CN117673467A - Electrolyte and battery comprising same - Google Patents

Electrolyte and battery comprising same Download PDF

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Publication number
CN117673467A
CN117673467A CN202211098340.3A CN202211098340A CN117673467A CN 117673467 A CN117673467 A CN 117673467A CN 202211098340 A CN202211098340 A CN 202211098340A CN 117673467 A CN117673467 A CN 117673467A
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electrolyte
compound
substituted
unsubstituted
dinitrile
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王海
李素丽
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Zhuhai Cosmx Battery Co Ltd
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Zhuhai Cosmx Battery Co Ltd
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Priority to CN202211098340.3A priority Critical patent/CN117673467A/en
Publication of CN117673467A publication Critical patent/CN117673467A/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
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Secondary Cells (AREA)

Abstract

The invention provides an electrolyte and a battery comprising the electrolyte, wherein the functional additive in the electrolyte comprises a dinitrile compound, a trinitrile compound and a catalyst containing-Si (CN) 3 The functional group silicon nitrile compound and the boron-containing lithium salt compound can jointly act on the surface of the positive electrode to form a composite electrolyte membrane, so that the positive electrode active material is effectively protected, meanwhile, the electrolyte is prevented from being oxidized and decomposed, and the stability of the positive electrode active material is improved.

Description

Electrolyte and battery comprising same
Technical Field
The invention relates to an electrolyte and a battery comprising the same, and belongs to the technical field of lithium ion batteries.
Background
Lithium ion batteries are rechargeable batteries that operate primarily by virtue of lithium ions moving between a positive electrode and a negative electrode. During charge and discharge, li + To-and-fro intercalation and deintercalation between two electrodes: specifically, during charging, li + De-intercalation from the positive electrode, and embedding the negative electrode into the electrolyte, wherein the negative electrode is in a lithium-rich state; the opposite is true when discharging. Lithium ion batteries have been widely used in various electronic products because of their advantages such as high specific energy density and long cycle life, and have been widely used in electric vehicles, various electric tools, and energy storage devices in recent years.
Along with the improvement of the living standard of people and the trend of better life, higher requirements are also put on the energy density of the battery. In order to increase the energy density of the battery, it is a common path to further increase the voltage of the positive electrode material of the lithium ion battery. However, as the limiting voltage of the positive electrode material increases, the gram capacity of the positive electrode material increases gradually, and the high temperature performance of the battery deteriorates seriously, and the long cycle life cannot be ensured. Especially under high voltage (> 4.5V), the volume of the positive electrode material expands and causes serious cracks in the long-term cyclic charge and discharge process, electrolyte enters the positive electrode material to damage the structure of the positive electrode material, and meanwhile, the release of active oxygen further accelerates the oxidative decomposition of the electrolyte. In addition, the protective film on the surface of the negative electrode is also continuously damaged, and finally the problems of serious attenuation of the battery capacity and the like are caused.
Disclosure of Invention
The invention aims to provide electrolyte and a battery comprising the electrolyte, which can solve the problems of volume expansion of a positive electrode material in the battery under high voltage and continuous release of active oxygen to oxidize the electrolyte, and remarkably improve the high-temperature cycle performance and high-temperature storage performance of the battery and simultaneously improve the safety performance of the battery under high temperature.
The invention aims at realizing the following technical scheme:
an electrolyte comprising an organic solvent, an electrolyte lithium salt, and a functional additive;
the functional additive comprises dinitrile compound, trinitrile compound and Si (CN) 3 Functional group silicon nitrile compound and boron-containing lithium salt compound.
According to an embodiment of the present invention, the alloy contains-Si (CN) 3 The functional group silicon nitrile compound is selected from at least one of compounds shown in a formula 1:
in the formula (1), R 1 Selected from hydrogen, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl; in the case of substitution, the substituents are halogen, cyano, alkyl.
