Electrode plate and preparation method thereof, battery and power utilization device

Abstract

The invention relates to an electrode plate and a preparation method thereof, a battery and a power utilization device, the electrode plate comprises a current collector and an electrode film layer arranged on the surface of the current collector, the component of the electrode film layer comprises a silicon compound, and the silicon compound has a group represented by a formula (A); wherein each R1 is independently selected from any one of hydrogen, substituted or unsubstituted alkyl, alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and unsaturated alkyl, and each R1 is not hydrogen at the same time; '*' represents a site where the group shown in the formula (A) is connected with other structures in the silicon compound; # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to an electrode sheet and a preparation method thereof, a battery, and an electrical device. Background Art

[0002] Secondary batteries such as lithium batteries are increasingly widely used due to their clean and renewable characteristics. As the supply of lithium resources becomes increasingly tight, batteries such as sodium batteries and potassium batteries, which have more abundant raw material reserves and lower costs, have come into people's attention.

[0003] However, with the rapid development of the new energy industry, people have an increasing demand for new energy vehicles such as electric cars and electric bicycles, and their performance requirements are also getting higher and higher. Batteries are an important power source for electric cars. Therefore, people have higher and higher performance requirements for batteries. Traditional batteries are increasingly difficult to meet people's needs and need further improvement. Summary of the invention

[0004] Based on this, it is necessary to provide an electrode sheet and a preparation method thereof, a battery, and an electrical device, aiming to improve the coulombic efficiency and cycle performance of the battery.

[0005] The present application is implemented through the following technical solutions.

[0006] In a first aspect of the present application, an electrode sheet is provided, the electrode sheet comprising a current collector and an electrode film layer disposed on the surface of the current collector, the component of the electrode film layer comprising a silicon compound, the silicon compound having a group represented by formula (A):

[0007]

[0008] wherein each R1 is independently selected from any one of hydrogen, substituted or unsubstituted alkyl, alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and unsaturated hydrocarbon, and each R1 is not hydrogen at the same time;

[0009] “*” represents the site where the group represented by formula (A) is connected to other structures in the silicon compound.

[0010] In the above-mentioned electrode sheet, the silicon compound in the electrode film layer contains a specific group represented by formula (A). On the one hand, the silicon compound can capture moisture in the electrode film layer. When the battery is prepared, it can also capture moisture in the electrolyte, thereby reducing the moisture in the battery system and reducing the side reactions of the battery system caused by moisture. On the other hand, when the battery is prepared, the silicon compound in the electrode sheet can also react with the corrosive by-product HF produced in the electrolyte, thereby capturing corrosive by-products such as HF. The two major aspects work together to improve the stability of the battery, thereby improving the coulombic efficiency and cycle performance of the battery.

[0011] In some embodiments, each R1 is independently selected from any one of hydrogen, substituted or unsubstituted alkyl having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 30 carbon atoms, substituted or unsubstituted aryl having 6 to 50 ring atoms, substituted or unsubstituted heteroaryl having 5 to 50 ring atoms, alkenyl having 2 to 30 carbon atoms, and alkynyl having 2 to 30 carbon atoms;

[0012] Optionally, each R1 is independently selected from any one of hydrogen, an unsubstituted alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted by halogen, an unsubstituted cycloalkyl group having 3 to 15 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms substituted by halogen, an alkoxy group having 1 to 15 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 ring atoms, an alkenyl group having 2 to 15 carbon atoms, and an alkynyl group having 2 to 15 carbon atoms.

[0013] In some embodiments, the silicon compound further contains a D group, and the D group is selected from at least one of a borate group, a phosphate group, a phosphinate group, a sulfonate group and an amine group;

[0014] Optionally, the D group is selected from at least one of a borate group, a phosphate group, and a phosphinate group, and the D group and the group represented by formula (A) are connected via an oxygen atom;

[0015] The study found that when the silicon compound also contains a borate structure, when used in the preparation of batteries, the silicon compound can also participate in the formation process of the SEI (or CEI) film, which can further promote the improvement of the membrane structure and improve its toughness, thereby further improving the battery's cycle performance.

[0016] Further research found that when the silicon compound in the electrode also contains phosphate or hypophosphite structures, during the recycling process, it can reduce the dissolution of transition metals in the active material of the electrode, improve the composition stability of the electrode, and further improve the efficiency and cycle performance of the battery.

[0017] Research shows that the reason for the above phenomenon may be that the phosphate or phosphinate groups on the surface of the electrode can react with the oxidizing substances generated during the battery charging and discharging process, reducing the parasitic oxidation current, inhibiting the decomposition of the electrode material by the oxidizing substances, and enhancing the composition stability of the electrode during the charging and discharging process. In traditional technology, when the above silicon compounds are added to the electrolyte, the probability of contact with the oxidizing substances generated during the charging and discharging process is extremely small, so it is basically unable to effectively inhibit metal dissolution and can only play a simple role in removing water.

[0018] Optionally, the D group is an amine group, and the D group and the group represented by formula (A) are connected via a nitrogen atom.

[0019] In some embodiments, the silicon compound comprises at least one of formula (1) to formula (5):

[0020]

[0021] wherein G is selected from boron or phosphorus, each L1 is independently selected from a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT1, and at least one L1 is -OT1, T1 is selected from any one of hydrogen, a group represented by formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T1 is a group represented by formula (A);

[0022] Each L2 is independently selected from a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT2, and at least one L2 is -OT2, T2 is selected from any one of hydrogen, a group represented by formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T2 is a group represented by formula (A);

[0023] Y is selected from a single bond or oxygen, L3 is independently selected from a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT3, and at least one L3 is -OT3, T3 is selected from any one of hydrogen, a group represented by formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T3 is a group represented by formula (A);

[0024] Each L4 is independently selected from any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, and a group represented by formula (A), and at least one L4 is a group represented by formula (A);

[0025] Each L5 is independently selected from a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by the formula (A) and any one of -OT5, and at least one L5 is -OT4, T4 is selected from any one of hydrogen, a group represented by the formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T4 is a group represented by the formula (A).

[0026] In some embodiments, the silicon compound satisfies any one of the following conditions (1) to (5):

[0027] (1) at least two L1 are selected from -OT1;

[0028] Optionally, T1 is selected from any one of hydrogen, a group represented by formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms;

[0029] Further optionally, at least two T1 are selected from the group represented by formula (A);

[0030] (2) at least two L2 are selected from -OT2;

[0031] Optionally, T2 is selected from any one of hydrogen, a group represented by formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms;

[0032] Further optionally, at least two T2 are selected from the group represented by formula (A);

[0033] (3) at least two L3 are selected from -OT3;

[0034] Optionally, T3 is selected from any one of hydrogen, a group represented by formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms;

[0035] Further optionally, at least two T3 are selected from the group represented by formula (A);

[0036] (4) Each L4 is independently selected from hydrogen, an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, an unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms substituted by halogen, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 15 carbon atoms, an alkynyl group having 2 to 15 carbon atoms, and any one of the groups represented by formula (A);

[0037] Optionally, at least two L4 are selected from the group represented by formula (A);

[0038] (5) at least two L5 are selected from -OT5;

[0039] Optionally, T4 is selected from any one of hydrogen, a group represented by formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms;

[0040] Further optionally, at least two T4 are selected from the group represented by formula (A).

[0041] In some embodiments, the silicon compound comprises at least one of formula (1) to formula (3);

[0042] Optionally, G is phosphorus.

[0043] In some of the embodiments, the silicon compound includes at least one of tris(trimethylsilyl)borate, tris(trimethylsilyl)phosphate, tris(trimethylsilyl)phosphite, bis(trimethylsilyl)difluorophosphate, tetra(trimethylsilyl)pyrophosphate, bis(trimethylsilyl)pyromonofluorophosphate, bis(trimethylsilyl)fluorophosphite, tri(methylsilyl)difluorophosphate, hexamethyldisilazane, bistrimethylsilylated vinyl phosphate, tris(vinyldimethylsilane)phosphate, tris(phenyldimethylsilane)phosphate, trimethylsilyl methanesulfonate, heptamethyldisilazane and ethylhexamethyldisilazane. In some embodiments, the silicon compound includes at least one of tris(trimethylsilyl)phosphite, tris(trimethylsilyl)phosphate, bis(trimethylsilyl)fluorophosphite, tris(trimethylsilyl)borate, hexamethyldisilazane, bis(trimethylsilyl)difluorophosphate, tetra(trimethylsilyl)pyrophosphate, bis(trimethylsilyl)vinyl phosphate, tris(vinyldimethylsilane)phosphate, tris(phenyldimethylsilane)phosphate and trimethylsilyl methanesulfonate;

[0044] Optionally, the silicon compound includes at least one of tris(trimethylsilyl)phosphite, tris(trimethylsilyl)phosphate, bis(trimethylsilyl)fluorophosphite, bis(trimethylsilyl)difluorophosphate, tetra(trimethylsilyl)pyrophosphate, bis(trimethylsilyl)vinyl phosphate, tris(vinyldimethylsilane)phosphate and tris(phenyldimethylsilane)phosphate.

[0045] Optionally, the silicon compound includes at least one of tris(trimethylsilyl)phosphite, tris(trimethylsilyl)phosphate, bis(trimethylsilyl)fluorophosphite, bis(trimethylsilyl)difluorophosphate, tetra(trimethylsilyl)pyrophosphate, bis(trimethylsilyl)vinyl phosphate, tris(vinyldimethylsilane)phosphate and tris(phenyldimethylsilane)phosphate.

