High voltage electrolyte and lithium ion battery containing the same

Abstract

The application discloses a high-voltage electrolyte and a lithium ion battery containing the electrolyte. The high-voltage electrolyte comprises a lithium salt, an organic solvent and an additive. The organic solvent is a fluorodioxane derivative, and the fluorodioxane derivative has a structural general formula shown in formula I. R1 and R2 are independently selected from one or more than two of the following groups: -CF3, -CHF2, a halogen element, -H, -CH3 and -OH. The high-voltage electrolyte has high ion conductivity, cycle performance and oxidation stability, so that the lithium ion battery containing the high-voltage electrolyte has high long cycle capacity retention rate and can be stably cycled at a high voltage.

Description

Technical Field

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

[0002] The rapid development of electrochemical energy storage has led to the increasing use of lithium-ion batteries in scalable energy storage devices, particularly as a power source for new energy vehicles. With the rapid development of new energy vehicles, the performance requirements for lithium-ion batteries are gradually increasing. The pursuit of higher energy density, higher safety, and higher stability systems is the current development direction of lithium-ion batteries.

[0003] Improving the electrolyte of lithium-ion batteries is one of the more common solutions in the industry. Without affecting the overall performance and safety of the battery, especially when considering high-voltage and high-stability applications, by introducing fluorine into the solvent, the lithium-ion battery can ensure stable operation at high voltage.

[0004] However, the current fluorinated compounds used as organic solvents in high-voltage electrolyte solutions mostly adopt a fully fluorinated structure. In the formation of the solvated structure, there is no strong electron-withdrawing effect, and the inorganic component is reduced in the subsequent SEI formation process. In addition, the oxidative stability of the overall structure is still insufficient, making it impossible for lithium-ion batteries to operate stably at higher voltages. Summary of the Invention

[0005] In view of this, it is necessary to provide a high-voltage electrolyte in the present invention. Starting from the design of the electrolyte solvent, the high-voltage electrolyte introduces a fluorinated dioxetane derivative into the solvent. The fluorinated dioxetane derivative has a fully fluorinated and / or partially fluorinated structure, and utilizes a strong electron-withdrawing effect to form a SEI film rich in LiF inorganic components to ensure the stability of the electrode material; the partially fluorinated -CHF2 has a local dipole, which can ensure the interaction between molecules. At the same time, the fluorinated dioxetane derivative of the present invention has high oxidative stability, which can ensure the safe and stable operation of the lithium-ion battery at a higher voltage.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention first provides the use of a fluorodioxetane derivative as an organic solvent in the preparation of a high-voltage electrolyte. The fluorodioxetane derivative has a general structural formula shown in Formula I:

[0008]

[0009] Wherein, R1 and R2 are independently selected from one or more of the group -CF3, -CHF2, halogen elements, -H, -CH3, and -OH.

[0010] In a further embodiment, R1 and R2 are independently selected from the group -CF3 or -CHF2; preferably, R1 and R2 contain at least one group -CHF2.

[0011] In a further embodiment, the fluorodioxane derivative has a structure shown in Formula 1, Formula 2 or Formula 3:

[0012]

[0013] The present invention further provides a high-voltage electrolyte comprising a lithium salt, an organic solvent, and an additive, wherein the organic solvent is a fluorodioxetane derivative having a general structural formula shown in Formula I:

[0014]

[0015] Wherein, R1 and R2 are independently selected from one or more of the group -CF3, -CHF2, halogen elements, -H, -CH3, and -OH.

[0016] In a further embodiment, R1 and R2 are independently selected from the group -CF3 or -CHF2; preferably, R1 and R2 contain at least one group -CHF2.

[0017] In a further embodiment, the fluorodioxane derivative has a structure shown in Formula 1, Formula 2 or Formula 3:

[0018]

[0019] In a further embodiment, the lithium salt is selected from at least one of LiPF6, LiDFOB, LiCF3SO3, LiBETI, LiBF4, LiClO4, LiBOB, LiTFSI, and LiFSI.

[0020] In a further embodiment, the additive is selected from at least one of lithium hexafluorophosphate, lithium nitrate, 2-fluoropyridine, ethoxy (pentafluoro) cyclotriphosphazene, vinyl sulfate, vinylene carbonate, and fluoroethylene carbonate.

