CN117154214A - Electrolyte, secondary battery and electricity utilization device - Google Patents

Electrolyte, secondary battery and electricity utilization device Download PDF

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Publication number
CN117154214A
CN117154214A CN202311413641.5A CN202311413641A CN117154214A CN 117154214 A CN117154214 A CN 117154214A CN 202311413641 A CN202311413641 A CN 202311413641A CN 117154214 A CN117154214 A CN 117154214A
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Prior art keywords
electrolyte
carbon atoms
halogen
substituted
based solvent
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CN202311413641.5A
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Chinese (zh)
Inventor
吴凯
钟铭
靳超
叶永煌
代志鹏
郑仕兵
吴子睿
严观福生
张鑫
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Priority to CN202311413641.5A priority Critical patent/CN117154214A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane

Abstract

The application relates to an electrolyte, a secondary battery and an electric device, wherein the electrolyte comprises the components of cyclosiloxane compounds shown in a formula (1): wherein R is 1 And R is 2 Are each independently selected from H, halogen, aryl having 6 to 10 ring-forming atoms, alkyl having 1 to 10 carbon atoms, halogen-substituted alkyl having 1 to 10 carbon atoms, aryl having 6 to 10 ring-forming atoms andany one of them, and R 1 And R is 2 Not simultaneously H; r is R 3 Any one selected from an alkylene group having 1 to 5 carbon atoms and an alkylene group having 1 to 5 carbon atoms substituted with halogen; r is R 4 And R is 5 Independently selected from H, an alkoxy group having 1 to 10 carbon atoms, and a carbon atom substituted with halogenAny one of alkoxy with 1-10 sub-numbers and R 1 And R is 2 Not simultaneously H; "x" represents the site of attachment, ""represents that atoms at two ends are connected to form a ring, and n is any integer from 3 to 5.

Description

Electrolyte, secondary battery and electricity utilization device
Technical Field
The application relates to the technical field of batteries, in particular to electrolyte, a secondary battery and an electric device.
Background
Secondary batteries such as lithium batteries are increasingly widely used due to their clean and renewable characteristics, and have a relatively high specific energy density and a relatively long cycle life, and have been widely used in many fields such as consumer electronics, electric vehicles, energy storage, and the like.
Along with the expansion of the application range of the secondary battery, the electrochemical window range of the secondary battery is required to be higher and higher, the electrochemical window can be widened to adapt to various application situations, and meanwhile, the safety performance is important. However, the conventional secondary battery is easy to generate by-product reactions such as oxidation or decomposition in the charge and discharge process, so that the electrochemical window is too narrow, the application expansion of the secondary battery is restricted, thermal runaway is easy to generate, the battery is scrapped by a light person, and safety accidents are also caused by serious persons.
Therefore, the electrochemical window and safety performance of the conventional secondary battery are required to be further improved.
Disclosure of Invention
Based on this, it is necessary to provide an electrolyte, a secondary battery, and an electric device, which aim to widen the electrochemical window of the secondary battery and improve the safety performance thereof.
The application is realized by the following technical scheme.
In a first aspect of the present application, there is provided an electrolyte, the electrolyte comprising a cyclosiloxane compound represented by formula (1):
，
wherein each R 1 And each R 2 Are each independently selected from H, halogen, substituted or unsubstituted aryl groups having 6 to 10 ring-forming atoms, alkyl groups having 1 to 10 carbon atoms, halogen-substituted alkyl groups having 1 to 10 carbon atoms, and At least one R of a plurality of repeating units of the cyclosiloxane compound 1 Or at least one R 2 Selected from substituted or unsubstituted aryl or +.>；
R 3 Any one selected from an alkylene group having 1 to 5 carbon atoms and an alkylene group having 1 to 5 carbon atoms substituted with halogen; r is R 4 And R is 5 Each independently selected from any one of H, an alkoxy group having 1 to 10 carbon atoms and an alkoxy group having 1 to 10 carbon atoms substituted with halogen, and R 4 And R is 5 Not simultaneously H;
"x" represents the site of attachment, ""represents that atoms at two ends are connected to form a ring, and n is any integer from 3 to 5.
The components of the electrolyte contain cyclosiloxane compounds with specific structures, the cyclosiloxane compounds shown in the formula (1) contain a cyclosiloxane main structure and specific hydrocarbon groups connected to the main structure, on one hand, the cyclosiloxane main structure has higher thermal stability and chemical stability, the cyclosiloxane main structure can undergo a ring-opening reaction when the temperature is increased, byproducts such as LiCX and the like are subjected to real-time targeted passivation, the exothermic side reaction of the cyclosiloxane main structure and the electrolyte is effectively inhibited, the SEI film is subjected to targeted repair, and gel substances can be polymerized when the ring-opening reaction is carried out to a certain extent, and the gel substances adhere to a diaphragm to play a supporting role to inhibit the shrinkage of the isolating film; on the other hand, the chemical stability of the cyclosiloxane compound is further improved by the specific hydrocarbon groups connected to the main structure, and each specific structure is organically combined, so that the electrochemical window of the electrolyte is widened, the thermal runaway critical point of the electrolyte is improved, the thermal runaway trigger temperature of the secondary battery can be improved, the occurrence of thermal runaway is delayed, and the electrochemical window is widened when the electrolyte is applied to the preparation of the secondary battery.
The chemical stability of the aryl is higher, and halogen or the phosphorus-containing radical with the specific structure can release halogen free radical or phosphorus free radical after being heated, so that hydrogen free radical or hydroxyl free radical generated in the use process of the secondary battery can be effectively quenched, the thermal runaway triggering temperature of the battery is further improved, and the occurrence of thermal runaway is delayed.
In some of these embodiments, the halogen comprises at least one of F and Br.
F and Br are strong in electronegativity, especially F electronegativity is strong, and is favorable for reducing a graphite negative electrode to generate a compact LiF-rich inorganic SEI film, so that the decomposition temperature of the SEI film is improved, and the occurrence of thermal runaway of a battery is delayed.
The aryl or the specific phosphorus-containing group not only has good flame retardant effect, but also participates in the formation of a cathode CEI layer, can better protect a cathode interface, prevent transition metal from dissolving out, reduce side reaction and improve the battery performance.
