WO2022000271A1

WO2022000271A1 - Electrolyte, and electrochemical device and electronic device comprising same

Info

Publication number: WO2022000271A1
Application number: PCT/CN2020/099306
Authority: WO
Inventors: 张丽兰; 唐超; 刘俊飞; 郑建明
Original assignee: 宁德新能源科技有限公司
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2022-01-06
Also published as: CN112956063A

Abstract

An electrolyte, containing a compound of formula (I), wherein any one of M₁ to M₅ is an M₇-OLi group; at least one of M₁ to M₅ is an M₈-CN group; the remaining M₁ to M₅ which are not the M₇-OLi group and M₈-CN group are each independently selected from hydrogen, a substituted or unsubstituted C_1-12 alkoxy, halogen, a substituted or unsubstituted C_1-12 alkyl, a substituted or unsubstituted C_2-12 alkenyl, a substituted or unsubstituted C_2-12 alkynyl, nitro, a sulfonic acid group, an aldehyde group, a carboxyl group, a silicon group, or a substituted or unsubstituted C_6-12 aryl, wherein when substituted, the substituent is halogen; and M₆, M₇ and M₈ are each independently selected from a C_0-5 hydrocarbylene, and a C_1-5 hydrocarbylene substituted with halogen. Also provided are an electrochemical device and an electronic device. The electrolyte can provide good high-temperature storage performance for the electrochemical device.

Description

Electrolyte and electrochemical and electronic devices containing the same

technical field

The present application relates to the technical field of energy storage, and in particular, to an electrolyte and an electrochemical device and an electronic device including the same.

Background technique

Electrochemical devices, such as lithium-ion batteries, have many advantages that make them widely used in various electronic devices. During the formation of a lithium battery, the solvent or additives in the electrolyte react on the surface of the positive and negative electrodes to generate a large amount of gas, especially when the battery is under extreme conditions, for example, during the high-temperature storage process at full charge, with the extension of the storage time, it will As a result, the continuous reaction between the positive and negative electrodes and the electrolyte causes more and more gas to accumulate in the battery and greatly reduces the safety of the battery. Therefore, it is necessary to develop a new electrolyte additive, which can form a stable protective layer on the electrode surface, so that the battery can effectively avoid the risk of flatulence even under extreme storage conditions.

SUMMARY OF THE INVENTION

In order to overcome the problem that lithium ion batteries are prone to flatulence during high temperature storage in the prior art, the present application provides an electrolyte, which can provide a stable protective layer on the positive and negative electrodes of an electrochemical device, so that the electrochemical The device can achieve good electrochemical properties, eg, good high temperature storage performance.

The purpose of this application can be achieved at least through the following technical solutions:

An electrolyte comprising a compound of formula I:

Wherein, any one of _{M 1} to M ₅ _{is M 7} -OLi group; and at least one of M ₁ to M ₅ _{is M 8} -CN group; the rest are not M ₇ -OLi group and M ₈ -CN group M ₁ to M _{5 of the} group are each independently selected from hydrogen, substituted or unsubstituted C _1-12 alkoxy, halogen, substituted or unsubstituted C _1-12 alkyl, substituted or unsubstituted Substituted C _2-12 alkenyl, substituted or unsubstituted C _2-12 alkynyl, nitro, sulfonic acid, aldehyde, carboxyl, silyl or substituted or unsubstituted C _6-12 aryl group, wherein when substituted, the substituent is halogen;

wherein M ₆ , M ₇ and M ₈ are each independently selected from C _0-5 hydrocarbylene, C _1-5 hydrocarbylene substituted by halogen.

In some embodiments, compounds of formula (I) of the present application include at least one of compounds of formula I-1 to formula I-6:

wherein, R ₁ -R ₁₄ are each independently selected from hydrogen, halogen, substituted or unsubstituted C _1-12 alkoxy, substituted or unsubstituted C _1-12 alkyl, substituted or unsubstituted Substituted C _2-12 alkenyl, substituted or unsubstituted C _2-12 alkynyl, nitro, sulfonic acid, aldehyde, carboxyl, silyl or substituted or unsubstituted C _6-12 aryl group, wherein when substituted, the substituent is halogen; and n is 0-5.

In some embodiments, compounds of Formula I include at least one of the following Compounds 1 to 16:

In some embodiments, the content of the compound of formula I described herein is about 0.01% to about 10% based on the total mass of the electrolyte.

In some embodiments, the electrolyte solution of the present application further includes at least one of additive A, additive B or additive C, wherein the additive A includes nitrile compounds, acid anhydride compounds, ether compounds, and phosphate ester compounds , at least one of phosphite compounds or borate compounds; the additive B comprises at least one of sulfate compounds, sulfite compounds, fluorocarbonates or unsaturated carbonates; the Additive C contains at least one of sulfonate-based compound, sulfone-based compound or lithium salt additive.

In some embodiments, based on the total mass of the electrolyte, the content of the additive A is about 0.01% to about 10%; the content of the additive B is about 0.01% to about 10%; the content of the additive C is From about 0.01% to about 5%.

In some embodiments, the nitrile compound includes at least one of the following compounds: succinonitrile, adiponitrile, 1,3,5-pentanetricarbonitrile, 1,3,6-hexanetricarbonitrile, 1,2, 6-Hexanetricarbonitrile, fumaric nitrile or ethylene glycol (bispropionitrile) ether;

The acid anhydride compounds include at least one of the following compounds: citric anhydride, succinic anhydride, maleic anhydride, trifluoromethyl maleic anhydride, dimethyl maleic anhydride or propane sulfonic anhydride;

Ether compounds include at least one of the following compounds: 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether or perfluorobutyl ether;

Phosphate compounds include at least one of the following compounds: triphenyl phosphate, tris(trifluoroethyl) phosphate or triallyl phosphate;

Phosphite compounds include at least one of the following compounds: triphenyl phosphite or trimethylsilyl phosphite;

The borate compound includes at least one of the following compounds: tris(hexafluoroisopropyl) borate, trimethylsilyl borate, trimethylene borate, triisopropyl borate, tributyl borate, boric acid triethyl ester or tripropyl borate;

