WO2023184230A1 - 一种正极及使用其的电化学装置及电子装置 - Google Patents

一种正极及使用其的电化学装置及电子装置 Download PDF

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Publication number
WO2023184230A1
WO2023184230A1 PCT/CN2022/084045 CN2022084045W WO2023184230A1 WO 2023184230 A1 WO2023184230 A1 WO 2023184230A1 CN 2022084045 W CN2022084045 W CN 2022084045W WO 2023184230 A1 WO2023184230 A1 WO 2023184230A1
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Prior art keywords
functional layer
active material
positive electrode
electrochemical device
binder
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PCT/CN2022/084045
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English (en)
French (fr)
Inventor
陈梅锋
刘晓欠
韩冬冬
刘胜奇
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宁德新能源科技有限公司
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Application filed by 宁德新能源科技有限公司 filed Critical 宁德新能源科技有限公司
Priority to PCT/CN2022/084045 priority Critical patent/WO2023184230A1/zh
Priority to CN202280010594.7A priority patent/CN116783726A/zh
Publication of WO2023184230A1 publication Critical patent/WO2023184230A1/zh

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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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • 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

Definitions

  • the present application relates to the field of energy storage, and specifically to a positive electrode and an electrochemical device and electronic device using the positive electrode.
  • lithium-ion batteries With the popularity of electronic products such as laptops, mobile phones, handheld game consoles, and tablet computers, safety requirements for electrochemical devices (such as lithium-ion batteries) are becoming more and more stringent.
  • the production process of lithium-ion batteries inevitably involves the slitting process and compaction process of positive or negative electrodes.
  • current collectors are metal foils such as copper foil, aluminum foil or stainless steel. During the slitting process, these metal foils are affected by their intrinsic mechanical properties and the state of the slitting equipment, leaving defects such as metal burrs at the slitting area.
  • the present application relates to an electrochemical device, which includes a positive electrode.
  • the positive electrode includes: a positive electrode current collector and a film layer located on the surface of the positive electrode current collector; the film layer includes a positive electrode active material layer and A functional layer located between the positive electrode current collector and the positive electrode active material layer; the bonding force between the positive electrode active material layer and the functional layer is F1N/m, and the functional layer and the positive electrode collector The bonding force between fluids is F2N/m and satisfies 0.1 ⁇ F1/F2 ⁇ 0.5.
  • the adhesion between the cathode active material layer and the functional layer can be ensured. It is not much weaker than the adhesion between the functional layer and the current collector. When externally squeezed, it can reduce the risk of falling off between the positive active material layer and the functional layer, and prevent internal short circuits caused by the falling off of the positive active material layer.
  • F1/F2 ⁇ 0.5 can ensure that the functional layer can better extend with the positive electrode current collector when it is squeezed from the outside, thereby reducing the risk of metal burrs piercing the isolation film and causing internal short circuits, thereby reducing the risk of internal short circuits caused by metal burrs. Improve the safety performance of electrochemical devices.
  • F1 within the above range can further ensure the adhesion between the positive active material layer and the functional layer, reduce the risk of falling off between the positive active material layer and the functional layer when being squeezed from the outside, thereby improving the safety of the electrochemical device. performance.
  • F2 50 ⁇ F2 ⁇ 300.
  • F2 is within the above range, it can further reduce the risk of the functional layer and the positive electrode current collector falling off, improve the ductility of the functional layer with the positive electrode current collector, and reduce the risk of metal burrs piercing the isolation film and causing an internal short circuit when being squeezed from the outside.
  • the thickness of the functional layer is T1 ⁇ m
  • the thickness of the positive active material layer is T2 ⁇ m, satisfying 0.5 ⁇ T1 ⁇ 10; 5 ⁇ T2/T1 ⁇ 20.
  • T1 is within the above range, it can improve the shielding effect of the functional layer on metal burrs, thereby reducing the risk of metal burrs piercing the isolation film and causing an internal short circuit when being squeezed from the outside; at the same time, when T2/T1 is within the above range, it can make The thickness of the functional layer and the thickness of the cathode active material layer are more matched, so that while the electrochemical device has a better energy density, the safety performance is also further improved, so that the electrochemical device has better overall performance.
  • the weight loss rate of the film layer at 600°C is A% measured by thermogravimetric analysis under a nitrogen atmosphere.
  • the resistance of the positive electrode is R ⁇ , which satisfies the following At least one of the conditions: (I) 0.1A ⁇ R ⁇ 10A; (II) 1 ⁇ A ⁇ 20; (III) 10 ⁇ R ⁇ 50.
  • the derivative thermogravimetric analysis curve of the film layer has a first peak in the range of 300°C to 400°C and a second peak in the range of 410°C to 600°C, and the area of the first peak The area ratio to the second peak is X, satisfying 0.1 ⁇ X ⁇ 0.5.
  • the binder in the functional layer has high thermal stability and can inhibit the functional layer from falling off the positive electrode current collector at high temperatures, thereby further improving the safety performance of the electrochemical device.
  • the weight loss rate of the functional layer at 600°C is (100-A1)%, and the weight loss rate of the cathode active material layer at 600°C is (100 -A2)%, satisfying at least one of the following conditions: (i) 80 ⁇ A1 ⁇ 95; (ii) 95 ⁇ A2 ⁇ 99; (iii) 1 ⁇ A2/A1 ⁇ 1.3.
  • the functional layer includes first particles, a first conductive agent, and a first binder.
  • the first particles include a first metal element including at least one of Al, Mg, Ca, Ti, Ce, Zn, Y, Hf, Zr, Ba, Sn or Ni.
  • a first metal element including at least one of Al, Mg, Ca, Ti, Ce, Zn, Y, Hf, Zr, Ba, Sn or Ni.
  • the first conductive agent includes at least one of graphene, carbon nanotubes, carbon black, graphite fiber, or conductive carbon, wherein based on the quality of the functional layer, the first conductive agent The mass percentage is b%, satisfying 0.3 ⁇ b ⁇ 5.
  • the functional layer further includes third particles, the third particles include lithium and a second metal element, the second metal element includes at least one of Fe, Mn, Al, Mg, Co or Ni.
  • the mass percentage of the third particles is c%, satisfying 40 ⁇ c ⁇ 94.5.
  • the first binder includes a polymer formed from at least one of acrylic acid, acrylamide, acrylate, acrylonitrile or acrylate, wherein, based on the quality of the functional layer, the The mass percentage of a binder is d%, satisfying 3 ⁇ d ⁇ 15.
  • the first adhesive is an aqueous adhesive.
  • the functional layer further includes a leveling agent
  • the leveling agent includes silicone compounds, oxygen-containing olefin polymers, carboxylate compounds, carboxylate ester compounds, alcohol compounds, At least one of ether compounds or fluorocarbon compounds, the mass percentage of the leveling agent is less than or equal to 1% based on the mass of the functional layer.
  • the first particles comprise aluminum oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, boehmite , at least one of aluminum hydroxide, magnesium hydroxide, calcium hydroxide, diaspore, barium sulfate, calcium sulfate or calcium silicate; the third particle includes lithium iron phosphate, lithium iron manganese phosphate, lithium cobalt oxide , at least one of lithium manganate or lithium nickel cobalt manganate.
  • the positive active material layer includes a second binder, the second binder has a different composition from the first binder, and based on the quality of the functional layer, the first binder
  • the mass percentage content of the second binder is W1%, based on the mass of the cathode active material layer, the mass percentage content of the second binder is W2%, W2 ⁇ W1.
  • the cathode active material layer includes an active material, a second conductive agent, and a second binder, wherein the mass percentage of the active material is 95% to 95% based on the mass of the cathode active material layer. 98.5%, the mass percentage of the second conductive agent is 0.5% to 2%, and the mass percentage of the second binder is 1% to 3%.
  • the second binder includes at least one of polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene-hexafluoropropylene, sodium polyacrylate, nitrile rubber, or polyacrylate.
  • the present application relates to an electronic device comprising an electrochemical device according to any of the preceding embodiments.
  • a list of items connected by the term "at least one of,” “at least one of,” “at least one of,” or other similar terms may mean that the listed items any combination of.
  • the phrase “at least one of A and B” means only A; only B; or A and B.
  • the phrase “at least one of A, B, and C” means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B and C.
  • Item A may contain a single component or multiple components.
  • Item B may contain a single component or multiple components.
  • Item C may contain a single component or multiple components.
  • the present application provides an electrochemical device, which includes a positive electrode.
  • the positive electrode includes: a positive electrode current collector and a film layer located on the surface of the positive electrode current collector; the film layer includes a positive electrode active material layer and a positive electrode current collector located on the surface of the positive electrode current collector.
  • the functional layer between the positive active material layers; the adhesive force between the positive active material layer and the functional layer is F1N/m, and the adhesive force between the functional layer and the positive current collector is F2N/m, satisfying 0.1 ⁇ F1/F2 ⁇ 0.5.
