JP7455105B2 - Non-aqueous electrolyte for lithium ion batteries and its use - Google Patents

Description

The present invention belongs to the field of batteries, and specifically relates to non-aqueous electrolytes for lithium ion batteries and their use.

With the widespread use of lithium-ion batteries in life, production, energy storage and military industrial fields, the safety performance of batteries is one of the important factors promoting its further development, and many lithium-ion batteries, especially Soft-pack batteries are prone to short circuits during high-temperature storage or high-temperature charging/discharging processes, which can cause fires. One of the reasons why lithium-ion batteries tend to cause fires during high-temperature storage and during the charging and discharging process is that lithium dendrites break through the separator, causing a short circuit inside the battery and instantly accumulating a large amount of heat in a certain space. This is because the separator is ignited. Another reason is that the internal side reactions of the battery increase in the high temperature environment, the electrolyte decomposes and generates gas, causing the battery shell to burst, leading to the reaction of metallic lithium with oxygen or water vapor, which is also May cause fire. In addition, since solid electrolyte interface (SEI) easily decomposes in high-temperature environments, excess lithium ions are involved in the SEI film formation process, which reduces the amount of lithium ions released from the negative electrode and further reduces capacity. leading to a decrease in

To improve the electrochemical performance of lithium-ion batteries, many researchers have added various types of additives to the electrolyte, such as Vinylene Carbonate (VC) and 4-Fluoro-1 , 3-dioxolan-2-one, FEC) improves the performance of the battery. However, the addition of additives causes new problems, for example, the addition of FEC makes the battery more likely to generate gas during the high-temperature charging and discharging process, causing battery expansion, which affects the electrochemical performance of the additive and the battery. It is necessary to balance the relationship with

CN108598461A discloses an electrolyte containing a cyclic siloxane phosphate additive, which forms a stable solid electrolyte film on the surface of high nickel cathode material during the charging process and prevents the generation of interfacial gas. By suppressing this, the stability of the structure of the positive electrode material can be further improved. However, although the above content can further reduce the impedance of the solid electrolyte membrane, it is necessary to further improve the high temperature cycle performance and capacity retention rate of the lithium ion battery.

CN106030889A discloses a nonaqueous electrolyte for secondary batteries, which reduces the initial irreversible capacity and improves the first cycle efficiency of secondary batteries by adding a cyclic carbonate additive with a specific structure. It not only improves the high temperature cycling characteristics of the battery, but not the rate performance. CN103493280A discloses a non-aqueous electrolyte containing a cyclic sulfonate that can extend the operating temperature range of a secondary battery, but not in terms of cycle performance and rate performance.

Therefore, in this field, there is a need to develop a non-aqueous electrolyte that has good cycle performance, high-temperature storage performance, and cycle performance for lithium-ion batteries, and a lithium-ion battery containing the non-aqueous electrolyte that has excellent overall performance. desired.

In view of the lack of prior art, an object of the present invention is to provide a non-aqueous electrolyte for lithium ion batteries and its use. The present invention makes it possible to form a stable SEI film on both the surfaces of the positive and negative electrode materials by adding an alkenylsiloxane compound to the electrolyte and using it in combination with other additives. The SEI membrane has good ion conduction performance, can reduce the impedance and capacity decay rate of lithium ion batteries, and can maintain good capacity retention and recovery rate in high temperature storage environment and small volume expansion of batteries. can.

In order to achieve the purpose of the invention, the present invention adopts the following technical solution.
In a first aspect, the present invention provides a nonaqueous electrolyte for a lithium ion battery, the nonaqueous electrolyte for a lithium ion battery comprising a lithium salt, a nonaqueous solvent, and an additive, the additive having the formula Contains an alkenylsiloxane compound having a cyclic structure shown in (1), an impedance reducing additive, and a film forming additive.

However, R is hydrogen, halogen, cyano group, substituted or unsubstituted C1 to C5 alkyl group, substituted or unsubstituted C6 to C30 aryl group, amide group, phosphate ester group, sulfonyl group, siloxy group, or boron. selected from acid ester groups, and n is an integer from 2 to 10.

In the present invention, an alkenylsiloxane compound having a cyclic structure represented by formula (1) is used in combination with a film-forming additive, and the double bond of the alkenyl group is broken at the early stage of the electrochemical reaction process, resulting in a positive electrode. A dense SEI film can be formed on the surface of the negative electrode material, and by increasing the density and stability of the SEI film, it becomes less likely to be destroyed under high temperature conditions, and at the same time reduces the amount of active lithium ions consumed, which improves lithium ion batteries. On the other hand, when used in combination with impedance reducing additives, it can improve the ion conduction performance and ion transport speed of the SEI membrane, reduce the impedance of the battery, and reduce the internal polarization and lithium dendrite of the battery. This not only improves the problem of internal impedance increase and gas generation due to electrolyte consumption, but also suppresses the volumetric expansion of the battery. In addition, the -Si-O- bond can complex the metal ions eluted from the positive electrode, further reducing the influence of the metal ions on the catalytic reaction of the electrolyte, and the Si atoms can highly absorb fluorine ions. The hydrolysis of fluorine-containing lithium salts can also be suppressed.

In the present invention, R is selected from hydrogen, halogen, cyano group, substituted or unsubstituted C1-C5 alkyl group, substituted or unsubstituted C6-C30 aryl group, for example, hydrogen, halogen, cyano group, It may be a methyl group, a propyl group, a substituted butyl group or a phenyl group, but it is not limited to the types listed, and other types not listed within the range of substituents are also applicable.

Preferably, R is a cyano group, a methyl group, an ethyl group, a propyl group, a phenyl group, or

However, the wavy line represents the bonding site of the group, for example, R is a cyano group, a methyl group, an ethyl group, a propyl group, a phenyl group, or

It may be.

Preferably, the alkenylsiloxane compound having a cyclic structure represented by formula (1) is any one of the following compounds.

Preferably, the alkenylsiloxane compound having a cyclic structure represented by the formula (1) is any one of the above compounds, for example, any one of T01, T02, T03, T04, T05, or T06. You can.

Preferably, the content of the alkenylsiloxane compound having a cyclic structure represented by formula (1) in the nonaqueous electrolyte of the lithium ion battery has a mass percentage of 0.01 to 5.00%, for example, 0.01%. %, 0.05%, 0.10%, 0.50%, 1.00%, 2.00%, 4.00% or 5.00%, but are limited to the numbers listed. The same applies to other numerical values not listed within the numerical range.

Preferably, the nonaqueous electrolyte of the lithium ion battery further includes an impedance reducing additive, and the impedance reducing additive is any one or at least two of lithium difluorophosphate, ethylene sulfate, and lithium difluoro(oxalato)borate. For example, lithium difluorophosphate, ethylene sulfate, lithium difluoro(oxalato)borate, or a combination of ethylene sulfate and lithium difluoro(oxalato)borate.

