WO2025199815A1 - 负极极片、负极极片的制备方法以及二次电池 - Google Patents

负极极片、负极极片的制备方法以及二次电池

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Publication number
WO2025199815A1
WO2025199815A1 PCT/CN2024/084168 CN2024084168W WO2025199815A1 WO 2025199815 A1 WO2025199815 A1 WO 2025199815A1 CN 2024084168 W CN2024084168 W CN 2024084168W WO 2025199815 A1 WO2025199815 A1 WO 2025199815A1
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WO
WIPO (PCT)
Prior art keywords
negative electrode
inorganic ceramic
active material
ceramic particles
electrode sheet
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Application number
PCT/CN2024/084168
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English (en)
French (fr)
Inventor
李志愿
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Ningde Amperex Technology Ltd
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Ningde Amperex Technology Ltd
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Publication date
Application filed by Ningde Amperex Technology Ltd filed Critical Ningde Amperex Technology Ltd
Priority to CN202480004077.8A priority Critical patent/CN121039822A/zh
Priority to PCT/CN2024/084168 priority patent/WO2025199815A1/zh
Publication of WO2025199815A1 publication Critical patent/WO2025199815A1/zh
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of battery technology, and in particular to a negative electrode sheet, a method for preparing a negative electrode sheet, and a secondary battery.
  • Secondary batteries such as lithium-ion batteries, have advantages such as high energy density, long cycle life, and high charge and discharge efficiency, and have been widely used around the world.
  • the present application provides a negative electrode sheet, a method for preparing a negative electrode sheet, and a secondary battery, which can improve both the energy density and kinetic performance of lithium-ion batteries.
  • the present application provides a negative electrode plate, which includes a negative electrode current collector and a negative electrode active material layer arranged on at least one surface of the negative electrode current collector, the negative electrode active material layer includes a negative electrode active material and an inorganic ceramic particle group, and the inorganic ceramic particles in the inorganic ceramic particle group are arranged on the surface of the negative electrode active material in the form of cluster aggregates (see the bright box mark in Figure 1).
  • the negative electrode plate when tested by a scanning electron microscope, within the range of 5 ⁇ m ⁇ 5 ⁇ m, the number of inorganic ceramic particle groups on the surface of the negative electrode active material particles is N', 3 ⁇ N' ⁇ 20.
  • the present application provides a negative electrode plate with cluster aggregates in the negative electrode plate.
  • inorganic ceramic particle groups attached to the surface of the negative electrode active material in the form of inorganic ceramic particle groups is conducive to improving the potential of the negative electrode, thereby improving the capacity of the negative electrode active material, thereby improving the energy density (ED) without changing the amount of active material.
  • ED energy density
  • lithium deposition is less likely to occur during charging (broadening the lithium deposition window), thereby taking into account the improvement of the kinetic performance of the lithium-ion battery.
  • the inorganic ceramic particles are attached to the surface of the negative electrode active material in the form of inorganic ceramic particle groups, which can avoid the obstruction of ion conduction caused by the distribution of a large number of single ceramic particles, and is more conducive to improving the kinetic performance of the lithium-ion battery.
  • different agglomeration states of the inorganic ceramic particle groups can be achieved by adjusting the stirring time. For example, for inorganic ceramic particles with a Dv50 of 5 nm and a W of 100 m 2 /g, when the addition amount is 0.1%, stirring for 30 minutes can achieve an N' of 1-3, stirring for 30 minutes to 1 hour can achieve an N' of 3-10, and stirring for 1-2 hours can achieve an N' of 10-20.
  • the particle size Dv50 of the inorganic ceramic particles is 2 nm to 20 nm.
  • Inorganic ceramic particles of the above particle size range are introduced into the negative electrode plate, and the cluster aggregates formed after aggregation are more conducive to improving the potential of the negative electrode.
  • Inorganic ceramic particles with a particle size Dv50 that is too small or too large are not conducive to forming a suitable number of cluster aggregates.
  • the particle size Dv50 of the inorganic ceramic particles is 5 nm to 15 nm.
  • the number of inorganic ceramic particles is N, where N>3. This can avoid the obstruction of ion conduction caused by the distribution of a large number of single ceramic particles.
  • Clusters of inorganic ceramic particles with N ⁇ 3 can be considered single ceramic particles.
  • the inorganic ceramic particles have a specific surface area W, W>50 m2 /g.
