Non-aqueous electrolyte and lithium ion battery thereof

Abstract

The invention discloses 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, the additive comprises at least one of cyclic sulfonic anhydride compounds represented by a structural formula I and a structural formula II, and a sulfonic acid silicon ester compound represented by a structural formula III, r1 to R14 are respectively and independently selected from hydrogen, halogen, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C2-C6 alkenyl and substituted or unsubstituted C2-C6 alkynyl, and m is selected from 0 or 1. According to the non-aqueous electrolyte, the unsaturated cyclic sulfonic anhydride salt compound and the sulfonic acid silicon ester compound are introduced into the non-aqueous electrolyte as additives, so that the high-temperature cycle performance and the high-temperature storage performance of the ternary lithium ion battery under high voltage can be effectively improved, and meanwhile, the internal resistance can be effectively reduced. The structural formula I, the structural formula II and the structural formula III are shown.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and in particular to a non-aqueous electrolyte and its lithium-ion battery. Background Technology

[0002] Ternary layered cathode materials, represented by nickel-cobalt-manganese (NCM) / nickel-cobalt-aluminum (NCA), have become the mainstream technology for power batteries due to their high specific capacity (>200 mAh / g) and energy density (≥750 Wh / L). However, when the operating voltage is increased to above 4.4 V (vs. Li+ / Li) to tap the capacity potential, their inherent defects are significantly exposed: high delithiation state triggers irreversible phase transition and lattice oxygen precipitation, leading to loss of active material; the electrode / electrolyte interface side reactions surge, generating a high-resistivity CEI film accompanied by the release of gases such as CO2 / O2, causing swelling and safety risks; at the same time, transition metal ions dissolve and migrate to the negative electrode, destroying the integrity of the SEI film and accelerating the consumption of active lithium, which seriously restricts the cycle life and safety under high voltage conditions.

[0003] Current mainstream carbonate-based electrolytes (such as the EC-EMC-DMC system) suffer from multiple failures under high-voltage conditions: The carbonate solvent (EC oxidation potential < 4.3V) undergoes severe oxidative decomposition, leading to increased electrolyte viscosity, decreased conductivity, and significant gas production (CO2 / alkanes); lithium salts, such as LiPF6, decompose at high temperatures / in trace amounts of water to produce highly corrosive HF, which erodes the positive electrode lattice (accelerating metal dissolution) and corrodes the negative electrode SEI film; the CEI film formed under high voltage is porous and has excessively high impedance, failing to inhibit continuous electrolyte decomposition and ion migration; simultaneously, traditional additives (VC / FEC) fail prematurely under high voltage, and novel additives (boron / phosphorus-based) exhibit compatibility defects. These electrolyte failures, combined with the high-voltage instability of ternary materials, create a vicious cycle, resulting in a surge in battery internal resistance, uncontrolled gas production, and a sharp decline in cycle life. Therefore, there is an urgent need to develop a non-aqueous electrolyte and its lithium-ion battery to address the shortcomings of existing technologies. Summary of the Invention

[0004] In view of the above problems, the purpose of this invention is to provide a non-aqueous electrolyte and its lithium-ion battery. Introducing unsaturated cyclic sulfonic anhydride salt compounds and sulfonic acid silicon ester compounds as additives into the non-aqueous electrolyte can effectively improve the high-temperature cycle performance and high-temperature storage performance of ternary lithium-ion batteries under high voltage, while also effectively reducing internal resistance.

[0005] 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, wherein the additive comprises at least one cyclic sulfonic anhydride compound selected from those shown in structural formula I and structural formula II.

[0006] Structural Formula I Structural Formula II And, sulfonate silicate compounds represented by structural formula III

[0007] Structural Form III Among them, R1~R 14 Each is independently selected from hydrogen, halogen, substituted or unsubstituted C1~C6 alkyl, substituted or unsubstituted C2~C6 alkenyl, substituted or unsubstituted C2~C6 alkynyl, and m is selected from 0 or 1.

