Non-aqueous electrolyte and lithium ion battery

Abstract

The invention provides a non-aqueous electrolyte and a lithium ion battery. The non-aqueous electrolyte comprises an electrolyte salt, a non-aqueous organic solvent and an additive. The additive comprises a compound A shown as a structural formula I, X is carbon, sulfur or phosphorus, m, n, y and z are respectively and independently 0 or 1, y + z = 0 or y + z = 1, and R1 is halogen-substituted C1-C6 alkyl or unsubstituted C1-C6 alkyl. The non-aqueous electrolyte contains the compound A, so that the fast charging and high-temperature storage performance of a high-capacity battery can be improved, and the non-aqueous electrolyte is particularly suitable for a lithium ion battery containing a silicon negative electrode. # imgabs0 # structural formula I

Description

Technical Field

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

[0002] As a green, environmentally friendly, high-energy battery, lithium-ion batteries are currently the world's most ideal and promising rechargeable battery. Compared to other batteries, they offer a range of advantages, including no memory effect, rapid charge and discharge, high energy density, long cycle life, and environmental friendliness. Consequently, they are widely used in small electronic devices such as laptops, camcorders, mobile phones, and electronic watches, as well as large-scale power transmission equipment such as electric vehicles and energy storage systems. With the increasing demand for lithium-ion battery capacity in pure electric vehicles, hybrid electric vehicles, and portable energy storage devices, the development of fast-charging and high-capacity lithium-ion batteries is highly anticipated to improve the convenience of our lives.

[0003] Currently, the industry is increasing the charging current to improve the charging speed of lithium-ion batteries. However, this increase in charging speed leads to localized lithium deposition. Furthermore, because the rate of lithium ion embedding into graphite is slower than the rate of lithium ion migration, a large amount of lithium accumulates, further exacerbating lithium ion deposition and making the formation of lithium dendrites more likely. Lithium dendrites, in turn, cause continuous decomposition and regeneration at the electrode-electrolyte interface, leading to continuous electrolyte consumption and ultimately poor cycling performance of lithium-ion batteries.

[0004] In addition, in order to improve the capacity of power batteries, one of the effective ways is to increase the silicon content in graphite negative electrode materials. This is the trend of battery development and an inevitable requirement for the development of new energy vehicles. Although at the same cut-off voltage, the higher the silicon content of the graphite negative electrode material, the more Li + , thus achieving higher capacity output, however, a large amount of Li + After embedding, the high-lithium-ionization silicon anode material experiences a 300% volume expansion, leading to continuous cracking and regeneration of the electrode-electrolyte interface, capacity decay during material cycling, and decreased thermal stability. Furthermore, the high-silicon graphite anode material has a high surface -OH content. Conventional electrolytes in high-silicon batteries are easily reduced and decomposed on the anode surface. This is especially accelerated under fast-charging conditions, which can accelerate the reduction and decomposition of the electrolyte and cause the silicon anode material to deteriorate.

[0005] Therefore, how to provide a lithium-ion battery with good comprehensive performance is a technical problem that needs to be solved urgently. Summary of the Invention Based on the above problems, the purpose of the present invention is to provide a non-aqueous electrolyte and a lithium-ion battery. The non-aqueous electrolyte contains compound A, which can improve the fast charging and high-temperature storage performance of high-capacity batteries, and is particularly suitable for lithium-ion batteries containing silicon negative electrodes.

[0006] To achieve the above objectives, the present invention provides a non-aqueous electrolyte in one aspect. The non-aqueous electrolyte comprises an electrolyte salt, a non-aqueous organic solvent, and an additive. The additive comprises a compound A as represented by structural formula I, wherein X represents carbon, sulfur, or phosphorus; m, n, y, and z are each independently 0 or 1, and y+z=0 or y+z=1; and R1 represents a halogen-substituted C1-C6 hydrocarbon group or an unsubstituted C1-C6 hydrocarbon group.

