Perfluoro wide-temperature electrolyte for lithium battery and lithium ion battery thereof

Abstract

The invention relates to a perfluoro wide-temperature electrolyte for a lithium battery and application thereof, the wide-temperature electrolyte comprises a lithium salt, an additive and a plurality of perfluoro mixed solvents, the electrolyte capable of stably working in a wide temperature range (-80-80 DEG C) is successfully constructed, and the excellent electrochemical performance of the lithium battery at the wide temperature is realized. The electrolyte additive disclosed by the invention mainly comprises one or more of hexafluoroisopropoxy cyclotriphosphazene, 3-(2, 2, 2-trifluoroethoxy) propionitrile, 3-(2, 2, 2-trifluoroethoxy) butyronitrile, 3, 4-fluoroethylene sulfate and 4-trifluoromethyl-ethylene sulfate, and the fluorine-containing additive is good in flame retardant effect, moderate in viscosity, good in system compatibility, good in corrosion resistance and good in corrosion resistance. And a protective film can be formed on the surface of the positive electrode of the lithium battery, so that the high-pressure and high-temperature cycle performance of the battery is improved, the electrochemical performance of the battery is not influenced at all, the self-extinguishing time of the electrolyte is obviously shortened, the flame retardant property and the conductivity are excellent, the overcharge resistance of the lithium ion battery is also obviously improved, and the safety performance of the battery is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium battery electrolytes, and in particular relates to a perfluorinated wide-temperature electrolyte for lithium batteries. Background Art

[0002] As lithium batteries are increasingly used in various fields, their safety issues have gradually become prominent. The normal operating temperature range of lithium batteries is limited. If used or stored in a high temperature environment, the chemical reaction inside the battery will be accelerated, which will cause the battery to catch fire or explode. Carbonate-based solvents themselves have a high decomposition temperature, but in a high temperature environment, the thermal stability of carbonate-based solvents may be affected. When the battery works under high temperature conditions, an unstable interface film will be generated on the surface of the positive and negative electrodes, resulting in a sharp drop in battery capacity. At the same time, the electrolyte may undergo thermal decomposition, produce gas and harmful substances, and the battery performance will decline and even cause safety problems. Similarly, carbonate-based solvents will also experience rapid capacity decline at low temperatures. Wide-temperature lithium batteries play an important role in many fields with their excellent temperature adaptability, efficient energy storage, long cycle life, safety and reliability, so it is crucial to match a suitable wide-temperature electrolyte.

[0003] In recent years, many scholars have effectively reduced the flammability of electrolytes by designing flame retardant additives, thereby improving the safety of batteries. At present, the most commonly used are organophosphorus chemicals, such as trimethylphosphonic acid, triethyl phosphate, etc., which have been successfully used in lithium batteries. In addition, electrolyte solvents also play an important role in improving the stability of electrolytes. For example, fluorinated carbonate solvents have high oxidative stability with the cathode and good compatibility with the anode, respectively. Based on this, this patent proposes a new type of perfluorinated electrolyte suitable for wide-temperature lithium batteries. This electrolyte can exert excellent ionic conductivity and lithium ion migration number under the appropriate proportion of lithium salt, additive and solvent, and can match the electrode material at the same time. It is well known that moisture in the electrolyte can also affect the safety of the battery. Relevant researchers have added silicon-based additives to effectively remove trace water contained in the electrolyte.

[0004] Therefore, it is an urgent problem to find an electrolyte that meets both specific capacity and cycle performance, and a wide-temperature electrolyte that can discharge batteries at high and low temperatures, and improve the environmental adaptability and safety of batteries. This patent proposes a new type of perfluorinated wide-temperature electrolyte, which can effectively improve the performance and life of batteries under extreme conditions by optimizing the composition and concentration of the electrolyte, and has important practical value and market prospects. Summary of the invention

[0005] In order to improve the safety and electrochemical properties of batteries under extreme conditions, the present invention provides a perfluorinated wide-temperature electrolyte, which uses a perfluorinated solvent and a small amount of additives and has wide temperature adaptability. Fluorinated compounds have excellent electrochemical properties and can effectively broaden the electrochemical window of the electrolyte, so that it can be stably adapted to high-voltage lithium battery systems. In addition, the fluorine atoms in the solvent can weaken the binding energy between lithium ions and solvents, while enhancing the interaction between lithium ions and anions, forming a low-impedance interface film, promoting the reaction kinetics of the battery at the interface, and the stable circulation of the battery at low temperatures. At the same time, the high ignition point and boiling point of the perfluorinated solvent are conducive to its application at high temperatures.

