Electrolyte, secondary battery containing electrolyte and device

Abstract

The invention provides a high-entropy multi-diluent electrolyte which comprises a first diluent and a second diluent, the first diluent comprises a silane compound which does not dissolve lithium salt and a derivative of the silane compound, and the second diluent comprises at least one of halogenated ether, a derivative of halogenated ether, benzene and a derivative of benzene. The double diluents promote decomposition of lithium salt to form fluorine-containing SEI, so that formation of lithium dendrites is inhibited, and compared with a traditional low-concentration electrolyte and a single-diluent local high-concentration electrolyte, the high-entropy double-diluted local high-concentration electrolyte can prolong the cycle life of a lithium battery and improve the ionic conductivity of the electrolyte.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular, to an electrolyte, a secondary battery and a device containing the electrolyte. Background Art

[0002] Lithium batteries are widely used in smart phones, unmanned aerial vehicles and hybrid electric vehicles. However, with the advancement of technology, traditional lithium-ion batteries can no longer meet the demand. Metallic lithium has the advantages of low potential (-3.04V vs standard hydrogen electrode) and high specific capacity (3860mAh / g), and is a very excellent negative electrode material. However, the metal lithium negative electrode has the problem of lithium dendrites during the charging process. Lithium dendrites will cause two problems. First, after the lithium dendrites grow to a certain extent, they will break and become dead lithium, resulting in battery capacity decay; second, the lithium dendrites continue to grow and eventually pierce the diaphragm, resulting in a short circuit between the positive and negative electrodes and causing thermal runaway. Local high-concentration electrolyte can effectively delay the growth of lithium dendrites, but due to the introduction of inert components that do not complex with lithium ions, the overall conductivity of the solution decreases, the impedance of the liquid phase increases, and thus the power performance of the whole battery is reduced. Therefore, it is very important to develop a local high-concentration electrolyte system that can inhibit lithium dendrites, has high conductivity and high stability. Summary of the invention

[0003] In order to solve the above problems, the object of the present invention is to provide a high entropy multi-diluent electrolyte, which includes a first diluent and a second diluent, wherein the first diluent includes a silane compound and its derivatives that do not dissolve lithium salts, and the second diluent includes at least one of halogenated ethers and their derivatives, benzene and its derivatives. The double diluent promotes the decomposition of lithium salts to form a fluorine-containing SEI, thereby inhibiting the formation of lithium dendrites. Compared with traditional low-concentration electrolytes and local high-concentration electrolytes containing only a single diluent, high-entropy double-diluted local high-concentration electrolytes can extend the cycle life of lithium batteries and improve the ionic conductivity of the electrolyte.

[0004] In some embodiments of the present application, the first diluent includes a silane compound and a derivative thereof, and the silane compound and the derivative thereof include at least one of the compounds represented by Formula 1 to Formula 6,

[0005]

[0006] wherein R1 is selected from fluorinated C1-C6 alkyl, phenyl, C2-C6 alkenyl, R2, R3, and R4 are each independently selected from C1-C6 alkyl, C2-C6 alkenyl, and R5, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R15 , R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 , R 30 , R 31 , R 32 Each independently selected from C1-C6 alkyl;

[0007] In some embodiments of the present application, the first diluent includes at least one of (heptafluoropropyl)trimethylsilane, (trifluoromethyl)trimethylsilane, triethyl(trifluoromethyl)silane, (difluoromethyl)trimethylsilane, (chlorodifluoromethyl)trimethylsilane, trimethyl(pentafluoroethyl)silane, (pentafluoroethyl)trimethylsilane, trimethyl(tridecafluorohexyl)silane, trimethylphenylsilane, tetravinylsilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylpropoxysilane, isopropoxytrimethylsilane, tert-butoxytrimethylsilane, hexamethyldisiloxane, tetramethyldivinyldisiloxane, heptamethyldisilazane, N,N-dimethyltrimethylsilane and bis(dimethylamino)dimethylsilane.

[0008] In some embodiments of the present application, the halogenated ether and its derivatives include compounds shown in Formula 7,

[0009]

[0010] Among them, R 33 , R 34 , R 35 Each independently selected from H, CH3, C2H5, C3H7, F, CHF2, CHFCl, R 36 , R 37 Each independently selected from H, CF3, R 38 , R 39 Each is independently selected from H, F, CF3, C2HF4, C3HF6, C4HF8.

[0011] In some embodiments of the present application, the benzene and its derivatives include compounds shown in Formula 8,

[0012]

[0013] Among them, R 40Selected from F, CF3, CH3, R 41 , R 42 , R 43 , R 44 , R 45 Each is independently selected from H and F.

[0014] In some embodiments of the present application, the second diluent includes at least one of 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 1,1,2,2-tetrafluoroethyl ethyl ether, 1,1,1,3,3,3-hexafluoroisopropyl methyl ether, 2-chloro-1,1,2-trifluoroethyl methyl ester, trifluorotoluene, toluene, fluorobenzene, and 1,2-difluorobenzene.

[0015] In some embodiments of the present application, based on the total volume of the electrolyte, the content of the first diluent is 5 vol% to 90 vol%. In some embodiments of the present application, based on the total volume of the electrolyte, the content of the first diluent is 10 vol% to 90 vol%.

[0016] In some embodiments of the present application, based on the total volume of the electrolyte, the content of the second diluent is 5 vol% to 90 vol%. In some embodiments of the present application, based on the total volume of the electrolyte, the content of the second diluent is 10 vol% to 90 vol%.

