Nonaqueous electrolyte, secondary battery and electrical device

Abstract

The present application provides a non-aqueous electrolyte, a secondary battery, and an electric device. The non-aqueous electrolyte contains an additive, and the additive contains a cyclic sulfate ester compound having a structure represented by general formula (I), in which R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently any one selected from a group having a structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and n1, n2, and n3 are each independently any integer from 0 to 2.

Description

[Technical Field]

[0001] The present application relates to the field of battery technology, and in particular to non-aqueous electrolytes, secondary batteries, and electrical devices. [Background technology]

[0002] In recent years, with the development of lithium ion secondary battery technology, lithium ion secondary batteries have been widely applied to energy storage power supply systems such as hydroelectric power plants, thermal power plants, wind power plants, and solar power plants, as well as many fields such as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, etc. Due to the significant development of lithium ion secondary batteries, higher requirements are being placed on their fast charging performance, cycle performance, safety performance, etc.

[0003] Among battery performance goals, extending the lifespan of lithium secondary batteries, especially those used in automobiles, is a key requirement. Continuous reduction of the electrolyte at the anode during charging is known to be a cause of battery life degradation. To overcome this problem, researchers have attempted to add various compounds to the electrolyte to form a passivation layer, also known as an SEI film, on the anode surface. Because the SEI film is a good conductor of lithium ions and a poor conductor of electrons, it suppresses the continuation of the lithium consumption reaction and protects the electrode. Research has revealed that the formation of a solid electrolyte phase boundary film (SEI), which has excellent properties such as uniformity, density, stability, low impedance, and good adhesion, is advantageous for improving the electrochemical performance of batteries. Summary of the Invention

[0004] The present application provides a non-aqueous electrolyte, a secondary battery, and an electrical device for improving the cycle performance of the secondary battery.

[0005] A first aspect of the present application provides a non-aqueous electrolyte solution containing an additive, the additive containing a cyclic sulfate ester compound having a structure represented by general formula (I), [ka] Among them, R 1 , R 2 , R 3 and R 4 are each independently any one selected from a group having a structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and n1 and n2 are each independently any integer of 0 to 2, The general formula (II) is [ka] and R 5 and R 6 are each independently any one selected from a group having a structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and n3 is an integer of 0 to 2, R 1 and R 2 is not a hydrogen atom and R 3 and R 4 is not a hydrogen atom at the same time, Or R 1 , R 2 , R 3 , R 4 , R 5 and R 6 satisfies the following conditions: R 1 and R 2 is simultaneously a hydrogen atom and R 3 and R 4one of which is a hydrogen atom and the other is any one of a group having a structure represented by general formula (II), a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and in the group having a structure represented by general formula (II), R 5 and R 6 is not a hydrogen atom at the same time, Or R 1 , R 2 , R 3 , R 4 , R 5 and R 6 satisfies the following conditions: R 3 and R 4 is simultaneously a hydrogen atom and R 1 and R 2 one of which is a hydrogen atom and the other is any one selected from a group having a structure represented by general formula (II), a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and in the group having a structure represented by general formula (II), R 5 and R 6 is not a hydrogen atom at the same time.

[0006] When the cyclic sulfate ester compound having general formula (I) is used as an additive in a non-aqueous electrolyte, a more stable inorganic-organic hybrid SEI film with higher electron blocking capability is formed on the negative electrode side during the initial charge process of a secondary battery. This SEI film can block electrons and prevent the continuous decomposition of the electrolyte at the negative electrode, thereby providing low resistance to the negative electrode strip and significantly improving the cycle performance of the battery core, as well as significantly improving the battery life.

[0007] In any embodiment of the first aspect, the cyclic sulfate ester compound has a structure represented by general formula (I-1): [ka] R 1 , R 2 , R 3 and R 4 are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group; General formula (II-1) is [ka] and R 5 and R 6 are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group.

[0008] Since all of the cyclic sulfate rings in the general formula (I-1) are five-membered rings, a denser SEI film can be formed. Compared to six-membered rings, they have a higher ring tension, making film formation at the positive and negative electrodes easier. However, six-membered rings have a relatively small ring tension, are relatively stable, and film formation at the negative electrode is relatively slow. This results in a relatively low efficiency in generating an SEI film that blocks electrons, which impacts the effectiveness of the SEI film.

[0009] In any embodiment of the first aspect, optionally, R 1 , R 2 , R 3 , R 4 , R 5 and R 6are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C2-C3 alkenyl group, a C1-C3 ester group, a cyano group, and a sulfonic acid group.

[0010] In any embodiment of the first aspect, optionally, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, and a C1-C3 haloalkyl group.

[0011] In any embodiment of the first aspect, optionally, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, an F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, a propyl group, and an isopropyl group. In any embodiment of the first aspect, optionally, the group of the structure represented by general formula (II-1) is [ka] wherein X is an F atom, a Cl atom, or a Br atom.

[0012] In any embodiment of the first aspect, optionally, R 1 , R 2 , R 3 and R 4 are each independently [ka] , a hydrogen atom, an F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, and a propyl group, and X is an F atom.

[0013] In any embodiment of the first aspect, optionally, R 1 , R 2 , R 3 and R 4 are each independently [ka] , any one selected from a hydrogen atom, a methyl group, and an ethyl group, and X is an F atom.

[0014] In any embodiment of the first aspect, the cyclic sulfate ester compound is [ka] The compound is any one or more selected from the following compounds:

[0015] The above-mentioned method for producing the cyclic sulfate ester compound is simpler, more easily spread and implemented industrially, and the effect of improving the cycle performance of the secondary battery is more stable.

[0016] In any embodiment of the first aspect, the mass content of the cyclic sulfate ester compound in the nonaqueous electrolyte solution is 0.001% to 20%, for example, 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, alternatively 0.1% to 10%, and further alternatively 0.1% to 5%. The use of the cyclic sulfate ester compound allows for the efficient formation of an organic-inorganic hybrid SEI film that is more stable and has higher electron blocking capability, thereby effectively improving not only the cycle performance of the secondary battery but also the output power of the secondary battery.

[0017] In any embodiment of the first aspect, the nonaqueous electrolyte further comprises an electrolyte, optionally including an alkali metal salt-based electrolyte, optionally including a lithium salt or a sodium salt, optionally including one or more lithium salts selected from the group consisting of lithium hexafluorophosphate (LiPF), lithium perchlorate (LiClO), lithium hexafluoroarsenate (LiAsF), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and optionally including one or more sodium salts selected from the group consisting of sodium hexafluorophosphate, sodium difluoro(oxalato)borate, sodium perchlorate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethanesulfonyl)imide, and sodium trifluoromethanesulfonate. Each of the lithium salts may be used alone or in combination.

[0018] In any embodiment of the first aspect, the non-aqueous electrolyte further comprises a non-aqueous solvent, the non-aqueous solvent comprising one or more selected from the group consisting of cyclic carbonates, chain carbonates, nitrile solvents, ketone solvents, and sulfone solvents. Optionally, the non-aqueous solvent comprises one or more selected from the group consisting of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, diethyl sulfone, tetrahydrofuran, ethylene glycol dimethyl ether, dioxolane, acetone, acetonitrile, and butyronitrile. The non-aqueous solvents may be used alone or in combination of two or more.

