Nonaqueous electrolyte solution, secondary battery, and electric device

Abstract

The invention provides a non-aqueous electrolyte, a secondary battery and an electric device. The non-aqueous electrolyte comprises lithium salts and an acid capturing additive, the lithium salts comprise a first lithium salt and a second lithium salt, the first lithium salt comprises LiPF6, the second lithium salt comprises one or more of LiN (CmF2m + 1SO2) (CnF2n + 1SO2), LiBF4, lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, LiAsF6 and LiClO4, m and n are respectively and independently natural numbers, and m and n can be respectively and independently natural numbers within 9; the structural formula of the acid capturing additive comprises at least one nitrogen atom with lone pair electrons. The first lithium salt plays a role in inhibiting corrosion of the aluminum foil; the second lithium salt can effectively reduce the acidity of the electrolyte and improve the cycle and storage performance of the battery cell; and the acid capturing additive reduces the consumption of negative electrode active lithium and protects the SEI film, so that the non-aqueous electrolyte can improve the cycle performance of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a non-aqueous electrolyte, a secondary battery, and an electrical device. Background Technology

[0002] Since its mass production in the late 20th century, lithium-ion batteries have been widely used in consumer electronics due to their advantages such as high energy density, no memory effect, and long cycle life. In recent years, the global environmental situation has become increasingly severe, and the shortage of fossil fuels has become more and more serious. Therefore, with the continuous maturation of materials and processes, lithium-ion batteries, as a clean energy source, are gradually becoming an important power source for automobiles.

[0003] Given the future trend towards higher voltages in lithium batteries, the requirements for safety, energy density, and other indicators will gradually increase. However, LiPF6, a commonly used lithium salt in electrolytes, still has many drawbacks. In the presence of trace amounts of water, LiPF6 reacts with water to generate HF, damaging the positive and negative electrode interface and causing rapid capacity decay. Furthermore, its poor thermal stability and susceptibility to decomposition lead to a decrease in lithium salt content, accelerating electrolyte consumption. The poor chemical and thermal stability of LiPF6 limits its application in high-voltage lithium-ion batteries. Summary of the Invention

[0004] This application provides a non-aqueous electrolyte, a secondary battery, and an electrical device to solve the problem that LiPF6 easily produces acid, damaging the positive and negative electrode interface and deteriorating the cell life.

[0005] The first aspect of this application provides a non-aqueous electrolyte comprising a lithium salt and an acid-collecting additive, wherein the lithium salt comprises a first lithium salt and a second lithium salt, the first lithium salt comprising LiPF6, and the second lithium salt comprising LiN(C) m F 2m+1 SO2)(C n F 2n+ The additive may contain one or more of the following: SO2, LiBF4, lithium dioxalatoborate, lithium difluorooxalatoborate, LiAsF6, and LiClO4, wherein m and n are each independent natural numbers, and m and n may be independent natural numbers less than 9; the structural formula of the acid-trapping additive includes at least one nitrogen atom with a lone pair of electrons.

[0006] During the first charge, the first lithium salt partially decomposes to produce fluoride ions. These fluoride ions react with the aluminum foil to form an aluminum fluoride passivation layer, which inhibits corrosion of the aluminum foil. The second lithium salt exhibits excellent thermal stability and hydrolysis resistance. Using it to replace part of the first lithium salt can effectively reduce electrolyte acidity and improve the cell's cycle and storage performance. Furthermore, the lone pair electrons on the nitrogen atoms of the acid-scavenging additive introduced into the non-aqueous electrolyte make the nitrogen atoms electron-rich, readily reacting with the electron-deficient R... +(such as H in HF) + A reaction occurs, producing N. + -R, reduces R + The probability of the negative electrode being reduced is reduced, thus reducing the consumption of active lithium in the negative electrode and protecting the SEI film. That is, the acid-collecting additive can further remove acidic impurities in the electrolyte (such as HF generated by the reaction of LiPF6 with trace water), reduce the damage of acidic impurities to the positive and negative electrode interfaces, thereby improving the battery cycle performance and achieving a long cell life.

[0007] In any embodiment of the first aspect, the acid-scavenging additive includes any one or more of compound 1 of general formula (I), compound 2 of general formula (II), compound 3 of general formula (III), compound 4 of general formula (IV), and compound 5 of general formula (V).

[0008] In general formula (I), Y 1 Y 2 Each is independently a C, N element, and R. 11 R 12 R 13 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 14 OH, -R 15 NR 16 R 17 -R 18 -OR 19 Any one of them, R 14 R 15 R 18 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 16 R 17 R 19 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups, and is R 16 R 17 R 19 Any carbon atom in the C1-C6 alkyl group may optionally be replaced by a heteroatom, which may be a N atom, a S atom, or a P atom, and optionally R 16 and R 17 Connect them into a ring;

[0009] In general formula (II), W 1 For C, N, O or S, W 2 For C or N, W 1 and W 2At least one of them is N; R 21 R 22 R 23 R 24 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 25 OH, -R 26 NR 27 R 28 -R 29 -OR 30 Any one of them, R 25 R 26 R 29 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 27 R 28 R 30 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups;

[0010] In general formula (III), A 1 A 2 A 3 A 4 A 5 A 6 A 7 Each can be independently represented by C or N, with A as an option. 1 Let N be an integer, and A be an integer. 2 A 3 A 4 A 5 A 6 A 7 Each is independently C or N; R 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be a hydrogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, -OH, or -R. 38 NR 39 R 40 Any one of alkoxy groups, R 38 Selected from any one of C0-C6 alkylene and C2-C6 alkenyl groups, R 39 R 40 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups;

[0011] In general formula (IV), X 1 X 2 X 3 Each of them is independently C or N, and at least one of them must be N. a and b are each independently integers from 0 to 3, and each of them is R. 41 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 42 OH, -R 43 NR 44 R 45 -R 46 -OR 47 Any one of them, R 42 R 43 R 46 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 44 R 45 R 47 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups.

[0012] In the general formula (V), V 1 V 2 V 3 Each is independently C or N, and at least one must be N, d is an integer from 0 to 3, and each R 51 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 52 OH, -R 53 NR 54 R 55 -R 56 -OR 57 Any one of them, R 52 R 53 R 56 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 54 R 55 R 57 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups.

[0013] In any embodiment of the first aspect, in general formula (I), R 11 R 12 R 13Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 14 OH, -R 15 NR 16 R 17 -R 18 -OR 19 Any one of them, R 14 R 15 R 18 Each is independently selected from any one of the C0-C3 alkylene groups, R 16 R 17 R 19 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C3 alkyl groups, and C1-C3 haloalkyl groups, and is R 16 R 17 R 19 Any carbon atom in the C1-C6 alkyl group may be replaced by a heteroatom, wherein the heteroatom is a nitrogen atom and optionally R. 16 and R 17 They connect to form 5-membered or 6-membered alicyclic rings.

[0014] In any implementation of the first aspect, R 11 R 12 R 13 Each is independently selected from hydrogen atoms, halogen atoms, methyl, ethyl, n-propyl, isopropyl, allyl, propargyl, -OH, -CH3OH, -NH2, -CH2NH2, -N(CH3)2, O-CH3, Any one of them; optionally, R 11 R 12 R 13 Each is independently selected from hydrogen atom, F atom, methyl, ethyl, n-propyl, isopropyl, -CH3OH, -CH2NH2, -N(CH3)2, O-CH3, Any one of them.

