Non-aqueous electrolyte and lithium ion battery

Abstract

The invention discloses a non-aqueous electrolyte and a lithium ion battery, the non-aqueous electrolyte comprises a lithium salt, a non-aqueous organic solvent and an additive, the additive comprises a compound A as shown in a formula 1 and a compound B as shown in a formula 2: # imgabs0 #, R1 is selected from hydrogen and C1-C6 alkyl, R2 is selected from hydrogen or halogen, R3-R4 are independently selected from C1-C6 alkyl and C2-C6 alkynyl, and R5-R6 are independently selected from C1-C6 alkyl and C2-C6 alkenyl. Through the synergistic effect of the compound A and the compound B, the non-aqueous electrolyte forms an SEI film with higher stability in the charging and discharging period of the lithium ion battery, the oxidation stability of the electrolyte is enhanced, the electrolyte is prevented from being oxidized and decomposed by high-catalytic-activity Ni < 2 + > dissolved out of the positive electrode, the degradation of the high-nickel positive electrode is inhibited, and the service life of the lithium ion battery is prolonged. And meanwhile, lithium precipitation is inhibited by optimizing a lithium ion solvation structure and improving the conductivity, so that the improvement of the lithium ion battery in the aspects of high-temperature cycling stability and storage performance is finally realized, and a high-temperature lithium precipitation phenomenon is avoided.

Description

Technical Field

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

[0002] With the continuous growth of the demand for high-performance and high-safety energy storage devices in modern society, lithium-ion batteries, as one of the most popular current energy storage solutions, are facing the challenges of improving their performance and safety. Although lithium-ion batteries have made remarkable progress in terms of energy density, cycle life, etc., there are still several problems in the existing technologies that limit their further application and development.

[0003] First of all, the electrolyte system used in traditional lithium-ion batteries is prone to thermal decomposition in the face of high-temperature environments. This not only leads to a significant decline in battery performance but also may trigger a series of safety hazards, such as gas release, shell expansion, and even serious accidents such as explosion; especially in the case of using high-nickel cathode materials, due to the high catalytic activity of Ni 2+ ions, they can accelerate the oxidation decomposition process of the electrolyte, further exacerbating the rate of battery deterioration and shortening the service life of the battery. In addition, as the number of battery charge and discharge cycles increases, especially in a fast-charging environment, lithium ions tend to deposit unevenly on the surface of the negative electrode to form lithium dendrites. These slender lithium metal protrusions not only reduce the effective capacity of the battery but, more dangerously, they may penetrate the separator, causing internal short circuits, thereby triggering the risks of electrolyte leakage, fire, and even explosion.

[0004] Therefore, there is an urgent need for a non-aqueous electrolyte and a lithium-ion battery to solve the deficiencies of the existing technologies. Summary of the Invention

[0005] In view of the above problems, the purpose of the present invention is to provide a non-aqueous electrolyte and a lithium-ion battery, and the lithium-ion battery has good high-temperature cycle stability, high-temperature storage performance and no lithium precipitation at high temperature.

[0006] To achieve the above purpose, the present invention provides a non-aqueous electrolyte, which includes a lithium salt, a non-aqueous organic solvent, and an additive. The additive includes compound A shown in formula 1 and compound B shown in formula 2:

[0007] Wherein, R1 is selected from hydrogen, C1-C6 alkyl, R2 is selected from hydrogen or halogen, R3-R4 are each independently selected from C1-C6 alkyl, C2-C6 alkynyl, and R5-R6 are each independently selected from C1-C6 alkyl, C2-C6 alkenyl.

[0008] Compared with the prior art, in the present invention, a compound A containing a carboxylic ester fluorine structure and a compound B containing a siloxane structure are introduced as additives into a non-aqueous electrolyte. Among them, the compound A reduces the HOMO energy level of the electrolyte through its fluorine-containing group, greatly improving the antioxidant stability. At the same time, the fluorine atoms in the compound A form an inorganic SEI layer rich in LiF during the charge and discharge process to enhance the electrode interface stability, and the low-viscosity characteristic of the carboxylic ester structure in the compound A also significantly improves the conductivity of the non-aqueous electrolyte. The compound B endows the electrolyte with excellent thermal stability and chemical stability by utilizing the high bond energy (452 kJ / mol) of the Si-O bond. The siloxane structure in the compound B can spontaneously form an anion-rich solvation structure at a low salt concentration due to its unique weak solvation property. This not only improves the redox compatibility with the cathode and anode, but also reduces the electrolyte cost and the corrosion of the current collector, effectively inhibiting the growth of lithium dendrites. Therefore, through the synergistic effect of the compound A and the compound B, the present invention enables the non-aqueous electrolyte to form a more stable SEI film during the charge and discharge of the lithium-ion battery, enhances the oxidation stability of the electrolyte, and avoids the high catalytic activity of Ni 2+ oxidizing and decomposing the electrolyte, inhibiting the deterioration of the high-nickel cathode. At the same time, by optimizing the lithium-ion solvation structure and increasing the conductivity, the lithium precipitation at high temperature is inhibited. Finally, the improvement of the lithium-ion battery in terms of high-temperature cycle stability and storage performance is achieved, and there is no phenomenon of lithium precipitation at high temperature.

