CN115441057A - Electrolyte and battery comprising same - Google Patents
Electrolyte and battery comprising same Download PDFInfo
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- CN115441057A CN115441057A CN202211229053.1A CN202211229053A CN115441057A CN 115441057 A CN115441057 A CN 115441057A CN 202211229053 A CN202211229053 A CN 202211229053A CN 115441057 A CN115441057 A CN 115441057A
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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
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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
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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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
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Abstract
The invention provides an electrolyte and a battery comprising the same. The first additive in the functional additives in the electrolyte is a sulfonyl fluoride compound containing unsaturated bonds, wherein the unsaturated bonds can generate polymerization reaction on the surface of the positive electrode to form a protective film, so that the oxidation resistance of the solid electrolyte film on the positive electrode side can be improved; substitution of fluorine atoms can also further improve the oxidation resistance of the positive electrode-side solid electrolyte membrane; the use of the first additive can improve the high-temperature cycle performance, the high-temperature storage performance, and the safety performance of the battery.
Description
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
A lithium ion battery is a type of rechargeable battery that mainly relies on lithium ions moving between a positive electrode and a negative electrode to operate. During charging and discharging, li + Intercalation and deintercalation to and from two electrodes: on charging, li + The lithium ion battery is extracted from the positive electrode and is inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true for discharge. The lithium ion battery has the advantages of high specific energy, no memory effect, long cycle life, small self-discharge and the like, so the lithium ion battery is wideThe method is applied to the fields of digital codes, energy storage, electric automobiles and the like. Along with the improvement of living standard and the trend of more beautiful life of people, the upgrading of battery application scenes not only puts forward the requirements on the energy density of the battery, but also puts forward the requirements on different use temperature ranges.
The energy density of the battery can be improved by improving the limiting voltage of the anode material, but along with the continuous improvement of the limiting voltage of the anode material, the gram capacity of the electrode material is gradually increased, the high-temperature performance of the battery is seriously deteriorated, the long cycle life cannot be ensured, especially under the high voltage (> 4.5V), the structure of the anode material can be damaged in the long-term cycle charging and discharging process, meanwhile, the release of active oxygen further accelerates the oxidative decomposition of electrolyte, the protective film on the surface of the cathode can be continuously damaged, and finally, the capacity of the battery is seriously attenuated.
Meanwhile, news about the fire and explosion of lithium ion battery electronic equipment is also frequently reported in society, and the safety performance of the lithium ion battery can be ensured while the energy density and the charging speed are improved, and the news still needs to be overcome continuously.
Disclosure of Invention
The invention aims to solve the problems that the volume of a positive electrode material in a lithium ion battery is expanded and active oxygen is released to continuously oxidize an electrolyte under high voltage, and provides the electrolyte and the battery comprising the electrolyte.
The invention aims to realize the following technical scheme:
the electrolyte comprises an organic solvent, a lithium salt and a functional additive, wherein the functional additive comprises a first additive, and the first additive is a sulfonyl fluoride compound containing an unsaturated bond.
According to an embodiment of the present invention, the unsaturated bond-containing sulfonyl fluoride-based compound includes an unsaturated double bond and a sulfonyl fluoride group (-SO) 2 -F)。
According to an embodiment of the invention, the unsaturated-containing compound containsThe sulfonyl fluoride compound with the bond is a sulfonyl fluoride compound containing a fluorine-substituted unsaturated bond, and the sulfonyl fluoride compound containing the fluorine-substituted unsaturated bond comprises a fluorine-substituted unsaturated double bond (CF) 2 = CF-) and a sulfonyl fluoride group (-SO) 2 -F)。
According to an embodiment of the invention, the first additive is selected from at least one of the compounds of formula I:
in the formula I, R 4 、R 5 、R 6 Identical or different, independently of one another, from hydrogen, halogen, substituted or unsubstituted alkyl; if substituted, the substituent is halogen or alkyl;
R 2 、R 3 identical or different, independently of one another, from O or S;
R 2a 、R 2b 、R 2c 、R 2d 、R 3a 、R 3b 、R 3c 、R 3d identical or different, independently of one another, from the group consisting of hydrogen, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl; if substituted, the substituent is halogen or alkyl.