[0007]

[0008] Structural Formula Ⅰ The non-aqueous electrolyte of the present invention contains compound A, which is a cyclic unsaturated bond compound containing a linked ring, and therefore has relatively low oxidation potential and reduction potential. Its low potential characteristic can form a thinner interface layer on the electrode surface before the solvent is oxidized, which can reduce the ion transmission path and improve the gas production problem of the battery at high voltage, thereby improving the cycle performance. More importantly, compound A contains a -SO-SO- structure. The SEI formed by this structure has a high lithium ion transmission rate, which can greatly improve the fast charging capability of the lithium ion battery. The interface protective layer formed by the -OXOO- bond within the ring has high high voltage and high temperature resistance, which can greatly improve the high temperature storage characteristics of high-voltage lithium ion batteries.

[0009] As a technical solution of the present invention, R1 is a fluorine-substituted C1~C3 alkyl group or an unsubstituted C1~C3 alkyl group.

[0010] As a technical solution of the present invention, X is sulfur and y is 0.

[0011] As a technical solution of the present invention, X is phosphorus, y is 1, and R1 is a C1-C3 alkyl group.

[0012] As a technical solution of the present invention, the compound A is selected from at least one of compounds 1 to 6.

[0013]

[0014] Compound 1 Compound 2 Compound 3

[0015] Compound 4 Compound 5 Compound 6 As a technical solution of the present invention, the mass proportion of the compound A in the non-aqueous electrolyte is 0.1-5.0%.

[0016] As a technical solution of the present invention, the mass proportion of the electrolyte salt in the non-aqueous electrolyte is 5~25%, and the electrolyte salt is selected from at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide, lithium methanesulfonate, lithium trifluoromethylsulfonate, lithium fluorosulfonate, lithium bis(oxalato)borate, lithium difluorooxalatoborate, lithium difluorophosphate, lithium difluorobis(oxalato)phosphate, lithium bis(fluorosulfonyl)imide, lithium diphosphate and lithium bis(trifluoromethylsulfonyl)imide.

[0017] As a technical solution of the present invention, the non-aqueous organic solvent includes at least one of carbonate, carboxylate and ether compounds.

[0018] A second 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.

[0019] As a technical solution of the present invention, the negative electrode material includes a carbon material and a silicon material, or the negative electrode material includes a silicon-carbon composite material, the carbon material includes at least one of artificial graphite, natural graphite, soft carbon and hard carbon, and the silicon material includes at least one of elemental silicon and silicon-oxygen composite material. DETAILED DESCRIPTION

[0020] The non-aqueous electrolyte of the present invention can improve the fast-charging and high-temperature storage performance of lithium-ion batteries, and is particularly suitable for lithium-ion batteries containing silicon anodes. For lithium-ion batteries containing silicon anodes, the capacity retention rate remains above 70% after 400 cycles at room temperature (4.0°C) and high rate, respectively. It also maintains a capacity retention rate of over 68% after 300 cycles at 45°C and high rate, respectively. Furthermore, after 30 days of storage at 60°C, the capacity retention rate remains above 70%, and the thickness expansion rate is less than 12%.

[0021] The lithium-ion battery of the present invention may include a positive electrode material, a negative electrode material, and a non-aqueous electrolyte.

[0022] Among them, the positive electrode material can be 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 can be lithium cobalt oxide or lithium cobalt oxide modified by doping or coating, the lithium iron phosphate material can be lithium iron phosphate or lithium iron phosphate modified by doping or coating, the nickel cobalt manganese oxide can be nickel cobalt manganese oxide or nickel cobalt manganese oxide modified by doping or coating, and the nickel cobalt aluminum oxide can be nickel cobalt aluminum oxide or nickel cobalt aluminum oxide modified by doping or coating. In particular, the positive electrode material is LiNi x Co y Mn z M 1-x-y-z O2 or LiNi x Co y Al z M 1-x-y-zO2, 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. A relatively high capacity can be obtained by using this positive electrode material.