[0015] In any embodiment of the first aspect, the compound having the structure shown in general formula (III) is selected from any one or more of the following compounds:

[0016] Compound 1-1; Compounds 1-2; Compounds 1-3; Compounds 1-4; Compounds 1-5; Compounds 1-6; Compounds 1-7; Compounds 1-8; Compounds 1-9; Compounds 1-10; Compounds 1-11; Compounds 1-12.

[0017] In any embodiment of the first aspect, in general formula (II), W 1 For N, W 2 It can be C or N.

[0018] In any implementation of the first aspect, R 21 R 22 R 23 R 24 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 25 OH, -R 26 NR 27 R 28 -R 29 -OR 30 Any one of them, R 25 R 26 R 29 Each is independently selected from any one of the C0-C4 alkylene groups, R 27 R 28 R 30 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C4 alkyl groups, and C1-C4 haloalkyl groups.

[0019] In any implementation of the first aspect, R 21 R 22 R 23 R 24 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, propyl, cyclopropyl, allyl, propyne, -OH, -CH3OH, -NH2, -NHCH3, -CH2NH2, -N(CH3)2, O-CH3.

[0020] In any implementation of the first aspect, R 21 R 22 R 23 R 24 Each is independently selected from any one of hydrogen atom, F atom, methyl, propyl, cyclopropyl, allyl, -CH3OH, -NH2, -NHCH3, -N(CH3)2.

[0021] In any embodiment of the first aspect, the compound having the structure shown in general formula (II) is selected from any one or more of the following compounds:

[0022] Compound 2-1; Compound 2-2; Compounds 2-3; Compounds 2-4

[0023] Compounds 2-5; Compounds 2-6; Compounds 2-7; Compounds 2-8; Compounds 2-9.

[0024] In any embodiment of the first aspect, in general formula (III), A 1 For N, A 2 A 3 A 4 A 5 A 6 A 7 Each can be either C or N independently.

[0025] In any implementation of the first aspect, R 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be a hydrogen atom, a C1-C4 alkyl group, a C2-C4 alkenyl group, a C2-C4 alkynyl group, -OH, or -R. 38 NR 39 R 40 Any one of alkoxy groups, R 38 Selected from any one of C0-C3 alkylene groups, R 39 R 40 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C3 alkyl groups, and C1-C3 haloalkyl groups.

[0026] In any implementation of the first aspect, R 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be any one of hydrogen atom, methyl, ethyl, allyl, propyne, -OH, -NH2, -CH2NH2, -N(CH3)2, and O-CH3.

[0027] In any implementation of the first aspect, R 31 R 32 R33 R 34 R 35 R 36 R 37 It can be any one of hydrogen atom, methyl, ethyl, or O-CH3.

[0028] In any embodiment of the first aspect, the compound having the structure shown in general formula (III) is selected from any one or more of the following compounds:

[0029] Compound 3-1; Compound 3-2; Compound 3-3; Compounds 3-4; Compounds 3-5; Compounds 3-6; Compounds 3-7; Compounds 3-8; Compounds 3-9;

[0030] Compounds 3-10.

[0031] In any embodiment of the first aspect, in general formula (IV), X 1 Let N, X 2 X 3 Each can be either C or N independently.

[0032] In any implementation of the first aspect, a and b are each independently 0, 1, or 2.

[0033] In any implementation of the first aspect, each R 41 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 42 OH, -R 43 NR 44 R 45 -R 46 -OR 47 Any one of them, R 42 R 43 R 46 Each is independently selected from any one of the C0-C3 alkylene groups, R 44 R 45 R 47 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C4 alkyl groups, and C1-C4 haloalkyl groups.

[0034] In any implementation of the first aspect, each R 41Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, hydroxyl, -NH2, -N(CH3)2.

[0035] In any embodiment of the first aspect, the compound having the structure shown in general formula (IV) is selected from any one or more of the following compounds:

[0036] Compound 4-1; Compound 4-2; Compound 4-3; Compound 4-4; Compounds 4-5; Compounds 4-6.

[0037] In any implementation of the first aspect, in general formula (V), d is 0 or 1.

[0038] In any implementation of the first aspect, each R 51 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 52 OH, -R 53 NR 54 R 55 -R 56 -OR 57 Any one of them, R 52 R 53 R 56 Each is independently selected from any one of the C0-C3 alkylene groups, R 54 R 55 R 57 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C4 alkyl groups, and C1-C4 haloalkyl groups.

[0039] In any implementation of the first aspect, each R 51 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, n-propyl, isopropyl, hydroxyl, -NH2, -N(CH3)2.

[0040] In any implementation of the first aspect, each R 51 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, n-propyl, and isopropyl.

[0041] In any embodiment of the first aspect, the compound having the structure shown in general formula (V) is selected from any one or more of the following compounds:

[0042] Compound 5-1; Compound 5-2; Compound 5-3; Compounds 5-4; Compound 5-5; Compounds 5-6; Compounds 5-7; Compounds 5-8.

[0043] In any embodiment of the first aspect, the mass percentage of the acid-collecting additive in the non-aqueous electrolyte is W3, wherein 0.01% ≤ W3 ≤ 20%; optionally 0.05% ≤ W3 ≤ 10%, and more preferably 0.5% ≤ W3 ≤ 5%.

[0044] In any embodiment of the first aspect, the second lithium salt includes any one or more of Li(FSO2)2N, Li(CF3SO2)(FSO2)N, Li(CF3SO2)2N, Li(C2F5SO2)2N, and Li(CF3SO2)(C2F5SO2)N.

[0045] In any embodiment of the first aspect, the concentration range C1 of the first lithium salt in the non-aqueous electrolyte satisfies 0.1 mol / L ≤ C1 ≤ 1.5 mol / L; optionally, it satisfies 0.2 mol / L ≤ C1 ≤ 1.2 mol / L.

[0046] In any embodiment of the first aspect, the concentration range C2 of the second lithium salt in the non-aqueous electrolyte satisfies 0.1 mol / L ≤ C2 ≤ 1.5 mol / L, and more preferably 0.2 mol / L ≤ C2 ≤ 1 mol / L.

[0047] In any embodiment of the first aspect, the concentration of lithium salt in the non-aqueous electrolyte ranges from 0.5 mol / L to 2.5 mol / L, and is optionally from 0.8 mol / L to 2 mol / L; optionally, the molar ratio of the first lithium salt to the second lithium salt is 5:1 to 1:6; further optionally, the molar ratio of the first lithium salt to the second lithium salt is 3.5:1 to 1:5.

[0048] The second aspect of this application provides a secondary battery, including a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte is a non-aqueous electrolyte provided in any embodiment of the first aspect described above.

[0049] In any embodiment of the second aspect, the negative electrode sheet includes a negative electrode active material, which satisfies one or two of the following conditions:

[0050] 1) The BET specific surface area of ​​the negative electrode active material is 0.5 m². 2 / g-2.0m 2 / g, optional 0.8m 2 / g-1.5m2 / g;

[0051] 2) The volume average particle size Dv50 of the negative electrode active material is controlled within 3μm≤Dv50≤50μm, optionally 5μm≤Dv50≤30μm, and further optionally 12μm≤Dv50≤25μm.

[0052] In any embodiment of the second aspect, the negative electrode sheet includes a negative current collector and a negative active material coating disposed on one or both sides of the negative current collector, wherein the porosity of the negative active material coating is 30% to 45%, optionally 37% to 42%.

[0053] A third aspect of this application provides an electrical device including a secondary battery, which includes the secondary battery provided in any embodiment of the second aspect. Attached Figure Description

[0055] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0056] Figure 1 This is a schematic diagram of a secondary battery according to one embodiment of this application.