According to an embodiment of the invention, R 4 、R 5 、R 6 Identical or different, independently of one another, from hydrogen, halogen, substituted or unsubstituted C 1-12 An alkyl group; if substituted, the substituents are halogen, C 1-12 An alkyl group.
According to an embodiment of the invention, R 4 、R 5 、R 6 Identical or different, independently of one another, from hydrogen, halogen, substituted or unsubstituted C 1-6 An alkyl group; if substituted, the substituents are halogen, C 1-6 An alkyl group.
According to an embodiment of the invention, R 4 、R 5 、R 6 Identical or different, independently of one another, from hydrogen, fluorine, substituted or unsubstituted C 1-3 An alkyl group; if it is substituted, takeThe substituent is fluorine or C 1-3 An alkyl group.
According to an embodiment of the invention, R 4 、R 5 、R 6 And is selected from fluorine.
According to an embodiment of the invention, R 2a 、R 2b 、R 2c 、R 2d 、R 3a 、R 3b 、R 3c 、R 3d Are identical or different and are independently selected from hydrogen, halogen, substituted or unsubstituted C 1-12 Alkyl, substituted or unsubstituted 3-12 membered cycloalkyl, substituted or unsubstituted C 6-12 An aryl group; if substituted, the substituents are halogen, C 1-12 An alkyl group.
According to an embodiment of the invention, R 2a 、R 2b 、R 2c 、R 2d 、R 3a 、R 3b 、R 3c 、R 3d Identical or different, independently of one another, from hydrogen, halogen, substituted or unsubstituted C 1-6 Alkyl, substituted or unsubstituted 3-8 membered cycloalkyl, substituted or unsubstituted C 6-10 An aryl group; if substituted, the substituents are halogen, C 1-6 An alkyl group.
According to an embodiment of the invention, R 2a 、R 2b 、R 2c 、R 2d 、R 3a 、R 3b 、R 3c 、R 3d Identical or different, independently of one another, from hydrogen, halogen, substituted or unsubstituted C 1-3 Alkyl, substituted or unsubstituted 3-6 membered cycloalkyl, substituted or unsubstituted C 6-8 An aryl group; if substituted, the substituents are halogen, C 1-3 An alkyl group.
According to embodiments of the present invention, the first additive may be prepared by methods known in the art or may be commercially available.
According to an embodiment of the present invention, the first additive is at least one selected from compounds represented by formula (1) to formula (9):
according to an embodiment of the present invention, the electrolyte further includes a second additive selected from at least one of polynitrile compounds.
According to an embodiment of the present invention, the polynitrile compound is at least one selected from the group consisting of a dinitrile compound represented by formula II-1, a trinitrile compound represented by formula II-2, and a tetranitrile compound represented by formula II-3:
wherein R is 21 Is a group having 1 to 10 carbon atoms and having at least 2 substitution positions; r 22 Is a group having 1 to 10 carbon atoms and having at least 3 substitution positions; r 23 Is a group having 1 to 10 carbon atoms and having at least 4 substitution positions.
According to an embodiment of the invention, the group having 1 to 10 carbon atoms is selected from substituted or unsubstituted C 1 - 10 Alkyl, substituted or unsubstituted C 1-10 Alkoxy, substituted or unsubstituted C 2-10 Alkenyl, substituted or unsubstituted C 1-10 alkyl-O-C 1-10 Alkyl, substituted or unsubstituted C 1-10 alkyl-C (O) -C 1-10 Alkyl, substituted or unsubstituted C 4-10 Heteroaryl, substituted or unsubstituted C 4-10 Heterocyclic radical, substituted or unsubstituted C 6-10 Aryl, the substituent being halogen, substituted or unsubstituted C 1-10 An alkyl group.
According to an embodiment of the present invention, the dinitrile compound represented by formula II-1 is selected from at least one of the following compounds: succinonitrile, glutaronitrile, adiponitrile, sebaconitrile, nonanedionitrile, dicyanobenzene, terephthalonitrile, pyridine-3,4-dinitrile, 2,5-dicyanopyridine, 2,2,3,3-tetrafluorosuccinonitrile, tetrafluoroterephthalonitrile, 4-tetrahydrothiopyran methylenemalononitrile, 3,3' - [1,2-ethanediylbis (oxy) ] dipropionitrile, fumaronitrile, ethyleneglycol dipropionitrile ether and 1,4,5,6-tetrahydro-5,6-dioxo-2,3-pyrazinecarbonitrile.