[0023] The negative electrode material includes a carbon material and a silicon material, or the negative electrode material includes a silicon-carbon composite material. The carbon material includes at least one of artificial graphite, natural graphite, soft carbon, and hard carbon. The silicon material includes at least one of elemental silicon and a silicon-oxygen composite material. That is, the negative electrode material can be a silicon-carbon composite material or a mixture of a carbon material and a silicon material, that is, the negative electrode material is a mixture of silicon and carbon. The capacity is increased by silicon, but the proportion of silicon should not be too high to avoid an excessive expansion rate. The mass proportion of silicon in the negative electrode material should not exceed 25%.

[0024] The non-aqueous electrolyte includes an electrolyte salt, a non-aqueous organic solvent, and an additive.

[0025] The mass proportion of the electrolyte salt in the non-aqueous electrolyte is 5 - 25%. Further, the mass proportion of the electrolyte salt in the non-aqueous electrolyte is 8 - 20%. More specifically, the mass proportion is 10 - 15%. As an example, the mass proportion of the electrolyte 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 proportion of the electrolyte salt is not limited to the listed values, and other unlisted values within this numerical range are equally applicable. The electrolyte salt includes at least one of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), lithium methyl sulfonate (LiCH3SO3), lithium trifluoromethanesulfonate (LiCF3SO3), lithium fluorosulfonate (LiSO2F), lithium bis(oxalato)borate (LiBC4O8), lithium difluoro(oxalato)borate (LiBF2C2O4), lithium difluorophosphate (LiPO2F2), lithium difluoro(bis(oxalato))phosphate (LiDFBP), lithium bis(fluorosulfonyl)imide, lithium diphosphate (LiPO2F2), and lithium bis(trifluoromethylsulfonyl)imide (LiTFSI).

[0026] The non-aqueous organic solvent includes at least one of a carbonate, a carboxylate, and an ether compound. Furthermore, carbonates include, but are not limited to, cyclic carbonates and chain carbonates. Cyclic carbonates may include, but are not limited to, ethylene carbonate (EC), propylene carbonate, butylene carbonate (BC), pentylene carbonate, vinylene carbonate (VC), or derivatives thereof. Chain carbonates include, but are not limited to, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and propylene carbonate (PC). Carboxylates include, but are not limited to, cyclic carboxylates and chain carboxylates. Specifically, cyclic carboxylates may include, but are not limited to, at least one of γ-butyrolactone, γ-valerolactone, and δ-valerolactone. Chain carboxylates include, but are not limited to, at least one of methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), butyl acetate, propyl propionate (PP), and butyl propionate. Ether compounds include cyclic ethers or chain ethers. Cyclic ethers include, but are not limited to, at least one of 1,3-dioxolane (DOL), 1,4-dioxolane (DX), crown ethers, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH3-THF), and 2-trifluoromethyltetrahydrofuran (2-CF3-THF). Chain ethers include, but are not limited to, at least one of dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

