Non-aqueous electrolyte, lithium ion battery and electric equipment

Abstract

The invention provides a non-aqueous electrolyte, a lithium ion battery and electric equipment. The non-aqueous electrolyte comprises a first solvent, a second solvent, an electrolyte salt and an electrolyte additive, the electrolyte additive comprises one or more of Li < 3 + x > PO < 4-x > Nx, Li < 3y > La < 2 / 3-y > TiO3, Li < 7-z > La < 3 > Zr < 2-z > Ta < z > O12, Li < 1 + m > Al < m > Ti < 2-m > (PO4) 3 and Li < 1 + n > Al < n > Ge < 2-n > (PO4) 3, x is less than or equal to 0.5, 0lt; y is smaller than or equal to 0.16, 0 lt; z < = 0.5, 0lt; m is less than or equal to 0.5, 0lt; and n < = 0.5. According to the non-aqueous electrolyte, the second solvent with a specific structure is selected to be matched with the first solvent, and the appropriate electrolyte additive is added, so that the battery can have more excellent low-temperature performance.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of batteries, and particularly to a non-aqueous electrolyte, a lithium-ion battery, and an electrical device using the same. Background Art

[0002] Lithium-ion batteries are widely used in the field of new energy vehicles due to their excellent performance. However, at low temperatures, the performance of lithium-ion batteries will decline significantly, specifically manifested as extended charging time, reduced charge and discharge capacity, decreased battery capacity, and fast power consumption, which will affect the endurance of new energy vehicles and the user experience. This is mainly because at low temperatures, the transmission speed of lithium ions inside the battery decreases, the conductivity of the electrolyte decreases, and the battery impedance increases, resulting in a serious attenuation of the available energy and power of the battery. Summary of the Invention

[0003] In view of this, the embodiments of the present application provide a non-aqueous electrolyte. By selecting a second solvent with a specific structure to cooperate with the first solvent and adding one or more of electrolyte additives such as Li 3+x PO 4-x N x (LPON), Li 3y La 2 / 3-y TiO3(LLTO), Li 7- z La3Zr 2-z Ta z O 12 (LLZTO), Li 1+m Al m Ti 2-m (PO4)3(LATP), Li 1+n Al n Ge 2-n (PO4)3(LAGP), the battery can have better low-temperature performance.

[0004] The first aspect of the present application provides a non-aqueous electrolyte, which includes a first solvent, a second solvent, an electrolyte salt, and an electrolyte additive. The electrolyte additive includes Li 3+x PO 4-x N x , Li 3y La 2 / 3-y TiO3, Li 7- z La3Zr 2-z Ta z O 12 , Li 1+m Al m Ti 2-m (PO4)3, Li1+n Al n Ge 2-n (PO4)3, where 0 < x ≤ 0.5, 0 < y ≤ 0.16, 0 < z ≤ 0.5, 0 < m ≤ 0.5, 0 < n ≤ 0.5. The second solvent includes one or more of the compounds represented by Formula (I) to Formula (IV):

[0005]

[0006]

[0007] Wherein, R1 and R2 are each independently selected from any one of a halogen atom, a hydrogen atom, a C1-C3 hydrocarbon group, a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, and an alkyl carbonyl group, and at least one of R1 and R2 is a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, or an alkyl carbonyl group;

[0008] R3 is selected from a single bond, a C1-C3 hydrocarbon group, or a C1-C3 halogenated hydrocarbon group;

[0009] R4, R5, R6, R7, R8, and R 10 are each independently selected from any one of a C1-C3 hydrocarbon group, a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, and an alkyl carbonyl group, and at least one of R4 and R5 is a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, or an alkyl carbonyl group, at least one of R6 and R7 is a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, or an alkyl carbonyl group, and at least one of R8 and R 10 is a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, or an alkyl carbonyl group;

[0010] R9 is selected from a C1-C4 hydrocarbon group or a C1-C4 halogenated hydrocarbon group;

[0011] The first solvent includes one or more of carbonate solvents, carboxylate solvents, and ether solvents other than the compounds represented by Formula (I) to Formula (IV).

[0012] Optionally, the particle size D50 of the electrolyte additive is 10 nm - 300 nm.

[0013] Optionally, the mass percentage content of the electrolyte additive in the non-aqueous electrolyte is 0.1% - 10%.

[0014] Optionally, the mass percentage content of the second solvent in the non-aqueous electrolyte is 2% - 60%.

[0015] Optionally, the mass ratio of the first solvent to the second solvent is 0.16 - 45:1.

[0016] Optionally, the mass ratio of the second solvent to the electrolyte additive is 0.2 - 600:1.

[0017] Optionally, the mass ratio of the second solvent to the electrolyte additive is 0.4 - 40:1.

[0018] Optionally, the second solvent is selected from one or more of the compounds represented by Formula (1) to Formula (20):

[0019]

[0020]

[0021] Optionally, the carbonate solvents include one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate; the carboxylate solvents include one or more of methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, and butyl butyrate; the ether solvents include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, 1,3 - dioxolane, dimethoxymethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, isosorbide dimethyl ether, dipropylene glycol dimethyl ether, 1,1,2,2 - tetrafluoroethyl ethyl ether, 1,1,2,3,3,3 - pentafluoropropyl - 2,2,2 - trifluoroethyl ether, 1,1,2,2 - tetrafluoroethyl - 2,2,3,3 - tetrafluoropropyl ether, 1,1,2,2 - tetrafluoroethyl - 2,2,2 - trifluoroethyl ether, 2,2,3,3 - tetrafluoropropyl dimethyl ether, 1,1,1,3,3,3 - hexafluoroisopropyl methyl ether, and 2,2,2 - trifluoroethyl ether.

[0022] Optionally, the non - aqueous electrolyte further includes an electrolyte salt, and the electrolyte salt includes one or more of LiPF6, LiBF4, LiBOB, LiDFOB, LiDFOP, LiPO2F2, LiSbF6, LiAsF6, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, and LiN(SO2F)2.

