WO2023168584A1 - Appareil électrochimique et appareil électronique - Google Patents

Appareil électrochimique et appareil électronique Download PDF

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WO2023168584A1
WO2023168584A1 PCT/CN2022/079668 CN2022079668W WO2023168584A1 WO 2023168584 A1 WO2023168584 A1 WO 2023168584A1 CN 2022079668 W CN2022079668 W CN 2022079668W WO 2023168584 A1 WO2023168584 A1 WO 2023168584A1
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active material
material layer
electrode
conductive agent
negative
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PCT/CN2022/079668
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English (en)
Chinese (zh)
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刘明举
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宁德新能源科技有限公司
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Priority to PCT/CN2022/079668 priority Critical patent/WO2023168584A1/fr
Priority to CN202280005101.0A priority patent/CN115843395A/zh
Publication of WO2023168584A1 publication Critical patent/WO2023168584A1/fr

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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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • 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

  • Embodiments of the present disclosure relate to the field of electrochemical technology, and in particular to an electrochemical device and an electronic device.
  • Electrochemical devices such as lithium-ion batteries
  • deformation adaptability requirements are put forward for electrochemical devices, and electrochemical The device has good flexibility.
  • an electrochemical device and an electronic device are proposed.
  • an electrochemical device including an electrode, the electrode includes an active material layer, the bending radius of the electrode is 0.5 mm to 1.5 mm, and the fracture elongation of the electrode is 2% to 8%. This shows that the electrode has good flexibility and deformation adaptability and can meet the needs of flexible electrochemical devices.
  • the electrode is a positive electrode
  • the active material layer is a positive active material layer
  • the positive active material layer includes a positive active material
  • the positive active material includes lithium iron phosphate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, manganese At least one of lithium acid oxide, lithium cobalt oxide or lithium-rich materials.
  • the thickness of the positive active material layer ranges from 40 ⁇ m to 2500 ⁇ m to meet capacity and flexibility requirements.
  • the positive active material layer has a compacted density of 2.2g/cm 3 to 4.3g/cm 3 .
  • the porosity of the positive active material layer is 20% to 30%, thereby ensuring energy density and kinetic performance.
  • the electrode is a positive electrode
  • the active material layer is a positive active material layer
  • the thickness of the positive active material layer is 40 ⁇ m to 320 ⁇ m.
  • the positive active material layer has a compacted density of 2.2g/cm 3 to 4.23g/cm 3 .
  • the electrode is a negative electrode
  • the active material layer is a negative active material layer.
  • the negative active material layer includes a negative active material
  • the negative active material includes lithium titanate, silicon-based materials, silicon oxide, silicon, silicon carbon, and graphite. Or at least one of hard carbon.
  • the thickness of the negative active material layer is 30 ⁇ m to 3000 ⁇ m, thereby ensuring capacity and flexibility.
  • the negative active material layer has a compacted density of 0.6g/cm 3 to 1.85g/cm 3 .
  • the porosity of the negative active material layer is 30% to 40%, thereby ensuring energy density and kinetic performance.
  • the electrode is a negative electrode
  • the active material layer is a negative active material layer
  • the thickness of the negative active material layer is 50 ⁇ m to 400 ⁇ m.
  • the negative active material layer has a compacted density of 1.3 to 1.8 g/cm 3 .
  • the active material layer includes an active material and a conductive agent
  • the conductive agent includes a first conductive agent
  • the first conductive agent includes carbon nanotubes, thereby improving long-range conductivity and structural strength of the active material layer.
  • the conductive agent further includes a second conductive agent, and the second conductive agent includes at least one of conductive carbon black, graphene, conductive graphite, or carbon fiber, thereby improving short-range conductivity.
  • the mass percentage of the active material in the active material layer ranges from 50% to 99%, and the conductive agent accounts for 1% to 50% in mass of the active material layer; Based on the total mass of the conductive agent, the mass percentage of the second conductive agent in the conductive agent ranges from 1% to 50%.
  • every 2 to 1000 carbon nanotubes are arranged to form bundled carbon nanotube aggregates.
  • the carbon nanotube aggregates are entangled with the second conductive agent to form a three-dimensional network structure, and at least some of the particles of the active material are located in the three-dimensional network. within the lattice structure, thereby improving the overall structural strength of the active material layer and ensuring dynamic performance.
