatic group" refers to the portion of an aromatic hydrocarbon molecule (referring to most aromatic compounds with a benzene ring basic structure) remaining after one or more hydrogen atoms are removed. For example, the aromatic group includes, but is not limited to, phenyl.

[0139] The term "alkoxy" consists of an alkyl group and an oxygen atom, and is usually represented by RO-. For example, the alkoxy group includes, but is not limited to, methoxy (CH3O-), ethoxy (C2H5O-), propoxy (C3H7O-), butoxy (C4H9O-), or pentoxy (C5H-). 11 O-) etc.

[0140] The term "heterocyclic group" refers to the portion of an organic compound containing a heteroatom (non-carbon atom) on a ring after removing one hydrogen atom. Heterocyclic groups include, but are not limited to, epoxyethyl, furanyl, pyridyl, or thiophene groups.

[0141] The term "substituted" means that any usable connection point in the structure can be replaced by a substituent. The substituent includes, but is not limited to, carboxyl, amino, nitrosyl, alcohol hydroxyl, halogen, or hydrocarbon groups.

[0142] The term "phenyl" refers to substituted or unsubstituted phenyl; wherein substituted phenyl means alkyl, alkenyl and / or alkoxy substituted phenyl with 1-4 carbon atoms.

[0143] The first objective of this invention is to provide a silicone ester-based electrolyte additive, wherein the general formula of the silicone ester-based electrolyte additive is shown in formulas (I) to (IV) below:

[0144]

[0145] In equations (I) to (IV), R1 is selected from C. 1-6 alkyl, C 2-6 alkenyl or C 6-10 Aromatic groups;

[0146] R2, R3, and R4 groups are each independently selected from H, substituted or unsubstituted C1-6 alkyl groups, substituted or unsubstituted C6 alkyl groups, and C6 alkyl groups. 1-6 alkoxy, substituted or unsubstituted C 2-6 alkenyl, substituted or unsubstituted C 2-6 ether group or C 3-6 A heterocyclic group, wherein the heteroatom in the heterocyclic group is N, O, S and / or B.

[0147] In this invention, the mechanism by which the silicate ester electrolyte additive inhibits electrolyte discoloration is as follows:

[0148] 1. Mechanism of action of formula (I)

[0149] Interaction with water:

[0150]

[0151] Reaction with hydrogen fluoride:

[0152]

[0153] 2. Mechanism of action of formula (II)

[0154] Interaction with water:

[0155]

[0156] Reaction with hydrogen fluoride:

[0157]

[0158] 3. Mechanism of action of formula (III)

[0159] Interaction with water:

[0160]

[0161] Reaction with hydrogen fluoride:

[0162]

[0163] 4. Mechanism of action of formula (IV)

[0164] Interaction with water:

[0165]

[0166] Reaction with hydrogen fluoride:

[0167]

[0168] In this invention, by altering the structure of the R2 group and its steric hindrance, the ease with which active substances such as H2O and HF attack Si is adjusted, thereby achieving the beneficial effects of regulating molecular structure stability and increasing or decreasing the release rate of molecular power. The functional groups attached to the R2 group can produce even more beneficial effects on the battery. The R1 group can increase or decrease the group power supply effect, thereby adjusting the ease with which active substances attack Si. More importantly, it can adjust the acidity of the new substances formed after the silicon-oxygen bond breaks, and adjust the acid value of the electrolyte. The functional groups attached to the R1 group can produce even more beneficial effects on the battery.

[0169] The silicon ester compounds of this invention preferentially react with active substances such as H2O and HF, but do not react with the second component (lithium salt or other additives) to avoid decomposition. Furthermore, the acid value of the new substances generated after reacting with substances in the electrolyte does not exceed the standard.

[0170] Unless otherwise stated, all reagents / instruments used in the embodiments and comparative examples of this invention are conventional commercially available products.

[0171] To better understand the technical solution of the present invention, a detailed description is provided below with reference to specific embodiments.

[0172] Examples 1-20

[0173] Table 1 Electrolyte formulations of the embodiments

[0174]

[0175]

[0176]

[0177] In this invention, EC is ethylene carbonate, EMC is methyl ethyl carbonate, DMC is dimethyl carbonate, VC is vinylene carbonate, LiPF6 is lithium hexafluorophosphate, DTD is ethylene sulfate, D-TMS is 3,4-di(trimethylsiloxy)-1-butene, TMSP is tri(trimethylsilane) phosphate, TMSB is tri(trimethylsilane) borate, MMDS is methane disulfonate, and PS is 1,3-propylsulfonate lactone.

[0178] Example 1

[0179] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0180] The preparation of the electrolyte for BASE 1-2 includes the following steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives DTD, VC and compound 4d to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a homogeneous electrolyte.

[0181] The only difference between the preparation steps of BASE 1-1 electrolyte and BASE 1-2 electrolyte is that compound 4d is not added.

[0182] (2) Experiment to suppress the color change of DTD (vinyl sulfate) in electrolyte

[0183] The electrolyte prepared by the method in step (1) was transferred to colorless and transparent reagent bottles and stored at 60°C. The color change of the electrolyte was observed, and its color was tested on day 0, day 2, day 7 and day 14. The color test was conducted according to the People's Republic of China National Standard GB / T 9282.1-2008 "Color of transparent liquids as platinum-cobalt grade - Part 1: Visual method". The color test results are shown in Table 3 below (colorimetric method, unit: APHA).

[0184] In this application, the chromaticity data of Examples 1-20 all adopted the above-described chromaticity testing steps.

[0185] Table 3. Color change data of electrolyte stored at 60℃ for different times.

[0186] Sampling time 0 days 2 days 7 days 14 days BASE 1-1 0～5 10～15 45～50 >200 BASE 1-2 0～5 0～5 10～15 45～50

[0187] Table 3 shows that after storage at 60℃ for 14 days, the color of electrolyte BASE 1-2 obtained by adding compound 4d was 45-50 APHA, while the color of electrolyte BASE 1-1 obtained without adding compound 4d was >200 APHA. This indicates that compound 4d, as an electrolyte additive, can inhibit the increase in color of the electrolyte during storage.

[0188] (3) Pouch Battery Manufacturing Steps

[0189] The electrolyte used is the electrolyte prepared in this embodiment; the positive electrode active material is lithium iron phosphate (LFP), the conductive agent is TEMIGO SP, the binder is French Aquamarine PVDF900, and the mass ratio of lithium iron phosphate, conductive agent and PVDF900 in the positive electrode sheet is 95.8:2:2.2; the positive electrode current collector is carbon-coated aluminum foil; the negative electrode material is BTR artificial graphite S360-L2-H, the conductive agent is TEMIGO SP, the binder is CMC2200 (Daicel) and PAA binder (Shenzhen Yanyi AONE), and the mass ratio of artificial graphite, SP, CMC and PAA binder in the negative electrode sheet is 96.7:1:0.5:1.8; the negative electrode current collector is copper foil; the separator is a polypropylene single-layer separator.

[0190] (4) Capacity retention test

[0191] Step 1: At a temperature of 45℃, charge at a constant current and constant voltage of 0.5C until the limiting voltage of 4.25V is reached, and charging ends when the cutoff current drops to 0.02C; let stand for 5 minutes.

[0192] Step 2: Discharge at a constant current of 1C until the cutoff voltage of 3.0V is reached; let stand for 5 minutes.

[0193] Step 3: The cycle starts from Step 1 and ends at Step 2, with a total of 200 cycles.

[0194] The initial discharge capacity of each battery was recorded as the initial capacity, and the discharge capacity after different number of cycles (50, 100, 150 and 200 cycles) was recorded. The capacity retention rate after cycling was calculated based on the discharge capacity after different number of cycles and the initial capacity. The average calculation results of the initial capacity and the capacity retention rate after different number of cycles (50, 100, 150 and 200 cycles) of each battery group are shown in Table 4.

[0195] In this application, Examples 1-20 all adopt the above-described pouch cell preparation steps and capacity retention rate testing methods.

[0196] Table 4. Capacity retention data of pouch cells after cycling at 45℃

[0197] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 1-1 99.0％ 95.5％ 88.8％ 78.6％ BASE 1-2 99.3％ 94.9％ 89.0％ 79.1％

[0198] Conclusion: The capacity retention rate of the pouch cell using BASE 1-1 electrolyte after 200 cycles at 45°C was 78.6%, while the capacity retention rate of the pouch cell using BASE 1-2 electrolyte prepared after adding the compound for 4 days was 79.1% after 200 cycles at 45°C.