According to an embodiment of the present invention, in formula (1), R 1 Selected from hydrogen, cyano, substituted or unsubstituted C 1-6 Alkyl, substituted or unsubstituted C 2-6 Alkenyl, substituted or unsubstituted C 6-12 An aryl group; in the case of substitution, the substituents are halogen, cyano, C 1-6 An alkyl group.
According to an embodiment of the present invention, in formula (1), R 1 Selected from hydrogen, cyano, substituted or unsubstituted C 1-3 Alkyl, substituted or unsubstituted C 2-4 Alkenyl, substituted or unsubstituted C 6-8 An aryl group; in the case of substitution, the substituents are halogen, cyano, C 1-3 An alkyl group.
According to an embodiment of the present invention, the alloy contains-Si (CN) 3 The functional group silicon nitrile compound is selected from at least one of the following compounds A1-A11:
according to an embodiment of the present invention, the alloy contains-Si (CN) 3 The functional group silacrylates may be prepared by methods known in the art or may be commercially available.
According to an embodiment of the present invention, the alloy contains-Si (CN) 3 The functional group-containing silicon nitrile compound is added in an amount of 0.5wt% to 2wt%, for example, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt% or 2.0wt% based on the total weight of the electrolyte.
According to an embodiment of the present invention, the dinitrile compound is selected from at least one of succinonitrile, adiponitrile, glutaronitrile, terephthalonitrile, fumaric dinitrile, cyclohexane-1, 4-dinitrile, 1, 2-bis (cyanoethoxy) ethane, suberonitrile, 4-fluorophthalonitrile, 2-cyanoethyl ether, 1-ethyl-3-methylimidazole dicyan methylene salt, 3' -iminodiproponitrile, azobisisobutyronitrile.
According to an embodiment of the invention, the dinitrile compound is added in an amount of 2.0wt% to 3.0wt%, for example 2.0wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt% or 3.0wt% based on the total weight of the electrolyte.
According to an embodiment of the present invention, the tri-nitrile compound is at least one selected from the group consisting of 1,2, 3-tris (2-cyanooxy) propane, 1,3, 6-hexanetrinitrile, 2-amino-1, 3-tricyano-1-propene, tris (2-cyanoethyl) borate, tris (2-cyanoethyl) phosphine.
According to an embodiment of the present invention, the tri-nitrile compound is added in an amount of 1.0wt% to 2.0wt%, for example, 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt% or 2.0wt% based on the total weight of the electrolyte.
According to an embodiment of the present invention, the boron-containing lithium salt compound is selected from the group consisting of LiODFB (lithium difluorooxalato borate), liBOB (lithium bisoxalato borate), liBF 4 At least one of (lithium tetrafluoroborate).
According to an embodiment of the present invention, the boron-containing lithium salt compound is added in an amount of 0.5wt% to 1wt%, for example, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt% or 1.0wt% based on the total weight of the electrolyte.
According to an embodiment of the invention, the electrolyte lithium salt is selected from lithium hexafluorophosphate (LiPF) 6 ) Lithium difluorophosphate (LiPO) 2 F 2 ) One or more of lithium bistrifluoromethylsulfonyl imide, lithium difluorobisoxalato phosphate, lithium hexafluoroantimonate, lithium hexafluoroarsonate, lithium bis (trifluoromethylsulfonyl) imide, lithium bis (pentafluoroethylsulfonyl) imide, lithium tris (trifluoromethylsulfonyl) methyl or lithium bis (trifluoromethylsulfonyl) imide.
According to an embodiment of the invention, the electrolyte lithium salt is added in an amount of 13wt% to 20wt%, for example 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt% or 20wt% of the total weight of the electrolyte.
According to an embodiment of the invention, the organic solvent is selected from carbonates and/or carboxylates selected from one or several of the following solvents, which may be fluorinated or unsubstituted: ethylene Carbonate (EC), propylene Carbonate (PC), dimethyl carbonate, diethyl carbonate (DEC), ethylmethyl carbonate; the carboxylic acid ester is selected from one or more of the following solvents which are fluoro or unsubstituted: propyl acetate, n-butyl acetate, isobutyl acetate, n-pentyl acetate, isopentyl acetate, propyl Propionate (PP), ethyl Propionate (EP), methyl butyrate, ethyl n-butyrate.
