Metal battery and electric device

Abstract

A metal battery and an electric device. The metal battery comprises a positive electrode sheet, a negative electrode sheet, and a separator, the separator comprises a substrate and at least one bonding layer provided on the surface of the substrate, and the bonding layer at least comprises a first bonding layer provided between the substrate and the negative electrode sheet and / or a second bonding layer provided between the substrate and the positive electrode sheet; on the basis of the total mass of the separator, the fluorine content of the first bonding layer is less than or equal to 500 ppm; and on the basis of the total mass of the separator, the fluorine content of the second bonding layer is less than or equal to 1200 ppm. By rationally designing the fluorine content of a bonding layer of a separator in the metal battery, the discharge gram capacity and the initial coulombic efficiency of the metal battery are improved, and good cycle performance is also achieved.

Description

Metal batteries and electrical devices

[0001] Cross-references

[0002] This application incorporates Chinese Patent Application No. 202410946393.9, filed on July 15, 2024, entitled “Metal Battery and Electrical Device”, which is incorporated herein by reference in its entirety. Technical Field

[0003] This application relates to the field of secondary battery technology, and more particularly to a metal battery and an electrical device. Background Technology

[0004] In recent years, rechargeable batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, as well as in power tools, electric bicycles, electric motorcycles, electric cars, military equipment, aerospace, and many other fields. Compared to traditional rechargeable batteries, metal batteries are gradually gaining attention due to their higher charge-discharge rate performance. To meet people's electricity needs, further improving the electrical performance of metal batteries is of great significance. Summary of the Invention

[0005] This application was made in view of the aforementioned issues and aims to at least solve one of the technical problems existing in the prior art. To this end, this application provides a metal battery and an electrical device. By rationally designing the fluorine content of the separator adhesive layer in the metal battery, this application improves the discharge specific capacity and initial coulombic efficiency of the metal battery, while also exhibiting better cycle performance.

[0006] The first aspect of this application provides a metal battery, the metal battery including a positive electrode, a negative electrode and a separator, the separator including a substrate and at least one adhesive layer disposed on the surface of the substrate, the adhesive layer including at least a first adhesive layer disposed between the substrate and the negative electrode and / or a second adhesive layer disposed between the substrate and the positive electrode;

[0007] Based on the total mass of the separator membrane, the fluorine content of the first adhesive layer is less than or equal to 500 ppm.

[0008] Based on the total mass of the separator membrane, the fluorine content of the second adhesive layer is less than or equal to 1200 ppm.

[0009] In metal batteries, metal elements in the positive electrode active material release metal ions, such as sodium or lithium ions. These metal ions are reduced and deposited on the negative electrode as metal. Furthermore, the metal can be oxidized and dissolved back into metal ions, thus completing the charge-discharge cycle. To fix the interface and prevent dendrite penetration, an adhesive layer can be provided on the separator side. However, metal batteries with this design have low discharge capacity, initial coulombic efficiency, and cycle performance. Furthermore, this application finds that the fluorine-containing groups of the binder in the adhesive layer readily undergo reduction reactions with the metal on the negative electrode. For example, the first adhesive layer directly contacts the deposited metal on the negative electrode, causing a direct side reaction. The fluorine-containing binder in the second adhesive layer readily dissolves in the electrolyte solvent and can penetrate the separator to reach the negative electrode side, reacting with the deposited metal on the negative electrode, thus consuming the metal on the negative electrode and reducing the discharge capacity and cycle performance of the metal battery. This application reduces the concentration of the fluorine in the electrolyte solvent by providing at least a first adhesive layer and / or a second adhesive layer on the surface of the separator substrate, and controlling the fluorine content of the second adhesive layer to be below 1200 ppm, thereby reducing the degree of side reaction between the fluorine and the metal deposited on the negative electrode; and / or, by controlling the fluorine content of the first adhesive layer to be less than or equal to 500 ppm, the degree of side reaction between the fluorine and the metal deposited on the negative electrode sheet in direct contact is reduced. This application, through the rational design of the fluorine content of the separator adhesive layer, improves the discharge specific capacity and initial coulombic efficiency of the metal battery, while also exhibiting good cycle performance.

[0010] In any embodiment, the fluorine content of the first adhesive layer is equal to 0 ppm, based on the total mass of the separator membrane; and / or, the fluorine content of the second adhesive layer is less than or equal to 500 ppm, based on the total mass of the separator membrane.

[0011] When the fluorine content of the second binder layer in this application is further reduced, it is beneficial to further reduce the amount of fluorine-containing substances dissolved in the electrolyte, thereby reducing the degree of side reaction with the negative electrode metal and reducing metal loss. When the fluorine content of the first binder layer in this application is 0, side reactions with the metal deposited on the negative electrode sheet in direct contact can be avoided, reducing metal loss. Through the above-mentioned further optimization of the fluorine content, it is helpful to further improve the discharge specific capacity, initial coulombic efficiency and cycle performance of the metal battery of this application.

[0012] In any embodiment, the positive electrode includes a positive electrode film layer, the positive electrode film layer includes a positive electrode active material, the positive electrode active material includes a metal element, during charging, the positive electrode active material releases metal ions, the metal ions are reduced and precipitated as metal on the negative electrode, and during discharging, the metal is oxidized and dissolved as metal ions.

[0013] In any embodiment, the first adhesive layer includes a first adhesive, and the second adhesive layer includes a second adhesive. The first adhesive and the second adhesive each independently include at least one of the following: methyl methacrylate monomer copolymers and / or homopolymers, sugar monomer copolymers and / or homopolymers, acrylic monomer copolymers and / or homopolymers, styrene monomer copolymers and / or homopolymers, butadiene monomer copolymers and / or homopolymers, phenolic monomer copolymers and / or homopolymers, aldehyde monomer copolymers and / or homopolymers, diamine monomer copolymers and / or homopolymers, dianhydride monomer copolymers and / or homopolymers, benzene ring monomer copolymers and / or homopolymers, or derivatives thereof, or modifiers thereof.

[0014] In any embodiment, the first adhesive and the second adhesive each independently comprise at least one of polymethyl methacrylate, carboxymethyl cellulose, polyacrylic acid, sodium alginate, styrene-butadiene rubber, polyvinyl alcohol, phenolic resin, polyimide, styrene monomer-butadiene monomer-styrene monomer block copolymer, or derivatives thereof, or modifiers thereof.

[0015] The aforementioned types of binders provide adhesive properties for forming the first and second adhesive layers. Furthermore, the fluorine content of these binders meets the requirements of this application, which is beneficial for further improving the initial coulombic efficiency of the metal battery while maintaining good cycle performance.

[0016] In any embodiment, the first adhesive layer includes a third adhesive; and / or, the second adhesive layer includes a fourth adhesive, wherein the third adhesive and the fourth adhesive each independently include at least one of a fluorinated monomer copolymer and / or homopolymer, or a derivative thereof, or a modifier thereof.

[0017] In any embodiment, the third adhesive and the fourth adhesive each independently comprise at least one of the following: vinylidene fluoride monomer copolymers and / or homopolymers, hexafluoropropylene monomer copolymers, fluoroethylene monomer copolymers, trifluoroethylene monomer copolymers, perfluoromethyl isopropyl ether monomer homopolymers, tetrafluoroethylene monomer copolymers, fluoroethylene ester monomer copolymers, methyl methacrylate monomer copolymers, fluorostyrene monomer copolymers, or fluorobenzene monomer copolymers, or derivatives thereof, or modifiers thereof.

[0018] In any embodiment, the third adhesive and the fourth adhesive each independently comprise at least one of vinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trifluoroethylene, polyperfluoromethyl isopropyl ether, polyvinylidene fluoride-tetrafluoroethylene, polyacrylate-fluoroethylene ester, polymethyl methacrylate-fluorostyrene, polystyrene-fluorostyrene, polyester-fluoroethylene ester, polyimide-fluorobenzene, or their derivatives or modifiers.

[0019] When the fluorine content design of the first and second adhesive layers of this application is met, the first and / or second adhesive layers may also include a third and / or fourth adhesive agent made of fluorinated copolymers and / or homopolymers. Adding adhesives of the above types to the first and / or second adhesive layers helps to increase the adhesive properties of the adhesive layers.

[0020] In any embodiment, the mass ratio of the first adhesive to the third adhesive is (1-0.5):(0:0.5); and / or, the mass ratio of the second adhesive to the fourth adhesive is (1-0):(0-1).

[0021] Controlling the mass ratio of the first adhesive to the third adhesive in the first adhesive layer within a suitable range, and / or controlling the mass ratio of the second adhesive to the fourth adhesive in the second adhesive layer within a suitable range, helps to further balance the bonding performance of the first adhesive layer and the second adhesive layer with the discharge capacity, initial coulombic efficiency and cycle performance of the metal battery.

[0022] In any embodiment, the unit area mass of the first adhesive layer is 0-0.3 mg / cm². 2 ; and / or, the unit area mass of the second adhesive layer is 0-0.3 mg / cm³. 2 Wherein, the unit area mass of the first adhesive layer and the second adhesive layer is not both 0 mg / cm³. 2 .

[0023] Controlling the unit area mass of the first adhesive layer and / or the unit area mass of the second adhesive layer within a suitable range helps to improve the interfacial adhesion performance, enhance the liquid absorption and retention capacity of the separator, and also enables the separator to have a suitable ion transport distance, thereby optimizing the kinetic performance of the metal battery.

[0024] In any embodiment, the negative electrode is an inert material that does not participate in the electrochemical reaction.

[0025] Compared to metal anodes, the anode of a electrodeless metal battery does not include anode active material. Electron transfer can be accomplished by the reduction and deposition of metal deposited on the current collector surface by metal ions extracted from the cathode active material. Therefore, the consumption of metal deposited on the anode in an electrodeless metal battery has a greater impact on the discharge specific capacity and initial coulombic efficiency of the metal battery. When the anode of the metal battery in this application is an inert material that does not participate in the electrochemical reaction, i.e., an electrodeless anode, the fluorine content design of the adhesive layer in the separator of this application helps to better improve the discharge specific capacity and initial coulombic efficiency of the metal battery.

[0026] In any embodiment, the negative electrode sheet includes a porous layer formed on the surface of the negative electrode sheet, the porous layer having micron, submicron, or nano-scale pores.

[0027] The porous layer has a large specific surface area, which is beneficial for providing a larger deposition specific surface area for metal ions extracted from the positive electrode active material. This results in more uniform precipitation of the metal ions on the negative electrode sheet, effectively reducing the formation of dendrites in the negative electrode. In addition, the porous layer also helps to shorten the migration distance of metal ions during charging and discharging, which helps to reduce diffusion resistance problems during the reaction process.

[0028] In any embodiment, the porous layer comprises a carbon-based material.

[0029] In any embodiment, the carbon-based material includes at least one of carbon black, activated carbon, carbon nanotubes, carbon fibers, or graphite.

[0030] When the porous layer includes carbon-based materials, the negative electrode sheet has better electronic conductivity. At the same time, the surface of carbon-based materials generally has functional groups such as -COOH and -OH. These functional groups have a better affinity for metals, especially sodium metal, which can be controlled to form a better deposition morphology.

[0031] In any embodiment, the positive electrode film layer includes a positive electrode film layer binder, and the fluorine content of the positive electrode sheet is less than or equal to 385 ppm, based on the total mass of the positive electrode film layer.

[0032] The metal battery includes an electrolyte, and the difference between the lowest unoccupied molecular orbital energy level LUMO2 of the solvent in the electrolyte and the lowest unoccupied molecular orbital energy level LUMO1 of the metallic state corresponding to the metal element in the positive electrode active material is y = LUMO2 energy level - LUMO1 energy level, 0 ≤ y.

[0033] The electrolyte solvent and the metallic state corresponding to the metal element in the positive electrode active material have a suitable LUMO energy level relationship, which helps to reduce the degree of side reactions with the negative electrode metal, thus making it more compatible with the negative electrode and improving the electrical performance of the metal battery. Furthermore, by controlling the fluorine content of the positive electrode sheet to be less than or equal to 385 ppm, this application helps to further reduce the concentration of fluorine-containing substances dissolved in the positive electrode sheet in the electrolyte solvent, thereby reducing the degree of side reactions with the negative electrode metal, further reducing metal consumption, and further improving the discharge capacity, initial coulombic efficiency, and cycle performance of the metal battery.

[0034] In any embodiment, based on the total mass of the positive electrode film, the fluorine content of the positive electrode sheet is less than or equal to 120 ppm.

