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WO2024174066A1 - 隔膜、二次电池及用电装置 - Google Patents

隔膜、二次电池及用电装置 Download PDF

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Publication number
WO2024174066A1
WO2024174066A1 PCT/CN2023/077202 CN2023077202W WO2024174066A1 WO 2024174066 A1 WO2024174066 A1 WO 2024174066A1 CN 2023077202 W CN2023077202 W CN 2023077202W WO 2024174066 A1 WO2024174066 A1 WO 2024174066A1
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WO
WIPO (PCT)
Prior art keywords
optionally
barrier layer
diaphragm
negative electrode
positive electrode
Prior art date
Application number
PCT/CN2023/077202
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English (en)
French (fr)
Other versions
WO2024174066A9 (zh
Inventor
彭畅
陈培培
吴得贵
黄雨铭
刘姣
Original Assignee
宁德时代新能源科技股份有限公司
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Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Priority to PCT/CN2023/077202 priority Critical patent/WO2024174066A1/zh
Publication of WO2024174066A1 publication Critical patent/WO2024174066A1/zh
Publication of WO2024174066A9 publication Critical patent/WO2024174066A9/zh

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application belongs to the technical field of secondary batteries, and specifically relates to a diaphragm, a secondary battery and an electrical device.
  • Secondary batteries are widely used in various consumer electronic products and electric vehicles due to their outstanding features such as light weight, no pollution, and no memory effect. With the continuous development of the new energy industry, users have put forward higher requirements for the use of secondary batteries. For example, high energy density, longer cycle life, and greater environmental adaptability; however, under conditions such as high energy density design, long cycle, and high temperature, the electrodes are often severely damaged, causing battery capacity decay.
  • the present application provides a diaphragm, a secondary battery and an electrical device, aiming to reduce the damage to the electrodes and reduce the battery capacity attenuation.
  • a first aspect of the present application provides a membrane, comprising a barrier layer, wherein the barrier layer comprises a polymer layer and a barrier material at least partially embedded in the polymer layer;
  • the barrier material includes one or more of a micro-mesoporous material and an ion-conducting inorganic material; the volume average particle size Dv50 of the barrier material is denoted as D, the thickness of the barrier layer is denoted as d1, and the volume average particle size Dv50 of the barrier material and the thickness of the barrier layer satisfy: 0.2 ⁇ d1/D ⁇ 1000;
  • the air permeability of the barrier layer is ⁇ 300s/100mL.
  • the present application at least has the following beneficial effects:
  • the diaphragm of the present application includes a barrier layer, which includes a polymer layer and a barrier material.
  • a barrier layer which includes a polymer layer and a barrier material.
  • the air permeability of the barrier layer is ⁇ 300s/100mL. It is more difficult for gas to pass through the barrier layer, indicating that most of the pores in the polymer layer have been filled with the barrier material; compared with gas, the solvent, additive and interface reaction by-products in the positive electrode electrolyte and the negative electrode electrolyte are more difficult to pass through the barrier layer. Only lithium ions can penetrate the barrier layer through the barrier material, which greatly inhibits the solvent, additive and by-product in the electrolyte from passing through the barrier layer, eliminating the battery capacity decay caused by the interaction between the positive and negative electrodes.
  • the air permeability of the barrier layer is ⁇ 500s/100mL; optionally, the air permeability of the barrier layer is ⁇ 800s/100mL.
  • the volume average particle size Dv50 of the barrier material and the thickness of the barrier layer satisfy: 1 ⁇ d1/D ⁇ 500; optionally 1 ⁇ d1/D ⁇ 300.
  • the volume average particle size Dv50 of the barrier material satisfies: 0.005 ⁇ m ⁇ D ⁇ 10 ⁇ m; optionally 0.007 ⁇ m ⁇ D ⁇ 5 ⁇ m; further optionally 0.01 ⁇ m ⁇ D ⁇ 1 ⁇ m.
  • the thickness of the barrier layer satisfies: 0.007 ⁇ m ⁇ d1 ⁇ 50 ⁇ m; optionally, 0.2 ⁇ m ⁇ d1 ⁇ 15 ⁇ m.
  • the micro-mesoporous material comprises one or more of a covalent organic framework material and a metal organic framework material;
  • the ion-conducting inorganic material includes LLZO, LLTO, LATP, LAGP, LSPS, and one or more of coatings, dopants and/or dopants with coating layers of the above substances.
  • the pore size of the internal pores of the micro-mesoporous material is denoted as d2, and the pore size of the internal pores of the micro-mesoporous material satisfies: 0.04nm ⁇ d2 ⁇ 5nm; optionally, 0.3nm ⁇ d2 ⁇ 2nm.
  • the conductivity of the ion-conducting inorganic material is ⁇ 0.0001 mS ⁇ cm -1 at 25°C;
  • the electrical conductivity of the ion-conducting inorganic material is ⁇ 0.001 mS ⁇ cm -1 at 25° C.;
  • the electrical conductivity of the ion-conducting inorganic material is ⁇ 0.01 mS ⁇ cm ⁇ 1 .
  • the area proportion of the barrier material in the barrier layer is 30%-99%; optionally 50%-99%; further optionally 70%-99%.
  • the polymer layer has at least one of the following features (1)-(3):
  • the polymer layer comprises a polymer having a swelling degree ⁇ 10%
  • the polymer includes one or more of polyethylene, polypropylene, polyimide and polyvinylidene fluoride;
  • the mass proportion of the polymer layer in the barrier layer is ⁇ 50%
  • the mass of the polymer layer in the barrier layer is 2%-30%; further optionally, 5%-15%;
  • the polymer layer comprises a polymer having a weight average molecular weight of 1W-200W;
  • the polymer layer comprises a polymer having a weight average molecular weight of 2W-150W;
  • the polymer layer includes a polymer with a weight average molecular weight of 10W-100W.
  • the diaphragm further comprises a supporting layer, and the barrier layer is located on at least one side of the supporting layer.
  • the support layer has at least one of the following features (1)-(3):
  • the support layer has pores, and the average pore size of the pores of the support layer is 20nm-1000nm; optionally 100nm-500nm;
  • the material of the support layer includes one or more of polyethylene, polypropylene, polyimide and polyvinylidene fluoride.
  • the thickness of the diaphragm is 2 ⁇ m-12 ⁇ m; optionally 3 ⁇ m-10 ⁇ m; further optionally 5 ⁇ m-7 ⁇ m.
  • the diaphragm has at least one of the following features:
  • the air permeability of the diaphragm is ⁇ 300s/100mL; optionally, the air permeability of the diaphragm is ⁇ 500s/100mL; further optionally, the air permeability of the diaphragm is ⁇ 800s/100mL;
  • the tensile strength of the diaphragm is ⁇ 1000 MPa; optionally, the tensile strength of the diaphragm is ⁇ 1200 MPa; further optionally, the tensile strength of the diaphragm is ⁇ 1500 MPa.
  • the second aspect of the present application provides a secondary battery, comprising a positive electrode sheet, a negative electrode sheet, a positive electrode electrolyte, a negative electrode electrolyte, and a separator as described in the first aspect of the present application;
  • the isolation membrane is located between the positive electrode plate and the negative electrode plate, the positive electrode electrolyte is located between the positive electrode plate and the isolation membrane, and the negative electrode electrolyte is located between the negative electrode plate and the isolation membrane; one or more of the solvents, lithium salts and additives contained in the positive electrode electrolyte and the negative electrode electrolyte are different.
  • the solvent of the positive electrode electrolyte is different from the solvent of the negative electrode electrolyte
  • the solvent of the positive electrode electrolyte includes one or more of carbonate solvents, fluorocarbonate solvents, fluorocarboxylate solvents, sulfone solvents, fluorosulfone solvents, phosphate solvents, borate solvents and nitrile solvents;
  • the solvent of the negative electrode electrolyte includes one or more of carbonate solvents, carboxylate solvents, ether solvents, fluorinated carboxylate solvents and fluorinated carbonate solvents.
  • the fluorocarbonate solvent includes one or more of methyl trifluoroethyl carbonate, di(trifluoromethyl) carbonate, di(trifluoroethyl) carbonate, 4-trifluoromethyl ethylene carbonate, bisfluoroethylene carbonate, trifluoromethyl trifluoroethyl carbonate, trifluoropropyl carbonate and 2,2-difluoroethyl methyl carbonate;
  • the fluorocarboxylic acid ester solvent includes one or more of trifluoroethyl 3,3,3-trifluoroacetate, 2,2-difluoroethyl acetate, ethyl difluoroacetate and 2,2,2-trifluoroethyl acetate;
  • the sulfone solvent includes one or more of sulfolane, dimethyl sulfone, diethyl sulfone, methyl ethyl sulfone, methyl isopropyl sulfone, dimethyl sulfoxide, diethyl sulfoxide and methyl ethyl sulfoxide;
  • the fluorinated sulfone solvent includes one or more of methyl trifluoromethyl sulfone, ethyl trifluoromethyl sulfone, propyl trifluoromethyl sulfone, methyl trifluoroethyl sulfone, methyl trifluoropropyl sulfone, 1,1,2,2-tetrafluoropropyl methyl sulfone, trifluoromethyl isopropyl sulfone and methyl hexafluoroisopropyl sulfone;
  • the phosphate ester solvent includes one or more of trimethyl phosphate, triethyl phosphate, tripropyl phosphate, isopropyl phosphate, tris(hexafluoroisopropyl) phosphate and tris(2,2,2-trifluoroethyl) phosphate;
  • the borate ester solvent includes one or more of trimethyl borate, triethyl borate, tri(hexafluoroisopropyl) borate and tri(2,2,2-trifluoroethyl) borate;
  • the nitrile solvent includes one or more of acetonitrile, succinonitrile, succinonitrile, glutaronitrile, adiponitrile, 1,4-dicyano-2-butene, 1,3,6-hexanetrinitrile, ethylene glycol dipropionitrile ether and 1,2,3-tricyanoethoxy;
  • the carbonate solvent includes one or more of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and ethylene carbonate;
  • the carboxylate solvent includes one or more of methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate and propyl propionate;
  • the ether solvent includes one or more of 1,2-dimethoxyethane, tetraethanol dimethyl ether, ⁇ -butyrolactone and tetrahydrofuran.
  • the lithium salt of the positive electrode electrolyte is different from the lithium salt of the negative electrode electrolyte
  • the lithium salt of the positive electrode electrolyte includes one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide and lithium bis(oxalatoborate);
  • the lithium salt of the negative electrode electrolyte includes lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide and dioxalatoboric acid.
  • lithium hexafluorophosphate lithium tetrafluoroborate
  • lithium bis(fluorosulfonyl)imide lithium bis(fluorosulfonyl)imide and dioxalatoboric acid.
  • One or more of lithium is lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide and dioxalatoboric acid.
  • a third aspect of the present application provides an electrical device, comprising the secondary battery of the second aspect of the present application.
  • FIG. 1 is a schematic diagram of the structure of COF-1 provided in one embodiment of the present application.
  • FIG. 2 is a schematic diagram of the structure of COF-2 provided in one embodiment of the present application.
  • FIG3 is a schematic diagram of the COF-3 structure provided in one embodiment of the present application.
  • FIG. 4 is a schematic diagram of the structure of COF-4 provided in one embodiment of the present application.
  • FIG. 5 is a schematic diagram of the structure of COF-5 provided in one embodiment of the present application.
  • FIG. 6 is a schematic diagram of the structure of COF-6 provided in one embodiment of the present application.
  • FIG. 7 is a schematic diagram of the structure of COF-7 provided in one embodiment of the present application.
  • FIG. 8 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 9 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 8 .
  • FIG. 10 is a schematic diagram of an electric device using a secondary battery according to an embodiment of the present application as a power source.
  • any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and any upper limit can be combined with any other upper limit to form an unspecified range.
  • each separately disclosed point or single value can itself be combined as a lower limit or upper limit with any other point or single value or with other lower limits or upper limits to form an unspecified range.
  • “Scope” disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range.
  • the scope limited in this way can be including end values or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected.
  • the numerical range "a-b" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers.
  • the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations.
  • a parameter is expressed as an integer ⁇ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • the method may further include step (c), which means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.
  • the “include” and “comprising” mentioned in this application represent open-ended or closed-ended expressions.
  • the “include” and “comprising” may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.
  • the term "or” is inclusive. That is, the phrase “A or (or) B” means “A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B”: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).
  • the terms used in this application have the well-known meanings commonly understood by those skilled in the art.
  • the numerical values of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (for example, they can be tested according to the methods given in the embodiments of this application).
  • the compatibility of some electrolyte components with the positive and negative electrodes is often different. They may have a positive effect on one side and a side effect on the other side. In order to balance the two, the electrolyte design has gradually become more complicated, which limits the personalized design of the battery and also increases the cost of the battery. In order to take into account both the positive and negative electrodes, the solvents and lithium salts that can be selected for the electrolyte are very limited, and the advantages of each electrolyte component cannot be brought into play.
  • the diaphragm provided in the present application includes a barrier layer, which includes a polymer layer and a barrier material at least partially embedded in the polymer layer; wherein the barrier material includes one or more of a micro-mesoporous material and an ion-conducting inorganic material; the volume average particle size Dv50 of the barrier material is denoted as D, and the thickness of the barrier layer is denoted as d1; the volume average particle size Dv50 of the barrier material and the thickness of the barrier layer satisfy: 0.2 ⁇ d1/D ⁇ 1000; the air permeability of the barrier layer is ⁇ 300s/100mL.
  • the barrier material mentioned in this application only allows lithium ions to pass through, while the solvent, additives and interfacial reaction by-products in the electrolyte cannot pass through.
  • the barrier material can be completely embedded in the polymer layer, in which case the thickness of the barrier layer is the same as the thickness of the polymer layer; it can also be partially embedded in the polymer layer and partially exposed outside the polymer layer, in which case the thickness of the barrier layer is the sum of the thickness of the polymer layer and the thickness of the barrier material exposed outside the polymer layer.
  • the polymer layer has a similar function to that of a substrate and can provide space to accommodate the barrier material.
  • the barrier layer may include one barrier material, or may include two or more barrier materials at the same time; when the barrier layer includes two or more barrier materials, the barrier materials may all be micro-mesoporous materials, or may all be ion-conducting inorganic materials, or may include both micro-mesoporous materials and ion-conducting inorganic materials.
  • Micro-mesoporous materials refer to materials having microporous structures and/or mesoporous structures; micropores refer to pores with a pore size less than 2nm, and mesopores refer to pores with a pore size of 2nm-50nm.
  • Ion-conducting inorganic materials refer to materials that can conduct metal ions.
  • the diaphragm of the present application includes a barrier layer, which includes a polymer layer and a barrier material.
  • a barrier layer which includes a polymer layer and a barrier material.
  • the air permeability of the barrier layer is ⁇ 300s/100mL. It is more difficult for gas to pass through the barrier layer, indicating that most of the pores in the polymer layer have been filled with the barrier material; compared with gas, the solvent, additive and interface reaction by-products in the positive electrode electrolyte and the negative electrode electrolyte are more difficult to pass through the barrier layer. Only lithium ions can penetrate the barrier layer through the barrier material, which greatly inhibits the solvent, additive and by-product in the electrolyte from passing through the barrier layer, eliminating the battery capacity decay caused by the interaction between the positive and negative electrodes.
  • the volume average particle size Dv50 of the barrier material and the thickness of the barrier layer mentioned above satisfy: 0.2 ⁇ d1/D ⁇ 1000; for example, it may be 0.2 ⁇ d1/D ⁇ 900, 0.2 ⁇ d1/D ⁇ 800, 0.2 ⁇ d1/D ⁇ 700, 0.2 ⁇ d1/D ⁇ 600, 0.2 ⁇ d1/D ⁇ 500, 0.2 ⁇ d1/D ⁇ 400, 0.2 ⁇ d1/D ⁇ 300, 0.2 ⁇ d1/D ⁇ 200, 0.2 ⁇ d1/D ⁇ 100 or 0.2 ⁇ d1/D ⁇ 50, etc.
  • d1/D When d1/D is less than the above range, the barrier layer is easy to rupture; when d1/D is greater than the above range, the barrier material particles may be stacked too closely, and the barrier material particles may have too many contact surfaces with each other, which may slow down the transmission speed of lithium ions through the barrier material and worsen the battery impedance.
  • d1/D can be 0.2, 1, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900 or 1000, etc.
  • the Dv50 of the barrier material mentioned above refers to the particle size corresponding to 50% of the barrier material in the volume distribution.
  • it can be tested by the following method: laser particle size analysis; place the barrier layer sample in deionized water, ultrasonicate for 5 minutes to ensure that the sample is completely dispersed, and then place the dispersion in the sample tank for testing to obtain the volume average particle size Dv50 of the barrier material.
  • the mass of the barrier layer can be 0.05g-2g
  • the volume of deionized water can be 10mL-20mL.
  • the thickness of the barrier layer mentioned above can be measured by the following method: first calibrate the micrometer, then place the barrier layer sample between the double anvils, gently rotate the sleeve until a sound is heard, and read and record the thickness of the barrier layer.
  • the air permeability of the barrier layer mentioned above is ⁇ 300s/100mL; optionally, the air permeability of the barrier layer is 300s/100mL-5000s/100mL; for example, it can be 300s/100mL-4500s/100mL, 300s/100mL-4000s/100mL, 300s/100mL-3500s/100mL, 300s/100mL-3000s/100mL, 300s/100mL-25 00s/100mL, 300s/100mL-2000s/100mL, 300s/100mL-1900s/100mL, 300s/100mL-1800s/100mL, 300s/100mL-1700s/100mL, 300s/100mL-1600s/100mL, 300s/10 0mL-1500s/100mL, 300s/100mL-1400s/100mL, 300s/100mL-1300s/100mL, 300s/100mL-1200s/100mL, 300s
  • the air permeability of the barrier layer can be 300s/100mL, 400s/100mL, 500s/100mL, 600s/100mL, 700s/100mL, 800s/100mL, 900s/100mL, 1000s/100mL, 1100s/100mL, 1200s/100mL, 1300s/100mL, 1400s/100mL, 1500s/100mL, 1600s/100mL, 1700s/100mL.
  • the air permeability of the above-mentioned diaphragm can be tested by the following method: spread the barrier layer flat, select a flat and oil-free position, place it on the air outlet of the air compressor, and tighten it; after the barrier layer is fixed in the work station, use the gravity of the cylinder floating on the liquid to compress the air in the cylinder. As the air passes through the sample, the cylinder will fall steadily. Measure the time required for a certain volume of air to pass through the sample, and calculate the air permeability based on this. Among them, the volume of the air column is 100CC; the test area is 6.45cm2 ; the sample area is> 6cm ⁇ 6cm.
  • the inventors of the present application have found through in-depth research that when the separator of the present application satisfies the above-mentioned design conditions and optionally satisfies one or more of the following conditions, the storage performance and cycle performance of the secondary battery can be further improved.
  • the air permeability of the barrier layer is ⁇ 500 s/100 mL; optionally, the air permeability of the barrier layer is ⁇ 800 s/100 mL.
  • the air permeability of the barrier layer is 500s/100mL-5000s/100mL; alternatively, the air permeability of the barrier layer is 800s/100mL-5000s/100mL.
  • the volume average particle size Dv50 of the barrier material and the thickness of the barrier layer satisfy: 1 ⁇ d1/D ⁇ 500; optionally 1 ⁇ d1/D ⁇ 300.
  • the volume average particle size Dv50 of the barrier material satisfies: 0.005 ⁇ m ⁇ D ⁇ 10 ⁇ m; for example, it may be 0.005 ⁇ m ⁇ D ⁇ 9 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 8 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 7 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 6 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 5 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 4 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 3 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 2 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 1 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 0.5 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 0.1 ⁇ m, 0.005 ⁇ m ⁇ D ⁇ 0.01 ⁇ m, etc.
  • the barrier material particles When the volume average particle size Dv50 of the barrier material is lower than the above range, the barrier material particles may be stacked too tightly, and there may be too many contact surfaces between the barrier material particles, which may slow down the transmission rate of lithium ions through the barrier material.
  • the volume average particle size Dv50 of the barrier material is within the above range, the possibility of lithium ions penetrating the diaphragm through the barrier material is high, and the contact surface between the barrier material particles can be reduced, reducing the impact on the lithium ion transmission rate.
  • the volume average particle size Dv50 of the barrier material can be 0.005 ⁇ m, 0.01 ⁇ m, 0.05 ⁇ m, 0.1 ⁇ m, 0.5 ⁇ m, 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m or 10 ⁇ m, etc.
  • the volume average particle size Dv50 of the barrier material satisfies: 0.007 ⁇ m ⁇ D ⁇ 5 ⁇ m.
  • the volume average particle size Dv50 of the barrier material satisfies: 0.01 ⁇ m ⁇ D ⁇ 1 ⁇ m.
  • the thickness of the barrier layer satisfies: 0.007 ⁇ m ⁇ d1 ⁇ 50 ⁇ m; for example, it may be 0.007 ⁇ m ⁇ L ⁇ 45 ⁇ m, 0.01 ⁇ m ⁇ L ⁇ 40 ⁇ m, 0.05 ⁇ m ⁇ L ⁇ 35 ⁇ m, 0.1 ⁇ m ⁇ L ⁇ 30 ⁇ m, 0.1 ⁇ m ⁇ L ⁇ 25 ⁇ m, 0.1 ⁇ m ⁇ L ⁇ 20 ⁇ m, 0.1 ⁇ m ⁇ L ⁇ 15 ⁇ m, 0.1 ⁇ m ⁇ L ⁇ 10 ⁇ m, 0.1 ⁇ m ⁇ L ⁇ 5 ⁇ m or 0.1 ⁇ m ⁇ L ⁇ 1 ⁇ m, etc.
  • the thickness of the barrier layer may be 0.007 ⁇ m, 0.01 ⁇ m, 0.05 ⁇ m, 0.1 ⁇ m, 0.5 ⁇ m, 1 ⁇ m, 3 ⁇ m, 5 ⁇ m, 7 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 30 ⁇ m, 40 ⁇ m or 50 ⁇ m, etc.
  • the thickness of the barrier layer satisfies: 0.2 ⁇ m ⁇ d1 ⁇ 15 ⁇ m.
  • the micro-mesoporous material includes one or more of a covalent organic framework material and a metal organic framework material.
  • covalent organic framework materials are a type of crystalline organic porous materials that connect functional units in the form of covalent bonds into a highly ordered two-dimensional stacked layer structure or a specific three-dimensional topological structure based on reversible chemical reactions.
  • COF materials can be homopolymers of multiple monomers or copolymers of multiple monomers.
  • the type of monomers that form the COF material and the number of functional groups that the monomers have that can participate in the polymer reaction determine the configuration of the COF material and also determine the pore size of the internal pores of the COF material; the larger the pore size of the internal pores of the COF material, the more conducive it is to lithium ion transmission, and the smaller the pore size of the internal pores of the COF material, the better the effect of inhibiting the passage of substances other than lithium ions in the electrolyte.
