Electrode sheet, method for manufacturing the same, battery, and electric device

Abstract

The application relates to an electrode sheet, a preparation method thereof, a battery and a power utilization device. The electrode sheet comprises a current collector and an electrode film layer arranged on the surface of the current collector. The components of the electrode film layer comprise a silicon compound. The electrode sheet can improve the coulomb efficiency and cycle performance of the battery.

Description

Electrode sheets and their preparation methods, batteries, and electrical devices Technical Field

[0001] This invention relates to the field of battery technology, and in particular to an electrode sheet and its preparation method, a battery, and an electrical device. Background Technology

[0002] Lithium batteries and other rechargeable batteries are increasingly widely used due to their clean and renewable characteristics. As the supply of lithium resources becomes increasingly tight, batteries with more abundant raw material reserves and lower costs, such as sodium batteries and potassium batteries, are coming into view.

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

[0004] Therefore, it is necessary to provide an electrode sheet and its preparation method, a battery, and an electrical device, with the aim of improving the coulombic efficiency and cycle performance of the battery.

[0005] This application is achieved through the following technical solution.

[0006] A first aspect of this application provides an electrode sheet comprising a current collector and an electrode film layer disposed on the surface of the current collector, wherein the electrode film layer comprises a silicon compound having a group represented by formula (A):

[0007]

[0008] 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 shown in formula (A) is connected to other structures in the silicon compound.

[0010] In the aforementioned electrode sheet, the silicon compound in the electrode film contains a specific group shown in formula (A). On the one hand, the silicon compound can capture moisture in the electrode film and, when fabricated into a battery, can also capture moisture in the electrolyte, thereby reducing the moisture content in the battery system and minimizing side reactions caused by moisture. On the other hand, when fabricated into a battery, the silicon compound in the electrode sheet can also react with the corrosive byproduct HF generated in the electrolyte, thereby capturing corrosive byproducts such as HF. The combined effect of these two aspects can 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 groups having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 30 carbon atoms, substituted or unsubstituted alkoxy groups having 1 to 30 carbon atoms, substituted or unsubstituted aryl groups having 6 to 50 cyclic atoms, substituted or unsubstituted heteroaryl groups having 5 to 50 cyclic atoms, alkenyl groups having 2 to 30 carbon atoms, and alkynyl groups 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, a halogen-substituted alkyl group having 1 to 15 carbon atoms, an unsubstituted cycloalkyl group having 3 to 15 carbon atoms, a halogen-substituted cycloalkyl group having 3 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, an aryl group having 6 to 20 substituted or unsubstituted cyclic atoms, a heteroaryl group having 5 to 20 substituted or unsubstituted cyclic 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, the D group being selected from at least one group selected from borate ester group, phosphate ester group, phosphinate ester group, sulfonate ester group and amine group;

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

[0015] Research has found that when silicon compounds also contain borate ester structures, they can participate in the formation of the SEI (or CEI) film when used in battery manufacturing, further promoting the improvement of the film structure, enhancing its toughness, and thus further improving the cycle performance of the battery.

[0016] Further research revealed that when the silicon compounds in the electrode sheet also contain phosphate esters or hypophosphite structures, the amount of transition metals dissolved in the active material of the electrode sheet can be reduced during cycling, thereby improving the compositional stability of the electrode sheet and further enhancing the efficiency and cycle performance of the battery.

[0017] Studies suggest that the above phenomenon may be due to the fact that phosphate or phosphonate groups on the electrode surface can react with oxidizing substances generated during battery charging and discharging, reducing parasitic oxidation current, inhibiting the decomposition of electrode materials by oxidizing substances, and enhancing the compositional stability of the electrode during charging and discharging. In contrast, in traditional technologies, when the aforementioned silicon compounds are added to the electrolyte, the probability of contact with oxidizing substances generated during charging and discharging is extremely small, thus they are essentially unable to effectively inhibit metal dissolution and can only serve a simple water removal function.

[0018] Optionally, the D group is an amino group, and the D group and the group shown in formula (A) are connected by a nitrogen atom.

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

[0020]

[0021] Wherein, G is selected from boron or phosphorus, each L1 is independently selected from any one of the following: halogen atom, substituted or unsubstituted alkyl group with 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5 to 50 cyclic atoms, alkenyl group with 2 to 30 carbon atoms, alkynyl group with 2 to 30 carbon atoms, group shown in formula (A), and -OT1, and at least one L1 is -OT1, T1 is selected from any one of the following: hydrogen, group shown in formula (A), substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, and unsaturated hydrocarbon group, and at least one T1 is group shown in formula (A).

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

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

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

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

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

[0027] (1) At least two L1s are selected from -OT1;

[0028] Optionally, T1 is selected from any one of hydrogen, the group shown in formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted with halogen, an aryl group having 6 to 30 substituted or unsubstituted ring atoms, a heteroaryl group having 5 to 30 substituted or unsubstituted 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 T1s are selected from the groups shown in formula (A);

[0030] (2) At least two L2s are selected from -OT2;

[0031] Optionally, T2 is selected from any one of hydrogen, the group shown in formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted with halogen, an aryl group having 6 to 30 substituted or unsubstituted ring atoms, a heteroaryl group having 5 to 30 substituted or unsubstituted 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 groups are selected from the groups shown in formula (A);

[0033] (3) At least two L3s are selected from -OT3;

[0034] Optionally, T3 is selected from any one of hydrogen, the group shown in formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted with halogen, an aryl group having 6 to 30 substituted or unsubstituted ring atoms, a heteroaryl group having 5 to 30 substituted or unsubstituted 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 T3s are selected from the groups shown in formula (A);

[0036] (4) Each L4 is independently selected from any one of the following: hydrogen, unsubstituted alkyl group with 1 to 30 carbon atoms, alkyl group with 1 to 30 carbon atoms substituted by halogen, cycloalkyl group with 3 to 30 carbon atoms substituted by halogen, aryl group with 6 to 30 substituted or unsubstituted cyclic group, heteroaryl group with 5 to 30 substituted or unsubstituted cyclic group, alkenyl group with 2 to 15 carbon atoms, alkynyl group with 2 to 15 carbon atoms, and the group shown in formula (A);

[0037] Optionally, at least two L4 groups are selected from the groups shown in formula (A);

[0038] (5) At least two L5s are selected from -OT5;

[0039] Optionally, T4 is selected from any one of hydrogen, the group shown in formula (A), an unsubstituted alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted with halogen, an aryl group having 6 to 30 substituted or unsubstituted ring atoms, a heteroaryl group having 5 to 30 substituted or unsubstituted 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 groups are selected from the groups shown in formula (A).