[0199] (5) Preparation of compound 4d

[0200]

[0201] 110 g (1.0 mol) of potassium acrylate, 193 g (1.0 mol) of triisopropylchlorosilane, and 500 mL of tetrahydrofuran were added to a container, followed by 3.0 g of 18-crown-6. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 12 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The potassium chloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 4d, with a mass of 205.6 g and a yield of 90.0%. GC analysis showed a purity of 99.6%.

[0202] Compound 4d 1 H-NMR such as Figure 1 As shown, 1 HNMR(400MHz,CDCl3),δ1.054-1.135(d,18H),δ

[0203] 1.288-1.400(m,3H),5.823-5.853(d,1H),6.085-6.153(m,1H),6.349-6.397(d,1H).

[0204] Example 2

[0205] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0206] BASE 2-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives D-TMS, VC and compound 1h to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0℃. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0207] The only difference between the preparation steps of BASE 2-1 electrolyte and BASE 2-2 electrolyte is that no compound 1h is added.

[0208] (2) Experiment on inhibiting the color change of D-TMS (3,4-di(trimethylsiloxy)-1-butene) in electrolyte

[0209] Table 5. Color change data of electrolyte stored at 60℃ for different times.

[0210] Sampling time 0 days 2 days 7 days 14 days BASE 2-1 0～5 15～20 50～100 >200 BASE 2-2 0～5 10～15 20～25 50～100

[0211] Table 5 shows that after storage at 60℃ for 14 days, the electrolyte BASE 2-2 with added compound 1h had a color intensity of 50–100 APHA, while the electrolyte BASE 2-1 without added compound 1h had a color intensity >200 APHA. This indicates that compound 1h, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0212] Table 6. Capacity retention data of pouch cells after cycling at 45℃

[0213] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 2-1 98.9％ 94.7％ 87.8％ 78.7％ BASE 2-2 99.1％ 94.8％ 88.7％ 78.2％

[0214] As shown in Table 6, the capacity retention rate of the pouch cell using electrolyte BASE 2-1 after 200 cycles at 45°C was 78.7%, while the capacity retention rate of the pouch cell using electrolyte BASE 2-2 prepared by adding the compound for 1 hour was 78.2% after 200 cycles at 45°C.

[0215] (5) Preparation of compound 1h

[0216]

[0217] 120 g (2.0 mol) of acetic acid, 129.1 g (1.0 mol) of dimethyldichlorosilane, and 500 mL of tetrahydrofuran were added to a container. Then, 253.0 g (2.5 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 1 h, with a mass of 142.9 g and a yield of 81.0%. GC analysis showed a purity of 99.3%.

[0218] Compound 1h 1 H-NMR such as Figure 2 As shown, 1 HNMR (400MHz, CDCl3), δ0.495-0.549 (s, 6H), δ

[0219] 2.073-2.090 (s, 6H).

[0220] Example 3

[0221] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0222] BASE 3-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives TMSP, VC and compound 5m to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0223] The only difference between the preparation steps of BASE 3-1 electrolyte and BASE 3-2 electrolyte is that compound 5m is not added.

[0224] (2) Experiment on inhibiting the color change of TMSP (tris(trimethylsilane)phosphate) in electrolyte

[0225] Table 7. Color change data of electrolyte stored at 60℃ for different times.

[0226] Sampling time 0 days 2 days 7 days 14 days BASE 3-1 0～5 10～15 40～45 >200 BASE 3-2 0～5 0～5 15～20 45～50

[0227] Table 7 shows that after 14 days of storage at 60℃, the electrolyte BASE 3-2 with added compound 5m had a color intensity of 45–50 APHA, while the electrolyte BASE 3-1 without added compound 5m had a color intensity >200 APHA. This indicates that compound 5m, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0228] Table 8. Capacity retention data of pouch cells after cycling at 45℃

[0229] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 3-1 97.0％ 93.8％ 85.9％ 76.6％ BASE 3-2 98.4％ 92.6％ 84.4％ 76.9％

[0230] As shown in Table 8, the capacity retention rate of the pouch cell with electrolyte BASE 3-1 after 200 cycles at 45°C was 76.6%, while the capacity retention rate of the pouch cell with electrolyte BASE 3-2 prepared by adding compound 5m was 76.9% after 200 cycles at 45°C.

[0231] (5) Preparation of compound 5m

[0232]

[0233] Add 366.4 g (3.0 mol) of benzoic acid, 161.5 g (1.0 mol) of vinyltrichlorosilane, and 800 mL of tetrahydrofuran to a container. Then add 354.2 g (3.5 mol) of triethylamine, an organic base. Purge the mixture three times with nitrogen, stir thoroughly, and heat to 65 °C. React for 5 hours. Take a sample for GC analysis. After the reaction is complete, stop heating, cool to room temperature, filter to remove triethylamine hydrochloride, wash the filter cake with a small amount of tetrahydrofuran, combine the filtrates, and concentrate under vacuum in a water bath at 45 °C until no tetrahydrofuran remains, obtaining a concentrated solution. Distill the concentrated solution, remove the foremilk, and collect the main fraction to obtain the target compound 5m, with a mass of 344.2 g, yield 82.2%. GC analysis shows a purity of 99.6%.

[0234] Compound 5m 1 HNMR(400MHz, CDCl3),0.611-0.654(d,1H),0.785-0.793(m,1H),1.149-1.1 57(d,1H), δ7.498-7.573(m,6H),7.680-7.721(m,3H),8.126-8.199(m,6H).

[0235] Example 4

[0236] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0237] BASE 4-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives TMSB, VC and compound 1s to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0238] The only difference between the preparation steps of BASE 4-1 electrolyte and BASE 4-2 electrolyte is that compound 1s is not added.

[0239] (2) Experiment on inhibiting the color change of TMSB (tris(trimethylsilane)borate) in electrolyte

[0240] Table 9. Color change data of electrolyte stored at 60℃ for different times.

[0241] Sampling time 0 days 2 days 7 days 14 days BASE 4-1 0～5 15～20 45～50 >200 BASE 4-2 0～5 10～15 15～20 40～45

[0242] Table 9 shows that after storage at 60℃ for 14 days, the electrolyte BASE 4-2 with added compound 1s had a color intensity of 40–45 APHA, while the electrolyte BASE 4-1 without added compound 1s had a color intensity >200 APHA. This indicates that compound 1s, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0243] Table 10. Capacity retention data of pouch cells after cycling at 45℃

[0244] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 4-1 98.7％ 94.7％ 87.1％ 77.7％ BASE 4-2 99.1％ 94.3％ 86.8％ 77.1％

[0245] As shown in Table 10, the capacity retention rate of the pouch cell using electrolyte BASE 4-1 after 200 cycles at 45°C is 77.7%, while the capacity retention rate of the pouch cell using electrolyte BASE 4-2 prepared by adding the compound 1 second after 200 cycles at 45°C is 77.1%.

[0246] (5) Preparation of compound 1s

[0247]

[0248] Add 392.56 g (4.0 mol) of potassium acetate, 170.0 g (1.0 mol) of tetrachlorosilane, and 1450 mL of tetrahydrofuran to a container, followed by 10.7 g of 18-crown-6. Purge the mixture three times with nitrogen, stir thoroughly, and then heat to 65 °C for 12 hours. Perform GC analysis on a sample. After the reaction is complete, stop heating, cool to room temperature, filter to remove potassium chloride, wash the filter cake with a small amount of tetrahydrofuran, combine the filtrates, and concentrate under vacuum in a 45 °C water bath until no tetrahydrofuran remains, obtaining a concentrated solution. Distill the concentrated solution, remove the foremilk fraction, and collect the main fraction to obtain the target compound 1s, with a mass of 215.4 g and a yield of 81.5%. GC analysis showed a purity of 99.3%.

[0249] Compound 1s 1 H-NMR such as Figure 3 As shown, 1 HNMR (400MHz, CDCl3), 2.099-2.187 (s, 12H).

[0250] Example 5

[0251] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0252] BASE 5-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives MMDS, VC and compound 3d to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0253] The only difference between the preparation steps of BASE 5-1 electrolyte and BASE 5-2 electrolyte is that compound 3d is not added.

[0254] (2) Experiment on inhibiting the color change of MMDS (methylene methane disulfonate) in electrolyte

[0255] Table 11. Color change data of electrolyte stored at 60℃ for different times.

