WO2023236664A1 - Use of fluoroether solvent and electrolyte in energy storage batteries - Google Patents

Abstract

Provided in the present invention are a fluoroether solvent and an electrolyte which are applied to energy storage batteries, particularly lithium metal batteries, the fluoroether solvent having a structure as shown in formula I. In the present invention, at least one fluorine atom is introduced to the two ends of a molecular chain of an ether, so as to ensure that the fluoroether molecule has an excellent salt dissolving capability, and the introduction of the fluorine atom can effectively reduce electron cloud density of ether oxygen so as to improve oxidation stability of the ether molecule, thus achieving excellent cycling stability of a high-voltage lithium metal battery. Meanwhile, a fluorinated end group having local strong polarity can act with a cation of salt to improve ionic conductivity of an electrolyte, thereby improving rapid charging and discharging properties of the high-voltage lithium metal battery.

Description

Application of a fluoroether solvent and electrolyte in energy storage batteries

This application requires the priority of the Chinese patent application submitted to the China Patent Office on June 9, 2022, with the application number 202210645377.7 and the invention title "Application of fluorinated ether solvent and electrolyte in energy storage batteries", The entire contents of which are incorporated herein by reference.

Technical field

The invention belongs to the technical field of energy storage batteries, and in particular relates to a fluoroether solvent and electrolyte used in energy storage lithium metal batteries.

Background technique

Currently, lithium-ion batteries are highly competitive among many energy storage batteries. However, lithium-ion batteries using graphite anodes cannot meet the needs of various high-performance electric equipment due to their limited energy density. In recent years, lithium metal batteries using lithium metal as the negative electrode with high specific capacity (3860mAh g ^-1 ) and low potential (-3.04V compared to standard hydrogen electrodes) have been regarded as the most promising next-generation energy storage batteries. one. However, the highly active lithium metal anode reacts with essentially all available electrolytes, resulting in low Coulombic efficiency, poor cycling performance, and lithium dendrite growth. In addition, lithium metal batteries require high-voltage and high-capacity cathode materials such as nickel-rich NMC811 cathode materials to maximize the energy density of the full battery. However, as the cut-off charging voltage of NMC811 increases, the side reaction between the positive electrode and the electrolyte is very serious and induces faster capacity fading. Therefore, the interfacial instability between the positive and negative electrodes and the electrolyte is of great significance for the development and commercialization of high-energy-density lithium metal batteries.

In order to alleviate the above problems, the development of ether-based electrolytes, especially high-concentration or local high-concentration electrolytes, is considered to be one of the effective ways to achieve cycle stability of high-voltage NMC811 lithium metal batteries. However, even in high-concentration or local high-concentration electrolytes, Some ether free molecules still exist in the concentrated electrolyte, and the decomposition of unstable ether molecules may have a significant impact on the electrochemical performance of high-voltage lithium metal batteries. In addition, the low intrinsic ionic conductivity of high-concentration or local high-concentration electrolytes also affects the rapid charge and discharge performance of lithium metal batteries. Therefore, existing ether-based electrolytes still cannot be practically used in lithium metal batteries.

The same problem also exists in high-voltage lithium-ion batteries, sodium metal (or ion) batteries, potassium metal (or ion) batteries, magnesium metal batteries and zinc metal battery energy storage systems based on organic electrolytes.

Contents of the invention

In view of this, the technical problem to be solved by the present invention is to provide a fluoroether solvent and electrolyte for energy storage batteries, especially lithium metal batteries. The fluoroether solvent provided by the present invention has high dissolved salts. The ability and oxidation stability of ether-based electrolytes have significantly improved the antioxidant capacity and rapid charge and discharge capabilities, further improving the application of ether-based electrolytes in practical lithium metal batteries.

The invention provides a fluoroether solvent, which has a structure shown in Formula I:

In formula I, the values of n ₁ , n ₂ and n ₃ are independently 1 to 3, and X=H or F.

Preferably, the fluoroether solvent is selected from bis(2-fluoroethoxy)ethane.

The invention also provides a preparation method for the above-mentioned fluoroether solvent, which includes the following steps:

Mix chlorinated ether, metal fluoride and alcohol to react to obtain a reaction product;

The reaction product is filtered, extracted and distilled under reduced pressure to obtain a fluoroether solvent.

