JP2022517285A - Electrolytes and electrochemical devices - Google Patents

Abstract

The present application relates to an electrolytic solution and an electrochemical device and an electronic device containing the electrolytic solution. The electrolytic solution contains a fluoroethylene carbonate and a silicate compound, and optionally further contains at least one of a cyclic carboxylic acid anhydride compound and a disulfonic acid ester compound. The electrolytic solution optionally further contains at least one of unsaturated cyclic carbonate, cyclic sultone, cyclic sulfate lactone and a nitrile compound as other additives. The electrolytic solution of the present invention can significantly improve the cycle life and rate discharge performance of the battery. [Selection diagram] None

Description

[Priority claim]
This application claims the priority of the Chinese application of application number CN20091327801.8 filed on 20 December 2019, the contents of which are incorporated in the text with reference to the full text.

The present application relates to the technical field of energy storage, and particularly to an electrolytic solution, an electrochemical device containing the electrolytic solution, and an electronic device including the electrochemical device.

Lithium-ion batteries are next-generation environment-friendly batteries developed in the 90s of the last century, and have the advantages of high operating voltage, high specific energy, long cycle life, environmental friendliness, and no memory effect. It has a wide range of applications in fields such as new energy electric vehicles, information / communication / home appliances (3C) products, portable electronic devices, electric tools, energy storage, military, and aerospace. However, with the development of applications of lithium-ion batteries and the sustainable development of modern information technology, higher demands are placed on the battery energy density and safety of lithium-ion batteries.

The development of high-voltage lithium-ion batteries is one of the effective means for increasing the energy density of lithium-ion batteries. Under high voltage and high temperature conditions, the oxidative activity of the positive electrode material is high, the stability is lowered, the oxidative decomposition of the conventional electrolytic solution on the positive electrode surface is accelerated, and gas is generated. At the same time, the transition metal elements (for example, nickel, cobalt, manganese, etc.) in the positive electrode active material (particularly manganese-based materials) elute faster and are deposited on the negative electrode through the charge / discharge process, thereby forming a solid electrolyte membrane (SEI). Is destroyed and the electrolytic solution is reduced and decomposed at the negative electrode, which further deteriorates the electrochemical performance of the lithium ion battery. How to further improve the high temperature storage and cycle performance of lithium-ion batteries has already become an urgent issue to be solved in this field.

The present application provides an electrolytic solution, an electrochemical device containing the electrolytic solution, and an electronic device including the electrochemical device, and the electrolytic solution contains a fluoroethylene carbonate and a silicate compound. The addition of a specific proportion of fluoroethylene carbonate and silicate compound to the electrolyte is advantageous for the formation of a stable interface protection layer on the surface of the positive and negative electrodes, which significantly improves the cycle life and high temperature storage performance of the lithium ion battery. Will be done.

In some embodiments, the present application provides an electrolytic solution containing a fluoroethylene carbonate and a silicate compound.

In some examples, the structure of the silicate compound in the electrolyte is set forth in Formula I.

式中、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４はそれぞれ、置換又は無置換のＣ_１～Ｃ_１０炭化水素基から独立して選択され、置換の場合、置換基はハロゲンであり、前記シリケート化合物と前記フルオロエチレンカーボネートとの質量比は、１：１～１：１０である。

In the formula, R ₁ , R ₂ , R ₃ and R ₄ are selected independently of the substituted or unsubstituted C ₁ to C ₁₀ hydrocarbon groups, respectively, and in the case of substitution, the substituent is a halogen and the silicate is described above. The mass ratio of the compound to the fluoroethylene carbonate is 1: 1 to 1:10.

In some examples, the silicate compound in the electrolytic solution comprises at least one of the following:

In some embodiments, the content of the silicate compound in the electrolytic solution is from about 0.1% by weight to about 5% by weight of the total weight of the electrolytic solution.

In some embodiments, the electrolyte further comprises a cyclic carboxylic acid anhydride compound comprising at least one of a formula II, formula III or formula IV structure.

式中、Ｒ_５、Ｒ_６、Ｒ_７、Ｒ_８、Ｒ_９、Ｒ_１０及びＲ_１１はそれぞれ、水素、ハロゲン及び置換又は無置換のＣ_１～Ｃ_１０炭化水素基から独立して選択され、置換の場合、置換基は、ハロゲンである。

In the formula, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ and R ₁₁ are selected independently of hydrogen, halogen and substituted or unsubstituted C ₁ to C ₁₀ hydrocarbon groups, respectively. In the case of substitution, the substituent is a halogen.

In some embodiments, the content of the cyclic carboxylic acid anhydride in the electrolytic solution is from about 0.1% by weight to about 5% by weight of the total weight of the electrolytic solution.

In some embodiments, in the electrolyte, the cyclic carboxylic acid anhydride is maleic acid anhydride, succinic acid anhydride, 2-methylsuccinic acid anhydride, 2,3-dimethylsuccinic acid anhydride or glutaric acid. Contains at least one of the anhydrides.

In some embodiments, the electrolytic solution further comprises a disulfonic acid ester compound having the formula V.

式中、ｎは１～４の整数である。

In the formula, n is an integer of 1 to 4.

In some examples, the content of the disulfonic acid ester compound in the electrolytic solution is about 0.1% by weight to about 5% by weight of the total weight of the electrolytic solution.

In some examples, the disulfonic acid ester compound is selected from methylenemethane disulfonate.

In some examples, the electrolyte further comprises at least one of LiPO ₂ F ₂ , unsaturated cyclic carbonate, cyclic sultone, cyclic sulfate lactone or nitrile compound as an additive. The content of the additive is about 0.001% by weight to about 13% by weight of the total weight of the electrolytic solution.
The content of the LiPO ₂ F ₂ is about 0.001% by weight to about 2% by weight of the total weight of the electrolytic solution.
The unsaturated cyclic carbonate contains at least one of vinylene carbonate and vinylethylene carbonate, and the content of the unsaturated cyclic carbonate is about 0.001% by weight to about 2% by weight of the total weight of the electrolytic solution. By weight%
The annular sultone contains at least one of 1,3-propane sultone, 1,4-butane sultone or 1,3-propene sultone, and the content of the annular sultone is about 0 of the total weight of the electrolytic solution. It ranges from 0.01% by weight to about 3% by weight.
The cyclic sulfate lactone contains at least one of ethylene sulfate, propylene sulfate or 4-methylethylene sulfate, and the content of the cyclic sulfate lactone is 0.01% by weight to 3% by weight of the total weight of the electrolytic solution. %, And the nitrile compound is succinonitrile, glutaronitrile, adiponitrile, 2-methyleneglutaronitrile, dipropylmarononitrile, 1,3,6-hexanetricarbonitrile, 1,2,6-hexane. It contains at least one of tricarbonitrile, 1,3,5-pentanetricarbonitrile or 1,2-bis (2-cyanoethoxy) ethane, and the content of the nitrile compound is the total weight of the electrolytic solution. It is about 0.5% by weight to about 7% by weight.