[0019] In any embodiment of the first aspect, the additive further comprises one or more sultone compounds, thereby further improving the cycle performance of the battery. A second aspect of the present application provides a secondary battery comprising a positive electrode piece, an electrolyte, a separator film, and a negative electrode piece, wherein the electrolyte is any one of the non-aqueous electrolyte solutions described above. A secondary battery comprising the non-aqueous electrolyte solution of the present application exhibits significant improvements in output power and lifespan.

[0020] A third aspect of the present application provides an electric device including a secondary battery, the secondary battery including any one of the above secondary batteries. An electric device including the secondary battery according to the present application has a longer service life. [Brief explanation of the drawings]

[0021] In order to more clearly explain the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings used in the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can further obtain other drawings according to the drawings without any creative work. [Figure 1] 1 is a schematic diagram of a secondary battery according to an embodiment of the present application. [Figure 2] FIG. 2 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 1. [Figure 3] 1 is a schematic diagram of a battery module according to an embodiment of the present application; [Figure 4] 1 is a schematic diagram of a battery pack according to an embodiment of the present application; [Figure 5] FIG. 5 is an exploded view of the battery pack shown in FIG. 4 according to the embodiment of the present application. [Figure 6] 1 is a schematic diagram of an electrical device that uses a secondary battery as a power source according to an embodiment of the present application.

[0022] In the drawings, the drawings are not drawn to scale. Symbols: 1. Battery pack 2. Upper case 3. Lower case 4. Battery module 5, secondary battery 51. Casing 52, electrode assembly 53, top cover assembly. DETAILED DESCRIPTION OF THE INVENTION

[0023] The following detailed description of the embodiments of the present application will be given in conjunction with the drawings and examples. The detailed description of the embodiments and the drawings below are used to exemplify the principles of the present application, but are not intended to limit the scope of the present application, i.e., the present application is not limited to the described examples.

[0024] Hereinafter, with reference to the drawings as appropriate, embodiments specifically disclosing the nonaqueous electrolyte, secondary battery, and electrical device according to the present application will be described in detail. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or repeated description of substantially identical configurations may be omitted. This is to avoid unnecessarily lengthening the following description and to facilitate understanding by those skilled in the art. Furthermore, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the scope of the claims.

[0025] The "ranges" disclosed herein are defined by lower and upper limits, and a given range is defined by selecting one lower limit and one upper limit, with the selected lower and upper limits defining the boundaries of that particular range. Such defined ranges may be inclusive or exclusive of both endpoints and may be arbitrarily combined; i.e., any lower limit can be combined with any upper limit to form a single range. For example, if ranges of 60 to 120 and 80 to 110 are recited for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if the recited minimum range values ​​are 1 and 2, and the recited maximum range values ​​are 3, 4, and 5, then the ranges 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 are all contemplated. Unless otherwise specified, the numerical range "a to b" herein represents a shorthand notation for any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0 to 5" indicates that all real numbers between "0 and 5" have already been listed in this specification, and "0 to 5" is simply an abbreviation for a combination of those numerical values. Note that when a parameter is described as an integer ≧2, this is equivalent to disclosing that the parameter is an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0026] Unless otherwise specified, all embodiments and optional embodiments in the present application can be combined with each other to form a new technical solution.

[0027] Unless otherwise specified, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0028] Unless otherwise specified, all steps in the present application may be performed sequentially or randomly, but are preferably performed sequentially. For example, when the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, when the method described above may further include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or may include steps (a), (c), and (b), or may include steps (c), (a), and (b), etc.

[0029] Unless otherwise specified, the terms "comprise" and "comprises" used in this application may be open or closed. For example, the terms "comprise" and "comprises" may further include or include other components not listed, or may include or include only the listed components.

[0030] Unless otherwise stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, any of the following conditions satisfy the condition "A or B": A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), or both A and B are true (or exist).

[0031] [Secondary battery]

[0032] Secondary batteries, also called rechargeable batteries or storage batteries, refer to batteries that can be continuously used by activating the active materials by charging them after discharging them.

[0033] A typical secondary battery comprises a positive electrode, a negative electrode, a separator film, and an electrolyte. During the charge and discharge process, active ions (e.g., lithium ions or sodium ions) are repeatedly inserted and removed between the positive and negative electrode pieces. The separator film is located between the positive and negative electrode pieces and primarily serves to prevent short circuits between the positive and negative electrodes while allowing the active ions to pass through. The electrolyte is located between the positive and negative electrode pieces and primarily serves to conduct the active ions.

[0034] [Nonaqueous electrolyte] One embodiment of the present application provides a non-aqueous electrolyte solution containing an additive, the additive including a cyclic sulfate ester compound having a structure represented by general formula (I), [ka] Among them, R 1 , R 2 , R 3 and R 4 are each independently any one selected from a group having a structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and n1 and n2 are each independently any integer of 0 to 2, The general formula (II) is [ka] and R 5 and R 6 are each independently any one selected from a group having a structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and n3 is an integer of 0 to 2, R 1 and R 2 is not a hydrogen atom and R 3 and R 4is not a hydrogen atom at the same time, Or R 1 , R 2 , R 3 , R 4 , R 5 and R 6 satisfies the following conditions: R 1 and R 2 is simultaneously a hydrogen atom and R 3 and R 4 one of which is a hydrogen atom and the other is any one of a group having a structure represented by general formula (II), a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and in the group having a structure represented by general formula (II), R 5 and R 6 is not a hydrogen atom at the same time, Or R 1 , R 2 , R 3 , R 4 , R 5 and R 6 satisfies the following conditions: R 3 and R 4 is simultaneously a hydrogen atom and R 1 and R 2 one of which is a hydrogen atom and the other is any one selected from a group having a structure represented by general formula (II), a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and in the group having a structure represented by general formula (II), R 5 and R 6 At the same time, it is not a hydrogen atom, but a non-aqueous electrolyte.

[0035] When the cyclic sulfate ester compound having general formula (I) is used as an additive in a non-aqueous electrolyte, a more stable inorganic-organic hybrid SEI film with higher electron blocking capability is formed on the negative electrode side during the initial charge process of a secondary battery. This SEI film can block electrons and prevent the continuous decomposition of the electrolyte at the negative electrode, thereby providing low resistance to the negative electrode strip and significantly improving the cycle performance of the battery core, as well as significantly improving the battery life.

[0036] Although the mechanism by which the cyclic sulfate ester compound exhibits the above-mentioned effects is not yet clear, the applicant speculates as follows: Based on the fact that the cyclic sulfate ester compound has a skeleton connected by two cyclic sulfate ester rings, the introduction of a substituent such as an alkyl group can form an SEI film with longer organic chains at the anode, which can accommodate the volume changes that occur at the anode during cycling and prevent the SEI film from being destroyed; the introduction of a substituent containing F and N can participate in the film formation at the anode, forming an SEI film richer in more inorganic components such as LiF and LiN, thereby improving the mechanical strength of the SEI film and further improving the stability of the SEI film at the anode, thereby achieving the goal of improving the cycle performance of the battery.

