CN115611714A

CN115611714A - Star-shaped ether compound, electrolyte and lithium battery

Info

Publication number: CN115611714A
Application number: CN202110734841.5A
Authority: CN
Inventors: 陈嵩; 郭姿珠; 马永军; 谢静; 袁涛
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2023-01-17

Abstract

The application provides a star-shaped ether compound, an electrolyte and a lithium battery, wherein the star-shaped ether compound has the following structural formula:

Description

Star-shaped ether compound, electrolyte and lithium battery

Technical Field

The application relates to the technical field of lithium batteries, in particular to a star-shaped ether compound, electrolyte and a lithium battery.

Background

The lithium metal has a low density(0.59g/cm ³ ) High theoretical specific capacity (3860 mAh/g) and low reduction potential (-3.04Vvs ⁺ /H ₂ ) The lithium ion battery is considered as an ideal anode material of the next generation lithium battery, but has some problems in the using process: on one hand, lithium ions are continuously deposited on the surface of lithium metal in charge-discharge circulation, and the concentration gradient of local lithium ions causes different liquid-phase mass transfer flow, so that lithium dendrites are generated, and the problems of short circuit and the like are finally caused; on the other hand, lithium dendrites protruding from the surface of the negative electrode continuously grow due to the uneven deposition of lithium ions on the surface of lithium metal during charge and discharge cycles, resulting in the generation of "dead lithium" and reducing the capacity of the negative electrode.

Thus, the related art of the present lithium battery still needs to be improved.

Content of application

The present application is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the application aims to provide a star-shaped ether compound, an electrolyte and a lithium battery.

In one aspect of the present application, a star ether compound is provided. According to embodiments of the present application, the star ether compounds have the following structural formula:

wherein X ₁ 、X ₂ 、X ₃ Each independently is a bond or- (CH) ₂ ) _a -；

R ₄ Is H or- (CH) ₂ ) _b -O-R ₅ ；

R ₁ 、R ₂ 、R ₃ And R ₅ Each independently selected from the group consisting of 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;

the substituents in the substituted alkyl, substituted haloalkyl, substituted phenyl, substituted halophenyl, substituted benzyl and substituted halobenzyl groups are each independently selected from the group consisting of alkyl, haloalkyl, alkoxy, haloalkoxy, alkoxy-substituted alkoxy, alkoxy-substituted haloalkoxy, haloalkoxy-substituted alkoxy, haloalkoxy-substituted haloalkoxy, acyl, cyanoalkoxy and cyano;

wherein R is ₁ 、R ₂ 、R ₃ And R ₅ Contains halogen, the halogen comprises 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.

The star-shaped ether compound has the characteristics of easiness in preparation and storage, non-flammability and industrialization potential, and when the star-shaped ether compound is used for an electrolyte, the star-shaped molecular structure can reduce intermolecular acting force, optimize the solvation structure and degree in the electrolyte, further reduce the viscosity of the electrolyte, and increase the wettability of the electrolyte on a pole piece; when the electrolyte is used for a lithium battery, lithium ions can rapidly move to a negative electrode, and the lithium ions are uniformly released on the surface of the negative electrode and deposited, so that the safety problem caused by the growth of lithium dendrites is solved; meanwhile, the electrolyte is beneficial to forming compact complex clusters between lithium ions in the electrolyte and a solvent, and can be uniformly distributed on the surface of a negative electrode under the action of an electric field during charging, so that a uniform and compact SEI (solid electrolyte interphase) film can be formed on the surface of the negative electrode, and the electrolyte also has high stability, wettability and safety on a positive electrode.

In another aspect of the present application, an electrolyte is provided. According to an embodiment of the application, the electrolyte comprises: a lithium salt; an organic solvent; and the star ether compounds described above. In the electrolyte, the star-shaped ether compound is added, so that the intermolecular acting force can be reduced, the solvation structure is optimized, the viscosity of the electrolyte is reduced, and the wettability of the electrolyte on a pole piece is improved; when the lithium ion battery is used for a lithium battery, lithium ions can rapidly move to the negative electrode, and the lithium ions are uniformly released and deposited on the surface of the negative electrode, so that the safety problem caused by the growth of lithium dendrites is solved; and lithium ions in the electrolyte can form a compact complex cluster with a solvent, and can be uniformly distributed on the surface of the negative electrode under the action of an electric field during charging, so that a uniform and compact SEI (solid electrolyte interphase) film can be formed on the surface of the negative electrode, and the electrolyte can also have high stability, wettability and safety for the positive electrode.

In yet another aspect of the present application, a lithium battery is provided. According to an embodiment of the present application, the lithium battery includes: a positive electrode; a negative electrode; a separator between the positive electrode and the negative electrode; at least a portion of the aforementioned electrolyte, the positive electrode, the negative electrode, and the separator is immersed in the electrolyte. The lithium battery has long cycle life and high safety, and the star-shaped ether compound is added in the adopted electrolyte, so that the limit on the anode material is small, besides low-potential lithium iron phosphate, the anode material with higher potential (such as lithium cobaltate, ternary anode material and the like) can also be used, and the application range is wider.

Drawings

FIG. 1 is a graph showing the results of a cycle performance test of the battery of example 23.

FIG. 2 is a graph showing the results of the cycle performance test of the battery of example 30.

FIG. 3 is a graph showing the results of the cycle performance test of the battery of example 36.

Fig. 4 is a graph showing the results of the cycle performance test of the battery of example 40.

Fig. 5 is a graph showing the results of the cycle performance test of the battery of example 43.