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

[0042] Optionally, G is phosphorus.

[0043] In some embodiments, the silicon compound includes at least one of tris(trimethylsilyl)borate, tris(trimethylsilyl) phosphate, tris(trimethylsilyl) phosphite, di(trimethylsilyl) difluorobiphosphate, tetra(trimethylsilyl) pyrophosphate, di(trimethylsilyl) pyromonofluorophosphate, di(trimethylsilyl) fluorophosphite, di(trimethylsilyl) difluorophosphate, hexamethyldisilazane, bis(trimethylsilyl)vinyl phosphate, tris(vinyldimethylsilane) phosphate, tris(phenyldimethylsilane) phosphate, trimethylsilylmethanesulfonate, heptamethyldisilazane, and ethylhexamethyldisilazane. In some embodiments, the silicon compound includes at least one selected from the following: tris(trimethylsilyl) phosphite, tris(trimethylsilyl) phosphate, di(trimethylsilyl) fluorophosphite, tris(trimethylsilyl) borate, hexamethyldisilazane, di(trimethylsilyl) difluorobiphosphate, 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, di(trimethylsilyl) fluorophosphite, di(trimethylsilyl) difluorobiphosphate, 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, di(trimethylsilyl) fluorophosphite, di(trimethylsilyl) difluorobiphosphate, 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 phosphate ester or hypophosphite structure, it can reduce the dissolution of transition metals in the electrode active material during cycling, improve the compositional stability of the electrode sheet, and further improve the battery efficiency and cycle performance.

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

[0048] Optionally, the silicon compound accounts for 0.2% to 1% of the total mass.

[0049] By adjusting the mass ratio of silicon compounds in the electrode film, the dehydration and adsorption capacity of the electrode can be improved, while minimizing the adverse effects of silicon compounds on other components in the electrode film.

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

[0051] (6) The positive electrode active material includes any one of the positive electrode active materials of lithium-ion batteries, sodium-ion batteries and potassium-ion batteries.

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

[0053] Optionally, the transition metal includes iron.

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

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

[0056] With the increasingly tight supply of lithium resources, sodium-ion batteries, which have more abundant raw material reserves and lower costs for positive electrode active materials, have come into view. However, compared with the positive electrode active materials of lithium-ion batteries, the positive electrode active materials of traditional sodium-ion batteries are more hygroscopic and more prone to absorbing moisture, which seriously hinders the improvement of sodium-ion battery performance. By adopting the technical solution of this application, the stability of sodium-ion batteries can be improved, 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 them;

[0058] 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 electrode film layer further comprises a conductive agent and a binder;

[0060] Optionally, the mass percentage of the conductive agent in the electrode film is 1% to 20%.

[0061] Optionally, the binder accounts for 1% to 10% of the mass of the electrode film.

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

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

[0064] A second aspect of this application provides a method for preparing the electrode sheet of the first aspect, comprising the following steps:

[0065] A film slurry is coated on the surface of the current collector to form an electrode film, thereby preparing an electrode sheet;

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

[0067] A third aspect of this application provides a battery comprising an electrode sheet prepared by the method of the first aspect or the second aspect.

[0068] The aforementioned batteries exhibit high coulombic efficiency and good cycle performance.

[0069] A fourth aspect of this application provides an electrical device comprising the battery of the third aspect. Attached Figure Description

[0070] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

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

[0072] Figure 2 is an exploded view of Figure 1;

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

[0074] Figure 4 is an exploded view of Figure 3;

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

[0076] Explanation of reference numerals in the attached figures:

[0077] 1. Battery pack; 2. Upper casing; 3. Lower casing; 4. Battery; 41. Housing; 42. Electrode assembly; 43. Cover plate; 5. Electrical device. Detailed Implementation

[0078] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0079] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0080] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0081] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0082] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0083] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0084] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0085] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0086] In this application, the term "alkyl" refers to a group formed by the loss of a hydrogen atom from an alkane, such as methyl formed by the loss of a hydrogen atom from methane; "alkenyl or alkynyl" refers to a group formed by the loss of a hydrogen atom from an alkene or alkynyl, such as vinyl formed by the loss of a hydrogen atom from ethylene, or ethynyl formed by the loss of a hydrogen atom from acetylene.

[0087] The term "alkanes" refers to alkanes in which all carbon atoms are linked by carbon-carbon single bonds and do not form a ring, and the remaining valence bonds are combined with hydrogen. They include straight-chain alkanes and branched-chain alkanes.

[0088] In this application, the number of carbon atoms in "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, and 30. Non-limiting examples include methaneyl, ethaneyl, n-propane, isopropane, n-butane, and isopropane. Butyl, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, n-octyl, n-nonyl, n-decyl.

[0089] In this application, "ring atom number" refers to the number of atoms that form a ring when the ring is replaced by a substituent, and the atoms contained in the substituent are not included in the ring-forming atoms. The same applies to the "ring atom number" mentioned below unless otherwise specified; for example, the ring atom number of benzene is 6, the ring atom number of naphthalene is 10, and the ring atom number of thiophene is 5.

[0090] "Aryl" refers to a hydrocarbon group containing at least one aromatic ring, including non-fused-ring aryl and fused-ring aryl groups. Fused-ring aryl refers to a group formed by two or more aromatic rings linked by two shared adjacent ring atoms, i.e., a fused ring. Non-limiting examples of aryl groups include, but are not limited to, phenyl, naphthyl, anthraceneyl, phenanthryl, biphenyl, terphenyl, benzo[9,10]phenanthryl, pyrene, benzofluoranthracene, etc. Alkyl, dibenzocycloalkyl (such as fluorenyl, dihydroanthracene), etc.