[0046] When the silicon compound in the electrode sheet also contains a phosphate or hypophosphite structure, during the cycle use process, it can reduce the dissolution of transition metals in the active material of the electrode sheet, improve the composition stability of the electrode sheet, and further improve the efficiency and cycle performance of the battery.

[0047] In some embodiments, in the electrode film layer, the mass percentage of the silicon compound is 0.1% to 1.2%;

[0048] Optionally, the mass percentage of the silicon compound is 0.2% to 1%.

[0049] By regulating the mass proportion of silicon compounds in the electrode film layer, the adverse effects of silicon compounds on other components in the electrode film layer can be minimized while improving the electrode's ability to remove water and adsorb by-products.

[0050] In some embodiments, the components of the electrode film layer further include a positive electrode active material, and the positive electrode active material satisfies one of the following conditions (6) to (8):

[0051] (6) The positive electrode active material includes any one of a positive electrode active material for a lithium ion battery, a positive electrode active material for a sodium ion battery, and a positive electrode active material for a potassium ion battery.

[0052] (7) The positive electrode active material contains a transition metal element;

[0053] Optionally, the transition metal includes iron;

[0054] (8) In the electrode film layer, the mass proportion of the positive electrode active material is 70% to 99.8%.

[0055] In some embodiments, the positive electrode active material is a positive electrode active material of a sodium ion battery.

[0056] As the supply of lithium resources becomes increasingly tight, sodium-ion batteries, which have richer raw material reserves and lower costs for positive electrode active materials of sodium-ion batteries, have come into people's attention. However, compared with positive electrode active materials of lithium-ion batteries, positive electrode active materials of traditional sodium-ion batteries have stronger water absorption and are more likely to absorb moisture, which seriously hinders the improvement of the performance of sodium-ion batteries. The technical solution of the present application can improve the stability of sodium-ion batteries, thereby improving the coulombic efficiency and cycle performance of sodium-ion batteries.

[0057] In some embodiments, the positive electrode active material includes NaFePO4, Na3V2(PO4)3, Na4Fe3(PO4)2(P2O7), NaM1PO4F, Na a M2 b M3 c (CN)6 and Na3(VO y )2(PO4)2F (3-2y) At least one of;

[0058] Among them, M2 and M3 are each independently selected from at least one of Ni, Cu, Fe, Mn, Co and Zn, 0<a≤2, 0<b<1, 0<c<1; M1 is selected from at least one of V, Fe, Mn and Ni, 0≤y≤1.

[0059] In some embodiments, the components of the electrode film layer also include a conductive agent and a binder;

[0060] Optionally, in the electrode film layer, the mass proportion of the conductive agent is 1% to 20%;

[0061] Optionally, in the electrode film layer, the mass proportion of the binder is 1% to 10%.

[0062] In some embodiments, the water content of the electrode film layer is ≤400ppm;

[0063] Optionally, the water content of the electrode film layer is ≤350ppm.

[0064] In a second aspect of the present application, a method for preparing the electrode sheet of the first aspect is provided, comprising the following steps:

[0065] Coating the film slurry on the surface of the current collector to form an electrode film layer to prepare an electrode sheet;

[0066] The components of the membrane layer slurry include the silicon compound.

[0067] According to a third aspect of the present application, a battery is provided, wherein the battery comprises the electrode sheet according to the first aspect or the electrode sheet prepared by the method for preparing the electrode sheet according to the second aspect.

[0068] The battery has high coulombic efficiency and good cycle performance.

[0069] According to a fourth aspect of the present application, there is provided an electrical device, wherein the electrical device comprises the battery according to the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0071] Figure 1 is a schematic diagram of one embodiment of a battery;

[0072] Figure 2 yes Figure 1 Exploded diagram of

[0073] Figure 3 is a schematic diagram of an embodiment of a battery pack;

[0074] Figure 4 yes Figure 3 Exploded diagram of

[0075] Figure 5 is a schematic diagram of an embodiment of an electrical device in which a battery is used as a power source.

[0076] Description of reference numerals:

[0077] 1. Battery pack; 2. Upper box; 3. Lower box; 4. Battery; 41. Shell; 42. Electrode assembly; 43. Cover plate; 5. Electrical device. DETAILED DESCRIPTION

[0078] The following embodiments of the technical solution of the present application will be described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0079] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0080] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0081] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0082] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0083] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0084] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0085] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0086] In the present application, the term "alkyl" refers to a group formed when an alkane loses a hydrogen, such as methane loses a hydrogen to form a methyl group; "alkenyl or alkynyl" refers to a group formed when an alkene or alkyne loses a hydrogen, such as ethylene loses a hydrogen to form vinyl, and acetylene loses a hydrogen to form ethynyl.

[0087] The term "chain alkane" refers to an alkane in which the carbon atoms are connected by single carbon-carbon bonds and do not form a ring, and the remaining valence bonds are all bonded to hydrogen, including straight-chain alkanes and branched-chain alkanes.

[0088] In the present application, the carbon number of the "alkyl group having 1 to 30 carbon atoms" can be 1 to 30, including 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, and non-limiting examples include methane, ethyl, n-propyl, isopropyl, n-butyl, isopropyl Butyl, 2-ethylbutanyl, 3,3-dimethylbutanyl, n-pentanyl, isopentyl, neopentanyl, 1-methylpentanyl, 3-methylpentanyl, 2-ethylpentanyl, 4-methyl-2-pentanyl, n-hexyl, 1-methylhexanyl, 2-ethylhexanyl, 2-butylhexanyl, n-heptyl, 1-methylheptanyl, 2,2-dimethylheptanyl, 2-ethylheptanyl, n-octyl, n-nonanyl, n-decyl.

[0089] In the present application, the "number of ring atoms" refers to the number of atoms bonded to form a ring. When the ring is substituted by a substituent, the atoms contained in the substituent are not included in the ring atoms. The "number of ring atoms" described below is the same unless otherwise specified. For example, the number of ring atoms of a benzene ring is 6, the number of ring atoms of a naphthalene ring is 10, and the number of ring atoms of a thiophene ring is 5.

[0090] "Aryl" refers to a hydrocarbon group containing at least one aromatic ring, including non-condensed aromatic groups and condensed aromatic groups. Condensed aromatic groups refer to groups formed by two or more aromatic rings connected by two common adjacent ring atoms, i.e., condensed rings. Non-limiting examples of aromatic groups include, but are not limited to, phenyl, naphthyl, anthracenyl, phenanthrenyl, biphenyl, terphenyl, benzo[9,10]phenanthrenyl, pyrenyl, benzofluoranthenyl, cycloalkyl (such as fluorenyl, dihydroanthracene), etc.

[0091] In the present application, "heteroaryl" refers to a compound having a closed-loop conjugated system and containing heteroatoms. The heteroatom may be at least one of boron, oxygen, nitrogen, phosphorus, silicon and sulfur, and the number of heteroatoms in the heteroaryl may be 1, 2, 3, 4, 5 or more. The heteroaryl may be a monocyclic heteroaryl or a condensed heteroaryl. It should be understood that a condensed aromatic (hetero) group having one or more (2 or more) carbonyl groups connected thereto is also considered a heteroaryl. Specific examples of heteroaryl groups include, but are not limited to, thienyl, furanyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridinyl, triazinyl, acridinyl, pyridazinyl, pyrazinyl, quinolyl, quinazolinyl, quinoxalinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolyl, indolyl, carbazolyl, benzoxazolyl, benzimidazolyl, benzothiazolyl oxazolyl, benzocarbazolyl, benzothiophenyl, dibenzothiophenyl, thienothiphenyl, benzofuranyl, phenanthrolinyl, isoxazolyl, thiadiazolyl, phenothiazinyl, phenoxathiyl, dibenzo-p-dioxinyl, quinazolinone, benzothiadiazolyl, benzotriazolyl, thianthrenyl, phenothiazinyl, phenoxathiyl, thianthrenthrene tetraoxide group, phenothiazine dioxide group, anthraquinone group, phenoxathiol dioxide group, thioxanthene dioxide group and the like.

[0092] In the present application, the term "substituted or unsubstituted" means that the functional group described after the term may or may not have a substituent.

[0093] "Alkoxy" refers to a group having a structure of -OR, where R is an alkyl group, i.e., an alkyl group as defined above is connected to an adjacent group via an oxygen atom. Phrases containing this term, for example, "alkoxy having 1 to 30 carbon atoms" means that the alkyl moiety contains 1 to 30 carbon atoms. Examples of alkoxy include, but are not limited to, methoxy (-O-CH3 or -OMe), ethoxy (-O-CH2CH3 or -OEt) and tert-butoxy (-OC(CH3)3 or -OtBu).

[0094] In the present application, the halogen group includes chlorine, fluorine, bromine, and iodine.

[0095] In this application, when two groups are connected by a connection point, for example When R is selected from a single bond, it means that the two groups do not need to be connected through a specific group, but are directly connected by a single bond, that is,

[0096] In summary, the power and cycle performance of traditional secondary batteries are increasingly unable to meet people's needs. Traditional technologies mainly focus on developing new materials or adjusting the active material loading on the pole piece to improve the efficiency and cycle performance of the battery. However, the development of new materials is a long and arduous process, and no substantial progress has been made so far. Adjusting the active material loading on the pole piece will bring other negative effects, such as excessive loading, the pole piece is prone to cracking, and ultimately the improvement of the cycle performance is limited.

[0097] Based on this, after a lot of creative exploration, the electrode sheet in this application that can improve the efficiency and cycle performance of the battery was obtained.

