Lithium ion battery electrolyte and lithium ion battery thereof

Abstract

The lithium ion battery electrolyte comprises a non-aqueous organic solvent, a lithium salt and an additive, the non-aqueous organic solvent comprises a carbonic ester compound, the structure of the additive is shown as a formula 1: # imgabs0 #, R1 to R3 are independently selected from hydrogen, alkyl, alkenyl and alkynyl, X, Y and Z are independently selected from C = O, S = O and O = S = O, and X, Y and Z are independently selected from hydrogen, alkyl, alkenyl and alkynyl. And at least one of X, Y and Z is O = S = O. The lithium ion battery electrolyte comprises the additive shown in the formula 1, the additive is high in oxidation resistance, an inert interface (SEI) containing nitrogen, sulfur and the like can be formed on the negative electrode side, and the SEI has the excellent ion transmission characteristic and has the good interface stability under the high-temperature and high-voltage condition; therefore, the lithium ion battery disclosed by the invention has relatively good low-temperature performance, high-temperature performance and quick charge characteristic under high voltage.

Description

Technical Field

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

[0002] Lithium-ion batteries have been widely used in 3C electronic products (such as smartphones and tablets), power tools, electric vehicles, aerospace and other fields due to their high operating voltage, high energy density, long service life, wide operating temperature range and environmental protection characteristics. As users' requirements for battery performance increase, especially for portable electronic devices, the pursuit of thinner and lighter designs and higher energy density has become the main trend in the development of battery technology.

[0003] In order to extend the battery life after charging, battery manufacturers and researchers are constantly working to improve the volumetric energy density of batteries. The most economical and effective way is to increase the charging cut-off voltage of the positive active material in the battery. However, increasing the charging cut-off voltage of the positive material will bring certain negative effects. For example, the high-voltage positive active material has strong oxidizing properties when it is lithium-deficient, and the electrolyte is easily oxidized and decomposed, causing the battery cell to produce gas and expand under high temperature conditions, increase impedance, and rapidly decay in capacity and performance. In addition, under low temperature conditions, the solid electrolyte interface layer (SEI) formed at the interface between the positive electrode material and the electrolyte of existing lithium-ion batteries becomes more stable but also thicker, increasing the resistance to electron transmission, which makes the discharge efficiency of lithium-ion batteries very low at low temperatures, which also limits the application range of lithium-ion batteries.

[0004] Therefore, there is an urgent need for a lithium ion battery electrolyte and a lithium ion battery thereof to solve the deficiencies of the prior art problems. Summary of the invention

[0005] In view of the above problems, an object of the present invention is to provide a lithium ion battery electrolyte and a lithium ion battery thereof, wherein the lithium ion battery electrolyte can improve the high temperature, low temperature and fast charging performance of the lithium ion battery.

[0006] To achieve the above objectives, the first aspect of the present invention provides a lithium ion battery electrolyte, comprising a non-aqueous organic solvent, a lithium salt and an additive, wherein the non-aqueous organic solvent comprises a carbonate compound, and the structure of the additive is shown in Formula 1:

[0007]

[0008] Wherein, R1-R3 are each independently selected from hydrogen, alkyl, alkenyl, alkynyl, X, Y, Z are each independently selected from C=O, S=O, O=S=O, and at least one of X, Y, Z is O=S=O.

[0009] Compared with the prior art, the lithium-ion battery electrolyte of the present invention includes an additive shown in Formula 1, which has strong oxidation resistance. At the same time, the additive can form an inert interface (SEI) containing nitrogen, sulfur, etc. on the negative electrode side. The interface will not dissolve in carbonate solvents under high temperature and high voltage conditions, thereby improving the stability of the negative electrode interface, thereby improving the high temperature performance of the lithium-ion battery under high voltage. In addition, the nitrogen- and sulfur-containing SEI has excellent ion transport characteristics, which can greatly improve the low temperature and fast charging characteristics of the lithium-ion battery. Therefore, the lithium-ion battery electrolyte of the present invention is applied to lithium-ion batteries, and the lithium-ion batteries have good low temperature performance, high temperature performance and fast charging characteristics under high voltage.

