Non-aqueous electrolyte and lithium ion battery containing the same

Abstract

This invention provides 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 non-aqueous organic solvent includes acetonitrile, and the additive includes compound A. The structural formula of compound A is shown in Formula 1. R1 is selected from substituted or unsubstituted C1-C6 hydrocarbon groups, substituted or unsubstituted aromatic groups, and R2, R3, and R4 are each independently selected from substituted or unsubstituted C1-C6 hydrocarbon groups, substituted or unsubstituted aromatic groups, and substituted or unsubstituted amino groups. Compound A in this non-aqueous electrolyte can form a high-quality solid electrolyte membrane (SEI) to suppress the reduction gas generation problem of acetonitrile-containing electrolytes, thereby improving high-temperature storage retention and optimizing the fast-charging performance of acetonitrile-containing batteries. Formula 1

Description

Technical Field

[0001] This invention relates to the field of energy storage device technology, particularly to secondary batteries, and even more particularly to a non-aqueous electrolyte and a lithium-ion battery containing the non-aqueous electrolyte. Background Technology

[0002] In lithium-ion batteries and other electrochemical energy storage devices, carbonate compounds (such as ethylene carbonate EC, diethyl carbonate DEC, and propylene carbonate PC) are the most widely used non-aqueous organic solvents in electrolyte systems. Their core advantage lies in their excellent electrochemical stability, their ability to withstand a wide voltage window, and their good lithium-ion conductivity, which fully meets the basic performance requirements of battery charging and discharging. However, these carbonate solvents still have significant limitations: at low temperatures, their ionic conductivity drops sharply, and their high viscosity hinders lithium-ion migration, directly leading to a decline in the fast-charging performance of lithium-ion batteries and poor adaptability to low-temperature conditions, making it difficult to meet the application requirements in extreme environments.

[0003] To improve the overall performance of carbonate-based electrolytes, researchers commonly introduce acetonitrile (ACN) into the system. Acetonitrile possesses extremely low viscosity and a high dielectric constant, which effectively enhances the migration rate of lithium ions in the electrolyte, thereby significantly improving the overall ionic conductivity. Simultaneously, acetonitrile optimizes the interfacial contact between the electrode and the electrolyte, reducing interfacial impedance and improving charge transfer efficiency. Furthermore, its strong solvation ability can fully dissolve lithium salts (such as lithium hexafluorophosphate (LiPF6) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), increasing the concentration and utilization rate of free lithium ions in the electrolyte. Therefore, the introduction of acetonitrile has a clear promoting effect on improving the low-temperature discharge performance and fast-charging capability of batteries.

[0004] However, the addition of acetonitrile also brings new technical challenges. On the one hand, acetonitrile molecules readily react with lithium hexafluorophosphate to generate HF acid, which continuously corrodes the electrode active material and current collector, exacerbating gas generation inside the battery. On the other hand, acetonitrile readily undergoes a reduction reaction on the graphite anode surface, accompanied by gas generation, and its reduction products cannot form a dense and stable solid electrolyte interphase (SEI) film. The lack of an SEI film makes it difficult to effectively protect the anode, and subsequent side reactions continue to occur, ultimately leading to prominent gas generation problems in lithium-ion batteries, severely impairing the battery's cycle stability and long-term storage performance.

[0005] Based on the aforementioned technical bottlenecks, there is an urgent need to develop new non-aqueous electrolyte systems and supporting lithium-ion battery technologies to overcome the shortcomings of existing technologies where "performance improvement and risk coexist," achieve synergistic optimization of battery low-temperature performance, fast charging capability, and cycle storage performance, and provide technical support for the efficient and stable application of electrochemical energy storage devices. Summary of the Invention

[0006] Based on the above problems, the purpose of this invention is to provide a non-aqueous electrolyte and a lithium-ion battery. Compound A in the non-aqueous electrolyte can form a high-quality solid electrolyte membrane (SEI) to suppress the reduction gas generation problem of electrolytes containing acetonitrile, thereby improving the high-temperature storage retention rate and optimizing the fast-charging performance of batteries containing acetonitrile.