  • the diameter of the carbon nanotube ranges from 0.5 nm to 10 nm, and the length of the carbon nanotube ranges from 1 ⁇ m to 100 ⁇ m, thereby ensuring the structural strength of the three-dimensional network structure.
  • This application also proposes an electronic device, including any of the electrochemical devices proposed in this application.
  • the bending radius of the electrodes of the electrochemical device in this application is 0.5mm to 1.5mm, and the fracture elongation of the electrodes is 2% to 8%, which shows that the electrodes have good flexibility and deformation adaptability and can meet the requirements for flexible electronics. Chemical plant needs.
  • Figure 1 is a schematic diagram of electrodes in some embodiments of the present application.
  • Electrochemical devices such as lithium-ion batteries
  • Electrochemical devices are widely used in various fields. With the development of technology, requirements have been put forward for the deformation adaptability of electrochemical devices. Electrochemical devices with good flexibility are needed, which can be used after multiple deformations. Still maintaining structural and functional integrity, and requiring energy density to meet demand.
  • the key to flexible electrochemical devices lies in flexible electrodes. In related technologies, electrodes have poor flexibility and bendability, and the presence of binders and current collectors reduces energy density.
  • an electrochemical device including an electrode, the electrode includes an active material layer, the bending radius of the electrode is 0.5 mm to 1.5 mm, and the fracture elongation of the electrode is 2% to 8%.
  • the electrochemical device can be a lithium ion battery, and the electrode can be the positive electrode or the negative electrode of the electrochemical device.
  • the bending radius of the electrode is measured as follows: press the electrode on a certain axis rod radius. On the stainless steel shaft rod, bend around the rod and hold for 2 to 3 seconds after bending. Remove the sample and use a 4x magnifying glass to observe whether there are reticulation, cracks or peeling of the active material layer on the electrode surface. The minimum rod radius that can be bent on rods with different rod radii without causing damage to the electrode is used as the bending radius of the electrode to characterize the flexibility of the electrode.
  • the electrode may not have a current collector, which can increase the energy density, and because there is no current collector, the use of a binder is avoided.
  • the electrode may not have a binder, which can increase the energy density. , it can also improve the overall dynamic properties of the active material layer and improve the conductivity, which is beneficial to improving rate performance and cycle performance.
  • the electrode is a positive electrode
  • the active material layer is a positive active material layer
  • the positive active material layer includes a positive active material
  • the positive active material includes lithium iron phosphate, lithium nickel cobalt manganate, and nickel cobalt aluminum oxide. At least one of lithium, lithium manganate, lithium cobalt oxide or lithium-rich materials.
  • the positive active material in the positive active material layer affects the capacity of the electrochemical device.
  • the positive active material has a higher gram capacity, which is beneficial to ensuring the energy density of the electrochemical device.
  • the thickness of the positive active material layer is 40 ⁇ m to 2500 ⁇ m. In some embodiments, the thicker the cathode active material layer and the greater the mass of the cathode active material, the more conducive to increasing the capacity of the cathode and thereby increasing the overall capacity of the electrochemical device. However, when the cathode active material layer is too thick, The overall flexibility of the positive active material layer will be affected. When the thickness of the positive active material layer is within the above range, it can have better flexibility and capacity at the same time. In some embodiments, the thickness of the positive active material layer is 40 ⁇ m. to 320 ⁇ m, thereby further improving flexibility and capacity. In some embodiments, the thickness of the positive active material layer is 100 ⁇ m to 200 ⁇ m.
  • the compacted density of the positive active material layer is 2.2g/cm 3 to 4.3g/cm 3 .
  • the compacted density of the positive electrode active material layer is related to flexibility. Too high a compacted density will lead to large internal stress of the positive electrode active material layer, which is not conducive to the flexibility. Too low a compacted density will cause the positive electrode active material layer to be inactive. The energy density of the material layer is lower.
  • the compacted density of the positive active material layer is 2.2g/cm 3 to 4.23g/cm 3 , thereby further obtaining better flexibility and energy density.
  • the porosity of the positive active material layer is 20% to 30%. In some embodiments, the porosity of the positive active material layer has an impact on the infiltration of the electrolyte and ion transmission. When the porosity of the positive active material layer is too small, the contact between the positive active material layer and the electrolyte is affected, and the ion transmission channel is reduced. , affects the kinetic performance and is not conducive to the rate performance. When the porosity of the positive active material layer is too large, it will affect the energy density and have an impact on the cycle performance.