[0091] In this application, "heteroaryl" refers to a compound having a closed-ring conjugated system and containing heteroatoms. The heteroatom can be at least one of boron, oxygen, nitrogen, phosphorus, silicon, and sulfur, and the number of heteroatoms in the heteroaryl group can be one, two, three, four, five, or more. Heteroaryl groups can be monocyclic heteroaryl or fused-ring heteroaryl. It should be understood that a fused aryl (hetero)group with one or more (two or more) carbonyl groups attached to it is also considered a heteroaryl group. Specific examples of heteroaryl groups include, but are not limited to, thiophene, furanyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridyl, triazinyl, acridinel, pyridazinyl, quinolinyl, quinazolinyl, quinoxazinyl, phenoxazinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, isoquinolinyl, indolyl, carbazole, benzoxazolyl, benzimidazolyl, and benzothiazolyl. Azolyl, benzocarbazoyl, benzothiophene, dibenzothiophene, thiophene-thiophene, benzofuranyl, phenanthrolinel, isoxazolyl, thiadiazoyl, phenothiazinyl, phenothiazinyl, dibenzo-p-dioxinyl, quinazolinoneyl, benzothiadiazoyl, benzotriazolyl, thiaanthryl, phenothiazinyl, phenothiazinyl, thiaanthrenetetroxide, phenothiazindioxide, anthraquinoneyl, phenothiazindioxide, thioxanthiumdioxide, etc.

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

[0093] "Alkoxy" refers to a group with the structure -OR, where R is an alkyl group, i.e., an alkyl group as defined above, connected to an adjacent group via an oxygen atom. Phrases containing this term, such as "alkoxy group with 1-30 carbon atoms," mean that the alkyl moiety contains 1-30 carbon atoms. Examples of alkoxy groups 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 this application, halogen groups include chlorine, fluorine, bromine, and iodine.

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

[0096] In summary, the power and cycle performance of traditional rechargeable batteries are increasingly failing to meet current demands. Traditional technologies primarily focus on developing new materials or adjusting the loading of active materials on the electrodes to improve battery efficiency and cycle performance. However, the development of new materials is a lengthy and arduous process, with no substantial progress to date. Furthermore, adjusting the loading of active materials on the electrodes can bring other negative effects; for example, excessive loading can lead to electrode cracking, ultimately limiting the improvement in cycle performance.

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

[0098] One embodiment of this application provides an electrode sheet, which includes a current collector and an electrode film layer disposed on the surface of the current collector. The electrode film layer comprises a silicon compound having a group shown in formula (A):

[0099]

[0100] 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 shown in formula (A) is connected to other structures in the silicon compound.

[0102] In the aforementioned electrode sheet, the silicon compound in the electrode film contains a specific group shown in formula (A). On the one hand, the silicon compound can capture moisture in the electrode film and, when fabricated into a battery, can also capture moisture in the electrolyte, thereby reducing the moisture content in the battery system and minimizing side reactions caused by moisture. On the other hand, when fabricated into a battery, the silicon compound in the electrode sheet can also react with the corrosive byproduct HF generated in the electrolyte, thereby capturing corrosive byproducts such as HF. The combined effect of these two aspects can 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 its own thickness direction, and the electrode film layer is disposed on one or both of the two opposite surfaces of the current collector; furthermore, the above-mentioned electrode film layer can be any functional layer disposed 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 compound and active material, or it can be a newly formed functional layer directly coated with silicon compound.

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

[0105] It can be understood that "*" represents the site where the group shown in formula (A) is connected to other structures in the silicon compound, meaning that at least one electron in the group shown in formula (A) will form a covalent bond with one electron in another structure in the silicon compound.

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

[0107] It is understood that in this application, the range of groups selected for 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, a halogen-substituted alkyl group having 1 to 15 carbon atoms, an unsubstituted cycloalkyl group having 3 to 15 carbon atoms, a halogen-substituted cycloalkyl group having 3 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, an aryl group having 6 to 20 substituted or unsubstituted cyclic atoms, a heteroaryl group having 5 to 20 substituted or unsubstituted cyclic 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, an unsubstituted alkyl group having 1 to 15 carbon atoms, a halogen-substituted alkyl group having 1 to 15 carbon atoms, an unsubstituted cycloalkyl group having 3 to 15 carbon atoms, a halogen-substituted cycloalkyl group having 3 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, an unsubstituted aryl group having 6 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms substituted with a C1 to C5 alkyl group or a halogen, an unsubstituted heteroaryl group having 5 to 20 carbon atoms, a heteroaryl group having 5 to 20 carbon atoms substituted with a C1 to C5 alkyl group or a halogen, an alkenyl group having 2 to 15 carbon atoms, and an alkynyl group having 2 to 15 carbon atoms.

[0110] Optionally, the above-mentioned heteroaryl group contains at least one heteroatom.

[0111] In some embodiments, the heteroatoms in the heteroaromatic group include 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, an unsubstituted alkyl group having 1 to 10 carbon atoms, a halogen-substituted alkyl group having 1 to 10 carbon atoms, an unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a halogen-substituted cycloalkyl group having 3 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an unsubstituted aryl group having 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms substituted with a C1 to C5 alkyl group or a halogen, an unsubstituted heteroaryl group having 5 to 10 carbon atoms, a heteroaryl group having 5 to 10 carbon atoms substituted with a C1 to C5 alkyl group or a halogen, an alkenyl group having 2 to 10 carbon atoms, and an alkynyl group having 2 to 10 carbon atoms.

[0114] In some embodiments, each R1 is independently selected from any one of hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted with a halogen, an unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms substituted with a halogen, an alkoxy group having 1 to 5 carbon atoms, an unsubstituted aryl group having 6 to 5 carbon atoms, an aryl group having 6 to 10 carbon atoms substituted with a C1 to C5 alkyl group or a halogen, an unsubstituted heteroaryl group having 5 to 10 carbon atoms, a heteroaryl group having 5 to 10 carbon atoms substituted with a C1 to C5 alkyl group or a 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, which is selected from at least one group selected from borate, phosphate, phosphinate, sulfonate and amine groups.

[0118] It is understood that the D group and the group shown in formula (A) are connected through the oxygen atom on the D group to form a silyl ester group.