[0035] When the fluorine content of the positive electrode sheet of this application is further reduced, it is beneficial to further reduce the fluorine-containing substances dissolved in the electrolyte solvent, thereby reducing the side reaction with the negative electrode metal, reducing metal loss, and further improving the discharge specific capacity, initial coulombic efficiency and cycle performance of the metal battery of this application.

[0036] In any implementation, 0.7 ≤ y.

[0037] Further control over the relationship between the metal state corresponding to the metal element in the positive electrode active material and the lowest unoccupied molecular orbital energy level difference of the electrolyte solvent is beneficial to further improve the compatibility between the electrolyte and the negative electrode, and improve the discharge specific capacity and initial coulombic efficiency of the metal battery of this application.

[0038] In any embodiment, the positive electrode film layer binder includes a fifth binder, which is a copolymer and / or a homopolymer, wherein the monomers of the copolymer and the homopolymer have fluorine-containing substituents of less than or equal to 2.

[0039] In the positive electrode of this application, the fluorine-containing substances that are easily dissolved in the electrolyte solvent are mainly binders. Controlling the number of fluorine-containing substituents in the fifth binder helps to balance the bonding performance of the fifth binder and reduce the amount of fluorine-containing groups dissolved in the electrolyte solvent, thereby helping to further reduce the side reactions between the fluorine-containing groups and the negative electrode metal, reduce metal loss, and further improve the discharge specific capacity, initial coulombic efficiency, and cycle performance of the metal battery of this application.

[0040] In any embodiment, the fifth binder comprises at least one of the following: methyl methacrylate monomer copolymers and / or homopolymers, sugar monomer copolymers and / or homopolymers, acrylic monomer copolymers and / or homopolymers, styrene monomer copolymers and / or homopolymers, butadiene monomer copolymers and / or homopolymers, phenolic monomer copolymers and / or homopolymers, aldehyde monomer copolymers and / or homopolymers, diamine monomer copolymers and / or homopolymers, dianhydride monomer copolymers and / or homopolymers, benzene ring monomer copolymers and / or homopolymers, or derivatives thereof, or modifiers thereof.

[0041] In any embodiment, the fifth adhesive comprises at least one of polymethyl methacrylate, carboxymethyl cellulose, polyacrylic acid, sodium alginate, styrene-butadiene rubber, polyvinyl alcohol, phenolic resin, polyimide, styrene monomer-butadiene monomer-styrene monomer block copolymer, or its derivatives or modifiers.

[0042] When the positive electrode film binder includes the aforementioned fifth binder, it provides better adhesion performance for forming the positive electrode film. Simultaneously, the fluorine content of the aforementioned fifth binder meets the requirements of this application; specifically, when the positive electrode film includes the aforementioned fifth binder, the fluorine content of the positive electrode sheet meets the requirements of this application. The application of the aforementioned fifth binder in the positive electrode film of this application helps to further reduce the amount of fluorine-containing groups in the electrolyte solvent, thereby helping to further reduce the side reactions between the fluorine-containing groups and the negative electrode metal, reducing metal loss, and further improving the initial coulombic efficiency and cycle performance of the metal battery of this application.

[0043] In any embodiment, the positive electrode film layer binder includes a sixth binder, which includes at least one of a fluorinated monomer copolymer and / or homopolymer, or a derivative thereof, or a modifier thereof.

[0044] When the fluorine content of the positive electrode sheet in this application is less than or equal to 385 ppm, the positive electrode film binder in this application may also include a sixth binder of fluorinated copolymers and / or homopolymers. Adding a sixth binder of the above type to the positive electrode film binder helps to increase the adhesion performance of the positive electrode film binder.

[0045] In any embodiment, the mass ratio of the fifth adhesive to the sixth adhesive is (1-0.5):(0-0.5).

[0046] In any embodiment, when the mass ratio of the fifth binder to the sixth binder is greater than or equal to 0.5:0.5 and less than 0.6:0.4, the mass percentage of the positive electrode film layer binder, based on the total mass of the positive electrode film layer, is less than or equal to 2% and greater than or equal to 0.5%; and / or

[0047] When the mass ratio of the fifth binder to the sixth binder is greater than or equal to 0.6:0.4 and less than 0.7:0.3, the mass percentage of the binder in the positive electrode film layer, based on the total mass of the positive electrode film layer, is less than or equal to 2.5% and greater than or equal to 0.5%; and / or

[0048] When the mass ratio of the fifth binder to the sixth binder is (1-0.7):(0-0.3), the mass percentage of the binder in the positive electrode film layer is less than or equal to 3% and greater than or equal to 0.5% based on the total mass of the positive electrode film layer.

[0049] Controlling the fifth and sixth binders within a suitable range helps to further balance the bonding performance of the positive electrode film binder and the discharge specific capacity, initial coulombic efficiency, and cycle performance of the metal battery of this application.

[0050] In any embodiment, the mass percentage of the positive electrode film layer binder is less than or equal to 3% and greater than or equal to 0.5% based on the total mass of the positive electrode film layer.

[0051] Controlling the content of the binder in the positive electrode film layer within a suitable range helps to provide suitable bonding performance while reducing the fluorine content of the positive electrode sheet. This helps to further reduce the capacity degradation of the metal battery of this application and improve its initial coulombic efficiency and cycle performance.

[0052] In any embodiment, the electrolyte comprises a solvent and a sodium salt dissolved in the solvent, wherein the solvent comprises at least one ether compound of formula I, R1-(O-R3). n -O-R2 (I)

[0053] R1 and R2 are each independently selected from C1-C6 alkyl groups, R3 is selected from C1-C6 alkylene groups, and n is selected from integers from 1 to 5.

[0054] Unlike conventionally used ester-based electrolyte solvents, the electrolyte solvents of the above general formula meet the LUOM energy level requirements of this application and have good compatibility with the negative electrode sheet of this application.

[0055] In any embodiment, R1 and R2 are each independently selected from methyl or ethyl, and R3 is selected from straight-chain C1-C5 alkylene groups.

[0056] In any implementation, R3 is selected from -CH2CH2-.

[0057] When the electrolyte of the metal battery of this application contains the above-mentioned solvent, the secondary battery of this application has a more stable electrolyte window.

[0058] In any embodiment, the solvent includes at least one of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, pentaethylene glycol diethyl ether, or ethylene glycol dibutyl ether.

[0059] When the electrolyte of the metal battery of this application contains the above-mentioned solvent, the electrolyte of this application has better reduction stability and better interface compatibility with the negative electrode of the metal battery, especially sodium metal battery.

[0060] In any embodiment, the metal battery includes a sodium metal battery.

[0061] Through research, this application found that fluorine-containing groups have a stronger reactivity with sodium-deposited metal. Therefore, the fluorine-containing groups in the first adhesive layer of the separator, the fluorine-containing groups in the second adhesive layer dissolved in the electrolyte solvent, and / or the fluorine-containing groups in the positive electrode film binder cause more severe consumption of sodium-deposited metal on the negative electrode. Therefore, when the metal battery of this application is a sodium metal battery, the design of the fluorine content in the adhesive layer of the separator and / or the fluorine content in the positive electrode helps to better improve its discharge capacity, initial coulombic efficiency, and cycle performance.

[0062] In any embodiment, the positive electrode active material includes Na. a1 Ni b1 Fe c1 Mn d1 M1 e1 O f1 Na x1 M2 y1 M3 y2 (X a2 O b2 ) z1 Z w1 Prussian blue, Prussian white, or at least one of their modified compounds, wherein,

[0063] M includes at least one of active and / or inert doped metal elements, 0.85≤a1≤1, 0≤b1≤1, 0≤c1≤1, 0≤d1≤1, 0≤e1≤1, 1.8≤f1≤2, where b1, c1, d1 and e1 are not simultaneously 0;

[0064] M2 includes at least one of Ti, V, Cr, Mn, Fe, Ca, Mg, Al, Nb, Co, and Zr; M3 includes Ni; X includes at least one of Si, S, P, As, B, Mo, W, and Ge; Z includes at least one of F, O, and OH; 1≤x1≤7, 1≤y1≤4, 0≤y2≤0.05, 0.2≤a2 / b2≤0.3, 1≤z1≤4, and 0≤w1≤7.

[0065] A second aspect of this application provides a method for preparing the metal battery described in this application.

[0066] A third aspect of this application provides an electrical device comprising the metal battery described in this application.

[0067] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0068] Figure 1 is a schematic diagram of a secondary battery according to an embodiment of this application.

[0069] Figure 2 is an exploded view of a secondary battery according to an embodiment of this application shown in Figure 1.

[0070] Figure 3 is a schematic diagram of a battery module according to one embodiment of this application.

[0071] Figure 4 is a schematic diagram of a battery pack according to one embodiment of this application.

[0072] Figure 5 is an exploded view of the battery pack of one embodiment of this application shown in Figure 4.

[0073] Figure 6 is a schematic diagram of an electrical device using a secondary battery as a power source according to an embodiment of this application.

[0074] Explanation of reference numerals in the attached drawings: 1 Battery pack; 2 Upper housing; 3 Lower housing; 4 Battery module; 5 Secondary battery; 51 Housing; 52 Electrode assembly; 53 Top cover assembly. Detailed Implementation

[0075] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the positive electrode active material, its manufacturing method, positive electrode sheet, secondary battery, battery module, battery pack, and electrical device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0076] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0077] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0078] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0079] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0080] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0081] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0082] Compared to traditional rechargeable batteries, metal batteries are gradually gaining attention due to their superior charge / discharge rate performance. To fix the interface and prevent dendrite penetration, adhesive layers can be placed on both sides of the separator; however, metal batteries with this design exhibit low discharge capacity, initial coulombic efficiency, and cycle performance.

[0083] [Metal Battery]

[0084] Based on this, this application provides a metal battery including a positive electrode, a negative electrode and a separator. The separator includes a substrate and at least one adhesive layer disposed on the surface of the substrate. The adhesive layer includes at least a first adhesive layer disposed between the substrate and the negative electrode and / or a second adhesive layer disposed between the substrate and the positive electrode.

[0085] Based on the total mass of the separator membrane, the fluorine content of the first adhesive layer is less than or equal to 500 ppm;

[0086] Based on the total mass of the separator membrane, the fluorine content of the second adhesive layer is less than 1200 ppm.

[0087] Whether the adhesive layer contains fluorine can be measured using methods and equipment known in the art. For example, it can be detected by infrared spectroscopy. Specifically, the battery is disassembled to obtain the separator. After thoroughly washing the separator with a suitable solvent (e.g., DME) and drying it, an infrared beam is passed through the surface of the separator adhesive layer to a depth of a few μm (ATR is Ge crystal), for example, 700 nm. The percentage transmittance versus wavenumber curve of the infrared light is recorded to obtain the infrared spectrum. Functional group analysis is performed based on the infrared spectrum to determine whether the separator adhesive layer contains fluorine. The functional group analysis of the obtained infrared spectrum can be performed with reference to the national standard GB / T6040-2002, General Rules for Infrared Spectroscopy Analysis. When the infrared beam passes through the first adhesive layer, it can be determined whether the first adhesive layer contains fluorine; when the infrared beam passes through the second adhesive layer, it can be determined whether the second adhesive layer contains fluorine.