[0256] Sampling time 0 days 2 days 7 days 14 days BASE 5-1 0～5 10～15 40～45 >200 BASE 5-2 0～5 5～10 15～20 45～50

[0257] Table 11 shows that after storage at 60℃ for 14 days, the electrolyte BASE 5-2 with added compound 3d had a color intensity of 45–50 APHA, while the electrolyte BASE 5-1 without added compound 3d had a color intensity >200 APHA. This indicates that compound 3d, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0258] Table 12 Capacity retention data of pouch cells after cycling at 45℃

[0259]

[0260]

[0261] As shown in Table 12, the capacity retention rate of the pouch cell using electrolyte BASE 5-1 after 200 cycles at 45°C was 76.8%, while the capacity retention rate of the pouch cell using electrolyte BASE 5-2, prepared after adding the compound for 3 days, after 200 cycles at 45°C was 77.0%.

[0262] (5) Preparation of compound 3d

[0263]

[0264] 126.2 g (1.0 mol) of potassium isobutyrate, 192.8 g (1.0 mol) of triisopropylchlorosilane, and 500 mL of tetrahydrofuran were added to a container. Then, 3.7 g (0.014 mol) of 18-crown-6 was added. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 12 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The potassium chloride salt was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 3d, with a mass of 221.3 g and a yield of 90.5%. GC analysis showed a purity of 99.9%.

[0265] 3d compounds 1 H-NMR such as Figure 4 As shown, 1 HNMR(400MHz,CDCl3),δ1.037-1.087(d,18H),δ

[0266] 1.163-1.193(m,6H),1.249-1.351(m,3H),2.528-2.597(m,1H).

[0267] Example 6

[0268] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0269] BASE 6-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives PS, VC and compound 5d to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0270] The only difference between the preparation steps of BASE 6-1 electrolyte and BASE 6-2 electrolyte is that compound 5d is not added.

[0271] (2) Experiment on inhibiting the color change of PS (1,3-propylsulfonyl lactone) in electrolyte

[0272] Table 13. Color change data of electrolyte stored at 60℃ for different times.

[0273] Sampling time 0 days 2 days 7 days 14 days BASE 6-1 0～5 10～15 50～100 >200 BASE 6-2 0～5 0～5 15～20 40～45

[0274] Table 13 shows that after storage at 60℃ for 14 days, the electrolyte BASE 6-2 with added compound 5d had a color intensity of 40–45 APHA, while the electrolyte BASE 6-1 without added compound 5d had a color intensity >200 APHA. This indicates that compound 5d, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0275] Table 14. Capacity retention data of pouch cells after cycling at 45℃

[0276] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 6-1 98.0％ 93.3％ 85.9％ 77.0％ BASE 6-2 98.1％ 92.9％ 86.0％ 77.2％

[0277] As shown in Table 14, the capacity retention rate of the pouch cell using electrolyte BASE 6-1 after battery cycling at 45°C was 77.0%, while the capacity retention rate of the pouch cell using electrolyte BASE 6-2 prepared after adding the compound for 5 days was 77.2% after battery cycling at 45°C for 14 days.

[0278] (5) Preparation of compound 5d

[0279]

[0280] 122.1 g (1.0 mol) of benzoic acid, 192.8 g (1.0 mol) of triisopropylchlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 121.4 g (1.2 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 5d, with a mass of 253.1 g and a yield of 90.9%. GC analysis showed a purity of 99.8%.

[0281] Compound 5d 1 H-NMR such as Figure 5 As shown, 1 HNMR(400MHz,CDCl3),δ1.054-1.161(d,18H),δ

[0282] 1.378-1.490(m,3H), δ7.424-7.537(m,2H), 7.540-7.577(m,1H), 8.065-8.086(m,2H).

[0283] Example 7

[0284] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0285] BASE 7-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives DTD, VC and compound 3c to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0286] The only difference between the preparation steps of BASE 7-1 electrolyte and BASE 7-2 electrolyte is that compound 3c is not added.

[0287] (2) Experiment on inhibiting the color change of DTD in electrolyte

[0288] Table 15. Color change data of electrolyte stored at 60℃ for different times.

[0289]

[0290]

[0291] Table 15 shows that after storage at 60℃ for 14 days, the color of electrolyte BASE 7-2 with added compound 3c was 45-50 APHA, while the color of electrolyte BASE 7-1 without added compound 3c was >200 APHA. This indicates that compound 3c, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0292] Table 16 Capacity retention data of pouch cells after cycling at 45℃

[0293] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 7-1 99.2％ 95.0％ 88.3％ 78.9％ BASE 7-2 99.5％ 95.3％ 89.2％ 81.4％

[0294] As shown in Table 16, the capacity retention rate of the pouch cell filled with electrolyte BASE 7-1 was 78.9% after 200 cycles at 45°C, while the capacity retention rate of the pouch cell filled with electrolyte BASE 7-2 prepared with compound 3c was 81.4% after 200 cycles at 45°C.

[0295] (5) Preparation of compound 3c

[0296]

[0297] Add 88.1 g (1.0 mol) of isobutyric acid, 150.8 g (1.0 mol) of triethylchlorosilane, and 400 mL of tetrahydrofuran to a container. Then add 121.7 g (1.2 mol) of triethylamine, an organic base. Purge the mixture with nitrogen three times, stir thoroughly, and heat to 65 °C. React for 5 hours. Take a sample for GC analysis. After the reaction is complete, stop heating, cool to room temperature, filter to remove triethylamine hydrochloride, wash the filter cake with a small amount of tetrahydrofuran, combine the filtrates, and concentrate under vacuum in a water bath at 45 °C until no tetrahydrofuran remains. Distill the concentrate, remove the foremilk, and collect the main fraction to obtain the target compound 3c, with a mass of 180.0 g and a yield of 88.8%. Perform GC analysis; purity 99.0%, GC-MS: 202.4.

[0298] Example 8

[0299] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0300] BASE 8-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives D-TMS, VC and compound 2a to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0301] The only difference between the preparation steps of BASE 8-1 electrolyte and BASE 8-2 electrolyte is that compound 2a is not added.

[0302] (2) Inhibition D-TMS Color change experiment in electrolyte

[0303] Table 17. Color change data of electrolyte stored at 60℃ for different times.

[0304] Sampling time 0 days 2 days 7 days 14 days BASE 8-1 0～5 10～15 35～40 >200 BASE 8-2 0～5 5～10 15～20 45～50

[0305] Table 17 shows that after storage at 60℃ for 14 days, the electrolyte BASE 8-2 with added compound 2a had a color intensity of 45–50 APHA, while the electrolyte BASE 8-1 without added compound 2a had a color intensity >200 APHA. This indicates that compound 2a, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0306] Table 18 Capacity retention data of pouch cells after cycling at 45℃

[0307] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 8-1 99.0％ 94.6％ 87.0％ 79.9％ BASE 8-2 99.7％ 95.9％ 90.3％ 84.1％

[0308] As shown in Table 18, the capacity retention rate of the pouch cell using electrolyte BASE 8-1 after 200 cycles at 45°C is 79.9%, while the capacity retention rate of the pouch cell using electrolyte BASE 8-2 prepared with compound 2a is 84.1% after 200 cycles at 45°C.

[0309] (5) Preparation of compound 2a

[0310]

[0311] 74.0 g (1.0 mol) of propionic acid, 144.8 g (1.0 mol) of trivinylchlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 121.4 g (1.2 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 2a, with a mass of 158.1 g and a yield of 86.7%. GC analysis showed a purity of 99.6% (GC-MS: 182.3).

[0312] Example 9

[0313] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0314] BASE 9-2 Electrolyte Preparation Steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives TMSP, VC and 4g of compound to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0315] The only difference between the preparation steps of BASE 9-1 electrolyte and BASE 9-2 electrolyte is that 4g of compound is not added.

[0316] (2) Experiment on inhibiting the discoloration of TMSP in electrolyte

[0317] Table 19. Color change data of electrolyte stored at 60℃ for different times.