  • the adhesion between the cathode active material layer and the functional layer can be ensured. It is not much weaker than the adhesion between the functional layer and the current collector. When externally squeezed, it can reduce the risk of falling off between the positive active material layer and the functional layer, and prevent internal short circuits caused by the falling off of the positive active material layer.
  • F1/F2 ⁇ 0.5 can ensure that the functional layer can better extend with the positive electrode current collector when it is squeezed from the outside, thereby reducing the risk of metal burrs piercing the isolation film and causing internal short circuits, thereby reducing the risk of internal short circuits caused by metal burrs. Improve the safety performance of electrochemical devices.
  • F1/F2 may be 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5 or a range between any two of the aforementioned values.
  • F1 within the above range can further ensure the adhesion between the positive active material layer and the functional layer and reduce the risk of falling off between the positive active material layer and the functional layer when being squeezed from the outside; at the same time, it can also reduce its impact on the functional layer.
  • the functional layer expands with the positive current collector, thereby improving the safety performance of the electrochemical device.
  • F1 may be 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30 or a range between any two of the aforementioned values.
  • F2 50 ⁇ F2 ⁇ 300.
  • F2 When F2 is within the above range, it can further reduce the risk of the functional layer and the positive electrode current collector falling off, improve the ductility of the functional layer with the positive electrode current collector, and reduce the risk of metal burrs piercing the isolation film and causing an internal short circuit when being squeezed from the outside.
  • F2 may be 50, 75, 100, 125, 150, 175, 200, 225, 250, 275, 300 or a range between any two of the aforementioned values.
  • the thickness of the functional layer is T1 ⁇ m
  • the thickness of the positive active material layer is T2 ⁇ m, satisfying 0.5 ⁇ T1 ⁇ 10; 5 ⁇ T2/T1 ⁇ 20.
  • T1 is within the above range, it can improve the shielding effect of the functional layer on metal burrs, thereby reducing the risk of metal burrs piercing the isolation film and causing an internal short circuit when being squeezed from the outside; at the same time, when T2/T1 is within the above range, it can make The thickness of the functional layer and the thickness of the cathode active material layer are more matched, so that while the electrochemical device has a better energy density, the safety performance is also further improved, so that the electrochemical device has better overall performance.
  • T1 may be 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 5, 5.5, 6, 7, 8, 9, 10 or a range between any two of the aforementioned values.
  • the weight loss rate of the film layer at 600°C is A% measured by thermogravimetric analysis under a nitrogen atmosphere.
  • the resistance of the positive electrode is R ⁇ , which satisfies the following At least one of the conditions: (I) 0.1A ⁇ R ⁇ 10A; (II) 1 ⁇ A ⁇ 20; (III) 10 ⁇ R ⁇ 50.
  • the derivative thermogravimetric analysis curve of the film layer has a first peak in the range of 300°C to 400°C and a second peak in the range of 410°C to 600°C, and the area of the first peak
  • the area ratio to the second peak is X, satisfying 0.1 ⁇ X ⁇ 0.5.
  • the weight loss rate of the functional layer at 600°C is (100-A1)%, and the weight loss rate of the cathode active material layer at 600°C is (100 -A2)%, satisfying at least one of the following conditions: (i) 80 ⁇ A1 ⁇ 95; (ii) 95 ⁇ A2 ⁇ 99; and (iii) 1 ⁇ A2/A1 ⁇ 1.3.
  • the functional layer is at 600°C, the organic compounds, such as binders, in the functional layer are removed, and the remaining substances are inorganic particles.
  • A1 in the above range can improve the stiffness of the functional layer, thereby improving the puncture resistance of the functional layer. , improve the safety performance of electrochemical devices.
  • the organic compounds, such as binders, in the positive active material layer are removed, and the remaining substances are positive active material particles.
  • A2 in the above range can make the electrochemical device have higher performance. Energy Density.
  • the cathode active layer has appropriate stiffness and can be better combined with the functional layer during cold pressing, further reducing the risk of the cathode active material layer falling off and causing internal short circuits when subjected to external extrusion. risks of.
  • the functional layer includes first particles, a first conductive agent, and a first binder.
  • the functional layer contains the first particles, the first conductive agent and the first binder, the functional layer can have good safety performance while controlling the resistance of the functional layer, so that the electrochemical device has good rate performance and low temperature at the same time. performance and safety features.
  • the first particles include a first metal element including at least one of Al, Mg, Ca, Ti, Ce, Zn, Y, Hf, Zr, Ba, Sn or Ni.
  • a first metal element including at least one of Al, Mg, Ca, Ti, Ce, Zn, Y, Hf, Zr, Ba, Sn or Ni.
  • the first conductive agent includes at least one of graphene, carbon nanotubes, carbon black, graphite fiber, or conductive carbon, wherein based on the quality of the functional layer, the first conductive agent The mass percentage is b%, satisfying 0.3 ⁇ b ⁇ 5.
  • the functional layer further includes third particles, the third particles include lithium and a second metal element, the second metal element includes at least one of Fe, Mn, Al, Mg, Co or Ni.
  • the mass percentage of the third particles is c%, satisfying 40 ⁇ c ⁇ 94.5.
  • the first binder includes a polymer formed from at least one of acrylic acid, acrylamide, acrylate, acrylonitrile or acrylate, wherein, based on the quality of the functional layer, the The mass percentage of a binder is d%, satisfying 3 ⁇ d ⁇ 15.
  • the first adhesive is an aqueous adhesive.
  • the water-based binder helps to improve the adhesion between the functional layer and the cathode current collector, allowing the functional layer to better adhere to the surface of the current collector, which can better improve the safety performance of the electrochemical device.
  • the functional layer further includes a leveling agent
  • the leveling agent includes silicone compounds, oxygen-containing olefin polymers, carboxylate compounds, carboxylate ester compounds, alcohol compounds, At least one of ether compounds or fluorocarbon compounds, the mass percentage of the leveling agent is less than or equal to 1% based on the mass of the functional layer.
  • the first particles comprise aluminum oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, ceria, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, bohm oxide At least one of stone, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, diaspore, barium sulfate, calcium sulfate or calcium silicate; the third particle includes lithium iron phosphate, lithium iron manganese phosphate, cobalt acid At least one of lithium, lithium manganate or lithium nickel cobalt manganate.
  • the second binder has a different composition from the first binder, and based on the quality of the functional layer, the first binder
  • the mass percentage content of the second binder is W1%, based on the mass of the cathode active material layer, the mass percentage content of the second binder is W2%, W2 ⁇ W1.
  • the positive active material layer includes an active material, a second conductive agent, and a second binder, wherein the mass percentage of the active material is 95% to 98.5 based on the mass of the positive active material layer. %, the mass percentage of the second conductive agent is 0.5% to 2%, and the mass percentage of the binder is 1% to 3%.
  • the second binder includes at least one of polyacrylic acid, polyvinylidene fluoride, polytetrafluoroethylene-hexafluoropropylene, sodium polyacrylate, nitrile rubber, or polyacrylate.
  • the side extrusion pass rate of the electrochemical device is ⁇ 80%. In some embodiments, the side extrusion pass rate of the electrochemical device is ⁇ 90%. In some embodiments, the side extrusion pass rate of the electrochemical device is ⁇ 94%. In some embodiments, the side extrusion pass rate of the electrochemical device is ⁇ 96%.
  • the electrochemical device of the present application includes, but is not limited to: all types of primary batteries and secondary batteries.
  • the electrochemical device is a lithium secondary battery.
  • lithium secondary batteries include, but are not limited to: lithium metal secondary batteries, lithium ion secondary batteries, or lithium ion polymer secondary batteries.
  • the electrochemical device of the present application also includes a separator, an electrolyte and a negative electrode.
  • the preparation method of the electrochemical device of the present application is described in detail below by taking a lithium-ion battery as an example.
  • Preparation of the negative electrode Disperse the negative electrode active material (at least one of carbon material, silicon material or lithium titanate) and the negative electrode binder in the solvent system according to a certain mass ratio, stir thoroughly and mix evenly, and then apply it to the negative electrode current collector. After drying and cold pressing, the negative electrode is obtained.
  • the negative electrode active material at least one of carbon material, silicon material or lithium titanate
  • First slurry (1) Add the first particle and/or the third particle, the first conductive agent and the first binder, and optional leveling agent to the solvent and mix evenly to obtain the slurry of the functional layer (hereinafter referred to as "First slurry");
  • step (3) Drying the positive electrode current collector containing the first slurry obtained in step (2) to remove the solvent to obtain the positive electrode current collector coated with the functional layer;
  • the positive electrode active material at least one of lithium cobalt oxide, lithium manganate or lithium iron phosphate
  • the second conductive agent at least one of lithium cobalt oxide, lithium manganate or lithium iron phosphate
  • the second binder in the solvent system according to a certain mass ratio and stir thoroughly to mix evenly. , obtaining a slurry of the positive electrode active material (hereinafter referred to as "second slurry");
  • step (6) Dry the positive electrode current collector containing the second slurry in step (5) to remove the solvent, thereby obtaining the desired positive electrode.