[0006] The present invention also provides a method for preparing the above-mentioned perfluorinated wide-temperature electrolyte for lithium batteries, and applies it to lithium batteries.

[0007] In order to meet the specific requirements of the above electrolyte, the present invention provides a perfluorinated wide temperature electrolyte for lithium batteries, wherein the detailed experimental steps of the perfluorinated wide temperature electrolyte are as follows: First, add lithium salt into organic solvent and stir at 30-50 °C for 0.5-5 h; Additives are then added to the clarified liquid and mixed evenly to obtain the wide-temperature perfluorinated electrolyte for lithium batteries.

[0008] The concentration of the lithium salt is 0.1-1.5 mol / L. When the lithium salt concentration is too low, the conductivity of lithium ions will be low, resulting in poor low-temperature performance of the battery. When the concentration is too high, the viscosity of the electrolyte will be too high, affecting the migration speed of the electrolyte at low temperatures and increasing the cost of the electrolyte.

[0009] In the perfluorinated wide-temperature electrolyte, the lithium salt is one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium difluorobis(oxalate)phosphate, lithium difluorooxalate borate, and lithium bis(trimethylsilyl)amide. The lithium bis(fluorosulfonyl)imide and lithium bis(trifluoromethanesulfonyl)imide added in the present invention have excellent lithium ion transmission performance in a wide temperature range; the addition of lithium hexafluorophosphate can inhibit the corrosion of lithium bis(fluorosulfonyl)imide and lithium bis(trifluoromethanesulfonyl)imide to aluminum foil under high pressure; the addition of one or more of lithium difluorobis(oxalate)phosphate, lithium difluorooxalate borate, and lithium bis(trimethylsilyl)amide can improve the electrochemical stability of the battery.

[0010] In the perfluorinated wide temperature electrolyte, the first additive includes a fluorinated additive selected from one or more of hexafluoroisopropoxy cyclotriphosphazene, 3-(2,2,2-trifluoroethoxy) propionitrile, and 3-(2,2,2-trifluoroethoxy) butyronitrile, and the second additive is selected from one or more of 3,4-fluorovinyl sulfate and 4-trifluoromethyl-vinyl sulfate. The additive added in the present invention can form a low-impedance interface film at low temperatures, thereby enhancing the cycle performance of the battery under low temperature conditions. Generally speaking, the flame retardant properties of fluorine-containing additives are related to the F atom content, that is, the more fluorine content, the better the flame retardant properties. Cyclophosphazene solvent molecules as additives can achieve flame retardancy of the electrolyte when reaching a certain amount, thereby ensuring the high temperature performance of the battery.

[0011] In the low-temperature electrolyte, the solvent is one or more of fluoroethylene carbonate, fluoroacetonitrile, fluorobenzene, and trifluorobenzene. The fluoroethylene carbonate solvent of the present invention can dissolve lithium salts and promote interfacial film formation. Secondly, fluoroacetonitrile can have a high conductivity at low temperatures, which is conducive to lithium ion transmission. Fluorobenzene and trifluorobenzene can form anion-cation pairs with lithium ions, which accelerates the desolvation of lithium ions.

[0012] In summary, due to the interaction between lithium salts, solvents and additives, the wide-temperature electrolyte provided by the present invention can be used normally for a long time in the range of -80-80°C, specifically about 55°C or 70°C.

[0013] In some preferred cases, the solvent of the present declaration is a mixture, specifically a mixture of fluoroethylene carbonate, fluoroacetonitrile and fluorobenzene, wherein fluoroethylene carbonate, fluoroacetonitrile and fluorobenzene solvents are uniformly mixed in a volume ratio of 3:2-4:10-30 to obtain a perfluorinated solvent.

[0014] In the technical solution of the present invention, the operating temperature of the perfluorinated wide-temperature electrolyte is -80~80°C.