In some of these embodiments, R 4 And R is 5 Each independently selected from any one of an alkoxy group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms substituted with halogen.
In some of these embodiments, the cyclosiloxane compound includes at least one of the following formulas (1 b) and (1 d):
。
In some embodiments, in the electrolyte, the mass ratio of the cyclosiloxane compound is 0.1% -10%.
In some embodiments, in the electrolyte, the mass ratio of the cyclosiloxane compound is 3% -6%.
Further regulate the content of cyclosiloxane compound and fully exert the synergistic interaction.
In some of these embodiments, the components of the electrolyte further include an electrolyte salt and an organic solvent.
In some embodiments, the electrolyte salt satisfies at least one of the following conditions (1) - (2):
(1) In the electrolyte, the concentration of the electrolyte salt is 0.8 moL/L-1.2 moL/L;
(2) The electrolyte salt includes LiPF 6 、LiBF 4 、LiAsF 6 、LiBOB、LiDFOB、LiN(CF 3 SO 2 ) 2 And at least one of lithium bis-fluorosulfonyl imide.
In a second aspect of the present application, there is provided a secondary battery comprising the electrolyte of the first aspect.
In a third aspect of the present application, there is provided an electric device including the secondary battery of the second aspect.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the accompanying drawings. In the drawings:
FIG. 1 is a schematic diagram of one embodiment of a battery cell;
FIG. 2 is an exploded view of FIG. 1;
FIG. 3 is a schematic diagram of an embodiment of a battery pack;
FIG. 4 is an exploded view of FIG. 3;
fig. 5 is a schematic diagram of an embodiment of an electrical device with a battery as a power source.
Reference numerals illustrate:
1. a battery pack; 2. an upper case; 3. a lower box body; 4. a battery cell; 41. a housing; 42. an electrode assembly; 43. a cover plate; 5. and (5) an electric device.
Detailed Description
Embodiments of the technical scheme of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, and are not intended to limit the scope of the present application.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.
In the description of embodiments of the present application, the technical terms "first," "second," and the like are used merely to distinguish between different objects and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated, a particular order or a primary or secondary relationship. In the description of the embodiments of the present application, the meaning of "plurality" is two or more unless explicitly defined otherwise.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
In the present application, the term "alkyl" refers to groups formed by the loss of one hydrogen from an alkane, including straight chain alkyl groups and branched chain alkyl groups, such as methyl groups formed by the loss of one hydrogen from methane; similarly, the term "alkylene" refers to a group formed by the loss of two hydrogens from an alkane, such as methane, which forms a methylene group upon loss of two hydrogens.
In the present application, the "alkyl group having 1 to 10 carbon atoms" may have 1 to 10 carbon atoms, including 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, non-limiting examples include a methyl group, an ethyl group, and an n-propyl group.
The terms "linear alkyl" and "branched alkyl" refer to groups in which carbon atoms are all joined by single carbon-carbon bonds and do not form a ring, and the remaining bonds are all formed by the loss of one hydrogen from an alkane formed by combining the remaining bonds with hydrogen.
In the present application, halogen groups include chlorine, fluorine, bromine, iodine.
As used herein, "aryl" refers to hydrocarbyl groups containing at least one aromatic ring, including non-fused ring aryl groups and fused ring aryl groups. Condensed ring aryl refers to a group formed by connecting two or more aromatic rings through two adjacent ring atoms in common, i.e., a condensed ring.
An aromatic ring refers to a cyclic hydrocarbon compound having aromaticity: namely hydrocarbon compounds having a cyclic ring-closing conjugated system.
In the present application, the "number of ring-forming atoms" means the number of atoms bonded to form a ring, and when the ring is substituted with a substituent, the atoms contained in the substituent are not included in the ring-forming atoms. The same applies to the "number of ring-forming atoms" described below, unless otherwise specified, for example, the number of ring-forming atoms of the benzene ring is 6, and the number of ring-forming atoms of the naphthalene ring is 10.
In one embodiment of the present application, there is provided an electrolyte, wherein the electrolyte comprises a cyclosiloxane compound represented by formula (1):
，
wherein each R 1 And each R 2 Are independently selected from H, halogen, and takeSubstituted or unsubstituted aryl group having 6 to 10 ring-forming atoms, alkyl group having 1 to 10 carbon atoms, halogen-substituted alkyl group having 1 to 10 carbon atoms, andat least one R of a plurality of repeating units of the cyclosiloxane compound 1 Or at least one R 2 Selected from substituted or unsubstituted aryl or +.>；
R 3 Any one selected from an alkylene group having 1 to 5 carbon atoms and an alkylene group having 1 to 5 carbon atoms substituted with halogen; r is R 4 And R is 5 Each independently selected from any one of H, an alkoxy group having 1 to 10 carbon atoms and an alkoxy group having 1 to 10 carbon atoms substituted with halogen, and R 4 And R is 5 Not simultaneously H;
"x" represents the site of attachment, ""represents that atoms at two ends are connected to form a ring, and n is any integer from 3 to 5.
The components of the electrolyte contain cyclosiloxane compounds with specific structures, the cyclosiloxane compounds shown in the formula (1) contain a cyclosiloxane main structure and specific hydrocarbon groups connected to the main structure, on one hand, the cyclosiloxane main structure has higher thermal stability and chemical stability, the cyclosiloxane main structure can undergo a ring-opening reaction when the temperature is increased, byproducts such as LiCX and the like are subjected to real-time targeted passivation, the exothermic side reaction of the cyclosiloxane main structure and the electrolyte is effectively inhibited, the SEI film is subjected to targeted repair, and gel substances can be polymerized when the ring-opening reaction is carried out to a certain extent, and the gel substances adhere to a diaphragm to play a supporting role to inhibit the shrinkage of the isolating film; on the other hand, the chemical stability of the cyclosiloxane compound is further improved by the specific hydrocarbon groups connected to the main structure, and each specific structure is organically combined, so that the electrochemical window of the electrolyte is widened, the thermal runaway critical point of the electrolyte is improved, the thermal runaway trigger temperature of the secondary battery can be improved, the occurrence of thermal runaway is delayed, and the electrochemical window is widened when the electrolyte is applied to the preparation of the secondary battery.
