WO2022120826A1 - 一种电化学装置和电子设备 - Google Patents

一种电化学装置和电子设备 Download PDF

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Publication number
WO2022120826A1
WO2022120826A1 PCT/CN2020/135869 CN2020135869W WO2022120826A1 WO 2022120826 A1 WO2022120826 A1 WO 2022120826A1 CN 2020135869 W CN2020135869 W CN 2020135869W WO 2022120826 A1 WO2022120826 A1 WO 2022120826A1
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Prior art keywords
coating
electrochemical device
coating layer
inorganic particles
current collector
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PCT/CN2020/135869
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English (en)
French (fr)
Inventor
江兵
黄须啟
周丰
刘涛
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Dongguan Amperex Technology Ltd
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Dongguan Amperex Technology Ltd
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Priority to KR1020237019903A priority Critical patent/KR20230097199A/ko
Priority to EP20964762.7A priority patent/EP4207426A4/en
Priority to JP2023535493A priority patent/JP7731427B2/ja
Priority to CN202080009473.1A priority patent/CN114930600A/zh
Priority to PCT/CN2020/135869 priority patent/WO2022120826A1/zh
Publication of WO2022120826A1 publication Critical patent/WO2022120826A1/zh
Priority to US18/194,019 priority patent/US20230261201A1/en
Anticipated expiration legal-status Critical
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    • 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
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. coatings
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H01M4/623—Binders being polymers fluorinated polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/668—Composites of electroconductive material and synthetic resins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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 relates to the technical field of electrochemistry, and in particular, to an electrochemical device and an electronic device.
  • the active material of the negative electrode is easy to fall off the surface of the electrode. For example, it is easy to cause decarburization after cold pressing, which reduces the battery capacity.
  • the volume of the negative electrode material will change. As a result, the negative electrode material may fall off from the surface of the pole piece, resulting in a potential safety hazard.
  • a conductive layer is often applied on the surface of the current collector to alleviate the decarburization of the pole piece, but the existing conductive layer is often thicker, resulting in loss of energy density.
  • the number of effective bonding points with the conductive layer is limited, and the decarburization phenomenon will still occur after the battery is cycled for a long time. Therefore, it is urgent to find a new way to improve the viscosity of the pole piece and reduce the shedding of the negative electrode active material.
  • the purpose of the present application is to provide an electrochemical device, which can improve the bonding force between the negative electrode active material and the pole piece in the negative electrode pole piece by arranging a suitable coating between the active material layer of the negative electrode and the current collector.
  • a first aspect of the present application provides an electrochemical device, comprising a negative electrode, the negative electrode comprising a current collector, a first coating layer and a second coating layer, the second coating layer is provided on at least one surface of the current collector, The first coating is disposed between the current collector and the second coating, wherein the first coating includes inorganic particles, and the peeling force between the first coating and the second coating F is: 15N ⁇ F ⁇ 30N.
  • the particle size Dv50 of the inorganic particles satisfies 50 nm ⁇ Dv50 ⁇ 1 ⁇ m.
  • the Mohs hardness of the inorganic particles is 2.5 to 7.5.
  • the inorganic particles include at least one of boehmite, aluminum powder, quartz sand, apatite, nano-ceramic or zircon.
  • the first coating further includes a conductive agent, a binder and a dispersing agent, and based on the total mass of the first coating, the inorganic particles, the binding agent
  • the mass percentage of the agent, the conductive agent and the dispersing agent is (2%-10%): (30%-60%): (30%-60%): (2%-5%).
  • the binder includes styrene-butadiene rubber, polyacrylic acid, polyvinyl alcohol, polyethylene glycol, polyacrylate, polyacrylonitrile, polyvinylidene fluoride, polyvinyl chloride , at least one of formaldehyde resin, cyclodextrin or cyanoacrylate.
  • the dispersing agent comprises sodium hydroxymethyl cellulose, lithium hydroxymethyl cellulose, sodium alginate, propylene glycol alginate, methyl cellulose, sodium starch phosphate, At least one of sodium carboxymethylcellulose, sodium alginate, casein, sodium polyacrylate, polyoxyethylene or polyvinylpyrrolidone.
  • the conductive agent includes at least one of a zero-dimensional conductive agent or a one-dimensional conductive agent.
  • the zero-dimensional conductive agent includes at least one of conductive carbon black, acetylene black or Ketjen black, and the Dv50 of the zero-dimensional conductive agent is 50 nm to 1 ⁇ m;
  • the one-dimensional conductive agent includes at least one of a conductive carbon tube or a conductive carbon rod, and the one-dimensional conductive agent has an average diameter of 50 nm to 1 ⁇ m.
  • the thickness L of the first coating layer satisfies: 100 nm ⁇ L ⁇ 2 ⁇ m.
  • the coating weight X of the first coating layer satisfies: 0.02 mg/cm 2 ⁇ X ⁇ 0.15 mg/cm 2 .
  • the coverage of the first coating is 50% to 100%.
  • the peeling force between the first coating and the current collector is 10 N/m to 300 N/m.
  • the resistance of the negative electrode is 1 m ⁇ to 100 m ⁇ .
  • a second aspect of the present application provides an electronic device, including the electrochemical device provided in the first aspect of the present application.
  • a first coating layer is provided between the current collector of the negative electrode and the second coating layer, the first coating layer contains inorganic particles, and the inorganic particles are wrapped by a binder to form a higher-strength bonding unit , on the one hand, the formation of the bonding unit increases the bonding strength and bonding sites of the first coating, thereby effectively improving the bonding force between the current collector and the second coating;
  • the junction unit can increase the cohesive force of the first coating layer, and the cohesion force can offset the tensile stress of part of the current collector, thereby increasing the strength of the current collector, so that the current collector is not easily broken during processing.
  • the first coating increases the bonding force between the second coating and the current collector, the content of the binder in the second coating can be reduced, and the proportion of the negative active material in the negative electrode can be increased, thereby Improve the energy density of lithium-ion batteries.
  • FIG. 1 is a schematic structural diagram of a negative pole piece.
  • a first aspect of the present application provides an electrochemical device, as shown in FIG. 1 , comprising a negative electrode, wherein the negative electrode includes a current collector 1 , a first coating 2 and a second coating 3 , and the second coating 3 is provided On at least one surface of the current collector 1, the first coating layer 2 is disposed between the current collector 1 and the second coating layer 3, wherein the first coating layer 2 includes inorganic particles, so The peeling force F between the first coating 2 and the second coating 3 is: 15N ⁇ F ⁇ 30N.
  • the second coating layer 3 can be a negative electrode active material layer.
  • the inventor found in research that when inorganic particles are added to the first coating layer 2, the first coating layer 2 and the second coating layer can be significantly increased.
  • the peeling force between the layers 3 is not limited to any theory. The inventor believes that this is because the inorganic particles are wrapped by the binder to form a higher-strength bonding unit, which increases the active material in the second coating 3 and the first coating. 2 between bond strength and bond sites.
  • the peeling force between the first coating layer of the negative electrode pole piece of the present application and the negative electrode active material layer can reach 15N to 30N, wherein, in the prior art, the peeling force between the negative electrode active material layer and the current collector or the adhesive coating layer is difficult to reach more than 10N , in the negative pole piece of the present application, the peeling force between the negative electrode active material layer and the pole piece is obviously higher than that of the existing negative pole piece.
  • the current collector of the present application may have a first coating and a second coating on one surface thereof, or may have a first coating and a second coating on both surfaces thereof. Personnel can choose according to actual needs.
  • the particle size Dv50 of the inorganic particles satisfies 50 nm ⁇ Dv50 ⁇ 1 ⁇ m.
  • the inventor found in the research that the average particle size Dv50 of the inorganic particles is greater than 50nm, which can avoid the agglomeration of the inorganic particles; the average particle size Dv50 of the inorganic particles is greater than 1 ⁇ m, which will make the surface of the first coating uneven and affect the performance of lithium-ion batteries. play.
  • the average particle size Dv50 of the inorganic particles within the above range, on the one hand, it can ensure that the thickness of the first coating does not increase the thickness of the negative electrode, thereby avoiding the loss of the volume energy density of the lithium-ion battery, and on the other hand, it can ensure that the first coating thickness does not increase the thickness of the negative electrode.
  • the flatness of the coating surface avoids affecting the performance of the lithium-ion battery.
