Nonaqueous electrolyte and secondary battery comprising same

Abstract

The invention provides a non-aqueous electrolyte and a secondary battery containing the non-aqueous electrolyte. The non-aqueous electrolyte comprises an electrolyte salt, a non-aqueous organic solvent and an additive. The additive comprises a sulfonyl pyridinium inner salt compound and a sulfonyl fluoride compound. The structural formula of the sulfonyl pyridinium inner salt compound is as shown in the structural formula I. The structural formula of the fluorosulfonyl compound is shown as a structural formula II or a structural formula III. Wherein R < 1 > to R < 6 > are independently selected from hydrogen atoms and substituted or unsubstituted alkyl groups of C1 to C3, R < 7 > to R < 8 > are independently selected from hydrogen atoms and substituted or unsubstituted alkyl groups of C1 to C3, and R < 9 > is selected from alkylene groups of C1 to C10. The additive of the non-aqueous electrolyte contains a sulfonyl pyridinium inner salt compound and a sulfonyl fluoride compound, so that the high-temperature cycle performance can be improved while the high-temperature storage performance of the battery is improved. # imgabs0 #

Description

Technical Field

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

[0002] Although lithium-ion batteries have certain advantages in replacing traditional batteries as power sources for electric vehicles, hybrid electric vehicles, electric bicycles and electric tools, when lithium-ion batteries are abused or misused, such as when used at high temperatures or when the charger control fails, violent chemical reactions may occur inside the battery, generating a large amount of heat. If the heat does not dissipate in time and quickly accumulates inside the battery, the battery may leak, release gas, smoke, etc. In severe cases, the battery may burn violently and explode, causing certain harm to the life safety or property interests of the consumer group, thus seriously hindering the large-scale development of lithium-ion batteries. Therefore, the key to the successful large-scale development of lithium-ion batteries is whether the safety of lithium-ion batteries can be fundamentally improved. The safety research of lithium-ion batteries mainly focuses on the cycle and storage performance at high temperatures.

[0003] At high temperatures, the positive and negative active materials show high activity in the electrolyte. In order to ensure the safe use of the battery, the industry currently uses positive electrode materials with high thermal stability to solve the problem of thermal decomposition of high-temperature positive electrode materials. However, the process of synthesizing highly thermally stable positive electrode materials is complex and the price is not cheap, which is not conducive to the promotion and use of lithium-ion batteries at high temperatures.

[0004] At present, the industry also adds high-temperature additives to the electrolyte to improve the high-temperature performance by forming a stable SEI film during the battery charging and discharging process. However, although the current high-temperature additives can form a stable SEI film to improve the high-temperature stability of the battery, the film layer is relatively thick, which is not conducive to high-temperature cycle performance, that is, it is difficult to take into account both high-temperature cycle and high-temperature storage performance at the same time. Summary of the invention

[0005] In view of the above problems, the object of the present invention is to provide a non-aqueous electrolyte and a secondary battery comprising the non-aqueous electrolyte, wherein the additives in the non-aqueous electrolyte contain sulfonic acid pyridinium salt compounds and fluorosulfonyl compounds, which can improve the high-temperature storage performance of the battery while improving the high-temperature cycle performance.

[0006] In order to achieve the above objectives, the present invention provides a non-aqueous electrolyte, including an electrolyte salt, a non-aqueous organic solvent and an additive. The additive includes a sulfonic acid pyridinium inner salt compound and a fluorosulfonyl compound, the structural formula of the sulfonic acid pyridinium inner salt compound is shown in Structural Formula I, the structural formula of the fluorosulfonyl compound is shown in Structural Formula II or Structural Formula III, wherein R1 to R6 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1 to C3 hydrocarbon group, R7 to R8 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1 to C3 hydrocarbon group, and R9 is selected from C1 to C 10 of alkylene.

[0007]

[0008] Compared with the prior art, the additives of the non-aqueous electrolyte of the present invention include a sulfonic acid pyridinium inner salt compound as shown in structural formula I and a fluorosulfonyl compound as shown in structural formula II or structural formula III. As a zwitterionic compound, the sulfonic acid pyridinium inner salt compound can effectively accelerate the lithium ion transmission rate and improve the rate fast charging performance of the secondary battery. The sulfonic acid group contained therein can form a film at the negative electrode to improve the high temperature storage performance of the secondary battery. But at the same time, the SEI film formed by the sulfonic acid group at the negative electrode will increase the internal resistance of the secondary battery, and the pyridinium group is also easy to react with lithium metal, affecting the stability of the SEI film. Therefore, the present invention introduces a fluorosulfonyl compound as shown in structural formula II or structural formula III into the non-aqueous electrolyte, which synergistically regulates the constituent components of the solid electrolyte membrane, increases the content of inorganic components such as lithium fluoride, etc., to reduce the internal resistance of the secondary battery, thereby improving the cycle performance at high temperature. Therefore, the present invention can increase the lithium ion transfer rate of the secondary battery and reduce the internal resistance of the battery by combining the sulfonic acid pyridinium salt compound shown in structural formula I and the fluorosulfonyl compound shown in structural formula II or structural formula III, thereby improving the high-temperature storage performance and high-temperature cycle performance of the secondary battery.

