CN116514681A - Polynitrile compound, nonaqueous electrolyte and lithium ion battery - Google Patents

Polynitrile compound, nonaqueous electrolyte and lithium ion battery Download PDF

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CN116514681A
CN116514681A CN202310487988.8A CN202310487988A CN116514681A CN 116514681 A CN116514681 A CN 116514681A CN 202310487988 A CN202310487988 A CN 202310487988A CN 116514681 A CN116514681 A CN 116514681A
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lithium
halogen
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毛冲
欧霜辉
王霹霹
曾艺安
王晓强
黄秋洁
戴晓兵
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Zhuhai Smoothway Electronic Materials Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C255/00—Carboxylic acid nitriles
    • C07C255/01—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms
    • C07C255/10—Carboxylic acid nitriles having cyano groups bound to acyclic carbon atoms containing cyano groups and halogen atoms, or nitro or nitroso groups, bound to the same acyclic carbon skeleton
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C305/00—Esters of sulfuric acids
    • C07C305/26—Halogenosulfates, i.e. monoesters of halogenosulfuric acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C309/00—Sulfonic acids; Halides, esters, or anhydrides thereof
    • C07C309/78—Halides of sulfonic acids
    • C07C309/79—Halides of sulfonic acids having halosulfonyl groups bound to acyclic carbon atoms
    • C07C309/84—Halides of sulfonic acids having halosulfonyl groups bound to acyclic carbon atoms of a carbon skeleton substituted by carboxyl groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic Table
    • C07F9/02—Phosphorus compounds
    • C07F9/06—Phosphorus compounds without P—C bonds
    • C07F9/08—Esters of oxyacids of phosphorus
    • C07F9/09—Esters of phosphoric acids
    • C07F9/14—Esters of phosphoric acids containing P(=O)-halide groups
    • 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
    • H01M10/05—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
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • 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
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • H01M2300/004—Three solvents
    • 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)
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  • Molecular Biology (AREA)
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  • Life Sciences & Earth Sciences (AREA)
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  • Secondary Cells (AREA)

Abstract

The invention provides a polynitrile compound, a non-aqueous electrolyte and a lithium ion battery thereof. The structural formula of the polynitrile compound is shown as a structural formula I or a structural formula II. Wherein R is 1 ～R 2 Each independently selected from the group consisting of halogen, halogen-substituted C1-C6 hydrocarbyl, halogen-substituted sulfonate group-containing group, halogen-substituted sulfone group-containing group, and halogen-substituted phosphonate group-containing group. The polynitrile compound of the invention is used as an electrolyte and is used at the interface of materialsA stable interfacial film having good conductive lithium ion channels, which does not collapse during cycling, and cycle and low temperature performance are improved, can be formed. In addition, at least a side chain functional group structure containing halogen is introduced, so that a thinner inorganic SEI film can be formed, SEI film sites are occupied, the problem of impedance increase caused by nitrile over-polymerization can be relieved, meanwhile, the SEI film is enriched and stabilized, transition metals in the anode material can be complexed, and therefore, the low-temperature and high-temperature storage performance can be improved.