When the additive of the alkenylsiloxane compound having a cyclic structure in the present invention is used in combination with one or more of lithium difluorophosphate, vinylene carbonate, and lithium difluoro(oxalato)borate, the denseness and stability of the SEI film can be improved. It not only increases and improves the stability of high temperature cycles, but also reduces the impedance of the battery and suppresses the problem of gas generation and volumetric expansion of the battery.

Preferably, the content of the impedance reducing additive in the nonaqueous electrolyte of the lithium ion battery has a mass percentage of 0.01 to 10.00%, for example, 0.01%, 0.05%, 1.00%. %, 3.00%, 6.00%, 8.00% or 10.00%, but is not limited to the listed numbers, and may also include other numbers not listed within the numerical range. The same applies.

Preferably, the nonaqueous electrolyte of the lithium ion battery further includes a film-forming additive, and the film-forming additive includes propylene sulfate, 1,3-propane sultone, vinylene carbonate, vinylethylene carbonate, fluoroethylene carbonate, propene sultone. , 1,4-butanesultone, ethylene sulfite, lithium difluorobisoxalatophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, succinonitrile, adiponitrile, succinic anhydride, tris(trimethylsilyl) borate, trisphosphate (trimethylsilyl), methylenemethane disulfonate, ethylene glycol bis(propionitrile) ether, 1,3,6-hexanetricarbonitrile, Tripropargyl Phosphate, fluorobenzene or 1,1,2,3- Containing any one type or a combination of at least two types of tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, for example, a combination of propylene sulfate, 1,3-propane sultone, vinylene carbonate, and vinylethylene carbonate. Or it may be a combination of fluoroethylene carbonate, propene sultone and methylenemethane disulfonate.

Preferably, the mass percent content of the film-forming additive in the nonaqueous electrolyte of the lithium ion battery is 0.01 to 20.00%, for example, 0.01%, 1.00%, 5.00%. %, 10.00%, 15.00% or 20.00%, but is not limited to the listed values, other unlisted values within the numerical range apply as well. .

Preferably, the lithium salt includes any one or a combination of at least two of lithium hexafluorophosphate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium bisfluorosulfonylimide, or lithium bistrifluoromethanesulfonylimide, For example, a combination of lithium hexafluorophosphate, lithium perchlorate, lithium trifluoromethanesulfonate and lithium bisfluorosulfonylimide, or a combination of lithium bistrifluoromethanesulfonylimide, lithium hexafluorophosphate and lithium perchlorate. However, it is not limited to the listed types; other non-mentioned types within the scope of lithium salts apply as well.

Preferably, the mass percentage of the lithium salt content in the nonaqueous electrolyte of the lithium ion battery is 2.0 to 25.0%, for example, 2.0%, 5.0%, 8.0%, It may be 10.0%, 15.0%, 20.0% or 25.0%, but it is not limited to the listed values, and other values within the numerical range that are not listed may be used as well. Applicable.

Preferably, the nonaqueous solvent is ethylene glycol diethyl ether, methyl propionate, methyl acetate, propyl propionate, methyl butyrate, ethyl butyrate, propyl acetate, butyl butyrate, acetonitrile, methylpropyl carbonate, ethyl propionate, γ-butyrolactone, Any one or a combination of at least two of sulfolane, dimethyl sulfoxide, tetrahydrofuran, propylene carbonate, ethyl acetate, diethyl carbonate, methyl ethyl carbonate, dimethyl carbonate, or ethylene carbonate, such as ethylene glycol diethyl ether, methyl propionate, It may be a combination of methyl acetate and propyl propionate or a combination of methyl butyrate, ethyl butyrate and propyl acetate, but is not limited to the types listed, but also other types not listed within the scope of non-aqueous solvents. The same applies.

Preferably, the mass percent content of the nonaqueous solvent in the nonaqueous electrolyte of the lithium ion battery is 40.00 to 97.97%, for example, 40.00%, 45.00%, 50.00%. , 55.00%, 60.00%, 70.00%, 80.00%, 95.00% or 97.97%, but is not limited to the numerical values listed and within the range of numerical values. Other values not listed also apply.

In a second aspect, the invention provides a lithium ion battery comprising the non-aqueous electrolyte of the lithium ion battery according to the first aspect.

Preferably, the lithium ion battery further includes a battery case and a battery cell, and the battery cell and the nonaqueous electrolyte of the lithium ion battery are sealed within the battery case.

Preferably, the battery cell includes a positive electrode, a negative electrode, and a separator or solid electrolyte layer provided between the positive electrode and the negative electrode.

Preferably, the material of the positive electrode is an active material capable of intercalating and deintercalating lithium, and the material of the negative electrode is a metal, an alloy, or an active material capable of intercalating and deintercalating lithium. possible metal oxides.

Preferably, the active material capable of intercalating and deintercalating lithium is _LiNix Co _y Mn _z L _(1-x-y-z) O ₂ , LiCo _x' L _(1-x') O ₂ , LiNi _x'' At least one of L'_y' Mn _(2-x''-y') O ₄ or Li _z' MPO ₄ , provided that L is Al, Sr, Mg, Ti, Ca, Zr, Zn, Si or At least one type of Fe, 0≦x≦1, 0≦y≦1, 0≦z≦1, 0<x+y+z≦1, 0<x'≦1, 0.3<x''≦0.6 , 0.01≦y'≦0.2, L' is at least one of Co, Al, Sr, Mg, Ti, Ca, Zr, Zn, Si, or Fe, and 0.5≦z'≦1, M is at least one of Fe, Mn, and Co; for example, the active material capable of intercalating and deintercalating lithium is LiCoO ₂ , LiNi _0.8 Co _0.1 Mn _0.1 O ₂ , LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , LiNi _0.6 Co _0.2 Mn _0.2 O ₂ , LiNi _0.4 Al _0.1 Mn _1.5 O ₄ , LiNi _0.4 Mg _0.1 Mn _{1 .5} O ₄ , Li _0.5 MnPO ₄ or LiFePO ₄ but not limited to the listed types, other types not listed within the range of active materials capable of intercalating and deintercalating lithium. The same applies.

Preferably, the material of the negative electrode is crystalline carbon, lithium metal, LiMnO ₂ , LiAl, Li ₃ Sb, Li ₃ Cd, LiZn, Li ₃ Bi, Li ₄ Si, Li _4.4 Pb, Li _4.4 Sn, At least one of LiC ₆ , Li ₃ FeN ₂ , Li _2.6 CoN _0.4 , Li _2.6 CuN _0.4 or Li ₄ Ti ₅ O ₁₂ , for example, crystalline carbon, lithium metal, crystalline It may be a combination of carbon and LiMnO ₂ or a combination of Li _4.4 Pb and Li _4.4 Sn, but is not limited to the listed types and may also be other types not listed within the range of negative electrode materials. The same applies.