It can be understood that: ""representative" []"atoms at both ends are linked to form a ring, i.e." []"two atoms at both ends of the group shown in the text": an oxygen atom and a silicon atom; in other words, the cyclosiloxane compound includes at least one of the following formulas (1-1) to (1-3):
。
in some embodiments, the substituted or unsubstituted aryl group having 6 to 10 ring members includes at least one of an unsubstituted aryl group having 6 to 10 ring members, an aryl group having 6 to 10 ring members substituted with a C1 to C5 alkyl group, and an aryl group having 6 to 10 ring members substituted with halogen.
In some of these embodiments, the halogen comprises at least one of F and Br.
F and Br are strong in electronegativity, especially F electronegativity is strong, and is favorable for reducing a graphite negative electrode to generate a compact LiF-rich inorganic SEI film, so that the decomposition temperature of the SEI film is improved, and the occurrence of thermal runaway of a battery is delayed.
The saturated hydrocarbon group or aryl group has higher chemical stability, and halogen or the phosphorus-containing group with the specific structure can release halogen free radicals or phosphorus free radicals after being heated, so that hydrogen free radicals or hydroxyl free radicals generated in the use process of the secondary battery can be effectively quenched, the thermal runaway triggering temperature of the battery is further improved, and the occurrence of thermal runaway is delayed.
In some of these embodiments, each R 1 And each R 2 Are each independently selected from H, halogen, substituted or unsubstituted aryl groups having 6 to 8 ring-forming atoms, alkyl groups having 1 to 5 carbon atoms, halogen-substituted alkyl groups having 1 to 5 carbon atoms, andany of (3)One of the two.
In some of these embodiments, each R 1 And each R 2 Are each independently selected from H, halogen, substituted or unsubstituted aryl groups having 6 to 8 ring-forming atoms, straight-chain alkyl groups having 1 to 5 carbon atoms substituted with halogen, andany one of the following.
In some of these embodiments, each R 1 And each R 2 Are each independently selected from H, halogen, phenyl substituted by halogen, straight-chain alkyl having 1 to 3 carbon atoms, straight-chain alkyl substituted by halogen having 1 to 3 carbon atoms andany one of the following.
In some of these embodiments, each R 1 And each R 2 Each independently selected from H, halogen, phenyl substituted with halogen, methyl, ethyl, n-propyl, isopropyl, methyl substituted with halogen, ethyl substituted with halogen, n-propyl substituted with halogen, isopropyl substituted with halogen, andany one of the following.
In some of these embodiments, at least one R in a plurality of repeating units of a cyclosiloxane compound 1 Or at least one R 2 Selected from substituted or unsubstituted aryl groups having 6 to 10 ring members andany one of the following.
In some of these embodiments, at least one R in a plurality of repeating units of a cyclosiloxane compound 1 Or at least one R 2 Selected from substituted or unsubstituted aryl groups having 6 to 8 ring members andany one of the following.
In some of these embodiments, at least one R in the multiple repeating units of the cyclosiloxane compound 1 Or at least one R 2 Is selected from a linear alkyl group having 1 to 5 carbon atoms or a halogen-substituted linear alkyl group having 1 to 5 carbon atoms; at least one other R 1 Or at least one other R 2 Selected from substituted or unsubstituted aryl groups having 6 to 10 ring members andany one of the following.
In some of these embodiments, at least one R in the multiple repeating units of the cyclosiloxane compound 1 Or at least one R 2 Selected from methyl, ethyl, n-propyl, isopropyl, methyl substituted by halogen, ethyl substituted by halogen, n-propyl substituted by halogen or isopropyl substituted by halogen; at least one other R 1 Or at least one other R 2 Selected from phenyl, phenyl substituted by halogen andany one of the following.
In some of these embodiments, R 4 And R is 5 Each independently selected from any one of an alkoxy group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms substituted with halogen.
If a plurality of R's are present in the same molecule 4 Or a plurality of R 5 In the case of (2), each R 4 Each R may be the same or different 5 Or may be the same or different.
In some of these embodiments, "alkoxy" is generally represented by "r-O-", r is an alkyl group having 1 to 5 carbon atoms or an alkyl group having 1 to 5 carbon atoms substituted with halogen.
In some embodiments, r is an alkyl group having 1 to 5 carbon atoms or a straight chain alkyl group having 1 to 5 carbon atoms substituted with halogen.
In some of these embodiments, R 4 And R is 5 Independently selected from any of an alkoxy group having 1 to 3 carbon atoms and an alkoxy group having 1 to 3 carbon atoms substituted with halogenOne of the two.
In other words, r is an alkyl group having 1 to 3 carbon atoms or an alkyl group having 1 to 3 carbon atoms substituted with halogen.
In some embodiments, r is a straight-chain alkyl group having 1 to 3 carbon atoms or a straight-chain alkyl group having 1 to 3 carbon atoms substituted with halogen.
In some embodiments, r is any one of methyl, ethyl, n-propyl, isopropyl, methyl substituted with halogen, ethyl substituted with halogen, n-propyl substituted with halogen, and isopropyl substituted with halogen.
In some embodiments, the cyclosiloxane compound comprises at least one of the following formulas (1 a) - (1 f):
。
the cyclosiloxane compound represented by the formula (1) of the present application is a compound having a known structure in the art or a compound obtainable according to the description of the prior art. For example, formula (1 a) is 3, 5-trimethyl-1, 3, 5-tris (3, 3-trifluoropropyl) cyclotrisiloxane, CAS number: 2374-14-3; formula (1 e) is 2,4,6, 8-tetramethyl-2, 4,6, 8-tetrakis (3, 3-trifluoropropyl) cyclotetrasiloxane, CAS number: 429-67-4; the formula (1 b), the formula (1 c), the formula (1 d) and the formula (1 f) can be obtained by inquiring a chemical reagent net or a literature or a patent, and are not described herein.
In some embodiments, the mass ratio of the cyclosiloxane compound in the electrolyte is 0.1% -10%.
In some embodiments, the mass ratio of the cyclosiloxane compound in the electrolyte is 3% -6%.
Further regulate the content of cyclosiloxane compound and fully exert the synergistic interaction.