[0057] Figure 2 yes Figure 1 An exploded view of a secondary battery according to one embodiment of this application is shown.

[0058] Figure 3 This is a schematic diagram of a battery module according to one embodiment of this application.

[0059] Figure 4 This is a schematic diagram of a battery pack according to one embodiment of this application.

[0060] Figure 5 yes Figure 4 An exploded view of a battery pack according to one embodiment of this application is shown.

[0061] Figure 6 This is a schematic diagram of an electrical device that uses a secondary battery as a power source according to one embodiment of this application.

[0062] The accompanying drawings are not drawn to scale.

[0063] Explanation of reference numerals in the attached figures:

[0064] 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Secondary battery cell; 51 Housing; 52 Electrode assembly; 53 Top cover assembly. Detailed Implementation

[0065] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0066] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the non-aqueous electrolyte, secondary battery, and electrical device of this application. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0067] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0068] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0069] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0070] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0071] Unless otherwise specified, the terms "comprising" and "including" as used in this application are open-ended. For example, "comprising" and "including" may mean that other components not listed may also be included or contained.

[0072] Unless otherwise specified, the term "or" is inclusive in this application. For example, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0073] As described in the background section, LiPF6 reacts with water in the presence of trace amounts of water to generate HF, which damages the positive and negative electrode interface and causes rapid capacity decay of the battery. Furthermore, LiPF6 has poor thermal stability and is easily decomposed, leading to a decrease in lithium salt content and accelerating electrolyte consumption. Therefore, the poor chemical and thermal stability of LiPF6 makes the positive and negative electrode interface easily damaged, thus degrading the cell lifespan. To address this problem, this application provides a non-aqueous electrolyte, a secondary battery, and an electrical device.

[0074] [Non-aqueous electrolyte]

[0075] The first embodiment of this application provides a non-aqueous electrolyte, comprising a lithium salt and an acid-collecting additive. The lithium salt includes a first lithium salt and a second lithium salt. The first lithium salt includes LiPF6, and the second lithium salt includes LiN(C) m F 2m+1 SO2)(C n F 2n+1 The additive comprises one or more of SO2, LiBF4, lithium dioxalatoborate (LiBOB), lithium difluorooxalatoborate (LiDFOB), LiAsF6, and LiClO4, wherein m and n are each an independent natural number, and m and n may be each an independent natural number less than 9; the structural formula of the acid-trapping additive includes at least one nitrogen atom with a lone pair of electrons.

[0076] During the first charge, the first lithium salt partially decomposes to produce fluoride ions. These fluoride ions react with the aluminum foil to form an aluminum fluoride passivation layer, which inhibits corrosion of the aluminum foil. The second lithium salt exhibits excellent thermal stability and hydrolysis resistance. Using it to replace part of the first lithium salt can effectively reduce electrolyte acidity and improve the cell's cycle and storage performance. Furthermore, the lone pair electrons on the nitrogen atoms of the acid-scavenging additive introduced into the non-aqueous electrolyte make the nitrogen atoms electron-rich, readily reacting with the electron-deficient R... + (such as H in HF) + A reaction occurs, producing N. + -R, reduces R + The probability of the negative electrode being reduced is reduced, thus reducing the consumption of active lithium in the negative electrode and protecting the SEI film. That is, the acid-collecting additive can further remove acidic impurities in the electrolyte (such as HF generated by the reaction of LiPF6 with trace water), reduce the damage of acidic impurities to the positive and negative electrode interfaces, thereby improving the battery cycle performance and achieving a long cell life.

[0077] In some embodiments, the aforementioned acid-scavenging additive includes any one or more of compound 1 represented by general formula (I), compound 2 represented by general formula (II), compound 3 represented by general formula (III), compound 4 represented by general formula (IV), and compound 5 represented by general formula (V).

[0078] In general formula (I), Y1 and Y2 are independently C and N elements, respectively, and R 11 R 12 R 13 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 14 OH, -R 15 NR 16 R 17 -R 18 -OR 19 Any one of them, R 14 R 15 R 18 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 16 R 17 R 19 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups, and is R 16 R 17 R 19 Any carbon atom in the C1-C6 alkyl group may optionally be replaced by a heteroatom, which may be a N atom, a S atom, or a P atom, and optionally R 16 and R17 Connect them into a ring;

[0079] In general formula (II), W 1 For C, N, O or S, W 2 For C or N, W 1 and W 2 At least one of them is N; R 21 R 22 R 23 R 24 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 25 OH, -R 26 NR 27 R 28 -R 29 -OR 30 Any one of them, R 25 R 26 R 29 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 27 R 28 R 30 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups;

[0080] In general formula (III), A 1 A 2 A 3 A 4 A 5 A 6 A 7 Each can be independently represented by C or N, with A as an option. 1 Let N be an integer, and A be an integer. 2 A 3 A 4 A 5 A 6 A 7 Each is independently C or N; R 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be a hydrogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, -OH, or -R. 38 NR 39 R 40Any one of alkoxy groups, R 38 Selected from any one of C0-C6 alkylene and C2-C6 alkenyl groups, R 39 R 40 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups;

[0081] In general formula (IV), X 1 X 2 X 3 Each of them is independently C or N, and at least one of them must be N. a and b are each independently integers from 0 to 3, and each of them is R. 41 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 42 OH, -R 43 NR 44 R 45 -R 46 -OR 47 Any one of them, R 42 R 43 R 46 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 44 R 45 R 47 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups.

[0082] In the general formula (V), V 1 V 2 V 3 Each is independently C or N, and at least one must be N, d is an integer from 0 to 3, and each R 51 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 52 OH, -R 53 NR 54 R 55 -R 56 -OR 57 Any one of them, R 52 R 53 R 56 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 54 R 55R 57 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups.

[0083] In some implementations, in general formula (I), R 11 R 12 R 13 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 14 OH, -R 15 NR 16 R 17 -R 18 -OR 19 Any one of them, R 14 R 15 R 18 Each is independently selected from any one of the C0-C3 alkylene groups, R 16 R 17 R 19 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C3 alkyl groups, and C1-C3 haloalkyl groups, and is used as said R. 16 R 17 R 19 Any carbon atom in the C1-C6 alkyl group may optionally be replaced by a heteroatom, said heteroatom being a nitrogen atom, and said R may optionally be... 16 and R 17 They connect to form 5-membered or 6-membered alicyclic rings.

[0084] In some implementations, R can optionally 11 R 12 R 13 Each is independently selected from hydrogen atoms, halogen atoms, methyl, ethyl, n-propyl, isopropyl, allyl, propargyl, -OH, -CH3OH, -NH2, -CH2NH2, -N(CH3)2, O-CH3, Any one of them; optionally, R 11 R 12 R 13 Each is independently selected from hydrogen atom, F atom, methyl, ethyl, n-propyl, isopropyl, -CH3OH, -CH2NH2, -N(CH3)2, O-CH3, Any one of them.

[0085] In some embodiments, optionally, the compound having the structure shown in general formula (III) is selected from any one or more of the following compounds: Compound 1-1; Compounds 1-2; Compounds 1-3; Compounds 1-4; Compounds 1-5; Compounds 1-6; Compounds 1-7; Compounds 1-8; Compounds 1-9; Compounds 1-10; Compounds 1-11; Compounds 1-12.

[0086] In some implementations, in general formula (II), W 1 For N, W 2 For C or N. When W 1 W 2 When all elements are N, it is possible to interact with R. + The more nitrogen atoms involved in the reaction, the more readily the R atoms in the electrolyte will be consumed. + This improves battery initial efficiency and battery cycle performance.

