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, wherein the additive comprises a disulfonamide compound as shown in a structural formula 1 or a structural formula 2. The non-aqueous electrolyte provided by the invention contains the disulfonamide compound, so that the high voltage resistance and high temperature resistance of the battery can be effectively improved, and the non-aqueous electrolyte has excellent cycle performance, high-temperature storage performance and safety performance under high voltage. Structural formula 1 and structural formula 2

Description

Technical Field

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

[0002] Lithium-ion batteries, with their high energy density, long cycle life, and low self-discharge rate, have become the core of modern electrochemical energy storage systems. In the power sector, the global electric vehicle market is experiencing explosive growth, with China's new energy vehicle sales expected to exceed 10 million units in 2024, placing higher demands on the energy density of power batteries. Ternary cathode materials (LiNi) are crucial for this development. x CoyMnzO2 and its aluminum-doped variant NCA, with their system-level energy density of 250-300 Wh / kg, have become a key pathway to achieving driving ranges of over 600 kilometers. In the energy storage sector, with the significant increase in wind and solar power capacity, lithium-ion battery energy storage systems play a crucial role in grid frequency regulation, peak shaving and valley filling, and distributed microgrids. In 2023, lithium-ion battery energy storage accounted for over 97% of China's cumulative installed capacity of new energy storage, with ternary systems expanding their share in commercial and industrial energy storage and residential photovoltaic-storage integrated projects due to their higher volumetric energy density and rate performance. In the consumer electronics sector, 5G devices, high-end laptops, and AR / VR wearable devices are placing more stringent demands on battery volumetric energy density and fast charging capabilities, with operating voltages generally increasing from 4.2V to 4.45V or even 4.5V, driving the development of cathode materials towards higher voltage and higher nickel content.

[0003] To improve energy density, the industry is constantly pushing the upper limit of battery operating voltage. Conventional ternary materials operate at >4.3V (vs. Li / Li). + When the lattice oxygen begins to participate in charge compensation, it leads to the precipitation of lattice oxygen and triggers the following chain of problems: (1) Instability of the positive electrode-electrolyte interface (CEI): Under high voltage (≥4.5V), carbonate solvents (such as EC, DMC) and lithium salts (such as LiPF6) will undergo oxidative decomposition, generating a thick and uneven CEI layer. At the same time, the dissolution of transition metals (Ni, Co) is accompanied by the dissolution of metal ions. The dissolved metal ions migrate to the surface of the negative electrode and destroy the SEI, causing the battery impedance to rise continuously and the capacity to decay rapidly; (2) Deterioration of the negative electrode interface kinetics: In the high voltage system, the negative electrode potential is lower, the lithium deposition overpotential increases, and it is easy to trigger the formation of lithium dendrites; at the same time, the metal ions dissolved from the positive electrode are reduced and deposited on the surface of the negative electrode, further catalyzing the reduction of the electrolyte, consuming active lithium, and reducing the coulombic efficiency and cycle life; (3) Electrolyte oxidation and gas side reaction: Under high voltage, solvent molecules (especially ethylene carbonate EC) undergo nucleophilic oxidation on the surface of the positive electrode, generating gases such as CO2 and CO, which leads to battery expansion and increased internal pressure, threatening the sealing safety.

[0004] Meanwhile, safety risks remain a key bottleneck restricting large-scale application. During thermal runaway, ternary materials release oxygen, which reacts violently with the organic electrolyte, triggering a chain reaction of thermal runaway: In power battery systems, a short circuit within a single cell can cause temperatures to exceed 800°C within tens of seconds, and through module-level thermal diffusion, can cause the entire battery pack to burn or even explode. In energy storage scenarios, battery packs are large in scale and have high series and parallel complexity. If localized thermal runaway is not suppressed in time, it can spread through heat conduction, jet flames, and other means, causing catastrophic accidents. Currently, the industry commonly uses phosphate ester flame retardants (such as TEP and DMMP) or fluorinated solvents (such as FEC and FEMC) to improve the intrinsic safety of electrolytes. However, these additives often have significant shortcomings in the following aspects: Although phosphate esters have good flame retardant effects, they have high viscosity and low dielectric constant, which seriously reduces ionic conductivity. Furthermore, they are easily oxidized to form acidic substances under high voltage, which corrodes the electrodes. Fluorinated solvents (such as FEC) can form a LiF-rich SEI at the negative electrode, but their oxidation stability is poor (<4.3V), and they decompose prematurely on the surface of the positive electrode at high voltage, which exacerbates the increase in interfacial impedance.