  • W specific surface area
  • W>50 m2 /g the specific surface area of the ceramic particles
  • the inorganic ceramic particle group formed after aggregation is more conducive to improving the potential of the negative electrode and more conducive to improving the energy density and dynamic performance of the lithium-ion battery.
  • the inorganic ceramic particles are selected from at least one of lithium fluoride, lithium sulfate, sodium titanate, calcium carbonate, calcium sulfate, calcium phosphate, aluminum hydroxide, aluminum oxide, aluminum sulfate, aluminum carbonate, magnesium hydroxide, magnesium oxide, magnesium sulfate, magnesium carbonate, or silicon oxide.
  • the weight percentage of the inorganic ceramic particles is 0.05 wt % to 0.3 wt % based on the weight of the negative electrode active material layer.
  • the inorganic ceramic particles are selected from any one of aluminum hydroxide, silicon dioxide, and magnesium hydroxide.
  • the thickness of the negative electrode sheet is 30 ⁇ m to 300 ⁇ m, and the thickness of the negative electrode current collector is 4 ⁇ m to 25 ⁇ m.
  • the present application provides a method for preparing a negative electrode sheet, comprising the following steps: mixing a negative electrode active material, inorganic ceramic particles, a binder and a dispersant, preparing an aqueous slurry with a solid content of 50% with deionized water, and stirring for 0.5h to 3h.
  • the mass ratio of the negative electrode active material, the inorganic ceramic particles, the dispersant, and the binder is (96-98):(0.1-0.5):(1-2):(1-2).
  • the present application provides a secondary battery, which includes any negative electrode sheet according to the first aspect; or, the secondary battery includes a negative electrode sheet prepared by any preparation method according to the second aspect.
  • FIG1 is a SEM test image of the negative electrode sheet in this application.
  • FIG2 is a SEM test image of the negative electrode sheet of Example 1 of the present application within a range of 5 ⁇ m ⁇ 5 ⁇ m;
  • a first aspect of an embodiment of the present application provides a negative electrode plate, which includes a negative electrode current collector and a negative electrode active material layer arranged on at least one surface of the negative electrode current collector, the negative electrode active material layer including a negative electrode active material and an inorganic ceramic particle group, the inorganic ceramic particles in the inorganic ceramic particle group being arranged on the surface of the negative electrode active material in the form of cluster aggregates.
  • the negative electrode plate when tested by a scanning electron microscope, within the range of 5 ⁇ m ⁇ 5 ⁇ m, the number of inorganic ceramic particle groups on the surface of the negative electrode active material particles is N′, 3 ⁇ N′ ⁇ 20.
  • a plurality of inorganic ceramic particle groups are arranged in the negative electrode plate and attached to the surface of the negative electrode active material in the form of cluster aggregates. At the same time, the number of inorganic ceramic particle groups on the surface of the negative electrode active material is controlled within the above-mentioned range.
  • the potential of the negative electrode can be increased, which is beneficial to improving the capacity of the negative electrode active material.
  • lithium deposition is less likely to occur during charging, which is beneficial to improving the kinetic performance.
  • the inorganic ceramic particles are attached to the surface of the negative electrode active material in the form of inorganic ceramic particle groups, which can avoid the obstruction of ion conduction caused by the distribution of a large number of single-particle ceramics (N ⁇ 3), and is more conducive to the improvement of kinetic performance, that is, taking into account the improvement of the energy density and kinetic performance of the lithium-ion battery.
  • the particle size Dv50 of the inorganic ceramic particles in the inorganic ceramic particle group is 2 nm to 20 nm.
  • Inorganic ceramic particles of the above particle size range are introduced into the negative electrode plate. After aggregation, it is more conducive to forming a suitable number of cluster aggregates (N>3) to improve the potential of the negative electrode.
  • the particle size Dv50 of the inorganic ceramic particles is 2 nm, 4 nm, 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, or a range consisting of any two of the above values.
  • the number of inorganic ceramic particles in the inorganic ceramic particle group is N, where N>3.
  • the inorganic ceramic particle group has a suitable secondary particle size, which is more conducive to improving the kinetic performance of lithium-ion batteries.
  • N ⁇ 6 in some embodiments, N ⁇ 10, in some embodiments, N ⁇ 15, and in some embodiments, N ⁇ 20.
  • the above is only an example and is not limited in this application.
  • the specific surface area of the inorganic ceramic particles in the inorganic ceramic particle group is W, where W>50 m2 /g.