[0023] Optionally, the non - aqueous electrolyte further includes one or more of 1,3 - propane sultone, 1,3 - propene sultone, 1,4 - butane sultone, vinylene carbonate, fluoroethylene carbonate, methylene methanedisulfonate, and vinylene sulfate.

[0024] The second aspect of the present application further provides a lithium-ion battery, which includes an electrolyte solution, and the electrolyte solution includes the non-aqueous electrolyte solution provided in the first aspect of the present application.

[0025] The third aspect of the present application further provides an electrical device, which includes the lithium-ion battery provided in the second aspect of the present application. Using the lithium-ion battery provided in the present application to supply power to the device can effectively improve the endurance and safety performance of the electrical device in a low-temperature environment, and enhance its market competitiveness. Description of the Drawings

[0026] Figure 1 It is a schematic structural diagram of a lithium-ion battery provided in an embodiment of the present application.

[0027] Description of the Reference Numerals in the Drawings

[0028] 100 - Lithium-ion battery; 101 - Non-aqueous electrolyte solution; 102 - Separator; 103 - Positive electrode plate; 104 - Negative electrode plate; 105 - Battery case. Detailed Embodiments

[0029] The following further describes the present application in detail with reference to preferred embodiments, but the protection scope of the present application is not limited to the following specific embodiments.

[0030] In the present application, all technical terms have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and do not limit the protection scope of the present application.

[0031] Lithium-ion batteries are widely used in the new energy vehicle field due to their excellent performance. Under low-temperature conditions, the performance of lithium-ion batteries will significantly decline, specifically manifested as extended charging time, reduced charge and discharge capacity, smaller battery capacity, fast power loss, etc., which will further affect the endurance of new energy vehicles and the user experience.

[0032] In a low-temperature environment, the available energy and power characteristics of lithium-ion batteries decay relatively seriously. When the battery is under too low temperature conditions, the viscosity of the electrolyte solution is relatively large, the movement of lithium ions is blocked, the transmission speed of lithium ions slows down, and the insertion and extraction of lithium ions on the surface of the negative electrode lose balance, resulting in the deposition of some lithium ions on the surface of the negative electrode, causing lithium plating phenomenon and resulting in battery capacity loss.

[0033] To solve the above technical problems, an embodiment of the present application provides a non-aqueous electrolyte solution, which includes a first solvent, a second solvent, and an electrolyte additive, and the electrolyte additive includes Li 3+x PO 4-x N x 、Li 3y La 2 / 3-y TiO3、Li7-z La3Zr 2- z Ta z O 12 、Li 1+m Al m Ti 2-m (PO4)3, Li 1+n Al n Ge 2-n One or more of (PO4)3, where 0 < x ≤ 0.5, 0 < y ≤ 0.16, 0 < z ≤ 0.5, 0 < m ≤ 0.5, 0 < n ≤ 0.5. The second solvent includes one or more of the compounds shown in formulas (I) to (IV):

[0034]

[0035] Wherein, R1 and R2 are each independently selected from any one of a halogen atom, a hydrogen atom, a C1-C3 hydrocarbon group, a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, and an alkyl carbonyl group, and at least one of R1 and R2 is a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, or an alkyl carbonyl group;

[0036] R3 is selected from a single bond, a C1-C3 hydrocarbon group, or a C1-C3 halogenated hydrocarbon group;

[0037] R4, R5, R6, R7, R8, and R 10 Are each independently selected from any one of a C1-C3 hydrocarbon group, a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, and an alkyl carbonyl group, and at least one of R4 and R5 is a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, or an alkyl carbonyl group, at least one of R6 and R7 is a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, or an alkyl carbonyl group, and at least one of R8 and R 10 Is a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, or an alkyl carbonyl group;

[0038] R9 is selected from a C1-C4 hydrocarbon group or a C1-C4 halogenated hydrocarbon group;

[0039] The first solvent includes one or more of carbonate solvents, carboxylate solvents, and ether solvents other than the compounds shown in formulas (I) to (IV).

[0040] In the embodiments of the present application, the number of carbon atoms of the C1-C3 hydrocarbon group can be 1, 2, or 3. The C1-C3 hydrocarbon group can be a C1-C3 alkyl group, a C1-C3 alkenyl group, or a C1-C3 alkynyl group. In some specific embodiments of the present application, the C1-C3 hydrocarbon group can be, for example, a methyl group, an ethyl group, a n-propyl group, or an isopropyl group.

[0041] In the embodiments of the present application, the number of carbon atoms of the C1-C3 haloalkyl group can be 1, 2, or 3. The halogen atom in the C1-C3 haloalkyl group can be, for example, a fluorine atom, a chlorine atom, or a bromine atom. The C1-C3 haloalkyl group can be fluoromethyl, fluoroethyl, or fluoropropyl. In some specific embodiments of the present application, the C1-C3 haloalkyl group can be, for example, monofluoromethyl, difluoromethyl, trifluoromethyl, difluoroethyl, trifluoroethyl, tetrafluoroethyl, or tetrafluoropropyl.

[0042] In the embodiments of the present application, R9 is selected from a C1-C4 hydrocarbon group or a C1-C4 haloalkyl group. The number of carbon atoms of the C1-C4 hydrocarbon group can be 1, 2, 3, or 4, and the number of carbon atoms of the C1-C4 haloalkyl group can be 1, 2, 3, or 4. The halogen atom in the C1-C4 haloalkyl group can be, for example, a fluorine atom, a chlorine atom, or a bromine atom.

[0043] In the embodiments of the present application, R1 and R2 can be the same or different groups. For example, R1 can be a fluorine atom and R2 can be a hydrogen atom; or, both R1 and R2 can be fluorine atoms. R4 and R5 can be the same or different groups. For example, R4 can be a methyl group and R5 can be a trifluoroethyl group; or, both R4 and R5 can be trifluoroethyl groups. R6 and R7 can be the same or different groups. For example, R6 can be a methyl group and R7 can be a trifluoromethyl group; or, both R6 and R7 can be trifluoromethyl groups. R8 and R 10 can be the same or different groups. For example, R8 can be a methyl group and R 10 can be difluoromethyl; or, both R8 and R 10 can be difluoromethyl.