[0017] Another object of the present invention is to provide a secondary battery, wherein the secondary battery comprises the electrolyte according to the present invention.

[0018] Another object of the present invention is to provide a device comprising the secondary battery according to the present invention.

[0019] Beneficial effects:

[0020] With the electrolyte of the present invention, the diluent is used to promote film formation and modulate the local solvation. By adding the first diluent and the second diluent to form a dual diluent system, and rationally controlling the content and ratio of the two, its "high entropy" solvation structure can effectively reduce the size of the solvation cluster, thereby improving the ionic conductivity of the electrolyte. Under high ionic conductivity conditions, lithium metal batteries show better cycle life and rate performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the above-mentioned purpose, features and advantages of the present invention easier to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein, so the present invention is not limited to the specific embodiments disclosed below.

[0022] Figure 1 The electrochemical performance of the half-cells prepared by the electrolytes of Example 1 and Comparative Example 1 is schematically shown; DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The relevant embodiments described herein are illustrative and used to provide a basic understanding of the present application. The embodiments of the present application should not be interpreted as limiting the present application. All other embodiments obtained by those skilled in the art based on the technical scheme provided by the present application and the embodiments given belong to the scope of protection of the present application.

[0024] Unless otherwise specified, the terms used in this application have the commonly known meanings generally understood by those skilled in the art. Unless otherwise specified, the numerical values ​​of the various parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the examples of this application).

[0025] A list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, the phrase "at least one of A or B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, the phrase "at least one of A, B, or C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single component or multiple components. Item B may contain a single component or multiple components. Item C may contain a single component or multiple components.

[0026] In this document, "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0027] The electrolyte of the present application includes a first diluent and a second diluent.

[0028] The first diluent includes silane compounds and derivatives thereof.

[0029] In some embodiments of the present application, the silane compound and its derivatives include at least one of the compounds shown in Formula 1 to Formula 6,

[0030]

[0031]

[0032] wherein R1 is selected from fluorinated C1-C6 alkyl, phenyl, C2-C6 alkenyl, R2, R3, and R4 are each independently selected from C1-C6 alkyl, C2-C6 alkenyl, and R5, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 , R 30 , R 31 , R 32 Each is independently selected from C1-C6 alkyl.

[0033] In some embodiments of the present application, the silane compound and its derivatives include at least one of the compounds shown in Formula 1 to Formula 6,

[0034]

[0035] wherein R1 is selected from fluorinated C1-C3 alkyl, phenyl, C2-C4 alkenyl, R2, R3, and R4 are each independently selected from C1-C3 alkyl, C2-C4 alkenyl, and R5, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 , R 30 , R 31 , R 32 Each is independently selected from C1-C3 alkyl.

[0036] In some embodiments of the present application, the silane compound and its derivatives include at least one of the compounds shown in Formula 1 to Formula 6,

[0037]

[0038]

[0039] wherein R1 is selected from fluoromethane, fluoroethane, and vinyl, R2, R3, and R4 are each independently selected from C1-C3 alkyl, and R5, R6, R7, R8, R9, and R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 , R 30 , R 31 , R 32 Each is independently selected from C1-C3 alkyl.

[0040] In some embodiments of the present application, the first diluent includes at least one of (heptafluoropropyl)trimethylsilane, (trifluoromethyl)trimethylsilane, triethyl(trifluoromethyl)silane, (difluoromethyl)trimethylsilane, (chlorodifluoromethyl)trimethylsilane, trimethyl(pentafluoroethyl)silane, (pentafluoroethyl)trimethylsilane, trimethyl(tridecafluorohexyl)silane, trimethylphenylsilane, tetravinylsilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylpropoxysilane, isopropoxytrimethylsilane, tert-butoxytrimethylsilane, hexamethyldisiloxane, tetramethyldivinyldisiloxane, heptamethyldisilazane, N,N-dimethyltrimethylsilane and bis(dimethylamino)dimethylsilane.

[0041] In some embodiments of the present application, the first diluent includes hexamethyldisiloxane, isopropoxytrimethylsilane, trimethylmethoxysilane, (heptafluoropropyl)trimethylsilane, and heptamethyldisilazane.

[0042] In some embodiments of the present application, the second diluent includes at least one of halogenated ethers and their derivatives, benzene and its derivatives.

[0043] In some embodiments of the present application, the halogenated ether and its derivatives include compounds shown in Formula 7,

[0044]

[0045] Among them, R 33 , R 34 , R 35 Each independently selected from H, CH3, C2H5, C3H7, F, CHF2, CHFCl, R 36 , R 37 Each independently selected from H, CF3, R 38 , R 39 Each is independently selected from H, F, CF3, C2HF4, C3HF6, C4HF8.

[0046] In some embodiments of the present application, the benzene and its derivatives include compounds shown in Formula 8,

[0047]

[0048] Among them, R 40 Selected from F, CF3, CH3, R 41 , R 42 , R 43 , R 44 , R 45 Each is independently selected from H and F.

[0049] In some embodiments of the present application, the second diluent includes at least one of fluoroether, fluorobenzene and toluene.

[0050] In some embodiments of the present application, the halogenated ether and its derivatives include at least one of 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 1,1,2,2-tetrafluoroethyl ethyl ether, 1,1,1,3,3,3-hexafluoroisopropyl methyl ether and 2-chloro-1,1,2-trifluoroethyl methyl ester.