  • the electrode is a negative electrode
  • the active material layer is a negative active material layer.
  • the negative active material layer includes negative active materials, and the negative active materials include lithium titanate, silicon-based materials, silicon oxide, silicon, and silicon carbon. At least one of graphite or hard carbon.
  • the negative active material may be a mixture of the above active materials, and the particle sizes of different negative active materials may be different.
  • the thickness of the negative active material layer is 30 ⁇ m to 3000 ⁇ m.
  • the thickness of the negative active material layer will affect the flexibility and energy density of the negative electrode. When the thickness of the negative active material layer is too large, the flexibility may be reduced. When the thickness of the negative active material layer is too small, it will be detrimental to the energy density. Setting the thickness of the negative active material layer within the above range can maintain good flexibility while ensuring energy density. In some embodiments, the thickness of the negative active material layer is 50 ⁇ m to 400 ⁇ m, and in some embodiments, the thickness of the negative active material layer is 100 ⁇ m to 200 ⁇ m.
  • the compacted density of the negative active material layer is 0.6g/cm 3 to 1.85g/cm 3 .
  • the compaction density of the negative active material layer will also affect the flexibility and energy density of the negative electrode. When the compaction density is too high, it is not conducive to the flexibility and can easily cause the particles of the negative active material to break. When the compaction density is too small, the energy will be affected. density.
  • the compacted density of the negative active material layer is 1.3g/cm 3 to 1.8g/cm 3 , thereby ensuring both the flexibility and energy density of the negative electrode.
  • the porosity of the negative active material layer is 30% to 40%. In some embodiments, the porosity of the negative active material layer has an impact on the infiltration of the electrolyte and ion transport. When the pores of the negative active material layer If the rate is too small, it will affect the contact between the negative active material layer and the electrolyte, reduce the ion transmission channel, affect the dynamic performance, and is not conducive to the rate performance. When the porosity of the negative active material layer is too large, it will affect the energy density, and for Cycling performance will be affected.
  • the active material layer includes an active material 10 and a conductive agent 20
  • the conductive agent 20 includes a first conductive agent 201
  • the first conductive agent 201 includes carbon nanotubes.
  • carbon nanotubes can improve the long-range conductivity of the active material layer, stabilize the structure of the active material layer, and ensure flexibility.
  • the linear structure of carbon nanotubes can enable ions to be transported over longer distances and connect active materials at different locations. layer to prevent the active material from breaking during bending and improve the elongation at break.
  • the conductive agent 20 further includes a second conductive agent.
  • the second conductive agent includes at least one of conductive carbon black, graphene, conductive graphite, or carbon fiber.
  • the second conductive agent may include zero-dimensional conductive agent 202 and Two-dimensional conductive agent 203.
  • the active material layer may only include the active material 10 and the conductive agent 20.
  • the active material of the positive electrode is the positive active material
  • the active material of the negative electrode is the negative active material, because the active material layer only includes the active material 10 and the conductive agent 20. It does not contain a polymer binder, so it avoids the obstruction of electron and ion transmission by the polymer binder, reduces the proportion of inactive materials, and increases the energy density.
  • the addition of linear carbon nanotubes increases the electrode
  • the flexibility and long-range conductivity improve deformation adaptability and stabilize the structure of the active material layer.
  • the second conductive agent increases the short-range conductivity of the active material layer. Through the first conductive agent and the second conductive agent, While ensuring flexibility and structural stability, it also improves the long-range conductivity and short-range conductivity of the active material layer.
  • the mass percentage of the active material in the active material layer ranges from 50% to 99%, and the conductive agent accounts for 1% to 50% in mass of the active material layer; Based on the total mass of the conductive agent, the mass percentage of the second conductive agent in the conductive agent ranges from 1% to 50%.
  • every 2 to 1000 carbon nanotubes are arranged to form bundled carbon nanotube aggregates.
  • the carbon nanotube aggregates are entangled with the second conductive agent to form a three-dimensional network structure, and at least some of the particles of the active material are located in the three-dimensional network. within the grid structure.
  • the bundled carbon nanotube aggregates formed by carbon nanotubes can improve the overall structural strength of the carbon nanotubes, and the three-dimensional network structure formed by them provides sites for active materials, so that the active material layer passes through the three-dimensional network structure. It can be well gathered together to improve the overall structural strength of the active material layer and ensure flexibility, and the three-dimensional network structure can enable better conduction of ions in multiple directions.