  • the above-mentioned connecting group refers to the connecting group between two adjacent monomer units in the covalent organic framework material.
  • the monomers and the connecting groups between the monomers mentioned above that are polymerized to form the COF material can be determined by the following method: take the barrier layer and soak it in NMP or water for 24 hours; filter the dissolved material powder, and soak it in new NMP solvent or water for 2 hours, and then ultrasonicate it for 2 hours to fully disperse the particles, repeat the cleaning and ultrasonication process for more than 3 times, and finally obtain the COF material, and put it into a vacuum drying oven at 80°C for 24 hours.
  • the X-ray diffraction spectrum is measured by an X-ray powder diffractometer, and the Fourier infrared spectrum and nuclear magnetic resonance spectrum are measured by an infrared spectrometer and a nuclear magnetic resonance spectrometer.
  • the structure of the COF material contained in the isolation film is determined by combining the X-ray diffraction spectrum, Fourier infrared spectrum and nuclear magnetic resonance spectrum of the isolation film, and then the type of monomers forming the COF material and the connecting groups between the monomers are determined.
  • the X-ray powder diffractometer may be a Science Ultima IV X-ray powder diffractometer
  • the infrared spectrometer may be a Bruker ALPHA infrared spectrometer with a wavelength range of 400 cm -1 to 4000 cm -1
  • the nuclear magnetic resonance spectrometer may be a Bruker AV III 400 nuclear magnetic resonance spectrometer.
  • Metal-organic framework materials are a type of crystalline porous materials with a periodic network structure formed by the self-assembly of inorganic metal centers and bridging organic ligands.
  • the inorganic metal centers can be one or more of metal ions and metal clusters.
  • the ion-conducting inorganic material includes LLZO, LLTO, LATP, LAGP, LSPS, and one or more of coatings, dopants, and/or dopants with coating layers thereof.
  • LLZO is a lithium lanthanum zirconium oxide solid electrolyte
  • LLTO is a lithium lanthanum titanium oxide solid electrolyte
  • LATP is a lithium aluminum titanium phosphate solid electrolyte
  • LAGP is Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3
  • LSPS is a sulfide solid electrolyte.
  • LLZO, LLTO, LATP, and LAGP have synthetic conductivity and good stability, and LSPS has significantly high conductivity and good ion-conducting performance.
  • the above-mentioned ion-conducting inorganic materials can conduct lithium ions to allow them to penetrate the barrier layer.
  • the coating refers to a substance obtained by forming a coating layer on at least part of the outer surface of each of the above-mentioned materials.
  • the dopant refers to a substance formed by adding one or more transition metal elements and non-transition metal elements to each of the above-mentioned materials.
  • the dopant with a coating layer refers to a substance obtained by forming a coating layer on at least part of the outer surface of the dopant of each of the above-mentioned materials.
  • the pore size of the internal pores of the micro-mesoporous material is recorded as d2, and the pore size of the internal pores of the micro-mesoporous material satisfies: 0.04nm ⁇ d2 ⁇ 5nm; for example, it can be 0.04nm ⁇ d2 ⁇ 4.5nm, 0.1nm ⁇ d2 ⁇ 4nm, 0.1nm ⁇ d2 ⁇ 3nm, 0.1nm ⁇ d2 ⁇ 2nm, 0.1nm ⁇ d2 ⁇ 1nm or 0.1nm ⁇ d2 ⁇ 0.5nm, etc.
  • the pore size of the internal pores of the micro-mesoporous material satisfies the above range, only the desolvated lithium ions are allowed to penetrate the diaphragm through the internal pores of the micro-mesoporous material, and other substances other than lithium ions in the electrolyte are prevented from penetrating the diaphragm, thereby inhibiting the interaction between the positive electrode and the negative electrode.
  • the pore size of the internal pores of the micro-mesoporous material may be 0.04 nm, 0.1 nm, 0.3 nm, 0.4 nm, 0.7 nm, 1 nm, 1.3 nm, 1.5 nm, 1.8 nm, 2 nm, 3 nm, 4 nm or 5 nm, etc.
  • the pore size of the internal pores of the micro-mesoporous material satisfies: 0.3 nm ⁇ d2 ⁇ 2 nm, which can further enhance the inhibitory effect on the interaction between the positive and negative electrodes.
  • the pore size of the internal pores of the COF material mentioned above can be measured by the following method: take the barrier layer and soak it in NMP or water for 24 hours; filter the dissolved material powder and soak it in new NMP solvent or water for 2 hours, then ultrasonicate it for 2 hours to fully disperse the particles, repeat the ultrasonic cleaning process for more than 3 times, and finally obtain the COF material, and put it into a vacuum drying oven at 80°C for 24 hours.
  • NLDFT delocalized density functional theory model
  • the inorganic metal center and the organic ligands forming the MOF material determine the structure of the MOF material, and the structure of the MOF material determines the pore size of the internal pores.
  • the pore size of the internal pores of the MOF material mentioned above can be measured by the following method: soak the barrier layer in NMP or water for 24 hours; filter the dissolved material powder and soak it in new NMP solvent or water for 2 hours, and then ultrasonicate it for 2 hours. To make the particles fully dispersed, the ultrasonic cleaning process was repeated more than 3 times, and finally the MOF material was obtained and placed in a vacuum drying oven at 80°C for 24 hours.
  • the adsorption of N 2 by the MOF material was tested at standard atmospheric pressure (101kPa) using a gas adsorption instrument, and the purity of the gas used in the test was 99.999%; 100 mg of MOF material was added to a quartz sample tube and vacuum degassed at 120°C for 6 hours on the pretreatment station of the rapid specific surface area analyzer.
  • the gas adsorption experiment was carried out on the MOF material using a gas adsorption instrument.
  • NLDFT delocalized density functional theory model
  • the conductivity of the ion-conducting inorganic material is ⁇ 0.0001 mS ⁇ cm -1 at 25°C; when the conductivity of the ion-conducting inorganic material is lower than the above range, the battery impedance may increase and the battery kinetic performance may deteriorate.
  • the conductivity of the ion-conducting inorganic material is ⁇ 0.001 mS ⁇ cm -1 at 25°C. Further optionally, the conductivity of the ion-conducting inorganic material is ⁇ 0.01 mS ⁇ cm -1 at 25°C.
  • the conductivity of the ion-conducting inorganic material mentioned above can be measured by the following method: the ion-conducting inorganic material is made into a solid electrolyte ceramic sample, and the solid electrolyte ceramic sample is subjected to an AC impedance test by a CHI660E electrochemical workstation, and the sample with conductive silver paste as an electrode is clamped with a test clip (i.e., silver is plated on both sides of the electrolyte disc), and the test frequency range is 10 ⁇ 6Hz-0.1Hz.
  • the total impedance value is obtained by analyzing the impedance spectrum obtained by the test, and then the corresponding total ion conductivity is calculated.
  • ⁇ is the ionic conductivity, in units of mS ⁇ cm -1
  • d is the thickness of the electrolyte sheet, in units of cm
  • R is the impedance value of the electrolyte sheet measured by the electrochemical workstation, in units of ohms
  • P is the bottom area of the electrolyte sheet, in units of cm2 .
  • the area ratio of the barrier material in the barrier layer is 30%-99%; for example, it can be 35%-99%, 40%-99%, 50%-99%, 60%-99%, 70%-99%, 80%-99% or 90%-99%.
  • the unit area ratio of the barrier material in the barrier layer is lower than the above range, it may result in too few lithium ion transmission channels, which may increase the battery impedance.
  • the unit area ratio of the barrier material in the barrier layer is 30%, 40%, 50%0, 60%0, 70%, 80%, 90% or 99%, etc.
  • the unit area ratio of the barrier material in the barrier layer is 50%-99%.
  • the unit area ratio of the barrier material in the barrier layer is 70%-99%.
  • the area ratio refers to the ratio of the area of the barrier material to the total area of the barrier layer.
  • the area ratio of the barrier material in the barrier layer can be tested by the following method: use a scanning electron microscope to take a SEM image of the barrier layer, and calculate the total area of the barrier material and the area of the barrier layer based on the SEM image of the barrier layer; according to the formula: total area of the barrier material/area of the barrier layer, calculate the area ratio of the barrier material in the barrier layer.
  • the polymer layer includes a polymer with a swelling degree of ⁇ 10%.
  • the swelling degree of the polymers contained in the polymer layer is ⁇ 10%. When the swelling degree of the polymer meets the above range, it may not swell in the electrolyte solvent, has good stability, and can inhibit the electrolyte from penetrating the barrier layer.
  • the polymer includes one or more of polyethylene, polypropylene, polyimide and polyvinylidene fluoride.
  • the polymer layer may include only one polymer, or may include two or more polymers at the same time.
  • the mass proportion of the polymer layer in the barrier layer is ⁇ 50%; when the mass proportion of the polymer in the barrier layer exceeds the above range, the lithium ion transmission speed may be significantly slowed down and the battery impedance may be deteriorated.
  • the mass of the polymer layer in the barrier layer accounts for 2%-30%, for example, 2%-25%, 2%-20%, 2%-15%, 2%-10% or 2%-5%, etc.
  • the mass of the polymer layer in the barrier layer may account for 2%, 5%, 10%, 15%, 20%, 25% or 30%, etc. Further optionally, the mass of the polymer layer in the barrier layer accounts for 5%-15%.
  • the mass proportion of the above-mentioned polymer layer in the barrier layer can be tested by the following method: Use a thermogravimetric-differential scanning calorimeter to analyze the components of the barrier layer: Take 15-25 mg of the barrier layer, place it in an alumina crucible, use nitrogen as a protective gas, preheat at 25°C for 30 minutes, and then heat to 600°C at a rate of 2°C/10min. Determine the content of each component based on the weight change and heat change.
  • the polymer layer includes a polymer having a weight average molecular weight of 1W-200W.
  • the weight average molecular weight of the polymer contained in the polymer layer is 1W-200W; for example, it can be 1W-180W, 1W-160W, 1W-140W, 1W-120W, 1W-100W, 1W-80W, 1W-60W, 1W-40W or 1W-20W, etc.
  • the weight average molecular weight of the polymer contained in the polymer layer is lower than the above range, it may not meet the strength requirements of the barrier layer.
  • the weight average molecular weight of the polymer contained in the polymer layer is The amount can be 1W, 10W, 20W, 30W, 40W, 50W, 60W, 70W, 80W, 90W, 100W, 110W, 120W, 130W, 140W, 150W, 160W, 170W, 180W, 190W or 200W, etc.
  • the polymer layer includes a polymer with a weight average molecular weight of 2W-150W. Further optionally, the polymer layer includes a polymer with a weight average molecular weight of 10W-100W.
  • the weight average molecular weight of the above-mentioned polymers can be measured by gel permeation chromatography (GPC).
  • the diaphragm further comprises a support layer, and the barrier layer is located on at least one side of the support layer.
  • the support layer has pores, and the average pore size of the pores of the support layer is 20nm-1000nm; for example, it can be 20nm-900nm, 20nm-800nm, 20nm-700nm, 20nm-600nm, 20nm-500nm, 20nm-400nm, 20nm-300nm, 20nm-200nm or 20nm-100nm, etc.
  • the average pore size of the pores of the support layer can be 20nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm or 1000nm, etc.
  • the average pore size of the pores of the support layer is 100nm-500nm.
  • the average pore size of the pores in the support layer mentioned above can be tested by the following method: the pore size of the diaphragm is tested using an pore size testing instrument, the sample to be tested is cut into discs with a diameter of 0.5 cm, soaked in the infiltration liquid for 10 minutes, transferred to the fixture with tweezers, the pressure range is set to 0-500PSI, and the pore size test is performed.
  • the material of the support layer includes one or more of polyethylene, polypropylene, polyimide and polyvinylidene fluoride.
  • the thickness of the diaphragm is 2 ⁇ m-12 ⁇ m; for example, it can be 2 ⁇ m-11 ⁇ m, 2 ⁇ m-10 ⁇ m, 2 ⁇ m-9 ⁇ m, 2 ⁇ m-8 ⁇ m, 2 ⁇ m-7 ⁇ m, 2 ⁇ m-6 ⁇ m, 2 ⁇ m-5 ⁇ m, 2 ⁇ m-4 ⁇ m or 2 ⁇ m-3 ⁇ m, etc.
  • the strength of the diaphragm can be further improved.
  • the thickness of the diaphragm can be 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 11 ⁇ m or 12 ⁇ m, etc.
  • the thickness of the diaphragm is 3 ⁇ m-10 ⁇ m. Further optionally, the thickness of the diaphragm is 5 ⁇ m-7 ⁇ m.
  • the thickness of the above-mentioned diaphragm can be tested by the following method: first calibrate the micrometer, then place the diaphragm between the double anvils, gently rotate the sleeve until a sound is heard, and read and record the thickness of the diaphragm.
  • the air permeability of the separator is ⁇ 300s/100mL.
  • the air permeability of the separator meets the above range, it can promote close contact between the polymer layer and the barrier material, the barrier layer has no gaps, reduce the transmission of the positive electrode electrolyte, the negative electrode electrolyte and the interface byproducts, and inhibit the interaction between the positive and negative electrodes.
  • the air permeability of the separator is ⁇ 400s/100mL; further optionally, the air permeability of the separator is ⁇ 500s/100mL.
  • air permeability refers to the time it takes for a certain volume of air to pass through a membrane per unit area under unit pressure.
  • the air permeability of the above-mentioned diaphragm can be tested by the following method: flatten the diaphragm, select a flat and oil-free position, place it at the outlet of the air compressor cylinder, and tighten it; after the diaphragm is fixed in the workstation, use the gravity of the cylinder floating on the liquid to compress the air in the cylinder. As the air passes through the sample, the cylinder will fall steadily. Measure the time required for a certain volume of air to pass through the sample, and calculate the air permeability based on this. Among them, the volume of the air column is 100CC; the test area is 6.45cm2 ; the sample area is>6cm ⁇ 6cm.
  • the tensile strength of the separator is ⁇ 1000MPa.
  • the strength of the barrier layer can be further improved, so that the barrier layer can maintain good structural strength during the use of the battery cell.
  • the tensile strength of the separator is ⁇ 1200MPa; further optionally, the tensile strength of the separator is ⁇ 1500MPa.
  • the tensile strength of the above-mentioned diaphragm can be tested by the following method: cut the diaphragm into 15cm*2cm and measure its thickness as A; then clamp the diaphragm on the universal tester, input the parameters A and 15cm, and start measuring; when the diaphragm is broken, the tensile strength will be displayed and the tensile strength can be read.
  • the present application also provides a method for preparing a diaphragm, comprising the following steps: preparing a solution containing a polymer; loading the solution on a carrier to prepare a polymer layer; loading a barrier material on the surface of the polymer layer before the polymer layer is formed into a film; embedding the barrier material into the polymer layer by rolling, drying, and removing the carrier to prepare the barrier layer.
  • the mass percentage concentration of the solution containing the polymer can be 2%-20%, optionally 3%-7%.
  • the solvent used in preparing the solution containing the polymer includes N-methylpyrrolidone.
  • the carrier includes a glass plate.
  • the thickness of the polymer layer is 4 ⁇ m-6 ⁇ m.
  • the solution is loaded on the carrier by a scraping method. Further optionally, the height of the scraper used in scraping is 10 ⁇ m, and the speed of the coater is 25mm/s-35mm/s.
  • the drying temperature is 75°C-85°C, and the drying time is 10h-14h.
  • the preparation method of the diaphragm includes the following steps: dissolving a polymer in a solvent until it is clear to obtain a solution with a mass percentage concentration of 3%-7%; applying the solution on a glass plate with a coating thickness of 4 ⁇ m-6 ⁇ m to obtain a polymer layer loaded on the glass plate, wherein the height of the scraper used in the scraping is 10 ⁇ m, and the coating machine drives the scraper to move at a speed of 25mm/s-35mm/s; Before the polymer layer is formed into a film, the barrier material is evenly sprayed on the surface of the polymer layer, and then the barrier material is embedded in the polymer layer by rolling. The polymer layer is placed in a vacuum drying oven at 75°C-85°C for 10h-14h, and the glass plate is removed to obtain the barrier layer.
  • the present application also provides a method for preparing a diaphragm, comprising the following steps: preparing a slurry containing a polymer and a barrier material; placing the base membrane in a filtration device; adding the slurry to the filtration device, filtering, and drying to prepare a barrier layer.
  • the solvent used in preparing the slurry containing the polymer and the barrier material includes N-methylpyrrolidone.
  • the mixed solution of the polymer, the barrier material and the solvent is dispersed at 800rpm-1200rpm for 10h-14h.
  • the base film includes a PE film.
  • the filtration equipment includes a Buchner funnel.
  • the filtration time is 1.5h-2.5h.
  • the drying temperature is 75°C-85°C, and the drying time is 10h-14h.
  • the preparation method of the diaphragm includes the following steps: dissolving the polymer in a solvent until it is clear, adding a barrier material, dispersing at 800rpm-1200rpm for 10h-14h to obtain a slurry; placing a PE film on a Buchner funnel, spreading it flat in the Buchner funnel, adding the slurry, and filtering for 1.5h-2.5h; then adding deionized water to the Buchner funnel to wash away the residual slurry; removing the PE film from the Buchner funnel and placing it in a vacuum drying oven at 75°C-85°C for 10h-14h to obtain a barrier layer.
  • the present application also provides a method for preparing a diaphragm, comprising the following steps: preparing a solution containing a polymer; placing the solution on at least one side of a support layer to prepare a polymer layer; before the polymer layer is formed into a film, loading a barrier material on the surface of the polymer layer; embedding the barrier material into the polymer layer by rolling, and drying to prepare a diaphragm.
  • the mass percentage concentration of the solution containing the polymer can be 2%-20%, optionally 3%-7%.
  • the solvent used in preparing the solution containing the polymer includes N-methylpyrrolidone.
  • the carrier includes a glass plate.
  • the thickness of the polymer layer is 4 ⁇ m-6 ⁇ m.
  • the solution is loaded on the carrier by a scraping method. Further optionally, the height of the scraper used in scraping is 10 ⁇ m, and the speed of the coater is 25mm/s-35mm/s.
  • the drying temperature is 75°C-85°C, and the drying time is 10h-14h.
  • the above-mentioned preparation method can be used to prepare a diaphragm comprising both a barrier layer and a support layer.
  • the preparation method of the diaphragm includes the following steps: dissolving the polymer in a solvent until it is clarified to obtain a solution with a mass percentage concentration of 3%-7%; coating the solution on a PE base film with a coating thickness of 4 ⁇ m-6 ⁇ m to obtain a polymer layer loaded on the PE base film, wherein the height of the scraper used in the scraping is 10 ⁇ m, and the coater drives the scraper to move at a speed of 25mm/s-35mm/s; before the polymer layer is formed into a film, the barrier material is evenly sprayed on the surface of the polymer layer, and the barrier material is embedded in the polymer layer by rolling; and then dried in a vacuum drying oven at 75°C-85°C for 10h-14h to obtain a diaphragm.
  • the present application also provides a method for preparing a diaphragm, comprising the following steps: preparing a slurry containing a polymer and a barrier material; placing the slurry on a support layer, drying, and preparing a primary treatment barrier layer; placing the primary treatment barrier layer in a filtration device; adding a solution containing a polymer to the filtration device, filtering, and drying to prepare a diaphragm.
  • the solvent used in preparing the slurry containing the polymer and the barrier material includes N-methylpyrrolidone.
  • the mixed solution of the polymer, the barrier material and the solvent is dispersed at 1800rpm-2200rpm for 10h-14h.
  • the base film includes a PE film.
  • the filtration equipment includes a Buchner funnel.
  • the filtration time is 1.5h-2.5h.
  • the drying temperature is 75°C-85°C, and the drying time is 10h-14h.
  • the above-mentioned preparation method can be used to prepare a diaphragm comprising both a barrier layer and a support layer.
  • the preparation method of the diaphragm includes the following steps: dissolving the polymer in a solvent until it is clear, adding a barrier material, dispersing at 1800rpm-2200rpm for 10-14h to obtain a slurry; scraping the solution on a PE film with a coating thickness of 1.5 ⁇ m-2.5 ⁇ m, wherein the height of the scraper used in the scraping is 5 ⁇ m, and the coater drives the scraper to move at a speed of 25mm/s-35mm/s; then placing it in a vacuum drying oven at 75°C-85°C for 10h-14h to obtain a once-treated barrier layer loaded on the PE film; spreading the PE film and the once-treated barrier layer in a Buchner funnel, adding a polymer solution with a mass percentage concentration of 3%-5%, and filtering for 1.5h-2.5h; then adding deionized water to the Buchner funnel to wash away the residual polymer solution; removing the PE film from the Buchner funnel and placing it in a vacuum drying oven at 75°
  • the present application also provides a secondary battery, comprising a positive electrode sheet, a negative electrode sheet, a positive electrode electrolyte, a negative electrode electrolyte and the above-mentioned separator of the present application; the separator is located between the positive electrode sheet and the negative electrode sheet, the positive electrode electrolyte is located between the positive electrode sheet and the separator, and the negative electrode electrolyte is located between the negative electrode sheet and the separator; one or more of the solvent, lithium salt and additive contained in the positive electrode electrolyte and the negative electrode electrolyte are different. As a result, the storage performance and cycle performance of the obtained secondary battery are significantly improved.
  • the positive electrode sheet and the negative electrode sheet can be stacked and placed close to the separator, and then the three can be placed in an aluminum-plastic bag with the same length and width as the separator.
  • the separator and the aluminum-plastic bag have the same length and width, the other three sides except the opening of the aluminum-plastic bag can be heat-sealed together with the separator, and the separator and the aluminum-plastic bag form a high-density positive electrode chamber and
  • the positive electrode chamber is formed by injecting the positive electrode electrolyte and the negative electrode electrolyte into the positive electrode chamber and the negative electrode chamber respectively from the opening of the aluminum-plastic bag, and finally the opening of the aluminum-plastic bag is heat-sealed to obtain a battery cell, and the battery cell is placed in a shell, for example, the shell can be a steel shell, to obtain a secondary battery.
  • the positive electrode sheet, the negative electrode sheet and the separator when preparing a secondary battery, can be wound and then put into an aluminum-plastic bag, and the lower end of the aluminum-plastic bag is heat-sealed together with the separator, and the separator and the aluminum-plastic bag form a positive electrode chamber and a negative electrode chamber with a high density, and then the positive electrode electrolyte and the negative electrode electrolyte are respectively injected into the positive electrode chamber and the negative electrode chamber from the opening of the aluminum-plastic bag, and finally the opening of the aluminum-plastic bag is heat-sealed to obtain a battery cell, and the battery cell is placed in a shell, for example, the shell can be a steel shell, to obtain a secondary battery.
  • the shell can be a steel shell
  • the compatibility of solvents, lithium salts and additives with the positive electrode and the negative electrode is often different, so it is usually necessary to use solvents, lithium salts and additives in combination to protect the positive electrode and the negative electrode at the same time.
