Secondary battery and electric device

Abstract

The invention provides a secondary battery and an electric device. The secondary battery comprises a positive pole piece and a non-aqueous electrolyte, a positive active material in the positive pole piece has a chemical formula of Li (alpha) Ni (x) < 1 > Co (y) < 1 > Mn (z) < 1 > M (1-x-y-z) < 1 > O < 2 + beta >, alpha lt; 1, 2, 0 lt; beta < lt >; 0, 0.1, 0.45 lt; x1lt; 1, 0lt; y < 1lt >; 0, 0, 0.3, 0; z1lt; z1t; 0.5 part; m is one or more of Ti, Al, Zr, Mg, Y, La, Sr, Zn, Ba, W, Nb, Mo and B, the non-aqueous electrolyte comprises an organic solvent and an organic alkali additive, the organic alkali additive comprises any one or more of 5-12-membered aromatic heterocyclic organic alkali or 5-12-membered aliphatic heterocyclic organic alkali, the 5-12-membered aromatic heterocyclic organic alkali and 5-12-membered aliphatic heterocyclic organic alkali, and the ring structure in the organic alkali contains nitrogen atoms. And the organic alkali additive can prolong the cycle life of the secondary battery.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to a secondary battery and an electrical device using the same. Background Art

[0002] In recent years, with the continuous growth of the portable electronic device, electric vehicle, and large-scale energy storage markets, the demand for lithium-ion batteries has been increasing. As a key component of lithium-ion batteries, cathode materials have higher requirements for their safety performance and cost while focusing on high energy density. Lithium iron manganese phosphate has a relatively high voltage platform and energy density, and also has the characteristics of low cost, environmental friendliness, and high safety performance of lithium iron phosphate, thus receiving extensive attention.

[0003] With the rapid rise of the electric vehicle industry, high-energy-density lithium-ion batteries have developed rapidly. However, the current existing lithium iron phosphate batteries have a low capacity and can no longer meet the requirements of high cruising range for power batteries. The ternary materials have a higher capacity and can meet the requirements of high cruising range, so ternary materials have become the main research direction of current cathode materials for power batteries. However, during the charging process, the bond strength between the lattice oxygen on the surface of ternary materials and the surrounding transition metals decreases, forming unstable interfacial oxygen that accelerates the oxidation and decomposition of the electrolyte. The decomposition products deposit on the surfaces of the positive and negative electrodes, increasing the battery impedance, and further deteriorating the storage and cycling performance of the battery cells. In addition, the release of unstable lattice oxygen will lead to the destruction of the cathode structure, a decrease in cycling performance, and an increase in safety hazards. Summary of the Invention

[0004] This application provides a secondary battery and an electrical device using the same to improve the cycling performance of the secondary battery.

[0005] In a first aspect of this application, a secondary battery is provided, including a positive electrode plate and a non-aqueous electrolyte. The positive active material in the positive electrode plate has the chemical formula Li ɑ Ni x1 Co y1 Mn z1 M 1-x1-y1-z1 O 2+β , where 0.8 < ɑ < 1.2, 0 < β < 0.1, 0.45 < x1 < 1, 0 < y1 < 0.3, 0 < z1 < 0.5; M is one or more of Ti, Al, Zr, Mg, Y, La, Sr, Zn, Ba, W, Nb, Mo, B. The non-aqueous electrolyte includes an organic solvent and an organic base additive. The organic base additive includes any one or more of a 5-12 member aromatic heterocyclic organic base or a 5-12 member aliphatic heterocyclic organic base. The ring structures of the 5-12 member aromatic heterocyclic organic base and the 5-12 member aliphatic heterocyclic organic base contain nitrogen atoms.

[0006] Organic base additives in non-aqueous electrolytes preferentially oxidize and polymerize on the surface of the positive electrode active material to form a NO double layer interface, which stabilizes the surface of the positive electrode active material and prevents lattice oxygen from escaping from the lattice and damaging the positive electrode structure. At the same time, the NO double layer interface has a certain electronegativity, which prevents the solvent from further oxidizing on the surface of the positive electrode active material and inhibits the resulting side reactions in the electrolyte, thereby extending the cycle life of the secondary battery.