According to an embodiment of the present invention, the trinitrile compound represented by the formula II-2 is selected from at least one of the following compounds: 1,3,6-Hexanetricarbonitrile, 1,3,5-Cyclohexanetricarbonitrile, 1,3,5-benzenetricarbonitrile, 1,2,3-propanetricyanide, glycerol trinitrile.
According to an embodiment of the present invention, the tetracyanonitrile compound represented by the formula II-3 is at least one compound selected from the group consisting of: 1,1,3,3-propanetetracyclonitrile, 1,2,2,3-tetracyanopropane, 1,2,4,5-tetracyanobenzene, 2,3,5,6-pyrazine tetracyclonitrile, 7,7,8,8-tetracyanoterephthalenediquinodimethane, tetracyanoethylene, 1,1,2,2, -tetrakis (ethoxycyano) ethane, 3-methyl-3-propyl-cyclopropane-1,1,2,2-tetracyclonitrile.
According to an embodiment of the present invention, the electrolyte further includes a third additive selected from at least one of fluorosulfonic acid imide salts.
According to an embodiment of the invention, the third additive is selected from at least one of the compounds of formula III:
in the formula III, R 1 Selected from one of Li, na, K, rb and Cs.
According to embodiments of the present invention, the third additive may be prepared by methods known in the art or may be commercially available.
According to an embodiment of the invention, the third additive is selected from at least one of the compounds represented by formulae III-1 to III-5:
according to an embodiment of the present invention, the first additive is added in an amount of 0.1wt% to 5.0wt%, for example, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 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%, 2wt%, 2.2wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.8wt%, 3wt%, 3.3wt%, 3.5wt%, 3.8wt%, 4wt%, 4.2wt%, 4.5wt%, 4.8wt%, or 5wt% based on the total weight of the electrolyte.
According to an embodiment of the invention, the second additive is added in an amount of 1wt% to 5.0wt%, such as 1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2wt%, 2.2wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.8wt%, 3wt%, 3.3wt%, 3.5wt%, 3.8wt%, 4wt%, 4.2wt%, 4.5wt%, 4.8wt%, or 5wt% based on the total weight of the electrolyte.
According to an embodiment of the present invention, the third additive is added in an amount of 1wt% to 5.0wt%, for example, 1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2wt%, 2.2wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.8wt%, 3wt%, 3.3wt%, 3.5wt%, 3.8wt%, 4wt%, 4.2wt%, 4.5wt%, 4.8wt%, or 5wt% based on the total weight of the electrolyte.
According to an embodiment of the present invention, the electrolyte further comprises a fourth additive selected from at least one of fluoroethylene carbonate and 1,3-propane sultone.
According to an embodiment of the present invention, the fourth additive is added in an amount of 10wt% to 15wt%, for example, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or 15wt% based on the total weight of the electrolyte.
According to an embodiment of the invention, the lithium salt is selected from lithium hexafluorophosphate (LiPF) 6 ) Lithium difluorophosphate (LiPO) 2 F 2 ) Lithium difluorooxalato borate (LiDFOB), bis (trifluoromethyl)One or more of lithium arylsulfonylimide, lithium difluorobis (oxalato) phosphate, lithium tetrafluoroborate, lithium bis (oxalato) borate, lithium hexafluoroantimonate, lithium hexafluoroarsenate, lithium bis (trifluoromethylsulfonyl) imide, lithium bis (pentafluoroethylsulfonyl) imide, lithium tris (trifluoromethylsulfonyl) methide or lithium bis (trifluoromethylsulfonyl) imide.
According to an embodiment of the present invention, the organic solvent is selected from carbonates and/or carboxylic esters, the carbonates being selected from one or several of the following fluorinated or unsubstituted solvents: ethylene Carbonate (EC), propylene Carbonate (PC), dimethyl carbonate, diethyl carbonate (DEC), ethyl methyl carbonate; the carboxylic ester is selected from one or more of the following fluorinated or unsubstituted solvents: propyl acetate, n-butyl acetate, isobutyl acetate, n-pentyl acetate, isoamyl acetate, propyl Propionate (PP), ethyl Propionate (EP), methyl butyrate, ethyl n-butyrate.
