Electrolyte and lithium ion battery

Abstract

The application discloses an electrolyte and a lithium ion battery. The electrolyte comprises an electrolyte salt, an organic solvent and an additive, and the additive comprises a compound A shown in a structural formula I. Wherein R1-R4 are independently C=R5 or CR6R7, R5 is an alkylene group, and R6-R7 are independently hydrogen, halogen, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl or cyano. The compound A has a relatively low oxidation potential and viscosity. The low potential feature of the compound A can be oxidized before the solvent, and a thin interface layer is formed on the electrode surface. The interface layer is not easy to shrink at low temperature, can maintain the lithium ion transmission channel at low temperature, and improves the low temperature performance of the lithium ion battery. The low viscosity feature is beneficial to the rapid migration of ions under fast charging conditions, and can support the fast charging characteristics of the secondary battery. The compound A has a double oxygen-containing heterocyclic structure, can complex residual alkali on the surface of a high-nickel ternary positive electrode material, reduces the interface side reaction of the battery during the cycle and storage process, and effectively inhibits the decomposition of the SEI film interface.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of secondary batteries, and particularly relates to an electrolyte and a lithium ion battery. BACKGROUND

[0002] As a kind of green and environmental protection high-energy battery, the secondary battery is the most ideal and potential rechargeable battery in the world. Especially the lithium ion battery in the secondary battery, compared with other batteries, has a series of advantages such as no memory effect, fast charge and discharge, high energy density, long cycle life and no environmental pollution, and is widely used in small electronic devices such as notebook computers, video cameras, mobile phones, electronic watches and the like, and large power transmission devices such as electric vehicles and energy storage. Nowadays, with the increasing demand for lithium ion battery capacity of pure electric vehicles, hybrid electric vehicles and portable energy storage devices, people expect to develop lithium ion batteries with fast charging capacity and high capacity to improve the convenience of people's life.

[0003] At present, the industry improves the charging speed of the lithium ion battery by improving the charging current, but with the improvement of the charging speed, local lithium deposition is caused. At the same time, since the lithium ion insertion rate of graphite is lower than the lithium ion migration rate, a large amount of lithium is accumulated, which will further aggravate the deposition of lithium ions, and lithium dendrites are more likely to be generated. Lithium dendrites will cause continuous decomposition and regeneration of the electrode electrolyte interface, continuous consumption of the electrolyte, and finally lead to poor performance of the lithium ion battery.

[0004] In addition, one of the effective ways to improve the capacity of the power battery at present is to increase the nickel content in the ternary positive electrode material, which is the development trend of the battery and the inevitable requirement of the development of new energy vehicles. Although the higher the nickel content of the ternary positive electrode material is, the more Li + can be extracted under the same cut-off voltage, thereby realizing higher capacity output; however, a large amount of Li + is extracted from the high lithium ion state positive electrode material, which is very unstable in structure, thereby causing problems of cycle capacity attenuation and thermal stability decline of the material. In addition, the surface residual alkali content of the high-nickel ternary positive electrode material is high, and the conventional electrolyte is easily oxidized and decomposed on the surface of the positive electrode, especially under fast charging conditions, which will accelerate the oxidation and decomposition of the electrolyte and promote the deterioration reaction of the positive electrode material.

[0005] Therefore, how to provide a lithium ion battery with good comprehensive performance is a technical problem to be solved at present. SUMMARY

[0006] The purpose of the present application is to provide an electrolyte and a lithium ion battery, which has better high-temperature and low-temperature performance, is beneficial to the rapid migration of ions under fast charging conditions of the battery, and meets the demand of high capacity and fast charging of the secondary battery.

[0007] To achieve the above object, the present application provides an electrolyte, comprising an electrolyte salt, an organic solvent and an additive, the additive comprising a compound A as shown in structural formula I. Wherein, R1-R4 are each independently C=R5 or CR6R7, R5 is an alkylene group, R6-R7 are each independently hydrogen, halogen, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl or cyano. The viscosity of the compound A is 1-3 mba / cm.