[0015] The beneficial effects of the present invention are as follows: 1. The wide temperature electrolyte provided by the present invention effectively improves the wide temperature stability and safety of the battery. The perfluorinated solvent is used as the base to keep the electrolyte in a liquid state at -80~80 ℃. It has a very low melting point and can effectively improve its ionic conductivity at low temperatures. At the same time, under the action of strong electron-withdrawing fluoride ions, the desolvation energy can be effectively reduced. 2. The present invention applies additives containing sulfur, fluorine and nitrogen groups to the electrolyte to enhance the stability of the electrolyte, thereby preventing the battery from burning or exploding in the event of overheating. At the same time, it can also react with trace water in the electrolyte to improve battery performance.

[0016] 3. The wide temperature electrolyte provided by the present invention significantly improves the wide temperature cycle performance of graphite and silicon-carbon negative electrodes.

[0017] 4. The wide-temperature electrolyte provided by the present invention significantly improves the stability of the lithium iron phosphate positive electrode material under a wide operating temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart for preparing the perfluorinated wide-temperature electrolyte of the present invention.

[0019] Figure 2 The linear sweep voltammetric curves of Example 1 and Comparative Example 1 of the perfluorinated wide temperature electrolyte of the present invention are shown. DETAILED DESCRIPTION

[0020] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the exact ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0021] In order to better understand the present invention, the content of the present invention is further described below in conjunction with embodiments and related drawings, but the content of the present invention is not limited to the following embodiments.

[0022] Example 1 First, add lithium salt into organic solvent and stir at 30-50 °C for 0.5-5 h; Additives are then added to the clarified liquid and mixed evenly to obtain the wide-temperature perfluorinated electrolyte for lithium batteries.

[0023] Figure 1 The flow chart of the preparation of the perfluorinated wide-temperature electrolyte is as follows: under anhydrous and oxygen-free conditions, fluoroethylene carbonate, fluoroacetonitrile and low-polarity solvent fluorobenzene are mixed in a volume ratio of 3:7:10 to obtain a perfluorinated solvent, and then 0.5 mol / L lithium bis(fluorosulfonyl)imide, 0.5 mol / L lithium bis(trifluoromethanesulfonyl)imide, 4.0 wt% lithium hexafluorophosphate, 1.0 wt% lithium difluorobis(oxalyl)phosphate and 0.5 wt% lithium bis(trimethylsilyl)amide are added to the solvent, and the mixture is stirred at 30-40 °C for 2 h; Then, 0.5 wt% 4-trifluoromethyl-vinyl sulfate, 0.4 wt% 3,4-fluorovinyl sulfate, 0.5 wt% hexafluoroisopropoxy cyclotriphosphazene, and 0.4 wt% 3-(2,2,2-trifluoroethoxy)propionitrile were added and dissolved in the mixed solvent, and the mixture was stirred at a temperature of 30-50°C for 0.5 h to obtain an electrolyte.

[0024] The lithium battery comprises the following steps: The battery was assembled with lithium iron phosphate as the positive electrode and graphite as the negative electrode in an argon-filled glove box with the moisture content controlled at <0.1 ppm and the oxygen content controlled at <0.1 ppm.

[0025] Example 2 The difference between Example 2 and Example 1 is that the content of the additive is different, and a perfluorinated wide-temperature electrolyte for a lithium battery is obtained. First, fluoroethylene carbonate, fluoroacetonitrile and low-polarity solvent fluorobenzene are mixed in a volume ratio of 3:7:10 to obtain a perfluorinated solvent, and then 0.5 mol / L lithium bis(fluorosulfonyl)imide, 0.5 mol / L lithium bis(trifluoromethanesulfonyl)imide, 4.0 wt% lithium hexafluorophosphate, 1.0 wt% lithium difluorobis(oxalate)phosphate, and 1.5 wt% lithium bis(trimethylsilyl)amide are added to the solvent, and stirred at 30-40°C for 2 h; Then, 0.4 wt% 4-trifluoromethyl-vinyl sulfate, 1.0 wt% 3,4-fluorovinyl sulfate, 0.4 wt% 3-(2,2,2-trifluoroethoxy)butyronitrile, and 1.0 wt% 3-(2,2,2-trifluoroethoxy)propionitrile were added and dissolved in the mixed solvent, and stirred at a temperature of 40-50°C for 1 h to obtain an electrolyte with a lithium salt concentration of 1 mol / L.