Preferably, the chlorinated ether is bis(chloromethoxy)methane, bis(2-chloroethoxy)methane, bis(chloromethoxy)ethane, or bis(2-chloroethoxy)ethane. , bis(chloromethoxy)propane, bis(2-chloroethoxy)propane, 1-chloro-2-(methoxymethoxy)ethane, (methoxymethoxy)chloromethane, 2 -Methoxyethoxymethyl chloride, 1-(2-chloroethoxy)-2-methoxyethane, 1-(2-chloroethoxy)-2-ethoxyethane A sort of;

The metal fluoride is one or more of lithium fluoride, sodium fluoride, potassium fluoride, and cesium fluoride;

The alcohol is one or more of ethylene glycol, polyethylene glycol, diethylene glycol, and tetraethylene glycol.

Preferably, the reaction temperature is 80-200°C and the reaction time is 2-16 hours;

The molar ratio of the chlorinated ether and metal fluoride is 1:1 to 1:10;

The molar volume ratio of the metal fluoride to the alcohol is 0.1 mol: 10 to 100 mL.

The invention also provides an electrolyte containing fluorinated ether solvents, including fluorinated ether solvents, and the fluorinated ether solvent has the structure shown in Formula I

In formula I, the values of n ₁ , n ₂ and n ₃ are independently 1 to 3, and X=H or F.

Preferably, the electrolyte solution further includes electrolyte salt and diluent.

Preferably, the electrolyte salt is one or more of lithium salt, sodium salt, potassium salt, magnesium salt, and zinc salt; the lithium salt is selected from Li ₂ SO ₄ , LiClO ₄ , LiNO ₃ , LiF, and LiCF. ₃ SO ₃ , LiPF ₆ , Li(FSO ₂ ) ₂ N, LiBF ₄ , Li(CF ₃ CF ₂ SO ₂ ) ₂ N or Li(CF ₃ SO ₂ ) ₂ N, the sodium salt is selected from NaClO ₄ , NaNO ₃ . NaF, Na(FSO ₂ ) ₂ N, Na(CF ₃ CF ₂ SO ₂ ) ₂ N, NaPF ₆ , Na ₂ SO ₄ or NaCF ₃ SO ₃ , the potassium salt is selected from KNO ₃ , KClO ₄ , KPF ₆ , K(FSO ₂ ) ₂ N, K(CF ₃ SO ₂ ) ₂ N, K ₂ SO ₄ , KF or KCl, the magnesium salt is selected from Mg(CF ₃ SO ₃ ) ₂ , MgCl ₂ or MgSO ₄ ; the The zinc salt is selected from Zn(CF ₃ SO ₃ ) ₂ , ZnSO ₄ or Zn(CH ₃ OO) ₂ .

The diluent is selected from 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2, 2-Trifluoroethyl ether, bis(2,2,2-trifluoroethyl) ether, tris(2,2,2-trifluoroethyl)orthoformate, 1H,1H,5H-octafluoroacrylate One or more of amyl ester-1,1,2,2-tetrafluoroethyl ether, fluorobenzene, and 1,3,5 trifluorobenzene.

Preferably, the molar ratio of the electrolyte salt and the fluorinated ether solvent is 1:0.1-1:10, and the molar ratio of the fluorinated ether solvent and the diluent is 1:0-1:10.

The invention also provides an energy storage battery, including a fluorinated ether solvent, and the fluorinated ether solvent has a structure shown in formula I

In formula I, the values of n ₁ , n ₂ and n ₃ are independently 1 to 3, and X=H or F;

The energy storage battery is selected from the group consisting of lithium metal batteries, high-voltage lithium ion batteries based on organic electrolyte, sodium metal (or ion) batteries, potassium metal (or ion) batteries, magnesium metal batteries and zinc metal battery energy storage systems.

Compared with the prior art, the present invention provides a fluoroether solvent and an electrolyte that are used in energy storage batteries, especially lithium metal batteries. The fluoroether solvent has the structure shown in Formula I. The present invention ensures that fluorinated ether molecules have excellent ability to dissolve salts by introducing at least one fluorine atom at both ends of the ether molecular chain, and the introduction of fluorine atoms can effectively reduce the electron cloud density of ether oxygen and improve the oxidation stability of ether molecules. properties, achieving excellent cycle stability of high-voltage lithium metal batteries; at the same time, the local highly polar fluorinated end groups can interact with the cations of the salt to increase the ionic conductivity of the electrolyte, improving the performance of high-voltage lithium metal batteries. Fast charge and discharge performance.