Description

Polynitrile compound, nonaqueous electrolyte and lithium ion battery
Technical Field
The invention relates to the technical field of batteries, in particular to a polynitrile compound, a non-aqueous electrolyte of the polynitrile compound and a lithium ion battery.
Background
With the continuous increase of the capacity requirements of secondary batteries, such as pure electric vehicles, hybrid electric vehicles, portable energy storage devices, and the like, it is expected to develop secondary batteries with higher energy density and power density to realize energy storage and long-term endurance.
In addition to improvements in existing materials and manufacturing processes of batteries, high-voltage cathode materials are one of the more popular research directions that achieve high energy density of batteries by increasing the depth of charge of the cathode active material. The phase change of O3- & gtH 1-3- & gtO 1 easily occurs under high voltage and high temperature of the lithium cobaltate material, and is mainly shown as follows: 1. the phase transition kinetics becomes worse, resulting in an increase in internal resistance at high potential; 2. the structure is changed greatly, and the O3 structure disappears; 3. cell parameters expand and contract severely; 4. the slipping phase transition is not fully reversible resulting in capacity voltage decay. The macroscopic appearance of the dramatic change in cell parameters causes the volume of the material particles to expand and contract, while the change in particles causes the electrode material to change, resulting in cell attenuation. In addition, the conventional carbonate electrolyte can be oxidized and decomposed on the surface of the positive electrode of the battery under the high voltage of 4.5V, particularly under the high temperature condition, the oxidation and decomposition of the electrolyte can be accelerated, and meanwhile, the deterioration reaction of the positive electrode material is promoted.
Therefore, it is necessary to develop an electrolyte capable of withstanding a high voltage of 4.5V and further achieving excellent performance of lithium ion batteries.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a polynitrile compound which can reduce the surface activity of a positive electrode material to suppress oxidative decomposition of an electrolyte, thereby improving the high-temperature storage and cycle performance of a high-voltage (4.5V) lithium cobalt oxide system lithium ion battery, and a nonaqueous electrolyte and a lithium ion battery thereof.
To achieve the above object, the present invention provides a polynitrile compound of the formula I or II, wherein R 1 ～R 2 Each independently selected from the group consisting of halogen, halogen-substituted C1-C6 hydrocarbyl, halogen-substituted sulfonate group-containing group, halogen-substituted sulfone group-containing group, and halogen-substituted phosphonate group-containing group.
The polynitrile compound of the invention is used as electrolyte, and can form a stable interfacial film at the interface of materials, and the film has good conductive lithium ion channels, so that collapse of the lithium ion channels is not generated in the circulating process, and the circulating and low-temperature performances are improved. In addition, at least a side chain functional group structure containing halogen is introduced, so that a thinner inorganic SEI film can be formed, SEI film sites are occupied, the problem of impedance increase caused by nitrile over-polymerization can be relieved, meanwhile, the SEI film is enriched and stabilized, transition metals in the anode material can be complexed, and therefore, the low-temperature and high-temperature storage performance can be improved.
As one embodiment of the present invention, R 1 ～R 2 Each independently selected from a fluoro-substituted C1-C3 alkyl group, a fluoro-substituted sulfonate group-containing group, a fluoro-substituted sulfone group-containing group, or a fluoro-substituted phosphonate group-containing group. The side chain functional group structure is introduced with sulfonate, sulfonyl, phosphonate and the like, and the enriched P, O, S and other elements enrich the electrode/electrolyte interface film component, so that the structural stability of the interface film can be further improved.
As one embodiment of the present invention, at least one selected from the group consisting of the compounds one to eight,
the second aspect of the present invention provides a nonaqueous electrolytic solution comprising a nonaqueous organic solvent, an electrolyte salt and an additive comprising the aforementioned polynitrile compound.
As a technical scheme of the invention, the polynitrile compound accounts for 0.1 to 5.0 percent of the sum of the mass of the nonaqueous organic solvent, the electrolyte salt and the additive. Preferably, the polynitrile compound accounts for 0.1 to 3.0% of the sum of the mass of the nonaqueous organic solvent, the electrolyte salt and the additive. As an example, the proportion of the polynitrile compound to the sum of the mass of the nonaqueous organic solvent, the electrolyte salt, and the additive may be, but is not limited to, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%.
As a technical scheme of the invention, the electrolyte salt accounts for 6-15% of the sum of the mass of the nonaqueous organic solvent, the electrolyte salt and the additive. Preferably, the electrolyte salt is 8-15%. As an example, the electrolyte salt may be 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% in ratio, but is not limited to. The electrolyte salt is selected from lithium hexafluorophosphate (LiPF) 6 ) Lithium perchlorate (LiClO) 4 ) Lithium tetrafluoroborate (LiBF) 4 ) Lithium methylsulfonate (LiCH) 3 SO 3 ) Lithium triflate (LiCF) 3 SO 3 ) Lithium bis (trifluoromethylsulfonyl) imide (LiN (CF) 3 SO 2 ) 2 ) Lithium dioxalate borate (C) 4 BLiO 8 ) Lithium difluorooxalato borate (C) 2 BF 2 LiO 4 ) Lithium difluorophosphate (LiPO) 2 F 2 ) Lithium difluorobis (oxalato) phosphate (LiDFBP), lithium bis (fluorosulfonyl) imide (LiWSI), and lithium bis (trifluoromethylsulfonyl) imide(LiTFSI).