[0087] In some implementations, R can optionally 21 R 22 R 23 R 24 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 25 OH, -R 26 NR 27 R 28 -R 29 -OR 30 Any one of them, R 25 R 26 R 29 Each is independently selected from any one of the C0-C4 alkylene groups, R 27 R 28 R 30 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C4 alkyl groups, and C1-C4 haloalkyl groups.

[0088] In some implementations, R may optionally be used. 21 R 22 R 23 R 24 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, propyl, cyclopropyl, allyl, propyne, -OH, -CH3OH, -NH2, -NHCH3, -CH2NH2, -N(CH3)2, O-CH3.

[0089] In some implementations, R may optionally be used. 21 R 22 R 23 R 24 Each is independently selected from any one of hydrogen atom, F atom, methyl, propyl, cyclopropyl, allyl, -CH3OH, -NH2, -NHCH3, -N(CH3)2.

[0090] In some embodiments, optionally, the compound having the structure shown in general formula (II) is selected from any one or more of the following compounds: Compound 2-1; Compound 2-2; Compounds 2-3; Compounds 2-4 Compounds 2-5; Compounds 2-6; Compounds 2-7; Compounds 2-8; Compounds 2-9.

[0091] In some implementations, in general formula (III), A 1 For N, A 2 A 3 A 4 A 5 A 6 A 7 Each can be either C or N independently. When A 2 A 3 A 4 A 5 A 6 A 7 The more N elements there are, the more likely it is to interact with R. + The more nitrogen atoms involved in the reaction, the more easily the R atoms in the electrolyte are consumed. + The more prominent the effect, the better the battery's initial efficiency and battery cycle performance.

[0092] In some implementations, R may optionally be used. 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be a hydrogen atom, a C1-C4 alkyl group, a C2-C4 alkenyl group, a C2-C4 alkynyl group, -OH, or -R. 38 NR 39 R 40 Any one of alkoxy groups, R 38 Selected from any one of C0-C3 alkylene groups, R 39 R40 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C3 alkyl groups, and C1-C3 haloalkyl groups.

[0093] In some implementations, R may optionally be used. 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be any one of hydrogen atom, methyl, ethyl, allyl, propyne, -OH, -NH2, -CH2NH2, -N(CH3)2, and O-CH3.

[0094] In some implementations, R may optionally be used. 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be any one of hydrogen atom, methyl, ethyl, or O-CH3.

[0095] In some embodiments, optionally, the compound having the structure shown in general formula (III) is selected from any one or more of the following compounds: Compound 3-1; Compound 3-2; Compound 3-3; Compounds 3-4; Compounds 3-5; Compounds 3-6; Compounds 3-7; Compounds 3-8; Compounds 3-9; Compounds 3-10.

[0096] In some implementations, in formula (IV), X 1 Let N, X 2 X 3 Each can be either C or N independently. X 1 X 2 X 3 The more N elements there are, the more likely it is to interact with R. + The more nitrogen atoms involved in the reaction, the more easily the R atoms in the electrolyte are consumed. + The more obvious the effect of improving battery initial efficiency and battery cycle performance, the better.

[0097] In some implementations, a and b may optionally be 0, 1, or 2 independently.

[0098] In some implementations, optionally, each R 41 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 42 OH, -R 43 NR 44 R 45 -R 46 -OR 47 Any one of them, R 42 R 43 R 46 Each is independently selected from any one of the C0-C3 alkylene groups, R 44 R 45 R 47 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C4 alkyl groups, and C1-C4 haloalkyl groups.

[0099] In some implementations, optionally, each R 41 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, hydroxyl, -NH2, -N(CH3)2.

[0100] In some embodiments, optionally, the compound having the structure shown in general formula (IV) is selected from any one or more of the following compounds: Compound 4-1; Compound 4-2; Compound 4-3; Compound 4-4; Compounds 4-5; Compounds 4-6.

[0101] In some implementations, d in general formula (V) is 0 or 1.

[0102] In some implementations, optionally, each R 51 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 52 OH, -R 53 NR 54 R 55 -R 56 -OR 57 Any one of them, R 52 R 53 R 56 Each is independently selected from any one of the C0-C3 alkylene groups, R 54 R 55 R 57Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C4 alkyl groups, and C1-C4 haloalkyl groups.

[0103] In some implementations, optionally, each R 51 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, n-propyl, isopropyl, hydroxyl, -NH2, -N(CH3)2.

[0104] In some implementations, optionally, each R 51 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, n-propyl, and isopropyl.

[0105] In some embodiments, optionally, the compound having the structure shown in general formula (V) is selected from any one or more of the following compounds: Compound 5-1; Compound 5-2; Compound 5-3; Compounds 5-4; Compound 5-5; Compounds 5-6; Compounds 5-7; Compounds 5-8.

[0106] In some embodiments, the mass percentage of the acid-collecting additive in the non-aqueous electrolyte is W3, wherein 0.01% ≤ W3 ≤ 20%; optionally, 0.05% ≤ W3 ≤ 10%, and more preferably, 0.5% ≤ W3 ≤ 5%. Experiments show that with the above-mentioned mass percentage of the electrolyte additive, the electrolyte additive can not only fully consume R in the electrolyte, but also... + And it will not be excessive, thus more stably improving the battery's first efficiency and battery cycle performance.

[0107] In some embodiments, the second lithium salt includes any one or more of Li(FSO2)2N, Li(CF3SO2)(FSO2)N, Li(CF3SO2)2N, Li(C2F5SO2)2N, and Li(CF3SO2)(C2F5SO2)N. The above-mentioned fluorosulfonylimide lithium salts exhibit better thermal stability and hydrolysis resistance, thus allowing for better control of electrolyte acidity.

[0108] In some embodiments, the concentration range C1 of the first lithium salt in the non-aqueous electrolyte satisfies 0.1 mol / L ≤ C1 ≤ 1.5 mol / L; optionally, it is 0.2 mol / L ≤ C1 ≤ 1.2 mol / L. This can not only fully achieve the effect of lithium ion transport, but also reduce the amount added compared to conventional electrolytes, thereby effectively controlling the problem of instability at the positive and negative interfaces caused by the generation of HF by the first lithium salt.

[0109] In some embodiments, optionally, the concentration range C2 of the second lithium salt in the non-aqueous electrolyte satisfies 0.1 mol / L ≤ C2 ≤ 1.5 mol / L, and more optionally, 0.2 mol / L ≤ C2 ≤ 1 mol / L. Sufficient second lithium salt content effectively controls the problems of increased side reactions, increased gas production, and deteriorated high-temperature cycling and storage performance of lithium-ion batteries under high temperature or full charge conditions. However, lithium fluorosulfonylimide oxidizes during high-voltage charging. The anions of the oxidation products react with the aluminum foil, producing byproducts that dissolve in the electrolyte, thus corroding the aluminum foil and deteriorating the electrolyte performance. Therefore, further controlling the upper limit of the second lithium salt content avoids the problem of excessively high second lithium salt content accelerating the corrosion of the positive electrode current collector aluminum foil, leading to a significant increase in battery polarization.

[0110] In some embodiments, the concentration of lithium salt in the non-aqueous electrolyte ranges from 0.5 mol / L to 2.5 mol / L, and optionally from 0.8 mol / L to 2 mol / L; optionally, the molar ratio of the first lithium salt to the second lithium salt is 5:1 to 1:6; further optionally, the molar ratio of the first lithium salt to the second lithium salt is 3.5:1 to 1:5. The combination of the first and second lithium salts in the above ratio not only gives the electrolyte high conductivity, which is beneficial for lithium ion migration, but also further improves the thermal stability of the electrolyte, thus enhancing the safety performance of the secondary battery.