Compared with the conventional technology, the present invention has the following beneficial effects.
(1) The present invention uses an alkenylsiloxane compound with a cyclic structure to form a dense SEI film on the surfaces of the positive and negative electrode materials, and other additives also participate in the interfacial film formation process. By increasing the density and stability, it becomes less likely to be destroyed under high-temperature conditions, while reducing the amount of active lithium ions consumed and securing the capacity of lithium-ion batteries.
(2) The nonaqueous electrolyte according to the present invention contains an additive of an alkenylsiloxane compound, and is used in combination with one or more of lithium difluorophosphate, vinylene carbonate, and lithium difluoro(oxalato)borate. , improve the ion conduction performance and ion transport speed of the SEI membrane, reduce the impedance of the battery, and reduce the internal polarization of the battery and the formation of lithium dendrites, thereby reducing the increase in the internal impedance of the battery due to the consumption of electrolyte. Not only can the problem of gas generation be improved, but also the volumetric expansion of the battery can be suppressed.
(3) The -Si-O- bond of the cyclic alkenylsiloxane compound added in the present invention can complex the metal ions eluted from the positive electrode, reducing the influence of metal ions on the catalytic reaction of the electrolyte. In addition, Si atoms very easily absorb fluorine ions, and can also suppress hydrolysis of fluorine-containing lithium salts.

This is the capacity retention rate and recovery rate of the lithium ion batteries according to Example 1 and Comparative Examples 1 to 4 after being stored at a high temperature of 60° C. for 30 days. This is the volume increase rate of the lithium ion batteries according to Example 1 and Comparative Examples 1 to 4 after storage at a high temperature of 60° C. for 30 days. This is the capacity retention rate of the lithium ion batteries according to Example 1 and Comparative Examples 1 to 4 after 200 cycles at a high temperature of 45°C.

Hereinafter, the technical solution of the present invention will be further explained with reference to drawings and specific embodiments. Those skilled in the art should understand that the following examples are only for understanding the invention and should not be considered as a specific limitation to the invention.

Example 1
This example provides a nonaqueous electrolyte for a lithium ion battery, and the lithium ion nonaqueous electrolyte has a content of 13.5% by mass, assuming the total mass of the nonaqueous electrolyte as 100%. Lithium hexafluorophosphate, 21.0% ethylene carbonate, 7.0% diethyl carbonate and 42.0% Methyl vinyl carbonate non-aqueous solvent, 2.50% T01 alkenyl siloxane compound ( (purchased from Shanghai TCI Chemical Industry Development Co., Ltd.), 10.00% vinylene carbonate (purchased from Jiangsu Huasheng Material Technology Group Co., Ltd.) and 5.00% ethylene sulfate (Shijiazhuang Shengtai Chemical Co., Ltd.) Contains additives (purchased from a company).

The method for preparing the non-aqueous electrolyte for the lithium ion battery is as follows.
The electrolyte solution is prepared in the glove box, the nitrogen content in the glove box is 99.999%, the actual oxygen content in the glove box is <2 ppm, and the water content is <0.1 ppm. The total mass of the non-aqueous electrolyte is taken as 100%, and the battery-grade organic solvent with a mass percentage of 21.0% ethylene carbonate, 7.0% diethyl carbonate, and 42.0% methyl vinyl carbonate is uniformly added. After mixing, a sufficiently dried lithium hexafluorophosphate having a mass percent content of 13.5% is added to the above nonaqueous solvent, and a T01 alkenylsiloxane compound having a mass percent content of 2.50% is added. Furthermore, vinylene carbonate having a mass percentage of 10.00% and ethylene sulfate having a content of 5.00% were added to prepare a non-aqueous electrolyte for a lithium ion battery.

The method for preparing a lithium ion battery is as follows.
Preparation of positive electrode: LiNi _0.8 Co _0.1 Mn _0.1 O ₂ powder, polyvinylidene fluoride (PVDF) as an adhesive, and acetylene black as a conductive agent in a weight ratio of 97.5:1.5:1.5. N-methylpyrrolidone (NMP) was added, and the mixed system was stirred using a vacuum stirrer until it became a positive electrode slurry with uniform fluidity, and the positive electrode slurry was evenly applied to a 15 μm thick aluminum foil. Then, the coated positive electrode slurry was uniformly coated on an aluminum foil with a thickness of 15 μm, and the coated aluminum foil was baked in an oven with 5 different temperature gradients, and then dried in an oven at 120 ° C. for 8 hours. A desired positive electrode piece was obtained by rolling and slitting.

Preparation of negative electrode: negative electrode material of graphite with mass ratio of 95.7 wt%, conductive agent of conductive carbon black (SP) with mass ratio of 1 wt%, dispersion of sodium carboxymethyl cellulose (CMC) with mass ratio of 1.3 wt% A negative electrode slurry was prepared using a wet process using a styrene-butadiene rubber (SBR) adhesive with a mass ratio of 2 wt%, and the negative electrode slurry was uniformly applied to a 15 μm thick copper foil. After baking in an oven with different temperature gradients, it was dried in an oven at 85° C. for 5 hours, and then rolled and slit to obtain a desired graphite negative electrode piece.

Preparation of separator: Polypropylene with a thickness of 7 to 9 mm was used as a separator.

Preparation of lithium ion battery: Roll up the positive electrode piece, separator, and negative electrode piece prepared above to obtain a bare battery cell in which no liquid has been injected, and place the bare battery cell in the outer packaging aluminum foil, and perform the above prepared procedure. The electrolytic solution is injected into a dry bare battery cell, and through processes such as vacuum packaging, standing, chemical formation, shaping, and sorting, the desired lithium ion battery is obtained, and the discharge voltage range is 3.0 to 4.2V. It was set to

Example 2
This example provides a nonaqueous electrolyte for a lithium ion battery, and the lithium ion nonaqueous electrolyte has a content of 2.0% by mass, assuming the total mass of the nonaqueous electrolyte as 100%. Lithium hexafluorophosphate, 12.0% ethylene carbonate, 4.0% diethyl carbonate and 24.0% methyl vinyl carbonate non-aqueous solvent, 0.01% T03 alkenyl siloxane compound (Shanghai TCI Chemical Industrial Development Co., Ltd.), 0.01% vinylene carbonate (purchased from Jiangsu Huasheng Materials Technology Group Co., Ltd.), and 0.01% lithium difluorophosphate (purchased from Jiangsu Guotai Chaowei New Materials Co., Ltd.). Contains additives.

The method for preparing the non-aqueous electrolyte for the lithium ion battery is as follows.
The electrolyte solution is prepared in the glove box, the nitrogen content in the glove box is 99.999%, the actual oxygen content in the glove box is <2 ppm, and the water content is <0.1 ppm. The total mass of the non-aqueous electrolyte is taken as 100%, and the battery-grade organic solvents with a mass percentage of 12.0% ethylene carbonate, 4.0% diethyl carbonate, and 24.0% methyl vinyl carbonate are uniformly added. After mixing, sufficiently dried lithium hexafluorophosphate having a content of 2.0% by mass is added to the above non-aqueous solvent, and a T03 alkenylsiloxane compound having a content of 0.01% by mass is added. Furthermore, vinylene carbonate having a mass percent content of 0.01% and lithium difluorophosphate were added to prepare a non-aqueous electrolyte for a lithium ion battery.