[0051] In some embodiments of the present application, the benzene and its derivatives include at least one of trifluorotoluene, monofluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,2,3-trifluorobenzene, 1,3,5-trifluorobenzene, 1,2,3,4-tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene and toluene.

[0052] In some embodiments of the present application, the second diluent includes at least one of 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 1,1,2,2-tetrafluoroethyl ethyl ether, 1,1,1,3,3,3-hexafluoroisopropyl methyl ether, 2-chloro-1,1,2-trifluoroethyl methyl ester, trifluorotoluene, monofluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,2,3-trifluorobenzene, 1,3,5-trifluorobenzene, 1,2,3,4-tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene and toluene.

[0053] In some embodiments of the present application, the second diluent includes at least one of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, 1,1,2,2-tetrafluoroethyl ether, 1,2-difluorobenzene, and 1,3,5-trifluorobenzene.

[0054] The ionic conductivity of weakly solvated electrolytes can be improved by increasing molecular diversity to modulate solvation entropy and adjust solvation structure. Compared with low-entropy electrolytes with fewer components, multicomponent high-entropy electrolytes with smaller ion clusters have higher diffusivities, mitigate concentration gradients during high-rate cycling, and achieve denser and more uniform deposition morphology of lithium metal.

[0055] In the electrolyte, the total volume of the first diluent and / or the second diluent is too small to form a local high-concentration lithium ion solvation structure, and the degree of modification of the interface SEI is insufficient; too much total volume will affect the dissolution of lithium salts in the solvent, making it impossible to form a uniform and stable solution system. At the same time, too little of a certain type of diluent in the mixed solution will lead to insufficient "high entropy" properties of the solution, causing the battery performance to approach that of an electrolyte system using a single diluent, either low ion conductivity or poor cycle performance.

[0056] In some embodiments of the present application, based on the total volume of the electrolyte, the content of the first diluent is in the range of 5 vol% to 90 vol%. In some embodiments of the present application, based on the total volume of the electrolyte, the content of the first diluent is 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, 45 vol%, 50 vol%, 55 vol%, 60 vol%, 65 vol%, 70 vol%, 75 vol%, 80 vol%, 85 vol%, 90 vol%, or any range consisting of these values ​​or any range consisting of these values.

[0057] In some embodiments of the present application, based on the total volume of the electrolyte, the content of the first diluent is in the range of 10 vol% to 60 vol%. In some embodiments of the present application, based on the total volume of the electrolyte, the content of the first diluent is 20 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, 45 vol%, 50 vol%, 55 vol%, 60 vol%, 65 vol%, 70 vol%, 75 vol%, 80 vol%, 85 vol%, 90 vol%, or any range consisting of these values ​​or any range consisting of these values.

[0058] In some embodiments of the present application, based on the total volume of the electrolyte, the content of the second diluent is in the range of 5 vol% to 90 vol%. In some embodiments of the present application, based on the total volume of the electrolyte, the content of the second diluent is 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, 45 vol%, 50 vol%, 55 vol%, 60 vol%, 65 vol%, 70 vol%, 75 vol%, 80 vol%, 85 vol%, 90 vol%, or any range consisting of these values ​​or any range consisting of these values.

[0059] In some embodiments of the present application, based on the total volume of the electrolyte, the content of the second diluent is in the range of 10 vol% to 60 vol%. In some embodiments of the present application, based on the total volume of the electrolyte, the content of the second diluent is 20 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, 45 vol%, 50 vol%, 55 vol%, 60 vol%, 65 vol%, 70 vol%, 75 vol%, 80 vol%, 85 vol%, 90 vol%, or any range consisting of these values ​​or any range consisting of these values.

[0060] In some embodiments of the present application, based on the total volume of the electrolyte, the sum of the contents of the first diluent and the second diluent is in the range of 20 vol% to 90 vol%. In some embodiments of the present application, based on the total volume of the electrolyte, the sum of the contents of the first diluent and the second diluent is 20 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, 45 vol%, 50 vol%, 55 vol%, 60 vol%, 65 vol%, 70 vol%, 75 vol%, 80 vol%, 85 vol%, 90 vol%, or any range consisting of these values ​​or any range consisting of these values.

[0061] Furthermore, when the total content of the first diluent and the second diluent is less than 20% of the total volume of the electrolyte, the solid electrolyte interface on the electrode surface is mainly formed by the action of non-aqueous organic solvent molecules, and the solvent-derived SEI film does not provide high protection for the lithium metal negative electrode; when the total content of the first diluent and the second diluent is more than 20% of the total volume of the electrolyte, a large amount of lithium salt anions enter the first layer of lithium ion solvation sheath, promoting the decomposition of anions on the lithium metal surface, thereby forming a passivation layer interface rich in lithium fluoride; when the total content of the first diluent and the second diluent is too high, the diluent will affect the dissolution of the lithium salt in the solvent, making it impossible to form a uniform and stable solution system.

[0062] In some embodiments of the present application, the volume ratio of the first diluent to the second diluent is 90:10 to 10:90. In some embodiments of the present application, the volume ratio of the first diluent to the second diluent is 25:75 to 75:25.

