Non-aqueous electrolyte and lithium ion battery thereof

Abstract

The invention provides a non-aqueous electrolyte and a lithium ion battery thereof. The non-aqueous electrolyte comprises a lithium salt, a non-aqueous organic solvent and an additive, wherein the additive comprises a compound A as shown in a formula I and a compound B as shown in a formula II. Wherein R1, R2, R3 and R4 are respectively and independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl and substituted or unsubstituted C2-C12 alkynyl, n is a natural number from 1 to 5, and M is alkali metal. The non-aqueous electrolyte provided by the invention contains two additives, namely the compound A and the compound B, and through the synergistic effect of the two additives, the increase of high-temperature storage internal resistance can be reduced, and the high-temperature storage performance of the lithium ion battery can be improved. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a non-aqueous electrolyte and a lithium ion battery containing the non-aqueous electrolyte. Background Art

[0002] In lithium-ion batteries, film-forming additives such as VC, PS, DTD, etc. undergo redox reactions before carbonate solvents such as EC, forming a solid electrolyte film with a thickness of about 100nm on the surface of the positive or negative electrode, which contains inorganic components such as Li2O, LiF, Li2CO3 and organic components such as LiOCO2R, LiOSO2R. Its function is to prevent the contact between the electrolyte and the positive and negative electrodes during the charging and discharging of lithium-ion batteries, and reduce the side reactions between the electrolyte and the positive and negative electrodes. Especially under extreme conditions such as high and low temperatures, film-forming additives play an irreplaceable role. However, the SEI film formed by current film-forming additives is not dense and has uneven thickness, resulting in poor high-temperature performance and an adverse effect on the high-temperature calendar life of the battery.

[0003] Therefore, a non-aqueous electrolyte and a lithium ion battery thereof are urgently needed to solve the above problems. Summary of the invention

[0004] The object of the present invention is to provide a non-aqueous electrolyte and a lithium ion battery comprising the non-aqueous electrolyte. The non-aqueous electrolyte comprises a compound A having a sulfonimide structure and a compound B having an amphoteric salt structure. The non-aqueous electrolyte comprising the additive compound is applied to a lithium ion battery to reduce the growth of the internal resistance during high-temperature storage and improve the high-temperature storage performance of the lithium ion battery.

[0005] To achieve the above object, the present invention provides a non-aqueous electrolyte, including a lithium salt, a non-aqueous organic solvent and an additive, wherein the additive includes a compound A shown in Formula 1 and a compound B shown in Formula 2:

[0006]

[0007] Among them, R1, R2, R3, and R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, n is a natural number of 1 to 5, and M is an alkali metal.

[0008] Compared with the prior art, the non-aqueous electrolyte of the present invention includes a lithium salt, a non-aqueous organic solvent and an additive, wherein the additive includes a compound A containing a cyclic sulfonyl imide salt structure as shown in formula 1 and a compound B having an amphoteric salt structure as shown in formula 2, and the non-aqueous electrolyte containing the additive compound is applied to a lithium ion battery, wherein compound A has a large anion structure and has a weaker binding ability with alkali metal ions, so that it can be solvated and desolvated faster in the electrolyte, thereby improving the electrolyte solvation structure, and the addition of compound B optimizes the SEI component. At the same time, since the amphoteric sites in the structure of compound B can adjust the solvation structure of the original lithium ions, the dissociated "free" lithium ions are evenly distributed at the molecular level, reducing lithium precipitation, so the combination of compound A and compound B can reduce the growth of high-temperature storage impedance and improve the high-temperature storage performance of lithium ion batteries.

[0009] Preferably, R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, R3 and R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, n is a natural number of 1 to 3, and M is selected from Na or Li.

[0010] Preferably, compound A is selected from at least one of compound 1 to compound 4:

[0011]

[0012] Preferably, compound A accounts for 0.05% to 5% of the total mass of the lithium salt, the non-aqueous organic solvent and the additive.

[0013] Preferably, compound B is selected from at least one of compounds 5 to 7:

[0014]

[0015] Preferably, compound B accounts for 0.01% to 1% of the total mass of the lithium salt, the non-aqueous organic solvent and the additive.