  • the diaphragm can inhibit the exchange of the positive electrode electrolyte and the negative electrode electrolyte
  • the electrolyte can be designed separately according to the characteristics of the positive electrode and the negative electrode themselves without considering the compatibility with the other side; therefore, the advantages of different electrolytes can be further amplified, the performance of the battery cell can be improved, and the limit design of the electrolyte can be pushed.
  • the solvent of the positive electrode electrolyte is different from the solvent of the negative electrode electrolyte.
  • the separator separates the positive electrode electrolyte from the negative electrode electrolyte
  • the positive electrode electrolyte and the negative electrode electrolyte can use solvent systems that match them respectively.
  • the positive electrode electrolyte can use an oxidation-resistant solvent system, which can greatly reduce electrolyte oxidation and improve battery performance
  • the negative electrode electrolyte can use a solvent system that is compatible with the negative electrode and has a low viscosity, which can significantly improve the interface stability of the negative electrode and increase the transmission rate of lithium ions at the negative electrode.
  • the type of solvent used in the positive electrode electrolyte when the type of solvent used in the positive electrode electrolyte is completely different from the type of solvent used in the negative electrode electrolyte, it belongs to the category of the solvent of the positive electrode electrolyte and the solvent of the negative electrode electrolyte being different. For example, if the solvent used in the positive electrode electrolyte is E and the solvent used in the negative electrode electrolyte is F, then the solvent of the positive electrode electrolyte is different from the solvent of the negative electrode electrolyte.
  • both the positive electrode electrolyte and the negative electrode electrolyte use a mixture of multiple solvents, and the types of solvents used in the positive electrode electrolyte and the negative electrode electrolyte are the same, but the volume ratio or mass ratio of different solvents is different, it also falls into the category of different solvents for the positive electrode electrolyte and the negative electrode electrolyte.
  • the solvent used in the positive electrode electrolyte is a mixture of E and F in a volume ratio of 5:5
  • the solvent used in the negative electrode electrolyte is a mixture of E and F in a volume ratio of 3:7
  • the solvent of the positive electrode electrolyte is different from the solvent of the negative electrode electrolyte.
  • the solvent used in the positive electrode electrolyte and the negative electrode electrolyte When the types of solvents used in the positive electrode electrolyte and the negative electrode electrolyte are partially the same, it also falls into the category of different solvents for the positive electrode electrolyte and the negative electrode electrolyte. For example, if the solvent used in the positive electrode electrolyte is E, and the solvent used in the negative electrode electrolyte is a mixture of E and F, then the solvents for the positive electrode electrolyte and the negative electrode electrolyte are different. If the solvent used in the positive electrode electrolyte is a mixture of E and G, and the solvent used in the negative electrode electrolyte is a mixture of E and F, then the solvents for the positive electrode electrolyte and the negative electrode electrolyte are also different.
  • the solvent of the positive electrode electrolyte includes one or more of carbonate solvents, fluorinated carbonate solvents, fluorinated carboxylate solvents, sulfone solvents, fluorinated sulfone solvents, phosphate solvents, borate solvents and nitrile solvents.
  • the solvent of the negative electrode electrolyte includes one or more of carbonate solvents, carboxylate solvents, ether solvents, fluorinated carboxylate solvents and fluorinated carbonate solvents.
  • the fluorocarbonate solvent includes one or more of methyl trifluoroethyl carbonate, bis(trifluoromethyl) carbonate, bis(trifluoroethyl) carbonate, 4-trifluoromethyl ethylene carbonate, bisfluoroethylene carbonate, trifluoromethyl trifluoroethyl carbonate, trifluoropropyl carbonate and 2,2-difluoroethyl methyl carbonate;
  • the fluorocarboxylate solvent includes one or more of trifluoroethyl 3,3,3-trifluoroacetate, 2,2-difluoroethyl acetate, ethyl difluoroacetate and 2,2,2-difluoroethyl acetate.
  • trifluoroethyl esters include one or more of sulfolane, dimethyl sulfone, diethyl sulfone, methyl ethyl sulfone, methyl isopropyl sulfone, dimethyl sulfoxide, diethyl sulfoxide and methyl ethyl sulfoxide; fluorosulfone solvents include one or more of methyl trifluoromethyl sulfone, ethyl trifluoromethyl sulfone, propyl trifluoromethyl sulfone, methyl trifluoroethyl sulfone, methyl trifluoropropyl sulfone, 1,1,2,2-tetrafluoropropyl methyl sulfone, trifluoromethyl isopropyl sulfone and methyl hexafluoroisopropyl sulfone; phosphate
  • the solvent of the positive electrode electrolyte includes one or more of bis(trifluoromethyl)carbonate, bis(trifluoroethyl)carbonate, bis(trifluoroethylene carbonate), 2,2-difluoroethyl acetate, ethyl difluoroacetate, diethyl sulfone, methyl ethyl sulfone, methyl trifluoromethyl sulfone, ethyl trifluoromethyl sulfone, triethyl phosphate, tripropyl phosphate, acetonitrile, succinonitrile and succinonitrile.
  • the solvent of the negative electrode electrolyte includes dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate and ethylene carbonate, 1,2-dimethyl carbonate, One or more of ethylene oxide and tetraethanol dimethyl ether.
  • the lithium salt of the positive electrode electrolyte is different from the lithium salt of the negative electrode electrolyte.
  • the type of lithium salt contained in the positive electrode electrolyte when the type of lithium salt contained in the positive electrode electrolyte is completely different from the type of lithium salt contained in the negative electrode electrolyte, it belongs to the category of different lithium salts in the positive electrode electrolyte and the negative electrode electrolyte. For example, if the lithium salt contained in the positive electrode electrolyte is a and the lithium salt used in the negative electrode electrolyte is b, then the lithium salt in the positive electrode electrolyte is different from the lithium salt in the negative electrode electrolyte.
  • the lithium salt in the positive electrode electrolyte and the lithium salt in the negative electrode electrolyte are different.
  • the lithium salt contained in the positive electrode electrolyte is a, and the molar concentration is 1 mol/L; the lithium salt used in the negative electrode electrolyte is a, and the molar concentration is 1.5 mol/L, then the lithium salt in the positive electrode electrolyte is different from the lithium salt in the negative electrode electrolyte.
  • the positive electrode electrolyte and the negative electrode electrolyte both use a variety of lithium salts, and the types of lithium salts used in the positive electrode electrolyte and the negative electrode electrolyte are exactly the same, but the mass ratio or molar ratio between the different lithium salts is different, which also falls into the category of different lithium salts in the positive electrode electrolyte and the negative electrode electrolyte.
  • the lithium salt in the positive electrode electrolyte is a mixture of a and b with a molar ratio of 5:5
  • the lithium salt in the negative electrode electrolyte is a mixture of a and b with a molar ratio of 3:7
  • the lithium salt in the positive electrode electrolyte is different from the lithium salt in the negative electrode electrolyte.
  • the types of lithium salts in the positive electrode electrolyte and the molar ratio or mass ratio between the different lithium salts are exactly the same, but the total mass volume concentration or total molar concentration of the lithium salt is different, it also falls into the category of different lithium salts in the positive electrode electrolyte and the negative electrode electrolyte.
  • the lithium salt in the positive electrode electrolyte and the lithium salt in the negative electrode electrolyte are both a mixture of a and b in a molar ratio of 5:5, but the total molar concentration of the lithium salt in the positive electrode electrolyte is 1 mol/L, and the total molar concentration of the lithium salt in the negative electrode electrolyte is 1.5 mol/L, then the lithium salt in the positive electrode electrolyte is different from the lithium salt in the negative electrode electrolyte.
  • the lithium salt of the positive electrode electrolyte is different from the lithium salt of the negative electrode electrolyte.
  • the lithium salt contained in the positive electrode electrolyte is a
  • the lithium salt contained in the negative electrode electrolyte is a mixture of a and b
  • the lithium salt of the positive electrode electrolyte is different from the lithium salt of the negative electrode electrolyte.
  • the lithium salt contained in the positive electrode electrolyte is a mixture of a and c, and the lithium salt contained in the negative electrode electrolyte is a mixture of a and c, then the lithium salt of the positive electrode electrolyte is also different from the lithium salt of the negative electrode electrolyte.
  • the lithium salt of the positive electrode electrolyte includes one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, and lithium bis(oxalatoborate).
  • the lithium salt of the positive electrode electrolyte may further include one or more of lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium difluorophosphate (LiPO 2 F 2 ), lithium difluorobisoxalatophosphate (LiDFOP) and lithium tetrafluorooxalatophosphate (LiTFOP).
  • the concentration of the lithium salt in the positive electrode electrolyte is generally 0.5 mol/L-4 mol/L.
  • the lithium salt of the negative electrode electrolyte includes one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(fluorosulfonyl)imide, and lithium bis(oxalatoborate).
  • the lithium salt of the negative electrode electrolyte may further include one or more of lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium difluorophosphate (LiPO 2 F 2 ), lithium difluorobisoxalatophosphate (LiDFOP) and lithium tetrafluorooxalatophosphate (LiTFOP).
  • the concentration of the lithium salt in the negative electrode electrolyte is generally 0.5 mol/L-4 mol/L.
  • the positive electrode electrolyte may further include additives, such as positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • additives such as positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • the negative electrode electrolyte may further include additives, such as negative electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • additives such as negative electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • the positive electrode electrolyte and the negative electrode electrolyte play the role of conducting ions between the positive electrode and the negative electrode.
  • the isolation membrane is set between the positive electrode and the negative electrode, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer arranged on at least one side of the positive electrode current collector, wherein the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the positive electrode active material may include a positive electrode active material for a battery known in the art.
  • the positive electrode active material may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more.
  • lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 , LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (also referred to as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), and LiNi 0.8 Co 0.2 Mn 0.2 O 2 (also referred to as NCM 811 ), lithium
  • lithium phosphates containing olivine structure may include but are not limited to lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.
  • the weight ratio of the positive electrode active material in the positive electrode film layer is 80-100% by weight, based on the total weight of the positive electrode film layer.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • aluminum foil may be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector may be formed by forming a metal material on a polymer material substrate.
  • the metal material includes but is not limited to one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy.
  • the polymer material substrate includes but is not limited to at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS) and polyethylene (PE).
  • the positive electrode film layer may also optionally include a binder.
  • the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • the weight ratio of the binder in the positive electrode film layer is 0-20% by weight, based on the total weight of the positive electrode film layer.
  • the positive electrode film layer may further include a conductive agent.
  • 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.
  • the weight ratio of the conductive agent in the positive electrode film layer is 0-20% by weight, based on the total weight of the positive electrode film layer.
  • the positive electrode sheet can be prepared by the following method: the components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent to form a positive electrode slurry, wherein the positive electrode slurry has a solid content of 40-80wt%, and the viscosity at room temperature is adjusted to 5000-25000mPa ⁇ s, and the solvent may include but is not limited to N-methylpyrrolidone, and the positive electrode slurry is coated on both sides of the positive electrode collector, and after drying, it is cold-pressed by a cold rolling mill to form a positive electrode sheet; the unit surface density of the positive electrode powder coated on one side is 150-450mg/ m2 , and the compaction density of the positive electrode sheet is 2.0-4.3g/ cm3 , and can be optionally 3.5-4.3g/ cm3 .
  • the calculation formula of the compaction density is:
  • Compacted density coating surface density/(thickness of the electrode after extrusion - thickness of the current collector).
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • a metal foil a copper foil may be used.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate.
  • the composite current collector may be formed by forming a metal material on a polymer material substrate.
  • the metal material includes but is not limited to copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.
  • the polymer material substrate includes but is not limited to polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE) and other substrates.
  • the negative electrode active material may adopt the negative electrode active material for batteries known in the art.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used.
  • These negative electrode active materials may be used alone or in combination of two or more.
  • the weight ratio of the negative electrode active material in the negative electrode film layer is 70-100% by weight, based on the total weight of the negative electrode film layer.
  • the negative electrode film layer may further include a binder.
  • the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • SBR styrene-butadiene rubber
  • PAA polyacrylic acid
  • PAAS sodium polyacrylate
  • PAM polyacrylamide
  • PVA polyvinyl alcohol
  • SA sodium alginate
  • PMAA polymethacrylic acid
  • CMCS carboxymethyl chitosan
  • the negative electrode film layer may further include a conductive agent.
  • the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the weight ratio of the conductive agent in the negative electrode film layer is 0-20 weight %, based on the total weight of the negative electrode film layer.
  • the negative electrode film layer may further include other additives, such as thickeners, etc., wherein the thickeners include but are not limited to sodium carboxymethyl cellulose (CMC-Na), etc.
  • the weight ratio of the other additives in the negative electrode film layer is 0-15% by weight, based on the total weight of the negative electrode film layer.
  • the negative electrode sheet can be prepared by the following method: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent to form a negative electrode slurry, wherein the solid content of the negative electrode slurry is 30-70wt%, and the viscosity at room temperature is adjusted to 2000-10000mPa ⁇ s, and the solvent may include but is not limited to deionized water; the obtained negative electrode slurry is coated on the surfaces of both sides of the negative electrode current collector, and after a drying process, cold pressing such as rolling, a negative electrode sheet is obtained.
  • the unit area density of the negative electrode powder coated on one side is 75-220mg/ m2
  • the compaction density of the negative electrode sheet is 1.2-2.0g/ m3 .
  • the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.
  • the positive electrode sheet and the negative electrode sheet are placed close to the isolation film, and then the three are placed in an aluminum-plastic bag with the same length and width as the isolation film.
  • the other three sides except the opening of the aluminum-plastic bag are heat-sealed together with the isolation film.
  • the isolation film and the aluminum-plastic bag form dense positive electrode chamber and negative electrode chamber, and then the positive electrode electrolyte and the negative electrode electrolyte are respectively injected into the positive electrode chamber and the negative electrode chamber from the opening of the aluminum-plastic bag, and finally the opening of the aluminum-plastic bag is heat-sealed to obtain a battery cell.
  • the positive electrode sheet, the negative electrode sheet and the separator can be wound and then put into an aluminum-plastic bag.
  • the lower end of the aluminum-plastic bag is heat-sealed together with the separator.
  • the separator and the aluminum-plastic bag form dense positive electrode chambers and negative electrode chambers.
  • the positive electrode electrolyte and the negative electrode electrolyte are then injected into the positive electrode chamber and the negative electrode chamber respectively from the opening of the aluminum-plastic bag. Finally, the opening of the aluminum-plastic bag is heat-sealed to obtain a battery cell.
  • the secondary battery may include an outer package, which may be used to encapsulate the battery cell.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft package, such as a bag-type soft package.
  • the material of the soft package may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.
  • the secondary battery is a lithium ion battery.
  • FIG8 is a secondary battery 1 of a square structure as an example.
  • the outer package may include a shell 11 and a cover plate 13.
  • the shell 11 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the shell 11 has an opening connected to the receiving cavity, and the cover plate 13 can be covered on the opening to close the receiving cavity.
  • the positive electrode sheet, the negative electrode sheet and the separator can be wound or laminated to form an electrode assembly 12.
  • the electrode assembly 12 is encapsulated in the housing cavity.
  • the positive electrode electrolyte is immersed between the positive electrode sheet and the separator, and the negative electrode electrolyte is immersed between the negative electrode sheet and the separator.
  • the number of electrode assemblies 12 contained in the secondary battery 1 can be one or more, which can be adjusted according to demand.
  • secondary batteries may be assembled into a battery module.
  • the battery module may contain multiple secondary batteries, and the specific number may be adjusted according to the application and capacity of the battery module.
  • the plurality of secondary batteries may be arranged in sequence along the length direction of the battery module. Of course, they may also be arranged in any other manner. Further, the plurality of secondary batteries may be fixed by fasteners.
  • the battery module may further include a housing having a receiving space, and the plurality of secondary batteries are received in the receiving space.
  • the battery modules described above may also be assembled into a battery pack, and the number of battery modules contained in the battery pack may be adjusted according to the application and capacity of the battery pack.
  • the battery pack may include a battery box and a plurality of battery modules disposed in the battery box.
  • the battery box includes an upper box body and a lower box body, and the upper box body can be covered on the lower box body to form a closed space for accommodating the battery modules.
  • the plurality of battery modules can be arranged in the battery box in any manner.
  • the present application also provides an electric device, which includes at least one of the secondary battery, battery module, or battery pack.
  • the secondary battery, battery module, or battery pack can be used as a power source for the device, or as an energy storage unit for the device.
  • the device can be, but is not limited to, a mobile device, an electric vehicle, an electric train, a ship, a satellite, an energy storage system, etc.;
  • mobile devices may include but are not limited to at least one of mobile phones, laptops, etc.;
  • electric vehicles may include but are not limited to at least one of pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.
  • the device can select a secondary battery, a battery module or a battery pack according to its usage requirements.
  • Fig. 10 is an example of an electric device 2.
  • the electric device 2 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.
  • a battery pack or a battery module may be used.
  • the device may be a mobile phone, a tablet computer, a notebook computer, etc.
  • a device is usually required to be light and thin, and a secondary battery may be used as a power source.
  • the gas adsorption instrument of model Quantachrome (ASiQMVH002 5) was used to test the adsorption of N 2 by COF-1 material under standard atmospheric pressure (101 kPa), and the purity of the gas used in the test was 99.999%; the test steps were as follows: 100 mg of COF-1 was added to a quartz sample tube, and vacuum degassed at 120°C for 6 hours on the pretreatment station of the rapid specific surface area analyzer.
  • the gas adsorption instrument was used to conduct a gas adsorption experiment on COF-1. According to the obtained nitrogen adsorption curve, the pore size distribution (PSD) was calculated by the non-local density function theory (NLDFT).
  • NLDFT non-local density function theory
  • the pore size of the internal pores of MOF-1 was measured to be 0.34 nm.
  • the pore size of the internal pores of COF-2 was measured to be 4.8 nm.
  • the pore size of the internal pores of COF-3 was measured to be 0.3 nm.
  • the pore size of the internal pores of COF-4 was measured to be 0.8 nm.
  • the pore size of the internal pores of COF-5 was measured to be 0.97 nm.
  • the pore size of the internal pores of COF-6 was measured to be 2 nm.
  • the pore size of the internal pores of COF-7 was measured to be 5.8 nm.
  • the pore size of the internal pores of the obtained COF material is the same; the volume average particle size Dv50 of the finally obtained COF material can be further adjusted by controlling the reaction conditions such as temperature and time during the preparation of the COF material.
  • COF materials with the same internal pore size synthesized using the same monomers will be uniformly named in this application.
  • Polyvinylidene fluoride (as a polymer) was dissolved in N-methylpyrrolidone until it was clear, and a polymer solution with a mass percentage concentration of 5% was prepared; then COF-1 (as a barrier material) was added and dispersed at a high speed of 1000 rpm for 12 hours to obtain a slurry.
  • a PE membrane with a thickness of 7 ⁇ m and a pore size of 20 nm was spread flat in a Buchner funnel, and the slurry was added and filtered for 2 hours. Deionized water was then added to the Buchner funnel to wash away the residual slurry. The PE membrane was then removed from the Buchner funnel and dried in a vacuum drying oven at 80°C for 12 hours to obtain a diaphragm.
  • the preparation methods of the diaphragms in Examples 2-15, 18, and 22-34 are basically similar to the preparation method of the diaphragm in Example 1, and the main differences are: one or more of the type of barrier material, the volume average particle size Dv50 of the barrier material, the pore size of the internal pores of the barrier material, the thickness of the barrier layer, the ratio of the thickness of the barrier layer to the volume average particle size Dv50 of the barrier material, the air permeability of the barrier layer, the conductivity of the ion-conducting inorganic material, the type and/or weight average molecular weight and/or swelling degree of the polymer, the mass proportion of the polymer layer in the barrier layer, and the area proportion of the barrier material in the barrier layer are different. See Table 1 for details.
  • the preparation method of the diaphragm in Examples 16-17, Examples 19-21 and Examples 35-37 is different from the preparation method of the diaphragm in Example 1, and the type of barrier material, the volume average particle size Dv50 of the barrier material, the pore size of the internal pores of the barrier material, the thickness of the barrier layer, the ratio of the thickness of the barrier layer to the volume average particle size Dv50 of the barrier material, the air permeability of the barrier layer, the conductivity of the ion-conducting inorganic material, the type and/or weight average molecular weight and/or swelling degree of the polymer, the mass proportion of the polymer layer in the barrier layer, the area proportion of the barrier material in the barrier layer, the type of polymer, the type of the support layer, the pore size of the support layer and the thickness of the diaphragm are one or more of the following, see Table 1 for details. It should be noted that the thickness of the diaphragm in Examples 16-17, Examples 19-21 and Examples 36-37 refers to the thickness of the
  • the preparation method of the diaphragm in Example 16 is as follows: polyvinylidene fluoride (as a polymer) is dissolved in N-methylpyrrolidone until it is clear, LATP (as a barrier material) is added and dispersed at a high speed of 2000 rpm for 12 hours to obtain a slurry.
  • the slurry is coated on a PE film with a thickness of 7 ⁇ m (as a support layer) to form a barrier layer with a coating thickness of 2 ⁇ m; wherein the height of the scraper used for scraping is
  • the coating machine drives the scraper to move at a speed of 30mm/s.
  • the PE film loaded with the barrier layer is placed in a vacuum drying oven and dried at 80°C for 12 hours to obtain a once-treated barrier layer.
  • the PE film loaded with the once-treated barrier layer is spread flat in a Buchner funnel, a polyvinylidene fluoride solution with a mass percentage concentration of 5% is added, and filtered for 2 hours; then deionized water is added to the Buchner funnel to wash away the residual polyvinylidene fluoride solution; the PE film is removed from the Buchner funnel and placed in a vacuum drying oven at 80°C for 12 hours to obtain a diaphragm.
  • the preparation method of the diaphragm in Example 17 is as follows: polyvinylidene fluoride (as a polymer) is dissolved in N-methylpyrrolidone until it is clarified, and LLTO (as a barrier material) is added and dispersed at a high speed of 2000rmp for 12 hours to obtain a slurry.
  • the slurry is coated on a PE film (as a support layer) with a thickness of 7 ⁇ m to form a barrier layer, and the coating thickness is 2 ⁇ m; wherein, the height of the scraper used during the scraping is 5 ⁇ m, and the coating machine drives the scraper to move at a speed of 30mm/s.
  • the PE film loaded with the barrier layer is placed in a vacuum drying oven and dried at 80°C for 12 hours to obtain a once-treated barrier layer.
  • Spread the PE film loaded with the once-treated barrier layer in a Buchner funnel add a polyvinylidene fluoride solution with a mass percentage concentration of 5%, and filter for 2 hours; then add deionized water to the Buchner funnel to wash away the residual polyvinylidene fluoride solution; remove the PE film from the Buchner funnel, place it in a vacuum drying oven at 80°C and dry it for 12 hours to obtain a diaphragm.