[0044] The non-aqueous electrolyte of the embodiment of the present application, wherein the second solvent is obtained by substituting atoms or groups in common electrolyte solvents with electron-withdrawing atoms or groups. Affected by the electron-withdrawing inductive effect of the electron-withdrawing atoms or groups, the electron cloud density of the oxygen atoms in the molecular structure of the second solvent decreases, thereby reducing the binding force between the electrolyte solvent and lithium ions, making it easier for lithium ions to be desolvated, and thus improving the transport rate of lithium ions and enhancing the rate performance of the battery under low-temperature conditions. In addition, the inventors of the present application found that although the addition of the second solvent can better improve the desolvation ability of lithium ions and enhance the lithium ion transport ability, to a certain extent, it will exacerbate the reduction side reaction at the negative electrode, consume the electrolyte, increase the impedance at the interface between the electrolyte and the negative electrode, and may also cause the solubility of the electrolyte salt in the electrolyte to decrease, resulting in a decrease in the conductivity and an increase in the viscosity of the electrolyte, thereby affecting the electrochemical performance of the battery. Therefore, in the present application, by adding an electrolyte additive and the second solvent simultaneously and using their mutual cooperation, the low-temperature performance of the battery is jointly improved. The electrolyte additive described above in the present application can reduce and generate SEI film components such as Li3PO4 and Li2O on the surface of the negative electrode active material, effectively inhibiting the reduction side reaction at the negative electrode interface caused by the excessive second solvent, thereby effectively avoiding the increase in impedance brought by the second solvent. In addition, the electrolyte additive can also effectively reduce the freezing point of the electrolyte, enhance the dissociation of the electrolyte salt in the electrolyte and ion transport under low-temperature conditions, thereby avoiding problems such as a decrease in the conductivity and an increase in the viscosity of the electrolyte caused by the excessive second solvent. That is to say, the second solvent plays a role in improving the desolvation of lithium ions in the electrolyte. While the electrolyte additive improves the desolvation effect, it avoids problems such as an increase in impedance and a decrease in conductivity brought by the second solvent. The two work synergistically, making the desolvation of lithium ions in the electrolyte significantly faster, the SEI film impedance smaller and more stable, and the low-temperature performance of the battery significantly improved.

[0045] In some embodiments of the present application, the second solvent can be, for example, one or more of the compounds represented by formulas (1) to (20):

[0046]

[0047]

[0048] In some embodiments of the present application, when the second solvent is selected from one or more of the compounds represented by the above formulas (1)-(20), the improvement effect on the low-temperature performance of the electrolyte is more significant.

[0049] In the embodiment of the present application, the electrolyte additive includes Li 3+x PO 4-x N x 、Li 3y La 2 / 3-yTiO3, Li 7-z La3Zr 2- z Ta z O 12 、Li 1+m Al m Ti 2-m (PO4)3, Li 1+n Al n Ge 2-n (PO4)3, wherein 0 < x ≤ 0.5, 0 < y ≤ 0.16, 0 < z ≤ 0.5, 0 < m ≤ 0.5, 0 < n ≤ 0.5. In this application, a nano-sized electrolyte additive is added to a conventional liquid electrolyte to form a solid-liquid mixed non-aqueous electrolyte. On the one hand, electrolyte additives such as LPON, LLTO, LLZTO, LATP, and LAGP can effectively lower the freezing point of the liquid electrolyte, thereby enhancing the dissociation of lithium salts and ion transport in the electrolyte under low-temperature conditions. On the other hand, electrolyte additives such as LATP will also reduce and generate solid electrolyte interface (SEI) film components such as Li3PO4 and Li2O on the surface of the negative active material, thereby enhancing the ionic conductivity, significantly reducing the battery impedance, especially suppressing the increase in battery impedance under low-temperature conditions, improving the capacity retention rate of lithium-ion batteries during low-temperature discharge, and thus enhancing the endurance of lithium-ion batteries in low-temperature environments.

[0050] In the embodiments of this application, the electrolyte additive Li 3+x PO 4-x N x is LPON, wherein 0 < x ≤ 0.5 refers to a lithium phosphorus oxygen nitrogen solid electrolyte; Li 3y La 2 / 3-y TiO3 is LLTO, wherein 0 < y ≤ 0.16 refers to a lithium lanthanum titanium oxygen solid electrolyte; Li 7-z La3Zr 2- z Ta z O 12 is LLZTO, wherein 0 < z ≤ 0.5 refers to a lithium lanthanum zirconium tantalum oxygen solid electrolyte; Li 1+m Al m Ti 2-m (PO4)3 is LATP, wherein 0 < m ≤ 0.5 refers to a lithium aluminum titanium phosphate solid electrolyte; Li 1+n Al n Ge 2-n (PO4)3 is LAGP, wherein 0 < n ≤ 0.5 refers to a lithium aluminum germanium phosphate solid electrolyte.

[0051] In the embodiment of the present application, the particle size D50 of the electrolyte additive is 10nm-300nm. Exemplarily, the particle size D50 of the electrolyte additive can be 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 50nm, 55nm, 60nm, 70nm, 75nm, 80nm, 90nm, 100nm, 125nm, 150nm, 175nm, 200nm, 225nm, 250nm, 275nm, 300nm. By controlling the particle size of the electrolyte additive within the above-mentioned nanoscale range, while ensuring that the electrolyte additive has good dispersibility in the non-aqueous electrolyte, it has a larger specific surface area and better contacts with the positive and negative active materials. On the one hand, it helps the transmission of lithium ions in the electrolyte, and on the other hand, it can also increase the liquid retention capacity of the active material, effectively reduce the low-temperature DC resistance of the full battery, and thus improve the low-temperature performance of the lithium-ion battery. In addition, the solvated ions in the electrolyte are acted upon by the surface of the electrolyte additive particles such as the nanoscale LATP of the present application, and the electrolyte additive plays a role of pre-desolvation, thereby reducing the desolvation energy barrier of the solvated ions at the interface between the negative electrode active material and the electrolyte, accelerating the desolvation reaction, and improving the stability of lithium deposition / stripping, thereby improving the battery capacity and cycle performance of the battery at low temperatures.

