Non-aqueous electrolyte and battery

Abstract

To overcome the problems of high low-temperature impedance and insufficient high-temperature cycling and storage performance in existing batteries, the present invention provides a non-aqueous electrolyte comprising a solvent, an electrolyte salt, and a compound represented by Structural Formula 1: #imgabs0#. The present invention also provides a battery comprising this non-aqueous electrolyte. By using the compound represented by Structural Formula 1 as an additive, the non-aqueous electrolyte provided by the present invention effectively improves the battery's low-temperature discharge performance, high-temperature cycling performance, and storage performance under high-voltage conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of secondary batteries, and in particular relates to a non-aqueous electrolyte and a battery. Background Art

[0002] As lithium-ion battery applications expand beyond everyday consumer electronics, particularly in lithium-ion electric vehicles and hybrid electric vehicles, high energy and power density batteries have become a key area of ​​future research. To meet the practical application needs of high-voltage electrode materials, higher safety and technical requirements are being placed on the high-voltage electrolyte systems of lithium-ion batteries. The core technology for electrolytes lies in the development of new materials. Therefore, the key to whether new energy vehicles can replace fuel vehicles lies in overcoming battery technology bottlenecks and improving the energy density of power batteries through electrolyte additives while ensuring safety.

[0003] In non-aqueous electrolyte lithium-ion batteries, non-aqueous electrolyte is a key factor affecting the high and low temperature performance of the battery. In particular, the additives in the non-aqueous electrolyte are particularly important for the high and low temperature performance of the battery. During the initial charging process of the lithium-ion battery, the lithium ions in the positive electrode material of the battery are deintercalated and embedded in the carbon negative electrode through the electrolyte. The electrolyte will decompose on the surface of the electrode to generate products that are insoluble in the electrolyte. These products will be deposited on the surface of the electrode to form a passivation film, which is called the solid electrolyte interface film (SEI). The SEI film is Li + The SEI film is a good conductor of electrons and an insulator of electrons, effectively blocking contact between the electrodes and the electrolyte during subsequent cycling, preventing further decomposition of the electrolyte. Therefore, the SEI film determines the performance of lithium-ion batteries. High-voltage electrolytes are a technical bottleneck for high-voltage lithium-ion battery systems. Increasing the battery's operating voltage can increase energy density. However, currently used electrolytes undergo severe oxidative decomposition when the operating voltage exceeds 4.3V, resulting in an increase in the interfacial impedance between the electrode and the electrolyte, thereby deteriorating battery performance. Furthermore, at low temperatures, the battery's impedance increases significantly, hindering improved discharge efficiency. To enhance the various performance characteristics of lithium-ion batteries, many researchers have added various film-forming additives (such as vinylene carbonate, fluoroethylene carbonate, vinyl ethylene carbonate, and 1,3-propane sultone) to the electrolyte to improve the quality of the SEI film, thereby improving various battery performance characteristics. However, existing film-forming additives still fail to meet the low-temperature discharge performance and high-temperature performance requirements of high-energy-density ion batteries under high-voltage conditions. Summary of the Invention

[0004] In view of the problems of high low-temperature impedance and insufficient high-temperature cycle and storage performance of existing batteries, the present invention provides a non-aqueous electrolyte and a battery.

[0005] The technical solutions adopted by the present invention to solve the above technical problems are as follows:

[0006] In one aspect, the present invention provides a non-aqueous electrolyte comprising a solvent, an electrolyte salt, and a compound represented by structural formula 1:

[0007]

[0008] wherein R1 is selected from a hydrogen atom, a C1-C10 saturated hydrocarbon group, a C1-C10 halogenated hydrocarbon group, a C6-C10 aromatic hydrocarbon group, a C3-C10 cyclic sulfate group and its derivatives, a C3-C10 cyclic borate group and its derivatives, a C3-C10 cyclic sulfite group and its derivatives, a C3-C10 cyclic sulfonate group and its derivatives, a C3-C10 cyclic sulfonate group and its derivatives, a C3-C10 cyclic carboxylate group and its derivatives, a C3-C10 cyclic carbonate group and its derivatives, a C3-C10 cyclic phosphate group and its derivatives, a C2-C10 unsaturated hydrocarbon group, or a C1-C10 group containing a cyano group; and R2 and R3 are each independently selected from a C3-C10 cyclic sulfate group and its derivatives directly bonded to a phosphate group, or a C3-C10 cyclic borate group and its derivatives.

[0009] Optionally, R1 is selected from C2~C10 unsaturated hydrocarbon groups, C3~C10 cyclic sulfate groups and derivatives thereof, C3~C10 cyclic borate groups and derivatives thereof, C3~C10 cyclic sulfite groups and derivatives thereof, C3~C10 cyclic sulfonate groups and derivatives thereof, C3~C10 cyclic sulfinate groups and derivatives thereof, C3~C10 cyclic carboxylate groups and derivatives thereof, C3~C10 cyclic carbonate groups and derivatives thereof or C3~C10 cyclic phosphate groups and derivatives thereof.

[0010] Optionally, R1 is selected from Wherein, R7 and R8 are each independently selected from C1-C5 alkylene or C1-C5 halogenated alkylene; X is selected from Among them, R9, R 10 Each is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group.

[0011] Optionally, R2 and R3 are each independently selected from Wherein, R4 and R5 are each independently selected from C1-5 alkylene or C1-5 halogenated alkylene; X is selected from Among them, R6 is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group.

[0012] Optionally, the compound represented by structural formula 1 is selected from one or more of the following compounds:

[0013]

[0014]

[0015]

[0016]

[0017]

[0018] Optional, R1 or Wherein, R7 and R8 are each independently selected from C1-C5 alkylene or C1-C5 halogenated alkylene; Y is selected from Among them, R9, R 10 Each is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group;

[0019] R2 and R3 are each independently selected from Wherein, R4 and R5 are each independently selected from C1-C5 alkylene or C1-C5 halogenated alkylene; X is selected from Among them, R6 is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group.

[0020] Optionally, the compound represented by structural formula 1 is selected from one or more of the following compounds:

[0021]

[0022] Optionally, based on the total mass of the non-aqueous electrolyte being 100%, the added amount of the compound represented by structural formula 1 is 0.05 to 10%.