  • the Mohs hardness of the inorganic particles is 2.5-7.5.
  • the inventor found in the research that the hardness of the inorganic particles is too small, and the cold pressing process is easy to deform, resulting in the deterioration of the stability of the internal structure of the first coating layer, which affects the strength of the bonding unit formed by the inorganic particles and the binder; If the hardness is too large, the wear and tear of the coating equipment will be large.
  • the types of inorganic particles are not particularly limited, as long as the Mohs hardness is within the range of 2.5 to 7.5, and the purpose of the present application can be achieved.
  • the inorganic particles may include at least one of boehmite, aluminum powder, quartz sand, apatite, nano-ceramic or zircon, wherein the Mohs hardness of zircon is about 7.5, and the Mohs hardness of quartz sand is about 7.5.
  • the hardness is about 7, the Mohs hardness of nano-ceramic is about 6, the Mohs hardness of boehmite is about 3, the Mohs hardness of aluminum powder is 2.75, and the Mohs hardness of apatite is 5.
  • the inventors found that the inorganic particles of the present application have high compatibility with organic substances and are easy to disperse, so they are more suitable as additives for the first coating layer 2 .
  • the first coating further includes a conductive agent, a binder and a dispersing agent, and based on the total mass of the first coating, the inorganic particles, the binding agent
  • the mass percentage of the agent, the conductive agent and the dispersant is (2%-10%):(30%-60%):(30%-60%):(2%-5%).
  • the proportion of the mass of inorganic particles to the total mass of the first coating is greater than 10% %, the phenomenon that inorganic particles are difficult to disperse and particles agglomerate easily, and the internal resistance of the pole piece will also increase; by controlling the quality of the dispersant to 2% to 5% of the total mass of the first coating, the The internal structure of the coating is uniform and stable, which can effectively prevent the agglomeration of inorganic particles; when the proportion of the mass of the binder to the total mass of the first coating is less than 30%, the bonding effect is not obvious; when the mass of the binder accounts for the first coating When the proportion of the total mass of the layer is more than 60%, the binder content is too much, which is easy to cause the agglomeration of inorganic particles; by controlling the quality of the conductive agent to be 30% to 60% of the total mass of the first coating, the conductivity of the negative electrode can be improved. .
  • the type of the binder is not particularly limited as long as the purpose of the present application can be achieved.
  • the binder may include at least one of styrene-butadiene rubber, polyacrylic acid, polyvinyl alcohol, polyethylene glycol, polyvinylidene fluoride, polyvinyl chloride, formaldehyde resin, cyclodextrin, cyanoacrylate, and the like.
  • the addition of the binder can improve the viscosity of the first coating layer, thereby increasing the binding force between the first coating layer and the negative electrode current collector, and between the first coating layer and the second coating layer respectively, and can also reduce the concentration of the second coating layer. Binder content.
  • the type of dispersant is not particularly limited as long as the purpose of the present application can be achieved.
  • the dispersing agent may comprise sodium carboxymethyl cellulose, lithium hydroxymethyl cellulose, sodium alginate, propylene glycol alginate, methyl cellulose, sodium starch phosphate, sodium carboxymethyl cellulose, sodium alginate , at least one of casein, sodium polyacrylate, polyoxyethylene or polyvinylpyrrolidone.
  • the addition of the dispersant can improve the uniformity and stability of the internal structure of the first coating layer and prevent the agglomeration of inorganic particles.
  • the conductive agent may include at least one of a zero-dimensional conductive agent and a one-dimensional conductive agent.
  • the types of zero-dimensional conductive agent and one-dimensional conductive agent are not particularly limited, as long as the purpose of the application can be achieved.
  • the zero-dimensional conductive agent may include conductive carbon black, acetylene black, superconducting carbon black, particle At least one of graphite or Ketjen black, etc.
  • the average particle size Dv50 of the zero-dimensional conductive agent is 50nm to 1 ⁇ m
  • the one-dimensional conductive agent can include at least one of conductive carbon tubes or conductive carbon rods, etc.
  • the average diameter is 50 nm to 1 ⁇ m.
  • the thickness L of the first coating layer 2 satisfies: 100 nm ⁇ L ⁇ 2 ⁇ m; optionally, 200 nm ⁇ L ⁇ 1 ⁇ m.
  • the coating weight X of the first coating layer 2 satisfies: 0.02mg/cm 2 ⁇ X ⁇ 0.15mg/cm 2 .
  • the coverage of the first coating on the current collector is 50% to 100%.
  • the coverage rate of the first coating is 50% to 100%.
  • the peeling force between the first coating 2 and the current collector 1 is 10 N/m to 300 N/m.
  • the resistance of the negative electrode sheet is 1 m ⁇ to 100 m ⁇ .
  • the current collector is not particularly limited, and negative electrode current collectors known in the art, such as copper foil, aluminum foil, aluminum alloy foil, and composite current collector, can be used.
  • the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material is not particularly limited, and a negative electrode active material known in the art can be used.
  • at least one of artificial graphite, natural graphite, mesocarbon microspheres, silicon, silicon carbon, silicon oxide, soft carbon, hard carbon, lithium titanate or niobium titanate, and the like may be included.
  • the thicknesses of the negative electrode current collector and the negative electrode active material layer are not particularly limited as long as the purpose of the present application can be achieved.
  • the thickness of the negative electrode current collector is 6 ⁇ m to 10 ⁇ m, and the thickness of the negative electrode active material layer is 30 ⁇ m to 120 ⁇ m.
  • the positive electrode in the present application is not particularly limited as long as the purpose of the present application can be achieved.
  • a positive electrode typically includes a positive electrode current collector and a positive electrode active material layer.
  • the positive electrode current collector is not particularly limited, and can be a positive electrode current collector known in the art, such as copper foil, aluminum foil, aluminum alloy foil, and composite current collector.
  • the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material is not particularly limited, and can be a positive electrode active material known in the art, for example, including nickel cobalt lithium manganate (811, 622, 523, 111), nickel cobalt lithium aluminate, At least one of lithium iron phosphate, lithium-rich manganese-based material, lithium cobaltate, lithium manganate, lithium iron manganese phosphate, or lithium titanate.
  • the thicknesses of the positive electrode current collector and the positive electrode active material layer are not particularly limited as long as the purpose of the present application can be achieved.
  • the thickness of the positive electrode current collector is 8 ⁇ m to 12 ⁇ m
  • the thickness of the positive electrode active material layer is 30 ⁇ m to 120 ⁇ m.
  • the positive electrode may further comprise a conductive layer located between the positive electrode current collector and the positive electrode active material layer.
  • the composition of the conductive layer is not particularly limited, and may be a conductive layer commonly used in the art.
  • the conductive layer includes a conductive agent and a binder.
  • the lithium ion battery of the present application further includes a separator for separating the positive electrode and the negative electrode, preventing the internal short circuit of the lithium ion battery, allowing the free passage of electrolyte ions, and completing the role of the electrochemical charging and discharging process.
  • the separator is not particularly limited as long as the purpose of the present application can be achieved.
  • PET polyethylene terephthalate
  • cellulose films such as polyethylene terephthalate (PET) films
  • PET polyamide Imine film
  • PA polyamide film
  • spandex or aramid film woven film
  • non-woven film non-woven film (non-woven fabric)
  • microporous film composite film, diaphragm paper, laminated film, spinning film, etc. at least one of them.
  • the release film may include a substrate layer and a surface treatment layer.
  • the substrate layer can be a non-woven fabric, film or composite film with a porous structure, and the material of the substrate layer can include at least one of polyethylene, polypropylene, polyethylene terephthalate, polyimide, etc. kind.
  • polypropylene porous membranes, polyethylene porous membranes, polypropylene non-woven fabrics, polyethylene non-woven fabrics, or polypropylene-polyethylene-polypropylene porous composite membranes may be used.
  • at least one surface of the substrate layer is provided with a surface treatment layer, and the surface treatment layer can be a polymer layer or an inorganic layer, or a layer formed by mixing a polymer and an inorganic substance.
  • the inorganic substance layer includes inorganic particles and a binder
  • the inorganic particles are not particularly limited, for example, can be selected from aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, nickel oxide, At least one of zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium sulfate, and the like.