[0063] Furthermore, when the volume ratio of the first diluent to the second diluent is outside the range of 90:10 to 10:90, it indicates that most of the volume of the diluent is provided by a single system, and the solvent clusters formed by lithium ions are relatively single and do not have high entropy properties; when the volume ratio of the first diluent to the second diluent is within the range of 90:10 to 10:90, the first and second diluents compete with each other to form multiple solvent clusters, which increases the high entropy characteristics of the electrolyte and is beneficial to improving the lithium ion conductivity; when the volume ratio of the first diluent to the second diluent is within the range of 25:75 to 75:25, the Stokes diameter of the lithium ion solvent cluster is the smallest, which is most beneficial to improving the diffusion coefficient of lithium ions, thereby maximizing the ionic conductivity.

[0064] In some embodiments of the present application, the electrolyte includes a non-aqueous organic solvent. The non-aqueous organic solvent used in the electrolyte of the present application may be any organic solvent known in the prior art that can be used as a solvent for the electrolyte.

[0065] In some embodiments of the present application, the non-aqueous organic solvent includes, but is not limited to, cyclic carbonates, chain carbonates, cyclic carboxylates, chain carboxylates, cyclic ethers, chain ethers, phosphorus-containing organic solvents, sulfur-containing organic solvents and aromatic fluorine-containing solvents.

[0066] In some embodiments of the present application, the non-aqueous organic solvent includes at least one of carbonate, ether, phosphate, nitrile, sulfone, amide and siloxane organic reagents.

[0067] The siloxane organic reagent as a non-aqueous organic solvent contains at least 2 oxygen atoms, on this basis it can dissolve lithium salts, while the number of oxygen atoms in the siloxane compounds and their derivatives as diluents is less than or equal to 1. Therefore, the number of oxygen atoms in the siloxane compounds can be used as a basis for distinguishing whether they are non-aqueous organic solvents or silane-based diluents.

[0068] In some embodiments of the present application, the non-aqueous organic solvent used in the electrolyte of the present application is diphenyl carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, methyl ethyl carbonate, methyl acetate, methyl propionate, ethyl acetate, ethyl propionate, propyl acetate, propyl propionate, ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, butylene carbonate, ethylene glycol dimethyl ether, tetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, dimethyl methylphosphonate, acetonitrile, cyclopentane sulfone, methyl ethyl sulfone, dimethylformamide, dimethylacetamide, dimethyldimethoxysilane, methyltriethoxysilane, tetraethyl orthosilicate, dimethyldiethoxysilane and methyltrimethoxysilane. At least one of silane.

[0069] In some embodiments of the present application, the solvent used in the electrolyte of the present application is ethyl methyl carbonate, ethylene glycol dimethyl ether and a combination thereof.

[0070] In some embodiments of the present application, based on the total volume of the electrolyte, the content of the non-aqueous organic solvent is 10vol% to 95vol%. In some embodiments of the present application, based on the total volume of the electrolyte, the content of the non-aqueous organic solvent is 10vol%, 15vol%, 20vol%, 25vol%, 30vol%, 35vol%, 40vol%, 45vol%, 50vol%, 55vol%, 60vol%, 65vol%, 70vol%, 75vol%, 80vol%, 85vol%, 90vol%, 95vol% or any range consisting of these values ​​or any range consisting of these values. When the content of the non-aqueous organic solvent is too high, the solvent will replace the anions and enter the lithium ion solvation structure, resulting in the inability to form enough anion and cation aggregates, thereby affecting the composition and structure of the formed solid electrolyte interface film; when the content of the non-aqueous organic solvent is too low, there is not enough solvent to dissolve the lithium salt, resulting in the electrolyte being unable to form a uniform and stable solvent system.

[0071] In some embodiments of the present application, the electrolyte includes a lithium salt, and the lithium salt used in the electrolyte of the present application includes at least one of an inorganic lithium salt and an organic lithium salt. In some embodiments of the present application, the lithium salt includes at least one of lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluorooxalate borate (LiDFOB), lithium bis(oxalate borate) (LiBOB), lithium tetrafluoroborate (LiBF4) and lithium trifluoromethanesulfonate (LiSO3CF3). Further preferably, the lithium salt is lithium hexafluorophosphate (LiPF6) or lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). In some embodiments of the present application, the molar concentration of the lithium salt in the electrolyte is 0.5mol / L to 2.5mol / L. In some embodiments of the present application, the concentration of the lithium salt in the electrolyte is 0.5mol / L, 0.8mol / L, 1.0mol / L, 1.3mol / L, 1.5mol / L, 1.8mol / L, 2.0mol / L, 2.3mol / L, 2.5mol / L or any range consisting of these values. When the concentration of the lithium salt is too high, the overall viscosity of the electrolyte increases, resulting in decreased conductivity and battery performance; when the salt concentration is too low, the electrolyte conductivity is too low, resulting in the battery cycle not being able to proceed normally.

[0072] In some embodiments of the present application, based on the total mass of the electrolyte, the content of the lithium salt is 5 wt % to 28 wt %.

[0073] In some embodiments of the present application, based on the total weight of the electrolyte, the mass ratio of the first diluent, the second diluent, the non-aqueous organic solvent, and the lithium salt is (5.8-73.6): (7.9-73.6): (7.5-86.3): (7-37.4). In some embodiments of the present application, based on the total weight of the electrolyte, the mass ratio of the first diluent, the second diluent, the non-aqueous organic solvent, and the lithium salt is (11.6-68.6): (15.8-68.6): (14.2-55): (7-37.4).