[0008] Compared with existing technologies, the additives in the non-aqueous electrolyte of this invention include at least one cyclic sulfonic anhydride compound selected from structural formulas I and II and sulfonate silicate compound selected from structural formula III. The cyclic sulfonic anhydride compound preferentially undergoes reduction and decomposition on the negative electrode surface to form a stable SEI film, effectively reducing side reactions between the electrolyte and the negative electrode material and improving the structural stability of the negative electrode material. However, its unsaturated cyclic structure is prone to ring-opening polymerization or decomposition at high temperatures, generating high molecular weight products, increasing electrolyte viscosity, reducing ion migration rate, and potentially covering electrode active sites, thus deteriorating high-temperature cycling performance. Therefore, this invention introduces sulfonate silicate compound of structural formula II into the non-aqueous electrolyte to synergistically regulate the composition of the solid electrolyte membrane. The Si-O bond (Si-O) between silicon atoms and sulfonate groups in the structure of sulfonate silicate compound has high reactivity and can be attacked by water (H2O) and acids (such as HF). Therefore, it can reduce electrolyte decomposition and gas generation at high temperatures, suppress the increase of water acid value in the battery, and thus improve the battery's room-temperature cycling and high-temperature storage performance. The synergistic effect of the two additives can prevent capacity decay caused by the collapse of the positive electrode material structure, reduce side reactions between the electrolyte and the negative electrode material, and reduce the consumption of active lithium, thereby improving the cycle stability of the battery in high temperature and high pressure environments.

[0009] As a preferred technical solution, R1~R 10 Each is independently selected from hydrogen, halogen, substituted or unsubstituted C1-C6 alkyl groups, m is selected from 0 or 1, R 11 ~R 14 Each is independently selected from substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C2-C6 alkenyl, or substituted or unsubstituted C2-C6 alkynyl, and when substituted, the substituent is halogen.

[0010] As a preferred technical solution, the cyclic sulfonic anhydride compound of the present invention is selected from at least one of compounds 1 to 4:

[0011] Compound 1, Compound 2, Compound 3, Compound 4.

[0012] Among them, the CAS of compound 1 is 4720-58-5; the CAS of compound 2 is 1234622-63-9; the CAS of compound 3 is 1562-04-5; and the CAS of compound 4 is 4378-87-4.

[0013] As a preferred technical solution, the sulfonate silicone compound of the present invention is selected from at least one of compounds 5 to 8. Compound 5, Compound 6, Compound 7, Compound 8.

[0014] Among them, the CAS of compound 5 is 1009-05-8; the CAS of compound 6 is 27607-77-8; the CAS of compound 7 is 1220996-42-8; and the CAS of compound 8 is 115827-19-5.

[0015] As a preferred technical solution, the cyclic sulfonic anhydride compound of the present invention has a mass percentage of 0.05% to 5% in the non-aqueous electrolyte. Preferably, the mass percentage of the cyclic sulfonic anhydride compound in the non-aqueous electrolyte is 0.1% to 2%, and more preferably, the mass percentage of the cyclic sulfonic anhydride compound in the non-aqueous electrolyte is 0.1% to 1%. As examples, the mass percentage of the cyclic sulfonic anhydride compound in the non-aqueous electrolyte is 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%, and 5.0%, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0016] As a preferred technical solution, the mass percentage of the sulfonate silicone compound in the non-aqueous electrolyte of the present invention is 0.05% to 5%. Preferably, the mass percentage of the sulfonate silicone compound in the non-aqueous electrolyte is 0.1% to 4%, and more preferably, the mass percentage of the sulfonate silicone compound in the non-aqueous electrolyte is 0.5% to 2%. As examples, the mass percentage of the sulfonate silicone compound in the non-aqueous electrolyte is 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%, and 5.0%, but it is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0017] As a preferred technical solution, 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(oxalateborate)borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium fluorosulfonate (LiSO2F), lithium difluorooxalateborate (LiODFB), lower aliphatic carboxylic acids, lithium difluorodioxalate phosphate (LiDODFP), and lithium bis(fluorosulfonyl)imide (LiFSI).

[0018] As a preferred technical solution, the lithium salt in the non-aqueous electrolyte of the present invention has a mass percentage of 5-25%, further, the lithium salt has a mass percentage of 8-20%, and more preferably, the lithium salt has a mass percentage of 10-15%. As an example, the mass percentage of lithium salt in the non-aqueous electrolyte may be, but is not limited to, 5%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 20%, 22%, 24%, and 25%.