In the foregoing "0.1% -10%", the values include the minimum value and the maximum value of the range, and each value between the minimum value and the maximum value, and specific examples include, but are not limited to, the point values in the embodiments and the following point values: "0.1%, 0.2%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9%, 10%; or a range of any two values, for example: 0.1-10%, 0.1-8%, 0.1-9%, 0.1-7%, 0.1-6%, 0.1-5%, 0.1-4%, 0.1-3%, 0.1-2%, 0.1-1%, 1-10%, 1-8%, 1-9%, 1-7%, 1-6%, 1-5%, 1-4%, 1-3%, 1-2%, 2-10%, 2-8%, 2-9%, 2-7%, 2-6%, 2-5%, 2-4%, 2-3%, 3-10%, 3-8%, 3-9%, 3-7%, 3-6%, 3-5%.
In some of these embodiments, the components of the electrolyte further include an electrolyte salt and an organic solvent.
In some of these embodiments, the concentration of the electrolyte salt is 0.8moL/L to 1.2moL/L.
The electrolyte salt may be selected from electrolyte salts commonly used in the art, such as lithium ion electrolyte salts.
As examples, lithium ion electrolyte salts include, but are not limited to: lithium hexafluorophosphate (LiPF) 6 ) Lithium tetrafluoroborate (LiBF) 4 ) Lithium perchlorate (LiClO) 4 ) Lithium hexafluoroarsenate (LiAsF) 6 ) Lithium bis (fluorosulfonyl) imide (LiLSI), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalato borate (LiDFOB), lithium difluorooxalato borate (LiBOB), lithium difluorophosphate (LiPO) 2 F 2 ) Lithium difluorodioxalate phosphate (LiDFOP), lithium bis (trifluoromethylsulfonyl) imide (LiN (CF) 3 SO 2 ) 2 ) And one or more of lithium tetrafluorooxalate phosphate (LiTFOP).
In some of these embodiments, the electrolyte salt comprises LiPF 6 、LiBF 4 、LiAsF 6 、LiBOB、LiDFOB、LiN(CF 3 SO 2 ) 2 And at least one of lithium bis-fluorosulfonyl imide.
In some of these embodiments, the organic solvent comprises at least one of a carbonate-based solvent, a carboxylate-based solvent, an ether-based solvent, a nitrile-based solvent, and a phosphazene-based solvent.
In some of these embodiments, the ethereal solvent comprises a fluoroether solvent.
In some embodiments, the organic solvent may be selected from one or more of fluoroethylene carbonate (FEC), ethylene Carbonate (EC), propylene Carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl Propyl Carbonate (MPC), ethylene Propyl Carbonate (EPC), butylene Carbonate (BC), methyl Formate (MF), methyl Acetate (MA), ethyl Acetate (EA), propyl Acetate (PA), 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether, methyl Propionate (MP), ethyl Propionate (EP), propyl Propionate (PP), methyl Butyrate (MB), ethyl Butyrate (EB), 1, 4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl sulfone (EMS), and diethyl sulfone (ESE).
In some of these embodiments, the organic solvent comprises at least one of a carbonate-based solvent, a carboxylate-based solvent, and a fluoroether-based solvent.
In some of these embodiments, the organic solvent includes carbonate solvents, carboxylate solvents, and fluoroether solvents.
In some embodiments, the mass ratio of the carbonate-based solvent, the carboxylic acid-based solvent and the fluorine-containing ether-based solvent is (1-3): 2-8): 1-3.
In some embodiments, the electrolyte further optionally includes an additive. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives capable of improving certain properties of the battery, such as additives that improve the overcharge performance of the battery, additives that improve the high or low temperature performance of the battery, and the like.
In one embodiment of the present application, a secondary battery is provided that includes the electrolyte of the first aspect.
In some of these embodiments, the secondary battery further includes a positive electrode tab, a negative electrode tab, and a separator.
In the present application, the positive electrode sheet, the negative electrode sheet and the separator may be used in a system commonly used in the art, and the positive electrode sheet, the negative electrode sheet and the separator are exemplified as follows.
Positive plate: the positive plate comprises a current collector and a positive active layer loaded on the surface of the current collector.
The composition of the positive electrode active layer includes a positive electrode active material. The positive electrode active material may be selected from positive electrode active materials commonly used in the art, including but not limited to: positive electrode active material of lithium ion battery, positive electrode active material of sodium ion battery and positive electrode active material of potassium ion battery.
The positive electrode active material of the lithium ion battery, the positive electrode active material of the sodium ion battery and the positive electrode active material of the potassium ion battery are hereinafter respectively abbreviated as lithium ion active material, sodium ion active material and potassium ion active material.
Further, as an example, the lithium ion active material may include at least one of the following materials: olivine structured lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material may be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (e.g., liCoO) 2 ) Lithium nickel oxide (e.g. LiNiO) 2 ) Lithium manganese oxide (e.g. LiMnO 2 、LiMn 2 O 4 ) Lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., liNi) 1/3 Co 1/3 Mn 1/3 O 2 (also abbreviated as NCM 333), liNi 0.5 Co 0.2 Mn 0.3 O 2 (also abbreviated as NCM 523), liNi 0.5 Co 0.25 Mn 0.25 O 2 (also abbreviated as NCM 211), liNi 0.6 Co 0.2 Mn 0.2 O 2 (also abbreviated as NCM 622), liNi 0.8 Co 0.1 Mn 0.1 O 2 (abbreviated as NCM 811), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ) And at least one of its modified compounds and the like. Containing olivine structuresExamples of lithium phosphate salts may include, but are not limited to, lithium iron phosphate (e.g., liFePO 4 Simply called LFP) lithium manganese phosphate (e.g. LiMnPO 4 ) At least one of lithium iron manganese phosphate. In any embodiment of the present application, the lithium ion active material has the formula: liFe x Mn (1-x) PO 4 X is any number from 0 to 1.
It can be appreciated that when x takes 0, liFe x Mn (1-x) PO 4 Namely LiMnPO 4 Lithium manganese phosphate, liFe when x is 1 x Mn (1-x) PO 4 I.e. LiFePO 4 Lithium iron phosphate (LFP).
It should be noted that, the lithium content in the above-mentioned example positive electrode material refers to the content of the positive electrode material when not in use, the battery will repeatedly act as electricity during the use process, the Li in the positive electrode active material will change during the charge and discharge process, i.e. the molar index of the Li in the positive electrode active material in the battery product will not be kept at 1 all the time, and will change; further, the variation range may be (0 to 1.2).
