CN112242559A - Non-aqueous electrolyte of lithium ion battery and lithium ion battery using same - Google Patents
Non-aqueous electrolyte of lithium ion battery and lithium ion battery using same Download PDFInfo
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- H01M10/00—Secondary cells; Manufacture thereof
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- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
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- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
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Abstract
The invention discloses a non-aqueous electrolyte for a lithium ion battery and the lithium ion battery using the same. The non-aqueous electrolyte for the lithium ion battery comprises a lithium salt, a non-aqueous organic solvent and an additive, wherein the additive comprises a heterocyclic compound shown as a formula (I) or a heterocyclic compound shown as a formula (II), and further comprises fluoroethylene carbonate (FEC), 1, 3-Propane Sultone (PS), Vinylene Carbonate (VC), ethylene carbonate (VEC), ethylene sulfate (DTD) and lithium difluorophosphate (LiPO)2F2) One or more of (a). The non-aqueous electrolyte for the lithium ion battery contains the heterocyclic compound, can effectively prevent the decomposition of the battery electrolyte on the surface of a cathode and the oxidation of the electrolyte under a high-temperature environment, and can be compared with the traditional lithium ion secondary battery without the combined additiveThe service life of the battery is effectively prolonged, and the storage capacity of the battery in a high-temperature environment can be improved.
Description
Technical Field
The invention relates to the field of batteries, in particular to a non-aqueous electrolyte for a lithium ion battery and the lithium ion battery using the non-aqueous electrolyte.
Background
The lithium ion battery consists of a positive electrode, a negative electrode, an electrolyte and a separator. The electrolyte has no electronic conductivity but only ionic conductivity, and its main function is to transfer lithium ions between the anode and cathode. Although basic performances of the lithium ion battery, such as operating voltage, energy density, etc., are determined by the constituent materials of the cathode and the anode, in order to obtain excellent battery performance, the electrolyte must have high ionic conductivity, electrochemical stability and thermal stability, and the electrolyte must maintain electrochemical stability in each corresponding potential region in consideration of the reduction reaction of the anode and the oxidation reaction of the cathode.
In recent years, due to the characteristics of high energy density and easy design, lithium ion batteries have been widely used, especially in the development of energy sources and alternative energy sources for electric vehicles, and medium-and large-sized lithium ion batteries have also been used as energy storage sources for generating electric energy. As the application field of lithium ion batteries is expanded to the electric vehicle field and the electric power storage field, high-voltage electrode active materials are widely used.
However, on the one hand, since the cathode of the lithium ion battery employs a cathode active material of high potential and the anode employs an anode active material of low potential, the potential window of the electrolyte is narrower than that of the active material. The electrolyte is exposed on the surfaces of the cathode and the anode electrodes and is easy to decompose. Meanwhile, when used in an electric vehicle or a power storage device, the lithium ion battery is easily exposed to a high-temperature environment. In addition, the temperature of the battery may also increase due to instantaneous charging and current changes. Therefore, in a high-temperature environment, the service life of the battery is reduced, and the storable energy is also reduced. On the other hand, LiPF, a main salt of a lithium ion battery6Under the action of high temperature or trace water, HF is easily generated by decomposition, an SEI film is damaged, electrode materials are corroded, transition metal ions are released, decomposition of an electrolyte is further promoted, vicious circle is formed, and the performance of the lithium ion battery is deteriorated.
Disclosure of Invention
The present invention is directed to overcome the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a nonaqueous electrolyte solution capable of improving the high-temperature performance and cycle life of a lithium ion battery, which can effectively prevent the oxidation of an electrolyte on the surface of a cathode and the decomposition of the electrolyte solution in a high-temperature environment, and a lithium ion battery using the same.
In order to achieve the object of the present invention, the nonaqueous electrolyte solution for a lithium ion battery according to the present invention includes a lithium salt, a nonaqueous organic solvent, and an additive, wherein the additive includes a heterocyclic compound represented by formula (I):
or a heterocyclic compound comprising the formula (II):
in the formula (I), X1、X2、X3、X4Each independently represents a hydrogen atom, a saturated alkyl group, an unsaturated alkyl group, an alkoxy group, a haloalkyl group, a halogen atom, a cyano group, an isocyanate group, and X1、X2One of them can form a double bond with the C atom to which the two N atoms are attached;
in the formula (II), Y1、Y2And Y3Each independently represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms, an alkoxy group of 1 to 5 carbon atoms, an alkenyl group of 1 to 5 carbon atoms, an alkynyl group of 1 to 5 carbon atoms, a halogen atom; wherein, Y2And Y3One of which may form a double bond with the C atom to which the two N atoms are attached.