[0007] To achieve the above objectives, the present invention provides a non-aqueous electrolyte comprising a lithium salt, a non-aqueous organic solvent, and an additive. The non-aqueous organic solvent comprises acetonitrile, and the additive comprises compound A. The structural formula of compound A is shown in Formula 1, wherein R1 is selected from substituted or unsubstituted C1-C6 hydrocarbon groups, substituted or unsubstituted aromatic groups, and R2, R3, and R4 are each independently selected from substituted or unsubstituted C1-C6 hydrocarbon groups, substituted or unsubstituted aromatic groups, and substituted or unsubstituted amino groups.

[0008] Formula 1 The additive in the non-aqueous electrolyte of this invention includes compound A as shown in Formula 1, which contains an aminothioformyl group that has a strong affinity for the graphite anode surface. It preferentially adsorbs acetonitrile at the electrode interface and undergoes selective reduction during the first charge, forming a thin and dense SEI layer. Its decomposition products include inorganic components such as Li₂S and phosphides, as well as organic polymers, and possess both high ionic conductivity (10⁻⁶). -7 ~10 -6 Its S / cm and electronic insulation properties effectively prevent acetonitrile from being reduced under low negative potential conditions, thus preventing the cyano and methyl chemical bonds from breaking and decomposing into gases such as methane and nitrogen. It contains phosphonium intrasalt cations (3R-P...). + The thiourea structure adsorbs onto the negatively charged anode surface, forming an internal electrostatic field that guides ion distribution uniformly and inhibits dendrite growth. Simultaneously, the thiourea structure promotes lithium-ion transport, reduces local current density, improves coulombic efficiency, and avoids dendrite nucleation caused by excessively high local concentrations. The strong coordination ability of the amino and sulfur atoms promotes lithium salt dissociation, increases the concentration of free ions, and alters the Li-ion distribution. + The solvation structure lowers the desolvation energy barrier. Therefore, the combination of preferential adsorption on the negative electrode surface by the aminothioformyl group, SEI film formation, dendrite suppression of phosphonium internal salt cations, and regulation of ion transport rate by the thiourea structure can improve the electrochemical performance of acetonitrile-based electrolyte lithium-ion batteries.

[0009] As a technical solution of the present invention, R1 is selected from substituted or unsubstituted C1~C3 alkyl, substituted or unsubstituted C2~C4 alkenyl, substituted or unsubstituted C2~C4 alkynyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, and R2, R3, and R4 are each independently selected from C1~C3 alkyl, substituted or unsubstituted C2~C4 alkenyl, substituted or unsubstituted C2~C4 alkynyl, silyl substituted or unsubstituted amino.

[0010] As a technical solution of the present invention, R1 is selected from substituted or unsubstituted C1~C3 alkyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, and R2, R3, and R4 are each independently selected from C1~C3 alkyl, silyl substituted or unsubstituted amino groups.

[0011] As a technical solution of the present invention, compound A is selected from at least one of compounds one to three.

[0012]

[0013] Compound 1, Compound 2, Compound 3 As a technical solution of the present invention, based on the mass of the lithium salt, the non-aqueous organic solvent and the additive being 100%, the mass percentage of compound A is 0.01~3.00%.

[0014] As one technical solution of the present invention, the lithium salt is selected from at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(oxalate-borate), lithium difluorophosphate, lithium bis(oxalate-borate), lithium difluorooxalate-borate, lithium lower aliphatic carboxylic acids, lithium difluorobis(oxalate-phosphate), lithium bis(fluorosulfonyl)imide, lithium chloroborane, and lithium tetraphenylborate.

[0015] As a technical solution of the present invention, the non-aqueous organic solvent further includes a first solvent, wherein the acetonitrile accounts for 8-25% of the mass of the non-aqueous organic solvent.

[0016] As a technical solution of the present invention, the first 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, butyl carbonate, pentylenetene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl n-propyl carbonate, ethyl n-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.

[0017] A second aspect of the present invention provides a lithium-ion battery, comprising a positive electrode material, a negative electrode material, and an electrolyte, wherein the electrolyte is selected from the aforementioned non-aqueous electrolytes.