[0023] Optionally, the non-aqueous electrolyte further comprises an auxiliary additive, wherein the auxiliary additive comprises at least one of a cyclic sulfate compound, a sultone compound, a cyclic carbonate compound, an unsaturated phosphate compound or a nitrile compound;

[0024] Preferably, the cyclic sulfate compound is selected from at least one of vinyl sulfate, propylene sulfate or methyl vinyl sulfate;

[0025] The sultone compound is selected from at least one of 1,3-propane sultone, 1,4-butane sultone or 1,3-propene sultone;

[0026] The cyclic carbonate compound is selected from at least one of vinylene carbonate, ethylene carbonate, fluoroethylene carbonate or the compound shown in structural formula 2.

[0027]

[0028] In the structural formula 2, R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each is independently selected from one of a hydrogen atom, a halogen atom and a C1-C5 group;

[0029] The unsaturated phosphate compound is selected from at least one of the compounds shown in Structural Formula 3:

[0030]

[0031] In the structural formula 3, R 31 、R 32 、R 32 Each independently selected from C1-C5 saturated hydrocarbon group, unsaturated hydrocarbon group, halogenated hydrocarbon group, -Si(C m H 2m+1 )3, m is a natural number from 1 to 3, and R 31 、R 32 、R 33 At least one of them is an unsaturated hydrocarbon group;

[0032] The nitrile compound includes one or more of succinonitrile, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrionitrile, adiponitrile, pimelonitrile, suberonitrile, azelaic acid dinitrile, and sebaconitrile.

[0033] Preferably, the electrolyte salt is selected from LiPF6, LiBOB, LiDFOB, LiPO2F2, LiBF4, LiSbF6, LiAsF6, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, LiN(SO2F)2, LiClO4, LiAlCl4, LiCF3SO3, Li2B 10 Cl 10 , at least one of lower aliphatic carboxylic acid lithium salts.

[0034] Preferably, the concentration of the electrolyte salt is 0.1 mol / L-8 mol / L.

[0035] In another aspect, the present invention provides a battery comprising a positive electrode, a negative electrode, and the non-aqueous electrolyte as described above.

[0036] Optionally, the positive electrode includes a positive electrode active material, and the positive electrode active material includes LiFe 1-x’ M' x’ PO4、LiMn 2-y’ M y’ O4 and LiNi x Co y Mn z M 1-x-y-z One or more of O2, wherein M' is selected from one or more of Mn, Mg, Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, M is selected from one or more of Fe, Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, and 0≤x'<1, 0≤y'≤1, 0≤y≤1, 0≤x≤1, 0≤z≤1, x+y+z≤1.

[0037] According to the non-aqueous electrolyte provided by the present invention, by adding the compound shown in structural formula 1, the film formation quality of the passivation film on the electrode surface can be significantly improved. The passivation film has the characteristics of low impedance and high high-temperature stability, and is well adapted to the application environment of secondary batteries under high voltage conditions, thereby effectively improving the low-temperature discharge performance and high-temperature cycle and storage performance of the battery under high voltage conditions. It should be noted that the inventors have found through experiments that when the phosphate ester is the central group and at least two of the three groups directly bonded to the outside are cyclic sulfates and their derivatives or cyclic borate esters and their derivatives, the battery has a significant improvement effect. When the number of cyclic sulfates and their derivatives or cyclic borate esters and their derivatives in R1, R2, and R3 is insufficient, the improvement effect on the battery will be significantly reduced, indicating that there is a certain interaction between the number of cyclic sulfates and their derivatives or cyclic borate esters and their derivatives and the phosphate group, and this interaction has a positive promoting effect on the film formation quality of the passivation film. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0039] The term "halogenated hydrocarbon group" refers to a hydrocarbon group in which at least one hydrogen atom is replaced by a halogen atom, wherein the halogen atom is selected from one or more of fluorine, chlorine, bromine and iodine.

[0040] The term "hydrocarbyloxy" refers to a group consisting of a hydrocarbon group and an oxygen group linked together.

[0041] The term "cyclic carbonate groups and derivatives thereof" refers to groups containing a cyclic carbon chain in which one or more carbon atoms are replaced by a carbonate group, as well as groups in which one or more hydrogen atoms are replaced by a hydrogen group. The substituted groups may be hydrocarbon groups, halogens, halogenated hydrocarbon groups, etc. "Cyclic borate groups and derivatives thereof," "cyclic phosphate groups and derivatives thereof," "cyclic carboxylate groups and derivatives thereof," "cyclic sulfite groups and derivatives thereof," "cyclic sulfate groups and derivatives thereof," "cyclic sulfonate groups and derivatives thereof," and "cyclic sulfinate groups and derivatives thereof" can be understood in accordance with this definition.

[0042] One embodiment of the present invention provides a non-aqueous electrolyte solution comprising a solvent, an electrolyte salt, and a compound shown in structural formula 1:

[0043]

[0044] wherein R1 is selected from a hydrogen atom, a C1-C10 saturated hydrocarbon group, a C1-C10 halogenated hydrocarbon group, a C6-C10 aromatic hydrocarbon group, a C3-C10 cyclic sulfate group and its derivatives, a C3-C10 cyclic borate group and its derivatives, a C3-C10 cyclic sulfite group and its derivatives, a C3-C10 cyclic sulfonate group and its derivatives, a C3-C10 cyclic sulfonate group and its derivatives, a C3-C10 cyclic carboxylate group and its derivatives, a C3-C10 cyclic carbonate group and its derivatives, a C3-C10 cyclic phosphate group and its derivatives, a C2-C10 unsaturated hydrocarbon group, or a C1-C10 group containing a cyano group; and R2 and R3 are each independently selected from a C3-C10 cyclic sulfate group and its derivatives directly bonded to a phosphate group, or a C3-C10 cyclic borate group and its derivatives.

[0045] The non-aqueous electrolyte provided by the present invention adds the compound shown in structural formula 1 as an additive, which can significantly improve the film-forming quality of the passivation film on the electrode surface. The passivation film has the characteristics of low impedance and high high-temperature stability, and is well adapted to the application environment of secondary batteries under high voltage conditions, thereby effectively improving the low-temperature discharge performance and high-temperature cycle and storage performance of the battery under high voltage conditions. It should be noted that the inventors found through experiments that when the phosphate ester is the central group and at least two of the three groups directly bonded to the outside are cyclic sulfates and their derivatives or cyclic borate esters and their derivatives, the compound shown in structural formula 1 has the above-mentioned battery-enhancing effect. When the number of cyclic sulfates and their derivatives or cyclic borate esters and their derivatives in R1, R2, and R3 is insufficient, the battery-enhancing effect will be significantly reduced, indicating that there is a certain interaction between the number of cyclic sulfates and their derivatives or cyclic borate esters and their derivatives and the phosphate group, and this interaction has a positive promoting effect on the film-forming quality of the passivation film.