Sulfate compounds include at least one of the following compounds: vinyl sulfate, vinyl bisulfate, vinyl methyl sulfate, vinyl ethyl sulfate or vinyl propyl sulfate;

The sulfite compounds include at least one of the following compounds: vinyl sulfite, methyl vinyl sulfite, ethyl vinyl sulfite, propyl vinyl sulfite or propylene sulfite;

Fluorocarbonates include at least one of the following compounds: fluoroethylene carbonate, methyl trifluoroethyl carbonate or trifluoromethyl ethylene carbonate;

Unsaturated carbonates include at least one of the following compounds: ethylene ethylene carbonate or vinylene carbonate;

Sulfonate compounds include at least one of the following compounds: 1,3-propane sultone, 1,4-butane sultone, 2,4-butane sultone, propenyl-1,3- Sultone, methylene methanedisulfonate or chain bissulfonate;

Sulfone compounds include at least one of the following compounds: sulfolane, sulfolane or 3-sulfolane;

Lithium salt additives include at least one of the following compounds: lithium 4,5-dicyano-2-(trifluoromethyl)imidazolium, lithium difluorophosphate, lithium tetrafluoroborate, lithium bisfluorosulfonimide, Lithium bistrifluorosulfonimide, lithium oxalate borate, or lithium bisfluorooxalate borate.

The present application also provides an electrochemical device comprising a positive electrode and an electrolyte according to the present application, the positive electrode including a positive electrode active material.

In some embodiments, the cathode active material includes at least one element selected from Al, Zr, or Mg.

In some embodiments, based on the total mass of the positive active material, the content a of Al is less than 1%, the content b of Zr is less than 1%, and the content c of Mg is less than 0.5%.

In some embodiments, the positive electrode material includes Al and Mg, and the content thereof satisfies the following condition: 0.005<a/c<500.

The present application also provides an electronic device comprising the electrochemical device according to the present application.

detailed description

Embodiments of the present application will be described in detail below. The relevant embodiments described herein are illustrative in nature and are used to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limitations of the present application.

As used herein, the term "about" is used to describe and account for small variations. When used in conjunction with an event or circumstance, the terms can refer to instances in which the event or circumstance occurs precisely as well as instances in which the event or circumstance occurs proximately. For example, when used in conjunction with a numerical value, a term may refer to a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, Less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, if the difference between two values is less than or equal to ±10% of the mean of the values (eg, less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%), then the two values are considered to be "about" the same.

In addition, amounts, ratios, and other numerical values are sometimes presented herein in a range format. It is to be understood that such range format is used for convenience and brevity, and that it is to be understood flexibly to include not only the numerical values expressly designated as the limits of the range, but also all individual numerical values or subranges subsumed within the stated range, as if expressly Specify each numerical value and subrange generically.

In the Detailed Description and the Claims, a list of items joined by the terms "one of," "one of," "one of," or other similar terms can mean that any of the listed items one. For example, if items A and B are listed, the phrase "one of A and B" means A only or B only. In another example, if the items A, B, and C are listed, the phrase "one of A, B, and C" means A only; B only; or C only. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements.

In the Detailed Description and the Claims, a list of items joined by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean the listed items any combination of . For example, if items A and B are listed, the phrase "at least one of A and B" means A only; B only; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, and C" means A only; or 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 contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements.

The following definitions are used in this application (unless expressly stated otherwise):

For simplicity, a "Cn-m" group refers to a group having "n" to "m" carbon atoms, where "n" and "m" are integers. For example, a "C _1-12 "hydrocarbyl group is a hydrocarbyl group having 1 to 12 carbon atoms, and a "C ₀ "hydrocarbylene group refers to a covalent bond.

The term "hydrocarbyl" encompasses alkyl, alkenyl, alkynyl, cycloalkyl, aryl groups. For example, a hydrocarbyl group is expected to be a straight chain hydrocarbon structure having 1 to 20 carbon atoms. "Hydrocarbyl" is also intended to be a branched or cyclic hydrocarbon structure having 3 to 20 carbon atoms. When specifying a hydrocarbyl group having a particular carbon number, it is intended to encompass all geometric isomers having that carbon number. The hydrocarbyl group herein may also be a hydrocarbyl group of 1 to 15 carbon atoms, a hydrocarbyl group of 1 to 10 carbon atoms, a hydrocarbyl group of 1 to 5 carbon atoms, a hydrocarbyl group of 5 to 20 carbon atoms, a hydrocarbyl group of 5 to 15 carbon atoms or a hydrocarbon group of 5 to 10 carbon atoms. Additionally, hydrocarbyl groups may be optionally substituted. For example, hydrocarbyl groups can be substituted with halogen, alkyl, aryl or heteroaryl groups including fluorine, chlorine, bromine and iodine.

The term "hydrocarbylene" refers to a straight or branched chain divalent hydrocarbon group linking an aryl group in the compounds of the present application to a -OLi or -CN group, wherein hydrocarbyl is as defined above. Exemplary hydrocarbylene groups include, but are not limited to: methylene, ethylene, propylene, n-butylene, vinylene, propenylene, n-butenylene, propynylene, n-butyne Base et al. The point of attachment of the hydrocarbylene to the aryl nucleus and to the -OLi or -CN group can be one carbon or any two carbons in the hydrocarbylene. Unless specifically stated otherwise in the specification, hydrocarbylene groups are optionally substituted.

The term "hydrocarbyloxy" refers to an L-O- group where L is alkyl, alkenyl, alkynyl, cycloalkyl, aryl. The hydrocarbyloxy group herein may be a hydrocarbyloxy group of 1 to 20 carbon atoms, and may also be a hydrocarbyloxy group of 1 to 15 carbon atoms, a hydrocarbyloxy group of 1 to 10 carbon atoms, a hydrocarbyloxy group of 1 to 5 carbon atoms Hydrocarbyloxy, hydrocarbyloxy of 5 to 20 carbon atoms, hydrocarbyloxy of 5 to 15 carbon atoms, or hydrocarbyloxy of 5 to 10 carbon atoms.

