Star-shaped ether compound, electrolyte and lithium battery

Abstract

The present application provides a star-shaped ether compound, an electrolyte and a lithium battery. The star-shaped ether compound has the following structural formula: The star-shaped ether compound is used in the electrolyte to effectively regulate the solvation structure and degree of the electrolyte. When the electrolyte is used in a lithium battery, lithium ions can be uniformly deposited and a uniform and dense SEI film can be formed on the surface of the negative electrode. At the same time, it can have high stability, wettability and high safety for the positive electrode. The lithium battery using the electrolyte has the advantages of long cycle life and high safety.

Description

Technical Field

[0001] The present application relates to the technical field of lithium batteries, and in particular to star-shaped ether compounds, electrolytes and lithium batteries. Background Art

[0002] Lithium metal has a low density (0.59 g / cm 3 ), high theoretical specific capacity (3860mAh / g) and low reduction potential (-3.04Vvs.H + / H2) and is considered to be an ideal negative electrode material for the next generation of lithium batteries. However, there are still some problems in its use: on the one hand, lithium ions are continuously deposited on the surface of lithium metal during the charge and discharge cycle. The local lithium ion concentration gradient leads to different liquid phase mass transfer flow rates, which in turn produces lithium dendrites and eventually causes problems such as short circuits. On the other hand, due to the uneven deposition of lithium ions on the surface of lithium metal, the protruding lithium dendrites on the surface of the negative electrode will continue to grow during the charge and discharge cycle, resulting in the generation of "dead lithium" and reducing the capacity of the negative electrode.

[0003] Therefore, current lithium battery related technologies still need to be improved.

[0004] Application Contents

[0005] The present application aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the purpose of the present application is to provide a star-shaped ether compound, an electrolyte and a lithium battery.

[0006] In one aspect of the present application, the present application provides a star-shaped ether compound. According to an embodiment of the present application, the star-shaped ether compound has the following structural formula:

[0007]

[0008] Wherein, X1, X2, and X3 are each independently a chemical bond or -(CH2) a -;

[0009] R4 is H or -(CH2) b -O-R5;

[0010] R1, R2, R3 and R5 are each independently selected from substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted phenyl, substituted or unsubstituted halophenyl, substituted or unsubstituted benzyl and substituted or unsubstituted halobenzyl;

[0011] The substituents in the above-mentioned substituted alkyl, substituted haloalkyl, substituted phenyl, substituted halophenyl, substituted benzyl and substituted halobenzyl are each independently selected from alkyl, haloalkyl, alkoxy, haloalkoxy, alkoxy substituted alkoxy, alkoxy substituted haloalkoxy, haloalkoxy substituted alkoxy, haloalkoxy substituted haloalkoxy, acyl, cyanoalkoxy and cyano;

[0012] Wherein, at least one of R1, R2, R3 and R5 contains halogen, and the halogen includes at least one of fluorine, chlorine, bromine and iodine, a is an integer of 0 to 10, and b is an integer of 0 to 10.

[0013] The star-shaped ether compound is easy to prepare, easy to store, non-flammable, and has the potential for industrialization. When used in an electrolyte, the star-shaped molecular structure can reduce the intermolecular forces, optimize the solvation structure and degree in the electrolyte, further reduce its viscosity, and increase the wettability of the electrolyte to the electrode sheet. When the electrolyte is used in a lithium battery, lithium ions can be quickly moved to the negative electrode, and lithium ions are uniformly released and deposited on the surface of the negative electrode, thereby improving the safety problems caused by the growth of lithium dendrites. At the same time, it helps to form a tight complex cluster between the lithium ions and the solvent in the electrolyte, which will be evenly distributed on the surface of the negative electrode under the action of the electric field during charging, thereby helping to form a uniform and dense SEI film on the surface of the negative electrode, and can also have high stability, wettability and high safety to the positive electrode. The lithium battery using the electrolyte has the advantages of long cycle life and high safety.

[0014] In another aspect of the present application, the present application provides an electrolyte. According to an embodiment of the present application, the electrolyte includes: a lithium salt; an organic solvent; and the star-shaped ether compound described above. In the electrolyte, by adding a star-shaped ether compound, the intermolecular forces can be reduced, the solvation structure can be optimized, the viscosity of the electrolyte can be reduced, and the wettability of the electrolyte to the electrode sheet can be increased; when used in a lithium battery, the lithium ions can be quickly moved to the negative electrode, and the lithium ions can be uniformly released and deposited on the surface of the negative electrode, thereby improving the safety problems caused by the growth of lithium dendrites; and the lithium ions in the electrolyte can form a compact complex cluster with the solvent, which will be evenly distributed on the surface of the negative electrode under the action of the electric field during charging, thereby helping to form a uniform and dense SEI film on the surface of the negative electrode, and can also have high stability, wettability and high safety to the positive electrode. The lithium battery using this electrolyte has the advantages of long cycle life and high safety.

[0015] In another aspect of the present application, the present application provides a lithium battery. According to an embodiment of the present application, the lithium battery includes: a positive electrode; a negative electrode; a diaphragm, the diaphragm is located between the positive electrode and the negative electrode; the aforementioned electrolyte, the positive electrode, the negative electrode and at least a portion of the diaphragm are immersed in the electrolyte. The lithium battery has a long cycle life and high safety, and because star-shaped ether compounds are added to the electrolyte used, there are fewer restrictions on the positive electrode material. In addition to low-potential lithium iron phosphate, positive electrode materials with higher potential (such as lithium cobalt oxide, ternary positive electrode materials, etc.) can also be used, and the scope of application is wider. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a graph showing the cycle performance test results of the battery of Example 23.

[0017] Figure 2 This is a graph showing the cycle performance test results of the battery of Example 30.

[0018] Figure 3 This is a graph showing the cycle performance test results of the battery of Example 36.

[0019] Figure 4 This is a graph showing the cycle performance test results of the battery of Example 40.