[0119] Optionally, the D group is selected from at least one group selected from borate ester group, phosphate ester group, and phosphinate ester group, wherein the D group and the group shown in formula (A) are connected by an oxygen atom.

[0120] Research has found that when silicon compounds contain borate ester structures, they can participate in the formation of the SEI (or CEI) film when used in battery manufacturing, further improving the film structure, enhancing its toughness, and thus further improving the battery's cycle performance.

[0121] Further research revealed that when the silicon compounds in the electrode sheet also contain phosphate esters or hypophosphite structures, the amount of transition metals dissolved in the active material of the electrode sheet can be reduced during cycling, thereby improving the compositional stability of the electrode sheet and further enhancing 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 phosphonate groups on the surface of the electrode can react with the oxidizing substances generated during the charging and discharging process of the battery, reduce the parasitic oxidation current, inhibit the decomposition effect of the oxidizing substances on the electrode material, and enhance the compositional stability of the electrode during the charging and discharging process.

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

[0124]

[0125] G is selected from boron or phosphorus, and each L1 is independently selected from any one of the following: halogen atom, substituted or unsubstituted alkyl group with 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl group with 3 to 30 carbon atoms, substituted or unsubstituted aryl group with 6 to 50 cyclic atoms, substituted or unsubstituted heteroaryl group with 5 to 50 cyclic atoms, alkenyl group with 2 to 30 carbon atoms, alkynyl group with 2 to 30 carbon atoms, group shown in formula (A), and -OT1, and at least one L1 is -OT1. T1 is selected from any one of the following: hydrogen, group shown in formula (A), substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted heteroaryl group, and unsaturated hydrocarbon group, and at least one T1 is group shown in formula (A).

[0126] It is understood that the silicon compound shown in formula (1) contains at least one group shown in formula (A).

[0127] In some embodiments, each L1 is independently selected from any one of the following: halogen atom, alkyl group having 1 to 15 carbon atoms, alkyl group having 1 to 15 carbon atoms substituted with halogen, cycloalkyl group having 3 to 15 carbon atoms, aryl group having 6 to 30 ring atoms, heteroaryl group having 5 to 25 ring atoms, alkenyl group having 2 to 15 carbon atoms, alkynyl group having 2 to 15 carbon atoms, group shown in formula (A), and -OT1.

[0128] In some embodiments, each L1 is independently selected from any one of the following: halogen atom, alkyl group having 1 to 10 carbon atoms, alkyl group having 1 to 10 carbon atoms substituted with halogen, cycloalkyl group having 3 to 10 carbon atoms, aryl group having 6 to 15 ring atoms, heteroaryl group having 5 to 15 ring atoms, alkenyl group having 2 to 10 carbon atoms, alkynyl group having 2 to 10 carbon atoms, group shown in formula (A), and -OT1.

[0129] In some embodiments, each L1 is independently selected from any one of the following: halogen atom, alkyl group having 1 to 5 carbon atoms, alkyl group having 1 to 5 carbon atoms substituted with halogen, cycloalkyl group having 3 to 6 carbon atoms, aryl group having 6 to 10 ring atoms, heteroaryl group having 5 to 10 ring atoms, alkenyl group having 2 to 5 carbon atoms, alkynyl group having 2 to 5 carbon atoms, group shown in formula (A), and -OT1.

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

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

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

[0133] In some of these embodiments, at least two L1s are selected from -OT1.

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

[0135] Optionally, T1 is selected from any one of hydrogen, the group shown in formula (A), an alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted with 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, the group shown in formula (A), an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted with 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, and at least one T1 is the group shown in formula (A).

[0137] In some embodiments, T1 is selected from any one of hydrogen, the group shown in formula (A), an alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted with 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, and at least one T1 is the group shown in formula (A).

[0138] In some embodiments, T1 is selected from any one of hydrogen, the group shown in formula (A), an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted with 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, and at least one T1 is the group shown in formula (A).

[0139] In some of these embodiments, at least two T1 groups are selected from those shown in formula (A).

[0140] In some of these embodiments, each T1 is selected from the group shown in formula (A).

[0141] Each L2 is independently selected from any one of the following: 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 cyclic atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 cyclic atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group shown in formula (A), and -OT2, and at least one L2 is selected from -OT2, T2 is selected from any one of the following: hydrogen, a group shown in 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 shown in formula (A).

[0142] In other words, formula (2) contains at least one group as shown in formula (A).

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

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

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

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

[0147] In some of these embodiments, the L2s may be the same or different.

[0148] In some of these embodiments, all L2s are identical.

[0149] In some of these embodiments, at least two L2s 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, the group shown in formula (A), an alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted with 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, the group shown in formula (A), an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted with 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, and at least one T2 is the group shown in formula (A).

[0153] In some embodiments, T2 is selected from any one of hydrogen, the group shown in formula (A), an alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted with 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, and at least one T2 is the group shown in formula (A).

[0154] In some embodiments, T2 is selected from any one of hydrogen, the group shown in formula (A), an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted with 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, and at least one T2 is selected from the group shown in formula (A).

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

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

[0157] Y is selected from a single bond or oxygen, and L3 is independently selected from any one of the following: 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 cyclic atoms, a substituted or unsubstituted heteroaryl group having 5 to 50 cyclic atoms, an alkenyl group having 2 to 30 carbon atoms, an alkynyl group having 2 to 30 carbon atoms, a group shown in formula (A), and -OT3, and at least one L3 is -OT3. T3 is selected from any one of the following: hydrogen, a group shown in 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 shown in formula (A).

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

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

[0160] In some embodiments, L3 is independently selected from any one of the following: halogen atom, alkyl group having 1 to 10 carbon atoms, cycloalkyl group having 3 to 10 carbon atoms substituted with halogen, aryl group having 6 to 15 ring atoms, heteroaryl group having 5 to 15 ring atoms, alkenyl group having 2 to 10 carbon atoms, alkynyl group having 2 to 10 carbon atoms, group shown in formula (A), and -OT3.

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

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

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

[0164] Further optionally, at least two T3s are selected from the groups shown in formula (A).

[0165] In some of these embodiments, each T3 is selected from the group shown in formula (A).