  • W W>50 m2 /g.
  • the inorganic ceramic particle group formed after aggregation is more conducive to improving the potential of the negative electrode, while also improving the energy density and kinetic performance of the lithium-ion battery.
  • the inorganic ceramic particles are selected from lithium fluoride, lithium sulfate, sodium titanate, calcium carbonate, At least one of calcium sulfate, calcium phosphate, aluminum hydroxide, aluminum oxide, aluminum sulfate, aluminum carbonate, magnesium hydroxide, magnesium oxide, magnesium sulfate, magnesium carbonate, or silicon oxide, the mass percentage of the inorganic ceramic particles being 0.05wt% to 0.3wt% based on the mass of the negative electrode active material layer. When the mass percentage of the inorganic ceramic particles is within the above range, it is more conducive to improving the energy density and kinetic performance of the lithium-ion battery.
  • the mass percentage of the inorganic ceramic particles is 0.05wt%, 0.08wt%, 0.1wt%, 0.15wt%, 0.25wt%, 0.3wt%, or a range consisting of any two of the above values.
  • the thickness of the negative electrode active material layer is 30 ⁇ m to 300 ⁇ m.
  • the thickness of the negative electrode active material layer is 30 ⁇ m, 50 ⁇ m, 80 ⁇ m, 100 ⁇ m, 120 ⁇ m, 150 ⁇ m, 180 ⁇ m, 200 ⁇ m, 220 ⁇ m, 250 ⁇ m, 280 ⁇ m, 300 ⁇ m, or a range consisting of any two of the foregoing values.
  • the thickness of the negative electrode current collector is 4 ⁇ m to 25 ⁇ m.
  • the thickness of the negative electrode current collector is 4 ⁇ m, 6 ⁇ m, 8 ⁇ m, 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 25 ⁇ m, or a range consisting of any two of the above values.
  • the negative electrode active material is graphite, silicon or a mixture of silicon and graphite, wherein silicon is a mixture of pure silicon material, silicon alloy material, silicon-carbon composite material, silicon-oxygen material or one or more of the following.
  • the binder includes SBR (styrene-butadiene rubber), PAA (polyacrylic acid), PVA (polyvinyl alcohol), polyacrylate and other various or A dispersant includes an organic acid having a molecular weight of 10W or less, containing at least one of a hydroxyl group, an amino group, or an imino group, and being soluble in an aqueous solution having a pH of 7 or more and 13 or less.
  • Carboxymethyl cellulose (CMC) is preferably used as the dispersant.
  • the mass ratio of the negative electrode active material, the inorganic ceramic particles, the dispersant, and the binder is (96-98):(0.1-0.5):(1-2):(1-2).
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer arranged on the surface of the positive electrode current collector.
  • the present application has no special restrictions on the positive electrode current collector, as long as the purpose of the present application can be achieved.
  • it can include aluminum foil, aluminum alloy foil or a composite current collector (for example, a composite current collector with a metal layer arranged on the surface of a polymer layer).
  • the present application has no special restrictions on the thickness of the positive electrode current collector, as long as the purpose of the present application can be achieved.
  • the thickness of the positive electrode current collector is 5 ⁇ m to 13 ⁇ m.
  • the positive electrode active material layer includes a positive electrode active material.
  • the positive electrode active material may include a composite metal oxide containing one or more selected from the group consisting of cobalt, manganese, and nickel and lithium, or a lithium-containing olivine-type phosphate containing one or more selected from iron, cobalt, nickel, and manganese.
  • These positive electrode active materials may be used alone or in combination of two or more.
  • Part of these composite metal oxides with lithium or lithium-containing olivine-type phosphates can be replaced by other elements, or part of cobalt, nickel, manganese, and iron can be replaced by one or more elements selected from Co, Mn, Ni, Mg, Al, B, Ti, V, Nb, Cu, Zn, Mo, Ca, Sr, W, and Zr, or coated with compounds or carbon materials containing these other elements.
  • the present application has no particular restrictions on the thickness of the positive electrode active material layer, as long as the purpose of the present application can be achieved.
  • the thickness of the positive electrode active material layer is 30 ⁇ m to 120 ⁇ m.
  • the positive electrode active material layer may also include a conductive agent and a binder.
  • the present application has no particular restrictions on the types of the conductive agent and the binder, as long as the purpose of the present application can be achieved.
