Electrolyte solution, and electrochemical device and electronic device using same
阅读说明：本技术 电解液及使用其的电化学装置和电子装置 (Electrolyte solution, and electrochemical device and electronic device using same ) 是由 管明明 刘建禹 熊亚丽 郑建明 于 2020-03-31 设计创作，主要内容包括：本申请涉及一种电解液及使用其的电化学装置和电子装置。具体而言,本申请提供一种电解液,其包括离子液体,所述离子液体包括至少两种离子液体组分。本申请的包含特定离子液体组分组合的电解液有助于改善电化学装置的动力学性能、存储性能和安全性能。(The present application relates to an electrolyte solution, and an electrochemical device and an electronic device using the same. Specifically, the present application provides an electrolyte comprising an ionic liquid comprising at least two ionic liquid components. The electrolyte comprising a specific combination of ionic liquid components of the present application contributes to the improvement of the kinetic properties, storage properties and safety properties of the electrochemical device.)
1. An electrolyte comprising an ionic liquid, wherein the ionic liquid comprises a first ionic liquid component and a second ionic liquid component,
the first ionic liquid component comprises a cation of formula I:
wherein:
R1selected from the group consisting of substituted or unsubstituted imidazolium cations, substituted or unsubstituted pyrrol cations, substituted or unsubstituted pyridinium cations, substituted or unsubstituted piperidinium cations, substituted or unsubstituted ammonium cations, and substituted or unsubstituted phosphonium cations;
R2selected from covalent bond, substituted or unsubstituted C1-C8Alkylene or substituted or unsubstituted C1-C8Alkenylene, substituted or unsubstituted C6-C12An arylene group;
1≤x≤6；
wherein when substituted, the substituents are selected from halogen, C1-C3Alkyl radical, C2-C4At least one of alkenyl or-CN;
the second ionic liquid component comprises a cation of formula II:
wherein:
R3selected from the group consisting of substituted or unsubstituted imidazolium cations, substituted or unsubstituted pyrrol cations, substituted or unsubstituted pyridinium cations, substituted or unsubstituted piperidinium cations, substituted or unsubstituted phosphonium cations, and substituted or unsubstituted ammonium cations;
R4selected from substituted or unsubstituted C1-C8Alkylene, substituted or unsubstituted C1-C8Alkenylene or substituted or unsubstituted C6-C12An arylene group;
1≤y≤6；
wherein when substituted, the substituents are selected from halogen, C1-C3Alkyl radical, C2-C4At least one of an alkenyl group, -CN, or sulfone group.
2. The electrolyte of claim 1, wherein the anion of the first ionic liquid component and the anion of the second ionic liquid component are each independently selected from at least one of hexafluorophosphate, bistrifluoromethylsulfonate, bistfluoromethylsulfonate, bisoxalato borate, difluorooxalato borate, or tetrafluoroborate.
3. The electrolyte of claim 1, wherein the cation in the first ionic liquid component comprises At least one of (a) and (b),
wherein:
R11、R12、R14、R15、R17、R18、R19、R20and R21Each independently selected from substituted or unsubstituted C1-C8Alkyl or substituted or unsubstituted C6-C12An aryl group;
R13and R16Each independently selected from substituted or unsubstituted C1-C8Alkylene or substituted or unsubstituted C6-C12An arylene group;
wherein when substituted, the substituents are selected from halogen, -CN, C1-C3Alkyl radical, C2-C4At least one of an alkenyl group or a sulfone group.
4. The electrolyte of claim 1, wherein the cation in the second ionic liquid component comprises At least one of (a) and (b),
wherein:
R22、R23、R25、R26、R27and R28Each independently selected from substituted or unsubstituted C1-C8Alkyl, substituted or unsubstituted C6-C12An aryl group;
R24selected from substituted or unsubstituted C1-C8Alkylene or substituted or unsubstituted C6-C12An arylene group;
wherein when substituted, the substituents are selected from halogen, -CN, C1-C3Alkyl radical, C2-C4At least one of an alkenyl group or a sulfone group.
5. The electrolyte of claim 1, wherein a weight ratio of the first ionic liquid component to the second ionic liquid component is from 1:99 to 99:1, based on a total weight of the electrolyte.
6. The electrolyte of claim 1, wherein the ionic liquid further comprises a third ionic liquid component comprising a cation represented by formula III:
wherein:
R29and R30Each independently selected from a fluorine atom, a fluorinated hydrocarbon, a fluorinated aromatic hydrocarbon or a sulfone group; and is
1≤z≤6；
And the anion in the third ionic liquid component is selected from at least one of hexafluorophosphate, bis-trifluoromethylsulfonate, bis-fluoromethylsulfonate, bis-oxalato borate, difluoro-oxalato borate or tetrafluoroborate.
7. The electrolyte of claim 1, wherein the electrolyte further comprises a compound having a nitrile group, the compound having a nitrile group comprising at least one of a compound of formula IV-a or a compound of formula IV-B:
wherein:
R31、R32、R34、R35、R36and R37Each independently selected from-OR0-, substituted or unsubstituted C1-C10Alkylene, substituted or unsubstituted C2-C10Alkenylene or sulfonyl;
R0selected from substituted or unsubstituted C1-C5Alkylene, substituted or unsubstituted C2-C6An alkenylene group;
R33selected from hydrogen, substituted or unsubstituted C1-C10Alkyl, substituted or unsubstituted C2-C10An alkenyl group or a sulfonyl group,
wherein when substituted, the substituents are selected from halogen, C1-C3Alkyl radical, C2-C4Alkenyl, -CN, sulfonyl or ester group.
8. The electrolyte of claim 7, wherein the compound having a nitrile group comprises
At least one of (1).
9. The electrolyte of claim 1, wherein the electrolyte further comprises a compound of formula V:
wherein:
R38and R39Each independently selected from substituted or unsubstituted C1-C10Alkyl, substituted or unsubstituted C2-C10Alkenyl or substituted or unsubstituted C2-C10Alkynyl and
when substituted, the substituents are selected from halogen, C1-C3At least one of fluoroalkyl group, sulfone group, -CN or ether group;
provided that R is38And R39At least one of which contains fluorine atoms.
10. The electrolyte of claim 9, wherein the compound of formula V is selected from
At least one of (1).
11. An electrochemical device comprising a positive electrode, a negative electrode and the electrolyte of any one of claims 1-10.