Description of the drawings

Figure 1 is the NMR characterization spectrum of ¹ H, ¹³ C, and ¹⁹ F of the product synthesized in Example 2;

Figure 2 is a linear scan voltammetric test comparison diagram of the traditional ether local high-concentration electrolyte in Example 1 and the fluoroether local high-concentration electrolyte in Example 2;

Figure 3 shows the traditional ether localized high-concentration electrolyte in Example 1 and the fluorinated ether localized electrolyte in Example 2. Comparison chart of cycle stability and Coulombic efficiency of polycrystalline NMC811 battery using high concentration electrolyte at 4.6V and C/3;

Figure 4 shows the cycle stability and stability of single crystal NMC811 batteries at 4.7V and C/3 using the traditional ether localized high-concentration electrolyte in Example 1 and the fluorinated ether localized high-concentration electrolyte in Example 2. Coulomb efficiency comparison chart;

Figure 5 is the first charge and discharge curve of the traditional ether localized high-concentration electrolyte used in the polycrystalline NMC811 battery in Example 1 at 4.6V and C/3;

Figure 6 is a comparison chart of the ionic conductivity of the traditional ether localized high-concentration electrolyte in Example 1 and the fluorinated ether localized high-concentration electrolyte in Example 2 under different temperature ranges;

Figure 7 is a comparison chart of the charge and discharge curves of the traditional ether localized high-concentration electrolyte in Example 1 and the fluorinated ether localized high-concentration electrolyte in Example 2 for polycrystalline NMC811 batteries at 4.5V and 1C;

Figure 8 is a comparison of the cycle stability and Coulombic efficiency of the traditional ether-based local high-concentration electrolyte in Example 1 and the fluorinated ether-based local high-concentration electrolyte in Example 2 for polycrystalline NMC811 batteries at 4.6V and 1C. picture;

Figure 9 is a diagram of the cycle stability and Coulombic efficiency of the polycrystalline NMC811 battery using the fluoroether localized high-concentration electrolyte in Example 2 at 4.6V and 2C;

Figure 10 is a comparison chart of the rate performance of the polycrystalline NMC811 battery using the fluoroether local high-concentration electrolyte in Example 2 at 4.6V;

Figure 11 is a linear scan voltammetric test comparison chart between the traditional ether dilute concentration electrolyte in Example 10 and the fluoroether dilute concentration electrolyte in Example 11.

Detailed ways

The invention provides a fluoroether solvent, which has a structure shown in Formula I:

In formula I, the values of n ₁ , n ₂ and n ₃ are independently 1 to 3, and X=H or F.

In some embodiments of the present invention, the fluoroether solvent is selected from bis(2-fluoroethoxy)ethane.

The invention also provides a preparation method of the fluoroether solvent, which includes the following steps:

Mix chlorinated ether, metal fluoride and alcohol to react to obtain a reaction product;

The reaction product is filtered, extracted and distilled under reduced pressure to obtain a fluoroether solvent.

Wherein, the chlorinated ether is bis(chloromethoxy)methane, bis(2-chloroethoxy)methane, bis(chloromethoxy)ethane, bis(2-chloroethoxy)ethane , bis(chloromethoxy)propane, bis(2-chloroethoxy)propane, 1-chloro-2-(methoxymethoxy)ethane, (methoxymethoxy)chloromethane, 2 -Methoxyethoxymethyl chloride, 1-(2-chloroethoxy)-2-methoxyethane, 1-(2-chloroethoxy)-2-ethoxyethane One, preferably bis(2-chloroethoxy)ethane.

The metal fluoride is one or more of lithium fluoride, sodium fluoride, potassium fluoride and cesium fluoride, preferably potassium fluoride.

The alcohol is one or more of ethylene glycol, polyethylene glycol, diethylene glycol and tetraethylene glycol, preferably tetraethylene glycol.

The molar ratio of the chlorinated ether and the metal fluoride is 1:1 to 1:10, preferably 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7 , 1:8, 1:9, 1:10, or any value between 1:1 and 1:10;

The molar volume ratio of the metal fluoride to the alcohol is 0.1 mol: 10 to 100 mL, preferably 0.1 mol: 10 mL, 0.1 mol: 25 mL, 0.1 mol: 50 mL, 0.1 mol: 75 mL, 0.1 mol: 100 mL, or 0.1 mol: Any value between 10 and 100mL.