[0008]

[0009] Compared with the prior art, the electrolyte of the present application contains the compound A, which is a bicyclic ether ketone compound, and thus has a relatively low oxidation potential and viscosity (viscosity of 1-3 mba / cm). The low potential feature of the compound A can be oxidized before the solvent to form a thin interface layer on the electrode surface, which can reduce the ion transmission path and improve the gas production problem of the battery at high voltage. In addition, the interface layer is not prone to shrinkage at low temperature, and can maintain the lithium ion transmission channel at low temperature to improve the low temperature (such as-20℃) performance of the lithium ion battery. The low viscosity feature is also conducive to the rapid migration of ions under fast charging conditions, which can support the fast charging characteristics of the secondary battery. Furthermore, the compound A has a double oxygen-containing heterocyclic structure, which can complex the residual alkali on the surface of the high-nickel ternary positive electrode material, so as to reduce the interface side reaction of the battery during the cycle and storage process, effectively inhibit the decomposition of the SEI film interface, and further improve the high-temperature storage and high-temperature cycle performance of the secondary battery.

[0010] Wherein, the alkylene group can be methylene, ethylene, propylene, etc. The halogen can be fluorine or chlorine. The C1-C6 alkyl represents an alkyl group with 1-6 carbon atoms, which can be a chain alkyl group or a cyclic alkyl group, and the alkyl group can be but not limited to methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl and cyclohexyl, etc. The C2-C6 alkenyl represents an alkenyl group with 2-6 carbon atoms, which can be a chain alkenyl group or a cyclic alkenyl group, and the alkenyl group can be but not limited to vinyl, propenyl, isopropenyl, butenyl, sec-butenyl, tert-butenyl, pentenyl and cyclohexenyl, etc. The C2-C6 alkynyl represents an alkynyl group with 2-6 carbon atoms, which can be a chain alkynyl group or a cyclic alkynyl group, and the alkynyl group can be but not limited to ethynyl, propynyl, isopropynyl, butynyl, sec-butyryl, tert-butyryl, pentynyl and cyclohexynyl, etc. The cyano refers to a group containing-CN. As preferred, R1-R4 are each independently C=CH2 or CR6R7, and R6-R7 are each independently hydrogen, C1-C3 alkyl, C2-C3 alkenyl, C2-C3 alkynyl.

[0011] As a technical solution of the present application, the compound A is selected from at least one of compound 1-compound 6.

[0012]

[0013] As a technical solution of the present application, the mass of compound A accounts for 0.1% to 5.0% of the total mass of the electrolyte. As an example, the mass of compound A accounts for 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0% of the total mass of the electrolyte, but is not limited to the listed values. Other values not listed in this range are also applicable.

[0014] As a technical solution of the present application, the electrolyte salt includes at least one of lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethylsulfonylimide (LiTFSI), lithium methylsulfonate (LiCH3SO3), lithium trifluoromethylsulfonate (LiCF3SO3), lithium fluorosulfonate (LiSO2F), lithium bis(oxalato)borate (LiBC4O8), lithium difluoro(oxalato)borate (LiBF2C2O4), lithium difluorophosphate (LiPO2F2), lithium difluorobis(oxalato)phosphate (LiDFBP), lithium diphosphate (LiPO2F2), lithium bis-trifluoromethylsulfonylimide (LiTFSI), and lithium lower aliphatic carboxylate. Further, the lithium lower aliphatic carboxylate includes but is not limited to lithium chloroborane, lithium tetraphenylborate, lithium imide salt, etc.

[0015] As a technical solution of the present application, the mass of the electrolyte salt accounts for 5% to 25% of the total mass of the electrolyte. Further, the mass of the electrolyte salt accounts for 6% to 20% of the total mass of the electrolyte, preferably, the mass of the electrolyte salt accounts for 8% to 18% of the total mass of the electrolyte. As an example, the mass of the electrolyte salt accounts for 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 24% of the total mass of the electrolyte, but is not limited to the listed values. Other values not listed in this range are also applicable.