[0052] In some embodiments of the present application, the mass percentage of the electrolyte additive in the non-aqueous electrolyte is 0.1%-10%. Exemplarily, the mass percentage of the electrolyte additive in the non-aqueous electrolyte can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.8%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. Controlling the content of the electrolyte additive within the above range can ensure that the electrolyte additive plays a certain role in improving the low-temperature performance of the battery while avoiding sedimentation as much as possible, further reducing the impedance of the electrolyte and the negative electrode interface.

[0053] In some embodiments of the present application, the mass percentage of the second solvent in the non-aqueous electrolyte is 2%-60%. Exemplarily, the mass percentage of the second solvent in the non-aqueous electrolyte can be 2%, 3%, 4%, 5%, 7%, 8%, 10%, 15%, 19%, 20%, 25%, 30%, 31%, 35%, 40%, 45%, 50%, 55%, 60%. Controlling the content of the second solvent within the above range can make it easier for lithium ions to desolvate, further improve the transmission rate of lithium ions, and enhance the rate performance of the battery under low temperature conditions.

[0054] In some embodiments of the present application, the mass ratio of the first solvent to the second solvent is 0.16 - 45:1. Exemplarily, the mass ratio of the first solvent to the second solvent can be 0.16:1, 0.2:1, 0.5:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 8:1, 9:1, 10:1, 15:1, 20:1, 24:1, 25:1, 30:1, 35:1, 40:1, 45:1. By reasonably regulating the ratio between the first solvent and the second solvent, the present application can enable the first solvent and the second solvent to better play a synergistic role together, which is more conducive to the dispersion of the electrolyte additive in the non-aqueous electrolyte and further improves the low-temperature performance of the battery.

[0055] In some embodiments of the present application, the mass ratio of the second solvent to the electrolyte additive is 0.2 - 600:1. Exemplarily, the mass ratio of the second solvent to the electrolyte additive can be 0.2:1, 0.3:1, 0.5:1, 0.8:1, 1:1, 2:1, 5:1, 10:1, 20:1, 30:1, 50:1, 80:1, 100:1, 120:1, 150:1, 180:1, 200:1, 250:1, 300:1, 350:1, 400:1, 450:1, 500:1, 550:1, 600:1. By reasonably regulating the ratio between the second solvent and the electrolyte additive, the present application can enable the second solvent and the electrolyte additive to better play a synergistic role together, significantly accelerating the desolvation of lithium ions in the electrolyte, making the SEI film impedance smaller and more stable, and improving the low-temperature performance of the battery.

[0056] In some embodiments of the present application, the mass ratio of the second solvent to the electrolyte additive is 0.4 - 40:1. Exemplarily, the mass ratio of the second solvent to the electrolyte additive can be 0.4:1, 0.5:1, 0.8:1, 1:1, 2:1, 5:1, 10:1, 20:1, 30:1, 40:1. Controlling the mass ratio of the second solvent to the electrolyte additive within the above range can further accelerate the desolvation of lithium ions in the electrolyte, better play the synergistic role between the second solvent and the electrolyte additive, make the battery more stable, and better improve the low-temperature performance of the battery.

[0057] In some embodiments of the present application, the first solvent includes one or more of carbonate solvents, carboxylate solvents, and ether solvents. Among them, the carbonate solvents include one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate; the carboxylate solvents include one or more of methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, and butyl butyrate; the ether solvents include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, 1,3-dioxolane, dimethoxymethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, isosorbide dimethyl ether, dipropylene glycol dimethyl ether, 1,1,2,2-tetrafluoroethyl ethyl ether, 1,1,2,3,3,3-pentafluoropropyl-2,2,2-trifluoroethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 2,2,3,3-tetrafluoropropyl dimethyl ether, 1,1,1,3,3,3-hexafluoroisopropyl methyl ether, and 2,2,2-trifluoroethyl ether. Selecting the above solvents as the solvents of the non-aqueous electrolyte of the present application can further promote the dissolution of the electrolyte salt in the non-aqueous electrolyte, further promote the ion migration in the non-aqueous electrolyte, and thus improve the electrochemical performance of the battery.

[0058] In some embodiments of the present application, the non-aqueous electrolyte further includes an electrolyte salt, and the electrolyte salt includes one or more of LiPF6, LiBF4, LiBOB, LiDFOB, LiDFOP, LiPO2F2, LiSbF6, LiAsF6, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, and LiN(SO2F)2. Through the coordinated selection of the electrolyte salt and the solvent in the present application, the solubility of the electrolyte salt in the solvent is made as large as possible. By selecting a suitable electrolyte salt and controlling the addition amount of the above electrolyte salt within a suitable range, a high conductivity can be provided for the electrolyte solution, and electrolyte salts such as LiPF6 can form an appropriate SEI film on the negative electrode and effectively passivate the positive electrode, further improving the electrochemical performance of the battery.

[0059] In some specific embodiments of the present application, the non-aqueous electrolyte further includes other additives, including one or more of 1,3-propane sultone, 1,3-propene sultone, 1,4-butane sultone, vinylene carbonate, fluoroethylene carbonate, methylene methanedisulfonate, and ethylene sulfate. By adding the above additives, overcharging of the battery can be effectively prevented, the performance of the SEI film can be improved, the protection effect of the positive electrode can be enhanced, and the comprehensive performance of the battery can be further improved.

[0060] The non-aqueous electrolyte provided by the present application is prepared by combining a second solvent with a specific structure with a first solvent and adding electrolyte additives such as LPON, LLTO, LLZTO, LATP, and LAGP. This method has a simple process and can effectively reduce the battery impedance at low temperatures and improve the ion transport rate, thereby improving the low-temperature performance of the lithium-ion battery.