  • the binder is not particularly limited, for example, it can be selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyethylene pyrrolidine One or a combination of ketone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene and polyhexafluoropropylene.
  • the polymer layer contains a polymer, and the material of the polymer includes polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polyvinylidene fluoride or poly( At least one of vinylidene fluoride-hexafluoropropylene) and the like.
  • the lithium ion battery of the present application further includes an electrolyte, and the electrolyte may be one or more of a gel electrolyte, a solid electrolyte, and an electrolyte, and the electrolyte includes a lithium salt and a non-aqueous solvent.
  • the lithium salt is selected from LiPF 6 , LiBF 4 , LiAsF 6 , LiClO 4 , LiB(C 6 H 5 ) 4 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiN(SO 3 ) One or more of 2 CF 3 ) 2 , LiC(SO 2 CF 3 ) 3 , LiSiF 6 , LiBOB, and lithium difluoroborate.
  • LiPF 6 can be chosen as the lithium salt because it can give high ionic conductivity and improve cycle characteristics.
  • the non-aqueous solvent may be a carbonate compound, a carboxylate compound, an ether compound, other organic solvents, or a combination thereof.
  • the above-mentioned carbonate compound may be a chain carbonate compound, a cyclic carbonate compound, a fluorocarbonate compound, or a combination thereof.
  • Examples of the above-mentioned chain carbonate compound are dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), carbonic acid Methyl ethyl ester (MEC) and combinations thereof.
  • Examples of cyclic carbonate compounds are ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylethylene carbonate (VEC), and combinations thereof.
  • fluorocarbonate compounds are fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate Ethyl carbonate, 1,1,2,2-tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-dicarbonate Fluoro-1-methylethylene, 1,1,2-trifluoro-2-methylethylene carbonate, trifluoromethylethylene carbonate, and combinations thereof.
  • FEC fluoroethylene carbonate
  • 1,2-difluoroethylene carbonate 1,1-difluoroethylene carbonate
  • 1,1,2-trifluoroethylene carbonate Ethyl carbonate 1,1,2,2-tetrafluoroethylene carbonate
  • 1-fluoro-2-methylethylene carbonate 1-fluoro-1-methylethylene carbonate
  • 1,2-dicarbonate Fluoro-1-methylethylene 1,1,2-trifluoro-2-methylethylene carbonate, trifluoromethyl
  • carboxylate compounds are methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, ⁇ -butyrolactone , caprolactone, valerolactone, mevalonolactone, caprolactone, and combinations thereof.
  • ether compounds examples include dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethyl ether Oxyethane, 2-methyltetrahydrofuran, tetrahydrofuran, and combinations thereof.
  • Examples of the above-mentioned other organic solvents are dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, Formamide, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, and phosphate esters and combinations thereof.
  • electrochemical devices can be manufactured by the following process: the positive electrode and the negative electrode are overlapped through a separator, and they are wound, folded, etc., as required, and placed in a case, and the electrolyte is injected into the case and sealed.
  • an overcurrent preventing element, a guide plate, etc. may be placed in the case to prevent pressure rise and overcharge and discharge inside the electrochemical device.
  • a second aspect of the present application provides an electronic device comprising the electrochemical device provided in the first aspect of the present application.
  • the electronic device of the present application is not particularly limited, and it can be used in any electronic device known in the prior art.
  • electronic devices may include, but are not limited to, notebook computers, pen input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, video recorders , LCD TV, Portable Cleaner, Portable CD Player, Mini CD, Transceiver, Electronic Notepad, Calculator, Memory Card, Portable Recorder, Radio, Backup Power, Motor, Automobile, motorcycle, Power-assisted Bicycle, Bicycle, Lighting Appliances, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.
  • the average particle size Dv50 of the inorganic particles was measured using a Malvern laser particle sizer MS3000.
  • Dv50 refers to the particle size at which the inorganic particles reach 50% of the cumulative volume from the small particle size side in the volume-based particle size distribution, that is, the volume of the inorganic particles smaller than this particle size accounts for 50% of the total volume of the inorganic particles.
  • step (1) Stick the pole piece sample intercepted in step (1) on the double-sided tape with the test surface facing down;
  • step (1) Stick the pole piece sample intercepted in step (1) on the double-sided tape with the test surface facing down;
  • the test temperature is 25/45°C, charge to 4.4V with 0.7C constant current, charge to 0.025C with constant voltage, and discharge to 3.0V with 0.5C after standing for 5 minutes.
  • the capacity obtained in this step was taken as the initial capacity, and 0.7C charge/0.5C discharge was carried out for cycle test, and the capacity decay curve was obtained by taking the ratio of the capacity in each step to the initial capacity.
  • the room temperature cycle performance of the lithium-ion battery was recorded as the number of cycles from 25°C to 90% of the capacity retention rate, and the high-temperature cycle performance of the lithium-ion battery was recorded as the number of cycles from 45°C to 80%.
  • the cycle performance of the material is obtained by the number of cycles in this case.
  • discharge at 0.2C to 3.0V let stand for 5 minutes, charge at 0.5C to 4.45V, charge at constant voltage to 0.05C, and then let stand for 5 minutes, adjust the discharge rate, respectively, at 0.2C, 0.5C, 1C , 1.5C, 2.0C for discharge test, respectively, to obtain the discharge capacity, compare the capacity obtained at each rate with the capacity obtained at 0.2C, and compare the rate performance by comparing the ratio of 2C and 0.2C.
  • the prepared first coating slurry was coated on the surface of the negative electrode current collector copper foil to obtain a first coating with a thickness of 380 nm, the coverage of the first coating was 90%, and the coating weight of the first coating was 0.08 mg /cm 2 ;
  • the negative electrode active material graphite, styrene-butadiene polymer and sodium carboxymethyl cellulose are mixed according to the weight ratio of 97.5:1.3:1.2, and deionized water is added as a solvent to prepare a slurry with a solid content of 70%. and stir well.
  • the slurry was uniformly coated on the first coating layer, dried at 110°C, and cold-pressed to obtain a negative electrode pole piece with a negative electrode active material layer thickness of 150 ⁇ m coated on one side with the first coating layer and the negative electrode active material layer.
  • the same method is used to complete these steps on the back of the negative pole piece, that is, a negative pole piece with double-sided coating is obtained.
  • the negative pole pieces are cut into sheets with a size of 76mm ⁇ 851mm, and the tabs are welded for use.
  • the positive active material lithium cobalt oxide (LiCoO 2 ), conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) were mixed in a weight ratio of 97.5:1.0:1.5, and N-methylpyrrolidone (NMP) was added as a solvent. , prepare a slurry with a solid content of 75%, and stir evenly. The slurry was uniformly coated on one surface of a positive electrode current collector aluminum foil with a thickness of 10 ⁇ m, and dried at 90° C. to obtain a positive electrode sheet with a coating thickness of 110 ⁇ m. After the above steps are completed, the single-side coating of the positive electrode sheet is completed. After that, the above steps are repeated on the other surface of the positive electrode sheet to obtain a positive electrode sheet coated with positive active material on both sides. After the coating is completed, the pole piece is cut into a size of 38mm ⁇ 58mm for use.
  • NMP N-methylpyrrolidone
  • Lithium hexafluorophosphate is dissolved and mixed uniformly to obtain an electrolyte solution with a lithium salt concentration of 1.15 mol/L.
  • Alumina and polyvinylidene fluoride were mixed in a mass ratio of 90:10 and dissolved in deionized water to form a ceramic slurry with a solids content of 50%. Then, the ceramic slurry was uniformly coated on one side of the porous substrate (polyethylene, thickness 7 ⁇ m, average pore size 0.073 ⁇ m, porosity 26%) by gravure coating, and dried to obtain a ceramic coating
  • the bilayer structure with the porous substrate, the thickness of the ceramic coating is 50 ⁇ m.
  • PVDF Polyvinylidene fluoride
  • polyacrylate was mixed in a mass ratio of 96:4 and dissolved in deionized water to form a polymer slurry with a solids content of 50%. Then, the polymer slurry is uniformly coated on both surfaces of the above-mentioned double-layer structure of the ceramic coating layer and the porous substrate by the gravure coating method, and is subjected to drying treatment to obtain a separator, wherein the single layer formed by the polymer slurry is The coating thickness is 2 ⁇ m.