Fig. 6 is a graph showing the results of cycle performance tests of the battery in comparative example 1.

Fig. 7 is a graph of the coulombic efficiency test results for the battery of example 28.

Fig. 8 is a graph of coulombic efficiency test results for the cells of example 36.

Fig. 9 is a graph showing the results of coulombic efficiency tests on the cells of example 37.

Detailed Description

Embodiments of the present application are described in detail below. The following embodiments are described as illustrative only and are not to be construed as limiting the present application. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are conventional products which are commercially available, and are not indicated by manufacturers.

wherein, X ₁ 、X ₂ 、X ₃ Each independently is a bond or- (CH) ₂ ) _a -；

R ₄ Is H and is- (CH) ₂ ) _b -O-R ₅ ；

the substituents in the above substituted alkyl, substituted haloalkyl, substituted phenyl, substituted halophenyl, substituted benzyl and substituted halobenzyl are each independently selected from the group consisting of alkyl, haloalkyl, alkoxy, haloalkoxy, alkoxy-substituted alkoxy, alkoxy-substituted haloalkoxy, haloalkoxy-substituted alkoxy, haloalkoxy-substituted haloalkoxy, acyl, cyanoalkoxy and cyano;

The star-shaped ether compound has the characteristics of easiness in preparation and storage, non-flammability and industrialization potential, and when the star-shaped ether compound is used for an electrolyte, the star-shaped molecular structure can reduce intermolecular acting force, optimize the solvation structure and degree in the electrolyte, further reduce the viscosity of the electrolyte, and increase the wettability of the electrolyte on a pole piece; when the electrolyte is used for a lithium battery, lithium ions can rapidly move to a negative electrode, and the lithium ions are uniformly released on the surface of the negative electrode and deposited, so that the safety problem caused by the growth of lithium dendrites is solved; meanwhile, the electrolyte is beneficial to forming compact complex clusters between lithium ions in the electrolyte and a solvent, and can be uniformly distributed on the surface of a negative electrode under the action of an electric field during charging, so that a uniform and compact SEI (solid electrolyte interphase) film can be formed on the surface of the negative electrode, and the electrolyte can also have high stability, wettability and safety on a positive electrode.

It is to be understood that the specific meanings of certain descriptive terms and terms used herein are as follows:

when a =0, X is ₁ 、X ₂ Or X ₃ Is a chemical bond, O and C are directly connected to each other, to

For example, when a =0,

the actual structure is

b =0, - (CH) ₂ ) _b -O-R ₅ Has the actual structure of-O-R ₅ 。

In each substituent and group

Represents a molecular chain linked to the corresponding position in each substituent and group, "-" in each substituent and group represents a position linked to other groups.

"substituted or unsubstituted alkyl" refers to unsubstituted alkyl (-C) _n H _2n+1 N is a positive integer) or at least one HAlkyl (-C) substituted by a substituent R _n H _m R _p P is a positive integer, m is a natural number, and m + p =2n + 1).

Substituted or unsubstituted phenyl means unsubstituted phenyl (

-C ₆ H ₅ ) Or phenyl (-C) in which at least one H is substituted by a substituent R ₆ H _c R _d D is a positive integer, c is a natural number, and c + d = 5). Here, it is to be noted that ₆ H _c R _d The 6 carbon atoms shown in (a) do not include carbon atoms in the substituent R.

Substituted or unsubstituted benzyl means an unsubstituted benzyl group (

-C ₇ H ₇ ) Or benzyl (-C) with at least one H substituted by a substituent R ₇ H _e R _f Is a positive integer, e is a natural number, and e + f = 7). Here, it is to be noted that-C ₇ H _e R _f The 7 carbon atoms shown in (a) do not include carbon atoms in the substituent R.

"haloalkyl" refers to an alkyl (-C) group in which at least one H is substituted with a halogen _n H _m Y _q Y is halogen, q is a positive integer, m + q =2n +1, "substituted or unsubstituted haloalkyl" means haloalkyl (i.e., unsubstituted haloalkyl), or haloalkyl (-C) wherein at least one H is substituted with a substituent R _n H _m R _p Y _q M + p + q =2n + 1) (i.e., substituted haloalkyl).

"Halophenyl" refers to a phenyl group (-C) wherein at least one H is substituted with a halogen ₆ H _c Y _g G is a positive integer, and C + g = 5), "substituted or unsubstituted halophenyl" refers to a halophenyl group (i.e., unsubstituted halophenyl group), or a halophenyl group (-C) in which at least one H is substituted with a substituent R ₆ H _c R _d Y _g C + d + g = 5) (i.e., substituted halophenyl). Here, it is to be noted that-C ₆ H _c R _d Y _g The 6 carbon atoms shown in (a) do not include carbon atoms in the substituent R.

"halobenzyl" means a benzyl group (-C) having at least one H substituted with a halogen ₇ H _e Y _h H is a positive integer, and e + H = 7), "substituted or unsubstituted halobenzyl" refers to halobenzyl (i.e., unsubstituted halobenzyl), or halobenzyl (-C) wherein at least one H is substituted with a substituent R ₇ H _e R _f Y _h E + f + h = 7) (i.e. substituted halobenzyl). Here, it is to be noted that-C ₇ H _e R _f Y _h The 7 carbon atoms shown in (a) do not include carbon atoms in the substituent R.

"alkoxy" means-OC _i H _2i+1 And i is a positive integer.

"haloalkoxy" means an alkoxy group (-OC) in which at least one H is substituted by halogen _i H _j Y _k K is a positive integer, j + k =2i + 1).