[0046] In some embodiments, R2 and R3 are the same and are both selected from C3-C10 cyclic sulfate groups and their derivatives.

[0047] In some embodiments, R2 and R3 are the same and are both selected from C3-C10 cyclic borate groups and derivatives thereof.

[0048] In some embodiments, R2 and R3 are different, one of which is selected from C3-C10 cyclic sulfate groups and their derivatives, and the other is selected from C3-C10 cyclic borate groups and their derivatives.

[0049] In some embodiments, R1 is selected from C2-C10 unsaturated hydrocarbon groups, C3-C10 cyclic sulfate groups and derivatives thereof, C3-C10 cyclic borate groups and derivatives thereof, C3-C10 cyclic sulfite groups and derivatives thereof, C3-C10 cyclic sulfonate groups and derivatives thereof, C3-C10 cyclic sulfonate groups and derivatives thereof, C3-C10 cyclic sulfinate groups and derivatives thereof, C3-C10 cyclic carboxylate groups and derivatives thereof, C3-C10 cyclic carbonate groups and derivatives thereof, or C3-C10 cyclic phosphate groups and derivatives thereof.

[0050] In some embodiments, R1 is selected from Wherein, R7 and R8 are each independently selected from C1-C5 alkylene or C1-C5 halogenated alkylene; X is selected from Among them, R9, R 10Each is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group.

[0051] In some embodiments, the sum of the carbon number of R7 and R8 is less than or equal to 6.

[0052] R7 and R8 are carbon chains on R1. If the sum of the number of carbon atoms of R7 and R8 is too large, the stability of the cyclic group R1 will decrease. When the sum of the number of carbon atoms of R7 and R8 is less than or equal to 6, the cyclic group R1 will be in a better stable state, which is conducive to the performance of its function.

[0053] In some embodiments, R2 and R3 are each independently selected from Wherein, R4 and R5 are each independently selected from C1-C5 alkylene or C1-C5 halogenated alkylene; X is selected from Among them, R6 is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group.

[0054] Specifically, the compound represented by the structural formula 1 is selected from the compounds represented by the following structural formulas:

[0055]

[0056] wherein R1 is selected from a hydrogen atom, a C1-C10 saturated hydrocarbon group, a C1-C10 halogenated hydrocarbon group, a C6-C10 aromatic hydrocarbon group, a C3-C10 cyclic sulfate group and its derivatives, a C3-C10 cyclic borate group and its derivatives, a C3-C10 cyclic sulfite group and its derivatives, a C3-C10 cyclic sulfonate group and its derivatives, a C3-C10 cyclic sulfinate group and its derivatives, a C3-C10 cyclic carboxylate group and its derivatives, a C3-C10 cyclic carbonate group and its derivatives, a C3-C10 cyclic phosphate group and its derivatives, a C2-C10 unsaturated hydrocarbon group, or a C1-C10 group containing a cyano group; R4, R5, R'4, and R'5 are each independently selected from a C1-C5 alkylene group or a C1-C5 halogenated alkylene group; and X and X' are each independently selected from Among them, R6 is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group.

[0057] In some embodiments, R6, R9, R 10 and each is independently selected from fluoromethyl, fluoroethyl, fluoropropyl, fluorobutyl, fluoropentyl, fluorohexyl, fluoroheptyl, fluoromethoxy, fluoroethoxy, fluoropropoxy, fluorobutoxy, fluoropentyloxy, fluorohexyloxy, fluoroheptyloxy, fluorobenzyloxy, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, propenyl, butenyl, pentenyl, propynyl, butynyl, pentynyl, methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, or 2-cyanoethyl.

[0058] In some embodiments, R6, R9, R 10 Each is independently selected from a hydrogen atom, a C1-C7 hydrocarbyloxy group, a C1-C7 halogenated hydrocarbyloxy group, or a C1-C7 halogenated hydrocarbyl group.

[0059] In some embodiments, R4, R5, R7, and R8 are each independently selected from fluoromethylene, fluoroethylene, fluoropropylene, fluorobutylene, methylene, ethylene, vinylene, propylene, or butylene.

[0060] In some embodiments, the compound represented by Structural Formula 1 is selected from one or more of the following compounds:

[0061]

[0062]

[0063]

[0064]

[0065]

[0066] In some embodiments, R1 is selected from C2 to C10 unsaturated hydrocarbon groups or Wherein, R7 and R8 are each independently selected from C1-C5 alkylene or C1-C5 halogenated alkylene; Y is selected from Among them, R9, R 10Each is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group;

[0067] R2 and R3 are each independently selected from Wherein, R4 and R5 are each independently selected from C1-C5 alkylene or C1-C5 halogenated alkylene; X is selected from Among them, R6 is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group.

[0068] In a preferred embodiment, the compound represented by structural formula 1 is selected from one or more of the following compounds:

[0069]

[0070] It should be noted that the above are only some embodiments protected by the present invention and should not be understood as limiting the present invention.

[0071] A person skilled in the art, knowing the structural formula of the compound of Structural Formula 1, can know the preparation method of the above compound based on common knowledge in the field of chemical synthesis. As an example of the present invention:

[0072] The compound represented by structural formula 1 can be obtained by performing a double decomposition reaction between phosphorus oxychloride and one or more of R1-OH, R2-OH and R3-OH in the presence of an acid binding agent.

[0073] In some embodiments, based on the total mass of the non-aqueous electrolyte being 100%, the added amount of the compound represented by Structural Formula 1 is 0.05-10%.

[0074] In a preferred embodiment, based on the total mass of the non-aqueous electrolyte being 100%, the added amount of the compound represented by structural formula 1 is 0.1-5%.

[0075] Specifically, the addition amount of the compound represented by structural formula 1 can be 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 7.8%, 8%, 8.5%, 9%, 9.5%, or 10%.

[0076] Within the above range, the compound represented by Structural Formula 1 can significantly improve the high-temperature storage performance and high-temperature cycle performance of the battery, while also achieving low impedance and no bloating. When the addition amount of the compound represented by Structural Formula 1 is less than 0.05%, the content of Structural Formula 1 in the electrolyte is too low to form a complete passivation film on the surface of the positive electrode, making it difficult to significantly improve the high-temperature performance of the non-aqueous electrolyte battery, and the battery internal resistance does not significantly decrease. When the addition amount of the compound represented by Structural Formula 1 exceeds 10.0%, an excessively thick passivation film is easily formed on the surface of the positive electrode, which in turn increases the internal resistance of the battery, and the battery capacity retention rate is significantly deteriorated.