[0010] Further, R1 to R3 of the present invention are each independently selected from hydrogen, C1 to C8 alkyl, C2 to C6 alkenyl, and C2 to C6 alkynyl. Specifically, C1 to C8 alkyl may be, but not limited to, at least one of methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, and cyclohexyl; C2 to C6 alkenyl may be, but not limited to, vinyl, propenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, and 5-hexenyl; C2 to C6 alkynyl may be, but not limited to, ethynyl, propynyl, 1-butynyl, 2-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 1-hexynyl, 2-hexynyl, and 3-hexynyl. Preferably, R1 to R3 are each independently selected from hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl and cyclohexyl.

[0011] Furthermore, the additive of the present invention is selected from at least one of Compounds 1 to 6:

[0012]

[0013] Furthermore, the mass percentage of the additive of the present invention in the lithium-ion battery electrolyte is 0.1-5%. Specifically, the content of the additive may be, but is not limited to, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%. If the content is lower than 0.1%, it is insufficient to form an effective interface film, and if the content is higher than 5%, the interface film may be too thick, which in turn increases the internal resistance. Preferably, the mass percentage of the additive in the lithium-ion battery electrolyte is 0.1-2%.

[0014] Further, the lithium salt of the present invention 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 methanesulfonate (LiMS), lithium trifluoromethylsulfonate, lithium fluorosulfonate, lithium bis(oxalate borate) (LiBOB), lithium difluorooxalate borate (LiDFOB), lithium difluorophosphate (LiPO2F2), lithium difluorobis(oxalate phosphate) (LiDFOP), lithium diphosphate (Li2HPO4) and lower aliphatic lithium carboxylate. The lower aliphatic lithium carboxylate may be, but is not limited to, lithium acetate and lithium propionate. Lithium hexafluorophosphate has the characteristics of high conductivity, good electrochemical stability and good compatibility with graphite negative electrode, so the electrolyte lithium salt of the present invention is preferably lithium hexafluorophosphate.

[0015] Furthermore, the non-aqueous organic solvent of the present invention also includes at least one of a carboxylate compound and an ether compound. Carbonate, carboxylate and ether compounds generally have good lithium salt solubility, which can ensure that the concentration of lithium ions in the electrolyte is sufficiently high, thereby providing good conductivity. In addition, carbonate compounds generally have a higher boiling point, which helps to improve the thermal stability of the electrolyte; carboxylate compounds have a lower viscosity, which can improve the fluidity and wettability of the electrolyte; ether compounds can remain liquid over a wider temperature range, which is beneficial to the use of batteries in high and low temperature environments. Therefore, by reasonably selecting and proportioning these different types of non-aqueous organic solvents, the conductivity and cycle life of lithium-ion batteries can be optimized.

[0016] Further, the carbonate compounds of the present invention include cyclic carbonates and chain carbonates. Specifically, the cyclic carbonates may be, but are not limited to, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), pentylene carbonate, vinylene carbonate (VC) or their derivatives; chain carbonates include, but are not limited to, dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and propylene carbonate.

[0017] Furthermore, the carboxylate compounds of the present invention include at least one of cyclic carboxylates and chain carboxylates, and the cyclic carboxylates specifically include but are not limited to at least one of γ-butyrolactone (GBL), γ-valerolactone (GVL), and δ-valerolactone (DVL); the chain carboxylates specifically include but are not limited to methyl acetate (MAC), ethyl acetate (EA), propyl acetate (PA), butyl acetate (BA), propyl propionate (PP), and butyl propionate (BP).