[0016] As a technical solution of the present application, the organic solvent includes at least one of carbonates, carboxylates and ethers. Further, the carbonates include, but are not limited to, cyclic carbonates, chain carbonates. The cyclic carbonates can be, but are not limited to, ethylene carbonate (EC), propylene carbonate, butylene carbonate (BC), pentylene carbonate, vinylene carbonate (VC) or derivatives thereof. The chain carbonates include, but are not limited to, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), propylene carbonate (PC). The carboxylates include, but are not limited to, cyclic carboxylates, chain carboxylates. The cyclic carboxylates can specifically include, but are not limited to, at least one of γ-butyrolactone, γ-valerolactone, δ-valerolactone. The 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. The ethers include cyclic ethers or chain ethers. The cyclic ethers include, but are not limited to, at least one of 1,3-dioxolane (DOL), 1,4-dioxane (DX), crown ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH3-THF) and 2-trifluoromethyltetrahydrofuran (2-CF3-THF). The chain ethers include, but are not limited to, at least one of dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethyleneglycol di-n-propyl ether, ethyleneglycol di-n-butyl ether and diethyleneglycol dimethyl ether.

[0017] As a technical solution of the present application, the electrolyte further includes an additive selected from at least one of vinylene carbonate, vinylene carbonate ethylene, fluoroethylene carbonate, vinyl sulfite, 1,3-propane sulfite, 1,3-propylene sulfite, 1,4-butane sulfite, vinyl sulfate, succinic anhydride, maleic anhydride, 2-methyl maleic anhydride, methyl carbonate-2-propargyl, tetraethylenesilane, triallyl isocyanurate, hexamethylene diisocyanate, o-phenanthroline, p-phenylene diisocyanate, 2,4-toluene diisocyanate, N-phenyl bis(trifluoromethanesulfonyl) imide, bisvinyl sulfate, methyl phenyl sulfonate, bisvinyl sulfate, bispropylene sulfite, p-phenylenediamine difluorosulfonate, triallyl phosphate, tripropargyl phosphate, 2,4-butane sulfite, isocyanatoethyl methacrylate, methanedi sulfonate, tris(trimethylsilyl) borate, tris(trimethylsilyl) phosphate and tris(vinyldimethylsilyl) phosphate. As an example, the additive is fluoroethylene carbonate (FEC), and further, the additive is a mixture of vinylene carbonate and fluoroethylene carbonate.

[0018] As a technical solution of the present application, the mass of the additive accounts for 0.1-5.0% of the total mass of the electrolyte, further, the mass of the additive accounts for 0.2-2.0% of the total mass of the electrolyte. As an example, the mass of the additive accounts for 0.1%, 0.2%, 0.5%, 0.8%, 1.0%, 1.5%, 2.0%, 2.2%, 2.5%, 3.0%, 3.2%, 3.5%, 3.8%, 4.0%, 4.2%, 4.5%, 4.8%, 5.0% of the total mass of the electrolyte, but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0019] The present application also provides a lithium ion battery comprising the above-mentioned electrolyte, a positive electrode material and a negative electrode material. The lithium ion battery has good high-temperature storage and high-temperature cycle performance, and also has good low-temperature performance, especially good low-temperature performance at -20℃.

[0020] As a technical solution of the present application, 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- z 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. The negative electrode material comprises at least one of a carbon-based negative electrode, a silicon-based negative electrode, a tin-based negative electrode and a lithium negative electrode. The carbon-based negative electrode can comprise graphite, hard carbon, soft carbon, graphene, mesocarbon microbeads, etc. The silicon-based negative electrode can comprise silicon material, oxide of silicon, silicon-carbon composite material and silicon alloy material, etc. The tin-based negative electrode can comprise tin, tin-carbon, tin-oxygen, tin metal compound. The lithium negative electrode can comprise metal lithium or lithium alloy. The lithium alloy can be at least one of lithium-silicon alloy, lithium-sodium alloy, lithium-potassium alloy, lithium-aluminum alloy, lithium-tin alloy and lithium-indium alloy. DETAILED DESCRIPTION

[0021] In order to further illustrate the purpose, technical solution and beneficial effects of the present application, the present application will be further described below in conjunction with specific examples. It should be noted that, in the examples and comparative examples, the specific conditions not specified are carried out according to the conventional conditions or the conditions recommended by the manufacturer, and the reagents or instruments not specified by the manufacturer are all conventional products that can be obtained by market purchase.