According to an embodiment of the present invention, the functional additive further comprises at least one of fluoroethylene carbonate, 1, 3-propane sultone.
According to an embodiment of the invention, the electrolyte is used in a lithium ion battery.
According to an embodiment of the invention, the electrolyte satisfies the following relation:
1≤(A+B)/(C+D)≤5
wherein A is the content of dinitrile compound, B is the content of trinitrile compound, and C is the content of Si (CN) 3 The content of the functional group silicon nitrile compound, D is the content of the boron-containing lithium salt compound.
According to the embodiment of the invention, the content of the dinitrile compound refers to the percentage of the dinitrile compound added to the total weight of the electrolyte; the content of the tri-nitrile compound is the percentage of the addition of the tri-nitrile compound in the total weight of the electrolyte; said composition containing-Si (CN) 3 The content of the functional group-containing silacrylic compound means that-Si (CN) is contained 3 The addition amount of the functional group silicon nitrile compound accounts for the total weight of the electrolyte; the content of the boron-containing lithium salt compound refers to the percentage of the addition of the boron-containing lithium salt compound in the total weight of the electrolyte.
It was found that when (A+B)/(C+D)>5, the content of dinitriles and trinitriles is too high orwith-Si (CN) 3 The content of the functional group silicon nitrile compound and the boron-containing lithium salt compound is too low, so that the impedance of the battery is larger, and the performance of the battery is deteriorated; when (A+B)/(C+D)<1, the content of dinitriles and trinitriles is too low or-Si (CN) 3 The content of the functional group silicon nitrile compound and the boron-containing lithium salt compound is too high to solve the problem of high temperature of the battery.
According to an embodiment of the invention, (a+b)/(c+d) is for example 1,2,3, 4 or 5.
According to the embodiment of the invention, A is more than or equal to 2 and less than or equal to 3, B is more than or equal to 1 and less than or equal to 2, C is more than or equal to 0.5 and less than or equal to 2, and D is more than or equal to 0.5 and less than or equal to 1.
The invention also provides a battery, which comprises the electrolyte.
According to an embodiment of the invention, the battery is a lithium ion battery.
According to an embodiment of the present invention, the battery further includes a positive electrode sheet containing a positive electrode active material, a negative electrode sheet containing a negative electrode active material, and a separator.
According to an embodiment of the present invention, the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer coated on one or both side surfaces of the positive electrode current collector, the positive electrode active material layer including a positive electrode active material, a conductive agent, and a binder.
According to an embodiment of the present invention, the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer coated on one or both side surfaces of the negative electrode current collector, the negative electrode active material layer including a negative electrode active material, a conductive agent, and a binder.
According to an embodiment of the present invention, the positive electrode active material layer comprises the following components in percentage by mass: 80 to 99.8 weight percent of positive electrode active material, 0.1 to 10 weight percent of conductive agent and 0.1 to 10 weight percent of binder.
Preferably, the positive electrode active material layer comprises the following components in percentage by mass: 90 to 99.6 weight percent of positive electrode active material, 0.2 to 5 weight percent of conductive agent and 0.2 to 5 weight percent of binder.
According to an embodiment of the present invention, the mass percentage of each component in the anode active material layer is: 80 to 99.8 weight percent of negative electrode active material, 0.1 to 10 weight percent of conductive agent and 0.1 to 10 weight percent of binder.
Preferably, the mass percentage of each component in the anode active material layer is as follows: 90 to 99.6 weight percent of negative electrode active material, 0.2 to 5 weight percent of conductive agent and 0.2 to 5 weight percent of binder.
According to an embodiment of the present invention, the conductive agent is at least one selected from conductive carbon black, acetylene black, ketjen black, conductive graphite, conductive carbon fiber, carbon nanotube, metal powder, and carbon fiber.