After mixing the chlorinated ether, metal fluoride and alcohol, the reaction is carried out to obtain a reaction product. Wherein, the temperature of the reaction is 80-200°C, preferably 80, 100, 120, 140, 160, 180, 200, or any value between 80-200, and the time is 2-16 hours, preferably 2, 4, 6, 8, 10, 12, 14, 16, or any value between 2 and 16 hours.

After the reaction is completed, the reaction product is obtained. Then, the reaction product is filtered to remove unreacted metal fluoride to obtain a filtered product.

The filtered material is then washed. In the present invention, it is preferred to use anhydrous ether extraction and washing. The number of extractions is preferably 3 times. Then the diethyl ether was evaporated under reduced pressure to obtain crude product.

Finally, the crude product is distilled under reduced pressure to obtain a fluoroether solvent. The temperature of the product collected by vacuum distillation is 30°C to 80°C, preferably 30, 40, 50, 60, 70, 80, or any value between 30°C and 80°C.

The invention also provides an electrolyte containing fluorinated ether solvents, including fluorinated ether solvents, and the fluorinated ether solvent has the structure shown in Formula I

In formula I, the values of n ₁ , n ₂ and n ₃ are independently 1 to 3, and X=H or F.

The specific description of the fluoroether solvent is as described above and will not be described again.

In the present invention, the fluoroether localized high-concentration electrolyte further includes an electrolyte salt and a diluent.

Wherein, the electrolyte salt is one or more of lithium salt, sodium salt, potassium salt, magnesium salt, and zinc salt; the lithium salt is selected from Li ₂ SO ₄ , LiClO ₄ , LiNO ₃ , LiF, and LiCF ₃ SO ₃ , LiPF ₆ , Li(FSO ₂ ) ₂ N, LiBF ₄ , Li(CF ₃ CF ₂ SO ₂ ) ₂ N or Li(CF ₃ SO ₂ ) ₂ N, the sodium salt is selected from NaClO ₄ , NaNO ₃ , NaF, Na(FSO ₂ ) ₂ N, Na(CF ₃ CF ₂ SO ₂ ) ₂ N, NaPF ₆ , Na ₂ SO ₄ or NaCF ₃ SO ₃ , the potassium salt is selected from KNO ₃ , KClO ₄ , KPF ₆ , K(FSO ₂ ) ₂ N, K(CF ₃ SO ₂ ) ₂ N, K ₂ SO ₄ , KF or KCl, the magnesium salt is selected from Mg(CF ₃ SO ₃ ) ₂ , MgCl ₂ or MgSO ₄ ; The zinc salt is selected from Zn(CF ₃ SO ₃ ) ₂ , ZnSO ₄ or Zn(CH ₃ OO) ₂ .

The diluent is selected from 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2, 2-Trifluoroethyl ether, bis(2,2,2-trifluoroethyl) ether, tris(2,2,2-trifluoroethyl)orthoformate, 1H,1H,5H-octafluoroacrylate One or more of amyl ester-1,1,2,2-tetrafluoroethyl ether, fluorobenzene, and 1,3,5 trifluorobenzene.

The molar ratio of the electrolyte salt and the fluoroether solvent is 1:0.1 to 1:10, preferably 1:0.1, 1:0.3, 1:0.5, 1:0.8, 1:1, 1:3, 1: 5, 1:8, 1:10, or any value between 1:0.1 and 1:10.

The molar ratio of the fluoroether solvent and diluent is 1:0 to 1:10, preferably 1:0, 1:0. 1, 1:0.3, 1:0.5, 1:0.8, 1:1, 1:3, 1:5, 1:8, 1:10, or any value between 1:0 and 1:10.

The invention also provides an energy storage battery, including a fluorinated ether solvent, and the fluorinated ether solvent has a structure shown in formula I

In formula I, the values of n ₁ , n ₂ and n ₃ are independently 1 to 3, and X=H or F;

The energy storage battery is selected from the group consisting of lithium metal batteries, high-voltage lithium ion batteries based on organic electrolyte, sodium metal (or ion) batteries, potassium metal (or ion) batteries, magnesium metal batteries and zinc metal battery energy storage systems.

By introducing at least one fluorine atom at both ends of the ether molecular chain, the present invention ensures that the fluorinated ether molecules It has excellent ability to dissolve salts, and the introduction of fluorine atoms can effectively reduce the electron cloud density of ether oxygen to improve the oxidation stability of ether molecules, achieving excellent cycle stability of high-voltage lithium metal batteries; at the same time, the local strong polarity The fluorinated end group can interact with the cations of the salt to increase the ionic conductivity of the electrolyte and improve the rapid charge and discharge performance of high-voltage lithium metal batteries.

