CN117096437A - Nonaqueous electrolyte and lithium ion battery - Google Patents

Nonaqueous electrolyte and lithium ion battery Download PDF

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Publication number
CN117096437A
CN117096437A CN202310888327.6A CN202310888327A CN117096437A CN 117096437 A CN117096437 A CN 117096437A CN 202310888327 A CN202310888327 A CN 202310888327A CN 117096437 A CN117096437 A CN 117096437A
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lithium
group
additive
nonaqueous electrolyte
nonaqueous
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Inventor
曾艺安
毛冲
王霹霹
李海星
冯慧涛
莫德欢
潘东优
谢金鑫
戴晓兵
冯攀
韩晖
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Huainan Saiwei Electronic Materials Co ltd
Hefei Saiwei Electronic Materials Co ltd
Zhuhai Smoothway Electronic Materials Co Ltd
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Huainan Saiwei Electronic Materials Co ltd
Hefei Saiwei Electronic Materials Co ltd
Zhuhai Smoothway Electronic Materials Co Ltd
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Priority to CN202310888327.6A priority Critical patent/CN117096437A/en
Publication of CN117096437A publication Critical patent/CN117096437A/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
    • 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
    • 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
    • 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
    • H01M2300/0042—Four or more solvents

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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)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Secondary Cells (AREA)

Abstract

The invention discloses a nonaqueous electrolyte and a lithium ion battery, wherein the nonaqueous electrolyte comprises a nonaqueous organic solvent, lithium salt and an additive, the additive comprises a compound A shown in a formula 1,wherein R is 1 Selected from fluorine, chlorine or p-tolyl, R 2 、R 3 、R 4 、R 5 、R 6 Each independently selected from the group consisting of hydrogen atom, cyano group, nitro group, halogen atom, trifluoromethyl group, amino group, hydroxyl group, carboxyl group, C 1 ‑C 3 Alkyl, tert-butyl, benzyl, sulfonyl fluoride, C 1 ‑C 4 Alkoxy, C 2 ‑C 4 Alkenyl, C 2 ‑C 4 Alkynyl or C of (2) 1 ‑C 4 Acyl groups of (a). The additive of the invention can accelerate the dissociation of lithium salt and acid radical ion, thereby improving the ion electricity of the electrolyteConductivity; the additive can generate stable S-Li bond in situ when forming SEI film, so that SEI film stability is improved; in addition, the additive also makes the structure of the positive electrode material more stable. Therefore, the nonaqueous electrolyte can improve the high-low temperature performance of the lithium ion battery.

Description

Nonaqueous electrolyte and lithium ion battery
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a non-aqueous electrolyte and a lithium ion battery.
Background
Lithium ion batteries are one of the most common batteries in the market at present, and the positive electrode material mainly comprises spinel lithium manganate (LiMn 2 O 4 ) Lithium iron phosphate (LiFePO) 4 ) Lithium cobalt oxide (LiCoO) 2 ) And ternary cathode material (LiNi 1/3 Co 1/3 Mn 1/3 O 2 、LiNi 0.5 Co 0.2 Mn 0.3 O 2 、LiNi 0.6 Co 0.2 Mn 0.2 O 2 And LiNi 0.8 Co 0.1 Mn 0.1 O 2 ) Etc., wherein the ternary positive electrode material has high energyThe advantages of high volume density, high capacity, long service life and the like are widely applied to the fields of mobile phones, portable computers, electric automobiles, aerospace and the like.
The capacity of the ternary positive electrode material is mainly derived from Ni 2+ /Ni 4+ The higher the nickel content, the greater the capacity of the material, but after the Ni content is increased, the ternary positive electrode material can bring about a series of troublesome technical problems. Such as LiNi 0.8 Co 0.1 Mn 0.1 O 2 The anode material has the problem of cation mixed arrangement, namely, the outer layer electron arrangement of the material is t in the sintering process due to higher nickel content 2g 6 e g 2 Ni of (2) 2+ Is easy to be distributed with the outer electron as t 2g 6 e g 1 Ni of (2) 3+ Coexistence of Ni in addition 2+ Radius of radiusWith Li + Radius->Very close, leading to Ni 2+ May occupy Li + 3b position of space, li + May occupy Ni 2+ In the 3a position of (2), lithium and nickel ions are mixed and discharged, and particularly when lithium removal occurs in the positive electrode, the lithium ion is mixed with Li + Is continuously separated from the positive electrode material, ni 2+ Will gradually migrate to Li + The formation of NiO phase in the positive electrode material is caused, so that the structure of the positive electrode material becomes unstable, collapse and damage of the structure are seriously possibly caused, and great resistance is generated when lithium intercalation is carried out subsequently. In addition, when the structure of the positive electrode material is broken, the eluted Ni 2+ 、Co 3+ 、Mn 4+ The electrolyte is catalyzed to be decomposed continuously, and the additive is consumed continuously, so that the battery has poor high-temperature storage and serious cyclic gas production.