[0318] Sampling time 0 days 2 days 7 days 14 days BASE 9-1 0～5 5～10 25～30 >200 BASE 9-2 0～5 5～10 15～20 35～40

[0319] Table 19 shows that after storage at 60℃ for 14 days, the electrolyte BASE 9-2 with 4g of compound added had a color intensity of 35-40 APHA, while the electrolyte BASE 9-1 without 4g of compound added had a color intensity >200 APHA. This indicates that compound 4g, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0320] Table 20: Capacity retention data of pouch cells after cycling at 45℃

[0321] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 9-1 99.0％ 92.3％ 83.0％ 74.7％ BASE 9-2 99.1％ 94.7％ 88.8％ 80.6％

[0322] As shown in Table 20, the capacity retention rate of the pouch cell using electrolyte BASE 9-1 after 200 cycles at 45°C was 74.7%, while the capacity retention rate of the pouch cell using electrolyte BASE 9-2 (prepared with 4g of compound) after 200 cycles at 45°C was 80.6%.

[0323] (5) Prepare 4g of compound

[0324]

[0325] Add 72.1 g (1.0 mol) of acrylic acid, 76.5 g (0.5 mol) of divinyldichlorosilane, and 400 mL of tetrahydrofuran to a container, followed by 121.4 g (1.2 mol) of triethylamine. Purge the mixture three times with nitrogen, stir thoroughly, and then heat to 65 °C for 5 hours. Perform GC analysis on a sample. After the reaction is complete, stop heating, cool to room temperature, filter to remove triethylamine hydrochloride, wash the filter cake with a small amount of tetrahydrofuran, combine the filtrates, and concentrate under vacuum in a 45 °C water bath until no tetrahydrofuran remains, obtaining a concentrated solution. Distill the concentrated solution, remove the foremilk, and collect the main fraction to obtain 4 g of the target compound (99.0 g, yield 88.3%). GC analysis showed a purity of 99.4% (GC-MS: 224.3).

[0326] Example 10

[0327] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0328] BASE 10-2 Electrolyte Preparation Steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives TMSB, VC and compound 3j to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a homogeneous electrolyte.

[0329] The only difference between the preparation steps of BASE 10-1 electrolyte and BASE 10-2 electrolyte is that compound 3j is not added.

[0330] (2) Experiment on inhibiting the discoloration of TMSB in electrolyte

[0331] Table 21. Color change data of electrolyte stored at 60℃ for different times.

[0332] Sampling time 0 days 2 days 7 days 14 days BASE 10-1 0～5 5～10 20～25 40～45 BASE 10-2 0～5 5～10 15～20 25～30

[0333] Table 21 shows that after storage at 60℃ for 14 days, the electrolyte BASE 10-2 with added compound 3j had a color intensity of 25–30 APHA, while the electrolyte BASE 10-1 without added compound 3j had a color intensity of 40–45 APHA. This indicates that compound 3j, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0334] Table 22 Capacity retention data of pouch cells after cycling at 45℃

[0335] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 10-1 99.8％ 93.3％ 87.4％ 79.9％ BASE 10-2 99.8％ 95.0％ 91.3％ 83.5％

[0336] As shown in Table 22, the capacity retention rate of the pouch cell using electrolyte BASE 10-1 after 200 cycles at 45°C is 79.9%, while the capacity retention rate of the pouch cell using electrolyte BASE 10-2 prepared with compound 3j is 83.5% after 200 cycles at 45°C.

[0337] (5) Preparation of compound 3j

[0338]

[0339] Add 88.1 g (1.0 mol) of isobutyric acid, 92.5 g (0.5 mol) of diisopropyldichlorosilane, and 400 mL of tetrahydrofuran to a container. Then add 122.1 g (1.2 mol) of triethylamine, an organic base. Purge the mixture with nitrogen three times, stir thoroughly, and heat to 65 °C for 5 hours. Take a sample for GC analysis. After the reaction is complete, stop heating, cool to room temperature, filter to remove triethylamine hydrochloride, wash the filter cake with a small amount of tetrahydrofuran, combine the filtrates, and concentrate under vacuum in a water bath at 45 °C until no tetrahydrofuran remains, obtaining a concentrated solution. Distill the concentrated solution, remove the foremilk, and collect the main fraction to obtain the target compound 3j, with a mass of 130.0 g and a yield of 90.0%. Perform GC analysis; the purity is 99.3%, GC-MS: 288.5.

[0340] Example 11

[0341] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0342] BASE 11-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives MMDS, VC and compound 3k to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0343] The only difference between the preparation steps of BASE 11-1 electrolyte and BASE 11-2 electrolyte is that compound 3k is not added.

[0344] (2) Experiment on inhibiting the color change of MMDS in electrolyte

[0345] Table 23. Color change data of electrolyte stored at 60℃ for different times.

[0346] Sampling time 0 days 2 days 7 days 14 days BASE 11-1 0～5 10～15 35～40 >200 BASE 11-2 0～5 5～10 15～20 45～50

[0347] Table 23 shows that after storage at 60℃ for 14 days, the electrolyte BASE 11-2 with added compound 3k had a color intensity of 45–50 APHA, while the electrolyte BASE 11-1 without added compound 3k had a color intensity >200 APHA. This indicates that compound 3k, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0348] Table 24 Capacity retention data of pouch cells after cycling at 45℃

[0349] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 11-1 99.7％ 94.0％ 88.0％ 80.2％ BASE 11-2 99.9％ 95.3％ 90.3％ 83.1％

[0350] As shown in Table 24, the capacity retention rate of the pouch cell using electrolyte BASE 11-1 after 200 cycles at 45°C is 80.2%, while the capacity retention rate of the pouch cell using electrolyte BASE 11-2 prepared with the addition of compound 3k is 83.1% after 200 cycles at 45°C.

[0351] (5) Preparation of compound 3k

[0352]

[0353] 88.0 g (1.0 mol) of isobutyric acid, 106.6 g (0.5 mol) of di-tert-butyldichlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 121.4 g (1.2 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 3K, with a mass of 130.6 g and a yield of 82.5%. GC analysis showed a purity of 99.3% (GC-MS: 316.6).

[0354] Example 12

[0355] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0356] BASE 12-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives PS, VC and compound 4p to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0357] The only difference between the preparation steps of BASE 12-1 electrolyte and BASE 12-2 electrolyte is that compound 4p is not added.

[0358] (2) Experiment on inhibiting the discoloration of PS in electrolyte

[0359] Table 25. Color change data of electrolyte stored at 60℃ for different times.

[0360] Sampling time 0 days 2 days 7 days 14 days BASE 12-1 0～5 10～15 35～40 >200 BASE 12-2 0～5 5～10 15～20 45～50

[0361] Table 25 shows that after storage at 60℃ for 14 days, the electrolyte BASE 12-2 with added compound 4p had a color intensity of 45–50 APHA, while the electrolyte BASE 12-1 without added compound 4p had a color intensity >200 APHA. This indicates that compound 4p, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0362] Table 26 Capacity retention data of pouch cells after cycling at 45℃

[0363] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 12-1 99.2％ 93.0％ 87.4％ 76.7％ BASE 12-2 99.8％ 94.1％ 90.0％ 82.8％

[0364] As shown in Table 26, the capacity retention rate of the pouch cell using electrolyte BASE 12-1 after 200 cycles at 45°C is 76.7%, while the capacity retention rate of the pouch cell using electrolyte BASE 12-2 prepared with compound 4p after 200 cycles at 45°C is 82.8%.

[0365] (5) Preparation of compound 4p

[0366]

[0367] 72.1 g (1.0 mol) of acrylic acid, 59.2 g (0.33 mol) of isopropyltrichlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 121.4 g (1.2 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 4p, with a mass of 73.9 g and a yield of 78.0%. GC analysis showed a purity of 99.0% (GC-MS: 284.3).

[0368] Example 13

[0369] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0370] BASE 13-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives DTD, VC and compound 2q to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0371] The only difference between the preparation steps of BASE 13-1 electrolyte and BASE 13-2 electrolyte is that compound 2q is not added.

[0372] (2) Experiment on inhibiting the color change of DTD in electrolyte

[0373] Table 27. Color change data of electrolyte stored at 60℃ for different times.

[0374] Sampling time 0 days 2 days 7 days 14 days BASE 13-1 0～5 10～15 40～45 >200 BASE 13-2 0～5 5～10 15～20 40～45

[0375] Table 27 shows that after storage at 60℃ for 14 days, the electrolyte BASE 13-2 with added compound 2q had a color intensity of 40–45 APHA, while the electrolyte BASE 13-1 without added compound 2q had a color intensity >200 APHA. This indicates that compound 2q, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0376] Table 28 Capacity retention data of pouch cells after cycling at 45℃

[0377] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 13-1 99.8％ 94.7％ 88.0％ 79.9％ BASE 13-2 99.7％ 95.1％ 89.3％ 80.1％

[0378] As shown in Table 28, the capacity retention rate of the pouch cell using electrolyte BASE 13-1 after 200 cycles at 45°C is 79.9%, while the capacity retention rate of the pouch cell using electrolyte BASE 13-2 prepared with compound 2q is 80.1% after 200 cycles at 45°C.