The term "alkyl" is intended to be a straight chain saturated hydrocarbon structure having from 1 to 20 carbon atoms. "Alkyl" is also contemplated to be a branched or cyclic hydrocarbon structure having 3 to 20 carbon atoms. For example, the alkyl group can be an alkyl group of 1 to 20 carbon atoms, an alkyl group of 1 to 10 carbon atoms, an alkyl group of 1 to 5 carbon atoms, an alkyl group of 5 to 20 carbon atoms, an alkyl group of 5 to 15 carbon atoms An alkyl group of carbon atoms or an alkyl group of 5 to 10 carbon atoms. When specifying an alkyl group having a specific carbon number, it is intended to encompass all geometric isomers having that carbon number; thus, for example, "butyl" is meant to include n-butyl, sec-butyl, isobutyl, tert-butyl and cyclobutyl; "propyl" includes n-propyl, isopropyl and cyclopropyl. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, isopentyl, neopentyl, cyclopentyl, methylcyclopentyl, ethylcyclopentyl, n-hexyl, isohexyl, cyclohexyl, n-heptyl, octyl, cyclopropyl, cyclobutyl, norbornyl Base et al. Additionally, alkyl groups can be optionally substituted.

The term "cycloalkyl" encompasses cyclic alkyl groups. The cycloalkyl group may be a cycloalkyl group of 3 to 20 carbon atoms, a cycloalkyl group of 6 to 20 carbon atoms, a cycloalkyl group of 3 to 10 carbon atoms, a cycloalkyl group of 3 to 6 carbon atoms. For example, the cycloalkyl group can be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like. Additionally, cycloalkyl groups may be optionally substituted.

The term "alkenyl" refers to a monovalent unsaturated hydrocarbon group which may be straight or branched and having at least one and usually 1, 2 or 3 carbon-carbon double bonds. Unless otherwise defined, the alkenyl group typically contains from 2 to 20 carbon atoms, for example, it may be alkenyl of 2 to 20 carbon atoms, alkenyl of 6 to 20 carbon atoms, alkenyl of 2 to 10 carbon atoms group or an alkenyl group of 2 to 6 carbon atoms. Representative alkenyl groups include, for example, vinyl, n-propenyl, isopropenyl, n-but-2-enyl, but-3-enyl, n-hex-3-enyl, and the like. Additionally, alkenyl groups may be optionally substituted.

The term "alkynyl" refers to a monovalent unsaturated hydrocarbon group which may be straight or branched and having at least one and usually one, two or three carbon-carbon triple bonds. Unless otherwise defined, the alkynyl group typically contains from 2 to 20 carbon atoms, for example, it may be alkynyl of 2 to 20 carbon atoms, alkynyl of 6 to 20 carbon atoms, alkynyl of 2 to 10 carbon atoms alkynyl or alkynyl of 2 to 6 carbon atoms. Representative alkynyl groups include, for example, ethynyl, prop-2-ynyl (n-propynyl), n-but-2-ynyl, n-hex-3-ynyl, and the like. Additionally, alkynyl groups may be optionally substituted.

The term "aryl" encompasses both monocyclic and polycyclic ring systems. A polycyclic ring may have two or more rings in which two carbons are two adjacent rings (the rings are "fused"), wherein at least one of the rings is aromatic, such as other Rings can be cycloalkyl, cycloalkenyl, aryl, heterocycle and/or heteroaryl. For example, the aryl group may be a _C6-50 aryl group, a _C6-40 aryl group, a _C6-30 aryl group, a _C6-20 aryl group, or a _C6-10 aryl group. Representative aryl groups include, for example, phenyl, methylphenyl, propylphenyl, isopropylphenyl, benzyl, and naphth-1-yl, naphth-2-yl, and the like. Additionally, aryl groups can be optionally substituted.

The term "heterocyclyl" encompasses both aromatic and non-aromatic cyclic groups. A heteroaromatic cyclic group also means a heteroaryl group. In some embodiments, the heteroaromatic ring group and the heteronon-aromatic ring group are C _1-50 heterocyclyl, C _1-40 heterocyclyl, C _1-30 heterocyclyl including at least one heteroatom , C _1-20 heterocyclyl, C _1-10 heterocyclyl, C _1-6 heterocyclyl. Examples are morpholinyl, piperidinyl, pyrrolidinyl, and the like, and cyclic ethers, such as tetrahydrofuran, tetrahydropyran, and the like. Additionally, heterocyclyl groups may be optionally substituted.

As used herein, the term "heteroaryl" encompasses monocyclic heteroaromatic groups that may include one to three heteroatoms, such as pyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole, pyrazole, pyridine, Pyrazine and pyrimidine etc. The term heteroaryl also includes polycyclic heteroaromatic systems having two or more rings in which two atoms are shared by two adjacent rings (the rings being "fused"), wherein the At least one of the rings is heteroaryl and the other rings can be cycloalkyl, cycloalkenyl, aryl, heterocycle and/or heteroaryl. For example, a heteroaryl group can be a _C6-50 heteroaryl, a _C6-40 heteroaryl, a _C6-30 heteroaryl, a _C6-20 heteroaryl, or a _C6-10 heteroaryl. Additionally, heteroaryl groups can be optionally substituted.

As used herein, the term "heteroatom" encompasses O, S, P, N, B, or isosteres thereof.

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

As used herein, the term "cyano" encompasses organics containing the organic group CN.

When the above substituents are substituted, the substituents may be selected from the group consisting of halogen, alkyl, cycloalkyl, alkenyl, aryl, and heteroaryl.