[0027] The additive includes compound A as shown in structural formula I. wherein X represents carbon, sulfur, or phosphorus, m, n, y, and z are each independently 0 or 1, and y+z=0 or y+z=1, and R1 represents a halogen-substituted C1-C6 hydrocarbon group or an unsubstituted C1-C6 hydrocarbon group. Furthermore, R1 can be a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, a halogen-substituted C1-C6 alkyl group, a halogen-substituted C2-C6 alkenyl group, or a halogen-substituted C2-C6 alkynyl group. Furthermore, R1 represents a fluorine-substituted C1-C3 alkyl group or an unsubstituted C1-C3 alkyl group. For example, R1 can be methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, cyclohexyl, vinyl, propenyl, isopropenyl, butenyl, sec-butenyl, tert-butenyl, pentenyl, cyclohexenyl, ethynyl, propynyl, isopropynyl, butynyl, sec-butynyl, tert-butynyl, pentynyl, cyclohexynyl, monofluoromethyl, monofluoroethyl, monofluoropropyl, monofluoroisopropyl, monofluorobutyl, monofluorosec-butyl, monofluorotert-butyl, monofluoropentyl, monofluorocyclohexyl, monofluorovinyl, monofluoropropenyl, monofluoroisopropenyl, monofluorobutenyl, monofluorosec-butenyl, monofluorotert-butenyl, monofluoropentenyl, monofluorocyclohexenyl, monofluoro ethynyl, monofluoropropynyl, monofluoroisopropynyl, monofluorobutynyl, monofluorosec-butynyl, monofluorotert-butynyl, monofluoropentynyl, monofluorocyclohexynyl, polyfluoromethyl, polyfluoroethyl, polyfluoropropyl, polyfluoroisopropyl, polyfluorobutyl, polyfluorosec-butyl, polyfluorotert-butyl, polyfluoropentyl, polyfluorocyclohexyl, polyfluorovinyl, polyfluoropropenyl, polyfluoroisopropenyl, polyfluorobutenyl, polyfluorosec-butenyl, polyfluorotert-butenyl, polyfluoropentenyl, polyfluorocyclohexenyl, polyfluoroethynyl, polyfluoropropynyl, polyfluoroisopropynyl, polyfluorobutynyl, polyfluorosec-butynyl, polyfluorotert-butynyl, polyfluoropentynyl, polyfluorocyclohexenyl. m may be 0 or 1, n may be 0 or 1, x may be 0 or 1, and y may be 0 or 1. Furthermore, when X is sulfur, y is 0, or when X is phosphorus, y is 1, and R1 is a C1-C3 alkyl group.

[0028]

[0029] Structural Formula Ⅰ Furthermore, compound A is selected from at least one of compound 1 to compound 6. The synthesis process of compound 1 to compound 6 can be shown in reaction formula 1.

[0030]

[0031] Compound 1 Compound 2 Compound 3

[0032] Compound 4 Compound 5 Compound 6

[0033] Reaction 1 The mass proportion of compound A in the non-aqueous electrolyte is 0.1-5.0%. Further, the mass proportion of compound A in the non-aqueous electrolyte is 0.5-3.0%. Even more preferably, the mass proportion is 0.5-2.0%. As an example, the mass proportion of compound A can be, but is not limited to, 0.1%, 0.5%, 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 values not listed within this numerical range are also applicable.

[0034] In order to further illustrate the purpose, technical solutions and beneficial effects of the present invention, the present invention will be further described below with reference to specific examples. It should be noted that compounds 1 to 6 can be obtained by referring to the reaction of Reaction Formula 1. For other raw materials in the examples and comparative examples, if the specific conditions are not specified, they can be carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments used, if the manufacturer is not specified, they are all conventional products that can be obtained commercially.

[0035] Example 1 1.1 Preparation of electrolyte In a nitrogen-filled glove box (O<1ppm, H<1ppm), ethylene carbonate (EC), propylene carbonate (PC), propyl acetate (EP), and propyl propionate (PP) were mixed in a mass ratio of 2:1:5:2 to form a mixed solvent, which was then added to compound 1 to obtain a mixed solution. The mixed solution was sealed and packaged and placed in a quick freezer (-4°C) for 2 hours before being removed. Lithium hexafluorophosphate was then slowly added to the mixed solution in a nitrogen-filled glove box (O<1ppm, H<1ppm). After mixing, the electrolyte was prepared.

[0036] 1.2 Preparation of positive electrode The ternary material LiNi 0.6 Co 0.2 Mn 0.2 Zr 0.03O2, conductive agent SuperP, adhesive PVDF and carbon nanotubes (CNT) are mixed evenly in a mass ratio of 97:1:1:1 to form a lithium-ion battery positive electrode slurry with a certain viscosity, coated on the aluminum foil for current collector, dried at 85°C and cold pressed, and then trimmed, cut and striped. After stripping, it is dried at 85°C under vacuum conditions for 4 hours, and the tabs are welded to make lithium-ion battery positive electrode sheets that meet the requirements.