Therefore, there is a need to develop a nonaqueous electrolyte solution that matches the high nickel ternary cathode material to solve the deficiencies of the prior art.
Disclosure of Invention
The invention aims to provide a non-aqueous electrolyte which can remarkably improve the normal temperature cycle performance, the high temperature storage performance and the low temperature discharge performance of a lithium ion battery.
Another object of the present invention is to provide a lithium ion battery having superior normal temperature cycle performance, high temperature storage performance, and low temperature discharge performance.
In order to achieve the above object, the present invention provides a nonaqueous electrolytic solution comprising a nonaqueous organic solvent, a lithium salt and an additive comprising a compound A represented by formula 1,
wherein R is 1 Selected from fluorine, chlorine or p-tolyl, R 2 、R 3 、R 4 、R 5 、R 6 Each independently selected from the group consisting of hydrogen atom, cyano group, nitro group, halogen atom, trifluoromethyl group, amino group, hydroxyl group, carboxyl group, C 1 -C 3 Alkyl, tert-butyl, benzyl, sulfonyl fluoride, C 1 -C 4 Alkoxy, C 2 -C 4 Alkenyl, C 2 -C 4 Alkynyl or C of (2) 1 -C 4 Acyl groups of (a).
Compared with the prior art, the additive is a zwitterionic compound, the structure of the additive comprises a sulfonyl imide group and a pyridine ring, negative charges are mainly concentrated on nitrogen atoms connected with sulfur atoms, positive charges are concentrated on the nitrogen atoms on the pyridine ring, and the sulfonyl imide group is connected with the pyridine ring through a carbonyl group, so that the additive interacts with lithium salt in electrolyte, the dissociation of the lithium salt and acid radical ions is accelerated, and the ionic conductivity of the electrolyte is improved; in addition, due to the instability of the S-N bond in the additive structure, the stable S-Li bond can be generated in situ when the SEI film is formed, and the stability of the SEI film is improved; in addition, two nitrogen atoms in the additive structure align with Li in the positive electrode material + 、Ni 2+ 、Co 3+ 、Mn 4+ Has a oneThe structure of the positive electrode material is more stable due to the complexation to a certain degree. Therefore, the additive can obviously improve the normal temperature cycle performance, the high temperature storage performance and the low temperature discharge performance of the lithium ion battery.
Preferably, R of the present invention 2 、R 3 、R 4 、R 5 、R 6 Each independently selected from the group consisting of hydrogen, cyano, fluorine, trifluoromethyl, methyl, sulfonyl fluoride, vinyl, ethynyl, or formyl.
Preferably, the compound a of the present invention is at least one selected from the group consisting of compounds 1 to 11:
preferably, the mass of the additive accounts for 0.1-2% of the total mass of the nonaqueous electrolyte. Specifically, the mass of the additive of the present invention may be, but not limited to, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2% of the total mass of the nonaqueous electrolytic solution.
Preferably, the lithium salt of the present invention is selected from lithium hexafluorophosphate (LiPF 6 ) Lithium tetrafluoroborate (LiBF) 4 ) Lithium perchlorate (LiClO) 4 ) Lithium bis (fluorosulfonyl) imide (LiLSI), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium difluoro (oxalato) borate (C) 2 BF 2 LiO 4 ) Lithium bisoxalato borate (C) 4 BLiO 8 ) Lithium difluorophosphate (LiPO) 2 F 2 ) And at least one of lithium difluorobis oxalato phosphate (LiDFBP). Specifically, the lithium salt of the present invention accounts for 5 to 25% of the total mass of the nonaqueous electrolytic solution, and specifically may be, but not limited to, 5%, 7.5%, 8%, 10%, 13%, 15.6%, 16%, 17%, 19%, 21%, 23%, 24%, 25%. Preferably, the mass of the lithium salt of the present invention accounts for 12.5% of the total mass of the nonaqueous electrolytic solution.
Preferably, the lithium salt of the present invention is lithium hexafluorophosphate. Compared with other lithium salts, the additive provided by the invention has the strongest interaction with lithium hexafluorophosphate, and can obviously accelerate the dissociation of lithium ions and hexafluorophosphate, so that the ionic conductivity of the electrolyte is improved.