  • the above-prepared positive electrode, separator, and negative electrode are stacked in sequence, so that the separator is in the middle of the positive and negative electrodes for isolation, and the electrode assembly is obtained by winding.
  • the electrode assembly is put into an aluminum-plastic film packaging bag, and the moisture is removed at 80 ° C, the prepared electrolyte is injected, and the lithium ion battery is obtained through the processes of vacuum packaging, standing, forming, and shaping.
  • Example 2 The rest is the same as Example 1 except that the quartz sand is replaced by boehmite.
  • Example 3 Except that the carbon nanotubes were replaced with conductive carbon black, and the coating weight was adjusted to 0.02 mg/cm 2 , the rest was the same as that of Example 3.
  • Example 12 Except that the coating weights were adjusted to 0.05 mg/cm 2 , 0.08 mg/cm 2 , 0.1 mg/cm 2 , 0.13 mg/cm 2 , and 0.15 mg/cm 2 , the rest was the same as that of Example 12.
  • the rest is the same as that of Example 27.
  • Example 3 The rest is the same as in Example 3, except that the coverage of the first coating is adjusted to 100%, 80%, 70%, 60%, and 50%, respectively.
  • Example 3 The rest is the same as Example 3, except that the boehmite is replaced by alumina.
  • Example 12 Except that the coating weights were adjusted to 0.01 mg/cm 2 and 0.16 mg/cm 2 , the rest was the same as that of Example 12.
  • Example 27 Except for adjusting the thickness of the first coating to 2100 nm and 50 nm, the rest is the same as that of Example 27.
  • the peeling force between the first coating and the second coating of the negative pole piece is significantly improved, and both can reach more than 15N. Due to the improvement of the adhesion force of the pole piece, the rate performance and cycle performance of the battery are improved. also increased accordingly.
  • the pole piece has a higher adhesive force, and the peeling force between the first coating and the second coating can reach more than 20N .
  • the content of inorganic particles is 2% to 5%.
  • the mass content of the binder is in the range of 30% to 60%, the content of the conductive agent is in the range of 60% to 30%, and the mass content of the dispersant is in the range of 2 to 5%, the first The peeling force between the first coating and the second coating is greater than 15N, and the peeling force between the first coating and the second coating increases with the increase of the binder content; The content of the conductive agent gradually decreased. It can be seen from Example 11 that with the decrease of the content of the conductive agent, although the adhesion force of the pole piece increased, the rate discharge performance and cycle performance of the battery decreased. Therefore, in this application In some embodiments, the mass content of the binder is 30% to 60%, and the content of the conductive agent is 30% to 60%.
  • the coating weight of the first coating affects the adhesion of the pole piece.
  • the coating weight is 0.02-0.08 mg/ cm2
  • the first coating The peeling force with the second coating increases with the increase of the coating weight.
  • the coating weight is 0.08-0.15mg/ cm2
  • the peeling force between the first coating and the second coating decreases with the increase of the coating weight. Therefore, in some preferred embodiments of the present application, the coating weight X of the first coating layer satisfies: 0.02 mg/cm 2 ⁇ X ⁇ 0.15 mg/cm 2 .
  • the particle size of the inorganic particles is 50 nm ⁇ 1 ⁇ m.
  • the thickness of the first coating layer is 100 nm ⁇ 2 ⁇ m.
  • Example 3 It can be seen from Example 3, Examples 35-39 and Comparative Example 9 that the higher the coverage of the first coating, the stronger the pole piece adhesion.