12. An electronic device comprising the electrochemical device of claim 11.
Technical Field
The application relates to the field of energy storage, in particular to an electrolyte and an electrochemical device and an electronic device using the same.
Background
Electrochemical devices (such as lithium ion batteries) are widely applied to the fields of wearable devices, smart phones, unmanned aerial vehicles, even electric vehicles and the like due to the advantages of environmental friendliness, high working voltage, large specific capacity, long cycle life and the like, and become the novel green chemical power source with the most development potential in the world today. The high frequency and high power operating conditions make the lithium ion battery have higher requirements on safety performance (thermal abuse, mechanical abuse, etc.) and service life.
When safety is improved by adding a flame retardant to an electrolyte, the kinetic performance and storage performance of a lithium ion battery are deteriorated due to the high viscosity of the flame retardant and instability to a negative electrode.
In view of the foregoing, there is a need for an improved electrolyte and an electrochemical device and an electronic device using the same.
Disclosure of Invention
The present application attempts to solve at least one of the problems existing in the related art to at least some extent by providing an electrolyte and an electrochemical device and an electronic device using the same.
According to one aspect of the present application, there is provided an electrolyte comprising an ionic liquid, wherein the ionic liquid comprises a first ionic liquid component and a second ionic liquid component,
the first ionic liquid component comprises a cation of formula I:
wherein:
R1selected from the group consisting of substituted or unsubstituted imidazolium cations, substituted or unsubstituted pyrrol cations, substituted or unsubstituted pyridinium cations, substituted or unsubstituted piperidinium cations, substituted or unsubstituted ammonium cations, and substituted or unsubstituted phosphonium cations;
R2selected from covalent bond, substituted or unsubstituted C1-C8Alkylene or substituted or unsubstituted C1-C8Alkenylene, substituted or unsubstituted C6-C12An arylene group;
1≤x≤6；
wherein when substituted, the substituents are selected from halogen, C1-C3Alkyl radical, C2-C4At least one of alkenyl or-CN;
the second ionic liquid component comprises a cation of formula II:
wherein:
R3selected from substituted or unsubstituted imidazolium cations, substitutedOr an unsubstituted pyrrole cation, a substituted or unsubstituted pyridine cation, a substituted or unsubstituted piperidine cation, a substituted or unsubstituted phosphonium cation, or a substituted or unsubstituted ammonium cation;
R4selected from substituted or unsubstituted C1-C8Alkylene, substituted or unsubstituted C1-C8Alkenylene or substituted or unsubstituted C6-C12An arylene group;
1≤y≤6；
wherein when substituted, the substituents are selected from halogen, C1-C3Alkyl radical, C2-C4At least one of an alkenyl group, -CN, or sulfone group.
According to embodiments herein, the anion in the first ionic liquid component and the anion in the second ionic liquid component are each independently selected from hexafluorophosphate (PF)6 -) Bis (trifluoromethyl) sulfonate (TFSI)-) bis-Fluoromethylsulfonate (FSI)-) Bis (oxalato) borate (BOB)-) Difluoro oxalato borate (DFOB)-) Or tetrafluoroborate (BF)4 -) At least one of (1).
According to embodiments of the present application, the cation in the first ionic liquid component comprises At least one of (a) and (b),
wherein:
R11、R12、R14、R15、R17、R18、R19、R20and R21Each independently selected from substituted or unsubstituted C1-C8Alkyl or substituted or unsubstituted C6-C12An aryl group;
R13and R16Each independently selected from substituted or unsubstituted C1-C8Alkylene or substituted or unsubstituted C6-C12An arylene group;
wherein when substituted, the substituents are selected from halogen, -CN, C1-C3Alkyl radical, C2-C4At least one of an alkenyl group or a sulfone group.
According to embodiments herein, the first ionic liquid component comprises at least one of the following compounds:
according to embodiments of the present application, the cation in the second ionic liquid component comprises At least one of (a) and (b),
wherein:
R22、R23、R25、R26、R27and R28Each independently selected from substituted or unsubstituted C1-C8Alkyl, substituted or unsubstituted C6-C12An aryl group;
R24selected from substituted or unsubstituted C1-C8Alkylene or substituted or unsubstituted C6-C12An arylene group;
wherein when substituted, the substituents are selected from halogen, -CN, C1-C3Alkyl radical, C2-C4At least one of an alkenyl group or a sulfone group.
According to embodiments herein, the second ionic liquid component comprises at least one of the following compounds:
according to embodiments herein, the ionic liquid further comprises a third ionic liquid component having a fluoroalkylene group, the third ionic liquid component comprising a cation of formula III:
wherein:
R29and R30Each independently selected from a fluorine atom, a fluorinated hydrocarbon, a fluorinated aromatic hydrocarbon or a sulfone group; and is
2≤z≤6；
And the anion in the third ionic liquid component is selected from at least one of hexafluorophosphate, bis-trifluoromethylsulfonate, bis-fluoromethylsulfonate, bis-oxalato borate, difluoro-oxalato borate or tetrafluoroborate.
According to embodiments herein, the third ionic liquid component comprises at least one of the following compounds:
according to an embodiment of the present application, the content of the ionic liquid is 0.01 wt% to 25 wt% based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 0.05 wt% to 20 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 0.08 wt% to 18 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 0.1 wt% to 15 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 0.5 wt% to 12 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 1 wt% to 10 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 1 wt% to 8 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 2 wt% to 5 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 0.01, 0.03, 0.05, 0.1, 0.5, 1,2, 5, 8, 10, 12, 15, 18, 20, 22, or 25 wt% based on the total weight of the electrolyte.
According to an embodiment of the present application, the content of the first ionic liquid component is 0.01 wt% to 10 wt% based on the total weight of the electrolyte. In some embodiments, the first ionic liquid component is present in an amount of 0.05 wt% to 8 wt%, based on the total weight of the electrolyte. In some embodiments, the first ionic liquid component is present in an amount of 0.1 wt% to 7 wt%, based on the total weight of the electrolyte. In some embodiments, the first ionic liquid component is present in an amount of 0.5 wt% to 5 wt%, based on the total weight of the electrolyte. In some embodiments, the first ionic liquid component is present in an amount of 0.5 wt% to 4 wt%, based on the total weight of the electrolyte. In some embodiments, the first ionic liquid component is present in an amount of 0.01, 0.03, 0.05, 0.1, 0.5, 1,2, 5, 8, or 10 wt%, based on the total weight of the electrolyte.