  • the diameter of the carbon nanotube is 0.5 nm to 10 nm, the diameter is the diameter of the carbon nanotube, and the length of the carbon nanotube is 1 ⁇ m to 100 ⁇ m. If the length of the carbon nanotube is too small, it will It is not conducive to stabilizing the structure of the active material layer, and the length of the carbon nanotubes is too long and may easily break.
  • the electrochemical device provided has good flexibility and can be self-supporting without the need for a current collector, reducing the proportion of inactive substances such as binders, which not only ensures flexibility and improves deformation adaptability properties and can also increase energy density.
  • the electrochemical device includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode.
  • the release film includes at least one of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, or aramid.
  • polyethylene includes at least one selected from high-density polyethylene, low-density polyethylene, or ultra-high molecular weight polyethylene.
  • the thickness of the isolation film ranges from about 5 ⁇ m to 50 ⁇ m.
  • the surface of the isolation membrane may also include a porous layer.
  • the porous layer is disposed on at least one surface of the isolation membrane.
  • the porous layer includes inorganic particles and a binder.
  • the inorganic particles are selected from aluminum oxide (Al 2 O 3 ), Silicon oxide (SiO 2 ), magnesium oxide (MgO), titanium oxide (TiO 2 ), hafnium dioxide (HfO 2 ), tin oxide (SnO 2 ), ceria (CeO 2 ), nickel oxide (NiO), oxide Zinc (ZnO), calcium oxide (CaO), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 O 3 ), silicon carbide (SiC), boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide or sulfuric acid At least one of barium.
  • the pores of the isolation film have a diameter in the range of about 0.01 ⁇ m to 1 ⁇ m.
  • the binder of the porous layer is selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, sodium carboxymethylcellulose, poly At least one of vinylpyrrolidone, polyvinyl ether, polymethylmethacrylate, polytetrafluoroethylene or polyhexafluoropropylene.
  • the porous layer on the surface of the isolation membrane can improve the heat resistance, oxidation resistance and electrolyte wetting performance of the isolation membrane, and enhance the adhesion between the isolation membrane and the pole piece.
  • the electrochemical device may be of a rolled or stacked type.
  • the positive electrode and/or negative electrode of the electrochemical device may be a multi-layer structure formed by being rolled or stacked, or may be a single-layer structure in which a single-layer positive electrode, a separator, and a single-layer negative electrode are stacked.
  • the electrochemical device includes a lithium-ion battery, although the application is not limited thereto.
  • the electrochemical device may also include an electrolyte.
  • the electrolyte may be one or more of a gel electrolyte, a solid electrolyte, and an electrolyte solution, and the electrolyte solution 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 2 CF 3 ) 2 , LiC(SO 2 CF 3 ) 3 , one or more of LiSiF 6 , LiBOB or lithium difluoroborate.
  • LiPF 6 was chosen for the lithium salt because it has high ionic conductivity and improves cycling characteristics.
  • the non-aqueous solvent may be a carbonate compound, a carboxylate compound, an ether compound, other organic solvents, or a combination thereof.
  • the carbonate compound may be a chain carbonate compound, a cyclic carbonate compound, a fluorocarbonate compound, or a combination thereof.
  • chain carbonate compounds are diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl carbonate Ethyl ester (MEC) and its combinations.
  • chain carbonate compounds are diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl carbonate Ethyl ester (MEC) and its combinations.
  • Examples of the cyclic carbonate compound are ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylethylene carbonate (VEC) or combinations thereof.
  • fluorocarbonate compound are fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate.
  • carboxylate compounds are methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, ⁇ -butyrolactone, decanolactone, Valerolactone, mevalonolactone, caprolactone, methyl formate or combinations thereof.
  • ether compounds are dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxy ethane, 2-methyltetrahydrofuran, tetrahydrofuran or combinations thereof.
  • organic solvents examples include dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, methane Amides, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, and phosphate esters or combinations thereof.
  • the positive electrode, separator, and negative electrode are wound or stacked in order to form an electrode piece, and then put into, for example, an aluminum-plastic film for packaging, and the electrolyte is injected to form, Encapsulated to make a lithium-ion battery. Then, the prepared lithium-ion battery was tested for performance.