[0098] In one embodiment of the present application, an electrode sheet is provided, the electrode sheet comprising a current collector and an electrode film layer disposed on the surface of the current collector, the component of the electrode film layer comprising a silicon compound, the silicon compound having a group represented by formula (A):

[0099]

[0100] wherein each R1 is independently selected from any one of hydrogen, substituted or unsubstituted alkyl, alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and unsaturated hydrocarbon, and each R1 is not hydrogen at the same time;

[0101] “*” represents the site where the group represented by formula (A) is connected to other structures in the silicon compound.

[0102] In the above-mentioned electrode sheet, the silicon compound in the electrode film layer contains a specific group represented by formula (A). On the one hand, the silicon compound can capture moisture in the electrode film layer. When the battery is prepared, it can also capture moisture in the electrolyte, thereby reducing the moisture in the battery system and reducing the side reactions of the battery system caused by moisture. On the other hand, when the battery is prepared, the silicon compound in the electrode sheet can also react with the corrosive by-product HF produced in the electrolyte, thereby capturing corrosive by-products such as HF. The two major aspects work together to improve the stability of the battery, thereby improving the coulombic efficiency and cycle performance of the battery.

[0103] It should be noted that the current collector in the electrode sheet has two surfaces opposite to each other in the direction of its own thickness, and the electrode film layer is arranged on any one or both of the two opposite surfaces of the current collector; further, the above-mentioned electrode film layer can be any functional layer arranged on the surface of the current collector, including but not limited to: active layer and other functional layers, for example, it can be an active layer formed by mixing silicon compounds and active substances, or it can be a newly formed functional layer directly coated with silicon compounds.

[0104] In some embodiments, the electrode film layer is an active layer.

[0105] It can be understood that “*” represents the site where the group represented by formula (A) is connected to other structures in the silicon compound, which means that at least one electron in the group represented by formula (A) will form a covalent bond with an electron in other structures in the silicon compound.

[0106] In some embodiments, each R1 is independently selected from any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms.

[0107] It is understood that in the present application, the group selection range of each R1 is the same, but the specific types of groups selected may be the same or different.

[0108] Optionally, each R1 is independently selected from any one of hydrogen, an unsubstituted alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted by halogen, an unsubstituted cycloalkyl group having 3 to 15 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms substituted by halogen, an alkoxy group having 1 to 15 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 ring atoms, an alkenyl group having 2 to 15 carbon atoms, and an alkynyl group having 2 to 15 carbon atoms.

[0109] In some embodiments, each R1 is independently selected from any one of hydrogen, unsubstituted alkyl having 1 to 15 carbon atoms, alkyl having 1 to 15 carbon atoms substituted by halogen, unsubstituted cycloalkyl having 3 to 15 carbon atoms, cycloalkyl having 3 to 15 carbon atoms substituted by halogen, alkoxy having 1 to 15 carbon atoms, unsubstituted aryl having 6 to 20 ring atoms, aryl having 6 to 20 ring atoms substituted by C1 to C5 alkyl or halogen, unsubstituted heteroaryl having 5 to 20 ring atoms, heteroaryl having 5 to 20 ring atoms substituted by C1 to C5 alkyl or halogen, alkenyl having 2 to 15 carbon atoms and alkynyl having 2 to 15 carbon atoms.

[0110] Optionally, the heteroaromatic group contains at least one heteroatom.

[0111] In some embodiments, the heteroatom in the heteroaromatic group includes at least one of boron, oxygen, nitrogen, phosphorus, silicon and sulfur.

[0112] Optionally, the heteroatom includes at least one of B, O and N.

[0113] In some embodiments, each R1 is independently selected from any one of hydrogen, unsubstituted alkyl having 1 to 10 carbon atoms, alkyl having 1 to 10 carbon atoms substituted by halogen, unsubstituted cycloalkyl having 3 to 10 carbon atoms, cycloalkyl having 3 to 10 carbon atoms substituted by halogen, alkoxy having 1 to 10 carbon atoms, unsubstituted aryl having 6 to 10 ring atoms, aryl having 6 to 10 ring atoms substituted by C1 to C5 alkyl or halogen, unsubstituted heteroaryl having 5 to 10 ring atoms, heteroaryl having 5 to 10 ring atoms substituted by C1 to C5 alkyl or halogen, alkenyl having 2 to 10 carbon atoms and alkynyl having 2 to 10 carbon atoms.

[0114] In some embodiments, each R1 is independently selected from any one of hydrogen, a chain alkyl group having 1 to 5 carbon atoms, a chain alkyl group having 1 to 5 carbon atoms substituted by halogen, an unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms substituted by halogen, an alkoxy group having 1 to 5 carbon atoms, an unsubstituted aryl group having 6 to 5 ring atoms, an aryl group having 6 to 10 ring atoms substituted by C1 to C5 alkyl or halogen, an unsubstituted heteroaryl group having 5 to 10 ring atoms, a heteroaryl group having 5 to 10 ring atoms substituted by C1 to C5 alkyl or halogen, an alkenyl group having 2 to 5 carbon atoms, and an alkynyl group having 2 to 5 carbon atoms.

[0115] In some of these embodiments, each R1 is the same.

[0116] In some of these embodiments, the halogen is selected from F.

[0117] In some embodiments, the silicon compound further contains a D group, and the D group is selected from at least one of a borate group, a phosphate group, a phosphinate group, a sulfonate group, and an amine group.

[0118] It can be understood that the D group and the group represented by formula (A) are connected via the oxygen atom on the D group, thereby forming a silanol group.

[0119] Optionally, the D group is selected from at least one of a borate group, a phosphate group, and a phosphinate group, and the D group and the group represented by formula (A) are connected via an oxygen atom.

[0120] The study found that when silicon compounds contain borate structures, when used in the preparation of batteries, the silicon compounds can also participate in the formation process of the SEI (or CEI) film, which can further promote the improvement of the membrane structure and improve its toughness, thereby further improving the battery's cycle performance.

[0121] Further research found that when the silicon compound in the electrode also contains phosphate or hypophosphite structures, during the recycling process, it can reduce the dissolution of transition metals in the active material of the electrode, improve the composition stability of the electrode, and further improve the efficiency and cycle performance of the battery.

[0122] Studies have shown that the reason for the above phenomenon may be that the phosphate or phosphinate groups on the surface of the electrode can react with the oxidizing substances generated during the battery charging and discharging process, reducing the parasitic oxidation current, inhibiting the decomposition of the electrode material by the oxidizing substances, and enhancing the composition stability of the electrode during the charging and discharging process.

[0123] In some embodiments, the silicon compound comprises at least one of formula (1) to formula (5):

[0124]

[0125] G is selected from boron or phosphorus, each L1 is independently selected from a halogen atom, a substituted or unsubstituted chain alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT1, and at least one L1 is -OT1, T1 is selected from any one of hydrogen, a group represented by formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T1 is a group represented by formula (A).

[0126] It can be understood that the silicon compound represented by formula (1) contains at least one group represented by formula (A).

[0127] In some embodiments, each L1 is independently selected from a halogen atom, a chain alkyl group having 1 to 15 carbon atoms, a chain alkyl group having 1 to 15 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 30 ring atoms, a heteroaryl group having 5 to 25 ring atoms, an alkenyl group having 2 to 15 carbon atoms, an alkynyl group having 2 to 15 carbon atoms, a group represented by formula (A) and -OT1.

[0128] In some embodiments, each L1 is independently selected from a halogen atom, a chain alkyl group having 1 to 10 carbon atoms, a chain alkyl group having 1 to 10 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 15 ring atoms, a heteroaryl group having 5 to 15 ring atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a group represented by formula (A) and -OT1.

[0129] In some embodiments, each L1 is independently selected from a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 10 ring atoms, a heteroaryl group having 5 to 10 ring atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, a group represented by formula (A) and -OT1.

[0130] In some of these embodiments, each L1 is the same or different.

[0131] Furthermore, each T1 is the same or different.

[0132] In some embodiments, each L1 is the same

[0133] In some of these embodiments, at least two L1 are selected from -OT1.

[0134] In some of these embodiments, each L1 is -OT1.

[0135] Optionally, T1 is selected from any one of hydrogen, a group represented by formula (A), a chain alkyl group having 1 to 30 carbon atoms, a chain alkyl group having 1 to 30 carbon atoms substituted by halogen, an aryl group having 6 to 30 ring atoms, a heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms.

[0136] In some embodiments, T1 is selected from any one of hydrogen, a group represented by formula (A), an alkyl group with 1 to 15 carbon atoms, an alkyl group with 1 to 15 carbon atoms substituted by halogen, an aryl group with 6 to 15 ring atoms, a heteroaryl group with 5 to 15 ring atoms, an alkenyl group with 2 to 15 carbon atoms and an alkynyl group with 2 to 15 carbon atoms, and at least one T1 is a group represented by formula (A).

[0137] In some embodiments, T1 is selected from any one of hydrogen, a group represented by formula (A), an alkyl group with 1 to 10 carbon atoms, an alkyl group with 1 to 10 carbon atoms substituted by halogen, an aryl group with 6 to 10 ring atoms, a heteroaryl group with 5 to 10 ring atoms, an alkenyl group with 2 to 10 carbon atoms and an alkynyl group with 2 to 10 carbon atoms, and at least one T1 is a group represented by formula (A).

[0138] In some embodiments, T1 is selected from any one of hydrogen, a group represented by formula (A), an alkyl group with 1 to 5 carbon atoms, an alkyl group with 1 to 5 carbon atoms substituted by halogen, an aryl group with 6 to 10 ring atoms, a heteroaryl group with 5 to 10 ring atoms, an alkenyl group with 2 to 5 carbon atoms and an alkynyl group with 2 to 5 carbon atoms, and at least one T1 is a group represented by formula (A).

[0139] In some embodiments, at least two T1 are selected from the group represented by formula (A).