[0019] As a preferred technical solution, the non-aqueous organic solvent of the present invention is selected from at least one of carbonate solvents, carboxylic acid ester solvents, and ether solvents. Specifically, carboxylic acid ester solvents include, but are not limited to, γ-butyrolactone, γ-valerolactone, δ-valerolactone, methyl acetate (MA), ethyl acetate (EA), ethyl propionate (EP), and butyl acetate (n... Ba), propyl propionate (n) At least one of PP and butyl propionate. Carbonate solvents include, but are not limited to, at least one of ethylene carbonate (EC), propylene carbonate, butyl carbonate (BC), amyl carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), methyl n-propyl carbonate, ethyl n-propyl carbonate, and propylene carbonate (PC). Ether solvents include, but are not limited to, at least one of 1,3-dioxolane (DOL), 1,4-dioxane (DX), crown ethers, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH3-THF), 2-trifluoromethyltetrahydrofuran (2-CF3-THF), dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

[0020] As a preferred technical solution, the mass percentage of the organic solvent of the present invention in the non-aqueous electrolyte is 65-90%. Preferably, the mass percentage of the non-aqueous organic solvent in the non-aqueous electrolyte is 75-89%. More preferably, the mass percentage of the non-aqueous organic solvent in the non-aqueous electrolyte is 78-88%. By way of example, the mass percentage of the non-aqueous organic solvent in the non-aqueous electrolyte can be, but is not limited to, 60%, 65%, 75%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 90%.

[0021] As a preferred technical solution, the non-aqueous electrolyte of the present invention further includes an auxiliary agent, and the auxiliary agent is selected from at least one of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propane sultone (PS), divinyl sulfone (DTD), 1,3-propanediol cyclic sulfate (PCS), 1,4-butane sultone, triallyl phosphate (TAP), and succinic anhydride (SA).

[0022] On the other hand, the present invention provides a lithium ion battery, which includes a positive electrode material, a negative electrode material, and also includes the aforementioned non-aqueous electrolyte.

[0023] As a preferred technical solution, the positive electrode material of the present invention is selected from at least one of nickel cobalt manganese oxide and nickel cobalt aluminum oxide. Specifically, the chemical formula of nickel cobalt manganese oxide is LiNi x Co y Mn z M (1-x-y-z) O2, and 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. By way of example, the positive electrode material is lithium nickel cobalt manganese oxide, and its chemical formula is LiNi 0.6 Co 0.2 Mn 0.2 .

[0024] As a preferred technical solution, the negative electrode material of the present invention is selected from at least one of artificial graphite, natural graphite, lithium titanate, silicon-carbon composite material, and silicon monoxide. By way of example, the negative electrode material is artificial graphite, but is not limited thereto. Detailed implementation manners

[0025] To better illustrate the purpose, technical solution, and beneficial effects of this invention, the invention will be further described below with reference to specific embodiments. It should be noted that the methods described below are further explanations of this invention and should not be construed as limiting it.

[0026] Example 1 (1) Preparation of non-aqueous electrolyte In an argon atmosphere and a vacuum glove box with a moisture content of <1ppm, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed at a weight ratio of EC:EMC = 3:7 to obtain 86.8g of non-aqueous organic solvent. Then, 0.2g of compound 1 and 0.5g of compound 5 were added, dissolved, and stirred thoroughly. After that, 12.5g of lithium hexafluorophosphate (LiPF6) was added and mixed evenly to obtain a non-aqueous electrolyte.

[0027] (2) Preparation of positive electrode LiNi nickel cobalt manganese oxide material LiNi 0.6 Co 0.2 Mn 0.2 The binder PVDF and the conductive agent SuperP are mixed evenly at a mass ratio of 96:2.5:1.5 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.

[0028] (3) Preparation of negative electrode A negative electrode graphite material, binder PVDF and conductive agent SuperP are mixed evenly at a mass ratio of 90:2:8 to prepare a lithium secondary battery negative electrode slurry with a certain viscosity. The mixed slurry is coated on both sides of copper foil, dried and rolled to obtain a negative electrode sheet.

[0029] (4) Preparation of lithium-ion batteries The positive electrode, separator, and negative electrode are stacked in sequence, and then layered as needed. After the tabs are welded, they are placed in the aluminum-plastic film of the battery outer packaging. The prepared non-aqueous electrolyte is injected into the dried bare cell. Vacuum sealing, standing, formation (0.05C constant current charging to 3.9V, then 0.1C constant current charging to 4.45V), shaping, and capacity testing are carried out in sequence to finally obtain a 1Ah soft-pack lithium secondary battery.

[0030] The non-aqueous electrolyte formulations of Examples 1-25 and Comparative Examples 1-5 are shown in Table 1. The steps for preparing the electrolyte and manufacturing the battery in Examples 2-25 and Comparative Examples 1-5 are the same as those in Example 1.

[0031] Table 1. Formulations of non-aqueous electrolytes for each example and comparative example.

[0032] The lithium-ion batteries prepared in Examples 1-25 and Comparative Examples 1-5 were subjected to high-temperature storage tests, high-temperature cycle tests, and internal resistance tests, respectively. The specific test conditions are as follows, and the performance test results are shown in Table 2.