1. Electrolyte

1. Compounds of formula I

The application provides an electrolyte solution comprising a compound of formula I:

Wherein, any one of _{M 1} to M ₅ _{is M 7} -OLi group; and at least one of M ₁ to M ₅ _{is M 8} -CN group; the rest are not M ₇ -OLi group and M ₈ -CN group M ₁ to M _{5 of the} group are each independently selected from hydrogen, C _1-12 alkoxy, halogen, substituted or unsubstituted C _1-12 alkyl, substituted or unsubstituted C _2-12 alkene group, substituted or unsubstituted C _2-12 alkynyl, nitro, sulfonic acid group, aldehyde group, carboxyl group, silicon group or substituted or unsubstituted C _6-12 aryl group, wherein when substituted , the substituent is halogen; wherein M ₆ , M ₇ and M ₈ are each independently selected from C _0-5 hydrocarbylene, C _1-5 hydrocarbylene substituted by halogen.

In some embodiments, one, two or three M ₈ -CN groups _{are included in M 1} to M ₅ of the compounds of Formula I above.

In the compounds of formula I according to the present application, "C _0-5 hydrocarbylene" includes, but is not limited to: covalent bond, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec Butyl, tert-butyl, pentyl, vinyl, ethynyl, propenyl, propynyl.

In some embodiments, compounds of Formula I of the present application include at least one of compounds of Formulas 1-1 to 1-6:

wherein, R ₁ to R ₁₄ are each independently selected from hydrogen, halogen, substituted or unsubstituted C _1-12 alkoxy, substituted or unsubstituted C _1-12 alkyl, substituted or unsubstituted Substituted C _2-12 alkenyl, substituted or unsubstituted C _2-12 alkynyl, nitro, sulfonic acid, aldehyde, carboxyl, silyl or substituted or unsubstituted C _6-12 aryl group, wherein when substituted, the substituent is halogen; and n is 0-5.

_{In some embodiments, R 1} to R ₁₄ in the compounds of Formula I-1 to Formula I-6 are each independently selected from: hydrogen, substituted or unsubstituted C _1-12 alkyl, substituted or unsubstituted Substituted _C2-12 alkenyl or substituted or unsubstituted _C2-12 alkynyl.

In some embodiments, based on the total mass of the electrolyte, the content of the compound of formula I described in the present application is about 0.01% to about 10%, for example, the content of the compound of formula I may be 0.01%, 0.05%, 1.0%, 2.0%, 3.0%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 8.0%, 9.0%, 10%, or the range between any of the above contents, when adding When the concentration is lower than 0.01%, the additive cannot effectively form a film at the interface because the concentration is too low. When the concentration is higher than 10%, it will lead to serious lithium precipitation at the interface of the negative electrode. Lithium salt makes the discharge capacity of normal temperature cycle low, which affects the actual capacity of the battery.

2. Other additives

In some embodiments, the electrolyte solution of the present application further includes at least one of additive A, additive B or additive C, wherein additive A includes nitrile compounds, acid anhydride compounds, ether compounds, phosphate ester compounds, At least one of phosphoric acid ester compounds or boric acid ester compounds; Additive B comprises at least one of sulfuric ester compounds, sulfite compounds, fluorocarbonate or unsaturated carbonate; Additive C comprises sulfonic acid ester At least one of compounds, sulfones, or lithium salt additives.

In some embodiments, the electrolyte of the present application may comprise a compound of formula I above in combination with any one, two, or three of the following additives: unsaturated carbonates, eg, ethylene ethylene carbonate or vinylene carbonate ; Sulfonate compounds, such as 1,3-propane sultone; Sulfate compounds, such as vinyl sulfate; Fluorocarbonate compounds, such as fluoroethylene carbonate; Lithium salt additives, such as, Lithium difluorophosphate; nitriles such as succinonitrile and adiponitrile.

In some embodiments, based on the total mass of the electrolyte, the content of the above-mentioned Additive A and Additive B may be about 0.01% to about 10%; 1.0%, 2.0%, 3.0%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 8.0%, 9.0%, 10%, or a range between any of the above .

In some embodiments, the content of the additive C is about 0.01% to about 5% based on the total mass of the electrolyte; for example, the content of the additive C may be 0.01%, 0.05%, 1.0%, 1.5%, 2.0%, 2.5% %, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, or a range between any of the above contents.

In some embodiments, the total content of the above-mentioned Additive A, Additive B and Additive C does not exceed 20%.

(1) Additive A

In some embodiments, the nitrile compound includes at least one of the following compounds: succinonitrile, adiponitrile, 1,3,5-pentanetricarbonitrile, 1,3,6-hexanetricarbonitrile, 1,3,6-hexanetricarbonitrile 2,6-hexanetricarbonitrile, fumaric nitrile or ethylene glycol (bispropionitrile) ether.

In some embodiments, the acid anhydride compound includes at least one of the following compounds: citracic anhydride, succinic anhydride, maleic anhydride, trifluoromethyl maleic anhydride, dimethyl maleic anhydride, or propane sulfonic anhydride.

In some embodiments, the ether compound includes at least one of the following compounds: 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether or perfluorobutyl ether.

In some embodiments, the phosphate-based compound includes at least one of the following compounds: triphenyl phosphate, tris(trifluoroethyl) phosphate, or triallyl phosphate.

In some embodiments, the phosphite compound includes at least one of the following compounds: triphenyl phosphite or trimethylsilyl phosphite.

In some embodiments, the borate compound includes at least one of the following compounds: tris(hexafluoroisopropyl) borate, trimethylsilyl borate, trimethylene borate, triisopropyl borate, Tributyl borate, triethyl borate or tripropyl borate.

Additive A can form an effective passivation layer on the cathode, and the passivation layer has little effect on the SEI (solid electrolyte interface) impedance, and has good conductivity for ions and electrons. It is used in combination with the compound of formula I. Both the positive and negative interfaces have a good protective effect.

(2) Additive B

In some embodiments, the sulfate-based compound includes at least one of the following compounds: vinyl sulfate, vinyl bisulfate, vinyl methyl sulfate, vinyl ethyl sulfate, or vinyl propyl sulfate.

In some embodiments, the sulfite-based compound includes at least one of the following compounds: vinyl sulfite, vinyl methyl sulfite, vinyl ethyl sulfite, vinyl propyl sulfite, or propylene sulfite .

In some embodiments, the fluorocarbonate comprises at least one of the following compounds: fluoroethylene carbonate, methyl trifluoroethyl carbonate, or trifluoromethyl ethylene carbonate.