  • the conductive agent may include but is not limited to at least one of conductive carbon black, carbon nanotubes (CNTs), carbon fibers, Ketjen black, graphene, metal materials, or conductive polymers.
  • the binder may include, but is not limited to, at least one of polyacrylic acid, polyacrylate, acrylate polymer, polyvinyl alcohol, polyvinylidene fluoride, polytetrafluoroethylene, or vinylidene fluoride-hexafluoropropylene copolymer.
  • the present application does not particularly limit the mass ratio of the positive electrode active material, conductive agent, and binder in the positive electrode active material layer. Those skilled in the art may select the binder according to actual needs, as long as the purpose of the present application can be achieved.
  • the isolation membrane can be any known porous structure isolation membrane with electrochemical stability and chemical stability, such as a single layer or multilayer film of one or more of glass fiber, non-woven fabric, polyethylene (PE), polypropylene (PP) and polyvinylidene fluoride (PVDF).
  • PE polyethylene
  • PP polypropylene
  • PVDF polyvinylidene fluoride
  • the electrolyte includes an organic solvent, an electrolyte lithium salt and an additive.
  • the present invention does not impose any specific restrictions on the type of the electrolyte, and the electrolyte can be selected according to actual needs.
  • the organic solvent includes ethylene carbonate.
  • EC propylene carbonate
  • PC propylene carbonate
  • EMC diethyl carbonate
  • DMC dimethyl carbonate
  • DPC dipropyl carbonate
  • MPC methyl propyl carbonate
  • EPC ethyl propyl carbonate
  • BC butylene carbonate
  • FEC fluoroethylene carbonate
  • MF methyl formate
  • MA methyl acetate
  • EA propyl acetate
  • PA propyl acetate
  • PA methyl propionate
  • MP ethyl propionate
  • EP propyl propionate
  • PP methyl butyrate
  • EB ethyl butyrate
  • GBL 1,4-butyrolactone
  • SF sulfolane
  • MSM dimethyl sulfone
  • EMS ethyl methyl sulfone
  • ESE diethyl sulfone
  • MSM dimethyl sulfone
  • EMS ethyl methyl
  • the electrolyte may optionally include other additives, which may be any additive that can be used as a lithium-ion secondary battery.
  • the present invention is not specifically limited thereto and may be selected according to actual needs.
  • the additive may be one or more of vinylene carbonate (VC), vinyl ethylene carbonate (VEC), fluoroethylene carbonate (FEC), 1,3-propane sultone (PS), succinonitrile (SN), adiponitrile (ADN), 1,3-propylene sultone (PST), tris(trimethylsilyl) phosphate (TMSP) or tris(trimethylsilyl) borate (TMSB).
  • the structure of the lithium battery is not particularly limited, and a coin-type battery, a cylindrical battery, a square-type battery, a pouch battery, or the like having a single-layer or multi-layer separator can be applied.
  • the application of the lithium-ion battery of the present invention is not particularly limited and can be used in any battery known in the prior art.
  • Sub-device The application of the lithium-ion battery of the present invention is not particularly limited and can be used in any battery known in the prior art. Sub-device.
  • the lithium-ion battery of the present application can be used for, but is not limited to, laptop computers, pen-type computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, head-mounted stereo headphones, video recorders, LCD televisions, 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 fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.
  • Example 2 The difference between Examples 2 to 18 and Example 1 is that, during the preparation of the negative electrode sheet, the type of inorganic ceramic particles, particle size Dv50 and its specific surface area parameters are regulated, as shown in Table 1. At the same time, the number N' of the inorganic ceramic particle group and the number N of inorganic ceramic particles in the inorganic ceramic particle group are controlled by adjusting the stirring time of the aqueous slurry, as shown in Table 1. Other details are the same as in Example 1. For example, in Example 5, the ceramic Dv50 is 15 nm, W is 100 m 2 /g, and the stirring time is 1 hour. In Example 11, the ceramic Dv50 is 2 nm, W is 160 m 2 /g, and the stirring time is 3 hours.
  • the positive electrode active material, lithium cobalt oxide ( LiCoO2 ), conductive carbon black (Super P), and a binder (PVDF) were mixed to a weight ratio of 97.5:1.0:1.5.
  • NMP was then added as a solvent to create a slurry with a solids content of 75%, which was then stirred evenly.