[0026] The lithium battery comprises the following steps: The battery was assembled with lithium iron phosphate as the positive electrode and graphite as the negative electrode in an argon-filled glove box with the moisture content controlled at <0.1 ppm and the oxygen content controlled at <0.1 ppm.

[0027] Example 3 The difference between Example 3 and Example 1 is that the content of the additive is different, and a perfluorinated wide-temperature electrolyte for a lithium battery is obtained. First, fluoroethylene carbonate, fluoroacetonitrile and low-polarity solvent fluorobenzene are mixed in a volume ratio of 3:7:10 to obtain a perfluorinated solvent, and then 0.5 mol / L lithium bis(fluorosulfonyl)imide, 0.5 mol / L lithium bis(trifluoromethanesulfonyl)imide, 4.0 wt% lithium hexafluorophosphate, 1.0 wt% lithium difluorobis(oxalate)phosphate, and 0.5 wt% lithium bis(trimethylsilyl)amide are added to the solvent, and stirred at 30-40°C for 2 h; Then, 0.5 wt% 4-trifluoromethyl-vinyl sulfate, 1.0 wt% 3,4-fluorovinyl sulfate, 0.5 wt% 3-(2,2,2-trifluoroethoxy)propionitrile, and 1.0 wt% 3-(2,2,2-trifluoroethoxy)butyronitrile were added and dissolved in the mixed solvent, and the mixture was stirred at a temperature of 30-50 °C for 3 h to obtain an electrolyte.

[0028] The lithium battery comprises the following steps: The battery was assembled with lithium iron phosphate as the positive electrode and graphite as the negative electrode in an argon-filled glove box with the moisture content controlled at <0.1 ppm and the oxygen content controlled at <0.1 ppm.

[0029] Example 4 The difference between Example 4 and Example 1 is that the solvent is different, and a perfluorinated wide-temperature electrolyte for lithium batteries is obtained. First, fluoroethylene carbonate, fluoroacetonitrile and low-polarity solvent trifluorobenzene are mixed in a volume ratio of 3:7:20 to obtain a perfluorinated solvent, and then 0.5 mol / L lithium bis(trifluoromethanesulfonyl)imide, 0.5 mol / L lithium bis(trifluoromethanesulfonyl)imide, 4.0 wt% lithium hexafluorophosphate, 1.0 wt% lithium difluorobis(oxalate)phosphate, and 0.5 wt% lithium bis(trimethylsilyl)amide are added to the solvent, and stirred at 30-40 °C for 2 h. Then, 0.4 wt% 4-trifluoromethyl-vinyl sulfate, 0.5 wt% 3,4-fluorovinyl sulfate, 0.5 wt% 3-(2,2,2-trifluoroethoxy)propionitrile, and 0.5 wt% 3-(2,2,2-trifluoroethoxy)butyronitrile were added and dissolved in the mixed solvent, and the mixture was stirred at a temperature of 30-50 °C for 3 h to obtain an electrolyte.

[0030] The lithium battery comprises the following steps: The battery was assembled with lithium iron phosphate as the positive electrode and graphite as the negative electrode in an argon-filled glove box with the moisture content controlled at <0.1 ppm and the oxygen content controlled at <0.1 ppm.

[0031] Example 5 The difference between Example 5 and Example 1 is that the solvent ratio is different, and a perfluorinated wide-temperature electrolyte for a lithium battery is obtained. First, fluoroethylene carbonate, fluoroacetonitrile and low-polarity solvent fluorobenzene are mixed in a volume ratio of 3:7:30 to obtain a perfluorinated solvent, and then 0.5 mol / L lithium bis(fluorosulfonyl)imide, 0.5 mol / L lithium bis(trifluoromethanesulfonyl)imide, 1.0 wt% lithium difluorobis(oxalyl)phosphate, and 0.5 wt% lithium bis(trimethylsilyl)amide are added to the solvent, and stirred at 30-40 °C for 2 h. Then, 0.4 wt% 4-trifluoromethyl-vinyl sulfate, 0.5 wt% 3,4-fluorovinyl sulfate, 1.0 wt% 3-(2,2,2-trifluoroethoxy)propionitrile, and 0.5 wt% 3-(2,2,2-trifluoroethoxy)butyronitrile were added and dissolved in the mixed solvent, and the mixture was stirred at a temperature of 30-50 °C for 3 h to obtain an electrolyte.