  • the preparation method of the diaphragm in Example 19 is as follows: polyimide (as a polymer) is dissolved in N-methylpyrrolidone until it is clear, and a polymer solution with a mass percentage concentration of 5% is prepared. The polymer solution is scraped on a PE film (as a support layer) with a thickness of 7 ⁇ m, and the coating thickness is 1 ⁇ m to obtain a polymer layer loaded on the PE film; wherein, the height of the scraper used during scraping is 10 ⁇ m, and the coating machine drives the scraper to move at a speed of 30 mm/s.
  • LSPS as a barrier material
  • LSPS is evenly sprayed on the surface of the polymer layer, and the LSPS is embedded in the polymer layer by rolling, and then dried at 80°C in a vacuum drying oven for 12 hours to obtain a diaphragm.
  • the preparation method of the diaphragm in Example 20 is as follows: polyimide (as a polymer) is dissolved in N-methylpyrrolidone until it is clear, and a polymer solution with a mass percentage concentration of 5% is prepared. The polymer solution is scraped on a PE film (as a support layer) with a thickness of 7 ⁇ m, and the coating thickness is 1 ⁇ m to obtain a polymer layer loaded on the PE film; wherein, the height of the scraper used during scraping is 10 ⁇ m, and the coating machine drives the scraper to move at a speed of 30 mm/s.
  • LATP as a barrier material
  • LATP is evenly sprayed on the surface of the polymer layer, and LATP is embedded in the polymer layer by rolling, and then dried at 80°C in a vacuum drying oven for 12 hours to obtain a diaphragm.
  • the preparation method of the diaphragm in Example 21 is as follows: polyvinylidene fluoride (as a polymer) is dissolved in N-methylpyrrolidone until it is clarified, and a polymer solution with a mass percentage concentration of 5% is prepared. The polymer solution is scraped on a PE film (as a support layer) with a thickness of 7 ⁇ m, and the coating thickness is 1 ⁇ m to obtain a polymer layer loaded on the PE film; wherein, the height of the scraper used during scraping is 10 ⁇ m, and the coating machine drives the scraper to move at a speed of 30 mm/s.
  • LATP as a barrier material
  • LATP is evenly sprayed on the surface of the polymer layer, and LATP is embedded in the polymer layer by rolling, and then dried at 80°C in a vacuum drying oven for 12 hours to obtain a diaphragm.
  • the preparation method of the diaphragm in Example 35 is as follows: polyvinylidene fluoride (as a polymer) is dissolved in N-methylpyrrolidone until it is clear, and a polymer solution with a mass percentage concentration of 5% is prepared. The polymer solution is scraped on a glass plate with a coating thickness of 5 ⁇ m to obtain a polymer layer loaded on the glass plate; wherein, the height of the scraper used for scraping is 10 ⁇ m, and the coating machine drives the scraper to move at a speed of 30 mm/s.
  • COF-1 (as a barrier material) is evenly sprayed on the surface of the polymer layer, and the COF-1 material is embedded in the polymer layer by rolling, and then dried at 80°C in a vacuum drying oven for 12 hours, and the glass plate is removed to obtain a diaphragm.
  • the preparation method of the diaphragm in Example 36 is as follows: polyvinylidene fluoride (as a polymer) is dissolved in N-methylpyrrolidone until it is clear, and a polymer solution with a mass percentage concentration of 5% is prepared. The polymer solution is scraped on a PE film (as a support layer) with a thickness of 7 ⁇ m, and the coating thickness is 1 ⁇ m to obtain a polymer layer loaded on the PE film; wherein, the height of the scraper used during scraping is 10 ⁇ m, and the coating machine drives the scraper to move at a speed of 30 mm/s.
  • COF-1 (as a barrier material) is evenly sprayed on the surface of the polymer layer, and the COF-1 material is embedded in the polymer layer by rolling, and then dried at 80°C in a vacuum drying oven for 12 hours to obtain a diaphragm.
  • the preparation method of the diaphragm in Example 37 is as follows: polyvinylidene fluoride (as a polymer) is dissolved in N-methylpyrrolidone until it is clear, COF-1 (as a barrier material) is added and dispersed at a high speed of 2000rmp for 12 hours to obtain a slurry.
  • the slurry is coated on a PP film (as a support layer) with a thickness of 7 ⁇ m to form a barrier layer with a coating thickness of 2 ⁇ m; wherein the height of the scraper used during the coating is 5 ⁇ m, and the coating machine drives the scraper to move at a speed of 30mm/s.
  • the PP film loaded with the barrier layer is placed in a vacuum drying oven and dried at 80°C for 12 hours to obtain a once-treated barrier layer.
  • the PP film loaded with the once-treated barrier layer was spread flat in a Buchner funnel, and a polyvinylidene fluoride solution with a mass percentage concentration of 5% was added, and the film was filtered for 2 hours; then deionized water was added to the Buchner funnel to wash away the residual polyvinylidene fluoride solution; the PP film was removed from the Buchner funnel and placed in a vacuum drying oven to dry at 80°C for 12 hours to obtain a diaphragm.
  • Comparative Example 1 a common PP film is used as a separator.
  • the preparation method of the diaphragm in Comparative Example 2 is basically similar to the preparation method of the diaphragm in Example 1, with the main difference being that only 1/2 of the area of the PE membrane is filtered, and the rest is not processed.
  • the specific parameter settings are shown in Table 1.
  • the preparation method of the diaphragm in Comparative Example 3 is basically similar to the preparation method of the diaphragm in Example 1, and the main differences are: one or more of the following: the type of barrier material, the volume average particle size Dv50 of the barrier material, the pore size of the internal pores of the barrier material, the thickness of the barrier layer, the ratio of the thickness of the barrier layer to the volume average particle size Dv50 of the barrier material, the air permeability of the barrier layer, the conductivity of the ion-conducting inorganic material, the type and/or weight average molecular weight and/or swelling degree of the polymer, the mass proportion of the polymer layer in the barrier layer, and the area proportion of the barrier material in the barrier layer. For details, see Table 1.
  • volume average particle size Dv50 of the barrier material mentioned above is measured by Microtrac MRB S3500 series laser particle size analysis; the specific process is: take 2g of barrier material, add 20mL of deionized water, and ultrasonicate for 5 minutes to ensure that the sample is completely dispersed to obtain a dispersion, and then put the dispersion into the sample tank for testing to obtain the volume average particle size Dv50 of the barrier material.
  • the pore size of the internal pores of the barrier material COF-1 mentioned above is tested by the following method: take the COF-1 material to be tested, use a gas adsorption instrument of model Quantachrome (ASiQMVH002 5), test the adsorption amount of COF material to N 2 at standard atmospheric pressure (101kPa), and the purity of the gas used in the test is 99.999%; add 100mg COF material into a quartz sample tube, and degas at 120°C for 6h in a vacuum on the pretreatment station of a rapid specific surface area analyzer.
  • ASiQMVH002 5 gas adsorption instrument of model Quantachrome
  • NLDFT delocalized density functional theory model
  • the pore size of the internal pores of the barrier material MOF-1 mentioned above is tested by the following method: Take the MOF-1 material to be tested, use a gas adsorption instrument of model Quantachrome (ASiQMVH002 5), test the adsorption amount of MOF material to N 2 at standard atmospheric pressure (101kPa), and the purity of the gas used in the test is 99.999%; add 100mg MOF material to a quartz sample tube, and degas at 120°C for 6h in a vacuum on the pretreatment station of a rapid specific surface area analyzer.
  • ASiQMVH002 5 gas adsorption instrument of model Quantachrome
  • NLDFT delocalized density functional theory model
  • the conductivity of the barrier materials LLZO, LLTO, LATP, LAGP and LSPS mentioned above was measured by the following method: the ion-conducting inorganic material was made into a solid electrolyte ceramic sample, and the solid electrolyte ceramic sample was subjected to an AC impedance test by a CHI660E electrochemical workstation. The sample with conductive silver paste as an electrode was clamped with a test clip (i.e., silver was plated on both sides of the electrolyte disc), and the test frequency range was 10 ⁇ 6Hz-0.1Hz. The total impedance value was obtained by analyzing the impedance spectrum obtained by the test, and then the corresponding total ionic conductivity was calculated.
  • ⁇ is the ionic conductivity, in mS ⁇ cm -1
  • d is the thickness of the electrolyte sheet, in cm
  • R is the impedance value of the electrolyte sheet measured by the electrochemical workstation, in ohms
  • P is the bottom area of the electrolyte sheet, in cm 2 .
  • the area ratio of the barrier material mentioned above in the barrier layer is tested by the following method: a SEM image of the barrier layer is taken using a scanning electron microscope, and the total area of the barrier material and the area of the barrier layer are calculated based on the SEM image of the barrier layer; the area ratio of the barrier material in the barrier layer is calculated according to the formula: total area of the barrier material/area of the barrier layer.
  • the mass proportion of the above-mentioned polymer layer in the barrier layer is tested by the following method: Use a thermogravimetric-differential scanning calorimeter to analyze the components of the barrier layer: Take 15-25 mg of the barrier layer, place it in an alumina crucible, use nitrogen as a protective gas, preheat at 25°C for 30 minutes, and then heat to 600°C at a rate of 2°C/10min. Determine the content of each component based on the weight change and heat change.
  • the test method for the air permeability of the barrier layer mentioned above is: spread the barrier layer flat, select a flat and oil-free position, place it on the air outlet of the air compressor, and tighten it; after the barrier layer is fixed at the work station, use the gravity of the cylinder floating on the liquid to compress the air in the cylinder. As the air passes through the sample, the cylinder will fall steadily. Test the time required for a certain volume of air to pass through the sample, and calculate the air permeability based on this. Among them, the volume of the air column is 100CC; the test area is 6.45cm2 ; the sample area is> 6cm ⁇ 6cm.
  • the average pore size of the support layer pores mentioned above was tested by the following method: the pore size of the diaphragm was tested using the PMI multifunctional pore size analyzer from PMI, USA; the sample to be tested was cut into discs with a diameter of 0.5 cm, immersed in the infiltration liquid for 10 minutes, and transferred to the fixture with tweezers; the pressure range was set to 0-500PSI for pore size testing.
  • the thickness of the above mentioned diaphragm is measured by the following method: calibrate the micrometer, then place the diaphragm between the double anvils, gently rotate the sleeve until a sound is heard, and read the thickness of the diaphragm.
  • the thickness of the barrier layer mentioned above is measured by the following method: calibrate the micrometer, then place the diaphragm between the double anvils, gently rotate the sleeve until a sound is heard, and read the reading to record the thickness of the diaphragm.
  • the thickness of the barrier layer mentioned above is tested by the following method: first calibrate the micrometer, then place the diaphragm between the double anvils, gently rotate the sleeve until a sound is heard, and read and record the thickness of the diaphragm; remove the diaphragm, remove the barrier layer to obtain the support layer, repeat the above measurement process, and measure the thickness of the support layer; subtract the thickness of the support layer from the thickness of the diaphragm to obtain the thickness of the barrier layer.
  • the weight average molecular weight of the above-mentioned polymers is measured by gel permeation chromatography (GPC).
  • the diaphragm flat, select a flat and oil-free position, place it on the air outlet of the air compressor, and tighten it; after the diaphragm is fixed in the work position, use the gravity of the cylinder floating on the liquid to compress the air in the cylinder. As the air passes through the sample, the cylinder will fall steadily. Measure the time required for a certain volume of air to pass through the sample, and calculate the air permeability based on this. Among them, the volume of the air column is 100CC; the test area is 6.45cm2 ; the sample area is>6cm ⁇ 6cm. The results are detailed in Table 2.
  • LNMO LiNi 0.5 Mn 1.5 O 4 , as the positive electrode active material
  • conductive carbon black as the conductive agent
  • polyvinylidene fluoride as the binder
  • N-methylpyrrolidone was added and stirred to disperse into a positive electrode slurry.
  • the positive electrode slurry was coated on both sides of the aluminum foil, dried, cold pressed and cut to obtain a positive electrode sheet.
  • the unit surface density of the positive electrode powder coated on one side was 0.02g/cm 2 .
  • Artificial graphite (as negative electrode active material), conductive carbon black (as conductive agent), styrene-butadiene rubber (as binder) and sodium carboxymethyl cellulose (as thickener) were mixed in a mass ratio of 96:1:1:2, and then deionized water was added and stirred to disperse into negative electrode slurry.
  • the negative electrode slurry was evenly coated on one side of the copper foil, dried, cold pressed and cut to obtain a negative electrode sheet.
  • the negative electrode powder had a single-side coating unit area density of 0.008 g/ cm2 .
  • Preparation of positive electrode electrolyte In a glove box filled with argon (water content ⁇ 10ppm, oxygen content ⁇ 10ppm), add 1wt% of vinylene sulfate and 1wt% of propane sultone to methyl trifluoroethyl carbonate (FEMC), mix thoroughly, and finally add lithium hexafluorophosphate ( LiPF6 ) to the mixed solution until the molar concentration of LiPF6 is 1mol/L to prepare the positive electrode electrolyte.
  • argon water content ⁇ 10ppm, oxygen content ⁇ 10ppm
  • FEMC methyl trifluoroethyl carbonate
  • LiPF6 lithium hexafluorophosphate
  • the positive electrode sheet, the separator and the negative electrode sheet are stacked in order, so that the separator is between the positive and negative electrode sheets to play a role of isolation, and the three are placed in an aluminum-plastic bag with the same length and width as the separator, and the other three sides of the aluminum-plastic bag except before the opening are heat-sealed together with the separator, and the separator and the aluminum-plastic bag form a dense positive electrode chamber and a negative electrode chamber, and the positive electrode chamber side is injected with a positive electrode electrolyte, and the negative electrode chamber side is injected with a negative electrode electrolyte, and the battery cell is sealed, and then the battery cell is placed in a battery casing, formed, and left to stand to obtain a secondary battery.
  • the secondary batteries in the above embodiments and comparative examples are charged to 4.9V at a constant current of 0.1C, and then charged to a current of 0.05C at a constant voltage of 4.9V; after standing for 5 minutes, the secondary batteries are discharged to 3.5V at a constant current of 0.1C.
  • This is a charge and discharge cycle process, and the discharge capacity at this time is the initial discharge capacity of the secondary battery.
  • the secondary battery is charged and discharged cyclically according to the above method until the discharge capacity after the cycle decays to 80% of the initial discharge capacity, and the test is terminated, and the number of cycles of the secondary battery at this time is recorded.
  • the secondary batteries in the above embodiments and comparative examples are respectively charged to 4.9V at a constant current of 0.1C, and then charged to a current of 0.05C at a constant voltage of 4.9V, at which time the secondary batteries are in a fully charged state.
  • the fully charged secondary batteries are stored in a 25°C environment, taken out every 5 days, and discharged to 3.5V at a constant current of 0.1C to obtain the discharge capacity after storage for a period of time; then the secondary batteries are fully charged in the above manner and stored again in a 25°C environment until the discharge capacity of the secondary batteries after storage decays to 70% of the initial discharge capacity, the test is terminated, and the total number of storage days of the secondary batteries is recorded.
  • the air permeability of the barrier layer is ⁇ 300s/100mL, and the barrier layer can greatly inhibit the penetration of solvents, additives and by-products in the electrolyte, thereby eliminating the battery capacity attenuation caused by the interaction between the positive and negative electrodes.
  • Examples 1-6 lie mainly in the different ratios of the barrier layer thickness and the volume average particle size Dv50 of the barrier material, with the ratio of the two being the largest in Example 6.
  • the number of cycles and storage days in Example 6 are significantly reduced, and the cycle impedance is significantly increased. It is speculated that when d1/D is too large, the barrier material particles may be stacked too closely, and the barrier material particles may have too many contact surfaces with each other, which may slow down the transmission speed of lithium ions through the barrier material.
  • Example 3 and Examples 7-12 The difference between Example 3 and Examples 7-12 is that the pores inside the barrier material have different pore sizes, and the pore size of the pores inside the barrier material is the largest in Example 12. Compared with Example 3 and Examples 7-11, the number of cycles and storage days in Example 12 are significantly reduced. It is speculated that this may be because when the pore size of the barrier material is too large, the barrier effect of the diaphragm is weakened, which may allow some substances other than lithium ions in the electrolyte to penetrate the diaphragm.
  • Example 15 Compared with Example 14, Examples 16-17, and Examples 19-21, the cycle impedance of the secondary battery in Example 15 is significantly increased; it is speculated that this may be due to the poor conductivity of LLZO, which leads to the increase in the impedance of the secondary battery.
  • Example 18 Compared with Example 14, Examples 16-17 and Examples 19-21, the cycle impedance of the secondary battery in Example 18 is significantly increased; it is speculated that this may be due to the excessive ratio of the barrier layer thickness to the barrier material volume average particle size Dv50, which leads to a significant increase in the impedance of the secondary battery.
  • Example 3 and Examples 24-30 The difference between Example 3 and Examples 24-30 is that the area ratio of the barrier material in the barrier layer and the mass ratio of the polymer layer in the barrier layer are different, and the area ratio of the barrier material in the barrier layer is the smallest in Example 28.
  • Example 3 Examples 24-27 and Examples 29-30 the number of cycles of the secondary battery in Example 28 is significantly reduced and the impedance is significantly increased; it is speculated that this may be because when the unit area ratio of the barrier material in the barrier layer is too low, it may lead to a reduction in lithium ion transmission channels, deteriorate the battery impedance, and reduce its cycle performance and storage performance.
  • Example 3 and Examples 31-34 The difference between Example 3 and Examples 31-34 is that the weight average molecular weight of the polymer is different.
  • the weight average molecular weight of the polymer in Example 31 is the smallest.
  • the number of cycles and storage days in Example 31 are significantly reduced; it is speculated that when the weight average molecular weight of the polymer is too low, the density of the barrier layer formed is poor, and the barrier effect of the barrier layer may be weakened, and some substances other than lithium ions in the electrolyte can also penetrate the diaphragm.
  • Example 1 when the air permeability of the barrier layer is lower than 300 s/100 mL, the barrier layer may weaken the interaction inhibition effect between the positive electrode and the negative electrode.