In some embodiments, the present application provides an electrochemical device comprising any one of the above electrolytes.

In some embodiments, the present application provides electronic devices including the electrochemical devices described above.

Additional embodiments and advantages of the present application will be partially described and shown in subsequent discussions, or will be described by implementing embodiments of the present application.

Hereinafter, embodiments of the present application will be described in detail. The embodiments of the present application should not be construed as limiting the present application.

As used herein, the terms "abbreviation," "generally," "substantially," and "about" are used to describe and describe small changes. When used in combination with an event or condition, the term can refer to an example in which the event or condition occurs exactly and an example in which the event or condition occurs very closely. For example, when used in combination with a numerical value, the term is ± 10% or less of the numerical value, for example ± 5% or less, ± 4% or less, ± 3% or less, ± 2% or less, ± 1% or less, ± 0. It can represent a range of change of 5.5% or less, ± 0.1% or less, or ± 0.05% or less. For example, the difference between two numbers is ± 10% or less of the mean of the numbers (eg ± 5% or less, ± 4% or less, ± 3% or less, ± 2% or less, ± 1% or less, ± 0). If it is 5.5% or less, ± 0.1% or less, or ± 0.05% or less), the above two values are considered to be "generally" the same.

Also, in the present specification, quantities, ratios and other numerical values may be expressed in the form of a range. The format of such ranges should be understood for convenience and brevity, not only to include numbers explicitly specified to be limited by the range, but also to explicitly specify each number and subrange. It should be flexibly understood to include all individual numerical values or sub-ranges contained within the above range, as specified in the above.

A list of items connected by the terms "at least one of them", "at least one of them", "at least one of them" or other similar terms in the form and claims for carrying out the invention. Can mean any combination of listed items. For example, when items A and B are listed, the phrases "at least one of A and B" and "at least one of A or B" mean A only, B only, or A and B. .. In another example, when items A, B and C are listed, the phrases "at least one of A, B and C" and "at least one of A, B or C" are A only, B. Only, C only, A and B (excluding C), A and C (excluding B), B and C (excluding A), or all of A, B and C. Item A may include a single component (component) or a plurality of components. Item B may include a single component or a plurality of components. Item C may include a single component or a plurality of components.

As used herein, the term "hydrocarbon group" includes an alkyl group, an alkenyl group and an alkynyl group. For example, what is intended by a hydrocarbon group is a linear hydrocarbon structure with 1-10 carbon atoms. A "hydrocarbon group" is also intended to be a branched or cyclic hydrocarbon structure with 3-10 carbon atoms. When a hydrocarbon group having a specific carbon number is identified, it is intended to include all geometric isomers having that carbon number. Further, the hydrocarbon group in the present specification is a hydrocarbon group having 1 to 8 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, and a hydrocarbon group having 1 to 4 carbon atoms. There may be. Further, the hydrocarbon group may be optionally substituted. For example, the hydrocarbon group may be substituted with a halogen or alkyl group containing fluorine, chlorine, bromine and iodine.

Intended by the term "alkyl group" is a linear saturated hydrocarbon structure with 1-10 carbon atoms. The "alkyl group" is also intended to be a branched chain or cyclic hydrocarbon structure with 3-10 carbon atoms. For example, the alkyl group may be an alkyl group having 1 to 8 carbon atoms, an alkyl group having 1 to 6 carbon atoms, and an alkyl group having 1 to 4 carbon atoms. When an alkyl group having a specific carbon number is identified, it is intended to include all geometric isomers having that carbon number. Thus, for example, "butyl group" means to include n-butyl group, sec-butyl group, isobutyl group, tert-butyl group and cyclobutyl group, and "propyl group" means n-propyl group, isopropyl group and Contains a cyclopropyl group. Examples of alkyl groups are methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, cyclobutyl group, n-pentyl group, Includes isopentyl group, neopentyl group, cyclopentyl group, methylcyclopentyl group, ethylcyclopentyl group, n-hexyl group, isohexyl group, cyclohexyl group, n-heptyl group, octyl group, cyclopropyl group, cyclobutyl group, norbornyl group, etc. Not limited to these. Further, the alkyl group may be optionally substituted.

The term "alkenyl group" refers to a monovalent unsaturated hydrocarbon group that is straight or has a branched chain and has at least one, usually one, two or three carbon-carbon double bonds. Point to. Unless otherwise defined, the alkenyl group usually has 2 to 10 carbon atoms, eg, an alkenyl group having 6 to 10 carbon atoms, or an alkenyl group having 2 to 8 carbon atoms or 2 It may be an alkenyl group having up to 6 carbon atoms. Representative alkenyl groups (eg) include a vinyl group, an n-propenyl group, an isopropenyl group, an n-but-2-enyl group, a pig-3-enyl group, an n-hex-3-enyl group and the like. Further, the alkenyl group may be optionally substituted.

The term "alkynyl group" refers to a monovalent unsaturated hydrocarbon group that is straight or has a branched chain and has at least one, usually one, two or three carbon-carbon triple bonds. Unless otherwise specified, the alkynyl group usually has 2 to 10 carbon atoms, eg, an alkynyl group having 6 to 10 carbon atoms, or an alkynyl group having 2 to 8 carbon atoms or 2 It may be an alkynyl group having up to 6 carbon atoms. Representative alkynyl groups (eg) include ethynyl groups, prop-2-ynyl (normal-propynyl groups), normal-butyl-2-alkynyl groups, normal-hexyl-3 alkynyl groups and the like. Further, the alkynyl group may be optionally substituted.

As used herein, the term "halogen" may be F, Cl, Br or I.

1. Electrolyte The present application provides an electrolytic solution containing fluoroethylene carbonate (FEC) and a silicate compound.

In some examples, the structure of the silicate compound is set forth in Formula I.