[0009] Further, in the present invention, R1 is selected from hydrogen, C1-C3 alkyl groups, R2 is selected from hydrogen or fluorine, R3-R4 are each independently selected from C1-C3 alkyl groups, C2-C3 alkynyl groups, and R5-R6 are each independently selected from C1-C3 alkyl groups, C2-C3 alkenyl groups. Specifically, the C1-C3 alkyl group can be, but is not limited to, methyl (-CH3), ethyl (-C2H5), n-propyl (-CH2CH2CH3), and isopropyl (-CH(CH3)2). The C2-C3 alkynyl group can be, but is not limited to, ethynyl (-C≡CH), propynyl (-CH2C≡CH), and 1-propynyl (-C≡C-CH3). The C2-C3 alkenyl group can be, but is not limited to, vinyl (-CH=CH2), 1-propenyl (-CH=CH-CH3), 2-propenyl (-CH2-CH=CH2), and isopropenyl (-C(CH3)=CH2).

[0010] Further, the compound A in the present invention is selected from at least one of compound 1 to compound 3: .

[0011] Among them, the CAS number of compound 1 is 123349-99-5; the CAS number of compound 2 is 406-05-3; the CAS number of compound 3 is 56135-00-3.

[0012] Further, Compound B of the present invention is selected from at least one of Compound 4 to Compound 6: .

[0013] Among them, the CAS number of Compound 4 is 18187-24-1; the CAS number of Compound 5 is 175884-78-3; the CAS number of Compound 6 is 123257-85-2.

[0014] Further, the mass percentage of Compound A of the present invention in the non-aqueous electrolyte is 0.05-5%; the mass percentage of Compound B in the non-aqueous electrolyte is 0.05-5%. Specifically, the mass percentage of Compound A in the non-aqueous electrolyte can be, but is not limited to, 0.05%, 0.1%, 0.5%, 0.8%, 1.2%, 1.6%, 2%, 2.6%, 3%, 3.6%, 4.2%, 4.5%, 5%. Specifically, the mass percentage of Compound B in the non-aqueous electrolyte can be, but is not limited to, 0.05%, 0.1%, 0.5%, 0.8%, 1.2%, 1.6%, 2%, 2.6%, 3%, 3.6%, 4.2%, 4.5%, 5%. Preferably, the mass percentage of Compound A in the non-aqueous electrolyte is 0.05-2%; the mass percentage of Compound B in the non-aqueous electrolyte is 0.05-2%.

[0015] Further, the lithium salt of the present invention is selected from at least one of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(oxalato)borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium lower aliphatic carboxylate, lithium difluorodioxalate phosphate (LiDFBP), lithium bis(fluorosulfonyl)imide (LiFSI), lithium chloroborane, and lithium tetraphenylborate.

[0016] Further, the mass percentage of the lithium salt of the present invention in the non-aqueous electrolyte is 5-25%, and further, the mass percentage of the lithium salt in the non-aqueous electrolyte is 8-20%. Preferably, the mass percentage of the lithium salt in the non-aqueous electrolyte is 10-15%. Specifically, the mass percentage of the lithium salt in the non-aqueous electrolyte can be, but is not limited to, 5%, 8%, 12%, 16%, 18%, 22%, 25%.

[0017] Furthermore, the non-aqueous organic solvent of the present invention is selected from at least one 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), propyl butyrate (PRB), ethylene carbonate (EC), propylene carbonate (PCA), butylene carbonate (BC), methyl pentyl carbonate (MPC), vinylene carbonate (VEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), propylene carbonate (PC), 1,3-dioxolane (DOL), 1,4-dioxane (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).