  • the first The coverage of the coating on the surface of the current collector is 50% to 100%.
  • the adhesion force of the pole piece includes the peeling force between the first coating and the current collector and the peeling force between the first coating and the second coating.
  • the peeling force between the first coating and the second coating is much greater than the peeling force between the first coating and the second coating, so in this application, the peeling force between the first coating and the second coating is mainly used to reflect the adhesion force of the pole piece.

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Abstract

一种电化学装置，包括负极，所述负极包括集流体(1)、第一涂层(2)和第二涂层(3)，所述第二涂层(3)设置在所述集流体(1)的至少一个表面，所述第一涂层(2)设置在所述集流体(1)和所述第二涂层(3)之间，其中，所述第一涂层(2)包括无机粒子，所述第一涂层(2)与所述第二涂层(3)的剥离力F为：15N≤F≤30N。该电化学装置，通过在负极的集流体(1)与第二涂层(3)之间设置第一涂层(2)，该第一涂层(2)包含无机粒子，能够有效提升集流体(1)与第二涂层(3)之间的粘结力，降低第二涂层(3)的粘结剂含量，提高负极中负极活性物质的占比，从而提高锂离子电池的能量密度。

Description

一种电化学装置和电子设备 技术领域
本申请涉及电化学技术领域，具体涉及一种电化学装置和电子设备。
背景技术
在锂离子电池的制造和使用的过程中，负极活性材料容易从电极表面脱落，例如冷压过后容易造成脱碳，使电池容量下降；在电池使用过程中，由于负极材料体积会发生变化，也使得负极材料可能从极片表面脱落，从而产生安全隐患。
现有技术中多采用在集流体表面涂覆一层导电层，来缓解极片脱碳，但是现有的导电层往往厚度较大，造成能量密度损失，同时现有的导电层中，负极石墨与导电层有效粘接点位数量有限，电池长循环后依旧会出现脱碳现象。因此，亟需寻找一种新的提高极片粘性，减少负极活性材料脱落的途径。
发明内容
本申请的目的是提供一种电化学装置，通过在其负极的活性材料层和集流体之间设置合适的涂层，提高负极极片中负极活性物质与极片的粘结力。
本申请第一方面提供了一种电化学装置，包括负极，所述负极包括集流体、第一涂层和第二涂层，所述第二涂层设置在所述集流体的至少一个表面，所述第一涂层设置在所述集流体和所述第二涂层之间，其中，所述第一涂层包括无机粒子，所述第一涂层与所述第二涂层的剥离力F为：15N≤F≤30N。
在本申请第一方面的一些实施方式中，所述无机粒子的粒径Dv50满足50nm≤Dv50≤1μm。
在本申请第一方面的一些实施方式中，所述无机粒子的莫氏硬度为2.5至7.5。
在本申请第一方面的一些实施方式中，所述无机粒子包括勃姆石、铝粉、石英砂、磷灰石、纳米陶瓷或锆石中的至少一种。
在本申请第一方面的一些实施方式中，所述第一涂层还包括导电剂、粘结剂和分散剂，基于所述第一涂层的总质量，所述无机粒子、所述粘结剂、所述导电剂和所述分散剂的质量百分比为(2％～10％):(30％～60％): (30％～60％):(2％～5％)。
在本申请第一方面的一些实施方式中，所述粘结剂包括丁苯橡胶、聚丙烯酸、聚乙烯醇、聚乙二醇、聚丙烯酸酯、聚丙烯腈、聚偏氟乙烯、聚氯乙烯、甲醛树脂、环糊精或氰基丙烯酸酯中的至少一种。
在本申请第一方面的一些实施方式中，所述分散剂包括羟甲基纤维素钠、羟甲基纤维素锂、海藻酸钠、丙二醇藻蛋白酸酯、甲基纤维素、淀粉磷酸钠、羧甲基纤维素钠、藻蛋白酸钠、酪蛋白、聚丙烯酸钠、聚氧乙烯或聚乙烯吡咯烷酮中的至少一种。
在本申请第一方面的一些实施方式中，所述导电剂包括零维导电剂或一维导电剂中的至少一种。
在本申请第一方面的一些实施方式中，满足以下特征中的至少一者：
所述零维导电剂包括导电碳黑、乙炔黑或科琴黑中的至少一种，所述零维导电剂的Dv50为50nm至1μm；
所述一维导电剂包括导电碳管或导电碳棒中的至少一种，所述一维导电剂的平均直径为50nm至1μm。
在本申请第一方面的一些实施方式中，所述第一涂层的厚度L满足：100nm≤L≤2μm。
在本申请第一方面的一些实施方式中，所述第一涂层的涂覆重量X满足：0.02mg/cm 2≤X≤0.15mg/cm 2。
在本申请第一方面的一些实施方式中，所述第一涂层的覆盖率为50％至100％。
在本申请第一方面的一些实施方式中，所述第一涂层与所述集流体之间的剥离力为10N/m至300N/m。
在本申请第一方面的一些实施方式中，所述负极的电阻为1mΩ至100mΩ。
本申请第二方面提供了一种电子装置，包含本申请第一方面所提供的电化学装置。
本申请的电化学装置，通过在负极的集流体与第二涂层之间设置第一涂层，该第一涂层包含无机粒子，无机粒子被粘结剂包裹形成强度更高的粘接单元，一方面，粘结单元的形成使得第一涂层的粘结强度和粘结位点增加， 从而有效提升集流体与第二涂层之间的粘结力；另一方面强度更高的粘结单元可以使得第一涂层内聚力增加，该内聚力能抵消部分集流体的拉伸应力，从而增加集流体的强度，使得集流体在加工过程不易断裂。更进一步地，由于第一涂层增加了第二涂层与集流体之间的粘结力，因而可以减少第二涂层中粘结剂的含量，提高负极中负极活性物质的占比，从而提高锂离子电池的能量密度。
附图说明
为了更清楚地说明本发明实施例和现有技术的技术方案，下面对实施例和现有技术中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，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，还可以根据这些附图获得其他的附图。
图1为负极极片的结构示意图。
具体实施方式
为使本发明的目的、技术方案、及优点更加清楚明白，以下参照附图并举实施例，对本发明进一步详细说明。显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本申请第一方面提供了一种电化学装置，如图1所示，包括负极，所述负极包括集流体1、第一涂层2和第二涂层3，所述第二涂层3设置在所述集流体1的至少一个表面，所述第一涂层2设置在所述集流体1和所述第二涂层3之间，其中，所述第一涂层2包括无机粒子，所述第一涂层2与所述第二涂层3的剥离力F为：15N≤F≤30N。
本申请中，所述第二涂层3可以为负极活性材料层，发明人在研究中发现，当在第一涂层2中添加无机粒子后，能够明显增加第一涂层2与第二涂层3之间的剥离力，不限于任何理论，发明人认为这是因为无机粒子被粘结剂包裹形成强度更高的粘接单元，增加了第二涂层3中活性物质与第一涂层2之间的粘结强度和粘结位点。
本申请的负极极片第一涂层与负极活性材料层的剥离力能够达到 15N～30N，其中，现有技术中负极活性材料层与集流体或粘结涂层的剥离力很难达到10N以上，本申请的负极极片，负极活性材料层与极片的剥离力明显高于现有的负极极片。
本领域技术人员应当理解，本申请的集流体可以在其一个表面具有第一涂层和第二涂层，也可以在其两个表面均具有第一涂层和第二涂层，本领域技术人员根据实际需要进行选择即可。
在本申请第一方面的一些实施方式中，所述无机粒子的粒径Dv50满足50nm≤Dv50≤1μm。发明人在研究中发现，无机粒子的平均粒径Dv50大于50nm，能够避免无机粒子出现团聚；无机粒子的平均粒径Dv50大于1μm，会使第一涂层表面凹凸不平而影响锂离子电池的性能发挥。通过将无机粒子的平均粒径Dv50控制在上述范围内，一方面能够确保第一涂层厚度不会增加负极的厚度，避免锂离子电池的体积能量密度受到损失，另一方面又能够确保第一涂层表面的平整性，避免影响锂离子电池的性能发挥。