  • electrochemical devices eg, lithium-ion batteries
  • electrochemical devices eg, lithium-ion batteries
  • Other methods commonly used in the art can be used without departing from the content disclosed in this application.
  • This application proposes an electronic device, including an electrochemical device; the electrochemical device is any electrochemical device of this application.
  • the electronic device in the embodiment of the present application is not particularly limited and can be used in any electronic device known in the prior art.
  • electronic devices may include, but are not limited to, laptop computers, pen computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headsets, Video recorders, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, Drones, lighting equipment, toys, game consoles, clocks, power tools, flashes, cameras or large household batteries, etc.
  • a method for preparing an electrode is also proposed.
  • the electrode in the embodiment of the present application can be prepared by this preparation method.
  • the preparation method includes the following steps:
  • first conductive agent carbon nanotubes and dispersing agent to the dispersion medium, which can be nitrogen methyl pyrrolidone (NMP) or water, and form a uniform first conductive agent dispersion through ultrasonic, stirring, sand grinding, etc.; add the active
  • the substance, the second conductive agent and the pore-forming agent are added to the first conductive agent dispersion, stir evenly to form a slurry; apply the slurry on the surface of the substrate and dry it at 80°C to 120°C.
  • the electrodes will automatically peel off from the substrate to form a self-contained slurry. Supported electrodes.
  • the dispersing agent includes sodium dodecyl sulfate (SDS), sodium dodecyl sulfonate (SDBS), cetyltrimethylammonium bromide (C16TMAB), polyvinylpyrrolidone (PVP) ), one or more of sodium carboxymethylcellulose (CMC-Na), lithium carboxymethylcellulose (CMC-Li); in some embodiments, the pore-forming agent includes 0.2 mol/L to 12 mol/ L of oxalic acid solution, 0.2mol/L to 12mol/L ammonium carbonate solution, 0.2mol/L to 12mol/L ammonium bicarbonate solution, 0.2mol/L to 12mol/L azodicarbonamide solution, lithium carbonate , one or more of lithium hydroxide.
  • SDS sodium dodecyl sulfate
  • SDBS sodium dodecyl sulfonate
  • C16TMAB cetyltrimethylammonium bromide
  • PVP polyvinylpyr
  • the base is polyethylene terephthalate (PET) with a release film
  • the release film has a thickness of 0 ⁇ m to 25 ⁇ m.
  • the release film can be a silicone oil coating, a polyurethane coating, or an acrylic coating. A type of coating.
  • the active material layer of the electrode prepared in some embodiments of the present application only contains active materials and conductive agents, and does not contain polymer binders, which avoids the binder's hindrance to electron and ion transmission and reduces the proportion of inactive materials.
  • the energy density is increased.
  • the addition of pore-forming agent during the preparation process increases the porosity of the electrode, reduces the transmission distance of lithium ions, and improves the rate performance.
  • the addition of long-range linear conductive carbon materials increases the flexibility of the electrode and improves the rate performance. Deformation adaptability.
  • the first conductive agent carbon nanotubes and dispersant are added to the dispersion medium nitrogen methyl pyrrolidone (NMP), and a uniform first conductive agent dispersion is formed through ultrasonic, stirring, sand grinding and other methods; the positive electrode active material lithium cobalt oxide, Add the second conductive agent graphene and pore-forming agent to the first conductive agent dispersion, stir evenly to form a slurry; apply the slurry on the surface of the polyethylene terephthalate with the release film on the base, and bake at 90°C When dry, the positive active material layer is automatically peeled off from the matrix to form a positive electrode.
  • NMP nitrogen methyl pyrrolidone
  • Preparation of the negative electrode Mix the negative active material graphite, styrene acrylate and carboxymethyl cellulose lithium at a mass ratio of 98:1:1, use deionized water as the solvent to form a slurry for the negative active material layer, and use copper
  • the foil is used as the negative electrode current collector.
  • the slurry of the negative electrode active material layer is coated on the negative electrode current collector and dried at 90°C to obtain the negative electrode.
  • the isolation film is 8 ⁇ m thick polyethylene (PE).
  • Preparation of lithium-ion battery Stack the positive electrode, isolation film, and negative electrode in order so that the isolation film is between the positive electrode and the negative electrode for isolation, and wind it to obtain the electrode assembly.
  • the electrode assembly is placed in the outer packaging aluminum plastic film, and after the moisture is removed at 80°C, the above-mentioned electrolyte is injected and packaged. After formation, degassing, trimming and other processes, a lithium-ion battery is obtained.