[0021] In a further embodiment, based on the total mass of the high-voltage electrolyte, the molar ratio of the lithium salt to the organic solvent is 0.5:1-1:1, and the mass fraction of the additive is 0.5-10%.

[0022] The present invention further provides a lithium-ion battery comprising a positive electrode containing a cathode active material, a negative electrode containing an anode active material, a separator, and an electrolyte, wherein the electrolyte is the high-voltage electrolyte described above;

[0023] Preferably, the cathode active material is selected from at least one of a lithiated transition metal phosphate having an olivine structure, a lithium ion embedded transition metal oxide having a layered structure, and a lithiated transition metal mixed oxide having a spinel structure;

[0024] Preferably, the anode active material is selected from at least one of carbonaceous materials, titanium oxide, silicon, lithium or lithium alloys.

[0025] The beneficial effects of the present invention are as follows:

[0026] The present invention proposes to use fluorinated dioxane derivatives as lithium ion battery electrolyte solvents. The structure of the fluorinated dioxane derivatives has a strong electron-withdrawing effect. In the formation of the solvation structure, an AGG-type solvation structure can be formed to form an inorganic component-rich SEI, which can improve the oxidation stability of the battery. In addition, the partially fluorinated -CHF2 has a dipole, which can ensure the interaction of molecules and enhance the Li + The solvation capacity of the electrolyte is excellent, showing high ionic conductivity, cycling performance and oxidation stability. In the detection of the electrolyte's own properties, this electrolyte shows high oxidation stability and conductivity.

[0027] The lithium-ion battery containing the high-voltage electrolyte exhibits a high long-cycle capacity retention rate at a high voltage of 4.8V or above, and because the fluorinated dioxane derivative of the present invention has high oxidation stability, it can ensure stable cycle operation of the battery at a higher voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The LSV test results of the lithium-ion batteries 1-3 prepared in Examples 1-3 are shown. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0031] The first aspect of the present invention provides the use of a fluorodioxetane derivative as an organic solvent in the preparation of a high-voltage electrolyte, wherein the fluorodioxetane derivative has the general structural formula shown in Formula I:

[0032]

[0033] wherein R1 and R2 are independently selected from one or more of the group consisting of -CF3, -CHF2, a halogen element, -H, -CH3, and -OH. Preferably, R1 and R2 are independently selected from the group consisting of -CF3 or -CHF2; more preferably, R1 and R2 are independently selected from the group consisting of -CF3 or -CHF2, and at least one of R1 and R2 is -CHF2.

[0034] Since the fluorinated dioxetane derivative contains -CF3 and / or -CHF2 groups in its structure, it has a strong electron-withdrawing effect and can improve the oxidation stability of the electrode material. The partially fluorinated -CHF2 has a local dipole that can ensure the interaction between molecules and improve the Li + The solvating ability of the organic solvent enables the lithium-ion battery containing the electrolyte prepared by the organic solvent to exhibit high voltage performance and high stability.

[0035] In some typical embodiments of the present invention, the fluorodioxane derivative has a structure shown in Formula 1, Formula 2 or Formula 3:

[0036]

[0037] A second aspect of the present invention provides a high-voltage electrolyte comprising a lithium salt, an organic solvent, and an additive, wherein the organic solvent is a fluorodioxetane derivative having a general structural formula shown in Formula I:

[0038]

[0039] Wherein, R1 and R2 are independently selected from one or more of the group -CF3, -CHF2, a halogen element, -H, -CH3, and -OH. Preferably, R1 and R2 are independently selected from the group -CF3 or -CHF2; preferably, at least one of R1 and R2 contains a -CHF2 group.

[0040] In some typical embodiments of the present invention, the fluorodioxane derivative has a structure shown in Formula 1, Formula 2 or Formula 3:

[0041]

[0042] Furthermore, some typical embodiments of the present invention also provide a method for preparing the fluorodioxane derivatives represented by Formula 1, Formula 2 or Formula 3, which are specifically as follows:

[0043] (1) Preparation of fluorodioxane derivatives as shown in Formula 1:

[0044] 20g of perfluoropinacol was dissolved in 60ml of dimethyl ether in a round-bottom flask, and 15.6g of 1,4-butanediol, 140g of ethylene carbonate, 8g of sodium hydroxide, and 200ml of tetrasitol were added. Under a nitrogen atmosphere, the suspension was heated to 140°C and stirred for 48h. It was then distilled three times under vacuum (approximately 65°C, 1kPa) to obtain a colorless liquid as the product, yielding the perfluorinated dioxane shown in Formula 1.