[0037] The alkyl group may be a straight chain alkyl group, a branched chain alkyl group, or a cycloalkyl group, including, but not limited to, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a cyclopropyl group, a cyclobutyl group, etc. The alkyl group in the haloalkyl group may be a straight chain alkyl group, a branched chain alkyl group, or a cycloalkyl group, including, but not limited to, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a cyclopropyl group, a cyclobutyl group, etc. The halogen atom may be a fluorine atom, a base atom, or a bromine atom, and the halogen atom in the alkyl group may be, but not limited to, a fluorine atom, a bromide atom, or a bromine atom. The alkoxy group may be substituted with any one or more hydrogen atoms, and the alkoxy group includes, but is not limited to, a cyclopropyl group, an oxetanyl group, etc. The halogen atom in the haloalkoxy group may be a fluorine atom, an alkyl atom, or a bromine atom, and the halogen atom may replace any one or more hydrogen atoms in the alkoxy group. The alkenyl group includes, but is not limited to, -CH=CH2, -CH=CH2CH3, -CH2CH=CH2, and -CH2CH=CH2CH3. The ester group includes, but is not limited to, a methyl formate group, an ethyl formate group, an ethyl acetate group, a methyl propionate group, an ethyl propionate group, a propyl propionate group, etc.

[0038] In some embodiments of the present application, the cyclic sulfate ester compound has a structure represented by general formula (I-1): [ka] R 1 , R 2 , R 3 and R 4 are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group; General formula (II-1) is [ka] and R 5 and R 6 are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group.

[0039] Since all of the cyclic sulfate rings in the general formula (I-1) are five-membered rings, a denser SEI film can be formed. Compared to six-membered rings, they have a higher ring tension, making film formation at the positive and negative electrodes easier. However, six-membered rings have a relatively small ring tension, are relatively stable, and film formation at the negative electrode is relatively slow. This results in a relatively low efficiency in generating an SEI film that blocks electrons, which impacts the effectiveness of the SEI film.

[0040] In some embodiments of the present application, optionally, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, a C1-C3 haloalkyl group, a C1-C3 alkoxy group, a C1-C3 haloalkoxy group, a C2-C3 alkenyl group, a C1-C3 ester group, a cyano group, and a sulfonic acid group.

[0041] In some embodiments of the present application, optionally, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1-C3 alkyl group, and a C1-C3 haloalkyl group.

[0042] In some embodiments of the present application, optionally, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, an F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, a propyl group, and an isopropyl group.

[0043] In some embodiments of the present application, optionally, the group of the structure represented by the general formula (II-1) is [ka] wherein X is an F atom, a Cl atom, or a Br atom.

[0044] In some embodiments of the present application, optionally, R 1 , R 2 , R 3 and R 4 are each independently [ka] , a hydrogen atom, an F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, a propyl group, and an isopropyl group, and X is an F atom.

[0045] In some embodiments of the present application, optionally, R 1 , R 2 , R 3 and R 4 are each independently [ka] , any one selected from a hydrogen atom, a methyl group, and an ethyl group, and X is an F atom.

[0046] In some embodiments of the present application, the cyclic sulfate ester compound is [ka] The compound is any one or more selected from the following compounds:

[0047] Some of the methods for producing the above cyclic sulfate ester compounds are simpler, more easily widespread and industrially implemented, and have a more stable effect of improving the life of secondary batteries.

[0048] The dosage of the cyclic sulfate ester compound in each of the above embodiments of the present application may refer to the dosage of a typical cyclic sulfate ester compound in a typical non-aqueous electrolyte. In some embodiments, the mass content of the cyclic sulfate ester compound in the non-aqueous electrolyte is 0.001% to 20%, for example, 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, or alternatively 0.1% to 10%, or more alternatively 0.1% to 5%. The use of the cyclic sulfate ester compound effectively forms an organic-inorganic hybrid SEI film with a more stable and stronger electron blocking capability, which can effectively improve not only the cycle performance of the secondary battery but also the output power of the secondary battery. The above mass content limit prevents the SEI film from functioning satisfactorily due to an excessively low content of the cyclic sulfate ester compound, and also prevents the electrolyte from becoming too viscous and the SEI film formed on the negative electrode becoming too thick due to an excessively high content of the cyclic sulfate ester compound, thereby reducing the conductivity of the electrolyte and further reducing the effects of improving cycle performance and charging capacity.

[0049] In some embodiments, the non-aqueous electrolyte solution further comprises an electrolyte, and any electrolyte generally usable for non-aqueous electrolyte solutions may be used in the non-aqueous electrolyte solution of the present application. Those skilled in the art can select an electrolyte based on the battery system in which the non-aqueous electrolyte solution is to be used, for example, in the same way as selecting a typical electrolyte for a lithium-ion secondary battery or a sodium-ion secondary battery. In some embodiments, the electrolyte in the nonaqueous electrolyte solution includes an alkali metal salt-based electrolyte, and optionally includes a lithium salt or a sodium salt. The lithium salt may include one or more selected from the group consisting of lithium hexafluorophosphate (LiPF), lithium perchlorate (LiClO), lithium hexafluoroarsenate (LiAsF), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The sodium salt may include one or more selected from the group consisting of sodium hexafluorophosphate, sodium difluoro(oxalato)borate, sodium perchlorate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethanesulfonyl)imide, and sodium trifluoromethanesulfonate. Each of the lithium salts or sodium salts may be used alone or in combination.

[0050] The content of the electrolyte in the non-aqueous electrolyte can refer to the content of the electrolyte in a typical non-aqueous electrolyte. In some embodiments, the content of the electrolyte in the non-aqueous electrolyte is 0.1 to 5 mol / L, for example, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 4 mol / L, or 5 mol / L, optionally 0.5 to 1.5 mol / L, and further optionally 0.7 to 1.2 mol / L.

[0051] The nonaqueous solvent of the present application can be selected from nonaqueous solvents commonly used for secondary batteries, and in some embodiments, the nonaqueous solvent includes one or more selected from the group consisting of cyclic carbonates, chain carbonates, nitrile solvents, ketone solvents, and sulfone solvents. Optionally, the nonaqueous solvent includes one or more selected from the group consisting of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, diethyl sulfone, tetrahydrofuran, ethylene glycol dimethyl ether, dioxolane, acetone, acetonitrile, and butyronitrile. The nonaqueous solvents may be used alone or in combination of two or more. For example, a mixed solvent of a cyclic carbonate ester and a chain carbonate ester may be used to improve the load characteristics and low-temperature characteristics of the secondary battery. When the nonaqueous electrolyte solution according to the present invention is used in a solid-state battery, a solid solvent such as dimethyl sulfone may be used.

[0052] In addition to the above additives, the additives may include additives for negative electrode film formation, additives for positive electrode film formation, and additives capable of improving certain performance of the battery, such as additives for improving the overcharge performance of the battery, additives for improving the high-temperature or low-temperature performance of the battery, etc. In some embodiments, the additives further include one or more sultone compounds. Adding a sultone compound further improves the cycle performance of the secondary battery.

[0053] [Method for producing a cyclic sulfate compound having a structure represented by general formula (I)] The method for producing the cyclic sulfate ester compound having the structure represented by general formula (I) according to the present application is based on the following synthesis route: [ka] The reaction temperature of the first step is controlled at 30-60°C, and the reaction temperature of the second step is controlled at 10-30°C. The second step is catalyzed by a catalyst such as ruthenium trichloride trihydrate, and the oxidizing agent may be sodium hypochlorite, ozone, etc.