For example LiFe x Mn (1-x) PO 4 Can be further represented as Li y Fe x Mn (1-x) PO 4 Y is 0 to 1.1.
For example for ternary materials Li y (Ni a Co b Mn c ) 1-d M d O 2-x A x Y is 0.2-1.2, a+b+c=1, d is 0-1, x is 0-1<2; m is one or more of Zr, sr, B, ti, mg, sn and Al, A is one or more of S, N, F, cl, br and I.
The battery can be accompanied with the deintercalation and consumption of Li in the charging and discharging process, the molar contents of Li are different when the battery is discharged to different states, and the limitation on y comprises the molar contents of Li in different charging and discharging states of the battery; further, the battery voltage is typically between 2-5V.
In any embodiment of the present application, in the positive electrode active layer, the mass ratio of the positive electrode active material is 70% to 99.8%.
In any embodiment of the present application, the components of the positive electrode active layer further include a conductive agent and a binder.
Taking the electrode sheet as an anode as an example, the conductive agent may be a conductive agent commonly used in the art, including but not limited to: at least one of graphite, carbon nanotubes, nanofibers, carbon black, and graphene. Specifically, the conductive material is at least one selected from SP, KS-6, acetylene black, ketjen black ECP with branched structure, SFG-6, vapor grown carbon fiber VGCF, carbon nanotube CNTs, graphene and composite conductive agent thereof.
The binder of the binder may be at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, hydrogenated nitrile rubber, styrene Butadiene Rubber (SBR), polyacrylic acid (PAA), sodium Polyacrylate (PAAs), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium Alginate (SA), polymethacrylic acid (PMAA), carboxymethyl chitosan (CMCS), and fluoroacrylate resin.
Optionally, in the positive electrode active layer, the mass ratio of the conductive agent is 1% -20%.
Optionally, in the positive electrode active layer, the mass ratio of the binder is 1% -10%.
In some embodiments, the thickness of the positive electrode active layer is 30 μm to 200 μm.
In any embodiment of the present application, the current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum foil may be used. The composite current collector may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material base layer. The composite current collector may be formed by forming a metal material on a polymeric material substrate.
In some of these embodiments, the metallic material is selected from any one of aluminum, aluminum alloy, nickel alloy, titanium alloy, silver, and silver alloy.
In some of these embodiments, the polymeric material substrate comprises at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE).
In any embodiment of the present application, the positive electrode sheet may be prepared by: dispersing the components for preparing the positive plate in a solvent to form positive electrode slurry; and (3) coating the positive electrode slurry on a current collector, and drying, cold pressing and other working procedures to obtain the positive electrode plate. The solid content of the positive electrode slurry is 40 wt% -80% by weight, the viscosity at room temperature is adjusted to 5000 mPa.s-25000 mPa.s, the positive electrode slurry is coated on the surface of a positive electrode current collector, and the positive electrode sheet is formed after drying and cold pressing by a cold rolling mill.
Further, the solvent includes N-methylpyrrolidone.
In some of these embodiments, the positive electrode active layer contained in the positive electrode sheet has an areal density of 0.02g/cm 2 ~0.08g/cm 2 。
Areal density = mass of positive electrode active layer/positive electrode sheet area.
Negative electrode plate: the negative electrode sheet may be a negative electrode sheet system of various secondary batteries commonly used in the art, and is exemplified by, but not limited to, lithium ion secondary batteries and lithium metal secondary batteries as follows.
In some of these embodiments, the secondary battery is a lithium metal secondary battery, and the negative electrode sheet may be a negative electrode sheet that can be used in a lithium metal battery as known in the art.
In some embodiments, the negative electrode sheet is directly a lithium-containing metal sheet.
In another embodiment, the negative electrode sheet includes a lithium-containing metal layer and a conductive layer that are stacked.
Further, the lithium-containing technique in the lithium-containing metal sheet and the lithium-containing metal layer may be lithium metal, or may be an alloy of lithium metal and other metal or nonmetal elements.
Further, the other metal includes at least one of tin (Sn), zinc (Zn), aluminum (Al), magnesium (Mg), silver (Ag), gold (Au), gallium (Ga), indium (In), and foil (Pt); the nonmetallic element includes at least one of boron (B), carbon (C) and silicon (Si).
In some of these embodiments, the conductive layer may be a copper foil.
In any embodiment of the present application, the above-described negative electrode sheet may be prepared by: the lithium-containing metal sheet is directly pressed to obtain the negative electrode sheet, or the lithium-containing metal layer and the conductive layer are laminated and pressed to obtain the negative electrode sheet.
In some of these embodiments, the secondary battery is a lithium ion secondary battery, and the negative electrode sheet may be a negative electrode sheet that can be used for lithium ion secondary batteries as known in the art.
In some of these embodiments, the negative electrode sheet includes a current collector and a negative electrode active layer supported on the surface of the current collector.
The composition of the anode active layer includes an anode active material.
The negative electrode active material may be a negative electrode active material commonly used in the present application.
In any embodiment of the present application, the negative electrode active material includes at least one of mesophase carbon microspheres, graphite, glassy carbon, carbon nanotubes, carbon-carbon composite materials, carbon fibers, hard carbon, soft carbon, silicon-based materials, tin-based materials, magnesium-based materials, and iron-based materials.
Alternatively, specific examples of the above-described anode active material include, but are not limited to: at least one of mesophase carbon microspheres, natural graphite, artificial graphite, graphene, glassy carbon, carbon nanotubes, carbon fibers, hard carbon, soft carbon, iron oxide, tin oxide, silicon oxide, magnesium oxide, silicon carbon composites, lithium metal and lithium metal alloys.
In any embodiment of the present application, the mass ratio of the negative electrode active material in the negative electrode active layer is 70% to 100%.
In any embodiment of the present application, the components of the negative electrode active layer further include a negative electrode conductive agent and a negative electrode binder.
In any embodiment of the present application, the above-mentioned negative electrode conductive agent may use conductive materials commonly used in the art, including but not limited to: at least one of graphite, carbon nanotubes, nanofibers, carbon black, and graphene. Specifically, the conductive material is at least one selected from SP, KS-6, acetylene black, ketjen black ECP with branched structure, SFG-6, vapor grown carbon fiber VGCF, carbon nanotube CNTs, graphene and composite conductive agent thereof.
