A lithium-ion battery electrolyte and battery

Abstract

This invention discloses a lithium-ion battery electrolyte and battery. The electrolyte comprises a lithium salt, an organic solvent, a first additive, and a second additive. The first additive is at least one selected from compounds 1 to 4 with specific structures, which can release unsaturated compounds and polymerize to form a high-temperature resistant polymer film during negative electrode reduction. The second additive is at least one selected from phosphoric anhydride compounds represented by specific structural formula 2, which has the functions of removing acid and water and stabilizing the system. Through the synergistic effect of the first and second additives, this invention can construct an SEI film with both high stability and low impedance on the graphite negative electrode surface, effectively suppressing the intercalation of solvent molecules and the decomposition of the electrolyte at high temperatures, significantly improving the high-temperature cycle life and high-temperature storage performance of the battery, and is particularly suitable for the fields of power batteries and energy storage batteries with stringent high-temperature performance requirements.

Description

Technical Field

[0001] This invention relates to a lithium-ion battery electrolyte and battery, belonging to the field of lithium battery technology. Background Technology

[0002] Ternary materials, due to their advantages such as high specific capacity and high energy density, have become one of the mainstream choices for cathode materials in lithium-ion batteries. The NCM / graphite system formed by combining ternary materials with graphite anodes is widely used in various power batteries and energy storage batteries. However, when this system is used or stored in high-temperature environments (such as above 45°C), the electrolyte is prone to decomposition, and the SEI film on the graphite anode surface is unstable, leading to accelerated battery capacity decay, increased internal resistance, and shortened cycle life, which seriously restricts its reliability in high-temperature applications.

[0003] In existing technologies, battery performance is typically improved by optimizing the electrolyte solvent system, lithium salt composition, or adding conventional functional additives (such as VC, FEC, DTD, etc.). However, these solutions offer limited improvement in high-temperature performance. On one hand, the SEI film formed by conventional additives is prone to decomposition or swelling at high temperatures; on the other hand, solvent molecules in the electrolyte are easily embedded in the graphite anode at high temperatures, leading to a breakdown of the anode structure and consequently affecting the overall cycle stability of the battery. Furthermore, these solutions have limited effectiveness in improving high-temperature storage and high-temperature cycling performance.

[0004] Using novel electrolyte additives is an effective way to improve the performance of lithium-ion batteries. Among them, sulfonate compounds are widely used as electrolyte additives. Patent CN110668978B reports a disulfonate compound, which can form a stable SEI film on the negative electrode surface and inhibit the dissolution of metal ions from the positive electrode, thereby improving the high and low temperature performance of the battery. However, the first additive involved in this invention, in addition to possessing the functions of disulfonate compounds and traditional sulfonate compounds, can also generate products containing α,β-unsaturated structures (-CH=CH-). These unsaturated small molecule free radicals rapidly undergo free radical polymerization on the graphite negative electrode surface, forming a dense and uniform polyolefin polymer film. This polymer film has good flexibility and high temperature resistance, and can tightly cover the graphite negative electrode surface, further improving the high-temperature performance of the battery.

[0005] Therefore, developing an electrolyte system that can form a stable, dense, and high-temperature resistant SEI film on the surface of a graphite anode while inhibiting solvent molecule intercalation and electrolyte decomposition is of great significance for improving the high-temperature performance of ternary / graphite lithium-ion batteries. Summary of the Invention

[0006] The purpose of this invention is to provide a lithium-ion battery electrolyte. By introducing a sulfur-containing additive (first additive) whose reduction product can polymerize to form a high-temperature resistant polymer film, and compounding it with a phosphoric anhydride additive (second additive) with deacidification and dehydration functions, an electrolyte system that can synergistically enhance the efficiency, effectively improve the stability of the graphite anode interface, and suppress high-temperature side reactions is constructed, thereby obtaining a lithium-ion battery with excellent high-temperature cycling and high-temperature storage performance.

[0007] The lithium-ion battery electrolyte provided by the present invention includes a first additive, a second additive, a conventional additive, a lithium salt, and an organic solvent; The first additive is selected from any one of compounds 1-4:

[0008] The second additive is a phosphoric anhydride compound.