[0054] [Positive electrode piece] A positive electrode piece generally includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, the positive electrode film layer including a positive electrode active material.

[0055] As an example, the positive electrode current collector has two surfaces that face each other in the thickness direction of the positive electrode current collector, and the positive electrode film layer is disposed on one or both of the two facing surfaces of the positive electrode current collector.

[0056] In some embodiments, the positive electrode current collector can be a metal foil piece or a composite current collector. For example, the metal foil piece can be aluminum foil. The composite current collector can include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material base layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymeric material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0057] In some embodiments, the positive electrode active material can be a positive electrode active material used in batteries known in the art. As an example, a positive electrode active material used in a lithium-ion secondary battery may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and modified compounds thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials in batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include lithium cobalt oxide (e.g., LiCoO), lithium nickel oxide (e.g., LiNiO), lithium manganese oxide (e.g., LiMnO, LiMnO), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (e.g., LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 Examples of the lithium-containing phosphate having an olivine structure may include, but are not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which may be abbreviated as LFP)), a composite of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite of lithium manganese iron phosphate and carbon.

[0058] As an example, the positive electrode active material used in a sodium ion secondary battery may contain at least one of a sodium transition metal oxide, a polyanion-based compound, and a Prussian blue-based compound. However, the present application is not limited to these materials, and other conventional materials that can be used as the positive electrode active material of the battery may also be used. These positive electrode active materials may be used alone as only one kind, or may be used in combination of two or more kinds. Among them, in the sodium transition metal oxide, the transition metal contains at least one selected from the group consisting of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce. The sodium transition metal oxide is, for example, NaxMO2, where M contains one or more selected from the group consisting of Ti, V, Mn, Co, Ni, Fe, Cr, and Cu, and 0 < x ≦ 1. The polyanion-based compound is a compound having sodium ions, transition metal ions, and a tetrahedral (YO4) n- anion unit, and the transition metal contains at least one selected from the group consisting of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce, Y contains at least one selected from the group consisting of P, S, and Si, and n represents the valence state of (YO4) n- The polyanion-based compound may be one kind of a compound having sodium ions, transition metal ions, a tetrahedral (YO4) n- anion unit, and a halogen anion, the transition metal contains at least one selected from the group consisting of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce, Y contains at least one selected from the group consisting of P, S, and Si, and n represents the valence state of (YO4) n- and the halogen contains at least one selected from the group consisting of F, Cl, and Br. The polyanion-based compound may be a compound having sodium ions, a tetrahedral (YO4) n- anion unit, a polyhedron unit (ZO y ) m+ and a selective halogen anion, Y contains at least one selected from the group consisting of P, S, and Si, and n represents the valence state of (YO4) n-Z represents a transition metal and includes at least one selected from the group consisting of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce, and m represents a valence state of (ZO y ) m+ The halogen includes at least one selected from the group consisting of F, Cl, and Br. The polyanionic compounds include NaFePO4, Na3V2(PO4)3, NaM'PO4F (wherein M' includes one or more selected from the group consisting of V, Fe, Mn, and Ni), and Na3(VO y )2(PO4)2F 3-2y (0≦y≦1). The Prussian blue-based compound contains at least one selected from the group consisting of sodium ions, transition metal ions, and cyanide ions (CN - The transition metal may include at least one selected from the group consisting of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce. The Prussian blue compound may be, for example, a compound having Na a Me b Me' c (CN)6, wherein Me and Me' each independently comprise at least one selected from the group consisting of Ni, Cu, Fe, Mn, Co, and Zn; <a≦2、0<b<1、0<c<1である。

[0059] In some embodiments, the positive electrode film layer may further optionally include an adhesive. For example, the adhesive may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0060] In some embodiments, the positive electrode film layer may further optionally include a conductive agent, for example, superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0061] In some embodiments, the positive electrode pieces can be manufactured as follows: the components for manufacturing the positive electrode pieces, such as the positive electrode active material, the conductive agent, the adhesive, and any other components, are dispersed in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry, and the positive electrode slurry is applied to a positive electrode current collector. After undergoing processes such as drying and cold pressing, the positive electrode pieces can be obtained.

[0062] [Negative electrode piece] The negative electrode piece includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, the negative electrode film layer including a negative electrode active material.

[0063] As an example, the negative electrode current collector has two surfaces that face each other in the thickness direction thereof, and the negative electrode film layer is disposed on one or both of the two facing surfaces of the negative electrode current collector.

[0064] In some embodiments, the negative electrode current collector may be a metal foil strip or a composite current collector. For example, the metal foil strip may be copper foil. The composite current collector may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material substrate. The composite current collector may be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) on a polymeric material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), or polyethylene (PE)).

[0065] In some embodiments, the negative electrode active material can be any negative electrode active material known in the art for batteries. For example, the negative electrode active material may include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin-oxygen compounds, and tin alloys. However, the present application is not limited to these materials, and other conventional materials usable as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination.

[0066] In some embodiments, the negative electrode film layer may further optionally include an adhesive. For example, the adhesive may be selected from at least one of styrene butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0067] In some embodiments, the negative electrode film layer may further optionally include a conductive agent, for example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0068] In some embodiments, the negative electrode film layer may further optionally contain other additives, such as a thickener (eg, sodium carboxymethylcellulose (CMC-Na)).

[0069] In some embodiments, the negative electrode pieces can be manufactured as follows: the above-mentioned components for manufacturing the negative electrode pieces, such as the negative electrode active material, the conductive agent, the adhesive, and any other components, are dispersed in a solvent (e.g., deionized water) to form a negative electrode slurry, and the negative electrode slurry is applied to a negative electrode current collector, and after processes such as drying and cold pressing, the negative electrode pieces can be obtained.

[0070] [Separator film] In some embodiments, the secondary battery further includes a separator film. The present application does not particularly limit the type of separator film, but any separator film having a known porous structure and good chemical and mechanical stability can be selected.

[0071] In some embodiments, the separator film may be made of at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator film may be a single-layer thin film or a multi-layer composite thin film, without any particular limitation. When the separator film is a multi-layer composite thin film, the materials of the layers may be the same or different, without any particular limitation.

[0072] In some embodiments, the positive electrode strips, negative electrode strips, and separator film can be fabricated into an electrode assembly by a winding or lamination process.

[0073] In some embodiments, the secondary battery may include an outer packaging that can be used to encapsulate the electrode assembly and electrolyte.

[0074] In some embodiments, the exterior packaging of the secondary battery may be a hard casing, such as a hard plastic casing, an aluminum case, a steel case, etc. The exterior packaging of the secondary battery may be a pouch, such as a bag-type pouch. The pouch may be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0075] The present application does not particularly limit the shape of the secondary battery, but it may be cylindrical, rectangular, or any other shape. For example, Fig. 1 shows a secondary battery 5 having a rectangular structure as an example.