  • the second conductive agent improves the conductivity of the cathode active material layer by providing a conductive path to the active material.
  • the second conductive agent may include at least one of the following: acetylene black, Ketjen black, natural graphite, carbon black, carbon fiber, metal powder or metal fiber (such as copper, nickel, aluminum or silver), but the second conductive agent Examples of the second conductive agent are not limited to these.
  • the amount of the second conductive agent can be appropriately adjusted. Based on 100 parts by weight of the total amount of the cathode active material, the second conductive agent and the second binder, the amount of the second conductive agent ranges from 1 to 30 parts by weight.
  • examples of the solvent include, but are not limited to, N-methylpyrrolidone, acetone, or water. In some embodiments, the amount of solvent can be adjusted appropriately.
  • the second binder may assist in bonding between the active material and the second conductive agent, or assist in bonding between the active material and the current collector.
  • the second binder include, but are not limited to, polyvinylidene fluoride, polyvinylidene chloride, carboxymethylcellulose, polyvinyl acetate, polyvinylpyrrolidone, polypropylene, polyethylene, and various polymers.
  • the amount of the second binder ranges from 1 to 30 parts by weight based on 100 parts by weight of the total amount of the active material, the second conductive agent and the second binder.
  • the current collector has a thickness in the range of 3 microns to 20 microns, although the disclosure is not limited thereto.
  • the current collector is electrically conductive and does not cause adverse chemical changes in the manufactured battery.
  • Examples of the current collector include copper, stainless steel, aluminum, nickel, titanium, or alloys (eg, copper-nickel alloys), but the disclosure is not limited thereto.
  • fine irregularities eg, surface roughness
  • the current collector can be used in various forms, and examples thereof include films, sheets, foils, meshes, porous structures, foams, or similar materials, but the disclosure is not limited thereto.
  • Isolation film In some embodiments, a polyethylene (PE) porous polymer film is used as the isolation film.
  • the material of the isolation membrane may include fiberglass, polyester, polyethylene, polypropylene, polytetrafluoroethylene or combinations thereof.
  • the pores in the isolation film have a diameter in the range of 0.01 micron to 1 micron, and the thickness of the isolation film ranges from 5 microns to 500 microns.
  • the electrolyte includes an organic solvent, a lithium salt, and additives.
  • the organic solvent includes ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate At least one of ester or ethyl propionate.
  • the lithium salt includes at least one of an organic lithium salt or an inorganic lithium salt.
  • lithium salts include lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium difluorophosphate (LiPO 2 F 2 ), lithium bistrifluoromethanesulfonimide LiN (CF 3 SO 2 ) 2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N(SO 2 F) 2 )(LiFSI), lithium bis(fluorosulfonyl)borate LiB(C 2 O 4 ) 2 (LiBOB), lithium difluoroxalatoborate At least one of LiBF 2 (C 2 O 4 ) (LiDFOB).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiPO 2 F 2 lithium difluorophosphate
  • LiN CF 3 SO 2 ) 2
  • LiTFSI lithium bis(fluorosulfonyl)imide Li(N(
  • the bare battery core obtained by winding is placed in an outer package, electrolyte is injected and packaged, and a lithium-ion battery is obtained through processes such as formation, degassing, and trimming.
  • the present application provides an electronic device comprising the electrochemical device according to the foregoing content.
  • the electronic devices 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, head-mounted Stereo headphones, 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, lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries or lithium-ion capacitors, etc.
  • Step (1) Add the first particle and/or the third particle, the first conductive agent, the first binder, and the optional leveling agent to deionized water and mix evenly to obtain the slurry of the functional layer (in the following called "first slurry”);
  • Step (2) Apply the first slurry in step (1) to the target area of the positive electrode current collector;
  • Step (3) Dry the positive electrode current collector containing the first slurry in step (2) to remove the solvent, and obtain the positive electrode current collector coated with the functional layer;
  • Step (4) Disperse the cathode active material, conductive material, and second binder in the N-methylpyrrolidone solvent system and mix thoroughly to obtain a slurry of the cathode active material (hereinafter referred to as "second slurry”). ");
  • Step (5) Coating the second slurry on the target area of the positive electrode current collector coated with the functional layer obtained in step (3);
  • Step (6) Dry the positive electrode current collector containing the second slurry in step (5) to remove the solvent, thereby obtaining the desired positive electrode.
  • the second conductive agent in the positive active material layer is carbon nanotube (CNT) and conductive carbon (SP), the second binder is polyvinylidene fluoride (PVDF), and the positive active material is lithium cobalt oxide (LCO), based on the weight of the positive active material layer, the content of CNT is 0.5%, the content of SP is 0.6%, the content of PVDF is 1.3%, the content of the positive active material is 97.6%, and the thickness of the positive active material layer is 50 ⁇ m .
  • CNT carbon nanotube
  • SP conductive carbon
  • PVDF polyvinylidene fluoride
  • LCO lithium cobalt oxide
  • the first particle is boehmite (B1)
  • the first binder is a polymer polymerized by 45% acrylonitrile, 45% lithium acrylate, and 10% acrylamide
  • the first conductive agent is conductive carbon ( SP)
  • the content ratio of the first particles, the first binder and the first conductive agent is as shown in Table 1.
  • the thickness of the functional layer is 3 ⁇ m.
  • Table 1 below specifically shows the composition differences between the functional layer and the positive electrode active material layer in the positive electrodes in Examples 1 to 46 and Comparative Examples 1 to 4.
  • Negative electrode Combine the active material artificial graphite, the conductive agent acetylene black, the binder styrene-butadiene rubber (SBR), and the thickener carbon methylcellulose sodium (CMC) in a deionized state at a mass ratio of approximately 95:2:2:1. After thoroughly stirring and mixing in the water solvent system, it is coated on a Cu foil, dried, and cold pressed to obtain a negative electrode.
  • SBR binder styrene-butadiene rubber
  • CMC thickener carbon methylcellulose sodium
  • Electrolyte In an argon atmosphere glove box with a water content of ⁇ 10 ppm, mix ethylene carbonate (abbreviated as EC), diethyl carbonate (abbreviated as DEC), and propylene carbonate (abbreviated as PC) according to 2:6: Mix evenly at a weight ratio of 2, and then dissolve the fully dried lithium salt LiPF 6 in the above solvent. The content of LiPF 6 is 12.5%. Add 1.5% 1,3-propane sultone and 3% fluoroethylene carbonate. , 2% adiponitrile. The content of each substance is based on the total weight of the electrolyte.
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • PC propylene carbonate
  • Isolation film PE porous polymer film is used as the isolation film.
  • the positive electrode, isolation film, and negative electrode in order, so that the isolation film is between the positive and negative electrodes for isolation, roll it up, place it in the outer package, inject the prepared electrolyte and package it, and then form and degas , trimming and other processes to obtain the battery.
  • the battery In an environment of (25 ⁇ 3)°C, the battery is charged with a constant current of 0.5C until the voltage is 4.45V, then changed to a constant voltage charge to a cut-off current of 0.05C, and then fully discharged with a constant current of 0.2C to 3.0V. , to obtain a capacity of 0.2C at room temperature; charge the battery with a constant current of 0.5C until the voltage is 4.45V, then change to constant voltage charging to a cut-off current of 0.05C, and place the battery in an environment of (-20 ⁇ 3)°C 60min, and then use 0.2C constant current to fully discharge to 3.0V to obtain 0.2C low temperature capacity.
  • Low temperature performance 0.2C low temperature capacity/0.2C normal temperature capacity ⁇ 100%
  • Table 2 below shows various properties of Examples 1 to 46 and Comparative Examples 1 to 4.
  • the peak area ratio in Table 2 is the area ratio of the first peak in the range of 300°C to 400°C and the second peak in the range of 410°C to 600°C in the differential thermogravimetric analysis curve of the film layer.
  • F1/F2 ⁇ 0.5 can ensure that when being squeezed from the outside, The functional layer can better extend with the cathode current collector, thereby reducing the risk of metal burrs piercing the isolation film and causing internal short circuits, thereby improving the safety performance of the electrochemical device.
  • This application has discovered through research that if the thickness T1 of the functional layer is too large (for example, greater than 10 ⁇ m), it will unreasonably reduce the energy density of the electrochemical device. If the thickness T1 of the functional layer is too thin (for example, less than 0.5 ⁇ m), coating leakage will easily occur.
  • T1 When T1 is within the above range, it can improve the shielding effect of the functional layer on metal burrs, thereby reducing the risk of metal burrs piercing the isolation film and causing an internal short circuit when being squeezed from the outside; at the same time, when T2/T1 is within the above range, it can make The thickness of the functional layer is more consistent with the thickness of the positive active material layer, which reduces the risk of the positive active material layer falling off when squeezed from the outside, further improving the safety performance of the electrochemical device.