[0005] Current mainstream improvement strategies include: High-voltage electrolyte formulation: using solvents with high oxidation stability such as sulfonates, sulfones, and nitriles, but their reduction stability is poor and their compatibility with graphite anodes is poor, so they must be used in conjunction with film-forming additives; Solid-state / semi-solid-state batteries: using polymer / inorganic solid electrolytes to improve safety, but facing industrialization challenges such as poor interface contact, low room temperature ionic conductivity, and high cost; Multilayer composite electrode and coating technology: suppressing the contact between the positive electrode and the electrolyte through surface coating (such as Al2O3, LiZr2(PO4)3), but the coating layer may hinder lithium-ion diffusion and reduce rate performance.

[0006] To better address the challenges of high voltage, high safety, and balanced battery performance, patent CN105830272A discloses sulfonate additives containing carbonate structures, which can improve the cycle capacity retention and low-temperature resistance characteristics of non-aqueous electrolyte secondary batteries. However, because the carbonate structures on both sides are easily oxidized at high voltages, producing gases such as CO2 and CO, they are not suitable for high-voltage systems. Patent CN119920988A discloses a disulfonyl additive compound, further enhancing the film-forming function of the additive. However, sulfate / phosphate esters lack coordination sites, and ion conduction relies on the self-polymerization of the matrix itself. The sulfate / phosphate esters on both sides cannot promote the self-assembly of molecules at the electrode / electrolyte interface, resulting in low polymerization efficiency and low degree of polymerization. Consequently, the poor stability of the SEI at high voltages (≥4.5V) becomes apparent. In addition, although phosphate esters are flame-retardant, the thermal stability of the film-forming products is low, thus posing a challenge to the battery's safety performance.

[0007] Therefore, there is an urgent need for a non-aqueous electrolyte and its lithium-ion battery to address the shortcomings of existing technologies. Summary of the Invention

[0008] In view of the above problems, the purpose of this invention is to provide a non-aqueous electrolyte and its lithium-ion battery. The non-aqueous electrolyte contains disulfonamide compounds, which can effectively improve the battery's high voltage and high temperature resistance characteristics, and has excellent cycle performance, high temperature storage performance and safety performance under high voltage.

[0009] To achieve the above objectives, the present invention provides a non-aqueous electrolyte comprising a lithium salt, a non-aqueous organic solvent, and additives, wherein the additives include disulfonamide compounds having structural formula 1 or structural formula 2.

[0010] Wherein, R is selected from halogen or , * indicates the connection end, and n is an integer selected from 1 to 5.

[0011] Compared with the prior art, the non-aqueous electrolyte of the present invention contains disulfonylimide compounds represented by structural formula 1 or structural formula 2. The pyridine ring structure or thiadiazine ring structure in the molecule contains lone pairs of electrons, which can react with Li... + Coordination promotes molecular self-assembly and in-situ polymerization at the electrode / electrolyte interface. Flexible S-(CH2CH2) n Under reducing conditions, the -S segments break and recombine via SC bonds to form a three-dimensional network structure, enhancing the mechanical strength and ionic conductivity of the membrane. Especially at extremely high voltages (≥4.5V), this three-dimensional network structure possesses inherent high-voltage resistance, making the SEI membrane less prone to decomposition and damage under high voltage conditions. More importantly, the coexistence of sulfonyl groups and nitrogen heterocycles provides both high-voltage antioxidant and flame-retardant functions; the sulfur- and nitrogen-containing SEI formed by the sulfur and nitrogen heterocycles also increases the thermal decomposition temperature. Therefore, lithium-ion batteries containing this type of multifunctional disulfonylimide compound exhibit both high-voltage and high-temperature resistance, demonstrating excellent cycle performance, high-temperature storage performance, and safety performance under high voltage. Furthermore, R is selected from fluorine or , * indicates the connection end, and n is an integer selected from 1 to 3.

[0012] Furthermore, the disulfonamide compounds of the present invention include at least one of compounds 1 to 6.