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

[0167] In other words, formula (4) contains at least one group as shown in formula (A).

[0168] In some embodiments, each L4 is independently selected from any one of hydrogen, an alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted with 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 a group represented by formula (A).

[0169] In some embodiments, each L4 is independently selected from any one of hydrogen, an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted with 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 a group represented by formula (A).

[0170] In some embodiments, each L4 is independently selected from any one of hydrogen, an alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted with 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 a group represented by formula (A).

[0171] In some embodiments, each L4 is independently selected from any one of hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted with 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 a group represented by formula (A).

[0172] In some of these embodiments, the L4s may be the same or different.

[0173] In some of these embodiments, at least two L4 groups are selected from the group shown in formula (A).

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

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

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

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

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

[0179] In some embodiments, each L5 is independently selected from any one of the following: halogen atom, alkyl group having 1 to 5 carbon atoms, alkyl group having 1 to 5 carbon atoms substituted with halogen, cycloalkyl group having 3 to 6 carbon atoms, aryl group having 6 to 10 ring atoms, heteroaryl group having 5 to 10 ring atoms, alkenyl group having 2 to 5 carbon atoms, alkynyl group having 2 to 5 carbon atoms, group shown in formula (A), and -OT5.

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

[0181] In some of these embodiments, at least two L5s 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, the group shown in formula (A), an alkyl group having 1 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms substituted with 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, the group shown in formula (A), an alkyl group having 1 to 15 carbon atoms, an alkyl group having 1 to 15 carbon atoms substituted with 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, the group shown in formula (A), an alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms substituted with 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, the group shown in formula (A), an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 5 carbon atoms substituted with 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 of these embodiments, at least two T4 groups are selected from those shown in formula (A).

[0188] In some of these embodiments, each T4 is selected from the group shown in formula (A).

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

[0190] Optionally, G is phosphorus.

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

[0192] In some embodiments, the silicon compound includes at least one selected from the following: tris(trimethylsilyl) phosphite, tris(trimethylsilyl) phosphate, di(trimethylsilyl) fluorophosphite, tris(trimethylsilyl) borate, hexamethyldisilazane, di(trimethylsilyl) difluorobiphosphate, 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, di(trimethylsilyl) fluorophosphite, di(trimethylsilyl) difluorobiphosphate, tetra(trimethylsilyl) pyrophosphate, bis(trimethylsilyl) vinyl phosphate, tris(vinyldimethylsilane) phosphate, and tris(phenyldimethylsilane) phosphate.

[0194] In some embodiments, the silicon compound accounts for 0.1% to 1.2% of the mass of the electrode film.

[0195] Optionally, the silicon compound accounts for 0.2% to 1% of the total mass.

[0196] By adjusting the mass ratio of silicon compounds in the electrode film, the dehydration and adsorption capacity of the electrode can be improved, while minimizing the adverse effects of silicon compounds on other components in the electrode film.

[0197] The values ​​in the aforementioned "0.1% to 1.2%" range include the minimum and maximum values ​​of this range, as well as every value between the 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 any range consisting of two values, such as: 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 0.05%. 0.6%, 0.2%–0.7%, 0.2%–0.8%, 0.2%–0.9%, 0.2%–1%, 0.3%–0.4%, 0.3%–0.5%, 0.3%–0.6%, 0.3%–0.7%, 0.3%–0.8%, 0.3%–0.9%, 0.3%–1%, 0.4%–0.5%, 0.4%–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 electrode film layer also includes a positive electrode active material.

[0199] The aforementioned positive electrode active material can be a commonly used positive electrode active material in this application, such as lithium-ion positive electrode active material or sodium-ion positive electrode active material.

[0200] In some embodiments, the positive electrode active material includes any one of the positive electrode active materials for lithium-ion batteries, sodium-ion batteries, and potassium-ion batteries.

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

[0202] With the increasingly tight supply of lithium resources, sodium-ion batteries, which have more abundant cathode materials and lower costs, have come into focus. However, compared to the cathode active materials of lithium-ion batteries, the cathode active materials of traditional sodium-ion batteries are more hygroscopic and more prone to absorbing moisture, which seriously hinders the improvement of sodium-ion battery performance. By adopting the technical solution of this application, the stability of sodium-ion batteries can be improved, thereby improving the coulombic efficiency and cycle performance of sodium-ion batteries.

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

[0204] Transition metals include at least one of chromium, manganese, iron, cobalt, nickel, copper, zinc, palladium, silver, platinum, and gold.

[0205] Optionally, transition metals include iron.

[0206] The positive electrode active materials for lithium-ion batteries, sodium-ion batteries, and potassium-ion batteries are referred to as lithium-ion active materials, sodium-ion active materials, and potassium-ion active materials, respectively, below.

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

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

[0209] It should be noted that the lithium content in the cathode material mentioned above refers to its content when it is not in use. During battery use, it will be repeatedly charged, and the Li in the cathode active material will change during the charging and discharging process. That is, the molar subscript of Li in the cathode active material of 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 represented as Li y Fe x Mn (1-x) PO4, y is 0 to 1.1.

[0211] For example, regarding the ternary material Li y (Ni a Co b Mn c ) 1-d M d O 2-x A z y is 0.2 to 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] During the charging and discharging process, Li will be extracted and consumed. The molar content of Li will be different when the battery is discharged to different states. The above limitation on y includes the molar content of Li in different charging and discharging states of the battery. Furthermore, the battery voltage is usually between 2-5V.

[0213] As an example, sodium-ion active materials may include at least one of the following: sodium transition metal oxides, polyanionic compounds, and Prussian blue compounds. However, this application is not limited to these materials, and other conventionally known materials that can be used as positive electrode active materials for sodium-ion batteries may also be used.

[0214] As an optional technical solution in this application, the transition metal in the sodium transition metal oxide includes at least one selected from Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr, and Ce. For example, the sodium transition metal oxide is Na. x MO2, 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 in this application, the polyanionic compound can be a compound containing sodium ions, transition metal ions, or a tetrahedral (YO4) structure. n- A class of compounds with anionic units. 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- The price state.