  • the T2/T1 of Example 26 is 50, and the screw extrusion pass rate of the lithium ion battery prepared therefrom is 6/10, which is significantly lower than the screw extrusion pass rates of other examples.
  • the functional layer of the present application including first particles (insulating particles), first conductive agents (conductive particles) and third particles (particles that can be used as positive active materials) can further improve the screw extrusion pass rate of the electrochemical device.
  • first particles insulating particles
  • first conductive agents conductive particles
  • third particles particles that can be used as positive active materials
  • the first particles of Examples 1 to 46 use boehmite and alumina
  • the first conductive agent uses conductive carbon Super P, carbon nanotubes (CNT), and carbon fiber
  • the third particles use LFP (lithium iron phosphate) and LMFP (lithium iron manganese phosphate) can both achieve ideal screw extrusion pass rates.
  • the third particles contained in the functional layer can also be used as positive active materials, thereby further increasing the energy density of the electrochemical device.
  • the composition of the functional layer of the present application is not limited to the types specifically listed in the embodiments, wherein the first particles may include aluminum oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, At least one of nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttria, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, diaspore, barium sulfate, calcium sulfate or calcium silicate, And the third particles may include at least one of lithium iron phosphate, lithium iron manganese phosphate, lithium cobalt oxide, lithium manganate or lithium nickel cobalt manganate.
  • the first binder used in the functional layer in Examples 1 to 46 of the present application is acrylonitrile, acrylate, and acrylamide polymer
  • the second binder used in the positive active material layer is PVDF, polyacrylic acid, and nitrile rubber.
  • the mass percentage of the first binder is W1%
  • the mass percentage of the second binder is W2 %, where W2 ⁇ W1.
  • the adhesive used in this application is not limited to the types listed in the specific embodiments. Those skilled in the art can think of using a variety of suitable binder combinations based on the inventive concept of the present application.
  • the differential thermogravimetric analysis curve of the functional layer and the cathode active material layer of the present application has a first peak in the range of 300°C to 400°C and a second peak in the range of 410°C to 600°C, where the area of the first peak
  • the area ratio to the second peak is X, which satisfies 0.1 ⁇ X ⁇ 0.5.
  • the first peak represents the first binder in the functional layer
  • the second peak represents the second binder in the cathode active material layer.
  • the leveling agent used in the functional layers in Examples 1 to 46 of the present application is a silicone compound. It should be understood that it can also be at least one of oxygen-containing olefin polymers, carboxylate compounds, carboxylic ester compounds, alcohol compounds, ether compounds, or fluorocarbon compounds, and based on the functional layer Mass, the mass percentage of the leveling agent is 0.01% to 0.5%.
  • the addition of leveling agent is conducive to forming a uniform and smooth functional layer, increasing the contact area between the functional layer and the current collector and active material layer, increasing the adhesion, and thus improving the safety performance of the electrochemical device.
  • the electrochemical device of the present application has a high screw extrusion pass rate and maintains good electrochemical performance.