Further, the compound represented by the formula (I) is selected from the following compounds:
preferably, the compound represented by the formula (I) is added in an amount of 0.05 to 0.5%, for example, 0.05 to 0.15% by mass of the electrolyte.
Further, the compound represented by the formula (II) is selected from the following compounds:
preferably, the compound represented by the formula (II) is added in an amount of 0.05 to 0.5%, for example, 0.05 to 0.15% by mass of the electrolyte.
Furthermore, the additive also comprises fluoroethylene carbonate (FEC), 1, 3-Propane Sultone (PS), Vinylene Carbonate (VC), ethylene carbonate (VEC), vinyl sulfate (DTD) and lithium difluorophosphate (LiPO)2F2) One or more of; preferably, the mass percentage of the additives in the electrolyte is 0.1-15%.
Further preferably, the additive also comprises fluoroethylene carbonate (FEC), 1, 3-Propane Sultone (PS), Vinylene Carbonate (VC) and lithium difluorophosphate; more preferably, the additive further comprises fluoroethylene carbonate (FEC) accounting for 1% of the mass of the electrolyte, 1, 3-Propane Sultone (PS) accounting for 1.5% of the mass of the electrolyte, Vinylene Carbonate (VC) accounting for 0.5% of the mass of the electrolyte and lithium difluorophosphate accounting for 1% of the mass of the electrolyte.
In the present invention, the lithium salt is selected from LiPF6，LiBF4，LiDFOB，LiBOB，LiDFBOP，LiPO2F2，LiSbF6，LiAsF6，LiCF3S03，Li(CF3S02)3C，Li(CF3S02)2N，Li(FS02)2N，LiC4F9S03，LiClO4，LiAlO2，LiAlCl4One or more of; preferably, the concentration of the lithium salt in the electrolyte is 0.5-2M, for example 1-1.5M, in terms of lithium ions; further preferably, the lithium salt is LiPF6。
In the present invention, the non-aqueous organic solvent is selected from one or more of a carbonate solvent, a carboxylate solvent, an ether solvent, and a fluoro carbonate/carboxylate/ether solvent; preferably, the carbonate solvent is selected from one or more of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC) and ethylpropyl carbonate (EPC), the carbonate solvent is selected from one or more of methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate and delta-decalactone, and the ether solvent is selected from one or more of dibutyl ether, tetraethylene glycol, dimethoxyethane, 2-methyltetrahydrofuran and tetrahydrofuran.
Preferably, the non-aqueous organic solvent comprises Ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and diethyl carbonate (DEC), and the three are mixed in a ratio of 30%, 20% and 50% by mass.
The invention also provides a lithium ion battery, which uses the non-aqueous electrolyte for the lithium ion battery.
Preferably, the preparation method of the lithium ion battery comprises the steps of injecting the nonaqueous electrolyte for the lithium ion battery into a fully dried 4.4V NCM (nickel: cobalt: manganese ═ 5:2: 3)/graphite soft package battery, standing at 45 ℃, forming by a high-temperature clamp, and carrying out secondary sealing.
The electrolyte contains heterocyclic compounds, so that the decomposition of the battery electrolyte on the surface of a cathode and the oxidation of the electrolyte under a high-temperature environment can be effectively prevented, and compared with the traditional lithium ion secondary battery without the combined additive, the non-aqueous electrolyte for the lithium ion battery can effectively prolong the service life of the battery and improve the storage capacity of the battery under the high-temperature environment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. It is to be understood that the following description is only illustrative of the present invention and is not to be construed as limiting the present invention.
The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.
When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.
The indefinite articles "a" and "an" preceding an element or component of the invention are not intended to limit the number requirement (i.e., the number of occurrences) of the element or component. Thus, "a" or "an" should be read to include one or at least one, and the singular form of an element or component also includes the plural unless the number clearly indicates the singular.