[0045] (2) Preparation of fluorodioxane derivatives as shown in Formula 2:

[0046] 20g of perfluoropinacol was dissolved in 60ml of dimethyl ether in a round-bottom flask, and 50g of 2-(2,2-difluoroethoxy)ethanol, 120g of 2,2-difluoroethoxy, 8g of sodium hydroxide, and 200ml of tetrasitol were added. Under a nitrogen atmosphere, the suspension was heated to 140°C and stirred for 48h, then distilled three times under vacuum to obtain a colorless liquid as the product, the structure of which is shown in Formula 2.

[0047] (3) Preparation of fluorodioxane derivatives as shown in Formula 3:

[0048] 20g of perfluoropinacol was dissolved in 60ml of dimethyl ether in a round-bottom flask, and 50g of 2-(2,2-difluoroethoxy)ethanol, 110g of 2,2-difluoroethoxy, 93g of ethyl p-toluenesulfonate, 8g of sodium hydroxide, and 200ml of tetrasitol were added. Under a nitrogen atmosphere, the suspension was heated to 140°C and stirred for 48h, then distilled three times under vacuum to obtain a colorless liquid as the product, the structure of which is shown in Formula 3.

[0049] It is understood that the preparation of the fluorodioxane derivatives herein can be prepared by a preparation method similar to that of Formula 1, Formula 2 or Formula 3, which will not be described in detail here.

[0050] In a further embodiment, the lithium salt described in the high-voltage electrolyte herein is not particularly limited, and any type of lithium salt conventionally used in the art can be used. In some specific embodiments of the present invention, specific examples of the lithium salt include, but are not limited to, at least one of LiPF6, LiDFOB, LiCF3SO3, LiBETI, LiBF4, LiClO4, LiBOB, LiTFSI, and LiFSI.

[0051] In a further embodiment, it can be understood that adding additives to the high-voltage electrolyte to impart corresponding functions to the electrolyte is a technical means well known to those skilled in the art. The specific type of additive added can be selected according to actual conditions without particular limitation. In some specific embodiments of some inventions, the additive is selected from at least one of lithium hexafluorophosphate, lithium nitrate, 2-fluoropyridine, ethoxy (pentafluoro) cyclotriphosphazene, vinyl sulfate, vinylene carbonate, and fluoroethylene carbonate.

[0052] In a further embodiment, the addition amounts of the organic solvent, lithium salt, and additives can be adjusted according to actual conditions without particular limitation. In some typical embodiments of the present invention, based on the total mass of the high-voltage electrolyte, the molar ratio of the lithium salt to the organic solvent is 0.5:1-1:1, and the mass fraction of the additive is 0.5-10%.

[0053] A third aspect of the present invention provides a lithium-ion battery comprising a positive electrode containing a cathode active material, a negative electrode containing an anode active material, a separator, and an electrolyte, wherein the electrolyte is the high-voltage electrolyte described in the second aspect of the present invention;

[0054] Preferably, the cathode active material is selected from at least one of a lithiated transition metal phosphate having an olivine structure, a lithium ion embedded transition metal oxide having a layered structure, and a lithiated transition metal mixed oxide having a spinel structure;

[0055] Preferably, the anode active material is selected from at least one of carbonaceous materials, titanium oxide, silicon, lithium or lithium alloys.

[0056] After testing, the lithium-ion battery prepared using the high-voltage electrolyte described in the second aspect of the present invention still has extremely high stability and excellent cycle performance at a high cut-off voltage (4.8V).

[0057] The present invention is described below by means of specific examples. It should be noted that the following specific examples are for illustrative purposes only and do not limit the scope of the present invention in any way. In addition, unless otherwise specified, methods without specific conditions or steps are conventional methods, and the reagents and materials used are all commercially available.

[0058] Example 1

[0059]

[0060] Preparation of electrolyte

[0061] In an argon glove box with a moisture content of ≤10 ppm, LiFSI was slowly added to an organic solvent having a structure as shown in Formula 1. After the LiFSI was completely dissolved, the additive LiNO3 was added and stirred to obtain electrolyte 1; wherein the molar ratio of LiFSI:organic solvent was 0.5:1, and the mass fraction of the additive LiNO3 was 1%.