[0077] In some embodiments, the non-aqueous electrolyte further comprises an auxiliary additive, wherein the auxiliary additive comprises at least one of a cyclic sulfate compound, a sultone compound, a cyclic carbonate compound, an unsaturated phosphate compound, or a nitrile compound;

[0078] Preferably, the cyclic sulfate compound is selected from at least one of vinyl sulfate, propylene sulfate or methyl vinyl sulfate;

[0079] The sultone compound is selected from at least one of 1,3-propane sultone, 1,4-butane sultone or 1,3-propene sultone;

[0080] The cyclic carbonate compound is selected from at least one of vinylene carbonate, ethylene carbonate, fluoroethylene carbonate or the compound shown in structural formula 2.

[0081]

[0082] In the structural formula 2, R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each is independently selected from one of a hydrogen atom, a halogen atom and a C1-C5 group.

[0083] The unsaturated phosphate compound is selected from at least one of the compounds shown in Structural Formula 3:

[0084]

[0085] In the structural formula 3, R 31 、R 32 、R 32 Each independently selected from C1-C5 saturated hydrocarbon group, unsaturated hydrocarbon group, halogenated hydrocarbon group, -Si(C m H 2m+1 )3, m is a natural number from 1 to 3, and R 31 、R32 、R 33 At least one of them is an unsaturated hydrocarbon group;

[0086] In a preferred embodiment, the unsaturated phosphate compound may be at least one of tripropargyl phosphate, dipropargyl methyl phosphate, dipropargyl ethyl phosphate, dipropargyl propyl phosphate, dipropargyl trifluoromethyl phosphate, dipropargyl-2,2,2-trifluoroethyl phosphate, dipropargyl-3,3,3-trifluoropropyl phosphate, dipropargyl hexafluoroisopropyl phosphate, triallyl phosphate, diallyl methyl phosphate, diallyl ethyl phosphate, diallyl propyl phosphate, diallyl trifluoromethyl phosphate, diallyl-2,2,2-trifluoroethyl phosphate, diallyl-3,3,3-trifluoropropyl phosphate, and diallyl hexafluoroisopropyl phosphate.

[0087] In a preferred embodiment, the nitrile compound includes one or more of succinonitrile, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrionitrile, adiponitrile, pimelonitrile, suberonitrile, azelaic acid dinitrile, and sebaconitrile.

[0088] The auxiliary additive can be used in combination with the compound shown in Structural Formula 1 to form a more stable SEI film on the surface of the graphite negative electrode, thereby significantly improving the cycle performance of the lithium-ion battery, and can achieve better results than adding the compound shown in Structural Formula 1 alone.

[0089] It should be noted that, unless otherwise specified, under normal circumstances, the amount of any one of the optional substances in the auxiliary additives added to the non-aqueous electrolyte is 0.05-10%, preferably, the amount added is 0.1-5%, and more preferably, the amount added is 0.1%-3%. Specifically, the amount of any one of the optional substances in the auxiliary additives can be 0.05%, 0.08%, 0.1%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 7.8%, 8%, 8.5%, 9%, 9.5%, or 10%.

[0090] In some embodiments, when the auxiliary additive is selected from fluoroethylene carbonate, the amount of the auxiliary additive added is 0.05% to 30% based on the total mass of the non-aqueous electrolyte as 100%.

[0091] In some embodiments, the solvent includes one or more of an ether solvent, a nitrile solvent, a carbonate solvent, a carboxylate solvent, and a sulfone solvent.

[0092] In some embodiments, the ether solvent includes a cyclic ether or a chain ether, preferably a chain ether with 3 to 10 carbon atoms and a cyclic ether with 3 to 6 carbon atoms. The cyclic ether may be, but is not limited to, one or more of 1,3-dioxolane (DOL), 1,4-dioxolane (DX), crown ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-CH3-THF), and 2-trifluoromethyltetrahydrofuran (2-CF3-THF). The chain ether may be, but is not limited to, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether. Because chain ethers have high solvation ability with lithium ions and can improve ion dissociation, dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are particularly preferred because they have low viscosity and can impart high ionic conductivity. The ether compound can be used alone or in any combination and ratio. There is no special restriction on the amount of ether compound added, and it is arbitrary within the range that does not significantly damage the effect of the high-density lithium-ion battery of the present invention. The volume ratio is usually 1% or more, preferably 2% or more, and more preferably 3% or more in the non-aqueous solvent volume ratio of 100%. In addition, the volume ratio is usually 30% or less, preferably 25% or less, and more preferably 20% or less. When two or more ether compounds are used in combination, the total amount of the ether compounds can be made to meet the above range. When the amount of ether compound added is within the above-mentioned preferred range, it is easy to ensure the improvement effect of ion conductivity brought about by the increase in the lithium ion dissociation degree of the chain ether and the reduction in viscosity. In addition, when the negative electrode active material is a carbon material, the phenomenon of co-embedding of the chain ether and lithium ions can be suppressed, so that the input-output characteristics and charge-discharge rate characteristics can be brought into an appropriate range.

[0093] In some embodiments, the nitrile solvent may be, but is not limited to, one or more of acetonitrile, glutaronitrile, and malononitrile.

[0094] In some embodiments, the carbonate solvent includes a cyclic carbonate or a chain carbonate. The cyclic carbonate may be, but is not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL), and butylene carbonate (BC); the chain carbonate may be, but is not limited to, one or more of dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and dipropyl carbonate (DPC). The content of the cyclic carbonate is not particularly limited and is arbitrary within a range that does not significantly impair the effect of the high-density lithium-ion battery of the present invention. However, when using a single carbonate, the lower limit of its content is generally 3% or more by volume, preferably 5% or more by volume, relative to the total amount of solvent in the non-aqueous electrolyte. By setting this range, the decrease in conductivity caused by the decrease in the dielectric constant of the non-aqueous electrolyte can be avoided, making it easier to achieve good high-current discharge characteristics, stability relative to the negative electrode, and cycle characteristics of the non-aqueous electrolyte battery. In addition, the upper limit is generally 90% or less by volume, preferably 85% or less by volume, and more preferably 80% or less by volume. By setting this scope, the oxidation / reduction tolerance of nonaqueous electrolyte can be improved, thereby contributing to the stability during high temperature storage. The content of linear carbonate is not particularly limited, and relative to the total amount of solvent of nonaqueous electrolyte, is usually more than 15% by volume, preferably more than 20% by volume, and more preferably more than 25% by volume. In addition, usually the volume ratio is less than 90%, preferably less than 85% by volume, and more preferably less than 80% by volume. By making the content of linear carbonate in the above-mentioned scope, it is easy to make the viscosity of nonaqueous electrolyte reach appropriate range, suppress the reduction of ionic conductivity, and then contribute to the output characteristics of nonaqueous electrolyte battery reach good scope. When using two or more linear carbonates in combination, make the total amount of linear carbonate meet the above-mentioned scope.