The method for preparing a lithium ion battery is as follows.
Preparation of positive electrode: LiNi _0.8 Co _0.1 Mn _0.1 O ₂ powder, polyvinylidene fluoride (PVDF) as an adhesive, and acetylene black as a conductive agent in a weight ratio of 97.5:1.5:1.5. N-methylpyrrolidone (NMP) was added, and the mixed system was stirred using a vacuum stirrer until it became a positive electrode slurry with uniform fluidity, and the positive electrode slurry was evenly applied to a 15 μm thick aluminum foil. Then, the coated positive electrode slurry was uniformly coated on an aluminum foil with a thickness of 15 μm, and the coated aluminum foil was baked in an oven with 5 different temperature gradients, and then dried in an oven at 120 ° C. for 8 hours. A desired positive electrode piece was obtained by rolling and slitting.

Preparation of negative electrode: negative electrode material of graphite with mass ratio of 95.7 wt%, conductive agent of conductive carbon black (SP) with mass ratio of 1 wt%, dispersion of sodium carboxymethyl cellulose (CMC) with mass ratio of 1.3 wt% A negative electrode slurry was prepared using a wet process using a styrene-butadiene rubber (SBR) adhesive with a mass ratio of 2 wt%, and the negative electrode slurry was uniformly applied to a 15 μm thick copper foil. After baking in an oven with different temperature gradients, it was dried in an oven at 85° C. for 5 hours, and then rolled and slit to obtain a desired graphite negative electrode piece.

Preparation of separator: Polypropylene with a thickness of 7 to 9 mm was used as a separator.

Preparation of lithium ion battery: Roll up the positive electrode piece, separator, and negative electrode piece prepared above to obtain a bare battery cell in which no liquid has been injected, and place the bare battery cell in the outer packaging aluminum foil, and perform the above prepared procedure. The electrolytic solution is injected into a dry bare battery cell, and through processes such as vacuum packaging, standing, chemical formation, shaping, and sorting, the desired lithium ion battery is obtained, and the discharge voltage range is 3.0 to 4.2V. It was set to

Example 3
This example provides a nonaqueous electrolyte for a lithium ion battery, and the lithium ion nonaqueous electrolyte has a content mass percentage of 25.0%, with the total mass of the nonaqueous electrolyte being 100%. Lithium hexafluorophosphate, 28.5% ethylene carbonate, 9.5% diethyl carbonate and 57.0% methyl vinyl carbonate non-aqueous solvent, 5.00% T05 alkenyl siloxane compound (Shanghai TCI Chemical Industrial Development Co., Ltd.), 20.00% vinylene carbonate (purchased from Jiangsu Huasheng Materials Technology Group Co., Ltd.) and 10.00% lithium difluoro(oxalato)borate (Jiangsu Huasheng Materials Technology Group Co., Ltd.) Contains additives (purchased from a company).

The method for preparing the non-aqueous electrolyte for the lithium ion battery is as follows.
The electrolyte solution is prepared in the glove box, the nitrogen content in the glove box is 99.999%, the actual oxygen content in the glove box is <2 ppm, and the water content is <0.1 ppm. The total mass of the non-aqueous electrolyte is taken as 100%, and the battery-grade organic solvents have a mass percentage of 28.5% ethylene carbonate, 9.5% diethyl carbonate, and 57.0% methyl vinyl carbonate. After mixing, a sufficiently dried lithium hexafluorophosphate having a mass percent content of 25.0% is added to the above nonaqueous solvent, and a T05 alkenylsiloxane compound having a mass percent content of 5.00% is added. , 20.00% by weight of vinylene carbonate and 10.00% of lithium difluoro(oxalato)borate were added to prepare a non-aqueous electrolyte for a lithium ion battery.

The method for preparing a lithium ion battery is as follows.
Preparation of positive electrode: LiNi _0.8 Co _0.1 Mn _0.1 O ₂ powder, polyvinylidene fluoride (PVDF) as an adhesive, and acetylene black as a conductive agent in a weight ratio of 97.5:1.5:1.5. N-methylpyrrolidone (NMP) was added, and the mixed system was stirred using a vacuum stirrer until it became a positive electrode slurry with uniform fluidity, and the positive electrode slurry was evenly applied to a 15 μm thick aluminum foil. Then, the coated positive electrode slurry was uniformly coated on an aluminum foil with a thickness of 15 μm, and the coated aluminum foil was baked in an oven with 5 different temperature gradients, and then dried in an oven at 120 ° C. for 8 hours. A desired positive electrode piece was obtained by rolling and slitting.

Preparation of negative electrode: negative electrode material of graphite with mass ratio of 95.7 wt%, conductive agent of conductive carbon black (SP) with mass ratio of 1 wt%, dispersion of sodium carboxymethyl cellulose (CMC) with mass ratio of 1.3 wt% A negative electrode slurry was prepared using a wet process using a styrene-butadiene rubber (SBR) adhesive with a mass ratio of 2 wt%, and the negative electrode slurry was uniformly applied to a 15 μm thick copper foil. After baking in an oven with different temperature gradients, it was dried in an oven at 85° C. for 5 hours, and then rolled and slit to obtain a desired graphite negative electrode piece.

Preparation of separator: Polypropylene with a thickness of 7 to 9 mm was used as a separator.

Preparation of lithium ion battery: Roll up the positive electrode piece, separator, and negative electrode piece prepared above to obtain a bare battery cell in which no liquid has been injected, and place the bare battery cell in the outer packaging aluminum foil, and perform the above prepared procedure. The electrolytic solution is injected into a dry bare battery cell, and through processes such as vacuum packaging, standing, chemical formation, shaping, and sorting, the desired lithium ion battery is obtained, and the discharge voltage range is 3.0 to 4.2V. It was set to

Example 4
This example provides a nonaqueous electrolyte for a lithium ion battery, and the lithium ion nonaqueous electrolyte has a content of 12.5% by mass, assuming the total mass of the nonaqueous electrolyte as 100%. Lithium hexafluorophosphate, 21.0% ethylene carbonate, 7.0% diethyl carbonate and 42.0% methyl vinyl carbonate non-aqueous solvent, 0.01% T02 alkenyl siloxane compound (Shanghai Macklin Biochemical Technology Co., Ltd. 1.00% vinylene carbonate (purchased from Jiangsu Huasheng Materials Technology Group Co., Ltd.) and 1.00% lithium difluorophosphate (purchased from Jiangsu Guotai Chaowei New Materials Co., Ltd.). Contains additives.