[0020] Figure 5 This is a graph showing the cycle performance test results of the battery of Example 43.

[0021] Figure 6 This is a graph showing the cycle performance test results of the battery in Comparative Example 1.

[0022] Figure 7 This is a graph showing the coulombic efficiency test results of the battery of Example 28.

[0023] Figure 8 This is a graph showing the coulombic efficiency test results of the battery of Example 36.

[0024] Fig. 9 This is a graph showing the coulombic efficiency test results of the battery of Example 37. DETAILED DESCRIPTION

[0025] The embodiments of the present application are described in detail below. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If no specific technology or conditions are indicated in the embodiments, the technology or conditions described in the document in this area or the product specification are used. The reagents used or the instruments that do not indicate the manufacturer are all conventional products that can be obtained commercially.

[0026] In one aspect of the present application, the present application provides a star-shaped ether compound. According to an embodiment of the present application, the star-shaped ether compound has the following structural formula:

[0027]

[0028] Wherein, X1, X2, and X3 are each independently a chemical bond or -(CH2) a -;

[0029] R4 is H and -(CH2) b -O-R5;

[0030] R1, R2, R3 and R5 are each independently selected from substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted phenyl, substituted or unsubstituted halophenyl, substituted or unsubstituted benzyl and substituted or unsubstituted halobenzyl;

[0031] The substituents in the above-mentioned substituted alkyl, substituted haloalkyl, substituted phenyl, substituted halophenyl, substituted benzyl and substituted halobenzyl are each independently selected from alkyl, haloalkyl, alkoxy, haloalkoxy, alkoxy substituted alkoxy, alkoxy substituted haloalkoxy, haloalkoxy substituted alkoxy, haloalkoxy substituted haloalkoxy, acyl, cyanoalkoxy and cyano;

[0032] Wherein, at least one of R1, R2, R3 and R5 contains halogen, and the halogen includes at least one of fluorine, chlorine, bromine and iodine, a is an integer of 0 to 10, and b is an integer of 0 to 10.

[0033] The star-shaped ether compound is easy to prepare, easy to store, non-flammable, and has the potential for industrialization. When used in an electrolyte, the star-shaped molecular structure can reduce the intermolecular forces, optimize the solvation structure and degree in the electrolyte, further reduce its viscosity, and increase the wettability of the electrolyte to the electrode sheet. When the electrolyte is used in a lithium battery, lithium ions can be quickly moved to the negative electrode, and lithium ions are uniformly released and deposited on the surface of the negative electrode, thereby improving the safety problems caused by the growth of lithium dendrites. At the same time, it helps to form a tight complex cluster between the lithium ions and the solvent in the electrolyte, which will be evenly distributed on the surface of the negative electrode under the action of the electric field during charging, thereby helping to form a uniform and dense SEI film on the surface of the negative electrode, and can also have high stability, wettability and high safety to the positive electrode. The lithium battery using the electrolyte has the advantages of long cycle life and high safety.

[0034] It should be noted that the specific meanings of some descriptions and terms used in this article are as follows:

[0035] When a=0, it means that X1, X2 or X3 is a chemical bond, O and C are directly connected. For example, when a=0, The actual structure is

[0036] When b=0, -(CH2) b The actual structure of -O-R5 is -O-R5.

[0037] Each substituent and group It represents the molecular chain connected to the corresponding position in each substituent and group, and the "-" in each substituent and group represents the position connected to other groups.

[0038] "Substituted or unsubstituted alkyl" refers to an unsubstituted alkyl group (-C n H 2n+1 , n is a positive integer) or an alkyl group in which at least one H is substituted by a substituent R (-C n H m R p , p is a positive integer, m is a natural number, and m+p=2n+1).

[0039] Substituted or unsubstituted phenyl refers to unsubstituted phenyl ( -C6H5) or a phenyl group in which at least one H is substituted by a substituent R (-C6H c R d , d is a positive integer, c is a natural number, and c+d=5). It should be noted here that -C6H c R d The six carbon atoms shown in do not include the carbon atoms in the substituent R.

[0040] Substituted or unsubstituted benzyl refers to unsubstituted benzyl ( -C7H7) or a benzyl group in which at least one H is replaced by a substituent R (-C7H e R f , is a positive integer, e is a natural number, and e+f=7). It should be noted here that -C7H e R f The 7 carbon atoms shown in do not include the carbon atoms in the substituent R.

[0041] "Haloalkyl" refers to an alkyl group (-C n H m Y q , Y is a halogen, q is a positive integer, m+q=2n+1), "substituted or unsubstituted haloalkyl" refers to a haloalkyl (i.e., an unsubstituted haloalkyl), or a haloalkyl (-C n H m R p Y q , m+p+q=2n+1) (i.e. substituted haloalkyl).

[0042] "Halophenyl" refers to a phenyl group in which at least one H is substituted with a halogen (-C6H c Y g , g is a positive integer, and c+g=5), "substituted or unsubstituted halophenyl" refers to a halophenyl (i.e., an unsubstituted halophenyl), or a halophenyl in which at least one H is substituted by a substituent R (-C6H c R d Y g , c+d+g=5) (i.e. substituted halogenated phenyl). It should be noted that -C6H c R d Y g The six carbon atoms shown in do not include the carbon atoms in the substituent R.

[0043] "Halobenzyl" refers to a benzyl group (-C7H) in which at least one H is replaced by a halogen. e Y h , h is a positive integer, and e+h=7), “substituted or unsubstituted halobenzyl” refers to a halobenzyl (i.e., an unsubstituted halobenzyl), or a halobenzyl (-C7H) in which at least one H is replaced by a substituent R e R f Y h , e+f+h=7) (i.e. substituted halogenated benzyl). It should be noted that -C7H e R f Y h The 7 carbon atoms shown in do not include the carbon atoms in the substituent R.

[0044] "Alkoxy" refers to -OC i H 2i+1 , i is a positive integer.