式中、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４はそれぞれ、置換又は無置換のＣ_１～Ｃ_１０炭化水素基、置換又は無置換のＣ_１～Ｃ_６炭化水素基、又は置換又は無置換のＣ_１～Ｃ_４炭化水素基から独立して選択され、置換の場合、置換基は、ハロゲンである。いくつかの実施例では、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４はそれぞれ、置換又は無置換のＣ_１～Ｃ_４アルキル基から独立して選択され、置換の場合、置換基は、ハロゲンである。更なるいくつかの実施例では、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４はそれぞれ、メチル基、エチル基又はプロピル基から独立して選択される。

In the formula, R ₁ , R ₂ , R ₃ and R ₄ are substituted or unsubstituted C ₁ to C ₁₀ hydrocarbon groups, substituted or unsubstituted C ₁ to C ₆ hydrocarbon groups, or substituted or unsubstituted, respectively. Independently selected from the C ₁ to C ₄ hydrocarbon groups of, and in the case of substitution, the substituent is a halogen. In some embodiments, R ₁ , R ₂ , R ₃ and R ₄ are selected independently of the substituted or unsubstituted C ₁ to C ₄ alkyl groups, respectively, and in the case of substitution, the substituent is a halogen. be. In some further examples, R ₁ , R ₂ , R ₃ and R ₄ are selected independently of the methyl, ethyl or propyl groups, respectively.

In some examples, the silicate compound of the formula I in the electrolytic solution is at least one selected from the following compounds 1 to 3.

In some examples, the silicate compound of formula I is tetraethyl orthosilicate (Compound 1).

In some examples, the mass ratio of the silicate compound to the fluoroethylene carbonate (FEC) is from about 1: 1 to about 1:10. In some examples, the mass ratio of the silicate compound to the fluoroethylene carbonate (FEC) is from about 1: 2 to about 1: 6, and in some examples, the silicate compound and the fluoroethylene. The mass ratio with carbonate (FEC) is from about 1: 3 to about 1: 5. In some embodiments, the mass ratio is about 1: 2, about 1: 3, about 1: 4, about 1: 5, about 1: 6 or about 1: 7. When the silicate compound and the fluoroethylene carbonate are added to the electrolytic solution and both are in the above range, the electrolytic solution is stabilized and a dense protective layer is formed on the surface of the positive electrode to improve the cycle performance and rate performance of the battery. be able to.

In some embodiments, the content of the silicate compound is from about 0.1% to about 5% by weight of the total weight of the electrolyte. In some embodiments, the content of the silicate compound is from about 0.5% to about 4% by weight of the total weight of the electrolyte. In some embodiments, the content of the silicate compound is from about 1% to about 3% by weight of the total weight of the electrolyte. In some embodiments, the content of the silicate compound is from about 1.5% by weight to about 2% by weight of the total weight of the electrolyte. In some embodiments, the content of the silicate compound is about 0.5% by weight, about 1% by weight, about 1.5% by weight, about 2% by weight, about 2.5% of the total weight of the electrolyte. By weight%, about 3% by weight, about 3.5% by weight or about 4% by weight. If the content is lower than 0.1% by weight, the improvement in the stability of the electrolytic solution is limited, and if it is larger than 5% by weight, the film formed on the positive electrode becomes too thick, which affects the transmission of Li ⁺ . Given, thereby degrading cell resistance and cycle performance.

In some embodiments, the electrolyte further comprises a cyclic carboxylic acid anhydride compound comprising at least one of a formula II, formula III or formula IV structure.

式中、Ｒ_５、Ｒ_６、Ｒ_７、Ｒ_８、Ｒ_９、Ｒ_１０及びＲ_１１はそれぞれ、水素、ハロゲン、置換又は無置換のＣ_１～Ｃ_１０炭化水素基、置換又は無置換のＣ_１～Ｃ_６炭化水素基、又は置換又は無置換のＣ_１～Ｃ_４炭化水素基から独立して選択され、置換の場合、置換基は、ハロゲンである。いくつかの実施例では、Ｒ_５、Ｒ_６、Ｒ_７、Ｒ_８、Ｒ_９、Ｒ_１０及びＲ_１１はそれぞれ、置換又は無置換のＣ_１～Ｃ_４アルキル基から独立して選択され、置換の場合、置換基は、ハロゲンである。更なるいくつかの実施例では、Ｒ_５、Ｒ_６、Ｒ_７、Ｒ_８、Ｒ_９、Ｒ_１０及びＲ_１１はそれぞれ、水素又はメチル基から独立して選択される。

In the formula, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ and R ₁₁ are hydrogen, halogen, substituted or unsubstituted C ₁ to C ₁₀ hydrocarbon groups, substituted or unsubstituted C, respectively. It is independently selected from ₁ to C ₆ hydrocarbon groups or substituted or unsubstituted C ₁ to C ₄ hydrocarbon groups, and in the case of substitution, the substituent is a halogen. In some embodiments, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ and R ₁₁ are each independently selected and substituted from substituted or unsubstituted C ₁ to C ₄ alkyl groups, respectively. In the case of, the substituent is a halogen. In some further embodiments, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ and R ₁₁ are each selected independently of the hydrogen or methyl group.

In some embodiments, the cyclic carboxylic acid anhydride is at least one of maleic acid anhydride, succinic acid anhydride, 2-methylsuccinic acid anhydride, 2,3-dimethylsuccinic acid anhydride or glutaric acid anhydride. Includes one.

In some examples, the content of the cyclic carboxylic acid anhydride accounts for about 0.1% by weight to about 5% by weight of the total weight of the electrolyte, and in some examples, the cyclic carboxylic acid. The content of the anhydride accounts for about 0.5% by weight to about 4% by weight of the total weight of the electrolytic solution, and in some examples, the content of the cyclic carboxylic acid anhydride is the content of the electrolytic solution. It accounts for about 1% by weight to about 3% by weight of the total weight, and in some embodiments, the content of the cyclic carboxylic acid anhydride is from about 1.5% by weight to about 2% by weight of the total weight of the electrolyte. In some embodiments, the content of the cyclic carboxylic acid anhydride is about 0.5% by weight, about 1% by weight, about 1.5% by weight, about 2% of the total weight of the electrolyte. It accounts for% by weight, about 2.5% by weight, about 3% by weight, about 3.5% by weight or about 4% by weight. When the cyclic carboxylic acid anhydride is added to the electrolytic solution, the cyclic carboxylic acid anhydride has a high reduction potential, so that it is more preferentially reduced to a dense SEI film at the negative electrode and formed by the silicate compound and FEC. The SEI to be made is further modified to facilitate the passage of Li ⁺ and further improve the battery rate and cycle performance. If the content of the cyclic carboxylic acid anhydride is too low, it is insufficient to form stable protection at the interface of the negative electrode, and the effect of improving the cycle performance cannot be obtained, so that the cyclic carboxylic acid anhydride is not obtained. If the content of the substance is too high, the formed film is too thick, which causes a decrease in battery capacity and an increase in battery resistance.

In some embodiments, the electrolytic solution further comprises a disulfonic acid ester compound having the formula V.