[0074] The diluent accounts for a larger proportion of the total volume of the electrolyte and is mainly used to regulate the local solvation structure around lithium ions in the electrolyte; the additive accounts for a smaller proportion of the total volume of the electrolyte and is mainly used for positive and negative electrode film formation.

[0075] In some embodiments of the present application, the electrolyte may further include an additive, the additive including at least one of a cyclic carbonate containing a carbon-carbon double bond, a silyl-containing phosphate, a silyl-containing borate, a nitrile compound, a propanesulfonic acid pyridinium salt, a fluorocarbon, and a sulfonate. In some embodiments of the present application, the additive includes at least one of vinylene carbonate (VC), vinyl ethylene carbonate (VEC), tris(trimethylsilane) phosphate (TMSP), tris(trimethylsilane) borate (TMSB), succinonitrile (SN), adiponitrile (ADN), glutaronitrile (GLN), hexane trinitrile (HTN), fluoroethylene carbonate (FEC), and 1,3-propane sultone (PS). In some embodiments of the present application, the additive includes at least one of tris(trimethylsilane) phosphate (TMSP), fluoroethylene carbonate (FEC), and 1,3-propane sultone (PS).

[0076] In some embodiments of the present application, based on the total mass of the electrolyte, the mass content of the additive is 0.05%-10%. In some embodiments, based on the total mass of the electrolyte, the mass content of the additive is 0.05%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 6%, 7%, 8%, 9%, 10% or any value therebetween. In some embodiments of the present application, based on the total mass of the electrolyte, the mass content of the additive is 0.1%-5%.

[0077] The secondary battery according to the present invention includes a lithium metal battery, a lithium ion battery, a sodium ion battery, a lithium metal polymer battery or a lithium ion polymer battery. In some embodiments of the present application, the secondary battery of the present application includes a positive electrode, a negative electrode, a separator and / or a solid electrolyte, and an electrolyte.

[0078] The secondary battery according to the present invention can be used in the device according to the present invention, including but not limited to, laptop computers, input computers, mobile computers, electronic book players, portable phones, portable fax machines, portable copiers, portable printers, head-mounted stereo headphones, video recorders, LCD televisions, portable cleaners, portable CD players, mini CDs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium ion capacitors, etc.

[0079] The electrolyte used in the secondary battery of the present application is any of the above-mentioned electrolytes of the present application. In addition, the electrolyte used in the secondary battery of the present application may also include other electrolytes within the scope not departing from the gist of the present application.

[0080] The materials, compositions and manufacturing methods of the negative electrode plates that can be used in the embodiments of the present application include any technology disclosed in the prior art. In some embodiments of the present application, the negative electrode plates involved in the present disclosure include a negative electrode current collector and a negative electrode material layer, the negative electrode material layer is arranged on the surface of the negative electrode current collector, and the negative electrode material layer includes a negative electrode active material. The specific types of negative electrode active materials are not subject to specific restrictions and can be selected according to needs. In some embodiments of the present application, the negative electrode active material includes at least one of silicon-based materials, carbon-based materials, tin-based materials, phosphorus-based materials, lithium metal or lithium alloys. The silicon-based material includes at least one of silicon, silicon alloys, silicon oxide compounds and silicon carbon compounds. The carbon-based material includes at least one of graphite, soft carbon, hard carbon, carbon nanotubes and graphene. The tin-based material includes at least one of tin, tin oxide and tin alloy. The phosphorus-based material includes phosphorus and / or phosphorus complexes.

[0081] In some embodiments of the present application, the negative electrode material layer further comprises a binder, and based on the total mass of the negative electrode material layer, the mass percentage of the binder is 0.3%-5%. The binder improves the bonding between the negative electrode active material particles and the bonding between the negative electrode active material and the current collector.

[0082] In some embodiments of the present application, non-limiting examples of the binder include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.

[0083] In some embodiments of the present application, the negative electrode material layer may further include a conductive agent, and the mass percentage of the conductive agent is 0.3%-3% based on the total mass of the negative electrode material layer. The conductive agent may include any conductive material as long as it does not cause chemical changes. Non-limiting examples of conductive materials include carbon-based materials (e.g., natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, etc.), metal-based materials (e.g., metal powder, metal fiber, etc., such as copper, nickel, aluminum, silver, etc.), conductive polymers (e.g., polyphenylene derivatives) and mixtures thereof.

[0084] In some embodiments of the present application, the negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof.

[0085] In some embodiments of the present application, the negative electrode plate is lithium metal or lithium alloy.

[0086] In some embodiments of the present application, the lithium alloy includes lithium and a metal / metalloid that can be alloyed with lithium. For example, the metal / metalloid that can be alloyed with lithium is Si, Sn, Al, Ge, Pb, Bi, Sb, Si-Y alloy (wherein Y is an alkali metal, an alkaline earth metal, an element of Group 13-16, a transition metal, a rare earth element, or a combination thereof, except Si), or Sn-Y alloy (wherein Y is an alkali metal, an alkaline earth metal, an element of Group 13-16, a transition metal, a rare earth element, or a combination thereof, except Sn). Y can be Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po or a combination thereof.

[0087] The materials, compositions and manufacturing methods of the positive electrode sheets that can be used in the embodiments of the present application include any technology disclosed in the prior art.