  • references throughout this specification to “some embodiments,” “partial embodiments,” “one embodiment,” “another example,” “example,” “specific example,” or “partial example” mean the following: At least one embodiment or example in this application includes a specific feature, structure, material or characteristic described in the embodiment or example. Accordingly, phrases such as “in some embodiments,” “in an embodiment,” “in one embodiment,” “in another example,” “in one example,” etc. may appear in various places throughout this specification. "in”, “in a particular example” or “for example” do not necessarily refer to the same embodiment or example in this application. Furthermore, the specific features, structures, materials, or characteristics herein may be combined in any suitable manner in one or more embodiments or examples.

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Abstract

本申请公开一种电化学装置，其包含正极，所述正极包括：正极集流体和位于所述正极集流体表面的膜层；所述膜层包括正极活性材料层和位于所述正极集流体与所述正极活性材料层之间的功能层。所述正极活性材料层与所述功能层之间的粘结力为F1N/m，所述功能层与所述正极集流体之间的粘结力为F2N/m，通过满足0.1≤F1/F2≤0.5，能够显著提升电化学装置的安全性能。

Description

一种正极及使用其的电化学装置及电子装置 技术领域
本申请涉及储能领域，具体涉及一种正极及使用该正极的电化学装置及电子装置。
背景技术
随着电子产品如笔记本电脑、手机、掌上游戏机和平板电脑等的普及，人们对电化学装置(例如，锂离子电池)的安全性要求也越来越严格。锂离子电池在生产过程中不可避免涉及正极或负极的分切工序和压实工序。一般集流体为铜箔、铝箔或不锈钢等金属箔，这些金属箔材在分切过程中受本征机械性能和分切设备状态的影响，会在分切处留下金属毛刺等瑕疵。这种金属毛刺如不处理，在锂离子电池受到外部挤压时，将刺穿隔离膜，从而导致正极、负极内短路，最终导致电池发热冒烟或起火爆炸等严重后果。
发明内容
根据本申请的一方面，本申请涉及一种电化学装置，其包含正极，所述正极包括：正极集流体和位于所述正极集流体表面的膜层；所述膜层包括正极活性材料层和位于所述正极集流体与所述正极活性材料层之间的功能层；所述正极活性材料层与所述功能层之间的粘结力为F1N/m，所述功能层与所述正极集流体之间的粘结力为F2N/m，满足0.1≤F1/F2≤0.5。
通过在正极集流体和正极活性材料层之间设置功能层，并使F1/F2在上述范围内，一方面，F1/F2≥0.1，能够保证正极活性材料层与功能层之间的粘结性不比功能层与集流体之间的粘结性弱太多，在受到外部挤压时，可以降低正极活性材料层与功能层之间脱落的风险，防止由于正极活性材料层的脱落导致内短路的发生；另一方面，F1/F2≤0.5，能够确保在受到外部挤压时，功能层能够更好地随着正极集 流体进行延展，从而降低金属毛刺刺穿隔离膜导致内短路的风险，进而提高电化学装置的安全性能。
在一些实施例中，10≤F1≤30。F1在上述范围，能够进一步确保正极活性材料层与功能层之间的粘结性，降低在受到外部挤压时，正极活性材料层与功能层之间脱落的风险，进而提高电化学装置的安全性能。
在一些实施例中，50≤F2≤300。F2在上述范围内，能够进一步降低功能层与正极集流体脱落的风险，提高功能层随正极集流体的延展性，在受到外部挤压时，降低金属毛刺刺穿隔离膜导致内短路的风险。
在一些实施例中，所述功能层的厚度为T1μm，所述正极活性材料层的厚度为T2μm，满足0.5≤T1≤10；5≤T2/T1≤20。T1在上述范围内，能够提高功能层对金属毛刺的遮蔽作用，从而降低在受到外部挤压时，金属毛刺刺穿隔离膜导致内短路的风险；同时，T2/T1在上述范围内，能够使功能层的厚度和正极活性材料层的厚度更匹配，使得电化学装置在具有较优的能量密度的同时，安全性能也得到进一步提升，使电化学装置具有较优的综合性能。
在一些实施例中，所述膜层氮气氛下通过热重分析检测在600℃时的失重率为A％，所述电化学装置在满充状态下，所述正极的电阻为RΩ，满足如下条件中的至少一者：(I)0.1A≤R≤10A；(II)1≤A≤20；(III)10≤R≤50。
在一些实施例中，所述膜层的微商热重分析曲线在300℃至400℃范围内有第一峰且在410℃至600℃范围内有第二峰，所述第一峰的面积与所述第二峰的面积比为X，满足0.1≤X≤0.5。此时，功能层中的粘结剂具有较高的热稳定性，能够抑制高温下功能层与正极集流体的脱落，从而进一步提高电化学装置的安全性能。
在一些实施例中，氮气氛下通过热重分析检测，所述功能层在600℃时的失重率为(100-A1)％，所述正极活性材料层在600℃时的失重率为(100-A2)％，满足如下条件中的至少一者：(i)80≤A1≤95；(ii)95≤A2≤99；(iii)1≤A2/A1＜1.3。
在一些实施例中，所述功能层包含第一颗粒、第一导电剂、第一粘结剂。
在一些实施例中，所述第一颗粒包含第一金属元素，所述第一金属元素包含Al、 Mg、Ca、Ti、Ce、Zn、Y、Hf、Zr、Ba、Sn或Ni中的至少一种，其中基于所述功能层的质量，所述第一颗粒的质量百分比为a％，满足1≤a≤40。
在一些实施例中，所述第一导电剂包含石墨烯、碳纳米管、碳黑、石墨纤维或导电碳中的至少一种，其中，基于所述功能层的质量，所述第一导电剂的质量百分比为b％，满足0.3≤b≤5。
在一些实施例中，所述功能层还包含第三颗粒，所述第三颗粒包含锂以及第二金属元素，所述第二金属元素包含Fe、Mn、Al、Mg、Co或Ni中的至少一种，其中，基于所述功能层的质量，所述第三颗粒的质量百分比为c％，满足40≤c≤94.5。
在一些实施例中，所述第一粘结剂包含丙烯酸、丙烯酰胺、丙烯酸盐、丙烯腈或丙烯酸酯中的至少一种形成的聚合物，其中，基于所述功能层的质量，所述第一粘结剂的质量百分比为d％，满足3≤d≤15。
在一些实施例中，所述第一粘结剂为水性粘结剂。
在一些实施例中，所述功能层还包含流平剂，所述流平剂包含硅氧烷类化合物、含氧烯烃聚合物、羧酸盐类化合物、羧酸酯类化合物、醇类化合物、醚类化合物、或氟碳化合物中的至少一种，基于所述功能层的质量，所述流平剂的质量百分比小于或等于1％。
在一些实施例中，所述第一颗粒包含氧化铝、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、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙、水铝石、硫酸钡、硫酸钙或硅酸钙中的至少一种；所述第三颗粒包含磷酸铁锂、磷酸锰铁锂、钴酸锂、锰酸锂或镍钴锰酸锂中的至少一种。
在一些实施例中，所述正极活性材料层包括第二粘结剂，所述第二粘结剂与第一粘结剂组成不同，基于所述功能层的质量，所述第一粘结剂的质量百分含量为W1％，基于所述正极活性材料层的质量，所述第二粘结剂的质量百分含量为W2％，W2＜W1。
在一些实施例中，所述正极活性材料层包含活性材料、第二导电剂和第二粘结剂，其中，基于所述正极活性材料层的质量，所述活性材料的质量百分比为95％至 98.5％，所述第二导电剂的质量百分比为0.5％至2％，所述第二粘结剂的质量百分比为1％至3％。
在一些实施例中，所述第二粘结剂包含聚丙烯酸、聚偏氟乙烯、聚四氟乙烯-六氟丙烯、聚丙烯酸钠、丁腈橡胶或聚丙烯酸酯中的至少一种。
根据本申请的另一方面，本申请涉及包含根据前述任一实施例所述的电化学装置的电子装置。
具体实施方式
下文中，对本申请进行详细说明。应当理解，在说明书和所附权利要求中使用的术语不应被解释为限于一般和词典的含义，而是在发明人被允许适当定义术语以进行最佳解释的原则的基础上基于与本申请的技术方面相对应的含义和概念来解释。因此，说明书中所述的实施方案中所示的描述仅仅是用于说明的目的的具体实例，而不旨在显示本申请的所有技术方面，并且应当理解，在提交本申请时可以对其完成多种可选等价体和变体。
在具体实施方式及权利要求书中，由术语“中的至少一者”、“中的至少一个”、“中的至少一种”或其他相似术语所连接的项目的列表可意味着所列项目的任何组合。例如，如果列出项目A及B，那么短语“A及B中的至少一者”意味着仅A；仅B；或A及B。在另一实例中，如果列出项目A、B及C，那么短语“A、B及C中的至少一者”意味着仅A；或仅B；仅C；A及B(排除C)；A及C(排除B)；B及C(排除A)；或A、B及C的全部。项目A可包含单个元件或多个元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。
另外，有时在本文中以范围格式呈现量、比率和其它数值。应理解，此类范围格式是用于便利及简洁起见，且应灵活地理解，不仅包含明确地指定为范围限制的数值，而且包含涵盖于所述范围内的所有个别数值或子范围，如同明确地指定每一数值及子范围一般。
一、电化学装置
本申请提供一种电化学装置，其包含正极，所述正极包括：正极集流体和位于 所述正极集流体表面的膜层；所述膜层包括正极活性材料层和位于所述正极集流体与所述正极活性材料层之间的功能层；所述正极活性材料层与所述功能层之间的粘结力为F1N/m，所述功能层与所述正极集流体之间的粘结力为F2N/m，满足0.1≤F1/F2≤0.5。