[0018] As a technical solution of the present invention, the cathode material is selected from at least one of lithium iron phosphate materials, lithium manganese iron phosphate materials, lithium nickel cobalt manganese oxide materials, lithium nickel cobalt aluminum oxide materials, and lithium cobalt oxide materials.

[0019] As one technical solution of the present invention, the negative electrode material is selected from at least one of artificial graphite, natural graphite, lithium titanate, silicon-carbon composite material and silicon-oxygen composite material. Detailed Implementation

[0020] The non-aqueous electrolyte of this invention, through specific additives, can suppress gas generation problems in electrolytes containing acetonitrile, thereby improving the electrochemical performance of the battery. The lithium-ion battery of this invention may include a positive electrode material, a negative electrode material, and a non-aqueous electrolyte. The cathode material may include layered oxides (such as lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium cobalt oxide) and olivine-type materials (lithium iron phosphate and lithium manganese iron phosphate). Further, lithium nickel cobalt manganese oxide materials may include lithium nickel cobalt manganese oxide, doped or coated lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide materials may include lithium nickel cobalt aluminum oxide, doped or coated lithium nickel cobalt aluminum oxide. The chemical formula of nickel cobalt manganese oxide is LiNi. x Co y Mn z M (1-x-y-z) O2, the chemical formula of nickel cobalt aluminum oxide is LiNi x Co y Al z N (1-x-y-z)O2, where M is at least one of Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V, and Ti, N is at least one of Mn, Mg, Cu, Zn, Sn, B, Ga, Cr, Sr, V, and Ti, 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z ≤ 1. The lithium cobalt oxide-based materials may include lithium cobalt oxide-based materials, doped or coated lithium nickel cobalt manganese oxide lithium cobalt oxide-based materials. The lithium iron phosphate-based materials may include lithium iron phosphate, doped or coated lithium iron phosphate. The lithium manganese iron oxide-based materials may include lithium manganese iron oxide, doped or coated lithium manganese iron oxide.

[0021] The negative electrode material is selected from at least one of artificial graphite, natural graphite, lithium titanate, silicon-carbon composite materials, and silicon-oxygen composite materials.

[0022] The non-aqueous electrolyte includes a lithium salt, a non-aqueous organic solvent, and an additive.

[0023] Based on the total mass of the lithium salt, the non-aqueous organic solvent, and the additive being 100%, the mass ratio of the lithium salt is 5 - 25%, further, the mass ratio of the lithium salt is 8 - 20%, and still further, the mass ratio of the lithium salt is 10 - 15%. As an example, the mass ratio of the lithium salt can be, but is not limited to, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 24%, 25%. The mass ratio of the lithium salt is not limited to the listed values, and other unlisted values within this range are equally applicable.

[0024] The lithium salt is selected from at least one of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethylsulfonyl)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. As an example, the lithium salt is lithium hexafluorophosphate (LiPF6), but not limited thereto.

[0025] Based on the mass of lithium salt, non-aqueous organic solvent, and additives as 100%, the mass percentage of non-aqueous organic solvent is 65-90%. Preferably, the mass percentage of non-aqueous organic solvent is 75-89%. More preferably, the mass percentage of non-aqueous organic solvent is 78-88%. As examples, the mass percentage of non-aqueous organic solvent may be, but is not limited to, 65%, 70%, 80%, 85%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, and 90%.

[0026] The non-aqueous organic solvent includes acetonitrile and a first solvent. Acetonitrile accounts for 8-25% of the mass of the non-aqueous organic solvent. For example, the percentage of acetonitrile may be, but is not limited to, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, and 25%. The first solvent is selected from 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), butyl carbonate (BC), methyl pentyl carbonate (MPC), vinylene carbonate (VEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), and methyl n-propyl carbonate (M). At least one of the following: PC, ethyl n-propyl carbonate, 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).