[0088] In some embodiments of the present application, the positive electrode plate includes a current collector and a positive electrode active material layer located on the current collector. In some embodiments of the present application, the positive electrode active material includes, but is not limited to: lithium cobalt oxide (LiCoO2), lithium nickel cobalt manganese (NCM) ternary material, lithium nickel cobalt aluminum (NCA) ternary material, lithium iron phosphate (LiFePO4), lithium iron manganese phosphate (LiMn x Fe 1- x PO4) or lithium manganate (LiMn2O4).

[0089] In some embodiments of the present application, the positive electrode active material is Li[Ni 1-x-y Co x M y ]O2(M=Mn, Al, etc., such as lithium nickel cobalt manganese oxide Li[Ni 1-x-y Co x Mn y ]O2, 1-xy ≥ 0.5, lithium nickel cobalt aluminum oxide Li[Ni 1-x-y Co x Al y ]O2, 1-xy≥0.5).

[0090] In some embodiments of the present application, the positive electrode active material layer also includes a binder and optionally includes a conductive material. The binder improves the bonding between the positive electrode active material particles and also improves the bonding between the positive electrode active material and the current collector. In some embodiments of the present application, the binder includes: polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene 1,1-difluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (ester) styrene-butadiene rubber, epoxy resin or nylon, etc.

[0091] In some embodiments of the present application, the conductive material includes, but is not limited to: carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof. In some embodiments of the present application, the carbon-based material is selected from natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, or any combination thereof. In some embodiments of the present application, the metal-based material is selected from metal powder, metal fiber, copper, nickel, aluminum, or silver. In some embodiments of the present application, the conductive polymer is a polyphenylene derivative.

[0092] The material and shape of the separator used in the embodiments of the present invention are not particularly limited, and can be any technology disclosed in the prior art. In some embodiments of the present application, the separator includes a polymer or inorganic substance formed of a material that is stable to the electrolyte of the present invention.

[0093] For example, the diaphragm may include a substrate layer and a surface treatment layer. The substrate layer is a nonwoven fabric, a film or a composite film having a porous structure, and the material of the substrate layer includes at least one of polyethylene, polypropylene and polyethylene terephthalate. Specifically, polypropylene porous film, polyethylene porous film, polypropylene nonwoven fabric, polyethylene nonwoven fabric or polypropylene-polyethylene-polypropylene porous composite film can be selected.

[0094] A surface treatment layer is disposed on at least one surface of the substrate layer. The surface treatment layer may be a polymer layer or an inorganic layer, or a layer formed by mixing a polymer and an inorganic layer.

[0095] The inorganic layer includes inorganic particles and a binder, wherein the inorganic particles include at least one of aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium sulfate. The binder includes at least one of polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyethylene alkoxy, polymethyl methacrylate, polytetrafluoroethylene and polyhexafluoropropylene.

[0096] The polymer layer includes a polymer, and the material of the polymer includes at least one of polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyethylene alkoxide, polyvinylidene fluoride, and poly(vinylidene fluoride-hexafluoropropylene).

[0097] In some embodiments of the present application, the separator is a polyethylene (PE) separator coated with ceramic layers on both sides, wherein the thickness of the PE layer is in the range of 5 to 20 μm, and the coating thickness of each ceramic layer is in the range of 0 to 5 μm.

[0098] The material and shape of the solid electrolyte used in the embodiments of the present invention are not particularly limited, and can be any technology disclosed in the prior art. In some embodiments of the present application, the solid electrolyte includes but is not limited to a polymer solid electrolyte and an inorganic solid electrolyte.

[0099] In some embodiments of the present disclosure, the secondary battery involved in the present disclosure may include an outer package, which may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package of the secondary battery may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), etc.

[0100] In some embodiments of the present application, the present application further provides a device including the above-mentioned secondary battery, the device including but not limited to electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, power storage systems, etc. In order to meet the requirements of the device for high power and high energy density of the secondary battery, a battery pack or a battery module can be used.

[0101] In some embodiments of the present application, the device may be a mobile phone, a tablet computer, a laptop computer, etc. The device is usually required to be light and thin, and a secondary battery may be used as a power source.

[0102] In the following examples and comparative examples, the reagents, materials and instruments used are all commercially available unless otherwise specified.

[0103] Electrochemical performance test

[0104] 1. Coulomb efficiency test: Li / Cu battery is used for testing. The batteries are assembled in the order of negative electrode shell, spring, gasket, lithium sheet, diaphragm, copper sheet and positive electrode shell. 30 to 60 microliters of electrolyte are added to each battery to wet the diaphragm, and the battery is packaged.

[0105] First, the battery was charged at 0.1 mA / cm2 in the 0-2 V voltage range. 2 The pre-charge and discharge were performed at a current density of 1 mA / cm 2 The current density was 1 mA / cm 2 Lithium stripping was performed at a current density of 100 Å until the voltage was higher than 1 V, and the coulombic efficiency was calculated under the reverse polarity condition.

[0106] First coulomb efficiency = first cycle charging capacity / first cycle discharging capacity (current density is 1mA / cm 2 )

[0107] The 50th cycle coulombic efficiency = the 50th cycle charge capacity / the 50th cycle discharge capacity (current density is 1mA / cm 2 )

[0108] When the battery coulombic efficiency falls below 80% for the first time and fails to return to above 80% in the subsequent five cycles, the battery is considered to have failed.

[0109] 2. Electrolyte ion conductivity test method

[0110] Prepare samples: Prepare the electrolyte sample to be tested and ensure that the sample has no impurities or solid particles.