[0045] "Haloalkoxy" refers to an alkoxy group in which at least one H is replaced by a halogen (-OC i H j Y k , k is a positive integer, j+k=2i+1).

[0046] "Alkoxy substituted alkoxy" refers to an alkoxy group in which at least one H is substituted with an alkoxy group (-OC i H j Z r , Z is -OC i H 2i+1 , r is a positive integer, j+r=2i+1)

[0047] "Cyano" refers to -CN.

[0048] "Cyanoalkoxy" refers to an alkoxy group in which at least one H is replaced by a cyano group (-OC i H j Wl , W is -CN, l is a positive integer, j+l=2i+1).

[0049] "Acyl" means Ra is H or an alkyl group.

[0050] “R1, R2, R3 and R5 are independently ..." means that the types of groups of R1, R2, R3 and R5 do not affect each other and can be the same or different, as long as they are within the range of groups defined in this application.

[0051] The substituents R mentioned above are each independently alkyl, haloalkyl, alkoxy, haloalkoxy, alkoxy-substituted alkoxy, alkoxy-substituted haloalkoxy, haloalkoxy-substituted alkoxy, haloalkoxy-substituted haloalkoxy, acyl, cyanoalkoxy and cyano.

[0052] According to the embodiments of the present application, R1, R2, R3 and R5 are each independently selected from substituted or unsubstituted C 1-6 Alkyl, substituted or unsubstituted C 1-6 haloalkyl, substituted or unsubstituted phenyl, substituted or unsubstituted halophenyl, substituted or unsubstituted benzyl and substituted or unsubstituted halobenzyl; the above substituted C 1-6 Alkyl, substituted C 1-6 The substituents in the haloalkyl, substituted phenyl, substituted halophenyl, substituted benzyl and substituted halobenzyl are each independently selected from C 1-6 Alkyl, C 1-6 Haloalkyl, C 1-6 Alkoxy, C 1-6 Halogenated alkoxy, C 1-6 Alkoxy substituted C 1-6 Alkoxy, C 1-6 Alkoxy substituted C 1-6 Halogenated alkoxy, C 1-6 Haloalkoxy substituted C 1-6 Alkoxy, C 1-6 Haloalkoxy substituted C 1-6 Halogenated alkoxy, C 1-6 Acyl, C 1-6 In the cyanoalkoxy group and the cyano group, a is an integer of 0-6, and b is an integer of 0-6.

[0053] According to the embodiments of the present application, R1, R2, R3 and R5 are each independently selected from C 1-6 Fluorinated alkyl, C 1-4 Alkoxy substituted C 1-4 Alkyl, C 1-4 Fluoroalkoxy substituted C 1-4 Alkyl, C 1-4 Fluoroalkoxy substituted C1-4 Fluorinated alkyl, C 1-4 Cyanoalkoxy substituted C 1-4 Alkyl, C 1-4 Cyanoalkoxy substituted C 1-4 Fluorinated alkyl, fluorophenyl, C 1-4 Fluorinated alkyl substituted phenyl, C 1-4 Benzyl substituted with fluoroalkyl, C 1-4 Alkyl and first substituent substituted C 1-4 Fluorinated alkyl; wherein the first substituent is C 1-4 Fluoroalkoxy substituted C 1-4 Alkoxy, C 1-4 Fluoroalkoxy substituted C 1-4 Fluoroalkoxy, C 1-4 Alkoxy substituted C 1-4 Fluoroalkoxy and C 1-4 Alkoxy substituted C 1-4 In the alkoxy group, a is an integer of 0-2, and b is an integer of 0-2.

[0054] It should be noted that the above “C 1-4 ” and “C 1-6 " refers to the number of carbon atoms in a group, such as C 1-4 Alkyl refers to an alkyl group having 1 to 4 carbon atoms, specifically methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl. 1-6 Alkyl refers to an alkyl group having 1 to 6 carbon atoms. Other similar descriptions have the same meaning and will not be elaborated here.

[0055] According to an embodiment of the present application, the halogen may be fluorine. Thus, the star-shaped ether compound can improve the stability of the positive electrode material at the positive terminal, and can form a stable, dense, mechanically strong, and surface energy-rich SEI layer of lithium fluoride at the negative terminal. Compared with the fluorinated ethers in the related art, the fluorine substitution in the star-shaped ether compound has the characteristics of higher modifiability and higher degree of fluorination, which can further reduce the proportion of CH bonds in the star-shaped ether compound molecules, thereby improving the safety of the electrolyte. At the same time, the star-shaped ether compound can also be fluorinated to different degrees according to different solvent strategies, so that it has better electrochemical performance and is easier to form a CEI layer and SEI layer rich in LiF.

[0056] According to some specific embodiments of the present application, R1, R2, R3 and R5 are each independently selected from the following groups:

[0057]

[0058] According to the embodiments of the present application, the degree of halogen substitution of the star-shaped ether compound can be flexibly adjusted according to the use needs. Specifically, part of the H in the star-shaped ether compound can be replaced by halogen, or all of the H in the star-shaped compound can be replaced by halogen. In some specific embodiments, R1, R2 and R3 all contain the halogen or R1, R2, R3 and R5 all contain the halogen. The chemical structures of the multiple chains in the star-shaped ether compound can be the same or different. In some specific embodiments, R1, R2 and R3 are the same group or R1, R2, R3 and R5 are the same group. Specifically, the halogen content in the star-shaped compound is increased within a certain range, which can be more conducive to the formation of the SEI film, thereby further improving the performance of the lithium battery; and R1, R2 and R3 are the same group or R1, R2, R3 and R5 are the same group, so that the star-shaped compound has a symmetrical structure, which is more convenient to prepare while having a better use effect.

[0059] According to some embodiments of the present application, X1, X2, and X3 are each independently -(CH2) a -, and R4 is H, wherein a is 0, 1 or 2. According to other embodiments of the present application, X1, X2, and X3 are each independently -(CH2) a -, and R4 is -(CH2) b -O-R5, wherein a is 1 or 2, and b is 0, 1 or 2. Thus, the star-shaped ether compound has a better use effect and is easier to prepare.