[0076] In some embodiments, referring to FIG. 2 , the outer packaging may include a casing 51 and a cover plate 53. The casing 51 includes a base plate and a side plate connected to the base plate, which together form a surrounding accommodating chamber. The casing 51 has an opening communicating with the accommodating cavity, and the cover plate 53 can cover the opening and close the accommodating cavity. The positive electrode piece, the negative electrode piece, and the separator film can be formed into an electrode assembly 52 by a winding or lamination process. The electrode assembly 52 is sealed in the accommodating cavity. An electrolyte is impregnated into the electrode assembly 52. ​​The secondary battery 5 may include one or more electrode assemblies 52, which can be selected by those skilled in the art according to specific practical needs.

[0077] In some embodiments, the secondary batteries can be assembled into a battery module, and the number of secondary batteries included in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0078] 3 shows a battery module 4 as an example. Referring to FIG. 3, in the battery module 4, the plurality of secondary batteries 5 may be arranged in order along the length of the battery module 4. Of course, they may be arranged in any other manner. Furthermore, the plurality of secondary batteries 5 may be fixed by fastening members.

[0079] Optionally, the battery module 4 may further include an exterior case having an accommodating space, and the plurality of secondary batteries 5 are accommodated in the accommodating space.

[0080] In some embodiments, the battery modules can also be assembled into a battery pack, and the number of battery modules included in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0081] 4 and 5 show a battery pack 1 as an example. Referring to FIGS. 4 and 5, the battery pack 1 may include a battery box and a plurality of battery modules 4 installed in the battery box. The battery box includes an upper case 2 and a lower case 3, and the upper case 2 is attached to the lower case 3 as a cover, forming a sealed space for accommodating the battery modules 4. A plurality of battery modules 4 may be installed in the battery box as desired.

[0082] The present application also provides an electric device including at least one of the secondary battery, battery module, or battery pack provided by the present application. The secondary battery, battery module, or battery pack may be used as a power source for the electric device or as an energy storage unit for the electric device. The electric device includes, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships, satellites, energy storage systems, etc.

[0083] The electric device can be selected as a secondary battery, a battery module or a battery pack according to the needs of the use.

[0084] 6 shows an example of an electric device, such as a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the demand for high power and high energy density from secondary batteries, a battery pack or a battery module can be used.

[0085] [Example] The following examples are provided for illustrative purposes only and are not intended to limit the scope of the present application. Unless specific techniques or conditions are described in the examples, they are carried out in accordance with the techniques or conditions described in the technical literature or in accordance with the product instructions. Unless the manufacturer is specified, the reagents or equipment used are all commercially available, and information on other reagents or compounds is listed in Table 1. [Table 1]

[0086] Synthesis example 1: Compound 1 [ka] Synthesis of Step 1: Add 300g (2mol) of solid 1,6-dideoxygalactitol to a 2L three-neck flask and begin stirring. Add 523g (4.4mol) of thionyl chloride dropwise to the three-neck flask. Control the temperature at about 15℃ during the addition process. After the addition is complete, keep the temperature at 45℃ and react for 4 hours. A large amount of paste-like solid precipitates from the reaction solution. After cooling, add 1L of deionized water slowly dropwise and rapidly stir the reaction system to disperse it. Filter the solid and wash it repeatedly with deionized water until the pH becomes neutral. Dry the filter cake at 60℃ under reduced pressure to obtain the intermediate product.

[0087] Step 2: Add 184.2 g (0.8 mol) of intermediate product 1 to a 3 L three-neck flask, add 1000 mL of acetonitrile, and add 80 mg of ruthenium trichloride trihydrate catalyst. After purging the reaction system with nitrogen gas, the reaction system is cooled to 20°C and stirring begins. Within 1 hour, 2000 g of 20% aqueous sodium hypochlorite solution is added dropwise. The reaction temperature is controlled at 10-20°C. After the addition is complete, the mixture is stirred at 10-20°C for 10 minutes, and the solution is separated. The organic phase is quenched with an aqueous sodium sulfite solution so that the potassium iodide starch test paper does not turn blue. The solution is separated again, and the organic layer is concentrated. The acetonitrile crystallizes, yielding the above-mentioned compound 1 as a white powder solid. 1H-NMR, CD3CN, δ ppm 5.42-5.39 (m, 2H), 5.36-5.34 (m, 2H), 1.67-1.65 (d, 6H).

[0088] Synthesis example 2: Compound 2 [ka] Synthesis of Step 1: 356.5g (2mol) of solid 3,4,5,6-octanetetraol was added to a 2L three-necked flask and stirred. 523g (4.4mol) of thionyl chloride was added dropwise to the three-necked flask. The temperature was controlled at about 15°C during the addition process. After the addition was completed, the mixture was kept at 45°C and allowed to react for 4 hours. A large amount of paste-like solid precipitated from the reaction solution. After cooling, 1L of deionized water was slowly added dropwise. The reaction system was quickly stirred and dispersed. The solid obtained by filtration was slurried and washed repeatedly with deionized water until the pH became neutral. The filter cake was dried under reduced pressure at 60°C to obtain the intermediate product.

[0089] Step 2: Add 216.2 g (0.8 mol) of intermediate product 1 to a 3 L three-neck flask, add 1000 mL of acetonitrile, and add 80 mg of ruthenium trichloride trihydrate catalyst. After purging the reaction system with nitrogen gas, the reaction system is cooled to 20°C and stirring begins. Within 1 hour, 2000 g of 20% aqueous sodium hypochlorite solution is added dropwise, and the reaction temperature is controlled at 10-20°C. After the addition is complete, the mixture is stirred at 10-20°C for 10 minutes, and the solution is separated. The organic phase is quenched with aqueous sodium sulfite solution until the potassium iodide starch test paper does not turn blue. The solution is separated again, and the organic layer is concentrated. The acetonitrile crystallizes to obtain compound 2.

[0090] Synthesis example 3: Compound 3 [ka] Synthesis of Step 1: 328.4g (2mol) of solid 2,3,4,5-heptanetetraol was added to a 2L three-necked flask and stirred. 523g (4.4mol) of thionyl chloride was added dropwise to the three-necked flask. The temperature was controlled at about 15°C during the addition process. After the addition was completed, the mixture was kept at 45°C and allowed to react for 4 hours. A large amount of paste-like solid precipitated from the reaction solution. After cooling, 1L of deionized water was slowly added dropwise. The reaction system was quickly stirred and dispersed. The solid obtained by filtration was slurried and washed repeatedly with deionized water until the pH became neutral. The filter cake was dried under reduced pressure at 60°C to obtain the intermediate product.

[0091] Step 2: Add 205 g (0.8 mol) of intermediate product 1 to a 3 L three-neck flask, add 1000 mL of acetonitrile, and stir until the solid is completely dissolved. Add 80 mg of ruthenium trichloride trihydrate catalyst, and flush the reaction system with nitrogen gas. Then, cool the reaction system to 20 °C and begin stirring. Add 2000 g of 20% aqueous sodium hypochlorite solution dropwise within 1 h. Control the reaction temperature at 10-20 °C. After the addition is complete, stir at 10-20 °C for 10 min. Separate the solution. Quench the organic phase with aqueous sodium sulfite solution until the potassium iodide starch test paper turns blue. Separate the solution again. The organic layer was concentrated, and the acetonitrile crystallized to obtain compound 3 (163.1 g, 82.8% yield).