[0379] (5) Preparation of compound 2q

[0380]

[0381] 222.24 g (3.0 mol) of propionic acid, 191.6 g (1.0 mol) of tert-butyltrichlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 121.3 g (1.2 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 2q, with a mass of 273.7 g and a yield of 89.9%. GC analysis showed a purity of 99.0% (GC-MS: 304.4).

[0382] Example 14

[0383] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0384] BASE 14-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives D-TMS, VC and compound 5a to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a homogeneous electrolyte.

[0385] The only difference between the preparation steps of BASE 14-1 electrolyte and BASE 14-2 electrolyte is that compound 5a is not added.

[0386] (2) Experiment on inhibiting the discoloration of D-TMS in electrolyte

[0387] Table 29. Color change data of electrolyte stored at 60℃ for different times.

[0388] Sampling time 0 days 2 days 7 days 14 days BASE 14-1 0～5 5～10 30～35 >200 BASE 14-2 0～5 5～10 15～20 35～40

[0389] Table 29 shows that after storage at 60℃ for 14 days, the electrolyte BASE 14-2 with added compound 5a had a color intensity of 35–40 APHA, while the electrolyte BASE 14-1 without added compound 5a had a color intensity >200 APHA. This indicates that compound 5a, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0390] Table 30 Capacity retention data of pouch cells after cycling at 45℃

[0391] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 14-1 98.5％ 92.6％ 84.7％ 76.8％ BASE 14-2 98.9％ 92.9％ 85.5％ 77.0％

[0392] As shown in Table 30, the capacity retention rate of the pouch cell using electrolyte BASE 14-1 after 200 cycles at 45°C is 76.8%, while the capacity retention rate of the pouch cell using electrolyte BASE 14-2 prepared with compound 5a is 77.0% after 200 cycles at 45°C.

[0393] (5) Preparation of compound 5a

[0394]

[0395] 122.5 g (1.0 mol) of benzoic acid, 145.8 g (1.0 mol) of trivinylchlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 122.5 g (1.2 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 5a, with a mass of 186.6 g and a yield of 81.0%. GC analysis showed a purity of 99.5% (GC-MS: 230.3).

[0396] Example 15

[0397] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0398] BASE 15-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives TMSP, VC and compound 5i to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0399] The only difference between the preparation steps of BASE 15-1 electrolyte and BASE 15-2 electrolyte is that compound 5i is not added.

[0400] (2) Experiment on inhibiting the discoloration of TMSP in electrolyte

[0401] Table 31. Color change data of electrolyte stored at 60℃ for different times.

[0402] Sampling time 0 days 2 days 7 days 14 days BASE 15-1 0～5 5～10 35～40 >200 BASE 15-2 0～5 5～10 20～25 40～45

[0403] Table 31 shows that after storage at 60℃ for 14 days, the electrolyte BASE 15-2 with added compound 5i had a color intensity of 40–45 APHA, while the electrolyte BASE 15-1 without added compound 5i had a color intensity >200 APHA. This indicates that compound 5i, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0404] Table 32 Capacity retention data of pouch cells after cycling at 45℃

[0405] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 15-1 99.9％ 95.0％ 89.0％ 80.8％ BASE 15-2 99.9％ 95.3％ 89.7％ 89.2％

[0406] As shown in Table 32, the capacity retention rate of the pouch cell using electrolyte BASE 15-1 after 200 cycles at 45°C is 80.8%, while the capacity retention rate of the pouch cell using electrolyte BASE 15-2 prepared with the addition of compound 5i is 89.2% after 200 cycles at 45°C.

[0407] (5) Preparation of compound 5i

[0408]

[0409] 122.0 g (1.0 mol) of benzoic acid, 78.7 g (0.5 mol) of diethyldichlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 121.3 g (1.2 mol) of triethylamine was added. The mixture was purged with nitrogen three times, stirred thoroughly, and heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 5i, with a mass of 134.7 g and a yield of 82.0%. GC analysis showed a purity of 99.5% (GC-MS: 328.4).

[0410] Example 16

[0411] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0412] BASE 16-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives TMSB, VC and 5g of compound to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0413] The only difference between the preparation steps of BASE 16-1 electrolyte and BASE 16-2 electrolyte is that no 5g of compound is added.

[0414] (2) Experiment on inhibiting the discoloration of TMSB in electrolyte

[0415] Table 33. Color change data of electrolyte stored at 60℃ for different times.

[0416] Sampling time 0 days 2 days 7 days 14 days BASE 16-1 0～5 5～10 20～25 45～50 BASE 16-2 0～5 0～5 10～15 20～25

[0417] Table 33 shows that after storage at 60℃ for 14 days, the electrolyte BASE 16-2 with 5g of compound added had a color of 20-25 APHA, while the electrolyte BASE 16-1 without 5g of compound added had a color of 45-50 APHA. This indicates that 5g of compound, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0418] Table 34 Capacity retention data of pouch cells after cycling at 45℃

[0419]

[0420]

[0421] As shown in Table 34, the capacity retention rate of the pouch cell using electrolyte BASE 16-1 after 200 cycles at 45°C is 80.0%, while the capacity retention rate of the pouch cell using electrolyte BASE 16-2 (prepared with 5g of compound) after 200 cycles at 45°C is 79.8%.

[0422] (5) Prepare 5g of compound

[0423]

[0424] 123.0 g (1.0 mol) of benzoic acid, 76.5 g (0.5 mol) of divinyldichlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 122.3 g (1.2 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain 5 g of the target compound (118.9 g, yield 73.3%). GC analysis showed a purity of 99.7% (GC-MS: 324.4).

[0425] Example 17

[0426] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0427] BASE 17-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives MMDS, VC and compound 5j to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0428] The only difference between the preparation steps of BASE 17-1 electrolyte and BASE 17-2 electrolyte is that compound 5j is not added.

[0429] (2) Experiment on inhibiting the color change of MMDS in electrolyte

[0430] Table 35. Color change data of electrolyte stored at 60℃ for different times.

[0431] Sampling time 0 days 2 days 7 days 14 days BASE 17-1 0～5 10～15 40～55 >200 BASE 17-2 0～5 5～10 20～25 40～45

[0432] Table 35 shows that after storage at 60℃ for 14 days, the electrolyte BASE 17-2 with added compound 5j had a color intensity of 40–45 APHA, while the electrolyte BASE 17-1 without added compound 5j had a color intensity >200 APHA. This indicates that compound 5j, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0433] Table 36. Capacity retention data of pouch cells after cycling at 45°C.

[0434] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 17-1 99.5％ 95.8％ 88.3％ 80.2％ BASE 17-2 99.8％ 96.1％ 88.8％ 80.2％

[0435] As shown in Table 36, the capacity retention rate of the pouch cell using electrolyte BASE 17-1 after 200 cycles at 45°C is 80.2%, while the capacity retention rate of the pouch cell using electrolyte BASE 17-2 prepared with compound 5j after 200 cycles at 45°C is 80.2%.

[0436] (5) Preparation of compound 5j

[0437]

[0438] 122.4 g (1.0 mol) of benzoic acid, 92.5 g (0.5 mol) of diisopropyldichlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 120.0 g (1.2 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 5j, with a mass of 141.7 g and a yield of 79.5%. GC analysis showed a purity of 99.2% (GC-MS: 356.5).

[0439] Example 18

[0440] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0441] BASE 18-2 Electrolyte Preparation Procedure: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives PS, VC and compound 5k to the mixture. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake to dissolve it and form a homogeneous electrolyte.

[0442] The only difference between the preparation steps of BASE 18-1 electrolyte and BASE 18-2 electrolyte is that compound 5k is not added.

[0443] (2) Experiment on inhibiting the discoloration of PS in electrolyte

[0444] Table 37. Color change data of electrolyte stored at 60℃ for different times.