[0027] The additive includes compound A, the structural formula of which is shown in Formula 1. R1 is selected from substituted or unsubstituted C1-C6 hydrocarbon groups, substituted or unsubstituted aromatic groups, and R2, R3, and R4 are each independently selected from substituted or unsubstituted C1-C6 hydrocarbon groups, substituted or unsubstituted aromatic groups, and substituted or unsubstituted amino groups. Further, R1 is selected from substituted or unsubstituted C1-C3 alkyl groups, substituted or unsubstituted C2-C4 alkenyl groups, substituted or unsubstituted C2-C4 alkynyl groups, substituted or unsubstituted phenyl groups, and substituted or unsubstituted naphthyl groups, and R2, R3, and R4 are each independently selected from C1-C3 alkyl groups, substituted or unsubstituted C2-C4 alkenyl groups, substituted or unsubstituted C2-C4 alkynyl groups, and silyl-substituted or unsubstituted amino groups. Furthermore, R1 is selected from substituted or unsubstituted C1-C3 alkyl, substituted or unsubstituted phenyl, or substituted or unsubstituted naphthyl groups; R2, R3, and R4 are each independently selected from C1-C3 alkyl, silane, or substituted or unsubstituted amino groups. Substituted or unsubstituted C1-C6 hydrocarbon groups refer to substituted or unsubstituted straight-chain or branched saturated hydrocarbon groups containing 1 to 6 carbon atoms. Unsubstituted C1-C6 hydrocarbon groups refer to alkyl groups in which no hydrogen atom is substituted by other atoms or groups, and can be methyl, ethyl, propyl, isopropyl, butyl, isopropyl, butyl, pentyl, hexyl, vinyl, propynyl, isopropynyl, butynyl, isopropynyl, butynyl, pentynyl, or hexynyl. Substituted C1-C6 hydrocarbon groups refer to hydrocarbon groups in which one or more hydrogen atoms are replaced by other atoms or groups (called substituents). Substituents can be halogens (such as fluorine, chlorine, bromine, iodine), hydroxyl groups, amino groups, nitro groups, alkoxy groups, or aryl groups. For example, a methyl group can be replaced by a chlorine atom to form a chloromethyl group (-CH2Cl) or by a hydroxyl group to form a hydroxymethyl group (-CH2OH). Substituted or unsubstituted aromatic groups refer to substituted or unsubstituted phenyl or naphthyl fused-ring compounds, which can be phenyl, naphthyl, or fluorine, alkyl, fluoroalkyl, etc., specifically fluorobenzene, methylbenzene, fluorobenzyl, etc. Substituted or unsubstituted amino groups can be amino groups, or one or two hydrogen atoms can be replaced by alkyl, silyl, etc.

[0028] Formula 1 Compound A is selected from at least one of compounds one through three.

[0029]

[0030] Compound 1, Compound 2, Compound 3 CAS:22793-68-6CAS:61223-97-0CAS:1236036-93-3 Based on the mass of lithium salt, non-aqueous organic solvent, and additives being 100%, the mass percentage of compound A is 0.01% to 3.00%. Further, the mass percentage of compound A is 0.1% to 3.0%. Even further, the mass percentage of compound A is 0.5% to 2.0%. As examples, the mass percentage of compound A may be, but is not limited to, 0.01%, 0.05%, 0.10%, 0.30%, 0.50%, 0.70%, 1.00%, 1.30%, 1.50%, 1.70%, 2.00%, 2.50%, and 3.00%, but is not limited to the listed values; other unlisted values ​​within this range also apply.

[0031] To further illustrate the purpose, technical solution, and beneficial effects of this invention, the following will provide a further description of the invention in conjunction with specific embodiments. It should be noted that, for other raw materials in the embodiments and comparative examples where specific conditions are not specified, they can be carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used where the manufacturer is not specified are all commercially available conventional products.

[0032] Example 1 1.1 Preparation of non-aqueous electrolyte In an argon atmosphere and a vacuum glove box with a moisture content of <1ppm, dimethyl carbonate (DMC), propylene carbonate (PC), methyl acetate (MA), and γ-butyrolactone (GBL) were mixed in a weight ratio of DMC:PC:MA:GBL = 3:6:5:6 to obtain 72.5g of the first solvent. Then, 13.0g of acetonitrile (ACN) was added to obtain 85.5g of non-aqueous organic solvent. Next, 0.5g of compound one was added, dissolved, and stirred thoroughly. Then, 14.0g of LiPF6 was added and mixed evenly to obtain 100g of non-aqueous electrolyte.