The fluoroether solvent and electrolyte of the present invention are used in energy storage batteries, especially lithium metal batteries, which can significantly improve the oxidation stability and ion conductivity of the electrolyte, so that the lithium metal battery has excellent high voltage cycle performance. and fast charge and discharge capabilities. The invention has the potential for large-scale production and has great application prospects in practical lithium metal batteries.

In order to further understand the present invention, the application of the fluoroether solvents and electrolytes provided by the present invention in energy storage batteries will be described below with reference to the examples. The scope of protection of the present invention is not limited by the following examples.

Example 1:

This embodiment provides a traditional ether localized high-concentration electrolyte, which has the following composition: the electrolyte solute is lithium bisfluorosulfonimide, the solvent is a traditional ether solvent (ethylene glycol diethyl ether), and the diluent is 1 ,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether. Weigh lithium bisfluorosulfonyl imide, solvent, and diluent, and prepare a traditional ether local high-concentration electrolyte. The salt:ethylene glycol diethyl ether:diluent in the local high-concentration electrolyte is 1:1. : 3 (salt: glycol diethyl ether: diluent, molar ratio), perform a linear sweep voltammetry test.

Example 2:

The preparation method of a fluoroether solvent is as follows:

Mix 0.08 mol of bis(2-chloroethoxy)ethane, 0.32 mol of potassium fluoride and 80 mL of tetraethylene glycol, and react in an oil bath at 180°C for 8.5 hours to obtain the reacted mixture. Filter the unreacted fluorine potassium, extracted three times with diethyl ether, and rotary evaporated under reduced pressure to remove the diethyl ether to obtain a crude product. The crude product was distilled under reduced pressure and the liquid at 50°C was collected to obtain the final product as bis(2-fluoroethoxy)ethane.

The NMR characterization results of ¹ H, ¹³ C, and ¹⁹ F of the synthesized product are shown in Figure 1. The spectrum shows the successful synthesis of bis(2-fluoroethoxy)ethane.

This embodiment provides a fluoroether localized high-concentration electrolyte, which has the following composition: the electrolyte solute is lithium bisfluorosulfonimide, the solvent is the above-mentioned fluoroether solvent, and the diluent is 1,1,2 ,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether. Weigh lithium bisfluorosulfonimide, solvent, and diluent to prepare fluorinated ethers Local high concentration electrolyte, the salt in the local high concentration electrolyte: bis (2-fluoroethoxy) ethane: diluent is 1:1.65:3 (salt: bis (2-fluoroethoxy) Ethane: diluent, molar ratio), perform a linear sweep voltammetry test.

The test results are shown in Figure 2. Compared with the electrolyte in Example 1, the electrolyte in Example 2 has higher oxidation stability.

Example 3:

The fluorinated ether type local high-concentration electrolyte in Example 2 was selected as the experimental group of this example, and the traditional ether type local high-concentration electrolyte in Example 1 was selected as the control group. Using polycrystalline NCM811 (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ ) as the positive electrode and Li metal (450 micron) as the negative electrode, the charge and discharge cycle test was performed at a voltage of 4.6V and a C/3 rate.

The test results are shown in Figure 3. The fluoroether localized high-concentration electrolyte in Example 2 has excellent cycle stability at 4.6V.

The test results are shown in Figure 4. The traditional ether localized high-concentration electrolyte in Example 1 was obviously overcharged, which was caused by the unstable decomposition of the traditional ether solvent.

Example 4:

The fluorinated ether type local high-concentration electrolyte in Example 2 was selected as the experimental group of this example, and the traditional ether type local high-concentration electrolyte in Example 1 was selected as the control group. Using single crystal NCM811 (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ ) as the positive electrode and Li metal (450 micron) as the negative electrode, the charge and discharge cycle test was performed at a voltage of 4.7V and a C/3 rate.

The test results are shown in Figure 5. The fluoroether local high-concentration electrolyte in Example 2 can still maintain good cycle performance at 4.7V, while the traditional ether local high-concentration electrolyte in Example 1 cannot function normally. When working, the battery capacity decreases significantly.

Example 5:

The fluorinated ether type local high-concentration electrolyte in Example 2 was selected as the experimental group of this example, and the traditional ether type local high-concentration electrolyte in Example 1 was selected as the control group. Test the ionic conductivity of the electrolyte at different temperatures.