[0111] In some embodiments, the non-aqueous electrolyte further includes an organic solvent. The type of organic solvent is not particularly limited and can be selected according to actual needs. Specifically, the organic solvent may also include one or more of other types of chain carbonates, cyclic carbonates, and carboxylic acid esters. The types of chain carbonates, cyclic carbonates, and carboxylic acid esters are not specifically limited and can be selected according to actual needs. Preferably, the organic solvent may also include one or more of diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, ethylene carbonate, propylene carbonate, butenyl carbonate, γ-butyrolactone, methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, methyl propionate, and tetrahydrofuran.

[0112] In some embodiments, the electrolyte may optionally include other additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives capable of improving certain battery performance, such as additives improving battery overcharge performance, additives improving battery high-temperature or low-temperature performance, etc. In some embodiments, the additives are selected from at least one of the following: cyclic carbonate compounds containing unsaturated bonds, halogen-substituted cyclic carbonate compounds, sulfate compounds, sulfite compounds, sulfonyl lactone compounds, disulfonic acid compounds, nitrile compounds, aromatic compounds, isocyanate compounds, phosphonitrile compounds, cyclic anhydride compounds, phosphite compounds, phosphate compounds, borate ester compounds, and carboxylic acid ester compounds.

[0113] [Rechargeable Battery]

[0114] Secondary batteries, also known as rechargeable batteries or storage batteries, are batteries that can be recharged after being discharged to activate the active materials and continue to be used.

[0115] Typically, a secondary battery consists of a positive electrode, a negative electrode, a separator, and an electrolyte. During charging and discharging, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing active ions to pass through. The electrolyte, also positioned between the positive and negative electrodes, mainly serves to conduct active ions.

[0116] The second embodiment of this application provides a secondary battery, including a positive electrode, a negative electrode, and an electrolyte, wherein the electrolyte is any one of the non-aqueous electrolytes provided in the first embodiment above.

[0117] This application utilizes a first lithium salt and a second lithium salt in the electrolyte to achieve efficient lithium-ion transport. Furthermore, by leveraging the excellent thermal stability and hydrolysis resistance of the second lithium salt, the acidity of the electrolyte is effectively reduced, improving the cycle and storage performance of the battery cell. Simultaneously, by utilizing acid-scavenging additives in the electrolyte to react with acidic impurities generated in the electrolyte, the damage of acidic impurities to the positive and negative electrode interfaces is reduced, further enhancing the initial efficiency and cycle performance of the battery cell.

[0118] [Negative electrode plate]

[0119] The negative electrode sheet includes a negative current collector and a negative active material coating disposed on at least one surface of the negative current collector, wherein the negative active material coating includes a negative active material.

[0120] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0121] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0122] In some embodiments, the negative electrode active material may be a negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0123] In some embodiments, the negative electrode active material satisfies one or two of the following conditions: 1) the BET specific surface area of ​​the negative electrode active material is 0.5 m². 2 / g-2.0m 2 / g, optional 0.8m 2 / g-1.5m 2 / g; 2) The volume average particle size Dv50 of the negative electrode active material is controlled within 3μm≤Dv50≤50μm, optionally 5μm≤Dv50≤30μm, and further optionally 12μm≤Dv50≤25μm.

[0124] By controlling the BET specific surface area of ​​the negative electrode active material within the above-mentioned range, the negative electrode active material has sufficient lithium acceptance capacity during charging, avoiding lithium deposition on the negative electrode surface and thus improving battery stability. At the same time, it also avoids excessive contact area between the negative electrode active material and the electrolyte, which would lead to significant side reactions and generate more gas, making the negative electrode loose and porous, thereby effectively maintaining the long cycle life of the battery.

[0125] The test method for the BET specific surface area of ​​the above-mentioned negative electrode active material can refer to the standard GB / T19587-2004 "Determination of specific surface area of ​​solid materials by gas adsorption BET method".

[0126] By controlling the Dv50 of the negative electrode active material within the above range, the coating surface formed during the coating preparation of the electrode sheet is more uniform. Moreover, it effectively controls the repeated damage to the SEI caused by the violent side reaction between the negative electrode active material and the electrolyte due to excessively small particle size, as well as the increase in lithium consumption, thereby improving the stability of the initial battery capacity and cycle life.

[0127] In this application, the volume average particle size Dv50 of the negative electrode active material has a well-known meaning in the art, that is, the particle size corresponding to the cumulative particle size distribution percentage reaching 50% on the particle volume distribution curve. It can be determined using instruments and methods known in the art, such as using a laser particle size analyzer (e.g., Master Size 3000) according to GB / T19077-2016 Particle Size Distribution Laser Diffraction Method.

[0128] When it is necessary to determine the BET specific surface area and volume average particle size Dv50 of the negative electrode active material on the negative electrode sheet, the film layer of the negative electrode sheet is scraped off from the current collector, dissolved in a solvent, filtered, dried and collected, and then tested using the above method.

[0129] In some embodiments, the porosity of the negative electrode active material coating is 30% to 45%, optionally 37% to 42%.

[0130] When the porosity of the negative electrode active material coating is within the above range, the pores between the particles inside the electrode are sufficient, the particle structure is not easily damaged by compression, the electrolyte is more easily wetted, polarization is controlled, and the stability of the long-term cycle performance of the battery cell is improved; moreover, it effectively controls the excessive rebound of the electrode due to the excessive porosity of the negative electrode active material coating and the reduction of actual compaction of the electrode in actual use, thereby giving the battery cell a higher energy density.

[0131] The porosity of the negative electrode active material coating on the negative electrode sheet was tested using an AccuPycⅡ1340 true density meter according to the instrument's instruction manual. The porosity of the negative electrode active material coating on the electrode sheet can be controlled by adjusting the particle size of the negative electrode active material and the pressure during the cold pressing process.

[0132] In some embodiments, the negative electrode active material coating may optionally include a binder. As an example, the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0133] In some embodiments, the negative electrode active material coating may optionally include a conductive agent. As an example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0134] In some embodiments, the negative electrode active material coating may also optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0135] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0136] [Positive electrode plate]

[0137] A positive electrode typically includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer including a positive electrode active material.

[0138] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0139] In some embodiments, the positive current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0140] In some embodiments, the positive electrode active material may be a known battery positive electrode active material. As an example, when the secondary battery is a lithium-ion secondary battery, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as LiNi). 1 / 3 Co 1 / 3Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0141] When the secondary battery is a sodium-ion secondary battery, as an example, the positive electrode active material of the sodium-ion secondary battery may include at least one of the following materials: sodium transition metal oxides, polyanionic compounds, and Prussian blue compounds. However, this application is not limited to these materials, and other conventionally known materials that can be used as positive electrode active materials for sodium-ion batteries may also be used.

[0142] As an optional technical solution in this application, the transition metal in the sodium transition metal oxide can be at least one selected from Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce. For example, the sodium transition metal oxide is Na. x MO2, where M is one or more of Ti, V, Mn, Co, Ni, Fe, Cr and Cu, and 0 < x ≤ 1.

[0143] As an optional technical solution in this application, the polyanionic compound can be a compound containing sodium ions, transition metal ions, or a tetrahedral (YO4) structure. n- A class of compounds with anionic units. The transition metal can be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce; Y can be at least one of P, S, and Si; n represents (YO4). n- The price state.