The method for preparing the non-aqueous electrolyte for the lithium ion battery is as follows.
The electrolyte solution is prepared in the glove box, the nitrogen content in the glove box is 99.999%, the actual oxygen content in the glove box is <2 ppm, and the water content is <0.1 ppm. The total mass of the non-aqueous electrolyte is taken as 100%, and the battery-grade organic solvent with a mass percentage of 21.0% ethylene carbonate, 7.0% diethyl carbonate, and 42.0% methyl vinyl carbonate is uniformly added. After mixing, sufficiently dried lithium hexafluorophosphate having a content of 12.5% by mass is added to the above non-aqueous solvent, and a T02 alkenylsiloxane compound having a content of 0.01% by mass is added. Then, vinylene carbonate having a mass percentage of 1.00% and lithium difluorophosphate having a content of 1.00% were added to prepare a non-aqueous electrolyte for a lithium ion battery.

The method for preparing a lithium ion battery is as follows.
Preparation of positive electrode: LiNi _0.8 Co _0.1 Mn _0.1 O ₂ powder, polyvinylidene fluoride (PVDF) as an adhesive, and acetylene black as a conductive agent in a weight ratio of 97.5:1.5:1.5. N-methylpyrrolidone (NMP) was added, and the mixed system was stirred using a vacuum stirrer until it became a positive electrode slurry with uniform fluidity, and the positive electrode slurry was evenly applied to a 15 μm thick aluminum foil. Then, the coated positive electrode slurry was uniformly coated on an aluminum foil with a thickness of 15 μm, and the coated aluminum foil was baked in an oven with 5 different temperature gradients, and then dried in an oven at 120 ° C. for 8 hours. A desired positive electrode piece was obtained by rolling and slitting.

Preparation of negative electrode: negative electrode material of graphite with mass ratio of 95.7 wt%, conductive agent of conductive carbon black (SP) with mass ratio of 1 wt%, dispersion of sodium carboxymethyl cellulose (CMC) with mass ratio of 1.3 wt% A negative electrode slurry was prepared using a wet process using a styrene-butadiene rubber (SBR) adhesive with a mass ratio of 2 wt%, and the negative electrode slurry was uniformly applied to a 15 μm thick copper foil. After baking in an oven with different temperature gradients, it was dried in an oven at 85° C. for 5 hours, and then rolled and slit to obtain a desired graphite negative electrode piece.

Preparation of separator: Polypropylene with a thickness of 7 to 9 mm was used as a separator.

Preparation of lithium ion battery: Roll up the positive electrode piece, separator, and negative electrode piece prepared above to obtain a bare battery cell in which no liquid has been injected, and place the bare battery cell in the outer packaging aluminum foil, and perform the above prepared procedure. The electrolytic solution is injected into a dry bare battery cell, and through processes such as vacuum packaging, standing, chemical formation, shaping, and sorting, the desired lithium ion battery is obtained, and the discharge voltage range is 3.0 to 4.2V. It was set to

Example 5
This example provides a nonaqueous electrolyte for a lithium ion battery, and the lithium ion nonaqueous electrolyte has a content of 12.5% by mass, assuming the total mass of the nonaqueous electrolyte as 100%. Lithium hexafluorophosphate, 21.0% ethylene carbonate, 7.0% diethyl carbonate and 42.0% methyl vinyl carbonate non-aqueous solvent, 3.00% T05 alkenyl siloxane compound (Shanghai TCI Chemical Industrial Development Co., Ltd.), 1.00% vinylene carbonate (purchased from Jiangsu Huasheng Materials Technology Group Co., Ltd.) and 0.01% lithium difluoro(oxalato)borate (Jiangsu Huasheng Materials Technology Group Co., Ltd.) Contains additives (purchased from a company).

The method for preparing the non-aqueous electrolyte for the lithium ion battery is as follows.
The electrolyte solution is prepared in the glove box, the nitrogen content in the glove box is 99.999%, the actual oxygen content in the glove box is <2 ppm, and the water content is <0.1 ppm. The total mass of the non-aqueous electrolyte is taken as 100%, and the battery-grade organic solvent with a mass percentage of 21.0% ethylene carbonate, 7.0% diethyl carbonate, and 42.0% methyl vinyl carbonate is uniformly added. After mixing, sufficiently dried lithium hexafluorophosphate having a mass percent content of 12.5% is added to the above nonaqueous solvent, and a T05 alkenylsiloxane compound having a mass percent content of 3.00% is added. Furthermore, vinylene carbonate having a mass percent content of 1.00% and lithium difluoro(oxalato)borate of 0.01% were added to prepare a non-aqueous electrolyte for a lithium ion battery.

The method for preparing a lithium ion battery is as follows.
Preparation of positive electrode: LiNi _0.8 Co _0.1 Mn _0.1 O ₂ powder, polyvinylidene fluoride (PVDF) as an adhesive, and acetylene black as a conductive agent in a weight ratio of 97.5:1.5:1.5. N-methylpyrrolidone (NMP) was added, and the mixed system was stirred using a vacuum stirrer until it became a positive electrode slurry with uniform fluidity, and the positive electrode slurry was evenly applied to a 15 μm thick aluminum foil. Then, the coated positive electrode slurry was uniformly coated on an aluminum foil with a thickness of 15 μm, and the coated aluminum foil was baked in an oven with 5 different temperature gradients, and then dried in an oven at 120 ° C. for 8 hours. A desired positive electrode piece was obtained by rolling and slitting.

Preparation of negative electrode: negative electrode material of graphite with mass ratio of 95.7 wt%, conductive agent of conductive carbon black (SP) with mass ratio of 1 wt%, dispersion of sodium carboxymethyl cellulose (CMC) with mass ratio of 1.3 wt% A negative electrode slurry was prepared using a wet process using a styrene-butadiene rubber (SBR) adhesive with a mass ratio of 2 wt%, and the negative electrode slurry was uniformly applied to a 15 μm thick copper foil. After baking in an oven with different temperature gradients, it was dried in an oven at 85° C. for 5 hours, and then rolled and slit to obtain a desired graphite negative electrode piece.

Preparation of separator: Polypropylene with a thickness of 7 to 9 mm was used as a separator.

Preparation of lithium ion battery: Roll up the positive electrode piece, separator, and negative electrode piece prepared above to obtain a bare battery cell in which no liquid has been injected, and place the bare battery cell in the outer packaging aluminum foil, and perform the above prepared procedure. The electrolytic solution is injected into a dry bare battery cell, and through processes such as vacuum packaging, standing, chemical formation, shaping, and sorting, the desired lithium ion battery is obtained, and the discharge voltage range is 3.0 to 4.2V. It was set to

Example 6
This example provides a nonaqueous electrolyte for a lithium ion battery, and the lithium ion nonaqueous electrolyte has a content of 12.5% by mass, assuming the total mass of the nonaqueous electrolyte as 100%. Lithium hexafluorophosphate, 21.0% ethylene carbonate, 7.0% diethyl carbonate and 42.0% methyl vinyl carbonate non-aqueous solvent, 1.00% T03 alkenyl siloxane compound (Shanghai TCI Chemical Industrial Development Co., Ltd.), 1.00% vinylene carbonate (purchased from Jiangsu Huasheng Materials Technology Group Co., Ltd.), and 1.00% lithium difluorophosphate (purchased from Jiangsu Guotai Chaowei New Materials Co., Ltd.). Contains additives.