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Abstract

本申请涉及一种隔膜、二次电池及用电装置。其中的隔膜，包括阻隔层，阻隔层包括聚合物层和至少部分嵌入聚合物层中的阻隔材料；其中，阻隔材料包括微介孔材料和导离子无机材料中的一种或多种；阻隔材料的体积平均粒径Dv50记为D，阻隔层的厚度记为d1，阻隔材料的体积平均粒径Dv50和阻隔层的厚度满足：0.2≤d1/D≤1000；阻隔层的透气度≥300s/100mL。

Description

隔膜、二次电池及用电装置 技术领域
本申请属于二次电池技术领域，具体涉及一种隔膜、二次电池及用电装置。
背景技术
二次电池因具有重量轻、无污染、无记忆效应等突出特点，被广泛应用于各类消费类电子产品和电动车辆中。随着新能源行业的不断发展，用户对二次电池提出了更高的使用需求。例如，高能量密度、更长循环寿命、更具环境适应性等；然后高能量密度设计、长循环、高温等条件下，往往会引起电极的严重破坏，引起电池容量衰减。
发明内容
鉴于背景技术中存在的技术问题，本申请提供一种隔膜、二次电池及用电装置，旨在减少电极的破坏，降低电池容量衰减。
为了实现上述目的，本申请的第一方面提供一种隔膜，包括阻隔层，所述阻隔层包括聚合物层和至少部分嵌入所述聚合物层中的阻隔材料；
其中，所述阻隔材料包括微介孔材料和导离子无机材料中的一种或多种；所述阻隔材料的体积平均粒径Dv50记为D，所述阻隔层的厚度记为d1，所述阻隔材料的体积平均粒径Dv50和所述阻隔层的厚度满足：0.2≤d1/D≤1000；
所述阻隔层的透气度≥300s/100mL。
相对于现有技术，本申请至少包括如下所述的有益效果：
本申请的隔膜，其包括阻隔层，阻隔层包括聚合物层和阻隔材料，通过调控阻隔材料的体积平均粒径Dv50以及阻隔层厚度，阻隔层的透气度≥300s/100mL，气体透过阻隔层的难度较大，表明聚合物层中大部分孔径已被阻隔材料填充；相较于气体，正极电解液和负极电解液中的溶剂、添加剂以及界面反应副产物通过阻隔层的难度更大，仅有锂离子可通过阻隔材料穿透阻隔层，大幅度抑制了电解液中溶剂、添加剂和副产物穿过阻隔层，消除正极和负极交互引起的电池容量衰减。
在本申请任意实施方式中，所述阻隔层的透气度≥500s/100mL；可选地，所述阻隔层的透气度≥800s/100mL。
在本申请任意实施方式中，所述阻隔材料的体积平均粒径Dv50和所述阻隔层的厚度满足：1≤d1/D≤500；可选为1≤d1/D≤300。
在本申请任意实施方式中，所述阻隔材料的体积平均粒径Dv50满足：0.005μm≤D≤10μm；可选为0.007μm≤D≤5μm；进一步可选为0.01μm≤D≤1μm。
在本申请任意实施方式中，所述阻隔层的厚度满足：0.007μm≤d1≤50μm；可选为0.2μm≤d1≤15μm。
在本申请任意实施方式中，所述微介孔材料包括共价有机框架材料和金属有机骨架材料中的一种或多种；
可选地，聚合形成所述共价有机框架材料的单体之间的连接基团包括环硼氧基、-C＝N-、三嗪基团、-C＝N-N＝C-、-C＝C-、-CO-NH-、-C＝N-NH-CO-和咪唑基团中的一种或几种。
在本申请任意实施方式中，所述导离子无机材料包括LLZO、LLTO、LATP、LAGP、LSPS，以及上述物质的包覆物、掺杂物和/或带有包覆层的掺杂物中的一种或多种。
在本申请任意实施方式中，所述微介孔材料的内部孔隙的孔径记为d2，所述微介孔材料的内部孔隙的孔径满足：0.04nm≤d2≤5nm；可选为0.3nm≤d2≤2nm。
在本申请任意实施方式中，在25℃时所述导离子无机材料的电导率≥0.0001mS·cm-1；
可选地，在25℃时所述导离子无机材料的电导率≥0.001mS·cm-1；
进一步可选地，在25℃时所述导离子无机材料的电导率≥0.01mS·cm-1。
在本申请任意实施方式中，所述阻隔材料在所述阻隔层中的面积占比为30％-99％；可选为50％-99％；进一步可选为70％-99％。
在本申请任意实施方式中，所述聚合物层具有如下(1)-(3)项特征中的至少一项：
(1)所述聚合物层包括溶胀度≤10％的聚合物；
可选地，所述聚合物包括聚乙烯、聚丙烯、聚酰亚胺和聚偏二氟乙烯中的一种或多种；
(2)所述聚合物层在所述阻隔层中的质量占比≤50％；
可选地，所述聚合物层在所述阻隔层中的质量占为2％-30％；进一步可选为5％-15％；
(3)所述聚合物层包括重均分子量为1W-200W的聚合物；
可选地，所述聚合物层包括重均分子量为2W-150W的聚合物；
进一步可选地，所述聚合物层包括重均分子量为10W-100W的聚合物。
在本申请任意实施方式中，所述隔膜还包括支撑层，所述阻隔层位于所述支撑层的至少一侧。
在本申请任意实施方式中，所述支撑层具有如下(1)-(3)项特征中的至少一项：
(1)所述支撑层具有孔隙，所述支撑层的孔隙的平均孔径为20nm-1000nm；可选为100nm-500nm；
(2)所述支撑层的原料包括聚乙烯、聚丙烯、聚酰亚胺和聚偏二氟乙烯中的一种或多种。
在本申请任意实施方式中，所述隔膜的厚度为2μm-12μm；可选为3μm-10μm；进一步可选为5μm-7μm。
在本申请任意实施方式中，所述隔膜具有下述特征中的至少一项：
(1)所述隔膜的透气度≥300s/100mL；可选地，所述隔膜的透气度≥500s/100mL；进一步可选地，所述隔膜的透气度≥800s/100mL；
(2)所述隔膜的拉伸强度≥1000MPa；可选地，所述隔膜的拉伸强度≥1200MPa；进一步可选地，所述隔膜的拉伸强度≥1500MPa。
本申请的第二方面提供了一种二次电池，包括正极极片、负极极片、正极电解液、负极电解液以及如本申请第一方面所述的隔离膜；
所述隔离膜位于所述正极极片和所述负极极片之间，所述正极电解液位于所述正极极片和所述隔离膜之间，所述负极电解液位于所述负极极片和所述隔离膜之间；所述正极电解液和所述负极电解液中含有的溶剂、锂盐和添加剂中的一项或多项是不同的。
在本申请任意实施方式中，所述正极电解液的溶剂和所述负极电解液的溶剂不同；
可选地，所述正极电解液的溶剂包括碳酸酯类溶剂、氟代碳酸酯类溶剂、氟代羧酸酯类溶剂、砜类溶剂、氟代砜类溶剂、磷酸酯类溶剂、硼酸酯类溶剂和腈类溶剂中的一种或多种；
可选地，所述负极电解液的溶剂包括碳酸酯类溶剂、羧酸酯类溶剂、醚类溶剂、氟代羧酸酯类溶剂和氟代碳酸酯类溶剂中的一种或多种。
在本申请任意实施方式中，所述氟代碳酸酯类溶剂包括甲基三氟乙基碳酸酯、二(三氟甲基)碳酸酯、二(三氟乙基)碳酸酯、4-三氟甲基碳酸乙烯酯、双氟代碳酸乙烯酯、三氟甲基三氟乙基碳酸酯、三氟丙基碳酸酯和2,2-二氟乙基甲基碳酸酯中的一种或多种；
所述氟代羧酸酯类溶剂包括3,3,3-三氟乙酸三氟乙酯、乙酸2,2-二氟乙酯、二氟乙酸乙酯和乙酸2,2,2-三氟乙酯中的一种或多种；
所述砜类溶剂包括环丁砜、二甲基砜、二乙基砜、甲基乙基砜、甲基异丙基砜、二甲基亚砜、二乙基亚砜和甲基乙基亚砜中的一种或多种；
所述氟代砜类溶剂包括甲基三氟甲基砜、乙基三氟甲基砜、丙基三氟甲基砜、甲基三氟乙基砜、甲基三氟丙基砜、1,1,2,2-四氟丙基甲基砜、三氟甲基异丙基砜和甲基六氟异丙基砜中的一种或多种；
所述磷酸酯类溶剂包括磷酸三甲酯、磷酸三乙酯、磷酸三丙酯、磷酸异丙基酯、磷酸三(六氟异丙基)酯和磷酸三(2,2,2-三氟乙基)酯中的一种或多种；
所述硼酸酯类溶剂包括硼酸三甲酯、硼酸三乙酯、硼酸三(六氟异丙基)酯和硼酸三(2,2,2-三氟乙基)酯中的一种或多种；
所述腈类溶剂包括乙腈、琥珀腈、丁二腈、戊二腈、己二腈、1,4-二氰基-2-丁烯、1,3,6-己烷三腈、乙二醇双丙腈醚和1,2,3-三氰乙氧基中的一种或多种；
所述碳酸酯类溶剂包括碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯和碳酸乙烯酯中的一种或多种；
所述羧酸酯类溶剂包括甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯和丙酸丙酯中的一种或多种；
所述醚类溶剂包括1,2-二甲氧基乙烷、四乙醇二甲醚、γ-丁内酯和四氢呋喃中的一种或多种。
在本申请任意实施方式中，所述正极电解液的锂盐和所述负极电解液的锂盐不同；
可选地，所述正极电解液的锂盐包括六氟磷酸锂、四氟硼酸锂、双氟磺酰亚胺锂和二草酸硼酸锂中的一种或多种；
可选地，所述负极电解液的锂盐包括六氟磷酸锂、四氟硼酸锂、双氟磺酰亚胺锂和二草酸硼酸 锂中的一种或多种。
本申请的第三方面提供了一种用电装置，包括本申请第二方面的二次电池。
附图说明
为了更清楚地说明本申请的技术方案，下面将对本申请中所使用的附图作简单介绍。显而易见地，下面所描述的附图仅仅是本申请的一些实施方式，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1是本申请一实施例提供的COF-1结构示意图。
图2是本申请一实施例提供的COF-2结构示意图。
图3是本申请一实施例提供的COF-3结构示意图。
图4是本申请一实施例提供的COF-4结构示意图。
图5是本申请一实施例提供的COF-5结构示意图。
图6是本申请一实施例提供的COF-6结构示意图。
图7是本申请一实施例提供的COF-7结构示意图。
图8是本申请一实施方式的二次电池的示意图。
图9是图8所示的本申请一实施方式的二次电池的分解图。
图10是本申请一实施方式的二次电池用作电源的用电装置的示意图。
附图标记说明：
1二次电池；11壳体；12电极组件；13盖板；2用电装置。
具体实施方式
下面结合具体实施方式，进一步阐述本申请。应理解，这些具体实施方式仅用于说明本申请而不用于限制本申请的范围。
为了简明，本文仅具体地公开了一些数值范围。然而，任意下限可以与任意上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，每个单独公开的点或单个数值自身可以作为下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包括本数，“一种或几种”中“几种”的含义是两种及两种以上。
在本文的描述中，除非另有说明，术语“或(or)”是包括性的。也就是说，短语“A或(or)B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。除非另有说明，本申请中使用的术语具有本领域技术人员通常所理解的公知含义。除非另有说明，本申请中提到的各参数的数值可以用本领域常用的各种测量方法进行测量(例如，可以按照在本申请的实施例中给出的方法进行测试)。
目前，二次电池在高能量密度设计、长循环、高温等条件下，往往造成电极的严重破坏，引起电池容量衰减。本申请的技术人员分析发现主要是在高能量密度设计、长循环、高温等条件下，电池的正极、负极、电解液的反应不断加剧，产生复杂多样的副产物，副产物借助电解液传播，在正极和负极之间相互扩散，在另一侧进一步反应，造成电极的破坏，引起电池容量衰减。
此外，一些电解液成分对正极和负极的兼容性往往不同，可能在一侧起正向作用，在另一侧则具有副作用，为了平衡二者，电解液逐渐走向复杂化设计，限制了电池的个性化设计，同时也增加了电池的成本；为了兼顾正极和负极，电解液可选择的溶剂、锂盐十分有限，无法发挥各电解液组分的优势。
本申请提供的隔膜，包括阻隔层，阻隔层包括聚合物层和至少部分嵌入聚合物层中的阻隔材料；其中，阻隔材料包括微介孔材料和导离子无机材料中的一种或多种；阻隔材料的体积平均粒径Dv50记为D，阻隔层的厚度记为d1，阻隔材料的体积平均粒径Dv50和阻隔层的厚度满足：0.2≤d1/D≤1000；阻隔层的透气度≥300s/100mL。
需要说明的是，本申请提及的阻隔材料仅允许锂离子通过，而电解液中的溶剂、添加剂以及界面反应副产物无法通过。阻隔材料可以全部嵌入聚合物层中，此时阻隔层的厚度与聚合物层的厚度相同；也可以部分嵌入聚合物层中，部分暴露在聚合物层外，此时阻隔层的厚度为聚合物层的厚度与暴露在聚合物层外的阻隔材料的厚度之和。聚合物层具有类似基材的作用，可提供容纳阻隔材料的空间。阻隔层中可以包括一种阻隔材料，也可以同时包括两种或两种以上阻隔材料；阻隔层中包括两种或两种以上阻隔材料时，阻隔材料可以均为微介孔材料，也可以均为导离子无机材料，还可以同时包括微介孔材料和导离子无机材料。微介孔材料是指具有微孔结构和/或介孔结构的材料；微孔是指孔径小于2nm的孔，介孔是指孔径为2nm-50nm的孔。导离子无机材料是指可以导通金属离子的材料。
本申请的隔膜，其包括阻隔层，阻隔层包括聚合物层和阻隔材料，通过调控阻隔材料的体积平均粒径Dv50以及阻隔层厚度，阻隔层的透气度≥300s/100mL，气体透过阻隔层的难度较大，表明聚合物层中大部分孔径已被阻隔材料填充；相较于气体，正极电解液和负极电解液中的溶剂、添加剂以及界面反应副产物通过阻隔层的难度更大，仅有锂离子可通过阻隔材料穿透阻隔层，大幅度抑制了电解液中溶剂、添加剂和副产物穿过阻隔层，消除正极和负极交互引起的电池容量衰减。
上述提及的阻隔材料的体积平均粒径Dv50和阻隔层的厚度满足：0.2≤d1/D≤1000；例如，可以为0.2≤d1/D≤900、0.2≤d1/D≤800、0.2≤d1/D≤700、0.2≤d1/D≤600、0.2≤d1/D≤500、0.2≤d1/D≤400、0.2≤d1/D≤300、0.2≤d1/D≤200、0.2≤d1/D≤100或0.2≤d1/D≤50等。d1/D小于上述范围时，阻隔层容易破裂；d1/D大于上述范围时，有可能会导致阻隔材料颗粒之间的堆叠过于紧密，阻隔材料颗粒相互之间接触面过多，可能会使锂离子经由阻隔材料的传输速度减慢，恶化电池阻抗。作为示例，d1/D可以为0.2、1、50、100、150、200、250、300、350、400、450、500、600、700、800、900或1000等。
上述提及的阻隔材料的Dv50指的是在体积分布中50％阻隔材料所对应的粒度尺寸。作为示例，可采用下述方法测试得到：采用激光粒度分析；将阻隔层样品置于去离子水中，超声5min，确保样品完全分散，然后将分散液置于样品槽后进行测试，得到阻隔材料的体积平均粒径Dv50。可选地，阻隔层的质量可以为0.05g-2g，去离子水的体积为10mL-20mL。
作为示例，上述提及的阻隔层的厚度可采用下述方法测得：首先校准千分尺，然后将阻隔层样品置于双砧之间，轻轻旋转套筒至出现响声，读数记录阻隔层厚度。
上述提及的阻隔层的透气度≥300s/100mL；可选地，阻隔层的透气度为300s/100mL-5000s/100mL；例如，可以为300s/100mL-4500s/100mL、300s/100mL-4000s/100mL、300s/100mL-3500s/100mL、300s/100mL-3000s/100mL、300s/100mL-2500s/100mL、300s/100mL-2000s/100mL、300s/100mL-1900s/100mL、300s/100mL-1800s/100mL、300s/100mL-1700s/100mL、300s/100mL-1600s/100mL、300s/100mL-1500s/100mL、300s/100mL-1400s/100mL、 300s/100mL-1300s/100mL、300s/100mL-1200s/100mL、300s/100mL-1100s/100mL或300s/100mL-1000s/100mL等。阻隔层的透气度越大，阻隔效果越好。作为示例，阻隔层的透气度可以为300s/100mL、400s/100mL、500s/100mL、600s/100mL、700s/100mL、800s/100mL、900s/100mL、1000s/100mL、1100s/100mL、1200s/100mL、1300s/100mL、1400s/100mL、1500s/100mL、1600s/100mL、1700s/100mL、1800s/100mL、1900s/100mL、2000s/100mL、2300s/100mL、2500s/100mL、2800s/100mL、3000s/100mL、3300s/100mL、3500s/100mL、3700s/100mL、4000s/100mL、4300s/100mL、4500s/100mL、4800s/100mL或5000s/100mL等。
作为示例，上述提及的隔膜的透气度可采用如下方法测试得到：将阻隔层平展，选取平整无油污的位置，放置在空气压缩筒出气口，旋紧固定；阻隔层固定在工位后，用浮动在液体上的圆筒的自身重力来压缩筒内空气。随着空气通过试样，圆筒便会平稳下落。测量一定体积的空气，通过试样所需的时间，并按此计算透气度。其中，空气柱体积为100CC；测试面积为6.45cm2；样品面积＞6cm×6cm。
本申请的发明人经深入研究发现，当本申请的隔膜在满足上述设计条件的基础上，若还可选地满足下述条件中的一个或几个时，可以进一步提升二次电池的存储性能和循环性能。
在一些实施方式中，阻隔层的透气度≥500s/100mL；可选地，阻隔层的透气度≥800s/100mL。
在一些实施方式中，阻隔层的透气度为500s/100mL-5000s/100mL；可选地，阻隔层的透气度为800s/100mL-5000s/100mL。
在一些实施方式中，阻隔材料的体积平均粒径Dv50和阻隔层的厚度满足：1≤d1/D≤500；可选为1≤d1/D≤300。
在一些实施方式中，阻隔材料的体积平均粒径Dv50满足：0.005μm≤D≤10μm；例如，可以为0.005μm≤D≤9μm、0.005μm≤D≤8μm、0.005μm≤D≤7μm、0.005μm≤D≤6μm、0.005μm≤D≤5μm、0.005μm≤D≤4μm、0.005μm≤D≤3μm、0.005μm≤D≤2μm、0.005μm≤D≤1μm、0.005μm≤D≤0.5μm、0.005μm≤D≤0.1μm、0.005μm≤D≤0.01μm等。阻隔材料的体积平均粒径Dv50低于上述范围内时，有可能会导致阻隔材料颗粒之间的堆叠过于紧密，阻隔材料颗粒相互之间接触面过多，可能会使锂离子经由阻隔材料的传输速度减慢。阻隔材料的体积平均粒径Dv50在上述范围内时，锂离子通过阻隔材料穿透隔膜的可能性大，且可降低阻隔材料颗粒相互之间的接触面，减少对锂离子传输速度的影响。作为示例，阻隔材料的体积平均粒径Dv50可以为0.005μm、0.01μm、0.05μm、0.1μm、0.5μm、1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm或10μm等。可选地，阻隔材料的体积平均粒径Dv50满足：0.007μm≤D≤5μm。进一步可选地，阻隔材料的体积平均粒径Dv50满足：0.01μm≤D≤1μm。
在一些实施方式中，阻隔层的厚度满足：0.007μm≤d1≤50μm；例如，可以为0.007μm≤L≤45μm、0.01μm≤L≤40μm、0.05μm≤L≤35μm、0.1μm≤L≤30μm、0.1μm≤L≤25μm、0.1μm≤L≤20μm、0.1μm≤L≤15μm、0.1μm≤L≤10μm、0.1μm≤L≤5μm或0.1μm≤L≤1μm等。阻隔层的厚度高于上述范围内时，增加了离子传输路径，可能会使电池阻抗恶化，还可能会使电池体积能量密度恶化；阻隔层的厚度低于上述范围内时，增大了加工制备的难度；阻隔层的厚度在上述范围内时，既具有优异的导离子性，又具有较佳的阻隔效果，同时加工难度较低。例如，阻隔层的厚度可以为0.007μm、0.01μm、0.05μm、0.1μm、0.5μm、1μm、3μm、5μm、7μm、10μm、15μm、20μm、30μm、40μm或50μm等。可选地，阻隔层的厚度满足：0.2μm≤d1≤15μm。
在一些实施方式中，微介孔材料包括共价有机框架材料和金属有机骨架材料中的一种或多种。
需要说明的是，共价有机框架材料(以下简称COF材料)是一类结晶性的有机多孔材料，基于可逆化学反应将功能单元以共价键的形式连接成高度有序的二维层叠层结构或特定的三维拓扑结构。COF材料可以为多个单体的均聚物，也可以为多个单体的共聚物。
可理解地，形成COF材料的单体种类和单体具有的可参与聚合物反应官能团数量，决定了COF材料的构型，也决定了COF材料的内部孔隙的孔径；COF材料的内部孔隙的孔径越大，越有利于锂离子传输，COF材料的内部孔隙的孔径越小，抑制电解液中除锂离子之外的其他物质通过的效果越好。
需要说明的是，电解液中其他物质包括溶剂、添加剂以及二次电池的正极、负极、电解液等发生反应时产生的复杂多样的副产物。
可选地，聚合形成共价有机框架材料的单体之间的连接基团包括环硼氧基、-C＝N-、三 嗪基团、-C＝N-N＝C-、-C＝C-、-CO-NH-、-C＝N-NH-CO-和咪唑基团中的一种或几种。
上述提及的连接基团指共价有机框架材料中相邻的两个单体单元之间的连接基团。
需要说明的是，上述提及的环硼氧基的结构式为上述提及的三嗪基团的结构式为上述提及的咪唑基团的结构式为上述提及的-CO-NH-基团的结构式为上述提及的-C＝N-NH-CO-基团的结构式为
作为示例，上述提及的聚合形成COF材料的单体以及单体之间的连接基团可采用如下方法测定得到：取阻隔层置于NMP或水中浸泡24h；过滤溶解的材料粉体，并重新放入新的NMP溶剂或水中浸泡2h，之后再超声2h以使颗粒充分分散，重复清洗超声过程3次以上，最后得到COF材料，并放入真空干燥箱80℃干燥24h。采用X射线粉末衍射仪测定其X射线衍射谱，采用红外光谱仪和核磁共振波谱仪测定其傅里叶红外光谱和核磁共振波谱，由隔离膜的X射线衍射谱、傅里叶红外光谱和核磁共振波谱结合判断隔离膜中含有的COF材料的结构，进而确定形成COF材料的单体种类及单体之间的连接基团。其中，X射线粉末衍射仪可采用Science Ultima IV型X射线粉末衍射仪，红外光谱仪可采用型号为Bruker ALPHA、波长范围400cm-1～4000cm-1的红外光谱仪，核磁共振波谱仪可采用Bruker AV III 400核磁共振波谱仪。
金属有机骨架材料(以下简称MOF材料)是一类由无机金属中心与桥连的有机配体通过自组装相互连接，形成的一类具有周期性网络结构的晶态多孔材料。其中，无机金属中心可以为金属离子和金属簇中的一种或多种。
在一些实施方式中，导离子无机材料包括LLZO、LLTO、LATP、LAGP、LSPS，以及上述物质的包覆物、掺杂物和/或带有包覆层的掺杂物中的一种或多种。