[0216] Polyanionic compounds can also contain sodium ions, transition metal ions, or tetrahedral (YO4) ions. n- A class of compounds comprising anionic units and halide anions. 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, where n represents (YO4). n- The valence state; the halogen can be at least one of F, Cl and Br.

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

[0218] Polyanionic compounds include, for example, 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 them.

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

[0220] Prussian blue compounds can contain sodium ions, transition metal ions, and cyanide ions (CN). - A class of compounds. Transition metals include 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 this application, the mass percentage of the positive electrode active material in the electrode film layer is 70% to 99.8%.

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

[0223] Taking the aforementioned electrode sheet as the positive electrode as an example, the conductive agent can be a commonly used conductive agent 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 at least one of 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 adhesive can be at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-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 fluorinated acrylate resins.

[0225] Optionally, the conductive agent accounts for 1% to 20% of the mass of the electrode film.

[0226] Optionally, the binder accounts for 1% to 10% of the mass of the electrode film.

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

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

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

[0230] In any embodiment of this application, the current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer 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 metallic material is selected from any one of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys.

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

[0233] One embodiment of this application also provides a method for preparing an electrode sheet, including the following step S10.

[0234] Step S10: Coat the current collector surface with a film slurry to form an electrode film and prepare an electrode sheet; the film slurry comprises the aforementioned silicon compound.

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

[0236] In any embodiment of this application, taking a positive electrode sheet as an example, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto a current collector, and then obtaining the positive electrode sheet after drying, cold pressing, and other processes. The solid content of the positive electrode slurry is 40wt% to 80wt%, and the viscosity at room temperature is adjusted to 5000mPa·s to 25000mPa·s. The positive electrode slurry is coated onto the surface of the positive electrode current collector, dried, and then cold-pressed using a cold rolling mill to form the positive electrode sheet.

[0237] In some embodiments, the areal density of the positive electrode active material contained in the positive electrode sheet is 0.018 g / cm³. 2 ~0.05g / cm2 .

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

[0239] According to one embodiment of this application, a battery is provided, which includes the electrode sheet described above or the electrode sheet prepared by the above-described electrode sheet preparation method.

[0240] The aforementioned batteries exhibit high coulombic efficiency and good cycle performance.

[0241] In the above-mentioned battery, at least one of the negative electrode or positive electrode is selected from the above-mentioned electrode sheets; 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, wherein the negative electrode sheet, the separator and the electrolyte are described herein in a non-limiting manner.

[0242] [Negative electrode plate]

[0243] The negative electrode 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 negative electrode active materials.

[0245] The aforementioned negative electrode active material can be any commonly used negative electrode active material described in this application.

[0246] In any embodiment of this application, the aforementioned negative electrode active material includes at least one of the following: mesophase carbon microspheres, 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 the following: mesophase carbon microspheres, 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 this application, the battery is a lithium battery, and the mass percentage of the negative electrode active material in the negative electrode active layer is 70% to 100%.

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

[0250] In any embodiment of this application, the aforementioned negative electrode conductive agent can be a commonly used conductive material 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 at least one of 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] Based on the total weight of the negative electrode active layer, the weight ratio of the negative electrode conductive agent in the negative electrode active layer is 0–20 wt%.

[0252] The aforementioned 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), polymethyl methacrylate (PMAA), and carboxymethyl chitosan (CMCS).

[0253] Based on the total weight of the negative electrode active layer, the weight ratio of the negative electrode binder in the negative electrode active layer is 0–30 wt%.

[0254] In any embodiment of this application, the negative electrode active layer may optionally include other additives, such as thickeners, such as sodium carboxymethyl cellulose (CMC-Na). 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 to 15 wt%.

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

[0256] Composite current collectors may include a polymer substrate and a metal layer formed on at least one surface of the polymer substrate. Composite current collectors can be formed by forming a metal material on a polymer substrate.

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

[0258] In some 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 this application, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder, and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto a negative electrode current collector, and then performing processes such as drying and cold pressing to obtain the negative electrode sheet. The negative electrode slurry has a solid content of 30wt% to 70wt% and its viscosity at room temperature is adjusted to 2000 mPa·s to 10000 mPa·s; the obtained negative electrode slurry is coated onto a negative electrode current collector, and after drying and cold pressing (e.g., with rollers), the negative electrode sheet is obtained.

[0260] In some embodiments, the areal density of the negative electrode active material contained in the negative electrode sheet is 0.005 g / cm³. 2 ~0.03g / cm 2 .

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

[0262] The electrolyte exhibits excellent wettability on the electrode, especially when the active material loading and thickness on the electrode are high, it can wet the electrode more quickly, improve the interfacial 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 "sodium battery without a negative electrode", then 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 a substantial sense. After the battery is assembled and 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, thus obtaining a true negative electrode.

[0264] [Isolation membrane]

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

[0266] This application does not impose any particular restrictions on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

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

[0268] The thickness of the diaphragm is controlled between 2 μm and 15 μm; optionally, the thickness of the diaphragm is controlled between 2 μm and 13 μm.

[0269] Electrolyte

[0270] Electrolytes consist of electrolyte salts and solvents.

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

[0272] As an example, lithium-ion electrolyte salts include, but are not limited to, one or more of the following: 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 difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0273] As an example, sodium ion electrolyte salts include, but are not limited to, one or more of the following: sodium hexafluorophosphate, sodium difluorooxalate borate, sodium tetrafluoroborate, sodium dioxalate borate, sodium perchlorate, sodium hexafluoroarsenate, sodium bis(fluorosulfonyl)imide, sodium trifluoromethanesulfonate, and sodium bis(trifluoromethanesulfonyl)imide.

[0274] In some embodiments, the solvent may be selected from fluoroethylene carbonate (FEC), ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl 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, etc. One or more of the following: ester (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (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, and crown ether.

[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 aforementioned ether solvent molecules can construct a stable electrode / electrolyte interface on the surface of a sodium metal anode (including anode-free anode, the anode design in this application is anode-free anode), forming a stable solid electrolyte interface (SEI) and reducing electrochemical polarization.

[0277] In some implementations, the concentration of the electrolyte salt in the electrolyte is typically 0.5 mol / L.

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

[0279] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature 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 above-mentioned battery is a sodium-ion battery without a negative electrode.