According to an embodiment of the invention, the electrolyte is used in a lithium ion battery.
The invention also provides a battery, which comprises the electrolyte.
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 surfaces of the positive electrode current collector, and the positive electrode active material layer includes 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 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 the embodiment of the invention, the mass percentage of each component in the positive electrode active material layer is as follows: 80-99.8 wt% of positive active material, 0.1-10 wt% of conductive agent and 0.1-10 wt% of binder.
Preferably, the positive electrode active material layer comprises the following components in percentage by mass: 90-99.6 wt% of positive active material, 0.2-5 wt% of conductive agent and 0.2-5 wt% of binder.
According to the embodiment of the invention, the anode active material layer comprises the following components in percentage by mass: 80-99.8 wt% of negative active material, 0.1-10 wt% of conductive agent and 0.1-10 wt% of binder.
Preferably, the negative electrode active material layer comprises the following components in percentage by mass: 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 negative active material is selected from at least one of artificial graphite, natural graphite, mesocarbon microbeads, hard carbon, soft carbon, and a silicon-based negative active material.
According to the embodiment of the invention, the positive active material is selected from one or more of transition metal lithium oxide, lithium iron phosphate, lithium manganate and lithium manganese iron phosphate; the chemical formula of the transition metal lithium oxide is Li 1+x Ni y Co z M (1-y-z) O 2 Wherein x is more than or equal to-0.1 and less than or equal to 1; y is more than or equal to 0 and less than or equal to 1,0 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 and Zr.
The invention has the beneficial effects that:
the invention provides an electrolyte and a battery comprising the same. The first additive in the electrolyte is a sulfonyl fluoride compound containing unsaturated bonds, wherein the unsaturated bonds can generate polymerization reaction on the surface of the positive electrode to form a protective film, so that the oxidation resistance of the solid electrolyte film on the positive electrode side can be improved; the F-C-O structure or the F-C-S structure in the sulfonyl fluoride compound containing the unsaturated bond can improve the oxidation resistance of the electrolyte, and the substitution of the fluorine atom can further improve the oxidation resistance of the solid electrolyte membrane on the positive electrode side; the sulfonyl fluoride compound containing the unsaturated bond can form lithium alkyl sulfonate on the negative electrode side in the formation stage, so that the ionic conductivity of the SEI film is increased; the temperature of the battery under the limit working condition can reach more than 130 ℃, namely the polymerization reaction temperature of the sulfonyl fluoride compound containing the unsaturated bond is reached, the sulfonyl fluoride compound monomer containing the unsaturated bond can generate polymerization reaction to form a polymer, and simultaneously the generated polymer forms a blocking layer on the surface of an electrode, so that the internal resistance of the battery is rapidly increased, the further reaction of electrolyte is reduced, and the gas generation and heat of the battery are obviously reduced and reduced. Therefore, the use of the first additive can improve the high-temperature cycle performance, the high-temperature storage performance, and the safety performance of the battery.
The polynitrile compound as the second additive is introduced on the basis of the first additive, wherein the cyano group can fully complex the transition metal ions in the positive active material, and forms a protective layer on the positive side together with the first additive, so that the transition metal ions in the positive active material are prevented from dissolving out, and the high-temperature cycle performance and the high-temperature storage performance of the battery are improved.
On the basis of the first additive, fluorosulfonic acid imide salt serving as a third additive is introduced, and can act on the positive electrode to form a protective layer, so that the high-temperature cycle performance and the high-temperature storage performance of the battery are improved.
The polynitrile compound as a second additive and the fluorosulfonic acid imide salt as a third additive are introduced on the basis of the first additive, and are coated on the surface of the positive electrode interface under the combined action of the first additive, the second additive and the third additive to form a synergistic effect, so that electrolyte is prevented from entering the positive electrode active material layer to corrode the positive electrode active material, and the battery has excellent high-temperature cycle performance and high-temperature storage performance.