The weight ratio of the negative electrode conductive agent in the negative electrode active layer is 0-20wt% based on the total weight of the negative electrode active layer.
The negative electrode binder may be at least one binder commonly used in the art, and may be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium Polyacrylate (PAAs), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium Alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).
The weight ratio of the anode binder in the anode active layer is 0 to 30wt% based on the total weight of the anode active layer.
In any embodiment of the present application, the anode active layer may further optionally include other auxiliary agents, for example, a thickener such as sodium carboxymethyl cellulose (CMC-Na) or the like. The weight ratio of other auxiliary agents in the anode active layer is 0-15 wt% based on the total weight of the anode active layer.
In any embodiment of the present application, the current collector in the negative electrode sheet may be a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used.
The composite current collector may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material base layer. The composite current collector may be formed by forming a metal material on a polymeric material substrate.
In some of these embodiments, the metallic material is selected from any one of aluminum, aluminum alloy, nickel alloy, titanium alloy, silver, and silver alloy.
In some of these embodiments, the polymeric material substrate comprises at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE).
In any embodiment of the present application, the negative electrode sheet may be prepared by: dispersing the above components for preparing a negative electrode sheet, such as a negative electrode active material, a conductive agent, a binder, and any other components, in a solvent to form a negative electrode slurry; and coating the negative electrode slurry on a negative electrode current collector, and obtaining the negative electrode plate after the procedures of drying, cold pressing and the like.
In some of these embodiments, the above solvents include, but are not limited to: and (3) water.
In some of these embodiments, the solid content of the negative electrode slurry is 30 wt% to 70% by weight, and the viscosity at 25 ℃ is adjusted to 2000mpa·s to 10000mpa·s.
In some of these embodiments, the surface density of the anode active layer contained in the anode sheet is 0.005g/cm 2 ~0.05g/cm 2 。
Isolation film: the isolating film is arranged between the positive plate and the negative plate.
The type of the separator is not particularly limited, and any known porous separator having good chemical stability and mechanical stability can be used.
In some embodiments, the material of the isolating film may be at least one selected from glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
Alternatively, the separator may be a single-layer film or a multi-layer composite film. Further, when the separator is a multilayer composite film, the materials of the respective layers may be the same or different.
In some of these embodiments, the thickness of the barrier film is 2 μm to 15 μm; optionally, the thickness of the isolation film is 2-13 μm.
The shape of the secondary battery of the present application may be a cylindrical shape, a square shape, or any other shape. For example, fig. 1 is a battery cell 4 of a secondary battery of a square structure as an example.
In some embodiments, referring to fig. 2, the housing may include a shell 41 and a cover plate 43. The housing 41 may include a bottom plate and a side plate connected to the bottom plate, where the bottom plate and the side plate enclose a receiving chamber. The housing 41 has an opening communicating with the accommodation chamber, and the cover plate 43 can be provided to cover the opening to close the accommodation chamber.
The positive electrode sheet, the negative electrode sheet, and the separator may be formed into the electrode assembly 42 through a winding process or a lamination process. The electrode assembly 42 is packaged in the receiving chamber. The electrolyte is impregnated in the electrode assembly 42. The number of electrode assemblies 42 included in the battery cell 4 may be one or more, and may be adjusted according to the need.
The secondary battery includes one or more battery cells 4.
The secondary battery may be a battery module or a battery pack; the battery module or the battery pack includes at least one battery cell. The number of battery cells included in the battery module may be one or more, and one skilled in the art may select an appropriate number according to the application and capacity of the battery module.
Fig. 3 and 4 are battery packs 1 as an example. The battery pack 1 includes a battery case and one or more battery cells 4 provided in the battery case. The battery box comprises an upper box body 2 and a lower box body 3, wherein the upper box body 2 can be covered on the lower box body 3, and a closed space for the battery cells 4 is formed.
The plurality of battery cells 4 may be arranged in the battery box in any manner.
The application also provides an electric device which comprises the secondary battery.
Further, in the above-described power consumption device, the secondary battery may exist in the form of a battery cell or may exist in the form of a battery pack further assembled.
The battery or the battery pack assembled by the battery can be used as a power source of an electric device and also can be used as an energy storage unit of the electric device.
The above-mentioned electric device may be, but is not limited to, a mobile device, an electric vehicle, an electric train, a ship, a satellite, an energy storage system, or the like.
Mobile devices include, but are not limited to: cell phones, notebook computers, etc., electric vehicles include, but are not limited to: pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, and the like.
Fig. 5 is an electric device 5 as an example. The electric device 5 is a pure electric vehicle, a hybrid electric vehicle or a plug-in hybrid electric vehicle. In order to meet the high power and high energy density requirements of the secondary battery of the power consuming device 5, a battery pack form may be employed.
As another example, the power consumption device may be a mobile phone, a tablet computer, a notebook computer, or the like. The device is generally required to be light and thin, and a secondary battery can be used as a power source.
The invention will be described in connection with specific embodiments, but the invention is not limited thereto, and it will be appreciated that the appended claims outline the scope of the invention, and those skilled in the art, guided by the inventive concept, will appreciate that certain changes made to the embodiments of the invention will be covered by the spirit and scope of the appended claims.
The following are specific examples.
Example 1
S1, preparation of lithium ion battery
(1) Preparation of electrolyte: in an argon-filled glove box (water content < 10ppm, oxygen content < 1 ppm), the electrolyte salt LiPF was prepared 6 Adding into an organic solvent, wherein the organic solvent is a mixed solution of ethylene carbonate and dimethyl carbonate, the mass content of the ethylene carbonate is 20wt% based on the total mass of the organic solvent, and adding the cyclosiloxane compound (1 b) after the lithium salt is completely dissolved. And uniformly stirring to obtain the electrolyte with the electrolyte salt concentration of 1.0mol/L and the mass ratio of the cyclosiloxane compound of 5%.
Wherein, in the electrolyte, the mass ratio of the cyclosiloxane compound is recorded as M1, and the specific application is shown in Table 1.