  • Preparation of the positive electrode Mix the positive active materials lithium cobalt oxide, polyvinylidene fluoride (PVDF), conductive carbon black (Super P, SP) and carbon nanotubes (CNT) according to the mass ratio of 97.2:1.5:0.8:0.5 to N-methylpyrrolidone (NMP) is used as a solvent to form a slurry, and the mixture is stirred evenly to form a slurry for the positive electrode active material layer. The slurry is evenly coated on the positive electrode current collector aluminum foil and dried at 90°C to obtain a positive electrode.
  • PVDF polyvinylidene fluoride
  • Super P, SP conductive carbon black
  • CNT carbon nanotubes
  • Preparation of the negative electrode Add the first conductive agent carbon nanotubes and the dispersant lithium carboxymethylcellulose to the dispersion medium deionized water, and form a uniform first conductive agent dispersion through ultrasonic, stirring, sanding and other methods; add the negative electrode active Add the material graphite, the second conductive agent graphene and the pore-forming agent 1 mol/L oxalic acid solution to the first conductive agent dispersion, stir evenly to form a slurry; apply the slurry to the polyterephthalate with the release film on the base The surface of ethylene glycol formate is dried at 90°C, and the negative active material layer is automatically peeled off from the matrix to form the negative electrode.
  • Example 14 The remaining preparation steps of Example 14 are the same as those of Example 1.
  • Embodiment 15 to Embodiment 22 are parameter changes based on the steps of Embodiment 14. The specific parameters changed are as shown in the table below.
  • Preparation of the positive electrode Mix the positive active materials lithium cobalt oxide, polyvinylidene fluoride (PVDF), conductive carbon black (Super P, SP) and carbon nanotubes (CNT) according to the mass ratio of 97.2:1.5:0.8:0.5 to N-methylpyrrolidone (NMP) is used as a solvent to form a slurry, and the mixture is stirred evenly to form a slurry for the positive electrode active material layer. The slurry is evenly coated on the positive electrode current collector aluminum foil and dried at 90°C to obtain a positive electrode.
  • PVDF polyvinylidene fluoride
  • Super P, SP conductive carbon black
  • CNT carbon nanotubes
  • Preparation of the negative electrode Mix the negative active material graphite, the binder styrene-butadiene rubber and the dispersant lithium carboxymethylcellulose in a mass ratio of 95:3.5:1.5, and use deionized water as the solvent to form a slurry of the negative active material layer Material, copper foil is used as the negative electrode current collector, the slurry of the negative electrode active material layer is coated on the negative electrode current collector, and dried at 90°C to obtain the negative electrode.
  • Comparative Example 1 The remaining preparation steps of Comparative Example 1 are the same as those of Example 1. Comparative Examples 2 and 3 made parameter changes based on the steps of Comparative Example 1. The specific changed parameters are shown in the table below.
  • 3C discharge capacity retention rate (3C discharge capacity/discharge capacity at 0.2C) ⁇ 100%
  • Table 1 and Table 2 show the differences in preparation parameters and performance test results of Examples 1 to 5, and the remaining preparation parameters not shown are the same.
  • the positive electrode uses the electrode proposed in this application. It can be seen that the bending radius of the positive electrode is 0.5mm to 1.5mm, and the fracture elongation is 2% to 8%, which indicates that the positive electrode has good flexibility. , it can be seen that the DC resistance in Examples 1 to 5 is smaller, and the test results of rate performance and cycle performance are also better. This may be because there is no polymer binder in the positive electrode in Examples 1 to 5 of the present application, which avoids Effect of polymer binders on dynamic properties.
  • Example 6 The preparation parameters and performance test results of Examples 6 to 13 are shown in Table 3 and Table 4, and the remaining preparation parameters not shown are the same as Example 1.
  • the positive electrode of the electrochemical device uses the pole piece proposed in this application. From Examples 6 to 9, it can be seen that the type of the second conductive agent in the positive active material layer has an important impact on the performance of the electrochemical device. It can be seen that when the second conductive agent is carbon fiber, conductive carbon black, carbon nanotubes or conductive graphite, they all have better performance. Among them, when the second conductive agent is carbon nanotubes, the DC resistance is the smallest and the magnification Best performance and cycle performance. And when the second conductive agent is carbon fiber or carbon nanotube, the breaking elongation of the positive electrode is the longest. This may be because the one-dimensional structure of carbon fiber and carbon nanotube can stabilize the structure.