[0009] Preferably, the structural formula of the phosphoric anhydride compound is shown in Formula 2:

[0010] In Formula 2, R1, R2, and R3 are each independently selected from C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halogenated hydrocarbon groups, cyclic hydrocarbon groups, cyano groups, and phenyl groups.

[0011] Specifically, the second additive is selected from at least one of the following compounds:

[0012] In this invention, any one of compounds 1 to 4 is used as the first additive, and a phosphoric anhydride compound is used as the second additive.

[0013] The first additive used in this invention is a sulfonate compound, similar to traditional sulfonate compounds and disulfonate compounds. It has a high reduction potential (higher than solvent molecules) and preferentially undergoes a reduction reaction on the graphite anode surface during the first charge of the battery, prior to solvent molecules. Its reduction products include conventional SEI film components such as lithium sulfate and lithium sulfite. These compounds can rapidly conduct lithium ions. However, in addition to possessing the functions of disulfonate compounds and traditional sulfonate compounds, the first additive involved in this invention can also generate products containing α,β-unsaturated structures (-CH=CH-). These unsaturated small molecule free radicals rapidly undergo free radical polymerization on the graphite anode surface, forming a dense and uniform polyolefin polymer film. This polymer film has good flexibility and high-temperature resistance, and can tightly cover the graphite anode surface. The inorganic-organic composite SEI film formed by this polymer film and conventional additives (such as VC and FEC) works synergistically to prevent solvent molecules and electrolyte decomposition products from embedding into the graphite layers, avoiding expansion and damage to the anode structure. Furthermore, it inhibits the decomposition of lithium salts and solvents, reducing gas generation at high temperatures.

[0014] Taking compound 1 as an example, its negative electrode reduction product, compared to conventional vinyl sulfate additives (DTD, MMDS, PS, etc.), also contains acrolein (C3H4O), a unique unsaturated compound. Its high-temperature performance improvement is significantly superior to that of conventional vinyl sulfate additives. The reduction products of the other three additives also include similar unsaturated compounds, achieving the effect of improving the high-temperature performance of the battery.

[0015] While sulfur-containing functional additives in this invention improve high-temperature performance, they often introduce sulfonic acid, leading to increased electrolyte acidity. To address this issue, this invention introduces a second additive: phosphoric anhydride compounds. These compounds react chemically with acidic substances in the electrolyte to generate stable fluorophosphate compounds. These compounds are chemically stable, do not undergo secondary decomposition, and can participate in electrode surface film formation without negatively impacting electrolyte performance. Furthermore, a typical Lewis acid-type dehydrating agent, containing highly reactive double bonds and bridging bonds, exhibits a much stronger affinity for water than other components in the electrolyte, thus providing dehydration and deacidification.

[0016] In the lithium-ion battery electrolyte of the present invention, the mass percentage of the first additive is 0.1% to 10%, and the mass percentage of the second additive is 0.1% to 10%.

[0017] In the lithium-ion battery electrolyte of the present invention, the concentration of the lithium salt is 0.5–1.5 mol / L; This invention limits the lithium salt concentration to 0.5–1.5 M, ensuring that the electrolyte possesses sufficient ionic conductivity and suitable physicochemical properties, while also achieving a good synergistic effect with the first and second additives of this invention. Together, they construct an electrolyte system for lithium-ion batteries that combines low impedance and excellent high-temperature performance. Beyond this range, it becomes difficult to meet the aforementioned performance requirements.

[0018] The lithium salt is selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium dioxarate borate, lithium difluorooxarate borate, lithium difluorooxarate phosphate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethylsulfonyl)imide.

[0019] In the lithium-ion battery electrolyte of this invention, the conventional additive has a mass percentage content of 0.1% to 5%. The conventional additives are selected from one or more of the following: vinylene carbonate, fluoroethylene carbonate, vinyl sulfate, 1,3-propane sulpholactone, 1,4-butane sulpholactone, methane disulfonate, tris(trimethylsilane) phosphate, and tris(trimethylsilyl)borate. This invention constructs a multi-layered, multi-functional electrolyte additive system by introducing appropriate amounts of conventional additives. This system consists of a first additive (primarily for film formation, providing high-temperature stability), a second additive (for acid and water removal, maintaining system stability), and a conventional additive (to assist film formation and optimize ion conduction). The synergistic effect of these three additives enables precise control of the electrode interface, allowing the battery to maintain low impedance while achieving excellent high-temperature cycling and high-temperature storage performance.