As an embodiment of the present invention, the nonaqueous organic solvent is at least one of a chain carbonate, a cyclic carbonate and a carboxylic acid ester. Preferably, the nonaqueous organic solvent is a mixture of a chain carbonate and a cyclic carbonate. As an example, the nonaqueous organic solvent is selected from at least one of Ethylene Carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), propylene Carbonate (PC), butyl acetate (n-Ba), γ -butyrolactone (γ -Bt), propyl propionate (n-Pp), ethyl Propionate (EP), and ethyl butyrate (Eb). The non-aqueous organic solvent accounts for more than or equal to 80 percent, preferably more than or equal to 85 percent of the sum of the mass of the non-aqueous organic solvent, the electrolyte salt and the additive. By way of example, the nonaqueous organic solvent may be, but is not limited to, 80% > or more, 81% > or more, 82% > or more, 83% > or more, 84% > or more, 85% > or more, 86% > or more, 87% > or more, 88% > or more, 89% > or more, 90% or more, based on the sum of the nonaqueous organic solvent, electrolyte salt, and additive mass.
As an embodiment of the present invention, the additive further comprises a compound a. The compound A is at least one selected from ethylene carbonate (VC), ethylene carbonate (VEC), fluoroethylene carbonate (FEC), ethylene Sulfite (ES), 1, 3-Propane Sultone (PS) and ethylene sulfate (DTD). The compound A accounts for 0.1 to 10.0 percent of the sum of the mass of the nonaqueous organic solvent, the electrolyte salt and the additive. Preferably, the compound A accounts for 0.1 to 6.0% of the sum of the mass of the nonaqueous organic solvent, the electrolyte salt and the additive. As an example, the proportion of compound a to the sum of the mass of the nonaqueous organic solvent, the electrolyte salt, and the additive may be, but is not limited to, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0%, 10.0%.
The second aspect of the present invention provides a lithium ion battery comprising a positive electrode material, a negative electrode material, and a nonaqueous electrolyte. The lithium ion battery has better cycle life and high-temperature storage performance, and is favorable for further industrialized development of the lithium ion battery.
As a technical scheme of the invention, the positive electrode material is cobaltAn oxide material of the formula LiCo x M y O 2 Wherein 0.ltoreq.y<0.08, x+y is less than or equal to 1, M is at least one of Al, mg, zr and Ti.
As an aspect of the present invention, the anode material is selected from at least one of a carbon-based anode material, a titanium-based oxide anode material, and a silicon-based anode material.
As an aspect of the present invention, the negative electrode material may be selected from artificial graphite, natural graphite, hard carbon, soft carbon, lithium titanate, si material, silicon oxygen material, or silicon carbon material (10 wt.% Si).
Detailed Description
For a better description of the objects, technical solutions and advantageous effects of the present invention, the present invention will be further described with reference to specific examples. It should be noted that the following implementation of the method is a further explanation of the present invention and should not be taken as limiting the present invention.
Wherein, the specific conditions are not noted in the examples, and the method can be carried out according to the conventional conditions or the conditions suggested by manufacturers. The reagents or apparatus used were conventional products available commercially without the manufacturer's attention.
The following compounds one to eight of the present invention can be obtained by synthesis.
The synthetic route of the second compound can be the following route one.
The specific operation of the method can be as follows: 9.9g of malononitrile, 200g of anhydrous acetonitrile and 1.5g of triethylamine are added into a three-neck flask filled with nitrogen atmosphere and stirred uniformly, 33g of vinylsulfonyl fluoride is slowly added dropwise, then the mixture is reacted for 4 hours to obtain a dark red solution, the solution is concentrated, dichloromethane is added for extraction crystallization, a yellowish solid is obtained by filtration, and 38.5g of solid is obtained by vacuum drying at 120 ℃.
The compound I, the compound III and the compound IV are synthesized by using 75-02-5 CAS, 55444-21-8 CAS and 2050472-43-8 CAS to replace the vinylsulfonyl fluoride reference route I respectively.
The synthetic route for compound six may be route two as follows.
The specific operation of the method can be as follows: 16.1g of 1,3, 6-hexanetrinitrile, 100g of anhydrous acetonitrile and 1.5g of sodium tert-butoxide are added into a three-neck flask filled with nitrogen atmosphere, uniformly stirred, 12g of ethylene sulfonyl fluoride is slowly added dropwise, then the reaction is carried out for 24 hours, a dark red solution is obtained, the solution is concentrated, dichloromethane is added for extraction crystallization, a yellowish solid is obtained by filtration, 23g of solid is obtained by vacuum drying at 120 ℃, and the yield is 85%.
The compound five, the compound seven and the compound eight are respectively synthesized by using 75-02-5 CAS, 55444-21-8 CAS and 2050472-43-8 CAS to replace the vinylsulfonyl fluoride according to a route II.
Example 1
(1) Preparation of nonaqueous electrolyte: preparing an electrolyte in a vacuum glove box with the moisture content less than 1ppm under the argon atmosphere, mixing Ethylene Carbonate (EC) and diethyl carbonate (DEC) according to the weight ratio of EC to DEC=3:7 in the dry argon atmosphere glove box, adding a compound I, dissolving and fully stirring, adding lithium hexafluorophosphate, and uniformly mixing to obtain the electrolyte.