[0095] In certain embodiments, also can preferably use the linear carbonates with fluorine atoms (hereinafter referred to as " fluorinated linear carbonate ").The number of the fluorine atoms possessed by fluorinated linear carbonate is as long as being more than 1 then has no particular restrictions, but is generally below 6, preferably below 4.When fluorinated linear carbonate has a plurality of fluorine atoms, these fluorine atoms can be bonded on the same carbon, also can be bonded on different carbons.As fluorinated linear carbonate, can enumerate, fluorinated dimethyl carbonate derivatives, fluorinated ethyl methyl carbonate derivatives, fluorinated diethyl carbonate derivatives etc.

[0096] Carboxylate solvents include cyclic carboxylates and / or chain carbonates. Examples of cyclic carboxylates include one or more of γ-butyrolactone, γ-valerolactone, and δ-valerolactone. Examples of chain carbonates include one or more of methyl acetate (MA), ethyl acetate (EA), propyl acetate (EP), butyl acetate, propyl propionate (PP), and butyl propionate.

[0097] In some embodiments, the sulfone solvent includes cyclic sulfones and chain sulfones. Preferably, the cyclic sulfone is a compound having 3 to 6 carbon atoms, preferably 3 to 5 carbon atoms, while the chain sulfone is a compound having 2 to 6 carbon atoms, preferably 2 to 5 carbon atoms. The amount of the sulfone solvent added is not particularly limited and may be any amount that does not significantly impair the high-density lithium-ion battery performance of the present invention. The volume ratio relative to the total volume of the non-aqueous electrolyte solvent is generally 0.3% or more, preferably 0.5% or more, and more preferably 1% or more. Furthermore, the volume ratio is generally 40% or less, preferably 35% or less, and more preferably 30% or less. When two or more sulfone solvents are used in combination, the total amount of the sulfone solvents may be within the above range. When the amount of the sulfone solvent added is within the above range, an electrolyte solution with excellent high-temperature storage stability tends to be obtained.

[0098] In a preferred embodiment, the solvent is a mixture of cyclic carbonate and chain carbonate.

[0099] In some embodiments, the electrolyte salt includes one or more of lithium salt, sodium salt, potassium salt, magnesium salt, zinc salt and aluminum salt. In a preferred embodiment, the electrolyte salt is selected from lithium salt or sodium salt.

[0100] In a preferred embodiment, the lithium salt is selected from LiPF6, LiBOB, LiDFOB, LiPO2F2, LiBF4, LiSbF6, LiAsF6, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, LiN(SO2F)2, LiClO4, LiAlCl4, LiCF3SO3, Li2B 10 Cl 10 , or at least one of a lithium salt of a lower aliphatic carboxylate. If the electrolyte salt is selected from other salts such as sodium salt, potassium salt, magnesium salt, zinc salt or aluminum salt, the lithium in the lithium salt can be replaced with sodium, potassium, magnesium, zinc or aluminum.

[0101] In a preferred embodiment, the sodium salt is selected from at least one of sodium perchlorate (NaClO4), sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium trifluoromethanesulfonate (NaFSI), and sodium bistrifluoromethanesulfonate (NaTFSI).

[0102] In some embodiments, the concentration of the electrolyte salt in the non-aqueous electrolyte is 0.1 mol / L to 8 mol / L. In a preferred embodiment, the concentration of the electrolyte salt in the non-aqueous electrolyte is 0.5 mol / L to 2.5 mol / L. Specifically, the concentration of the electrolyte salt can be 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, or 2.5 mol / L.

[0103] Another embodiment of the present invention provides a battery including a positive electrode, a negative electrode, and the non-aqueous electrolyte as described above.

[0104] Since the battery adopts the non-aqueous electrolyte as described above, it can form a passivation film with excellent performance on the positive electrode and the negative electrode, thereby effectively improving the high-temperature storage performance and high-temperature cycle performance of the battery and enhancing the battery power characteristics.

[0105] In some embodiments, the battery is a secondary battery, which may be a lithium secondary battery, a potassium secondary battery, a sodium secondary battery, a magnesium secondary battery, a zinc secondary battery, an aluminum secondary battery, or the like.

[0106] In a preferred embodiment, the battery is a lithium metal battery, a lithium ion battery, a lithium sulfur battery, or a sodium ion battery.

[0107] In some embodiments, the positive electrode includes a positive electrode active material layer, and the positive electrode active material layer includes a positive electrode active material. The type of the positive electrode active material is not particularly limited and can be selected according to actual needs, as long as it is a positive electrode active material or a conversion-type positive electrode material that can reversibly embed / de-embed metal ions (lithium ions, sodium ions, potassium ions, magnesium ions, zinc ions, aluminum ions, etc.).

[0108] In a preferred embodiment, the battery is a lithium-ion battery, and its positive electrode active material can be selected from LiFe 1-x’ M' x’ PO4、LiMn 2-y’ M y’ O4 and LiNi x Co y Mn z M 1-x-y-zO2, wherein M' is selected from one or more of Mn, Mg, Co, Ni, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, M is selected from one or more of Fe, Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V or Ti, and 0≤x'<1, 0≤y'≤1, 0≤y≤1, 0≤x≤1, 0≤z≤1, x+y+z≤1, the positive electrode active material can also be selected from one or more of sulfide, selenide, and halide. More preferably, the positive electrode active material can be selected from LiCoO2, LiFePO4, LiFe 0.8 Mn 0.2 PO4、LiNi 0.5 Co 0.2 Mn 0.3 O2、LiNi 0.6 Co 0.2 Mn 0.2 O2、LiNi 0.8 Co 0.1 Mn 0.1 O2、LiNi 0.5 Co 0.2 Mn 0.2 Al 0.1 O2, LiMn2O4, LiNi 0.5 Co 0.2 Al 0.3 One or more of O2.