The fourth additive can participate in the generation of an SEI film at the initial formation stage, plays a role in protecting a negative electrode, and can also continuously repair a damaged SEI film at the later cycle stage, so that the electrochemical performance of the battery is improved.
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 only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.
In the description of the present invention, it should be noted that the terms "first", "second", "third", "fourth", etc. are used for descriptive purposes only and do not indicate or imply relative importance.
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It is understood that the lithium ion battery of the present invention includes a negative electrode tab, an electrolyte, a positive electrode tab, a separator, and an outer package. The lithium ion battery can be obtained by stacking the positive plate, the isolating membrane and the negative plate to obtain the battery cell or stacking the positive plate, the isolating membrane and the negative plate, then winding to obtain the battery cell, placing the battery cell in an outer package, and injecting electrolyte into the outer package.
Examples 1 to 18 and comparative examples 1 to 7
The lithium ion batteries of examples 1 to 18 and comparative examples 1 to 7 were prepared by the following steps:
1) Preparation of positive plate
The positive electrode active material lithium cobaltate (LiCoO) 2 ) Mixing polyvinylidene fluoride (PVDF), SP (super P) and Carbon Nano Tubes (CNT) according to a mass ratio of 96; uniformly coating the positive active slurryOn both surfaces of the 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 artificial graphite serving as a negative electrode active material, sodium carboxymethylcellulose (CMC-Na), styrene butadiene rubber, conductive carbon black (SP) and single-walled carbon nanotubes (SWCNTs) according to a mass ratio of 94.5; uniformly coating the negative active slurry on two surfaces of a copper foil; and airing the coated copper foil at room temperature, transferring the copper foil to an oven at 80 ℃ for drying for 10 hours, and then carrying out cold pressing and slitting to obtain the negative plate.
3) Preparation of the 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 10/10/20/60, and then 13wt% of fully dried lithium hexafluorophosphate (LiPF) based on the total mass of the electrolyte was rapidly added thereto 6 ) After dissolving, 8wt% of fluoroethylene carbonate and 4wt% of 1,3-propane sultone based on the total mass of the electrolyte are added, and a first additive, a second additive (adiponitrile) and a third additive (a compound shown in a formula III-1) are added according to the additives shown in tables 1 and 3 and are uniformly mixed to prepare the electrolyte.
4) Preparation of lithium ion battery
Stacking the positive plate in the step 1), the negative plate in the step 2) and the isolation film in the order of the positive plate, the isolation film and the negative plate, and then winding to obtain a battery cell; placing the battery cell in an aluminum foil package, injecting the electrolyte in the step 3) into the package, and performing vacuum packaging, standing, formation, shaping, sorting and other processes to obtain the lithium ion battery. The battery of the invention has a charge-discharge range of 3.0-4.5V.
TABLE 1 compositions of electrolyte additives in lithium ion batteries of examples and comparative examples
| First additive and content | Second additive content | Third additive content | |
| Example 1 | Formula (1)/1 wt% | / | / |
| Example 2 | Formula (2)/1 wt% | / | / |
| Example 3 | Formula (3)/1 wt% | / | / |
| Example 4 | Formula (4)/1 wt% | / | / |
| Example 5 | Formula (5)/1 wt% | / | / |
| Example 6 | Formula (6)/1 wt% | / | / |
| Example 7 | Formula (7)/1 wt% | / | / |
| Example 8 | Formula (8)/1 wt% | / | / |
| Example 9 | Formula (9)/1 wt% | / | / |
| Comparative example 1 | / | / | / |
| Comparative example 2 | / | 3wt％ | / |
| Comparative example 3 | / | 4wt％ | / |
| Comparative example 4 | / | 5wt％ | / |
| Comparative example 5 | / | / | 1wt％ |
| Comparative example 6 | / | / | 2wt％ |
| Comparative example 7 | / | / | 3wt％ |
The lithium ion batteries obtained in the examples and comparative examples were respectively subjected to the following performance tests:
1) 45 ℃ cycle performance test
Carrying out charge-discharge circulation on the divided battery cell within a charge-discharge cut-off voltage range for 1000 weeks at 45 ℃ according to the multiplying power of 1C, wherein the discharge capacity in the 1 st week is measured to be x1mAh, and the discharge capacity in the Nth circle is measured to be y1mAh; the capacity at week N was divided by the capacity at week 1 to obtain the cycle capacity retention rate at week N, R1= y1/x1, and the test results are shown in tables 2 and 4.