"alkoxy-substituted alkoxy" refers to an alkoxy group (-OC) wherein at least one H is substituted by an alkoxy group _i H _j Z _r Z is-OC _i H _2i+1 R is a positive integer, j + r =2i + 1)

"cyano" means-CN.

"cyanoalkoxy" refers to an alkoxy group (-OC) wherein at least one H is replaced by a cyano group _i H _j W _l W is-CN, l is a positive integer, j + l =2i + 1).

"acyl" refers to

Ra is H or alkyl.

“R ₁ 、R ₂ 、R ₃ And R ₅ Independently represents 8230, or R ₁ 、R ₂ 、R ₃ And R ₅ The groups (b) may be the same or different, and may be selected from the group defined in the present application.

The above substituents R are each independently an alkyl group, a haloalkyl group, an alkoxy group, a haloalkoxy group, an alkoxy-substituted alkoxy group, an alkoxy-substituted haloalkoxy group, a haloalkoxy-substituted alkoxy group, a haloalkoxy-substituted haloalkoxy group, an acyl group, a cyanoalkoxy group, and a cyano group.

According to embodiments of the present application, R ₁ 、R ₂ 、R ₃ And R ₅ Each independently selected from substituted or unsubstituted C _1-6 Alkyl, substituted or unsubstituted C _1-6 A haloalkyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted halophenyl group, a substituted or unsubstituted benzyl group, and a substituted or unsubstituted halobenzyl group; c substituted as described above _1-6 Alkyl, substituted C _1-6 The substituents in haloalkyl, substituted phenyl, substituted halophenyl, substituted benzyl and substituted halobenzyl are each independently selected from C _1-6 Alkyl radical, C _1-6 Haloalkyl, C _1-6 Alkoxy radical, C _1-6 Haloalkoxy, C _1-6 Alkoxy-substituted C _1-6 Alkoxy radical, C _1-6 Alkoxy-substituted C _1-6 Haloalkoxy, C _1-6 Haloalkoxy substituted C _1-6 Alkoxy radical, C _1-6 Haloalkoxy substituted C _1-6 Haloalkoxy, C _1-6 Acyl radical, C _1-6 Cyanoalkoxy and cyano, a is an integer from 0 to 6, and b is an integer from 0 to 6.

According to embodiments of the present application, R ₁ 、R ₂ 、R ₃ And R ₅ Each independently selected from C _1-6 Fluoroalkyl, C _1-4 Alkoxy-substituted C _1-4 Alkyl radical, C _1-4 Fluoroalkoxy-substituted C _1-4 Alkyl radical, C _1-4 Fluoroalkoxy-substituted C _1-4 Fluoroalkyl, C _1-4 Cyanoalkoxy-substituted C _1-4 Alkyl radical, C _1-4 Cyanoalkoxy-substituted C _1-4 Fluoroalkyl, fluorophenyl, C _1-4 Fluoroalkyl-substituted phenyl, C _1-4 Fluoroalkyl substituted benzyl, first substituent substituted C _1-4 Alkyl and C substituted by a first substituent _1-4 A fluoroalkyl group; wherein the first substituent is C _1-4 Fluoroalkoxy-substituted C _1-4 Alkoxy radical, C _1-4 Fluoroalkoxy-substituted C _1-4 Fluoroalkoxy radical, C _1-4 Alkoxy-substituted C _1-4 Fluoroalkoxy and C _1-4 Alkoxy-substituted C _1-4 Alkoxy, a is an integer of 0 to 2, and b is an integer of 0 to 2.

In addition, "C" above _1-4 "and" C _1-6 "refers to the number of carbon atoms in a group, e.g. C _1-4 The alkyl group is an alkyl group having 1 to 4 carbon atoms, and specifically may be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a tert-butyl group, and C _1-6 The alkyl refers to an alkyl group having 1 to 6 carbon atoms, and other similar description meanings are the same as above, and redundant description thereof is omitted.

According to embodiments herein, the halogen may be fluorine. Therefore, the star ether compound can improve the stability of a positive electrode material at a positive electrode terminal, and can form a stable, compact, high-mechanical-strength and high-surface-energy lithium fluoride-rich SEI layer at a negative electrode terminal. Compared with the fluoroether in the related technology, the fluorine substitution in the star-shaped ether compound has the characteristics of higher modifiability and higher fluorination degree, and the ratio of C-H bonds in the star-shaped ether compound can be further reduced, so that the safety of the electrolyte is improved. Meanwhile, the star-shaped ether compound can be subjected to fluorination modification in different degrees according to different solvent strategies, so that the star-shaped ether compound has better electrochemical performance, and a CEI layer and an SEI layer rich in LiF are easier to form.

According to some embodiments of the application, R ₁ 、R ₂ 、R ₃ And R ₅ Each independently selected from the group consisting of:

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 requirement, specifically, a part of H in the star-shaped ether compound may be substituted by halogen, or all H in the star-shaped compound may be substituted by halogen. In some embodiments, R ₁ 、R ₂ And R ₃ In each case containing the halogen or R ₁ 、R ₂ 、R ₃ And R ₅ All contain the halogen. The chemical structures of the chains in the star ether compounds can be the same or different, and in some specific embodiments, R is ₁ 、R ₂ And R ₃ Are the same radicals or R ₁ 、R ₂ 、R ₃ And R ₅ Are the same group. Specifically, the halogen content in the star-shaped compound is increased within a certain range, so that an SEI film can be formed more favorably, and the service performance of a lithium battery is further improved; and R is ₁ 、R ₂ And R ₃ Are the same radicals or R ₁ 、R ₂ 、R ₃ And R ₅ The star-shaped compound has a symmetrical structure due to the same groups, and is convenient to prepare while having a better using effect.