(2) Preparation of positive electrode: liCo is added to 0.9 Zr 0.1 O 2 Uniformly mixing an adhesive PVDF and a conductive agent SuperP according to a mass ratio of 97:1:2 to prepare lithium ion battery anode slurry with certain viscosity, coating the mixed slurry on two sides of an aluminum foil, and drying and rolling to obtain the anodeAnd (3) a sheet.
(3) Preparation of the negative electrode: preparing a silicon-carbon anode material (10 wt.% Si), a conductive agent SuperP, a thickener CMC and an adhesive SBR (styrene butadiene rubber emulsion) into slurry according to the mass ratio of 96:1:1:2, uniformly mixing, coating the mixed slurry on two sides of a copper foil, and drying and rolling to obtain the anode sheet.
(4) Preparation of a lithium ion battery: and (3) preparing the positive plate, the diaphragm and the negative plate into square battery cells in a lamination mode, packaging by adopting polymers, filling the prepared lithium ion battery nonaqueous electrolyte, and preparing the lithium ion battery with the capacity of 1400mAh through the procedures of formation, capacity division and the like.
The electrolyte formulations of examples 1 to 14 and comparative examples 1 to 8 are shown in Table 1, and the procedure for preparing the electrolytes and preparing the batteries of examples 2 to 14 and comparative examples 1 to 8 are the same as in example 1.
Table 1 electrolyte components of examples and comparative examples
The lithium ion batteries manufactured in examples 1 to 14 and comparative examples 1 to 10 were subjected to a normal temperature cycle test, a high temperature storage test, and a low temperature discharge test, respectively, under the following specific test conditions, and the test results are shown in table 2.
(1) Normal temperature cycle test
Lithium ion batteries were charged and discharged once at 1.0C/1.0C (battery discharge capacity C0) under normal temperature (25 ℃) and at an upper limit voltage of 4.5V, and then charged and discharged at 1..0C/1.0C for 500 weeks under normal temperature (battery discharge capacity C1).
Capacity retention= (C1/C0) ×100%.
(2) High temperature cycle test of lithium ion battery
Charging and discharging the lithium ion battery at 1.0C/1.0C (the discharge capacity of the battery is C0) at an excessively high temperature (45 ℃) with an upper limit voltage of 4.5V, then charging and discharging the lithium ion battery at 1.0C/1.0C for 300 weeks (the discharge capacity of the battery is C1) at normal temperature,
capacity retention = (C1/C0) ×100%
(3) High temperature storage test
Lithium ion batteries were charged and discharged at 0.3C/0.3C once (the discharge capacity of the battery was recorded as C) at normal temperature (25 ℃ C.) 0 ) The upper limit voltage is 4.5V. Placing the battery in an oven at 85 ℃ for 6 hours, taking out the battery, placing the battery in an environment at 25 ℃ for 0.3C discharging, and recording the discharge capacity as C 1 . The lithium ion battery was then charged and discharged once at 0.3C/0.3C (the discharge capacity of the battery was recorded as C) 2 )。
Capacity retention= (C 1 /C 0 )*100％
Capacity recovery rate= (C 2 /C 0 )*100％
Low temperature discharge test
Lithium ion batteries were charged and discharged at 0.3C/0.3C once (the discharge capacity of the battery was recorded as C) at normal temperature (25 ℃ C.) 0 ) The upper limit voltage is 4.5V. Placing the battery in an oven at-20 ℃ for 4 hours, discharging the battery at 0.3C, and recording the discharge capacity as C 1 The cut-off voltage was 3.0V.
Capacity retention= (C 1 /C 0 )*100％
Table 2 lithium ion battery performance test results
As can be seen from the results of table 2, the use of the polynitrile compound of the present invention as an additive can greatly improve the cycle performance, high temperature storage and low temperature discharge performance of a battery, since the polynitrile compound can not only form a stable interfacial film at the interface of a material, but also introduce a side chain functional group structure containing at least halogen, which can form a thinner inorganic SEI film, occupy the SEI film sites, alleviate the problem of increased resistance caused by excessive nitrile polymerization, and simultaneously enrich and stabilize the SEI film and complex transition metals in the positive electrode material, thus improving the low temperature and high temperature storage performance.
As is clear from comparative examples 1 to 4 and examples 5 to 8, the selected polynitrile compounds have sulfonate groups, sulfone groups and phosphonate groups introduced into the side chain functional group structure, and the battery performance is better, which may further improve the structural stability of the interfacial film due to the enrichment of P, O, S and other elements which enrich the electrode/electrolyte interfacial film components.
As can be seen from comparative example 1, examples 12 to 14 and comparative examples 2 to 4, the lithium ion battery performs best when compound a is reintroduced based on the polynitrile compound, especially when compound a contains both VC and FEC, which may be due to the synergistic effect of VC, FEC and polynitrile compound: the inorganic SEI formed by FEC has stronger toughness, the organic SEI formed by VC polymerization has better heat stability, the polynitrile compound can be adsorbed at an electrode interface to form an inorganic SEI and an organic adsorption layer, the inorganic SEI is further optimized, the organic interface stability is improved, and the performance of the battery is remarkably improved.
As is clear from a comparison of example 5 and comparative example 5, although the structure of Compound No. nine of comparative example 5 is similar to that of Compound No. five of example 5, the SEI film formed by the dinitrile compound has a large resistance, and the halogen-free side chain functional group structure alleviates the problem of increased resistance, so that the battery performance is poor.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the present invention can be modified or substituted without departing from the spirit and scope of the technical solution of the present invention.