[0111] Measurement operation: Insert the electrode of the commercial conductivity meter into the electrolyte to be tested, ensure that the electrode is in full contact with the liquid and avoid interference from bubbles. Wait for a while and record the value after stabilization.

[0112] Examples and Comparative Examples

[0113] Example 1

[0114] 187 mg of LiFSI was dissolved in 0.2 ml of ethylene glycol dimethyl ether, and then 0.4 ml of hexamethyldisiloxane (first diluent) and 0.4 ml of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (second diluent) were added for dilution, and the electrolyte was obtained after stirring.

[0115] Example 2

[0116] 187 mg of LiFSI was dissolved in 0.2 ml of ethylene glycol dimethyl ether, and then 0.4 ml of isopropoxytrimethylsilane (first diluent) and 0.4 ml of 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether (second diluent) were added for dilution, and the electrolyte was obtained after stirring.

[0117] Example 3

[0118] 187 mg of LiFSI was dissolved in 0.2 ml of ethylene glycol dimethyl ether, and then 0.2 ml of isopropoxytrimethylsilane (first diluent) and 0.6 ml of 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether (second diluent) were added for dilution, and the electrolyte was obtained after stirring.

[0119] Example 4

[0120] 187 mg of LiFSI was dissolved in 0.2 ml of ethylene glycol dimethyl ether, and then 0.6 ml of isopropoxytrimethylsilane (first diluent) and 0.2 ml of 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether (second diluent) were added for dilution, and the electrolyte was obtained after stirring.

[0121] Example 5

[0122] 187 mg of LiFSI was dissolved in 0.78 ml of methyl ethyl carbonate, and then 0.11 ml of trimethylmethoxysilane and 0.11 ml of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether were added for dilution, and the mixture was stirred to obtain an electrolyte solution.

[0123] Example 6

[0124] 187 mg of LiFSI was dissolved in 0.78 ml of methyl ethyl carbonate, and then 0.11 ml of trimethylmethoxysilane was added for dilution and 0.11 ml of 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether was added, and the mixture was stirred to obtain an electrolyte solution.

[0125] Example 7

[0126] 100 mg of LiFSI was dissolved in 0.1 ml of methyl ethyl carbonate, and then 0.45 ml of (heptafluoropropyl)trimethylsilane and 0.45 ml of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether were added for dilution, and the mixture was stirred to obtain an electrolyte solution.

[0127] Example 8

[0128] 374 mg of LiFSI was dissolved in 0.4 ml of methyl ethyl carbonate, and then 0.3 ml of heptamethyldisilazane and 0.3 ml of 1,1,2,2-tetrafluoroethyl ether were added for dilution, and the electrolyte was obtained after stirring.

[0129] Example 9

[0130] 187 mg of LiFSI was dissolved in 0.3 ml of ethylene glycol dimethyl ether, and then 0.32 ml of trimethylmethoxysilane and 0.32 ml of 1,2-difluorobenzene were added for dilution, and the mixture was stirred to obtain an electrolyte solution.

[0131] Example 10

[0132] 187 mg of LiFSI was dissolved in 0.3 ml of ethylene glycol dimethyl ether, and then 0.21 ml of trimethylmethoxysilane and 0.43 ml of 1,3,5-trifluorobenzene were added for dilution, and the electrolyte was obtained after stirring.

[0133] Comparative Example 1

[0134] 187 mg of LiFSI was dissolved in 1 ml of ethylene glycol dimethyl ether and stirred to obtain an electrolyte solution.

[0135] Comparative Example 2

[0136] 187 mg of LiFSI was dissolved in 0.2 ml of ethylene glycol dimethyl ether, and 0.8 ml of 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether (second diluent) was added for dilution, and the electrolyte was obtained after stirring.

[0137] Comparative Example 3

[0138] 187 mg of LiFSI was dissolved in 0.78 ml of methyl ethyl carbonate, and 0.22 ml of trimethylmethoxysilane (first diluent) was added for dilution, followed by stirring to obtain an electrolyte solution.

[0139] Comparative Example 4

[0140] 187 mg of LiFSI was dissolved in 0.3 ml of ethylene glycol dimethyl ether, and 0.64 ml of 1,3,5-trifluorobenzene was added for dilution, and the electrolyte was obtained after stirring.

[0141] Table 1

[0142]

[0143]

[0144] The Li / Cu batteries manufactured using the electrolytes obtained from Examples 1-10 and Comparative Examples 1-4 were subjected to coulombic efficiency tests and cycle stability tests. The test results are shown in Table 2.

[0145] Table 2

[0146]

[0147]

[0148] Comparative Example 1 is a traditional low-concentration electrolyte (1M LiFSI) without adding any diluent. From its results, it can be seen that the battery cycle performance is extremely poor. Comparative Examples 2, 3, and 4 are local high-concentration electrolytes with only a single diluent added. From the results of Comparative Examples 2 and 4, it can be seen that the battery cycle performance is better when only the second type of diluent is added, but the ionic conductivity of the electrolyte is very poor, because the second type of diluent basically does not complex with lithium ions, resulting in a decrease in the overall conductivity of the solution and an increase in the impedance of the liquid phase. From the results of Comparative Example 3, it can be seen that the cycle performance of only adding the first diluent is poor. Examples 1-10 are local high-concentration electrolyte systems with double dilution added. Compared with Comparative Examples 1-4, Examples 1-10 show stable lithium metal cycle coulomb efficiency and longer life, while the ionic conductivity is improved, which effectively improves the cycle life of lithium metal / lithium ion batteries.