  • Example 14 The preparation parameters and performance test results of Examples 14 to 22 are shown in Table 5 and Table 6. The remaining preparation parameters not shown are the same as Example 1.
  • the negative electrode of the electrochemical device adopts the pole piece proposed in this application. It can be seen from Examples 14 to 18 that the mass percentage of the negative active material in the negative active material layer and the conductive agent are controlled. Mass percentage, composition of conductive agent, number of carbon nanotubes in carbon nanotube aggregates, diameter of carbon nanotubes, length of carbon nanotubes, thickness of negative active material layer, porosity of negative active material layer Within the range shown in Examples 14 to 18, the requirements for the bending radius and fracture elongation of the negative electrode can be met, and lower DC resistance, better rate performance and cycle performance can be obtained.
  • Comparative Examples 1 to 3 the positive and negative electrodes of the electrochemical device do not use the pole pieces proposed in this application. From Comparative Examples 1 to 3, it can be seen that the bending radius of the negative electrode is not less than 3 mm, and the fracture elongation of the negative electrode is None are greater than 1.9%, which indicates that the flexibility of the negative electrode is poor, and the DC resistance in Comparative Examples 1 to 3 is large, the 3C rate performance is poor, and the cycle performance is poor. This may be because the binder was added to Comparative Examples 1 to 3, which deteriorated the kinetic properties, resulting in reduced rate performance and cycle performance.

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Abstract

Des modes de réalisation de la présente invention concernent un appareil électrochimique et un appareil électronique. L'appareil électrochimique comprend une électrode, l'électrode comprenant une couche de matériau actif, le rayon de courbure de l'électrode étant de 0,5 à 1,5 mm, et l'allongement à la rupture de l'électrode étant de 2 à 8 %. Dans la présente invention, l'électrode présente une bonne flexibilité et une bonne adaptabilité à la déformation, et peut satisfaire aux exigences d'appareils électrochimiques flexibles.
PCT/CN2022/079668 2022-03-08 2022-03-08 Appareil électrochimique et appareil électronique WO2023168584A1 (fr)

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CN202280005101.0A CN115843395A (zh) 2022-03-08 2022-03-08 电化学装置和电子装置

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WO2013094100A1 (fr) * 2011-12-22 2013-06-27 パナソニック株式会社 Electrode positive pour batteries secondaires, et batterie secondaire utilisant celle-ci
CN105514488A (zh) * 2016-01-19 2016-04-20 宁德新能源科技有限公司 一种粘结剂及其锂离子电池
CN111244456A (zh) * 2020-01-16 2020-06-05 东莞市沃泰通新能源有限公司 高倍率磷酸铁锂电池
CN112703619A (zh) * 2018-10-03 2021-04-23 大金工业株式会社 正极结构体和二次电池
CN112768626A (zh) * 2021-01-25 2021-05-07 欣旺达电动汽车电池有限公司 正极极片及其制备方法和固态电池
WO2022035606A1 (fr) * 2020-08-12 2022-02-17 Cabot Corporation Compositions contenant du noir de carbone, du graphite et des nanotubes de carbone, électrodes associées et batteries associées

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101855753A (zh) * 2009-02-02 2010-10-06 松下电器产业株式会社 非水电解质二次电池及非水电解质二次电池的制造方法
WO2013094100A1 (fr) * 2011-12-22 2013-06-27 パナソニック株式会社 Electrode positive pour batteries secondaires, et batterie secondaire utilisant celle-ci
CN105514488A (zh) * 2016-01-19 2016-04-20 宁德新能源科技有限公司 一种粘结剂及其锂离子电池
CN112703619A (zh) * 2018-10-03 2021-04-23 大金工业株式会社 正极结构体和二次电池
CN111244456A (zh) * 2020-01-16 2020-06-05 东莞市沃泰通新能源有限公司 高倍率磷酸铁锂电池
WO2022035606A1 (fr) * 2020-08-12 2022-02-17 Cabot Corporation Compositions contenant du noir de carbone, du graphite et des nanotubes de carbone, électrodes associées et batteries associées
CN112768626A (zh) * 2021-01-25 2021-05-07 欣旺达电动汽车电池有限公司 正极极片及其制备方法和固态电池

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