Claims (10)

1. A polynitrile compound is characterized in that the structural formula is shown as a structural formula I or a structural formula II,
wherein R is 1 ～R 2 Each independently selected from the group consisting of halogen, halogen-substituted C1-C6 hydrocarbyl, halogen-substituted sulfonate group-containing group, halogen-substituted sulfone group-containing group, and halogen-substituted phosphonate group-containing group.
2. The polynitrile compound according to claim 1, wherein R 1 ～R 2 Each independently selected from a fluoro-substituted C1-C3 alkyl group, a fluoro-substituted sulfonate group-containing group, a fluoro-substituted sulfone group-containing group, or a fluoro-substituted phosphonate group-containing group.
3. The polynitrile compound according to claim 1, wherein at least one selected from the group consisting of compound one to compound eight,
4. a nonaqueous electrolytic solution comprising a nonaqueous organic solvent, an electrolyte salt and an additive, characterized in that the additive comprises the polynitrile compound according to any one of claims 1 to 3.
5. The nonaqueous electrolytic solution according to claim 4, wherein the polynitrile compound is 0.1 to 5.0% of the sum of the mass of the nonaqueous organic solvent, the mass of the electrolyte salt and the mass of the additive.
6. The nonaqueous electrolytic solution according to claim 4, wherein the electrolyte salt is at least one selected from the group consisting of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium methylsulfonate, lithium trifluoromethylsulfonate, lithium bistrifluoromethylsulfonimide, lithium dioxaborate, lithium difluorooxalato borate, lithium difluorophosphate, lithium difluorobisoxalato phosphate, lithium bisfluorosulfonylimide and lithium bistrifluoromethylsulfonimide.
7. The nonaqueous electrolytic solution according to claim 4, wherein the nonaqueous organic solvent is at least one selected from the group consisting of a chain carbonate, a cyclic carbonate and a carboxylic acid ester.
8. The nonaqueous electrolytic solution according to claim 4, wherein the additive further comprises a compound a selected from at least one of vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, ethylene sulfite, 1, 3-propane sultone and ethylene sulfate.
9. A lithium ion battery comprising a positive electrode material, a negative electrode material, and the nonaqueous electrolytic solution according to any one of claims 4 to 8.
10. The lithium ion battery of claim 9, wherein the positive electrode material is a cobalt oxide material having a chemical formula of LiCo x M y O 2 Wherein 0.ltoreq.y<0.08, x+y is less than or equal to 1, M is at least one of Al, mg, zr and Ti.
CN202310487988.8A 2023-05-04 2023-05-04 Polynitrile compound, nonaqueous electrolyte and lithium ion battery Pending CN116514681A (en)

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