[0092] Synthesis example 4: Compound 4 [ka] Synthesis of Step 1: Add 392.4g (2mol) of solid 1,2,3,4,5,6-heptanol to a 2L three-neck flask and begin stirring. Add 784.5g (6.6mol) of thionyl chloride dropwise to the three-neck flask. Control the temperature at about 15℃ during the addition process. After the addition is complete, keep the temperature at 45℃ and react for 4 hours. A large amount of paste-like solid precipitates from the reaction solution. After cooling, add 1L of deionized water slowly dropwise. Stir the reaction system quickly to disperse it. Filter the solid and wash it repeatedly with deionized water until the pH becomes neutral. Dry the filter cake at 60℃ under reduced pressure to obtain the intermediate product.

[0093] Step 2: Add 140 g (0.4 mol) of intermediate product 1 to a 4 L three-neck flask, add 1000 mL of acetonitrile, and add 110 mg of ruthenium trichloride trihydrate catalyst. After purging the reaction system with nitrogen gas, the reaction system is cooled to 20°C and stirring begins. Within 1 hour, 1500 g of 20% aqueous sodium hypochlorite solution is added dropwise, and the reaction temperature is controlled at 10-20°C. After the addition is complete, the mixture is stirred at 10-20°C for 10 minutes, and the solution is separated. The organic phase is quenched with aqueous sodium sulfite solution until the potassium iodide starch test paper does not turn blue. The solution is separated again, and the organic layer is concentrated. The acetonitrile crystallizes to obtain compound 4.

[0094] Synthesis example 5: Compound 5 [ka] Synthesis of Step 1: Add 484g (2mol) of solid octitol into a 2L three-necked flask and begin stirring. Add 1046g (8.8mol) of thionyl chloride dropwise to the three-necked flask. Control the temperature at about 15℃ during the addition process. After the addition is complete, keep the temperature at 45℃ and react for 4 hours. A large amount of paste-like solid will precipitate from the reaction solution. After cooling, add 1L of deionized water slowly dropwise. Stir the reaction system quickly to disperse it. Filter the solid and wash it repeatedly with deionized water until the pH becomes neutral. Dry the filter cake at 60℃ under reduced pressure to obtain the intermediate product.

[0095] Step 2: Add 183.2 g (0.4 mol) of the intermediate product to a 4 L three-neck flask, add 1000 mL of acetonitrile, and add 150 mg of ruthenium trichloride trihydrate catalyst. After purging the reaction system with nitrogen gas, the reaction system is cooled to 20°C and stirring begins. Within 1 hour, 2000 g of 20% aqueous sodium hypochlorite solution is added dropwise, and the reaction temperature is controlled at 10-20°C. After the addition is complete, the mixture is stirred at 10-20°C for 10 minutes, and the solution is separated. The organic phase is quenched with aqueous sodium sulfite solution until the potassium iodide starch test paper does not turn blue. The solution is separated again, and the organic layer is concentrated. The acetonitrile crystallizes to obtain compound 5.

[0096] The compound was synthesized in accordance with Synthesis Example 1, except that the corresponding substrates in Table 2 were used in place of 1,6-dideoxygalactitol. [Table 2]

[0097] Example 1 Composition of the electrolyte: Compound 1 was used as an additive with a mass content of 2% in the electrolyte, lithium hexafluorophosphate LiPF6 was used as an electrolyte with a mass content of 10% in the electrolyte, and a mixture of EC+EMC (ethylene carbonate+ethyl methyl carbonate) with a volume ratio of 3:7 was used as a solvent.

[0098] Cathode piece manufacturing: The positive electrode active material, lithium iron phosphate (LiFePO4), the conductive agent, acetylene black, and the adhesive, polyvinylidene fluoride (PVDF), were dissolved in the solvent, N-methylpyrrolidone (NMP), in a weight ratio of 90:5:5, and the mixture was thoroughly stirred to obtain a positive electrode slurry. The positive electrode slurry was then uniformly applied to the positive electrode current collector, which was then dried, cold pressed, and cut to obtain positive electrode pieces.

[0099] Anode piece manufacturing: The negative electrode active material, graphite, the conductive agent, carbon black, the adhesive, styrene butadiene rubber (SBR), and the thickener, sodium carboxymethyl cellulose (CMC-Na), were dissolved in deionized water as a solvent in a weight ratio of 90:4:4:2 and mixed uniformly to produce a negative electrode slurry. The negative electrode slurry was then uniformly applied once or multiple times to copper foil, the negative electrode current collector, and the negative electrode pieces were obtained after drying, cold pressing, and cutting.

[0100] Separator Film: A conventional polypropylene film was used as the separator film.

[0101] Lithium-ion battery assembly: The positive electrode pieces, separator film, and negative electrode pieces were stacked in this order, with the separator film positioned between the positive electrode pieces and the negative electrode pieces to provide a gap between them, and then wound up to obtain an electrode assembly. The electrode assembly was then placed in a battery casing, dried, and then an electrolyte was injected. After further processes such as chemical formation and standing, a lithium-ion battery was manufactured.

[0102] Example 2 The same procedures as in Example 1 were carried out except that Compound 2 was used instead of Compound 1.

[0103] Example 3 The same procedures as in Example 1 were carried out except that Compound 3 was used instead of Compound 1.

[0104] Example 4 The same procedures as in Example 1 were carried out except that Compound 4 was used in place of Compound 1.

[0105] Example 5 The same procedures as in Example 1 were carried out except that Compound 5 was used in place of Compound 1.

[0106] Example 6 The same procedures as in Example 1 were carried out except that Compound 6 was used in place of Compound 1.

[0107] Example 7 The same procedures as in Example 1 were carried out except that Compound 7 was used instead of Compound 1.

[0108] Example 8 The procedure was the same as in Example 1, except that Compound 8 was used instead of Compound 1.

[0109] Example 9 The procedure was the same as in Example 1, except that Compound 9 was used instead of Compound 1.

[0110] Example 10 The same procedures as in Example 1 were carried out except that Compound 10 was used instead of Compound 1.

[0111] Example 11 The same procedures as in Example 1 were carried out except that Compound 11 was used instead of Compound 1.

[0112] Example 12 The same procedures as in Example 1 were carried out except that Compound 12 was used instead of Compound 1.

[0113] Example 13 The mass content of Compound 1 was adjusted to 0.005%, and the other conditions were the same as in Example 1.

[0114] Example 14 The mass content of Compound 1 was adjusted to 0.01%, and the other conditions were the same as in Example 1.

[0115] Example 15 The mass content of Compound 1 was adjusted to 0.05%, and the other conditions were the same as in Example 1.

[0116] Example 16 The mass content of Compound 1 was adjusted to 0.1%, and the other conditions were the same as in Example 1.

[0117] Example 17 The mass content of Compound 1 was adjusted to 1%, and the other conditions were the same as in Example 1.

[0118] Example 18 The mass content of Compound 1 was adjusted to 5%, and the other conditions were the same as in Example 1.

[0119] Example 19 The mass content of Compound 1 was adjusted to 10%, and the other conditions were the same as in Example 1.

[0120] Example 20 The mass content of Compound 1 was adjusted to 15%, and the other conditions were the same as in Example 1.

[0121] Example 21 The mass content of Compound 1 was adjusted to 20%, and the other conditions were the same as in Example 1.