[0009] As a technical solution of the present invention, R1-R6 are each independently selected from hydrogen atom, methyl, ethyl or vinyl, R7-R8 are each independently selected from methyl, ethyl or vinyl, and R9 is selected from C2 to C6 alkylene.

[0010] As a technical solution of the present invention, based on the sum of the mass of the electrolyte salt, the non-aqueous organic solvent and the additive as 100%, the mass proportion of the sulfonic acid pyridinium inner salt compound is 0.05-5.00%, and the mass proportion of the fluorosulfonyl compound is 0.05-5.00%.

[0011] As a technical solution of the present invention, the mass proportion of the sulfonic acid pyridinium inner salt compound is 0.10-2.00%, and the mass proportion of the fluorosulfonyl compound is 0.10-2.00%.

[0012] As a technical solution of the present invention, the sulfonic acid pyridinium salt compound is at least one selected from Compound 1 to Compound 5.

[0013]

[0014]

[0015] As a technical solution of the present invention, the fluorosulfonyl compound is selected from at least one of Compound 6 to Compound 10.

[0016]

[0017] As a technical solution of the present invention, the electrolyte salt is selected from at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonyl imide), lithium bis(oxalatoborate), lithium difluorophosphate, lithium fluorosulfonate, lithium difluorooxalatoborate, lithium lower aliphatic carboxylate, lithium difluorobis(oxalatophosphate) and lithium bis(fluorosulfonyl imide).

[0018] As a technical solution of the present invention, 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, pentyl carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl 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.

[0019] The second aspect of the present invention provides a secondary battery, comprising a positive electrode material, a negative electrode material and the aforementioned non-aqueous electrolyte. The secondary battery contains the non-aqueous electrolyte and has good high-temperature storage performance and high-temperature cycle performance.

[0020] As a technical solution of the present invention, the positive electrode material is selected from at least one of nickel cobalt manganese oxide, lithium cobaltate or nickel cobalt aluminum oxide. DETAILED DESCRIPTION

[0021] The present invention mainly provides a non-aqueous electrolyte, which can be used in lithium-ion batteries, sodium-ion batteries, etc., and is preferably used in lithium-ion batteries. Of course, in addition to the non-aqueous electrolyte, a lithium-ion battery may also include a positive electrode material and a negative electrode material.

[0022] The positive electrode material may be at least one of a metal oxide and a polyanion-type compound. Specifically, the metal oxide includes a lithium cobalt oxide material, a lithium iron phosphate material, a nickel cobalt manganese oxide, or a nickel cobalt aluminum oxide. The lithium cobalt oxide material is lithium cobalt oxide or lithium cobalt oxide modified by doping and coating. The lithium iron phosphate material is lithium iron phosphate or lithium iron phosphate modified by doping and coating. The chemical formula of the nickel cobalt manganese oxide is LiNi x Co y Mn z M (1-x-y-z) O2, and the chemical formula of the 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 chemical formula of the polyanion-type compound is Li x N y (XO z ) n , where N is independently selected from at least one of Fe, Mn, Ni, Cu, and V, X is independently selected from one of S, P, Si, Mo, and As, 1 ≤ x ≤ 4, 1 ≤ y ≤ 3, 1 ≤ n ≤ 3, and 1 ≤ z ≤ 4. For another example, the positive electrode material is lithium iron phosphate, and its chemical formula is LiFePO4.

[0023] The negative electrode material includes a carbon-based material, a silicon-based material, a tin-based material, or a lithium titanate material. The carbon-based material may be artificial graphite, natural graphite, soft carbon, hard carbon, graphene, etc. The silicon-based material includes elemental silicon, silicon oxide compounds, silicon carbide compounds, silicon alloy materials, etc. The tin-based material includes elemental tin, tin oxide compounds, tin carbide compounds, tin alloy materials, etc.