[0061] The present application also provides a lithium-ion battery, including a battery case and a positive electrode, a negative electrode, a separator, and an electrolyte accommodated inside the battery case. The separator is disposed between the positive electrode and the negative electrode, and the electrolyte is the non-aqueous electrolyte provided in the foregoing of the present application. The lithium-ion battery includes, but is not limited to, a wound lithium-ion battery and a laminated lithium-ion battery. The positive electrode and the negative electrode in the lithium-ion battery can be a group or multiple groups. In some specific embodiments of the present application, the lithium-ion battery 100 is Figure 1 As shown, the lithium-ion battery 100 is a laminated battery, including a battery case 105 and a non-aqueous electrolyte 101, a separator 102, a positive electrode plate 103, and a negative electrode plate 104 accommodated inside the battery case 105. The positive electrode plate 103 and the negative electrode plate 104 are stacked in sequence. The separator 102 is folded in a "Z" shape to separate the positive electrode plate 103 and the negative electrode plate 104. In order to facilitate better insertion and extraction of lithium ions, the outermost sides of the lithium-ion battery are both negative electrode plates 104, that is, the number of negative electrode plates 104 is one more than that of positive electrode plates 103. Among them, the non-aqueous electrolyte 101 is the non-aqueous electrolyte described in the foregoing of the present application; the separator 102 is a polymer thin film; the positive electrode plate 103 includes a positive electrode current collector and a positive electrode active layer provided on the positive electrode current collector; the negative electrode plate 104 includes a negative electrode current collector and a negative electrode active layer provided on the negative electrode current collector; the battery case 105 includes, but is not limited to, materials such as a steel case, an aluminum case, a nickel-plated iron case, or an aluminum plastic film. The lithium-ion battery provided by the embodiment of the present application uses the non-aqueous electrolyte described above, and the lithium-ion battery has good cycle performance and a large battery capacity in a low-temperature environment.

[0062] In the embodiments of the present application, the positive electrode active material in the positive electrode material layer can be any positive electrode active material known in the art for lithium-ion batteries. Exemplarily, in some embodiments, the positive electrode sheet includes a positive electrode current collector and a positive electrode material layer stacked on the surface of the positive electrode current collector. The positive electrode material layer includes a positive electrode active material, and the positive electrode active material includes at least one of a phosphate-based positive electrode active material and a transition metal oxide positive electrode active material. Among them, the phosphate-based positive electrode active material includes, but is not limited to, one or more of doped or undoped lithium iron phosphate, lithium manganese iron phosphate and other materials, and the transition metal oxide positive electrode active material includes, but is not limited to, one or more of doped or undoped ternary materials, lithium-rich layered oxides and other materials.

[0063] In the embodiments of the present application, the negative electrode active material in the negative electrode material layer can be any negative electrode active material known in the art for lithium-ion batteries. Exemplarily, the negative electrode active material can be selected from one or more of carbon-based negative electrode active materials, silicon-based negative electrode active materials, tin-based negative electrode active materials, and lithium metal negative electrode active materials. Among them, the carbon-based negative electrode can include natural graphite, artificial graphite, hard carbon, soft carbon, graphene, etc.; the silicon-based negative electrode can include silicon, silicon carbide, silicon oxide, etc.; the tin-based negative electrode can include tin, tin carbide, tin oxide, tin metal compounds, but is not limited thereto.

[0064] The present application also provides an electrical device, which includes the lithium-ion battery described above. The electrical device can be, for example, an electric vehicle, a mobile phone, a tablet computer, a laptop computer, a wearable device (watch, bracelet), a digital camera, etc. The electrical device is powered by the lithium-ion battery described above, has good low-temperature performance, good cruising ability in a low-temperature environment, and greatly improves the user experience and market competitiveness.

[0065] The technical solution of the present application will be described in detail in the following multiple embodiments.

[0066] Example 1

[0067] Prepare a non-aqueous electrolyte: Mix ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate and the compound shown in formula (1) in a mass ratio of 0.3:0.3:0.3:0.1 to obtain a mixed solvent, then add 1 mol / L lithium hexafluorophosphate, and then add 3% of the electrolyte additive of LATP based on the total mass of the non-aqueous electrolyte to obtain a non-aqueous electrolyte.

[0068] Prepare a positive electrode: Mix the positive electrode active material lithium iron phosphate, the conductive agent carbon nanotubes and the binder polyvinylidene fluoride in a mass ratio of 95.8:1.7:2.5, and then disperse them in N-methyl-2-pyrrolidone (NMP) to obtain a positive electrode slurry. Coat the positive electrode slurry evenly on both sides of the aluminum foil, dry, calender and vacuum dry it, and then weld an aluminum tab with an ultrasonic welder to obtain a positive electrode.

[0069] Preparation of the negative electrode: Artificial graphite as the negative electrode active material, carbon nanotubes as the conductive agent, polyacrylic acid as the binder, and carboxymethyl cellulose as the thickening agent with a mass ratio of 94.2:1.1:4.7:0.5 were mixed, and then they were dispersed in deionized water to obtain a negative electrode slurry. The negative electrode slurry was coated on both sides of the copper foil, dried, rolled, and vacuum dried, and a nickel tab was welded with an ultrasonic welder to obtain the negative electrode.

[0070] Preparation of the lithium-ion battery: The separator was folded in a "Z" shape, and then the positive and negative electrodes were inserted alternately, ensuring that the outermost layers were two negative electrodes. Usually, 7 positive electrodes and 8 negative electrodes were used. After the core package was folded, it was fixed with a high-temperature tape, and then the core package was placed in an aluminum foil packaging bag and vacuum baked at 85 °C for 48 h to obtain a battery cell to be filled with electrolyte; in a drying room with the dew point controlled below -40 °C, the electrolyte prepared above was injected into the battery cell, vacuum packaged, and left standing at 45 °C for 24 h. Then, the following steps were carried out for the conventional formation of the first charge: constant current charging at 0.05C for 120 min, constant current charging at 0.2C for 240 min, standing at 45 °C for 36 h, secondary vacuum sealing, and then constant current and constant voltage charging at a current of 0.2C until 3.8V. After standing at room temperature for 24 h, constant current discharging at a current of 0.2C until 3.0V, and then cycling 2 times at a current of 0.2C to complete the capacity grading, obtaining the lithium-ion battery.

[0071] Example 2

[0072] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, and the compound shown in formula (8) with a mass ratio of 0.3:0.3:0.3:0.1.