[0088] The fluorine content of the first adhesive and the fluorine content of the second adhesive layer can be measured using methods and equipment known in the art. For example, it can be measured using inductively coupled plasma (ICP) and energy dispersive spectroscopy (EDS). Specifically, the battery is disassembled to obtain the separator. After thoroughly washing the separator with a suitable solvent (e.g., DME) and drying it, the total fluorine content of the separator is detected by inductively coupled plasma (ICP) testing. Specific methods can be found in YS / T1006.2-2014, GB / T23367.2-2009, or YS / T1028.5-2015. An inductively coupled plasma emission spectrometer (iCAP 740) is used, and the measurement is performed according to the instrument's instruction manual to obtain the total fluorine content W of the separator. F The first adhesive layer of the separator was subjected to elemental analysis (EDS) under a scanning electron microscope (SEM). Referencing GB / T 17359-2012, an area elemental analysis mode was used. The total mass of all elements in the scanned area of ​​the first adhesive layer was obtained, and the mass percentage of fluorine in the scanned area of ​​the first adhesive layer was y1. Using the same method, the total mass of all elements in the scanned area of ​​the second adhesive layer was obtained, and the mass percentage of fluorine in the scanned area of ​​the second adhesive layer was y2. The thickness of the separator substrate was calibrated as d by ion polishing cross-section testing. Based on the material type of the substrate, the true density ρ of the substrate was obtained from publicly available material information. Therefore, the mass of the substrate per unit area was calculated as m0 = d × ρ. The length and width of the separator were measured with calipers, and the area S0 of the substrate was calculated. Thus, the mass of the substrate m` = m0 × S0. The mass of the separator was obtained as m3 by weighing. The mass of the separator is equal to the sum of the mass of the substrate m`, the mass of the first adhesive layer m1, and the mass of the second adhesive layer m2. Let the mass of fluorine in the first adhesive layer be F1 and the mass of fluorine in the second adhesive layer be F2. From the parameters obtained in the above tests, the following relationships can be derived: m1 + m2 = m3 - m`; (F1 + F2) / m3 = W F F1 = y1 × m1; F2 = y2 × m2; From these four equal relationships, we can obtain the mass m1 of the first adhesive layer and the mass m2 of the second adhesive layer, and thus obtain the mass F1 of the fluorine element in the first adhesive layer and the mass F2 of the fluorine element in the second adhesive layer. Based on the total mass of the separator membrane, the fluorine content of the first adhesive layer = F1 / m3; Based on the total mass of the separator membrane, the fluorine content of the second adhesive layer = F2 / m3.

[0089] In some embodiments, the separator includes a substrate and a first adhesive layer disposed between the surface of the substrate and the negative electrode sheet, wherein the fluorine content of the first adhesive layer is less than or equal to 500 ppm, based on the total mass of the separator.

[0090] In some embodiments, the separator includes a substrate and a second adhesive layer disposed between the surface of the substrate and the positive electrode layer, wherein the fluorine content of the second adhesive layer is less than or equal to 1200 ppm, based on the total mass of the separator.

[0091] In some embodiments, the separator includes a substrate, a first adhesive layer disposed between the surface of the substrate and the negative electrode, and a second adhesive layer disposed between the surface of the substrate and the positive electrode; the fluorine content of the first adhesive layer is less than or equal to 500 ppm based on the total mass of the separator; and the fluorine content of the second adhesive layer is less than or equal to 1200 ppm based on the total mass of the separator.

[0092] In some embodiments, the adhesive layer is disposed on the surface of the substrate and is in direct contact with the substrate.

[0093] In some embodiments, the adhesive layer is disposed on the surface of the substrate, and other layers of material may also be disposed between the adhesive layer and the substrate.

[0094] This application does not impose any particular restrictions on the type of substrate for the separator membrane; any known porous substrate with good chemical and mechanical stability can be selected.

[0095] In some embodiments, the substrate may be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The substrate may be a single-layer film or a multi-layer composite film, without particular limitation. When the substrate is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0096] In metal batteries, adhesive layers can be provided on both sides of the separator to stabilize the interface and prevent dendrite puncture. However, metal batteries with this design have low discharge capacity, initial coulombic efficiency, and cycle performance. Furthermore, this application has found that the fluorine-containing groups of the binder in the adhesive layer readily undergo reduction reactions with the metal on the negative electrode. For example, the first adhesive layer directly contacts the deposited metal on the negative electrode, leading to a direct side reaction. Alternatively, the fluorine-containing binder in the second adhesive layer readily dissolves in the electrolyte solvent, allowing it to penetrate the separator and reach the negative electrode side, where it reacts with the deposited metal, resulting in the consumption of metal on the negative electrode and thus reducing the discharge capacity and cycle performance of the metal battery. This application reduces the concentration of fluorine dissolved in the electrolyte solvent by controlling the fluorine content of the second adhesive layer to below 1200 ppm, thereby reducing the degree of side reaction with the deposited metal on the negative electrode; and / or, by controlling the fluorine content of the first adhesive layer to be less than or equal to 500 ppm, reducing the degree of side reaction with the deposited metal on the directly contacting negative electrode. This application improves the discharge capacity, initial coulombic efficiency, and cycle performance of metal batteries by rationally designing the fluorine content of the separator adhesive layer, while also exhibiting good interface stability.

[0097] In some implementations, the fluorine content of the first adhesive layer is equal to 0 ppm, based on the total mass of the separator membrane.

[0098] In some implementations, the fluorine content of the second adhesive layer is less than or equal to 500 ppm, based on the total mass of the separator membrane.

[0099] In some embodiments, the fluorine content of the first adhesive layer can be 500ppm, 450ppm, 400ppm, 350ppm, 300ppm, 250ppm, 200ppm, 150ppm, 100ppm, 50ppm, 0ppm, or a range of any two of the above fluorine contents, or a value within the range, based on the total mass of the separator membrane.

[0100] In some embodiments, the fluorine content of the first adhesive layer can be 1200ppm, 1100ppm, 1000ppm, 900ppm, 800ppm, 700ppm, 600ppm, 500ppm, 400ppm, 300ppm, 200ppm, 100ppm, 50ppm, 0ppm, or a range of any two of the above fluorine contents, or a value within that range, based on the total mass of the separator membrane.

[0101] When the fluorine content of the second binder layer in this application is further reduced, it is beneficial to further reduce the amount of fluorine-containing substances dissolved in the electrolyte solvent, thereby reducing the degree of side reaction with the negative electrode metal and reducing metal loss. When the fluorine content of the first binder layer in this application is 0, it can avoid side reactions with the metal deposited on the negative electrode sheet in direct contact, reducing metal loss. Through the above-mentioned further optimization of the fluorine content, it is helpful to further improve the discharge specific capacity, initial coulombic efficiency and cycle performance of the metal battery in this application.

[0102] In some embodiments, the positive electrode includes a positive electrode film layer, which includes a positive electrode active material. The positive electrode active material includes a metal element. During charging, the positive electrode active material releases metal ions, which are reduced and precipitated as metal on the negative electrode. During discharging, the metal is oxidized and dissolved into metal ions. In some embodiments, the metal element includes sodium. In some embodiments, the metal element includes lithium.

[0103] In some embodiments, the metal ion includes sodium ion. In some embodiments, the metal element includes sodium.

[0104] In some embodiments, the metal ions include lithium ions. In some embodiments, the metal element includes lithium.

[0105] In some implementations, during charging, metal elements are released from the positive electrode active material to form metal ions, which are then reduced and deposited as metal on the negative electrode. During discharging, the metal is oxidized and dissolved into metal ions.

[0106] In some embodiments, the first adhesive layer includes a first adhesive, and the second adhesive layer includes a second adhesive. The first adhesive and the second adhesive each independently include at least one of the following: methyl methacrylate monomer copolymers and / or homopolymers, sugar monomer copolymers and / or homopolymers, acrylic monomer copolymers and / or homopolymers, styrene monomer copolymers and / or homopolymers, butadiene monomer copolymers and / or homopolymers, phenolic monomer copolymers and / or homopolymers, aldehyde monomer copolymers and / or homopolymers, diamine monomer copolymers and / or homopolymers, dianhydride monomer copolymers and / or homopolymers, benzene ring monomer copolymers and / or homopolymers, or derivatives thereof, or modifiers thereof.

[0107] In some embodiments, the first binder and the second binder each independently comprise at least one selected from the following: methyl methacrylate monomer homopolymer, sugar monomer homopolymer, mannuronic acid monomer and guluronic acid monomer copolymer, acrylic acid monomer homopolymer, styrene monomer and butadiene monomer copolymer, vinyl alcohol monomer homopolymer, phenolic monomer and aldehyde monomer copolymer, diamine monomer and dianhydride monomer copolymer, or benzene ring monomer copolymer. In some embodiments, the first binder comprises at least one selected from the following: methyl methacrylate monomer homopolymer, acrylic acid monomer homopolymer, diamine monomer and dianhydride monomer copolymer, or benzene ring monomer copolymer, or derivatives thereof, or modifiers thereof.

[0108] In some embodiments, the first adhesive and the second adhesive each independently comprise at least one of polymethyl methacrylate (PMMA), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), sodium alginate (SA), styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), phenolic resin, polyimide (PI), styrene monomer-butadiene monomer-styrene monomer block copolymer (SBS), or derivatives thereof, or modifiers thereof.

[0109] In some embodiments, the first adhesive and the second adhesive each independently comprise at least one of polymethyl methacrylate, carboxymethyl cellulose, polyacrylic acid, polyimide, styrene monomer-butadiene monomer-styrene monomer block copolymer, or derivatives thereof, or modifiers thereof.

[0110] As used herein, the term "copolymer" refers to a polymer formed by the polymerization of two or more monomers, comprising two or more monomer units. Based on the arrangement of the monomers in the copolymer molecular chain, copolymers can be classified as random copolymers, alternating copolymers, block copolymers, and graft copolymers.

[0111] When used in this document, the term "homogeneous polymer" refers to a polymer formed by the polymerization of a single monomer.

[0112] As used herein, the term "polymer" includes, on the one hand, an aggregate of chemically homogeneous macromolecules prepared by polymerization reactions, but differing in degree of polymerization, molar mass, and chain length. On the other hand, the term also includes derivatives of such aggregates of macromolecules formed by polymerization reactions, i.e., compounds that can be obtained by reactions of the functional groups in the aforementioned macromolecules, such as addition or substitution, and which may be chemically homogeneous or chemically heterogeneous.

[0113] When used in this document, the term "derivative" refers to a substance derived from which a group on the original molecule, such as a hydrogen atom, is replaced by another group.

[0114] When used in this article, the term "modified substance" refers to a substance formed by further modifying the original molecule through various means, such as physical or chemical means, to change a certain physical or chemical property.

[0115] In some embodiments, the weight-average molecular weight of the first adhesive and the second adhesive are each independently between 300,000 and 2,000,000.

[0116] In some embodiments, the weight-average molecular weights of the first and second adhesives can independently be 300,000, 500,000, 700,000, 900,000, 1,000,000, 1,200,000, 1,400,000, 1,600,000, 1,800,000, 2,000,000, or values ​​within the range of the two weight-average molecular weights mentioned above.

[0117] The aforementioned types of binders provide adhesive properties for forming the first and second adhesive layers. Furthermore, the fluorine content of these binders meets the requirements of this application, which is beneficial for further improving the initial coulombic efficiency of the metal battery while maintaining good cycle performance.

[0118] In some embodiments, the first adhesive layer includes a third adhesive; and / or, the second adhesive layer includes a fourth adhesive, wherein the third and fourth adhesives each independently include at least one of a fluorinated monomer copolymer and / or homopolymer, or a derivative thereof, or a modifier thereof.

[0119] In some embodiments, the third and fourth binders each independently comprise at least one of the following: vinylidene fluoride monomer copolymers and / or homopolymers, hexafluoropropylene monomer copolymers and / or homopolymers, vinyl fluoride monomer copolymers and / or homopolymers, trifluoroethylene monomer copolymers and / or homopolymers, perfluoromethyl isopropyl ether monomer homopolymers and / or copolymers, tetrafluoroethylene monomer copolymers and / or homopolymers, vinyl fluoride ester monomer copolymers and / or homopolymers, methyl methacrylate monomer copolymers and / or homopolymers, fluorostyrene monomer copolymers or fluorobenzene monomer copolymers and / or homopolymers, or derivatives thereof, or modifiers thereof.

[0120] In some embodiments, the third and fourth binders each independently comprise at least one of the following: vinylidene fluoride monomer copolymers and / or homopolymers, hexafluoropropylene monomer copolymers, fluoroethylene monomer copolymers, trifluoroethylene monomer copolymers, perfluoromethyl isopropyl ether monomer homopolymers, tetrafluoroethylene monomer copolymers, fluoroethylene ester monomer copolymers, methyl methacrylate monomer copolymers, fluorostyrene monomer copolymers, or fluorobenzene monomer copolymers, or derivatives thereof, or modifiers thereof.

[0121] In some embodiments, the third and fourth adhesives each independently include at least one of vinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trifluoroethylene, polyperfluoromethyl isopropyl ether, polyvinylidene fluoride-tetrafluoroethylene, polyacrylate-fluoroethylene ester, polymethyl methacrylate-fluorostyrene, polystyrene-fluorostyrene, polyester-fluoroethylene ester, polyimide-fluorobenzene, or derivatives thereof, or modifiers thereof.

[0122] In some embodiments, the third binder includes polyvinylidene fluoride (PVDF).

[0123] In some embodiments, the fourth binder includes at least one of polyvinylidene fluoride (PVDF) or polyvinyl fluoride-trifluoroethylene (PVDF-TRFE).