通过在正极集流体和正极活性材料层之间设置功能层，并使F1/F2在上述范围内，一方面，F1/F2≥0.1，能够保证正极活性材料层与功能层之间的粘结性不比功能层与集流体之间的粘结性弱太多，在受到外部挤压时，可以降低正极活性材料层与功能层之间脱落的风险，防止由于正极活性材料层的脱落导致内短路的发生；另一方面，F1/F2≤0.5，能够确保在受到外部挤压时，功能层能够更好地随着正极集流体进行延展，从而降低金属毛刺刺穿隔离膜导致内短路的风险，进而提高电化学装置的安全性能。
在一些实施例中，0.12≤F1/F2≤0.4。在一些实施例中，0.15≤F1/F2≤0.3。在一些实施例中，F1/F2可为0.1、0.11、0.12、0.13、0.14、0.15、0.16、0.17、0.2、0.25、0.3、0.35、0.4、0.45、0.5或前述任意两数值之间的范围。
在一些实施例中，10≤F1≤30。F1在上述范围，能够进一步确保正极活性材料层与功能层之间的粘结性，降低在受到外部挤压时，正极活性材料层与功能层之间脱落的风险；同时，也能够降低其对功能层随正极集流体延展的影响，进而提高电化学装置的安全性能。在一些实施例中，15≤F1≤25。在一些实施例中，F1可为10、12、14、15、16、18、20、22、24、25、26、28、30或前述任意两数值之间的范围。
在一些实施例中，50≤F2≤300。F2在上述范围内，能够进一步降低功能层与正极集流体脱落的风险，提高功能层随正极集流体的延展性，在受到外部挤压时，降低金属毛刺刺穿隔离膜导致内短路的风险。在一些实施例中，100≤F2≤250。在一些实施例中，F2可为50、75、100、125、150、175、200、225、250、275、300或前述任意两数值之间的范围。
在一些实施例中，所述功能层的厚度为T1μm，所述正极活性材料层的厚度为 T2μm，满足0.5≤T1≤10；5≤T2/T1≤20。T1在上述范围内，能够提高功能层对金属毛刺的遮蔽作用，从而降低在受到外部挤压时，金属毛刺刺穿隔离膜导致内短路的风险；同时，T2/T1在上述范围内，能够使功能层的厚度和正极活性材料层的厚度更匹配，使得电化学装置在具有较优的能量密度的同时，安全性能也得到进一步提升，使电化学装置具有较优的综合性能。在一些实施例中，1≤T1≤8。在一些实施例中，1.5≤T1≤6。在一些实施例中，2≤T1≤5。在一些实施例中，T1可为0.5、1.0、1.5、2.0、2.5、3.0、3.5、4.0、5、5.5、6、7、8、9、10或前述任意两数值之间的范围。在一些实施例中，7≤T2/T1≤19。在一些实施例中，10≤T2/T1≤18。
在一些实施例中，所述膜层氮气氛下通过热重分析检测在600℃时的失重率为A％，所述电化学装置在满充状态下，所述正极的电阻为RΩ，满足如下条件中的至少一者：(I)0.1A≤R≤10A；(II)1≤A≤20；(III)10≤R≤50。
在一些实施例中，所述膜层的微商热重分析曲线在300℃至400℃范围内有第一峰且在410℃至600℃范围内有第二峰，所述第一峰的面积与所述第二峰的面积比为X，满足0.1≤X≤0.5。
在一些实施例中，氮气氛下通过热重分析检测，所述功能层在600℃时的失重率为(100-A1)％，所述正极活性材料层在600℃时的失重率为(100-A2)％，满足如下条件中的至少一者：(i)80≤A1≤95；(ii)95≤A2≤99；和(iii)1≤A2/A1＜1.3。所述功能层在600℃时，功能层中的有机化合物，如粘结剂被去除，剩余物质为无机颗粒，A1在上述范围，能够提高功能层的刚度，进而提高功能层的防刺穿性，提高电化学装置的安全性能。所述正极活性材料层在600℃时，所述正极活性材料层中有机化合物，如粘结剂被去除，剩余物质为正极活性材料颗粒，A2在上述范围，能够使得电化学装置具有较高的能量密度。进一步地，当A2/A1在上述范围时，正极活性层具有合适的刚度，在冷压时能够与功能层更好地结合，进一步降低在受到外部挤压时，正极活性材料层脱落导致内短路的风险。
在一些实施例中，所述功能层包含第一颗粒、第一导电剂、第一粘结剂。当功能层包含第一颗粒、第一导电剂和第一粘结剂时，能够使功能层具有良好的安全性 能的同时，控制功能层的电阻，使电化学装置同时具有良好的倍率性能、低温性能和安全性能。
在一些实施例中，所述第一颗粒包含第一金属元素，所述第一金属元素包含Al、Mg、Ca、Ti、Ce、Zn、Y、Hf、Zr、Ba、Sn或Ni中的至少一种，其中，基于所述功能层的质量，所述第一颗粒的质量百分比为a％，满足1≤a≤40。
在一些实施例中，所述第一导电剂包含石墨烯、碳纳米管、碳黑、石墨纤维或导电碳中的至少一种，其中，基于所述功能层的质量，所述第一导电剂的质量百分比为b％，满足0.3≤b≤5。
在一些实施例中，所述功能层还包含第三颗粒，所述第三颗粒包含锂以及第二金属元素，所述第二金属元素包含Fe、Mn、Al、Mg、Co或Ni中的至少一种，其中，基于所述功能层的质量，所述第三颗粒的质量百分比为c％，满足40≤c≤94.5。
在一些实施例中，所述第一粘结剂包含丙烯酸、丙烯酰胺、丙烯酸盐、丙烯腈或丙烯酸酯中的至少一种形成的聚合物，其中，基于所述功能层的质量，所述第一粘结剂的质量百分比为d％，满足3≤d≤15。
在一些实施例中，所述第一粘结剂为水性粘结剂。水性粘结剂有助于提高功能层与正极集流体的粘结性，使功能层能够更好的粘附在集流体表面，能够更好的改善电化学装置的安全性能。
在一些实施例中，所述功能层还包含流平剂，所述流平剂包含硅氧烷类化合物、含氧烯烃聚合物、羧酸盐类化合物、羧酸酯类化合物、醇类化合物、醚类化合物、或氟碳化合物中的至少一种，基于所述功能层的质量，所述流平剂的质量百分比小于或等于1％。
在一些实施例中，其中所述第一颗粒包含氧化铝、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、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙、水铝石、硫酸钡、硫酸钙或硅酸钙中的至少一种；所述第三颗粒包含磷酸铁锂、磷酸锰铁锂、钴酸锂、锰酸锂或镍钴锰酸锂中的至少一种。
在一些实施例中，其中所述正极活性材料层包括第二粘结剂，所述第二粘结剂 与第一粘结剂组成不同，基于所述功能层的质量，所述第一粘结剂的质量百分含量为W1％，基于所述正极活性材料层的质量，所述第二粘结剂的质量百分含量为W2％，W2＜W1。
在一些实施例中，所述正极活性材料层包含活性材料、第二导电剂和第二粘结剂，其中基于所述正极活性材料层的质量，所述活性材料的质量百分比为95％至98.5％，所述第二导电剂的质量百分比为0.5％至2％，所述粘结剂的质量百分比为1％至3％。
在一些实施例中，所述第二粘结剂包含聚丙烯酸、聚偏氟乙烯、聚四氟乙烯-六氟丙烯、聚丙烯酸钠、丁腈橡胶或聚丙烯酸酯中的至少一种。
在一些实施例中，所述电化学装置的侧边挤压通过率≥80％。在一些实施例中，所述电化学装置的侧边挤压通过率≥90％。在一些实施例中，所述电化学装置的侧边挤压通过率≥94％。在一些实施例中，所述电化学装置的侧边挤压通过率≥96％。
在一些实施例中，本申请的电化学装置包括，但不限于：所有种类的一次电池、二次电池。在一些实施例中，所述电化学装置是锂二次电池。在一些实施例中，锂二次电池包括，但不限于：锂金属二次电池、锂离子二次电池或锂离子聚合物二次电池。
本申请的电化学装置还包括隔离膜、电解液和负极。
二、一种制备前述电化学装置的方法
如下以锂离子电池为例详细描述了本申请的电化学装置的制备方法。
负极的制备：将负极活性物质(碳材料、硅材料或钛酸锂中至少一种)和负极粘结剂按一定的质量比分散于溶剂体系中充分搅拌混合均匀后，涂覆于负极集流体上，经过烘干、冷压，得到负极。
正极的制备：
(1)将第一颗粒和/或第三颗粒、第一导电剂和第一粘结剂，可选的流平剂，加入溶剂中混合均匀，获得功能层的浆料(在后称作“第一浆料”)；
(2)将步骤(1)中的第一浆料涂覆在正极集流体的目标区域；
(3)将步骤(2)中的获得的含有第一浆料的正极集流体进行烘干以去除溶剂，得到涂有功能层的正极集流体；
(4)将正极活性物质(钴酸锂、锰酸锂或磷酸铁锂中的至少一种)、第二导电剂、第二粘结剂按一定的质量比分散于溶剂体系中充分搅拌混合均匀，得到正极活性物质的浆料(在后称作“第二浆料”)；
(5)将第二浆料涂覆在步骤(3)中得到的涂有功能层的正极集流体的目标区域；
(6)将步骤(5)中的含有第二浆料的正极集流体进行烘干以去除溶剂，从而得到所要正极。
在一些实施例中，第二导电剂以通过向活性物质提供导电路径来改善所述正极活性材料层的导电性。所述第二导电剂可以包括如下中的至少一种：乙炔黑、科琴黑、天然石墨、炭黑、碳纤维、金属粉末或金属纤维(例如铜、镍、铝或银)，但所述第二导电剂的示例并不限于此。在一些实施例中，可适宜的调节第二导电剂的量。基于100重量份的正极活性物质、第二导电剂和第二粘结剂的总量，所述第二导电剂的量的范围为1至30重量份。
在一些实施例中，所述溶剂的示例包括但不限于N-甲基吡咯烷酮、丙酮或水。在一些实施例中，可适当的调节溶剂的量。
在一些实施例中，所述第二粘结剂可以帮助所述活性物质和所述第二导电剂之间的粘结，或者帮助所述活性物质和所述集流体之间的粘结。所述第二粘结剂的示例包括但不限于聚偏氟乙烯、聚偏氯乙烯、羧甲基纤维素、聚乙酸乙烯酯、聚乙烯基吡咯烷酮、聚丙烯、聚乙烯和各种聚合物。基于100重量份的活性物质、第二导电剂和第二粘结剂的总量，所述第二粘结剂的量的范围为1至30重量份。