[0024] The non-aqueous electrolyte of the present invention includes a non-aqueous organic solvent, an electrolyte salt, and an additive. It includes a sulfonic acid group pyridinium inner salt compound and a fluorosulfonyl compound. The structural formula of the sulfonic acid group pyridinium inner salt compound is as shown in Structural Formula I, and the structural formula of the fluorosulfonyl compound is as shown in Structural Formula II or Structural Formula III. Among them, R1 to R6 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1 to C3 hydrocarbon group, R7 to R8 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1 to C3 hydrocarbon group, and R9 is selected from C1 to C10 of alkylene.

[0025]

[0026] Further, R1 to R6 are each independently selected from a hydrogen atom, a methyl group, an ethyl group or a vinyl group, R7 to R8 are each independently selected from a methyl group, an ethyl group or a vinyl group, and R9 is selected from an alkylene group of C2 to C6. Further, the halogen atom is fluorine, and the halogen substitution is fluorine substitution. As an example, R1 to R6 are each independently selected from a hydrogen atom, a fluorine atom, a methane group, an ethyl group, a propane group, an isopropane group, a butane group, a pentane group, a pentyl group, a vinyl group, a propenyl group, an isopropenyl group, a butenyl group, a pentenyl group, a pentenyl group, an ethynyl group, a propynyl group, an isopropynyl group, a butynyl group, a pentynyl group, a pentynyl group, a monofluoro-substituted or polyfluoro-substituted methane group, a monofluoro-substituted or polyfluoro-substituted ethyl group, a monofluoro-substituted or polyfluoro-substituted propane group, a monofluoro-substituted or polyfluoro-substituted isopropane group, a monofluoro-substituted or polyfluoro-substituted butane group, a monofluoro-substituted or polyfluoro-substituted pentane group The invention further comprises the following: alkyl, monofluorinated or polyfluorinated substituted pentyl, monofluorinated or polyfluorinated substituted vinyl, monofluorinated or polyfluorinated substituted propenyl, monofluorinated or polyfluorinated isopropenyl, monofluorinated or polyfluorinated substituted butenyl, monofluorinated or polyfluorinated substituted pentenyl, monofluorinated or polyfluorinated substituted hexenyl, monofluorinated or polyfluorinated substituted ethynyl, monofluorinated or polyfluorinated substituted propynyl, monofluorinated or polyfluorinated substituted isopropynyl, monofluorinated or polyfluorinated substituted butynyl, monofluorinated or polyfluorinated substituted pentynyl, and pentyl- or polyfluorinated substituted alkynyl. R7 to R8 are each independently selected from a hydrogen atom, a fluorine atom, a methyl group, an ethyl group, a propanyl group, an isopropyl group, a butanyl group, a pentyl group, a pentyl group, a vinyl group, an isopropyl group, a butenyl group, a pentenyl group, a pentyl group, an ethynyl group, a propynyl group, an isopropynyl group, a butynyl group, a pentynyl group, a pentynyl group, a monofluorinated or polyfluorinated methyl group, a monofluorinated or polyfluorinated ethyl group, a monofluorinated or polyfluorinated propanyl group, a monofluorinated or polyfluorinated isopropyl group, a monofluorinated or polyfluorinated butanyl group, a monofluorinated or polyfluorinated pentyl group, R9 is selected from the group consisting of methylene, ethylene, propylene, isopropylene, butylene, pentyl, pentylene.

[0027] The sulfonic acid pyridinium inner salt compound is selected from at least one of compound 1 to compound 5. Taking the sum of the mass of the electrolyte salt, the non-aqueous organic solvent and the additive as 100%, the mass proportion of the sulfonic acid pyridinium inner salt compound is 0.05-5.00%, preferably, the mass proportion of the sulfonic acid pyridinium inner salt compound is 0.10-2.00%. As an example, the mass proportion of the sulfonic acid pyridinium inner salt compound can be, but is not limited to, 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, 5.00%.

[0028]

[0029] The fluorosulfonyl compound is selected from at least one of compound 6 to compound 10. Taking the sum of the mass of the electrolyte salt, the non-aqueous organic solvent and the additive as 100%, the mass proportion of the fluorosulfonyl compound is 0.05-5.00%, preferably, the mass proportion of the fluorosulfonyl compound is 0.10-2.00%. As an example, the mass proportion of the fluorosulfonyl compound can be, but is not limited to, 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, 5.00%.