Preferably, the nonaqueous organic solvent of the present invention is 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 (PP), ethyl Propionate (EP), and ethyl butyrate (Eb). Specifically, the nonaqueous organic solvent is a mixture of ethylene carbonate, methyl ethyl carbonate and diethyl carbonate. Preferably, the nonaqueous organic solvent of the present invention consists of ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a mass ratio of 1:1:1.
Preferably, the nonaqueous electrolytic solution of the present invention further comprises a film forming auxiliary agent selected from at least one of Vinylene Carbonate (VC), vinylene carbonate (VEC), fluoroethylene carbonate (FEC), ethylene Sulfite (ES), 1, 3-Propane Sultone (PS), and ethylene sulfate (DTD). Specifically, the mass of the film forming additive accounts for 0.1-6% of the total mass of the nonaqueous electrolyte. More specifically, the film forming auxiliary agent of the present invention may be 0.1%, 0.8%, 1.2%, 1.5%, 2%, 2.5%, 3%, 3.6%, 4%, 4.2%, 4.5%, 4.8%, 5.2%, 5.5%, 5.8%, 6% by mass based on the total mass of the nonaqueous electrolytic solution.
Preferably, the film forming aid of the present invention is a mixture of 1, 3-propane sultone and fluoroethylene carbonate. Preferably, the film forming aid of the present invention consists of 1, 3-propane sultone and fluoroethylene carbonate in a mass ratio of 1:5.
In order to achieve the above object, the present invention also provides a lithium ion battery, comprising a positive electrode, a negative electrode, and the above-mentioned non-aqueous electrolyte, wherein the positive electrode is LiNi x Co y Mn( 1-x-y )M z O 2 Wherein 0.6.ltoreq.x<0.9, x+y is less than or equal to 1, M is at least one of Al, mg, zr, ti, and z is more than or equal to 0<0.08。
Compared with the prior art, the lithium ion battery comprises the additive with the structure shown in the formula 1, wherein the formula 1 is a zwitterionic compound, and the additive interacts with lithium salt in electrolyte to accelerate the dissociation of the lithium salt and acid radical ionsAnd the ionic conductivity of the electrolyte is improved; in addition, due to the instability of the S-N bond in the additive structure, the stable S-Li bond can be generated in situ when the SEI film is formed, and the stability of the SEI film is improved; in addition, two nitrogen atoms in the additive structure align with Li in the positive electrode material + 、Ni 2+ 、Co 3+ 、Mn 4+ The lithium ion battery has a certain degree of complexation, so that the structure of the positive electrode material is more stable, and therefore, the lithium ion battery has better normal temperature cycle performance, high temperature storage performance and low temperature discharge performance.
Preferably, x=0.8, y=0.1, m is Zr, and z=0.03.
Preferably, the anode of the present invention is made of a carbon anode material, a silicon anode material or a silicon carbon anode material. Preferably, the anode is made of a silicon-carbon anode material, and the mass ratio of silicon to carbon is 1:9.
Detailed Description
In order to further illustrate the objects, technical solutions and advantageous effects of the present invention, the present invention will be further described with reference to specific examples. The specific conditions not specified in examples and comparative examples may be carried out under the conventional conditions or the conditions recommended by the manufacturer, and the reagents or instruments used are conventional products available commercially without specifying the manufacturer.
Specifically, the compounds 1 to 11 of the present invention can be prepared by the synthetic routes shown below:
example 1
Preparing a nonaqueous electrolyte:
in a glove box filled with nitrogen (the water content is less than or equal to 1ppm and the oxygen content is less than or equal to 1 ppm), respectively dehydrating Ethylene Carbonate (EC), methyl ethyl carbonate (EMC) and diethyl carbonate (DEC) by using a 4A molecular sieve after 5% solution mass activation to ensure that the water content of the solution is less than or equal to 1ppm, uniformly mixing EC, EMC, DEC according to a mass ratio of 1:1:1 to obtain 81g of solution A, adding 0.5g of compound 1, 1g of Vinylene Carbonate (VC) and 5g of fluoroethylene carbonate (FEC) into the solution A, slowly adding 12.5g of lithium hexafluorophosphate, and uniformly stirring to completely dissolve the solution to form a nonaqueous electrolyte.
Preparation of positive electrode:
LiNi is added to 0.8 Co 0.1 Mn 0.1 Zr 0.03 O 2 Uniformly mixing a material, an adhesive PVDF and a conductive agent Super P according to a mass ratio of 97:1:2 to prepare slurry, coating the slurry on two sides of an aluminum foil, and drying and rolling to obtain the anode.