[0033] 1.2 Preparation of the positive electrode Lithium iron phosphate material LiFePO4, binder PVDF and conductive agent SuperP are mixed evenly at a mass ratio of 95:1:4 to prepare a lithium secondary battery positive electrode slurry with a certain viscosity. The mixed slurry is coated on both sides of aluminum foil, dried and rolled to obtain the positive electrode sheet.

[0034] 1.3 Preparation of the diaphragm Polyethylene (PE) with a thickness of approximately 15 μm is used as the separator.

[0035] 1.4 Preparation of the negative electrode Artificial graphite, binder PVDF and conductive agent SuperP are mixed evenly in a mass ratio of 90:2:8 to prepare a lithium secondary battery negative electrode slurry of a certain viscosity. The mixed slurry is coated on both sides of copper foil, dried and rolled to obtain the negative electrode sheet.

[0036] 1.5 Preparation of Lithium Secondary Batteries The positive electrode, separator, and negative electrode are stacked in sequence, and then layered as needed. After the tabs are welded, the battery is placed in the aluminum-plastic film of the outer packaging. The prepared non-aqueous electrolyte is injected into the dried bare cell. Vacuum sealing, settling, formation and shaping, and capacity testing are then performed to obtain a 1Ah soft-pack lithium secondary battery.

[0037] The composition and content of the electrolytes in Examples 1-9 and Comparative Example 1 are shown in Table 1. The preparation processes of the lithium-ion battery electrolytes, positive electrode sheets, negative electrode sheets, and lithium-ion batteries in Examples 2-9 and Comparative Example 1 are the same as those in Example 1.

[0038] Table 1. Composition of the electrolytes in Examples 1-9 and Comparative Example 1

[0039] The lithium-ion batteries prepared in Examples 1-9 and Comparative Example 1 were subjected to performance tests under the following conditions, and the results are shown in Table 2.

[0040] (1) High-temperature cycling performance test The lithium-ion battery was placed in a 45°C constant temperature chamber and allowed to stand for 30 minutes to reach a constant temperature. It was then charged at a constant current of 6C until the voltage reached 3.65V, followed by constant voltage charging at 3.65V until the current reached 0.05C. Next, it was discharged at a constant current of 6C until the voltage reached 2.5V. The initial discharge capacity was recorded as C0, and the volume at this point was recorded as V0. This constitutes one charge-discharge cycle. Then, 500 cycles of 6C / 6C charge and discharge were performed at 45°C. The discharge capacity was recorded as C1, and the volume as V1. The capacity retention rate and volume growth rate of the lithium-ion battery were calculated using the following formulas.

[0041] Capacity retention rate = C1 / C0 × 100% Volume growth rate = V1 / V0 × 100% (2) High-temperature storage performance test The lithium-ion battery was charged at a constant current of 1C to a voltage of 3.65V at a constant temperature of 25℃, then charged at a constant voltage of 3.65V to a current of 0.05C, and then discharged at a constant current of 1C to a voltage of 2.5V. The first discharge capacity of the battery was recorded as C0. The lithium-ion battery was then placed in a constant temperature chamber at 60℃ and left to stand for 30 minutes to allow it to reach a constant temperature. After being stored at 60℃ for 15 days, it was discharged at a constant current of 1C / 1C at a constant temperature of 25℃. The lithium-ion battery was discharged to 2.5V, and the discharge capacity was recorded as C1. Then, it was charged again at a constant temperature of 25℃ with a constant current of 1C to a voltage of 3.65V. Then, it was charged at a constant voltage of 3.65V to a current of 0.05C. After being stored at 60℃ for 15 days, it was discharged at a constant temperature of 25℃ with a constant current and constant voltage of 1C / 1C to a voltage of 2.5V, and the discharge capacity was recorded as C2. The capacity retention rate of the lithium-ion battery after 15 days and 30 days of storage will be calculated using the following formulas.

[0042] 15-day storage capacity retention rate = C1 / C0 × 100% 30-day storage capacity retention rate = C2 / C0 × 100% Table 2 Performance test results of lithium-ion batteries from Examples 1-9 and Comparative Example 1

[0043] As can be seen from the results in Table 2, the lithium-ion batteries of Examples 1 to 9 have good high-temperature storage performance. After 500 cycles at 45°C and 6C, they can still maintain a capacity retention rate of more than 85% and a volume growth rate of less than 30%, indicating that the compound A of the present invention can significantly suppress the reduction gas generation problem of electrolytes containing acetonitrile.