[0013] Compound 1 Compound 2

[0014] Compound 3 Compound 4

[0015] Compound 5 and Compound 6.

[0016] Furthermore, the mass percentage of the disulfonamide compound of the present invention in the non-aqueous electrolyte is 0.05% to 2%.

[0017] Furthermore, the lithium salt of the present invention is selected from at least one of lithium hexafluorophosphate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorobis(oxalate) phosphate, lithium tetrafluoroborate, lithium bis(oxalate) borate, lithium tetrafluorooxalate phosphate, lithium bis(trifluoromethanesulfonyl)imide, and lithium difluorosulfonylimide.

[0018] Furthermore, the non-aqueous organic solvent of the present invention is selected from at least one of ethylene carbonate, fluoroethylene carbonate, ethyl difluoroacetate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, propylene carbonate, butyl acetate, propyl propionate, ethyl propionate, and ethyl acetate.

[0019] Furthermore, the non-aqueous electrolyte of the present invention also includes an additive selected from at least one of vinylene carbonate, 1,3-propanesulfonate lactone, vinyl sulfate, 1,2-difluoroethylene carbonate, tris(trimethylsilane) phosphate, and tris(trimethylsilane) phosphite.

[0020] Furthermore, the mass percentage of the additives of the present invention in the non-aqueous electrolyte is 0.5% to 8%.

[0021] Another aspect of the present invention provides a lithium-ion battery, comprising a positive electrode material, a negative electrode material, and the aforementioned non-aqueous electrolyte of the present invention.

[0022] Furthermore, the cathode material of this invention is LiNi. x Co y Mn z M 1-x-y-z O2, LiNi x Co y Al z M 1-x-y-z At least one of O2, wherein M is any one of Mg, Cu, Zn, Sn, B, Ga, Cr, Sr, V and Ti, 0.5 ≤ x < 1.0, 0 <y<1.0,0<z<1.0,0.9<x+y+z≤1.0。

[0023] Furthermore, the negative electrode material of the present invention is at least one of artificial graphite, natural graphite, silicon suboxide, and silicon-carbon composite materials. Detailed Implementation

[0024] The maximum charging voltage of the lithium-ion battery of the present invention is 4.5V, and it includes a positive electrode material, a negative electrode material, and a non-aqueous electrolyte. Among them, the positive electrode material is LiNi x Co y Mn z M 1-x-y-z O2, LiNi x Co y Al z M 1-x-y-z O2, where M is any one of Mg, Cu, Zn, Sn, B, Ga, Cr, Sr, V, and Ti, 0.5 ≤ x < 1.0, 0 < y < 1.0, 0 < z < 1.0, 0.9 < x + y + z ≤ 1.0. Preferably, the positive electrode material of the present invention is LiNi 0.6 Co 0.2 Mn 0.2 O2. The negative electrode material is at least one of artificial graphite, natural graphite, silicon suboxide, and silicon-carbon composite material. Preferably, the negative electrode material of the present invention is artificial graphite. The non-aqueous electrolyte includes a lithium salt, a non-aqueous organic solvent, and an additive.

[0025] The lithium salt is selected from at least one of lithium hexafluorophosphate (LiPF6), lithium difluorophosphate (LiDFP), lithium difluorooxalate borate (LiDFOB), lithium difluorobis(oxalato)phosphate (LiDFOP), lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), lithium tetrafluorooxalate phosphate (LiTFOP), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), and lithium bis(fluorosulfonyl)imide (LiFSI). The mass percentage of the lithium salt in the non-aqueous electrolyte is 10% - 19.8%. As an example, the mass percentage of the lithium salt in the non-aqueous electrolyte can be, but is not limited to, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 19.8%.

[0026] The non-aqueous organic solvent is selected from at least one of ethylene carbonate (EC), fluoroethylene carbonate (FEC), ethyl difluoroacetate (DFEA), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), propylene carbonate (PC), butyl acetate (BA), propyl propionate (PP), ethyl propionate (EP), and ethyl acetate (EA). The mass percentage of the non-aqueous organic solvent in the non-aqueous electrolyte is 60% - 90%. As an example, the mass percentage of the non-aqueous organic solvent in the non-aqueous electrolyte can be, but is not limited to, 60, 65%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 82%, 84%, 85%, 86%, 88%, 90%.