[0007] In any embodiment of the first aspect of this application, the 5-12-membered aromatic heterocyclic organic base includes compound 1 represented by general formula (I), compound 2 represented by general formula (II), or compound 3 represented by general formula (III); the 5-12-membered alicyclic organic base includes any one or more of compound 4 represented by general formula (IV) or compound 5 represented by 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 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 40Each 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 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.

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

[0016] In any embodiment of the first aspect of this application, general formula (II) has any one or more of the following features: 1)W1 For N, W 2 It can be C or N; 2)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.

[0017] In any embodiment of the first aspect of this application, in general formula (II), 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.

[0018] In any embodiment of the first aspect of this application, in general formula (II), 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.

[0019] In any embodiment of the first aspect of this application, the compound having the structure shown in general formula (II) is selected from any one or more of the following compounds:

[0020] In any embodiment of the first aspect of this application, general formula (III) has any one or more of the following features: 1)A 1 For N, A 2 A3 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.

[0021] In any embodiment of the first aspect of this application, in general formula (III), 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.

[0022] In any embodiment of the first aspect of this application, in general formula (III), 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.

[0023] In any embodiment of the first aspect of this application, the compound having the structure shown in general formula (III) is selected from any one or more of the following compounds:

[0024] In any embodiment of the first aspect of this application, general formula (IV) has any one or more of the following features: 1)X1 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; 3) 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.

[0025] In any embodiment of the first aspect of this application, in general formula (IV), each R 41 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, hydroxyl, -NH2, -N(CH3)2.

[0026] In any embodiment of the first aspect of this application, the compound having the structure shown in general formula (IV) is selected from any one or more of the following compounds:

[0027] In any embodiment of the first aspect of this application, the general formula (V) has any one or more of the following features: 1) 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 57Each is independently selected from any one of hydrogen atoms, halogen atoms, C1-C4 alkyl groups, and C1-C4 haloalkyl groups.

[0028] In any embodiment of the first aspect of this application, in general formula (V), 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.

[0029] In any embodiment of the first aspect of this application, in general formula (V), each R 51 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, n-propyl, and isopropyl.

[0030] In any embodiment of the first aspect of this application, in general formula (V), the compound having the structure shown in general formula (V) is selected from any one or more of the following compounds:

[0031] In any embodiment of the first aspect of this application, the mass percentage of the organic base additive in the non-aqueous electrolyte is W1, wherein 0.01% ≤ W1 ≤ 20%.

[0032] In any embodiment of the first aspect of this application, 0.05% ≤ W1 ≤ 10%, or 0.5% ≤ W1 ≤ 5%.

[0033] In any embodiment of the first aspect of this application, the surface of the positive electrode active material has a fast ion conductor coating layer.

[0034] In any embodiment of the first aspect of this application, the fast ion conductor coating layer has one or more of the following features: 1) The fast ion conductor in the fast ion conductor coating layer has the chemical formula Li 3x2 La 2 / 3-x2 M' a1 TiN z1 O3, Li 2+ 2x3 Zn 1-x3 XO4 or Li 1+x4 M”2(PO4)3, where M' is Ba 2+ and / or Sr 2+ N is Al 3+ and / or Zr 4+ , 0.04≤x2≤0.167, 0≤a1≤1, 0≤z1≤1; X is Al, S, Si, Ge, Ti and P, -0.3<x3<0.8; M” is one or more of Al, Zr, Ti, Ge, Hf and Ti, 0≤x4≤0.5; 2) The fast ion conductor coating layer accounts for 0.1%-0.5% of the total mass of the cathode material; 3) The ion diffusion coefficient of the cathode material with a fast ion conductor coating is 10. -9 -10 -6 cm 2 / s.

[0035] In any embodiment of the first aspect of this application, the fast ion conductor has the chemical formula Li. 3x2 La 2 / 3-x2 TiO3, Li 2+2x3 Zn 1-x3 GeO4, Li 1+x4 Al x4 Ti 2-x4 (PO3)4 or Li 1+x4 Al x4 Ge 2-x4 (PO3)4, 0.04≤x2≤0.115, 0<x3<0.5, 0.3≤x4≤0.5.

[0036] In any embodiment of the first aspect of this application, the compaction density of the positive electrode film layer in the positive electrode sheet is 2.5 / cm². 3 -3.7g / cm 3 Prioritize controlling it at 2.8 / cm. 3 -3.6 / cm 3 .

[0037] The second aspect of this application provides an electrical device including a secondary battery, which includes the secondary battery provided in any embodiment of the first aspect described above. Attached Figure Description

[0038] 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.