[0018] Furthermore, the ether compounds of the present invention include cyclic ethers or chain ethers. The cyclic ethers may specifically 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); the chain ethers may specifically include but are not limited to dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

[0019] Furthermore, the lithium ion battery electrolyte of the present invention also includes an auxiliary agent, which is selected from vinylene carbonate (VC), vinylene carbonate (VEC), fluoroethylene carbonate (FEC), vinyl sulfite (ES), 1,3-propane sultone (PS), 1,3-propylene sultone (PES), 1,4-butane sultone (BS), vinyl sulfate (DTD), succinic anhydride (SA), maleic anhydride (MA), 2-methylmaleic anhydride (MMA), methyl carbonate-2-propynyl ester (MPC), tetravinylsilane (TES), triallyl isocyanurate (TAIC), hexamethylene diisocyanate (Isocyanurate), 1,3-propane sultone (PS), 1,3-propene sultone (PES), 1,4-butane sultone (BS), 1,3-propene sultone (PES), 1,3-propene sultone (PES), 1,4-butane sultone (BS), 1,3-propene sultone (DTD), 1,3-propene sultone (PS ... At least one of ester (HDI), o-phenanthroline, p-phenylene diisocyanate (TDI), 2,4-toluene diisocyanate (MDI), N-phenyl bis (trifluoromethanesulfonyl) imide (LiTFSI), divinyl sulfate (DES), phenyl methanesulfonate (BMS), dispiro propylene sulfate (DPS), hydroquinone difluorosulfonate, triallyl phosphate (TAP), tripropargyl phosphate (TPP), 2,4-butane sultone (BES), isocyanoethyl methacrylate, methylene disulfonate, tris (trimethylsilyl) borate, tris (trimethylsilyl) phosphate, tris (vinyl dimethylsilyl) phosphate. By rationally selecting and proportioning the additives, the high temperature performance and low temperature performance of lithium-ion batteries can be significantly improved.

[0020] Furthermore, the mass percentage of the auxiliary agent of the present invention in the lithium ion battery electrolyte is 0.1-5%. For example, the content of the auxiliary agent can be, but is not limited to, 0.1%, 0.6%, 0.8%, 1.2%, 1.6%, 2%, 2.6%, 3.2%, 3.6%, 4%, 4.5%, 5%.

[0021] Correspondingly, a second aspect of the present invention provides a lithium-ion battery, comprising a positive electrode, a negative electrode, and the lithium-ion battery electrolyte mentioned above.

[0022] Compared with the prior art, the lithium ion battery electrolyte of the lithium ion battery of the present invention includes an additive shown in Formula 1, which has strong oxidation resistance and can form an inert interface (SEI) containing nitrogen, sulfur, etc. on the negative electrode side. The SEI has excellent ion transport properties and has good interface stability under high temperature and high voltage conditions. Therefore, the lithium ion battery of the present invention has good low temperature performance, high temperature performance and fast charging characteristics under high voltage.

[0023] Further, the active material of the positive electrode of the present invention includes at least one of a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide and their respective modified compounds. The active material of the positive electrode of the present invention is not limited to these types, and other traditional materials that can be used as active materials for the positive electrode of the battery can also be used. These positive electrode active materials can be used alone or in combination of two or more. Specifically, examples of lithium-containing phosphates with an olivine structure may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Specifically, lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (structure such as LiNi x Co y Mn 1-x-y M z O2, wherein 0.6≤x<0.9, x+y<1, 0≤z<0.08, M is at least one of Al, Mg, Zr and Ti).

[0024] Furthermore, the maximum charging voltage of the lithium ion battery of the present invention is 4.45 V. Since the substance shown in Formula 1 is used as an additive in the lithium ion battery electrolyte of the present invention, the SEI film formed by the additive still has good interface stability at high temperature and at a high voltage of 4.45 V.