[0022] Example 1

[0023] 1.1 Preparation of the electrolyte:

[0024] In a glove box filled with nitrogen (O2<1 ppm, H2O<1 ppm), a mixed solvent obtained by mixing ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), and diethyl carbonate (DEC) in a mass ratio of 2:1:5:2 was used as an organic solvent, and then compound 1 was added to obtain a mixed solution. The mixed solution was sealed, placed in a quick-freezing chamber (-4°C), and frozen for 2 h. Then, lithium hexafluorophosphate and lithium bisfluorosulfonylimide were slowly added to the mixed solution in a glove box filled with nitrogen (O2<1 ppm, H2O<1 ppm), and the mixture was uniformly mixed to obtain an electrolyte.

[0025] 1.2 Preparation of the positive electrode sheet

[0026] The ternary material LiNi 0.8 Co 0.1 Mn 0.1 Zr 0.03 O2, a conductive agent SuperP, a binder PVDF, and carbon nanotubes (CNT) were uniformly mixed in a mass ratio of 96.5:1.5:1:1 to prepare a lithium ion battery positive electrode slurry with a certain viscosity, which was coated on an aluminum foil current collector at a coating amount of 324 g / m 2 After drying at 85°C, cold pressing was performed; then, edge cutting, sheet cutting, and striping were performed, and after striping, the strips were dried at 85°C for 4 h under vacuum conditions, and the tabs were welded to prepare a lithium ion battery positive electrode sheet meeting the requirements.

[0027] 1.3 Preparation of the negative electrode sheet

[0028] After artificial graphite and silicon were mixed in a mass ratio of 90:10, a slurry was prepared by mixing the mixture with a conductive agent SuperP, a thickening agent CMC, and a binder SBR (styrene-butadiene rubber emulsion) in a mass ratio of 95:1.5:1.0:2.5, and then the mixed slurry was coated on both sides of a copper foil, and after drying and rolling, a negative electrode sheet was obtained, and a lithium ion battery negative electrode sheet meeting the requirements was prepared.

[0029] 1.4 Preparation of the lithium ion battery

[0030] The positive electrode sheet, the negative electrode sheet, and the separator prepared according to the above process were stacked to prepare a lithium ion battery with a thickness of 4.7 mm, a width of 55 mm, and a length of 60 mm, and the battery was vacuum baked at 75°C for 10 h, and then the above electrolyte was injected. After standing for 24 h, the battery was charged to 4.45 V at a constant current of 0.1 C (180 mA), and then charged to a current of 0.05 C (90 mA) at a constant voltage of 4.45 V; then, the battery was discharged to 3.0 V at 0.2 C (180 mA), and the above charging and discharging was repeated twice, and finally, the battery was charged to 3.8 V at 0.2 C (180 mA) to complete the preparation of the lithium ion battery.

[0031] The composition and content of the electrolytes in Examples 1-19 and Comparative Examples 1-8 are shown in Table 1. The preparation processes of the lithium-ion battery electrolytes, positive electrode sheets, negative electrode sheets, and lithium-ion batteries in Examples 1-19 and Comparative Examples 1-8 are the same as those in Example 1. The additives were added along with the additives.

[0032] Table 1. Composition of the electrolytes in the examples and comparative examples.

[0033]

[0034]

[0035]

[0036] The lithium-ion batteries prepared in Examples 1-19 and Comparative Examples 1-8 were subjected to high-temperature storage performance tests, high-temperature cycle performance tests, room-temperature fast-charge cycle performance tests, and low-temperature performance tests under the following conditions. The results are shown in Table 2.