[0062] Preparation of lithium-ion batteries

[0063] The positive electrode active material (NMC811), the conductive agent acetylene black, and the binder polytetrafluoroethylene were mixed in a mass ratio of NMC811: acetylene black: polytetrafluoroethylene = 95:3:2. After the mixing was completed, NMP was added and the mixture was thoroughly stirred to obtain a positive electrode slurry. The positive electrode slurry was evenly coated on an aluminum foil with a thickness of 15 μm and dried to obtain a positive electrode sheet.

[0064] The negative electrode active material (graphite), conductive agent acetylene black, binder CMC and plasticizer SBR were mixed in a mass ratio of graphite: acetylene black: CMC: SBR = 95:2:2:1, and stirred thoroughly to obtain a negative electrode slurry. The negative electrode slurry was evenly coated on a copper foil with a thickness of 9 μm, and dried to obtain a negative electrode sheet.

[0065] A soft-pack laminated battery is manufactured in a dry environment with a dew point temperature below -40°C. The positive electrode sheet, separator and graphite negative electrode sheet are stacked in order to ensure that the separator completely separates the positive and negative electrode sheets. The tabs are then encapsulated and welded with aluminum-plastic film to form a battery ready for liquid injection. Before liquid injection, the battery moisture content is baked to below 300 ppm, and electrolyte 1 is injected. After sealing, formation and volume separation, a lithium-ion battery 1 is obtained.

[0066] Example 2

[0067]

[0068] Preparation of electrolyte

[0069] The same implementation as in Example 1 was adopted, with the only difference being that the organic solvent used was an organic solvent having a structure as shown in Formula 2. An electrolyte solution 2 was prepared.

[0070] Preparation of lithium-ion batteries

[0071] The same implementation as in Example 1 was adopted, with the only difference being that the injected electrolyte was electrolyte 2. A lithium-ion battery 2 was prepared.

[0072] Example 3

[0073]

[0074] Preparation of electrolyte

[0075] The same implementation as in Example 1 was adopted, with the only difference being that the organic solvent used was an organic solvent having a structure as shown in Formula 3. An electrolyte solution 3 was prepared.

[0076] Preparation of lithium-ion batteries

[0077] The same implementation as in Example 1 was adopted, with the only difference being that the injected electrolyte was electrolyte 3. A lithium-ion battery 3 was prepared.

[0078] Example 4

[0079] Preparation of electrolyte

[0080] The same implementation as in Example 3 was adopted, except that the molar ratio of lithium salt to organic solvent in the electrolyte was 0.8:1, and the mass fraction of the additive LiNO 3 was 1%. Electrolyte 4 was prepared.

[0081] Preparation of lithium-ion batteries

[0082] The same implementation as in Example 3 was adopted, with the only difference being that the injected electrolyte was electrolyte 4. A lithium-ion battery 4 was prepared.

[0083] Example 5

[0084] Preparation of electrolyte

[0085] The same implementation as in Example 3 was adopted, except that the molar ratio of lithium salt to organic solvent in the electrolyte was 1:1, and the mass fraction of the additive LiNO 3 was 1%. Electrolyte 5 was prepared.

[0086] Preparation of lithium-ion batteries

[0087] The same implementation as in Example 3 was adopted, with the only difference being that the injected electrolyte was electrolyte 5. A lithium-ion battery 5 was prepared.

[0088] Example 6

[0089] Preparation of electrolyte

[0090] In an argon glove box with a moisture content of ≤10 ppm, LiPF6 was slowly added to an organic solvent having a structure as shown in Formula 3. After the LiPF6 was completely dissolved, the additive LiNO3 was added and stirred to obtain electrolyte 6; wherein the molar ratio of LiPF6:organic solvent was 0.8:1, and the mass fraction of the additive LiNO3 was 1%.

[0091] Preparation of lithium-ion batteries

[0092] The same implementation as in Example 1 was adopted, with the only difference being that the injected electrolyte was electrolyte 6. A lithium-ion battery 6 was prepared.

[0093] Example 7

[0094] Preparation of electrolyte

[0095] In an argon glove box with a moisture content of ≤10 ppm, LiPF6 was slowly added to an organic solvent having a structure as shown in Formula 3. After the LiPF6 was completely dissolved, the additive VC was added and stirred to obtain electrolyte 7; wherein the molar ratio of LiPF6:organic solvent was 0.8:1, and the mass fraction of the additive VC was 2%.