在本申请第一方面的一些实施方式中，所述无机粒子的莫氏硬度为2.5-7.5。发明人在研究中发现，无机粒子硬度过小，冷压过程容易变形，造成第一涂层内部结构稳定性变差，使得无机粒子和粘结剂形成的粘结单元的强度受影响；无机粒子硬度过大，对涂覆设备磨损较大。在本申请中，对无机粒子的种类没有特别限制，只要满足莫氏硬度在2.5至7.5的范围内，能实现本申请目的即可。例如，所述无机粒子可以包括勃姆石、铝粉、石英砂、磷灰石、纳米陶瓷或锆石中的至少一种，其中，锆石的莫氏硬度约为7.5，石英砂的莫氏硬度约为7，纳米陶瓷的莫氏硬度约为6，勃姆石的莫氏硬度约为3，铝粉莫氏硬度为2.75，磷灰石莫氏硬度为5。发明人发现，采用本申请的无机粒子，其与有机物相容性高，易分散，所以更适合做第一涂层2的添加剂。
在本申请第一方面的一些实施方式中，所述第一涂层还包括导电剂、粘结剂和分散剂，基于所述第一涂层的总质量，所述无机粒子、所述粘结剂、所述导电剂和所述分散剂的质量百分比为(2％～10％):(30％～60％):(30％～60％):(2％～5％)。发明人在研究中发现，当无机粒子质量占第一涂层总质量的比例小于2％时，体现不出无机粒子的高强度作用，当无机粒子质量占第一涂层总质量的比例大于10％时，容易出现无机粒子难以分散、颗粒团聚 的现象，还会增加极片的内阻；通过将分散剂质量控制在第一涂层总质量的2％至5％，能够使第一涂层的内部结构均匀、稳定，有效防止无机粒子的团聚；当粘结剂的质量占第一涂层总质量的比例小于30％时，粘结作用不明显；当粘结剂的质量占第一涂层总质量的比例大于60％时，粘结剂含量过多，易造成无机粒子团聚；通过将导电剂质量控制在第一涂层总质量的30％至60％，使负极的导电性能得以提升。
在本申请中，对粘结剂的种类没有特别限制，只要能够实现本申请目的即可。例如，粘结剂可以包含丁苯橡胶、聚丙烯酸、聚乙烯醇、聚乙二醇、聚偏氟乙烯、聚氯乙烯、甲醛树脂、环糊精或氰基丙烯酸酯等中的至少一种。粘结剂的加入能够提高第一涂层的粘性，从而分别提高第一涂层与负极集流体间、第一涂层与第二涂层间的粘结力，也能够减少第二涂层中粘结剂的含量。
在本申请中，对分散剂的种类没有特别限制，只要能够实现本申请目的即可。例如，分散剂可以包含羟甲基纤维素钠、羟甲基纤维素锂、海藻酸钠、丙二醇藻蛋白酸酯、甲基纤维素、淀粉磷酸钠、羧甲基纤维素钠、藻蛋白酸钠、酪蛋白、聚丙烯酸钠、聚氧乙烯或聚乙烯吡咯烷酮等中的至少一种。分散剂的加入能够提高第一涂层内部结构的均匀、稳定性，防止无机粒子的团聚。
在本申请第一方面的一些实施方式中，导电剂可以包含零维导电剂和一维导电剂中的至少一种。
在本申请中，对零维导电剂和一维导电剂的种类没有特别限制，能够实现本申请目的即可，例如，零维导电剂可以包含导电碳黑、乙炔黑、超导碳黑、颗粒石墨或科琴黑等中的至少一种，零维导电剂的平均粒径Dv50为50nm至1μm；一维导电剂可以包含导电碳管或导电碳棒等中的至少一种，一维导电剂的平均直径为50nm至1μm。通过导电剂的加入，能够提升负极的导电性能。通过将导电剂的平均粒径或平均直径控制在上述范围内，能够有效控制第一涂层的厚度，避免锂离子电池体积能量密度的损失。
在本申请第一方面的一些实施方式中，所述第一涂层2的厚度L满足：100nm≤L≤2μm；选地，200nm≤L≤1μm。通过将第一涂层的厚度控制在 上述范围内，能够有效控制负极厚度的增加，从而改善锂离子电池的能量密度。
在本申请第一方面的一些实施方式中，所述第一涂层2的涂覆重量X满足：0.02mg/cm 2≤X≤0.15mg/cm 2。通过将第一涂层的涂覆重量控制在上述范围内，能够有效控制第一涂层的厚度和涂覆均匀性，能够使第一涂层的性能得到有效发挥，从而提升锂离子电池的能量密度。
在本申请第一方面的一些实施方式中，所述第一涂层在所述集流体上的的覆盖率为50％～100％。通过控制第一涂层的覆盖率在50％以上，使第一涂层有效发挥其作用，使锂离子电池的性能得以改善。
在本申请第一方面的一些实施方式中，所述第一涂层2与所述集流体1之间的剥离力为10N/m至300N/m。
在本申请第一方面的一些实施方式中，所述负极极片的电阻为1mΩ至100mΩ。发明人在研究中发现，负极极片电阻在上述范围内，能够增大锂离子电池的极化、减小电能的释放，从而提高锂离子电池的安全性。
本申请的负极中，集流体没有特别限制，可以使用本领域公知的负极集流体，例如铜箔、铝箔、铝合金箔以及复合集电体等。负极活性物质层包括负极活性物质，负极活性物质没有特别限制，可以使用本领域公知的负极活性物质。例如，可以包括人造石墨、天然石墨、中间相碳微球、硅、硅碳、硅氧化合物、软碳、硬碳、钛酸锂或钛酸铌等中的至少一种。在本申请中，负极集流体和负极活性物质层的厚度没有特别限制，只要能够实现本申请目的即可。例如，负极集流体的厚度为6μm至10μm，负极活性物质层的厚度为30μm至120μm。
本申请中的正极没有特别限制，只要能够实现本申请目的即可。例如，正极通常包含正极集流体和正极活性物质层。其中，正极集流体没有特别限制，可以为本领域公知的正极集流体，例如铜箔、铝箔、铝合金箔以及复合集流体等。正极活性物质层包括正极活性物质，正极活性物质没有特别限制，可以为本领域公知的正极活性物质，例如，包括镍钴锰酸锂(811、622、523、111)、镍钴铝酸锂、磷酸铁锂、富锂锰基材料、钴酸锂、锰酸锂、磷酸锰铁锂或钛酸锂中的至少一种。在本申请中，正极集流体和正极活性物质层的厚 度没有特别限制，只要能够实现本申请目的即可。例如，正极集流体的厚度为8μm至12μm，正极活性物质层的厚度为30μm至120μm。
任选地，正极还可以包含导电层，该导电层位于正极集流体和正极活性物质层之间。导电层的组成没有特别限制，可以是本领域常用的导电层。该导电层包括导电剂和粘结剂。
本申请的锂离子电池还包括隔离膜，用以分隔正极和负极，防止锂离子电池内部短路，允许电解质离子自由通过，完成电化学充放电过程的作用。在本申请中，隔离膜没有特别限制，只要能够实现本申请目的即可。
例如，聚乙烯(PE)、聚丙烯(PP)为主的聚烯烃(PO)类隔离膜，聚酯膜(例如聚对苯二甲酸二乙酯(PET)膜)、纤维素膜、聚酰亚胺膜(PI)、聚酰胺膜(PA)，氨纶或芳纶膜、织造膜、非织造膜(无纺布)、微孔膜、复合膜、隔膜纸、碾压膜、纺丝膜等中的至少一种。
例如，隔离膜可以包括基材层和表面处理层。基材层可以为具有多孔结构的无纺布、膜或复合膜，基材层的材料可以包括聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯和聚酰亚胺等中的至少一种。任选地，可以使用聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯无纺布、聚乙烯无纺布或聚丙烯-聚乙烯-聚丙烯多孔复合膜。任选地，基材层的至少一个表面上设置有表面处理层，表面处理层可以是聚合物层或无机物层，也可以是混合聚合物与无机物所形成的层。
例如，无机物层包括无机颗粒和粘结剂，该无机颗粒没有特别限制，例如可以选自氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙和硫酸钡等中的至少一种。粘结剂没有特别限制，例如可以选自聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚甲基丙烯酸甲酯、聚四氟乙烯和聚六氟丙烯中的一种或几种的组合。聚合物层中包含聚合物，聚合物的材料包括聚酰胺、聚丙烯腈、丙烯酸酯聚合物、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯醚、聚偏氟乙烯或聚(偏氟乙烯-六氟丙烯)等中的至少一种。
本申请的锂离子电池还包括电解质，电解质可以是凝胶电解质、固态电解质和电解液中的一种或多种，电解液包括锂盐和非水溶剂。
在本申请第一方面的一些实施方式中，锂盐选自LiPF 6、LiBF 4、LiAsF 6、LiClO 4、LiB(C 6H 5) 4、LiCH 3SO 3、LiCF 3SO 3、LiN(SO 2CF 3) 2、LiC(SO 2CF 3) 3、LiSiF 6、LiBOB和二氟硼酸锂中的一种或多种。举例来说，锂盐可以选用LiPF 6，因为它可以给出高的离子导电率并改善循环特性。
非水溶剂可为碳酸酯化合物、羧酸酯化合物、醚化合物、其它有机溶剂或它们的组合。
上述碳酸酯化合物可为链状碳酸酯化合物、环状碳酸酯化合物、氟代碳酸酯化合物或其组合。
上述链状碳酸酯化合物的实例为碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸甲乙酯(MEC)及其组合。环状碳酸酯化合物的实例为碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸亚丁酯(BC)、碳酸乙烯基亚乙酯(VEC)及其组合。氟代碳酸酯化合物的实例为碳酸氟代亚乙酯(FEC)、碳酸1,2-二氟亚乙酯、碳酸1,1-二氟亚乙酯、碳酸1,1,2-三氟亚乙酯、碳酸1,1,2,2-四氟亚乙酯、碳酸1-氟-2-甲基亚乙酯、碳酸1-氟-1-甲基亚乙酯、碳酸1,2-二氟-1-甲基亚乙酯、碳酸1,1,2-三氟-2-甲基亚乙酯、碳酸三氟甲基亚乙酯及其组合。