Further, the technical features of the embodiments of the present invention may be combined with each other as long as they do not conflict with each other.
Example 1
The non-aqueous electrolyte is prepared by the following method: in a glove box, Ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and diethyl carbonate (DEC) were mixed in a ratio of 30%, 20% and 50% in percentage, and then lithium hexafluorophosphate was added to dissolve them, to prepare an electrolyte solution having a lithium hexafluorophosphate concentration of 1.3M. Then, 0.5% by mass of vinylene carbonate, 1% by mass of fluoroethylene carbonate (FEC), 1.5% by mass of 1, 3-propane sultone, and 1% by mass of lithium difluorophosphate were added to the electrolyte, and 0.01% by mass of the compound (1) was added.
And injecting the prepared nonaqueous electrolyte for the lithium ion battery into a fully dried 4.4V NCM (nickel: cobalt: manganese: 5:2: 3)/graphite soft package battery, standing at 45 ℃, forming by a high-temperature clamp, sealing for the second time and the like, and then testing the battery performance to obtain the lithium ion battery.
Example 2
The preparation method of the positive electrode and the negative electrode of the embodiment 2 is the same as that of the embodiment 1; except that 0.05% of the compound (1) was added to the nonaqueous electrolytic solution in example 2 during the preparation.
Example 3
The preparation method of the positive electrode and the negative electrode of the embodiment 3 is the same as that of the embodiment 1; except that 0.1% of the compound (1) was added to the nonaqueous electrolytic solution in example 3 during the preparation.
Example 4
The preparation method of the positive electrode and the negative electrode of the embodiment 4 is the same as that of the embodiment 1; except that 0.15% of compound (1) was added to the nonaqueous electrolytic solution in example 4 during the preparation.
Example 5
The preparation method of the positive electrode and the negative electrode of the embodiment 5 is the same as that of the embodiment 1; except that 0.2% of compound (1) was added to the nonaqueous electrolytic solution in example 5 during the preparation.
Example 6
The preparation method of the positive electrode and the negative electrode of the embodiment 6 is the same as that of the embodiment 1; except that 0.1% of compound (2) was added to the nonaqueous electrolytic solution in example 6 during the preparation.
Example 7
The preparation method of the positive electrode and the negative electrode of example 7 is the same as that of example 1; except that 0.1% of the compound (3) was added to the nonaqueous electrolytic solution in example 7 during the preparation.
Example 8
The preparation method of the positive electrode and the negative electrode of the embodiment 8 is the same as that of the embodiment 1; except that 0.1% of the compound (4) was added to the nonaqueous electrolytic solution in example 8 during the preparation.
Example 9
The preparation method of the positive electrode and the negative electrode of example 9 is the same as that of example 1; except that 0.1% of compound (5) was added to the nonaqueous electrolytic solution in example 9 during the preparation.
Example 10
The preparation methods of the positive electrode and the negative electrode of example 10 are the same as those of example 1; except that 0.1% of the compound (6) was added to the nonaqueous electrolytic solution in example 10 during the preparation.
Example 11
The preparation methods of the positive electrode and the negative electrode of example 11 are the same as those of example 1; except that 0.1% of the compound (7) was added to the nonaqueous electrolytic solution in example 11 during the preparation.
Example 12
The preparation methods of the positive electrode and the negative electrode of example 12 are the same as those of example 1; except that 0.1% of the compound (8) was added to the nonaqueous electrolytic solution in example 12 during the preparation.
Example 13
The preparation methods of the positive electrode and the negative electrode of example 13 are the same as those of example 1; except that 0.1% of the compound (9) was added to the nonaqueous electrolytic solution in example 13 during the preparation.
Example 14
The preparation methods of the positive electrode and the negative electrode of example 14 are the same as those of example 1; except that 0.1% of the compound (10) was added to the nonaqueous electrolytic solution in example 14 during the preparation.
Example 15
The preparation methods of the positive electrode and the negative electrode of example 15 are the same as those of example 1; except that 0.1% of compound (11) was added to the nonaqueous electrolytic solution in example 15 during the preparation.