[0016] Preferably, the lithium salt is selected from at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium bistrifluoromethanesulfonyl imide, lithium bisoxalatoborate, lithium difluorophosphate, lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium lower aliphatic carboxylate, lithium difluorobisoxalatephosphate, lithium bisfluorosulfonyl imide, lithium chloroborane and lithium tetraphenylborate.

[0017] Preferably, the non-aqueous organic solvent is selected from at least one of γ-butyrolactone, γ-valerolactone, δ-valerolactone, methyl acetate, ethyl acetate, ethyl propionate, butyl acetate, propyl propionate, butyl propionate, ethylene carbonate, propylene carbonate, butylene carbonate, methyl pentyl carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, propylene carbonate, 1,3-dioxolane, 1,4-dioxane, crown ether, tetrahydrofuran, 2-methyltetrahydrofuran, 2-trifluoromethyltetrahydrofuran, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

[0018] Preferably, the additive further includes an auxiliary agent, and the auxiliary agent is selected from at least one of fluoroethylene carbonate, ethylene sulfite, 1,3-propane sultone, 1,3-propene sultone, 1,4-butane sultone, ethylene sulfate, and succinic anhydride.

[0019] On the other hand, the present invention provides a lithium-ion battery, which includes a positive electrode material and a negative electrode material, and further includes the aforementioned non-aqueous electrolyte. Detailed Embodiments

[0020] The lithium-ion battery of the present invention includes a positive electrode, a negative electrode, and a non-aqueous electrolyte. Among them, the positive electrode includes a positive electrode material, and the positive electrode material is selected from at least one of nickel cobalt manganese oxide, nickel cobalt aluminum oxide, and lithium cobalt oxide. Specifically, the positive electrode material can be nickel cobalt manganese oxide, and its chemical formula can be LiNi8Co1Mn1O2, LiNi5Co2Mn3O2, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 or LiNi x Co y Mn z M (1xyz) O2; for another example, the positive electrode material can be nickel cobalt aluminum oxide, and its chemical formula can be LiNi x Co y Al z N (1xyz) O2, where M and N are each independently selected from at least one of Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V, and Ti, 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z ≤ 1; for another example, the positive electrode material is lithium cobalt oxide, and its chemical formula is LiCoO2. As an example, the positive electrode material of the present invention is LiNi8Co1Mn1O2. The negative electrode includes a negative electrode material, and the negative electrode material is selected from at least one of artificial graphite, natural graphite, lithium titanate, silicon-carbon composite material, and silicon monoxide. As an example, the negative electrode material of the present invention is artificial graphite. The non-aqueous electrolyte includes a lithium salt, a non-aqueous organic solvent, and an additive.

[0021] The lithium salt is selected from at least one of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium bisoxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium bisoxalate borate (LiBOB), lithium difluorooxalate borate (LiDFOB), lithium lower aliphatic carboxylate, lithium difluorobisoxalate phosphate (LiDFBP), lithium bisfluorosulfonyl imide (LiFSI), lithium chloroborane and lithium tetraphenylborate. As an example, the lithium salt is lithium hexafluorophosphate (LiPF6), but is not limited thereto. Furthermore, the lithium salt is a mixture of lithium hexafluorophosphate (LiPF6) and lithium bisoxalate borate (LiBOB), but is not limited thereto.

[0022] The lithium salt accounts for 5-25% of the total mass of the non-aqueous organic solvent, the lithium salt and the additive. Further, the lithium salt accounts for 8-20% of the total mass of the non-aqueous organic solvent, the lithium salt and the additive. More preferably, the lithium salt accounts for 10-15% of the total mass of the non-aqueous organic solvent, the lithium salt and the additive. By way of example, the lithium salt accounts for 5%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 20%, 25% of the total mass of the non-aqueous organic solvent, the lithium salt and the additive, but is not limited to the listed values, and other values ​​not listed within the numerical range are equally applicable.