[0020] The organic solvent is a carbonate solvent and / or a carboxylic acid ester solvent; The carbonate solvents include linear carbonates and / or cyclic carbonates, wherein the linear carbonate is at least one of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, and the cyclic carbonate is at least one of ethylene carbonate, fluoroethylene carbonate, and propylene carbonate. The carboxylic acid ester solvent is at least one of propyl acetate, ethyl acetate, propyl propionate, and ethyl propionate.

[0021] This invention optimizes the types and ratios of organic solvents to create a solvent environment highly compatible with the first and second additives. This solvent system not only ensures efficient dissociation of lithium salts and rapid lithium ion transport, but also provides favorable conditions for the film-forming reaction of the first additive, while maintaining the overall chemical stability of the electrolyte. This is a crucial foundation for the synergistic effect of the additive combination in this invention.

[0022] Based on the lithium-ion battery electrolyte, the present invention also provides a lithium-ion battery, including a positive electrode, a negative electrode, a separator, and an electrolyte.

[0023] The positive electrode active material of the positive electrode sheet is at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide; the negative electrode active material of the negative electrode sheet is one or more of natural graphite, artificial graphite, silicon, and lithium titanate.

[0024] The lithium-ion battery electrolyte of this invention exhibits significantly improved high-temperature performance due to the unique synergistic effect of its first and second additives, making it particularly suitable for power batteries and energy storage batteries with stringent safety and lifespan requirements. By constructing a highly thermally stable, low-impedance electrode / electrolyte interface, this lithium-ion battery electrolyte fundamentally solves the problem of rapid performance degradation in existing batteries at high temperatures. Its low initial impedance, excellent high-temperature cycle retention rate, and high-temperature storage recovery rate perfectly meet the requirements of power batteries for high power output and long lifespan, and also align with the requirements of energy storage batteries for high safety and long-term stability.

[0025] The lithium-ion battery electrolyte of this invention incorporates a specific combination of additives, specifically sulfur-containing functional additives whose reduction products include unsaturated compounds and phosphoric anhydride compounds that remove water and acid and regulate membrane composition. The combination of these two additives effectively improves the SEI film of lithium-ion batteries, reduces the corrosion of the positive electrode by HF, and improves interfacial kinetics, thereby significantly enhancing the high-temperature storage stability and cycle life of the battery and ensuring the electrochemical and safety performance of lithium-ion batteries. Detailed Implementation

[0026] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0027] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0028] The present invention aims to solve the technical problems of existing lithium-ion batteries (especially ternary / graphite systems) with short cycle life, poor storage performance, rapid capacity decay and large internal resistance growth under high temperature environment. To this end, it provides a lithium-ion battery electrolyte with excellent high temperature performance and a lithium-ion battery containing the electrolyte.

[0029] The invention is characterized by a specific combination of additives in the electrolyte. The electrolyte of this invention comprises a lithium salt, an organic solvent, a first additive, a second additive, and conventional additives. The first additive is at least one selected from compounds 1-4 having a specific structure.

[0030] These sulfur-containing functional additives possess high reduction potentials, enabling them to preferentially undergo reduction reactions on the graphite anode surface during the first charge of the battery, prior to solvent molecules. This reduction process not only produces conventional SEI film components such as lithium sulfate and lithium sulfite, but more importantly, it breaks the SC bonds in the molecules, releasing products containing α,β-unsaturated structures (-CH=CH-). These unsaturated small molecule free radicals rapidly polymerize on the anode surface, forming a dense, uniform polyolefin polymer film with excellent flexibility and high-temperature resistance. The second additive is at least one of the phosphoric anhydride compounds shown in specific structural formula 2. As a Lewis acid-type dehydrating agent, this compound can chemically react with acidic substances such as sulfonic acid that may be introduced by the first additive, generating stable fluorophosphate compounds, thus avoiding the negative impact of increased acidity on battery performance. Furthermore, it has a strong affinity for water, effectively removing trace amounts of water from the electrolyte, inhibiting lithium salt decomposition and solvent oxidation, and reducing gas generation at high temperatures.