[0032] The lithium battery comprises the following steps: The battery was assembled with lithium iron phosphate as the positive electrode and silicon carbon as the negative electrode in an argon-filled glove box with the moisture content controlled at <0.1 ppm and the oxygen content controlled at <0.1 ppm.

[0033] Example 6 The difference between Example 6 and Example 1 is that the negative electrode active material is different, and a lithium battery perfluorinated wide temperature electrolyte is obtained. First, fluoroethylene carbonate, fluoroacetonitrile and low polarity solvent fluorobenzene are mixed in a volume ratio of 3:7:20 to obtain a perfluorinated solvent, and then 0.5 mol / L lithium bis(fluorosulfonyl)imide, 0.5 mol / L lithium bis(trifluoromethanesulfonyl)imide, 4.0 wt% lithium hexafluorophosphate, 1.0 wt% lithium difluorobis(oxalate)phosphate, and 0.5 wt% lithium bis(trimethylsilyl)amide are added to the solvent, and stirred at 30-40 °C for 2 h. Then, 0.4 wt% of 4-trifluoromethyl-vinyl sulfate, 0.5 wt% of 3,4-fluorovinyl sulfate, 1.0 wt% of 3-(2,2,2-trifluoroethoxy)propionitrile, and 1.0 wt% of 3-(2,2,2-trifluoroethoxy)butyronitrile were added and dissolved in the mixed solvent, and the mixture was stirred at a temperature of 30-50 °C for 3 h to obtain an electrolyte.

[0034] The lithium battery comprises the following steps: The battery was assembled with lithium iron phosphate as the positive electrode and graphite as the negative electrode in an argon-filled glove box with the moisture content controlled at <0.1 ppm and the oxygen content controlled at <0.1 ppm.

[0035] Example 7 The difference between Example 7 and Example 1 is that the content of the additive is different, and a perfluorinated wide-temperature electrolyte for a lithium battery is obtained. First, fluoroethylene carbonate, fluoroacetonitrile and low-polarity solvent fluorobenzene are mixed in a volume ratio of 3:7:20 to obtain a perfluorinated solvent, and then 0.5 mol / L lithium bis(fluorosulfonyl)imide, 0.5 mol / L lithium bis(trifluoromethanesulfonyl)imide, 4.0 wt% lithium hexafluorophosphate, 1.0 wt% lithium difluorobis(oxalate)phosphate, and 0.5 wt% lithium bis(trimethylsilyl)amide are added to the solvent, and stirred at 30-40°C for 2 h. Then, 0.4 wt% 4-trifluoromethyl-vinyl sulfate, 0.5 wt% 3,4-fluorovinyl sulfate, and 0.5 wt% 3-(2,2,2-trifluoroethoxy)butyronitrile were added and dissolved in the mixed solvent, and the mixture was stirred at a temperature of 30-50 °C for 3 h to obtain an electrolyte.

[0036] The lithium battery comprises the following steps: The battery was assembled with lithium iron phosphate as the positive electrode and graphite as the negative electrode in an argon-filled glove box with the moisture content controlled at <0.1 ppm and the oxygen content controlled at <0.1 ppm.

[0037] Comparative Example 1 This comparative example provides a single-solvent electrolyte. First, 0.5 mol / L lithium bis(fluorosulfonyl)imide, 0.5 mol / L lithium bis(trifluoromethanesulfonyl)imide, 4.0 wt% lithium hexafluorophosphate, 1.0 wt% lithium difluorobis(oxalato)phosphate, and 0.5 wt% lithium bis(trimethylsilyl)amide are added to a solvent and stirred at 30-40°C for 2 h to obtain an electrolyte.

[0038] The lithium battery comprises the following steps: The battery was assembled with lithium iron phosphate as the positive electrode and graphite as the negative electrode in an argon-filled glove box with the moisture content controlled at <0.1 ppm and the oxygen content controlled at <0.1 ppm.

[0039] The battery test voltage range provided by this test for Examples 1 to 7 and Comparative Example 1 is 2.5 to 4.3 V.