[0282] This application does not impose any particular limitation on the shape of the battery; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 1 shows a square battery 4 as an example.

[0283] In some embodiments, referring to FIG2, the housing may include a housing 41 and a cover plate 43. The housing 41 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 41 has an opening communicating with the receiving cavity, and the cover plate 43 is capable of covering the opening to close the receiving cavity.

[0284] The positive electrode, negative electrode, and separator can be formed into electrode assembly 42 by a winding or stacking process. Electrode assembly 42 is encapsulated within a receiving cavity. Electrolyte is immersed in electrode assembly 42. The battery 4 can contain one or more electrode assemblies 42, which can be adjusted according to requirements.

[0285] This application also provides an electrical device that includes the battery described above.

[0286] Furthermore, in the aforementioned electrical device, the battery can exist in the form of a single battery cell, or it can be further assembled into a battery pack.

[0287] Figures 3 and 4 show a battery pack 1 as an example. The battery pack 1 includes a battery compartment and one or more batteries 4 disposed within the battery compartment. The battery compartment includes an upper compartment 2 and a lower compartment 3, the upper compartment 2 being able to cover the lower compartment 3 and form an enclosed space for the batteries 4.

[0288] Multiple batteries 4 can be arranged in the battery box in any way.

[0289] The aforementioned battery or the battery pack assembled therefrom can be used as a power source for an electrical device or as an energy storage unit for an electrical device.

[0290] The aforementioned electrical devices may include, 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 shows an example of an electrical device 5. This electrical device 5 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of the secondary battery for this electrical device 5, a battery pack can be used.

[0292] Another example of an electrical device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use batteries as their power source.

[0293] The present invention will now be described with reference to specific embodiments. However, the present invention is not limited to the embodiments described below. It should be understood that the appended claims summarize the scope of the present invention. Under the guidance of the inventive concept, those skilled in the art should realize that any 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 examples.

[0295] Example 1

[0296] S1, Preparation of sodium batteries

[0297] (1) Preparation of positive electrode sheet

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

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

[0300] The thickness of the active layer in the positive electrode was tested: specifically, the thickness of the positive electrode and the current collector was measured by a 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 using infrared spectroscopy. The results showed a characteristic peak of trimethylsilyl (TMS) group, and the molecular weight of the components was quantified based on the intensity of the contrast absorption peaks in the infrared spectrum. The types of silicon compounds and their mass percentage (H1) in the active layer are shown in Table 1.

[0302] The water content in the active layer of the positive electrode was determined using a KF-type trace moisture analyzer. The specific steps were performed according to 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] Sodium carboxymethyl cellulose (CMC) binder and carbon nanotubes conductive agent were mixed in water at a mass ratio of 3:2 and stirred to form a uniform slurry with a solid content of 2%. The slurry was coated on the surface of copper foil and then transferred to a vacuum drying oven for complete drying. After cutting, the negative electrode sheet was obtained, and the thickness of the slurry layer formed was 1.2 μm.

[0305] (3) Preparation of electrolyte

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

[0307] (4) Separation membrane: Polypropylene membrane is used as the separation membrane.

[0308] (5) Preparation of sodium battery: The above positive electrode, separator and negative electrode are stacked in sequence, with the separator between the positive electrode and the negative electrode current collector to play a role in isolation. The above electrolyte is added to assemble the stacked battery.

[0309] S2, performance test of sodium battery:

[0310] 1. Coulomb efficiency

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

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

[0313] 2. Recycling capacity retention rate

[0314] The sodium battery was charged at 45°C with a constant current of 1C to 3.7V, then charged at a constant voltage of 3.7V until the current dropped to 0.05C, and then discharged with a constant current of 1C to 2.5V, yielding the initial discharge capacity Cd1. This charging and discharging process was repeated until the nth cycle, yielding the discharge capacity of the sodium battery after n cycles, denoted as Cdn. The capacity retention rate of the sodium battery was then calculated using the following formula:

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

[0316] 3. Monitoring of sodium dendrite growth

[0317] Take the sodium battery after 200 cycles in the cycle test in 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 formed: no white spots on the negative electrode indicate no sodium dendrites, a few scattered white spots indicate slight sodium dendrites, and a dense array of white spots indicates severe sodium dendrites.

[0318] 4. Take the sodium battery that has undergone 200 cycles in the cycle test in step 2 above, disassemble the sodium battery in an argon atmosphere glove box (H2O<0.1ppm, O2<0.1ppm), make the negative electrode into a small disc, and after digestion treatment, perform ICP-MS test to analyze the content of transition metal Fe on the negative electrode after 200 cycles. This can be regarded as the amount of transition metal Fe dissolved in the positive electrode, and recorded as F0.

[0319] Examples 2-14

[0320] Examples 2-14 are basically the same as Example 1, except that in step (1), the type of silicon compound or its mass ratio in the active layer is different from that in Example 1. Specifically, when adjusting the mass ratio of silicon compound, the mass ratio of silicon compound and binder is adjusted separately while maintaining the total mass ratio of silicon compound and binder, so that the mass ratio of silicon compound is different from that in Example 1, while the mass ratio of other components is the same as that in Example 1. See Table 1 for specific parameters.

[0321] The other steps and conditions are the same as 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), no silicon compound is added in the preparation of the positive electrode sheet, and the mass ratio of positive electrode active material, conductive agent and polyvinylidene fluoride binder is 80:10:10. For specific parameters, please refer to Table 1.

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

[0325] Comparative Example 2

[0326] Comparative Example 2 is basically the same as Comparative Example 1, except that in step (1), the silicon compound is replaced with an equal mass of sodium dodecylbenzenesulfonate. For specific parameters, please refer to Table 1.

[0327] The other steps and conditions are the same as those in Comparative Example 1. The test results are shown in Table 1.

[0328] Comparative Example 3

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

[0330] The relevant parameters and performance results of each embodiment and comparative example are shown in Table 1. Here, the mass percentage of silicon compound in the active layer is H1, and the amount of Fe dissolved from the positive electrode is denoted as F0.

[0331] Table 1

[0332]

[0333]

[0334] Note: In Table 1, " / " indicates that the substance or parameter does not exist.