[0027] Additives include disulfonamide compounds having the structure shown in Formula 1 or Formula 2:

[0028] Wherein, R is selected from halogen or * indicates a connection terminal, and n is an integer selected from 1 to 5. Further, R is selected from fluorine or... * indicates a connection end, and n is an integer selected from 1 to 3. Specifically, disulfonamide compounds include at least one of compounds 1 to 6.

[0029] Compound 1 Compound 2

[0030] Compound 3 Compound 4

[0031] Compound 5 and Compound 6.

[0032] Specifically, the synthetic routes for the disulfonamide compounds shown in structural formulas 1 and 2 are illustrated in reaction formulas 1 and 2. It should be noted that in reaction formula 2, fluorine is used as an example when R is selected from halogens.

[0033]

[0034] Reaction 1

[0035] Reaction 2 The synthesis method of reactant 1 refers to the synthesis process in the preparation method of 1,4-butanedisulfonyl chloride in patent CN118388378B. For structural formulas with different carbon chain lengths, simply replace the 1,4-dibromobutane raw material with dibromoalkane of different carbon chain lengths, such as 1,2-dibromoethane, 1,6-dibromohexane, etc. The CAS number of reactant 2 is 55589-62-3. In reaction formula two, "1" indicates that reactant 1 is in excess, and "2" indicates that reactant 2 is in excess.

[0036] The mass percentage of disulfonamide compounds in the non-aqueous electrolyte is 0.05% to 2%, preferably 0.1% to 1.5%. As an example, the mass percentage of disulfonamide compounds in the non-aqueous electrolyte can be, but is not limited to, 0.05%, 0.08%, 0.1%, 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, or 2%.

[0037] The non-aqueous electrolyte of the present invention may further include an additive selected from at least one of vinylene carbonate (VC), 1,3-propanesulfonate lactone (PS), vinyl sulfate (DTD), 1,2-difluoroethylene carbonate (DFEC), tris(trimethylsilane) phosphate (TMSP), and tris(trimethylsilane) phosphite (TMSPi). Vinylene carbonate (VC) exhibits excellent high and low temperature performance and anti-gas-swelling function, which can improve battery capacity and cycle life; tris(trimethylsilane) phosphate (TMSP) and tris(trimethylsilane) phosphite (TMSPi) can adsorb free acid, thereby improving battery cycle performance; 1,3-propanesulfonate lactone (PS) can improve battery cycle life and storage stability; vinyl sulfate (DTD) can increase the sulfur and oxygen content on the battery's SEI film, accelerating the shuttle ability of lithium ions on the SEI film through the arc pair electrons of sulfur and oxygen atoms, reducing the impedance of the SEI film, and thus improving the low-temperature discharge performance of the battery. The mass percentage of the additive in the non-aqueous electrolyte is 0.5% to 8%. As an example, the mass percentage of the additive in the non-aqueous electrolyte may be, but is not limited to, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, and 8%.

[0038] 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.

[0039] Example 1 In a nitrogen-filled glove box (O2 < 1 ppm, H2O < 2 ppm), ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed uniformly in a ratio of 3:2:5 to obtain 87 g of non-aqueous organic solvent. 0.5 g of compound 1 was added as an additive to obtain a mixed solution. The mixed solution was sealed and packaged, then frozen in a freezer (-4°C) for 2 hours. After removal, 12.5 g of lithium hexafluorophosphate (LiPF6) was slowly added to the mixed solution in a nitrogen-filled glove box (O2 < 1 ppm, H2O < 2 ppm), and mixed thoroughly to prepare the electrolyte. The electrolyte was prepared using LiNi with a maximum charging voltage of 4.5 V. 0.6 Co 0.2 Mn 0.2 Using O2 as the positive electrode material and artificial graphite as the negative electrode material, a lithium-ion battery was prepared using the electrolyte described in Example 1 and following conventional lithium battery preparation methods.

[0040] Examples 2-16 and 1-9 show the highest cutoff voltage and electrolyte formulations as shown in the table below: Table 1. Battery systems and electrolyte formulations for examples and comparative examples.