需要说明的是，LLZO为锂镧锆氧固态电解质，LLTO为锂镧钛氧固态电解质，LATP为磷酸钛铝锂固态电解质，LAGP为Li1.5Al0.5Ge1.5(PO4)3，LSPS为硫化物固态电解质。LLZO、LLTO、LATP、LAGP具有合成的电导率和较好的稳定性，LSPS具有显著高的电导率，导离子性能好，上述导离子无机材料均能导通锂离子以使其穿透阻隔层。
包覆物是指在上述提及的各材料的至少部分外表面形成包覆层后得到的物质。掺杂物是指向上述提及的各材料中添加过渡金属元素和非过渡金属元素中的一种或多种后形成的物质。带有包覆层的掺杂物是指在上述提及的各材料的掺杂物的至少部分外表面形成包覆层后得到的物质。
在一些实施方式中，微介孔材料的内部孔隙的孔径记为d2，微介孔材料的内部孔隙的孔径满足：0.04nm≤d2≤5nm；例如，可以为0.04nm≤d2≤4.5nm、0.1nm≤d2≤4nm、0.1nm≤d2≤3nm、0.1nm≤d2≤2nm、0.1nm≤d2≤1nm或0.1nm≤d2≤0.5nm等。微介孔材料的内部孔隙的孔径满足上述范围时，可仅容许脱溶剂化后的锂离子经由微介孔材料的内部孔隙穿透隔膜，阻止电解液中除锂离子之外的其他物质穿透隔膜，抑制正极和负极之间的交互。例如，微介孔材料的内部孔隙的孔径可以为0.04nm、0.1nm、0.3nm、0.4nm、0.7nm、1nm、1.3nm、1.5nm、1.8nm、2nm、3nm、4nm或5nm等。可选地，微介孔材料的内部孔隙的孔径满足：0.3nm≤d2≤2nm；可进一步提升对于正负极之间交互的抑制作用。
作为示例，上述提及的COF材料的内部孔隙的孔径可采用下述方法测得：取阻隔层置于NMP或水中浸泡24h；过滤溶解的材料粉体，并重新放入新的NMP溶剂或水中浸泡2h，之后再超声2h以使颗粒充分分散，重复清洗超声过程3次以上，最后得到COF材料，并放入真空干燥箱80℃干燥24h。采用气体吸附仪，在标准大气压下(101kPa)测试COF材料对N2的吸附量，测试所用气体的纯度为99.999％；将100mgCOF材料加入到石英样品管中，在快速比表面积分析仪的预处理站上120℃真空脱气6h。采用气体吸附仪对COF材料进行气体吸附实验，根据所得的氮气吸附曲线，利用离域密度泛函理论模型(NLDFT)对低压范围内(0.0255<P/P0<0.2)的吸附数据计算出COF材料的BET比表面积，在P/P0＝0.99处计算出的孔体积；孔径分布(PSD)由非定域密度函数理论(NLDFT)计算获得。
可理解地，形成MOF材料的无机金属中心和有机配体，决定了MOF材料的结构，并且MOF材料的结构决定了内部孔隙的孔径。
作为示例，上述提及的MOF材料的内部孔隙的孔径可采用下述方法测得：取阻隔层置于NMP或水中浸泡24h；过滤溶解的材料粉体，并重新放入新的NMP溶剂或水中浸泡2h，之后再超声2h 以使颗粒充分分散，重复清洗超声过程3次以上，最后得到MOF材料，并放入真空干燥箱80℃干燥24h。采用气体吸附仪，在标准大气压下(101kPa)测试MOF材料对N2的吸附量，测试所用气体的纯度为99.999％；将100mg MOF材料加入到石英样品管中，在快速比表面积分析仪的预处理站上120℃真空脱气6h。采用气体吸附仪对MOF材料进行气体吸附实验，根据所得的氮气吸附曲线，利用离域密度泛函理论模型(NLDFT)对低压范围内(0.0255<P/P0<0.2)的吸附数据计算出MOF材料的BET比表面积，在P/P0＝0.99处计算出的孔体积；孔径分布(PSD)由非定域密度函数理论(NLDFT)计算获得。
在一些实施方式中，在25℃时导离子无机材料的电导率≥0.0001mS·cm-1；导离子无机材料的电导率低于上述范围内时，可能会增大电池阻抗，恶化电池动力学性能。可选地，在25℃时所述导离子无机材料的电导率≥0.001mS·cm-1。进一步可选地，在25℃时所述导离子无机材料的电导率≥0.01mS·cm-1。
作为示例，上述提及的导离子无机材料的电导率可采用下述方法测得：将导离子无机材料制成固态电解质陶瓷样品，通过CHI660E电化学工作站对固态电解质陶瓷样品进行交流阻抗测试，用测试夹夹住以导电银浆作为电极的样品(即在电解质圆片两侧镀银)，测试频率范围为10^6Hz-0.1Hz。通过测试获得的阻抗图谱分析得到总阻抗值后计算相对应的总离子电导率。离子电导率是依据公式σ＝d/(R×P)×1000计算得到。其中σ为离子电导率，单位为mS·cm-1，d为电解质片的厚度，单位是cm；R为电化学工作站测得的电解质片的阻抗值，单位为欧姆；P为电解质片的底面积大小，单位是cm2。
在一些实施方式中，阻隔材料在阻隔层中的面积占比为30％-99％；例如，可以为35％-99％、40％-99％、50％-99％、60％-99％、70％-99％、80％-99％或90％-99％。阻隔材料在阻隔层中的单位面积占低于上述范围内时，可能会导致锂离子传输通道过少，可能增大电池阻抗。作为示例，阻隔材料在阻隔层中的单位面积占比为30％、40％、50％0、60％0、70％、80％、90％或99％等。可选地，阻隔材料在阻隔层中的单位面积占比为50％-99％。进一步可选地，阻隔材料在阻隔层中的单位面积占比为70％-99％。
需要说明的是，面积占比是指阻隔材料的面积占阻隔层总面积的比例。
作为示例，阻隔材料在阻隔层中的面积占比可采用下述方法测试得到：采用扫描电子显微镜拍摄阻隔层的SEM图，基于阻隔层的SEM图计算阻隔材料的总面积及阻隔层的面积；根据公式：阻隔材料的总面积/阻隔层的面积，计算阻隔材料在阻隔层中的面积占比。
在一些实施方式中，聚合物层包括溶胀度≤10％的聚合物。可选地，聚合物层中含有的聚合物的溶胀度均≤10％。聚合物的溶胀度满足上述范围时，在电解液溶剂中可不发生溶胀，稳定性好，同时可抑制电解液穿透阻隔层。
可选地，聚合物包括聚乙烯、聚丙烯、聚酰亚胺和聚偏二氟乙烯中的一种或多种。
需要说明的是，聚合物层中可以仅包括一种聚合物，也可以同时包括两种或两种以上的聚合物。
作为示例，上述提及的聚合物的溶胀度可以采用下述方法测得：取阻隔层样品，用游标卡尺或螺旋测微仪测量其厚度，计算其体积为T1，将该阻隔层样品加入碳酸二甲酯中浸泡12h，取出后测量该阻隔层样品的长宽高，计算其体积为T2；然后按照公式C＝(T2-T1)/T1×100％，计算聚合物的溶胀度。
在一些实施方式中，聚合物层在阻隔层中的质量占比≤50％；聚合物在阻隔层中的质量占比超过上述范围内时，可能会显著减慢锂离子传输速度，可能恶化电池阻抗。
可选地，聚合物层在阻隔层中的质量占为2％-30％；例如，可以为2％-25％、2％-20％、2％-15％、2％-10％或2％-5％等。作为示例，聚合物层在阻隔层中的质量占可以为2％、5％、10％、15％、20％、25％或30％等。进一步可选地，聚合物层在阻隔层中的质量占为5％-15％。
作为示例，上述提及的聚合物层在阻隔层中的质量占比可采用如下方法测试得到：使用热重-示差扫描量热分析连用仪分析阻隔层组分：取阻隔层15-25mg，置于氧化铝坩埚中，用氮气作为保护气，25℃预热30min后，以2℃/10min的速率升温至600℃，依据重量变化和热量变化确定每种组分的含量。
在一些实施方式中，聚合物层包括重均分子量为1W-200W的聚合物。可选地，聚合物层中含有的聚合物的重均分子量为1W-200W；例如，可以为1W-180W、1W-160W、1W-140W、1W-120W、1W-100W、1W-80W、1W-60W、1W-40W或1W-20W等。聚合物层中含有的聚合物的重均分子量低于上述范围时，可能无法满足阻隔层的强度需求。作为示例，聚合物层中含有的聚合物的重均分子 量可以为1W、10W、20W、30W、40W、50W、60W、70W、80W、90W、100W、110W、120W、130W、140W、150W、160W、170W、180W、190W或200W等。可选地，聚合物层包括重均分子量为2W-150W的聚合物。进一步可选地，聚合物层包括重均分子量为10W-100W的聚合物。
作为示例，上述提及的聚合物的重均分子量可以采用凝胶色谱法(GPC)进行测定。
在一些实施方式中，隔膜还包括支撑层，阻隔层位于支撑层的至少一侧。通过设置支撑层，可提高隔膜的强度。在一些实施方式中，支撑层具有孔隙，支撑层的孔隙的平均孔径为20nm-1000nm；例如，可以为20nm-900nm、20nm-800nm、20nm-700nm、20nm-600nm、20nm-500nm、20nm-400nm、20nm-300nm、20nm-200nm或20nm-100nm等。作为示例，支撑层的孔隙的平均孔径可以为20nm、100nm、200nm、300nm、400nm、500nm、600nm、700nm、800nm、900nm或1000nm等。可选地，支撑层的孔隙的平均孔径为100nm-500nm。
作为示例，上述提及的支撑层的孔隙的平均孔径可采用如下方法测试得到：采用孔径测试仪器对隔膜孔径进行测试，将待测试样品裁剪成直径为0.5cm的圆片，在浸润液中浸泡10min，用镊子将其转移到夹具中，压力范围设置为0-500PSI，进行孔径测试。
在一些实施方式中，支撑层的原料包括聚乙烯、聚丙烯、聚酰亚胺和聚偏二氟乙烯中的一种或多种。
在一些实施方式中，隔膜的厚度为2μm-12μm；例如，可以为2μm-11μm、2μm-10μm、2μm-9μm、2μm-8μm、2μm-7μm、2μm-6μm、2μm-5μm、2μm-4μm或2μm-3μm等。支撑层和阻隔层复合而成的隔膜的厚度满足上述范围时，可进一步提升隔膜的强度。作为示例，隔膜的厚度可以为2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm、10μm、11μm或12μm等。可选地，隔膜的厚度为3μm-10μm。进一步可选地，隔膜的厚度为5μm-7μm。
作为示例，上述提及的隔膜的厚度可采用下述方法测试得到：首先校准千分尺，然后将隔膜置于双砧之间，轻轻旋转套筒至出现响声，读数记录隔膜厚度。
在一些实施方式中，隔膜的透气度≥300s/100mL。隔膜的透气度满足上述范围时，可促进聚合物层和阻隔材料的紧密接触，阻隔层无空隙，减少正极电解液、负极电解液以及界面副产物的传输，抑制正负极之间的交互作用。可选地，隔膜的透气度≥400s/100mL；进一步可选地，隔膜的透气度≥500s/100mL。
需要说明的是，透气度是指一定体积的空气在单位压力下，通过单位面积隔膜所用的时间。
作为示例，上述提及的隔膜的透气度可采用如下方法测试得到：将隔膜平展，选取平整无油污的位置，放置在空气压缩筒出气口，旋紧固定；隔膜固定在工位后，用浮动在液体上的圆筒的自身重力来压缩筒内空气。随着空气通过试样，圆筒便会平稳下落。测量一定体积的空气，通过试样所需的时间，并按此计算透气度。其中，空气柱体积为100CC；测试面积为6.45cm2；样品面积＞6cm×6cm。
在一些实施方式中，隔膜的拉伸强度≥1000MPa。隔膜的拉伸强度满足上述范围时，可进一步提升阻隔层强度，使得电芯使用过程中，阻隔层可保持较好的结构强度。可选地，隔膜的拉伸强度≥1200MPa；进一步可选地，隔膜的拉伸强度≥1500MPa。
作为示例，上述提及的隔膜的拉伸强度可采用下述方法测试得到：将隔膜裁剪为15cm*2cm，并测量其厚度为A；然后将隔膜夹在万能测试仪上面，输入参数A和15cm后，开始测量；当隔膜被拉断之后就会显示出拉伸强度，读出拉伸强度。
本申请还提供了一种隔膜的制备方法，包括如下步骤：制备含有聚合物的溶液；将溶液负载在载体上，制备聚合物层；在聚合物层成膜之前，将阻隔材料负载在聚合物层表面；通过辊压将阻隔材料嵌入聚合物层中，干燥，移除载体，制备阻隔层。
可选地，含有聚合物的溶液的质量百分比浓度可以为2％-20％，可选为3％-7％。可选地，制备含有聚合物的溶液时采用的溶剂包括N-甲基吡咯烷酮。可选地，载体包括玻璃板。可选地，聚合物层的厚度为4μm-6μm。可选地，采用刮涂法将所述溶液负载在载体上。进一步可选地，刮涂时采用的刮刀的高度为10μm，涂布机的速度为25mm/s-35mm/s。可选地，干燥温度为75℃-85℃，干燥时间为10h-14h。
需要说明的是，上述提及的制备方法可用于制备仅包含有阻隔层的隔膜
作为示例，隔膜的制备方法包括如下步骤：将聚合物溶解在溶剂中直至澄清，制得质量百分比浓度为3％-7％的溶液；将溶液刮涂在玻璃板上，涂布厚度为4μm-6μm，获得负载在玻璃板上的聚合物层，其中，刮涂时采用的刮刀的高度为10μm，涂布机以25mm/s-35mm/s的速度带动刮刀运动； 在聚合物层成膜之前，将阻隔材料均匀喷洒在聚合物层表面，然后通过辊压将阻隔材料嵌入聚合物层中，将聚合物层置于真空干燥箱内在75℃-85℃干燥10h-14h，移除玻璃板，得到阻隔层。
本申请还提供了一种隔膜的制备方法，包括如下步骤：制备含有聚合物和阻隔材料的浆料；将基膜放置在抽滤器材中；向抽滤器材中加入浆料，抽滤，干燥，制备阻隔层。
可选地，制备含有聚合物和阻隔材料的浆料时采用的溶剂包括N-甲基吡咯烷酮。可选地，制备浆料时将聚合物、阻隔材料及溶剂的混合液以800rpm-1200rpm分散10h-14h。可选地，基膜包括PE膜。可选地，抽滤器材包括布氏漏斗。可选地，抽滤时间1.5h-2.5h。可选地，干燥温度为75℃-85℃，干燥时间为10h-14h。
需要说明的是，上述提及的制备方法可用于制备仅含有阻隔层的隔膜。
作为示例，隔膜的制备方法包括如下步骤：将聚合物溶解在溶剂中直至澄清，加入阻隔材料，以800rpm-1200rpm分散10h-14h，得到浆料；将PE膜放置在布氏漏斗上，平铺在布氏漏斗中，加入浆料，抽滤1.5h-2.5h；然后向布氏漏斗中加入去离子水以洗去残留的浆料；将PE膜由布氏漏斗中取下置于真空干燥箱内在75℃-85℃干燥10h-14h，得到阻隔层。
本申请还提供了一种隔膜的制备方法，包括如下步骤：制备含有聚合物的溶液；将溶液置于支撑层的至少一侧，制备聚合物层；在聚合物层成膜之前，将阻隔材料负载在聚合物层表面；通过辊压将阻隔材料嵌入聚合物层中，干燥，制备隔膜。
可选地，含有聚合物的溶液的质量百分比浓度可以为2％-20％，可选为3％-7％。可选地，制备含有聚合物的溶液时采用的溶剂包括N-甲基吡咯烷酮。可选地，载体包括玻璃板。可选地，聚合物层的厚度为4μm-6μm。可选地，采用刮涂法将所述溶液负载在载体上。进一步可选地，刮涂时采用的刮刀的高度为10μm，涂布机的速度为25mm/s-35mm/s。可选地，干燥温度为75℃-85℃，干燥时间为10h-14h。
需要说明的是，上述提及的制备方法可用于制备同时包含有阻隔层和支撑层的隔膜。
作为示例，隔膜的制备方法包括如下步骤：将聚合物溶解在溶剂中直至澄清，制得质量百分比浓度为3％-7％的溶液；将溶液刮涂在PE基膜上，涂布厚度为4μm-6μm，获得负载在PE基膜上的聚合物层，其中，刮涂时采用的刮刀的高度为10μm，涂布机以25mm/s-35mm/s的速度带动刮刀运动；在聚合物层成膜之前，将阻隔材料均匀喷洒在聚合物层表面，通过辊压将阻隔材料嵌入聚合物层中；然后于真空干燥箱内在75℃-85℃干燥10h-14h，得到隔膜。
本申请还提供了一种隔膜的制备方法，包括如下步骤：制备含有聚合物和阻隔材料的浆料；将浆料置于支撑层上，干燥，制备一次处理阻隔层；将一次处理阻隔层置于抽滤器材中；向抽滤器材中加入含有聚合物的溶液，抽滤，干燥，制备隔膜。
可选地，制备含有聚合物和阻隔材料的浆料时采用的溶剂包括N-甲基吡咯烷酮。可选地，制备浆料时将聚合物、阻隔材料及溶剂的混合液以1800rpm-2200rpm分散10h-14h。可选地，基膜包括PE膜。可选地，抽滤器材包括布氏漏斗。可选地，抽滤时间1.5h-2.5h。可选地，干燥温度为75℃-85℃，干燥时间为10h-14h。
需要说明的是，上述提及的制备方法可用于制备同时包含有阻隔层和支撑层的隔膜。
作为示例，隔膜的制备方法包括如下步骤：将聚合物溶解在溶剂中直至澄清，加入阻隔材料，以1800rpm-2200rpm分散10-14h，得到浆料；将溶液刮涂在PE膜上，涂布厚度为1.5μm-2.5μm，其中刮涂时采用的刮刀的高度为5μm，涂布机以25mm/s-35mm/s的速度带动刮刀运动；然后置于真空干燥箱内在75℃-85℃干燥10h-14h，得到负载在PE膜上的一次处理阻隔层；将PE膜和一次处理阻隔层平铺在布氏漏斗中，加入质量百分比浓度为3％-5％的聚合物溶液，抽滤1.5h-2.5h；接着向布氏漏斗中加入去离子水以洗去残留的聚合物溶液；将PE膜由布氏漏斗中取下置于真空干燥箱内在75℃-85℃干燥10h-14h，得到隔膜。
二次电池
本申请还提供了一种二次电池，包括正极极片、负极极片、正极电解液、负极电解液以及本申请上述的隔离膜；隔离膜位于正极极片和负极极片之间，正极电解液位于正极极片和隔离膜之间，负极电解液位于负极极片和隔离膜之间；正极电解液和负极电解液中含有的溶剂、锂盐和添加剂中的一项或多项是不同的。由此，所得的二次电池的存储性能和循环性能显著提高。
需要说明的是，在一些可能的实施方式中，在制备二次电池时，可将正极极片与负极极片紧贴隔离膜层叠放置，然后将三者放置于与隔离膜等长等宽的铝塑袋内，由于隔离膜与铝塑袋等长等宽，则可将除铝塑袋开口之外的其他三侧连同隔离膜一起热封，隔离膜和铝塑袋形成密度的正极腔室和 负极腔室，再将正极电解液和负极电解液从铝塑袋开口分别注入正极腔室和负极腔室，最后将铝塑袋开口热封制得电芯，将电芯放入外壳中，例如，外壳可以钢壳，制得二次电池。
作为一种可能的实施方式，在制备二次电池时，可将正极极片、负极极片和隔离膜卷绕，然后装入铝塑袋，将铝塑袋下端连同隔离膜一起热封，隔离膜和铝塑袋形成密度的正极腔室和负极腔室，再将正极电解液和负极电解液从铝塑袋开口分别注入正极腔室和负极腔室，最后将铝塑袋开口热封制得电芯，将电芯放入外壳中，例如，外壳可以钢壳，制得二次电池。需要说明的是，常规电解液中，溶剂、锂盐和添加剂对正极和负极的兼容性往往不同，因此通常需要将溶剂、锂盐和添加剂搭配使用，以同时保护正极和负极。本申请中，由于隔膜可抑制正极电解液和负极电解液的交换，则可根据正极和负极自身的特性分别设计电解液，而不用考虑与另一侧的兼容性；因此能够进一步放大不同电解液的优势，提升电芯的性能，推动电解液的极限设计。
以下适当参照附图对本申请的二次电池、电池模块、电池包和用电装置进行说明。
在一些实施方式中，正极电解液的溶剂和负极电解液的溶剂不同。
可理解地，由于隔膜将正极电解液和负极电解液隔开，则正极电解液和负极电解液可分别采用与其相匹配的溶剂体系。例如，正极电解液可采用耐氧化的溶剂体系，进而可大幅度减少电解液氧化，提升电芯性能；负极电解液可采用与负极相兼容且粘度较低的溶剂体系，从而能显著改善负极界面稳定性，同时提升锂离子在负极处的传输速率。
需要说明的是，正极电解液采用的溶剂种类和负极电解液采用的溶剂种类完全不同时，属于正极电解液的溶剂和负极电解液的溶剂不同的范畴。例如，正极电解液采用的溶剂为E，负极电解液采用的溶剂为F，则正极电解液的溶剂和负极电解液的溶剂不同。
正极电解液和负极电解液均采用多种溶剂的混合物，且正极电解液和负极电解液中采用的溶剂种类相同，但是不同溶剂之间的体积占比或质量占比不同时，亦属于正极电解液的溶剂和负极电解液的溶剂不同的范畴。例如，正极电解液采用的溶剂为体积比为5:5的E和F的混合物，负极电解液采用的溶剂为体积比为3:7的E和F的混合物，则正极电解液的溶剂和负极电解液的溶剂不同。
正极电解液和负极电解液采用的溶剂种类有部分相同时，亦属于正极电解液的溶剂和负极电解液的溶剂不同的范畴。例如，正极电解液采用的溶剂为E，负极电解液采用的溶剂为E和F的混合物，则正极电解液的溶剂和负极电解液的溶剂不同。正极电解液采用的溶剂为E和G的混合物，负极电解液采用的溶剂为E和F的混合物，则正极电解液的溶剂和负极电解液的溶剂亦不同。
可选地，正极电解液的溶剂包括碳酸酯类溶剂、氟代碳酸酯类溶剂、氟代羧酸酯类溶剂、砜类溶剂、氟代砜类溶剂、磷酸酯类溶剂、硼酸酯类溶剂和腈类溶剂中的一种或多种。
可选地，负极电解液的溶剂包括碳酸酯类溶剂、羧酸酯类溶剂、醚类溶剂、氟代羧酸酯类溶剂和氟代碳酸酯类溶剂中的一种或多种。
在一些实施方式中，氟代碳酸酯类溶剂包括甲基三氟乙基碳酸酯、二(三氟甲基)碳酸酯、二(三氟乙基)碳酸酯、4-三氟甲基碳酸乙烯酯、双氟代碳酸乙烯酯、三氟甲基三氟乙基碳酸酯、三氟丙基碳酸酯和2,2-二氟乙基甲基碳酸酯中的一种或多种；氟代羧酸酯类溶剂包括3,3,3-三氟乙酸三氟乙酯、乙酸2,2-二氟乙酯、二氟乙酸乙酯和乙酸2,2,2-三氟乙酯中的一种或多种；砜类溶剂包括环丁砜、二甲基砜、二乙基砜、甲基乙基砜、甲基异丙基砜、二甲基亚砜、二乙基亚砜和甲基乙基亚砜中的一种或多种；氟代砜类溶剂包括甲基三氟甲基砜、乙基三氟甲基砜、丙基三氟甲基砜、甲基三氟乙基砜、甲基三氟丙基砜、1,1,2,2-四氟丙基甲基砜、三氟甲基异丙基砜和甲基六氟异丙基砜中的一种或多种；磷酸酯类溶剂包括磷酸三甲酯、磷酸三乙酯、磷酸三丙酯、磷酸异丙基酯、磷酸三(六氟异丙基)酯和磷酸三(2,2,2-三氟乙基)酯中的一种或多种；硼酸酯类溶剂包括硼酸三甲酯、硼酸三乙酯、硼酸三(六氟异丙基)酯和硼酸三(2,2,2-三氟乙基)酯中的一种或多种；腈类溶剂包括乙腈、琥珀腈、丁二腈、戊二腈、己二腈、1,4-二氰基-2-丁烯、1,3,6-己烷三腈、乙二醇双丙腈醚和1,2,3-三氰乙氧基中的一种或多种；碳酸酯类溶剂包括碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯和碳酸乙烯酯中的一种或多种；羧酸酯类溶剂包括甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯和丙酸丙酯中的一种或多种；醚类溶剂包括1,2-二甲氧基乙烷、四乙醇二甲醚、γ-丁内酯和四氢呋喃中的一种或多种。
可选地，正极电解液的溶剂包括二(三氟甲基)碳酸酯、二(三氟乙基)碳酸酯、双氟代碳酸乙烯酯、乙酸2,2-二氟乙酯、二氟乙酸乙酯、二乙基砜、甲基乙基砜、甲基三氟甲基砜、乙基三氟甲基砜、磷酸三乙酯、磷酸三丙酯、乙腈、琥珀腈和丁二腈中的一种或多种。
可选地，负极电解液的溶剂包括碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯和碳酸乙烯酯、1,2-二甲 氧基乙烷和四乙醇二甲醚中的一种或多种。
在一些实施方式中，正极电解液的锂盐和负极电解液的锂盐不同。