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

[0336] Furthermore, comparing the results of Example 1 and Comparative Example 3, it can be seen that by using the technical solution of this application, adding silicon compounds containing specific groups to the electrode film layer can simultaneously achieve the functions of water removal and effective inhibition of metal dissolution, while silicon compounds in the electrolyte only play a simple water removal role.

[0337] Studies have shown that the reason for the above phenomenon may be that the phosphate or phosphonate 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 compositional 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 embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above 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 embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A sodium-ion battery, characterized in that, The sodium-ion battery includes an electrode sheet, the electrode sheet including a current collector and an electrode film layer disposed on the surface of the current collector, the electrode film layer comprising a silicon compound, the silicon compound including at least one of formulas (1) to (5): In this formula (5), G is selected from boron or phosphorus; each L1 is independently selected from either an F atom or -OT1, and at least one L1 is -OT1; T1 is selected from the group shown in formula (A); each L2 is independently selected from either an F atom, vinyl group, or -OT2, and at least one L2 is -OT2; T2 is selected from the group shown in formula (A); Y is selected from a single bond or oxygen; each L3 is independently selected from either an F atom or -OT3, and at least one L3 is -OT3; T3 is selected from the group shown in formula (A); each L4 is independently selected from either hydrogen, methyl, ethyl, or the group shown in formula (A), and at least one L4 is the group shown in formula (A); of the two L5s in formula (5), one L5 is methyl, the other L5 is -OT4, and T4 is selected from the group shown in formula (A); the group shown in formula (A): In formulas (1), (3) to (5), each R1 is methyl; in formula (2), each R1 is independently selected from methyl, vinyl or phenyl, and at least two R1 are methyl; "*" represents the site where the group shown in formula (A) is connected to other structures in the silicon compound.

2. The sodium-ion battery as described in claim 1, characterized in that, At least two L1s are selected from -OT1, and at least two T1s are selected from the group shown in formula (A).

3. The sodium-ion battery as described in claim 1, characterized in that, At least two L2s are selected from -OT2, and at least two T2s are selected from the group shown in formula (A).

4. The sodium-ion battery as described in claim 1, characterized in that, At least two L3s are selected from -OT3, and at least two T3s are selected from the group shown in formula (A).

5. The sodium-ion battery as described in claim 1, characterized in that, At least two L4 groups are selected from the group shown in formula (A).

6. The sodium-ion battery as described in claim 1, characterized in that, G stands for phosphorus.

7. The sodium-ion battery according to any one of claims 1 to 6, characterized in that, The silicon compound includes at least one of tris(trimethylsilyl)borate, tris(trimethylsilyl) phosphate, tris(trimethylsilyl) phosphite, di(trimethylsilyl) difluorobiphosphate, tetra(trimethylsilyl) pyrophosphate, di(trimethylsilyl) fluorophosphite, di(trimethylsilyl) difluorophosphate, hexamethyldisilazane, bis(trimethylsilyl)vinyl phosphate, tris(vinyldimethylsilane) phosphate, tris(phenyldimethylsilane) phosphate, trimethylsilylmethanesulfonate, heptamethyldisilazane, and ethylhexamethyldisilazane.

8. The sodium-ion battery according to any one of claims 1 to 6, characterized in that, The silicon compound includes at least one of the following: tris(trimethylsilyl) phosphite, tris(trimethylsilyl) phosphate, di(trimethylsilyl) fluorophosphite, tris(trimethylsilyl) borate, hexamethyldisilazane, di(trimethylsilyl) difluorobiphosphate, tetra(trimethylsilyl) pyrophosphate, bis(trimethylsilyl) vinyl phosphate, tris(vinyldimethylsilane) phosphate, tris(phenyldimethylsilane) phosphate, and trimethylsilyl methanesulfonate.

9. The sodium-ion battery as described in claim 8, characterized in that, The silicon compound includes at least one of tris(trimethylsilyl) phosphite, tris(trimethylsilyl) phosphate, di(trimethylsilyl) fluorophosphite, di(trimethylsilyl) difluorobiphosphate, tetra(trimethylsilyl) pyrophosphate, bis(trimethylsilyl) silylated vinyl phosphate, tris(vinyldimethylsilane) phosphate, and tris(phenyldimethylsilane) phosphate.

10. The sodium-ion battery according to any one of claims 1 to 6, characterized in that, In the electrode film, the silicon compound accounts for 0.1% to 1.2% of the total mass.

11. The sodium-ion battery as described in claim 10, characterized in that, In the electrode film, the silicon compound accounts for 0.2% to 1% of the mass.

12. The sodium-ion battery according to any one of claims 1 to 6, characterized in that, The electrode film also includes a positive electrode active material, which contains transition metal elements.

13. The sodium-ion battery as described in claim 12, characterized in that, The transition metal elements include iron.

14. The sodium-ion battery as described in claim 12, characterized in that, In the electrode film layer, the mass percentage of the positive electrode active material is 70% to 99.8%.

15. The sodium-ion battery as described in claim 12, characterized in that, The positive electrode active material includes NaFePO4, Na3V2(PO4)3, Na4Fe3(PO4)2(P2O7), NaM1PO4F, and Na a M2 b M3 c (CN)6 and Na3(VO y )2(PO4)2F (3-2y) At least one of the following: 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.

16. The sodium-ion battery according to any one of claims 1 to 6, characterized in that, The electrode film also includes conductive agents and binders.

17. The sodium-ion battery as described in claim 16, characterized in that, In the electrode film layer, the conductive agent accounts for 1% to 20% by mass; and / or, in the electrode film layer, the binder accounts for 1% to 10% by mass.

18. The sodium-ion battery according to any one of claims 1 to 6, characterized in that, The water content of the electrode film is ≤400ppm.

19. The sodium-ion battery according to any one of claims 1 to 6, characterized in that, The water content of the electrode film is ≤350ppm.

20. The method for preparing a sodium-ion battery according to any one of claims 1 to 19, characterized in that, The process includes the following steps: coating a film slurry onto the surface of a current collector to form an electrode film and preparing an electrode sheet; the film slurry comprises the silicon compound.

21. An electrical appliance, characterized in that, The electrical device includes a sodium-ion battery as described in any one of claims 1 to 19.

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