Preparation of the negative electrode:
uniformly mixing a silicon-carbon negative electrode (Si: C=1:9), a conductive agent SuperP, a thickener CMC and an adhesive SBR (styrene butadiene rubber emulsion) according to a mass ratio of 95:2:1:2 to prepare slurry, coating the slurry on two sides of a copper foil, and then drying and rolling to obtain the negative electrode.
Preparation of a lithium ion battery:
and preparing the positive electrode, the diaphragm and the negative electrode lamination into square battery cells, packaging by adopting polymers, then injecting nonaqueous electrolyte into the battery cells in a glove box, and preparing the lithium ion battery with the capacity of 1000mAh through the procedures of formation, capacity division and the like.
The electrolyte compositions of examples 1 to 14 and comparative examples 1 to 2 are shown in Table 1, and examples 2 to 14 are identical to those of comparative examples 1 to 2 in terms of nonaqueous electrolyte preparation, positive and negative electrode preparation, and lithium ion battery preparation.
TABLE 1 electrolyte composition
The lithium ion batteries prepared in examples 1 to 14 and comparative examples 1 to 2 were subjected to a normal temperature cycle test, a high temperature storage test, and a low temperature discharge performance test, respectively, according to the following test conditions, and the test results are shown in table 2.
And (3) normal temperature cyclic test:
the lithium ion battery is charged and discharged at the normal temperature (25 ℃) at 1.0C/1.0C (the discharge capacity of the battery is C) 0 ) The upper limit voltage was 4.4V, and then charging and discharging at 1.0C/1.0C was performed for 500 weeks under normal temperature conditions (the discharge capacity of the battery was C) 1 )。
Capacity retention= (C 1 /C 0 )*100％。
High temperature cycle test:
the lithium ion battery is charged and discharged at 1.0C/1.0C once under the condition of high temperature (45 ℃) (the discharge capacity of the battery is C) 0 ) The upper limit voltage was 4.4V, and then charging and discharging at 1.0C/1.0C was performed for 300 weeks under normal temperature conditions (the battery discharge capacity was C) 1 )。
Capacity retention= (C 1 /C 0 )*100％。
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 4.4V; placing the battery in a 60 ℃ oven for 15d storage, taking out the battery, recovering the battery to room temperature, placing the battery in a 25 ℃ environment, discharging at 0.3C, and recording the discharge capacity as C 1 Then the lithium ion battery was 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 4.4V; the cell was left to stand at-20℃for 4 hours, and 0.3C discharge was performed on the cell, and the discharge capacity was recorded as C 1 The cut-off voltage was 3.0V.
Capacity ofRetention = (C 1 /C 0 )*100％。
TABLE 2 Performance test results
Comparing examples 1 to 13 with comparative example 1, it is known that the lithium ion battery of the present invention has relatively good normal temperature cycle performance, high temperature cycle performance, low temperature discharge performance and high temperature storage performance, because the additive of the present invention is a zwitterionic compound, the structure of the additive comprises a sulfonimide group and a pyridine ring, negative charges are mainly concentrated on a nitrogen atom connected with a sulfur atom, positive charges are concentrated on a nitrogen atom on the pyridine ring, and the sulfonimide group is connected with the pyridine ring through a carbonyl group, so that the additive interacts with lithium salt in an electrolyte, and dissociation of the lithium salt and acid radical ions is accelerated, thereby improving ionic conductivity of the electrolyte; in addition, due to the instability of the S-N bond in the additive structure, the stable S-Li bond can be generated in situ when the SEI film is formed, and the stability of the SEI film is improved; in addition, two nitrogen atoms in the additive structure align with Li in the positive electrode material + 、Ni 2+ 、Co 3+ 、Mn 4+ The complex effect is achieved to a certain extent, so that the structure of the positive electrode material is more stable. Therefore, the non-aqueous electrolyte provided by the invention can obviously improve the normal temperature cycle performance, the high temperature storage performance and the low temperature discharge performance of the lithium ion battery.
Comparing examples 1-11, it is known that the various properties of the lithium ion battery are also affected to different degrees by adjusting the substituents with different functions on the pyridine ring, and more specifically, the various properties of the lithium ion battery of example 4 are optimal, which indicates that introducing 5 fluorine atoms on the pyridine ring can improve the wettability of the electrolyte to the cathode material to the greatest extent, and can form an SEI film with more LiF components at the formation stage of the battery, so that the SEI film has a more stable structure and higher strength, and the normal temperature cycle, the high temperature cycle, the low temperature discharge and the high temperature storage property of the lithium ion battery are improved to the greatest extent.