[0031] This invention constructs a multi-layered, highly stable electrode / electrolyte interface through the synergistic effect of a first additive and a second additive. The polyolefin polymer film formed by the first additive, in conjunction with the inorganic-organic composite SEI film formed by conventional additives (such as VC and FEC), effectively prevents solvent molecules from embedding into the graphite interlayer, avoiding structural expansion and damage to the negative electrode. The acid and water removal functions of the second additive maintain the long-term chemical stability of the electrolyte system. These two additives complement each other, jointly solving the bottleneck problem of limited high-temperature performance improvement under single-additive solutions.

[0032] This invention provides an electrolyte system that can form a stable, dense, and high-temperature resistant SEI film on the surface of a graphite anode, while effectively suppressing solvent molecule intercalation and electrolyte decomposition, thus providing a practical and effective technical solution for improving the high-temperature performance of ternary / graphite lithium-ion batteries.

[0033] Example 1 (1) Preparation of electrolyte: Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed at a mass ratio of EC:EMC = 3:7. After mixing, lithium hexafluorophosphate (LiPF6) was added. After the lithium salt was completely dissolved, conventional additives, compound 1, and compound 2-1 were added to obtain the electrolyte. In the above electrolyte, the concentration of lithium hexafluorophosphate was 1M, the mass ratio of conventional additive VC was 1.5%, the mass percentage of compound 1 was 1.5%, and the mass percentage of compound 2-1 was 1.0%.

[0034] (2) Preparation of positive electrode: Ternary material LiNi0 0.7 C0 0.1 Mn 0.2Conductive agent Super P, binder PVDF and carbon nanotubes (CNT) were mixed evenly in a mass ratio of 97.2:1.8:1:1 to prepare a lithium-ion battery positive electrode slurry. The slurry was coated on both sides of an aluminum foil, dried at 85°C and then cold-pressed. The foil was then slit and sliced, and dried under vacuum at 85°C for 4 hours to obtain the positive electrode sheet.

[0035] (3) Preparation of negative electrode: Artificial graphite was mixed with conductive agent Super P, thickener CMC, and binder SBR (styrene-butadiene rubber latex) in a mass ratio of 94.5:1.5:1.5:2.5 to prepare a lithium-ion battery negative electrode slurry. The slurry was coated on both sides of a copper foil, dried, rolled, and then dried under vacuum at 85°C for 4 hours to obtain the negative electrode sheet.

[0036] (4) Manufacturing lithium-ion batteries: The positive electrode, negative electrode and separator prepared above are stacked to form a lithium-ion battery cell. The cell is then vacuum baked at 85°C for 48 hours and injected with the electrolyte to obtain a lithium-ion battery with a capacity of 3Ah.

[0037] Examples 2 to 14 and Comparative Examples 1 to 10 changed the specific proportions and types of substances in the electrolyte and obtained lithium-ion batteries with reference to the preparation method of Example 1. The electrolyte formulations are shown in Table 1 below.

[0038] Table 1 Electrolyte composition of the examples and comparative examples

[0039] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that only 1.5 wt% of Compound 1 was added, and a lithium-ion battery was finally obtained.

[0040] Comparative Example 2 The difference between Comparative Example 2 and Example 5 is that only 2.0 wt% of Compound 2 was added, and a lithium-ion battery was finally obtained.

[0041] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that only 1.0 wt% of compound 2-1 was added, and a lithium-ion battery was finally obtained.

[0042] Comparative Example 4 The difference between Comparative Example 4 and Example 5 is that only 1.3 wt% of compound 2-2 was added, and a lithium-ion battery was finally obtained.

[0043] Comparative Example 5 The difference between Comparative Example 5 and Comparative Example 1 is that 1.5 wt% of the conventional additive DTD was added to replace compound 1, and a lithium-ion battery was finally obtained.

[0044] Comparative Example 6 The difference between Comparative Example 6 and Comparative Example 1 is that 1.5 wt% of the conventional additive MMDS was added to replace Compound 1, and a lithium-ion battery was finally obtained.