According to some embodiments of the application, X ₁ 、X ₂ 、X ₃ Each independently is- (CH) ₂ ) _a -, and R ₄ Is H, wherein a is 0, 1 or 2. According to other embodiments of the present application, X ₁ 、X ₂ 、X ₃ Each independently is- (CH) ₂ ) _a -, and R ₄ Is- (CH) ₂ ) _b -O-R ₅ Wherein a is 1 or 2, b is 0, 1 or 2. Therefore, the star ether compound has better use effect and is easier to prepare.

According to some specific examples of the present application, the star ether-based compound includes at least one of:

in another aspect of the present application, there is provided a method for preparing the star ether compounds as described above. According to an embodiment of the application, the method comprises: mixing substance A and substanceB reaction to obtain star ether compound

Wherein substance A is selected from

Substance B is selected from R ₁ -Y ₁ 、R ₂ -Y ₂ 、R ₃ -Y ₃ And R ₅ -Y ₅ Wherein, Z ₁ 、Z ₂ 、Z ₃ And Z ₄ is-OH and Y ₁ 、Y ₂ 、Y ₃ And Y ₅ Each independently selected from halogen and-OTs (p-toluenesulfonyloxy) or Z ₁ 、Z ₂ 、Z ₃ And Z ₄ Is halogen and Y ₁ 、Y ₂ 、Y ₃ And Y ₅ Each independently selected from-ONa or-OTs (p-toluenesulfonyloxy); x ₁ 、X ₂ 、X ₃ 、R ₁ 、R ₂ 、R ₃ 、R ₄ And R ₅ And b are identical to the previous definitions and will not be described in detail herein.

According to some embodiments of the application, the method may be performed by at least one of the following synthetic routes:

specifically, when R is ₄ When is H, can be

And R ₁ -Y ₁ 、R ₂ -Y ₂ And R ₃ -Y ₃ Reacting to obtain a product

When R is ₄ Is- (CH) ₂ ) _b -O-R ₅ In time, can make

And R ₁ -Y ₁ 、R ₂ -Y ₂ 、R ₃ --Y ₃ And R ₅ -Y ₅ Reacting to obtain a product

In some embodiments, R ₁ 、R ₂ 、R ₃ And R ₅ Are different groups, in which case the reaction can be carried out stepwise, to

For purposes of illustration, R ₁ -Y ₁ 、R ₂ -Y ₂ 、R ₃ -Y ₃ And R ₅ -Y ₅ Can be stepped with

The reaction, the specific reaction sequence is not particularly limited and may be adjusted according to the actual circumstances, and wherein Y ₁ 、Y ₂ 、Y ₃ And Y ₅ May be the same or different. In other embodiments, R ₁ 、R ₂ 、R ₃ And R ₅ The same groups, in which case the above reaction can be carried out in one step or in steps as required, and in some embodiments, Y ₁ 、Y ₂ 、Y ₃ And Y ₅ Are also identical radicals, it being possible thereby for

Reacting with a substance (e.g. R) ₁ -Y ₁ ) Can obtain

The steps are simpler. In other embodiments, R ₁ 、R ₂ 、R ₃ And R ₅ Partially identical radicalsMoieties being different radicals, with R ₁ 、R ₂ 、R ₃ Are identical radicals, R ₅ And R ₁ 、R ₂ 、R ₃ Different as an example, R ₁ -Y ₁ 、R ₂ -Y ₂ 、R ₃ -Y ₃ Can be combined with

Firstly, carrying out one-step reaction, then obtaining an intermediate product, and reacting the intermediate product with R ₅ -Y ₅ Reaction, wherein Y ₁ 、Y ₂ 、Y ₃ Are identical radicals, and Y ₅ Can be reacted with Y ₁ 、Y ₂ 、Y ₃ The same or different.

Wherein, the reaction between-OH and halogen and-OTs (p-toluenesulfonyloxy), and the reaction between halogen and-ONa or-OTs (p-toluenesulfonyloxy) are classical acid-base reactions, and the specific reaction conditions may be selected according to practical situations, for example, the reaction may be performed by referring to conventional techniques, and are not described herein again.

In another aspect of the present application, an electrolyte is provided. According to an embodiment of the application, the electrolyte comprises: a lithium salt; an organic solvent; and the star ether compounds mentioned above. In the electrolyte, the star-shaped ether compound is added, so that the intermolecular acting force can be reduced, the solvation structure is optimized, the viscosity of the electrolyte is reduced, and the wettability of the electrolyte on a pole piece is improved; when the lithium ion battery is used for a lithium battery, lithium ions can rapidly move to the negative electrode, and the lithium ions are uniformly released and deposited on the surface of the negative electrode, so that the safety problem caused by the growth of lithium dendrites is solved; and lithium ions in the electrolyte can form a compact complex cluster with a solvent, and can be uniformly distributed on the surface of the negative electrode under the action of an electric field during charging, so that a uniform and compact SEI (solid electrolyte interphase) film can be formed on the surface of the negative electrode, and the electrolyte can also have high stability, wettability and safety for the positive electrode.