式中、ｎは１～４の整数である。

In the formula, n is an integer of 1 to 4.

In some examples, the disulfonic acid ester compound is selected from methylenemethane disulfonate (MMDS).

In some examples, the content of the disulfonic acid ester compound accounts for about 0.1% by weight to about 5% by weight of the total weight of the electrolyte, and in some examples, the disulfonic acid ester compound. The content of the disulfonic acid ester compound accounts for about 0.5% by weight to about 4% by weight of the total weight of the electrolytic solution, and in some examples, the content of the disulfonic acid ester compound is the total weight of the electrolytic solution. It accounts for about 1% by weight to about 3% by weight, and in some embodiments, the content of the disulfonic acid ester compound accounts for about 1.5% by weight to about 2% by weight of the total weight of the electrolyte. In some embodiments, the disulfonic acid ester compound is about 0.5% by weight, about 1% by weight, about 1.5% by weight, about 2% by weight, about 2.5% by weight of the total weight of the electrolyte. %, About 3% by weight, about 3.5% by weight or about 4% by weight. By adding the disulfonic acid ester compound to the electrolytic solution, an SEI film having excellent stability is formed at the positive electrode, and the elution of the transition metal in the positive electrode material is suppressed to reduce direct contact with the electrolytic solution. Thereby, the rate performance and the cycle performance of the battery are further improved.

In some examples, the electrolyte further comprises at least one of unsaturated cyclic carbonate, cyclic sultone, cyclic sulfate lactone, nitrile compound or LiPO ₂ F ₂ as an additive. In some embodiments, the unsaturated cyclic carbonate ester comprises at least one of vinylene carbonate (VC) or vinylethylene carbonate (VEC) and the cyclic sulton is 1,3-propanesulton (PS). , 1,4-Butansulton (BS) or 1,3-Propensulton (PST), wherein the cyclic sulfate lactone is ethylene sulfate (DTD), propylene sulfate or 4-methylethylene sulfate (4). -Esteryl methylsulfate), and the nitrile compound is succinonitrile (SN), glutaronitrile, adiponitrile, 2-methyleneglutaronitrile, dipropylmalononitrile, 1, 3, 6 -Contains at least one of hexanetricarbonitrile, 1,2,6-hexanetricarbonitrile, 1,3,5-pentanetricarbonitrile or 1,2-bis (2-cyanoethoxy) ethane.

In some examples, the content of the additive accounts for about 0.1% to about 13% by weight of the total weight of the electrolyte, and in some examples, the content of the additive is. , About 0.5% by weight to about 10% by weight of the total weight of the electrolytic solution, and in some embodiments, the content of the additive is about 0.5% by weight of the total weight of the electrolytic solution. It accounts for ~ about 8% by weight, and in some examples the content of the additive accounts for about 1% by weight to about 7% by weight of the total weight of the electrolyte, and in some examples the said. The content of the additive accounts for about 1.5% by weight to about 6% by weight of the total weight of the electrolytic solution, and in some embodiments, the additive is about 0% by weight of the total weight of the electrolytic solution. 5% by weight, about 1% by weight, about 1.5% by weight, about 2% by weight, about 2.5% by weight, about 3% by weight, about 3.5% by weight or about 4% by weight, about 4.5% by weight %, About 5% by weight, about 5.5% by weight, about 6% by weight, about 6.5% by weight, about 7% by weight, about 7.5% by weight, about 8% by weight, about 8.5% by weight, It occupies about 9% by weight or about 9.5% by weight.

In some examples, the LiPO ₂ F ₂ content is from about 0.1% to about 2% by weight of the total weight of the electrolyte, and in some examples, the LiPO ₂ F ₂ The content of LiPO 2 F 2 is about 0.1% by weight to about 1% by weight of the total weight of the electrolytic solution, and in some embodiments, the content of LiPO ₂ F ₂ is the total weight of the electrolytic solution. It is about 0.1% by weight to about 0.6% by weight.

In some examples, the content of the unsaturated cyclic carbonate is from about 0.01% to about 2% by weight of the total weight of the electrolyte, and in some examples the unsaturated cyclic. The content of the carbonic acid ester is about 0.01% by weight to about 1.5% by weight of the total weight of the electrolytic solution, and in some examples, the content of the unsaturated cyclic carbonate is the electrolytic solution. It is about 0.01% by weight to about 1% by weight of the total weight of the liquid.

In some examples, the content of the annular sultone is from about 0.01% to about 3% by weight of the total weight of the electrolyte, and in some examples the content of the annular sultone is. , About 0.1% by weight to about 2% by weight of the total weight of the electrolytic solution, and in some embodiments, the content of the annular sultone is about 0.5% by weight of the total weight of the electrolytic solution. ~ About 1.5% by weight.

In some examples, the content of the cyclic sulfate lactone is from about 0.01% by weight to about 3% by weight of the total weight of the electrolyte, and in some examples, the content of the cyclic sulfate lactone. The amount is from about 0.1% by weight to about 2% by weight of the total weight of the electrolytic solution, and in some examples, the content of the cyclic sulfuric acid lactone is about 0. It is 5% by weight to about 1.5% by weight.

In some examples, the content of the nitrile compound is from about 0.5% to about 7% by weight of the total weight of the electrolytic solution, and in some examples, the content of the nitrile compound is. , About 0.5% by weight to about 5% by weight of the total weight of the electrolytic solution, and in some embodiments, the content of the nitrile compound is about 0.5% by weight of the total weight of the electrolytic solution. It is about 3% by weight, and in some examples, the content of the nitrile compound is about 1% by weight to about 2% by weight of the total weight of the electrolytic solution.

In some embodiments, the electrolyte further comprises an organic solvent and a lithium salt.

In some embodiments, the organic solvent comprises cyclic esters and chain esters having a mass ratio of about 1: 9 to about 7: 3, where the cyclic esters are ethylene carbonate (EC), propylene carbonate ( It is at least one selected from PC), γ-butyrolactone (BL), ethylene carbonate substituted with a fluorine-containing group, or propylene carbonate, and the chain ester is dimethyl carbonate (DMC), diethyl carbonate (DEC). , Ethyl Methyl Carbonate (EMC), Ethyl Acetate (EA), Methyl formate (MF), Ethyl formate (MA), Ethyl propionate (EP), Propionate propyl ester (PP), Methyl butyrate (MB), Fluoroethyl methyl At least one selected from carbonate and ethyl fluoropropionate. In some examples, the content of the organic solvent is from about 60% to about 95% by weight of the total weight of the electrolyte, and in some examples, the content of the organic solvent is said. It is about 60% by weight to about 90% by weight of the total weight of the electrolytic solution. In some embodiments, the content of the organic solvent is from about 70% by weight to about 85% by weight of the total weight of the electrolytic solution.