[0140] In some embodiments, each T1 is selected from the group represented by formula (A).

[0141] Each L2 is independently selected from a halogen atom, a substituted or unsubstituted chain alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT2, and at least one L2 is selected from -OT2, T2 is selected from any one of hydrogen, a group represented by formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T2 is selected from a group represented by formula (A).

[0142] In other words, formula (2) contains at least one group represented by formula (A).

[0143] In some of the embodiments, each L2 is independently selected from a halogen atom, a chain alkyl group having 1 to 30 carbon atoms, a chain alkyl group having 1 to 30 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 50 ring atoms, a heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT2.

[0144] In some of the embodiments, each L2 is independently selected from a halogen atom, a chain alkyl group with 1 to 15 carbon atoms, a chain alkyl group with 1 to 15 carbon atoms substituted by halogen, a cycloalkyl group with 3 to 15 carbon atoms, an aryl group with 6 to 25 ring atoms, a heteroaryl group with 5 to 25 ring atoms, an alkenyl group with 2 to 15 carbon atoms, an alkynyl group with 2 to 15 carbon atoms, a group represented by formula (A) and any one of -OT2.

[0145] In some embodiments, each L2 is independently selected from a halogen atom, a chain alkyl group having 1 to 10 carbon atoms, a chain alkyl group having 1 to 10 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 15 ring atoms, a heteroaryl group having 5 to 15 ring atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a group represented by formula (A) and any one of -OT2.

[0146] In some of the embodiments, each L2 is independently selected from a halogen atom, a chain alkyl group having 1 to 5 carbon atoms, a chain alkyl group having 1 to 5 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 10 ring atoms, a heteroaryl group having 5 to 10 ring atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, a group represented by formula (A) and any one of -OT2.

[0147] In some of these embodiments, each L2 is the same or different.

[0148] In some of these embodiments, each L2 is the same.

[0149] In some of these embodiments, at least two L2 are selected from -OT2.

[0150] In some of these embodiments, each L2 is selected from -OT2.

[0151] In some embodiments, T2 is selected from any one of hydrogen, a group represented by formula (A), a chain alkyl group having 1 to 30 carbon atoms, a chain alkyl group having 1 to 30 carbon atoms substituted by halogen, an aryl group having 6 to 30 ring atoms, a heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms.

[0152] In some embodiments, T2 is selected from any one of hydrogen, a group represented by formula (A), an alkyl group with 1 to 15 carbon atoms, an alkyl group with 1 to 15 carbon atoms substituted by halogen, an aryl group with 6 to 15 ring atoms, a heteroaryl group with 5 to 15 ring atoms, an alkenyl group with 2 to 15 carbon atoms and an alkynyl group with 2 to 15 carbon atoms, and at least one T2 is a group represented by formula (A).

[0153] In some embodiments, T2 is selected from any one of hydrogen, a group represented by formula (A), an alkyl group with 1 to 10 carbon atoms, an alkyl group with 1 to 10 carbon atoms substituted by halogen, an aryl group with 6 to 10 ring atoms, a heteroaryl group with 5 to 10 ring atoms, an alkenyl group with 2 to 10 carbon atoms and an alkynyl group with 2 to 10 carbon atoms, and at least one T2 is a group represented by formula (A).

[0154] In some embodiments, T2 is selected from any one of hydrogen, a group shown in formula (A), an alkyl group with 1 to 5 carbon atoms, an alkyl group with 1 to 5 carbon atoms substituted by halogen, an aryl group with 6 to 10 ring atoms, a heteroaryl group with 5 to 10 ring atoms, an alkenyl group with 2 to 5 carbon atoms and an alkynyl group with 2 to 5 carbon atoms, and at least one T2 is selected from the group shown in formula (A).

[0155] Further optionally, at least two T2 are selected from the group represented by formula (A).

[0156] In some embodiments, T2 is selected from the group shown in formula (A).

[0157] Y is selected from a single bond or oxygen, L3 is independently selected from a halogen atom, a substituted or unsubstituted chain alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT3, and at least one L3 is -OT3, T3 is selected from any one of hydrogen, a group represented by formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T3 is a group represented by formula (A).

[0158] In some of the embodiments, L3 is independently selected from a halogen atom, a chain alkyl group having 1 to 30 carbon atoms, a chain alkyl group having 1 to 30 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 50 ring atoms, a heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT3.

[0159] In some of the embodiments, L3 is independently selected from a halogen atom, a chain alkyl group having 1 to 15 carbon atoms, a chain alkyl group having 1 to 15 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 25 ring atoms, a heteroaryl group having 5 to 25 ring atoms, an alkenyl group having 2 to 15 carbon atoms, an alkynyl group having 2 to 15 carbon atoms, a group represented by formula (A) and any one of -OT3.

[0160] In some of the embodiments, L3 is independently selected from a halogen atom, a chain alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms substituted by halogen, an aryl group having 6 to 15 ring atoms, a heteroaryl group having 5 to 15 ring atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a group represented by formula (A) and -OT3.

[0161] In some of the embodiments, L3 is independently selected from a halogen atom, a chain alkyl group having 1 to 5 carbon atoms, a chain alkyl group having 1 to 5 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 10 ring atoms, a heteroaryl group having 5 to 10 ring atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, a group represented by formula (A) and any one of -OT3.

[0162] In some of these embodiments, each L3 is the same or different.

[0163] In some of these embodiments, the two L3s are selected from -OT3.

[0164] Further optionally, at least two T3 are selected from the group represented by formula (A).

[0165] In some embodiments, each T3 is selected from the group represented by formula (A).

[0166] Each L4 is independently selected from any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, and a group represented by formula (A), and at least one L4 is a group represented by formula (A).

[0167] In other words, formula (4) contains at least one group represented by formula (A).

[0168] In some embodiments, each L4 is independently selected from hydrogen, a chain alkyl group having 1 to 30 carbon atoms, a chain alkyl group having 1 to 30 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 50 ring atoms, a heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, and any one of the groups represented by formula (A).

[0169] In some embodiments, each L4 is independently selected from hydrogen, a chain alkyl group having 1 to 15 carbon atoms, a chain alkyl group having 1 to 15 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 25 ring atoms, a heteroaryl group having 5 to 25 ring atoms, an alkenyl group having 2 to 15 carbon atoms, an alkynyl group having 2 to 15 carbon atoms, and any one of the groups represented by formula (A).

[0170] In some embodiments, each L4 is independently selected from hydrogen, a chain alkyl group having 1 to 10 carbon atoms, a chain alkyl group having 1 to 10 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 15 ring atoms, a heteroaryl group having 5 to 15 ring atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, and any one of the groups represented by formula (A).

[0171] In some embodiments, each L4 is independently selected from hydrogen, a chain alkyl group having 1 to 5 carbon atoms, a chain alkyl group having 1 to 5 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 10 ring atoms, a heteroaryl group having 5 to 10 ring atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, and any one of the groups represented by formula (A).

[0172] In some of these embodiments, each L4 is the same or different.

[0173] In some embodiments, at least two L4 are selected from the group represented by formula (A).

[0174] Each L5 is independently selected from a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and -OT5, and at least one L5 is -OT4, T4 is selected from any one of hydrogen, a group represented by formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T4 is a group represented by formula (A).

[0175] In other words, formula (5) contains at least one group represented by formula (A).

[0176] In some of the embodiments, each L5 is independently selected from a halogen atom, an alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 50 ring atoms, a heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and -OT5.

[0177] In some of the embodiments, each L5 is independently selected from a halogen atom, an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted by halogen, an alkyl group having 1 to 15 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 25 ring atoms, a heteroaryl group having 5 to 25 ring atoms, an alkenyl group having 2 to 15 carbon atoms, an alkynyl group having 2 to 15 carbon atoms, a group represented by formula (A) and any one of -OT5.

[0178] In some embodiments, each L5 is independently selected from a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted by halogen, an alkyl group having 1 to 10 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 15 ring atoms, a heteroaryl group having 5 to 15 ring atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a group represented by formula (A) and any one of -OT5.

[0179] In some embodiments, each L5 is independently selected from a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted by halogen, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group having 6 to 10 ring atoms, a heteroaryl group having 5 to 10 ring atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, a group represented by formula (A) and -OT5.

[0180] In some of these embodiments, each L5 is the same or different.

[0181] In some of these embodiments, at least two L5 are selected from -OT5.

[0182] In some of these embodiments, each L5 is selected from -OT5.

[0183] In some embodiments, T4 is selected from any one of hydrogen, a group represented by formula (A), a chain alkyl group having 1 to 30 carbon atoms, a chain alkyl group having 1 to 30 carbon atoms substituted by halogen, an aryl group having 6 to 30 ring atoms, a heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms.

[0184] In some embodiments, T4 is selected from any one of hydrogen, a group represented by formula (A), a chain alkyl group having 1 to 15 carbon atoms, a chain alkyl group having 1 to 15 carbon atoms substituted by halogen, an aryl group having 6 to 15 ring atoms, a heteroaryl group having 5 to 15 ring atoms, an alkenyl group having 2 to 15 carbon atoms, and an alkynyl group having 2 to 15 carbon atoms.

[0185] In some embodiments, T4 is selected from any one of hydrogen, a group represented by formula (A), a chain alkyl group having 1 to 10 carbon atoms, a chain alkyl group having 1 to 10 carbon atoms substituted by halogen, an aryl group having 6 to 10 ring atoms, a heteroaryl group having 5 to 10 ring atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms.