The method for preparing the non-aqueous electrolyte for the lithium ion battery is as follows.
The electrolyte solution is prepared in the glove box, the nitrogen content in the glove box is 99.999%, the actual oxygen content in the glove box is <2 ppm, and the water content is <0.1 ppm. The total mass of the non-aqueous electrolyte is taken as 100%, and the battery-grade organic solvent with a mass percentage of 21.0% ethylene carbonate, 7.0% diethyl carbonate, and 42.0% methyl vinyl carbonate is uniformly added. After mixing, sufficiently dried lithium hexafluorophosphate having a mass percent content of 12.5% is added to the above nonaqueous solvent, and a T03 alkenylsiloxane compound having a mass percent content of 1.00% is added. Then, vinylene carbonate having a mass percentage of 1.00% and lithium difluorophosphate having a content of 1.00% were added to prepare a non-aqueous electrolyte for a lithium ion battery.

The method for preparing a lithium ion battery is as follows.
Preparation of positive electrode: LiNi _0.8 Co _0.1 Mn _0.1 O ₂ powder, polyvinylidene fluoride (PVDF) as an adhesive, and acetylene black as a conductive agent in a weight ratio of 97.5:1.5:1.5. N-methylpyrrolidone (NMP) was added, and the mixed system was stirred using a vacuum stirrer until it became a positive electrode slurry with uniform fluidity, and the positive electrode slurry was evenly applied to a 15 μm thick aluminum foil. Then, the coated positive electrode slurry was uniformly coated on an aluminum foil with a thickness of 15 μm, and the coated aluminum foil was baked in an oven with 5 different temperature gradients, and then dried in an oven at 120 ° C. for 8 hours. A desired positive electrode piece was obtained by rolling and slitting.

Preparation of negative electrode: negative electrode material of graphite with mass ratio of 95.7 wt%, conductive agent of conductive carbon black (SP) with mass ratio of 1 wt%, dispersion of sodium carboxymethyl cellulose (CMC) with mass ratio of 1.3 wt% A negative electrode slurry was prepared using a wet process using a styrene-butadiene rubber (SBR) adhesive with a mass ratio of 2 wt%, and the negative electrode slurry was uniformly applied to a 15 μm thick copper foil. After baking in an oven with different temperature gradients, it was dried in an oven at 85° C. for 5 hours, and then rolled and slit to obtain a desired graphite negative electrode piece.

Preparation of separator: Polypropylene with a thickness of 7 to 9 mm was used as a separator.

Preparation of lithium ion battery: Roll up the positive electrode piece, separator, and negative electrode piece prepared above to obtain a bare battery cell in which no liquid has been injected, and place the bare battery cell in the outer packaging aluminum foil, and perform the above prepared procedure. The electrolytic solution is injected into a dry bare battery cell, and through processes such as vacuum packaging, standing, chemical formation, shaping, and sorting, the desired lithium ion battery is obtained, and the discharge voltage range is 3.0 to 4.2V. It was set to

Example 7
This example provides a nonaqueous electrolyte for a lithium ion battery, and the lithium ion nonaqueous electrolyte has a content of 12.5% by mass, assuming the total mass of the nonaqueous electrolyte as 100%. Lithium hexafluorophosphate, 21.0% ethylene carbonate, 7.0% diethyl carbonate and 42.0% methyl vinyl carbonate non-aqueous solvent, 4.00% T01 alkenyl siloxane compound (Shanghai TCI Chemical Industrial Development Co., Ltd.), 2.00% fluoroethylene carbonate (purchased from Shaanxi Zhonglan Chemical Technology New Materials Co., Ltd.) and 1.00% lithium difluorophosphate (Jiangsu Guotai Chaowei New Materials Co., Ltd.). Contains additives (purchased from ).

The method for preparing the non-aqueous electrolyte for the lithium ion battery is as follows.
The electrolyte solution is prepared in the glove box, the nitrogen content in the glove box is 99.999%, the actual oxygen content in the glove box is <2 ppm, and the water content is <0.1 ppm. The total mass of the non-aqueous electrolyte is taken as 100%, and the battery-grade organic solvent with a mass percentage of 21.0% ethylene carbonate, 7.0% diethyl carbonate, and 42.0% methyl vinyl carbonate is uniformly added. After mixing, sufficiently dried lithium hexafluorophosphate having a mass percent content of 12.5% is added to the above nonaqueous solvent, and a T01 alkenylsiloxane compound having a mass percent content of 4.00% is added. Further, fluoroethylene carbonate having a mass percent content of 2.00% and lithium difluorophosphate of 1.00% were added to prepare a non-aqueous electrolyte for a lithium ion battery.

The method for preparing a lithium ion battery is as follows.
Preparation of positive electrode: LiNi _0.8 Co _0.1 Mn _0.1 O ₂ powder, polyvinylidene fluoride (PVDF) as an adhesive, and acetylene black as a conductive agent in a weight ratio of 97.5:1.5:1.5. N-methylpyrrolidone (NMP) was added, and the mixed system was stirred using a vacuum stirrer until it became a positive electrode slurry with uniform fluidity, and the positive electrode slurry was evenly applied to a 15 μm thick aluminum foil. Then, the coated positive electrode slurry was uniformly coated on an aluminum foil with a thickness of 15 μm, and the coated aluminum foil was baked in an oven with 5 different temperature gradients, and then dried in an oven at 120 ° C. for 8 hours. A desired positive electrode piece was obtained by rolling and slitting.

Preparation of negative electrode: negative electrode material of graphite with mass ratio of 95.7 wt%, conductive agent of conductive carbon black (SP) with mass ratio of 1 wt%, dispersion of sodium carboxymethyl cellulose (CMC) with mass ratio of 1.3 wt% A negative electrode slurry was prepared using a wet process using a styrene-butadiene rubber (SBR) adhesive with a mass ratio of 2 wt%, and the negative electrode slurry was uniformly applied to a 15 μm thick copper foil. After baking in an oven with different temperature gradients, it was dried in an oven at 85° C. for 5 hours, and then rolled and slit to obtain a desired graphite negative electrode piece.

Preparation of separator: Polypropylene with a thickness of 7 to 9 mm was used as a separator.