[0037] 1.3 Preparation of negative electrode Artificial graphite and elemental silicon are mixed in a mass ratio of 92:8, and then mixed with conductive agent SuperP, thickener CMC, and adhesive SBR (styrene-butadiene rubber emulsion) in a mass ratio of 95:1.5:1.0:2.5 to make a slurry. The mixture is evenly mixed, and the mixed slurry is coated on both sides of the copper foil. After drying and rolling, the negative electrode sheet is obtained to make a lithium-ion battery negative electrode sheet that meets the requirements. 1.4 Preparation of lithium-ion batteries: The positive electrode sheet, negative electrode sheet and separator prepared according to the above process were laminated to form a lithium-ion battery with a thickness of 4.7mm, a width of 55mm and a length of 60mm. The battery was vacuum-baked at 75°C for 10 hours and then injected with the above electrolyte. After standing for 24 hours, the battery was charged to 4.45V with a constant current of 0.1C (180mA), then charged at a constant voltage of 4.45V until the current dropped to 0.05C (90mA); then discharged to 3.0V at 0.2C (180mA), and the charge and discharge cycle was repeated twice. Finally, the battery was charged to 3.8V at 0.2C (180mA) to complete the production of the lithium-ion battery.

[0038] The components and contents of the electrolytes of Examples 1 to 11 and Comparative Examples 1 to 2 are shown in Table 1. The preparation processes of the lithium-ion battery electrolytes, positive electrode sheets, negative electrode sheets, and lithium-ion batteries of Examples 2 to 11 and Comparative Examples 1 to 2 are the same as those of Example 1.

[0039] Table 1 Compositions of the electrolytes of Examples and Comparative Examples

[0040] The structural formula of compound 7 in Table 1 above is shown below.

[0041]

[0042] The lithium-ion batteries prepared in Examples 1 to 11 and Comparative Examples 1 to 2 were subjected to high-temperature storage performance test, high-temperature cycle performance test, room-temperature fast charge cycle performance test, and high-temperature fast charge cycle performance test under the following conditions. The results are shown in Table 2.

[0043] (1) High temperature storage performance test At room temperature (25°C), the lithium-ion battery was charged and discharged at 0.5C / 0.5C (the battery discharge capacity was recorded as C0), with an upper limit voltage of 4.4V. The battery was then charged to 4.4V under 0.5C constant current and constant voltage conditions, and the battery thickness was measured (the thickness was recorded as D0). The battery was placed in a 60°C oven for 30 days, taken out and the battery thickness was measured (the thickness was recorded as D1). The battery was placed in a 25°C environment and discharged at 0.5C (the discharge capacity was recorded as C1). The lithium-ion battery was continued to be charged and discharged at room temperature (25°C) at 0.5C / 0.5C (the battery discharge capacity was recorded as C2), with an upper limit voltage of 4.4V, and the capacity retention rate and thickness expansion rate were calculated.

[0044] Capacity retention rate = (C1 / C0)*100% Thickness expansion rate = (D1 / D0)*100% (2) High temperature cycle test At an elevated temperature (45°C), the lithium-ion battery was charged and discharged once at a 1.0C / 1.0C rate (the battery discharge capacity is C0) with an upper voltage limit of 4.4V. Then, the battery was charged and discharged at a 1.0C / 1.0C rate for 400 cycles at room temperature (the battery discharge capacity is C1). The capacity retention rate was calculated.

[0045] Capacity retention rate = (C1 / C0)*100% (3) Normal temperature fast charging performance test At room temperature (25°C), the lithium-ion battery is charged and discharged once at 1.0C / 1.0C (the battery discharge capacity is C0) with an upper voltage of 4.4V. Then, it is charged and discharged at 4.0C / 1.0C for 400 cycles at room temperature (the battery discharge capacity is C1). Calculate the capacity retention rate.

[0046] Capacity retention rate = (C1 / C0)*100% (4) High temperature fast charging performance test At high temperature (45°C), the lithium-ion battery is charged and discharged once at 1.0C / 1.0C (battery discharge capacity is C0) with an upper voltage of 4.4V. Then, it is charged and discharged at 4.0C / 1.0C for 300 cycles at high temperature (45°C) (battery discharge capacity is C1). The capacity retention rate is calculated.