[0037] (1) High-temperature storage performance test

[0038] Under normal temperature (25℃) conditions, the lithium-ion battery was subjected to one 0.5C / 0.5C charge and discharge cycle (battery discharge capacity recorded as C0), with an upper limit voltage of 4.4V. Then, the battery was charged to 4.4V 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 the battery thickness was measured (thickness recorded as D1). The battery was placed in a 25℃ environment and discharged at 0.5C (discharge capacity recorded as C1). The lithium-ion battery was then subjected to one more 0.5C / 0.5C charge and discharge cycle under normal temperature (25℃) conditions (battery discharge capacity recorded as C2), with an upper limit voltage of 4.4V. The capacity retention rate, capacity recovery rate, and thickness expansion rate were calculated.

[0039] Capacity retention rate = (C1 / C0) * 100%

[0040] Capacity recovery rate = (C2 / C0) * 100%

[0041] Thickness expansion rate = (D1 / D0) * 100%

[0042] (2) Room temperature cycling performance test

[0043] Under normal temperature (25℃) conditions, a lithium-ion battery is subjected to one 1.0C / 1.0C charge and discharge cycle (battery discharge capacity is C0), with an upper limit voltage of 4.4V. Then, under normal temperature conditions, it is subjected to 500 cycles of 4.0C / 1.0C charge and discharge (battery discharge capacity is C1), and the capacity retention rate is calculated.

[0044] Capacity retention rate = (C1 / C0) * 100%

[0045] (3) High temperature cycle test

[0046] Under over-temperature (45°C) condition, the lithium ion battery was charged and discharged once at 1.0C / 1.0C (battery discharge capacity was C0) with upper limit voltage of 4.4V, then charged and discharged at 1.0C / 1.0C for 400 cycles (battery discharge capacity was C1) under normal temperature condition, and the capacity retention rate was calculated.

[0047] Capacity retention rate = (C1 / C0) * 100%

[0048] (4) Low temperature performance test

[0049] Under normal temperature (25°C) condition, the lithium ion battery was charged and discharged once at 0.5C / 0.5 (battery cut-off voltage was 3.0V, discharge capacity was C0) with upper limit voltage of 4.4V (cut-off current was 0.05C). Then the battery was charged to 4.4V (cut-off current was 0.05C) at 0.5C under normal temperature (25°C) condition, and then the battery was transferred to -20°C condition for 4h, and discharged at 0.5C to 3.0V, discharge capacity was C1, and the capacity retention rate was calculated.

[0050] Capacity retention rate = (C1 / C0) * 100%

[0051] Table 2 Test results of lithium ion battery performance

[0052]

[0053]

[0054] From the results of Table 2, compared with Comparative Examples 1-8, the comprehensive performance of Examples 1-19 is better. This is because the electrolyte of Examples 1-19 contains compound A, which is a bicyclic ether ketone compound, and thus has a relatively low oxidation potential and viscosity. The low potential characteristics of the electrolyte can be oxidized before the solvent to form a relatively thin interface layer on the electrode surface, which can reduce the ion transport path and improve the gas production problem of the battery under high voltage. In addition, the interface layer is not prone to shrinkage at low temperature, which can maintain the lithium ion transport channel at low temperature to improve the low temperature (such as -20°C) performance of the lithium ion battery. The low viscosity characteristics are also conducive to the rapid migration of ions under fast charging conditions, which can support the fast charging characteristics of the secondary battery. Furthermore, compound A has a double oxygen-containing heterocyclic structure, which can complex the residual alkali on the surface of the high-nickel ternary positive electrode material, thereby reducing the interface side reaction of the battery during the cycle and storage process, effectively inhibiting the decomposition of the SEI film interface, and further improving the high temperature storage and high temperature cycle performance of the secondary battery.

[0055] Although Comparative Example 5-8 contains compound 7 similar to compound A, it can not be able to better solve the problems of easy gas production, SEI film decomposition and the like of high nickel ternary positive electrode material due to the too low oxidation potential of the substance and the poor stability of the oxidation product, so the comprehensive performance is poor.