[0039] Figure 1 This is a schematic diagram of a secondary battery according to one embodiment of this application.

[0040] Figure 2 yes Figure 1 An exploded view of a secondary battery according to one embodiment of this application is shown.

[0041] Figure 3 This is a schematic diagram of a battery module according to one embodiment of this application.

[0042] Figure 4This is a schematic diagram of a battery pack according to one embodiment of this application.

[0043] Figure 5 yes Figure 4 An exploded view of a battery pack according to one embodiment of this application is shown.

[0044] 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.

[0045] The accompanying drawings are not drawn to scale.

[0046] Explanation of reference numerals in the attached figures:

[0047] 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

[0048] 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.

[0049] The embodiments of the secondary battery and power-consuming device of this application are hereby disclosed in detail with appropriate reference to the accompanying drawings. However, unnecessary detailed descriptions 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 making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0050] 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.

[0051] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0052] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0053] 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.

[0054] 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.

[0055] 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).

[0056] [Secondary battery]

[0057] A secondary battery, also known as a rechargeable battery or a storage battery, refers to a battery that can be activated by charging after discharging so that it can be used continuously.

[0058] Generally, a secondary battery includes a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. During the charge and discharge process of the battery, active ions (such as lithium ions) intercalate and deintercalate between the positive electrode plate and the negative electrode plate. The separator is disposed between the positive electrode plate and the negative electrode plate, mainly to prevent short circuit between the positive and negative electrodes, and at the same time allows active ions to pass through. The electrolyte is between the positive electrode plate and the negative electrode plate, mainly to conduct active ions.

[0059] The first embodiment of this application provides a secondary battery, including a positive electrode plate and a non-aqueous electrolyte. The positive active material in the positive electrode plate has the chemical formula Li ɑ Ni x1 Co y1 Mn z1 M 1-x1-y1-z1 O 2+β , where 0.8 < ɑ < 1.2, 0 < β < 0.1, 0.45 < x1 < 1, 0 < y1 < 0.3, 0 < z1 < 0.5; M is one or more of Ti, Al, Zr, Mg, Y, La, Sr, Zn, Ba, W, Nb, Mo, B. The non-aqueous electrolyte includes an organic solvent and an organic base additive. The organic base additive includes any one or more of a 5-12 member aromatic heterocyclic organic base or a 5-12 member aliphatic heterocyclic organic base. The ring structures of the 5-12 member aromatic heterocyclic organic base and the 5-12 member aliphatic heterocyclic organic base contain nitrogen atoms.

[0060] The organic base additive in the non-aqueous electrolyte of this application preferentially oxidatively polymerizes on the surface of the positive active material to form an N-O double-layer interface, which plays a role in stabilizing the surface of the positive active material, thereby preventing lattice oxygen from escaping from the lattice and damaging the positive electrode structure. At the same time, the N-O double-layer interface has a certain electronegativity, blocking the further oxidation of the solvent on the surface of the positive active material and inhibiting the side reactions of the electrolyte caused thereby, thereby prolonging the cycle life of the secondary battery.

[0061] [Non-aqueous electrolyte]

[0062] The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific restrictions on the type of electrolyte; it can be selected according to requirements.

[0063] In some embodiments of this application, the aforementioned 5-12-membered aromatic heterocyclic organic bases include compound 1 represented by general formula (I), compound 2 represented by general formula (II), or compound 3 represented by general formula (III); the 5-12-membered alicyclic organic bases include any one or more of compound 4 represented by general formula (IV) or compound 5 represented by general formula (V).

[0064] 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;

[0065] 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 24Each 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;

[0066] 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;

[0067] In general formula (IV), X 1 X 2 X3 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.

[0068] 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.

[0069] The above-mentioned general formula compounds exhibit good dispersibility and stability in electrolytes, and can form a more stable NO double layer interface, further improving battery cycle performance.

[0070] In some embodiments of this application, in general formula (I), R 11 R 12 R13 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.

[0071] In some embodiments of this application, 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.

[0072] In some embodiments of this application, compounds having the structure shown in general formula (III) are selected from any one or more of the following compounds:

[0073]

[0074] In some embodiments of this application, general formula (II) has any one or more of the following features:

[0075] 1) The W 1 For N, W 2 It can be C or N;

[0076] 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.