Comparative example 1
The non-aqueous electrolyte is prepared by the following method: in a glove box, Ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and diethyl carbonate (DEC) were mixed in a ratio of 30%, 20% and 50% in percentage, and then lithium hexafluorophosphate was added to dissolve them, to prepare an electrolyte solution having a lithium hexafluorophosphate concentration of 1.3M. Then, vinylene carbonate was added to the electrolyte in an amount of 0.5% by mass.
And injecting the prepared nonaqueous electrolyte for the lithium ion battery into a fully dried 4.4V NCM (nickel: cobalt: manganese: 5:2: 3)/graphite soft package battery, standing at 45 ℃, forming by a high-temperature clamp, sealing for the second time and the like, and then testing the battery performance to obtain the lithium ion battery.
Comparative example 2
The non-aqueous electrolyte is prepared by the following method: in a glove box, Ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and diethyl carbonate (DEC) were mixed in a ratio of 30%, 20% and 50% in percentage, and then lithium hexafluorophosphate was added to dissolve them, to prepare an electrolyte solution having a lithium hexafluorophosphate concentration of 1.3M. Then, 0.5% by mass of vinylene carbonate and 1% by mass of fluoroethylene carbonate (FEC) were added to the electrolyte.
And injecting the prepared nonaqueous electrolyte for the lithium ion battery into a fully dried 4.4V NCM (nickel: cobalt: manganese: 5:2: 3)/graphite soft package battery, standing at 45 ℃, forming by a high-temperature clamp, sealing for the second time and the like, and then testing the battery performance to obtain the lithium ion battery.
Comparative example 3
The non-aqueous electrolyte is prepared by the following method: in a glove box, Ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and diethyl carbonate (DEC) were mixed in a ratio of 30%, 20% and 50% in percentage, and then lithium hexafluorophosphate was added to dissolve them, to prepare an electrolyte solution having a lithium hexafluorophosphate concentration of 1.3M. Then, 0.5% by mass of vinylene carbonate, 1% by mass of fluoroethylene carbonate (FEC) and 1.5% by mass of 1, 3-propane sultone were added to the electrolyte.
And injecting the prepared nonaqueous electrolyte for the lithium ion battery into a fully dried 4.4V NCM (nickel: cobalt: manganese: 5:2: 3)/graphite soft package battery, standing at 45 ℃, forming by a high-temperature clamp, sealing for the second time and the like, and then testing the battery performance to obtain the lithium ion battery.
Comparative example 4
The non-aqueous electrolyte is prepared by the following method: in a glove box, Ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and diethyl carbonate (DEC) were mixed in a ratio of 30%, 20% and 50% in percentage, and then lithium hexafluorophosphate was added to dissolve them, to prepare an electrolyte solution having a lithium hexafluorophosphate concentration of 1.3M. Then, 0.5% by mass of vinylene carbonate, 1% by mass of fluoroethylene carbonate (FEC), 1.5% by mass of 1, 3-propane sultone, and 1% by mass of lithium difluorophosphate were added to the electrolyte, and 0.01% by mass of the compound (1) was added.
And injecting the prepared nonaqueous electrolyte for the lithium ion battery into a fully dried 4.4V NCM (nickel: cobalt: manganese: 5:2: 3)/graphite soft package battery, standing at 45 ℃, forming by a high-temperature clamp, sealing for the second time and the like, and then testing the battery performance to obtain the lithium ion battery.