[0023] The non-aqueous organic solvent is selected from the group consisting of γ-butyrolactone (GBL), γ-valerolactone (GVL), δ-valerolactone (DVL), methyl acetate (MA), ethyl acetate (EA), ethyl propionate (EP), butyl acetate (BAC), propyl propionate (PP), butyl propionate (PRB), ethylene carbonate (EC), propylene carbonate (PCA), butylene carbonate (BC), methyl amyl carbonate (MPC), vinylene carbonate (VEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl carbonate At least one of propylene carbonate (MPC), propylene carbonate (PC), 1,3-dioxolane (DOL), 1,4-dioxolane (DX), crown ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH3-THF), 2-trifluoromethyltetrahydrofuran (2-CF3-THF), dimethoxymethane (DMM), diethoxymethane (DEM), ethoxymethoxymethane (DCE), ethylene glycol di-n-propyl ether (EDP), ethylene glycol di-n-butyl ether (EDB) and diethylene glycol dimethyl ether (DEGME).

[0024] The non-aqueous organic solvent accounts for 65-90% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive. Preferably, the non-aqueous organic solvent accounts for 75-89% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive. More preferably, the non-aqueous organic solvent accounts for 78-88% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive. As an example, the non-aqueous organic solvent accounts for 65%, 70%, 80%, 85%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 90% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] The additive of the present invention comprises compound A shown in formula 1 and compound B shown in formula 2:

[0026]

[0027] Among them, R1, R2, R3, and R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, n is a natural number of 1 to 5, and M is an alkali metal.

[0028] Furthermore, R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, R3 and R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, n is a natural number of 1 to 3, and M is selected from Na or Li.

[0029] As an example, the compound A of the present invention is selected from at least one of compounds 1 to 4:

[0030]

[0031] Specifically, compounds 1 to 4 can be prepared according to the following synthetic routes:

[0032]

[0033]

[0034] The compound A of the present invention accounts for 0.05% to 5% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive. Preferably, the compound A accounts for 0.1% to 4% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive, and more preferably, the compound A accounts for 0.5 to 2% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive. As an example, the compound A accounts for 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0035] As an example, the compound B of the present invention is selected from at least one of compounds 5 to 7:

[0036]

[0037] The compound B of the present invention accounts for 0.01% to 1% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive. Preferably, the compound B accounts for 0.1% to 0.8% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive, and more preferably, the compound B accounts for 0.3% to 0.6% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive. As an example, the compound B accounts for 0.01%, 0.02%, 0.04%, 0.06%, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0% of the sum of the mass of the lithium salt, the non-aqueous organic solvent and the additive, but is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0038] The additive of the present invention also includes an auxiliary agent, which is selected from at least one of fluoroethylene carbonate (FEC), vinyl sulfite (ES), 1,3-propane sultone (PS), 1,3-propene sultone (PST), 1,4-butane sultone (1,4-BS), vinyl sulfate (DTD) and succinic anhydride (SA). The auxiliary agent accounts for 0.05-5% of the total mass of the lithium salt, the non-aqueous organic solvent and the additive. Preferably, the auxiliary agent accounts for 0.1-4% of the total mass of the lithium salt, the non-aqueous organic solvent and the additive, and more preferably, the auxiliary agent accounts for 0.5-3% of the total mass of the lithium salt, the non-aqueous organic solvent and the additive. As an example, the additive accounts for 0.05%, 0.1%, 0.2%, 0.4%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, or 5% of the sum of the mass of the lithium salt, the non-aqueous organic solvent, and the additive, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] In order to better illustrate the purpose, technical scheme and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of the present invention and should not be used as a limitation of the present invention.

[0040] Example 1

[0041] (1) Preparation of non-aqueous electrolyte

[0042] In a glove box filled with argon (O2 <1ppm, H2O <1ppm), ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were mixed in a weight ratio of EC:EMC:DEC=3:5:2 to prepare 85g of a non-aqueous organic solvent, and then 0.5g of compound 1 and 0.01g of compound 5 were added. After dissolving and stirring thoroughly, 14.5g of lithium hexafluorophosphate was added and mixed evenly to obtain a non-aqueous electrolyte.

[0043] (2) Preparation of positive electrode

[0044] NCM811, adhesive PVDF and conductive agent SuperP were mixed evenly in a mass ratio of 95:1:4 to prepare a positive electrode slurry for a lithium-ion battery with a certain viscosity. The mixed slurry was coated on both sides of an aluminum foil, and then dried and rolled to obtain a positive electrode sheet.