[0077] In some embodiments of this application, in general formula (II), 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.

[0078] In some embodiments of this application, in general formula (II), 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.

[0079] In some embodiments of this application, compounds having the structure shown in general formula (II) are selected from any one or more of the following compounds:

[0080]

[0081] In some embodiments of this application, general formula (III) has any one or more of the following features:

[0082] 1)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.

[0083] 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.

[0084] In some embodiments of this application, in general formula (III), 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.

[0085] In some embodiments of this application, in general formula (III), 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.

[0086] In some embodiments of this application, compounds having the structure shown in general formula (III) are selected from any one or more of the following compounds:

[0087]

[0088] In some embodiments of this application, general formula (IV) has any one or more of the following features:

[0089] 1)X 1 Let N, X 2 X 3 Each can be independently represented as C or N;

[0090] 2) a and b are each independently 0, 1, or 2;

[0091] 3) 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.

[0092] In some embodiments of this application, in general formula (IV), each R 41 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, hydroxyl, -NH2, -N(CH3)2.

[0093] In some embodiments of this application, compounds having the structure shown in general formula (IV) are selected from any one or more of the following compounds:

[0094]

[0095] In some embodiments of this application, the general formula (V) has any one or more of the following features:

[0096] 1) d is 0 or 1;

[0097] 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, -R53 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.

[0098] In some embodiments of this application, in general formula (V), 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;

[0099] In some embodiments of this application, in general formula (V), each R 51 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, n-propyl, and isopropyl.

[0100] In some embodiments of this application, in general formula (V), the compound having the structure shown in general formula (V) is selected from any one or more of the following compounds:

[0101]

[0102] In some embodiments of this application, the mass percentage of organic base additives in the non-aqueous electrolyte is W1, wherein 0.01% ≤ W1 ≤ 20%, for example, 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 3%, 5%, 10%, 15%, or 20%; optionally, 0.05% ≤ W1 ≤ 10%, or 0.5% ≤ W1 ≤ 5%. Controlling the content of organic base additives is beneficial on the one hand for fully protecting the positive electrode active material, and on the other hand for avoiding a decrease in the conductivity of the non-aqueous electrolyte due to excessive dosage.

[0103] In some embodiments, the organic solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0104] In some embodiments, the electrolyte further includes an electrolyte salt. In some embodiments, the electrolyte salt may be selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, or LiN(C). x F 2x+1 SO2)(C y F 2y+ The electrolyte salt comprises at least one of the following: lithium trifluoromethanesulfonylimide (where x and y are natural numbers, such as lithium trifluoromethanesulfonate), lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate. In some embodiments, the concentration range of the above electrolyte salt is 0.5 mol / L to 2.5 mol / L, preferably 0.8 mol / L to 2 mol / L.

[0105] 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 aforementioned other 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.

[0106] [Positive electrode plate]

[0107] 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.

[0108] 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.

[0109] In some embodiments of this application, the surface of the positive electrode active material has a fast ion conductor coating layer. The fast ion conductor coating the positive electrode active material has good lithium-ion conductivity, thus increasing the migration rate of lithium ions on the surface of the positive electrode active material. This facilitates the insertion and extraction of lithium ions during charging and discharging, improving the material's initial discharge specific capacity and initial coulombic efficiency. Furthermore, the fast ion conductor coating layer effectively prevents direct contact between the material surface and the electrolyte, suppressing side reactions and thereby improving the cycle and storage performance of the positive electrode active material.

[0110] In some embodiments of this application, the fast ion conductor coating layer has one or more of the following characteristics:

[0111] 1) The fast ion conductor in the fast ion conductor coating layer has the chemical formula Li 3x2 La 2 / 3-x2 M' a1 TiN z1 O3, Li 2+ 2x3 Zn 1-x3 XO4 or Li 1+x4 M”2(PO4)3, where M' is Ba 2+ and / or Sr 2+ N is Al 3+ and / or Zr 4+ , 0.04≤x2≤0.167, 0≤a1≤1, 0≤z1≤1; X is Al, S, Si, Ge, Ti and P, -0.3<x3<0.8; M” is one or more of Al, Zr, Ti, Ge, Hf and Ti, 0≤x4≤0.5;

[0112] 2) The fast ion conductor coating layer accounts for 0.1%-0.5% of the total mass of the cathode material;

[0113] 3) The ion diffusion coefficient of the cathode material having the fast ion conductor coating layer is 10. -9 -10 -6 cm 2 / s.