According to an embodiment of the present invention, the binder is at least one selected from sodium carboxymethyl cellulose, styrene-butadiene latex, polytetrafluoroethylene, and polyethylene oxide.
According to an embodiment of the present invention, the negative electrode active material is selected from at least one of artificial graphite, natural graphite, mesophase carbon microspheres, hard carbon, soft carbon, siOx/C, or Si/C.
According to an embodiment of the present invention, the positive electrode active material is selected from one or more of transition metal lithium oxide, lithium iron phosphate, and lithium manganate; the chemical formula of the transition metal lithium oxide is Li 1+x Ni y Co z M (1-y-z) O 2 Wherein, -0.1 is less than or equal to x is less than or equal to 1; y is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 1, and y+z is more than or equal to 0 and less than or equal to 1; wherein M is one or more of Mg, zn, ga, ba, al, fe, cr, sn, V, mn, sc, ti, nb, mo, zr.
According to an embodiment of the present invention, the battery has a charge cut-off voltage of 4.5V or more.
The invention has the beneficial effects that:
the invention provides an electrolyte and a battery comprising the electrolyte, wherein the functional additive in the electrolyte comprises a dinitrile compound, a trinitrile compound and a catalyst containing-Si (CN) 3 The functional group silicon nitrile compound and the boron-containing lithium salt compound can jointly act on the surface of the positive electrode to form a composite electrolyte membrane, so that the positive electrode active material is effectively protected, and meanwhile, the composite electrolyte membrane can be preventedThe electrolyte is oxidized and decomposed, so that the stability of the positive electrode active material is improved.
Specifically, the composition contains-Si (CN) 3 The silicon (Si) in the functional group of the silicon nitrile compound can trap fluoride (F-) in the electrolyte, i.e. react with HF in the electrolyte (4hf+si=sif) 4 +2H 2 ) Reducing or even avoiding the influence of HF on the positive electrode, inhibiting the dissolution of transition metal ions, and simultaneously containing-Si (CN) 3 The cyano functional group in the functional group silicon nitrile compound is an electron-withdrawing group with a relatively high dipole moment, can be complexed with the surface of the positive electrode, and can effectively inhibit the dissolution of transition metal ions and the further oxidative decomposition of the electrolyte.
Furthermore, even if transition metal ions are present in the electrolyte system, the electrolyte contains-Si (CN) 3 The functional group of the silicon nitrile compound can react with transition metal ions preferentially, so that the transition metal ions are prevented from being reduced at the negative electrode. The boron-containing lithium salt compound can react with the O hole center on the Co-O surface in the positive electrode active material to generate Lewis acid F 2 BOCO radical, then coordinates with O on the Co-O surface, combines with each other through two free electrons to form bond, and exists on the Co-O surface stably, and the boron-containing lithium salt compound can be combined with dinitrile compound, trinitrile compound and Si (CN) 3 The functional group silicon nitrile compound acts on the surface of the positive electrode together to protect the positive electrode active material, prevent the electrolyte from being oxidized and decomposed, and improve the stability of the positive electrode active material.
Detailed Description
The present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are illustrative only and are not to be construed as limiting the scope of the invention. All techniques implemented based on the above description of the invention are intended to be included within the scope of the invention.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; the reagents, materials, etc. used in the examples described below are commercially available unless otherwise specified.
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It is understood that the lithium ion battery of the invention comprises a negative plate, electrolyte, a positive plate, a separation film and an outer package. And stacking the positive plate, the isolating film and the negative plate to obtain a battery cell, or winding the positive plate, the isolating film and the negative plate to obtain the battery cell, placing the battery cell in an outer package, and injecting electrolyte into the outer package to obtain the lithium ion battery.