[0109] In a preferred embodiment, the battery is a sodium ion battery, and its positive electrode active material can be selected from one or more of metallic sodium, carbon materials, alloy materials, overplated metal oxides, overplated metal sulfides, phosphorus-based materials, titanate materials, and Prussian blue materials. The carbon material can be selected from one or more of graphite, soft carbon, and hard carbon. The alloy material can be selected from an alloy material composed of at least two of Si, Ge, Sn, Pb, and Sb. The alloy material can also be selected from an alloy material composed of at least one of Si, Ge, Sn, Pb, and Sb and C. The chemical formula of the overplated metal oxide and the overplated metal sulfide is M1 x N y , M1 can be selected from one or more of Fe, Co, Ni, Cu, Mn, Sn, Mo, Sb, V, N is selected from O or S, the phosphorus-based material can be selected from one or more of red phosphorus, white phosphorus, and black phosphorus, the titanate material can be selected from Na2Ti3O7, Na2Ti6O 13 、Na4Ti5O 12 、Li4Ti5O 12 , NaTi2(PO4)3, wherein the molecular formula of the Prussian blue material is Nax M[M′(CN)6] y ·zH2O, where M is a transition metal, M′ is a transition metal, 0 <x≤2,0.8≤y<1,0<z≤20。

[0110] In some embodiments, the positive electrode further includes a positive electrode current collector, and the positive electrode material layer covers a surface of the positive electrode current collector.

[0111] The positive electrode current collector is selected from a metal material that can conduct electrons. Preferably, the positive electrode current collector includes one or more of Al, Ni, tin, copper, and stainless steel. In a more preferred embodiment, the positive electrode current collector is selected from aluminum foil.

[0112] In some embodiments, the positive electrode active material layer further includes a positive electrode binder and a positive electrode conductor, and the positive electrode active material, the positive electrode binder and the positive electrode conductor are blended to obtain the positive electrode active material layer.

[0113] The positive electrode binder includes polyvinylidene fluoride, a copolymer of vinylidene fluoride, polytetrafluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene, a copolymer of tetrafluoroethylene-hexafluoropropylene, a copolymer of tetrafluoroethylene-perfluoroalkyl vinyl ether, a copolymer of ethylene-tetrafluoroethylene, a copolymer of vinylidene fluoride-tetrafluoroethylene, a copolymer of vinylidene fluoride-trifluoroethylene, a copolymer of vinylidene fluoride-trichloroethylene, a copolymer of vinylidene fluoride-fluoroethylene, a copolymer of vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene, thermoplastic polyimide, a thermoplastic resin such as polyethylene and polypropylene; an acrylic resin; and one or more of styrene butadiene rubber.

[0114] The positive electrode conductive agent includes one or more of conductive carbon black, conductive carbon balls, conductive graphite, conductive carbon fibers, carbon nanotubes, graphene, or reduced graphene oxide.

[0115] In some embodiments, the negative electrode includes a negative electrode material layer, the negative electrode material layer including a negative electrode active material, and the negative electrode active material includes one or more of a silicon-based negative electrode, a carbon-based negative electrode, a tin-based negative electrode, and a lithium negative electrode. The silicon-based negative electrode includes one or more of silicon materials, silicon oxides, silicon-carbon composite materials, and silicon alloy materials; the carbon-based negative electrode includes one or more of graphite, hard carbon, soft carbon, graphene, and mesocarbon microbeads; the tin-based negative electrode includes one or more of tin, tin-carbon, tin oxide, and tin metal compounds; and the lithium negative electrode includes one or more of metallic lithium or a lithium alloy. The lithium alloy can specifically be at least one of a lithium-silicon alloy, a lithium-sodium alloy, a lithium-potassium alloy, a lithium-aluminum alloy, a lithium-tin alloy, and a lithium-indium alloy.

[0116] In some embodiments, the negative electrode further comprises a negative electrode current collector, and the negative electrode material layer covers the surface of the negative electrode current collector. The material of the negative electrode current collector can be the same as that of the positive electrode current collector, which will not be repeated here.

[0117] In some embodiments, the negative electrode material layer further includes a negative electrode binder and a negative electrode conductive agent. The negative electrode active material, the negative electrode binder, and the negative electrode conductive agent are blended together to form the negative electrode material layer. The negative electrode binder and the negative electrode conductive agent may be the same as the positive electrode binder and the positive electrode conductive agent, respectively, and are not further described here.

[0118] In some embodiments, the battery further includes a separator, which is located between the positive electrode and the negative electrode.

[0119] The diaphragm can be an existing conventional diaphragm, which can be a ceramic diaphragm, a polymer diaphragm, a non-woven fabric, an inorganic-organic composite diaphragm, etc., including but not limited to single-layer PP (polypropylene), single-layer PE (polyethylene), double-layer PP / PE, double-layer PP / PP and three-layer PP / PE / PP diaphragms.

[0120] The present invention is further described below with reference to the following examples.

[0121] Table 1

[0122]

[0123] Note: The compounds used in the following examples and comparative examples are selected from Table 1.

[0124] Examples 1 to 15

[0125] This embodiment is used to illustrate the electrolyte, battery and preparation method disclosed in the present invention, including the following steps:

[0126] 1) Preparation of non-aqueous electrolyte

[0127] Ethylene carbonate (EC), diethyl carbonate (DEC) and ethyl methyl carbonate (EMC) were mixed in a mass ratio of EC:DEC:EMC = 1:1:1, and then lithium hexafluorophosphate (LiPF6) was added to a molar concentration of 1 mol / L. Based on the total weight of the non-aqueous electrolyte being 100%, additives were added in the mass percentages shown in Examples 1 to 15 in Table 2.

[0128] 2) Preparation of positive electrode sheet

[0129] The positive electrode active material lithium nickel cobalt manganese oxide LiNi was mixed in a mass ratio of 93:4:3 0.5 Co 0.2 Mn 0.3O2, conductive carbon black Super-P, and binder polyvinylidene fluoride (PVDF) are then dispersed in N-methyl-2-pyrrolidone (NMP) and mixed evenly to prepare the positive electrode slurry for lithium-ion batteries. The positive electrode slurry is evenly coated on both sides of the positive electrode current collector aluminum foil, dried, rolled, and vacuum-dried. After trimming, cutting, and slitting, aluminum lead wires are welded with an ultrasonic welder to obtain the positive electrode sheet, which is between 120-150μm thick.