[0124] When the fluorine content design of the first and second adhesive layers of this application is met, the first and / or second adhesive layers may also include a third and / or fourth adhesive agent made of fluorinated copolymers and / or homopolymers. Adding adhesives of the above types to the first and / or second adhesive layers helps to increase the adhesive properties of the adhesive layers.

[0125] In some embodiments, the mass ratio of the first adhesive to the third adhesive is (1-0.5):(0:0.5).

[0126] In some embodiments, the mass ratio of the first adhesive to the third adhesive can be 1:0, 0.9:0.1, 0.8:0.2, 0.7:0.3, 0.6:0.4, 0.5:0.5, or a range of any two of the above mass ratios, or a value within that range.

[0127] In some embodiments, the first adhesive layer comprises only a first adhesive.

[0128] In some embodiments, the first adhesive layer includes a first adhesive and a third adhesive, wherein the mass ratio of the first adhesive to the third adhesive is less than or equal to 0.5:0.5.

[0129] In some embodiments, the mass ratio of the second adhesive to the fourth adhesive is (1-0):(0-1).

[0130] In some embodiments, the mass ratio of the second adhesive to the fourth adhesive can be 1:0, 0.9:0.1, 0.8:0.2, 0.7:0.3, 0.6:0.4, 0.5:0.5, 0.4:0.6, 0.3:0.7, 0.2:0.8, 0.1:0.9, or 0:1.

[0131] In some embodiments, the second adhesive layer comprises only a second adhesive.

[0132] In some embodiments, the second adhesive layer comprises only the fourth adhesive.

[0133] In some embodiments, the second adhesive layer includes a second adhesive layer and a fourth adhesive layer.

[0134] Controlling the mass ratio of the first binder to the third binder in the first adhesive layer within a suitable range, and / or controlling the mass ratio of the second binder to the fourth binder in the second adhesive layer within a suitable range, helps to further balance the bonding performance of the first binder and the second adhesive layer with the discharge capacity, initial coulombic efficiency and cycle performance of the metal battery.

[0135] In some embodiments, the unit area mass of the first adhesive layer is 0-0.3 mg / cm². 2 ; and / or, the unit area mass of the second adhesive layer is 0-0.3 mg / cm³. 2 The unit area mass of the first adhesive layer and the second adhesive layer is not both 0 mg / cm³. 2 .

[0136] In some embodiments, the unit area mass of the first adhesive layer can be 0 mg / cm³. 2 0.02 mg / cm 2 0.05 mg / cm 20.07 mg / cm 2 0.1 mg / cm 2 0.12 mg / cm 2 0.15 mg / cm 2 0.17 mg / cm 2 0.2 mg / cm 2 0.22 mg / cm 2 0.25 mg / cm 2 0.27 mg / cm 2 0.3 mg / cm 2 , or is a range of the unit area mass of any two of the first adhesive layers, or is a value within the range of the composition.

[0137] In some embodiments, the unit area mass of the second adhesive layer can be 0 mg / cm³. 2 0.02 mg / cm 2 0.05 mg / cm 2 0.07 mg / cm 2 0.1 mg / cm 2 0.12 mg / cm 2 0.15 mg / cm 2 0.17 mg / cm 2 0.2 mg / cm 2 0.22 mg / cm 2 0.25 mg / cm 2 0.27 mg / cm 2 0.3 mg / cm 2 , or is a range of the unit area mass of any two of the above second adhesive layers, or is a value within the range of the composition.

[0138] In some embodiments, the thickness of the first adhesive layer is 0-15 μm; and / or the thickness of the second adhesive layer is 0-15 μm, wherein the thicknesses of the first adhesive layer and the second adhesive layer are not both 0 μm.

[0139] In some embodiments, the thickness of the first adhesive layer may be 0 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or a range consisting of any two of the above first adhesive layer thicknesses, or a value within that range.

[0140] In some embodiments, the thickness of the second adhesive layer may be 0 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, or a range consisting of any two of the above-mentioned thicknesses of the second adhesive layer, or a value within that range.

[0141] Controlling the unit area mass of the first adhesive layer and / or the unit area mass of the second adhesive layer within a suitable range helps improve the interfacial adhesion performance, enhances the liquid absorption and retention capacity of the separator, and facilitates the separator to provide a suitable ion transport distance, thereby optimizing the kinetic performance of the metal battery.

[0142] [Negative electrode plate]

[0143] In some implementations, the negative electrode is an inert material that does not participate in the electrochemical reaction.

[0144] In some embodiments, the negative electrode sheet includes a negative current collector and a negative active material disposed on at least one surface of the negative current collector. The negative active material includes at least one of lithium, sodium, zinc, iron, chromium, manganese, tin, aluminum, copper, nickel, or their alloys or oxides.

[0145] When used in this document, the term "alloy" refers to a solid product with metallic properties obtained by mixing and melting one metal with one or more other metals or non-metals, and then cooling and solidifying it.

[0146] As used herein, the term "oxide" refers to a compound composed of two elements, one of which is oxygen. Specifically, when the other element is a metal, the resulting oxide is a metal oxide.

[0147] When used in this document, the term "non-anode negative electrode sheet" refers to a negative electrode sheet in which no active material layer has been deposited beforehand, and a deposited metal layer is formed on the negative electrode surface during the first operation.

[0148] Compared to metal anodes, anode-less anode plates do not contain anode active materials. Electron transfer is accomplished solely by the reduction and deposition of metal ions from the cathode active material on the current collector surface. Therefore, the consumption of metal deposited on the anode plate in anode-less metal battery has a greater impact on the battery's discharge specific capacity and initial coulombic efficiency. When the anode plate of the metal battery in this application is an inert material that does not participate in the electrochemical reaction, i.e., anode-less anode plate, the fluorine content design of the adhesive layer in the separator in this application helps to better improve the discharge specific capacity and initial coulombic efficiency of the metal battery.

[0149] In some embodiments, the negative electrode includes a porous layer formed on the surface of the negative electrode, the porous layer having micron, submicron or nano-sized pores.

[0150] When used in this article, the term "micrometer scale" refers to pores with an average diameter of 1-999 micrometers.

[0151] As used herein, the term "submicron" refers to pores with an average diameter of 0.1–1 micrometer. In some specific embodiments, the ranges of submicron and nanometer overlap and should be understood as appropriate.

[0152] As used herein, the term "nanoscale" refers to pores with an average diameter of 1-999 nanometers. In some specific embodiments, the nanometer and submicron ranges overlap and should be understood as appropriate.

[0153] In some implementations, the thickness of the porous layer is 0.05-1 mm.

[0154] In some embodiments, the thickness of the porous layer can be 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, 1 mm, or a value within the range of any two of the above porous layer thicknesses.

[0155] In some embodiments, micron or submicron pores account for 50-95% of the volume of the porous layer. In some embodiments, micron or submicron pores account for 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the volume of the porous layer, or a value within a range consisting of any two of the above percentages.

[0156] In some embodiments, nanoscale pores account for 10%-99% of the volume of the porous layer. In some embodiments, nanoscale pores account for 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% of the volume of the porous layer, or a value within a range consisting of any two of the above percentages.

[0157] The porous layer has a large specific surface area, which is beneficial for providing a larger deposition specific surface area for metal ions released from the positive electrode active material. This results in more uniform precipitation of metal ions on the negative electrode sheet, effectively reducing the formation of dendrites in the negative electrode. In addition, the porous layer also helps to shorten the migration distance of metal ions during charging and discharging, which helps to reduce diffusion resistance problems during the reaction.

[0158] In some implementations, the porous layer comprises a carbon-based material.

[0159] In any embodiment, the carbon-based material includes at least one of carbon black, activated carbon, carbon nanotubes, carbon fibers, or graphite.

[0160] In some embodiments, the carbon-based material includes activated carbon. In some embodiments, the activated carbon includes activated carbon felt or activated carbon fiber cloth.

[0161] In some embodiments, the carbon-based material includes carbon black. In some embodiments, the carbon black includes Ketjen black.

[0162] When the porous layer includes carbon-based materials, the negative electrode exhibits superior electronic conductivity. Furthermore, the surface of carbon-based materials typically possesses functional groups such as -COOH and -OH, which have a better affinity for metals, especially sodium, allowing for the control of the formation of superior deposition morphology. In addition, when selecting carbon-based materials, activated carbon has a porous structure and a large specific surface area, while being relatively inexpensive; Ketjen black has a large specific surface area and good adsorption capacity, which helps to ensure more uniform precipitation of metal ions on the negative electrode.

[0163] In some implementations, the negative electrode current collector includes a metal current collector, a carbon-based material current collector, a stainless steel current collector, or a composite current collector.

[0164] In some embodiments, the metal current collector includes at least one of copper, aluminum, aluminum alloy, iron, iron alloy, tin, tin alloy, zinc, zinc alloy, nickel, nickel alloy, manganese, manganese alloy, lead, lead alloy, antimony, antimony alloy, cadmium, cadmium alloy, bismuth, and bismuth alloy.

[0165] In some embodiments, the carbon-based material in the carbon-based current collector includes graphite material.

[0166] In some embodiments, the composite current collector includes a polymeric material substrate and a metal layer formed on at least one surface of the polymeric material substrate. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymeric material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0167] In some embodiments, the positive electrode film layer includes a positive electrode film layer binder, and the fluorine content of the positive electrode sheet is less than or equal to 385 ppm, based on the total mass of the positive electrode film layer.

[0168] Metal batteries include an electrolyte. The difference between the lowest unoccupied molecular orbital energy level LUMO2 of the electrolyte solvent and the lowest unoccupied molecular orbital energy level LUMO1 of the metallic state corresponding to the metal element in the positive electrode active material is y = LUMO2 energy level - LUMO1 energy level, 0 ≤ y.

[0169] In some embodiments, the metallic state of a metal element refers to its elemental form with a oxidation state of 0. In some specific embodiments, the metallic state of sodium refers to elemental sodium, and the metallic state of lithium refers to elemental lithium.

[0170] When used in this article, the term "lowest unoccupied molecular orbital level" or "LUMO level" refers to the energy level of the molecular orbital with the lowest energy. The LUMO level is numerically equivalent to the electron affinity of a molecule. The lower the LUMO level, the easier it is for the substance to gain electrons. It can be used to determine the reduction resistance of a substance; the lower the energy level, the easier it is to be reduced.

[0171] The lowest unoccupied molecular orbital energy level of the material can be obtained using methods known in the art, for example, by referring to Diphenyl Ketone towards Ultra-stable Hard Carbon Anodes for Sodium-Ion Batteries (Angewandte Chemie, 2022. DOI:10.1002 / anie.202214717), calculated according to first-principles theory, specifically using density functional theory (DFT). As an example, the theoretical calculations were performed using Gaussian 09 software with a Becke three-parameter Li-Yang-Pahr (B3LYP) mixed functional. No symmetry constraints were imposed during the structure optimization process to obtain accurate geometry. The energy and force convergence thresholds were set at [values ​​missing] per atom. and Furthermore, atomic properties are represented by the 6-311+G(d) basis set. Dispersion-corrected density functional theory (DFT-D2) calculations were performed using the Vienna Ab initio Simulation Package (VASP), employing the generalized gradient approximation (GGA) and the Perdew-Burke-Eznerhof (PBE) functional (GGA-PBE) to describe the exchange-related energies of electrons. The projection-enhanced wave method (PAW) was used to handle the nucleus-electron interactions. The k-point on the Brillouin zone was 5×5×1, with an energy cutoff of 400 eV. Atomic positions and cell vectors were fully optimized until all force components were less than 1. The LUMO energy level of the material can be obtained by using the simulation calculation method described above.

[0172] During charging and discharging, the extraction of metal ions from the positive electrode active material, their reduction precipitation on the negative electrode, and the oxidative dissolution process can be detected using methods and equipment known in the art. For example, X-ray photoelectron spectroscopy (XPS) can be used for testing. Specifically, XPS is used to detect unformed negative electrodes and fully charged negative electrodes with coatings, and valence state analysis of metal elements, such as sodium, can identify the ionic and metallic states of the metal elements, thereby determining whether a redox reaction has occurred.

[0173] The test for whether the positive electrode sheet contains fluorine can be performed using the same method as the test for whether the adhesive layer contains fluorine.

[0174] The fluorine content of the positive electrode can be measured using methods and equipment known in the art. For example, it can be tested using inductively coupled plasma (ICP). As an example, the fluorine content of the positive electrode can be obtained by using an inductively coupled plasma emission spectrometer (iCAP 740) according to the instrument's instruction manual, as specified in YS / T1006.2-2014, GB / T23367.2-2009, or YS / T1028.5-2015.