[0149] Although some exemplary embodiments of the present application have been illustrated and described, the present application is not limited to the disclosed embodiments. On the contrary, those skilled in the art will recognize that some modifications and changes may be made to the described embodiments without departing from the spirit and scope of the present application as described in the appended claims, and these modifications and changes also fall within the scope of protection of the present invention.

Claims

1. An electrolyte, characterized in that: The electrolyte comprises a non-aqueous organic solvent, a lithium salt, a first diluent and a second diluent, wherein the first diluent comprises a silane compound and a derivative thereof, and the second diluent comprises at least one of a halogenated ether and a derivative thereof, and benzene and a derivative thereof.

2. The electrolyte according to claim 1, characterized in that The silane compound and its derivatives include at least one of the compounds represented by Formula 1 to Formula 6, wherein R1 is selected from fluorinated C1-C6 alkyl, phenyl, C2-C6 alkenyl, R2, R3, and R4 are each independently selected from C1-C6 alkyl, C2-C6 alkenyl, and R5, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 , R 29 , R 30 , R 31 , R 32 Each independently selected from C1-C6 alkyl; and / or The content of the first diluent is 5 vol % to 90 vol % based on the total volume of the electrolyte.

3. The electrolyte according to claim 2, characterized in that The first diluent comprises at least one of (heptafluoropropyl)trimethylsilane, (trifluoromethyl)trimethylsilane, triethyl(trifluoromethyl)silane, (difluoromethyl)trimethylsilane, (chlorodifluoromethyl)trimethylsilane, trimethyl(pentafluoroethyl)silane, (pentafluoroethyl)trimethylsilane, trimethyl(tridecafluorohexyl)silane, trimethylphenylsilane, tetravinylsilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylpropoxysilane, isopropoxytrimethylsilane, tert-butoxytrimethylsilane, hexamethyldisiloxane, tetramethyldivinyldisiloxane, heptamethyldisilazane, N,N-dimethyltrimethylsilane and bis(dimethylamino)dimethylsilane; and / or Based on the total volume of the electrolyte, the content of the first diluent is 10 vol % to 90 vol %.

4. The electrolyte according to claim 1, characterized in that The halogenated ether and its derivatives include compounds shown in Formula 7, Among them, R 33 , R 34 , R 35 Each independently selected from H, CH3, C2H5, C3H7, F, CHF2, CHFCl, R 36 , R 37 Each independently selected from H, CF3, R 38 , R 39 Each independently selected from H, F, CF3, C2HF4, C3HF6, C4HF8; and / or The benzene and its derivatives include compounds shown in Formula 8, Among them, R 40 Selected from F, CF3, CH3, R 41 , R 42 , R 43 , R 44 , R 45 Each independently selected from H, F; and / or The content of the second diluent is 5 vol % to 90 vol % based on the total volume of the electrolyte.

5. The electrolyte according to claim 4, characterized in that The halogenated ether and its derivatives include at least one of 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, 1,1,2,2-tetrafluoroethyl ethyl ether, 1,1,1,3,3,3-hexafluoroisopropyl methyl ether and 2-chloro-1,1,2-trifluoroethyl methyl ester; and / or The benzene and its derivatives include at least one of trifluorotoluene, monofluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,2,3-trifluorobenzene, 1,3,5-trifluorobenzene, 1,2,3,4-tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene and toluene; and / or The content of the second diluent is 10 vol % to 90 vol % based on the total volume of the electrolyte.

6. The electrolyte according to claim 1, characterized in that The volume ratio of the first diluent to the second diluent is 90:10 to 10:90; and / or The mass ratio of the first diluent, the second diluent, the non-aqueous organic solvent and the lithium salt is (5.8-73.6): (7.9-73.6): (7.5-86.3): (7-37.4).

7. The electrolyte according to claim 1, characterized in that The non-aqueous organic solvent comprises at least one of carbonate, ether, phosphate, nitrile, sulfone, amide and siloxane organic reagents; and / or The lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium tetrafluoroborate and lithium trifluoromethanesulfonate.

8. The electrolyte according to claim 7, characterized in that The non-aqueous organic solvent comprises at least one of diphenyl carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, methyl ethyl carbonate, methyl acetate, methyl propionate, ethyl acetate, ethyl propionate, propyl acetate, propyl propionate, ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, butylene carbonate, ethylene glycol dimethyl ether, tetrahydrofuran, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetradiethylene glycol dimethyl ether, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, dimethyl methylphosphonate, acetonitrile, cyclopentane, methyl ethyl sulfone, dimethylformamide, dimethylacetamide, dimethyldimethoxysilane, methyltriethoxysilane, tetraethyl orthosilicate, dimethyldiethoxysilane and methyltrimethoxysilane; and / or Based on the total volume of the electrolyte, the content of the non-aqueous organic solvent is 10 vol% to 95 vol%; and / or The molar concentration of the lithium salt in the electrolyte is 0.5 mol / L to 2.5 mol / L.

9. A secondary battery, characterized in that: The secondary battery includes the electrolytic solution according to any one of claims 1 to 8.

10. A device, characterized in that: The device comprises the secondary battery according to claim 8 or 9.

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