According to an embodiment of the present application, the content of the second ionic liquid component is 0.01 wt% to 10 wt% based on the total weight of the electrolyte. In some embodiments, the second ionic liquid component is present in an amount of 0.05 wt% to 8 wt%, based on the total weight of the electrolyte. In some embodiments, the second ionic liquid component is present in an amount of 0.1 wt% to 7 wt%, based on the total weight of the electrolyte. In some embodiments, the second ionic liquid component is present in an amount of 0.5 wt% to 5 wt%, based on the total weight of the electrolyte. In some embodiments, the second ionic liquid component is present in an amount of 0.5 wt% to 4 wt%, based on the total weight of the electrolyte. In some embodiments, the second ionic liquid component is present in an amount of 0.01, 0.03, 0.05, 0.1, 0.5, 1,2, 5, 8, or 10 wt%, based on the total weight of the electrolyte.
According to an embodiment of the present application, the weight ratio of the first ionic liquid component to the second ionic liquid component is from 1:99 to 99:1, based on the total weight of the electrolyte. In some embodiments, the weight ratio of the first ionic liquid component to the second ionic liquid component is from 10:90 to 90:10, based on the total weight of the electrolyte. In some embodiments, the weight ratio of the first ionic liquid component to the second ionic liquid component is from 20:80 to 80:20, based on the total weight of the electrolyte. In some embodiments, the weight ratio of the first ionic liquid component to the second ionic liquid component is from 30:70 to 70:30, based on the total weight of the electrolyte. In some embodiments, the weight ratio of the first ionic liquid component to the second ionic liquid component is from 40:60 to 60:40, based on the total weight of the electrolyte. The weight ratio of the first ionic liquid component to the second ionic liquid component is 1:99, 5:95, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, 95:5, or 99:1, based on the total weight of the electrolyte.
According to an embodiment of the present application, the content of the third ionic liquid component is 0.01 wt% to 20 wt% based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 0.05 wt% to 18 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 0.1 wt% to 15 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 0.5 wt% to 12 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 0.5 wt% to 10 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 1 wt% to 8 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 1 wt% to 5 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 0.01, 0.03, 0.05, 0.1, 0.5, 1,2, 5, 8, 10, 12, 15, 18, or 20 wt% based on the total weight of the electrolyte.
According to an embodiment of the application, the electrolyte further comprises a compound having a nitrile group, the compound having a nitrile group comprising at least one of a compound of formula IV-a or a compound of formula IV-B:
wherein:
R31、R32、R34、R35、R36and R37Each independently selected from-OR0-, substituted or unsubstituted C1-C10Alkylene, substituted or unsubstituted C2-C10Alkenylene or sulfonyl;
R0selected from substituted or unsubstituted C1-C5Alkylene, substituted or unsubstituted C2-C6An alkenylene group;
R33selected from hydrogen, substituted or unsubstituted C1-C10Alkyl, substituted or unsubstituted C2-C10Alkenyl or sulfonyl, wherein when substituted, the substituents are selected from halogen, C1-C3Alkyl radical, C2-C4Alkenyl, -CN, sulfonyl or ester group.
According to an embodiment of the application, the compound having a nitrile group comprises At least one of (1).
According to an embodiment of the present application, the compound having a nitrile group is contained in an amount of 0.01 wt% to 10 wt%, based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.08 to 8 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.1 to 7 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.5 to 6 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.5 to 5 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.5 to 3 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.5 to 2.5 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.01 wt%, 0.03 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 4 wt%, 5 wt%, 7 wt%, 8 wt%, or 10 wt%, based on the total weight of the electrolyte.
According to an embodiment of the application, the electrolyte further comprises a compound of formula V:
wherein:
R38and R39Each independently selected from substituted or unsubstituted C1-C10Alkyl, substituted or unsubstituted C2-C10Alkenyl or substituted or unsubstituted C2-C10Alkynyl and
when substituted, the substituents are selected from halogen, C1-C3At least one of fluoroalkyl, sulfone, -CN, or ether groupsOne kind of the material is selected;
provided that R is38And R39At least one of which contains fluorine atoms.
According to an embodiment of the application, the compound of formula V is selected from
At least one of (1).
According to an embodiment of the present application, the compound of formula V is contained in an amount of 0.1 wt% to 40 wt%, based on the total weight of the electrolyte. In some embodiments, the compound of formula V is present in an amount of 0.5 wt% to 35 wt%, based on the total weight of the electrolyte. In some embodiments, the compound of formula V is present in an amount of 1 wt% to 30 wt%, based on the total weight of the electrolyte. In some embodiments, the compound of formula V is present in an amount of 5 wt% to 25 wt%, based on the total weight of the electrolyte. In some embodiments, the compound of formula V is present in an amount of 10 wt% to 20 wt%, based on the total weight of the electrolyte. In some embodiments, the compound of formula V is present in an amount of 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt%, based on the total weight of the electrolyte.
In some embodiments, when any of the above groups are substituted, the substituent is fluorine, chlorine, bromine, or iodine. In some embodiments, when any of the above groups are substituted, the substituent is fluoro or chloro. In some embodiments, when any of the above groups is substituted, the substituent is fluoro.
According to another aspect of the present application, there is provided an electrochemical device comprising a positive electrode, a negative electrode and an electrolyte according to the present application.
According to yet another aspect of the present application, there is provided an electronic device comprising an electrochemical device according to the present application.
Additional aspects and advantages of the present application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of embodiments of the present application.
Detailed Description
Embodiments of the present application will be described in detail below. The embodiments of the present application should not be construed as limiting the present application.
In the detailed description and claims, a list of items joined by the term "at least one of may mean any combination of the listed items. For example, if items a and B are listed, the phrase "at least one of a and B" means a only; only B; 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 only B; only C; a and B (excluding C); a and C (excluding B); b and C (excluding A); or A, B and C. Item a may comprise a single element or multiple elements. Item B may comprise a single element or multiple elements. Item C may comprise a single element or multiple elements.
As used herein, the term "hydrocarbyl" includes, but is not limited to, aliphatic hydrocarbyl groups, including linear and cyclic, specifically including, but not limited to, alkyl, alkenyl, and alkynyl groups, and aromatic hydrocarbyl groups, including, but not limited to, 6-to 12-membered aromatic hydrocarbyl groups, such as benzene, naphthalene, and the like.
As used herein, 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 from 3 to 20 carbon atoms. When an alkyl group having a particular carbon number is specified, all geometric isomers having that carbon number are intended to be encompassed; 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, and the like.