In some embodiments, the unsaturated carbonate includes at least one of the following compounds: ethylene ethylene carbonate or vinylene carbonate.

Additive B can form effective interface protection at the negative electrode interface, and works together with the compound of formula I to ensure that the battery has a relatively stable CEI (cathode electrolyte interface) protective layer in the initial state, and at the same time, it will continue to protect the surface layer during long-term high-temperature storage and cycling. CEI repairs, thereby effectively improving the long-term storage and cycling performance of the battery.

(3) Additive C

In some embodiments, the sulfonate compound includes at least one of the following compounds: 1,3-propane sultone, 1,4-butane sultone, 2,4-butane sultone, propylene yl-1,3-sultone, methylene methanedisulfonate or chain bissulfonate.

In some embodiments, the sulfone compound includes at least one of the following compounds: sulfolane, sulfolane, or 3-sulfolene.

In some embodiments, the lithium salt additive includes at least one of the following compounds: 4,5-dicyano-2-(trifluoromethyl)imidazolium lithium, lithium difluorophosphate, lithium tetrafluoroborate, bisfluorolithium Lithium sulfonimide, lithium bistrifluorosulfonimide, lithium oxalate borate, or lithium bisfluorooxalate borate.

The additive C and the compound of formula I work together to form an effective passivation layer at the interface of the positive and negative electrodes, and the redox activity of the additive is low. Repair with SEI, thereby effectively improving the long-term storage and cycling performance of the battery. 3. Other

In some embodiments, the electrolyte solution of the present application further comprises an organic solvent selected from at least one of cyclic carbonate, chain carbonate, carboxylate or sulfone solvents.

In some embodiments, the cyclic carbonate is selected from at least one of ethylene carbonate or propylene carbonate; the chain carbonate is selected from dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and propyl methyl carbonate Or at least one in ethyl propyl carbonate; Carboxylic acid ester is selected from at least one in ethyl acetate, ethyl propionate, propyl propionate, propyl acetate, ethyl difluoroacetate or difluoroethyl acetate ; Sulfone solvent is selected from sulfolane, n-butyl sulfone, sulfolane, cyclohexyl sulfone, 2,4-dimethyl sulfolane, 3-methyl-3-sulfolane, n-butyl sulfoxide, di-n-octane At least one of the sulfone tetramethyl sulfoxide.

2. Electrochemical device

The present application also provides an electrochemical device comprising the electrolyte according to the present application.

The electrochemical device of the present application includes 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 is a lithium-ion battery.

positive electrode

The electrochemical device according to the present application may further include a positive electrode including a current collector and a positive electrode active material layer disposed on the current collector. The positive electrode active material contains at least one element selected from Al, Zr, or Mg. For example, the positive electrode active material may include Al and Zr, Al and Mg, Zr and Mg, or a combination of Al, Zr and Mg.

In some embodiments, the Al content a is less than 1% based on the total mass of the positive active material, for example, the Al content a may be less than 0.9%, less than 0.8%, less than 0.7%, less than 0.6%, less than 0.5%, or A range between any two of the above numerical values or between any of the above numerical values and zero.

In some embodiments, the Zr content b is less than 1% based on the total mass of the positive active material, for example, the Zr content b may be less than 0.9%, less than 0.8%, less than 0.7%, less than 0.6%, less than 0.5%, or A range between any two of the above numerical values or between any of the above numerical values and zero.

In some embodiments, the Mg content c is less than 0.5% based on the total mass of the positive active material, for example, the Mg content c may be less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, less than 0.1%, or A range between any two of the above numerical values or between any of the above numerical values and zero.

In some embodiments, the positive electrode material includes Al and Mg, and the content thereof satisfies the following condition: 0.005<a/c<500. For example, the ratio of a/c can be 0.004, 0.01, 0.1, 1, 10, 20, 50, 80, 100, 120, 140, 180, 200, 230, 250, 270, 300, 350, 400, 420, 450 , 499, etc. The content of Al and Mg within this range can more effectively improve the overall performance of the battery.

In some embodiments, the positive active material includes a compound that reversibly intercalates and deintercalates lithium ions. In some embodiments, the positive electrode active material may include a composite oxide containing lithium and at least one element selected from cobalt, manganese, and nickel. In still other embodiments, the positive active material is selected from lithium cobalt oxide (LiCoO ₂ ), lithium nickel manganese cobalt ternary material, lithium manganate (LiMn ₂ O ₄ ), lithium nickel manganate (LiNi _0.5 Mn _1.5 O ₄ ) or at least one of lithium iron phosphate (LiFePO _{4 ).}

In some embodiments, the cathode active material layer may have a coating on the surface, or may be mixed with another compound having a coating.

In some embodiments, the coating may comprise an oxide from a coating element, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, or a coating element At least one coating element compound selected from hydroxycarbonate.

The compound used for the coating can be amorphous or crystalline.

In some embodiments, the coating elements contained in the coating may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, F or their at least one of the mixtures.

The coating can be applied by any method as long as the method does not adversely affect the performance of the positive electrode active material. For example, the method may include any coating method well known to those of ordinary skill in the art, such as spraying, dipping, and the like.

In some embodiments, the positive active material layer further includes a binder, and optionally a conductive material.

The binder can improve the bonding of the positive electrode active material particles to each other, and can also improve the bonding of the positive electrode active material and the current collector. In some embodiments, non-limiting examples of binders include polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-containing Oxygen polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (esterified) styrene-butadiene rubber, epoxy resin, Nylon etc.

The positive electrode active material layer may further include a conductive material, thereby imparting conductivity to the electrode. The conductive material may include any conductive material as long as it does not cause unwanted chemical changes. In some embodiments, non-limiting examples of conductive materials include carbon-based materials (eg, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, etc.), metal-based materials (eg, metal powders) , metal fibers, etc., including, for example, copper, nickel, aluminum, silver, etc.), conductive polymers (eg, polyphenylene derivatives), and mixtures thereof.