[0045] (3) Preparation of negative electrode

[0046] Artificial graphite, conductive agent SuperP, thickener CMC, and adhesive SBR (styrene-butadiene rubber latex) are made into slurry in a mass ratio of 95:1.5:1.0:2.5, mixed evenly, coated on both sides of copper foil with the mixed slurry, and then dried and rolled to obtain a negative electrode sheet.

[0047] (4) Preparation of lithium-ion batteries

[0048] The positive electrode, the separator and the negative electrode are wound into a soft-pack battery cell, which is packaged with a polymer aluminum-plastic film and filled with the prepared lithium-ion battery non-aqueous electrolyte. After the processes of formation and capacity separation, a lithium-ion battery with a capacity of 1000 mAh is manufactured.

[0049] The formulations of the non-aqueous electrolytes of Examples 1 to 21 and Comparative Examples 1 to 4 are shown in Table 1, wherein the steps of preparing the electrolytes and preparing the batteries of Examples 2 to 21 and Comparative Examples 1 to 4 are the same as those of Example 1.

[0050] Table 1 Formulas of non-aqueous electrolytes in various embodiments and comparative examples

[0051]

[0052]

[0053]

[0054] The lithium ion batteries prepared in Examples 1 to 21 and Comparative Examples 1 to 4 were subjected to high temperature storage test and internal resistance growth rate test respectively. The specific test conditions are as follows. The performance test results are shown in Table 2.

[0055] Lithium-ion battery high temperature storage capacity retention performance test

[0056] At a constant temperature of 25°C, the lithium-ion battery is charged at a constant current of 1C to a voltage of 4.2V, and then charged at a constant voltage of 4.2V to a current of 0.05C, and then discharged at a constant current of 1C to a voltage of 3.0V, and the first cycle discharge capacity of the battery is recorded as C0. The lithium-ion battery is then placed in a constant temperature box at 60°C and left to stand for 30 minutes to allow the lithium-ion battery to reach a constant temperature. After being stored at 60°C for 15 days, it is discharged to 3V at a constant current and constant voltage of 1C / 1C at a constant temperature of 25°C, and the discharge capacity is recorded as C1. The lithium-ion battery is then charged at a constant current of 1C to a voltage of 4.2V at a constant temperature of 25°C again, and then charged to a current of 0.05C at a constant voltage of 4.2V. After continuing to store at 60°C for 15 days, it is discharged to 3V at a constant current and constant voltage of 1C / 1C at a constant temperature of 25°C, and the discharge capacity is recorded as C2. The capacity retention rate of the lithium-ion battery stored for 15 days and 30 days is calculated using the following formulas.

[0057] Storage for 15 days Capacity retention rate = (C1 / C0) · 100%

[0058] Storage 30 days capacity retention rate = (C2 / C0) · 100%

[0059] Lithium-ion battery internal resistance growth rate test

[0060] Internal resistance growth rate after 30 days of high-temperature storage: At 25°C, the battery after 30 days of storage was charged at 0.5C constant current and constant voltage at room temperature to a cut-off voltage of 4.2V, and then discharged at constant current and constant voltage until the capacity dropped to 50% SOC, and the internal resistance of the battery was tested.

[0061] The resistance growth rate of the battery during 30 days of high-temperature storage = (battery internal resistance after 30 days of storage - battery internal resistance of the first full charge) / battery internal resistance of the first full charge × 100%.

[0062] Table 2 Lithium-ion battery performance test results

[0063]

[0064]

[0065] Specifically, as shown in Table 2, the performance data of Examples 1 to 21 are compared with the performance data of Comparative Examples 1 to 4. It can be seen that the lithium ion batteries of Examples 1 to 21 have good high temperature cycle performance. This may be because the additives of the present invention include compound A with a sulfonimide structure and compound B with an amphoteric salt structure. Compound A and compound B have amphoteric structures in the lithium ion battery system, which can adjust the molecular size of Li + Solvation structure, convenient for Li + The shuttling and desolvation between the positive and negative electrodes kinetically reduce the polarization effect and reduce the negative impact of its polarization effect on the growth of DCR of lithium-ion batteries under high temperature conditions.