As used herein, the term "alkenyl" refers to a monovalent unsaturated hydrocarbon group that can be straight-chain or branched and has at least one and typically 1,2, or 3 carbon-carbon double bonds. Unless otherwise defined, the alkenyl groups typically contain 2 to 20 carbon atoms and include, for example, -C2-4Alkenyl, -C2-6Alkenyl and-C2-10An alkenyl group. Representative alkenyl groups include, by way of example, ethenyl, n-propenyl, isopropenyl, n-but-2-enyl, but-3-enyl, n-hex-3-enyl, and the like.
As used herein, the term "alkynyl" refers to a monovalent unsaturated hydrocarbon group that can be straight-chain or branched and has at least one, and typically 1,2, or 3 carbon-carbon triple bonds. Unless otherwise defined, the alkynyl group typically contains 2 to 20 carbon atoms and includes, for example, -C2-4Alkynyl, -C3-6Alkynyl and-C3-10Alkynyl. Representative alkynyl groups include, for example, ethynyl, prop-2-ynyl (n-propynyl), n-but-2-ynyl, n-hex-3-ynyl, and the like.
As used herein, the term "alkylene" means a divalent saturated hydrocarbon group that may be straight-chain or branched. Unless otherwise defined, the alkylene groups typically contain 2 to 20 carbon atoms and include, for example, -C2-3Alkylene and-C2-6Alkylene-. Representative alkylene groups include, for example, methylene, ethane-1, 2-diyl ("ethylene"), propane-1, 2-diyl, propane-1, 3-diyl, butane-1, 4-diyl, pentane-1, 5-diyl, and the like.
As used herein, the term "alkenylene" encompasses both straight-chain and branched alkenylene groups. When an alkenylene group having a particular carbon number is specified, all geometric isomers having that carbon number are intended to be encompassed. For example, the alkenylene group may be an alkenylene group having 2 to 20 carbon atoms, an alkenylene group having 2 to 15 carbon atoms, an alkenylene group having 2 to 10 carbon atoms, an alkenylene group having 2 to 5 carbon atoms, an alkenylene group having 5 to 20 carbon atoms, an alkenylene group having 5 to 15 carbon atoms, or an alkenylene group having 5 to 10 carbon atoms. Representative alkylene groups include, for example, ethenylene, propenylene, butenylene, and the like.
As used herein, the term "aryl" means a monovalent aromatic hydrocarbon having a single ring (e.g., phenyl) or fused rings. Fused ring systems include those that are fully unsaturated (e.g., naphthalene) as well as those that are partially unsaturated (e.g., 1,2,3, 4-tetrahydronaphthalene). Unless otherwise defined, the aryl group typically contains from 6 to 26 carbon ring atoms and includes, for example, -C6-10And (4) an aryl group. Representative aryl groups include, for example, phenyl, methylphenyl, propylphenyl, isopropylphenyl, benzyl, and naphthalen-1-yl, naphthalen-2-yl, and the like.
As used herein, the term "arylene" encompasses monocyclic and polycyclic ring systems. Polycyclic rings can have two or more rings in which two carbons are common to two adjoining rings (the rings are "fused"), wherein at least one of the rings is aromatic, e.g., the other rings can be cycloalkyls, cycloalkenyls, aryls, heterocyclics, and/or heteroaryls. For example, the arylene group can be C6-C50Arylene radical, C6-C40Arylene radical, C6-C30Arylene radical, C6-C26Arylene radical, C6-C20Arylene radicals or C6-C10An arylene group. Specific examples of the arylene group include: phenylene, benzylene, 1-naphthylene, 2-naphthylene, o-methylphenylene, m-methylphenylene, p-ethylphenylene, m-ethylphenylene, o-ethylphenylene, 1-tetrahydronaphthylene, 2-tetrahydronaphthylene, 4-vinylphenylene, 3-isopropylphenylene, 4-butylphenyl, 4-isobutylphenylene, 4-tert-butylphenyl, 2, 3-dimethylphenylene, 2, 4-dimethylphenylene, 2, 5-dimethylphenylene, 2, 6-dimethylphenylene, 3, 4-dimethylphenylene, 3, 5-dimethylphenylene, 2,4, 5-trimethylphenylene, 2,4, 6-trimethylphenylene and the like.
As used herein, the term "halogen" may be fluorine, chlorine, bromine or iodine.
As used herein, the term "fluoro" means that at least one hydrogen atom in a substituted group is replaced with a fluorine atom.
With the widespread use of electrochemical devices, such as lithium ion batteries, safety performance, cycle performance, and storage performance are receiving much attention. However, the kinetic performance (e.g., cycle life) of an electrochemical device is often sacrificed in order to improve its safety. For example, adding a flame retardant to an electrolyte is one of methods for improving the safety of an electrochemical device, but the flame retardant generally has a high viscosity and is less stable to a negative electrode, thereby causing an increase in the impedance of the electrochemical device, a severe gassing phenomenon during storage in a full charge state, and a decrease in the cycle performance of the electrochemical device.
In order to improve the safety, kinetic performance and storage performance of electrochemical devices, the present application provides an electrolyte comprising an ionic liquid, wherein the ionic liquid comprises a first ionic liquid component and a second ionic liquid component. In some embodiments, the ionic liquid further comprises a third ionic liquid component. In some embodiments, the electrolyte further includes a compound having a nitrile group. In some embodiments, the electrolyte further comprises a fluorocarboxylic acid ester. In some embodiments, the electrolyte further comprises an additive. In some embodiments, the electrolyte further comprises a solvent. In some embodiments, the electrolyte further comprises a lithium salt.
Ionic liquids
The ionic liquid is a salt which is liquid at room temperature or close to room temperature and consists of anions and cations. The ionic liquid has extremely low saturated vapor pressure and higher thermal stability (the thermal decomposition temperature is generally more than 250 ℃), and the thermal stability and the safety of the electrolyte are improved.
In some embodiments, the weight of the ionic liquid is 0.01 wt% to 25 wt%, based on the total weight of the electrolyte. In some embodiments, the weight of the ionic liquid is 0.05 wt% to 20 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 0.08 wt% to 18 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 0.1 wt% to 15 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 0.5 wt% to 12 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 1 wt% to 10 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 2 wt% to 8 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 3 wt% to 5 wt%, based on the total weight of the electrolyte. In some embodiments, the ionic liquid is present in an amount of 0.01, 0.03, 0.05, 0.1, 0.5, 1,2, 5, 8, 10, 12, 15, 18, 20, 22, or 25 wt% based on the total weight of the electrolyte. When the content of the ionic liquid in the electrolyte is within the range, the ionic liquid has proper viscosity, and an electrode interface can be effectively protected, so that the side reaction between the electrolyte and the anode and the cathode can be effectively reduced, and the safety, the dynamic performance and the storage performance of the electrochemical device can be improved.