[0060] According to some specific examples of the present application, the star-shaped ether compound includes at least one of the following:

[0061]

[0062]

[0063] In another aspect of the present application, the present application provides a method for preparing the aforementioned star-shaped ether compound. According to an embodiment of the present application, the method comprises: reacting substance A with substance B to obtain a star-shaped ether compound Wherein, substance A is selected from Substance B is selected from at least one of R1-Y1, R2-Y2, R3-Y3 and R5-Y5, wherein Z1, Z2, Z3 and Z4 are -OH and Y1, Y2, Y3 and Y5 are each independently selected from halogen and -OTs (p-toluenesulfonyloxy) or Z1, Z2, Z3 and Z4 are halogen and Y1, Y2, Y3 and Y5 are each independently selected from -ONa or -OTs (p-toluenesulfonyloxy); X1, X2, X3, R1, R2, R3, R4 and R5 and b are consistent with the above definitions and are not repeated here.

[0064] According to some embodiments of the present application, the method can be carried out by at least one of the following synthetic routes:

[0065]

[0066]

[0067] Specifically, when R4 is H, React with R1-Y1, R2-Y2 and R3-Y3 to obtain the product When R4 is -(CH2) b -O-R5, you can React with R1-Y1, R2-Y2, R3--Y3 and R5-Y5 to obtain the product

[0068] In some specific embodiments, R1, R2, R3 and R5 are different groups. In this case, the above reaction can be carried out step by step. For example, R1-Y1, R2-Y2, R3-Y3 and R5-Y5 can be separated into The specific reaction order is not particularly limited and can be adjusted according to actual conditions, and Y1, Y2, Y3 and Y5 can be the same or different. In other specific embodiments, R1, R2, R3 and R5 are the same group. In this case, the above reaction can be carried out in one step or in steps as needed. In some specific examples, Y1, Y2, Y3 and Y5 are also the same group. Thus, Reaction with a substance (such as R1-Y1) can give In some other specific embodiments, R1, R2, R3 and R5 are partially the same group and partially different groups. For example, R1, R2, R3 are the same group and R5 is different from R1, R2, R3. R1-Y1, R2-Y2, R3-Y3 can be A one-step reaction is carried out first, and then the intermediate product is reacted with R5-Y5, wherein Y1, Y2, and Y3 are the same group, and Y5 can be the same as or different from Y1, Y2, and Y3.

[0069] Among them, the reaction between -OH and halogen and -OTs (p-toluenesulfonyloxy) and the reaction between halogen and -ONa or -OTs (p-toluenesulfonyloxy) are classic acid-base reactions. The specific reaction conditions can be selected according to actual conditions, for example, they can be carried out according to conventional techniques, which will not be described in detail here.

[0070] In another aspect of the present application, the present application provides an electrolyte. According to an embodiment of the present application, the electrolyte includes: a lithium salt; an organic solvent; and the star-shaped ether compound described above. In the electrolyte, by adding a star-shaped ether compound, the intermolecular forces can be reduced, the solvation structure can be optimized, the viscosity of the electrolyte can be reduced, and the wettability of the electrolyte to the electrode sheet can be increased; when used in a lithium battery, the lithium ions can be quickly moved to the negative electrode, and the lithium ions can be uniformly released and deposited on the surface of the negative electrode, thereby improving the safety problems caused by the growth of lithium dendrites; and the lithium ions in the electrolyte can form a compact complex cluster with the solvent, which will be evenly distributed on the surface of the negative electrode under the action of the electric field during charging, thereby helping to form a uniform and dense SEI film on the surface of the negative electrode, and can also have high stability, wettability and high safety to the positive electrode. The lithium battery using this electrolyte has the advantages of long cycle life and high safety.

[0071] According to an embodiment of the present application, the lithium salt may be selected from at least one of lithium phosphate, lithium borate, lithium boron cluster compound, lithium imide, lithium aluminate, lithium heterocyclic anion salt, lithium halide, lithium sulfonate and derivatives thereof. In some specific embodiments, the lithium salt is selected from at least one of lithium trifluoromethylsulfonate (LiTFA), lithium bistrifluoromethylsulfonyl imide (LiTFSI), lithium bisfluorosulfonyl imide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium hexafluoroarsenide (LiAsF6), lithium difluorophosphate (LiPOF2), lithium tetrafluoroborate (LiBF4), lithium difluorooxalate borate (LiODFB), lithium dioxalate borate (LiBOB), and lithium perchlorate (LiClO4).

[0072] According to an embodiment of the present application, the organic solvent includes an ether compound or an ester compound. Specifically, in some embodiments, the organic solvent in the electrolyte is an ether compound. In other specific embodiments, the organic solvent in the electrolyte is an ester compound. The above electrolytes are all suitable for lithium or lithium-based alloy negative electrode batteries.

[0073] According to an embodiment of the present application, the ether compound includes at least one of a cyclic ether, a linear ether and a fluorinated ether. Specifically, the ether compound can be composed of a cyclic ether, a linear ether, a fluorinated ether, a linear ether and a cyclic ether, a linear ether and a fluorinated ether, a cyclic ether and a fluorinated ether, or a cyclic ether, a linear ether and a fluorinated ether.

[0074] In some embodiments, the cyclic ether includes at least one of 1,3-dioxolane, 1,4-dioxane, tetrahydrofuran, tetrahydropyran and propylene oxide.

[0075] In some embodiments, the linear ether includes at least one of methyl glycol dimethyl ether, methyl glycol diethyl ether, ethylene glycol dimethyl ether (DME), ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, tert-butyl methyl ether, tert-butyl ethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether and dipropylene glycol dimethyl ether.