[0030]

[0031] The electrolyte 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 bistrifluoromethanesulfonyl imide (LiTFSI), lithium bisoxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium fluorosulfonate (LiSO2F), lithium bisoxalate borate (C4BLiO8), lithium difluorooxalate borate, lower aliphatic lithium carboxylate, lithium difluorobisoxalate phosphate and lithium bisfluorosulfonyl imide. Further, lower aliphatic lithium carboxylate includes but is not limited to lithium chloroborane, lithium tetraphenylborate, lithium imide salts, etc. As an example, the electrolyte salt is lithium hexafluorophosphate (LiPF6), but is not limited thereto. Further, the electrolyte salt is a mixture of lithium hexafluorophosphate and lithium bisoxalate borate, but is not limited thereto. The mass percentage of the electrolyte salt in the non-aqueous electrolyte of the present invention is 5-25%. Further, the mass percentage of the electrolyte salt in the non-aqueous electrolyte is 8-20%. More preferably, the mass percentage of the electrolyte salt in the non-aqueous electrolyte is 10-15%. By way of example, the mass percentage of the electrolyte salt in the non-aqueous electrolyte may 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%, 25%.

[0032] The non-aqueous organic solvent of the present invention 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, pentylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl 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. The mass percentage of the non-aqueous organic solvent in the non-aqueous electrolyte of the present invention 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%. As an example, the mass percentage of the non-aqueous organic solvent in the non-aqueous electrolyte can be, but is not limited to, 65%, 67%, 69%, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 90%.

[0033] In order to better illustrate the purpose, technical scheme and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of the present invention and should not be used as a limitation of the present invention.

[0034] Where specific conditions are not specified in the examples, the experiments can be carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without specifying the manufacturer are all conventional products available from the market.

[0035] Example 1

[0036] (1) Preparation of non-aqueous electrolyte

[0037] In an argon atmosphere, in a vacuum glove box with a moisture content of <1ppm, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a weight ratio of EC:EMC=3:7, and then various additives are added. After dissolving and stirring thoroughly, LiPF6 is added and mixed evenly to obtain a non-aqueous electrolyte.

[0038] (2) Preparation of positive electrode

[0039] The lithium iron phosphate material LiFePO4, the adhesive PVDF and the conductive agent SuperP are mixed evenly in 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 an aluminum foil, and then dried and rolled to obtain a positive electrode sheet.

[0040] (3) Preparation of negative electrode

[0041] The negative electrode graphite material, the adhesive PVDF and the conductive agent SuperP are mixed evenly in 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 a copper foil, and then dried and rolled to obtain a negative electrode sheet.

[0042] (4) Preparation of secondary batteries

[0043] The positive electrode sheet, the separator, and the negative electrode sheet are stacked in order, and then stacked as needed. After the tabs are welded, they are placed in the aluminum plastic film of the battery outer packaging, and the prepared non-aqueous electrolyte is injected into the dried bare battery cell, and vacuum packaging, static, formation (0.05C constant current charging to 3.0V, and then 0.1C constant current charging to 3.3V), shaping, capacity testing and other processes are carried out successively, and finally a 1Ah soft-pack lithium secondary battery is obtained.

[0044] The non-aqueous electrolyte formulations of Examples 2 to 18 and Comparative Examples 1 to 3 are shown in Table 1. The steps of preparing the electrolyte and preparing the battery are the same as those of Example 1.

[0045] Table 1 Formulas of non-aqueous electrolytes of Examples 2 to 18 and Comparative Examples 1 to 3

[0046]

[0047]

[0048] The secondary batteries prepared in Examples 1 to 18 and Comparative Examples 1 to 3 were subjected to high temperature storage test and high temperature cycle test respectively. The specific test conditions are as follows. The performance test results are shown in Table 2.

[0049] (1) High temperature storage performance test

[0050] At room temperature (25°C), the secondary battery is charged and discharged at 0.3C / 0.3C (the battery discharge capacity is recorded as C0), the upper limit voltage is 3.65V, the battery is placed in a 60°C oven for 30 days, the battery is taken out, the battery is placed in a 25°C environment, and discharged at 0.3C, and the discharge capacity is recorded as C1. Then the secondary battery is charged and discharged at 0.3C / 0.3C (the battery discharge capacity is recorded as C2), and the capacity retention rate and capacity recovery rate of the secondary battery under high temperature storage are calculated using the following formula.

[0051] Capacity retention rate = (C1 / C0) × 100%

[0052] Capacity recovery rate = (C2 / C0) × 100%

[0053] (2) High temperature cycle performance test

[0054] Place the secondary battery in a 45℃ constant temperature box and let it stand for 30 minutes to make the secondary battery reach a constant temperature. Charge it at a constant current of 4C to a voltage of 3.65V, then charge it at a constant voltage of 3.65V to a current of 0.05C, and then discharge it at a constant current of 4C to a voltage of 2.5V. Record the first discharge capacity of the battery as C0, which is a charge and discharge cycle. Then, charge and discharge it at 1C / 1C for 1000 cycles at 45℃, record the discharge capacity as C1, and use the following formula to calculate the capacity retention rate of the secondary battery under high temperature cycling.