[0130] 3) Preparation of negative electrode sheet

[0131] The negative electrode active material, artificial graphite, the conductive agent, conductive carbon black Super-P, the binder, styrene-butadiene rubber (SBR), and the thickener, carboxymethyl cellulose (CMC), are mixed in a mass ratio of 94:1:2.5:2.5 and then dispersed in deionized water to create the negative electrode slurry. The slurry is coated on both sides of the copper foil, dried, rolled, and vacuum-dried. After trimming, cutting, and slitting, nickel lead wires are welded to the negative electrode sheet using an ultrasonic welder. The thickness of the negative electrode sheet is between 120-150μm.

[0132] 4) Preparation of battery cells

[0133] A three-layer lithium battery separator with a thickness of 20 μm was placed between the positive electrode sheet and the negative electrode sheet prepared above, and the sandwich structure consisting of the positive electrode sheet, the negative electrode sheet and the separator was wound. The wound body was flattened and placed in an aluminum foil packaging bag, and vacuum-baked at 75°C for 48 hours to obtain a battery cell to be injected with liquid.

[0134] 5) Battery filling and formation

[0135] In a glove box with a dew point controlled below -40°C, the prepared electrolyte was injected into the dried battery cell, vacuum sealed, and left to stand for 24 hours. Then, the conventional formation of the first charge was carried out according to the following steps: 0.05C constant current charging for 180 minutes, 0.2C constant current charging to 3.95V, secondary vacuum sealing, and then further 0.2C constant current charging to 4.2V. After standing at room temperature for 24 hours, it was discharged at 0.2C constant current to 3.0V to obtain a LiNi 0.5 Co 0.2 Mn 0.3 O2 / artificial graphite lithium-ion battery.

[0136] Comparative Examples 1 to 7

[0137] This example is used to compare and illustrate the non-aqueous electrolyte and battery method disclosed in the present invention, and includes most of the operating steps in Example 1, except that:

[0138] In the preparation of the non-aqueous electrolyte, additives were added in the mass percentages shown in Comparative Examples 1 to 7 in Table 2.

[0139] Performance Testing

[0140] The lithium-ion batteries prepared in Examples 1-15 and Comparative Examples 1-7 were subjected to the following performance tests:

[0141] 1) High temperature cycle performance test:

[0142] At 45°C, the formed battery is charged to 4.2V (LiNi 0.5 Co 0.2 Mn 0.3 O2 / artificial graphite battery), then charge at constant voltage until the current drops to 0.02C, then discharge at a constant current of 1C to 3.0V, and repeat this cycle, recording the first discharge capacity and the last discharge capacity.

[0143] The capacity retention rate of high temperature cycle is calculated as follows:

[0144] Capacity retention rate = last discharge capacity / first discharge capacity × 100%.

[0145] 2) High temperature storage performance test

[0146] The formed lithium-ion battery is charged to 4.2V (LiNi 0.5 Co 0.2 Mn 0.3 O2 / artificial graphite battery), measure the initial discharge capacity and initial battery thickness of the battery, and then store it in a 60℃ environment for 30 days, discharge it to 3V at 1C, and measure the battery's retention capacity, recovery capacity and battery thickness after storage.

[0147] The calculation formula is as follows:

[0148] Battery capacity retention rate (%) = retained capacity / initial capacity × 100%;

[0149] Battery capacity recovery rate (%) = recovery capacity / initial capacity × 100%;

[0150] Thickness expansion ratio (%) = (battery thickness after storage - initial battery thickness) / initial battery thickness × 100%.

[0151] 3) Low temperature discharge performance test

[0152] At 25°C, the formed lithium-ion battery was charged to 4.2V using a 1C constant current and constant voltage charge with a cutoff current of 0.01C. It was then discharged to 3.0V using a 0.2C constant current charge, and the discharge capacity was recorded. The battery was then charged to 4.2V using a 1C constant current and constant voltage charge. The battery was then placed in a -20°C environment for 12 hours, and then discharged to 3.0V using a 0.2C constant current charge, and the discharge capacity was recorded.

[0153] The formula for calculating the discharge efficiency at -20℃ 0.2C is as follows:

[0154] Low-temperature discharge efficiency at -20°C (%) = 0.2C discharge capacity (-20°C) / 0.2C discharge capacity (25°C).

[0155] Fill in the test results in Table 2.

[0156] Table 2

[0157]

[0158]

[0159] By comparing the test results of Examples 1 to 8 and Comparative Examples 1 to 4, it can be seen that compared with lithium ion batteries without additives or with existing additives, the lithium ion batteries obtained by using the compound of Structural Formula 1 provided by the present invention as an additive have better high-temperature cycling and high-temperature storage performance, and according to the low-temperature discharge efficiency, it can be seen that after adding the compound represented by Structural Formula 1, the low-temperature discharge performance of the battery is also improved, the charge and discharge performance and cycle number of the battery are improved, and the battery has good high and low temperature adaptability.

[0160] By comparing the test results of Example 1 and Examples 9 to 12, it can be seen that as the addition amount of the compound represented by Structural Formula 1 increases, the performance improvement of the lithium-ion battery first increases and then decreases, indicating that excessive or insufficient addition will lead to improvements in both the high-temperature performance and the low-temperature performance of the lithium-ion battery. When the addition amount of the compound represented by Structural Formula 1 is between 1% and 2%, the resulting lithium-ion battery has the best high and low-temperature performance.

[0161] By comparing the data of Examples 13 to 15 and Comparative Examples 2 to 4, it can be seen that compared with adding the compound represented by Structural Formula 1 alone in Example 1, when the compound represented by Structural Formula 1 and FEC (or VEC, VC) are added to the non-aqueous electrolyte at the same time, FEC (or VEC, VC) can synergistically act with the compound represented by Structural Formula 1 to form a more stable SEI film on the surface of the graphite negative electrode, so that the lithium-ion battery has good high temperature performance and high temperature storage performance, significantly improves the cycle performance of the lithium-ion battery, especially the low temperature performance is significantly improved.

[0162] By comparing the test results of Examples 1 to 8 and Comparative Examples 5-7, it can be seen that in compounds similar to the compound shown in Structural Formula 1, when the number of cyclic sulfate groups or borate groups in R1, R2, and R3 is less than 2, the battery improvement effect will be significantly reduced, indicating that the number of cyclic sulfate groups or borate groups is directly related to the performance of the compound shown in Structural Formula 1.