[0122] Example 22 The mass content of Compound 1 was adjusted to 23%, and the other conditions were the same as in Example 1.

[0123] Example 23 Subsequently, 1,3-propane sultone (1,3-PS) was added to the electrolyte as a second additive, and its mass content in the electrolyte was 1%, and the other conditions were the same as in Example 1.

[0124] Example 24 The other conditions were the same as in Example 1, except that lithium hexafluorophosphate was replaced with lithium bis(fluorosulfonyl)imide (LiFSI), and its mass content in the electrolyte was adjusted to 15.4%.

[0125] Example 25 The other conditions were the same as in Example 1, except that lithium hexafluorophosphate was replaced with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and its mass content in the electrolyte was adjusted to 23.6%.

[0126] Example 26 Electrolyte: Sodium hexafluorophosphate (NaPF6) was used instead of lithium hexafluorophosphate, and its mass content in the electrolyte was adjusted to 13.8%, and the rest was the same as in Example 1.

[0127] Preparation of positive electrode pieces: The positive electrode active material NaFePO4, the conductive agent acetylene black, and the adhesive polyvinylidene fluoride (PVDF) were mixed homogeneously in a mass ratio of 80:10:10 in an N-methylpyrrolidone solvent system by thorough stirring. The mixture was then applied to an Al foil, dried, and cold pressed to obtain a negative electrode piece.

[0128] Preparation of negative electrode pieces: Hard carbon as the negative electrode active material, acetylene black as the conductive agent, and polyacrylic acid as the adhesive were thoroughly mixed in a deionized water solvent system in a mass ratio of 88:2:10, and then coated on copper foil, dried, and cold pressed to obtain positive electrode pieces.

[0129] The positive electrode pieces, negative electrode pieces, and polypropylene separator film were wound up to form a battery core, and then the battery core was incorporated into the outer casing of the battery pack. The prepared electrolyte was then injected, and the battery was then subjected to processes such as chemical formation and standing to produce a sodium-ion battery.

[0130] Example 27 The composition of the solvent was adjusted to a mixed solution of EC and EMC in a volume ratio of 5:5, and the other conditions were the same as in Example 1.

[0131] Example 28 The procedure was the same as in Example 1, except that diethyl carbonate (DEC) was used in place of EMC in the solvent.

[0132] Example 29 The procedure was the same as in Example 1, except that ethyl propionate was used in place of EMC in the solvent.

[0133] Example 30 The procedure was the same as in Example 1, except that tetrahydrofuran (THF) was used in place of EMC in the solvent.

[0134] Comparative Example 1 The same procedures as in Example 1 were carried out except that Compound 13 was used instead of Compound 1.

[0135] Comparative Example 2 The same procedures as in Example 1 were carried out except that Compound 13 was used instead of Compound 1 and its mass content in the electrolyte was adjusted to 0.5%.

[0136] Comparative Example 3 The same procedures as in Example 1 were carried out except that Compound 13 was used instead of Compound 1 and its mass content in the electrolyte was adjusted to 10%.

[0137] Comparative Example 4 The same procedures as in Example 1 were carried out except that Compound 14 was used instead of Compound 1.

[0138] Comparative Example 5 The same procedures as in Example 1 were carried out except that Compound 15 was used instead of Compound 1.

[0139] Comparative Example 6 The same procedures as in Example 1 were carried out except that Compound 16 was used instead of Compound 1.

[0140] Comparative Example 7 The procedure was the same as in Example 1, except that 1,3-propane sultone (1,3-PS) was used instead of Compound 1.

[0141] Comparative Example 8 The procedure was the same as in Example 26, except that 1,3-PS was used instead of Compound 1.

[0142] Performance test: 1) Cycle performance test The lithium-ion battery was first fully discharged at 1C at 25°C and then tested. The test procedure was as follows: the lithium-ion battery was charged at a constant current of 0.5C to a voltage of 3.65V, then charged at a constant voltage of 3.65V to a current of 0.05C, and after allowing to stand for 5 minutes, the lithium-ion battery was discharged at a constant current of 0.5C to a voltage of 2.5V. This constituted one charge-discharge cycle, and the discharge capacity this time was the discharge capacity of the first cycle. The charge-discharge cycle test of the lithium-ion battery was performed several times according to the above method until the discharge capacity of the lithium-ion secondary battery had decayed to 80%, and the number of cycles of the lithium-ion battery was recorded.

[0143] The sodium-ion battery was first fully discharged at 1C at 25°C and then tested. The test procedure was as follows: the sodium-ion battery was charged at a constant current of 0.5C to a voltage of 3.95V, then charged at a constant voltage of 3.95V to a current of 0.05C, and after allowing to stand for 5 minutes, the sodium-ion battery was discharged at a constant current of 0.5C to a voltage of 1.5V. This constituted one charge-discharge cycle, and the discharge capacity this time was the discharge capacity of the first cycle. The sodium-ion battery was subjected to charge-discharge cycle testing several times according to the above method until the discharge capacity of the sodium-ion battery had decayed to 80%, and the number of cycles of the sodium-ion battery was recorded.

[0144] Battery cycle capacity retention rate (%) = (battery discharge capacity at Nth cycle / battery discharge capacity at first cycle) × 100%.

[0145] 2) Room temperature DCR test At room temperature, a lithium-ion battery was charged to 3.65V at a constant current of 1C, then charged to a constant voltage of 3.65V at a current of 0.05C. After the battery was fully charged, it was left to rest for 5 minutes, then discharged at 1C for 30 minutes (the battery core charge was 50% SOC), and then left to rest for another 5 minutes. The temperature was adjusted to 25°C and the battery was left to rest for 1 hour, at which point the battery core voltage V1 was recorded. The battery was then discharged at 4C for 30 seconds, and the voltage V2 after pulse discharge was recorded. The DCR for 30 seconds at 50% SOC was calculated as DCR = (V1 - V2) / I, where I = 4C.

[0146] At room temperature, a sodium-ion battery was charged to 4.2V at a constant current of 1C, then charged to a constant voltage of 4.2V at a current of 0.05C. After the battery was fully charged, it was left to rest for 5 minutes, then discharged at 1C for 30 minutes (the battery core charge was 50% SOC), and then left to rest for another 5 minutes. The temperature was adjusted to 25°C and the battery was left to rest for 1 hour, at which point the battery core voltage V1 was recorded. The battery was then discharged at 4C for 30 seconds, and the voltage V2 after pulse discharge was recorded. The DCR for 30 seconds at 50% SOC was calculated as DCR = (V1 - V2) / I, where I = 4C.

[0147] The results of the test are recorded in Table 3.

[0148] [Table 3]

[0149] As can be seen from the results of Examples 1 to 12 and Comparative Example 7, the addition of a cyclic sulfate ester-based additive effectively improved the DCR and cycle performance of the battery core. Compared to conventional sultone additives, this additive produced a lower interfacial impedance and higher stability in the SEI formed in the anode. Comparing Example 1 with Comparative Examples 1, 4, 5, and 6, the addition of Compound 1 significantly improved the cycle performance of the battery core. This is because the introduction of substituents such as alkyl groups produces a longer, more elastic SEI in the anode. This prevents SEI damage due to volume changes in the anode during cycling, improving the cycle performance of the battery core.