[0047] Capacity retention rate = (C1 / C0)*100% Table 2 Test results of lithium-ion battery performance

[0048] From the results in Table 2, it can be seen that compared with Comparative Examples 1 to 2, the high-temperature storage, high-temperature cycle, room-temperature fast charge and high-temperature fast charge performance of Examples 1 to 11 after the addition of Compounds 1 to 6 are all better. This is because Compound A not only contains a linked cyclic unsaturated bond and an intra-ring -OXOO- bond, but also contains a -SO-SO- structure in Compound A. The SEI formed by this structure has a higher lithium ion transmission rate, which can greatly improve the fast charge capability of the lithium-ion battery. In Comparative Example 1, although it also contains a linked cyclic unsaturated bond and an intra-ring -OXOO- bond, the high-temperature storage and high-temperature cycle are also better, but the SEI formed by this compound is not very stable under fast charge conditions and is easy to decompose. In particular, under high-temperature fast charge, the interface is constantly broken and regenerated, and the electrode electrolyte interface is in direct contact to generate gas, which deteriorates the performance of the battery.

[0049] A comparison of Examples 1-6 shows that Compound A, when Compound 5 is present, exhibits superior performance. This is due to Compound 5's ability to form a sulfur-rich SEI at the electrolyte-battery interface. This SEI exhibits low lithium-ion transport resistance, facilitating rapid lithium-ion transport. Furthermore, this SEI exhibits excellent thermal stability, maintaining its SEI morphology at high temperatures. This isolates the electrolyte from direct contact with active groups, inhibiting electrolyte side reactions and significantly improving the battery's high- and low-temperature performance.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A non-aqueous electrolyte comprising an electrolyte salt, a non-aqueous organic solvent, and an additive, wherein the additive comprises a compound A as shown in structural formula I, wherein: X is carbon, sulfur or phosphorus, m, n, y, z are each independently 0 or 1, and y+z=0 or y+z=1, R1 is a halogen-substituted C1~C6 hydrocarbon group or an unsubstituted C1~C6 hydrocarbon group, Structural formula Ⅰ.

2. The non-aqueous electrolyte according to claim 1, characterized in that R1 is a fluorine-substituted C1~C3 alkyl group or an unsubstituted C1~C3 alkyl group.

3. The non-aqueous electrolyte according to claim 1, characterized in that X is sulfur, and y is 0.

4. The non-aqueous electrolyte according to claim 1, wherein X is phosphorus, y is 1, and R1 is a C1-C3 alkyl group.

5. The non-aqueous electrolyte according to claim 1, characterized in that The compound A is selected from at least one of compound 1 to compound 6, Compound 1 Compound 2 Compound 3 Compound 4 Compound 5 Compound 6 6. The non-aqueous electrolyte according to claim 1, characterized in that The mass ratio of the compound A in the non-aqueous electrolyte is 0.1-5.0%.

7. The non-aqueous electrolyte according to claim 1, characterized in that The electrolyte salt accounts for 5 to 25% by mass in the non-aqueous electrolyte, and the electrolyte salt is selected from at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethylsulfonyl imide, lithium methanesulfonate, lithium trifluoromethylsulfonate, lithium fluorosulfonate, lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium difluorophosphate, lithium difluorobisoxalatophosphate, lithium bisfluorosulfonyl imide, lithium diphosphate and lithium bistrifluoromethylsulfonyl imide.

8. The non-aqueous electrolyte according to claim 1, wherein The non-aqueous organic solvent includes at least one of carbonate, carboxylate and ether compounds.

9. A lithium-ion 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 lithium-ion battery according to claim 9, characterized in that The negative electrode material includes a carbon material and a silicon material, or the negative electrode material includes a silicon-carbon composite material, the carbon material includes at least one of artificial graphite, natural graphite, soft carbon and hard carbon, and the silicon material includes at least one of elemental silicon and a silicon-oxygen composite material.

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