[0044] Further comparison of Examples 1-3 shows that Compound A has the best performance when it is Compound II. This is because the strong electron-withdrawing effect of the naphthalene ring in the molecule allows it to be preferentially reduced at the negative electrode before acetonitrile, thus constructing a dense and stable inorganic-organic composite SEI film. This effectively blocks the reduction and decomposition of acetonitrile, inhibits hydrolysis and gas production caused by trace amounts of water, and at the same time complexes metal impurities and improves the long-term stability of the interface.

[0045] Comparing Examples 2 and 4-7, it can be seen that Example 5 has the best high-temperature storage performance and high-temperature fast-charge cycle performance, indicating that the mass percentage of compound A is better when it is below 1%.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A non-aqueous electrolyte, characterized in that, The mixture includes lithium salts, a non-aqueous organic solvent, and additives. The non-aqueous organic solvent includes acetonitrile, and the additives include compound A, whose structural formula is shown in Formula 1. In this formula, R1 is selected from substituted or unsubstituted C1-C6 hydrocarbon groups, substituted or unsubstituted aromatic groups, and R2, R3, and R4 are each independently selected from substituted or unsubstituted C1-C6 hydrocarbon groups, substituted or unsubstituted aromatic groups, and substituted or unsubstituted amino groups. Formula 1.

2. The non-aqueous electrolyte according to claim 1, characterized in that, R1 is selected from substituted or unsubstituted C1-C3 alkyl, substituted or unsubstituted C2-C4 alkenyl, substituted or unsubstituted C2-C4 alkynyl, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, and R2, R3, and R4 are each independently selected from C1-C3 alkyl, substituted or unsubstituted C2-C4 alkenyl, substituted or unsubstituted C2-C4 alkynyl, silyl substituted or unsubstituted amino.

3. The non-aqueous electrolyte according to claim 1, characterized in that, R1 is selected from substituted or unsubstituted C1-C3 alkyl, substituted or unsubstituted phenyl, or substituted or unsubstituted naphthyl groups, while R2, R3, and R4 are each independently selected from C1-C3 alkyl or silyl substituted or unsubstituted amino groups.

4. The non-aqueous electrolyte according to claim 1, characterized in that, Compound A is selected from at least one of compounds one through three. Compound 1, Compound 2, Compound 3.

5. The non-aqueous electrolyte according to claim 1, characterized in that, Based on the mass of the lithium salt, the non-aqueous organic solvent, and the additive being 100%, the mass percentage of compound A is 0.01~3.00%.

6. 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 bis(trifluoromethanesulfonyl)imide, lithium bis(oxalate-borate), lithium difluorophosphate, lithium bis(oxalate-borate), lithium difluorooxalate-borate, lithium lower aliphatic carboxylic acids, lithium difluorobis(oxalate-phosphate), lithium bis(fluorosulfonyl)imide, lithium chloroborane, and lithium tetraphenylborate.

7. The non-aqueous electrolyte according to claim 1, characterized in that, The non-aqueous organic solvent further includes a first solvent, wherein the acetonitrile accounts for 8-25% of the mass of the non-aqueous organic solvent.

8. The non-aqueous electrolyte according to claim 7, characterized in that, The first 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, butyl carbonate, pentylenetene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl n-propyl carbonate, ethyl n-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. A lithium-ion battery, comprising a positive electrode material, a negative electrode material, and an electrolyte, characterized in that, The electrolyte is selected from the non-aqueous electrolyte described in any one of claims 1 to 8.

10. The lithium-ion battery according to claim 9, characterized in that, The positive electrode material is selected from at least one of lithium iron phosphate materials, lithium manganese iron phosphate materials, lithium nickel cobalt manganese oxide materials, lithium nickel cobalt aluminum oxide materials, and lithium cobalt oxide materials, and the negative electrode material is selected from at least one of artificial graphite, natural graphite, lithium titanate, silicon-carbon composite materials, and silicon-oxygen composite materials.

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