[0096] Preparation of lithium-ion batteries

[0097] The same implementation as in Example 1 was adopted, with the only difference being that the injected electrolyte was electrolyte 7. A lithium-ion battery 7 was prepared.

[0098] Example 8

[0099] Preparation of electrolyte

[0100] In an argon glove box with a moisture content of ≤10 ppm, LiTFSI was slowly added to an organic solvent having the structure shown in Formula 3. After the LiTFSI was completely dissolved, the additive FEC was added and stirred to obtain electrolyte 8. The molar ratio of LiTFSI:organic solvent was 0.8:1, and the mass fraction of the additive FEC was 2%.

[0101] Preparation of lithium-ion batteries

[0102] The same implementation as in Example 1 was adopted, with the only difference being that the injected electrolyte was electrolyte 8. A lithium-ion battery 8 was prepared.

[0103] Example 9

[0104] Preparation of electrolyte

[0105] In an argon glove box with a moisture content of ≤10 ppm, LiTFSI was slowly added to an organic solvent having the structure shown in Formula 3. After the LiTFSI was completely dissolved, 2-fluoropyridine was added as an additive, and the mixture was stirred evenly to obtain electrolyte 9. The molar ratio of LiTFSI:organic solvent was 0.8:1, and the mass fraction of the 2-fluoropyridine additive was 1%.

[0106] Preparation of lithium-ion batteries

[0107] The same implementation as in Example 1 is adopted, except that the injected electrolyte is electrolyte 9. A lithium-ion battery 9 is prepared.

[0108] Example 10

[0109] Preparation of electrolyte

[0110] In an argon glove box with a moisture content of ≤10 ppm, LiTFSI was slowly added to an organic solvent having the structure shown in Formula 1. After the LiTFSI was completely dissolved, the additive LiPF6 was added and stirred to obtain an electrolyte 10. The molar ratio of LiTFSI:organic solvent was 0.8:1, and the mass fraction of the additive LiPF6 was 1%.

[0111] Preparation of lithium-ion batteries

[0112] The same implementation as in Example 1 is adopted, with the only difference being that the injected electrolyte is the electrolyte 10. A lithium-ion battery 10 is prepared.

[0113] Comparative Example 1

[0114] Preparation of electrolyte

[0115] The same method as Example 1 was used, with the only difference being that the electrolyte had a different composition, with the solvent having a volume ratio of EC:EMC = 3:7. 1M LiPF6 was dissolved therein, and after complete dissolution, 2% by mass of VC was added to prepare electrolyte 11.

[0116] Preparation of lithium-ion batteries

[0117] The same implementation as in Example 1 is adopted, with the only difference being that the injected electrolyte is electrolyte 11. A lithium-ion battery 11 is prepared.

[0118] Comparative Example 2

[0119]

[0120] Preparation of electrolyte

[0121] In an argon glove box with a moisture content of ≤10 ppm, LiFSI was slowly added to an organic solvent having a structure as shown in Formula 4. After the LiFSI was completely dissolved, the additive LiNO3 was added and stirred evenly to obtain an electrolyte 12; wherein the molar ratio of LiFSI:organic solvent was 0.5:1, and the mass fraction of the additive LiNO3 was 1%.

[0122] Preparation of lithium-ion batteries

[0123] The same implementation as in Example 1 is adopted, with the only difference being that the injected electrolyte is the electrolyte 12. A lithium-ion battery 12 is prepared.

[0124] Comparative Example 3

[0125]

[0126] Preparation of electrolyte

[0127] In an argon glove box with a moisture content of ≤10 ppm, LiFSI was slowly added to an organic solvent having a structure as shown in Formula 5. After the LiFSI was completely dissolved, the additive LiNO3 was added and stirred evenly to obtain an electrolyte 13; wherein the molar ratio of LiFSI:organic solvent was 0.5:1, and the mass fraction of the additive LiNO3 was 1%.

[0128] Preparation of lithium-ion batteries

[0129] The same implementation as in Example 1 is adopted, with the only difference being that the injected electrolyte is electrolyte 13. A lithium-ion battery 13 is prepared.

[0130] The compositions and contents of the electrolytes in Examples 1-10 and Comparative Examples 1-3 are shown in Table 1.