需要说明的是，正极电解液含有的锂盐种类和负极电解液含有的锂盐种类完全不同时，属于正极电解液的锂盐和负极电解液的锂盐不同的范畴。例如，正极电解液含有的锂盐为a，负极电解液采用的锂盐为b，则正极电解液的锂盐和负极电解液的锂盐不同。
正极电解液含有的锂盐种类和负极电解液含有的锂盐种类完全相同，但是锂盐的质量体积浓度或者摩尔浓度不同时，属于正极电解液的锂盐和负极电解液的锂盐不同的范畴。例如，正极电解液含有的锂盐为a，摩尔浓度为1mol/L；负极电解液采用的锂盐为a，摩尔浓度为1.5mol/L，则正极电解液的锂盐和负极电解液的锂盐不同。
正极电解液和负极电解液均采用多种锂盐，且正极电解液和负极电解液中采用的锂盐种类完全相同，但是不同锂盐之间的质量比或摩尔比不同时，亦属于正极电解液的锂盐和负极电解液的锂盐不同的范畴。例如，正极电解液中的锂盐为摩尔比为5:5的a和b的混合物，负极电解液中的锂盐为摩尔比为3:7的a和b的混合物，则正极电解液的锂盐和负极电解液的锂盐不同。进一步地，正极电解液和负极电解液中的锂盐种类及不同锂盐之间的摩尔比或质量比完全相同时，但是锂盐的总质量体积浓度或者总摩尔浓度不同时，亦属于正极电解液的锂盐和负极电解液的锂盐不同的范畴。例如，正极电解液中的锂盐和负极电解液中的锂盐均为摩尔比为5:5的a和b的混合物，但正极电解液中的锂盐的总摩尔浓度为1mol/L，负极电解液中的锂盐的总摩尔浓度为1.5mol/L，则正极电解液的锂盐和负极电解液的锂盐不同。
正极电解液和负极电解液中含有的锂盐种类有部分相同时，亦属于正极电解液的锂盐和负极电解液的锂盐不同的范畴。例如，正极电解液中含有的锂盐为a，负极电解液中含有的锂盐为a和b的混合物，则正极电解液的锂盐和负极电解液的溶锂盐不同。正极电解液中含有的锂盐为a和c的混合物，负极电解液中含有的锂盐为a和c的混合物，则正极电解液的锂盐剂和负极电解液的锂盐亦不同。
在一些实施方式中，正极电解液的锂盐包括六氟磷酸锂、四氟硼酸锂、双氟磺酰亚胺锂和二草酸硼酸锂中的一种或多种。
在一些实施方式中，正极电解液的锂盐还可包括高氯酸锂(LiClO4)、六氟砷酸锂(LiAsF6)、双三氟甲磺酰亚胺锂(LiTFSI)、三氟甲磺酸锂(LiTFS)、二氟草酸硼酸锂(LiDFOB)、二氟磷酸锂(LiPO2F2)、二氟二草酸磷酸锂(LiDFOP)及四氟草酸磷酸锂(LiTFOP)中的一种或几种。正极电解液中锂盐的浓度通常为0.5mol/L-4mol/L。
在一些实施方式中，负极电解液的锂盐包括六氟磷酸锂、四氟硼酸锂、双氟磺酰亚胺锂和二草酸硼酸锂中的一种或多种。
在一些实施方式中，负极电解液的锂盐还可包括高氯酸锂(LiClO4)、六氟砷酸锂(LiAsF6)、双三氟甲磺酰亚胺锂(LiTFSI)、三氟甲磺酸锂(LiTFS)、二氟草酸硼酸锂(LiDFOB)、二氟磷酸锂(LiPO2F2)、二氟二草酸磷酸锂(LiDFOP)及四氟草酸磷酸锂(LiTFOP)中的一种或几种。负极电解液中锂盐的浓度通常为0.5mol/L-4mol/L。
在一些实施方式中，所述正极电解液还可选地包括添加剂。例如添加剂可以包括正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
在一些实施方式中，所述负极电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。正极电解液和负极电解液在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使离子通过。
正极极片
正极极片包括正极集流体以及设置在正极集流体至少一侧的正极膜层，所述正极膜层包括正极活性材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在一些实施方式中，正极活性材料可包含本领域公知的用于电池的正极活性材料。作为示例， 正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO2)、锂镍氧化物(如LiNiO2)、锂锰氧化物(如LiMnO2、LiMn2O4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi1/3Co1/3Mn1/3O2(也可以简称为NCM333)、LiNi0.5Co0.2Mn0.3O2(也可以简称为NCM523)、LiNi0.5Co0.25Mn0.25O2(也可以简称为NCM211)、LiNi0.6Co0.2Mn0.2O2(也可以简称为NCM622)、LiNi0.8Co0.1Mn0.1O2(也可以简称为NCM811)、锂镍钴铝氧化物(如LiNi0.85Co0.15Al0.05O2)及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。所述正极活性材料在正极膜层中的重量比为80-100重量％，基于正极膜层的总重量计。
在一些实施方式中，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料形成在高分子材料基材上而形成。其中，金属材料包括但不限于铝、铝合金、镍、镍合金、钛、钛合金和银及银合金中的一种或多种。高分子材料基材包括但不限于聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)和聚乙烯(PE)中的至少一种。
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。所述粘结剂在正极膜层中的重量比为0-20重量％，基于正极膜层的总重量计。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。所述导电剂在正极膜层中的重量比为0-20重量％，基于正极膜层的总重量计。
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂中，形成正极浆料，其中所述正极浆料固含量为40-80wt％，室温下的粘度调整到5000-25000mPa·s，溶剂可包括但不限于N-甲基吡咯烷酮，将正极浆料涂覆在正极集流体的双侧表面上，烘干后经过冷轧机冷压后形成正极极片；正极粉末单侧涂布单位面密度为150-450mg/m2，正极极片压实密度为2.0-4.3g/cm3，可选为3.5-4.3g/cm3。所述压实密度的计算公式为
压实密度＝涂布面密度/(挤压后极片厚度-集流体厚度)。
负极极片
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料形成在高分子材料基材上而形成。其中，金属材料包括但不限于铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等，高分子材料基材包括但不限于聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等基材。
在一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。所述负极活性材料在负极膜层中的重量比为70-100重量％，基于负极膜层的总重量计。
在一些实施方式中，负极膜层还可选地包括粘结剂。所述粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。所述粘结剂在负极膜层中的重量比为0-30重量％，基于负极膜层的总重量计。
在一些实施方式中，负极膜层还可选地包括导电剂。导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。所述导电剂在负极膜层中的重量比为0-20重量％，基于负极膜层的总重量计。
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂等；其中，增稠剂包括但不限于羧甲基纤维素钠(CMC-Na)等。所述其他助剂在负极膜层中的重量比为0-15重量％，基于负极膜层的总重量计。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂中，形成负极浆料，其中所述负极浆料固含量为30-70wt％，室温下的粘度调整到2000-10000mPa·s，溶剂可包括但不限于去离子水；将所得到的负极浆料涂覆在负极集流体双侧表面上，经过干燥工序，冷压例如对辊，得到负极极片。负极粉末单侧涂布单位面密度为75-220mg/m2，负极极片压实密度1.2-2.0g/m3。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
以叠片工艺制备电极组件时，将正极极片与负极极片紧贴隔离膜放置后，将三者放置于与隔离膜等长等宽的铝塑袋内，将除铝塑袋开口之外的其他三侧连同隔离膜一起热封，隔离膜和铝塑袋形成密度的正极腔室和负极腔室，再将正极电解液和负极电解液从铝塑袋开口分别注入正极腔室和负极腔室，最后将铝塑袋开口热封制得电芯。
以卷绕工艺制备电极组件时，可将正极极片、负极极片和隔离膜卷绕，然后装入铝塑袋，将铝塑袋下端连同隔离膜一起热封，隔离膜和铝塑袋形成密度的正极腔室和负极腔室，再将正极电解液和负极电解液从铝塑袋开口分别注入正极腔室和负极腔室，最后将铝塑袋开口热封制得电芯。
在一些实施方式中，二次电池可包括外包装。该外包装可用于封装上述电芯。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
在一些实施方式中，二次电池为锂离子电池。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图8是作为一个示例的方形结构的二次电池1。
在一些实施例中，参照图9，外包装可包括壳体11和盖板13。其中，壳体11可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体11具有与容纳腔连通的开口，盖板13能够盖设于所述开口，以封闭所述容纳腔。
正极极片、负极极片和隔膜可经卷绕工艺或叠片工艺形成电极组件12。电极组件12封装于所述容纳腔。将正极电解液浸入正极极片和隔膜之间，负极电解液浸入负极极片和隔膜之间。二次电池1所含电极组件12的数量可以为一个或多个，可根据需求来调节。
在一些实施例中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为多个，具体数量可根据电池模块的应用和容量来调节。
在电池模块中，多个二次电池可以是沿电池模块的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池进行固定。
可选地，电池模块还可以包括具有容纳空间的外壳，多个二次电池容纳于该容纳空间。
在一些实施例中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以根据电池包的应用和容量进行调节。
在电池包中可以包括电池箱和设置于电池箱中的多个电池模块。电池箱包括上箱体和下箱体，上箱体能够盖设于下箱体，并形成用于容纳电池模块的封闭空间。多个电池模块可以按照任意的方式排布于电池箱中。
用电装置
本申请还提供一种用电装置，所述用电装置包括所述的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块或电池包可以用作所述装置的电源，也可以作为所述装置的能量存储单元。所述装置可以但不限于是移动设备、电动车辆、电气列车、船舶及卫星、储能系统等； 其中，移动设备可包括但不限于手机、笔记本电脑等中的至少一种；电动车辆可包括但不限于纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等中的至少一种。
所述装置可以根据其使用需求来选择二次电池、电池模块或电池包。
图10是作为一个示例的用电装置2。该用电装置2为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用二次电池作为电源。
以下结合实施例进一步说明本申请的有益效果。
实施例
为了使本申请所解决的技术问题、技术方案及有益效果更加清楚，以下将结合实施例和附图进行进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本申请及其应用的任何限制。基于本申请中的实施例，本领域普通技术人员在没有付出创造性劳动前提下所获得的所有其他实施例都属于本申请保护的范围。本申请的实施例和对比例中所用的材料均可以通过商购获得。
实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
一、微介孔材料的制备
1、COF-1合成
在反应器中加入0.1g摩尔比约1:1的六(4-甲酰基苯基)苯和对苯二胺，接着加入3g的1,4-二氧六环，超声5min。在氮气保护下，缓慢加入适0.3g的6moL/L的醋酸溶液，转移至烘箱120℃反应48h。将反应产物过滤，滤渣放入索氏提取器用丙酮提纯20h，提纯后固体放入80℃真空干燥箱干燥24h得到产物，将其命名为COF-1。COF-1的反应过程如图1所示。
采用型号Quantachrome(ASiQMVH002 5)的气体吸附仪，在标准大气压下(101kPa)测试COF-1材料对N2的吸附量，测试所用气体的纯度为99.999％；测试步骤：将100mg的COF-1加入到石英样品管中，在快速比表面积分析仪的预处理站上120℃真空脱气6h。采用气体吸附仪对COF-1进行气体吸附实验，根据所得的氮气吸附曲线，孔径分布(PSD)由非定域密度函数理论(NLDFT)计算获得，COF-1内部孔隙的孔径主要集中在0.67nm左右，则COF-1内部孔隙的孔径为0.67nm。
2、MOF-1合成
称取0.3787g N-甲基咪唑，加入30mL乙醇使其溶解(烧瓶中加磁子),称取0.3798g醋酸锌，加入30mL乙醇使其溶解，然后将该溶液加入到上述溶液中，100℃下静置12h，离心得到固体。
采用与COF-1相同的测试方法，测得MOF-1的内部孔隙的孔径为0.34nm。
3、COF-2合成
在反应器中加入0.1g摩尔比约1:1的1,3,5-三[4-氨基(苯-4-基)]苯和4,4′-(6-苯基菲-3,8-二酰基)二苯甲醛，接着加入3g的1,4-二氧六环，充分溶解。在氮气保护下，加入3g的模板剂均三甲苯，静置5min后，缓慢加入0.3g mol/L的醋酸溶液，转移至烘箱，120℃反应72h。将反应产物过滤，滤渣放入索氏提取器用甲醇提纯30h，提纯后固体放入80℃真空干燥箱干燥24h得到产物，将其命名为COF-2。COF-2的结构示意图如图2所示。
采用与COF-1相同的测试方法，测得COF-2的内部孔隙的孔径为4.8nm。
4、COF-3合成
在反应器中加入0.1g摩尔比约为1:1的1,3,5三甲醛-2,4,6甲氧基苯和对1,3,5三氨基-2,4,6甲氧基苯，接着加入3g的1,4-二氧六环和3g模板剂均三甲苯，充分溶解。在氮气保护下，缓慢加入0.3g的6mol/L的醋酸溶液，转移至烘箱，120℃反应72h。将反应产物过滤，滤渣放入索氏提取器用四氢呋喃提纯30h，提纯后固体放入80℃真空干燥箱干燥24h得到产物，将其命名为COF-3。COF-3的结构示意图如图3所示。
采用与COF-1相同的测试方法，测得COF-3的内部孔隙的孔径为0.3nm。
5、COF-4合成
在反应器中加入0.1g的1,4-亚甲基二硼酸-2,5-二甲基苯，接着加入3g质量比为4:1的乙腈和1,4二氧六环混合液，超声后充分溶解，将反应器用氮气保护并密封，转移至烘箱，90℃反应72h。将 反应物过滤，滤渣用索式提取器用四氢呋喃提纯30h，提纯后固体放入80℃真空干燥箱干燥24h得到产物，将其命名为COF-4。COF-4的结构如图4所示。
采用与COF-1相同的测试方法，测得COF-4的内部孔隙的孔径为0.8nm。
6、COF-5合成
在反应器中加入0.1g摩尔比约1:1的水合肼和三醛基间苯三酚，接着加入3g质量比为1:1的四氢呋喃/乙醇混合液，充分溶解。在氮气保护下，缓慢加入0.3g的6mol/L的醋酸溶液，转移至烘箱，120℃反应120h。将反应产物过滤，滤渣放入索氏提取器用四氢呋喃提纯30h，提纯后固体放入80℃真空干燥箱干燥24h得到产物，将其命名为COF-5。COF-5的结构示意图如图5所示。
采用与COF-1相同的测试方法，测得COF-5的内部孔隙的孔径为0.97nm。
7、COF-6合成
在反应器中加入0.1g摩尔比约1:1的联苯胺和三醛基间苯三酚，接着加入3g质量比为1:1的四氢呋喃/乙醇混合液，充分溶解。在氮气保护下，缓慢加入0.3g的6mol/L的醋酸溶液，转移至烘箱，120℃反应120h。将反应产物过滤，滤渣放入索氏提取器用四氢呋喃提纯30h，提纯后固体放入80℃真空干燥箱干燥24h得到产物，将其命名为COF-6。COF-6的结构示意图如图6所示。
采用与COF-1相同的测试方法，测得COF-6的内部孔隙的孔径为2nm。
8、COF-7合成
在反应器中加入0.1g摩尔比约1:1的1,3,5-三[4-氨基(1,1-联苯-4-基)]苯和4,4′-(6-苯基菲-3,8-二酰基)二苯甲醛，接着加入3g的1,4-二氧六环，充分溶解。在氮气保护下，加入3g的模板剂均三甲苯，静置5min后，缓慢加入0.3g mol/L的醋酸溶液，转移至烘箱，120℃反应72h。将反应产物过滤，滤渣放入索氏提取器用甲醇提纯30h，提纯后固体放入80℃真空干燥箱干燥24h得到产物，将其命名为COF-7。COF-7的结构示意图如图7所示。
采用与COF-1相同的测试方法，测得COF-7的内部孔隙的孔径为5.8nm。
需要说明的是，由于合成COF材料采用的单体相同时，则制得的COF材料的内部孔隙的孔径相同；可进一步通过控制COF材料制备过程中的温度和时间等反应条件，调配最后制得的COF材料的体积平均粒径Dv50。为了便于描述，本申请中将采用相同单体合成的具有相同的内部孔隙孔径的COF材料，进行统一命名。
二、隔膜的制备
实施例1
将聚偏二氟乙烯(作为聚合物)溶解在N-甲基吡咯烷酮中直至澄清，配制得到质量百分比浓度为5％的聚合物溶液；然后加入COF-1(作为阻隔材料)，以1000rpm的分散速度高速分散12h，制得浆料。
将厚度为7μm、孔径为20nm的PE膜(作为聚合物层)平铺在布氏漏斗中，加入浆料，抽滤2h；然后向布氏漏斗中加入去离子水洗去残留的浆料；接着将PE膜由布氏漏斗中取下置于真空干燥箱内在80℃干燥12h，得到隔膜。
实施例2-37
实施例2-15、实施例18以及实施例22-34中隔膜的制备方法和实施例1中隔膜的制备方法基本相似，区别主要在于：阻隔材料的种类、阻隔材料的体积平均粒径Dv50、阻隔材料内部孔隙的孔径、阻隔层的厚度、阻隔层厚度与阻隔材料的体积平均粒径Dv50的比值、阻隔层的透气度、导离子无机材料的电导率、聚合物的种类和/或重均分子量和/或溶胀度、聚合物层在阻隔层中的质量占比、阻隔材料在阻隔层中的面积占比中的一项或多项不同，具体详见表1。
实施例16-17、实施例19-21以及实施例35-37中隔膜的制备方法和实施例1中隔膜的制备方法不同，且阻隔材料的种类、阻隔材料的体积平均粒径Dv50、阻隔材料内部孔隙的孔径、阻隔层的厚度、阻隔层厚度与阻隔材料的体积平均粒径Dv50的比值、阻隔层的透气度、导离子无机材料的电导率、聚合物的种类和/或重均分子量和/或溶胀度、聚合物层在阻隔层中的质量占比、阻隔材料在阻隔层中的面积占比、聚合物的种类、支撑层种类、支撑层孔径和隔膜的厚度中的一项或多项，具体详见表1。需要说明的是，实施例16-17、实施例19-21以及实施例36-37中隔膜的厚度是指同时包括支撑层和阻隔层时的隔膜的厚度。
实施例16中隔膜的制备方法为：将聚偏二氟乙烯(作为聚合物)溶解在N-甲基吡咯烷酮中直至澄清，加入LATP(作为阻隔材料)以2000rmp的分散速度高速分散12h，得到浆料。将浆料涂布在厚度为7μm的PE膜(作为支撑层)上，形成阻隔层，涂布厚度为2μm；其中，刮涂时采用的刮刀的高度 为5μm，涂布机以30mm/s的速度带动刮刀运动。然后将负载有阻隔层的PE膜置于真空干燥箱内以80℃干燥12h，得到一次处理阻隔层。将负载有一次处理阻隔层的PE膜平铺在布氏漏斗中，加入质量百分比浓度为5％的聚偏二氟乙烯溶液，抽滤2h；接着向布氏漏斗中加入去离子水以洗去残留的聚偏二氟乙烯溶液；将PE膜由布氏漏斗中取下置于真空干燥箱内在80℃干燥12h，得到隔膜。
实施例17中隔膜的制备方法为：将聚偏二氟乙烯(作为聚合物)溶解在N-甲基吡咯烷酮中直至澄清，加入LLTO(作为阻隔材料)以2000rmp的分散速度高速分散12h，得到浆料。将浆料涂布在厚度为7μm的PE膜(作为支撑层)上，形成阻隔层，涂布厚度为2μm；其中，刮涂时采用的刮刀的高度为5μm，涂布机以30mm/s的速度带动刮刀运动。然后将负载有阻隔层的PE膜置于真空干燥箱内以80℃干燥12h，得到一次处理阻隔层。将负载有一次处理阻隔层的PE膜平铺在布氏漏斗中，加入质量百分比浓度为5％的聚偏二氟乙烯溶液，抽滤2h；接着向布氏漏斗中加入去离子水以洗去残留的聚偏二氟乙烯溶液；将PE膜由布氏漏斗中取下置于真空干燥箱内在80℃干燥12h，得到隔膜。
实施例19中隔膜的制备方法为：将聚酰亚胺(作为聚合物)溶解在N-甲基吡咯烷酮中直至澄清，配制得到质量百分比浓度为5％的聚合物溶液。将聚合物溶液刮涂在厚度为7μm的PE膜(作为支撑层)上，涂布厚度为1μm，获得负载在PE膜上的聚合物层；其中，刮涂时采用的刮刀的高度为10μm，涂布机以30mm/s的速度带动刮刀运动。在聚合物层未成膜之前，将LSPS(作为阻隔材料)均匀喷洒在聚合物层表面，通过辊压将LSPS嵌入聚合物层中，然后于真空干燥箱内以80℃干燥12h，得到隔膜。
实施例20中隔膜的制备方法为：将聚酰亚胺(作为聚合物)溶解在N-甲基吡咯烷酮中直至澄清，配制得到质量百分比浓度为5％的聚合物溶液。将聚合物溶液刮涂在厚度为7μm的PE膜(作为支撑层)上，涂布厚度为1μm，获得负载在PE膜上的聚合物层；其中，刮涂时采用的刮刀的高度为10μm，涂布机以30mm/s的速度带动刮刀运动。在聚合物层未成膜之前，将LATP(作为阻隔材料)均匀喷洒在聚合物层表面，通过辊压将LATP嵌入聚合物层中，然后于真空干燥箱内以80℃干燥12h，得到隔膜。