In some embodiments, the lithium salt is at least one of an organolithium salt or an inorganic lithium salt. In some embodiments, the lithium salt comprises at least one of a fluorine element, a boron element, or a phosphorus element. In some examples, the lithium salt is lithium hexafluorophosphate (LiPF ₆ ), lithium difluorophosphate, bis (trifluoromethanesulfonyl) imide lithium LiN (CF ₃ SO ₂ ) ₂ , bis (fluorosulfonyl) imide. Lithium Li (N (SO ₂ F) ₂ , lithium difluorooxalate volate LiB (C ₂ O ₄ ) ₂ , difluoroboranyl lithiooxalate LiBF 2 (C ₂ O ₄ ), lithium hexafluorophosphate (LiAsF ₆ ), excess It is at least one selected from lithium chlorate (LiClO ₄ ) and lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ). In some examples, the lithium salt may be lithium hexafluorophosphate. In some examples, the concentration of the lithium salt is from about 0.5 mol / L to about 1.8 mol / L. In some examples, the concentration of the lithium salt is about 0.8 mol / L. It is about 1.5 mol / L. In some examples, the concentration of the lithium salt is about 0.8 mol / L to about 1 mol / L.

2. Electrochemical devices The electrochemical devices of the present application include any device in which an electrochemical reaction occurs, and specific examples thereof include all kinds of primary batteries, secondary batteries, fuel cells, solar cells or capacitors. .. In particular, the electrochemical device is a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery. In some embodiments, the electrochemical device of the present application is disposed between a positive electrode having a positive electrode active material capable of storing and releasing metal ions, a negative electrode having a negative electrode active material capable of storing and releasing metal ions, and a positive electrode and a negative electrode. It contains the separated separator (diaphragm) and the electrolytic solution of the present application.

(Electrolytic solution)
The electrolytic solution used in the electrochemical device of the present application is one of the above-mentioned electrolytic solutions of the present application. Further, the electrolytic solution used for the electrochemical device of the present application may further contain other electrolytic solutions within a range not deviating from the gist of the present application.

(Positive electrode)
The positive electrode material used in the electrochemical device of the present application can be manufactured by a material, structure and manufacturing method known in the art. In some embodiments, the techniques described in US Pat. No. 9812739B, incorporated herein by reference in full text, can be used to produce the positive electrodes of the present application.

In some embodiments, the positive electrode comprises a current collector and a positive electrode active material layer disposed on the current collector. The positive electrode active material contains at least one lithium-ized interlayer compound that reversibly occludes and releases lithium ions. In some embodiments, the positive electrode active material comprises a composite oxide. In some embodiments, the composite oxide comprises lithium and at least one element selected from cobalt, manganese and nickel.

In some embodiments, the positive electrode active material is a lithium nickel cobalt manganese (NCM) ternary material, lithium iron phosphate (LiFePO ₄ ), LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , LiCo _{1- y} My O. ₂ , LiNi _{1-y My} O ₂ , LiMn _{2- y} My O ₄ , LiNi _x Coy Mn _z M _{1-x-y-z O 2} , where M is Fe, Co, Ni, Mn. , Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V, Ti, and 0 ≦ y ≦ 1, 0 ≦ x ≦ 1, 0 ≦ z ≦ 1. , X + y + z ≦ 1 or any combination thereof.

In some embodiments, the positive electrode active material may have a coating layer on its surface or may be mixed with another compound having a coating layer. The coating layer is at least one coating element compound selected from oxides of coating elements, hydroxides of coating elements, oxyhydroxides of coating elements, oxycarbonates of coating elements and hydroxycarbonates of coating elements. Is. The compound used for the coating layer may be amorphous or crystalline.

In some embodiments, the coating elements contained in the coating layer are Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, P or theirs. Any combination may be included. In some embodiments, the coatings in the coating layer are AlPO ₄ , Mg ₃ (PO ₄ ) ₂ , Co ₃ (PO ₄ ) ₂ , AlF ₃ , MgF ₂ , CoF ₃ , NaF, B ₂ O ₃ . It may be at least one of them. In some embodiments, the content of the coating element in the coating layer is from about 0.01% to about 10% by weight, based on the total weight of the positive electrode active material. The coating layer can be applied by any method as long as it does not adversely affect the performance of the positive electrode active material. For example, the method may include any coating method known in the art such as spraying, impregnation and the like.

The positive electrode active material layer further contains a pressure-sensitive adhesive and optionally a conductive material. The pressure-sensitive adhesive strengthens the bond between the positive electrode active material particles and strengthens the bond between the positive electrode active material and the current collector.

In some examples, the pressure-sensitive adhesive is polyvinyl alcohol, hydroxypropyl cellulose, cellulose acetate, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl chloride, ethyleneoxy-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, Includes, but is not limited to, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic acid (esterified) styrene-butadiene rubber, epoxy resin, nylon and the like.

In some embodiments, the conductive material includes, but is not limited to, carbon-based materials, metal-based materials, conductive polymers and mixtures thereof. In some embodiments, the carbon-based material is selected from natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanotubes, graphene or any combination thereof. In some embodiments, the metal-based material is selected from metal powder, metal fibers, copper, nickel, aluminum and silver. In some examples, the conductive polymer is a polyphenylene derivative.

In some embodiments, the current collector may be, but is not limited to, aluminum.

The positive electrode can be manufactured by a manufacturing method known in the art. For example, a positive electrode can be obtained by mixing an active material, a conductive material and a pressure-sensitive agent in a solvent to produce an active material composition, and coating the active material composition on a current collector. In some embodiments, the solvent may include, but is not limited to, N-methylpyrrolidone and the like.

In some embodiments, the positive electrode is manufactured by forming a positive electrode material on a current collector using a positive electrode active material layer containing a lithium transition metal compound powder and a binder.

In some embodiments, the positive electrode active material layer is usually obtained by dry mixing the positive electrode active material with a binder (such as a conductive material and a thickener used as needed) to form a sheet. It is produced by crimping a sheet-like material onto a positive electrode current collector, or by dissolving or dispersing these materials in a liquid medium to form a slurry, which is applied to the positive electrode current collector and dried. In some embodiments, the material of the positive electrode active material layer includes any material known in the art.

(Negative electrode)
The material, configuration and method of manufacturing the negative electrode used in the electrochemical device of the present application may include any technique disclosed in the prior art. In some embodiments, the negative electrode is the negative electrode described in US Pat. No. 9812739B, which is incorporated herein by reference in its entirety.