[0163] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A non-aqueous electrolyte, characterized in that It includes a solvent, an electrolyte salt and a compound shown in structural formula 1: Structural formula 1 wherein R1 is selected from a hydrogen atom, a C1-C10 saturated hydrocarbon group, a C1-C10 halogenated hydrocarbon group, a C6-C10 aromatic hydrocarbon group, a C3-C10 cyclic sulfate group and its derivatives, a C3-C10 cyclic borate group and its derivatives, a C3-C10 cyclic sulfite group and its derivatives, a C3-C10 cyclic sulfonate group and its derivatives, a C3-C10 cyclic sulfonate group and its derivatives, a C3-C10 cyclic carboxylate group and its derivatives, a C3-C10 cyclic carbonate group and its derivatives, a C3-C10 cyclic phosphate group and its derivatives, a C2-C10 unsaturated hydrocarbon group, or a C1-C10 group containing a cyano group; and R2 and R3 are each independently selected from a C3-C10 cyclic borate group and its derivatives directly bonded to a phosphate group.

2. The non-aqueous electrolyte according to claim 1, characterized in that R1 is selected from a C2-C10 unsaturated hydrocarbon group, a C3-C10 cyclic sulfate group and its derivatives, a C3-C10 cyclic borate group and its derivatives, a C3-C10 cyclic sulfite group and its derivatives, a C3-C10 cyclic sulfonate group and its derivatives, a C3-C10 cyclic sulfinate group and its derivatives, a C3-C10 cyclic carboxylate group and its derivatives, a C3-C10 cyclic carbonate group and its derivatives, or a C3-C10 cyclic phosphate group and its derivatives.

3. The non-aqueous electrolyte according to claim 1 or 2, characterized in that R1 is selected from ; wherein R7 and R8 are each independently selected from a C1~C5 alkylene group or a C1~C5 halogenated alkylene group; Y is selected from 、 、 、 、 、 、 or , among which R9, R 10 Each is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group.

4. The non-aqueous electrolyte according to claim 1 or 2, characterized in that R2 and R3 are each independently selected from , wherein R4 and R5 are each independently selected from a C1~C5 alkylene group or a C1~C5 halogenated alkylene group; X is selected from , wherein R6 are each independently selected from a hydrogen atom, a C1~C7 saturated hydrocarbon group, a C1~C7 hydrocarbonoxy group, a C1~C7 halogenated hydrocarbonoxy group, a C6~C7 aromatic hydrocarbon group, a C2~C7 unsaturated hydrocarbon group, a C1~C7 halogenated hydrocarbon group or a C1~C7 group containing a cyano group.

5. The non-aqueous electrolyte according to claim 1, characterized in that The compound represented by structural formula 1 is selected from one or more of the following compounds: 。 6. The non-aqueous electrolyte according to claim 1, characterized in that R1 is selected from C2~10 unsaturated hydrocarbon group or ; wherein R7 and R8 are each independently selected from a C1~C5 alkylene group or a C1~C5 halogenated alkylene group; Y is selected from 、 、 、 、 、 、 or , among which R9, R 10 Each is independently selected from a hydrogen atom, a C1-C7 saturated hydrocarbon group, a C1-C7 hydrocarbonoxy group, a C1-C7 halogenated hydrocarbonoxy group, a C6-C7 aromatic hydrocarbon group, a C2-C7 unsaturated hydrocarbon group, a C1-C7 halogenated hydrocarbon group or a C1-C7 group containing a cyano group; R2 and R3 are each independently selected from , wherein R4 and R5 are each independently selected from a C1~C5 alkylene group or a C1~C5 halogenated alkylene group; X is selected from , wherein R6 are each independently selected from a hydrogen atom, a C1~C7 saturated hydrocarbon group, a C1~C7 hydrocarbonoxy group, a C1~C7 halogenated hydrocarbonoxy group, a C6~C7 aromatic hydrocarbon group, a C2~C7 unsaturated hydrocarbon group, a C1~C7 halogenated hydrocarbon group or a C1~C7 group containing a cyano group.

7. The non-aqueous electrolyte according to claim 1, characterized in that ,, the compound represented by structural formula 1 is selected from one or more of the following compounds: 。 8. The non-aqueous electrolyte according to claim 1, wherein Based on the total mass of the non-aqueous electrolyte being 100%, the added amount of the compound represented by structural formula 1 is 0.05-10%.

9. The non-aqueous electrolyte according to claim 1, characterized in that The non-aqueous electrolyte further includes an auxiliary additive, and the auxiliary additive includes at least one of a cyclic sulfate compound, a sultone compound, a cyclic carbonate compound, an unsaturated phosphate compound, or a nitrile compound.

10. The non-aqueous electrolyte according to claim 9, characterized in that The cyclic sulfate compound is selected from at least one of vinyl sulfate, propylene sulfate or methyl vinyl sulfate; The sultone compound is selected from at least one of 1,3-propane sultone, 1,4-butane sultone or 1,3-propene sultone; The cyclic carbonate compound is selected from at least one of vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate or a compound represented by formula 2; Structural Formula 2 In the structural formula 2, R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each is independently selected from one of a hydrogen atom, a halogen atom and a C1-C5 group; The unsaturated phosphate compound is selected from at least one of the compounds shown in Structural Formula 3: Structural formula 3 In the structural formula 3, R 31 、R 32 、R 32 Each independently selected from C1-C5 saturated hydrocarbon group, unsaturated hydrocarbon group, halogenated hydrocarbon group, -Si(C m H 2m+1 )3, m is a natural number from 1 to 3, and R 31 、R 32 、R 33 At least one of them is an unsaturated hydrocarbon group; The nitrile compound includes one or more of succinonitrile, glutaronitrile, ethylene glycol bis(propionitrile) ether, hexanetrionitrile, adiponitrile, pimelonitrile, suberonitrile, azelaic acid dinitrile, and sebaconitrile.

11. The non-aqueous electrolyte according to claim 1, wherein The electrolyte salt is selected from LiPF6, LiBOB, LiDFOB, LiPO2F2, LiBF4, LiSbF6, LiAsF6, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, LiN(SO2F)2, LiClO4, LiAlCl4, LiCF3SO3, Li2B 10 Cl 10 , at least one of lower aliphatic carboxylic acid lithium salts.

12. The non-aqueous electrolyte according to claim 1, wherein The concentration of the electrolyte salt is 0.1 mol / L-8 mol / L.

13. A battery, characterized in that: The invention comprises a positive electrode, a negative electrode and the non-aqueous electrolyte according to any one of claims 1 to 12.

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