[0076] In some embodiments, the fluorinated ether includes bis-2,2-trifluoroethyl ether (BTFE), 1,1,1,2,3,3-hexafluoropropyl-2,2,2-trifluoroethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, nonafluorobutyl methyl ether, nonafluorobutyl ethyl ether, nonafluorobutyl propyl ether, 1,1,1,2,2,3,3,4,4-nonafluoroisobutyl methyl ether, n-butyl-1,1,2,2-tetrafluoroethyl ether, 2,2,3,3,3-pentafluoropropyl methyl ether, 2,2,3,3,3-pentafluoro At least one of propyl methyl ether, 1,1,2,3,3,3-hexafluoropropyl ethyl ether, 1,1,2,2-tetrafluoroethyl ether, 1,1,2,2-tetrafluoroethyl methyl ether, 1,1,1,1',1',1',2-hexafluoroisobutyl difluoromethyl ether, 2,2,3,3-tetrafluoropropyl difluoromethyl ether, hexafluoroisopropyl methyl ether, 1,1,2,3,3,3-hexafluoropropyl difluoromethyl ether, tris(2,2,2-trifluoroethyl)orthoformate, 1,1,2,2-tetrafluoroethyl-1H,1H,5H-octafluoropentyl ether, 1,1,2,2-tetrafluoroethyl ethyl ether and trifluoroethyl dodecafluorohexyl ether.

[0077] According to the embodiments of the present application, when the organic solvent includes both linear ether and cyclic ether, the ratio of the two can be flexibly adjusted according to applicable needs. In some specific embodiments, the volume ratio of the linear ether to the cyclic ether can be 1-5:5-9, such as 1:9, 2:9, 3:9, 4:9, 5:9, 6:9, 7:9, 8:9, 9:9, etc. In some specific embodiments, the volume ratio of the linear ether to the cyclic ether can be 1-2:2-3, such as 1:3, 2:3, 3:3, etc.

[0078] According to an embodiment of the present application, the ester compound includes at least one of a linear carbonate, a cyclic carbonate and a phosphate.

[0079] In some embodiments, the cyclic carbonate includes at least one of ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate and halides thereof.

[0080] In some embodiments, the linear carbonate is selected from at least one of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate and methyl propyl carbonate.

[0081] In some embodiments, the phosphate ester is selected from at least one of trimethylphosphine oxide, triethylphosphine oxide, tripropylphosphine oxide, triphenylphosphine oxide, diethyl methylphosphonate, dimethyl methylphosphonate, diphenyl methylphosphonate, bis(2,2,2-trifluoroethyl)methylphosphonate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate and ethylmethylphenyl phosphate.

[0082] According to an embodiment of the present application, the organic solvent may further include at least one of an organic acid ester and a nitrile compound. Specifically, the organic acid ester includes at least one of methyl acetate, ethyl acetate, propyl acetate, ethyl propionate, propyl propionate, methyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-valerolactone and ε-caprolactone; the nitrile compound includes at least one of acetonitrile, propionitrile, butyronitrile, valeronitrile, capronitrile, heptonitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, benzyl cyanide, 2-fluorobenzonitrile and 4-fluorobenzonitrile.

[0083] According to the embodiments of the present application, the molar ratio of the lithium salt, the organic solvent and the star-shaped ether compound is 1-1.5:1-12:0.01-3.5, specifically 1:1:0.01, 1.2:1:0.01, 1.5:1:0.01, 1:2:0.2, 1.2:2:1, 1.2:2:2, 1.2:2:3, 1.2:2:3.5, 1.2:5:0.04, 1.2:10:0.04, 1.2:10:3, etc. Specifically, the specific amount of the star-shaped ether compound can be flexibly adjusted according to the actual situation. Within the above range, it can be applied to various different situations and batteries, is widely applicable, and has a better use effect.

[0084] In another aspect of the present application, the present application provides a lithium battery. According to an embodiment of the present application, the lithium battery includes: a positive electrode; a negative electrode; a diaphragm, the diaphragm is located between the positive electrode and the negative electrode; the aforementioned electrolyte, the positive electrode, the negative electrode and at least a portion of the diaphragm are immersed in the electrolyte. The lithium battery has a long cycle life and high safety, and because star-shaped ether compounds are added to the electrolyte used, there are fewer restrictions on the positive electrode material. In addition to low-potential lithium iron phosphate, positive electrode materials with higher potential (such as lithium cobalt oxide, ternary positive electrode materials, etc.) can also be used, and the scope of application is wider.

[0085] The embodiments of the present application are described in detail below.

[0086] Example 1

[0087] Preparation of tris(2,2,3,3-tetrafluoropropyl)orthoformate (S1)

[0088]

[0089] 10 ml of 2,2,3,3-tetrafluoropropanol was added to a round-bottom flask, and then 1 g of sodium was cut into slices and slowly added to the round-bottom flask and stirred at room temperature for 30 min. Subsequently, 1 ml of freshly distilled chloroform was added and stirred at room temperature for 1 h. Finally, it was heated to 50 ° C and stirred for 48 h. Tris(2,2,3,3-tetrafluoropropyl)orthoformate (S1) was obtained by distillation with a yield of 78%.

[0090] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 6.46 (s, 3H), 3.67 (s, 6H), 5.10 (s, 1H).

[0091] Example 2

[0092] Preparation of Fluorinated Alkyl Substituted 1,2,4-Butanetriol (S2)

[0093]

[0094] 1,1,2,2-tetrafluoroiodoethane (4 eqv.) and 1,2,4-butanetriol (1 eqv.) were added to a round-bottom flask and mixed, and then an excess of potassium carbonate and a catalytic amount of potassium iodide were added, followed by the addition of DMF solvent, and argon was introduced into the mixed solution for 15 min, and then the temperature was raised to 70° C. under argon protection for 48 h. The solution after the reaction was washed with water, extracted, and distilled under reduced pressure to obtain S2 with a yield of 63%.

[0095] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 6.52 (s, 3H), 3.60 (s, 1H), 3.40 (m, 2H), 3.37 (m, 2H), 1.64 (q, 2H).