在一些实施例中，所述集流体具有3微米至20微米范围内的厚度，但本公开内容不限于此。所述集流体是导电的，且不在所制造的电池中引起不利的化 学变化。所述集流体的实施例包括铜、不锈钢、铝、镍、钛或合金(例如铜-镍合金)，但不公开内容不限于此。在一些实施例中，所述集流体的表面上可包括细小的不规则物(例如，表面粗糙度)以增强所述集流体的表面对活性物质的粘合。在一些实施例中，集流体可以多种形式使用，其实施例包括膜、片、箔、网、多孔结构体、泡沫体或无妨物，但本公开内容不限于此。
隔离膜：在一些实施例中，以聚乙烯(PE)多孔聚合薄膜作为隔离膜。在一些实施例中，所述隔离膜的材质可包括玻璃纤维，聚酯，聚乙烯，聚丙烯，聚四氟乙烯或其组合。在一些实施例中，所述隔离膜中的孔具有在0.01微米至1微米范围的直径，所述隔离膜的厚度在5微米至500微米范围内。
电解液：在一些实施例中，所述电解液包括有机溶剂、锂盐和添加剂。在一些实施例中，有机溶剂包括碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)、碳酸甲乙酯(EMC)、碳酸二甲酯(DMC)、碳酸亚丙酯或丙酸乙酯中的至少一种。在一些实施例中，锂盐包括有机锂盐或无机锂盐中的至少一种。在一些实施例中，锂盐包括六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、二氟磷酸锂(LiPO 2F 2)、双三氟甲烷磺酰亚胺锂LiN(CF 3SO 2) 2(LiTFSI)、双(氟磺酰)亚胺锂Li(N(SO 2F) 2)(LiFSI)、双草酸硼酸锂LiB(C 2O 4) 2(LiBOB)、二氟草酸硼酸锂LiBF 2(C 2O 4)(LiDFOB)中的至少一种。
将正极、隔离膜、负极按顺序叠好，使隔离膜处于正负极中间起到隔离的作用，并卷绕得到裸电芯。将经卷绕所得裸电芯置于外包装中，注入电解液并封装，经过化成、脱气、切边等工艺流程获得锂离子电池。
三、电子装置
本申请提供了一种电子装置，其包含根据前述内容所述的电化学装置。
根据本申请的一些实施例，所述电子装置包括，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、家庭用大型蓄电池或锂离子电容器等。
三、具体的实施例
下面结合实施例，对本申请做进一步详细的描述。然而，应理解，以下实施例仅是示例，本申请的实施例方式不限于此。
实施例1至46和对比例1至4
步骤(1)：将第一颗粒和/或第三颗粒、第一导电剂、第一粘结剂，可选的流平剂，加入去离子水中混合均匀，获得功能层的浆料(在后称作“第一浆料”)；
步骤(2)：将步骤(1)中的第一浆料涂覆在正极集流体的目标区域；
步骤(3)：将步骤(2)中的含有第一浆料的正极集流体进行烘干以去除溶剂，得到涂有功能层的正极集流体；
步骤(4)：将正极活性物质、导电材料、第二粘结剂分散于N-甲基吡咯烷酮溶剂体系中充分搅拌混合均匀，得到正极活性物质的浆料(在后称作“第二浆料”)；
步骤(5)：将第二浆料涂覆在步骤(3)中得到的涂有功能层的正极集流体的目标区域；
步骤(6)：将步骤(5)中的含有第二浆料的正极集流体进行烘干以去除溶剂，从而得到所要正极。
在实施例1中，正极活性材料层中第二导电剂为碳纳米管(CNT)和导电碳(SP)，第二粘结剂为聚偏氟乙烯(PVDF)，正极活性物质为钴酸锂(LCO)，基于正极活性材料层的重量，CNT的含量为0.5％，SP的含量为0.6％，PVDF的含量为1.3％，正极活性物质的含量为97.6％，正极活性材料层的厚度为50μm。功能层中，第一颗粒为勃姆石(B1)，第一粘结剂为45％丙烯腈、45％丙烯酸锂、10％丙烯酰胺聚合而成的聚合物，第一导电剂为导电碳(SP)，基于功能层的重量，第一颗粒、第一粘结剂和第一导电剂含量比例如表1所示。功能层的厚度 为3μm。
如下表1具体示出了实施例1至46和对比例1至4中的正极中功能层和正极活性材料层的成分差异。
表1
Figure PCTCN2022084045-appb-000001
Figure PCTCN2022084045-appb-000002
Figure PCTCN2022084045-appb-000003
Figure PCTCN2022084045-appb-000004
除上述差异外，实施例1至46与对比例1至4中的负极、电解液、隔离膜等并没有差异，均采用如下工艺制备。
负极：将活性物质人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂碳甲基纤维素钠(CMC)按照质量比约为95∶2∶2∶1在去离子水溶剂体系中充分搅拌混合均匀后，涂覆于Cu箔上烘干、冷压，得到负极。
电解液：在含水量＜10ppm的氩气气氛手套箱中，将碳酸乙烯酯(简写为EC)、碳酸二乙酯(简写为DEC)、碳酸丙烯酯(简写为PC)、按照2∶6∶2的重量比混合均匀，再将充分干燥的锂盐LiPF 6溶解于上述溶剂，LiPF 6的含量为12.5％，加入1.5％的1，3-丙烷磺内酯、3％的氟代碳酸乙烯酯、2％的己二腈。其中各物质含量是以电解液的总重量计。
隔离膜：以PE多孔聚合薄膜作为隔离膜。
将正极、隔离膜、负极按顺序叠好，使隔离膜处于正负极中间起到隔离的作用，并卷绕、置于外包装中，注入配好的电解液并封装，经过化成，脱气，切边等工艺得到电池。
性能测试方法
粘结力
1)取样：在(25±3)℃的环境下，将涂有功能层的正极从锂离子电池中拆出，用无尘纸拭去正极表面残留的电解液；
2)制样：取待测试极片，用刀片截取宽x(20mm)及长y(190mm)的试样，尺寸可依据实际拆出极片尺寸选择；
3)将双面胶贴于宽度30mm×长度200mm钢板上，双面胶宽度20mm×长度y(190mm)；
4)将第2步截取的极片试样的正极活性材料层贴在双面胶上，测试面朝下；
5)将钢板和极片试样用夹具固定，用高铁AI-3000拉力机测试其粘结力，拉伸速度：50mm/min，拉伸位移可根据样品长度确定；
7)根据曲线走平时的拉力值f1(N)计算正极活性材料层与功能层之间的粘结力F1＝f1/x(极片宽度)，单位：N/m。
8)将剥离正极活性材料层的极片试样重复上述步骤，将功能层贴在双面胶上，根据曲线走平时的拉力值f2(N)计算功能层与正极集流体之间的粘结力F2＝f2/x(极片宽度)，单位：N/m。
功能层/正极活性材料层厚度
1)在(25±3)℃的环境下，将涂有功能层的正极从锂离子电池中拆出。用无尘纸拭去正极表面残留的电解液；
2)在等离子体下切割涂有功能层的正极，得到其横截面；
3)在扫描电镜(SEM)下观察2)中得到的正极的横截面，并测量功能层的厚度Tμm，相邻测试点间隔约2mm至3mm，至少测量15个不同点，所有测量点的均值记为功能层的厚度T1μm；正极活性材料层的厚度T2μm的测量方法与之相同。
满充状态下的正极电阻
1)0.05C的倍率恒流充电至满充设计电压4.45V，之后改为满充设计电压恒压充电至电流为0.025C(截止电流)，使锂离子电池达到满充状态；
2)将锂离子电池拆解，得到正极；
3)将2)中所得正极在湿度为约5％至约15％的环境中放置30min，然后密封转移到电阻测试地点；
4)使用BER1200型号膜片电阻测试仪测试3)中所得正极的电阻，相邻测试点间隔2mm至3mm，至少测试15个不同点，所有测试点的电阻均值记为满充状态下的正极电阻R，其中测试参数为：压头面积153.94mm 2，压力3.5t，保持时间50s。
螺钉挤压测试
1)电池长宽面朝上，放置于两个平行板内；
2)在电池表面中心处放置一颗螺纹直径为2mm，螺丝长度为4mm，头部直径为3.8mm，头部厚度为1.3mm的螺丝(0#螺丝)；
3)垂直于平行板的方向施压，两平行板间施加约13±1kN的挤压力，一旦压力达到最大值即可停止挤压，保持时间3min；以电池不起火、不爆炸为通过测试，取10支电池进行平行实验，螺钉挤压通过率＝通过量/10。
倍率性能(2C/0.2C)测试
在(25±3)℃的环境下，电池用0.5C电流进行恒流充电至电压为4.45V，之后改为恒压充电至截止电流0.05C，然后分别用0.2C和2C恒流进行满放电至3.0V，分别得到0.2C和2C的放电容量，倍率性能＝2C放电容量/0.2C放电容量×100％。
低温性能测试
在(25±3)℃的环境下，电池用0.5C电流进行恒流充电至电压为4.45V，之后改为恒压充电至截止电流0.05C，然后用0.2C恒流进行满放电至3.0V，得到0.2C常温容量；将电池用0.5C电流进行恒流充电至电压为4.45V，之后改为恒压充电至截止电流0.05C，将电池静置于(-20±3)℃的环境下60min，然后用0.2C恒流进行满放电至3.0V，得到0.2C低温容量，低温性能＝0.2C低温容量/0.2C常温容量×100％
热重分析方法：
1.取适量样品置于坩埚中；
2.编辑测试程序，升温速率设置10℃/min，测试温度区间设置25-600℃；气氛为氮气氛；
3.运行程序，测试结束后即可得到TG、DSC曲线；根据TG、DSC曲线即可获得相应的失重率以及峰面积比。
如下表2示出了实施例1至46和对比例1至4的各项性能。
表2
Figure PCTCN2022084045-appb-000005
Figure PCTCN2022084045-appb-000006
Figure PCTCN2022084045-appb-000007
注：表2中峰面积比值为膜层的微商热重分析曲线在300℃至400℃范围内的第一峰与在410℃至600℃范围内的第二峰的面积比。
1.探讨功能层的有无
由上述表1和表2可知，具有功能层的实施例1至46以及具有功能层的对比例2至4的锂离子电池的螺钉挤压通过率明显优于没有功能层的对比例1的锂离子电池的螺钉挤压通过率。由此可见，正极集流体与正极活性材料层之间设置功能层可以显著提高电化学装置的螺钉挤压通过率。
2.探讨正极活性材料层与功能层、功能层与正极集流体之间的粘结力