According to an embodiment of the present application, the lithium salt may be selected from a lithium phosphate, a lithium borate, a lithium boron group clusterAt least one of a compound, an imide salt of lithium, an aluminate salt of lithium, a heterocyclic anion salt of lithium, a halate salt of lithium, a sulfonate salt of lithium, and derivatives thereof. In some embodiments, the lithium salt is selected from lithium trifluoromethanesulfonate (LiTFA), lithium bistrifluoromethylsulfonimide (LiTFSI), lithium bistrifluorosulfonimide (LiFSI), lithium hexafluorophosphate (LiPF) ₆ ) Lithium hexafluoroarsenate (LiAsF) ₆ ) Lithium difluorophosphate (LiPOF) ₂ ) Lithium tetrafluoroborate (LiBF) ₄ ) Lithium difluoroborate (LiODFB), lithium dioxalate borate (LiBOB), lithium perchlorate (LiClO) ₄ ) At least one of (1).

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 embodiments, the organic solvent in the electrolyte is an ester compound. The electrolyte is suitable for lithium or lithium-based alloy cathode batteries.

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 may 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.

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

In some embodiments, the linear ether comprises 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, t-butyl methyl ether, t-butyl ethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether and dipropylene glycol dimethyl ether.

According to the embodiment of the application, when the organic solvent comprises both the linear ether and the cyclic ether, the ratio of the linear ether and the cyclic ether can be flexibly adjusted according to application needs. In some embodiments, the volume ratio of the linear ether to the cyclic ether can be 1 to 5:5-9, specifically 1. In some embodiments, the volume ratio of the linear ether to the cyclic ether can be 1-2:2-3, specifically 1.

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 ester.

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, and vinylene carbonate, and halides thereof.

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

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-trifluoroethyl) methylphosphonate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, and ethylmethylphenyl phosphate.

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 comprises at least one of methyl acetate, ethyl acetate, propyl acetate, ethyl propionate, propyl propionate, methyl propionate, gamma-butyrolactone, gamma-valerolactone, gamma-caprolactone, delta-valerolactone and epsilon-caprolactone; the nitrile compound comprises at least one of acetonitrile, propionitrile, butyronitrile, valeronitrile, capronitrile, enanthonitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluoropropionitrile, phenylacetonitrile, 2-fluorophenylacetonitrile and 4-fluorophenylacetonitrile.

According to the embodiment of the present application, the molar ratio of the lithium salt, the organic solvent and the star-like ether compound is 1 to 1.5, 0.01 to 3.5, specifically 1. Specifically, the specific dosage of the star ether compound can be flexibly adjusted according to actual conditions, and the star ether compound can be applied to various different conditions and batteries within the range, is wide in application range and has a good use effect.

In yet another aspect of the present application, a lithium battery is provided. According to an embodiment of the present application, the lithium battery includes: a positive electrode; a negative electrode; a separator between the positive electrode and the negative electrode; at least a part of the aforementioned electrolyte, the positive electrode, the negative electrode, and the separator is immersed in the electrolyte. The lithium battery has long cycle life and high safety, and the star-shaped ether compound is added in the adopted electrolyte, so that the limit on the anode material is small, besides low-potential lithium iron phosphate, the anode material with higher potential (such as lithium cobaltate, ternary anode material and the like) can also be used, and the application range is wider.

Embodiments of the present application are described in detail below.

Example 1

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

10ml of 2, 3-tetrafluoropropanol was added in the round-bottom flask, then 1g of sodium was cut into pieces and slowly added to the round-bottom flask and stirred at room temperature for 30min, then freshly distilled chloroform was added 1ml and stirred at room temperature for 1h, finally heated to 50 ℃ and stirred for 48h, and the tris (2, 3-tetrafluoropropyl) orthoformate (S1) was obtained by distillation in 78% yield.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):6.46(s,3H),3.67(s,6H),5.10(s,1H).

example 2

Preparation of fluoroalkane-substituted 1,2, 4-butanetriol (S2)

1, 2-tetrafluoroiodoethane (4 eqv.) and 1,2, 4-butanetriol (1 eqv.) are added into a round-bottom flask for mixing, then excessive potassium carbonate and a catalytic amount of potassium iodide are added, then a DMF solvent is added, argon gas is introduced into the mixed solution for 15min, and then the reaction is heated to 70 ℃ under the protection of argon gas for 48h. And washing, extracting and distilling the reacted solution under reduced pressure to obtain S2 with the yield of 63%.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):6.52(s,3H),3.60(s,1H),3.40(m,2H),3.37(m,2H),1.64(q,2H).

example 3

Preparation of fluoroalkane-substituted 1,2, 4-butanetriol (S3)

2,2,3,3-tetrafluoropropanol (10 eq v.) was added in the round-bottom flask, then sodium (1 eq v.) was cut into pieces and slowly added to the round-bottom flask with stirring at room temperature for 30min, followed by addition of freshly distilled chloroform (0.4 eq v.) with stirring at room temperature for 24h, and distillation yielded an intermediate 5-chloro-1,1,2,2,8,8,9,9-octafluoro-3,5-heptanediol with a yield of 57%. Then the product is added into a propanol solution containing sodium propoxide, heated to 50 ℃ for reaction for 48 hours, washed with water and distilled to obtain the product S3 with the yield of 80%.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):6.46(s,2H),5.55(s,1H),3.69(s,4H),3.55(t,4H),3.4(s,3H)

example 4

Preparation of Compound S4

Synthetic procedure the procedure of reference example 2 was followed, starting materials used

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):6.02(s,3H),3.42(t,6H),1.38(dd,6H),1.20(dd,1H).

example 5

Preparation of Compound S5

Synthesis procedure referring to the procedure in example 3, starting materials carbon tetraiodide and 1, 2-tetrafluoroethanol were first reacted to give an intermediate product