[0445] Sampling time 0 days 2 days 7 days 14 days BASE 18-1 0～5 5～10 30～35 >200 BASE 18-2 0～5 5～10 15～20 40～45

[0446] Table 37 shows that after storage at 60℃ for 14 days, the electrolyte BASE 18-2 with added compound 5k had a color intensity of 40–45 APHA, while the electrolyte BASE 18-1 without added compound 5k had a color intensity >200 APHA. This indicates that compound 5k, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0447] Table 38 Capacity retention data of pouch cells after cycling at 45°C

[0448] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 18-1 99.0％ 93.1％ 86.3％ 77.7％ BASE 18-2 99.6％ 94.7％ 87.4％ 78.0％

[0449] As shown in Table 38, the capacity retention rate of the pouch cell using electrolyte BASE 18-1 after 200 cycles at 45°C is 77.7%, while the capacity retention rate of the pouch cell using electrolyte BASE 18-2 prepared with the addition of compound 5k is 78.0% after 200 cycles at 45°C.

[0450] (5) Preparation of compound 5k

[0451]

[0452] 122.2 g (1.0 mol) of benzoic acid, 106.6 g (0.5 mol) of di-tert-butyldichlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 111.3 g (1.1 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 5K, with a mass of 165.4 g and a yield of 86.0%. GC analysis showed a purity of 99.5% (GC-MS: 384.4).

[0453] Example 19

[0454] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0455] BASE 19-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives PS, VC and compound 5p to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a homogeneous electrolyte.

[0456] The only difference between the preparation steps of BASE 19-1 electrolyte and BASE 19-2 electrolyte is that compound 5p is not added.

[0457] (2) Experiment on inhibiting the discoloration of PS in electrolyte

[0458] Table 39. Color change data of electrolyte stored at 60℃ for different times.

[0459]

[0460]

[0461] As shown in Table 39, after storage at 60℃ for 14 days, the electrolyte BASE 19-2 with added compound 5p had a color intensity of 35–40 APHA, while the electrolyte BASE 19-1 without added compound 5p had a color intensity >200 APHA. This indicates that compound 5p, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0462] Table 40: Capacity retention data of pouch cells after cycling at 45°C.

[0463] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 19-1 99.8％ 94.7％ 88.0％ 79.5％ BASE 19-2 99.7％ 95.1％ 89.3％ 80.1％

[0464] As shown in Table 40, the capacity retention rate of the pouch cell using electrolyte BASE 19-1 after 200 cycles at 45°C is 79.5%, while the capacity retention rate of the pouch cell using electrolyte BASE 19-2 prepared with the addition of compound 5p is 80.1% after 200 cycles at 45°C.

[0465] (5) Preparation of compound 5p

[0466]

[0467] 122.0 g (1.0 mol) of benzoic acid, 59.2 g (0.3 mol) of isopropyltrichlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 120.8 g (1.2 mol) of triethylamine was added. The mixture was purged with nitrogen three times, stirred thoroughly, and heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 5p, with a mass of 117.3 g and a yield of 81.0%. GC analysis showed a purity of 99.3% (GC-MS: 434.5).

[0468] Example 20

[0469] (1) Preparation of electrolyte. The electrolyte formula is shown in Table 1.

[0470] BASE 20-2 Electrolyte preparation steps: First, prepare a non-aqueous mixed solvent of EC, EMC and DMC in an Ar atmosphere glove box. Then, add electrolyte additives PS, VC and compound 5q to it. Next, place the mixed solution in a refrigerator in the glove box to cool to 0°C. Slowly add the electrolyte lithium salt LiPF6 and gently shake it to dissolve it and form a uniform electrolyte.

[0471] The only difference between the preparation steps of BASE 20-1 electrolyte and BASE 20-2 electrolyte is that compound 5q is not added.

[0472] (2) Experiment on inhibiting the discoloration of PS in electrolyte

[0473] Table 41. Color change data of electrolyte stored at 60℃ for different times.

[0474] Sampling time 0 days 2 days 7 days 14 days BASE 20-1 0～5 5～10 25～30 >200 BASE 20-2 0～5 5～10 15～20 35～40

[0475] Table 41 shows that after storage at 60℃ for 14 days, the electrolyte BASE 20-2 with added compound 5q had a color intensity of 35–40 APHA, while the electrolyte BASE 20-1 without added compound 5q had a color intensity >200 APHA. This indicates that compound 5q, as an electrolyte additive, can inhibit discoloration of the electrolyte during storage.

[0476] Table 42 Capacity retention data of pouch cells after cycling at 45℃

[0477] Cycle number 50 weeks 100 weeks 150 weeks 200 weeks BASE 20-1 99.5％ 94.8％ 87.7％ 79.0％ BASE 20-2 99.6％ 94.7％ 88.8％ 80.3％

[0478] As shown in Table 42, the capacity retention rate of the pouch cell using electrolyte BASE 20-1 after 200 cycles at 45°C is 79.0%, while the capacity retention rate of the pouch cell using electrolyte BASE 20-2 prepared with compound 5q is 80.3% after 200 cycles at 45°C.

[0479] (5) Preparation of compound 5q

[0480]

[0481] 122.1 g (1.0 mol) of benzoic acid, 63.8 g (0.3 mol) of tert-butyltrichlorosilane, and 400 mL of tetrahydrofuran were added to a container. Then, 120.0 g (1.2 mol) of triethylamine was added as an organic base. The mixture was purged with nitrogen three times, stirred thoroughly, and then heated to 65 °C for 5 hours. A sample was taken for GC analysis. After the reaction was complete, heating was stopped, and the mixture was cooled to room temperature. The triethylamine hydrochloride was removed by filtration, and the filter cake was washed with a small amount of tetrahydrofuran. The filtrates were combined and concentrated under vacuum in a water bath at 45 °C until no tetrahydrofuran remained, yielding a concentrated solution. The concentrated solution was distilled, the foremilk was removed, and the main fraction was collected to obtain the target compound 5q, with a mass of 120.0 g and a yield of 80.0%. GC analysis showed a purity of 99.0% (GC-MS: 448.6).

[0482] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Based on the technical solutions of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A silicone ester-based electrolyte additive, characterized in that, The silicone ester electrolyte additive is a silicone ester compound with the following general formulas (I)-(IV): and / or Wherein, R1 is an ethyl group, the silicone ester compound is a silicone propionate compound, and the silicone propionate compound is selected from any one of the following compounds: Formula (I): Compound 2a: R1 is CH3CH2-; R2 is CH2=CH-; Equation (II): Compound 2g: R1 is CH3CH2-; R2 is CH2=CH-; Compound 2j: R1 is CH3CH2-; R2 is (CH3)2CH-; Compound 2k: R1 is CH3CH2-; R2 is (CH3)3C-; Equation (III): Compound 2p: R1 is CH3CH2-; R2 is (CH3)2CH-; Compound 2q: R1 is CH3CH2-; R2 is (CH3)3C-; Alternatively, R1 is isopropyl, the silyl ester compound is an isobutyrate silyl ester compound, and the isobutyrate silyl ester compound is selected from any of the following compounds: Formula (I): Compound 3a: R1 is (CH3)2CH-; R2 is CH2=CH-; Compound 3e: R1 is (CH3)2CH-; R2 is (CH3)3C-; Equation (II): Compound 3g: R1 is (CH3)2CH-; R2 is CH2=CH-; Compound 3j: R1 is (CH3)2CH-; R2 is (CH3)2CH-; Compound 3k: R1 is (CH3)2CH-; R2 is (CH3)3C-; Compound 3l: R1 is (CH3)2CH-; R2 is H-; Equation (III): Compound 3m: R1 is (CH3)2CH-; R2 is CH2=CH-; Compound 3p: R1 is (CH3)2CH-; R2 is (CH3)2CH-; Compound 3q: R1 is (CH3)2CH-; R2 is (CH3)3C-; Compound 3r: R1 is (CH3)2CH-; R2 is H-; Formula (IV): Compound 3s: R1 is (CH3)2CH-; Alternatively, R1 is a vinyl group, and the silicone ester compound is an acrylate silicone ester compound selected from any of the following compounds: Formula (I): Compound 4a: R1 is CH2=CH-; R2 is CH2=CH-; Equation (II): Compound 4g: R1 is CH2=CH-; R2 is CH2=CH-; Equation (III): Compound 4p: R1 is CH2=CH-; R2 is (CH3)2CH-; Alternatively, R1 is a phenyl group, and the silyl ester compound is a benzoic acid silyl ester compound, wherein the benzoic acid silyl ester compound is selected from any of the following compounds: Formula (I): Compound 5a: R1 is C6H5-; R2 is CH2=CH-; Compound 5e: R1 is C6H5-; R2 is (CH3)3C-; Equation (II): Compound 5g: R1 is C6H5-; R2 is CH2=CH-; Compound 5i: R1 is C6H5-; R2 is CH3CH2-; Compound 5j: R1 is C6H5-; R2 is (CH3)2CH-; Compound 5k: R1 is C6H5-; R2 is (CH3)3C-; Equation (III): Compound 5p: R1 is C6H5-; R2 is (CH3)2CH-; Compound 5q: R1 is C6H5-; R2 is (CH3)3C-; Furthermore, in formula (IV), R1 is only isopropyl; R1 does not include ethyl, vinyl, or phenyl.