[0114] The fast ion conductor coating layer within the above-mentioned mass content range can achieve high-quality coating of the positive electrode active material, which can fully improve the lithium ion migration rate and fully suppress interfacial side reactions, while maintaining the high conductivity and high specific capacity of the positive electrode active material.

[0115] In some embodiments of this application, the fast ion conductor has the chemical formula Li. 3x2 La 2 / 3-x2 TiO3, Li 2+ 2x3 Zn 1-x3 GeO4, Li 1+x4 Al x4 Ti 2-x4 (PO3)4, 0.04≤x2≤0.115, 0<x3<0.5, 0.3≤x4≤0.5. These fast ion conductors more effectively prevent direct contact between the material surface and the electrolyte, suppressing side reactions and thus better improving the cycle and storage performance of the positive electrode active material.

[0116] In some embodiments, the aforementioned fast ion conductor Li 3x2 La2 / 3-x2 TiO3 exemplarily includes Li 0.2 La 0.6 TiO3, Li 0.33 La 0.56 TiO3, etc.; the above-mentioned fast ion conductor Li 2+2x3 Zn 1-x3 GeO4 exemplarily includes Li3Zn 0.5 GeO4, etc.; the above-mentioned fast ion conductor Li 1+x4 Al x4 Ti 2-x4 (PO3)4 exemplarily includes Li 1.5 Al 0.5 Ti 1.5 (PO4)3, etc.; the above-mentioned fast ion conductor Li 1+ x4 Al x4 Ge 2-x4 (PO3)4 exemplarily includes Li 1.5 Al 0.5 Ge 1.5 (PO4)3, etc.

[0117] The cathode material with a fast-ion conductor coating layer described in this application can be prepared using known materials or known methods. This application uses Li as the fast-ion conductor coating layer. 0.2 La 0.6 TiO3 fast ion coating, Li3Zn 0.5 GeO4 fast ion coating or Li 1.5 Al 0.5 Ge 1.5 The preparation method of the cathode material of fast ion conductor coating is illustrated by taking (PO4)3 fast ion conductor coating as an example.

[0118] Li 0.2 La 0.6 Preparation of TiO3 fast ion coated cathode material: Tetrabutyl titanate, lanthanum nitrate, and lithium nitrate were added sequentially to ethanol in a molar ratio of 1:0.6:0.2, and stirred for about 30 minutes until completely dissolved. The solution was then heated to 60°C in a water bath with continuous stirring to evaporate the organic solvent. The resulting solid powder was dried in a vacuum oven for 12 hours, and finally sintered at 600°C for 4 hours to obtain Li. 0.2 La 0.6 TiO3 material. The obtained Li 0.2 La 0.6 TiO3 was uniformly mixed with the cathode material and sintered in oxygen at 600°C for 5 hours to obtain Li. 0.2 La 0.6 TiO3-coated cathode material.

[0119] Li3Zn 0.5 Preparation of GeO4 fast ion coated cathode material: Li2CO3, ZnO, and GeO2 were reacted in a platinum crucible at 1300℃ in a molar ratio of 3:1:2, followed by sintering at 800℃ for 4 h to obtain Li3Zn 0.5 GeO4. The resulting Li3Zn 0.5 GeO4 was uniformly mixed with the cathode material and sintered in oxygen at 600°C for 5 hours to obtain Li3Zn. 0.5 GeO4-coated cathode material.

[0120] Li 1.5 Al 0.5 Ge 1.5 Preparation of (PO4)3 fast ion conductor-coated cathode material: Based on Li 1.5 Al 0.5 Ge 1.5 The chemical formula (PO4)3 is determined by the following proportions: GeO2, LiOH·H2O, NH4H2PO4, Al(NO3)3·9H2O, citric acid monohydrate, and ethylene glycol. The molar ratio of citric acid to the metal cation must be 1:1.5, and the molar ratio of citric acid to ethylene glycol must be 1:1. The following is a list of ingredients: GeO2, LiOH·H2O, NH4H2PO4, Al(NO3)3·9H2O, C6H... 10 O8 and (CH2OH)2 were added sequentially to an aqueous solution, heated and stirred at 80°C for 5 hours, and then placed in an oven at 170°C for 24 hours. The resulting solid powder was sintered at 800°C for 2 hours to obtain a fast ion conductor. The obtained Li 1.5 Al 0.5 Ge 1.5 (PO4)3 was uniformly mixed with the cathode material and sintered in oxygen at 600°C for 5 hours to obtain Li. 1.5 Al 0.5 Ge 1.5 (PO4)3 coated cathode material.