上述羧酸酯化合物的实例为甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸正丙酯、乙酸叔丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、γ-丁内酯、癸内酯、戊内酯、甲瓦龙酸内酯、己内酯及其组合。
上述醚化合物的实例为二丁醚、四甘醇二甲醚、二甘醇二甲醚、1,2-二甲氧基乙烷、1,2-二乙氧基乙烷、乙氧基甲氧基乙烷、2-甲基四氢呋喃、四氢呋喃及其组合。
上述其它有机溶剂的实例为二甲亚砜、1,2-二氧戊环、环丁砜、甲基环丁砜、1,3-二甲基-2-咪唑烷酮、N-甲基-2-吡咯烷酮、甲酰胺、二甲基甲酰胺、乙腈、磷酸三甲酯、磷酸三乙酯、磷酸三辛酯、和磷酸酯及其组合。
电化学装置的制备过程为本领域技术人员所熟知的，本申请没有特别的 限制。例如电化学装置可以通过以下过程制造：将正极和负极经由隔离膜重叠，并根据需要将其卷绕、折叠等操作后放入壳体内，将电解液注入壳体并封口。此外，也可以根据需要将防过电流元件、导板等置于壳体中，从而防止电化学装置内部的压力上升、过充放电。
本申请第二方面提供了一种电子装置，其包含本申请第一方面所提供的电化学装置。
本申请的电子装置没有特别限定，其可以是用于现有技术中已知的任何电子装置。在一些实施例中，电子装置可以包括但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
以下，基于实施例对本申请进行具体地说明，但本申请并不限于这些实施例。
测试方法和设备：
无机粒子平均粒径Dv50的测试方法：
使用马尔文激光粒度仪MS3000测试无机粒子平均粒径Dv50。
Dv50是指，无机粒子在体积基准的粒度分布中从小粒径侧起达到体积累积50％的粒径，即，小于此粒径的无机粒子的体积占无机粒子总体积的50％。
第一涂层和第二涂层的厚度测试：
1)将涂有第一涂层和第二涂层的负极极片从成品锂离子电池中拆出；
2)使用等离子体切割技术，沿负极极片厚度方向切割1)中所得负极极片，得到第一涂层和第二涂层的横截面；
3)在SEM(电子显微镜)下，观察2)中所得第一涂层和第二涂层的横截面(要求所观察的横截面长度需不少于2cm)，在SEM下分别测试第一涂层、 第二涂层的厚度，每层需测试不少于15个不同的位置，记各层所有测试位置的厚度均值为对应层的厚度值。
第一涂层覆盖率测试方法：
(1)将极片的实际面积计为S1；
(2)将上述极片放入去离子水中浸泡2h后，将极片上层的石墨层擦去，露出的底涂层面积计为S2；
(3)通过以下表达式计算涂层的覆盖率B:B＝S2/S1×100％
第一涂层与第二涂层粘接力测试
1)取实施例1-19以及对比例1、2制备的负极极片，用刀片截取宽30mm，长度为100-160mm的试样；
2)将专用双面胶贴于钢板上，胶带宽度20mm，长度90-150mm；
3)将第(1)步截取的极片试样贴在双面胶上，测试面朝下；
4)将宽度与极片等宽，长度大于试样长度80-200mm的纸带插入极片下方，并且用皱纹胶固定；
5)打开三思拉力机电源，指示灯亮，调整限位块到合适位置。
6)点击测试，设备开启测试模式，待结束后读取数据即可。
第一涂层与集流体粘结力测试：
1)取实施例1-19以及对比例1、2在制备负极极片过程中，在集流体上形成第一涂层，还未涂覆负极活性材料层的负极极片，用刀片截取宽30mm，长度为100-160mm的试样；
2)将专用双面胶贴于钢板上，胶带宽度20mm，长度90-150mm；
3)将第(1)步截取的极片试样贴在双面胶上，测试面朝下；
4)将宽度与极片等宽，长度大于试样长度80-200mm的纸带插入极片下方，并且用皱纹胶固定；
5)打开三思拉力机电源，指示灯亮，调整限位块到合适位置。
6)点击测试，设备开启测试模式，待结束后读取数据即可。
循环性能测试：
测试温度为25/45℃，以0.7C恒流充电到4.4V，恒压充电到0.025C，静置5分钟后以0.5C放电到3.0V。以此步得到的容量为初始容量，进行0.7C充电/0.5C放电进行循环测试，以每一步的容量与初始容量做比值，得到容量衰减曲线。以25℃循环截至到容量保持率为90％的圈数记为锂离子电池的室温循环性能，以45℃循环截至到80％的圈数记为锂离子电池的高温循环性能，通过比较上述两种情况下的循环圈数而得到材料的循环性能。
放电倍率测试：
在25℃下，以0.2C放电到3.0V，静置5min，以0.5C充电到4.45V，恒压充电到0.05C后静置5分钟，调整放电倍率，分别以0.2C、0.5C、1C、1.5C、2.0C进行放电测试，分别得到放电容量，以每个倍率下得到的容量与0.2C得到的容量对比，通过比较2C与0.2C下的比值比较倍率性能。
实施例1
<第一涂层浆料的制备>
将碳纳米管和羟甲基纤维素钠(CMC)放置搅拌罐中分散均匀，加入一定量的去离子水加速分散，待羟甲基纤维素钠完全溶解无胶块呈现后，将一定量的石英砂倒入其中，三者再次混合分散，最后将粘结剂丁苯橡胶加入，再次分散，即得。其中碳纳米管、羟甲基纤维素钠、石英砂和丁苯橡胶的质量比为37:4:4:55，石英砂Dv50为200nm。
<含有第一涂层的负极极片的制备>
将制得的第一涂层浆料涂覆在负极集流体铜箔表面，得到厚度为380nm的第一涂层，第一涂层覆盖率90％，第一涂层的涂覆重量为0.08mg/cm 2；
将负极活性物质石墨、苯乙烯-丁二烯聚合物和羧甲基纤维素钠按照重量比97.5:1.3:1.2进行混合，加入去离子水作为溶剂，调配成为固含量为70％的浆料，并搅拌均匀。将浆料均匀涂覆在第一涂层上，110℃条件下烘干，冷压后得到负极活性物质层厚度为150μm的单面涂覆第一涂层和负极活性物质层的负极极片。
以上步骤完成后，采用同样的方法在该负极极片背面也完成这些步骤， 即得到双面涂布完成的负极极片。涂布完成后，将负极极片裁切成规格为76mm×851mm的片材并焊接极耳待用。
<正极极片的制备>
将正极活性材料钴酸锂(LiCoO 2)、导电炭黑(Super P)、聚偏二氟乙烯(PVDF)按照重量比97.5:1.0:1.5进行混合，加入N-甲基吡咯烷酮(NMP)作为溶剂，调配成为固含量为75％的浆料，并搅拌均匀。将浆料均匀涂覆在厚度为10μm的正极集流体铝箔的一个表面上，90℃条件下烘干，得到涂层厚度为110μm的正极极片。以上步骤完成后，即完成正极极片的单面涂布。之后，在该正极极片的另一个表面上重复以上步骤，即得到双面涂布正极活性材料的正极极片。涂布完成后，将极片裁切成38mm×58mm的规格待用。
<电解液的制备>
在干燥氩气气氛中，将有机溶剂碳酸乙烯酯、碳酸甲乙酯和碳酸二乙酯以质量比EC:EMC:DEC＝30:50:20混合得到有机溶液，然后向有机溶剂中加入锂盐六氟磷酸锂溶解并混合均匀，得到锂盐的浓度为1.15mol/L的电解液。
<隔离膜的制备>
将氧化铝与聚偏氟乙烯依照质量比90:10混合并将其溶入到去离子水中以形成固含量为50％的陶瓷浆料。随后采用微凹涂布法将陶瓷浆料均匀涂布到多孔基材(聚乙烯，厚度7μm，平均孔径为0.073μm，孔隙率为26％)的其中一面上，经过干燥处理以获得陶瓷涂层与多孔基材的双层结构，陶瓷涂层的厚度为50μm。
将聚偏二氟乙烯(PVDF)与聚丙烯酸酯依照质量比96:4混合并将其溶入到去离子水中以形成固含量为50％的聚合物浆料。随后采用微凹涂布法将聚合物浆料均匀涂布到上述陶瓷涂层与多孔基材双层结构的两个表面上，经过干燥处理以获得隔离膜，其中聚合物浆料形成的单层涂层厚度为2μm。
<锂离子电池的制备>
将上述制备的正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正负极极片中间起到隔离的作用，并卷绕得到电极组件。将电极组件装入铝 塑膜包装袋中，并在80℃下脱去水分，注入配好的电解液，经过真空封装、静置、化成、整形等工序得到锂离子电池。
实施例2
除了将石英砂替换为锆石粉，其余与实施例1相同。
实施例3
除了将石英砂替换为勃姆石，其余与实施例1相同。
实施例4
除了调整碳纳米管、羟甲基纤维素钠、勃姆石和丁苯橡胶的质量比为37:4:3:56，其余与实施例3相同。
实施例5
除了调整碳纳米管、羟甲基纤维素钠、勃姆石和丁苯橡胶的质量比为37:4:5:54，其余与实施例3相同。
实施例6
除了调整碳纳米管、羟甲基纤维素钠、勃姆石和丁苯橡胶的质量比为37:4:10:49，其余与实施例3相同。
实施例7
除了将粘结剂丁苯橡胶替换为质量比1:1的甲醛树脂和环糊精的混合物，并且调整碳纳米管、羟甲基纤维素钠、勃姆石和粘结剂的质量比为57:4:4:35，其余与实施例3相同。
实施例8
将粘结剂丁苯橡胶替换为质量比为4:6的聚乙烯醇与聚丙烯酸的混合物；将碳纳米管替换为导电碳棒；将分散剂CMC替换为聚乙烯吡咯烷酮(PVP)；并且调整导电碳棒、PVP、勃姆石和粘结剂的质量比为43:4:4:49，其余与实施例3相同。