Preparation of lithium ion battery: Roll up the positive electrode piece, separator, and negative electrode piece prepared above to obtain a bare battery cell in which no liquid has been injected, and place the bare battery cell in the outer packaging aluminum foil, and perform the above prepared procedure. The electrolytic solution is injected into a dry bare battery cell, and the desired lithium ion battery is obtained through processes such as vacuum packaging, standing, chemical formation, shaping, and sorting, and the discharge voltage range is set to 3.0 to 4.2V. Set.

Example 8
The difference between this example and Example 1 is that ethylene sulfate and vinylene carbonate were not added in the process of preparing the non-aqueous electrolyte for the lithium ion battery, and all other aspects were the same as in Example 1.

Example 9
The difference between this comparative example and Example 1 is that in the process of preparing a nonaqueous electrolyte for a lithium ion battery, the total mass of the nonaqueous electrolyte is 100%, and the content of the alkenylsiloxane compound is 10.00% by mass. There are certain things, and everything else is the same as in Example 1.

Comparative example 1
The difference between this comparative example and Example 1 is that no alkenylsiloxane compound was added in the process of preparing the non-aqueous electrolyte for the lithium ion battery, and all other aspects were the same as in Example 1.

Comparative example 2
The difference between this comparative example and Example 1 is that the alkenyl siloxane compound is changed to siloxane compound A (purchased from Shanghai Meryer Chemical Technology Co., Ltd.) having the following structure in the process of preparing the non-aqueous electrolyte for the lithium ion battery. In particular, everything else is the same as in the first embodiment.

Comparative example 3
The difference between this comparative example and Example 1 is that 1,3-propane sultone and vinylene carbonate were added instead of adding an alkenylsiloxane compound and ethylene sulfate in the process of preparing a non-aqueous electrolyte for a lithium ion battery. The total mass of the non-aqueous electrolyte is 100%, the mass percentage of the content of 1,3-propane sultone is 7.50%, the mass percentage of the content of vinylene carbonate is 10.00%, and the other This is also the same as in Example 1.

Comparative example 4
The difference between this comparative example and Example 1 is that 1,3-propane sultone was added instead of adding an alkenylsiloxane compound, ethylene sulfate, and vinylene carbonate in the process of preparing a nonaqueous electrolyte for a lithium ion battery. The mass percentage of the content of 1,3-propane sultone was 17.50%, with the total mass of the non-aqueous electrolyte being 100%, and all other aspects were the same as in Example 1.

Comparative example 5
The difference between this comparative example and Example 1 is that vinylene carbonate was added instead of alkenylsiloxane compounds, ethylene sulfate, and 1,3-propane sultone in the process of preparing a nonaqueous electrolyte for a lithium ion battery. The mass percentage of the vinylene carbonate content was 17.50%, with the total mass of the non-aqueous electrolyte being 100%, and all other aspects were the same as in Example 1.

Comparative example 6
The difference between this comparative example and Example 1 is that alkenyl siloxane compounds, ethylene sulfate, 1,3-propane sultone, and vinylene carbonate were not added during the preparation process of the nonaqueous electrolyte for lithium ion batteries, and the nonaqueous solvent contained Contains a non-aqueous solvent of 25.95% ethylene carbonate, 8.65% diethyl carbonate, and 51.9% methyl vinyl carbonate, and all others are the same as in Example 1.

Test Conditions The lithium ion batteries prepared in Examples 1 to 9 and Comparative Examples 1 to 6 were subjected to high temperature cycle, high temperature storage performance, and ionic conductivity performance tests, respectively, and the test methods were as follows.

(1) High temperature cycle test: The battery was placed in a 45°C environment and the chemically formed battery was tested using LiNi _0.8 Co _0.1 Mn _0.1 O ₂ as the positive electrode material and artificial graphite as the negative electrode material. , the battery was charged to 4.2V at a constant current and voltage of 1C, the cutoff current was 0.02C, and then discharged to 3.0V at a constant current of 1C. After performing charge/discharge cycles in this manner, the capacity retention rate after 200 cycles was calculated, and the cycle performance was evaluated accordingly.
The formula for calculating the capacity retention rate after 200 cycles at 45°C is as follows.
Capacity retention rate at 200th cycle (%) = (discharge capacity at 200th cycle/discharge capacity at 1st cycle) *100%

(2) High temperature storage test: The chemically formed battery was charged to 4.2V at 1C constant current and voltage at 25°C, using LiNi _0.8 Co _0.1 Mn _0.1 O ₂ as the positive electrode material. The negative electrode material is artificial graphite, the cut-off current is 0.02C, and the battery is further discharged at a constant current of 1C to 3.0V, the initial discharge capacity of the battery is measured, and then the cut-off current is 0.02C. The initial thickness of the battery was measured by charging it to 4.2V with a cut-off current of 0.01C, and then storing the battery at 60℃ for 30 days. After measuring, discharge to 3.0V with a constant current of 1C, measure the holding capacity of the battery, then charge to 3.0V with a constant current and constant voltage of 1C, and the cut-off current is 0.02C. After that, the battery was discharged to 3.0V at a constant current of 1C, and the recovery capacity was measured.
The formulas for calculating the capacity retention rate, capacity recovery rate, and volumetric expansion rate are as follows.
Battery capacity retention rate (%) = retention capacity / initial capacity * 100%
Battery capacity recovery rate (%) = recovery capacity / initial capacity * 100%
Battery volume expansion rate (%) = (Volume after 30 days - Initial volume) / Initial volume * 100%

The test results are shown in Table 2.

As can be seen from the data in Tables 1 and 2, the present invention conducted high-temperature cycle and high-temperature storage performance tests on the lithium ion battery prepared in the above example using a non-aqueous electrolyte containing alkenylsiloxane. , FIG. 1 shows the capacity retention rate and recovery rate of the lithium ion batteries according to Example 1 and Comparative Examples 1 to 4 after storage at a high temperature of 60°C for 30 days. It has been shown that the lithium ion battery according to the present invention has a high capacity retention rate and a high capacity recovery rate, and furthermore, the lithium ion battery prepared using the electrolyte of the present invention has a high cycle retention rate and a high storage capacity retention rate and a high capacity recovery rate. Figure 2 shows the volume increase rate of the lithium ion batteries of Example 1 and Comparative Examples 1 to 4 after storage at a high temperature of 60°C for 30 days. The increase in thickness is much smaller than that of the lithium ion batteries of Comparative Examples 1 to 4, further indicating that the use of the electrolyte according to the present invention can slow the volumetric expansion of the battery. Additionally, using alkenylsiloxane-containing compounds in combination with lithium difluorophosphate, vinylene carbonate, and lithium difluoro(oxalato)borate provides better battery performance than using alkenylsiloxane compound additives alone. , and the volume expansion rate of the battery after high-temperature storage is much smaller than that of the comparative example. Therefore, when the electrolyte of the present invention is applied to a lithium-ion battery, it has good high-temperature long-term cycle stability, high-temperature storage stability, and good It has safety performance.