[0150] As can be seen from the results of Examples 16 to 22, if the additive is too much, a thick SEI is formed in the negative electrode, the conductivity of the electrolyte decreases, the polarization of the battery core increases, and the cycle performance and DCR decrease to a certain extent. When the mass proportion of the cyclic sulfonate ester additive of the present application in the electrolyte is within the above-mentioned preferred range, it can ensure that the battery core has a relatively low DCR and good cycle performance.

[0151] Although the present application has been described with reference to preferred embodiments, various modifications may be made and some equivalents may be substituted without departing from the scope of the present application. In particular, the technical features described in each embodiment may be combined in any manner unless structurally inconsistent. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A non-aqueous electrolyte solution containing an additive, wherein the additive contains a cyclic sulfate ester compound having a structure represented by general formula (I), 【Chemical 1】 Among them, R １ , R ２ , R ３ and R ４ are each independently any one selected from a group having a structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1 to C6 alkyl group, a C1 to C6 haloalkyl group, a C1 to C6 alkoxy group, a C1 to C6 haloalkoxy group, a C2 to C6 alkenyl group, a C2 to C6 ester group, a cyano group, and a sulfonic acid group, and n1 and n2 are each independently any integer from 0 to 2, The general formula (II) is 【Chemistry 2】 and R ５ and R ６ are each independently any one selected from a group having the structure represented by general formula (II), a hydrogen atom, a halogen atom, a C1 to C6 alkyl group, a C1 to C6 haloalkyl group, a C1 to C6 alkoxy group, a C1 to C6 haloalkoxy group, a C2 to C6 alkenyl group, a C2 to C6 ester group, a cyano group, and a sulfonic acid group, and n3 is an integer of 0 to 2, R １ and R ２ is not a hydrogen atom and R ３ and R ４ is not a hydrogen atom at the same time, Or, R １ , R ２ , R ３ , R ４ , R ５ and R ６ satisfies the following conditions: R １ and R ２ are simultaneously hydrogen atoms, and R ３ and R ４ one of which is a hydrogen atom and the other is any one of a group having a structure represented by general formula (II), a halogen atom, a C1-C6 alkyl group, a C1-C6 haloalkyl group, a C1-C6 alkoxy group, a C1-C6 haloalkoxy group, a C2-C6 alkenyl group, a C2-C6 ester group, a cyano group, and a sulfonic acid group, and in the group having a structure represented by general formula (II), R ５ and R ６ is not a hydrogen atom at the same time, Or, R １ , R ２ , R ３ , R ４ , R ５ and R ６ satisfies the following conditions: R ３ and R ４ are simultaneously hydrogen atoms, and R １ and R ２ one of which is a hydrogen atom and the other is any one selected from a group having a structure represented by general formula (II), a halogen atom, a C1 to C6 alkyl group, a C1 to C6 haloalkyl group, a C1 to C6 alkoxy group, a C1 to C6 haloalkoxy group, a C2 to C6 alkenyl group, a C2 to C6 ester group, a cyano group, and a sulfonic acid group, and in the group having a structure represented by general formula (II), R ５ and R ６ is not a hydrogen atom at the same time, Non-aqueous electrolyte.

2. The cyclic sulfate ester compound has a structure represented by general formula (I-1), 【Chemistry 3】 R １ , R ２ , R ３ and R ４ are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1 to C6 alkyl group, a C1 to C6 haloalkyl group, a C1 to C6 alkoxy group, a C1 to C6 haloalkoxy group, a C2 to C6 alkenyl group, a C2 to C6 ester group, a cyano group, and a sulfonic acid group, General formula (II-1) 【Chemistry 4】 and R ５ and R ６ are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1 to C6 alkyl group, a C1 to C6 haloalkyl group, a C1 to C6 alkoxy group, a C1 to C6 haloalkoxy group, a C2 to C6 alkenyl group, a C2 to C6 ester group, a cyano group, and a sulfonic acid group, The nonaqueous electrolyte according to claim 1 .

3. R １ , R ２ , R ３ , R ４ , R ５ and R ６ are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1 to C3 alkyl group, a C1 to C3 haloalkyl group, a C1 to C3 alkoxy group, a C1 to C3 haloalkoxy group, a C2 to C3 alkenyl group, a C1 to C3 ester group, a cyano group, and a sulfonic acid group, Optionally, R １ , R ２ , R ３ , R ４ , R ５ and R ６ are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, a halogen atom, a C1 to C3 alkyl group, and a C1 to C3 haloalkyl group, Optionally, R １ , R ２ , R ３ , R ４ , R ５ and R ６ are each independently any one selected from a group having a structure represented by general formula (II-1), a hydrogen atom, an F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, a propyl group, and an isopropyl group, Alternatively, the group of the structure represented by the general formula (II-1) is 【Chemistry 5】 wherein X is an F atom, a Cl atom, or a Br atom; Optionally, R １ , R ２ , R ３ and R ４ are each independently 【Chemistry 6】 , a hydrogen atom, an F atom, a Cl atom, a Br atom, a methyl group, an ethyl group, a propyl group, and an isopropyl group, and X is an F atom; Further optionally, R １ , R ２ , R ３ and R ４ are each independently 【Chemistry 7】 3. The nonaqueous electrolyte solution according to claim 1, wherein X is any one selected from the group consisting of a hydrogen atom, a methyl group, and an ethyl group, and X is an F atom.

4. The cyclic sulfate ester compound is 【Chemistry 8】 any one or more selected from the compounds The nonaqueous electrolyte according to claim 1 .

5. The mass content of the cyclic sulfate ester compound in the non-aqueous electrolyte is 0.001% to 20%, and optionally 0.1% to 5%. The nonaqueous electrolyte solution according to any one of claims 1 to 4.

6. the non-aqueous electrolyte solution further comprises an electrolyte, optionally comprising an alkali metal salt-based electrolyte, optionally comprising a lithium salt or a sodium salt, optionally comprising one or more selected from the group consisting of lithium hexafluorophosphate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethanesulfonyl)imide, and optionally comprising one or more selected from the group consisting of sodium hexafluorophosphate, sodium difluoro(oxalato)borate, sodium perchlorate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethanesulfonyl)imide, and sodium trifluoromethanesulfonate; The nonaqueous electrolyte solution according to any one of claims 1 to 5.

7. The non-aqueous electrolyte further comprises a non-aqueous solvent, and optionally the non-aqueous solvent comprises one or more selected from the group consisting of cyclic carbonate esters, chain carbonate esters, nitrile solvents, ketone solvents, and sulfone solvents, and optionally the non-aqueous solvent comprises one or more selected from the group consisting of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, diethyl sulfone, tetrahydrofuran, ethylene glycol dimethyl ether, dioxolane, acetone, acetonitrile, and butyronitrile. The nonaqueous electrolyte solution according to any one of claims 1 to 6.

8. the additive further comprises one or more of a sultone compound; The nonaqueous electrolyte solution according to any one of claims 1 to 7.

9. A secondary battery comprising a positive electrode piece, an electrolyte, a separator film, and a negative electrode piece, wherein the electrolyte is the nonaqueous electrolyte according to any one of claims 1 to 8. Secondary battery.

10. An electrical device including a secondary battery, the secondary battery including the secondary battery according to claim 9. Electrical equipment.

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