Examples 1-9 lithium ion batteries of comparative examples 1-4 were prepared by the following steps:
1) Preparation of positive plate
Lithium cobalt oxide (LiCoO) as a positive electrode active material 2 ) Mixing polyvinylidene fluoride (PVDF), SP (super P) and Carbon Nano Tube (CNT) according to the mass ratio of 96:2:1.5:0.5, adding N-methyl pyrrolidone (NMP), and stirring under the action of a vacuum stirrer until the mixed system becomes anode active slurry with uniform fluidity; uniformly coating anode active slurry on two surfaces of an aluminum foil; and drying the coated aluminum foil, and then rolling and slitting to obtain the required positive plate.
2) Preparation of negative plate
Mixing negative electrode active materials of artificial graphite, silicon oxide, sodium carboxymethylcellulose (CMC-Na), styrene-butadiene rubber, conductive carbon black (SP) and single-walled carbon nanotubes (SWCNTs) according to the mass ratio of 79.5:15:2.5:1.5:1:0.5, adding deionized water, and obtaining negative electrode active slurry under the action of a vacuum stirrer; uniformly coating the anode active slurry on two surfaces of a copper foil; and (3) airing the coated copper foil at room temperature, transferring to an 80 ℃ oven for drying for 10 hours, and then carrying out cold pressing and slitting to obtain the negative plate.
3) Preparation of electrolyte
In a glove box filled with argon (H 2 O<0.1ppm，O 2 <0.1 ppm), EC/PC/DEC/PP was uniformly mixed in a mass ratio of 10/20/40/30, and then 1mol/L of sufficiently dried lithium hexafluorophosphate (LiPF) was rapidly added thereto 6 ) Adding fluoroethylene carbonate with the weight percent of 10 percent based on the total mass of the electrolyte, and adding the compound shown as A5, liODFB, succinonitrile and triglyceride with the addition amount shown in the table below; specific electrolyte formulations examples and comparative examples are as follows, and electrolytes are injected into the dried batteries, respectively.
4) Preparation of lithium ion batteries
Laminating the positive plate in the step 1), the negative plate in the step 2) and the isolating film according to the sequence of the positive plate, the isolating film and the negative plate, and then winding to obtain the battery cell; and (3) placing the battery cell in an outer packaging aluminum foil, injecting the electrolyte in the step (3) into the outer packaging, and performing the procedures of vacuum packaging, standing, formation, shaping, sorting and the like to obtain the lithium ion battery. The charge and discharge range of the battery is 3.0-4.5V.
The lithium ion batteries obtained in examples and comparative examples were subjected to a 45 ℃ high temperature cycle performance test, a 85 ℃ high temperature storage performance test, and a 130 ℃ safety performance test, respectively, and the test results are shown in table 1.
1) 45 ℃ high temperature cycle performance test
Firstly, carrying out charge-discharge circulation for 1000 weeks at 45 ℃ according to a multiplying power of 1C within a charge-discharge cut-off voltage range after the formation of the components, wherein the discharge capacity at the 1 st week is tested to be x1mAh, and the discharge capacity at the N week is tested to be y1mAh; the capacity at week N divided by the capacity at week 1 gives the cyclic capacity retention rate at week N r1=y1/x 1.
2) 85 ℃ high-temperature storage performance test
Firstly, standing the battery with the chemical components for 10min, then standing for 10min at 0.2C and 3V, then fully charging at 0.5C, stopping at 0.05C, and standing for 10min. And testing the voltage, the internal resistance and the thickness of the full-charge state at the temperature of 25+/-5 ℃, placing the full-charge state in an oven at the temperature of 85 ℃ for 8 hours, taking out the voltage, the internal resistance and the thickness of the thermal state battery, and performing capacity retention and recovery tests.
3) 130 ℃ safety performance test
Firstly, standing the battery with the chemical components for 10min, then standing for 10min at 0.2C and 3V, then fully charging at 0.5C, stopping at 0.05C, and standing for 10min. Testing voltage, internal resistance and thickness of the battery in a full-charge state at 25+/-5 ℃, placing the battery in a 130 ℃ thermal shock test box, raising the temperature to 135 ℃ at a speed of 6+/-2 ℃/min, and keeping the monitoring voltage and the body temperature rise for 30 min. If the battery does not fire, it is denoted as "NO", and if the battery fires, it is denoted as "YES"; if the battery does not explode, it is denoted as "NO", and if the battery explodes, it is denoted as "YES".