The test results are shown in Figure 6. In the wide temperature range of -30°C to 30°C, the fluoroether localized high-concentration electrolyte in Example 2 has higher ionic conductivity, especially in a room temperature environment.

Example 6:

The fluorinated ether type local high-concentration electrolyte in Example 2 was selected as the experimental group of this example, and the traditional ether type local high-concentration electrolyte in Example 1 was selected as the control group. Using polycrystalline NCM811 (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ ) as the positive electrode and Li metal (450 micron) as the negative electrode, the charge and discharge cycle test was performed at a voltage of 4.5V and a rate of 1C to obtain the charge and discharge curve.

The test results are shown in Figure 7. The traditional ether local high-concentration electrolyte in Example 1 did not oxidize during the first charging process like the fluoroether local high-concentration electrolyte in Example 2 at a voltage of 4.5V. break down. During the cycle process, the traditional ether local high-concentration electrolyte in Example 1 has a larger charge-discharge platform voltage difference, which is caused by greater polarization during the charge-discharge cycle.

Example 7:

The fluorinated ether type local high-concentration electrolyte in Example 2 was selected as the experimental group of this example, and the traditional ether type local high-concentration electrolyte in Example 1 was selected as the control group. Using polycrystalline NCM811 (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ ) as the positive electrode and Li metal (450 micron) as the negative electrode, the charge and discharge cycle test was performed at a voltage of 4.6V and a rate of 1C.

The test results are shown in Figure 8. Under rapid charge and discharge and high voltage, the fluoroether local high-concentration electrolyte in Example 2 showed excellent cycle performance, while the traditional ether local high-concentration electrolyte in Example 1 Liquid cannot be circulated for long periods of time.

Example 8:

The fluorinated ether localized high-concentration electrolyte in Example 2 was selected as the research object of this example. Using polycrystalline NCM811 (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ ) as the positive electrode and Li metal (450 micron) as the negative electrode, the charge and discharge cycle test was performed at a voltage of 4.6V and a rate of 2C.

The test results are shown in 9. The fluoroether localized high-concentration electrolyte in Example 2 has excellent high voltage and high-rate charge and discharge cycle stability.

Example 9:

The fluorinated ether type local high-concentration electrolyte in Example 2 was selected as the experimental group of this example, and the traditional ether type local high-concentration electrolyte in Example 1 was selected as the control group. Using polycrystalline NCM811 (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ ) as the positive electrode and Li metal (450 micron) as the negative electrode, the charge and discharge rate test was performed at a voltage of 4.6V.

As shown in the test result 10, the fluoroether local high-concentration electrolyte in Example 2 can release a higher capacity than the traditional ether local high-concentration electrolyte in Example 1 at different magnification rates.

Example 10:

This embodiment provides a traditional ether localized high-concentration electrolyte, the composition of which is as follows: the electrolyte solvent is a traditional ether solvent (ethylene glycol diethyl ether), and the solute is lithium bisfluorosulfonyl imide; weigh the bisfluoride Dissolve lithium sulfonyl imide in a solvent and prepare a traditional ether dilute electrolyte. The concentration of the electrolyte is 1 mole of lithium bisfluorosulfonyl imide per liter of ethylene glycol diethyl ether. Perform a linear scan. Voltammetry test.

Example 11:

This embodiment provides a fluoroether dilute concentration electrolyte, the composition of which is as follows: the electrolyte solvent is the fluoroether solvent in Example 2, and the solute is lithium bisfluorosulfonimide; weigh the bisfluorosulfonyl Dissolve lithium imide in a solvent and prepare a fluoroether dilute concentration electrolyte. The concentration of the electrolyte is that every liter of fluoroether solvent contains 1 mole of lithium bisfluorosulfonyl imide. Linear scanning volts are performed. An test test.

The test results are shown in Figure 11. Compared with the electrolyte in Example 10, the electrolyte in Example 11 has higher oxidation stability.

The above are only the preferred embodiments of the present invention. It should be pointed out that those of ordinary skill in the art can also make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications can also be made. should be regarded as the protection scope of the present invention.