[0033] High-Temperature Storage Performance Test of Lithium-ion Batteries Under normal temperature (25℃) conditions, a lithium-ion battery was subjected to one 0.3C / 0.3C charge and discharge cycle (battery discharge capacity recorded as C0), with an upper limit voltage of 4.45V. Then, the battery was charged to 4.45V under constant current and constant voltage conditions at 0.5C, and the battery thickness was measured (thickness recorded as D0). The battery was placed in a 60℃ oven for 30 days, removed, and its thickness measured (thickness recorded as D1). The battery was then placed in a 25℃ environment and discharged at 0.3C, with the discharge capacity recorded as C1. Finally, the lithium-ion battery was subjected to one 0.3C / 0.3C charge and discharge cycle (battery discharge capacity recorded as C2), with an upper limit voltage of 4.45V. The capacity retention rate, capacity recovery rate, and thickness expansion rate of the lithium-ion battery were calculated using the following formulas: Capacity retention rate = (C1 / C0) × 100% Capacity recovery rate = (C2 / C0) × 100% Thickness expansion rate = (D1 / D2) × 100% High-temperature cycle performance test of lithium-ion batteries The lithium-ion battery was placed in a 45°C constant temperature chamber and left to stand for 30 minutes to reach a constant temperature. It was then charged at a constant current of 4C until the voltage reached 4.45V, followed by constant voltage charging at 4.45V until the current reached 0.05C. Next, it was discharged at a constant current of 4C until the voltage reached 2.5V. The first discharge capacity was recorded as C0, constituting one charge-discharge cycle. Then, 1000 cycles of 1C / 1C charge and discharge were performed at 45°C, with the discharge capacity recorded as C1. The capacity retention rate of the lithium-ion battery was calculated using the following formula: Capacity retention rate = (C1 / C0) × 100% Internal resistance test After capacity testing, the lithium-ion batteries were placed in a 25°C constant temperature chamber and left to stand for 30 minutes to allow them to reach a constant temperature. They were then charged at a constant current of 1C until the voltage reached 4.45V, followed by constant voltage charging at 4.45V until the current reached 0.05C. Next, they were discharged at a constant current of 1C until the voltage reached 3V. The first discharge capacity of the battery was recorded as C0. This constitutes one charge-discharge cycle. Then, three cycles of 1C / 1C charging and discharging were performed at 25°C. The battery was discharged to 0.5C0, and its DC internal resistance R was measured.

[0034] Acid value test of non-aqueous electrolyte Refer to SJ / T11723 In the 2018 lithium-ion battery electrolyte, step 4.5.1 was performed. After the potentiometric titrator was calibrated, 10.00 g of electrolyte sample was accurately weighed and added to 50 mL of anhydrous ethanol. Titration was performed with a 0.01 mol / L weak organic base, and the titration volume was recorded. The instrument automatically calculated the free acid content (calculated as HF) in the electrolyte. The results are shown in Table 3.

[0035] Table 2 Performance test results of lithium-ion batteries in each embodiment and comparative example

[0036] Table 3. Acid value test results of non-aqueous electrolytes before and after high-temperature cycling in each example and comparative example.

[0037] See Tables 2 and 3 for the performance test results. As shown in Examples 1-25 and Comparative Examples 1-5, the non-aqueous electrolyte of the present invention has a more stable acid value. Furthermore, lithium-ion batteries using this non-aqueous electrolyte exhibit superior high-temperature storage and high-temperature cycling performance, and lower internal resistance. This may be because the non-aqueous electrolyte of the present invention includes at least one cyclic sulfonic anhydride compound selected from structural formulas I and II, and a sulfonate silicon ester compound selected from structural formula III. The cyclic sulfonic anhydride compound can preferentially undergo reduction and decomposition on the negative electrode surface to form a stable SEI film, effectively reducing side reactions between the electrolyte and the negative electrode material and improving the structural stability of the negative electrode material. However, its unsaturated cyclic structure is prone to ring-opening polymerization or decomposition at high temperatures, generating high molecular weight products, increasing electrolyte viscosity, reducing ion migration rate, and potentially covering electrode active sites, thus deteriorating high-temperature cycling performance. Therefore, this invention introduces sulfonate silicate compounds, as shown in Formula II, into the non-aqueous electrolyte to synergistically regulate the composition of the solid electrolyte membrane. These compounds can reduce electrolyte decomposition and gas production at high temperatures and inhibit the increase in water content and acid value within the battery, thereby improving the battery's room-temperature cycling and high-temperature storage performance. The synergistic effect of the two additives can prevent capacity decay caused by the collapse of the positive electrode material structure, reduce side reactions between the electrolyte and the negative electrode material, and decrease the consumption of active lithium, thus improving the battery's cycle stability.