[0175] The electrolyte solvent and the metallic state corresponding to the metal element in the positive electrode active material have a suitable LUMO energy level relationship, which helps to reduce the degree of side reactions with the negative electrode metal, thus making it more compatible with the negative electrode and improving the electrical performance of the metal battery. Furthermore, by controlling the fluorine content of the positive electrode sheet to be less than or equal to 385 ppm, this application helps to further reduce the concentration of fluorine-containing substances dissolved in the positive electrode sheet in the electrolyte solvent, thereby reducing the degree of side reactions with the negative electrode metal, further reducing metal consumption, and further improving the discharge capacity, initial coulombic efficiency, and cycle performance of the metal battery.

[0176] In some implementations, the fluorine content of the positive electrode sheet is less than or equal to 120 ppm, based on the total mass of the positive electrode film.

[0177] In some embodiments, the fluorine content of the positive electrode sheet can be 385ppm, 375ppm, 365ppm, 355ppm, 345ppm, 335ppm, 325ppm, 315ppm, 300ppm, 285ppm, 265ppm, 245ppm, 225ppm, 205ppm, 185ppm, 165ppm, 145ppm, 125ppm, 120ppm, 105ppm, 85ppm, 65ppm, 45ppm, 25ppm, 15ppm, or 0ppm, or a value within any two of the above fluorine content ranges, using the total mass of the positive electrode film as the calculation basis.

[0178] When the fluorine content of the positive electrode sheet of this application is further reduced, it is beneficial to further reduce the fluorine-containing substances dissolved in the electrolyte solvent, thereby reducing the side reaction with the negative electrode metal, reducing metal loss, and further improving the discharge specific capacity, initial coulombic efficiency and cycle performance of the metal battery of this application.

[0179] In some implementations, 0.7 ≤ y.

[0180] In some implementations, 0.1≤y, 0.2≤y, 0.3≤y, 0.4≤y, 0.5≤y, 0.6≤y, or 0.7≤y.

[0181] Further control over the relationship between the metal state corresponding to the metal element in the positive electrode active material and the lowest unoccupied molecular orbital energy level difference of the electrolyte solvent is beneficial to further improve the compatibility between the electrolyte and the negative electrode, and improve the discharge specific capacity and initial coulombic efficiency of the metal battery of this application.

[0182] In some embodiments, the positive electrode film binder includes a fifth binder, which is a copolymer and / or homopolymer, wherein the monomers of the copolymer and homopolymer have 2 or fewer fluorine-containing substituents.

[0183] In some embodiments, the fifth binder is a copolymer in which the number of fluorine-containing substituents in the monomer of the copolymer is less than or equal to 2.

[0184] In some embodiments, the fluorine-containing substituents in the monomers of the copolymer can be 2, 1, or 0.

[0185] In some embodiments, the fifth binder is a homopolymer in which the monomers of the homopolymer contain 2 or fewer fluorine-containing substituents.

[0186] In some embodiments, the fluorine-containing substituents in the monomer of the homopolymer can be 2, 1, or 0.

[0187] In the positive electrode of this application, the fluorine-containing substances that are easily soluble in the electrolyte solvent are mainly the binder. Controlling the number of fluorine-containing substituents in the fifth binder helps to balance the binding performance of the fifth binder and reduce the amount of fluorine-containing groups dissolved in the electrolyte solvent, thereby helping to further reduce the side reactions between the fluorine-containing groups and the negative electrode metal, reduce metal loss, and further improve the discharge specific capacity, initial coulombic efficiency, and cycle performance of the metal battery of this application.

[0188] In some embodiments, the fifth binder comprises at least one of methyl methacrylate monomer copolymers and / or homopolymers, sugar monomer copolymers and / or homopolymers, acrylic monomer copolymers and / or homopolymers, styrene monomer copolymers and / or homopolymers, butadiene monomer copolymers and / or homopolymers, phenolic monomer copolymers and / or homopolymers, aldehyde monomer copolymers and / or homopolymers, diamine monomer copolymers and / or homopolymers, dianhydride monomer copolymers and / or homopolymers, benzene ring monomer copolymers and / or homopolymers, or derivatives thereof, or modifiers thereof.

[0189] In some embodiments, the fifth binder comprises at least one selected from methyl methacrylate monomer homopolymer, sugar monomer homopolymer, mannuronic acid monomer and guluronic acid monomer copolymer, acrylic acid monomer homopolymer, styrene monomer and butadiene monomer copolymer, vinyl alcohol monomer homopolymer, phenolic monomer and aldehyde monomer copolymer, diamine monomer and dianhydride monomer copolymer, or benzene ring monomer copolymer. In some embodiments, the first binder comprises at least one selected from methyl methacrylate monomer homopolymer, acrylic acid monomer homopolymer, diamine monomer and dianhydride monomer copolymer, or benzene ring monomer copolymer, or derivatives thereof, or modifiers thereof.

[0190] In some embodiments, the fifth binder includes at least one of polymethyl methacrylate (PMMA), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), sodium alginate (SA), styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), phenolic resin, polyimide (PI), styrene monomer-butadiene monomer-styrene monomer block copolymer (SBS), or derivatives thereof, or modifiers thereof.

[0191] In some embodiments, the fifth binder includes at least one of carboxymethyl cellulose, polyacrylic acid, polyimide, styrene monomer-butadiene monomer-styrene monomer block copolymer, or derivatives thereof, or modifiers thereof.

[0192] When the positive electrode film binder includes the aforementioned fifth binder, it provides better adhesion performance for forming the positive electrode film. Simultaneously, the fluorine content of the aforementioned fifth binder meets the requirements of this application; specifically, when the positive electrode film includes the aforementioned fifth binder, the fluorine content of the positive electrode sheet meets the requirements of this application. The application of the aforementioned fifth binder in the positive electrode film of this application helps to further reduce the amount of fluorine-containing groups in the electrolyte, thereby helping to further reduce the side reactions between fluorine-containing groups and the negative electrode metal, reducing metal loss, and further improving the initial coulombic efficiency and cycle performance of the metal battery of this application.

[0193] In some embodiments, the positive electrode film layer binder includes a sixth binder, which includes fluorinated monomer copolymers and / or homopolymers, or derivatives thereof, or modifications thereof.

[0194] In some embodiments, the sixth binder includes at least one of the following: vinylidene fluoride monomer copolymers and / or homopolymers, hexafluoropropylene monomer copolymers and / or homopolymers, vinyl fluoride monomer copolymers and / or homopolymers, trifluoroethylene monomer copolymers and / or homopolymers, perfluoromethyl isopropyl ether monomer homopolymers and / or copolymers, tetrafluoroethylene monomer copolymers and / or homopolymers, vinyl fluoride ester monomer copolymers and / or homopolymers, methyl methacrylate monomer copolymers and / or homopolymers, fluorostyrene monomer copolymers or fluorobenzene monomer copolymers and / or homopolymers, or derivatives thereof, or modifiers thereof.

[0195] In some embodiments, the sixth binder includes at least one of vinylidene fluoride monomer copolymers and / or homopolymers, hexafluoropropylene monomer copolymers, fluoroethylene monomer copolymers, trifluoroethylene monomer copolymers, perfluoromethyl isopropyl ether monomer homopolymers, tetrafluoroethylene monomer copolymers, fluoroethylene ester monomer copolymers, methyl methacrylate monomer copolymers, fluorostyrene monomer copolymers, or fluorobenzene monomer copolymers, or derivatives thereof, or modifiers thereof.

[0196] In some embodiments, the sixth binder includes at least one selected from vinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trifluoroethylene, polyperfluoromethyl isopropyl ether, polyvinylidene fluoride-tetrafluoroethylene, polyacrylate-fluorovinyl ester, polymethyl methacrylate-fluorostyrene, polystyrene-fluorostyrene, polyester-fluorovinyl ester, polyimide-fluorobenzene, or derivatives thereof, or modifiers thereof. In some embodiments, the sixth binder includes polyvinylidene fluoride (PVDF).

[0197] When the fluorine content of the positive electrode sheet in this application is less than or equal to 385 ppm, the positive electrode film binder in this application may also include a sixth binder of fluorinated copolymers and / or homopolymers. Adding a sixth binder of the above type to the positive electrode film binder helps to increase the adhesion performance of the positive electrode film binder.

[0198] In some embodiments, the mass ratio of the fifth adhesive to the sixth adhesive is (1-0.5):(0-0.5).

[0199] In some embodiments, the mass ratio of the fifth adhesive to the sixth adhesive can be 1:0, 0.9:0.1, 0.8:0.2, 0.7:0.3, 0.6:0.4, or 0.5:0.5.

[0200] Controlling the fifth and sixth binders within a suitable range helps to further balance the bonding performance of the positive electrode film binder and the discharge specific capacity, initial coulombic efficiency, and cycle performance of the metal battery of this application.

[0201] In some embodiments, the mass percentage of the positive electrode film binder is less than or equal to 3% and greater than or equal to 0.5% based on the total mass of the positive electrode film.

[0202] In some embodiments, the mass percentage of the positive electrode film binder, based on the total mass of the positive electrode film, can be 3%, 2.5%, 2%, 1.5%, 1%, 0.5%, or a value within the range of any two of the above mass percentages.

[0203] In some embodiments, when the mass ratio of the fifth binder to the sixth binder is greater than or equal to 0.5:0.5 and less than 0.6:0.4, the mass percentage of the binder in the positive electrode film layer is less than or equal to 2% and greater than or equal to 0.5% based on the total mass of the positive electrode film layer.

[0204] In some embodiments, when the mass ratio of the fifth binder to the sixth binder is greater than or equal to 0.6:0.4 and less than 0.7:0.3, the mass percentage of the positive electrode film layer binder is less than or equal to 2.5% and greater than or equal to 0.5% based on the total mass of the positive electrode film layer.

[0205] In some embodiments, when the mass ratio of the fifth binder to the sixth binder is (1-0.7):(0-0.3), the mass percentage content of the positive electrode film binder is less than or equal to 3% and greater than or equal to 0.5%.

[0206] Controlling the binder content in the positive electrode film within a suitable range helps to provide appropriate bonding performance while reducing the fluorine content of the positive electrode sheet. This helps to further reduce the capacity degradation of the metal battery in this application and improve its initial coulombic efficiency and cycle capacity.

[0207] Electrolyte

[0208] In some embodiments, the electrolyte comprises a solvent and a sodium salt dissolved in the solvent, wherein the solvent comprises at least one ether compound of formula I, R1-(O-R3). n -O-R2 (I)

[0209] R1 and R2 are each independently selected from C1-C6 alkyl groups, R3 is selected from C1-C6 alkylene groups, and n is selected from integers from 1 to 5.

[0210] As used herein, the term "C1-C6 alkyl" refers to a straight-chain or branched hydrocarbon chain group consisting only of carbon and hydrogen atoms, without unsaturation, having one to six carbon atoms, and connected to the rest of the molecule by single bonds. The terms "C1-C5 alkyl," "C1-C4 alkyl," "C1-C3 alkyl," and "C1-C2 alkyl" should be interpreted accordingly. Examples of C1-C6 alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, 1-methylethyl (isopropyl), n-butyl, n-pentyl, or 1,1-dimethylethyl (tert-butyl).

[0211] As used herein, the term "C1-C6 alkylene" refers to a C1-C6 divalent alkyl group. Any alkyl group can form an alkylene group by losing a hydrogen atom to create a half-bond. The terms "C1-C5 alkylene," "C1-C4 alkylene," "C1-C3 alkylene," and "C1-C2 alkylene" should be interpreted accordingly. Examples of C1-C6 alkylene groups include, but are not limited to: -CH2-, -CH(CH3)-, -C(CH3)2-, -CH2CH2-, -CH2-CH(CH3)-, -CH2C(CH3)2-, -CH2CH2CH2-, and -CH2CH2CH2CH2-.

[0212] In some embodiments, R1 and R2 are each independently selected from C6 alkyl, C5 alkyl, C4 alkyl, C3 alkyl, ethyl, or methyl. In some embodiments, R1 and R2 are each independently selected from methyl, ethyl, n-propyl, isopropyl, 1-methylethyl (isopropyl), n-butyl, n-pentyl, or 1,1-dimethylethyl (tert-butyl). In some embodiments, R1 and R2 are each independently selected from methyl or ethyl.