2) High temperature storage test at 85 deg.C
And (3) charging the partial-volume battery cell to 4.5V at the normal temperature by using 0.5C current, placing the fully-charged battery in an environment of 85 ℃ for 6 hours, thermally measuring the thickness expansion rate, discharging to 3.0V at the current of 0.5C after the room temperature is recovered, and recording the discharge capacity, wherein the test results are shown in tables 2 and 4.
3) Safety performance testing
Charging the battery cell 0.5C to the upper limit and cutting to the voltage, and keeping the voltage constant to 0.05C; the fully charged sample was placed in a thermal shock test chamber at ambient temperature 25 c 5c, then raised to 140 c 2 c at a rate of 15 c 2 c/min and held at this temperature for 42min before the test was completed and the cell was observed for ignition and the test results are shown in tables 2 and 4.
Table 2 results of performance test of lithium ion batteries of examples and comparative examples
As can be seen from the test results of examples 1 to 9 and comparative example 1 in table 2, the first additive can significantly improve the high-temperature cycle performance, the high-temperature storage performance, and the safety performance of the battery, and the improvement effect of the first additive containing the F substituent is more significant, but the excessive substituent may also be somewhat deteriorated depending on the number of substituents. And the second additive and the third additive can improve the high-temperature cycle performance and the high-temperature storage performance of the battery, wherein the optimal dosage of the second additive is 4wt%, and the optimal dosage of the third additive is 2wt%; wherein, the safety performance is obviously improved when the dosage of the third additive is more than or equal to 2wt percent.
Table 3 compositions of electrolyte additives in lithium ion batteries of examples and comparative examples
| First additive and content | Content of the second additive | Third additive content | |
| Example 10 | Formula (7)/0.5 wt% | 4wt％ | / |
| Example 11 | Formula (7)/0.5 wt% | / | 2wt％ |
| Example 12 | Formula (7)/1 wt% | 4wt％ | / |
| Example 13 | Formula (7)/1 wt% | / | 2wt％ |
| Example 14 | Formula (7)/3 wt% | 4wt％ | / |
| Example 15 | Formula (7)/3 wt% | / | 2wt％ |
| Example 16 | Formula (7)/0.5 wt% | 4wt％ | 2wt％ |
| Example 17 | Formula (7)/1 wt% | 4wt％ | 2wt％ |
| Example 18 | Formula (7)/3 wt% | 4wt％ | 2wt％ |
Table 4 results of performance test of lithium ion batteries of examples and comparative examples
As can be seen from the test results of examples 10 to 18 of table 4, when the first additive, the second additive and the third additive act together, the high-temperature cycle performance, the high-temperature storage performance and the safety performance of the battery can be significantly improved, which indicates that there is a synergistic effect among the first additive, the second additive and the third additive.
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, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The electrolyte is characterized by comprising an organic solvent, a lithium salt and a functional additive, wherein the functional additive comprises a first additive, and the first additive is a sulfonyl fluoride compound containing an unsaturated bond.
2. The electrolyte according to claim 1, wherein the unsaturated bond-containing sulfonyl fluoride compound is a fluorine-substituted unsaturated bond-containing sulfonyl fluoride compound, and the fluorine-substituted unsaturated bond-containing sulfonyl fluoride compound includes a fluorine-substituted unsaturated double bond (CF) 2 = CF-) and sulfonyl fluoride (-SO) 2 -F)。
3. The electrolyte of claim 1 or 2, wherein the first additive is selected from at least one of the compounds of formula I:
in the formula I, R 4 、R 5 、R 6 Identical or different, independently of one another, from hydrogen, halogen, substituted or unsubstituted alkyl; if substituted, the substituent is halogen or alkyl;
R 2 、R 3 identical or different, independently of one another, from O or S;
R 2a 、R 2b 、R 2c 、R 2d 、R 3a 、R 3b 、R 3c 、R 3d identical or different, independently of one another, from the group consisting of hydrogen, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl; if substituted, the substituent is halogen or alkyl.