Claims (10)

1. A fluoroether solvent, characterized in that the fluoroether solvent has a structure shown in formula I:
   

   In formula I, the values of n ₁ , n ₂ and n ₃ are independently 1 to 3, and X=H or F.
2. The fluoroether solvent according to claim 1, characterized in that the fluoroether solvent is selected from bis(2-fluoroethoxy)ethane.
3. A method for preparing a fluoroether solvent as claimed in claim 1 or 2, characterized in that it includes the following steps:

   Mix chlorinated ether, metal fluoride and alcohol to react to obtain a reaction product;

   The reaction product is filtered, extracted and distilled under reduced pressure to obtain a fluoroether solvent.
4. The preparation method according to claim 3, characterized in that the chlorinated ether is bis(chloromethoxy)methane, bis(2-chloroethoxy)methane, bis(chloromethoxy)ethane, Bis(2-chloroethoxy)ethane, bis(chloromethoxy)propane, bis(2-chloroethoxy)propane, 1-chloro-2-(methoxymethoxy)ethane, ( Methoxymethoxy)methane chloride, 2-methoxyethoxymethyl chloride, 1-(2-chloroethoxy)-2-methoxyethane, 1-(2-chloroethoxy )-2-ethoxyethane;

   The metal fluoride is one or more of lithium fluoride, sodium fluoride, potassium fluoride, and cesium fluoride;

   The alcohol is one or more of ethylene glycol, polyethylene glycol, diethylene glycol, and tetraethylene glycol.
5. The preparation method according to claim 3, characterized in that the reaction temperature is 80-200°C and the reaction time is 2-16 hours;

   The molar ratio of the chlorinated ether and metal fluoride is 1:1 to 1:10;

   The molar volume ratio of the metal fluoride to the alcohol is 0.1 mol: 10 to 100 mL.
6. An electrolyte containing fluorinated ether solvents, characterized in that it includes a fluorinated ether solvent, and the fluorinated ether solvent has a structure shown in Formula I
   

   In formula I, the values of n ₁ , n ₂ and n ₃ are independently 1 to 3, and X=H or F.
7. The electrolyte solution according to claim 6, further comprising an electrolyte salt and a diluent.
8. The electrolyte solution according to claim 6, characterized in that the electrolyte salt is one or more of lithium salt, sodium salt, potassium salt, magnesium salt and zinc salt; the lithium salt is selected from Li ₂ SO _4. LiClO ₄ , LiNO ₃ , LiF, LiCF ₃ SO ₃ , LiPF ₆ , Li(FSO ₂ ) ₂ N, LiBF ₄ , Li(CF ₃ CF ₂ SO ₂ ) ₂ N or Li(CF ₃ SO ₂ ) ₂ N , the sodium salt is selected from NaClO ₄ , NaNO ₃ , NaF, Na(FSO ₂ ) ₂ N, Na(CF ₃ CF ₂ SO ₂ ) ₂ N, NaPF ₆ , Na ₂ SO ₄ or NaCF ₃ SO ₃ , The potassium salt is selected from KNO ₃ , KClO ₄ , KPF ₆ , K(FSO ₂ ) ₂ N, K(CF ₃ SO ₂ ) ₂ N, K ₂ SO ₄ , KF or KCl, and the magnesium salt is selected from Mg(CF ₃ SO ₃ ) ₂ , MgCl ₂ or MgSO ₄ ; the zinc salt is selected from Zn(CF ₃ SO ₃ ) ₂ , ZnSO ₄ or Zn(CH ₃ OO) ₂ ;

   The diluent is selected from 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2, 2-Trifluoroethyl ether, bis(2,2,2-trifluoroethyl) ether, tris(2,2,2-trifluoroethyl)orthoformate, 1H,1H,5H-octafluoroacrylate One or more of amyl ester-1,1,2,2-tetrafluoroethyl ether, fluorobenzene, and 1,3,5 trifluorobenzene.
9. The electrolyte solution according to claim 6, characterized in that the molar ratio of the electrolyte salt and the fluoroether solvent is 1:0.1~1:10, and the molar ratio of the fluoroether solvent and the diluent is 1: 0~1:10.
10. An energy storage battery, characterized in that it includes a fluorinated ether solvent, and the fluorinated ether solvent has a structure shown in Formula I
    

    In formula I, the values of n ₁ , n ₂ and n ₃ are independently 1 to 3, and X=H or F;

    The energy storage battery is selected from the group consisting of lithium metal batteries, high-voltage lithium ion batteries based on organic electrolyte, sodium metal (or ion) batteries, potassium metal (or ion) batteries, magnesium metal batteries and zinc metal battery energy storage systems.