Table 1 composition of electrolyte additives and results of performance test in batteries of examples and comparative examples
From the comparison of examples and comparative examples in Table 1, containing-Si (CN) 3 The addition of the functional group of the silicon nitrile compound was more remarkable in improvement of 45℃cycle and 85℃high-temperature storage property, and as is clear from comparison of comparative examples 2 to 3 with example 7, the kind of nitrile compound had an effect on safety performance.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. An electrolyte, characterized in that the electrolyte comprises an organic solvent, an electrolyte lithium salt and a functional additive, wherein the functional additive comprises a dinitrile compound, a trinitrile compound and a catalyst containing-Si (CN) 3 Functional group silicon nitrile compound and boron-containing lithium salt compound.
2. The electrolyte according to claim 1, characterized in thatThe above-mentioned material contains-Si (CN) 3 The functional group silicon nitrile compound is selected from at least one of compounds shown in a formula 1:
in the formula (1), R 1 Selected from hydrogen, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl; in the case of substitution, the substituents are halogen, cyano, alkyl.
3. The electrolyte according to claim 2, wherein in formula (1), R 1 Selected from hydrogen, cyano, substituted or unsubstituted C 1-6 Alkyl, substituted or unsubstituted C 2-6 Alkenyl, substituted or unsubstituted C 6-12 An aryl group; in the case of substitution, the substituents are halogen, cyano, C 1-6 An alkyl group.
4. The electrolyte according to claim 1, wherein the electrolyte contains-Si (CN) 3 The addition amount of the functional group silicon nitrile compound is 0.5-2 wt% of the total weight of the electrolyte.
5. The electrolyte according to claim 1, wherein the dinitrile compound is at least one selected from the group consisting of succinonitrile, adiponitrile, glutaronitrile, terephthalonitrile, fumaric dinitrile, cyclohexane-1, 4-dinitrile, 1, 2-bis (cyanoethoxy) ethane, suberonitrile, 4-fluorophthalonitrile, 2-cyanoethyl ether, 1-ethyl-3-methylimidazole dicyan methylene salt, 3' -iminodiproponitrile, azobisisobutyronitrile;
and/or the addition amount of the dinitrile compound is 2-3.0 wt% of the total weight of the electrolyte.
6. The electrolyte according to claim 1, wherein the trinitrile compound is at least one selected from the group consisting of 1,2, 3-tris (2-cyanooxy) propane, 1,3, 6-hexanetrinitrile, 2-amino-1, 3-tricyano-1-propene, tris (2-cyanoethyl) borate, tris (2-cyanoethyl) phosphine;
and/or the addition amount of the tri-nitrile compound is 1 to 2.0 weight percent of the total weight of the electrolyte.
7. The electrolyte according to claim 1, wherein the boron-containing lithium salt compound is selected from the group consisting of LiODFB (lithium difluorooxalato borate), liBOB (lithium bisoxalato borate), liBF 4 At least one of (lithium tetrafluoroborate);
and/or the adding amount of the boron-containing lithium salt compound is 0.5-1 wt% of the total weight of the electrolyte.
8. The electrolyte of claim 1 wherein the functional additive further comprises at least one of fluoroethylene carbonate, 1, 3-propane sultone.
9. The electrolyte of claim 1, wherein the electrolyte satisfies the relationship:
1≤(A+B)/(C+D)≤5
wherein A is the content of dinitrile compound, B is the content of trinitrile compound, and C is the content of Si (CN) 3 The content of the functional group silicon nitrile compound, D is the content of the boron-containing lithium salt compound.
10. A battery, characterized in that it comprises the electrolyte according to any one of claims 1-9.
CN202211098340.3A 2022-09-08 2022-09-08 Electrolyte and battery comprising same Pending CN117673467A (en)

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