实施例21中隔膜的制备方法为：将聚偏二氟乙烯(作为聚合物)溶解在N-甲基吡咯烷酮中直至澄清，配制得到质量百分比浓度为5％的聚合物溶液。将聚合物溶液刮涂在厚度为7μm的PE膜(作为支撑层)上，涂布厚度为1μm，获得负载在PE膜上的聚合物层；其中，刮涂时采用的刮刀的高度为10μm，涂布机以30mm/s的速度带动刮刀运动。在聚合物层未成膜之前，将LATP(作为阻隔材料)均匀喷洒在聚合物层表面，通过辊压将LATP嵌入聚合物层中，然后于真空干燥箱内以80℃干燥12h，得到隔膜。
实施例35中隔膜的制备方法为：将聚偏二氟乙烯(作为聚合物)溶解在N-甲基吡咯烷酮中直至澄清，配制得到质量百分比浓度为5％的聚合物溶液。将聚合物溶液刮涂在玻璃板上，涂布厚度为5μm，获得负载在玻璃板上的聚合物层；其中，刮涂时采用的刮刀的高度为10μm，涂布机以30mm/s的速度带动刮刀运动。在聚合物层未成膜之前，将COF-1(作为阻隔材料)均匀喷洒在聚合物层表面，通过辊压将COF-1材料嵌入聚合物层中，然后于真空干燥箱内以80℃干燥12h，移除玻璃板，得到隔膜。
实施例36中隔膜的制备方法为：将聚偏二氟乙烯(作为聚合物)溶解在N-甲基吡咯烷酮中直至澄清，配制得到质量百分比浓度为5％的聚合物溶液。将聚合物溶液刮涂在厚度为7μm的PE膜(作为支撑层)上，涂布厚度为1μm，获得负载在PE膜上的聚合物层；其中，刮涂时采用的刮刀的高度为10μm，涂布机以30mm/s的速度带动刮刀运动。在聚合物层未成膜之前，将COF-1(作为阻隔材料)均匀喷洒在聚合物层表面，通过辊压将COF-1材料嵌入聚合物层中，然后于真空干燥箱内以80℃干燥12h，得到隔膜。
实施例37中隔膜的制备方法为：将聚偏二氟乙烯(作为聚合物)溶解在N-甲基吡咯烷酮中直至澄清，加入COF-1(作为阻隔材料)以2000rmp的分散速度高速分散12h，得到浆料。将浆料涂布在厚度为7μm的PP膜(作为支撑层)上，形成阻隔层，涂布厚度为2μm；其中，刮涂时采用的刮刀的高度为5μm，涂布机以30mm/s的速度带动刮刀运动。然后将负载有阻隔层的PP膜置于真空干燥箱内以80℃干燥12h，得到一次处理阻隔层。将负载有一次处理阻隔层的PP膜平铺在布氏漏斗中，加入质量百分比浓度为5％的聚偏二氟乙烯溶液，抽滤2h；接着向布氏漏斗中加入去离子水以洗去残留的聚偏二氟乙烯溶液；将PP膜由布氏漏斗中取下置于真空干燥箱内在80℃干燥12h，得到隔膜。
对比例1
对比例1中采用普通PP膜作为隔膜。
对比例2
对比例2中隔膜的制备方法和实施例1中隔膜的制备方法基本相似，区别主要在于：抽滤时仅对1/2面积的PE膜进行抽滤，其余部分未进行处理，各参数设置具体详见表1。
对比例3
对比例3中隔膜的制备方法和实施例1中隔膜的制备方法基本相似，区别主要在于：阻隔材料的种类、阻隔材料的体积平均粒径Dv50、阻隔材料内部孔隙的孔径、阻隔层的厚度、阻隔层厚度与阻隔材料的体积平均粒径Dv50的比值、阻隔层的透气度、导离子无机材料的电导率、聚合物的种类和/或重均分子量和/或溶胀度、聚合物层在阻隔层中的质量占比、阻隔材料在阻隔层中的面积占比中的一项或多项不同，具体详见表1。
需要说明的是，上述提及的阻隔材料的体积平均粒径Dv50采用麦奇克S3500系列(Microtrac MRB S3500)激光粒度分析测得；具体过程为：取2g阻隔材料，加入20mL去离子水，超声5min，确保样品完全分散得分散液，然后将分散液放入样品槽后测试，得到阻隔材料的体积平均粒径Dv50。
上述提及的阻隔材料COF-1内部孔隙的孔径采用下述方法测试得到：取待测COF-1材料，采用型号为Quantachrome(ASiQMVH002 5)的气体吸附仪，在标准大气压下(101kPa)测试COF材料对N2的吸附量，测试所用气体的纯度为99.999％；将100mgCOF材料加入到石英样品管中，在快速比表面积分析仪的预处理站上120℃真空脱气6h。采用气体吸附仪对COF材料进行气体吸附实验，根据所得的氮气吸附曲线，利用离域密度泛函理论模型(NLDFT)对低压范围内(0.0255<P/P0<0.2)的吸附数据计算出COF材料的BET比表面积，在P/P0＝0.99处计算出的孔体积；孔径分布(PSD)由非定域密度函数理论(NLDFT)计算获得。
上述提及的阻隔材料MOF-1内部孔隙的孔径采用下述方法测试得到：取待测MOF-1材料，采用型号为Quantachrome(ASiQMVH002 5)的气体吸附仪，在标准大气压下(101kPa)测试MOF材料对N2的吸附量，测试所用气体的纯度为99.999％；将100mgMOF材料加入到石英样品管中，在快速比表面积分析仪的预处理站上120℃真空脱气6h。采用气体吸附仪对MOF材料进行气体吸附实验，根据所得的氮气吸附曲线，利用离域密度泛函理论模型(NLDFT)对低压范围内(0.0255<P/P0<0.2)的吸附数据计算出MOF材料的BET比表面积，在P/P0＝0.99处计算出的孔体积；孔径分布(PSD)由非定域密度函数理论(NLDFT)计算获得。
上述提及的阻隔材料LLZO、LLTO、LATP、LAGP及LSPS的电导率采用下述方法测得：将导离子无机材料制成固态电解质陶瓷样品，通过CHI660E电化学工作站对固态电解质陶瓷样品进行交流阻抗测试，用测试夹夹住以导电银浆作为电极的样品(即在电解质圆片两侧镀银)，测试频率范围为10^6Hz-0.1Hz。通过测试获得的阻抗图谱分析得到总阻抗值后计算相对应的总离子电导率。离子电导率是依据公式σ＝d/(R×P)×1000计算得到。其中σ为离子电导率，单位为mS·cm-1，d为电解质片的厚度，单位是cm；R为电化学工作站测得的电解质片的阻抗值，单位为欧姆；P为电解质片的底面积大小，单位是cm2。
上述提及的阻隔材料在阻隔层中的面积占比采用下述方法测试得到：采用扫描电子显微镜拍摄阻隔层的SEM图，基于阻隔层的SEM图计算阻隔材料的总面积及阻隔层的面积；根据公式：阻隔材料的总面积/阻隔层的面积，计算阻隔材料在阻隔层中的面积占比。
上述提及的聚合物的溶胀度采用下述方法测试得到：于25℃下将聚合物样品置于玻璃板上刮膜，取1cm×1cm大小的聚合物膜片，60℃真空干燥后，天平称重M1，将该聚合物膜片加入碳酸二甲酯中浸泡12h，取出后用无尘纸擦去表面溶液，称重M2；然后按照公式C＝(M2-M1)/M1×100％，计算聚合物的溶胀度。
上述提及的聚合物层在阻隔层中的质量占比采用下述方法测试得到：使用热重-示差扫描量热分析连用仪分析阻隔层组分：取阻隔层15-25mg，置于氧化铝坩埚中，用氮气作为保护气，25℃预热30min后，以2℃/10min的速率升温至600℃，依据重量变化和热量变化确定每种组分的含量。
上述提及的阻隔层的透气度的测试方法为：将阻隔层平展，选取平整无油污的位置，放置在空气压缩筒出气口，旋紧固定；阻隔层固定在工位后，用浮动在液体上的圆筒的自身重力来压缩筒内空气。随着空气通过试样，圆筒便会平稳下落。测试一定体积的空气，通过试样所需的时间，并按此计算透气度。其中，空气柱体积为100CC；测试面积为6.45cm2；样品面积＞6cm×6cm。
上述提及的支撑层孔隙的平均孔径采用下述方法测试得到：采用美国PMI公司的PMI多功能孔径分析仪对隔膜孔径进行测试，将待测试样品裁剪成直径为0.5cm的圆片，在浸润液中浸泡10min，用镊子将其转移到夹具中，压力范围设置为0-500PSI，进行孔径测试。
上述提及的隔膜的厚度采用下述方法测试得到：校准千分尺，然后将隔膜置于双砧之间，轻轻旋转套筒至出现响声，读数记录隔膜厚度。
隔膜中不含有支撑层时，上述提及的阻隔层的厚度采用下述方法测试得到：校准千分尺，然后将隔膜置于双砧之间，轻轻旋转套筒至出现响声，读数记录隔膜厚度。
隔膜中同时含有支撑层和阻隔层时，上述提及的阻隔层的厚度采用下述方法测试得到：首先校准千分尺，然后将隔膜置于双砧之间，轻轻旋转套筒至出现响声，读数记录隔膜厚度；取下隔膜，除去阻隔层得到支撑层，重复上述测定过程，测得支撑层的厚度；将隔膜的厚度减去支撑层的厚度，得到阻隔层的厚度。
上述提及的聚合物的重均分子量采用凝胶色谱法(GPC)进行测定。
三、隔膜性能测定
1.隔膜透气度
将隔膜平展，选取平整无油污的位置，放置在空气压缩筒出气口，旋紧固定；隔膜固定在工位后，用浮动在液体上的圆筒的自身重力来压缩筒内空气。随着空气通过试样，圆筒便会平稳下落。测量一定体积的空气，通过试样所需的时间，并按此计算透气度。其中，空气柱体积为100CC；测试面积为6.45cm2；样品面积＞6cm×6cm。结果详见表2。
四、二次电池的制备
1.正极极片的制备
将LNMO(LiNi0.5Mn1.5O4，作为正极活性材料)、导电炭黑(作为导电剂)和聚偏氟乙烯(作为粘合剂)按照质量比96:2.5:1.5混合，然后加入N-甲基吡咯烷酮搅拌，分散成正极浆料。将正极浆料涂布在铝箔的两侧表面上，干燥、冷压、分切，制得正极极片。其中，正极粉末单侧涂布单位面密度为0.02g/cm2。
2.负极极片的制备
将人造石墨(作为负极活性材料)、导电炭黑(作为导电剂)、丁苯橡胶(作为粘合剂)和羧甲基纤维素钠(作为增稠剂)按照质量比96:1:1:2混合，然后加入去离子水搅拌，分散成负极浆料。将负极浆料均匀涂覆在铜箔的一侧表面上，干燥、冷压、分切，制得负极极片。其中，负极粉末单侧涂布单位面密度为0.008g/cm2。
3.电解液的制备
正极电解液的制备：在充满氩气的手套箱(水分＜10ppm，氧分＜10ppm)中，向甲基三氟乙基碳酸酯(FEMC)中加入1wt％的硫酸亚乙烯酯和1wt％的丙磺酸内酯，充分混合，最后向混合溶液中加入六氟磷酸锂(LiPF6)至LiPF6的摩尔浓度为1mol/L，制得正极电解液。
负极电解液的制备：在充满氩气的手套箱(水分＜10ppm，氧分＜10ppm)中，将碳酸乙烯酯(EC)和碳酸甲乙酯(EMC)按质量比为EC：EMC＝7:3均匀混合，向混合液中加1wt％的碳酸亚乙烯酯和1wt％的氟代碳酸乙烯酯(FEC)，充分混合，最后向混合溶液中缓慢加入六氟磷酸锂(LiPF6)至LiPF6的摩尔浓度为1mol/L，制得负极电解液。
4.采用上述各实施例和对比例中的隔离膜。
5.电芯的制备
将正极极片、隔膜、负极极片按顺序叠好，使隔膜处于正、负极片之间起到隔离的作用，将三者放置于与隔离膜等长等宽的铝塑袋内，将除铝塑袋开口之前的其他三侧连同隔离膜一起热封，隔离膜和铝塑袋形成密度的正极腔室和负极腔室，，正极腔室侧注入正极电解液，负极腔室侧注入负极电解液，封口制得电芯，然后将电芯放入电池壳体中，化成，静置，制得二次电池。
五、二次电池性能测试
1.循环性能测试
在25℃下，分别将上述各实施例和对比例中二次电池以0.1C恒流充电至4.9V，然后以4.9V恒压充电至电流为0.05C；静置5min之后，将二次电池以0.1C恒流放电至3.5V，此为一个充放电循环过程，此次的放电容量为二次电池的初始放电容量。将二次电池按上述方法循环充放电，直至循环后的放电容量衰减为初始放电容量的80％，结束测试，记录此时二次电池的循环圈数。
2.存储性能测试
在25℃下，分别将上述各实施例和对比例中二次电池以0.1C恒流充电至4.9V，然后以4.9V恒压充电至电流为0.05C，此时二次电池处于满充状态。将满充状态的二次电池置于25℃环境中存储，每隔5天取出一次，并以0.1C恒流放电至3.5V，得到存储一段时间后的放电容量；之后将二次电池按照上述方式满充后再次置于25℃环境中存储，直至二次电池存储后的放电容量衰减为初始放电容量的70％，结束测试，记录二次电池总的存储天数。
3.阻抗测试
提取“1.循环性能测试”中首圈容量测试过程中，充电结束静置5min后电压为V1，提取0.1C放电30s的电压为V2，则循环初始阻抗为(V1-V2)/(0.1C)。
上述各实施例和对比例的性能测试结果如表2所示。
表2

由表2中实施例1-37的结果可知，通过调控阻隔材料的体积平均粒径Dv50以及阻隔层厚度，阻隔层的透气度≥300s/100mL，阻隔层可大幅度抑制电解液中溶剂、添加剂和副产物穿透，消除正极和负极交互引起的电池容量衰减。
实施例1-6的区别主要在于阻隔层厚度和阻隔材料的体积平均粒径Dv50的比例不同，实施例6中两者比例最大；与实施例1-5相比，实施例6中循环圈数及存储天数分别显著降低，循环阻抗显著增大。推测可能是由于d1/D过大时，有可能会导致阻隔材料颗粒之间的堆叠过于紧密，阻隔材料颗粒相互之间接触面过多，从而可能减慢锂离子经由阻隔材料的传输速度。
实施例3、实施例7-12的区别在于阻隔材料内部孔隙的孔径不同，实施例12中阻隔材料内部孔隙的孔径最大。与实施例3以及实施例7-11相比，实施例12中循环圈数及存储天数显著降低。 推测可能是由于阻隔材料内部孔隙的孔径过大时，隔膜的阻隔作用减弱，从而可能使得电解液中除锂离子之外的部分其他物质也可穿透隔膜。
与实施例14、实施例16-17及实施例19-21相比，实施例15中二次电池的循环阻抗显著增大；推测可能是由于LLZO的电导率太差，导致二次电池的阻抗增大。
与实施例14、实施例16-17及实施例19-21相比，实施例18中二次电池的循环阻抗显著增大；推测可能是由于阻隔层厚度与阻隔材料体积平均粒径Dv50的比值过大，导致二次电池的阻抗显著增大。
实施例3、实施例24-30的区别在于阻隔材料在阻隔层中的面积占比以及聚合物层在阻隔层中的质量占比不同，实施例28中阻隔材料在阻隔层中的面积占比最小。与实施例3、实施例24-27以及实施例29-30相比，实施例28中二次电池的循环圈数明显减少，阻抗显著增大；推测可能是由于阻隔材料在阻隔层中的单位面积占比过低时，可能会导致锂离子传输通道减少，恶化电池阻抗，同时降低其循环性能和存储性能。
实施例3、实施例31-34的区别在于聚合物的重均分子量不同。实施例31中聚合物的重均分子量最小。与实施例3及实施例32-34相比，实施例31中循环圈数和存储天数明显减少；推测可能是聚合物的重均分子量过低时，形成的阻隔层致密性较差，可能阻隔层的阻隔作用减弱，电解液中除锂离子之外的部分其他物质也可穿透隔膜。
由实施例1-37和对比例1的结果可知，与普通隔膜相比，本申请的隔膜的透气度显著降低；采用本申请的隔膜形成的二次电池，其循环圈数和存储天数显著提高。表明本申请的隔膜大幅度抑制了电解液中溶剂、添加剂和副产物穿过阻隔层，消除正极和负极交互引起的电池容量衰减，提高其循环性能和存储性能。
由实施例1和对比例2的结果可知，阻隔层的透气度低于300s/100mL时，可能导致阻隔层对于正极和负极之间的交互抑制作用减弱。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到各种等效的修改或替换，这些修改或替换都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (20)

  1. 一种隔膜，包括阻隔层，所述阻隔层包括聚合物层和至少部分嵌入所述聚合物层中的阻隔材料；
    其中，所述阻隔材料包括微介孔材料和导离子无机材料中的一种或多种；所述阻隔材料的体积平均粒径Dv50记为D，所述阻隔层的厚度记为d1，所述阻隔材料的体积平均粒径Dv50和所述阻隔层的厚度满足：0.2≤d1/D≤1000；
    所述阻隔层的透气度≥300s/100mL。
  2. 如权利要求1所述的隔膜，其中所述阻隔层的透气度≥500s/100mL；可选地，所述阻隔层的透气度≥800s/100mL。
  3. 如权利要求1至2任一项所述的隔膜，其中所述阻隔材料的体积平均粒径Dv50和所述阻隔层的厚度满足：1≤d1/D≤500；可选为1≤d1/D≤300。
  4. 如权利要求1至3任一项所述的隔膜，其中所述阻隔材料的体积平均粒径Dv50满足：0.005μm≤D≤10μm；可选为0.007μm≤D≤5μm；进一步可选为0.01μm≤D≤1μm。
  5. 如权利要求1至4任一项所述的隔膜，其中所述阻隔层的厚度满足：0.007μm≤d1≤50μm；可选为0.2μm≤d1≤15μm。
  6. 如权利要求1至5任一项所述的隔膜，其中所述微介孔材料包括共价有机框架材料和金属有机骨架材料中的一种或多种；
    可选地，聚合形成所述共价有机框架材料的单体之间的连接基团包括环硼氧基、-C＝N-、三嗪基团、-C＝N-N＝C-、-C＝C-、-CO-NH-、-C＝N-NH-CO-和咪唑基团中的一种或几种。
  7. 如权利要求1至6任一项所述的隔膜，其中所述导离子无机材料包括LLZO、LLTO、LATP、LAGP、LSPS，以及上述物质的包覆物、掺杂物和/或带有包覆层的掺杂物中的一种或多种。
  8. 如权利要求6至7任一项所述的隔膜，其中所述微介孔材料的内部孔隙的孔径记为d2，所述微介孔材料的内部孔隙的孔径满足：0.04nm≤d2≤5nm；可选为0.3nm≤d2≤2nm。
  9. 如权利要求6至8任一项所述的隔膜，其中在25℃时所述导离子无机材料的电导率≥0.0001mS·cm-1；
    可选地，在25℃时所述导离子无机材料的电导率≥0.001mS·cm-1；
    进一步可选地，在25℃时所述导离子无机材料的电导率≥0.01mS·cm-1。
  10. 如权利要求1至9任一项所述的隔膜，其中所述阻隔材料在所述阻隔层中的面积占比为30％-99％；可选为50％-99％；进一步可选为70％-99％。
  11. 如权利要求1至10任一项所述的隔膜，其中所述聚合物层具有如下(1)-(3)项特征中的至少一项：
    (1)所述聚合物层包括溶胀度≤10％的聚合物；
    可选地，所述聚合物包括聚乙烯、聚丙烯、聚酰亚胺和聚偏二氟乙烯中的一种或多种；
    (2)所述聚合物层在所述阻隔层中的质量占比≤50％；
    可选地，所述聚合物层在所述阻隔层中的质量占为2％-30％；进一步可选为5％-15％；
    (3)所述聚合物层包括重均分子量为1W-200W的聚合物；
    可选地，所述聚合物层包括重均分子量为2W-150W的聚合物；
    进一步可选地，所述聚合物层包括重均分子量为10W-100W的聚合物。
  12. 如权利要求1至11任一项所述的隔膜，其中所述隔膜还包括支撑层，所述阻隔层位于所述支撑层的至少一侧。
  13. 如权利要求12所述的隔膜，其中所述支撑层具有如下(1)-(3)项特征中的至少一项：
    (1)所述支撑层具有孔隙，所述支撑层的孔隙的平均孔径为20nm-1000nm；可选为100nm-500nm；
    (2)所述支撑层的原料包括聚乙烯、聚丙烯、聚酰亚胺和聚偏二氟乙烯中的一种或多种。
  14. 如权利要求12至13任一项所述的隔膜，其中所述隔膜的厚度为2μm-12μm；可选为3μm-10μm；进一步可选为5μm-7μm。
  15. 如权利要求1至14任一项所述的隔膜，其中所述隔膜具有下述特征中的至少一项：
    (1)所述隔膜的透气度≥300s/100mL；可选地，所述隔膜的透气度≥500s/100mL；进一步可选地，所述隔膜的透气度≥800s/100mL；
    (2)所述隔膜的拉伸强度≥1000MPa；可选地，所述隔膜的拉伸强度≥1200MPa；进一步可选地，所述隔膜的拉伸强度≥1500MPa。
  16. 一种二次电池，包括正极极片、负极极片、正极电解液、负极电解液以及如权利要求1至15任一项所述的隔离膜；
    所述隔离膜位于所述正极极片和所述负极极片之间，所述正极电解液位于所述正极极片和所述隔离 膜之间，所述负极电解液位于所述负极极片和所述隔离膜之间；所述正极电解液和所述负极电解液中含有的溶剂、锂盐和添加剂中的一项或多项是不同的。
  17. 如权利要求16所述的二次电池，其中所述正极电解液的溶剂和所述负极电解液的溶剂不同；
    可选地，所述正极电解液的溶剂包括碳酸酯类溶剂、氟代碳酸酯类溶剂、氟代羧酸酯类溶剂、砜类溶剂、氟代砜类溶剂、磷酸酯类溶剂、硼酸酯类溶剂和腈类溶剂中的一种或多种；
    可选地，所述负极电解液的溶剂包括碳酸酯类溶剂、羧酸酯类溶剂、醚类溶剂、氟代羧酸酯类溶剂和氟代碳酸酯类溶剂中的一种或多种。
  18. 如权利要求17所述的二次电池，其中所述氟代碳酸酯类溶剂包括甲基三氟乙基碳酸酯、二(三氟甲基)碳酸酯、二(三氟乙基)碳酸酯、4-三氟甲基碳酸乙烯酯、双氟代碳酸乙烯酯、三氟甲基三氟乙基碳酸酯、三氟丙基碳酸酯和2,2-二氟乙基甲基碳酸酯中的一种或多种；
    所述氟代羧酸酯类溶剂包括3,3,3-三氟乙酸三氟乙酯、乙酸2,2-二氟乙酯、二氟乙酸乙酯和乙酸2,2,2-三氟乙酯中的一种或多种；
    所述砜类溶剂包括环丁砜、二甲基砜、二乙基砜、甲基乙基砜、甲基异丙基砜、二甲基亚砜、二乙基亚砜和甲基乙基亚砜中的一种或多种；
    所述氟代砜类溶剂包括甲基三氟甲基砜、乙基三氟甲基砜、丙基三氟甲基砜、甲基三氟乙基砜、甲基三氟丙基砜、1,1,2,2-四氟丙基甲基砜、三氟甲基异丙基砜和甲基六氟异丙基砜中的一种或多种；
    所述磷酸酯类溶剂包括磷酸三甲酯、磷酸三乙酯、磷酸三丙酯、磷酸异丙基酯、磷酸三(六氟异丙基)酯和磷酸三(2,2,2-三氟乙基)酯中的一种或多种；
    所述硼酸酯类溶剂包括硼酸三甲酯、硼酸三乙酯、硼酸三(六氟异丙基)酯和硼酸三(2,2,2-三氟乙基)酯中的一种或多种；
    所述腈类溶剂包括乙腈、琥珀腈、丁二腈、戊二腈、己二腈、1,4-二氰基-2-丁烯、1,3,6-己烷三腈、乙二醇双丙腈醚和1,2,3-三氰乙氧基中的一种或多种；
    所述碳酸酯类溶剂包括碳酸二甲酯、碳酸二乙酯、碳酸甲乙酯和碳酸乙烯酯中的一种或多种；
    所述羧酸酯类溶剂包括甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯和丙酸丙酯中的一种或多种；
    所述醚类溶剂包括1,2-二甲氧基乙烷、四乙醇二甲醚、γ-丁内酯和四氢呋喃中的一种或多种。
  19. 如权利要求16-18任一项所述的二次电池，其中所述正极电解液的锂盐和所述负极电解液的锂盐不同；
    可选地，所述正极电解液的锂盐包括六氟磷酸锂、四氟硼酸锂、双氟磺酰亚胺锂和二草酸硼酸锂中的一种或多种；
    可选地，所述负极电解液的锂盐包括六氟磷酸锂、四氟硼酸锂、双氟磺酰亚胺锂和二草酸硼酸锂中的一种或多种。
  20. 一种用电装置，包括如权利要求16-19任一项所述的二次电池。
PCT/CN2023/077202 2023-02-20 2023-02-20 隔膜、二次电池及用电装置 WO2024174066A1 (zh)

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