[0096] Example 3

[0097] Preparation of Fluorinated Alkyl Substituted 1,2,4-Butanetriol (S3)

[0098]

[0099] 2,2,3,3-tetrafluoropropanol (10 eqv.) was added to a round-bottom flask, and then sodium (1 eqv.) was cut into pieces and slowly added to the round-bottom flask and stirred at room temperature for 30 min, followed by adding freshly distilled chloroform (0.4 eqv.) and stirring at room temperature for 24 h, and distilling to obtain the intermediate product 5-chloro-1,1,2,2,8,8,9,9-octafluoro-3,5-heptanediol with a yield of 57%. The product was then added to a propanol solution containing sodium propoxide and heated to 50°C for reaction for 48 hours, washed with water, and distilled to obtain the product S3 with a yield of 80%.

[0100] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 6.46 (s, 2H), 5.55 (s, 1H), 3.69 (s, 4H), 3.55 (t, 4H), 3.4 (s, 3H)

[0101] Example 4

[0102] Preparation of compound S4

[0103] Synthesis steps refer to the method in Example 2, the raw materials used are

[0104] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 6.02 (s, 3H), 3.42 (t, 6H), 1.38 (dd, 6H), 1.20 (dd, 1H).

[0105] Example 5

[0106] Preparation of compound S5

[0107] Synthesis steps Referring to the method in Example 3, firstly, carbon tetraiodide and 1,1,2,2-tetrafluoroethanol are reacted to obtain an intermediate product Afterwards and The reaction yields compound S5.

[0108] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 6.02 (s, 3H), 5.48 (t, 1H), 3.86 (s, 2H), 3.73 (d, 2H).

[0109] Example 6

[0110] Preparation of compound S6

[0111]

[0112] 1,1,2,2-tetrafluoroiodoethane (4 eqv.) and pentaerythritol (1 eqv.) were added to a round-bottom flask, mixed by adding a small amount of dry DMF, then adding an excess of potassium carbonate and a catalytic amount of potassium iodide, followed by adding DMF solvent, and passing argon gas into the mixed solution for 15 minutes, and then the reaction temperature was raised to 70°C under argon protection for 18 hours. The reacted solution was washed with water, extracted, and distilled under reduced pressure to obtain an intermediate product with a yield of 43%. Then the intermediate product obtained in the previous step and 2-iodo-1,1,2',2'-tetrafluoroethyl ether were reacted in a DMF solution with potassium carbonate to obtain compound S6 with a yield of 82%.

[0113] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 6.52 (s, 3H), 5.48 (t, 1H), 3.86 (s, 2H), 3.73 (d, 2H), 3.42 (m, 8H).

[0114] Example 7

[0115] Preparation of compound S7

[0116] Synthesis steps refer to the method in Example 2, the raw materials used are

[0117] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 6.46 (s, 2H), 5.55 (s, 1H), 4.49 (s, 2H), 3.67 (d, 4H), 3.54 (t, 4H).

[0118] Example 8

[0119] Preparation of compound S8

[0120] Synthesis steps refer to the method in Example 2, the raw materials used are

[0121] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 6.46 (s, 2H), 5.55 (s, 1H), 4.49 (s, 2H), 3.86 (s, 2H), 3.67 (t, 4H).

[0122] Example 9

[0123] Preparation of compound S9

[0124]

[0125] As shown in the figure above, two raw materials, excess potassium carbonate and catalytic amount of potassium iodide were added to a round-bottom flask, and then DMF solvent was added. Argon was passed into the mixed solution for 15 minutes, and then the temperature was raised to 70°C under argon protection for 48 hours. The solution after the reaction was washed with water, extracted, and separated by column chromatography to obtain compound S9 with a yield of 58%.

[0126] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 7.15~7.3 (m, 12H), 3.38 (dd, 6H), 2.4 (m, 1H).

[0127] Example 10

[0128] Preparation of compound S10

[0129]

[0130] 4-(Tosyloxy)-fluorobenzene (4 eqv.) and pentaerythritol (1 eqv.) were added to a round-bottom flask and purged with argon for 15 min. Potassium carbonate (5 eqv.) and a catalytic amount of potassium iodide were then added and heated to 70°C for 48 h. The crude product was then washed with water and extracted with dichloromethane to obtain the crude product. The product tri(4-fluorophenyl)orthoformate (S9) was separated by column chromatography with a yield of 45%.

[0131] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 7.15~7.3 (m, 16H), 5.92 (dd, 8H).

[0132] Embodiment 11

[0133] Preparation of compound S11

[0134]

[0135] 4-Fluoroiodomethylbenzene (4 eqv.) and 1,2,4-butanetriol (1 eqv.) were mixed in a round-bottom flask, and then an excess of potassium carbonate and a catalytic amount of potassium iodide were added, followed by the addition of DMF solvent, and argon was introduced into the mixed solution for 15 min, and then the temperature was raised to 90°C under argon protection for 48 h. The solution after the reaction was washed with water, extracted, and separated by column chromatography to obtain the product compound S11 with a yield of 68%.

[0136] Product H NMR spectrum: 1H NMR (400MHz, CDCl3) δ (ppm): 7.10 ~ 7.42 (m, 12H), 4.63 (s, 6H), 3.60 (d, 2H), 3.40 (m, 1H), 3.35 (m, 2H), 1.64 (m, 1H).

[0137] Example 12

[0138] Preparation of compound S12

[0139] The synthesis steps were as in Example 9, with pentaerythritol and p-trifluoromethylbenzyl alcohol being used as raw materials.

[0140] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 7.72 (s, 8H), 4.63 (s, 8H), 5.87 (dd, 8H).

[0141] Embodiment 13

[0142] Preparation of compound S13

[0143] Synthesis steps refer to the method in Example 9, the raw materials used are

[0144] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 3.98 (dd, 6H), 3.05 (m, 1H).