[0144] Polyanionic compounds can also contain sodium ions, transition metal ions, or tetrahedral (YO4) ions. n- A class of compounds containing anionic units and halide anions. The transition metal can be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce; Y can be at least one of P, S, and Si, and n represents (YO4). n- The valence state; the halogen can be at least one of F, Cl and Br.

[0145] Polyanionic compounds can also be sodium-containing tetrahedral (YO4) compounds. n- Anionic unit, polyhedral unit (ZO) y ) m+ And a class of compounds with optional halide anions. Y can be at least one of P, S, and Si, and n represents (YO4). n- The valence state; Z represents a transition metal, which can be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce; m represents (ZO) y ) m+ The valence state; the halogen can be at least one of F, Cl and Br.

[0146] Polyanionic compounds include, for example, NaFePO4, Na3V2(PO4)3 (sodium vanadium phosphate, abbreviated as NVP), Na4Fe3(PO4)2 (P2O7), NaM'PO4F (M' is one or more of V, Fe, Mn and Ni), and Na3(VO4) y )2(PO4)2F 3-2y At least one of (0≤y≤1).

[0147] Prussian blue compounds can be a class of compounds containing sodium ions, transition metal ions, and cyanide ions (CN-). The transition metal can be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce. Examples of Prussian blue compounds include Na. a Me b Me' c (CN)6, wherein Me and Me' are each independently at least one of Ni, Cu, Fe, Mn, Co and Zn, 0 < a ≤ 2, 0 < b < 1, 0 < c < 1.

[0148] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0149] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0150] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto the positive electrode current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0151] [Isolation membrane]

[0152] In some embodiments, the secondary battery also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0153] In some embodiments, the material of the separator can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0154] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0155] In some implementations, the secondary battery includes a single secondary battery cell, or a battery module and a battery pack.

[0156] In some embodiments, the secondary battery may include an outer packaging. This outer packaging may be used to encapsulate the aforementioned electrode assembly and electrolyte.

[0157] In some embodiments, the outer packaging of the secondary battery can be a hard shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the secondary battery can also be a soft pack, such as a pouch. The material of the soft pack can be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0158] This application does not impose any particular limitation on the shape of the secondary battery cell; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 1 The example shown is a square-structured secondary battery cell 5.

[0159] In some implementations, refer to Figure 2 The outer packaging may include a housing 51 and a top cover assembly 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the top cover assembly 53 can cover the opening to close the receiving cavity. The positive electrode, negative electrode, and separator can be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 52. ​​The number of electrode assemblies 52 contained in the secondary battery cell 5 can be one or more, which can be selected by those skilled in the art according to specific practical needs.

[0160] In some implementations, the secondary battery cells can be assembled into a battery module. The number of secondary battery cells contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

[0161] Figure 3 This is battery module 4, used as an example. (See reference...) Figure 3 In battery module 4, multiple secondary battery cells 5 can be arranged sequentially along the length of battery module 4. Of course, they can also be arranged in any other manner. Furthermore, these multiple secondary battery cells 5 can be fixed in place using fasteners.

[0162] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple secondary battery cells 5 are received.

[0163] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0164] Figure 4 and Figure 5 This is battery pack 1 as an example. (See reference...) Figure 4 and Figure 5 The battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3, with the upper body 2 covering the lower body 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0165] In addition, this application also provides an electrical device, which includes the secondary battery provided in this application. The secondary battery can be used as a power source for the electrical device, or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0166] As the electrical device, a single secondary battery cell, a battery module, or a battery pack can be selected according to its usage requirements.

[0167] Figure 6 This is an example of an electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of the secondary battery for this device, a battery pack or battery module can be used.

[0168] [Example]

[0169] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0170] The lithium-ion batteries in the comparative examples and embodiments were all prepared according to the following method.

[0171] (1) Preparation of positive electrode sheet

[0172] The positive electrode active material, binder polyvinylidene fluoride (PVDF), and conductive agent acetylene black were dissolved in N-methylpyrrolidone (NMP) at a mass ratio of 98:1:1 and thoroughly mixed to obtain a positive electrode slurry. The positive electrode slurry was then uniformly coated onto a positive electrode current collector, followed by drying, cold pressing, and slitting to obtain the positive electrode sheet. The compaction density of the positive electrode sheet was 3.2 g / cm³. 3 The positive electrode active material used is Li 1.05 Ni 0.5 Co 0.2 Mn 0.275 Al 0.025 The lithium-ion diffusion coefficient of O2 is 3.4 × 10⁻⁶. - 8 cm 2 / s.

[0173] (2) Preparation of negative electrode sheet

[0174] A negative electrode slurry is prepared by dissolving artificial graphite (active material), acetylene black (conductive agent), styrene-butadiene rubber (SBR) (binder), and sodium carboxymethyl cellulose (CMC) (thickener) in deionized water at a mass ratio of 96:1:2:1. The slurry is then uniformly mixed with deionized water to form a negative electrode slurry. This slurry is then uniformly coated onto a copper foil current collector, dried, and the resulting negative electrode film is cold-pressed and slit to obtain the negative electrode sheet. The porosity of the negative electrode active material coating on the electrode sheet can be controlled by adjusting the particle size of the negative electrode active material and the pressure during the cold pressing process.

[0175] (3) Preparation of electrolyte

[0176] In an argon atmosphere glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), the first and second lithium salts were dissolved in an organic solvent (EC / EMC = 3 / 7), as shown in Table 1, and stirred until homogeneous to obtain the corresponding electrolytes.

[0177] (4) Preparation of the isolation membrane: conventional polypropylene membrane is used as the isolation membrane.

[0178] (5) Preparation of lithium-ion batteries

[0179] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator positioned between the positive and negative electrodes to provide isolation. The electrodes are then wound to obtain the electrode assembly. The electrode assembly is placed in the battery casing, dried, and then injected with electrolyte. After formation and settling processes, a lithium-ion battery is obtained.

[0180] Next, the testing methods for the physical parameters and performance parameters mentioned in the embodiments of this application will be briefly introduced.

[0181] 1. Specific surface area of ​​the negative electrode active material (the specific surface area is recorded in Table 1).

[0182] The test method refers to the standard GB / T19587-2004 "Determination of specific surface area of ​​solid substances by gas adsorption BET method".

[0183] Take 8g-15g of the sample to be tested and place it into a sample tube, recording the initial mass of the sample. Place the weighed sample into the NOVA2000e testing equipment. Then begin degassing and heat the sample to 200℃, maintaining this temperature for 2 hours. Record the mass of the degassed sample afterward. Then, reload the degassed sample into the equipment and pour in liquid nitrogen for the BET test. Set the nitrogen pressure to 0.08MPa-0.12MPa and the heating temperature to 40℃-350℃. After the test, read the specific surface area from the test results.

[0184] 2. Average particle size of the negative electrode active material (recorded as average particle size Dv50 in Table 1)

[0185] In this application, the volume average particle size Dv50 of the negative electrode active material has a well-known meaning in the art and can be determined using instruments and methods known in the art. For example, it can be determined using a laser particle size analyzer (e.g., Master Size 3000) in accordance with GB / T19077-2016 Particle Size Distribution Laser Diffraction Method.

[0186] 3. Porosity of the negative electrode active material coating in the negative electrode sheet (listed as porosity in Table 1)

[0187] The porosity of the negative electrode active material coating on the negative electrode sheet was tested using an AccuPycⅡ1340 true density meter according to the instrument's instruction manual.

[0188] The battery parameters for each embodiment are shown in Table 1.

[0189] The testing process for lithium-ion batteries will be explained below.