Wherein, the components in the electrolyte and the proportion thereof can be obtained by analysis by adopting the common analysis means in the field, and non-limiting examples include: and (3) quantitatively analyzing and detecting by adopting organic component weather chromatography, and confirming the structure and the content of each component in the electrolyte.
(2) Preparation of negative electrode plate
The preparation method comprises the steps of configuring and dispersing negative electrode active substances, namely natural graphite, conductive carbon black SP, thickener CMC and binder SBR in solvent deionized water according to a mass ratio of 96:1:1:2, and uniformly mixing to obtain negative electrode slurry; uniformly coating the negative electrode slurry on the negative electrodeA copper foil of the polar current collector; drying, cold pressing to form a negative electrode active layer, dividing into strips, and cutting to obtain a negative electrode plate, wherein the surface density of the negative electrode plate is 46.67mg/cm 2 。
(3) Preparation of positive plate
The positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2 The preparation method comprises the steps of preparing and dispersing conductive carbon black SP and a binder PVDF into a solvent NMP (N-methylpyrrolidone) according to a mass ratio of 96:2:2, uniformly mixing to obtain positive electrode slurry, uniformly coating the positive electrode slurry on a positive electrode current collector aluminum foil, drying, cold pressing to form a positive electrode active layer, and slitting and cutting to obtain a positive electrode plate, wherein the surface density of the positive electrode plate is 73.3mg/cm 2 。
(4) Isolation film: polypropylene film (PP) is selected.
(5) Assembling a lithium ion battery: and sequentially stacking the prepared positive plate, the PP diaphragm and the negative plate, enabling the diaphragm to be positioned between the positive electrode and the negative electrode, winding to obtain a bare cell, welding the tab, placing the tab in an outer package, injecting the prepared electrolyte into the dried cell, standing, and forming to obtain the lithium ion battery.
S2, performance test of the lithium ion battery:
(1) And (3) hot box test:
fully charging the battery cell at 1/3C, arranging a temperature sensing wire on the large surface of the battery cell to monitor the temperature change of the battery cell in the test process, arranging a voltage sensing wire on the battery cell pole to monitor the voltage change of the battery cell in the test process, arranging a temperature sensing wire on the oven to monitor the temperature change in the oven, and raising the temperature to 55 ℃ and keeping for 2 hours; and keeping the temperature rise speed at 5 ℃ per minute for 30 minutes at 5 ℃ per time until the thermal runaway of the battery cell or the temperature reaches 200 ℃, recording the thermal runaway temperature, recording as T1, and if the temperature reaches 200 ℃, preserving the temperature for 3 hours, wherein the experiment is stopped under one of the two conditions.
And weighing the mass of the battery cell before and after the experiment, calculating mass loss according to the following formula, and auxiliary evaluating the performance of the battery cell hot box.
Mass loss= (m 1-m 2)/m1×100%, where m1 and m2 are the cell mass before and after the experiment, respectively.
(2) Electrochemical window testing
Linear Sweep Voltammetry (LSV) test: the electrochemical analysis instrument CHI660E is adopted for testing, the lithium ion battery prepared in the above is scanned to obtain a voltammogram LSV, specifically, the voltammogram LSV is scanned from an open-circuit voltage to 6V at a scanning rate of 0.2 mV/s, the upper limit value of an electrochemical window is obtained by analyzing the voltammogram LSV and is recorded as H, and the higher the upper limit value of the electrochemical window is, the higher the stability of the electrolyte is, and the wider the application range is.
The specific results are shown in Table 1.
Examples 2 to 6
Examples 2 to 6 are basically the same as example 1, except that: in the preparation of the electrolyte in the step (1), the kind of the cyclosiloxane compound is different from that in example 1.
Other steps were carried out under the same conditions as in example 1, and the test results are shown in Table 1.
Example 7
Example 7 is substantially the same as example 1, except that: in the preparation of the electrolyte in the step (1), the organic solvent is a mixed solution of Ethylene Carbonate (EC), dimethyl carbonate (DMC) and 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether (TTE), the mass ratio of Ethylene Carbonate (EC), dimethyl carbonate (DMC) and 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether (TTE) was 20%, 60% and 20% in this order, based on the total mass of the organic solvent.
Other steps were carried out under the same conditions as in example 1, and the test results are shown in Table 1.
Examples 8 to 11
Examples 8 to 11 are basically the same as example 7, except that: in the preparation of the electrolyte in the step (1), the kind of the cyclosiloxane compound is different from that in example 7.
Other steps were carried out under the same conditions as in example 7, and the test results are shown in Table 1.
Example 12
Example 12 is substantially the same as example 7, except that: in the preparation of the electrolyte in the step (1), the electrolyte salt is LiPF with the mass ratio of 1:1 6 And LiFSI, the mass of cyclosiloxane compound accounts forThe ratio was 1%.
Other steps were carried out under the same conditions as in example 7, and the test results are shown in Table 1.
Examples 13 to 16
Examples 13 to 16 are basically the same as example 12, except that: in the preparation of the electrolyte in the step (1), the kind of the cyclosiloxane compound is different from that in example 7.
Other steps were carried out under the same conditions as in example 12, and the test results are shown in Table 1.
Example 17
Example 17 is substantially the same as example 12 except that: in the preparation of the electrolyte in the step (1), the mass ratio of the cyclosiloxane compound is 5%.
Other steps were carried out under the same conditions as in example 12, and the test results are shown in Table 1.
Examples 18 to 21
Examples 18 to 21 are basically the same as example 17, except that: in the preparation of the electrolyte in the step (1), the kind of the cyclosiloxane compound is different from that in example 17.
Other steps were carried out under the same conditions as in example 17, and the test results are shown in Table 1.
Example 22
Example 22 is substantially the same as example 12, except that: in the preparation of the electrolyte in the step (1), the mass ratio of the cyclosiloxane compound is 8%.
Other steps were carried out under the same conditions as in example 12, and the test results are shown in Table 1.
Examples 23 to 26
Examples 23 to 26 are basically the same as example 22, except that: in the preparation of the electrolyte in the step (1), the kind of the cyclosiloxane compound is different from that in example 22.
Other steps were carried out under the same conditions as in example 22, and the test results are shown in Table 1.