2. The application of a silicone ester compound in an electrolyte additive, characterized in that, The general formulas of the silane compounds are shown in formulas (I) to (IV) below: and / or In equations (I) to (IV), R1 is selected from C. 1-6 alkyl, C 2-6 alkenyl or C 6-10 Aromatic groups; The R2 group is selected from H, substituted or unsubstituted C. 1-6 Alkyl, substituted or unsubstituted C 1-6 alkoxy, substituted or unsubstituted C 2-6 alkenyl, substituted or unsubstituted C 2-6 ether group or C 3-6 A heterocyclic group, wherein the heteroatom in the heterocyclic group is one or more of N, O, S, P and B.

3. The application according to claim 2, wherein, In formulas (I)-(IV), the R1 group is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, vinyl, propenyl, isopropenyl, butenyl, isobutylenyl, phenyl, benzyl, or styryl; preferably, the R1 group is selected from methyl, ethyl, isopropyl, vinyl, or phenyl; more preferably, the phenyl is a substituted or unsubstituted phenyl; wherein the substituted phenyl refers to an alkyl group having 1-4 carbon atoms, an alkenyl group having 1-4 carbon atoms, and / or an alkoxy-substituted phenyl group having 1-4 carbon atoms; And / or, in formulas (I) to (IV), the R2 group is selected from H-, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, vinyl, allyl, isoallyl, allyl, isoallyl, cyclopentadienyl, pentadienyl, ethynyl or pentynyl; preferably, the R2 group is selected from H-, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl or vinyl; Preferably, R1 is methyl, and in formulas (I), (II), (III), or (IV), R2 is selected from H-, alkyl, or alkenyl with 1-4 carbon atoms; and / or, R1 is ethyl, and in formulas (I), (II), (III), or (IV), R2 is selected from H-, alkyl, or alkenyl with 1-4 carbon atoms; and / or, R1 is isopropyl, and in formulas (I), (II), (III), or (IV) In formula (I), (II), (III) or (IV), R2 is selected from H-, alkyl or alkenyl with 1-4 carbon atoms; and / or, R1 is vinyl, and in formula (I), (II), (III) or (IV), R2 is selected from H-, alkyl or alkenyl with 1-4 carbon atoms; and / or, R1 is phenyl, and in formula (I), (II), (III) or (IV), R2 is selected from H-, alkyl or alkenyl with 1-4 carbon atoms.

4. The application according to claim 2 or 3, wherein, In formulas (I)-(IV), R1 is methyl, and the obtained silicone ester electrolyte additive is a silicone acetate electrolyte additive; Preferably, the silicone acetate electrolyte additive is any one of the following compounds: Formula (I): Compound 1a: R1 is CH3-; R2 is CH2=CH-; Compound 1b: R1 is CH3-; R2 is CH3-; Compound 1c: R1 is CH3-; R2 is CH3CH2-; Compound 1d: R1 is CH3-; R2 is (CH3)2CH-; Compound 1e: R1 is CH3-; R2 is (CH3)3C-; Compound 1f: R1 is CH3-; R2 is H-; Equation (II): Compound 1g: R1 is CH3-; R2 is CH2=CH-; Compound 1h: R1 is CH3-; R2 is CH3-; Compound 1i: R1 is CH3-; R2 is CH3CH2-; Compound 1j: R1 is CH3-; R2 is (CH3)2CH-; Compound 1k: R1 is CH3-; R2 is (CH3)3C-; Compound 1l: R1 is CH3-; R2 is H-; Equation (III): Compound 1m: R1 is CH3-; R2 is CH2=CH-; Compound 1n: R1 is CH3-; R2 is CH3-; Compound 1o: R1 is CH3-; R2 is CH3CH2-; Compound 1p: R1 is CH3-; R2 is (CH3)2CH-; Compound 1q: R1 is CH3-; R2 is (CH3)3C-; Compound 1r: R1 is CH3-; R2 is H-; Formula (IV): Compound 1s: R1 is CH3-; Alternatively, in formulas (I) to (IV), R1 is ethyl, and the obtained silicone ester electrolyte additive is a propionic silicone ester electrolyte additive; Preferably, the propionic silicone electrolyte additive is any one of the following compounds: Formula (I): Compound 2a: R1 is CH3CH2-; R2 is CH2=CH-; Compound 2b: R1 is CH3CH2-; R2 is CH3-; Compound 2c: R1 is CH3CH2-; R2 is CH3CH2-; Compound 2d: R1 is CH3CH2-; R2 is (CH3)2CH-; Compound 2e: R1 is CH3CH2-; R2 is (CH3)3C-; Compound 2f: R1 is CH3CH2-; R2 is H-; Equation (II): Compound 2g: R1 is CH3CH2-; R2 is CH2=CH-; Compound 2h: R1 is CH3CH2-; R2 is CH3-; Compound 2i: R1 is CH3CH2-; R2 is CH3CH2-; Compound 2j: R1 is CH3CH2-; R2 is (CH3)2CH-; Compound 2k: R1 is CH3CH2-; R2 is (CH3)3C-; Compound 2l: R1 is CH3CH2-; R2 is H-; Equation (III): Compound 2m: R1 is CH3CH2-; R2 is CH2=CH- Compound 2n: R1 is CH3CH2-; R2 is CH3-; Compound 2o: R1 is CH3CH2-; R2 is CH3CH2-; Compound 2p: R1 is CH3CH2-; R2 is (CH3)2CH-; Compound 2q: R1 is CH3CH2-; R2 is (CH3)3C-; Compound 2r: R1 is CH3CH2-; R2 is H-; Formula (IV): Compound 2s: R1 is CH3CH2-; Alternatively, in formulas (I) to (IV), R1 is isopropyl, and the resulting silicone ester electrolyte additive is isobutyrate silicone ester electrolyte additive; Preferably, the isobutyrate silicate electrolyte additive is any one of the following compounds: Formula (I): Compound 3a: R1 is (CH3)2CH-; R2 is CH2=CH-; Compound 3b: R1 is (CH3)2CH-; R2 is CH3-; Compound 3c: R1 is (CH3)2CH-; R2 is CH3CH2-; Compound 3d: R1 is (CH3)2CH-; R2 is (CH3)2CH-; Compound 3e: R1 is (CH3)2CH-; R2 is (CH3)3C-; Compound 3f: R1 is (CH3)2CH-; R2 is H-; Equation (II): Compound 3g: R1 is (CH3)2CH-; R2 is CH2=CH-; Compound 3h: R1 is (CH3)2CH-; R2 is CH3-; Compound 3i: R1 is (CH3)2CH-; R2 is CH3CH2-; Compound 3j: R1 is (CH3)2CH-; R2 is (CH3)2CH-; Compound 3k: R1 is (CH3)2CH-; R2 is (CH3)3C-; Compound 3l: R1 is (CH3)2CH-; R2 is H-; Equation (III): Compound 3m: R1 is (CH3)2CH-; R2 is CH2=CH-; Compound 3n: R1 is (CH3)2CH-; R2 is CH3-; Compound 3o: R1 is (CH3)2CH-; R2 is CH3CH2-; Compound 3p: R1 is (CH3)2CH-; R2 is (CH3)2CH-; Compound 3q: R1 is (CH3)2CH-; R2 is (CH3)3C-; Compound 3r: R1 is (CH3)2CH-; R2 is H-; Formula (IV): Compound 3s: R1 is (CH3)2CH-; Alternatively, in formulas (I) to (IV), R1 is a vinyl group, and the resulting silicone ester electrolyte additive is an acrylic silicone ester electrolyte additive. Preferably, the acrylate silicone electrolyte additive is any one of the following compounds: Formula (I): Compound 4a: R1 is CH2=CH-; R2 is CH2=CH-; Compound 4b: R1 is CH2=CH-; R2 is CH3-; Compound 4c: R1 is CH2=CH-; R2 is CH3CH2-; Compound 4d: R1 is CH2=CH-; R2 is (CH3)2CH-; Compound 4e: R1 is CH2=CH-; R2 is (CH3)3C-; Compound 4f: R1 is CH2=CH-; R2 is H-; Equation (II): Compound 4g: R1 is CH2=CH-; R2 is CH2=CH-; Compound 4h: R1 is CH2=CH-; R2 is CH3-; Compound 4i: R1 is CH2=CH-; R2 is CH3CH2-; Compound 4j: R1 is CH2=CH-; R2 is (CH3)2CH-; Compound 4k: R1 is CH2=CH-; R2 is (CH3)3C-; Compound 4l: R1 is CH2=CH-; R2 is H-; Equation (III): Compound 4m: R1 is CH2=CH-; R2 is CH2=CH-; Compound 4n: R1 is CH2=CH-; R2 is CH3-; Compound 4o: R1 is CH2=CH-; R2 is CH3CH2-; Compound 4p: R1 is CH2=CH-; R2 is (CH3)2CH-; Compound 4q: R1 is CH2=CH-; R2 is (CH3)3C-; Compound 4r: R1 is CH2=CH-; R2 is H-; Formula (IV): Compound 4s: R1 is CH2=CH-; Alternatively, in formulas (I) to (IV), R1 is phenyl, and the resulting silicone ester electrolyte additive is a benzoic acid silicone ester electrolyte additive; Preferably, the benzoic acid silicone electrolyte additive is any one of the following compounds: Formula (I): Compound 5a: R1 is C6H5-; R2 is CH2=CH-; Compound 5b: R1 is C6H5-; R2 is CH3-; Compound 5c: R1 is C6H5-; R2 is CH3CH2-; Compound 5d: R1 is C6H5-; R2 is (CH3)2CH-; Compound 5e: R1 is C6H5-; R2 is (CH3)3C-; Compound 5f: R1 is C6H5-; R2 is H-; Equation (II): Compound 5g: R1 is C6H5-; R2 is CH2=CH-; Compound 5h: R1 is C6H5-; R2 is CH3-; Compound 5i: R1 is C6H5-; R2 is CH3CH2-; Compound 5j: R1 is C6H5-; R2 is (CH3)2CH-; Compound 5k: R1 is C6H5-; R2 is (CH3)3C-; Compound 5l: R1 is C6H5-; R2 is H-; Equation (III): Compound 5m: R1 is C6H5-; R2 is CH2=CH-; Compound 5n: R1 is C6H5-; R2 is CH3-; Compound 5o: R1 is C6H5-; R2 is CH3CH2-; Compound 5p: R1 is C6H5-; R2 is (CH3)2CH-; Compound 5q: R1 is C6H5-; R2 is (CH3)3C-; Compound 5r: R1 is C6H5-; R2 is H-; Formula (IV): Compound 5s: R1 is C6H5-.