[0186] In some embodiments, T4 is selected from any one of hydrogen, a group represented by formula (A), a chain alkyl group having 1 to 5 carbon atoms, a chain alkyl group having 1 to 5 carbon atoms substituted by halogen, an aryl group having 6 to 10 ring atoms, a heteroaryl group having 5 to 10 ring atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkynyl group having 2 to 5 carbon atoms.

[0187] In some embodiments, at least two T4 are selected from the group represented by formula (A).

[0188] In some embodiments, each T4 is selected from the group represented by formula (A).

[0189] In some embodiments, the silicon compound includes at least one of formula (1) to formula (3).

[0190] Optionally, G is phosphorus.

[0191] In some of the embodiments, the silicon compound includes at least one of tris(trimethylsilyl)borate, tris(trimethylsilyl)phosphate, tris(trimethylsilyl)phosphite, bis(trimethylsilyl)difluorophosphate, tetra(trimethylsilyl)pyrophosphate, bis(trimethylsilyl)pyromonofluorophosphate, bis(trimethylsilyl)fluorophosphite, tri(methylsilyl)difluorophosphate, hexamethyldisilazane, bistrimethylsilylated vinyl phosphate, tris(vinyldimethylsilane)phosphate, tris(phenyldimethylsilane)phosphate, trimethylsilyl methanesulfonate, heptamethyldisilazane and ethylhexamethyldisilazane.

[0192] In some embodiments, the silicon compound includes at least one of tris(trimethylsilyl)phosphite, tris(trimethylsilyl)phosphate, bis(trimethylsilyl)fluorophosphite, tris(trimethylsilyl)borate, hexamethyldisilazane, bis(trimethylsilyl)difluorophosphate, tetra(trimethylsilyl)pyrophosphate, bis(trimethylsilyl)vinyl phosphate, tris(vinyldimethylsilane)phosphate, tris(phenyldimethylsilane)phosphate and trimethylsilyl methanesulfonate;

[0193] Optionally, the silicon compound includes at least one of tris(trimethylsilyl)phosphite, tris(trimethylsilyl)phosphate, bis(trimethylsilyl)fluorophosphite, bis(trimethylsilyl)difluorophosphate, tetra(trimethylsilyl)pyrophosphate, bis(trimethylsilyl)vinyl phosphate, tris(vinyldimethylsilane)phosphate and tris(phenyldimethylsilane)phosphate.

[0194] In some of the embodiments, in the electrode film layer, the mass percentage of the silicon compound is 0.1% to 1.2%.

[0195] Optionally, the mass percentage of the silicon compound is 0.2% to 1%.

[0196] By regulating the mass proportion of silicon compounds in the electrode film layer, the adverse effects of silicon compounds on other components in the electrode film layer can be minimized while improving the electrode's ability to remove water and adsorb by-products.

[0197] In the above-mentioned "0.1% to 1.2%", the values ​​include the minimum and maximum values ​​of the range, and every value between such minimum and maximum values. Specific examples include but are not limited to the point values ​​in the embodiments and the following point values: 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%; or a range consisting of any two values, for example: 0.1% to 0.2%, 0.1% to 0.3%, 0.1% to 0.4%, 0.1% to 0.5%, 0.1% to 0.6%, 0.1% to 0.7%, 0.1% to 0.8%, 0.1% to 0.9%, 0.2% to 0.3%, 0.2% to 0.4%, 0.2% to 0.5%, 0.2% to 0.6%, 0.1% to 0.7%, 0.1% to 0.8%, 0.1% to 0.9%, 0.2% to 0.3%, 0.2% to 0.4%, 0.2% to 0.5%, 0.2% to 0 .6%, 0.2% to 0.7%, 0.2% to 0.8%, 0.2% to 0.9%, 0.2% to 1%, 0.3% to 0.4%, 0.3% to 0.5%, 0.3% to 0.6%, 0.3% to 0.7%, 0.3% to 0.8%, 0.3% to 0.9%, 0.3% to 1%, 0.4% to 0.5%, 0.4% to 0. 6%, 0.4%~0.7%, 0.4%~0.8%, 0.4%~0.9%, 0.4%~1%, 0.5%~0.6%, 0.5%~0.7%, 0.5%~0.8%, 0.5%~0.9%, 0.5%~1%, 0.6%~0.7%, 0.6%~0.8%, 0.6%~0.9%, 0.6%~1%.

[0198] In some embodiments, the components of the electrode film layer also include positive electrode active materials.

[0199] The positive electrode active material may be a commonly used positive electrode active material in the present application, such as a lithium ion positive electrode active material or a sodium ion positive electrode active material.

[0200] In some of the embodiments, the positive electrode active material includes any one of a positive electrode active material of a lithium ion battery, a positive electrode active material of a sodium ion battery, and a positive electrode active material of a potassium ion battery.

[0201] In some embodiments, the positive electrode active material is a positive electrode active material of a sodium ion battery.

[0202] As the supply of lithium resources becomes increasingly tight, secondary batteries with richer reserves of positive electrode materials and lower costs of sodium ion batteries have come into people's sight. However, compared with the positive electrode active materials of lithium ion batteries, the positive electrode active materials of traditional sodium ion batteries have stronger water absorption and are more likely to absorb moisture, which seriously hinders the improvement of the performance of sodium ion batteries. The technical solution of the present application can improve the stability of sodium ion batteries, thereby improving the coulombic efficiency and cycle performance of sodium ion batteries.

[0203] In some embodiments, the positive electrode active material contains a transition metal element.

[0204] The transition metal includes at least one of chromium, manganese, iron, cobalt, nickel, copper, zinc, palladium, silver, platinum and gold.

[0205] Optionally, the transition metal includes iron.

[0206] The positive electrode active material of a lithium ion battery, the positive electrode active material of a sodium ion battery and the positive electrode active material of a potassium ion battery are hereinafter referred to as lithium ion active material, sodium ion active material and potassium ion active material, respectively.

[0207] Further, as an example, the lithium ion active material may include at least one of the following materials: lithium phosphates containing olivine structure, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (referred to as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds. Examples of lithium-containing phosphates with olivine structure may include but are not limited to at least one of lithium iron phosphate (such as LiFePO4, referred to as LFP), lithium manganese phosphate (such as LiMnPO4), and lithium manganese iron phosphate. In any embodiment of the present application, the molecular formula of the lithium ion active material is: LiFe x Mn (1-x)PO4, x can be any number from 0 to 1.

[0208] It can be understood that when x is 0, LiFe x Mn (1-x) PO4 is LiMnPO4 lithium manganese phosphate. When x is 1, LiFePO4 is LiFePO4 lithium iron phosphate (LFP).

[0209] It should be noted that the lithium content in the positive electrode material exemplified above refers to its content when it is not in use. During the use of the battery, it will be repeatedly used as a battery, and the Li in the positive electrode active material will change during the charging and discharging process, that is, the molar subscript of Li in the positive electrode active material in the battery product will not always remain at 1, but will change; further, the range of change can be (0 to 1.2).

[0210] For example, LiFe x Mn (1-x) PO4 can be further expressed as Li y Fe x Mn (1-x) PO4, y is 0~1.1.

[0211] For example, for the ternary material Li y (Ni a Co b Mn c ) 1-d M d O 2-x A z , y is 0.2~1.2, a+b+c=1, 0≤d≤1, 0≤x<2; M is one or more of Zr, Sr, B, Ti, Mg, Sn and Al, and A is one or more of S, N, F, Cl, Br and I.

[0212] The battery will be accompanied by Li deintercalation and consumption during the charge and discharge process. The molar content of Li is different when the battery is discharged to different states. The above definition of y includes the molar content of Li under different charge and discharge states of the battery; further, the battery voltage is usually between 2-5V.

[0213] As an example, the sodium ion active material may include at least one of the following materials: at least one of a sodium transition metal oxide, a polyanionic compound, and a Prussian blue compound. However, the present 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.

[0214] As an optional technical solution of the present application, in the sodium transition metal oxide, the transition metal includes at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce. The sodium transition metal oxide is, for example, Nax MO2, wherein M includes at least one or more of Ti, V, Mn, Co, Ni, Fe, Cr and Cu, and 0<x≤1.

[0215] As an optional technical solution of the present application, the polyanionic compound can be a compound having sodium ions, transition metal ions and tetrahedral (YO4) n- A class of compounds with anionic units. Transition metals include at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce; Y includes at least one of P, S and Si; n represents (YO4) n- valence state.

[0216] Polyanionic compounds can also be those with sodium ions, transition metal ions, tetrahedral (YO4) n- A class of compounds containing anion units and halogen anions. The transition metal includes at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce; Y includes at least one of P, S and Si, and n represents (YO4) n- valence state; the halogen may be at least one of F, Cl and Br.

[0217] Polyanionic compounds can also be sodium ions, tetrahedral (YO4) n- Anion unit, polyhedral unit (ZO y ) m+ and an optional halogen anion. Y includes at least one of P, S and Si, and n represents (YO4) n- valence state; Z represents a transition metal, including at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce; m represents (ZO y ) m+ valence state; the halogen may be at least one of F, Cl and Br.

[0218] Polyanionic compounds include NaFePO4, Na3V2(PO4)3 (sodium vanadium phosphate, abbreviated as NVP), Na4Fe3(PO4)2(P2O7)(NFPP), NaM1PO4F and Na3(VO y )2(PO4)2F (3-2y) At least one of .

[0219] M1 is at least one of V, Fe, Mn and Ni, and 0≤y≤1.

[0220] Prussian blue compounds can be sodium ions, transition metal ions and cyanide ions (CN -). The transition metal includes at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce. Prussian blue compounds are, for example, Na a M2 b M3 c (CN)6, wherein M2 and M3 are each independently selected from at least one of Ni, Cu, Fe, Mn, Co and Zn, 0<a≤2, 0<b<1, 0<c<1.