[0025] Furthermore, the active material of the negative electrode of the present invention includes 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 may include graphite, hard carbon, soft carbon, graphene, mesophase carbon microspheres, etc.; the silicon-based negative electrode may include silicon materials, silicon oxides, silicon-carbon composite materials and silicon alloy materials, etc.; the tin-based negative electrode may include tin, tin carbon, tin oxygen, tin metal compounds; the lithium negative electrode may include metallic lithium or lithium alloys, wherein the lithium alloy may specifically be at least one of lithium silicon alloys, lithium sodium alloys, lithium potassium alloys, lithium aluminum alloys, lithium tin alloys and lithium indium alloys. DETAILED DESCRIPTION

[0026] In order to more clearly explain the purpose of the present invention, technical solutions and beneficial effects thereof, further description will be given below by specific examples. It should be noted that in the examples and reference examples, if no experimental conditions are particularly indicated, the conditions recommended by the standard operating procedures or manufacturers should be followed. In addition, if the specific supplier of the reagents or equipment used is not specified, then these materials and instruments are all products that can be routinely purchased on the market.

[0027] Example 1

[0028] This embodiment provides a method for preparing a lithium ion battery, the steps comprising:

[0029] (1) LiNi 0.8 Co 0.1 Mn 0.1 Zr 0.03 O2, conductive agent SuperP, adhesive PVDF and carbon nanotubes (CNT) are mixed evenly in a mass ratio of 96.5:1.5:1:1 to form a lithium-ion battery positive electrode slurry with a certain viscosity, which is coated on the aluminum foil for current collector. The coating amount is 324g / m 2 , dried at 85°C and then cold pressed; then trimmed, cut into pieces, and slit, and then dried at 85°C for 4 hours under vacuum conditions, and the tabs were welded to make positive plates that meet the requirements;

[0030] (2) artificial graphite and silicon are mixed in a mass ratio of 90:10, and then mixed with a conductive agent SuperP, a thickener CMC, and an adhesive SBR (styrene-butadiene rubber latex) in a mass ratio of 95:1.5:1.0:2.5 to make a slurry, which is mixed evenly, and the mixed slurry is applied on both sides of a copper foil, and then dried and rolled to obtain a negative electrode sheet, thereby making a negative electrode sheet that meets the requirements;

[0031] (3) In a glove box filled with nitrogen (O2 <1ppm, H2O <1ppm), ethylene carbonate (EC), ethyl methyl carbonate (EMC), butylene carbonate (BC), propylene carbonate (PC), and butyl acetate (BA) are mixed in a mass ratio of 5:4:2:5:3 to obtain a mixed solvent as a non-aqueous organic solvent, and then additives and auxiliary agents are added to obtain a mixed solution. The mixed solution is sealed and packaged and placed in a quick freezer (-4°C) for 2 hours, then taken out, and lithium hexafluorophosphate (LiPF6) is slowly added to the mixed solution in a glove box filled with nitrogen (O2 <1ppm, H2O <1ppm). After mixing evenly, a lithium ion battery electrolyte is prepared;

[0032] (4) The positive electrode sheet, negative electrode sheet and separator are laminated to form a lithium-ion battery with a thickness of 4.7 mm, a width of 55 mm and a length of 60 mm. The battery is vacuum-baked at 75°C for 10 h and the lithium-ion battery electrolyte is injected. After standing for 24 h, the battery is charged to 4.45 V at a constant current of 0.1 C (180 mA), and then charged at a constant voltage of 4.45 V until the current drops to 0.05 C (90 mA); then discharged to 3.0 V at 0.2 C (180 mA), and the charge and discharge are repeated twice. Finally, the battery is charged to 3.8 V at 0.2 C (180 mA) to obtain a lithium-ion battery.

[0033] The formulas of the lithium ion battery electrolytes of Examples 1 to 16 and Comparative Examples 1 to 4 are shown in Table 1, wherein the preparation processes of the lithium ion battery electrolytes, positive electrode sheets, negative electrode sheets, and lithium ion batteries of Examples 2 to 16 and Comparative Examples 1 to 4 are exactly the same as those of Example 1.