[0040] This example tests the electrochemical performance of soft-pack batteries including the wide-temperature electrolyte provided in the examples and comparative examples. Specifically, the discharge specific capacity of the button-type battery obtained in the application example was tested at -80°C, -40°C, -20°C, 25°C, 40°C, and 80°C, where each temperature was cycled for five weeks with a charge and discharge rate of 1 C, and the average value was taken. The test results are shown in Table 1.

[0041]

[0042] It can be seen from the examples and comparative examples that the perfluorinated wide-temperature electrolyte proposed in the present invention helps to achieve rapid liquid phase transmission, interfacial charge transfer, and stable battery cycling at a wide temperature. Figure 2 It can also be seen that the wide temperature electrolyte meets the requirements of stable circulation under high pressure. The above is a detailed description of several embodiments and comparative examples of the present invention, but the contents described are only preferred embodiments of this experiment and cannot be considered to limit the scope of implementation of the present invention. All equal changes made according to the scope of application of the present invention shall be included in the scope of the patent coverage of the present invention.

[0043] The above embodiments are only examples for clear explanation, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here, so the obvious changes or modifications derived are still within the protection scope of the invention.

Claims

1. A perfluorinated wide-temperature electrolyte for lithium batteries, characterized in that: The invention comprises lithium salt, additives and solvents, wherein the organic solvent comprises a fluorinated compound, the additives comprise a first additive and a second additive, the first additive is a water-removing additive, and the second additive is a film-forming additive.

2. A perfluorinated wide temperature electrolyte for lithium batteries according to claim 1, characterized in that: The lithium salt is selected from one or more of lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium difluorobis(oxalato)phosphate, lithium difluorooxalatoborate, and lithium bis(trimethylsilyl)amide.

3. A perfluorinated wide temperature electrolyte for lithium battery according to claim 1, characterized in that: The first additive includes a fluorinated additive, mainly selected from one or more of hexafluoroisopropoxy cyclotriphosphazene, 3-(2,2,2-trifluoroethoxy)propionitrile, and 3-(2,2,2-trifluoroethoxy)butyronitrile, and the second additive is selected from one or more of 3,4-fluorovinyl sulfate and 4-trifluoromethyl-vinyl sulfate.

4. A method for synthesizing 3-(2,2,2-trifluoroethoxy)propionitrile and 3-(2,2,2-trifluoroethoxy)butyronitrile under pressure, characterized in that: The following steps are involved: Step 1, uniformly mixing trifluoroethanol, acrylonitrile (crotononitrile) and a catalyst and placing the mixture in an autoclave to maintain a high pressure environment; Step 2, heating the mixture in the autoclave to react the heated trifluoroethanol with acrylonitrile (crotononitrile) to synthesize trifluoroethoxy acrylonitrile (3-(2,2,2-trifluoroethoxy)butyronitrile); Step 3: remove low boiling points by distillation under reduced pressure to obtain 3-(2,2,2-trifluoroethoxy)propionitrile and 3-(2,2,2-trifluoroethoxy)butyronitrile.

5. A perfluorinated wide temperature electrolyte for lithium battery according to claim 1, characterized in that: The organic solvent is selected from one or more of fluoroethylene carbonate, fluoroacetonitrile, fluorobenzene and trifluorobenzene.

6. A perfluorinated wide temperature electrolyte for lithium battery according to claim 1, characterized in that: The weight ratio of the lithium salt, additive and organic solvent is 0.5-15:0.4-5:70-85.

7. A perfluorinated wide temperature electrolyte for lithium battery according to claim 1, characterized in that: The electrolyte preparation comprises the following steps: (1) Add lithium salt to organic solvent and stir at 30-50 °C for 0.5-5 h; (2) Adding additives to the clarified liquid and mixing them evenly obtains the perfluorinated electrolyte for wide-temperature lithium batteries.

8. A perfluorinated wide temperature electrolyte for lithium batteries according to claims 1 to 6, characterized in that: The preparation process of the electrolyte is carried out under an inert atmosphere, and the inert atmosphere environment satisfies H2O<0.1 ppm and O2<0.1 ppm.

9. A lithium ion battery, characterized in that: The invention comprises the perfluorinated wide-temperature electrolyte for lithium batteries as described in any one of claims 1 to 7.

10. The lithium ion battery according to claim 9, characterized in that: The positive electrode material of the lithium-ion battery is lithium iron phosphate, and the negative electrode material is one or more of graphite and silicon carbon.

Images