[0045] Comparative Example 7 The difference between Comparative Example 7 and Comparative Example 1 is that 1.5 wt% of conventional additive DTD and 0.5% acrolein (C3H4O) were added to replace compound 1, and a lithium-ion battery was finally obtained.

[0046] Comparative Example 8 The difference between Comparative Example 8 and Comparative Example 3 is that 1.0 wt% of the conventional additive TMSP was added to replace compound 2-1, and a lithium-ion battery was finally obtained.

[0047] Comparative Example 9 The difference between Comparative Example 9 and Example 1 is that 1.5 wt% of conventional additive DTD was added to replace compound 1, and 1.0 wt% of conventional additive TMSP was added to replace compound 2-1 to finally obtain a lithium-ion battery.

[0048] The batteries of the above embodiments and comparative examples were subjected to performance tests, and the specific test methods are as follows: (1) Initial DC Impedance (DCR) Test After capacity testing, the experimental battery was charged to 50% SOC. After resting for 30 minutes, the sampling voltage V0 at the start of discharge was recorded. Then, the battery was discharged at a 3C current I for 10 seconds, and the sampling voltage V1 at the end of discharge was recorded. The initial DC discharge impedance DCR of the experimental battery was calculated as (V1-V0) / I.

[0049] (2) Cyclic performance test Under test conditions of 25℃ and 45℃, the experimental batteries were subjected to charge-discharge cycle performance tests at a charge-discharge rate of 1C. The charge-discharge voltage range was set to 2.8-4.25V. The batteries were cycled for 600 cycles at room temperature and 400 cycles at high temperature. The DCR was measured every 100 cycles, and the capacity retention rate and DCR growth rate were recorded.

[0050] (3) High-temperature storage performance test Batteries from Examples 1-14 and Comparative Examples 1-9 were charged to 4.35V at 0.2C constant current and constant voltage at 25℃, with a cutoff current of 0.05C. They were then discharged to 2.8V at 0.2C constant current, and the discharge capacity Q0 was recorded as the initial discharge capacity. Subsequently, the batteries were charged to 4.45V at 0.2C constant current and constant voltage, with a cutoff current of 0.05C. The fully charged experimental batteries were then placed in a 60℃ oven for 28 days. After high-temperature storage, the cells were first discharged to 2.8V at 0.2C constant current, and the discharge capacity Q1 was recorded. Then, they were charged to 4.35V at 0.2C constant current and constant voltage, with a cutoff current of 0.05C. Finally, they were discharged to 2.8V at 0.2C constant current, and the discharge capacity Q2 was recorded. This process was repeated for three parallel experimental batteries, and the average value was taken. The high-temperature storage capacity retention rate = Q1 / Q0*100%, and the high-temperature storage capacity recovery rate = Q2 / Q0*100%.

[0051] (4) High-temperature storage retention and recovery rate at 60℃ Under test conditions of 25℃ and 45℃, the experimental batteries were subjected to charge-discharge cycle performance tests at a charge-discharge rate of 1C. The charge-discharge voltage range was set to 2.8-4.25V. The batteries were cycled for 600 cycles at room temperature and 400 cycles at high temperature. The DCR was measured every 100 cycles, and the capacity retention rate and DCR growth rate were recorded.

[0052] The test results are shown in Table 2: Table 2 Test results for each embodiment and comparative example

[0053] As can be seen from Table 2: 1) The results of Examples 1-14 and Comparative Examples 1-9 show that, compared with traditional additives (such as DTD, MMDS and TMSP) and their combinations, the electrolyte additive combination of the present invention can effectively reduce the initial room temperature DCR and low temperature DCR, and improve the normal and high temperature cycling and high-temperature performance.

[0054] 2) The test results of Comparative Examples 1-4 and Examples 1 and 4 show that, compared with a single novel additive, the electrolyte additive combination of the present invention improves the DCR growth rate at normal and high temperatures and enhances the normal and high temperature cycling and high-temperature performance of the battery.