TABLE 1 electrolyte formulations for the examples and comparative examples
Lithium ion battery performance testing
1. Normal temperature cycle performance
Under the condition of normal temperature (25 ℃), the lithium ion battery is charged to 4.4V under the constant current and the constant voltage of 0.5C, and then is discharged to 3.0V under the constant current of 0.5C. After 400 cycles of charge and discharge, the capacity retention rate after the 400 th cycle was calculated as:
2. high temperature cycle performance
The lithium ion battery is charged to 4.4V at a constant current and a constant voltage of 0.5 ℃ under the condition of high temperature (45 ℃), and then discharged to 3.0V under the condition of a constant current of 0.5 ℃. After 300 cycles of charge and discharge, the capacity retention rate after the 300 th cycle was calculated as:
3. high temperature storage Properties
Under the condition of normal temperature (25 ℃), the lithium ion battery is charged and discharged once at 0.5C/0.5C (the discharge capacity is recorded as DC)0) Then charging the battery to 4.4V under the condition of constant current and constant voltage of 0.5C; the lithium ion battery is placed in a high-temperature box with the temperature of 55 ℃ for 1 week, and after being taken out, 0.5C discharge (the discharge capacity is recorded as DC) is carried out under the condition of normal temperature1) (ii) a Then, charge and discharge were carried out at ordinary temperature at 0.5C/0.5C (discharge capacity was designated as DC)2) Calculating the capacity retention rate and the capacity recovery rate of the lithium ion battery by using the following formulas:
table 2 results of cell performance test for each comparative example and example
From the data in the table, it can be seen that when vinylene carbonate (comparative example 1) is added alone and used for a high-potential 4.4V-523/AG soft-package battery, normal-temperature cycle, high-temperature cycle performance and 60 ℃ storage performance are poor, because the negative electrode of VC mainly forms an organic polymer film, the VC is not resistant to high temperature and is easily decomposed at high temperature, while the VC can form a film on the surface of the positive electrode, but has poor thermal stability, and meanwhile, the VC itself has a low oxidation potential and is easily oxidized and decomposed at high potential, and meanwhile, the transition metal ions can also play a role in catalytic decomposition.
On the one hand, VC and FEC cooperate to participate in the formation of an SEI film, the SEI formed at the negative electrode contains an organic polymer film, inorganic LiF and the like, the stability of the film is improved, but the FEC presents the characteristic of instability under the high-temperature environment, and is easy to defluorinate to form HF, so that the phenomena of deterioration of the high-temperature cycle performance and poor high-temperature storage performance of the battery are caused. The introduction of 1, 3-propane sultone in comparative example 3 further improves the normal temperature and high temperature cycle performance of the battery, and the corresponding high temperature storage performance is further increased, while the introduction of lithium difluorophosphate in comparative example 4 mainly improves the normal temperature and high temperature cycle performance, and the improvement of the high temperature storage performance is not obvious.
In the embodiments 1-5, the compound (1) accounting for 0.01%, 0.05%, 0.1%, 0.15% and 0.2% of the electrolyte is added, and as shown in the data in the table above, after the additive is introduced into the electrolyte, the high-temperature storage performance of the obtained lithium ion battery is obviously improved; in the case of the normal temperature cycle, when the additive is added in an amount of 0.1% or less, the cycle performance tends to be improved with the increase in the amount of the additive, and when the additive is added in an amount of 0.15% or more, the cycle performance is rather deteriorated, so that it can be seen that the optimum amount of the additive is 0.05 to 0.15% (e.g., 0.1%), the effect of improving the high temperature is not obtained when the additive is too small, and the increase in the internal resistance of the battery may be caused when the additive is too large.
Compared with the influence of the additive on the battery cycle at normal temperature, the influence of excessive ketone groups (heterocyclic compounds shown in a formula (II)) on the high-temperature cycle is relatively similar, and the introduction of excessive ketone groups is unfavorable for the high temperature; comparing the high-temperature cycle and storage performance of nitrile group, fluorine and methyl functional group compounds contained in the purine rings, the high-temperature performance of the compounds introduced into the purine rings is relatively poorer than that of the compounds introduced into the nitrile group, fluorine atom and oxygen-containing group, and the high-temperature performance is probably an electron-donating group with the methyl group, so that the side reaction is increased.
Because the heterocyclic compounds introduced by the invention can form a solid electrolyte interface on the surface of the cathode active material of the battery, the direct contact between the electrolyte and the cathode active material can be prevented. And simultaneously can prevent the electrolyte from losing electrons to the cathode and being oxidized at high temperature and high pressure, and the life span and high-temperature storage performance of the lithium secondary battery can be improved.
It will be understood by those skilled in the art that the foregoing is only exemplary of the present invention, and is not intended to limit the invention, which is intended to cover any variations, equivalents, or improvements therein, which fall within the spirit and scope of the invention.