[0213] In some embodiments, R3 is selected from C6 alkylene, C5 alkylene, C4 alkylene, C3 alkylene, ethylene, or methylene. In some embodiments, R3 is selected from -CH2-, -CH(CH3)-, -C(CH3)2-, -CH2CH2-, -CH2-CH(CH3)-, -CH2C(CH3)2-, -CH2CH2CH2-, and -CH2CH2CH2CH2-.

[0214] In some embodiments, R3 is selected from straight-chain C1-C5 alkylene groups. In some embodiments, R3 is selected from straight-chain C6 alkylene groups, straight-chain C5 alkylene groups, straight-chain C4 alkylene groups, straight-chain C3 alkylene groups, straight-chain C2 alkylene groups, or straight-chain C1 alkylene groups.

[0215] In some implementations, n is selected from 1, 2, 3, 4 or 5.

[0216] Unlike conventionally used ester-based electrolyte solvents, the electrolyte solvents of the above general formula meet the LUOM energy level requirements of this application and have good compatibility with the negative electrode sheet of this application.

[0217] In some embodiments, R1 and R2 are each independently selected from methyl or ethyl, and R3 is selected from straight-chain C1-C5 alkylene groups.

[0218] In some implementations, R3 is selected from -CH2CH2-.

[0219] When the electrolyte of the metal battery of this application contains the above-mentioned solvent, the secondary battery of this application has a more stable electrolyte window.

[0220] In some embodiments, the solvent includes at least one of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, pentaethylene glycol diethyl ether, or ethylene glycol dibutyl ether.

[0221] When the electrolyte of the metal battery of this application contains the above-mentioned solvent, the electrolyte of this application has better reduction stability and better interface compatibility with the negative electrode of the metal battery, especially sodium metal battery.

[0222] In some embodiments, the sodium salt includes at least one of NaPF6, NaFSI, NaTFSI, NaBF4, NaClO4, or NaOTf.

[0223] 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.

[0224] In some implementations, the metal battery includes a sodium metal battery.

[0225] When used in this document, the term "sodium metal battery" refers to a metal battery that uses sodium ions as charge carriers.

[0226] In some implementations, the metal battery includes a lithium metal battery.

[0227] When used in this document, the term "lithium metal battery" refers to a metal battery that uses lithium ions as charge carriers.

[0228] Through research, this application found that fluorine-containing groups have a stronger reactivity with sodium-deposited metal. Therefore, the fluorine-containing groups in the first adhesive layer of the separator, the fluorine-containing groups in the second adhesive layer dissolved in the electrolyte solvent, and / or the fluorine-containing groups in the positive electrode film binder cause more severe consumption of sodium-deposited metal on the negative electrode. Therefore, when the metal battery of this application is a sodium metal battery, the design of the fluorine content in the adhesive layer of the separator and / or the fluorine content in the positive electrode helps to better improve its discharge capacity, initial coulombic efficiency, and cycle performance.

[0229] [Positive electrode active material]

[0230] In some embodiments, the positive electrode active material includes at least one of polyanionic compounds, layered oxides, Prussian blue compounds, or modified compounds thereof.

[0231] In some implementations, the positive electrode active material may be used alone or in combination of two or more.

[0232] In some embodiments, the combination can be used to mix two or more positive electrode active materials to form a single positive electrode film, or the two or more positive electrode active materials can be used to form two or more positive electrode film layers respectively.

[0233] In some embodiments, the positive electrode active material includes Na a1 Ni b1 Fe c1 Mn d1 M1 e1 O f1 Na x1 M2 y1 M3 y2 (X a2 O b2 ) z1 Z w1 Prussian blue, Prussian white, or at least one of their modified compounds, wherein,

[0234] M includes at least one of active and / or inert doped metal elements, 0.85≤a1≤1, 0≤b1≤1, 0≤c1≤1, 0≤d1≤1, 0≤e1≤1, 1.8≤f1≤2, where b1, c1, d1 and e1 are not simultaneously 0;

[0235] M2 includes at least one of Ti, V, Cr, Mn, Fe, Ca, Mg, Al, Nb, Co, and Zr; M3 includes Ni; X includes at least one of Si, S, P, As, B, Mo, W, and Ge; Z includes at least one of F, O, and OH; 1≤x1≤7, 1≤y1≤4, 0≤y2≤0.05, 0.2≤a2 / b2≤0.3, 1≤z1≤4, and 0≤w1≤7.

[0236] In some implementations, x1 can be 1, 2, 3, 4, 5, 6, 7, or a value within a range formed by any two of the above x1.

[0237] In some implementations, y1 can be 1, 1.5, 2, 2.5, 3, 3.5, 4, or a value within the range of any two y1 values ​​mentioned above.

[0238] In some implementations, y2 can be 0, 0.01, 0.02, 0.03, 0.04, 0.05, or a value within the range of any two y2 values ​​mentioned above.

[0239] In some implementations, a2 / b2 can be 0.2, 0.22, 0.24, 0.25, 0.26, 0.28, 0.3, or a value within the range of any two a2 / b2 values ​​mentioned above.

[0240] In some implementations, z1 can be 1, 1.5, 2, 2.5, 3, 3.5, 4, or a value within the range of any two z1 values.

[0241] In some implementations, w1 can be 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, or a value within the range of any two w1 values ​​mentioned above.

[0242] In some embodiments, the polyanionic compound includes at least one of Na8Fe4(P2O7)5, NaFePO4, NaMnPO4, NaCoPO4, Na4Fe3(PO4)2O7, Na3V2(PO4)2F3, Na3V2(PO4)3, or modified compounds thereof.

[0243] In some embodiments, the layered oxide comprises a layered transition metal oxide. In some embodiments, the layered oxide comprises Na. a1 Ni b1 Fe c1 Mn d1 M1 e1 O f1or at least one of its modified compounds, wherein M includes at least one of active and / or inert doped metal elements, 0.85≤a1≤1, 0≤b1≤1, 0≤c1≤1, 0≤d1≤1, 0≤e1≤1, 1.8≤f1≤2, and b1, c1, d1 and e1 are not simultaneously 0.

[0244] In some embodiments, the active and / or inert doped metal element includes at least one of Co, Zn, V, Cr, Al, Sc, Sn, Sb, Zr, Nb, Ti, Mg, Cu, Ru, Ir, or Ca.

[0245] In some implementations, a1 can be 0.85, 0.87, 0.9, 0.93, 0.96, 0.99, 1, or a value within the range of any two a1 values ​​mentioned above.

[0246] In some implementations, b1 can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or a value within the range of any two b1 values ​​mentioned above.

[0247] In some implementations, c1 can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or a value within the range of any two c1 values ​​mentioned above.

[0248] In some implementations, d1 can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or a value within the range of any two d1 values ​​mentioned above.

[0249] In some implementations, e1 can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or a value within the range of any two e1 values ​​mentioned above.

[0250] In some implementations, f1 can be 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or a value within the range of any two f1 values ​​mentioned above.

[0251] In some embodiments, the positive electrode active material includes Na a1 Ni b1 Fe c1 Mn d1 M1 e1 O f1or at least one of its modified compounds, wherein M includes at least one of active and / or inert doped metal elements, 0.85≤a1≤1, 0≤b1≤0.3, 0≤c1≤0.4, 0≤d1≤0.4, 0≤e1≤0.1, 1.8≤f1≤2, and b1, c1, d1 and e1 are not simultaneously 0.

[0252] In some embodiments, the layered oxide includes at least one of NaFeO2, NaCoO2, NaCrO2, NaMnO2, or NaNiO2.

[0253] In some embodiments, the positive electrode active material includes at least one of olivine-structured lithium phosphates, lithium transition metal oxides, and their modified compounds.

[0254] In some embodiments, the lithium transition metal oxide includes lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ) or lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2).

[0255] In some embodiments, the olivine-structured lithium phosphate includes at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, or lithium manganese iron phosphate and carbon composites.

[0256] [Positive electrode plate]

[0257] In some embodiments, the positive electrode includes a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector, the positive electrode film layer further including a conductive agent.

[0258] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0259] In some embodiments, the positive current collector can be a conductive carbon sheet, a metal foil, a carbon-coated metal foil, a porous metal plate, or a composite current collector. The conductive carbon material of the conductive carbon sheet can be selected from one or more of Super P, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphite, graphene, and carbon nanofibers. The metal material of the metal foil, carbon-coated metal foil, and porous metal plate is independently selected from at least one of copper, aluminum, nickel, and stainless steel. The composite current collector can be a composite current collector formed by combining a metal foil with a polymer base film.

[0260] In some embodiments, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0261] In some embodiments, the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, additives, conductive agents, binders and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry; coating the positive electrode slurry onto a positive current collector, and then obtaining the positive electrode sheet after drying, cold pressing and other processes.

[0262] This application also provides a method for preparing the metal battery of this application.

[0263] In some implementation methods, the method includes the following steps: providing a positive electrode, a negative electrode, and a separator, and preparing a metal battery by winding or stacking the positive electrode, negative electrode, and separator.

[0264] This application does not impose any particular limitation on the shape of the metal battery; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 1 shows a square-structured metal battery 5 as an example.

[0265] In some embodiments, referring to FIG2, the outer packaging may include a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 can be placed over the opening to close the receiving cavity. A positive electrode, a negative electrode, and a separator can be formed into an electrode assembly 52 by a winding process or a stacking process. The electrode assembly 52 is encapsulated within the receiving cavity. Electrolyte is immersed in the electrode assembly 52. ​​The metal battery 5 may contain one or more electrode assemblies 52, which can be selected by those skilled in the art according to specific practical needs.

[0266] In some implementations, metal batteries can be assembled into battery modules, and the number of metal batteries contained in a battery module can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery module.

[0267] Figure 3 shows a battery module 4 as an example. Referring to Figure 3, in the battery module 4, multiple metal batteries 5 can be arranged sequentially along the length of the battery module 4. Of course, they can also be arranged in any other arbitrary way. Furthermore, the multiple metal batteries 5 can be fixed in place by fasteners.

[0268] Optionally, the battery module 4 may also include a housing with a receiving space in which a plurality of metal batteries 5 are received.

[0269] In some embodiments, the battery modules described above can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, the specific number of which can be selected by those skilled in the art according to the application and capacity of the battery pack.

[0270] Figures 4 and 5 show a battery pack 1 as an example. Referring to Figures 4 and 5, the battery pack 1 may include a battery box and multiple battery modules 4 disposed within the battery box. The battery box includes an upper box 2 and a lower box 3, with the upper box 2 covering the lower box 3 to form a closed space for accommodating the battery modules 4. The multiple battery modules 4 can be arranged in any manner within the battery box.

[0271] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0272] In some embodiments, the metal battery may include an outer packaging. This outer packaging may be used to encapsulate the electrode assembly and electrolyte described above.

[0273] In some embodiments, the outer packaging of a metal battery can be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of a metal battery can also be a soft pack, such as a pouch. The material of the soft pack can be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0274] [Electrical appliances]

[0275] This application also provides an electrical device, which includes the metal battery of this application or a metal battery prepared according to the method of this application.

[0276] In some embodiments, the electrical device of this application may further include at least one of a battery module or a battery pack. A secondary battery, battery module, or battery pack can be used as the power source for the electrical device or as the energy storage unit of the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0277] As an electrical device, a secondary battery, battery module, or battery pack can be selected according to its usage requirements.

[0278] Figure 6 shows an example of an electrical device. This device 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 device, a battery pack or battery module can be used.

[0279] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use a rechargeable battery as their power source.

[0280] Example

[0281] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0282] I. Preparation Method

[0283] Example 1

[0284] 1) Preparation of positive electrode sheet

[0285] Sodium iron pyrophosphate (Positive Electrode Active Material), Carbon Black (Super P) (Conductive Agent), and Polyacrylic Acid (PAA) (Binder) were thoroughly mixed in N-methylpyrrolidone at a mass ratio of 96:3:3 to form a uniform positive electrode slurry. The positive electrode slurry was then coated onto the surface of the aluminum foil used as the positive electrode current collector, with a coating weight of 20 mg / cm³. 2 After drying, cold pressing, and slitting, the positive electrode sheet is obtained.

[0286] 2) Preparation of negative electrode sheet

[0287] Carbon nanotubes (CNTs) and sodium carboxymethyl cellulose were thoroughly mixed in deionized water at a weight ratio of 50:50 to form a porous slurry. This porous slurry was then coated onto the surface of a copper foil used as the negative electrode current collector, with a coating thickness of 5 μm. After coating, the material was dried, cold-pressed, and slit to obtain the negative electrode sheet.