Examples 27 to 28
Examples 27 to 28 are substantially the same as example 12, except that: in the preparation of the electrolyte in the step (1), the mass ratio of the cyclic siloxane compound in the embodiment 27 is 0.5%, and the mass ratio of the cyclic siloxane compound in the embodiment 27 is 10%.
Other steps were carried out under the same conditions as in example 12, and the test results are shown in Table 1.
Comparative example 1
Comparative example 1 is substantially the same as example 1 except that: in the preparation of the electrolyte in the step (1), a cyclosiloxane compound is not added.
Other steps were carried out under the same conditions as in example 1, and the test results are shown in Table 1.
Comparative example 2
Comparative example 2 is substantially the same as example 1 except that: in the preparation of the electrolyte in the step (1), no cyclosiloxane compound is added, the organic solvent is a mixed solution of Ethylene Carbonate (EC), dimethyl carbonate (DMC) and 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether (TTE), the mass ratio of Ethylene Carbonate (EC), dimethyl carbonate (DMC) and 1, 2-tetrafluoroethyl-2, 3-tetrafluoropropyl ether (TTE) was 20%, 60% and 20% in this order, based on the total mass of the organic solvent.
Other steps were carried out under the same conditions as in example 1, and the test results are shown in Table 1.
Comparative example 3
Comparative example 3 is substantially the same as comparative example 2 except that: in the preparation of the electrolyte in the step (1), the electrolyte salt is LiPF with the mass ratio of 1:1 6 And mixed salts of LiFSI.
Other steps were carried out under the same conditions as in comparative example 2, and the test results are shown in Table 1.
Comparative example 4
Comparative example 4 is substantially the same as example 1 except that: in the preparation of the electrolyte in the step (1), the cyclosiloxane compound is shown as a formula (2 a).
Other steps were carried out under the same conditions as in example 1, and the test results are shown in Table 1.
The structure of the cyclosiloxane compound used in each example and comparative example is shown below:
/>
the main parameters and test results for each example and comparative example are shown in Table 1.
TABLE 1
Wherein "/" represents the absence of the substance or the parameter.
The data in Table 1 are analyzed, the test results of comparative examples 1 to 28 and comparative examples 1 to 4 are compared, and further, the comparative analysis examples 1 to 6 show that the electrolyte provided by the application can widen the electrochemical window and simultaneously raise the thermal runaway critical point, and when the electrolyte is applied to the preparation of secondary batteries, the thermal runaway trigger temperature of the secondary batteries can be raised, the occurrence of thermal runaway is delayed, and the electrochemical window is widened.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. The scope of the application is therefore intended to be covered by the appended claims, and the description and drawings may be interpreted in accordance with the contents of the claims.

Claims (14)

1. An electrolyte is characterized by comprising a cyclosiloxane compound shown in a formula (1):
，
wherein each R 1 And each R 2 Are each independently selected from H, halogen, substituted or unsubstituted aryl groups having 6 to 10 ring-forming atoms, alkyl groups having 1 to 10 carbon atoms, halogen-substituted alkyl groups having 1 to 10 carbon atoms, andat least one R of a plurality of repeating units of the cyclosiloxane compound 1 Or at least one R 2 Selected from substituted or unsubstituted aryl or +.>；
R 3 Any one selected from an alkylene group having 1 to 5 carbon atoms and an alkylene group having 1 to 5 carbon atoms substituted with halogen; r is R 4 And R is 5 Each independently selected from any one of H, an alkoxy group having 1 to 10 carbon atoms and an alkoxy group having 1 to 10 carbon atoms substituted with halogen, and R 4 And R is 5 Not simultaneously H;
"x" represents the site of attachment, ""represents that atoms at two ends are connected to form a ring, and n is any integer from 3 to 5.
2. The electrolyte of claim 1 wherein the halogen comprises at least one of F and Br.
3. The electrolyte of claim 1 wherein R 4 And R is 5 Each independently selected from any one of an alkoxy group having 1 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms substituted with halogen.
4. The electrolyte according to any one of claims 1 to 3, wherein R 4 And R is 5 Each independently selected from any one of an alkoxy group having 1 to 3 carbon atoms and an alkoxy group having 1 to 3 carbon atoms substituted with halogen.
5. The electrolyte according to any one of claims 1 to 3, wherein the cyclosiloxane compound comprises at least one of the following formulas (1 b) and (1 d):
。
6. the electrolyte according to any one of claims 1 to 3, wherein the mass ratio of the cyclosiloxane compound in the electrolyte is 0.1% -10%.
7. The electrolyte according to any one of claims 1 to 3, wherein the mass ratio of the cyclosiloxane compound in the electrolyte is 3% -6%.
8. The electrolyte according to any one of claims 1 to 3, wherein the electrolyte further comprises an electrolyte salt and an organic solvent.
9. The electrolyte according to claim 8, wherein the electrolyte salt satisfies at least one of the following conditions (1) to (2):
(1) In the electrolyte, the concentration of the electrolyte salt is 0.8 moL/L-1.2 moL/L;
(2) The electrolyte salt includes LiPF 6 、LiBF 4 、LiAsF 6 、LiBOB、LiDFOB、LiN(CF 3 SO 2 ) 2 And lithium bis (fluorosulfonyl) imide One less.
10. The electrolyte of claim 8 wherein the organic solvent comprises at least one of a carbonate-based solvent, a carboxylate-based solvent, an ether-based solvent, a nitrile-based solvent, and a phosphazene-based solvent.
11. The electrolyte of claim 8 wherein the organic solvent comprises a carbonate-based solvent, a carboxylate-based solvent, and a fluoroether-based solvent.
12. The electrolyte according to claim 11, wherein the mass ratio of the carbonate-based solvent, the carboxylic acid-based solvent and the fluoroether-based solvent is (1-3): 2-8): 1-3.
13. A secondary battery comprising the electrolyte according to any one of claims 1 to 12.
14. An electric device, characterized in that the electric device comprises the secondary battery according to claim 13.
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张宏坤: "《反应型含磷阻燃固化剂合成工艺及阻燃环氧树脂材料研发》", 中国矿业大学出版社, pages: 3 - 4 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117577945A (en) * 2024-01-16 2024-02-20 宁德时代新能源科技股份有限公司 Electrolyte and secondary battery

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