In some embodiments, the negative electrode comprises a current collector and a negative electrode active material layer disposed on the current collector. The negative electrode active material includes a material that reversibly occludes / releases lithium ions. In some embodiments, the material that reversibly occludes / releases lithium ions comprises a carbon material. In some embodiments, the carbon material may be any carbon-based negative electrode active material commonly used in lithium ion rechargeable batteries. In some embodiments, the carbon material comprises, but is not limited to, crystalline carbon, amorphous carbon or mixtures thereof. The crystalline carbon may be amorphous, sheet-like, fragmentary, spherical or fibrous natural graphite or artificial graphite. The amorphous carbon may be soft carbon, hard carbon, mesophase pitch carbide, calcined coke and the like.

In some embodiments, the negative electrode active material layer comprises a negative electrode active material. In some embodiments, the negative electrode active material is lithium metal, structured lithium metal, natural graphite, artificial graphite, mesocarbon microbeads (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, Li-. It includes, but is not limited to, Sn alloys, Li—Sn—O alloys, Sn, SnO, SnO ₂ , lithium thio ₂ -Li ₄ Ti ₅ O ₁₂ , Li—Al having a spinel structure, or any combination thereof.

When the negative electrode contains a silicon carbide compound, silicon: carbon = about 1:10 to 10: 1 based on the total weight of the negative electrode active material, and the median diameter D50 of the silicon carbide compound is about 0.1 micrometer to 20. It is a micrometer. When the negative electrode contains an alloy material, the negative electrode active material layer can be formed by a method such as a vapor deposition method, a sputtering method, or a plating method. When the negative electrode contains lithium metal, for example, a spherical ridge-shaped conductive skeleton and metal particles scattered in the conductive skeleton are used to form a negative electrode active material layer. In some embodiments, the spherical ridge-shaped conductive skeleton may have a porosity of 5% to 85%. In some embodiments, the lithium metal negative electrode active material layer is further fitted with a protective layer.

In some embodiments, the negative electrode active material layer may comprise a pressure-sensitive adhesive and optionally contains a conductive material. The pressure-sensitive adhesive strengthens the bond between the negative electrode active material particles and the bond between the negative electrode active material and the current collector. In some examples, the pressure-sensitive adhesive is polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, cellulose acetate, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethyleneoxy-containing polymer, polyvinylpyrrolidone, polyurethane, polytetra. Includes, but is not limited to, fluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene butadiene rubber, acrylic acid (esterified) styrene butadiene rubber, epoxy resins, nylon and the like.

In some embodiments, the conductive material includes, but is not limited to, carbon-based materials, metallic materials, conductive polymers or mixtures thereof. In some embodiments, the carbon-based material is selected from natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber or any combination thereof. In some embodiments, the metal-based material is selected from metal powder, metal fibers, copper, nickel, aluminum and silver. In some examples, the conductive polymer is a polyphenylene derivative.

In some embodiments, collectors include copper foils, nickel foils, stainless steel foils, titanium foils, nickel foam, copper foam, polymer substrates coated with conductive metals and combinations thereof. Not limited.

The negative electrode can be manufactured by a manufacturing method known in the art. For example, the negative electrode is obtained by mixing an active material, a conductive material and a pressure-sensitive agent in a solvent to produce an active material composition, and coating the active material composition on a current collector. In some embodiments, the solvent may include, but is not limited to, water and the like.

(Separator)
In some embodiments, the electrochemical device of the present application is provided with a separator to prevent a short circuit between the positive and negative electrodes. The material and shape of the separator used in the electrochemical device of the present application are not particularly limited, and may be any technique disclosed in the prior art. In some embodiments, the separator comprises a polymer or inorganic material formed of a stable material in the electrolyte of the present application.

For example, the separator may include a substrate layer and a surface treatment layer. The base material layer is a non-woven fabric, a film or a composite film having a porous structure, and the material of the base material layer is at least one selected from polyethylene, polypropylene, polyethylene terephthalate and polyimide. Specifically, polypropylene porous film, polyethylene porous film, polypropylene non-woven fabric, polyethylene non-woven film or polypropylene-polyethylene-polypropylene porous composite film may be selected and used. The substrate layer may be one or more layers, and if the substrate layer is multiple layers, the composition of the polymers in the different substrate layers may be the same or different, and the polymers in the different substrate layers. The weight average molecular weights of the polymers are not exactly the same, and when the substrate layer is a plurality of layers, the pore closing temperature of the polymer differs depending on the substrate layer.

In some embodiments, the surface treatment layer is placed on at least one surface of the substrate layer, and the surface treatment layer may be a polymer layer or an inorganic layer, and is a layer formed by mixing a polymer and an inorganic substance. There may be.

The inorganic layer contains inorganic particles and an adhesive, and the inorganic particles include aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, and oxidation. It is one or a combination of two selected from yttrium, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium sulfate. Adhesives are polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylic acid salt, polyvinylpyrrolidone, polyvinyl ether, polymethylmethacrylate, polytetrafluoroethylene. And one or a combination of two selected from polyhexafluoropropylene. The polymer layer contains a polymer, and the polymer material is polyamide, polyacrylonitrile, acrylic acid ester polymer, polyacrylic acid, polyacrylic acid salt, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride or poly (vinylidene fluoride-hexafluoropropylene). ) Includes at least one of.

3. Application Since the electrolytic solution according to the present application can improve the high temperature storage performance and the cycle performance of the electrochemical device, the electrochemical device manufactured by the electrolytic solution is applied to electronic devices in various fields.

The application of the electrochemical device of the present application is not particularly limited, and can be used for any application known in the prior art. In one embodiment, the electrochemical device of the present application is a laptop computer, a pen input computer, a mobile computer, an electronic book player, a mobile phone, a mobile fax machine, a mobile copy, a mobile printer, a headphone stereo, a video movie, an LCD TV, a handy cleaner. , Portable CDs, mini disks, transceivers, electronic notebooks, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, bikes, motorized bicycles, bicycles, lighting equipment, toys, game equipment, watches, power tools , Flashes, cameras, large household storage batteries, lithium ion capacitors, etc., but are not limited thereto.

Hereinafter, the present application will be described in more detail with reference to Examples and Comparative Examples, but the present application is not limited to these Examples as long as the gist of the present application is not deviated.