[0038] The test results from Examples 1-16 show that the electrolyte exhibits superior performance when it contains compound 6 or compound 8. This may be because compound 6 or compound 8 contains both fluorine and sulfonic acid groups in its structure, which can produce electrolytes rich in LiF and Li2SO4. x A homogeneous and mechanically stable CEI. LiF-rich CEI can suppress the degradation of NCM622 cathodes and the growth of lithium dendrites. Meanwhile, Li₂SO₄, with its high ionic conductivity...x The component promoted the Li in CEI + Furthermore, trimethylsilyl methanesulfonate compounds can remove HF from the electrolyte and effectively inhibit the corrosion of HF on the CEI and NCM622 cathodes. Therefore, the synergistic effect of the two additives endows the electrolyte with higher thermal stability and antioxidant capacity, delaying the decomposition of the electrolyte under high voltage / high temperature, thereby improving the high-temperature cycling and high-temperature storage performance of ternary lithium-ion batteries.

[0039] As shown in Comparative Examples 2-5, when only cyclic sulfonic anhydride compounds or sulfonate silicon ester compounds are used, the high-temperature storage and cycle performance of lithium-ion batteries cannot be simultaneously improved, and the improvement effect is lower than that of the examples. This further demonstrates that the synergistic effect of cyclic sulfonic anhydride compounds and sulfonate silicon ester compounds can improve the ion transport rate of lithium-ion batteries, form a stable SEI film, reduce battery internal resistance, and improve the high-temperature storage and high-temperature cycle performance of lithium-ion batteries.

[0040] 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, comprising a lithium salt, a non-aqueous organic solvent, and additives, characterized in that, The additive includes at least one cyclic sulfonic anhydride compound selected from those shown in structural formula I and structural formula II. Structural Formula I Structural Formula II And, sulfonate silicate compounds represented by structural formula III, Structural Form III Among them, R1~R 14 Each is independently selected from hydrogen, halogen, substituted or unsubstituted C1~C6 alkyl, substituted or unsubstituted C2~C6 alkenyl, substituted or unsubstituted C2~C6 alkynyl, and m is selected from 0 or 1.

2. The non-aqueous electrolyte according to claim 1, characterized in that, R1~R 10 Each is independently selected from hydrogen, halogen, substituted or unsubstituted C1-C6 alkyl groups, m is selected from 0 or 1, R 11 ~R 14 Each is independently selected from substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C2-C6 alkenyl, or substituted or unsubstituted C2-C6 alkynyl, and when substituted, the substituent is halogen.

3. The non-aqueous electrolyte according to claim 1, characterized in that, The cyclic sulfonic anhydride compound is selected from at least one of compounds 1 to 4: Compound 1, Compound 2, Compound 3, Compound 4.

4. The non-aqueous electrolyte according to claim 1, characterized in that, The sulfonate silicate compound is selected from at least one of compounds 5 to 8. Compound 5, Compound 6, Compound 7, Compound 8.

5. The non-aqueous electrolyte according to claim 1, characterized in that, The cyclic sulfonic anhydride compound has a mass percentage of 0.05% to 5% in the non-aqueous electrolyte, and the sulfonate silicone compound has a mass percentage of 0.05% to 5% in the non-aqueous electrolyte.

6. The non-aqueous electrolyte according to claim 5, characterized in that, The cyclic sulfonic anhydride compound has a mass percentage of 0.1% to 2% in the non-aqueous electrolyte, and the sulfonate silicone compound has a mass percentage of 0.1% to 4% in the non-aqueous electrolyte.

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 bis(trifluoromethanesulfonyl)imide, lithium bis(oxalate-borate), lithium difluorophosphate, lithium fluorosulfonate, lithium difluorooxalate-borate, lithium lower aliphatic carboxylic acids, lithium difluorodioxalate phosphate, and lithium bis(oxalate-imide).

8. The non-aqueous electrolyte according to claim 1, characterized in that, The non-aqueous organic solvent is selected from at least one of carbonate solvents, carboxylic acid ester solvents, and ether solvents.

9. A lithium-ion battery, comprising a positive electrode material and a negative electrode material, characterized in that, It also includes the non-aqueous electrolyte as described in any one of claims 1 to 7.

10. The lithium-ion battery according to claim 9, characterized in that, The cathode material is selected from at least one of nickel cobalt manganese oxide and nickel cobalt aluminum oxide.

Images