[0121] Excessive compaction density of the positive electrode film layer can easily cause particle structure breakage or cracks. The exposed fresh interface will undergo side reactions with the electrolyte, accelerating cell degradation and reducing battery life and safety performance. Conversely, insufficient compaction density of the positive electrode film layer results in loose contact between particles, and some particles may be unable to receive current, causing capacity loss. In this application, the compaction density of the positive electrode film layer in the positive electrode sheet can be referenced to the compaction density of conventional positive electrode films. In some embodiments, the compaction density of the positive electrode film layer in the positive electrode sheet is 2.5 / cm². 3 -3.7g / cm 3 Prioritize controlling it at 2.8 / cm. 3 -3.6 / cm 3This allows for further improvement in space utilization, which is beneficial for maximizing the specific capacity of the positive electrode active material. When preparing the positive electrode film using the same material, the electrode can be pressed to a pre-designed thickness by adjusting the roller pressing pressure, thus obtaining different compaction densities for the positive electrode film.

[0122] 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.).

[0123] 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.

[0124] 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.

[0125] 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.

[0126] [Negative electrode plate]

[0127] The negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector, the negative electrode film layer including a negative electrode active material.

[0128] 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.

[0129] 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.).

[0130] 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.

[0131] In some embodiments, the negative electrode film layer 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).

[0132] In some embodiments, the negative electrode film 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.

[0133] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0134] 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.

[0135] [Isolation membrane]

[0136] 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.

[0137] 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.

[0138] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0139] In some implementations, the secondary battery includes a single secondary battery cell, or a battery module and a battery pack.

[0140] In some embodiments, the secondary battery may include an outer packaging. This outer packaging may be used to encapsulate the electrode assembly and electrolyte described above.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] Optionally, the battery module 4 may also include a housing with a receiving space in which multiple secondary battery cells 5 are received.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] As the electrical device, a single secondary battery cell, a battery module, or a battery pack can be selected according to its usage requirements.

[0151] 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.

[0152] [Example]

[0153] 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.

[0154] The composition of the positive electrode active material in the positive electrode sheet in the following embodiments is recorded in Table 1. When the positive electrode active material has a fast ion conductor coating layer, the preparation method of the positive electrode material coated with the fast ion conductor is as described above, and will not be repeated in the embodiments.

[0155] The lithium-ion batteries in the comparative examples and embodiments were all prepared according to the following method.

[0156] (1) Preparation of positive electrode sheet

[0157] The positive electrode active material, binder polyvinylidene fluoride (PVDF), and conductive agent acetylene black are dissolved in solvent N-methylpyrrolidone (NMP) at a mass ratio of 98:1:1. After thorough stirring and mixing, a positive electrode slurry is obtained. The positive electrode slurry is then uniformly coated onto the positive electrode current collector, and after drying, cold pressing, and slitting, a positive electrode sheet is obtained.

[0158] (2) Preparation of negative electrode sheet

[0159] The active material is artificial graphite (average particle size Dv50 of 14 μm and BET specific surface area of ​​1.2 m²). 2 The negative electrode slurry is prepared by dissolving the conductive agent acetylene black, the binder styrene-butadiene rubber (SBR), and the thickener sodium carboxymethyl cellulose (CMC) in deionized water at a mass ratio of 96:1:2:1. The negative electrode slurry is then uniformly mixed with the deionized water to prepare a negative electrode slurry. The negative electrode slurry is then uniformly coated on the negative electrode current collector copper foil, dried to obtain a negative electrode film, and then cold-pressed and slit to obtain a negative electrode sheet. The porosity of the negative electrode active material coating in the negative electrode sheet is 40%.

[0160] (3) Preparation of electrolyte

[0161] In an argon atmosphere glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), 0.7 mol / L LiPF6 and 0.6 mol / L LiFSI (organic base additives, if present, otherwise not) were dissolved in an organic solvent (EC / EMC = 3 / 7), as shown in Table 1. The mixture was stirred until homogeneous to obtain the corresponding electrolyte.