As can be seen from comparison of examples 1, 6 and 7, the introduction of unsaturated carbon-carbon double bond and carbon-carbon triple bond into pyridine ring can also significantly improve high and low temperature performance of lithium ion battery, because the introduced unsaturated double bond or triple bond is polymerized in situ on SEI film to form a protective film, structure of SEI film is not easily damaged in continuous charge and discharge process, and exposed N is contained on chain end after polymerization + And N - Atoms, also can accelerate Li + And the lithium ion battery is transmitted in the SEI film, so that the low-temperature capacity retention rate of the lithium ion battery is high.
As can be seen from comparison of examples 1 and 9, the introduction of the fluorosulfonyl group into the pyridine ring can also significantly improve the high and low temperature performance of the lithium ion battery, because the introduced fluorosulfonyl group is a strong electron withdrawing group, which can enable the charges on the pyridine ring to be more dispersed, and the structure of the compound to be more stable. In addition, in the charge and discharge cycle process of the battery, the fluorosulfonyl radical is generated along with the homolytic cleavage of the S-C bond, the activity of the fluorosulfonyl radical is high, oxygen atoms in the electrolyte solvent can be extracted to generate lithium fluorosulfonate, and the lithium fluorosulfonate has a simple molecular structure, high stability and high conductivity, so that the high-low temperature performance of the lithium ion battery can be improved.
Comparing example 1 with example 13, it can be seen that when compound 1 is combined with PS, the high and low temperature performance of the battery is significantly improved, and the reason is probably that the compound 1 and PS have similar action mechanisms, are preferentially reduced at the negative electrode, form a compact passivation film at the negative electrode, and improve the high and low temperature performance of the battery.
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 nonaqueous electrolyte comprising a nonaqueous organic solvent, a lithium salt and an additive, characterized in that the additive comprises a compound A represented by formula 1,
wherein R is 1 Selected from fluorine, chlorine or p-tolyl, R 2 、R 3 、R 4 、R 5 、R 6 Each independently selected from the group consisting of hydrogen atom, cyano group, nitro group, halogen atom, trifluoromethyl group, amino group, hydroxyl group, carboxyl group, C 1 -C 3 Alkyl, tert-butyl, benzyl, sulfonyl fluoride, C 1 -C 4 Alkoxy, C 2 -C 4 Alkenyl, C 2 -C 4 Alkynyl or C of (2) 1 -C 4 Acyl groups of (a).
2. The nonaqueous electrolyte according to claim 1, wherein R 2 、R 3 、R 4 、R 5 、R 6 Each independently selected from the group consisting of hydrogen, cyano, fluorine, trifluoromethyl, methyl, sulfonyl fluoride, vinyl, ethynyl, or formyl.
3. The nonaqueous electrolyte according to claim 1, wherein the compound a is at least one selected from the group consisting of compounds 1 to 11:
4. the nonaqueous electrolytic solution according to claim 1, wherein the additive accounts for 0.1 to 2% by mass of the total mass of the nonaqueous electrolytic solution.
5. The nonaqueous electrolytic solution according to claim 1, wherein the lithium salt is at least one selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium bis-fluorosulfonimide, lithium bis-trifluoromethanesulfonyl imide, lithium difluorooxalato borate, lithium bis-oxalato borate, lithium difluorophosphate and lithium difluorobisoxalato phosphate.
6. The nonaqueous electrolyte of claim 1, wherein said lithium salt is lithium hexafluorophosphate.
7. The nonaqueous electrolyte according to claim 1, wherein the nonaqueous organic solvent is a mixture of ethylene carbonate, ethylmethyl carbonate and diethyl carbonate.
8. The nonaqueous electrolytic solution of claim 1, further comprising a film forming aid selected from at least one of vinylene carbonate, fluoroethylene carbonate, ethylene sulfite, 1,3 propane sultone and ethylene sulfate.
9. The nonaqueous electrolytic solution according to claim 8, wherein said film-forming auxiliary agent is a mixture of 1, 3-propane sultone and fluoroethylene carbonate.
10. A lithium ion battery comprising a positive electrode and a negative electrode, and further comprising the nonaqueous electrolyte according to any one of claims 1 to 9, wherein the positive electrode is LiNi x Co y Mn( 1-x-y )M z O 2 Wherein 0.6.ltoreq.x<0.9, x+y is less than or equal to 1, M is at least one of Al, mg, zr, ti, and z is more than or equal to 0<0.08。
CN202310888327.6A 2023-07-19 2023-07-19 Nonaqueous electrolyte and lithium ion battery Pending CN117096437A (en)

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