[0018] Furthermore, the mass percentage of the non-aqueous organic solvent of the present invention in the non-aqueous electrolyte is 65-90%. Preferably, the mass percentage of the non-aqueous organic solvent of the present invention in the non-aqueous electrolyte is 75-89%. Specifically, the mass percentage of the non-aqueous organic solvent in the non-aqueous electrolyte can be, but is not limited to, 65%, 70%, 80%, 85%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 90%.

[0019] Furthermore, the present invention also includes an additive, which is selected from at least one of ethylene sulfite (ES), 1,3-propane sultone (PS), 1,3-propene sultone (PST), 1,4-butane sultone (1,4-BS), dimethyl sulfate ethylene ester (DTD), and succinic anhydride (SA).

[0020] Furthermore, the mass percentage of the additive of the present invention in the non-aqueous electrolyte is 0.05-5%. Preferably, the mass percentage of the additive in the non-aqueous electrolyte is 0.1-4%, and more preferably, the mass percentage of the additive in the non-aqueous electrolyte is 0.5-3%.

[0021] Correspondingly, the present invention also provides a lithium-ion battery, which includes a positive electrode, a negative electrode, and also includes the non-aqueous electrolyte mentioned above. This lithium-ion battery has good high-temperature cycle stability, high-temperature storage performance, and no lithium precipitation phenomenon at high temperatures.

[0022] Furthermore, the active material of the positive electrode of the present invention is LiNi x Co y Mn zM 1-x-y-z O2 or LiNi x Co y Al z N 1-x-y- z 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. Specifically, the active material of the positive electrode can be, but is not limited to, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNi 0.9 Co 0.05 Mn 0.05 O 2。

[0023] Furthermore, the silicon-based negative electrode of the present invention is any one of a silicon negative electrode, a silicon-carbon negative electrode, and a silicon-oxygen negative electrode. Specifically, the negative electrode sheet is obtained by coating a negative electrode paste on a current collector. The negative electrode paste includes a carbon-based material, CVD vapor-deposited pure silicon, a conductive agent, a binder, and a thickening agent. The mass ratio of the carbon-based material, silicon oxide compound, conductive agent, binder, and thickening agent is 72 - 78:18 - 22:1 - 3:0.5 - 1.5:0.5 - 1.5. Specifically, the carbon-based material can be, but is not limited to, at least one of artificial graphite and natural graphite. The binder can be, but is not limited to, styrene-butadiene rubber. The thickening agent can be, but is not limited to, sodium carboxymethyl cellulose (CMC). Specific Embodiments

[0024] To better illustrate the purpose, technical solution, and beneficial effects of the present invention, the present invention will be further described below with reference to specific embodiments. It should be noted that the methods described in the following embodiments are further explanatory descriptions of the present invention and should not be construed as limitations on the present invention.

[0025] Example 1 (1) Preparation of non-aqueous electrolyte In a glove box filled with argon (O2 < 1 ppm, H2O < 1 ppm), ethylene carbonate (EC), ethyl methyl carbonate (EMC), propylene carbonate (PCA), and diethyl carbonate (DEC) were mixed according to a weight ratio of EC:EMC:PCA:DEC = 4:15:5:2 to obtain 86 g of a non-aqueous organic solvent. Then, 0.5 g of Compound 1 and 0.5 g of Compound 4 were added, dissolved, and stirred well. After that, 13 g of lithium hexafluorophosphate was added and mixed evenly to obtain a non-aqueous electrolyte.

[0026] (2) Preparation of the positive electrode sheet Mix NCM9055, binder PVDF, and conductive agent SuperP evenly at a mass ratio of 95:1:4 to form a lithium-ion battery positive electrode slurry with a certain viscosity. After coating the mixed slurry on both sides of the aluminum foil, dry it and roll it to obtain the positive electrode sheet.

[0027] (3) Preparation of the negative electrode sheet Mix artificial graphite, CVD vapor deposition pure silicon, conductive agent Ketjen black, binder styrene-butadiene rubber, and thickener sodium carboxymethyl cellulose (CMC) evenly at a mass ratio of 76:20:2:1:1 in a deionized water solvent system, then coat it on the copper foil, dry it, and cold press it to obtain the negative electrode sheet.

[0028] (4) Preparation of the lithium-ion battery Make a soft-pack battery cell by winding the positive electrode, separator, and negative electrode, package it with a polymer aluminum-plastic film, fill it with the non-aqueous electrolyte prepared above, and make a lithium-ion battery with a capacity of 1000 mAh after processes such as formation and grading.