A first ionic liquid component
In various embodiments herein, the first ionic liquid component has an alkenyl group. The first ionic liquid component containing alkenyl can be reduced to form a film on the negative electrode, so that the side reaction of the electrolyte and the electrode is reduced, the thermal stability of the negative electrode is improved, the thermal diffusion generated by the partial short circuit negative electrode is inhibited, and the safety of an electrochemical device is improved.
In various embodiments of the present application, the first ionic liquid component comprises a cation of formula I:
wherein:
R1selected from the group consisting of substituted or unsubstituted imidazolium cations, substituted or unsubstituted pyrrolium cations, substituted or unsubstituted pyridinium cations, substituted or unsubstituted piperazinesA pyridine cation, a substituted or unsubstituted ammonium cation, or a substituted or unsubstituted phosphonium cation;
R2selected from covalent bond, substituted or unsubstituted C1-C8Alkylene or substituted or unsubstituted C1-C8Alkenylene, substituted or unsubstituted C6-C12An arylene group;
1≤x≤6；
wherein when substituted, the substituents are selected from halogen, C1-C3Alkyl radical, C2-C4At least one of alkenyl or-CN.
In some embodiments, the cation in the first ionic liquid component comprises At least one of (a) and (b),
wherein:
R11、R12、R14、R15、R17、R18、R19、R20and R21Each independently selected from substituted or unsubstituted C1-C8Alkyl or substituted or unsubstituted C6-C12An aryl group;
R13and R16Each independently selected from substituted or unsubstituted C1-C8Alkylene or substituted or unsubstituted C6-C12An arylene group;
wherein when substituted, the substituents are selected from halogen, -CN, C1-C3Alkyl radical, C2-C4At least one of an alkenyl group or a sulfone group.
In some embodiments, when R1、R2、R11、R12、R13、R14、R15、R16、R17、R18、R19、R20And R21When at least one of them is substituted, the substitutionThe radical is fluorine, chlorine, bromine or iodine. In some embodiments, when R1、R2、R11、R12、R13、R14、R15、R16、R17、R18、R19、R20And R21When at least one of them is substituted, the substituent is fluorine or chlorine. In some embodiments, when R1、R2、R11、R12、R13、R14、R15、R16、R17、R18、R19、R20And R21When at least one of them is substituted, the substituent is fluorine.
In some embodiments, the anion in the first ionic liquid component is selected from hexafluorophosphate (PF)6 -) Bis (trifluoromethyl) sulfonate (TFSI)-) bis-Fluoromethylsulfonate (FSI)-) Bis (oxalato) borate (BOB)-) Difluoro oxalato borate (DFOB)-) Or tetrafluoroborate (BF)4 -) At least one of (1).
In some embodiments, the first ionic liquid component comprises at least one of the following compounds:
in some embodiments, the first ionic liquid component is present in an amount of 0.01 wt% to 10 wt%, based on the total weight of the electrolyte. In some embodiments, the first ionic liquid component is present in an amount of 0.05 wt% to 8 wt%, based on the total weight of the electrolyte. In some embodiments, the first ionic liquid component is present in an amount of 0.1 wt% to 7 wt%, based on the total weight of the electrolyte. In some embodiments, the first ionic liquid component is present in an amount of 0.5 wt% to 5 wt%, based on the total weight of the electrolyte. In some embodiments, the first ionic liquid component is present in an amount of 0.5 wt% to 4 wt%, based on the total weight of the electrolyte. In some embodiments, the first ionic liquid component is present in an amount of 0.01, 0.03, 0.05, 0.1, 0.5, 1,2, 5, 8, or 10 wt%, based on the total weight of the electrolyte.
A second ionic liquid component
In various embodiments herein, the second ionic liquid component comprises nitrile groups. The second ionic liquid component containing nitrile groups can be coordinated with transition metal on the surface of the anode, and the phase change of the anode material caused by the dissolution of the transition metal is inhibited, so that the oxygen release of the anode is inhibited, and the thermal stability of the anode is improved.
In various embodiments herein, the second ionic liquid component comprises at least one cation having the formula II-:
wherein:
R3selected from the group consisting of substituted or unsubstituted imidazolium cations, substituted or unsubstituted pyrrol cations, substituted or unsubstituted pyridinium cations, substituted or unsubstituted piperidinium cations, substituted or unsubstituted phosphonium cations, and substituted or unsubstituted ammonium cations;
R4selected from substituted or unsubstituted C1-C8Alkylene, substituted or unsubstituted C1-C8Alkenylene or substituted or unsubstituted C6-C12An arylene group;
1≤y≤6；
wherein when substituted, the substituents are selected from halogen, C1-C3Alkyl radical, C2-C4At least one of an alkenyl group, -CN, or sulfone group.
In some embodiments, the cation in the second ionic liquid component comprises At least one of (a) and (b),
wherein:
R22、R23、R25、R26、R27and R28Each independently selected from substituted or unsubstituted C1-C8Alkyl, substituted or unsubstituted C6-C12An aryl group;
R24selected from substituted or unsubstituted C1-C8Alkylene or substituted or unsubstituted C6-C12An arylene group;
wherein when substituted, the substituents are selected from halogen, -CN, C1-C3Alkyl radical, C2-C4At least one of an alkenyl group or a sulfone group.
In some embodiments, when R3、R4、R22、R23、R24、R25、R26、R27And R28When at least one of them is substituted, the substituent is fluorine, chlorine, bromine or iodine. In some embodiments, when R3、R4、R22、R23、R24、R25、R26、R27And R28When at least one of them is substituted, the substituent is fluorine or chlorine. In some embodiments, when R3、R4、R22、R23、R24、R25、R26、R27And R28When at least one of them is substituted, the substituent is fluorine.
In some embodiments, the anion in the second ionic liquid component is selected from hexafluorophosphate (PF)6 -) Bis (trifluoromethyl) sulfonate (TFSI)-) bis-Fluoromethylsulfonate (FSI)-) Bis (oxalato) borate (BOB)-) Difluoro oxalato borate (DFOB)-) Or tetrafluoroborate (BF)4 -) At least one of (1).