[0041] In the comparative examples, the specific structures of compounds A to E are shown in Table 2: Table 2

[0042] The lithium-ion batteries of Examples 1-16 and Comparative Examples 1-9 were subjected to room temperature cycling performance, high temperature storage performance and thermal abuse tests, respectively. The test conditions are as follows, and the test results are shown in Table 3.

[0043] Lithium-ion battery room temperature cycle performance test: The lithium-ion battery was placed in an environment of 25°C and charged at a constant current of 1C to 4.5V (the highest voltage shown in the comparison is 4.3V, which is changed to 4.3V here). Then it was charged at a constant voltage until the current dropped to 0.05C. Then it was discharged at a constant current of 1C to 3.0V. This cycle was repeated for 800 cycles. The discharge capacity of the first cycle and the discharge capacity of the last cycle were recorded. The capacity retention rate of the room temperature cycle was calculated using the following formula.

[0044] Capacity retention rate = (Discharge capacity in the last cycle / Discharge capacity in the first cycle) × 100% High-temperature storage performance test of lithium-ion batteries: The lithium-ion battery was placed in an environment of 25℃ and charged at a constant current of 0.5C to 4.5V (the highest voltage shown in the comparison is 4.3V, which is changed to 4.3V here). Then it was charged at a constant voltage until the current dropped to 0.05C. Then it was discharged at a constant current of 0.5C to 3.0V. The discharge capacity at this time was recorded as C1. Then the battery was charged at a constant current of 0.5C to 4.5V (the highest voltage shown in the comparison is 4.3V, which is changed to 4.3V here). Then it was charged at a constant voltage until the current dropped to 0.05C. The battery was then placed at a high temperature of 60℃ for 30 days. After that, the battery was taken out and placed at 25℃ for 2 hours. Then the battery was discharged at a constant current of 0.5C to 3.0V. The discharge capacity at this time was recorded as C2.

[0045] Capacity retention rate = C2 / C1 × 100% Lithium-ion thermal abuse test: Place the lithium-ion battery in an environment of 25°C and charge it at a constant current of 1C to 4.5V (the highest voltage shown in the comparison is 4.3V, so change it to 4.3V here). Then charge it at a constant voltage until the current drops to 0.05C. Place the fully charged battery in a hot box and heat it to 130°C±2°C at a rate of 5±2°C / min. Hold the temperature for 30 minutes and observe whether the battery catches fire or explodes.

[0046] Table 3 Performance test results of Examples 1-16 and Comparative Examples 1-9

[0047] As shown in Table 3, the room temperature cycling performance, high-stability storage performance, and hot box performance (thermal abuse test) of Examples 1-16 are all superior to those of Comparative Examples 1-6. This is because the additives in the non-aqueous electrolyte of the lithium-ion battery of the present invention include disulfonylimide compounds. When these multifunctional disulfonylimide compounds are used in lithium-ion batteries, the pyridine ring or thiadiazine ring in the molecule contains lone pairs of electrons, which can react with Li... + Coordination promotes molecular self-assembly and in-situ polymerization at the electrode / electrolyte interface. Flexible S-(CH2CH2) n The -S segments, under reducing conditions, break and recombine via SC bonds to form a three-dimensional network structure, enhancing the mechanical strength and ionic conductivity of the membrane. Especially at extremely high voltages (≥4.5V), this three-dimensional network structure possesses inherent high-voltage resistance, making the SEI membrane less prone to decomposition and damage under high voltage conditions. More importantly, the coexistence of sulfonyl groups and nitrogen heterocycles provides both high-voltage antioxidant and flame-retardant functions; the sulfur- and nitrogen-containing SEI formed by the sulfur and nitrogen heterocycles also increases the thermal decomposition temperature. Therefore, lithium-ion batteries containing this type of multifunctional disulfonylimide compound exhibit both high-voltage and high-temperature resistance, demonstrating excellent cycle performance, high-temperature storage performance, and safety performance under high voltage. Further comparison of Examples 1 and 12-16 shows that adding additives to Example 1 further improves the battery's cycle and storage performance.