In some embodiments, the current collector for the positive electrode of the secondary battery according to the present application may be aluminum (Al), but is not limited thereto.

negative electrode

The electrochemical device according to the present application may further include a negative electrode including a current collector and a negative electrode active material layer disposed on the current collector. The specific types of negative electrode active materials are not specifically limited, and can be selected according to requirements.

Specifically, in some embodiments, the negative electrode active material is selected from natural graphite, artificial graphite, mesophase microcarbon spheres (abbreviated as MCMB), hard carbon, soft carbon, silicon, silicon-carbon composite, Li-Sn At least one of an alloy, a Li-Sn-O alloy, Sn, SnO, SnO ₂ , a spinel-structured lithiated TiO ₂ -Li ₄ Ti ₅ O ₁₂ or a Li-Al alloy.

In some embodiments, non-limiting examples of carbon materials include crystalline carbon, amorphous carbon, and mixtures thereof. Crystalline carbon can be amorphous or flake-shaped, platelet-shaped, spherical or fibrous natural graphite or artificial graphite. The amorphous carbon can be soft carbon, hard carbon, mesophase pitch carbide, calcined coke, and the like.

In some embodiments, the anode active material layer may include a binder, and optionally a conductive material.

The binder can improve the bonding of the negative electrode active material particles to each other and the bonding of the negative electrode active material to the current collector. In some embodiments, non-limiting examples of binders include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyfluoro Ethylene, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene Rubber, epoxy resin, nylon, etc.

The anode active material layer may include a conductive material, thereby imparting conductivity to the electrode. The conductive material may include any conductive material as long as it does not cause unwanted chemical changes. In some embodiments, non-limiting examples of conductive materials include carbon-based materials (eg, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, etc.), metal-based materials (eg, metal powders) , metal fibers, etc., such as copper, nickel, aluminum, silver, etc.), conductive polymers (eg, polyphenylene derivatives), and mixtures thereof.

In some embodiments, the current collector for the negative electrodes described herein can be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, conductive metal clad polymer substrates, and combinations thereof .

isolation film

In some embodiments, the electrochemical device of the present application is provided with a separator between the positive electrode and the negative electrode to prevent short circuits. The material and shape of the separator used in the electrochemical device of the present application are not particularly limited. In some embodiments, the separator includes a polymer or inorganic or the like formed from a material that is stable to the electrolyte of the present application.

For example, the release film may include a substrate layer and a surface treatment layer.

In some embodiments, the substrate layer is a non-woven fabric, film or composite film with a porous structure, and the material of the substrate layer is selected from polyethylene, polypropylene, polyethylene terephthalate or polyimide at least one of them. Specifically, in some embodiments, a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene non-woven fabric, a polyethylene non-woven fabric or a polypropylene-polyethylene-polypropylene porous composite membrane can be selected.

In some embodiments, at least one surface of the substrate layer is provided with a surface treatment layer, and the surface treatment layer may be a polymer layer or an inorganic layer, or a layer formed by mixing polymers and inorganic substances.

In some embodiments, the inorganic layer includes inorganic particles and a binder. In some embodiments, the inorganic particles are selected from the group consisting of aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide , at least one of boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide or barium sulfate. In some embodiments, the binder is selected from the group consisting of polyvinylidene fluoride, copolymers of vinylidene fluoride-hexafluoropropylene, polyamides, polyacrylonitrile, polyacrylates, polyacrylic acids, polyacrylates, polyethylene pyrrolidines At least one of ketone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene or polyhexafluoropropylene.

The polymer layer contains a polymer. In some embodiments, the material of the polymer is selected from polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride or poly(vinylidene fluoride) At least one of fluoroethylene-hexafluoropropylene).

3. Electronic devices

The electrochemical device according to the present application is suitable for electronic equipment in various fields. The use of the electrochemical device of the present application is not particularly limited, and it can be used for any use known in the art. In one embodiment, the electrochemical devices of the present application may be used in, but are not limited to, the following electronic devices: notebook computers, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers , Headphones, VCRs, LCD TVs, Portable Cleaners, Portable CD Players, Mini Discs, Transceivers, Electronic Notepads, Calculators, Memory Cards, Portable Recorders, Radios, Backup Power, Motors, Cars, Motorcycles Cars, power-assisted bicycles, bicycles, lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.

The present application achieves the following unexpected technical effects: during the chemical formation process of the compound of formula I provided by the present application, very stable CEI and SEI protective films are easily formed on the surfaces of the positive and negative electrodes. The protective film is fully fused with the substrate, and on the negative electrode, the protective film can provide a complexation point with lithium ions, so that rapid ion transport can be performed, and at the same time, the large amount of electrolyte deposition on the negative electrode due to irreversible reduction can be effectively suppressed. On the positive electrode, the protective film can reduce the reaction between the positive electrode and the electrolyte, while inhibiting the dissolution of metal ions, ultimately improving the high-temperature storage performance of electrochemical devices (eg, lithium-ion batteries). In addition, in the electrochemical device of the present application, by controlling the content of doping elements Al, Zr and Mg in the positive electrode material, and adding the compound of formula I on this basis, the film-forming effect of the electrolyte solution of the present application on the positive and negative electrodes can be improved. Good, so that the formed protective film has more excellent high temperature stability, thereby further improving the high temperature storage performance of the electrochemical device (eg, lithium ion battery) of the present application.

Fourth, the embodiment

The present application will be further described below with reference to the embodiments. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application.

Example

1. Preparation method

(1) Preparation of electrolyte

In a drying room, ethylene carbonate, propylene carbonate and diethyl carbonate are uniformly mixed in a mass ratio of 1:1:1 to obtain a non-aqueous organic solvent. _{1 mol/L lithium hexafluorophosphate (LiPF 6} ) was added to the non-aqueous organic solvent to obtain a base electrolyte. In the base electrolyte, other additives were added according to the amounts and types provided in the table below to obtain the electrolytes of the respective examples and comparative examples.