Figure 3 shows the capacity retention rates of the lithium ion batteries of Example 1 and Comparative Examples 1 to 4 after 200 cycles at a high temperature of 45°C. I explained that it was expensive. In Comparative Example 2, even with an additive that contains a cyclic siloxane compound but does not contain double bonds of alkenyl groups, the capacity retention rate after 200 cycles at 45°C is 80% or less, and the capacity retention rate after high-temperature storage at 60°C is 80% or less. The recovery rate and recovery rate are both lower than 90%, indicating that the thickness increase rate is much higher than that of the example, and the effect of the other comparative example without the siloxane compound additive is lower than this comparative example 2. If there is no alkenylsiloxane compound additive in the electrolyte, the impedance of the lithium battery will be large and the lithium ion conductivity will be poor, and transition metal ions in the positive electrode will be eluted due to high temperatures, inducing sustained decomposition of the catalyst solvent. As a result, lithium ions were consumed excessively, causing a decrease in the capacity retention rate and recovery rate of the battery under high-temperature conditions. Moreover, due to the continuous decomposition of the solvent, on the one hand, gas was generated, and on the other hand, the SEI film was continuously repaired, and the SEI film continued to thicken, making the pole pieces thicker, both of which led to an increase in the volume of the battery. .

Although the present invention has explained the non-aqueous electrolyte of the lithium ion battery of the present invention and its use through the above-mentioned Examples, the present invention is not limited to the above-mentioned Examples. The applicant hereby declares that this is not something that can only be implemented. Those skilled in the art will understand that all improvements to the present invention, equivalent substitutions and additions of auxiliary ingredients to each raw material of the product of the present invention, selection of specific forms, etc., all fall within the protection scope and disclosure scope of the present invention. You should understand.

Claims (7)

A lithium ion comprising a lithium salt, a non-aqueous solvent, and an additive, the additive comprising an alkenylsiloxane compound having a cyclic structure represented by formula (1), an impedance reducing additive, and a film-forming additive. A non-aqueous electrolyte for a battery ,
The impedance reducing additive includes any one or a combination of at least two of lithium difluorophosphate, ethylene sulfate, or lithium difluoro(oxalato)borate;
A nonaqueous electrolyte for a lithium ion battery, wherein the content of the impedance reducing additive in the nonaqueous electrolyte for the lithium ion battery has a mass percentage of 0.01 to 10.00%.

(However, the alkenylsiloxane compound having a cyclic structure represented by the above formula (1) is any one of the following compounds.)

Claim 1, wherein the content of the alkenylsiloxane compound having a cyclic structure represented by formula (1) in the non-aqueous electrolyte of the lithium ion battery has a mass percentage of 0.01 to 5.00%. A non-aqueous electrolyte for a lithium ion battery as described in . The nonaqueous electrolyte of the lithium ion battery further includes a film-forming additive, and the film-forming additive includes propylene sulfate, 1,3-propane sultone, vinylene carbonate, vinylethylene carbonate, fluoroethylene carbonate, propene sultone, 1, 4-Butanesultone, ethylene sulfite, lithium difluorobisoxalatophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, succinonitrile, adiponitrile, succinic anhydride, tris(trimethylsilyl) borate, tris(trimethylsilyl) phosphate , methylenemethane disulfonate, ethylene glycol bis(propionitrile) ether, 1,3,6-hexanetricarbonitrile, tripropargyl phosphate, fluorobenzene or 1,1,2,3-tetrafluoroethyl-2,2 , 3,3-tetrafluoropropyl ether or a combination of at least two thereof,
The nonaqueous electrolyte of the lithium ion battery according to claim 1 or 2 , wherein the content of the film-forming additive in the nonaqueous electrolyte of the lithium ion battery is 0.01 to 20.00% by mass. Water electrolyte. The lithium salt includes any one or a combination of at least two of lithium hexafluorophosphate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium bisfluorosulfonylimide, or lithium bistrifluoromethanesulfonylimide,
The lithium ion according to any one of claims 1 to 3 , wherein the content of lithium salt in the nonaqueous electrolyte of the lithium ion battery has a mass percentage of 2.0 to 25.0%. Non-aqueous electrolyte for batteries. The nonaqueous solvents include ethylene glycol diethyl ether, methyl propionate, methyl acetate, propyl propionate, methyl butyrate, ethyl butyrate, propyl acetate, butyl butyrate, acetonitrile, methylpropyl carbonate, ethyl propionate, γ-butyrolactone, sulfolane, and dimethyl. Any one or a combination of two of sulfoxide, tetrahydrofuran, propylene carbonate, ethyl acetate, diethyl carbonate, methyl ethyl carbonate, dimethyl carbonate, or ethylene carbonate, and is a non-aqueous solvent in the non-aqueous electrolyte of the lithium ion battery. The nonaqueous electrolyte for a lithium ion battery according to any one of claims 1 to 4 , wherein the content in mass percent is 40.00 to 97.97%. A lithium ion battery comprising the nonaqueous electrolyte of the lithium ion battery according to any one of claims 1 to 5 . The lithium ion battery further includes a battery case and a battery cell, and the battery cell and the nonaqueous electrolyte of the lithium ion battery are sealed within the battery case,
The battery cell includes a positive electrode, a negative electrode, and a separator or solid electrolyte layer provided between the positive electrode and the negative electrode,
The material of the positive electrode is an active material capable of intercalating and deintercalating lithium, and the material of the negative electrode is a metal or alloy capable of deintercalating lithium or forming an alloy with lithium, or a metal capable of intercalating/deintercalating lithium. is an oxide,
The active materials capable of intercalating and deintercalating lithium include _LiNix Co _y Mn _z L _(1-x-y-z) O ₂ , LiCo _x' L _(1-x') O ₂ , LiNi _x'' L' _{y '} Mn _(2-x''-y') O ₄ or Li _{z '} MPO ₄ , provided that L is at least one of Al, Sr, Mg, Ti, Ca, Zr, Zn, Si or Fe. 1 type, 0≦x≦1, 0≦y≦1, 0≦z≦1, 0<x+y+z≦1, 0<x'≦1, 0.3<x''≦0.6, 0. 01≦y'≦0.2, L' is at least one of Co, Al, Sr, Mg, Ti, Ca, Zr, Zn, Si, or Fe, 0.5≦z'≦1, M is Fe , Mn or Co,
The negative electrode materials include crystalline carbon, lithium metal, LiMnO ₂ , LiAl, Li ₃ Sb, Li ₃ Cd, LiZn, Li ₃ Bi, Li ₄ Si, Li _4.4 Pb, Li _4.4 Sn, LiC ₆ , The lithium ion battery according to claim 6 , characterized in that it is at least one of Li ₃ FeN ₂ , Li _2.6 CoN _0.4 , Li _2.6 CuN _0.4 or Li ₄ Ti ₅ O ₁₂ .

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