由上述表1和表2可知，当正极活性材料层与所述功能层之间的粘结力F1(N/m)，功能层与所述正极集流体之间的粘结力为F2(N/m)满足0.1≤F1/F2≤0.5时，相应锂离子电池的螺钉挤压透过率显著提高。这主要是因为，一方面，F1/F2≥0.1，能够保证正极活性材料层与功能层之间的粘结性不比功能层与集流体之间的粘结性弱太多，在受到外部挤压时，可以降低正极活性材料层与功能层之间脱落的风险，防止由于正极活性材料层的脱落导致内短路的发生；另一方面，F1/F2≤0.5，能够确保在受到外部挤压时，功能层能够更好地随着正极集流体进行延展，从而降低金属毛刺刺穿隔离膜导致内短路的风险，进而提高电化学装置的安全性能。
3.探讨功能层的厚度
由上述表1和表2中的实施例1-25至27-46可知，当功能层的厚度T1(以μm 计)与正极活性材料层的厚度T2(以μm计)满足0.5≤T1≤10和5≤T2/T1≤20时，电化学装置可以具有较高的螺钉挤压通过率。
本申请经过研究发现，功能层的厚度T1太大(例如，大于10μm)会不合理的降低电化学装置的能量密度。功能层的厚度T1太薄(例如，小于0.5μm)则会容易出现漏涂。T1在上述范围内，能够提高功能层对金属毛刺的遮蔽作用，从而降低在受到外部挤压时，金属毛刺刺穿隔离膜导致内短路的风险；同时，T2/T1在上述范围内，能够使功能层的厚度和正极活性材料层的厚度更匹配，降低在受到外部挤压时，正极活性材料层脱落的风险，进一步提升电化学装置的安全性能。例如，实施例26的T2/T1为50，由其制备的锂离子电池的螺钉挤压通过率为6/10，显著低于其它实施例的螺钉挤压通过率。
4.功能层中的第一颗粒、第二颗粒和第三颗粒
包含第一颗粒(绝缘颗粒)、第一导电剂(导电颗粒)和第三颗粒(可用作正极活性材料的颗粒)的本申请功能层可以进一步提高电化学装置的螺钉挤压通过率。结合表1和表2可知，实施例1至46的第一颗粒采用勃姆石、氧化铝，第一导电剂采用了导电碳Super P、碳纳米管(CNT)、碳纤维，第三颗粒采用LFP(磷酸铁锂)、LMFP(磷酸锰铁锂)其均可以获得理想的螺钉挤压通过率。另外，功能层中包含的第三颗粒还可以用作正极活性材料，从而进一步增加电化学装置的能量密度。
另外，应当理解，本申请的功能层的组成不限于实施例所具体列举的种类，其中所述第一颗粒可包含氧化铝、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、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙、水铝石、硫酸钡、硫酸钙或硅酸钙中的至少一种，且所述第三颗粒可包含磷酸铁锂、磷酸锰铁锂、钴酸锂、锰酸锂或镍钴锰酸锂中的至少一种。
5.粘结剂
本申请实施例1至46中的功能层所用的第一粘结剂为丙烯腈、丙烯酸盐、丙烯酰胺聚合物，正极活性材料层所用的第二粘结剂为PVDF、聚丙烯酸、丁腈橡胶、聚四氟乙烯-六氟丙烯，基于功能层的质量，第一粘结剂的质量百分含量为W1％， 基于正极活性材料层的质量，第二粘结剂的质量百分含量为W2％，其中W2＜W1。通过对第一粘结剂和第二粘结剂的种类以及含量的设计，可以制备满足前述粘结力要求的正极。
另外，应当理解，本申请所用的粘结剂不限于具体实施例所列举的种类。本领域技术人员可以基于本申请的发明构思想到采用多种合适的粘结剂组合。
6.热重分析
本申请功能层和正极活性材料层的微商热重分析曲线在300℃至400℃范围内有第一峰且在410℃至600℃范围内有第二峰，其中所述第一峰的面积与所述第二峰的面积比为X，其中满足0.1≤X≤0.5。其中，第一峰代表功能层中的第一粘结剂，第二峰代表正极活性材料层中的第二粘结剂。通过面积比X在上述范围内，能够使得功能层均具有较好的热稳定性，能够抑制高温下功能层与正极集流体的脱落，进而提高电化学装置的安全性能。
7.流平剂
本申请实施例1至46中的功能层所用的流平剂为硅氧烷类化合物。应理解，其还可以为含氧烯烃聚合物、羧酸盐类化合物、羧酸酯类化合物、醇类化合物、醚类化合物、或氟碳化合物中的至少一种，且基于所述功能层的质量，所述流平剂的质量百分比为0.01％至0.5％。流平剂的加入，有利于形成均匀、平滑的功能层，增加功能层和集流体以及活性材料层的接触面积，增大粘结性，进而提高电化学装置的安全性能。
综上所述，本申请的电化学装置具有较高的螺钉挤压通过率且保持较好的电化学性能。
整个说明书中对“一些实施例”、“部分实施例”、“一个实施例”、“另一举例”、“举例”、“具体举例”或“部分举例”的引用，其所代表的意思是在本申请中的至少一个实施例或举例包含了该实施例或举例中所描述的特定特征、结构、材料或特性。因此，在整个说明书中的各处所出现的描述，例如：“在一些实施例中”、“在实施例中”、“在一个实施例中”、“在另一个举例中”，“在一个举例中”、“在特定举例中”或“举例“， 其不必然是引用本申请中的相同的实施例或示例。此外，本文中的特定特征、结构、材料或特性可以以任何合适的方式在一个或多个实施例或举例中结合。
尽管已经演示和描述了说明性实施例，本领域技术人员应该理解上述实施例不能被解释为对本申请的限制，并且可以在不脱离本申请的精神、原理及范围的情况下对实施例进行改变，替代和修改。

Claims (10)

  1. 一种电化学装置，其包含正极，所述正极包括：
    正极集流体和位于所述正极集流体表面的膜层；
    所述膜层包括正极活性材料层和位于所述正极集流体与所述正极活性材料层之间的功能层；
    其中，所述正极活性材料层与所述功能层之间的粘结力为F1N/m，所述功能层与所述正极集流体之间的粘结力为F2N/m，满足0.1≤F1/F2≤0.5。
  2. 根据权利要求1所述的电化学装置，其中，所述正极满足如下条件中的至少一者：
    (a)10≤F1≤30；
    (b)50≤F2≤300。
  3. 根据权利要求1所述的电化学装置，其中，所述功能层的厚度为T1μm，所述正极活性材料层的厚度为T2μm，满足0.5≤T1≤10；5≤T2/T1≤20。
  4. 根据权利要求1所述的电化学装置，其中，所述膜层氮气氛下通过热重分析检测在600℃时的失重率为A％，所述电化学装置在满充状态下，所述正极的电阻为RΩ，满足如下条件中的至少一者：(I)0.1A≤R≤10A；(II)1≤A≤20；(III)10≤R≤50。
  5. 根据权利要求1所述的电化学装置，其中，所述膜层的微商热重分析曲线在300℃至400℃范围内有第一峰且在410℃至600℃范围内有第二峰，所述第一峰的面积与所述第二峰的面积比为X，满足0.1≤X≤0.5。
  6. 根据权利要求1所述的电化学装置，其中，氮气氛下通过热重分析检测，所述功能层在600℃时的失重率为(100-A1)％，所述正极活性材料层在600℃时的失重率为(100-A2)％，满足如下条件中的至少一者：
    (i)80≤A1≤95；
    (ii)95≤A2≤99；
    (iii)1≤A2/A1＜1.3。
  7. 根据权利要求1所述的电化学装置，其中，所述功能层包含第一颗粒、第一导电剂、第一粘结剂，满足如下条件中的至少一者：
    (1)所述第一颗粒包含第一金属元素，所述第一金属元素包含Al、Mg、Ca、Ti、Ce、Zn、Y、Hf、Zr、Ba、Sn或Ni中的至少一种，其中，基于所述功能层的质量，所述第一颗粒的质量百分比为a％，满足1≤a≤40；
    (2)所述第一导电剂包含石墨烯、碳纳米管、碳黑、石墨纤维或导电碳中的至少一种，其中基于所述功能层的质量，所述第一导电剂的质量百分比为b％，满足0.3≤b≤5；
    (3)所述功能层还包含第三颗粒，所述第三颗粒包含锂以及第二金属元素，所述第二金属元素包含Fe、Mn、Al、Mg、Co或Ni中的至少一种，其中，基于所述功能层的质量，所述第三颗粒的质量百分比为c％，满足40≤c≤94.5；
    (4)所述第一粘结剂包含丙烯酸、丙烯酰胺、丙烯酸盐、丙烯腈或丙烯酸酯中的至少一种形成的聚合物，其中，基于所述功能层的质量，所述第一粘结剂的质量百分比为d％，满足3≤d≤15；
    (5)所述第一粘结剂为水性粘结剂；
    (6)所述功能层还包含流平剂，所述流平剂包含硅氧烷类化合物、含氧烯烃聚合物、羧酸盐类化合物、羧酸酯类化合物、醇类化合物、醚类化合物、或氟碳化合物中的至少一种，基于所述功能层的质量，所述流平剂的质量百分比小于或等于1％；
    (7)所述第一颗粒包含氧化铝、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、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙、水铝石、硫酸钡、硫酸钙或硅酸钙中的至少一种；所述第三颗粒包含磷酸铁锂、磷酸锰铁锂、钴酸锂、锰酸锂或镍钴锰酸锂中的至少一种。
  8. 根据权利要求7所述的电化学装置，其中，所述正极活性材料层包括第二粘结剂，所述第二粘结剂与所述第一粘结剂组成不同，基于所述功能层的质量，所述第一粘结剂的质量百分含量为W1％，基于所述正极活性材料层的质量，所述第二粘结剂的质量百分含量为W2％，W2＜W1。
  9. 根据权利要求1所述的电化学装置，其中，所述正极活性材料层包含活性材料、第二导电剂和第二粘结剂，满足如下条件中的至少一者：
    (7)基于所述正极活性材料层的质量，所述活性材料的质量百分比为95％至98.5％，所述第二导电剂的质量百分比为0.5％至2％，所述第二粘结剂的质量百分比为1％至3％；
    (8)所述第二粘结剂包含聚丙烯酸、聚偏氟乙烯、聚四氟乙烯-六氟丙烯、聚丙烯酸钠、丁腈橡胶或聚丙烯酸酯中的至少一种。
  10. 一种电子装置，其包含根据权利要求1-9中任一项所述的电化学装置。
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