[0221] In any embodiment of the present application, in the electrode film layer, the mass proportion of the positive electrode active material is 70% to 99.8%.

[0222] In any embodiment of the present application, the components of the electrode film layer also include a conductive agent and a binder.

[0223] Taking the above electrode sheet as the positive electrode as an example, the conductive agent can be a conductive agent commonly used in the art, including but not limited to: at least one of graphite, carbon nanotubes, nanofibers, carbon black and graphene. Specifically, it can be selected from SP, KS-6, acetylene black, branched Ketjen black ECP, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes CNTs and graphene and their composite conductive agents.

[0224] The binder of the binder can be at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, hydrogenated nitrile rubber, styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), carboxymethyl chitosan (CMCS) and fluorine-containing acrylate resin.

[0225] Optionally, in the electrode film layer, the mass proportion of the conductive agent is 1% to 20%.

[0226] Optionally, in the electrode film layer, the mass proportion of the binder is 1% to 10%.

[0227] In some embodiments, the water content of the electrode film layer is ≤400 ppm.

[0228] Optionally, the water content of the electrode film layer is ≤350ppm.

[0229] In some embodiments, the thickness of the electrode film layer is 30 μm to 200 μm.

[0230] In any embodiment of the present application, the current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum foil may be used. 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 on a polymer material substrate.

[0231] In some embodiments, the metal material is selected from any one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.

[0232] In some of the embodiments, the polymer material substrate includes at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0233] An embodiment of the present application further provides a method for preparing an electrode sheet, comprising the following step S10.

[0234] Step S10, coating a film slurry on the surface of the current collector to form an electrode film layer and prepare an electrode sheet; the components of the film slurry include the above-mentioned silicon compound.

[0235] The types and proportions of silicon compounds are the same as described above and will not be repeated here.

[0236] In any embodiment of the present application, taking the positive electrode sheet as an example, the positive electrode sheet can be prepared in the following manner: the components for preparing the positive electrode sheet are dispersed in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained. The positive electrode slurry has a solid content of 40wt% to 80wt%, and the viscosity at room temperature is adjusted to 5000mPa·s to 25000mPa·s. The positive electrode slurry is coated on the surface of the positive electrode collector, and after drying, it is cold-pressed by a cold rolling mill to form a positive electrode sheet.

[0237] In some embodiments, the surface density of the positive electrode active material contained in the positive electrode sheet is 0.018 g / cm 2 ~0.05g / cm 2 .

[0238] The surface density of the positive electrode active material = the mass of the positive electrode active material / the area of ​​the positive electrode sheet.

[0239] In one embodiment of the present application, a battery is provided, which includes the electrode sheet mentioned above or the electrode sheet prepared by the method for preparing the electrode sheet mentioned above.

[0240] The above battery has high coulombic efficiency and good cycle performance

[0241] In the above-mentioned battery, at least one of the negative electrode sheet or the positive electrode sheet is selected from the above-mentioned electrode sheet; further, the above-mentioned electrode sheet is a positive electrode sheet, and the battery also includes a negative electrode sheet, a separator and an electrolyte. The negative electrode sheet, the separator and the electrolyte are introduced here in a non-restrictive manner.

[0242] [Negative electrode]

[0243] The negative electrode sheet includes a current collector and a negative electrode active layer loaded on the surface of the current collector.

[0244] The components of the negative electrode active layer include a negative electrode active material.

[0245] The negative electrode active material mentioned above can adopt the commonly used negative electrode active materials in this application.

[0246] In any embodiment of the present application, the above-mentioned negative electrode active material includes at least one of mesophase carbon microbeads, graphite, glassy carbon, carbon nanotubes, carbon-carbon composite materials, carbon fibers, hard carbon, soft carbon, silicon-based materials, tin-based materials, magnesium-based materials, and iron-based materials.

[0247] Optionally, specific examples of the above-mentioned negative electrode active materials include, but are not limited to: at least one of mesophase carbon microbeads, natural graphite, artificial graphite, graphene, glassy carbon, carbon nanotubes, carbon fibers, hard carbon, soft carbon, iron oxide, tin oxide, silicon oxide, magnesium oxide, and silicon-carbon composites.

[0248] In any embodiment of the present application, the battery is a lithium battery, and the mass proportion of the negative electrode active material in the negative electrode active layer is 70% to 100%.

[0249] In any embodiment of the present application, the components of the negative electrode active layer further include a negative electrode conductive agent and a negative electrode binder.

[0250] In any embodiment of the present application, the above-mentioned negative electrode conductive agent can be a conductive material commonly used in the art, including but not limited to: at least one of graphite, carbon nanotubes, nanofibers, carbon black and graphene. Specifically, it can be selected from SP, KS-6, acetylene black, branched Ketjen black ECP, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes CNTs and graphene and their composite conductive agents.

[0251] The weight ratio of the negative electrode conductive agent in the negative electrode active layer is 0 to 20 wt % based on the total weight of the negative electrode active layer.

[0252] The above-mentioned negative electrode binder can be a commonly used binder in the art, and can 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).

[0253] The weight ratio of the negative electrode binder in the negative electrode active layer is 0 to 30 wt % based on the total weight of the negative electrode active layer.

[0254] In any embodiment of the present application, the negative electrode active layer may further include other additives, such as thickeners, such as sodium carboxymethyl cellulose (CMC-Na), etc. Based on the total weight of the negative electrode active layer, the weight ratio of other additives in the negative electrode active layer is 0-15wt%.

[0255] In any embodiment of the present application, the current collector in the negative electrode sheet may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil.

[0256] The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be formed by forming a metal material on a polymer material substrate.

[0257] In some embodiments, the metal material is selected from any one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.

[0258] In some of the embodiments, the polymer material substrate includes at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0259] In any embodiment of the present application, the negative electrode sheet can be prepared in the following manner: the above-mentioned components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained. The solid content of the negative electrode slurry is 30wt% to 70wt%, and the viscosity at room temperature is adjusted to 2000mPa·s to 10000mPa·s; the obtained negative electrode slurry is coated on the negative electrode current collector, and after a drying process, cold pressing such as a roller, a negative electrode sheet is obtained.

[0260] In some embodiments, the surface density of the negative electrode active material contained in the negative electrode sheet is 0.005 g / cm 2 ~0.03g / cm 2 .

[0261] The surface density of the negative electrode active material = the mass of the negative electrode active material / the area of ​​the negative electrode sheet.

[0262] The above electrolyte has excellent wettability to the electrode, especially when the active material loading and thickness on the electrode are high, it can wet the electrode more quickly, improve the interface wettability of the electrode, and thus promote the capacity utilization efficiency of the battery.

[0263] It should be noted that if the battery is a "negative electrode-free sodium battery", no negative electrode active material is added during the preparation of the negative electrode sheet. Only the negative electrode current collector or the current collector coated with a conductive agent is used as the nominal negative electrode. The negative electrode current collector does not have the function of a negative electrode in the actual sense. After the assembled battery is charged for the first time, the sodium element in the positive electrode migrates to the surface of the negative electrode current collector, and a sodium metal layer is formed on the negative electrode current collector, thereby obtaining a true negative electrode.

[0264] [Isolation film]

[0265] The separator is arranged between the positive electrode sheet and the negative electrode sheet.

[0266] The present application has no particular limitation on the type of isolation membrane, and any known porous isolation membrane with good chemical stability and mechanical stability can be selected.

[0267] In some embodiments, the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0268] The thickness of the diaphragm is controlled within a range of 2 μm to 15 μm; optionally, the thickness of the diaphragm is controlled within a range of 2 μm to 13 μm.

[0269] [Electrolyte]

[0270] The electrolyte solution includes an electrolyte salt and a solvent.

[0271] In some embodiments, the electrolyte salt can be selected from electrolyte salts commonly used in the art, such as lithium ion electrolyte salts, sodium ion electrolyte salts and potassium ion electrolyte salts. The specific type can be selected according to the type of the positive electrode active material. For example, if the positive electrode active material is a lithium ion positive electrode active material, the electrolyte salt is a lithium ion electrolyte salt. If the positive electrode active material is a sodium ion positive electrode active material, the electrolyte salt is a sodium ion electrolyte salt.

[0272] As an example, the lithium ion electrolyte salt includes, but is not limited to, one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium dioxalatoborate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorobis(oxalatophosphate) (LiDFOP) and lithium tetrafluorooxalatophosphate (LiTFOP).

[0273] As an example, the sodium ion electrolyte salt includes, but is not limited to, one or more of sodium hexafluorophosphate, sodium difluorooxalatoborate, sodium tetrafluoroborate, sodium bisoxalatoborate, sodium perchlorate, sodium hexafluoroarsenate, sodium bis(fluorosulfonyl)imide, sodium trifluoromethylsulfonate, and sodium bis(trifluoromethylsulfonyl)imide.

[0274] In some embodiments, the solvent may be selected from fluoroethylene carbonate (FEC), ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MPC), methyl methacrylate (MF), methyl methacrylate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MPC), methyl methacrylate (MPC), ethyl methacrylate (EPC), butylene carbonate (BC), methyl formate (MF), methyl acetate ... Ester (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), cyclopentane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, crown ether or more.

[0275] Optionally, the solvent is selected from one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0276] The above-mentioned ether solvent molecules can construct a stable electrode / electrolyte interface on the surface of the sodium metal negative electrode (including no negative electrode, the negative electrode design of this application is no negative electrode), forming a stable solid electrolyte interface (SEI), reducing electrochemical polarization

[0277] In some embodiments, the concentration of the electrolyte salt in the electrolyte is generally 0.5 mol / L

[0278] ~8mol / L; the concentration of electrolyte salt is usually 1mol / L~4mol / L.