[0145] Embodiment 14

[0146] Preparation of compound S14

[0147] Synthesis steps Referring to the method in Example 9, firstly, the raw material pentaerythritol and p-iodofluorobenzene are reacted to obtain the intermediate product Afterwards and The reaction afforded compound S14.

[0148] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 7.47 (d, 6H), 6.79 (d, 6H), 6.03 (dd, 2H), 5.92 (dd, 6H).

[0149] Embodiment 15

[0150] Preparation of compound S15

[0151] Synthesis steps refer to the method in Example 9, the raw materials used are and 4-iodotrifluoromethylbenzene.

[0152] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 7.47 (d, 6H), 6.79 (d, 6H), 3.89 (dd, 6H), 2.97 (m, 1H).

[0153] Example 16

[0154] Preparation of compound S16

[0155] The synthesis steps were based on the method in Example 9, with pentaerythritol and 2,4,6-tris(trifluoromethyl)-iodobenzene as raw materials.

[0156] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 7.53 (s, 8H), 5.67 (dd, 8H).

[0157] Embodiment 17

[0158] Preparation of compound S17

[0159] Synthesis steps refer to the method in Example 3, the raw materials used are and bromoform.

[0160] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 3.52 (t, 12H), 5.55 (s, 1H).

[0161] Embodiment 18

[0162] Preparation of compound S18

[0163] Synthesis steps refer to the method in Example 3, the raw materials used are and bromoform.

[0164] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 6.51 (s, 3H), 3.86 (s, 6H), 5.10 (s, 1H).

[0165] Embodiment 19

[0166] Preparation of compound S19

[0167] Synthesis steps refer to the method in Example 3, the raw materials used are and triiodomethane.

[0168] Product H NMR spectrum: 1H NMR (400MHz, CDCl3) δ (ppm): 5.48 (t, 3H), 3.73 (d, 6H), 3.54 (t, 12H), 5.24 (s, 1H).

[0169] Embodiment 20

[0170] Preparation of compound S20

[0171] Synthesis steps refer to the method in Example 3, the raw materials used are

[0172] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 6.02 (s, 4H), 3.37 (t, 8H), 1.38 (dd, 8H).

[0173] Embodiment 21

[0174] Preparation of compound S21

[0175] Synthesis steps refer to the method in Example 3, the raw materials are pentaerythritol and

[0176] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 3.86 (s, 8H), 3.29 (s, 8H).

[0177] Embodiment 22

[0178] Preparation of compound S22

[0179] Synthesis steps refer to the method in Example 3, the raw materials are pentaerythritol and

[0180] Product H NMR spectrum: 1 H NMR (400MHz, CDCl3) δ (ppm): 5.55 (t, 4H), 3.73 (d, 8H), 3.58 (t, 16H), 3.48 (dd, 8H).

[0181] Example 23-Example 44 and Comparative Example 1

[0182] The formulas of the electrolytes in Examples 23 to 30 are shown in Table 1 below, the formulas of the electrolytes in Examples 31 to 36 are shown in Table 2 below, and the formulas of the electrolytes in Examples 37 to 44 and Comparative Example 1 are shown in Table 3 below.

[0183] Table 1

[0184]

[0185]

[0186] Table 2

[0187]

[0188] Table 3

[0189]

[0190] Performance Testing:

[0191] Initial discharge capacity:

[0192] The electrolyte prepared as above is applied to the laminated battery as an electrolyte, and the electrochemical properties of the laminated battery are tested using a blue battery pack (the test results are listed in Tables 1 and 2). The laminated battery is charged and discharged between 3.0V and 4.4V at a rate of 0.05C (calculated as the positive electrode) for the first cycle of lithium metal, and the capacity exerted by lithium cobalt oxide is calculated, which is the initial discharge capacity. For subsequent charge and discharge cycles, a rate of 0.5C (calculated as the positive electrode) is used. At the end of each 0.5C charge of the battery, a trickle current of 0.05C is used. Between each charge and discharge, the battery is kept in an open circuit state for 5 minutes.

[0193] Among them, the laminated battery preparation method is as follows: 98% by weight of lithium cobalt oxide as a positive electrode active material, 1% by weight of carbon black as a conductive agent, and 1% by weight of polyvinylidene fluoride (PVDF) as a binder are added to N-methyl-2-pyrrolidone (NMP) as a solvent to prepare a positive electrode slurry. The positive electrode slurry is coated on an aluminum (Al) current collector with a thickness of about 50 μm to form a positive electrode film, and then dried and rolled to prepare a positive electrode. Lithium metal is coated on a copper (Cu) film as a negative electrode collector with a thickness of about 25 μm, and then a roller press is used to complete the preparation of the negative electrode. The above-mentioned positive electrode is cut into a positive electrode sheet of 44×23 mm in size, and the copper foil coated with lithium metal is cut into a negative electrode sheet of 45×24 mm in size. The prepared positive and negative electrodes and a separator composed of three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP) are used to prepare a soft-pack battery by a lamination method, and then the prepared electrolyte is injected into the battery pack to complete the preparation of the lithium battery.

[0194] The cycle performance test results of the batteries in Example 23, Example 30, Example 36, Example 40 and Example 43 are shown in the graphs respectively. Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 The cycle performance test results of the battery in Comparative Example 1 are shown in FIG. Figure 6. According to the test results, when the star-shaped ether compounds in the present application are added in equal amounts to the ether-based or carbonate-based electrolyte, the cycle performance and capacity of the lithium battery are better, and the cycle stability is also improved. Compared with the application of carbonate-based electrolytes (Comparative Example 1) of traditional lithium-ion batteries in lithium batteries, the addition of star-shaped ether compounds to ether-based or fluoroether-based electrolytes can significantly improve the cycle performance and capacity of lithium batteries.

[0195] Coulombic efficiency:

[0196] The 500 μm lithium sheet is a 16π-sized disc, the copper foil is cut into a 17π-sized disc, and the three-layer diaphragm composed of polypropylene / polyethylene / polypropylene (PP / PE / PP) is cut into a 19π-sized disc. The preparation method of the button battery is as follows: the diaphragm is placed between the positive electrode and the negative electrode, the electrolyte system obtained is filled between the three, and the system is packaged and compacted to assemble into a CR2032-type button battery.