[0288] 3) Preparation of electrolyte

[0289] In an argon atmosphere glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), sodium hexafluorophosphate (NaPF6) was dissolved in dimethyl ethylene glycol (DME) and stirred until homogeneous to obtain an electrolyte with a sodium salt concentration of 1 mol / L.

[0290] 4) Preparation of the separating membrane

[0291] Porous polyethylene film is provided as the substrate for the separator membrane;

[0292] Preparation of adhesive layer slurry: PMMA is mixed with water solvent to prepare a first adhesive layer slurry and a second adhesive layer slurry with a solid content of 10%;

[0293] The adhesive slurry is applied to both sides of the substrate, with the first adhesive layer facing the negative electrode having a unit area mass of 0.05 mg / cm². 2 The second adhesive layer facing the positive electrode has a unit area mass of 0.05 mg / cm³. 2 After coating, the release film is dried.

[0294] 5) Battery manufacturing

[0295] The above-mentioned positive electrode, separator, and negative electrode are stacked in sequence to form a button cell, thus obtaining the sodium metal battery without a negative electrode of Example 1.

[0296] The metal battery of Example 2 is prepared in a similar manner to that of Example 1, but the separator does not have a second adhesive layer.

[0297] The metal battery of Example 3 was prepared in a similar manner to that of Example 1, but the separator did not have a first adhesive layer.

[0298] The metal batteries of Examples 4-6 were prepared in a similar manner to those of Example 1, but the type of the first binder was adjusted, as shown in Table 1.

[0299] The metal batteries of Examples 7-9 were prepared in a similar manner to those of Example 1, but the type of adhesive for the second adhesive layer was adjusted, as shown in Table 1.

[0300] The metal battery of Example 10 is prepared in a similar way to that of Example 1, but the type of negative electrode in the positive electrode film is adjusted. That is, the negative electrode sheet is replaced with a sodium metal sheet, which is placed on a stainless steel pad as the negative electrode when assembling the battery. Otherwise, it is the same as the metal battery without a negative electrode.

[0301] The metal batteries of Examples 11-15 are prepared in a similar manner to those of Example 1, but the type and / or amount of positive electrode film binder are adjusted, as shown in Table 1.

[0302] The metal battery of Example 16 was prepared in a similar manner to that of Example 1, but the type of solvent in the electrolyte was adjusted, as shown in Table 2.

[0303] The metal battery of Example 17 was prepared in a similar manner to that of Example 1, but the type of porous layer of the negative electrode was changed to conductive carbon black (SP), as shown in Table 2.

[0304] The metal battery of Comparative Example 1 was prepared in a similar manner to that of Example 1, but the types of binders for the first adhesive layer, the second adhesive layer, and the positive electrode film layer were adjusted to PVDF. The type of electrolyte was also adjusted. Other parameters are shown in Tables 1-2.

[0305] The metal battery of Comparative Example 2 was prepared in a similar manner to that of Example 1, but the types of binders for the first adhesive layer, the second adhesive layer, and the positive electrode film layer were adjusted to PVDF. Other parameters are shown in Tables 1-2.

[0306] The metal battery of Comparative Example 3 is prepared in a similar manner to that of Example 1, but it does not have the first adhesive layer binder, the second adhesive layer binder, and the type of positive electrode film binder is changed to PVDF. Other parameters are shown in Tables 1-2.

[0307] II. Performance Testing

[0308] 1. Fluorine content test

[0309] (1) Test method for whether the first adhesive layer and the second adhesive layer contain fluorine.

[0310] The presence of fluorine in the first and second adhesive layers of the separator can be detected using a Fourier transform infrared spectrometer (IS10). The specific procedure is as follows: Disassemble the battery to obtain the separator. Thoroughly wash the separator with DME and dry it. Pass an infrared beam through the surface of the first adhesive layer of the separator to a depth of 700 nm (ATR is Ge crystal). Record the percentage transmittance versus wavenumber curve to obtain the infrared spectrum. Perform functional group analysis based on the infrared spectrum to determine whether the first adhesive layer contains fluorine. The functional group analysis of the obtained infrared spectrum can be performed by referring to the national standard GB / T6040-2002, General Rules for Infrared Spectroscopy Analysis. When the infrared beam passes through the surface of the second adhesive layer of the separator to a depth of 700 nm, the presence of fluorine in the second adhesive layer can be determined.

[0311] (2) Test method for whether the positive electrode contains fluorine.

[0312] The presence of fluorine in the positive electrode can be detected using a Fourier transform infrared spectrometer (IS10). The specific procedure is as follows: disassemble the battery to obtain the positive electrode, thoroughly wash it with DME, and then dry it. Pass an infrared beam through the electrode to a depth of 700 nm (ATR is Ge crystal), and record the percentage transmittance versus wavenumber curve to obtain the infrared spectrum. Functional group analysis is then performed based on the infrared spectrum to determine whether the positive electrode contains fluorine. The functional group analysis of the obtained infrared spectrum can be performed by referring to the national standard GB / T6040-2002, General Rules for Infrared Spectroscopic Analysis.

[0313] (3) Fluorine content test of the first and second adhesive layers

[0314] The battery was disassembled, and the separator was obtained. The separator was thoroughly washed with DME and then dried. The total fluorine content of the separator can be detected by inductively coupled plasma (ICP) testing. Specific standards include YS / T1006.2-2014, GB / T23367.2-2009, or YS / T1028.5-2015. An inductively coupled plasma atomic emission spectrometer (iCAP 740) was used, and the measurement was performed according to the instrument's instruction manual to obtain the total fluorine content W in the separator. F .

[0315] The first adhesive layer of the separator was placed under a scanning electron microscope for elemental analysis (EDS). For details, refer to GB / T 17359-2012. Using the area elemental analysis mode, the total mass of all elements in the scanned area of ​​the first adhesive layer was obtained. The mass percentage of fluorine in the scanned area of ​​the first adhesive layer was y1. Using the same test method, the total mass of all elements in the scanned area of ​​the second adhesive layer was obtained. The mass percentage of fluorine in the scanned area of ​​the second adhesive layer was y2.

[0316] The thickness of the separator substrate is calibrated as d by ion polishing cross-section test. Based on the material type of the substrate, the true density information ρ of the substrate can be obtained by consulting the publicly available material information. From this, the mass of the substrate per unit area can be calculated as m0 = d × ρ. The area S0 of the substrate is calculated by measuring the length and width of the separator with calipers. That is, the mass of the substrate m` = m0 × S0.

[0317] The mass of the release liner was determined by weighing, and the mass of the release liner was m3. The mass of the release liner was equal to the sum of the mass of the substrate m`, the mass of the first adhesive layer m1, and the mass of the second adhesive layer m2.

[0318] Let the mass of fluorine in the first adhesive layer be F1 and the mass of fluorine in the second adhesive layer be F2. From the parameters obtained in the above tests, the following relationships can be derived: m1 + m2 = m3 - m`; (F1 + F2) / m3 = W F ; F1=y1×m1; F2=y2×m2;

[0319] From the above four equal relationships, we can obtain the mass m1 of the first adhesive layer and the mass m2 of the second adhesive layer. From this, we can obtain the mass F1 of the fluorine element in the first adhesive layer and the mass F2 of the fluorine element in the second adhesive layer. Based on the total mass of the separator membrane, the fluorine content of the first adhesive layer is F1 / m3; and based on the total mass of the separator membrane, the fluorine content of the second adhesive layer is F2 / m3.

[0320] (4) Fluorine content test of positive electrode sheet

[0321] The fluorine content of the positive electrode can be detected by inductively coupled plasma (ICP) testing. For details, please refer to YS / T1006.2-2014, GB / T23367.2-2009 or YS / T1028.5-2015. Use an inductively coupled plasma emission spectrometer (iCAP 740) and measure according to the instrument's instruction manual to obtain the fluorine content of the positive electrode.

[0322] 2. LUMO level testing

[0323] The LUMO energy levels of each substance can be obtained by referring to "Diphenyl Ketone towards Ultra-stable Hard Carbon Anodes for Sodium-Ion Batteries" (Angewandte Chemie, 2022. DOI:10.1002 / anie.202214717) based on first-principles calculations, specifically using density functional theory (DFT). The theoretical calculations were performed using Gaussian 09 software and a Becke three-parameter Li-Yang-Pahr (B3LYP) mixed functional. To obtain accurate geometric structures, no symmetry constraints were applied during the structure optimization process. The energy and force convergence thresholds were set to [value missing] for each atom. and Furthermore, atomic properties are represented by the 6-311+G(d) basis set. Dispersion-corrected density functional theory (DFT-D2) calculations were performed using the Vienna Ab initio Simulation Package (VASP), employing the generalized gradient approximation (GGA) and the Perdew-Burke-Eznerhof (PBE) functional (GGA-PBE) to describe the exchange-related energies of electrons. The projection-enhanced wave method (PAW) was used to handle the nucleus-electron interactions. The k-point on the Brillouin zone was 5×5×1, with an energy cutoff of 400 eV. Atomic positions and cell vectors were fully optimized until all force components were less than 1. The LUMO energy level of a substance can be obtained using the simulation calculation method described above.

[0324] The LUMO energy levels of the metallic states corresponding to the metal elements in this application and / or the solvents of the electrolyte can also be obtained by referring to books and literature already published in the prior art.

[0325] Calculations showed that the LUMO1 energy level in the examples and comparative examples was -0.57.

[0326] y = LUMO2 level - LUMO1 level.

[0327] 3. Battery performance testing

[0328] (1) Charge capacity, discharge capacity and initial coulombic efficiency test

[0329] After assembling the battery and letting it rest for 10 hours at 25℃, the first charge-discharge test was conducted. First, the secondary battery was charged to 3.65V with a constant current of 0.33C. Then, it was charged to 0.05C with a constant voltage of 3.65V, and the charging capacity was recorded as C1. Next, it was discharged to the lower cutoff voltage of 1.5V with a constant current of 0.33C, and the discharge capacity was recorded as C2. The initial coulombic efficiency FCE = C2 / C1.

[0330] The specific capacity data corresponding to the charging and discharging steps are the charging specific capacity and the discharging specific capacity (if only the capacity value can be read, the capacity needs to be divided by the mass of the corresponding positive electrode material that provides all the activity).

[0331] (2) Cyclic performance - Cyclic capacity retention

[0332] After battery formation at 25℃, it is first discharged at a constant current of 0.33C to the lower cutoff voltage of 1.5V; then charged at a constant current of 0.33C to 3.65V, and then charged at a constant voltage of 3.65V to a current of 0.05C; then discharged again at a constant current of 0.33C to the lower cutoff voltage of 1.5V, and the discharge capacity at this point is recorded as C0; then, the secondary battery is charged at a constant current of 0.33C to 3.65V, charged at a constant voltage of 3.65V to a current of 0.05C, and then discharged again at a constant current of 0.33C to the lower cutoff voltage of 1.5V, and this cycle is repeated 200 times. The presence of internal short circuits in the secondary battery during the cycle is observed. After n cycles, the discharge capacity of the nth cycle is recorded as Cn. Based on the formula: Cn / C0×100%, the cycle capacity retention rate of the 200th cycle is calculated as C200 / C0×100%.

[0333] III. Analysis of Test Results for Each Embodiment and Comparative Example

[0334] Batteries for each embodiment and comparative example were prepared according to the above method, and various performance parameters were measured. The relevant parameters of the metal battery are shown in Table 1-2, and the performance test results are shown in Table 3.

[0335] Table 2 Parameters of Metal Batteries

[0336] Table 3 Performance Test Table for Metal Batteries

[0337] Based on the results in the table above, and as can be seen from Example 11 and Comparative Example 2, with the total mass of the separator as the calculation basis, and controlling the fluorine content of the first adhesive layer in the separator to be less than or equal to 500 ppm and the fluorine content of the second adhesive layer to be less than or equal to 1200 ppm, the metal battery of this application has good discharge specific capacity, initial coulombic efficiency and cycle performance.

[0338] As can be seen from Examples 11 and 3, and Comparative Examples 2 and 3, setting an adhesive layer on the surface of the separator and controlling the fluorine content of the adhesive layer—specifically, controlling the fluorine content of the first adhesive layer to be less than or equal to 500 ppm and the fluorine content of the second adhesive layer to be less than or equal to 1200 ppm—helps improve the cycle performance of the metal battery of this application, while also providing interfacial stability. As can be seen from Comparative Examples 1 and 2, controlling the difference between the lowest unoccupied molecular orbital energy level (LUMO2) of the electrolyte solvent and the lowest unoccupied molecular orbital energy level (LUMO1) of the metallic state corresponding to the metal element in the positive electrode active material to be greater than or equal to 0 helps improve the compatibility between the electrolyte and the negative electrode, thereby improving the discharge capacity, initial coulombic efficiency, and cycle performance of the metal battery.