[0073] Example 3

[0074] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, and the compound shown in formula (12) with a mass ratio of 0.3:0.3:0.3:0.1.

[0075] Example 4

[0076] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, and the compound shown in formula (18) with a mass ratio of 0.3:0.3:0.3:0.1.

[0077] Example 5

[0078] The difference from Example 1 is that the electrolyte additive is 3% of LLZTO based on the total mass of the non-aqueous electrolyte.

[0079] Example 6

[0080] The difference from Example 2 is that the electrolyte additive is 3% of LLZTO based on the total mass of the non-aqueous electrolyte.

[0081] Example 7

[0082] The difference from Example 3 is that the electrolyte additive is 3% of LLZTO based on the total mass of the non-aqueous electrolyte.

[0083] Example 8

[0084] The difference from Example 4 is that the electrolyte additive is 3% of LLZTO based on the total mass of the non-aqueous electrolyte.

[0085] Example 9

[0086] The difference from Example 1 is that the electrolyte additive is 3% of LLTO based on the total mass of the non-aqueous electrolyte.

[0087] Example 10

[0088] The difference from Example 2 is that the electrolyte additive is 3% of LLTO based on the total mass of the non-aqueous electrolyte.

[0089] Example 11

[0090] The difference from Example 3 is that the electrolyte additive is 3% of LLTO based on the total mass of the non-aqueous electrolyte.

[0091] Example 12

[0092] The difference from Example 4 is that the electrolyte additive is 3% of LLTO based on the total mass of the non-aqueous electrolyte.

[0093] Example 13

[0094] The difference from Example 1 is that the positive electrode active material is LiNi 0.6 Mn 0.2 Co 0.2 O2 (NCM622).

[0095] Example 14

[0096] The difference from Example 1 is that the positive electrode active material is LiNi 0.6 Mn 0.2 Co 0.2 O2 (NCM622), and the negative electrode active material is silicon carbide.

[0097] Example 15

[0098] The difference from Example 1 is that the electrolyte additive is 0.1% of LATP based on the total mass of the non-aqueous electrolyte.

[0099] Example 16

[0100] The difference from Example 1 is that the electrolyte additive is 1% of LATP based on the total mass of the non-aqueous electrolyte.

[0101] Example 17

[0102] The difference from Example 1 is that the electrolyte additive is 2% of LATP based on the total mass of the non-aqueous electrolyte.

[0103] Example 18

[0104] The difference from Example 1 is that the electrolyte additive is 5% of LATP based on the total mass of the non-aqueous electrolyte.

[0105] Example 19

[0106] The difference from Example 1 is that the electrolyte additive is 7% of LATP based on the total mass of the non-aqueous electrolyte.

[0107] Example 20

[0108] The difference from Example 1 is that the electrolyte additive is 10% of LATP based on the total mass of the non-aqueous electrolyte.

[0109] Example 21

[0110] The difference from Example 1 is that the non-aqueous electrolyte further includes 3% of vinylene carbonate (VC) based on the total mass of the non-aqueous electrolyte.

[0111] Example 22

[0112] The difference from Example 1 is that the non-aqueous electrolyte further includes 3% of fluoroethylene carbonate (FEC) based on the total mass of the non-aqueous electrolyte.

[0113] Example 23

[0114] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate and the compound shown in formula (1) with a mass ratio of 0.33:0.33:0.33:0.01.

[0115] Example 24

[0116] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate and the compound shown in formula (1) with a mass ratio of 0.32:0.32:0.32:0.04.

[0117] Example 25

[0118] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, and the compound shown in formula (1) with a mass ratio of 0.27:0.27:0.27:0.19.

[0119] Example 26

[0120] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, and the compound shown in formula (1) with a mass ratio of 0.23:0.23:0.23:0.31.

[0121] Example 27

[0122] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, and the compound shown in formula (1) with a mass ratio of 0.2:0.2:0.2:0.4.

[0123] Example 28

[0124] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, and the compound shown in formula (1) with a mass ratio of 0.15:0.15:0.15:0.55.

[0125] Example 29

[0126] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, the compound shown in formula (1), and the compound shown in formula (8) with a mass ratio of 0.3:0.3:0.3:0.05:0.05.

[0127] Example 30

[0128] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, the compound shown in formula (1), and the compound shown in formula (18) with a mass ratio of 0.3:0.3:0.3:0.05:0.05.

[0129] Example 31

[0130] The difference from Example 1 is that the electrolyte additive is 1.5% of LLZTO and 1.5% of LATP based on the total mass of the non-aqueous electrolyte.

[0131] Example 32

[0132] The difference from Example 1 is that the electrolyte additive is 1.5% of LLTO and 1.5% of LATP based on the total mass of the non-aqueous electrolyte.

[0133] Example 33

[0134] The difference from Example 1 is that the electrolyte additive is 1.5% LPON and 1.5% LATP based on the total mass of the non-aqueous electrolyte.

[0135] Example 34

[0136] The difference from Example 1 is that the electrolyte additive is 1.5% LAGP and 1.5% LATP based on the total mass of the non-aqueous electrolyte.

[0137] Example 35

[0138] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate and the compound shown in formula (5) with a mass ratio of 0.27:0.27:0.27:0.19.

[0139] Example 36

[0140] The difference from Example 1 is that the mixed solvent is ethylene carbonate, ethyl methyl carbonate, dimethyl carbonate and the compound shown in formula (13) with a mass ratio of 0.27:0.27:0.27:0.19.

[0141] To highlight the beneficial effects of the embodiments of the present application, the following comparative examples are set.

[0142] Comparative Example 1

[0143] Prepare a non-aqueous electrolyte: Mix ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate with a mass ratio of 1:1:1 to obtain a mixed solvent, then add 1 mol / L lithium hexafluorophosphate, and then add an electrolyte additive of 0.1% LATP based on the total mass of the non-aqueous electrolyte to obtain a non-aqueous electrolyte.