[0066] Further comparison of Examples 1 to 12 shows that when Compound 1 is used in combination with Compound 7, its performance is better. This may be because Compound 1 has only one methyl substituent compared to Compound 2, and Compounds 1 to 4 are cyclic lithium salt structures. The greater the anion electron cloud density, the stronger the ability to bind to lithium ions. The desolvation energy of lithium ions in the process of embedding and de-embedding of positive and negative electrodes is higher, and its electron-donating ability contributes to the sulfonimide group electrons, making Compound 1 have better binding to Li than Compound 2. + The desolvation ability of Li + Rapidly shuttling between the positive and negative electrodes is more conducive to improving its high-temperature storage performance; and compared with the same series of structures, compound 7 has the ability to oligomerize and polymerize with other additives in the electrochemical system of lithium-ion batteries due to the presence of double bond substituents, which improves the quality of SEI film formation, making the SEI film denser and more uniform in composition. Therefore, compound 1 and compound 7 are used together, and the two are oligomerized or even polymerized through double bond cross-linking in the electrochemical system of lithium batteries to form a three-dimensional cross-linked framework SEI film. The electrolyte film based on this polymer adjusts the negative charge arrangement on the surface of the negative electrode to make the SEI film thickness uniform. At the same time, the polymer electrolyte film can adjust the original lithium ion solvation structure due to the amphoteric sites of compound 7, so that the dissociated "free" lithium ions are evenly distributed at the molecular level, reducing lithium precipitation, reducing the growth of high-temperature storage impedance, and improving the high-temperature storage performance of lithium-ion batteries.

[0067] It can be seen from Example 3 and Examples 19 to 21 that by further adding auxiliary agents on the basis of the additives, the high-temperature storage performance is better and the internal resistance growth rate is lower.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A non-aqueous electrolyte comprising a lithium salt, a non-aqueous organic solvent and an additive, characterized in that: The additive includes compound A shown in formula 1 and compound B shown in formula 2: Among them, R1, R2, R3, and R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, substituted or unsubstituted C2-C12 alkynyl, n is a natural number of 1 to 5, and M is an alkali metal.

2. The non-aqueous electrolyte according to claim 1, characterized in that R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, R3 and R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C2-C12 alkenyl, n is a natural number of 1 to 3, and M is selected from Na or Li.

3. The non-aqueous electrolyte according to claim 1, characterized in that The compound A is selected from at least one of compound 1 to compound 4:

4. The non-aqueous electrolyte according to claim 1, characterized in that The compound A accounts for 0.05% to 5% of the total mass of the lithium salt, the non-aqueous organic solvent and the additive.

5. The non-aqueous electrolyte according to claim 1, characterized in that The compound B is selected from at least one of compounds 5 to 7:

6. The non-aqueous electrolyte according to claim 1, characterized in that The compound B accounts for 0.01% to 1% of the total mass of the lithium salt, the non-aqueous organic solvent and the additive.

7. The non-aqueous electrolyte according to claim 1, characterized in that The lithium salt is selected from at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium bistrifluoromethanesulfonyl imide, lithium bisoxalatoborate, lithium difluorophosphate, lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium lower aliphatic carboxylate, lithium difluorobisoxalatophosphate, lithium bisfluorosulfonyl imide, lithium chloroborane and lithium tetraphenylborate.

8. The non-aqueous electrolyte according to claim 1, characterized in that The non-aqueous organic solvent is selected from at least one of γ-butyrolactone, γ-valerolactone, δ-valerolactone, methyl acetate, ethyl acetate, ethyl propionate, butyl acetate, propyl propionate, butyl propionate, ethylene carbonate, propylene carbonate, butylene carbonate, methyl pentyl carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, propylene carbonate, 1,3-dioxolane, 1,4-dioxane, crown ether, tetrahydrofuran, 2-methyltetrahydrofuran, 2-trifluoromethyltetrahydrofuran, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether and diethylene glycol dimethyl ether.

9. The non-aqueous electrolyte according to claim 1, characterized in that The additive further comprises an auxiliary agent, and the auxiliary agent is selected from at least one of fluoroethylene carbonate, vinyl sulfite, 1,3-propane sultone, 1,3-propylene sultone, 1,4-butane sultone, vinyl sulfate and succinic anhydride.

10. A lithium-ion battery comprising a positive electrode material and a negative electrode material, characterized in that: It also includes the non-aqueous electrolyte according to any one of claims 1 to 9.

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