[0131] Table 1 Electrolyte composition

[0132]

[0133] Performance Testing

[0134] (1) The lithium ion batteries 1-3 prepared in Examples 1-3 were subjected to LSV tests respectively.

[0135] The LSV test is a linear sweep voltammetry method that detects the voltage stability range of the electrolyte. This LSV test uses a glassy carbon electrode as the working electrode, a platinum wire as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The scanning range is 0-5.5V and the scanning rate is 0.1mV / s. The results are as follows Figure 1 shown.

[0136] from Figure 1 From the LSV data, it can be seen that the fully fluorinated dioxane derivative (-CF3) exhibits lower oxidation stability with a stable voltage of 4.7 V, while the partially fluorinated dioxane derivative (-CHF2) exhibits a higher oxidation potential (5.1 V).

[0137] (2) Lithium-ion battery cycle performance test

[0138] The lithium ion batteries of Examples 1-7 and Comparative Examples 1-3 after being filled were placed in a 25℃ normal temperature laboratory and connected with a charge-discharge tester, first charged to 4.8V at a constant current and constant voltage of 1C current, and the cutoff current was set to 0.01C; after 10min, discharged to 3.0V at a constant current of 1C, and the cycle charge-discharge test was carried out in this way, and the discharge capacity of each cycle was recorded, and the capacity retention rate of the lithium ion battery at the 100th week, the 200th week and the 300th week was calculated, wherein the cycle capacity retention rate of the lithium ion battery at the Nth week (%) = the discharge capacity at the Nth week / the discharge capacity at the first cycle x 100%, and the related comparison data are shown in Table 2.

[0139] Table 2: Performance test of lithium ion battery

[0140]

[0141] From the capacity retention rate comparison of Examples 1-10 and Comparative Examples 1-3, it can be seen that the organic solvent formed by the fluorodioxane derivative in the application has good stability at high voltage. Compared with Comparative Example 3 in which the cyclohexane structure is fully fluorinated, the fluorodioxane derivative in the application has a partial fluorination of -CHF2, which can fully ensure the interaction between molecules and form a high inorganic component SEI; and compared with the partially fluorinated organic solvent in Comparative Example 2, the fluorodioxane derivative in the application is more stable and can maintain long cycle stability at high voltage.

[0142] In the field, increasing the cutoff voltage plays a crucial role in improving the energy density of lithium ion batteries, therefore, the high-voltage electrolyte provided herein can provide a new idea for the design of high-energy-density lithium ion battery systems.

[0143] The technical features of the above-described embodiments can be combined in any manner, and to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the description.

[0144] The above-described embodiments only express several embodiments of the application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which are within the scope of the application. Therefore, the protection scope of the patent of the application should be subject to the appended claims.

Claims

1. A high voltage electrolyte comprising a lithium salt, an organic solvent and an additive, characterized in that: The organic solvent is a fluorodioxane derivative, and the fluorodioxane derivative has a structure shown in Formula 2 or Formula 3: 。 2. The high-voltage electrolyte according to claim 1, wherein The lithium salt is selected from at least one of LiPF6, LiDFOB, LiCF3SO3, LiBETI, LiBF4, LiClO4, LiBOB, LiTFSI, and LiFSI.

3. The high voltage electrolyte according to claim 1, wherein The additive is selected from at least one of lithium hexafluorophosphate, lithium nitrate, 2-fluoropyridine, ethoxy (pentafluoro) cyclotriphosphazene, vinyl sulfate, vinylene carbonate, and fluoroethylene carbonate.

4. The high voltage electrolyte according to claim 1, wherein Based on the total mass of the high-voltage electrolyte, the molar ratio of the lithium salt to the organic solvent is 0.5:1-1:1, and the mass fraction of the additive is 0.5-10%.

5. A lithium ion battery comprising a positive electrode containing a cathode active material, a negative electrode containing an anode active material, a separator and an electrolyte, characterized in that: The electrolyte is the high-voltage electrolyte according to any one of claims 1 to 4.

6. The lithium-ion battery according to claim 5, wherein The cathode active material is selected from at least one of a lithiated transition metal phosphate having an olivine structure, a lithium ion embedded transition metal oxide having a layered structure, and a lithiated transition metal mixed oxide having a spinel structure.

7. The lithium-ion battery according to claim 5, wherein The anode active material is selected from at least one of carbonaceous materials, titanium oxide, silicon, lithium, or lithium alloys.

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