Claims (10)
1. A nonaqueous electrolyte for a lithium ion battery, comprising a lithium salt, a nonaqueous organic solvent and an additive, wherein the additive contains a heterocyclic compound represented by the formula (I):
or a heterocyclic compound comprising the formula (II):
in the formula (I), X1、X2、X3、X4Each independently represents a hydrogen atom, a saturated alkyl group, an unsaturated alkyl group, an alkoxy group, a haloalkyl group, a halogen atom, a cyano group, an isocyanate group, and X1、X2One of them can form a double bond with the C atom to which the two N atoms are attached;
in the formula (I)I) In, Y1、Y2And Y3Each independently represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms, an alkoxy group of 1 to 5 carbon atoms, an alkenyl group of 1 to 5 carbon atoms, an alkynyl group of 1 to 5 carbon atoms, a halogen atom; wherein, Y2And Y3One of which may form a double bond with the C atom to which the two N atoms are attached.
2. The nonaqueous electrolyte solution for a lithium ion battery according to claim 1, wherein the compound represented by the formula (I) is selected from the following compounds:
preferably, the compound represented by the formula (I) is added in an amount of 0.05 to 0.5%, for example, 0.05 to 0.15% by mass of the electrolyte.
3. The nonaqueous electrolyte solution for a lithium ion battery according to claim 1, wherein the compound represented by the formula (II) is selected from the following compounds:
preferably, the compound represented by the formula (II) is added in an amount of 0.05 to 0.5%, for example, 0.05 to 0.15% by mass of the electrolyte.
4. The nonaqueous electrolyte for a lithium ion battery according to claim 1, wherein the additive contains one or more of fluoroethylene carbonate, 1, 3-propane sultone, vinylene carbonate, ethylene carbonate, ethylene sulfate, and lithium difluorophosphate; preferably, the mass percentage of the additive in the electrolyte is 0.1-15%.
5. The nonaqueous electrolyte for a lithium ion battery according to claim 4, wherein the additive comprises fluoroethylene carbonate, 1, 3-propane sultone, vinylene carbonate and lithium difluorophosphate; more preferably, the additive also comprises fluoroethylene carbonate accounting for 1 percent of the mass of the electrolyte, 1, 3-propane sultone accounting for 1.5 percent of the mass of the electrolyte, vinylene carbonate accounting for 0.5 percent of the mass of the electrolyte and lithium difluorophosphate accounting for 1 percent of the mass of the electrolyte.
6. The nonaqueous electrolyte solution for lithium ion batteries according to claim 1, wherein the lithium salt is selected from LiPF6，LiBF4，LiDFOB，LiBOB，LiDFBOP，LiPO2F2，LiSbF6，LiAsF6，LiCF3S03，Li(CF3S02)3C，Li(CF3S02)2N，Li(FS02)2N，LiC4F9S03，LiClO4，LiAlO2，LiAlCl4One or more of; preferably, the concentration of the lithium salt in the electrolyte is 0.5-2M, for example 1-1.5M, in terms of lithium ions; further preferably, the lithium salt is LiPF6。
7. The nonaqueous electrolyte solution for a lithium ion battery according to claim 1, wherein the nonaqueous organic solvent is one or more selected from a carbonate-based solvent, a carboxylate-based solvent, an ether-based solvent, and a fluoro carbonate/carboxylate/ether-based solvent; preferably, the carbonate solvent is selected from one or more of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate and ethyl propyl carbonate, the carboxylic ester solvent is selected from one or more of methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate and delta-decalactone, and the ether solvent is selected from one or more of dibutyl ether, tetraethylene glycol, dimethoxyethane, 2-methyltetrahydrofuran and tetrahydrofuran.
8. The nonaqueous electrolyte solution for a lithium ion battery according to claim 1 or 7, wherein the nonaqueous organic solvent contains ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate, and the three are mixed in a ratio of 30 mass%, 20 mass%, and 50 mass%.
9. A lithium ion battery comprising the nonaqueous electrolyte for lithium ion batteries according to any one of claims 1 to 8.
10. The lithium ion battery according to claim 9, wherein the method for producing a lithium ion battery comprises injecting the nonaqueous electrolytic solution for a lithium ion battery according to any one of claims 1 to 8 into a fully dried 4.4V nickel: cobalt: the manganese-manganese.
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