[0197] The button cells prepared as above were tested for electrochemical performance using a blue battery pack (the test results are listed in Tables 1 and 2). Use a current density of 2mA / ce (calculated based on the negative electrode area) to discharge for 2 hours, then use a current density of 2mA / ce (calculated based on the negative electrode area) to charge to 1V, then use a current density of 2mA / ce (calculated based on the negative electrode area) to discharge for 2 hours, and after depositing a certain amount of lithium on the copper foil surface, use a current density of 2mA / ce (calculated based on the negative electrode area) to perform a charge and discharge cycle of 30 minutes for ten weeks. After the cycle is completed, use a current density of 2mA / ce (calculated based on the negative electrode area) to charge the battery to 1V, and calculate the coulombic efficiency of the electrolyte to lithium metal based on the capacity. The coulombic efficiency test result graphs of the batteries in Example 28, Example 36 and Example 37 are shown in Figures 1 and 2. Figure 7 , Figure 8 and Fig. 9 According to the test results, by adding the star-shaped ether compound of the present application to an ether-based or fluoroether-based electrolyte, the coulombic efficiency of the electrolyte provided by the present application for lithium is improved.

[0198] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0199] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A star-shaped ether compound, characterized in that: Has one of the following structures:

2. An electrolyte, characterized in that: include: Lithium salts; Organic solvents; as well as The star-shaped ether compound according to claim 1.

3. The electrolyte according to claim 2, characterized in that The molar ratio of the lithium salt, the organic solvent and the star-shaped ether compound is 1-1.5:1-12:0.01-3.

5.

4. The electrolyte according to claim 2, characterized in that Satisfy at least one of the following conditions: The lithium salt is selected from at least one of lithium phosphates, lithium borates, lithium boron cluster compounds, lithium imine salts, lithium aluminates, lithium heterocyclic anion salts, lithium halides, and lithium sulfonates; The organic solvent includes an ether compound or an ester compound; Wherein, the ether compound comprises at least one of cyclic ether, linear ether and fluorinated ether; The ester compound includes at least one of a linear carbonate, a cyclic carbonate and a phosphate.

5. The electrolyte according to claim 4, characterized in that Satisfy at least one of the following conditions: The lithium salt is selected from at least one of lithium trifluoromethanesulfonate, lithium bistrifluoromethanesulfonyl imide, lithium bisfluorosulfonyl imide, lithium hexafluorophosphate, lithium hexafluoroarsenide, lithium difluorophosphate, lithium tetrafluoroborate, lithium difluorooxalatoborate, lithium dioxalatoborate, and lithium perchlorate; The ether compound includes a cyclic ether and a linear ether, and the volume ratio of the linear ether to the cyclic ether is 1-5:5-9; The cyclic ether includes at least one of 1,3-dioxolane, 1,4-dioxane, tetrahydrofuran, tetrahydropyran and propylene oxide; The linear ether includes at least one of methyl glycol dimethyl ether, methyl glycol diethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol methyl ethyl ether, tert-butyl methyl ether, tert-butyl ethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether and dipropylene glycol dimethyl ether; The fluorinated ethers include bis-2,2-trifluoroethyl ether, 1,1,1,2,3,3-hexafluoropropyl-2,2,2-trifluoroethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, nonafluorobutyl methyl ether, nonafluorobutyl ethyl ether, nonafluorobutyl propyl ether, 1,1,1,2,2,3,3,4,4-nonafluoroisobutyl methyl ether, n-butyl-1,1,2,2-tetrafluoroethyl ether, 2,2,3,3,3-pentafluoropropyl methyl ether, 2,2,3,3,3-pentafluoropropyl methyl ether, 1 , at least one of 1,2,3,3,3-hexafluoropropyl ethyl ether, 1,1,2,2-tetrafluoroethyl ether, 1,1,2,2-tetrafluoroethyl methyl ether, 1,1,1,1',1',1',2-hexafluoroisobutyl difluoromethyl ether, 2,2,3,3-tetrafluoropropyl difluoromethyl ether, hexafluoroisopropyl methyl ether, 1,1,2,3,3,3-hexafluoropropyl difluoromethyl ether, tris(2,2,2-trifluoroethyl)orthoformate, 1,1,2,2-tetrafluoroethyl-1H,1H,5H-octafluoropentyl ether, 1,1,2,2-tetrafluoroethyl ethyl ether and trifluoroethyl dodecafluorohexyl ether; The cyclic carbonate includes at least one of ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate and vinylene carbonate and halides thereof; The linear carbonate is selected from at least one of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate and methyl propyl carbonate; The phosphate ester is selected from at least one of trimethylphosphine oxide, triethylphosphine oxide, tripropylphosphine oxide, triphenylphosphine oxide, diethyl methylphosphonate, dimethyl methylphosphonate, diphenyl methylphosphonate, bis(2,2,2-trifluoroethyl)methylphosphonate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate and ethylmethylphenyl phosphate.

6. The electrolyte according to claim 2, characterized in that The organic solvent further comprises at least one of an organic acid ester and a nitrile compound; The organic acid ester comprises at least one of methyl acetate, ethyl acetate, propyl acetate, ethyl propionate, propyl propionate, methyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-valerolactone and ε-caprolactone; The nitrile compound includes at least one of acetonitrile, propionitrile, butyronitrile, valeronitrile, hexanenitrile, heptanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, benzyl cyanide, 2-fluorobenzoyl cyanide and 4-fluorobenzoyl cyanide.

7. A lithium battery, characterized in that: include: positive electrode; negative electrode; A separator, the separator being located between the positive electrode and the negative electrode; The electrolyte according to any one of claims 2 to 6, wherein at least a portion of the positive electrode, the negative electrode, and the separator are immersed in the electrolyte.

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