[0190] 1. Cyclic performance test of ternary lithium-ion batteries at 25℃ / 45℃

[0191] Under constant temperature conditions of 25℃ or 45℃, the lithium-ion battery is charged at a constant current of 0.5C to a voltage of 4.4V, then charged at a constant voltage of 4.4V until the current is ≤0.05C, and then discharged at a constant current of 0.5C to a voltage of 2.5V. This constitutes one charge-discharge cycle, and the discharge capacity at this point is recorded as the discharge capacity of the battery in its first cycle. This charge-discharge cycle is repeated, and the number of cycles corresponding to when the battery retains 80% of its capacity is calculated.

[0192] The capacity retention rate (%) of a battery after N cycles at 25°C or 45°C = (discharge capacity of the battery in the Nth cycle / discharge capacity of the battery in the first cycle) × 100%.

[0193] 2. Storage performance test of ternary lithium-ion batteries at 60℃

[0194] Under a constant temperature environment of 25℃, the battery was charged to 4.4V at 0.33C and then discharged to 2.5V at 0.33C. The discharge capacity D1 was then tested. The battery was stored in a constant temperature environment of 60℃, and tested every 30 days. For each test, the battery was cooled to 25℃, charged to 4.4V at 0.33C, and then discharged to 2.5V at 0.33C. The discharge capacity was then tested. The number of storage days required for the storage capacity retention rate to decay to 80% was calculated.

[0195] The capacity retention rate (%) of a battery after being stored at 60°C for N days is calculated as follows: (Discharge capacity of the battery after N days of storage / Discharge capacity of the battery during initial storage) × 100%.

[0196] 3. Cyclic performance test of lithium iron phosphate batteries at 35℃ / 60℃

[0197] Under constant temperature conditions of 35℃ or 60℃, the lithium-ion battery is charged at a constant current of 0.5C to a voltage of 3.65V, then charged at a constant voltage of 3.65V until the current ≤0.05C, and then discharged at a constant current of 0.5C to a voltage of 2V. This constitutes one charge-discharge cycle, and the discharge capacity at this point is recorded as the discharge capacity of the battery in its first cycle. This charge-discharge cycle is repeated, and the number of cycles corresponding to 80% capacity retention is calculated. The capacity retention rate (%) after N cycles at 35℃ or 60℃ is calculated as follows: (Discharge capacity of the battery in the Nth cycle / Discharge capacity of the battery in the first cycle) × 100%.

[0198] 4. Storage performance test of lithium iron phosphate batteries at 60℃

[0199] Under a constant temperature environment of 25℃, the battery was charged at 0.33C to 3.65V, and then discharged at 0.33C to 2V, and the discharge capacity D1 was tested. The battery was stored in a constant temperature environment of 60℃, and tested every 30 days. For each test, the battery was cooled to 25℃, charged at 0.33C to 3.65V, and then discharged at 0.33C to 2V, and the discharge capacity was tested. Calculate the number of storage days required for the storage capacity retention rate to decay to 80%.

[0200] The test results are recorded in Table 2.

[0201] Table 2 Battery Test Results

[0202] Based on the data comparisons of Examples 1 to 81 and Comparative Example 4, and Examples 82 and 6, it can be seen that the addition of an acid-collecting additive to the electrolyte improves the battery's cycle performance and storage performance. Furthermore, by adjusting the concentration of the first lithium salt, the concentration of the second lithium salt, or their ratio, the battery's cycle performance and storage performance can be further improved.

[0203] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A non-aqueous electrolyte comprising a lithium salt and an acid-collecting additive, The lithium salt includes a first lithium salt and a second lithium salt, wherein the first lithium salt includes LiPF6 and the second lithium salt includes LiN(C) m F 2m+1 SO2)(C n F 2n+1 One or more of SO2, LiBF4, lithium dioxalatoborate, lithium difluorooxalatoborate, LiAsF6, and LiClO4, where m and n are each an independent natural number, and m and n can be each an independent natural number within 9. The structural formula of the acid-trapping additive includes at least one nitrogen atom with a lone pair of electrons.

2. The non-aqueous electrolyte according to claim 1, wherein, The acid-scavenging additive includes any one or more of the following: compound 1 represented by general formula (I), compound 2 represented by general formula (II), compound 3 represented by general formula (III), compound 4 represented by general formula (IV), and compound 5 represented by general formula (V). In general formula (I), Y 1 Y 2 Each is independently a C, N element, and R. 11 R 12 R 13 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 14 OH, -R 15 NR 16 R 17 -R 18 -OR 19 Any one of them, R 14 R 15 R 18 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 16 R 17 R 19 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups, and is R 16 R 17 R 19 Any carbon atom in the C1-C6 alkyl group may optionally be replaced by a heteroatom, which may be a N atom, a S atom, or a P atom, and optionally R 16 and R 17 Connect them into a ring; In general formula (II), W 1 For C, N, O or S, W 2 For C or N, W 1 and W 2 At least one of them is N; R 21 R 22 R 23 R 24 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 25 OH, -R 26 NR 27 R 28 -R 29 -OR 30 Any one of them, R 25 R 26 R 29 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 27 R 28 R 30 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups; In general formula (III), A 1 A 2 A 3 A 4 A 5 A 6 A 7 Each can be independently represented by C or N, with A as an option. 1 Let N be the number of elements, and A be the number of elements. 2 A 3 A 4 A 5 A 6 A 7 Each is independently C or N; R 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be a hydrogen atom, a C1-C6 alkyl group, a C2-C6 alkenyl group, a C2-C6 alkynyl group, -OH, or -R. 38 NR 39 R 40 Any one of alkoxy groups, R 38 Selected from any one of C0-C6 alkylene and C2-C6 alkenyl groups, R 39 R 40 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups; In general formula (IV), X 1 X 2 X 3 Each of them is independently C or N, and at least one of them must be N. a and b are each independently integers between 0 and 3. 41 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 42 OH, -R 43 NR 44 R 45 -R 46 -OR 47 Any one of them, R 42 R 43 R 46 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 44 R 45 R 47 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups; In the general formula (V), V 1 V 2 V 3 Each is independently C or N, and at least one must be N, d is an integer from 0 to 3, and each R 51 Each is independently selected from hydrogen atoms, halogen atoms, C1-C6 alkyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, and -R groups. 52 OH, -R 53 NR 54 R 55 -R 56 -OR 57 Any one of them, R 52 R 53 R 56 Each is independently selected from any one of C0-C6 alkylene or C2-C6 alkenyl groups, R 54 R 55 R 57 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C6 alkyl groups, and C1-C6 haloalkyl groups.

3. The non-aqueous electrolyte according to claim 2, wherein, In general formula (I), the R 11 R 12 R 13 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 14 OH, -R 15 NR 16 R 17 -R 18 -OR 19 Any one of them, R 14 R 15 R 18 Each is independently selected from any one of the C0-C3 alkylene groups, R 16 R 17 R 19 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C3 alkyl groups, and C1-C3 haloalkyl groups, and is used as said R. 16 R 17 R 19 Any carbon atom in the C1-C6 alkyl group may optionally be replaced by a heteroatom, said heteroatom being a nitrogen atom, and said R may optionally be... 16 and R 17 They connect to form 5-membered or 6-membered alicyclic rings.

4. The non-aqueous electrolyte according to claim 2, wherein, The R 11 R 12 R 13 Each is independently selected from hydrogen atoms, halogen atoms, methyl, ethyl, n-propyl, isopropyl, allyl, propargyl, -OH, -CH3OH, -NH2, -CH2NH2, -N(CH3)2, O-CH3, Any one of them; optionally, the R 11 R 12 R 13 Each is independently selected from hydrogen atom, F atom, methyl, ethyl, n-propyl, isopropyl, -CH3OH, -CH2NH2, -N(CH3)2, O-CH3, Any one of them.