Followed by

The reaction gives the compound S5.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):6.02(s,3H),5.48(t,1H),3.86(s,2H),3.73(d,2H).

example 6

Preparation of Compound S6

1, 2-tetrafluoroiodoethane (4 eq v.) and pentaerythritol (1 eq v.) were added in a round bottom flask, mixed by adding a small amount of dry DMF, then added with an excess of potassium carbonate and a catalytic amount of potassium iodide, followed by DMF solvent, and the mixed solution was purged with argon for 15min, followed by reaction under argon atmosphere and heating to 70 ℃ for 18h. And washing, extracting and distilling the reacted solution under reduced pressure to obtain an intermediate product with the yield of 43 percent. Then the intermediate product obtained in the previous step reacts with 2-iodo-1, 2' -tetrafluoroethyl ether in DMF added with potassium carbonate to obtain compound S6 with 82% yield.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):6.52(s,3H),5.48(t,1H),3.86(s,2H),3.73(d,2H),3.42(m,8H).

example 7

Preparation of Compound S7

Synthesis procedure the procedure of example 2 was referenced, starting material used

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):6.46(s,2H),5.55(s,1H),4.49(s,2H),3.67(d,4H),3.54(t,4H).

example 8

Preparation of Compound S8

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):6.46(s,2H),5.55(s,1H),4.49(s,2H),3.86(s,2H),3.67(t,4H).

example 9

Preparation of Compound S9

As shown in the figure, two raw materials, excessive potassium carbonate and a catalytic amount of potassium iodide are added into a round-bottom flask, then DMF solvent is added, argon gas is introduced into the mixed solution for 15min, and then the reaction is heated to 70 ℃ under the protection of argon gas for 48h. And washing the reacted solution with water, extracting, and separating by column chromatography to obtain the compound S9 with the yield of 58%.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):7.15～7.3(m,12H),3.38(dd,6H),2.4(m,1H).

example 10

Preparation of Compound S10

4- (tosyloxy) -fluorinated benzene (4 eq v.) and pentaerythritol (1 eq v.) were added to a round bottom flask and purged with argon for 15min, followed by addition of potassium carbonate (5 eq v.) and a catalytic amount of potassium iodide and heating to 70 ℃ for reaction for 48h, followed by water washing and extraction with dichloromethane to give a crude product, which was isolated by column chromatography to give the product tris (4-fluorophenyl) orthoformate (S9) in 45% yield.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):7.15～7.3(m,16H),5.92(dd,8H).

example 11

Preparation of Compound S11

4-Fluoroiodomethylbenzene (4 eq v.) and 1,2, 4-butanetriol (1 eq v.) were mixed in a round bottom flask, then excess potassium carbonate and catalytic amount of potassium iodide were added, DMF solvent was then added, argon gas was bubbled through the mixed solution for 15min, and then the reaction was warmed to 90 ℃ under argon protection for 48h. And washing the reacted solution with water, extracting, and separating by column chromatography to obtain the product compound S11 with a yield of 68%.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )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).

example 12

Preparation of Compound S12

Synthetic procedure with reference to the procedure in example 9, pentaerythritol and p-trifluoromethylbenzyl alcohol were used as starting materials.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):7.72(s,8H),4.63(s,8H),5.87(dd,8H).

example 13

Preparation of Compound S13

Synthetic procedure the procedure of reference example 9 was followed, starting from

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):3.98(dd,6H),3.05(m,1H).

example 14

Preparation of Compound S14

Synthesis procedure referring to the procedure in example 9, starting with pentaerythritol and p-iodofluorobenzene as starting materials, an intermediate product is obtained

Subsequently and

the reaction yielded compound S14.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):7.47(d,6H),6.79(d,6H),6.03(dd,2H),5.92(dd,6H).

example 15

Preparation of Compound S15

And 4-iodotrifluoromethylbenzene.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):7.47(d,6H),6.79(d,6H),3.89(dd,6H),2.97(m,1H).

example 16

Preparation of Compound S16

Synthetic procedure with reference to the procedure in example 9, pentaerythritol and 2,4, 6-tris (trifluoromethyl) -iodobenzene were used as starting materials.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):7.53(s,8H),5.67(dd,8H).

example 17

Preparation of Compound S17

Synthetic procedure the procedure of reference example 3 was followed, starting materials used

And tribromomethane.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):3.52(t,12H),5.55(s,1H).

example 18

Preparation of Compound S18

Synthesis procedure the procedure of example 3 is referred to, starting materials used

And tribromomethane.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):6.51(s,3H),3.86(s,6H),5.10(s,1H).

example 19

Preparation of Compound S19

And triiodomethane.

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):5.48(t,3H),3.73(d,6H),3.54(t,12H),5.24(s,1H).

example 20

Preparation of Compound S20

Nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):6.02(s,4H),3.37(t,8H),1.38(dd,8H).

example 21

Preparation of Compound S21

Synthesis procedure referring to the procedure in example 3, pentaerythritol and

nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):3.86(s,8H),3.29(s,8H).

example 22

Preparation of Compound S22

Synthesis procedure the procedure of reference example 3 is followed, starting with pentaerythritol and

nuclear magnetic resonance hydrogen spectrum of the product: ¹ H NMR(400MHz,CDCl ₃ )δ(ppm):5.55(t,4H),3.73(d,8H),3.58(t,16H),3.48(dd,8H).

examples 23 to 44 and comparative example 1

The formulations of the electrolytes of examples 23 to 30 are shown in table 1 below, the formulations of the electrolytes of examples 31 to 36 are shown in table 2 below, and the formulations of the electrolytes of examples 37 to 44 and comparative example 1 are shown in table 3 below.