[0029] The formulations of the non-aqueous electrolytes of Examples 1-11 and Comparative Examples 1-3 are shown in Table 1. Among them, the steps of preparing the non-aqueous electrolyte and the lithium-ion battery in Examples 2-11 and Comparative Examples 1-3 are the same as those in Example 1.

[0030] Table 1 Formulations of the non-aqueous electrolytes of each example and comparative example

[0031] Perform high-temperature storage tests, internal resistance growth rate tests, thickness growth rate tests, and high-temperature lithium precipitation tests on the lithium-ion batteries made in Examples 1-11 and Comparative Examples 1-3 respectively. The specific test conditions are as follows, and the performance test results are shown in Table 2.

[0032] High-temperature cycle capacity retention performance test At a constant temperature of 25°C, charge the lithium-ion battery at a constant current of 1C until the voltage reaches 4.2V, then charge it at a constant voltage of 4.2V until the current reaches 0.05C, and then discharge it at a constant current of 1C until the voltage reaches 3.0V. Record the first-cycle discharge capacity of the battery as C0. Then place the lithium-ion battery in an incubator at 45°C and let it stand for 30 minutes to reach a constant temperature. Then, under the condition of 45°C, perform 300 charge-discharge cycles at 1C / 1C, and then discharge it at a constant current and constant voltage of 1C / 1C to 3V at a constant temperature of 25°C. Record the discharge capacity as C1. Use the following formula to calculate the capacity retention rate of the lithium-ion battery at 45°C for 300 cycles.

[0033] Capacity retention rate = C1 / C0 × 100%.

[0034] Internal resistance growth rate test At a constant temperature of 25°C, the lithium-ion battery is charged at a constant current of 0.5C until the cut-off voltage of 4.2V, and the initial internal resistance of the battery is recorded. Then, the lithium-ion battery is placed in an incubator at 60°C and left to stand for 30 minutes. After the lithium-ion battery reaches a constant temperature, it is stored for 30 days. After that, the battery after 30 days of storage is charged at a constant current and constant voltage of 0.5C to the cut-off voltage of 4.2V at room temperature, and then discharged at a constant current and constant voltage until the capacity drops to 50% SOC, and the internal resistance of the battery after 30 days of storage is tested.

[0035] Growth rate of internal resistance of the battery after 30 days of high-temperature storage = (Internal resistance of the battery after 30 days of storage - Initial internal resistance) / Initial internal resistance × 100%.

[0036] Thickness growth rate test After the battery is charged at a constant current and constant voltage of 0.5C to 4.2V at 25°C, the mass of the fully charged battery is measured using the drainage method and recorded as m1. After being stored at 60°C for 30D, it is taken out and discharged at a constant current of 0.5C to 3V at room temperature of 25°C, and then the mass of the battery is measured using the drainage method and recorded as m2.

[0037] Growth rate of thickness of the battery after 30 days of high-temperature storage = (Thickness of the battery after 30 days of storage m2 - Thickness of the battery when fully charged for the first time m1) / Thickness of the battery when fully charged for the first time m1 × 100%.

[0038] High-temperature lithium deposition test: At a high temperature of 45°C, for lithium-ion battery ①: ① Charge at a constant current and constant voltage of 1C to 4.2V, with a cut-off rate of 0.05C, and set aside for 5 minutes; ② Discharge at a constant current of 1C to 3V, and set aside for 5 minutes; ③ Repeat steps ①~② for a total of 100 times; ④ Charge at a constant current and constant voltage of 1C to 4.2V, with a cut-off rate of 0.05C, and set aside for 5 minutes; ⑤ Disassemble the interface and observe the lithium deposition situation.