In some embodiments, the second ionic liquid component comprises at least one of the following compounds:
in some embodiments, the second ionic liquid component is present in an amount of 0.01 wt% to 10 wt%, based on the total weight of the electrolyte. In some embodiments, the second ionic liquid component is present in an amount of 0.05 wt% to 8 wt%, based on the total weight of the electrolyte. In some embodiments, the second ionic liquid component is present in an amount of 0.1 wt% to 5 wt%, based on the total weight of the electrolyte. In some embodiments, the second ionic liquid component is present in an amount of 0.5 wt% to 3 wt%, based on the total weight of the electrolyte. In some embodiments, the second ionic liquid component is present in an amount of 1 wt% to 2 wt%, based on the total weight of the electrolyte. In some embodiments, the second ionic liquid component is present in an amount of 0.01, 0.03, 0.05, 0.1, 0.5, 1,2, 5, 8, or 10 wt%, based on the total weight of the electrolyte.
In some embodiments, the weight ratio of the first ionic liquid component to the second ionic liquid component is from 1:99 to 99:1, based on the total weight of the electrolyte. In some embodiments, the weight ratio of the first ionic liquid component to the second ionic liquid component is from 10:90 to 90:10, based on the total weight of the electrolyte. In some embodiments, the weight ratio of the first ionic liquid component to the second ionic liquid component is from 20:80 to 80:20, based on the total weight of the electrolyte. In some embodiments, the weight ratio of the first ionic liquid component to the second ionic liquid component is from 30:70 to 70:30, based on the total weight of the electrolyte. In some embodiments, the weight ratio of the first ionic liquid component to the second ionic liquid component is from 40:60 to 60:40, based on the total weight of the electrolyte. The weight ratio of the first ionic liquid component to the second ionic liquid component is 1:99, 5:95, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, 95:5, or 99:1, based on the total weight of the electrolyte.
The first ionic liquid component and the second ionic liquid component can be reduced to form a film at the negative electrode under the combined action, so that the side reaction of the electrolyte and the electrode is reduced, the heat stability of the negative electrode is improved, and the phase change of the positive electrode material caused by the dissolution of the transition metal is inhibited, so that the oxygen release of the positive electrode is inhibited, the heat stability of the positive electrode is improved, and the safety performance of the battery cell can be obviously improved under the synergistic action of the first ionic liquid component and the second ionic liquid component.
A third ionic liquid component
In some embodiments, the third ionic liquid component has a fluoroalkylene group. The first ionic liquid component, the second ionic liquid component and the third ionic liquid component with the fluorinated alkylene can further reduce the surface tension of the ionic liquid, improve the wettability of the electrolyte and reduce the interface polarization and impedance of the electrode under the combined action.
In some embodiments, the third ionic liquid component comprises at least one cation having the formula III:
wherein:
R29and R30Each independently selected from a fluorine atom, a fluorinated hydrocarbon, a fluorinated aromatic hydrocarbon or a sulfone group; and is
2≤z≤6；
And the anion in the third ionic liquid component is selected from at least one of hexafluorophosphate, bis-trifluoromethylsulfonate, bis-fluoromethylsulfonate, bis-oxalato borate, difluoro-oxalato borate or tetrafluoroborate.
In some embodiments, the third ionic liquid component comprises at least one of the following compounds:
in some embodiments, the third ionic liquid component is present in an amount of 0.01 wt% to 20 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 0.05 wt% to 18 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 0.1 wt% to 15 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 0.5 wt% to 12 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 1 wt% to 10 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 1 wt% to 8 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 1 wt% to 5 wt%, based on the total weight of the electrolyte. In some embodiments, the third ionic liquid component is present in an amount of 0.01, 0.03, 0.05, 0.1, 0.5, 1,2, 5, 8, 10, 12, 15, 18, or 20 wt% based on the total weight of the electrolyte.
Compound having nitrile group
The first ionic liquid component and the second ionic liquid component act together with the compound with a plurality of nitrile groups, so that the electrolyte has excellent chemical stability, thermal stability and oxidation resistance, and can have lower surface tension, and a compact and stable protective film can be formed on the surface of an electrode, so that the thermal runaway risk of the electrolyte on the surface of the electrode during overcharge of an electrochemical device is reduced, and the safety of the electrochemical device is improved. Meanwhile, the compound with a plurality of nitrile groups has a higher oxidation potential, and is beneficial to remarkably improving the cycle performance and the high-temperature storage performance of the high-voltage electrochemical device.
In some embodiments, the compound having a nitrile group comprises at least one of a compound of formula IV-a or a compound of formula IV-B:
wherein:
R31、R32、R34、R35、R36and R37Each independently selected from-OR0-, substituted or unsubstituted C1-C10Alkylene, substituted or unsubstituted C2-C10Alkenylene or sulfonyl;
R0selected from substituted or unsubstituted C1-C5Alkylene, substituted or unsubstituted C2-C6An alkenylene group;
R33selected from hydrogen, substituted or unsubstituted C1-C10Alkyl, substituted or unsubstituted C2-C10Alkenyl or sulfonyl, wherein when substituted, the substituents are selected from halogen, C1-C3Alkyl radical, C2-C4Alkenyl, -CN, sulfonyl or ester group.
In some embodiments, when R31、R32、R33、R34、R35、R36、R37And R0When at least one of them is substituted, the substituent is fluorine, chlorine, bromine or iodine. In some embodiments, when R31、R32、R33、R34、R35、R36、R37And R0When at least one of them is substituted, the substituent is fluorine or chlorine. In some embodiments, when R31、R32、R33、R34、R35、R36、R37And R0When at least one of them is substituted, the substituent is fluorine.
In some embodiments, the compound having a nitrile group comprises At least one of (1).
According to an embodiment of the present application, the compound having a nitrile group is contained in an amount of 0.01 wt% to 10 wt%, based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.08 to 8 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.1 to 7 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.5 to 6 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.5 to 5 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.5 to 3 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.5 to 2.5 wt% based on the total weight of the electrolyte. In some embodiments, the compound having a nitrile group is contained in an amount of 0.01 wt%, 0.03 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 4 wt%, 5 wt%, 7 wt%, 8 wt%, or 10 wt%, based on the total weight of the electrolyte. When the content of the compound having a nitrile group in the electrolyte is within the above range, the negative electrode can be effectively passivated, a side reaction between the electrolyte and the positive electrode is prevented, and it is helpful to improve the safety, kinetic properties, and storage properties of the electrochemical device.