[0162] (4) Preparation of the isolation membrane: conventional polypropylene membrane is used as the isolation membrane.

[0163] (5) Preparation of lithium-ion batteries

[0164] 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.

[0165] test

[0166] 1. Compacted density of the positive electrode sheet

[0167] Positive electrode sheets with a diameter of 14mm were punched out using a stamping machine. The mass (mc) and thickness (dc) of the positive electrode sheets were measured using an electronic balance and a benchtop digital thickness gauge, respectively. A sufficient number of aluminum foil substrates with a diameter of 14mm were punched out using a stamping machine. The mass (m) of the aluminum foil substrates was measured using an electronic balance and a benchtop digital thickness gauge, respectively. Al Thickness d Al .

[0168] Positive electrode compaction density

[0169] Where: ρ c This refers to the compaction density of the positive electrode sheet, expressed in grams per cubic centimeter (g / cm³). 3 );

[0170] m c The value represents the mass of the positive electrode, expressed in grams (g).

[0171] m Al The mass of the aluminum foil substrate is expressed in grams (g).

[0172] The diameter of the positive electrode is expressed in millimeters (mm).

[0173] d c The thickness of the positive electrode is expressed in micrometers (μm).

[0174] d Al The thickness of the aluminum foil substrate is expressed in micrometers (μm).

[0175] 2. Ion diffusion coefficient test of positive electrode active material

[0176] The ion diffusion coefficient was determined using a constant current intermittent titration method; the formula for constant current intermittent titration is shown below:

[0177] τ is the relaxation time, n m Vm is the number of moles, S is the electrode / electrolyte contact area, ΔEs is the total voltage change caused by the pulse, and ΔEt is the voltage change during constant current charging / discharging.

[0178] The battery fabrication parameters for each embodiment and comparative example are recorded in Table 1.

[0179] Performance testing

[0180] 1. Lithium-ion battery 25℃ / 45℃ cycle performance test

[0181] 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.

[0182] 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%.

[0183] 2. Lithium-ion battery storage performance test at 60℃

[0184] 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.

[0185] 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%.

[0186] 3. First-cycle capacity and first-cycle efficiency of lithium-ion batteries

[0187] At 25℃, a lithium-ion battery was charged at a constant current of 0.33C to 4.4V, then charged at a constant voltage of 4.4V until the current ≤0.05C, and its actual charging capacity was recorded as C0. The lithium-ion battery was then discharged at a constant current of 0.33C to 2.5V, and its actual capacity was recorded as D0 (mAh). The specific capacity of the lithium-ion battery is D0 / W3 (mAh / g), where W3 is the mass (g) of the positive electrode active material; the first-cycle efficiency of the lithium-ion battery is D0 / C0 (%).

[0188] The test results are recorded in Table 2 and Table 3.

[0189] Table 2

[0190] Table 3 Group First discharge capacity (mAh / g) First Coulomb Efficiency % Comparative Example 1 177 86.5 Comparative Example 4 179 86.8 Example 1 178 86.7 Example 7 189 87.7 Example 47 182 87.3 Example 48 185 87.4 Example 49 188 87.5 Example 50 185 87.4 Example 51 181 87.3 Example 52 187 87.5 Example 53 183 87.4

[0191] A comparison of the data from Example 1 and Comparative Example 1 shows that adding organic base additives to the electrolyte can effectively improve the cycle performance of the battery.

[0192] A comparison of the data from Examples 7, 47 to 54 and Comparative Example 4 shows that when the positive electrode active material has a fast ion conductor coating layer, not only can the cycle performance be further improved, but the initial discharge specific capacity and initial efficiency of the battery are also improved.

[0193] 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 secondary battery, comprising a positive electrode and a non-aqueous electrolyte, wherein, The positive active material in the positive electrode sheet has the chemical formula Li ɑ Ni x1 Co y1 Mn z1 M 1-x1-y1-z1 O 2+β , where 0.8 < ɑ < 1.2, 0 < β < 0.1, 0.45 < x1 < 1, 0 < y1 < 0.3, 0 < z1 < 0.5; M is one or more of Ti, Al, Zr, Mg, Y, La, Sr, Zn, Ba, W, Nb, Mo, B The non-aqueous electrolyte includes an organic solvent and an organic base additive, wherein the organic base additive includes any one or more of 5-12-membered aromatic heterocyclic organic bases or 5-12-membered aliphatic heterocyclic organic bases, and the ring structure of the 5-12-membered aromatic heterocyclic organic bases and 5-12-membered aliphatic heterocyclic organic bases contains nitrogen atoms.