[0034] Table 1 Compositions of the lithium ion battery electrolytes of the embodiments and comparative examples

[0035]

[0036]

[0037] The lithium ion batteries prepared in Examples 1 to 16 and Comparative Examples 1 to 4 were subjected to high temperature storage performance test, high temperature cycle performance test, room temperature cycle performance test, and low temperature performance test under the following conditions. The results are shown in Table 2.

[0038] High temperature storage performance test :

[0039] 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 4.45V, and then the battery was charged to 4.45V 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 4.45V, and the capacity retention rate, capacity recovery rate and thickness expansion rate were calculated.

[0040] Capacity retention rate = (C1 / C0) × 100%

[0041] Capacity recovery rate = (C2 / C0) × 100%

[0042] Thickness expansion ratio = (D1 / D0) × 100%

[0043] Normal temperature cycle performance test :

[0044] At room temperature (25°C), the lithium-ion battery is charged and discharged at 1.0C / 1.0C once (the battery discharge capacity is C0) with an upper voltage of 4.45V, and then charged and discharged at 1.0C / 1.0C for 500 cycles at room temperature (the battery discharge capacity is C1), and the capacity retention rate is calculated.

[0045] Capacity retention rate = (C1 / C0) × 100%

[0046] High temperature cycle performance test :

[0047] Under high temperature (50°C) conditions, the lithium-ion battery is charged and discharged at 1.0C / 1.0C once (the battery discharge capacity is C0) with an upper voltage of 4.45V, and then charged and discharged at 1.0C / 1.0C for 400 cycles at room temperature (the battery discharge capacity is C1), and the capacity retention rate is calculated.

[0048] Capacity retention rate = (C1 / C0) × 100%

[0049] Low temperature performance test :

[0050] At room temperature (25°C), the lithium-ion battery is charged and discharged at 0.5C / 0.5 (battery cut-off voltage is 3.0V, discharge capacity is C0), and the upper limit voltage is 4.45V (cut-off current 0.05C). Then the battery is fully charged to 4.45V (cut-off current 0.05C) at 0.5C at room temperature (25°C), and then the battery is transferred to -20°C and left for 4 hours, and discharged to 3.0V at 0.5C, and the discharge capacity is C1. The capacity retention rate is calculated.

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

[0052] Fast charging performance test:

[0053] At room temperature (25°C), the lithium-ion battery is charged and discharged at 4.0C / 1.0C once (the battery discharge capacity is C0) with an upper voltage of 4.45V, and then charged and discharged at 4.0C / 1.0C for 300 cycles at room temperature (the battery discharge capacity is C1), and the capacity retention rate is calculated.

[0054] Capacity retention rate = (C1 / C0) × 100%

[0055] Table 2 Lithium-ion battery performance test results

[0056]

[0057] It can be seen from Table 2 that compared with Comparative Examples 1 to 4, the lithium-ion batteries of Examples 1 to 6 have better low-temperature performance, high-temperature performance and fast-charging characteristics at a high voltage of 4.45V. This is because the lithium-ion battery electrolyte of the lithium-ion batteries of Examples 1 to 6 includes the additive shown in Formula 1, which has strong oxidation resistance. At the same time, the additive can form an inert interface (SEI) containing nitrogen, sulfur, etc. on the negative electrode side. The interface will not dissolve in carbonate solvents under high temperature and high voltage conditions, thereby improving the stability of the negative electrode interface, thereby improving the high-temperature performance of the lithium-ion battery under high voltage. In addition, the nitrogen- and sulfur-containing SEI has excellent ion transport characteristics, which can greatly improve the low temperature and fast charging characteristics of the lithium-ion battery. Therefore, the lithium-ion battery electrolyte of the present invention is applied to lithium-ion batteries, and the lithium-ion batteries have good low-temperature performance, high-temperature performance and fast charging characteristics at high voltage.