5. A method for preparing the silicone ester electrolyte additive according to claim 1, characterized in that, The synthetic routes for formulas (I), (II), (III), or (IV) are as follows: Synthesis route of formula (I): Synthesis route of formula (II): Synthetic route of formula (III): Alternatively, the synthetic route of formula (IV): In the synthetic routes of formula (I), formula (II), formula (III) or formula (IV), M is selected from H, Li, Na, K, Rb, Cs or Fr; X is selected from F, Cl, Br or I; Preferably, the preparation method of formula (I), formula (II), formula (III) or formula (IV) includes the following steps: S1. Mix the raw material R1COOM and the silicon reagent, add an organic solvent, and react under the action of a catalyst; S2. After the reaction is complete, remove the inorganic salts, concentrate to remove the organic solvent, obtain the concentrated solution, distill to obtain the final product; More preferably, in step S1, the molar ratio of raw material R1COOM to silicon reagent is 0.1-10:10-0.1; even more preferably, the molar ratio of raw material R1COOM to silicon reagent is 0.1-5:5-0.1; And / or, more preferably, in step S1, the organic solvent includes one or more of toluene, benzene, pentane, n-hexane, n-heptane, tertiary methyl ether, tetrahydrofuran, dichloromethane, acetonitrile, dioxane, and ethyl acetate; even more preferably, the volume ratio of the organic solvent to the molar amount of the raw material R1COOM is 0.1-2:0.5-5, wherein the volume of the organic solvent is in L and the molar amount of the raw material R1COOM is in mol; And / or, more preferably, in step S1, the catalyst comprises one or more of 18-crown 6, 12-crown 4, triethylamine, diisopropylamine, and p-dimethylaminopyridine; further preferably, the molar ratio of the catalyst to the raw material R1COOM is 0.001-4:0.1-10; even more preferably, the molar ratio of the catalyst to the raw material R1COOM is 0.001-4:0.1-4; and / or, more preferably, the reaction temperature is 0-120°C; further preferably, the reaction temperature is 30-90°C; even more preferably, the reaction temperature is 55-75°C.

6. The application of the silicone ester electrolyte additive of claim 1 or the silicone ester electrolyte additive prepared by the preparation method of claim 5 in electrolyte additives.

7. The application according to any one of claims 2-4 or the application according to claim 6, wherein, The electrolyte additive is an electrolyte additive used in an electrochemical device; preferably, the electrochemical device is a lithium-ion battery or a sodium-ion battery. More preferably, the application of the silicone ester electrolyte additive or the silicone ester compound in suppressing electrolyte discoloration in electrochemical devices; More preferably, the application of the silicone ester electrolyte additive or silicone ester compound in suppressing electrolyte discoloration caused by the first component includes one or more of the following: ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, vinylene carbonate, lithium hexafluorophosphate, vinyl sulfate, 3,4-di(trimethylsiloxy)-1-butene, tris(trimethylsilane)phosphate, tris(trimethylsilane)borate, methanedisulfonate, 1,3-propylsulfonate lactone, vinyl ethylene carbonate, fluoroethylene carbonate, lithium bis(fluorosulfonyl)imide, lithium difluorooxalate borate, and lithium difluorophosphate; wherein the silicone ester electrolyte additive or silicone ester compound serves as a second component in the electrolyte. More preferably, the first component comprises ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, vinylene carbonate, lithium hexafluorophosphate, and any one or more of the following components: ethylene sulfate, 3,4-di(trimethylsiloxy)-1-butene, tri(trimethylsilane) phosphate, tri(trimethylsilane) borate, methanedisulfonate, and 1,3-propylsulfonate lactone.

8. The application according to claim 6 or 7, wherein, The silicone ester electrolyte additive or silicone ester compound accounts for 0.01% to 30% of the total mass of the electrolyte; Preferably, the silicone ester electrolyte additive or silicone ester compound accounts for 0.01% to 10% of the total mass of the electrolyte; More preferably, the silicone ester electrolyte additive or silicone ester compound accounts for 0.01% to 5% of the total mass of the electrolyte; More preferably, the silicone ester electrolyte additive or silicone ester compound accounts for 0.01% to 2% of the total mass of the electrolyte; Most preferably, the silicone ester electrolyte additive or silicone ester compound accounts for 0.01% to 1% of the total mass of the electrolyte.

9. An electrolyte additive composition, characterized in that, The composition comprises a first component and a second component; The first component comprises one or more of the following: ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, vinylene carbonate, lithium hexafluorophosphate, ethylene sulfate, 3,4-di(trimethylsiloxy)-1-butene, tris(trimethylsilane) phosphate, tris(trimethylsilane) borate, methanedisulfonate, 1,3-propylsulfonate lactone, vinyl ethylene carbonate, fluoroethylene carbonate, lithium bis(fluorosulfonyl)imide, lithium difluorooxalate borate, and lithium difluorophosphate; preferably, the first component comprises ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, vinylene carbonate, lithium hexafluorophosphate, and any one or more of the following components: ethylene sulfate, 3,4-di(trimethylsiloxy)-1-butene, tris(trimethylsilane) phosphate, tris(trimethylsilane) borate, methanedisulfonate, and 1,3-propylsulfonate lactone. The second component includes the silicone ester electrolyte additive of claim 1, the silicone ester electrolyte additive prepared by the preparation method of claim 5, or the silicone ester compound in the application of any one of claims 2-4 in electrolyte additives.

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