2. The secondary battery according to claim 1, wherein, The 5-12-membered aromatic heterocyclic organic bases include compound 1 represented by general formula (I), compound 2 represented by general formula (II), or compound 3 represented by general formula (III); the 5-12-membered alicyclic organic bases include any one or more of compound 4 represented by general formula (IV) or 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 secondary battery 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 secondary battery according to claim 3, 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 secondary battery 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 secondary battery according to claim 2, wherein, The general formula (II) has any one or more of the following characteristics: 1) 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 secondary battery according to claim 6, wherein, In the general formula (II), 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 secondary battery according to claim 7, wherein, In the general formula (II), 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 secondary battery 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 secondary battery according to claim 2, wherein, The general formula (III) has any one or more of the following characteristics: 1)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 secondary battery according to claim 10, wherein, In the general formula (III), 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 secondary battery according to claim 11, wherein, In the general formula (III), 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 secondary battery 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 secondary battery according to claim 2, wherein, The general formula (IV) has any one or more of the following characteristics: 1)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; 3) 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.

15. The secondary battery according to claim 14, wherein, In the general formula (IV), each R 41 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, hydroxyl, -NH2, -N(CH3)2.

16. The secondary battery 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:

17. The secondary battery according to claim 2, wherein, The general formula (V) has any one or more of the following characteristics: 1) 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.

18. The secondary battery according to claim 17, wherein, In the general formula (V), 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.

19. The secondary battery according to claim 18, wherein, In the general formula (V), each R 51 Each is independently selected from any one of hydrogen atom, F atom, methyl, ethyl, n-propyl, and isopropyl.

20. The secondary battery according to claim 2, wherein, In the general formula (V), the compound having the structure shown in general formula (V) is selected from any one or more of the following compounds:

21. The secondary battery according to any one of claims 1 to 20, wherein, The organic base additive has a mass percentage (W1) in the non-aqueous electrolyte, wherein 0.01% ≤ W1 ≤ 20%.

22. The secondary battery according to any one of claims 1 to 20, wherein, 0.05% ≤ W1 ≤ 10%, or 0.5% ≤ W1 ≤ 5%.

23. The secondary battery according to any one of claims 1 to 22, wherein, The surface of the positive electrode active material has a fast ion conductor coating layer.

24. The secondary battery according to claim 23, wherein, The fast ion conductor coating layer has one or more of the following characteristics: 1) The fast ion conductor in the fast ion conductor coating layer has the chemical formula Li 3x2 La 2 / 3-x2 M' a1 TiN z1 O3, Li 2+ 2x3 Zn 1-x3 XO4 or Li 1+x4 M”2(PO4)3, where M' is Ba 2+ and / or Sr 2+ N is Al 3+ and / or Zr 4+ , 0.04≤x2≤0.167, 0≤a1≤1, 0≤z1≤1; X is Al, S, Si, Ge, Ti and P, -0.3<x3<0.8; M” is one or more of Al, Zr, Ti, Ge, Hf and Ti, 0≤x4≤0.5; 2) The fast ion conductor coating layer accounts for 0.1%-0.5% of the total mass of the cathode material; 3) The ion diffusion coefficient of the cathode material having the fast ion conductor coating layer is 10. -9 -10 -6 cm 2 / s.

25. The secondary battery according to claim 24, wherein, The chemical formula of the fast ion conductor is Li. 3x2 La 2 / 3- x2 TiO3, Li 2+2x3 Zn 1-x3 GeO4, Li 1+x4 Al x4 Ti 2-x4 (PO3)4 or Li 1+x4 Al x4 Ge 2-x4 (PO3)4, 0.04≤x2≤0.115, 0<x3<0.5, 0.3≤x4≤0.

5.

26. The secondary battery according to any one of claims 1 to 25, wherein, The compaction density of the positive electrode film layer in the positive electrode sheet is 2.5 / cm². 3 -3.7g / cm 3 Prioritize controlling it at 2.8 / cm. 3 -3.6 / cm 3 .

27. An electrical device comprising a secondary battery, wherein, The secondary battery includes any one of claims 1 to 26.

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