[0339] As can be seen from Examples 1 and 2-3, the adhesive layer of this application is provided on both sides of the separator, which helps to further improve the cycle performance of the metal battery.

[0340] As can be seen from Examples 1 and 4-6, the metal battery of this application can be applied to various first binders and / or third binders of this application. Among them, the effect is better when the first adhesive layer includes only the first binder, and the first binder is PMMA. When the fluorine content of the first adhesive layer is controlled to be 0 ppm, it helps to further improve the discharge specific capacity, initial coulombic efficiency and cycle performance of the metal battery of this application.

[0341] As can be seen from Examples 1 and 7-8, the metal battery of this application can be applied to various second binders and / or fourth binders of this application. Among them, the effect is better when the second binder layer only includes the second binder, and the second binder is PMMA. When the fluorine content of the second binder layer is controlled at 500 ppm, and further controlled at 0 ppm, it helps to further improve the discharge specific capacity, initial coulombic efficiency and cycle performance of the metal battery of this application.

[0342] As can be seen from Examples 1-15, controlling the fluorine content of the positive electrode sheet, specifically, controlling the fluorine content of the positive electrode sheet to be less than or equal to 350 ppm, and further, controlling it to be less than or equal to 120 ppm, helps to further improve the discharge specific capacity, initial coulombic efficiency and cycle performance of the metal battery of this application.

[0343] As can be seen from Examples 1 and 16, the metal battery of this application can be used with various electrolyte solvents described in this application.

[0344] As can be seen from Examples 1 and 17, the porous layer in the negative electrode sheet of this application is suitable for various porous layer materials described in this application, such as carbon nanotubes or carbon black.

[0345] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A metal battery, characterized by, The metal battery comprises a positive electrode sheet, a negative electrode sheet, and a separator film, the separator film comprises a substrate and at least one adhesive layer arranged on the surface of the substrate, the adhesive layer at least comprises a first adhesive layer arranged between the substrate and the negative electrode sheet and / or a second adhesive layer arranged between the substrate and the positive electrode sheet; The fluorine content of the first adhesive layer is less than or equal to 500 ppm, based on the total mass of the separator film; The fluorine content of the second adhesive layer is less than or equal to 1200 ppm, based on the total mass of the separator film.

2. The metal battery of claim 1, wherein, The fluorine content of the first adhesive layer is equal to 0 ppm, based on the total mass of the separator film; and / or, the fluorine content of the second adhesive layer is less than or equal to 500 ppm, based on the total mass of the separator film.

3. The metal battery of claim 1 or 2, wherein, The positive electrode sheet comprises a positive electrode film layer, the positive electrode film layer comprises a positive electrode active material, the positive electrode active material comprises a metal element, the positive electrode active material releases metal ions during charging, the metal ions are reduced and precipitated as metal at the negative electrode sheet, and the metal is oxidized and dissolved as the metal ions during discharging.

4. The metal battery of any one of claims 1-3, wherein, The first adhesive layer comprises a first adhesive, and the second adhesive layer comprises a second adhesive, the first adhesive and the second adhesive each independently comprise at least one of a methyl methacrylate monomer copolymer and / or homopolymer, a sugar monomer copolymer and / or homopolymer, an acrylic acid monomer copolymer and / or homopolymer, a styrene monomer copolymer and / or homopolymer, a butadiene monomer copolymer and / or homopolymer, a phenol monomer copolymer and / or homopolymer, an aldehyde monomer copolymer and / or homopolymer, a diatomic amine monomer copolymer and / or homopolymer, a diatomic anhydride monomer copolymer and / or homopolymer, a benzene ring monomer copolymer and / or homopolymer, or derivatives, modifications thereof.

5. The metal battery of claim 4, wherein, The first adhesive and the second adhesive each independently comprise at least one of polymethyl methacrylate, carboxymethyl cellulose, polyacrylic acid, sodium alginate, butadiene rubber, polyvinyl alcohol, phenolic resin, polyimide, styrene monomer-butadiene monomer-styrene monomer block copolymer, or derivatives, modifications thereof.

6. The metal battery of any one of claims 1-5, wherein, The first adhesive layer comprises a third adhesive; and / or, the second adhesive layer comprises a fourth adhesive, the third adhesive and the fourth adhesive each independently comprise at least one of a fluorine-containing monomer copolymer and / or homopolymer, or derivatives, modifications thereof.

7. The metal battery of claim 6, wherein, The third adhesive and the fourth adhesive each independently comprise at least one of a vinylidene fluoride monomer copolymer and / or homopolymer, a hexafluoropropylene monomer copolymer, a fluoroethylene monomer copolymer, a trifluoroethylene monomer copolymer, a perfluoromethyl isopropyl ether monomer homopolymer, a tetrafluoroethylene monomer copolymer, a fluoroethylene ester monomer copolymer, a methyl methacrylate monomer copolymer, a fluorostyrene monomer copolymer, or a fluorobenzene monomer copolymer, or derivatives, modifications thereof.

8. The metal battery of any one of claims 6 or 7, wherein, The third binder and the fourth binder each independently include at least one of vinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinyl fluoride-trifluoroethylene, polyperfluoromethyl isopropyl ether, polyvinylidene fluoride-tetrafluoroethylene, polyacrylic acid-fluorovinyl ester, polymethyl methacrylate-fluorostyrene, polystyrene-fluorostyrene, polyester-fluorovinyl ester, polyimide-fluorostyrene, or derivatives thereof, modifications thereof.

9. The metal battery of any one of claims 6-8, wherein, The mass ratio of the first binder and the third binder is (1-0.5):(0:0.5); and / or, the mass ratio of the second binder and the fourth binder is (1-0):(0-1).

10. The metal battery of any one of claims 1-9, wherein, The first adhesive layer has a mass per unit area of 0-0.3 mg / cm 2 ; and / or, the second adhesive layer has a mass per unit area of 0-0.3 mg / cm 2 , wherein the mass per unit area of the first adhesive layer and the second adhesive layer are not both 0 mg / cm 2 .

11. The metal battery of any one of claims 1-10, wherein, The negative electrode tab is an inert material that does not participate in an electrochemical reaction.

12. The metal battery of any one of claims 1-11, wherein, The negative electrode tab includes a porous layer formed on the surface of the negative electrode tab, and the porous layer has micron, submicron or nanoscale pores.

13. The metal battery of claim 12, wherein, The porous layer includes a carbon-based material.

14. The metal battery of claim 13, wherein, The carbon-based material includes at least one of carbon black, activated carbon, carbon nanotubes, carbon fibers or graphite.

15. The metal battery of any one of claims 1-14, wherein, The positive electrode film layer includes a positive electrode film layer binder, and the fluorine content of the positive electrode tab is less than or equal to 385 ppm based on the total mass of the positive electrode film layer. The metal battery includes an electrolyte, and the difference between the lowest unoccupied molecular orbital energy level LUMO2 of the solvent of the electrolyte and the lowest unoccupied molecular orbital energy level LUMO1 of the metal state corresponding to the metal element in the positive electrode active material is y=LUMO2-LUMO1, 0≤y.

16. The metal battery of claim 15, wherein, The fluorine content of the positive electrode tab is less than or equal to 120 ppm based on the total mass of the positive electrode film layer.

17. The metal battery of claim 15 or 16, wherein, 0.7≤y。 18. The metal battery of any one of claims 15-17, wherein, The positive electrode film layer binder includes a fifth binder, and the fifth binder is a copolymer and / or a homopolymer, and the substitution group of the fluorine element in the monomers of the copolymer and the homopolymer is less than or equal to 2.

19. The metal battery of claim 18, wherein, The fifth binder includes at least one of methyl methacrylate monomer copolymer and / or homopolymer, sugar monomer copolymer and / or homopolymer, acrylic acid monomer copolymer and / or homopolymer, styrene monomer copolymer and / or homopolymer, butadiene monomer copolymer and / or homopolymer, phenolic monomer copolymer and / or homopolymer, aldehyde monomer copolymer and / or homopolymer, diamin monomer copolymer and / or homopolymer, dianhydride monomer copolymer and / or homopolymer, benzene ring monomer copolymer and / or homopolymer, or derivatives thereof, modifications thereof.

20. The metal battery of claim 18 or 19, wherein, The fifth binder includes at least one of polymethyl methacrylate, carboxymethyl cellulose, polyacrylic acid, sodium alginate, butadiene rubber, polyvinyl alcohol, phenolic resin, polyimide, styrene monomer-butadiene monomer-styrene monomer block copolymer, or derivatives thereof, modifications thereof.

21. The metal battery of any one of claims 15-20, wherein, The positive electrode film layer binder includes a sixth binder, and the sixth binder includes fluorine-containing monomer copolymer and / or homopolymer, or derivatives thereof, modifications thereof.

22. The metal battery of claim 21, wherein, The mass ratio of the fifth binder and the sixth binder is (1-0.5):(0-0.5).

23. The metal battery of any one of claims 15-22, wherein, The mass percentage content of the positive electrode film layer binder is less than or equal to 3% and greater than or equal to 0.5% based on the total mass of the positive electrode film layer.

24. The metal battery of any one of claims 21-23, wherein, when the mass ratio of the fifth binder and the sixth binder is greater than or equal to 0.5:0.5 and less than 0.6:0.4, the mass percentage content of the positive electrode film layer binder is less than or equal to 2% and greater than or equal to 0.5% based on the total mass of the positive electrode film layer; and / or when the mass ratio of the fifth binder and the sixth binder is greater than or equal to 0.6:0.4 and less than 0.7:0.3, the mass percentage content of the positive electrode film layer binder is less than or equal to 2.5% and greater than or equal to 0.5% based on the total mass of the positive electrode film layer; and / or when the mass ratio of the fifth binder and the sixth binder is (1-0.7):(0-0.3), the mass percentage content of the positive electrode film layer binder is less than or equal to 3% and greater than or equal to 0.5% based on the total mass of the positive electrode film layer.

25. The metal battery of any one of claims 15-24, wherein, The electrolyte comprises a solvent and a sodium salt dissolved in the solvent, the solvent comprising at least one ether compound of formula I, R1-(0-R3) n -O-R2(I) wherein R1and R2are each independently selected from C1-C6alkyl, R3is selected from C1-C6alkylene, and n is selected from an integer from 1 to 5.

26. The metal battery of claim 25, wherein, R1and R2are each independently selected from methyl or ethyl, and R3is selected from a linear C1-C5alkylene.

27. The metal battery of claim 25 or 26, wherein, R3is selected from -CH2CH2-.

28. The metal battery of any one of claims 25-27, wherein, The solvent includes at least one of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, pentaethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, pentaethylene glycol diethyl ether, or ethylene glycol dibutyl ether.

29. The metal battery of any one of claims 1-28, wherein, The metal battery includes a sodium metal battery.

30. The metal battery of any one of claims 1-29, wherein, The positive active material includes Na a1 Ni b1 Fe c1 Mn d1 M1 e1 O f1 , Na x1 M2 y1 M3 y2 (X a2 O b2 ) z1 Z w1 , Prussian blue, Prussian white, or at least one of modified compounds thereof, wherein, M includes at least one of an active or / and inert doped metal element, 0.85≤a1≤1, 0≤b1≤1, 0≤c1≤1, 0≤d1≤1, 0≤e1≤1, 1.8≤f1≤2, b1, c1, d1, and e1 are not simultaneously 0; M2 includes at least one of Ti, V, Cr, Mn, Fe, Ca, Mg, Al, Nb, Co, Zr, M3 includes Ni, X includes at least one of Si, S, P, As, B, Mo, W, Ge, Z includes at least one of F, O, OH, 1≤x1≤7, 1≤y1≤4, 0≤y2≤0.05, 0.2≤a2 / b2≤0.3, 1≤z1≤4, 0≤w1≤7.

31. A method of preparing the metal battery of any one of claims 1-30.

32. An electrical device, comprising: The power consuming device includes the metal battery of any one of claims 1-30 or prepared by the method of claim 31. The power consuming device includes the metal battery of any one of claims 1-30 or prepared by the method of claim 31.

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