1. 1. Manufacture of Lithium Ion Battery (1) Manufacture of Positive Electrode Lithium manganate (LiMn ₂ O ₄ ), conductive agent (conductive carbon of Super P®), polyvinylidene fluoride (PVDF) in 96: 2: 2 weight Mix by ratio, add N-methylpyrrolidone (NMP), stir uniformly by the action of a vacuum stirrer to obtain a positive electrode slurry with a solid content of 72 wt%, and make the positive electrode slurry 13 micrometer thick. The aluminum foil is uniformly applied onto the aluminum foil, dried at 85 ° C., then cold-rolled, cut, cut out, and then dried under vacuum conditions at 85 ° C. for 4 hours to obtain a positive electrode.

(2) Manufacture of Negative Electrode 96.4: 1.5: 0.5: Artificial graphite, conductive agent (conductive carbon of Super P (registered trademark)), sodium carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR): Mix at a weight ratio of 1.6, add deionized water, and use a vacuum stirrer to obtain a negative electrode slurry having a solid content of 54 wt%. The negative electrode slurry is uniformly applied onto the copper foil, which is the negative electrode current collector, and the copper foil is dried at 85 ° C., then cold-rolled, cut, cut out, and then dried under vacuum conditions at 120 ° C. for 12 hours. To obtain a negative electrode.

(3) Production of electrolytic solution In a glove box with a dry argon atmosphere, ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are placed in a mass of EC: EMC: DEC = 3: 5: 2. The mixture is mixed by ratio, then a specific amount and type of additive is added, dissolved and sufficiently stirred, then the lithium salt LiPF ₆ is added, and the mixture is uniformly mixed to obtain an electrolytic solution. The concentration of LiPF ₆ is 1 mol / L. The specific types and contents of the additives used in the electrolytic solution are as shown in the table below, and the content of the additives is a mass percentage calculated based on the total mass of the electrolytic solution.

(4) Manufacture of separator Select a polyethylene (PE) separator with a thickness of 12 micrometers.

(5) Manufacture of lithium-ion batteries The positive electrode, separator, and negative electrode are stacked in order, and the separator is placed between the positive electrode and the negative electrode to give it a separation function. To get. The electrode assembly is placed in a packaging bag, dried, injected with the electrolyte produced above, vacuum sealed, allowed to stand, chemicalized (charged to 3.3 V with a constant current of 0.02 C, and further 0.1 C. A lithium-ion battery is obtained through processes such as charging up to 3.6 V with a constant current), shaping, and a capacity test.

2. 2. Performance test of lithium-ion battery (1) Rate test of lithium-ion battery at 25 ° C Put the lithium-ion battery in an incubator (constant temperature) at 25 ° C and let it stand for 30 minutes to bring the lithium-ion battery to a constant temperature. do. A lithium ion battery that has reached a certain temperature is charged with a constant current of 0.5 C until the voltage reaches 4.2 V, and then charged with a constant voltage of 4.2 V until the current reaches 0.05 C. Discharge to 3.0V at 5C / 1C / 2C / 5C rates, record the discharge capacity at different rates, and calculate the 5C discharge capacity retention rate with the 0.5C discharge capacity as 100%.

(2) Cycle performance of lithium-ion battery at 25 ° C. Place the lithium-ion battery in an incubator at 25 ° C and let it stand for 30 minutes to bring the lithium-ion battery to a constant temperature. A lithium ion battery that has reached a certain temperature is charged with a constant current of 0.5 C until the voltage reaches 4.2 V, then charged with a constant voltage of 4.2 V until the current reaches 0.05 C, and then 1 C. Discharge until the voltage reaches 3.0 V at the constant current of, and this is regarded as one charge / discharge cycle. With the initial discharge capacity as 100%, the charge / discharge cycle is repeated for 500 cycles, the test is stopped, the cycle capacity retention rate is recorded, and the cycle performance of the lithium ion battery is evaluated.

The cycle capacity retention rate is the capacity when cycling to a certain cycle divided by the capacity at the time of the first discharge and multiplied by 100%.

(3) Cycle performance of lithium-ion battery at 45 ° C. Place the lithium-ion battery in an incubator at 45 ° C. and let it stand for 30 minutes to bring the lithium-ion battery to a constant temperature. A lithium ion battery that has reached a certain temperature is charged with a constant current of 0.5 C until the voltage reaches 4.2 V, then charged with a constant voltage of 4.2 V until the current reaches 0.05 C, and then 1 C. Discharge until the voltage reaches 3.0 V at the constant current of, and this is regarded as one charge / discharge cycle. With the initial discharge capacity as 100%, the charge / discharge cycle is repeated for 300 cycles, the test is stopped, the cycle capacity retention rate is recorded, and the cycle performance of the lithium ion battery is evaluated.

(4) Battery thickness expansion rate The battery thickness is measured, and the battery thickness expansion rate is calculated by the following formula.
Thickness expansion rate = (battery thickness after cycle-battery thickness before cycle) / battery thickness before cycle x 100%

A. According to the above method, the electrolytic solutions and lithium ion batteries of Examples 1 to 13 and Comparative Examples 1 to 7 are produced. Then, the rate discharge performance at 25 ° C., the cycle maintenance rate at 25 ° C., the cycle maintenance rate at 45 ° C., and the thickness expansion rate of the lithium ion battery were tested, and the test results are shown in Table 1.

As can be seen from the test results of Comparative Examples 1 to 6, the silicate compound and fluoroethylene carbonate (FEC) having a specific structure are not added to the electrolytic solution, or only one of the above is added. If not, the rate discharge performance and cycle performance of the battery are inferior, and the thickness expansion rate is high.

As can be seen from the data of Examples 1 to 13 and Comparative Examples 1 to 7, the rate discharge performance and cycle capacity of the battery are maintained by adding a specific ratio of the silicate compound and fluoroethylene carbonate (FEC). The rate can be effectively improved and the increase in battery thickness during the cycle process can be improved. Although not limited to any theory, the improvement in performance is due to the absorption of trace water and HF in the electrolyte by the silicate compound and the stability of the electrolyte. It helps to improve the properties, and at the same time, it is easily oxidized and forms a dense protective film on the positive electrode, and reduces the destruction of the positive electrode by the electrolytic solution. Fluoroethylene carbonate (FEC) has a high reduction potential and is preferentially reduced at the negative electrode during the first charge / discharge to form a film, and the formed film is dense and suppresses the decomposition reaction of the electrolytic solution at the negative electrode. There is. When the ratio of tetraethyl orthosilicate added to the electrolytic solution to FEC is in a specific range, the electrolytic solution can be more effectively stabilized and better interface protection can be formed on the positive and negative electrodes. If the ratio of tetraethyl orthosilicate to FEC is too high, the resistance to film formation is high, which increases the battery resistance and affects the battery performance. If the ratio is too low, effective interface protection is formed. However, the effect of improving the cycle performance of the battery cannot be obtained.