[0279] In some embodiments, the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0280] In some embodiments, the battery is a lithium battery, a sodium battery, or a potassium battery.

[0281] Furthermore, the battery is a negative electrode-free sodium battery.

[0282] The present application has no particular limitation on the shape of the battery, which may be cylindrical, square or any other shape. For example, Figure 1 The battery 4 is a square structure as an example.

[0283] In some embodiments, reference Figure 2 The housing may include a shell 41 and a cover plate 43. The shell 41 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 41 has an opening connected to the receiving cavity, and the cover plate 43 can be covered on the opening to close the receiving cavity.

[0284] The positive electrode sheet, the negative electrode sheet and the separator can be wound or laminated to form an electrode assembly 42. The electrode assembly 42 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 42. The number of electrode assemblies 42 included in the battery 4 can be one or more, which can be adjusted according to needs.

[0285] The present application also provides an electrical device, which includes the above-mentioned battery.

[0286] Furthermore, in the above-mentioned electrical device, the battery may exist in the form of a battery cell, or may be further assembled into a battery pack.

[0287] Figure 3 and Figure 4 The battery pack 1 is used as an example. The battery pack 1 includes a battery box and one or more batteries 4 arranged in the battery box. The battery box includes an upper box body 2 and a lower box body 3. The upper box body 2 can be covered on the lower box body 3 and form a closed space for the battery 4.

[0288] The multiple batteries 4 can be arranged in the battery box in any manner.

[0289] The above-mentioned battery or the battery pack assembled therefrom can be used as a power source for an electrical device, and can also be used as an energy storage unit for an electrical device.

[0290] The above-mentioned electrical devices may be, but are not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as 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.

[0291] Figure 5 The power consumption device 5 is taken as an example. The power consumption device 5 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. In order to meet the power consumption device 5's requirements for high power and high energy density of the secondary battery, a battery pack may be used.

[0292] As another example, the power-consuming device may be a mobile phone, a tablet computer, a notebook computer, etc. Such a device is usually required to be light and thin, and a battery may be used as a power source.

[0293] The present invention will be described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. It should be understood that the attached claims summarize the scope of the present invention. Under the guidance of the concept of the present invention, those skilled in the art should realize that certain changes made to the various embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

[0294] The following are specific embodiments.

[0295] Example 1

[0296] S1. Preparation of sodium battery

[0297] (1) Preparation of positive electrode sheet

[0298] The polyvinylidene fluoride binder is fully dissolved in N-methylpyrrolidone, and a silicon compound, a carbon black conductive agent and a positive electrode active material Na4Fe3(PO4)2P2O7 are added to prepare a uniformly dispersed active slurry. The solid content of the active slurry is 50%, and the viscosity at 25°C and normal pressure is 8800mPa·s; wherein the mass ratio of the positive electrode active material, the conductive agent, the polyvinylidene fluoride binder and the silicon compound is 80:10:9.5:0.5.

[0299] The active slurry is evenly coated on the surface of the aluminum foil, and then transferred to a vacuum drying oven for drying: dried at 120°C for 2 hours, the dried electrode is rolled, and then punched to obtain the positive electrode.

[0300] The thickness of the active layer in the positive electrode sheet was tested: specifically, the thickness of the positive electrode sheet and the current collector were measured by a spiral micrometer, and the difference between the two was calculated to obtain the thickness of the active layer, which was 204 μm.

[0301] The components in the active layer of the positive electrode were characterized by infrared spectrometer: the results showed the characteristic peak of trimethylsilyl (TMS group), and the component proportion was quantitatively determined based on the contrast absorption peak intensity of the characteristic peak in the infrared spectrum. The types of silicon compounds and their mass proportion H1 in the active layer are shown in Table 1.

[0302] The water content in the active layer of the positive electrode sheet was measured using a KF type trace moisture tester. The specific steps refer to the standard GB / T 11133-2015, Karl Fischer coulometric titration method. The results are shown in Table 1.

[0303] (2) Preparation of negative electrode sheet

[0304] The binder sodium carboxymethyl cellulose CMC and the conductive agent carbon nanotubes are mixed in a mass ratio of 3:2 and added to water, stirred into a uniform slurry with a solid content of 2%. The slurry is coated on the surface of the copper foil and then transferred to a vacuum drying oven for complete drying. The negative electrode sheet is then punched out to obtain a slurry layer with a thickness of 1.2 μm.

[0305] (3) Preparation of electrolyte

[0306] In an argon atmosphere glove box (H2O<0.1ppm, O2<0.1ppm), sodium hexafluorophosphate sodium salt was dissolved in an organic solvent of ethylene glycol dimethyl ether and stirred evenly to obtain an electrolyte with a sodium hexafluorophosphate sodium salt concentration of 1.0 mol / L.

[0307] (4) Isolation film: Polypropylene film is used as the isolation film.

[0308] (5) Preparation of sodium battery: stack the above-mentioned positive electrode sheet, separator, and negative electrode sheet in order, so that the separator is between the positive and negative current collectors to play an isolating role, and add the above-mentioned electrolyte to assemble into a stacked battery.

[0309] S2. Performance test of sodium battery:

[0310] 1. Coulomb efficiency

[0311] The prepared sodium battery was charged to 3.7V at a constant current of 1 / 3C at 25°C, and then charged at a constant voltage of 3.7V until the current dropped to 0.05C to obtain the first charging capacity (Cc1); then discharged to 2.5V at a constant current of 1 / 3C to obtain the first discharge capacity (Cd1), and the coulombic efficiency of the sodium battery was calculated according to the following formula.

[0312] Coulomb efficiency = first discharge capacity (Cd1) / first charge capacity (Cc1)×100%.

[0313] 2. Cyclic capacity retention rate

[0314] The sodium battery is charged to 3.7V at a constant current of 1C at 45°C, then charged at a constant voltage of 3.7V until the current drops to 0.05C, and then discharged to 2.5V at a constant current of 1C to obtain the first cycle discharge capacity Cd1; this charging and discharging is repeated until the nth cycle, and the discharge capacity of the sodium battery after n cycles is obtained, recorded as Cdn, and the sodium battery capacity retention rate is calculated according to the following formula:

[0315] Capacity retention rate P n = discharge capacity after n cycles (Cdn) / first cycle discharge capacity (Cd1) × 100%. The capacity retention rate after 200 cycles is recorded as P 200 .

[0316] 3. Monitoring of sodium dendrite growth

[0317] Take the sodium battery after 200 cycles in the cycle test of step 2 above, disassemble the sodium battery in an argon atmosphere glove box (H2O <0.1ppm, O2 <0.1ppm), and visually observe the surface morphology of the negative electrode to determine whether sodium dendrites are generated: if there are no white spots on the negative electrode sheet, it is judged that there are no sodium dendrites; if there are sporadic white spots on the negative electrode sheet, it is judged that the sodium dendrites are mild; if there are dense white spots on the negative electrode sheet, it is judged that the sodium dendrites are severe.

[0318] 4. Take the sodium battery after 200 cycles in the cycle test of step 2 above, disassemble the sodium battery in an argon atmosphere glove box (H2O<0.1ppm, O2<0.1ppm), make the negative electrode sheet into small discs, and then perform ICP-MS test and analysis after digestion. The content of transition metal Fe on the negative electrode sheet after 200 cycles can be regarded as the dissolution amount of transition metal Fe in the positive electrode sheet, which is recorded as F0.

[0319] Embodiments 2 to 14

[0320] Examples 2 to 14 are basically the same as Example 1, except that: in step (1), in the preparation of the positive electrode sheet, the type of silicon compound or its mass proportion in the active layer is different from that in Example 1, wherein when adjusting the mass proportion of the silicon compound, the mass proportion of the silicon compound and the binder is adjusted respectively on the premise of maintaining the total mass proportion of the silicon compound and the binder, so that the mass proportion of the silicon compound is different from that in the example, and the mass proportion of other components is the same as that in Example 1. See Table 1 for specific parameters.

[0321] The other step conditions are the same as those in Example 1. The test results are shown in Table 1.

[0322] Comparative Example 1

[0323] Comparative Example 1 is basically the same as Example 1, except that: in step (1), in the preparation of the positive electrode sheet, no silicon compound is added, and the mass ratio of the positive electrode active material, the conductive agent, and the polyvinylidene fluoride binder is 80:10:10. For specific parameters, please see Table 1.

[0324] The other step conditions are the same as those in Example 1. The test results are shown in Table 1.

[0325] Comparative Example 2

[0326] Comparative Example 2 is substantially the same as Comparative Example 1, except that in step (1), the silicon compound is replaced with an equal mass of sodium dodecylbenzene sulfonate. For specific parameters, see Table 1.

[0327] The other step conditions are the same as those in Comparative Example 1. Please see Table 1 for the test results.

[0328] Comparative Example 3

[0329] Comparative Example 3 is basically the same as Example 1, except that: in step (1), in the preparation of the positive electrode sheet, no silicon compound is added, and the mass ratio of the positive electrode active material, the conductive agent, and the polyvinylidene fluoride binder is 80:10:10; at the same time, in the preparation of the electrolyte in step (3), tris(trimethylsilyl) phosphate is added to the electrolyte with a mass ratio of 2%.

[0330] The relevant parameters and performance results of each embodiment and comparative example are shown in Table 1. The mass proportion of the silicon compound in the active layer is H1, and the dissolution amount of transition metal Fe in the positive electrode sheet is F0.

[0331] Table 1

[0332]

[0333]

[0334] Note: In Table 1, “ / ” means that the substance or parameter does not exist.