Fluorocarboxylic acid esters
The fluorocarboxylate has excellent chemical stability, thermal stability and oxidation resistance, and can provide a low surface tension to an electrolyte, which can form a dense and stable protective film on the surface of an electrode, thereby reducing the risk of thermal runaway of the electrolyte on the surface of the electrode during overcharge of an electrochemical device, thereby improving the safety of the electrochemical device. Meanwhile, the fluorocarboxylate has lower viscosity and higher dielectric constant, and can improve the dynamic performance of the electrolyte.
In some embodiments, the fluorocarboxylic acid ester comprises at least one compound of formula V:
wherein:
R38and R39Each independently selected from substituted or unsubstituted C1-C10Alkyl, substituted or unsubstituted C2-C10Alkenyl or substituted or unsubstituted C2-C10Alkynyl and
when substituted, the substituents are selected from halogen, C1-C3At least one of fluoroalkyl group, sulfone group, -CN or ether group;
provided that R is38And R39At least one of which contains fluorine atoms.
In some embodiments, when R38And R39When at least one of them is substituted, the substituent is fluorine, chlorine, bromine or iodine. In some embodiments, when R38And R39When at least one of them is substituted, the substituent is fluorine or chlorine. In some embodiments, when R38And R39When at least one of them is substituted, the substituent is fluorine.
In some embodiments, the compound of formula V is selected from
At least one of (1).
In some embodiments, the compound of formula V is present in an amount of 0.1 wt% to 40 wt%, based on the total weight of the electrolyte. In some embodiments, the compound of formula V is present in an amount of 0.5 wt% to 35 wt%, based on the total weight of the electrolyte. In some embodiments, the compound of formula V is present in an amount of 1 wt% to 30 wt%, based on the total weight of the electrolyte. In some embodiments, the compound of formula V is present in an amount of 5 wt% to 25 wt%, based on the total weight of the electrolyte. In some embodiments, the compound of formula V is present in an amount of 10 wt% to 20 wt%, based on the total weight of the electrolyte. In some embodiments, the compound of formula V is present in an amount of 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, 22 wt%, 25 wt%, 30 wt%, 35 wt%, or 40 wt%, based on the total weight of the electrolyte.
Additive agent
In some embodiments, the additive comprises Vinylene Carbonate (VC). In some embodiments, the vinylene carbonate is present in an amount ranging from 0.1 wt% to 4 wt%, based on the total weight of the electrolyte. In some embodiments, the vinylene carbonate is present in an amount ranging from 0.5 wt% to 3 wt%, based on the total weight of the electrolyte. In some embodiments, the vinylene carbonate is present in an amount ranging from 1 wt% to 2 wt%, based on the total weight of the electrolyte. In some embodiments, the vinylene carbonate is present in an amount of 0.1 wt%, 0.2 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, or 4 wt%, based on the total weight of the electrolyte. When the content of the vinylene carbonate in the electrolyte is within the above range, a Solid Electrolyte Interface (SEI) film can be formed on the surface of the negative electrode and the lithium deposition phenomenon of the electrochemical device at low temperature can be significantly reduced, effectively improving the cycle performance and storage performance of the electrochemical device.
In some embodiments, the additive comprises fluoroethylene carbonate (FEC). In some embodiments, the fluoroethylene carbonate is present in an amount of 0.5 wt% to 10 wt%, based on the total weight of the electrolyte. In some embodiments, the fluoroethylene carbonate is present in an amount of 1 wt% to 8 wt%, based on the total weight of the electrolyte. In some embodiments, the fluoroethylene carbonate is present in an amount of 2 wt% to 5 wt%, based on the total weight of the electrolyte. In some embodiments, the fluoroethylene carbonate is present in an amount of 0.5 wt%, 0.8 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%, based on the total weight of the electrolyte. When the content of fluoroethylene carbonate in the electrolyte is within the above range, it may form a Solid Electrolyte Interface (SEI) film on the surface of the negative electrode, effectively improving cycle performance and storage performance of the electrochemical device.
In some embodiments, the additive comprises 1, 3-Propane Sultone (PS). In some embodiments, the 1, 3-propane sultone is present in an amount of 0.1 wt% to 5 wt%, based on the total weight of the electrolyte. In some embodiments, the 1, 3-propane sultone is present in an amount of 0.5 wt% to 3 wt%, based on the total weight of the electrolyte. In some embodiments, the 1, 3-propane sultone is present in an amount of 1 wt% to 2 wt%, based on the total weight of the electrolyte. In some embodiments, the 1, 3-propane sultone is present in an amount of 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, or 5 weight percent based on the total weight of the electrolyte. When the content of the 1, 3-propane sultone in the electrolyte is within the above range, it may form a Solid Electrolyte Interface (SEI) film on the surface of the negative electrode, effectively improving cycle performance and storage performance of the electrochemical device.
In some embodiments, the additive includes lithium difluorooxalato borate (L idodfb). in some embodiments, the lithium difluorooxalato borate is present in an amount of 0.1 wt% to 2 wt% based on the total weight of the electrolyte solution.in some embodiments, the lithium difluorooxalato borate is present in an amount of 0.5 wt% to 1 wt% based on the total weight of the electrolyte solution.in some embodiments, the lithium difluorooxalato borate is present in an amount of 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, or 2 wt% based on the total weight of the electrolyte solution.
Solvent(s)
In some embodiments, the solvent comprises an organic solvent. The specific kind of the organic solvent is not limited, and it may include, but is not limited to, a chain carbonate, a cyclic carbonate, a chain carboxylate, a cyclic carboxylate, or an ether. In some embodiments, the organic solvent comprises at least one of: dimethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, methyl butyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, methyl valerate, ethyl valerate, methyl pivalate, ethyl pivalate, butyl pivalate, gamma-butyrolactone, or gamma-valerolactone.
Lithium salt
In some embodiments, the lithium salt includes at least one of an inorganic lithium salt or an organic lithium salt species including, but not limited to, lithium hexafluorophosphate (L iPF)6) Lithium tetrafluoroborate (L iBF)4) Lithium hexafluoroarsenate, lithium perchlorate, lithium bis (fluorosulfonyl) imide (L iFSI), lithium bis (trifluoromethanesulfonyl) imide (L iTFSI), lithium bis (L iBOB) or lithium difluoro (L iODFB)6)。
In some embodiments, the concentration of the lithium salt in the electrolyte is 0.8 mol/L to 1.2 mol/L in some embodiments, the concentration of the lithium salt in the electrolyte is 0.8 mol/L, 0.9 mol/L, 1 mol/L, 1.1 mol/L, 1.2 mol/L.