(2) Positive electrode preparation

The positive electrode active material, the binder polyvinylidene fluoride (PVDF) and the conductive agent Super-P were dissolved in N-methylpyrrolidone (NMP) in a mass ratio of 96:2:2 and mixed uniformly to prepare a positive electrode slurry. The positive electrode slurry was uniformly coated on the positive electrode current collector aluminum foil with a thickness of 12 μm, and the positive electrode active material layer was obtained by baking at 120 °C for 1 h, and then the positive electrode was obtained by compacting, slitting and welding tabs.

(3) Preparation of negative electrode

The negative electrode active material graphite powder, silicon oxide powder, sodium carboxymethyl cellulose thickener (CMC) and binder styrene-butadiene rubber are dissolved in water in a mass ratio of 81:15:2:2, fully mixed and stirred to obtain a negative electrode slurry The negative electrode slurry was uniformly coated on the negative electrode current collector copper foil with a thickness of 12 μm, baked at 120 °C for 1 h, and then compacted to obtain the negative electrode active material layer, and then the electrode tabs were cut and welded to obtain the negative electrode.

(4) Preparation of batteries

A 12 μm polypropylene film was used as the separator. The positive electrode, the separator and the negative electrode are stacked in order so that the separator is in the middle of the positive and negative electrodes for isolation, and then rolled into a square bare cell. The bare cell is put into an aluminum foil packaging bag, baked at 80°C to remove water, and then injected with the corresponding electrolyte.

2. Test method

The performance of the lithium ion batteries prepared in the Examples and Comparative Examples was tested using the following methods.

(1) High temperature storage test

Before storage, charge to 3.65V with a constant current of 0.5C, then test the thickness of the battery with a thickness tester to get D1, continue to charge at 0.5C to 4.2V, and charge at a constant voltage to a current of 0.05C, then place the lithium-ion battery at 60 Store in a high temperature box for 30 days, and measure the thickness of the battery again after cooling down to obtain D2:

Battery thickness growth rate = (D2-D1)÷D1×100%

(2) 45℃ cycle test:

Place the battery in a 45°C oven, charge it to 4.2V at a constant current of 0.5C, charge it at a constant voltage to a current of 0.05C, discharge it to 2.8V at 0.5C, and cycle for 400 cycles:

Battery capacity retention rate = 400th cycle discharge capacity ÷ first cycle discharge capacity × 100%

3. Test results

Examples 1 to 23 and Comparative Example 1

The positive electrode materials used in Examples 1 to 23 and Comparative Example 1 are ternary nickel-cobalt-manganese (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ , NCM811), wherein the doping amount of Al is 0.15%, and the doping amount of Zr is 0.007 %, and the doping amount of Mg is 0.1%. The specific test results are shown in Table 1 below.

Table 1. Test results for Examples 1 to 23 and Comparative Example 1

Examples 1 to 23 in the above table added the compound of formula I with different contents and types, and comparative example 1 did not add the compound of formula I. As can be seen from the data in the above table, when the compound of formula I according to the present application is not added to the electrolyte, the thickness growth rate of the battery at high temperature storage is 45%, and after the compound of formula I is added, the thickness of the battery increases significantly. The reason for the improvement is due to the fact that the compound of formula I of the present application can produce a stable protective film on the surfaces of the positive and negative electrodes during the formation process, thereby reducing the further reaction between the positive and negative electrodes and the electrolyte during the high-temperature storage process of the battery, and finally reducing storage. The purpose of flatulence and improving high temperature storage performance.

In Examples 1 to 7, different contents of Compound 1 were respectively added to the electrolyte. From the test results of Examples 1 to 7, it can be seen that when the amount of the compound of formula I is in the range of 0.01 wt % to 10 wt %, it can ensure complete dissolution, thereby providing a good film-forming effect and significantly improving electrochemical performance. High temperature storage performance of the device. When the amount of the compound of formula I exceeds the scope of the present application, the improvement effect is not obvious. On the one hand, when the amount of the compound of formula I is too high, it cannot be completely dissolved, and does not play a protective role in film formation; film, weakening the protection of positive and negative electrodes, resulting in insignificant improvement in high-temperature storage performance.

It can be seen from the test results of Examples 17 to 23 that the combined use of different compounds of formula I can also improve the high temperature storage performance of the electrochemical device.

Examples 24 to 52

Embodiments 24 to 52 illustrate examples of using the compound of formula I of the present application in combination with other additives, wherein the positive electrode material used is ternary nickel cobalt manganese (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ , NCM811), wherein Al The doping amount of Zr is 0.15%, the doping amount of Zr is 0.007%, and the doping amount of Mg is 0.1%. The specific test results are shown in Table 2 below.

Table 2. Test Results for Examples 24 to 52

Examples 24 to 52 demonstrate that the compounds of formula I of the present application can be used in combination with other types of additives to further improve the high temperature storage and cycling performance of electrochemical devices.

For example, it can be seen from the test results in the above table that on the basis of the compound of formula I, further improvement can be achieved by adding one, two or three of the following compounds: VC (vinylene carbonate) ester), PS (1,3-propane sultone), DTD (vinyl sulfate), FEC (fluoroethylene carbonate), Li ₂ PO ₂ F ₂ (lithium difluorophosphate), ADN (adiponitrile) , SN (succinonitrile), HTCN (1,3,6-hexanetricarbonitrile) or acid anhydride, these combinations can achieve more excellent high temperature storage performance and/or cycle performance.

Examples 53 to 69

The positive electrode materials used in Examples 53 to 69 were ternary nickel-cobalt-manganese (LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , NCM523), and the doping amounts of each element were shown in Table 3 below.

Table 3. Test Results for Examples 53 to 69

From the test results of Examples 53 to 69 in the above table, it can be seen that when the doping amount of Al in the positive electrode material is a<1%, the doping amount b of Zr is less than 1%, and the doping amount of Mg is c<0.5% , the battery has good high temperature storage performance and cycle performance.