TABLE 1

TABLE 2

TABLE 3

And (4) performance testing:

initial discharge capacity:

the electrolyte prepared as above was applied to a laminated battery as an electrolyte, and the electrochemical performance of the laminated battery was tested using a blue battery (test results are shown in tables 1 and 2). The laminated cell was charged and discharged between 3.0V and 4.4V using a rate of 0.05C (calculated as positive electrode) for the first cycle of lithium metal, and the capacity exerted by lithium cobaltate was calculated as the initial discharge capacity. For the subsequent charge and discharge cycles, a rate of 0.5C (calculated as positive electrode) was 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, it is the cell that is left open for 5 minutes.

The preparation method of the laminated battery comprises the following steps: to N-methyl-2-pyrrolidone (NMP) as a solvent, 98 wt% of lithium cobaltate as a positive electrode active material, 1 wt% of carbon black as a conductive agent, and 1 wt% of polyvinylidene fluoride (PVDF) as a binder were added to prepare a positive electrode slurry. The positive electrode slurry was coated on an aluminum (Al) current collector at a thickness of about 50 μm to form a positive electrode film, and dried and then rolled to prepare a positive electrode. Lithium metal was coated on a copper (Cu) thin film as an anode current collector in a thickness of about 25 μm, followed by completing the preparation of an anode using a roll press. The above positive electrode was cut into a positive electrode sheet of 44 × 23mm in size, the copper foil coated with lithium metal was cut into a negative electrode sheet of 45 × 24mm in size, a pouch battery was prepared by a lamination method using the prepared positive and negative electrodes and a separator composed of three layers of polypropylene/polyethylene/polypropylene (PP/PE/PP), and then the prepared electrolyte was injected into a battery pack to complete the preparation of a lithium battery.

The graphs of the cycle performance test results of the batteries of example 23, example 30, example 36, example 40 and example 43 are shown in fig. 1, fig. 2, fig. 3, fig. 4 and fig. 5, respectively, and the graph of the cycle performance test result of the battery of comparative example 1 is shown in fig. 6. According to the test results, the star-shaped ether compound is added into the ether-based or carbonate-based electrolyte in equal amount, so that the cycle performance and capacity exertion performance of the lithium battery are better, and the cycle stability is improved. Compared with the application of the carbonate-based electrolyte (comparative example 1) of the traditional lithium ion battery in the lithium battery, the star-shaped ether compound added into the ether-based or fluorine-ether-based electrolyte can obviously improve the cycle performance and capacity exertion of the lithium battery.

Coulomb efficiency:

the preparation method of the button cell comprises the following steps of cutting a 500-micron lithium sheet into a 16 pi-sized wafer, cutting a copper foil into a 17 pi-sized wafer, and cutting a three-layer diaphragm composed of polypropylene/polyethylene/polypropylene (PP/PE/PP) into a 19 pi-sized wafer, wherein the preparation method of the button cell comprises the following steps: and placing the diaphragm between the anode and the cathode, filling the prepared electrolyte system between the anode and the cathode, packaging and compacting, and assembling into the CR2032 type button battery.

The button cells prepared above were tested for electrochemical properties using a blue cell battery (test results are shown in tables 1 and 2). Discharging is carried out for 2 hours by using a current density (calculated according to the area of the negative electrode) of 2mA/ce, then charging is carried out to 1V by using a current density (calculated according to the area of the negative electrode) of 2mA/ce, then discharging is carried out for 2 hours by using a current density (calculated according to the area of the negative electrode) of 2mA/ce, charging and discharging cycles are respectively carried out for ten weeks by using a current density (calculated according to the area of the negative electrode) of 2mA/ce after certain lithium is deposited on the surface of the copper foil, the battery is charged to 1V by using a current density (calculated according to the area of the negative electrode) of 2mA/ce after the cycles are finished, and the coulomb efficiency of the electrolyte to lithium metal is calculated according to the capacity. The results of coulombic efficiency tests for the cells of example 28, example 36 and example 37 are shown in fig. 7, fig. 8 and fig. 9, respectively. According to the test results, the addition of the star-shaped ether compound in the electrolyte based on ether or fluorine ether improves the coulomb efficiency of the electrolyte provided by the application to lithium.

In the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

While embodiments of the present application have been shown and described above, it will be understood that the above embodiments are exemplary and should not be construed as limiting the present application and that changes, modifications, substitutions and alterations in the above embodiments may be made by those of ordinary skill in the art within the scope of the present application.

Claims

1. A star ether compound is characterized by having the following structural formula:

wherein, X ₁ 、X ₂ 、X ₃ Each independently is- (CH) ₂ ) _a -；

R ₄ Is H or- (CH) ₂ ) _b -O-R ₅ ；

R ₁ 、R ₂ 、R ₃ And R ₅ Each independently selected from substituted or unsubstituted alkyl, substituted or unsubstitutedUnsubstituted haloalkyl, substituted or unsubstituted phenyl, substituted or unsubstituted halophenyl, substituted or unsubstituted benzyl, and substituted or unsubstituted halobenzyl;

wherein R is ₁ 、R ₂ 、R ₃ And R ₅ Contains a halogen including 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.