B. According to the above method, the electrolytic solutions and lithium ion batteries of Examples 14 to 24 and Comparative Examples 8 to 9 are produced. The rate discharge performance at 25 ° C., the cycle maintenance rate at 25 ° C., the cycle maintenance rate at 45 ° C., and the thickness expansion rate of the lithium ion battery are tested. The test results are shown in Table 2.

As can be seen based on the comparison of Examples 6 and 14 to 23, and the above Examples and Comparative Examples 8 to 9, the disulfonic acid ester compound (disulfonic acid ester compound) is further contained in the electrolytic solution containing tetraethyl orthosilicate and FEC. For example, by adding at least one of methylene methanedisulfonate MMDS) or cyclic carboxylic acid anhydride (eg, maleic acid anhydride, glutaric acid anhydride, succinic acid anhydride, etc.), the cycle performance of the battery, gas. The generation status and rate discharge performance can be further improved.

C. The electrolytic solutions and lithium ion batteries of Examples 25 to 34 are manufactured according to the above method. The rate discharge performance at 25 ° C., the cycle maintenance rate at 25 ° C., the cycle maintenance rate at 45 ° C., and the thickness expansion rate of the lithium ion battery are tested. The test results are shown in Table 3.

As can be seen from Examples 27 to 33 and Example 19, in the electrolytic solution containing tetraethyl orthosilicate, FEC and maleic anhydride, an additional 0.1% to about 13% of other additives (eg, for example). Battery cycle performance, gas by adding 1,3-propanesulton (PS), vinylene carbonate (VC), LiPO ₂ F ₂ , or at least one of 1,3,6-hexanetricarbonitrile). The generation status and rate discharge performance can be further improved. Also, as can be seen from the comparison between Examples 6 and 25 and 26, or from the comparison between Example 7 and Example 34, certain amounts of tetraethyl orthosilicate and FEC are contained in the electrolyte. Of other additives in quantity (eg, 1,3-propanesulton (PS), vinylene carbonate (VC), LiPO ₂ F ₂ , or 1,3,6-hexanetricarbonitrile or succinonitrile (SN). By adding at least one of the above), the normal temperature cycle performance and the high temperature cycle performance of the battery can be further improved. From the above experimental results, it has been clarified that the combined use of these additives is advantageous for enhancing the protection of the positive and negative electrodes of the battery, and therefore further improving the battery performance.

"Some examples", "partial examples", "one example", "another example", "example", "concrete example" or "partial example" in the entire specification. Citation means that at least one embodiment or example of the present application comprises the particular features, structures, materials or properties described in that example or example. Accordingly, statements appearing in each part of the entire specification, eg, "in some examples", "in an example", "in one example", "in another example", "in one example", "specification". "In an example" or "in an example" does not necessarily refer to the same embodiment or example in the present application. Also, the particular features, structures, materials or properties herein can be combined in any suitable manner in one or more examples or examples.

Although exemplary embodiments have been shown and described, those skilled in the art will not be able to interpret the above embodiments as limiting the present application and will not deviate from the spirit, principles and scope of the present application. It should be understood that changes, substitutions and modifications can be made.

Claims (10)

Includes fluoroethylene carbonate and silicate compounds of the structure of formula I

In the formula, R ₁ , R ₂ , R ₃ and R ₄ are selected independently of the substituted or unsubstituted C ₁ to C ₁₀ hydrocarbon groups, respectively, and in the case of substitution, the substituent is a halogen.
An electrolytic solution having a mass ratio of the silicate compound to the fluoroethylene carbonate of 1: 1 to 1:10. The electrolytic solution according to claim 1, wherein the silicate compound contains at least one of the following.

The electrolytic solution according to claim 1, wherein the content of the silicate compound is 0.1% by weight to 5% by weight of the total weight of the electrolytic solution. Further comprising a cyclic carboxylic acid anhydride compound comprising at least one of a compound of formula II structure, a compound of formula III structure or a compound of formula IV structure.

In the formula, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ and R ₁₁ are selected independently of hydrogen, halogen and substituted or unsubstituted C ₁ to C ₁₀ hydrocarbon groups, respectively. The electrolytic solution according to claim 1, wherein in the case of substitution, the substituent is a halogen. The cyclic carboxylic acid anhydride contains at least one of maleic acid anhydride, succinic acid anhydride, 2-methylsuccinic acid anhydride, 2,3-dimethylsuccinic acid anhydride or glutaric acid anhydride, and the cyclic carboxylic acid anhydride. The electrolytic solution according to claim 4, wherein the content of the carboxylic acid anhydride is 0.1% by weight to 5% by weight of the total weight of the electrolytic solution. Further comprising a disulfonic acid ester compound having formula V

The electrolytic solution according to claim 1, wherein n is an integer of 1 to 4 and the content of the disulfonic acid ester compound is 0.1% by weight to 5% by weight of the total weight of the electrolytic solution. .. The additive further contains at least one of LiPO ₂ F ₂ , unsaturated cyclic carbonate, cyclic sultone, cyclic sulfate lactone or a nitrile compound, and the content of the additive is 0 of the total weight of the electrolytic solution. . The electrolytic solution according to any one of claims 1 to 6, which is 1% by weight to 13% by weight. The content of the LiPO ₂ F ₂ is 0.001% by weight to 2% by weight of the total weight of the electrolytic solution.
The unsaturated cyclic carbonate contains at least one of vinylene carbonate and vinylethylene carbonate, and the content of the unsaturated cyclic carbonate is 0.001% by weight to 2% by weight based on the total weight of the electrolytic solution. And
The annular sultone contains at least one of 1,3-propane sultone, 1,4-butane sultone or 1,3-propene sultone, and the content of the annular sultone is 0. It is 01% by weight to 3% by weight,
The cyclic sulfate lactone contains at least one of ethylene sulfate, propylene sulfate or 4-methylethylene sulfate, and the content of the cyclic sulfate lactone is 0.01% by weight to 3% by weight of the total weight of the electrolytic solution. %, And the nitrile compound is succinonitrile, glutaronitrile, adiponitrile, 2-methyleneglutaronitrile, dipropylmarononitrile, 1,3,6-hexanetricarbonitrile, 1,2,6-hexane. It contains at least one of tricarbonitrile, 1,3,5-pentanetricarbonitrile or 1,2-bis (2-cyanoethoxy) ethane, and the content of the nitrile compound is the total weight of the electrolytic solution. The electrolytic solution according to claim 7, which is 0.5% by weight to 7% by weight of the above. An electrochemical device containing the electrolytic solution according to any one of claims 1 to 8. An electronic device including the electrochemical device according to claim 9.