[0039] Table 2 Test results of lithium-ion battery performance

[0040] As can be seen from Table 2, compared with Comparative Examples 1 to 3, the lithium-ion batteries of Examples 1 to 11 have better high-temperature cycle stability, high-temperature storage performance, and no lithium precipitation phenomenon at high temperatures. This is because the present invention introduces Compound A with a carboxylic acid ester fluorine structure and Compound B with a siloxane structure as additives into the non-aqueous electrolyte. Among them, Compound A reduces the HOMO energy level of the electrolyte through its fluorine-containing group, greatly improving the antioxidant stability. At the same time, the fluorine atoms in Compound A form an inorganic SEI layer rich in LiF during the charge and discharge process to enhance the electrode interface stability, and the low-viscosity characteristic of the carboxylic acid ester structure in Compound A also significantly improves the conductivity of the non-aqueous electrolyte. Compound B endows the electrolyte with excellent thermal stability and chemical stability by utilizing the high bond energy (452 kJ / mol) of the Si-O bond. The siloxane structure in Compound B can spontaneously form an anion-rich solvation structure at a low salt concentration due to its unique weak solvation characteristic. This not only improves the redox compatibility with the cathode and anode, but also reduces the electrolyte cost and collector corrosion, effectively inhibiting the growth of lithium dendrites. Therefore, through the synergistic effect of Compound A and Compound B, the present invention enables the non-aqueous electrolyte to form a more stable SEI film during the charge and discharge of the lithium-ion battery, enhances the oxidation stability of the electrolyte, and avoids the oxidation and decomposition of the electrolyte by the highly catalytically active Ni dissolved from the positive electrode, inhibiting the deterioration of the high-nickel positive electrode. At the same time, by optimizing the lithium-ion solvation structure and increasing the conductivity, lithium precipitation is inhibited, and finally, the comprehensive improvement of the lithium-ion battery in terms of high-temperature cycle stability, storage performance, and safety is achieved. 2+ Oxidize and decompose the electrolyte, inhibit the deterioration of the high-nickel positive electrode, and at the same time inhibit lithium precipitation by optimizing the lithium-ion solvation structure and increasing the conductivity, ultimately achieving a comprehensive improvement in the high-temperature cycle stability, storage performance, and safety of the lithium-ion battery.

[0041] Comparing Examples 1 to 5, it can be seen that the lithium-ion battery of Example 4 has better comprehensive performance. This is because Compound 2 has a higher degree of fluorination, a lower HOMO energy level, stronger oxidation resistance compared to Compound 1 and Compound 3, and the double bond in Compound 2 can polymerize with the double bond in Compound 5 to cover the surface of the negative electrode, enhancing the stability of the SEI film and having a stronger ability to accommodate the expansion of the negative electrode. Therefore, when Compound 2 and Compound 5 are used in combination, their improvement in the high-temperature storage performance of the battery is more excellent, and the growth rate of the internal resistance is the smallest.

[0042] Comparing Example 4 with Examples 9 to 11, it can be seen that the lithium-ion battery of Example 10 has better comprehensive performance. This is because the skeleton of FEC is a cyclic carbonate structure, and the intermediate obtained in its electrochemical reaction can polymerize with Compound 2 and 5 to form an SEI component with a higher degree of polymerization, making it more elastic and better able to accommodate the volume expansion of the negative electrode, slowing down the interfacial side reaction between the electrolyte and the negative electrode. Therefore, when Compound 2, Compound 5, and FEC are used synergistically, their performance is better.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it is not limited to the embodiments listed. Those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions 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 represented by formula 1 and compound B represented by formula 2: Wherein, R1 is selected from hydrogen, C1-C6 alkyl; R2 is selected from hydrogen or halogen; R3-R4 are each independently selected from C1-C6 alkyl, C2-C6 alkynyl; R5-R6 are each independently selected from C1-C6 alkyl, C2-C6 alkenyl.

2. The non-aqueous electrolyte according to claim 1, characterized in that, R1 is selected from hydrogen, C1-C3 alkyl; R2 is selected from hydrogen or fluorine; R3-R4 are each independently selected from C1-C3 alkyl, C2-C3 alkynyl; R5-R6 are each independently selected from C1-C3 alkyl, C2-C3 alkenyl.

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 3: 。 4. The non-aqueous electrolyte according to claim 1, characterized in that, The compound B is selected from at least one of compound 4 to compound 6: 。 5. The non-aqueous electrolyte according to claim 1, wherein The mass percentage of the compound A in the non-aqueous electrolyte is 0.05-5%; the mass percentage of the compound B in the non-aqueous electrolyte is 0.05-5%.

6. The non-aqueous electrolyte according to claim 1, wherein, The lithium salt is selected from at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalato)borate, lithium difluorophosphate, lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium lower aliphatic carboxylate, lithium difluorodioxalate phosphate, lithium bis(fluorosulfonyl)imide, lithium chloroborane, and lithium tetraphenylborate.

7. The non-aqueous electrolyte according to claim 1, wherein 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.

8. The non-aqueous electrolyte according to claim 1, characterized in that, It 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.

9. A lithium-ion battery, comprising a positive electrode and a negative electrode, characterized in that, It further includes the non-aqueous electrolyte according to any one of claims 1 to 8.

10. The lithium-ion battery according to claim 9, wherein The active material of the positive electrode is LiNi x Co y Mn z M 1-x-y-z O2 or LiNi x Co y Al z N 1-x-y-z 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.

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