2. The star ether compound according to claim 1, wherein,

R ₁ 、R ₂ 、R ₃ and R ₅ 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;

c substituted as described above _1-6 Alkyl, substituted C _1-6 The substituents in haloalkyl, substituted phenyl, substituted halophenyl, substituted benzyl and substituted halobenzyl are each independently selected from C _1-6 Alkyl radical, C _1-6 Haloalkyl, C _1-6 Alkoxy radical, C _1-6 Haloalkoxy, C _1-6 Alkoxy-substituted C _1-6 Alkoxy radical, C _1-6 Alkoxy-substituted C _1-6 Haloalkoxy, C _1-6 Haloalkoxy substituted C _1-6 Alkoxy radical, C _1-6 Haloalkoxy substituted C _1-6 Haloalkoxy, C _1-6 Acyl radical, C _1-6 Cyanoalkoxy and cyano;

a is an integer of 0 to 6, and b is an integer of 0 to 6.

3. The star ether compound according to claim 1, wherein the halogen is fluorine.

4. The star ether compound according to claim 1, wherein R is R ₁ 、R ₂ 、R ₃ And R ₅ Each independently selected from C _1-6 Fluoroalkyl, C _1-4 Alkoxy-substituted C _1-4 Alkyl radical, C _1-4 Fluoroalkoxy-substituted C _1-4 Alkyl radical, C _1-4 Fluoroalkoxy-substituted C _1-4 Fluoroalkyl, C _1-4 Cyanoalkoxy-substituted C _1-4 Alkyl radical, C _1-4 Cyanoalkoxy-substituted C _1-4 Fluoroalkyl, fluorophenyl, C _1-4 Fluoroalkyl-substituted phenyl, fluorobenzyl, C _1-4 Fluoroalkyl substituted benzyl, first substituent substituted C _1-4 Alkyl and C substituted by a first substituent _1-4 A fluoroalkyl group; wherein the first substituent is C _1-4 Fluoroalkoxy-substituted C _1-4 Alkoxy radical, C _1-4 Fluoroalkoxy-substituted C _1-4 Fluoroalkoxy radical, C _1-4 Alkoxy-substituted C _1-4 Fluoroalkoxy and C _1-4 Alkoxy-substituted C _1-4 An alkoxy group;

a is an integer of 0 to 2, and b is an integer of 0 to 2.

5. The star ether compound according to claim 1, wherein R is R ₁ 、R ₂ 、R ₃ And R ₅ Each independently selected from the group consisting of:

6. the star ether compound according to claim 1, wherein at least one of the following conditions is satisfied:

R ₁ 、R ₂ and R ₃ All containing the halogen;

R ₁ 、R ₂ 、R ₃ and R ₅ All containing the halogen;

R ₁ 、R ₂ and R ₃ Are the same group; and

R ₁ 、R ₂ 、R ₃ and R ₅ Are the same group.

7. The star ether compound according to any one of claims 1 to 6, wherein,

X ₁ 、X ₂ 、X ₃ each independently is- (CH) ₂ ) _a -, and R ₄ Is H, wherein a is 0, 1 or 2; or alternatively

X ₁ 、X ₂ 、X ₃ Each independently is- (CH) ₂ ) _a -, and R ₄ Is- (CH) ₂ ) _b -O-R ₅ Wherein a is 1 or 2, b is 0, 1 or 2.

8. The star ether compound according to claim 1, comprising at least one of:

9. an electrolyte, comprising:

a lithium salt;

an organic solvent; and

the star ether compound according to any one of claims 1 to 8.

10. The electrolyte according to claim 9, wherein the molar ratio of the lithium salt, the organic solvent, and the star-shaped ether compound is 1 to 1.5.

11. The electrolyte of claim 9, wherein at least one of the following conditions is satisfied:

the lithium salt is selected from at least one of lithium phosphate, lithium borate, lithium boron cluster compound, lithium imide salt, lithium aluminate, lithium heterocyclic anion salt, lithium halide salt, lithium sulfonate and derivatives thereof;

the organic solvent comprises 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 comprises at least one of linear carbonate, cyclic carbonate and phosphate.

12. The electrolyte of claim 11, wherein at least one of the following conditions is satisfied:

the lithium salt is selected from at least one of lithium trifluoromethanesulfonate, lithium bistrifluoromethylsulfonyl imide, lithium difluorosulfonyl imide, lithium hexafluorophosphate, lithium hexafluoroarsenate, lithium difluorophosphate, lithium tetrafluoroborate, lithium difluorooxalato borate, lithium dioxaoxalato borate and lithium perchlorate;

the ether compound comprises cyclic ether and linear ether, and the volume ratio of the linear ether to the cyclic ether is 1-5:5-9;

the cyclic ether comprises at least one of 1, 3-dioxolane, 1, 4-dioxane, tetrahydrofuran, tetrahydropyran, and propylene oxide;

the linear ether comprises 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, tertiary butyl methyl ether, tertiary butyl ethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether and dipropylene glycol dimethyl 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, methyl ethyl 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-trifluoroethyl) methylphosphonate, trimethyl phosphate, triethyl phosphate, tripropyl phosphate and ethyl methyl phenyl phosphate.

13. The electrolyte of claim 9, wherein 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, gamma-butyrolactone, gamma-valerolactone, gamma-caprolactone, delta-valerolactone and epsilon-caprolactone;

the nitrile compound comprises at least one of acetonitrile, propionitrile, butyronitrile, valeronitrile, hexanenitrile, heptanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorobenzonitrile and 4-fluorobenzonitrile.

14. A lithium battery, comprising:

a positive electrode;

a negative electrode;

a separator between the positive electrode and the negative electrode;

the electrolytic solution according to any one of claims 9 to 13, wherein at least a part of the positive electrode, the negative electrode, and the separator is immersed in the electrolytic solution.