[0056] It can be known from the comparison of Example 7 and Example 13-16 that the addition of an additive on the basis of compound A can further improve the high-temperature storage performance, high-temperature cycle performance and low-temperature performance of the lithium ion battery.

[0057] It can be known from the comparison of Example 2 and Example 10-11 that the electrochemical comprehensive performance of the battery is better when the electrolyte salt is mixed with LiPF6 and LiFSI, which is because LiFSI has better thermal stability and power characteristics, but has corrosion problem to the current collector, and LiPF6 can passivate the current collector, thereby alleviating the negative effect of LiFSI on the current collector, and the battery performance is exerted when LiPF6 and LiFSI are mixed.

[0058] It can be known from the comparison of Example 17-19 that when VC / FEC mixed additive is used on the basis of a certain content of compound A, the high-temperature performance and low-temperature performance of the lithium ion battery can be greatly improved, and the expansion rate is further improved, which is because VC, FEC and compound A form a multi-component interface, which further improves the electrolyte-electrode interface stability and lithium ion transmission characteristics, and the battery performance is significantly improved.

[0059] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application, although the present application has been described in detail with reference to the preferred embodiments, but it is not limited to the examples listed in the embodiments, and those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A lithium-ion battery, comprising a positive electrode material, a negative electrode material, and an electrolyte, characterized in that, 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-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. The electrolyte includes an electrolyte salt, an organic solvent, and an additive. The additive includes a compound A shown in Structural Formula I, where R1 to R4 are each independently C═R5 or CR6R7, R5 is an alkylene group, and R6 to R7 are each independently hydrogen, a halogen, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, or a cyano group. The viscosity of the compound A is 1 to 3 mba / cm.

2. The lithium-ion battery as described in claim 1, characterized in that, R1 to R4 are each independently C=CH2 or CR6R7, and R6 to R7 are each independently hydrogen, C1 to C3 alkyl, C2 to C3 alkenyl or C2 to C3 alkynyl.

3. The lithium-ion battery as described in claim 1, characterized in that, Compound A is selected from at least one of compounds 1 to 6:

4. The lithium-ion battery as described in claim 1, characterized in that, The mass of compound A accounts for 0.1% to 5.0% of the total mass of the electrolyte.

5. The lithium-ion battery as described in claim 1, characterized in that, The electrolyte salt includes at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium methanesulfonate, lithium trifluoromethanesulfonate, lithium fluorosulfonate, lithium dioxalate borate, lithium difluorooxalate borate, lithium difluorophosphate, lithium difluorobis(oxalate) phosphate, and lithium lower aliphatic carboxylic acids.

6. The lithium-ion battery as described in claim 1, characterized in that, The electrolyte salt accounts for 5-25% of the total mass of the electrolyte solution.

7. The lithium-ion battery as described in claim 1, characterized in that, The organic solvent includes at least one of carbonates, carboxylic esters, and ether compounds.

8. The lithium-ion battery as described in claim 1, characterized in that, It also includes additives selected from vinylene carbonate, vinylene ethylene carbonate, fluoroethylene carbonate, vinyl sulfite, 1,3-propanesulfonate lactone, 1,3-propenesulfonate lactone, 1,4-butanesulfonate lactone, vinyl sulfate, succinic anhydride, maleic anhydride, 2-methylmaleic anhydride, methyl carbonate-2-propynyl ester, tetraethylenesilane, triallyl isocyanurate, hexamethylene diisocyanate, o-phenanthroline, and terephthalic acid. At least one of the following: ester, 2,4-toluene diisocyanate, N-phenylbis(trifluoromethanesulfonyl)imide, vinyl disulfate, phenyl methanesulfonate, propylene dispironate, hydroquinone difluorosulfonate, triallyl phosphate, triargyl phosphate, 2,4-butane sulpholol, isocyanate ethyl methacrylate, methylene disulfonate, tri(trimethylsilane)borate, tri(trimethylsilane) phosphate, and tri(vinyldimethylsilane) phosphate.

Images