The electrolyte according to the present application may be prepared by any known method, for example, by uniformly mixing the components in the electrolyte.
Based on the above-described aspects, the negative electrode, the positive electrode, the separator, the electrochemical device, and the electronic device, which can be used in the present application, are described in detail below.
Negative electrode
The negative electrode includes a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector. The specific kind of the negative active material is not particularly limited and may be selected as desired.
In some embodiments, the negative active material may include, but is not limited to, natural graphite, artificial graphite, mesophase micro carbon spheres (abbreviated as MCMB), hard carbon, soft carbon, silicon-carbon composite, L i-Sn alloy, L i-Sn-O alloy, Sn, SnO2Spinel-structured lithiated TiO2-Li4Ti5O12Non-limiting examples of carbon materials include crystalline carbon, amorphous carbon, and mixtures thereof, the crystalline carbon may be amorphous or platelet-shaped, spherical, or fibrous natural or artificial graphite, the amorphous carbon may be soft carbon, hard carbon, mesophase pitch carbide, calcined coke, and the like.
According to an embodiment of the present application, the negative electrode further includes a conductive layer. In some embodiments, the conductive material of the conductive layer may include any conductive material as long as it does not cause a chemical change. Non-limiting examples of the conductive material include carbon-based materials (e.g., natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fibers, carbon nanotubes, graphene, etc.), metal-based materials (e.g., metal powders, metal fibers, etc., such as copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives), and mixtures thereof.
According to an embodiment of the present application, the anode further comprises a binder selected from at least one of: polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene 1, 1-difluoroethylene, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, or the like.
The negative current collector used herein may be selected from the group consisting of copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, polymer substrates coated with conductive metals, and combinations thereof.
Positive electrode
The positive electrode includes a positive electrode current collector and a positive electrode active material disposed on the positive electrode current collector. The specific kind of the positive electrode active material is not particularly limited and may be selected as desired.
In some embodiments, the positive active material includes a compound that reversibly intercalates and deintercalates lithium ions. In some embodiments, the positive active material may include a compositeIn still other embodiments, the positive active material is selected from the group consisting of lithium cobaltate (L iCoO)2) Lithium nickel manganese cobalt ternary material and lithium manganate (L iMn)2O4) Lithium nickel manganese oxide (L iNi)0.5Mn1.5O4) And lithium iron phosphate (L iFePO)4) One or more of them.
In some embodiments, the positive electrode active material layer may have a coating layer on the surface, or may be mixed with another compound having a coating layer. The coating may include at least one coating element compound selected from an oxide of the coating element, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate (oxycarbonate) of the coating element, and an oxycarbonate (hydroxycarbonate) of the coating element. The compounds used for the coating may be amorphous or crystalline. The coating element contained in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, F, or a mixture thereof. The coating layer may be applied by any method as long as the method does not adversely affect the properties 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 comprises a binder, and optionally further comprises a positive conductive material.
The binder may improve the binding of the positive electrode active material particles to each other and also improve the binding of the positive electrode active material to the current collector. Non-limiting examples of binders include polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene 1, 1-difluoride, polyethylene, polypropylene, styrene butadiene rubber, acrylated styrene butadiene rubber, epoxy, nylon, and the like.
The positive electrode active material layer includes a positive electrode conductive material, thereby imparting conductivity to the electrode. The positive electrode conductive material may include any conductive material as long as it does not cause a chemical change. Non-limiting examples of the positive electrode conductive material include carbon-based materials (e.g., natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, etc.), metal-based materials (e.g., metal powder, metal fiber, etc., including, for example, copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives), and mixtures thereof.
The positive electrode current collector for the electrochemical device according to the present application may be aluminum (Al), but is not limited thereto.
Isolation film
In some embodiments, a separator is provided between the positive and negative electrodes to prevent short circuits. The material and shape of the separation film that can be used for the embodiment of the present application are not particularly limited, and may be any of the techniques disclosed in the prior art. In some embodiments, the separator includes a polymer or inorganic substance or the like formed of a material stable to the electrolyte of the present application.
For example, the release film may include a substrate layer and a surface treatment layer. The substrate layer is a non-woven fabric, a film or a composite film with a porous structure, and the material of the substrate layer is at least one selected from polyethylene, polypropylene, polyethylene terephthalate and polyimide. Specifically, a polypropylene porous film, a polyethylene porous film, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, or a polypropylene-polyethylene-polypropylene porous composite film can be used.
At least one surface of the substrate layer is provided with a surface treatment layer, and the surface treatment layer can be a polymer layer or an inorganic layer, or a layer formed by mixing a polymer and an inorganic substance.
The inorganic layer comprises inorganic particles and a binder, wherein the inorganic particles are selected from one or more of aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium oxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium sulfate. The binder is selected from one or a combination of more of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene and polyhexafluoropropylene.
The polymer layer comprises a polymer, and the material of the polymer is selected from at least one of polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride and poly (vinylidene fluoride-hexafluoropropylene).
Electrochemical device
The electrochemical device of the present application includes any device in which electrochemical reactions occur, 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.
Electronic device
The present application further provides an electronic device comprising an electrochemical device according to the present application.
The use of the electrochemical device of the present application is not particularly limited, and it can be used for any electronic device known in the art. In some embodiments, the electrochemical device of the present application can be used in, but is not limited to, notebook computers, pen-input computers, mobile computers, electronic book players, cellular phones, portable facsimile machines, portable copiers, portable printers, head-mounted stereo headphones, video recorders, liquid crystal televisions, hand-held cleaners, portable CDs, mini-discs, transceivers, electronic organizers, calculators, memory cards, portable recorders, radios, backup power sources, motors, automobiles, motorcycles, mopeds, bicycles, lighting fixtures, toys, game consoles, clocks, electric tools, flashlights, cameras, household large-sized batteries, lithium ion capacitors, and the like.
Taking a lithium ion battery as an example and describing the preparation of the lithium ion battery with reference to specific examples, those skilled in the art will understand that the preparation method described in the present application is only an example, and any other suitable preparation method is within the scope of the present application.
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