[0144] Prepare a positive electrode: Mix the positive electrode active material lithium iron phosphate, conductive agent carbon nanotubes and binder polyvinylidene fluoride with a mass ratio of 95.8:1.7:2.5, and then disperse them in N-methyl-2-pyrrolidone (NMP) to obtain a positive electrode slurry. Coat the positive electrode slurry evenly on both sides of the aluminum foil, dry, calender and vacuum dry it, and weld an aluminum pole ear with an ultrasonic welder to obtain a positive electrode.

[0145] Prepare a negative electrode: Mix the negative electrode active material artificial graphite, conductive agent carbon nanotubes, binder polyacrylic acid and thickener carboxymethyl cellulose with a mass ratio of 94.2:1.1:4.7:0.5, and then disperse them in deionized water to obtain a negative electrode slurry. Coat the negative electrode slurry on both sides of the copper foil, dry, calender and vacuum dry it, and weld a nickel pole ear with an ultrasonic welder to obtain a negative electrode.

[0146] Preparation of lithium-ion battery: The separator is folded in a "Z" shape, and then the positive and negative electrodes are inserted alternately, ensuring that the two outermost layers are negative electrodes. Usually, 7 positive electrodes and 8 negative electrodes are used. After the core package is folded, it is fixed with high-temperature tape, and then the core package is placed in an aluminum foil packaging bag and vacuum baked at 85°C for 48 hours to obtain the cell to be filled with electrolyte. In a drying room with the dew point controlled below -40°C, the electrolyte prepared above is injected into the cell, and after vacuum packaging, it is left standing at 45°C for 24 hours. Then, the following steps are carried out for the conventional formation of the first charge: constant current charging at 0.05C for 120 minutes, constant current charging at 0.2C for 240 minutes, standing at 45°C for 36 hours, secondary vacuum sealing, and then constant current and constant voltage charging at a current of 0.2C until 3.8V. After standing at room temperature for 24 hours, constant current discharging at a current of 0.2C until 3.0V, and then cycling 2 times at a current of 0.2C to complete the capacity grading, obtaining the lithium-ion battery.

[0147] Comparative Example 2

[0148] The difference from Comparative Example 1 is that the electrolyte additive is 1% of LATP based on the total mass of the non-aqueous electrolyte.

[0149] Comparative Example 3

[0150] The difference from Comparative Example 1 is that the electrolyte additive is 2% of LATP based on the total mass of the non-aqueous electrolyte.

[0151] Comparative Example 4

[0152] The difference from Comparative Example 1 is that the electrolyte additive is 3% of LATP based on the total mass of the non-aqueous electrolyte.

[0153] Comparative Example 5

[0154] The difference from Comparative Example 1 is that the electrolyte additive is 5% of LATP based on the total mass of the non-aqueous electrolyte.

[0155] Comparative Example 6

[0156] The difference from Comparative Example 1 is that the electrolyte additive is 7% of LATP based on the total mass of the non-aqueous electrolyte.

[0157] Comparative Example 7

[0158] The difference from Comparative Example 1 is that the electrolyte additive is 10% of LATP based on the total mass of the non-aqueous electrolyte.

[0159] Comparative Example 8

[0160] The difference from Comparative Example 1 is that no electrolyte additive is added.

[0161] Comparative Example 9

[0162] The difference from Example 1 is that no electrolyte additive is added.

[0163] Comparative Example 10

[0164] The difference from Example 2 is that no electrolyte additive is added.

[0165] Comparative Example 11

[0166] The difference from Example 3 is that no electrolyte additive is added.

[0167] Comparative Example 12

[0168] The difference from Example 4 is that no electrolyte additive is added.

[0169] Comparative Example 13

[0170] The difference from Comparative Example 4 is that the positive electrode active material is LiNi 0.6 Mn 0.2 Co 0.2 O2 (NCM622).

[0171] Comparative Example 14

[0172] The difference from Comparative Example 9 is that the positive electrode active material is LiNi 0.6 Mn 0.2 Co 0.2 O2 (NCM622).

[0173] Comparative Example 15

[0174] The difference from Comparative Example 8 is that the positive electrode active material is LiNi 0.6 Mn 0.2 Co 0.2 O2 (NCM622).

[0175] Comparative Example 16

[0176] The difference from Comparative Example 4 is that the negative electrode active material is silicon carbon.

[0177] Comparative Example 17

[0178] The difference from Comparative Example 9 is that the negative electrode active material is silicon carbon.

[0179] Comparative Example 18

[0180] The difference from Comparative Example 8 is that the negative electrode active material is silicon carbon.

[0181] Performance Test

[0182] (1) Low-temperature DCIR (Direct Current Resistance) Test:

[0183] The lithium-ion batteries of each example and comparative example were fixed to 50% SOC (capacity reference: rated capacity in the constant volume stage) at 25 °C, then placed in a high and low temperature chamber at -20 °C, and left to stand for more than 8 hours to ensure that the battery body temperature was stable at -20 °C. Subsequently, it was discharged for 30 s at a current value of 1.5C. The calculation formula for the discharge DC resistance is: Discharge DCIR = (pre-discharge voltage value - post-discharge voltage value) / discharge current value * 1000 (the units of voltage and current are volts V and amperes A respectively), and the calculation results are summarized in Table 1.

[0184] (2) Low-temperature capacity retention test:

[0185] The lithium-ion batteries of each example and comparative example were fixed to 100% SOC (capacity reference: rated capacity in the constant volume stage) at 25 °C, then placed in a high and low temperature chamber at -20 °C, and left to stand for more than 8 h to ensure that the battery body temperature was stable at -20 °C. Subsequently, it was discharged to 2.0 V at a current value of 0.33C. The calculation formula for the low-temperature capacity retention is: Low-temperature capacity retention = 0.33C discharge capacity (-20 °C) / 0.33C discharge capacity (25 °C) * 100%, and the calculation results are summarized in Table 1.

[0186] Table 1

[0187]

[0188]

[0189]

[0190] It can be found from the data in Table 1 that compared with the comparative examples that only added the second solvent without adding electrolyte additives and only added electrolyte additives without adding the second solvent, the low-temperature DC resistance of the lithium-ion batteries obtained from the non-aqueous electrolyte that commonly added electrolyte additives and the second electrolyte provided in the examples of this application was significantly reduced, and the low-temperature capacity retention was relatively higher, indicating that the two have a good synergistic effect, making the low-temperature performance of the battery better.