[0055] 3) The test results of Comparative Examples 1-2 and Comparative Examples 5-7 show that the first additive of the present invention, namely the sulfonate compound, has better high-temperature cycling and high-temperature storage performance than conventional sulfate compounds (DTD, MMDS). This is mainly because the first additive, namely the sulfonate compound, can form an unsaturated compound on the negative electrode, which can polymerize on the surface of the negative electrode to form a denser SEI film, effectively improving high-temperature performance.

[0056] 4) The test results of Comparative Example 7 and Comparative Example 5 show that the combination of DTD and acrolein has better high-temperature cycling and high-temperature storage performance than DTD alone, verifying the above conjecture.

[0057] 5) The test results of Comparative Examples 3-4 and Comparative Example 8 show that the second additive of the present invention, namely the phosphoric anhydride additive, can effectively reduce the initial room temperature DCR and low temperature DCR compared with conventional phosphate ester compounds (TMSP).

[0058] In summary, it can be seen that the electrolyte of the present invention, which contains electrolyte additives with specific structures, can reduce the growth rate of DCR at normal and low temperatures and at normal and high temperatures, effectively improve the battery's normal and high temperature cycling and high-temperature performance, and is very suitable for power batteries, energy storage batteries and other scenarios that require improved high-temperature storage and high-temperature cycling performance.

[0059] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A lithium-ion battery electrolyte, comprising a first additive, a second additive, a conventional additive, a lithium salt, and an organic solvent; The first additive is selected from any one of compounds 1-4: The second additive is a phosphoric anhydride compound.

2. The lithium-ion battery electrolyte according to claim 1, characterized in that: The structural formula of the phosphoric anhydride compounds is shown in Formula 2: In Formula 2, R1, R2, and R3 are each independently selected from C1-C5 saturated hydrocarbon groups, unsaturated hydrocarbon groups, halogenated hydrocarbon groups, cyclic hydrocarbon groups, cyano groups, and phenyl groups.

3. The lithium-ion battery electrolyte according to claim 2, characterized in that: The second additive is selected from at least one of the following compounds: 。 4. The lithium-ion battery electrolyte according to any one of claims 1-3, characterized in that: In the lithium-ion battery electrolyte, the mass percentage of the first additive is 0.1% to 10%, and the mass percentage of the second additive is 0.1% to 10%.

5. The lithium-ion battery electrolyte according to any one of claims 1-3, characterized in that: In the lithium-ion battery electrolyte, the concentration of the lithium salt is 0.5–1.5 mol / L; The lithium salt is selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium dioxarate borate, lithium difluorooxarate borate, lithium difluorooxarate phosphate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethylsulfonyl)imide.

6. The lithium-ion battery electrolyte according to any one of claims 1-3, characterized in that: In the lithium-ion battery electrolyte, the mass percentage of the conventional additive is 0.1% to 5%. The conventional additives are selected from one or more of the following: vinylene carbonate, fluoroethylene carbonate, vinyl sulfate, 1,3-propane sulpholactone, 1,4-butane sulpholactone, methane disulfonate, tris(trimethylsilane) phosphate, and tris(trimethylsilyl)borate.

7. The lithium-ion battery electrolyte according to any one of claims 1-3, characterized in that: The organic solvent is a carbonate solvent and / or a carboxylic acid ester solvent; The carbonate solvents include linear carbonates and / or cyclic carbonates, wherein the linear carbonate is at least one of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, and the cyclic carbonate is at least one of ethylene carbonate, fluoroethylene carbonate, and propylene carbonate. The carboxylic acid ester solvent is at least one of propyl acetate, ethyl acetate, propyl propionate, and ethyl propionate.

8. A lithium-ion battery, comprising a positive electrode, a negative electrode, a separator, and an electrolyte, wherein the electrolyte is the lithium-ion battery electrolyte according to any one of claims 1-7.

9. The lithium-ion battery according to claim 8, characterized in that: The positive electrode active material is at least one of lithium cobalt oxide, lithium manganese oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide; the negative electrode active material is one or more of natural graphite, artificial graphite, silicon, and lithium titanate.

10. The application of the lithium-ion battery electrolyte according to any one of claims 1-7 or the lithium-ion battery according to claim 8 or 9 in the preparation of power batteries or energy storage batteries.

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