[0058] By comparing Example 8 with Examples 10 to 13, it can be seen that on the basis of the additives, further introducing auxiliary agents can significantly improve the high temperature performance and low temperature performance of the lithium ion battery.

[0059] By comparing Examples 10 to 11 with Examples 14 to 16, it can be seen that on the basis of the additives, when VC / MA mixed additives are further introduced, the high temperature performance and low temperature performance of the lithium ion battery are greatly improved, and the expansion rate is further improved. This is because VC helps to form a uniform and stable SEI film on the surface of the negative electrode, and MA can reduce the viscosity of the electrolyte and improve the fluidity of the electrolyte at low temperatures. Therefore, when VC / MA mixed additives are introduced, the high temperature performance and low temperature performance of the lithium ion battery can be significantly improved.

[0060] 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 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 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 lithium-ion battery electrolyte, comprising a non-aqueous organic solvent, a lithium salt and an additive, wherein the non-aqueous organic solvent comprises a carbonate compound, characterized in that: The structure of the additive is shown in Formula 1: Wherein, R1-R3 are each independently selected from hydrogen, alkyl, alkenyl, alkynyl, X, Y, Z are each independently selected from C=O, S=O, O=S=O, and at least one of X, Y, Z is O=S=O.

2. The lithium ion battery electrolyte according to claim 1, characterized in that R1 to R3 are each independently selected from hydrogen, C1 to C8 alkyl, C2 to C6 alkenyl, and C2 to C6 alkynyl.

3. The lithium ion battery electrolyte according to claim 1, characterized in that The additive is selected from at least one of Compound 1 to Compound 6:

4. The lithium ion battery electrolyte according to claim 1, characterized in that The mass percentage of the additive in the lithium ion battery electrolyte is 0.1-5%.

5. The lithium ion battery electrolyte according to claim 1, characterized in that The lithium salt includes at least one of lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl imide), lithium bis(trifluoromethylsulfonyl imide), lithium methane sulfonate, lithium trifluoromethyl sulfonate, lithium fluorosulfonate, lithium bis(oxalatoborate), lithium difluorooxalatoborate, lithium difluorophosphate, lithium difluorobis(oxalatophosphate), lithium diphosphate and lithium lower aliphatic carboxylate.

6. The lithium ion battery electrolyte according to claim 1, characterized in that The non-aqueous organic solvent further comprises at least one of a carboxylate compound and an ether compound.

7. The lithium ion battery electrolyte according to claim 1, characterized in that: It also includes an auxiliary agent, which is selected from vinylene carbonate, vinylene carbonate, fluoroethylene carbonate, vinyl sulfite, 1,3-propane sultone, 1,3-propylene sultone, 1,4-butane sultone, vinyl sulfate, succinic anhydride, maleic anhydride, 2-methylmaleic anhydride, methyl carbonate-2-propynyl ester, tetravinylsilane, triallyl isocyanurate, hexamethylene diisocyanate, o-phenanthroline, p-phenylene diisocyanate, 2, At least one of 4-toluene diisocyanate, N-phenylbis(trifluoromethanesulfonyl)imide, vinyl bissulfate, phenyl methanesulfonate, vinyl bissulfate, bis-spiro-propylene sulfate, hydroquinone difluorosulfonate, triallyl phosphate, tripropargyl phosphate, 2,4-butane sultone, isocyanoethyl methacrylate, methylene disulfonate, tris(trimethylsilyl)borate, tris(trimethylsilyl)phosphate, and tris(vinyldimethylsilyl)phosphate.

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

9. The lithium ion battery according to claim 8, characterized in that The active material of the positive electrode includes at least one of an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and modified compounds thereof.

10. The lithium ion battery according to claim 8, characterized in that The maximum charging voltage of the lithium-ion battery is 4.45V.

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