[0055] Capacity retention rate = (C1 / C0) × 100%

[0056] Table 2 Performance test results of secondary batteries

[0057]

[0058]

[0059] From the results in Table 2, it can be seen that the electrolyte of the present invention can simultaneously improve the high-temperature storage performance and high-temperature cycle performance of the secondary battery by combining the sulfonic acid pyridinium salt compound shown in structural formula I and the fluorosulfonyl compound shown in structural formula II or structural formula III. When the contents of the sulfonic acid pyridinium salt compound shown in structural formula I and the fluorosulfonyl compound shown in structural formula II or structural formula III are both less than or equal to 2%, the two can achieve a better combination effect.

[0060] From the comparison of Examples 1 to 5, it can be seen that when the sulfonic acid pyridinium salt compound is compound 1, the alkalinity of pyridine N is concentrated, the stability of the acid value in the electrolyte is enhanced, and the damage of the acid value to the electrolyte interface film is reduced, thereby improving the probability of electrons passing through the interface film and improving the high-temperature cycle and high-temperature storage performance.

[0061] By comparing Example 1 with Examples 6 to 9, it can be seen that when the fluorosulfonyl compound is Compound 6, the high-temperature storage performance and high-temperature cycle performance are better. This is because for the methyl-substituted fluorosulfonyl substance, the alkyl substituent is an electron-donating group. The longer the alkyl chain and the greater the number of alkyl chains, the easier it is for the fluorine in the fluorosulfonyl group to leave, increasing the acidity of the electrolyte and causing a decrease in battery performance. Because the methyl substituents at both ends make the electrolyte interface stable, the battery has the best high-temperature cycle and high-temperature storage performance.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A non-aqueous electrolyte comprising an electrolyte salt, a non-aqueous organic solvent and an additive, characterized in that: The additive comprises a sulfonic acid pyridinium inner salt compound and a fluorosulfonyl compound, wherein the structural formula of the sulfonic acid pyridinium inner salt compound is as shown in structural formula I, and the structural formula of the fluorosulfonyl compound is as shown in structural formula II or structural formula III. wherein R1-R6 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1 to C3 hydrocarbon group, R7-R8 are each independently selected from a hydrogen atom, a substituted or unsubstituted C1 to C3 hydrocarbon group, and R9 is selected from a C1 to C 10 of alkylene.

2. The non-aqueous electrolyte according to claim 1, characterized in that ,, R1~R6 are each independently selected from a hydrogen atom, a methyl group, an ethyl group or a vinyl group, R7~R8 are each independently selected from a methyl group, an ethyl group or a vinyl group, and R9 is selected from an alkylene group from C2 to C6.

3. The non-aqueous electrolyte according to claim 1, characterized in that Based on the sum of the mass of the electrolyte salt, the non-aqueous organic solvent and the additive as 100%, the mass of the sulfonic acid pyridinium inner salt compound accounts for 0.05 to 5.00%, and the mass of the fluorosulfonyl compound accounts for 0.05 to 5.00%.

4. The non-aqueous electrolyte according to claim 3, characterized in that The mass proportion of the sulfonic acid pyridinium inner salt compound is 0.10-2.00%, and the mass proportion of the fluorosulfonyl compound is 0.10-2.00%.

5. The non-aqueous electrolyte according to claim 1, characterized in that The sulfonic acid pyridinium salt compound is at least one selected from Compound 1 to Compound 5, 6. The non-aqueous electrolyte according to claim 1, characterized in that The fluorosulfonyl compound is selected from at least one of Compound 6 to Compound 10, 7. The non-aqueous electrolyte according to claim 1, characterized in that The electrolyte salt is selected from at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, lithium bistrifluoromethanesulfonyl imide, lithium bisoxalatoborate, lithium difluorophosphate, lithium fluorosulfonate, lithium difluorooxalatoborate, lithium lower aliphatic carboxylate, lithium difluorobisoxalatophosphate and lithium bisfluorosulfonyl 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 methyl acetate, ethyl acetate, ethyl propionate, butyl acetate, propyl propionate, butyl propionate, ethylene carbonate, propylene carbonate, butylene carbonate, pentyl carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl 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 secondary battery, characterized in that: The invention comprises a positive electrode material, a negative electrode material and the non-aqueous electrolyte according to any one of claims 1 to 8.

10. The secondary battery according to claim 9, characterized in that: The positive electrode material is selected from at least one of nickel cobalt manganese oxide, lithium cobaltate or nickel cobalt aluminum oxide.

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