4. The electrolyte of claim 1, further comprising a second additive selected from at least one of polynitrile compounds.
5. The electrolyte according to claim 4, wherein the polynitrile compound is at least one selected from the group consisting of a dinitrile compound represented by formula II-1, a trinitrile compound represented by formula II-2, and a tetranitrile compound represented by formula II-3:
wherein R is 21 Is a group having 1 to 10 carbon atoms and having at least 2 substitution positions; r 22 Is a group having 1 to 10 carbon atoms and having at least 3 substitution positions; r 23 Is a group having 1 to 10 carbon atoms and having at least 4 substitution positions.
6. The electrolyte of claim 1, further comprising a third additive selected from at least one of fluorosulfonate iminates.
7. The electrolyte of claim 1 or 2, wherein the first additive is added in an amount of 0.1 to 5.0wt% based on the total weight of the electrolyte.
8. The electrolyte of claim 4 or 5, wherein the second additive is added in an amount of 1wt% to 5.0wt% based on the total weight of the electrolyte.
9. The electrolyte of claim 6, wherein the third additive is added in an amount of 1wt% to 5.0wt% based on the total weight of the electrolyte.
10. A battery comprising the electrolyte of any one of claims 1-9.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211229053.1A CN115441057A (en) | 2022-10-09 | 2022-10-09 | Electrolyte and battery comprising same |
| PCT/CN2023/122498 WO2024078357A1 (en) | 2022-10-09 | 2023-09-28 | Electrolyte solution and battery comprising same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202211229053.1A CN115441057A (en) | 2022-10-09 | 2022-10-09 | Electrolyte and battery comprising same |
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| CN115441057A true CN115441057A (en) | 2022-12-06 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202211229053.1A Pending CN115441057A (en) | 2022-10-09 | 2022-10-09 | Electrolyte and battery comprising same |
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| Country | Link |
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| CN (1) | CN115441057A (en) |
| WO (1) | WO2024078357A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024078357A1 (en) * | 2022-10-09 | 2024-04-18 | 珠海冠宇电池股份有限公司 | Electrolyte solution and battery comprising same |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9153836B2 (en) * | 2007-08-23 | 2015-10-06 | Sony Corporation | Electrolytic solutions and battery |
| CN104823318A (en) * | 2012-12-06 | 2015-08-05 | 宇部兴产株式会社 | Nonaqueous electrolyte solution and electrical storage device employing same |
| JP6285332B2 (en) * | 2014-09-24 | 2018-02-28 | 三井化学株式会社 | Nonaqueous electrolyte for battery and lithium secondary battery |
| KR102479725B1 (en) * | 2017-08-03 | 2022-12-21 | 삼성에스디아이 주식회사 | Electrolytic solution for lithium battery and lithium battery including the same |
| KR102463794B1 (en) * | 2017-08-24 | 2022-11-04 | 미쓰이 가가쿠 가부시키가이샤 | Non-aqueous electrolyte for batteries and lithium secondary batteries |
| DE102018217758A1 (en) * | 2018-10-17 | 2020-04-23 | Robert Bosch Gmbh | Polymer electrolyte composition comprising fluorine-containing additive and its use |
| CN110931872B (en) * | 2019-12-11 | 2022-07-08 | 多氟多新能源科技有限公司 | Lithium ion battery electrolyte additive and lithium ion battery electrolyte |
| CN111370766A (en) * | 2020-03-24 | 2020-07-03 | 青岛滨海学院 | Electrolyte containing-S-F group compound and electrochemical device thereof |
| CN115312860A (en) * | 2022-08-12 | 2022-11-08 | 珠海冠宇电池股份有限公司 | Electrolyte and battery comprising same |
| CN115441057A (en) * | 2022-10-09 | 2022-12-06 | 珠海冠宇电池股份有限公司 | Electrolyte and battery comprising same |
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2022
- 2022-10-09 CN CN202211229053.1A patent/CN115441057A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2024078357A1 (en) * | 2022-10-09 | 2024-04-18 | 珠海冠宇电池股份有限公司 | Electrolyte solution and battery comprising same |
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