5. The non-aqueous electrolyte according to claim 2, wherein, The compound having the structure shown in general formula (III) is selected from any one or more of the following compounds:

6. The non-aqueous electrolyte according to claim 2, wherein, The general formula (II) has one or more of the following characteristics: 1) In general formula (II), the W 1 For N, W 2 It can be C or N; 2) The R 21 R 22 R 23 R 24 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 25 OH, -R 26 NR 27 R 28 -R 29 -OR 30 Any one of them, R 25 R 26 R 29 Each is independently selected from any one of the C0-C4 alkylene groups, R 27 R 28 R 30 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C4 alkyl groups, and C1-C4 haloalkyl groups.

7. The non-aqueous electrolyte according to claim 2 or 6, wherein, The R 21 R 22 R 23 R 24 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, propyl, cyclopropyl, allyl, propyne, -OH, -CH3OH, -NH2, -NHCH3, -CH2NH2, -N(CH3)2, O-CH3.

8. The non-aqueous electrolyte according to claim 2 or 6, wherein, The R 21 R 22 R 23 R 24 Each is independently selected from any one of hydrogen atom, F atom, methyl, propyl, cyclopropyl, allyl, -CH3OH, -NH2, -NHCH3, -N(CH3)2.

9. The non-aqueous electrolyte according to claim 2, wherein, The compound having the structure shown in general formula (II) is selected from any one or more of the following compounds:

10. The non-aqueous electrolyte according to claim 2, wherein, The general formula (III) has one or more of the following characteristics: 1) In general formula (III), A 1 For N, A 2 A 3 A 4 A 5 A 6 A 7 Each can be independently represented as C or N; 2)R 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be a hydrogen atom, a C1-C4 alkyl group, a C2-C4 alkenyl group, a C2-C4 alkynyl group, -OH, or -R. 38 NR 39 R 40 Any one of alkoxy groups, R 38 Selected from any one of C0-C3 alkylene groups, R 39 R 40 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C3 alkyl groups, and C1-C3 haloalkyl groups.

11. The non-aqueous electrolyte according to claim 2 or 10, wherein, R 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be any one of hydrogen atom, methyl, ethyl, allyl, propyne, -OH, -NH2, -CH2NH2, -N(CH3)2, and O-CH3.

12. The non-aqueous electrolyte according to claim 2 or 10, wherein, R 31 R 32 R 33 R 34 R 35 R 36 R 37 It can be any one of hydrogen atom, methyl, ethyl, or O-CH3.

13. The non-aqueous electrolyte according to claim 2, wherein, The compound having the structure shown in general formula (III) is selected from any one or more of the following compounds:

14. The non-aqueous electrolyte according to claim 2, wherein, The general formula (IV) has one or more of the following characteristics: 1) In the general formula (IV), X 1 Let N, X 2 X 3 Each can be independently represented as C or N; 2) a and b are each independently 0, 1 or 2.

15. The non-aqueous electrolyte according to claim 2 or 14, wherein, Each R 41 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 42 OH, -R 43 NR 44 R 45 -R 46 -OR 47 Any one of them, R 42 R 43 R 46 Each is independently selected from any one of the C0-C3 alkylene groups, R 44 R 45 R 47 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C4 alkyl groups, and C1-C4 haloalkyl groups.

16. The non-aqueous electrolyte according to claim 2 or 14, wherein, Each R 41 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, hydroxyl, -NH2, -N(CH3)2.

17. The non-aqueous electrolyte according to claim 2, wherein, The compound having the structure shown in general formula (IV) is selected from any one or more of the following compounds:

18. The non-aqueous electrolyte according to claim 2, wherein, The general formula (V) has one or more of the following characteristics: 1) In the general formula (V), d is 0 or 1; 2) Each R 51 Each is independently selected from hydrogen atoms, halogen atoms, C1-C4 alkyl groups, C3-C5 alkenyl groups, C3-C5 alkynyl groups, and -R groups. 52 OH, -R 53 NR 54 R 55 -R 56 -OR 57 Any one of them, R 52 R 53 R 56 Each is independently selected from any one of the C0-C3 alkylene groups, R 54 R 55 R 57 Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C4 alkyl groups, and C1-C4 haloalkyl groups.

19. The non-aqueous electrolyte according to claim 2 or 18, wherein, Each R 51 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, n-propyl, isopropyl, hydroxyl, -NH2, -N(CH3)2.

20. The non-aqueous electrolyte according to claim 2 or 18, wherein, Each R 51 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, n-propyl, and isopropyl.

21. The non-aqueous electrolyte according to claim 2, wherein, The compound having the structure shown in general formula (V) is selected from any one or more of the following compounds:

22. The non-aqueous electrolyte according to any one of claims 1 to 21, wherein, The acid-collecting additive has a mass percentage of W3 in the non-aqueous electrolyte, where W3 satisfies 0.01% ≤ W3 ≤ 20%.

23. The non-aqueous electrolyte according to claim 22, wherein, 0.05% ≤ W3 ≤ 10%, or 0.5% ≤ W3 ≤ 5%.

24. The non-aqueous electrolyte according to any one of claims 1 to 23, wherein, The first lithium salt or the second lithium salt has one or more of the following technical features: 1) The second lithium salt includes any one or more of Li(FSO2)2N, Li(CF3SO2)(FSO2)N, Li(CF3SO2)2N, Li(C2F5SO2)2N, and Li(CF3SO2)(C2F5SO2)N; 2) The concentration range C1 of the first lithium salt in the non-aqueous electrolyte satisfies 0.1 mol / L ≤ C1 ≤ 1.5 mol / L; or satisfies 0.2 mol / L ≤ C1 ≤ 1.2 mol / L; 3) The concentration range C2 of the second lithium salt in the non-aqueous electrolyte satisfies 0.1 mol / L ≤ C2 ≤ 1.5 mol / L, or 0.2 mol / L ≤ C2 ≤ 1 mol / L; 4) The concentration range of the lithium salt in the non-aqueous electrolyte is 0.5 mol / L to 2.5 mol / L, or the concentration range of the lithium salt in the non-aqueous electrolyte is 0.8 mol / L to 2 mol / L; 5) The molar ratio of the first lithium salt to the second lithium salt is 5:1 to 1:6; or the molar ratio of the first lithium salt to the second lithium salt is 3.5:1 to 1:

5.

25. A secondary battery, comprising a positive electrode, a negative electrode, and an electrolyte, wherein, The electrolyte is the non-aqueous electrolyte according to any one of claims 1 to 24.

26. The secondary battery according to claim 25, wherein, The negative electrode sheet includes a negative electrode active material, and the negative electrode active material satisfies one or two of the following conditions: 1) The BET specific surface area of ​​the negative electrode active material is 0.5 m². 2 / g-2.0m 2 / g, or 0.8m 2 / g-1.5m 2 / g; 2) The volume average particle size Dv50 of the negative electrode active material is controlled within 3μm≤Dv50≤50μm, or 5μm≤Dv50≤30μm, or 12μm≤Dv50≤25μm.

27. The secondary battery according to claim 25 or 26, wherein, The negative electrode sheet includes a negative current collector and a negative active material coating disposed on one or both sides of the negative current collector, wherein the porosity of the negative active material coating is 30% to 45%.

28. An electrical device comprising a secondary battery, wherein, The secondary battery includes the secondary battery as described in any one of claims 25 to 27.

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