实施例9
将粘结剂丁苯橡胶替换为聚丙烯腈，将碳纳米管替换为乙炔黑；将分散 剂CMC替换为酪蛋白；并且调整乙炔黑、酪蛋白、勃姆石和聚丙烯腈的质量比为39：3：4：54，其余与实施例3相同。
实施例10
将粘结剂丁苯橡胶替换为聚丙烯酸，将分散剂CMC替换为海藻酸钠(SA)；并且调整碳纳米管、海藻酸钠、勃姆石和聚丙烯酸的质量比为38：2：4：56，其余与实施例3相同。
实施例11
除了将粘结剂丁苯橡胶替换为质量比4:5:1的聚丙烯腈、聚丙烯酸和聚丙烯酸酯的混合物，并且调整碳纳米管、羟甲基纤维素钠、勃姆石和粘结剂的质量比为32:5:4:59，其余与实施例3相同。
实施例12
除了将碳纳米管替换为导电炭黑，并将涂覆重量调整为0.02mg/cm 2，其余与实施例3相同。
实施例13-17
除了将涂覆重量分别调整为0.05mg/cm 2、0.08mg/cm 2、0.1mg/cm 2、0.13mg/cm 2、0.15mg/cm 2，其余与实施例12相同。
实施例18
除了调整勃姆石的Dv50为50nm，并调整第一涂层的厚度为1000nm，其余与实施例3相同。
实施例19-26
除了调整勃姆石的粒径Dv50为100nm、150nm、200nm、300nm、350nm、400nm、800nm、1000nm，其余与实施例18相同。
实施例27
除了调整勃姆石的Dv50为100nm，并调整第一涂层的厚度为100nm，其余与实施例3相同。
实施例28-34
除了调整第一涂层的厚度为220nm、300nm、380nm、580nm、650nm、 800nm、1700nm，其余与实施例27相同。
实施例35-39
除了分别调整第一涂层覆盖率为100％、80％、70％、60％、50％，其余与实施例3相同。
对比例1
除了调整碳纳米管、羟甲基纤维素钠、石英砂和丁苯橡胶的质量比为41:4:0:55，其余与实施例1相同。
对比例2
除了将勃姆石替换为氧化铝，其余与实施例3相同。
对比例3、4
除了将涂覆重量分别调整为0.01mg/cm 2、0.16mg/cm 2，其余与实施例12相同。
对比例5、6
除了调整勃姆石的粒径Dv50为45nm和1050nm，其余与实施例18相同。
对比例7、8
除了调整第一涂层的厚度为2100nm和50nm，其余与实施例27相同。
对比例9
除了调整第一涂层覆盖率为45％，其余与实施例3相同。
各实施例和对比例的参数及测试结果见表1-表5。
Figure PCTCN2020135869-appb-000001
Figure PCTCN2020135869-appb-000002
Figure PCTCN2020135869-appb-000003
Figure PCTCN2020135869-appb-000004
本申请的电化学装置，其负极极片的第一涂层与第二涂层之间的剥离力显著提升，均能够达到15N以上，由于极片粘结力提高，电池的倍率性能和循环性能也相应提高。
从实施例1-3及对比例1和2中可以看出，第一涂层中加入无机粒子对提高极片的剥离力有着巨大影响，无机粒子的种类也影响极片的粘度，发明人在研究中意外的发现，当无机粒子的莫氏硬度在2.5至7.5时，其对提高极片粘结力的作用更加明显。示例性地，当加入氧化铝时(莫氏硬度为9)，第一涂层与第二涂层的剥离力仅从5N提高到7N，而采用勃姆石时，则提高到25N。
从实施例4-6中可以看出，无机粒子的质量含量在2％至10％时，极片具有更高的粘结力，第一涂层与第二涂层的剥离力能够达到20N以上。在本申请的一些优选地实施方式中，无机粒子的含量为2％至5％。
从实施例7-11中可以看出，当粘结剂的质量含量在30％～60％，导电剂含量在60％～30％，分散剂的质量含量在2-5％的范围内，第一涂层与第二涂层之间的剥离力均大于15N，第一涂层与第二涂层之间的剥离力随粘结剂含量增加而增大；随着粘结剂含量升高，导电剂含量逐渐下降，从实施例11中可以看出，随着导电剂含量的下降，虽然极片粘结力提高了，但是电池的倍率放电性能和循环性能却下降了，因此，在本申请的一些实施方式中，粘结剂的质量含量在30％～60％，导电剂含量在30％～60％。
另外，从实施例7-11中还可以看出，采用本申请的不同类型的粘结剂、分散剂和导电剂，均能够使第一涂层与第二涂层之间具有较高的剥离力。
从实施例12-17以及对比例3、4中可以看出，第一涂层的涂覆重量影响极片的粘结力，涂覆重量在0.02-0.08mg/cm 2时，第一涂层与第二涂层的剥离力随涂覆重量增加而升高，涂覆重量在0.08-0.15mg/cm 2时，第一涂层与第二涂层的剥离力随涂覆重量增加而减小，因此在本申请的一些优选的实施方式中，第一涂层的涂覆重量X满足：0.02mg/cm 2≤X≤0.15mg/cm 2。
从实施例18-26以及对比例5、6中可以看出，无机粒子的粒径Dv50在200nm以下时，第一涂层与第二涂层之间的剥离力随粒径增大逐渐增大，当粒径大于200nm时，第一涂层与第二涂层之间的剥离力随粒径增大逐渐减小，因此，在本申请一些优选地实施方式中，无机粒子的粒径为50nm～1μm。
从实施例27-34以及对比例7、8中可以看出，第一涂层厚度在380nm以下时，第一涂层与第二涂层之间的剥离力随涂层厚度增加逐渐增大，当第一涂层厚度大于380nm时，第一涂层与第二涂层之间的剥离力随涂层厚度增大逐渐减小，而且随着涂层厚度的增加，电池的能量密度也随之降低，因此，在本申请一些优选地实施方式中，第一涂层的厚度为100nm～2μm。
从实施例3、实施例35-39以及对比例9中可以看出，第一涂层的覆盖率越高，极片粘结力越强，在本申请的一些实施方式中，所述第一涂层在所述集流体表面的覆盖率为50％～100％。
此处需要说明的是，极片的粘结力包括第一涂层与集流体之间的剥离力以及第一涂层与第二涂层之间的剥离力，由于一涂层与集流体之间的剥离力远大于第一涂层与第二涂层之间的剥离力，因此本申请中主要以第一涂层与第二涂层之间的剥离力反映极片的粘结力。
以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明保护的范围之内。

Claims (15)

  1. 一种电化学装置，包括负极，所述负极包括集流体、第一涂层和第二涂层，所述第二涂层设置在所述集流体的至少一个表面，所述第一涂层设置在所述集流体和所述第二涂层之间，其中，所述第一涂层包括无机粒子，所述第一涂层与所述第二涂层的剥离力F为：15N≤F≤30N。
  2. 根据权利要求1所述的电化学装置，其中，所述无机粒子的粒径Dv50满足50nm≤Dv50≤1μm。
  3. 根据权利要求1所述的电化学装置，其中，所述无机粒子的莫氏硬度为2.5至7.5。
  4. 根据权利要求1-3中任一项所述的电化学装置，其中，所述无机粒子包括勃姆石、铝粉、石英砂、磷灰石、纳米陶瓷或锆石的至少一种。
  5. 根据权利要求1所述的电化学装置，其中，所述第一涂层还包括导电剂、粘结剂和分散剂，基于所述第一涂层的总质量，所述无机粒子、所述粘结剂、所述导电剂和所述分散剂的质量百分比为(2％～10％):(30％～60％):(30％～60％):(2％～5％)。
  6. 根据权利要求5所述的电化学装置，其中，所述粘结剂包括丁苯橡胶、聚丙烯酸、聚乙烯醇、聚乙二醇、聚丙烯酸酯、聚丙烯腈、聚偏氟乙烯、聚氯乙烯、甲醛树脂、环糊精或氰基丙烯酸酯中的至少一种。
  7. 根据权利要求5所述的电化学装置，其中，所述分散剂包括羟甲基纤维素钠、羟甲基纤维素锂、海藻酸钠、丙二醇藻蛋白酸酯、甲基纤维素、淀粉磷酸钠、羧甲基纤维素钠、藻蛋白酸钠、酪蛋白、聚丙烯酸钠、聚氧乙烯或聚乙烯吡咯烷酮中的至少一种。
  8. 根据权利要求5所述的电化学装置，其中，所述导电剂包括零维导电剂或一维导电剂中的至少一种。
  9. 根据权利要求8所述的电化学装置，其中，满足以下特征中的至少一者：
    所述零维导电剂包括导电碳黑、乙炔黑或科琴黑中的至少一种，所述零维导电剂的Dv50为50nm至1μm；
    所述一维导电剂包括导电碳管或导电碳棒中的至少一种，所述一维导电 剂的平均直径为50nm至1μm。
  10. 根据权利要求1所述的电化学装置，其中，所述第一涂层的厚度L满足：100nm≤L≤2μm。
  11. 根据权利要求1所述的电化学装置，其中，所述第一涂层的涂覆重量X满足：0.02mg/cm 2≤X≤0.15mg/cm 2。
  12. 根据权利要求1所述的电化学装置，其中，所述第一涂层的覆盖率为50％至100％。
  13. 根据权利要求1所述的电化学装置，其中，所述第一涂层与所述集流体之间的剥离力为10N/m至300N/m。
  14. 根据权利要求1所述的电化学装置，其中，所述负极的电阻为1mΩ至100mΩ。
  15. 一种电子装置，其包含权利要求1-14中任一项所述的电化学装置。
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