[0191] Comparing the data of Examples 1, 15 - 20, it can be seen that when adding electrolyte additives with a content of 0.1% - 5%, as the content of the electrolyte additive increases, the low-temperature DC resistance of the battery decreases and the low-temperature capacity retention rate increases. Among them, the improvement effect of the low-temperature performance of the battery in Example 1 with an electrolyte additive content of 3% is the most obvious. When the content of the electrolyte additive is higher than 5%, the low-temperature performance of the battery shows a certain degree of deterioration. Comparing the data of Examples 1, 23 - 28, it can be seen that when the content of the second solvent is below 10%, the more the content of the second solvent, the lower the low-temperature DC resistance of the battery and the greater the low-temperature capacity retention rate. When the content of the second solvent is greater than 10%, as the content of the second solvent increases, the low-temperature impedance of the battery increases, the low-temperature capacity decreases, and the low-temperature performance deteriorates.

[0192] The above is the exemplary embodiment of the present application. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present application, several improvements and refinements can still be made, and these improvements and refinements are also regarded as the protection scope of the present application.

Claims

1. A non-aqueous electrolyte, characterized in that, The non-aqueous electrolyte includes a first solvent, a second solvent, and an electrolyte additive, and the electrolyte additive includes Li 3+x PO 4-x N x , Li 3y La 2 / 3-y TiO3, Li 7-z La3Zr 2-z Ta z O 12 , Li 1+m Al m Ti 2-m (PO4)3, Li 1+n Al n Ge 2-n (PO4)3, where 0 < x ≤ 0.5, 0 < y ≤ 0.16, 0 < z ≤ 0.5, 0 < m ≤ 0.5, 0 < n ≤ 0.5, and the second solvent includes one or more of the compounds represented by formulas (I) to (IV): Wherein, R1 and R2 are each independently selected from any one of a halogen atom, a hydrogen atom, a C1-C3 hydrocarbon group, a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, and an alkylcarbonyl group, and at least one of R1 and R2 is a C1-C3 halogenated hydrocarbon group, a cyano group, a carboxyl group, an ester group, or an alkylcarbonyl group; R3 is selected from a single bond, a C1-C3 hydrocarbon group, or a C1-C3 halogenated hydrocarbon group; R4, R5, R6, R7, R8 and R 10 are each independently selected from any one of C1-C3 hydrocarbon groups, C1-C3 halogenated hydrocarbon groups, cyano groups, carboxyl groups, ester groups, and alkyl carbonyl groups, and at least one of R4 and R5 is a C1-C3 halogenated hydrocarbon group, cyano group, carboxyl group, ester group or alkyl carbonyl group, at least one of R6 and R7 is a C1-C3 halogenated hydrocarbon group, cyano group, carboxyl group, ester group or alkyl carbonyl group, and at least one of R8 and R 10 is a C1-C3 halogenated hydrocarbon group, cyano group, carboxyl group, ester group or alkyl carbonyl group; R9 is selected from a C1-C4 hydrocarbon group or a C1-C4 halogenated hydrocarbon group; The first solvent includes one or more of carbonate solvents, carboxylate solvents, and ether solvents other than the compounds represented by the formulas (I) to (IV).

2. The non-aqueous electrolyte according to claim 1, wherein The particle size D50 of the electrolyte additive is 10 nm - 300 nm.

3. The non-aqueous electrolyte according to claim 1 or 2, characterized in that, The mass percentage content of the electrolyte additive in the non-aqueous electrolyte is 0.1% - 10%.

4. The non-aqueous electrolyte according to any one of claims 1-3, characterized in that, The mass percentage content of the second solvent in the non-aqueous electrolyte is 2% - 60%.

5. The non-aqueous electrolyte according to any one of claims 1-4, characterized in that, The mass ratio of the first solvent to the second solvent is 0.16 - 45:

1.

6. The non-aqueous electrolyte according to any one of claims 1-5, characterized in that, The mass ratio of the second solvent to the electrolyte additive is 0.2 - 600:

1.

7. The non-aqueous electrolyte according to any one of claims 6, characterized in that, The mass ratio of the second solvent to the electrolyte additive is 0.4 - 40:

1.

8. The non-aqueous electrolyte according to any one of claims 1-7, characterized in that, The second solvent is selected from one or more of the compounds represented by the formulas (1) to (20):

9. The non-aqueous electrolyte according to any one of claims 1-8, characterized in that, The carbonate solvents include one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate; the carboxylate solvents include one or more of methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, and butyl butyrate; the ether solvents include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, 1,3-dioxolane, dimethoxymethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, polyethylene glycol dimethyl ether, isosorbide dimethyl ether, dipropylene glycol dimethyl ether, 1,1,2,2-tetrafluoroethyl ethyl ether, 1,1,2,3,3,3-pentafluoropropyl-2,2,2-trifluoroethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 2,2,3,3-tetrafluoropropyl dimethyl ether, 1,1,1,3,3,3-hexafluoroisopropyl methyl ether, and 2,2,2-trifluoroethyl ether.

10. The non-aqueous electrolyte according to any one of claims 1-9, characterized in that, The non-aqueous electrolyte further includes an electrolyte salt, and the electrolyte salt includes one or more of LiPF6, LiBF4, LiBOB, LiDFOB, LiDFOP, LiPO2F2, LiSbF6, LiAsF6, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, and LiN(SO2F)2.

11. The non-aqueous electrolyte according to any one of claims 1 to 10, characterized in that, The non-aqueous electrolyte further includes one or more of 1,3-propane sultone, 1,3-propene sultone, 1,4-butane sultone, vinylene carbonate, fluoroethylene carbonate, methylene methanedisulfonate, and ethylene sulfate.

12. A lithium-ion battery, characterized in that, The lithium-ion battery includes an electrolyte, and the electrolyte includes the non-aqueous electrolyte according to any one of claims 1-11.

13. An electrical device, characterized in that, The electrical device includes the lithium-ion battery according to claim 12.

Images