[0048] Comparing Examples 1-16 with Comparative Examples 2-6, it is evident that the carbonate structures on both sides of Compound A are easily oxidized under high voltage, producing gases such as CO2 and CO, thus making it unsuitable for high-voltage systems. Compounds B and C have sulfate and phosphate structures on both sides. The sulfate / phosphate esters lack coordination sites, and ion conduction relies on the self-polymerization of the matrix itself. The sulfate / phosphate esters on both sides cannot promote self-assembly of molecules at the electrode / electrolyte interface, resulting in low polymerization efficiency and a low degree of polymerization. Consequently, the poor stability of the SEI under high voltage (≥4.5V) becomes apparent. Furthermore, although phosphate esters are flame-retardant, the thermal stability of the film-forming product is far lower than that of the disulfonylimide compounds of this invention, thus posing a challenge to battery safety. While Compound D and DTD can form complementary interfacial films at the electrode-electrolyte interface, both films are conventional SEI components without a three-dimensional polymer network, making them unable to withstand 4.5V high voltage and exhibiting significantly poor thermal safety performance. Compound E, due to its small molecular structure and single nitrogen-containing heterocycle, forms a thin SEI film that is mainly composed of small-molecule organic components. It is easily oxidized under high voltage and has poor thermal stability, resulting in rapid increase in interfacial impedance and significant capacity decay during cycling. Furthermore, it lacks multifunctional integration capabilities such as flame retardancy and oxidation resistance, which limits its application potential in 4.5V high-safety batteries.

[0049] Comparing Comparative Examples 2-4 and 7-9, it is evident that Compound A offers limited improvement to battery performance in both high-voltage (4.5V) and conventional-voltage (4.3V) systems. While Compounds B and C significantly enhance battery cycle and storage performance in conventional-voltage systems, their improvement in battery safety is relatively weak. Furthermore, the improvement in cycle and storage performance is greatly reduced when Compounds B and C are applied in high-voltage systems, likely due to the significantly lower voltage and thermal stability of their film-forming products compared to the disulfonylimide compounds described in this patent.

[0050] 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 disulfonamide compounds having the structural formula 1 or structural formula 2: Wherein, R is selected from halogen or , * indicates the connection end, and n is an integer selected from 1 to 5.

2. The electrolyte additive according to claim 1, characterized in that, R is selected from fluorine or , * indicates the connection end, and n is an integer selected from 1 to 3.

3. The non-aqueous electrolyte according to claim 1 or 2, characterized in that, The disulfonamide compounds include at least one of compounds 1 to 6. Compound 1 Compound 2 Compound 3 Compound 4 Compound 5 and Compound 6.

4. The non-aqueous electrolyte according to claim 1 or 2, characterized in that, The mass percentage of the disulfonamide compound in the non-aqueous electrolyte is 0.05% to 2%.

5. The non-aqueous electrolyte according to claim 1 or 2, characterized in that, The lithium salt is selected from at least one of lithium hexafluorophosphate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorobis(oxalate) phosphate, lithium tetrafluoroborate, lithium bis(oxalate) borate, lithium tetrafluorooxalate phosphate, lithium bis(trifluoromethanesulfonyl)imide, and lithium difluorosulfonylimide.

6. The non-aqueous electrolyte according to claim 1 or 2, characterized in that, The non-aqueous organic solvent is selected from at least one of ethylene carbonate, fluoroethylene carbonate, ethyl difluoroacetate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, propylene carbonate, butyl acetate, propyl propionate, ethyl propionate, and ethyl acetate.

7. The non-aqueous electrolyte according to claim 1 or 2, characterized in that, It also includes an adjuvant selected from at least one of vinylene carbonate, 1,3-propanesulfonate lactone, vinyl sulfate, 1,2-difluorovinyl carbonate, tris(trimethylsilane) phosphate, and tris(trimethylsilane) phosphite.

8. The non-aqueous electrolyte according to claim 7, characterized in that, The mass percentage of the additive in the non-aqueous electrolyte is 0.5% to 8%.

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 8.

10. The lithium-ion battery according to claim 9, characterized in that, The positive electrode material is LiNi x Co y Mn z M 1-x-y- z O2, LiNi x Co y Al z M 1-x-y-z O2, or at least one of them. Here, M is any one of Mg, Cu, Zn, Sn, B, Ga, Cr, Sr, V, and Ti, 0.5 ≤ x < 1.0, 0 < y < 1.0, 0 < z < 1.0, 0.9 < x + y + z ≤ 1.

0. The negative electrode material is at least one of artificial graphite, natural graphite, silicon monoxide, and silicon-carbon composite material.

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