[0335] Analysis of the data in Table 1: By comparing the results of Example 1 with Comparative Examples 1 to 2, it can be seen that in the electrode sheet of the present application, adding a silicon compound containing a specific group to the electrode film layer can improve the stability of the battery, thereby improving the coulombic efficiency and cycle performance of the battery. Furthermore, when the silicon compound also contains a phosphate group, it can significantly inhibit the dissolution of transition metals such as iron in the electrode sheet, further improving the cycle performance of the battery.

[0336] Furthermore, by comparing the results of Example 1 with those of Comparative Example 3, it can be seen that by adopting the technical solution of the present application and adding silicon compounds containing specific groups to the electrode film layer, the functions of removing water and effectively inhibiting metal dissolution can be simultaneously achieved, while the silicon compounds only play a simple role of removing water in the electrolyte.

[0337] Studies have shown that the reasons for the above phenomenon may be: the phosphate or phosphinate groups on the surface of the electrode can react with the oxidizing substances generated during the charging and discharging process of the battery, reducing the parasitic oxidation current, inhibiting the decomposition of the electrode material by the oxidizing substances, and enhancing the composition stability of the electrode during the charging and discharging process. However, the probability of contact with the oxidizing substances generated during the charging and discharging process in the electrolyte is extremely small, so it is basically impossible to effectively inhibit metal dissolution.

[0338] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0339] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims, and the description and drawings can be used to interpret the content of the claims.

Claims

1. An electrode sheet, characterized in that: The electrode sheet includes a current collector and an electrode film layer disposed on the surface of the current collector. The components of the electrode film layer include a silicon compound. The silicon compound has a group represented by formula (A): wherein each R1 is independently selected from any one of hydrogen, substituted or unsubstituted alkyl, alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and unsaturated hydrocarbon, and each R1 is not hydrogen at the same time; "*" represents the site where the group represented by formula (A) is connected to other structures in the silicon compound.

2. The electrode sheet according to claim 1, characterized in that: Each R1 is independently selected from any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms; Optionally, each R1 is independently selected from any one of hydrogen, an unsubstituted alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted by halogen, an unsubstituted cycloalkyl group having 3 to 15 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms substituted by halogen, an alkoxy group having 1 to 15 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 20 ring atoms, an alkenyl group having 2 to 15 carbon atoms, and an alkynyl group having 2 to 15 carbon atoms.

3. The electrode sheet according to claim 1, characterized in that: The silicon compound further contains a D group, wherein the D group is selected from at least one of a borate group, a phosphate group, a phosphinate group, a sulfonate group and an amine group; Optionally, the D group is selected from at least one of a borate group, a phosphate group, and a phosphinate group, and the D group and the group represented by formula (A) are connected via an oxygen atom; Optionally, the D group is an amine group, and the D group and the group represented by formula (A) are connected via a nitrogen atom.

4. The electrode sheet according to any one of claims 1 to 3, characterized in that: The silicon compound comprises at least one of formula (1) to formula (5): wherein G is selected from boron or phosphorus, each L1 is independently selected from a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT1, and at least one L1 is -OT1, T1 is selected from any one of hydrogen, a group represented by formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T1 is a group represented by formula (A); Each L2 is independently selected from a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT2, and at least one L2 is -OT2, T2 is selected from any one of hydrogen, a group represented by formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T2 is a group represented by formula (A); Y is selected from a single bond or oxygen, L3 is independently selected from a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by formula (A) and any one of -OT3, and at least one L3 is -OT3, T3 is selected from any one of hydrogen, a group represented by formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T3 is a group represented by formula (A); Each L4 is independently selected from any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, and a group represented by formula (A), and at least one L4 is a group represented by formula (A); Each L5 is independently selected from a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 ring atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group represented by the formula (A) and any one of -OT5, and at least one L5 is -OT4, T4 is selected from any one of hydrogen, a group represented by the formula (A), a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group and an unsaturated hydrocarbon group, and at least one T4 is a group represented by the formula (A).

5. The electrode sheet according to claim 4, characterized in that: The silicon compound satisfies any one of the following conditions (1) to (5): (1) at least two L1 are selected from -OT1; Optionally, T1 is selected from any one of hydrogen, a group represented by formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms; Further optionally, at least two T1 are selected from the group represented by formula (A); (2) at least two L2 are selected from -OT2; Optionally, T2 is selected from any one of hydrogen, a group represented by formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms; Further optionally, at least two T2 are selected from the group represented by formula (A); (3) at least two L3 are selected from -OT3; Optionally, T3 is selected from any one of hydrogen, a group represented by formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms; Further optionally, at least two T3 are selected from the group represented by formula (A); (4) Each L4 is independently selected from hydrogen, an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, an unsubstituted cycloalkyl group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms substituted by halogen, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 15 carbon atoms, an alkynyl group having 2 to 15 carbon atoms, and any one of the groups represented by formula (A); Optionally, at least two L4 are selected from the group represented by formula (A); (5) at least two L5 are selected from -OT5; Optionally, T4 is selected from any one of hydrogen, a group represented by formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted by halogen, a substituted or unsubstituted aryl group having 6 to 30 ring atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, an alkenyl group having 2 to 30 carbon atoms, and an alkynyl group having 2 to 30 carbon atoms; Further optionally, at least two T4 are selected from the group represented by formula (A).

6. The electrode sheet according to claim 4, characterized in that: The silicon compound comprises at least one of formula (1) to formula (3); Optionally, G is phosphorus.

7. The electrode sheet according to any one of claims 1 to 3, characterized in that: The silicon compound includes at least one of tris(trimethylsilyl)borate, tris(trimethylsilyl)phosphate, tris(trimethylsilyl)phosphite, di(trimethylsilyl)difluorophosphate, tetra(trimethylsilyl)pyrophosphate, di(trimethylsilyl)pyromonofluorophosphate, di(trimethylsilyl)fluorophosphite, (trimethylsilyl)difluorophosphate, hexamethyldisilazane, bis(trimethylsilyl)vinyl phosphate, tris(vinyldimethylsilane)phosphate, tris(phenyldimethylsilane)phosphate, trimethylsilyl methanesulfonate, heptamethyldisilazane and ethylhexamethyldisilazane.

8. The electrode sheet according to any one of claims 1 to 3, characterized in that: The silicon compound includes at least one of tris(trimethylsilyl)phosphite, tris(trimethylsilyl)phosphate, bis(trimethylsilyl)fluorophosphite, tris(trimethylsilyl)borate, hexamethyldisilazane, bis(trimethylsilyl)difluorophosphate, tetra(trimethylsilyl)pyrophosphate, bis(trimethylsilyl)vinyl phosphate, tris(vinyldimethylsilane)phosphate, tris(phenyldimethylsilane)phosphate and trimethylsilyl methanesulfonate; Optionally, the silicon compound includes at least one of tris(trimethylsilyl)phosphite, tris(trimethylsilyl)phosphate, bis(trimethylsilyl)fluorophosphite, bis(trimethylsilyl)difluorophosphate, tetra(trimethylsilyl)pyrophosphate, bis(trimethylsilyl)vinyl phosphate, tris(vinyldimethylsilane)phosphate and tris(phenyldimethylsilane)phosphate.

9. The electrode sheet according to any one of claims 1 to 3, characterized in that: In the electrode film layer, the mass proportion of the silicon compound is 0.1% to 1.2%; Optionally, the mass percentage of the silicon compound is 0.2% to 1%.

10. The electrode sheet according to any one of claims 1 to 3, characterized in that: The components of the electrode film layer also include a positive electrode active material, and the positive electrode active material satisfies one of the following conditions (6) to (8): (6) The positive electrode active material includes any one of a positive electrode active material for a lithium ion battery, a positive electrode active material for a sodium ion battery, and a positive electrode active material for a potassium ion battery; (7) The positive electrode active material contains a transition metal element; Optionally, the transition metal includes iron; (8) In the electrode film layer, the mass proportion of the positive electrode active material is 70% to 99.8%.

11. The electrode sheet according to claim 10, characterized in that: The positive electrode active material is a positive electrode active material of a sodium ion battery.

12. The electrode sheet according to claim 10, characterized in that: The positive electrode active material includes NaFePO4, Na3V2(PO4)3, Na4Fe3(PO4)2(P2O7), NaM1PO4F, Na a M2 b M3 c (CN)6 and Na3(VO y )2(PO4)2F (3-2y) At least one of; Among them, M2 and M3 are each independently selected from at least one of Ni, Cu, Fe, Mn, Co and Zn, 0<a≤2, 0<b<1, 0<c<1; M1 is selected from at least one of V, Fe, Mn and Ni, 0≤y≤1.

13. The electrode sheet according to any one of claims 1 to 3, characterized in that: The components of the electrode film layer also include a conductive agent and a binder; Optionally, in the electrode film layer, the mass proportion of the conductive agent is 1% to 20%; Optionally, in the electrode film layer, the mass proportion of the binder is 1% to 10%.

14. The electrode sheet according to any one of claims 1 to 3, characterized in that: The water content of the electrode film layer is ≤400ppm; Optionally, the water content of the electrode film layer is ≤350ppm.

15. The method for preparing an electrode sheet according to any one of claims 1 to 14, characterized in that: The steps include: Coating the film slurry on the surface of the current collector to form an electrode film layer to prepare an electrode sheet; The components of the membrane layer slurry include the silicon compound.

16. A battery, characterized in that: The battery comprises the electrode sheet according to any one of claims 1 to 14 or an electrode sheet prepared by the method for preparing the electrode sheet according to claim 15.

17. An electrical device, characterized in that: The electrical device comprises the battery as claimed in claim 16.

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