Reference throughout the specification to "some embodiments," "some embodiments," "one embodiment," "another example," "example," "specific example," or "partial example" means that At least one embodiment or example in this application incorporates a particular feature, structure, material or characteristic described in the embodiment or example. Thus, descriptions such as: "in some embodiments", "in an embodiment", "in one embodiment", "in another example", "in an example", appearing in various places throughout the specification "in", "in a particular example" or "by way of example", which are not necessarily referring to the same embodiment or example in this application. Furthermore, the particular features, structures, materials or characteristics herein may be combined in any suitable manner in one or more embodiments or examples.

Although illustrative embodiments have been shown and described, it should be understood by those skilled in the art that the above-described embodiments are not to be construed as limitations of the application, and changes may be made in the embodiments without departing from the spirit, principles and scope of the application , alternatives and modifications.

Claims

An electrolyte comprising a compound of formula I:

Wherein, any one of M 1 to M 5 is M 7 -OLi group; and at least one of M 1 to M 5 is M 8 -CN group; the rest are not M 7 -OLi group and M 8 -CN group M 1 to M 5 of the group are each independently selected from hydrogen, substituted or unsubstituted C 1-12 alkoxy, halogen, substituted or unsubstituted C 1-12 alkyl, substituted or unsubstituted Substituted C 2-12 alkenyl, substituted or unsubstituted C 2-12 alkynyl, nitro, sulfonic acid, aldehyde, carboxyl, silyl or substituted or unsubstituted C 6-12 aryl group, wherein when substituted, the substituent is halogen;

wherein M 6 , M 7 and M 8 are each independently selected from C 0-5 hydrocarbylene, C 1-5 hydrocarbylene substituted by halogen.
The electrolyte of claim 1, wherein the compound of formula (I) comprises at least one of the compounds of formula I-1 to formula I-6:

wherein, R 1 to R 14 are each independently selected from hydrogen, halogen, substituted or unsubstituted C 1-12 alkoxy, substituted or unsubstituted C 1-12 alkyl, substituted or unsubstituted Substituted C 2-12 alkenyl, substituted or unsubstituted C 2-12 alkynyl, nitro, sulfonic acid, aldehyde, carboxyl, silyl or substituted or unsubstituted C 6-12 Aryl wherein, when substituted, the substituent is halogen; and n is an integer from 0-5.
The electrolyte of claim 1, wherein the compound of formula I comprises at least one of the following compounds:
The electrolyte according to claim 1, wherein the content of the compound of formula I is 0.01% to 10% based on the total mass of the electrolyte.
The electrolyte according to any one of claims 1-4, further comprising at least one of additive A, additive B or additive C, wherein the additive A comprises nitrile compounds, acid anhydride compounds, ethers At least one of compounds, phosphate compounds, phosphite compounds or borate compounds; the additive B comprises sulfate compounds, sulfite compounds, fluorocarbonates or unsaturated carbonates At least one of ; the additive C comprises at least one of sulfonate compounds, sulfone compounds or lithium salt additives; and

Based on the total mass of the electrolyte, the content of the additive A is 0.01% to 10%; the content of the additive B is 0.01% to 10%; the content of the additive C is 0.01% to 5%.
The electrolyte according to claim 5, wherein:

The nitrile compound includes at least one of the following compounds: succinonitrile, adiponitrile, 1,3,5-pentanetricarbonitrile, 1,3,6-hexanetricarbonitrile, 1,2,6- Hexane trimonitrile, fumaric nitrile or ethylene glycol (bispropionitrile) ether;

The acid anhydride compounds include at least one of the following compounds: citracic anhydride, succinic anhydride, maleic anhydride, trifluoromethyl maleic anhydride, dimethyl maleic anhydride or propane sulfonic anhydride;

The ether compound includes at least one of the following compounds: 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether or perfluorobutyl ether;

The phosphate compound includes at least one of the following compounds: triphenyl phosphate, tris(trifluoroethyl) phosphate or triallyl phosphate;

The phosphite compounds include at least one of the following compounds: triphenyl phosphite or trimethylsilyl phosphite;

The borate compound includes at least one of the following compounds: tris(hexafluoroisopropyl) borate, trimethylsilyl borate, trimethylene borate, triisopropyl borate, tributyl borate , triethyl borate or tripropyl borate;

The sulfate-based compound includes at least one of the following compounds: vinyl sulfate, vinyl bisulfate, vinyl methyl sulfate, vinyl ethyl sulfate or vinyl propyl sulfate;

The sulfite compounds include at least one of the following compounds: vinyl sulfite, vinyl methyl sulfite, ethyl vinyl sulfite, propyl vinyl sulfite or propylene sulfite;

The fluorocarbonate includes at least one of the following compounds: fluoroethylene carbonate, methyl trifluoroethyl carbonate or trifluoromethyl ethylene carbonate;

The unsaturated carbonate includes at least one of the following compounds: ethylene ethylene carbonate or vinylene carbonate;

The sulfonate compound includes at least one of the following compounds: 1,3-propane sultone, 1,4-butane sultone, 2,4-butane sultone, propenyl-1, 3-Sultone, methylene methanedisulfonate or chain bissulfonate;

The sulfone compounds include at least one of the following compounds: sulfolane, sulfolane or 3-sulfolane;

The lithium salt additive includes at least one of the following compounds: 4,5-dicyano-2-(trifluoromethyl)imidazolium lithium, lithium difluorophosphate, lithium tetrafluoroborate, bisfluorosulfonimide Lithium, Lithium Bistrifluorosulfonimide, Lithium oxalate borate or Lithium bisfluorooxalate borate.
An electrochemical device comprising a positive electrode and the electrolyte of any one of claims 1-6, the positive electrode comprising a positive electrode active material.
The electrochemical device according to claim 7, wherein the positive electrode active material contains at least one element selected from the group consisting of Al, Zr, or Mg.
The electrochemical device according to claim 8, wherein the content a of the Al is less than 1%, the content b of the Zr is less than 1%, and the content c of the Mg is less than 0.5% based on the total mass of the positive electrode active material .
The electrochemical device according to claim 9, wherein the positive electrode material contains Al and Mg, and the content thereof satisfies the following condition: 0.005<a/c<500.
An electronic device comprising the electrochemical device of any one of claims 7-10.