  • the slurry was evenly applied to one surface of a 9 ⁇ m-thick aluminum foil using extrusion coating and dried at 90°C to produce a positive electrode sheet with a coating thickness of 100 ⁇ m.
  • the above steps were repeated on the other surface of the positive electrode sheet to obtain a double-sided positive electrode sheet coated with the positive electrode active material layer.
  • the negative electrode sheet was roll-pressed to produce a 79 ⁇ m-thick rolled positive electrode sheet.
  • the positive electrode sheet was cut into sheets measuring 77mm x 735mm for later use.
  • ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were mixed in a mass ratio of 30:50:20, and then lithium hexafluorophosphate ( LiPF6 ) was added to the organic solvent, dissolved and mixed uniformly to obtain an electrolyte, wherein the molar concentration of LiPF6 in the electrolyte was 1.1 mol/L.
  • the prepared positive electrode sheet, separator, and negative electrode sheet are stacked in order, with the separator positioned between the positive and negative electrodes to provide separation.
  • the electrode assembly is then wound to form an electrode assembly.
  • the electrode assembly is then placed in an outer packaging, injected with the prepared electrolyte, and packaged.
  • the lithium-ion battery is then produced through a series of processes including formation, degassing, and trimming.
  • Comparative Examples 1 to 6 and Example 1 The difference between Comparative Examples 1 to 6 and Example 1 is that the type, particle size Dv50, specific surface area, number N' of inorganic ceramic particle groups and inorganic ceramic particles are regulated during the preparation of the negative electrode sheet. The number N of inorganic ceramic particles in the particle group is changed.
  • the control method can refer to Examples 2 to 18. Others are the same as Example 1.
  • the battery was fully discharged and disassembled to obtain the negative electrode.
  • the disassembled electrode was soaked in DMC solvent for 6 hours, then dried in a 60°C oven for 3 hours to remove the solvent, resulting in a dry electrode.
  • a 5 ⁇ m ⁇ 5 ⁇ m section of the negative electrode was cut, ensured to be dry, and fixed to the sample stage.
  • the sample stage and its holder were placed in a CP instrument (IB-09010CP/ion polisher) and adjusted to the appropriate position for cross-section polishing. After cutting, the sample was removed and placed in a SEM-EDS instrument (ZEISS SEM-OXFORD EDS) for scanning electron microscopy analysis.
  • the accelerating voltage was adjusted to 10kV.
  • Example 1 at 3kX magnification the focus, contrast, and brightness were adjusted.
  • the sample was photographed and the number of inorganic ceramic particle groups was determined.
  • the test image of Example 1 at 3kX magnification can be seen in Figure 2.
  • the focus, contrast, and brightness were adjusted at a magnification of 30kX.
  • the sample was photographed and the specific number, specific surface area, and particle size of the individual inorganic ceramic particles were determined.
  • the test chart of Example 1 at 30KX magnification can be seen in FIG3 .
  • the lithium-ion battery is charged and discharged according to the following operating procedures to obtain the discharge capacity of the lithium-ion battery: the lithium-ion battery is charged to 4.45V at a constant current of 0.5C, then charged to 0.025C at a constant voltage of 4.45V, left to stand for 5 minutes, and discharged to 3.0V at a constant current of 0.5C, left to stand for 5 minutes, and the discharge capacity C and discharge platform Vp are obtained.
  • the lithium-ion battery is tested with a laser thickness gauge.
  • Its energy density (ED) C * V p /V, with the unit being Wh/L.
  • Example 1 to 5 when the inorganic ceramic particle material is the same, the Dv50 of the inorganic ceramic particles is 5 nm to 15 nm, the specific surface area of the inorganic ceramic particles is in the range of 60 m 2 /g to 150 m 2 /5 ⁇ N′ ⁇ 15, and the lithium precipitation window is larger, indicating that the battery has better kinetic performance, and at the same time, higher energy density and cycle retention rate.

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  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
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  • General Chemical & Material Sciences (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

一种负极极片、负极极片的制备方法以及二次电池，负极极片包括负极集流体和设置在负极集流体至少一个表面上的负极活性材料层，负极活性材料层包括负极活性材料和无机陶瓷颗粒组，所述无机陶瓷颗粒组中的无机陶瓷颗粒以团簇聚集体形式设置在负极活性材料的表面，对于负极极片，在扫描电镜测试时，在5μm×5μm的范围内，负极活性材料颗粒表面的无机陶瓷颗粒组的数量为N'，3≤N'≤20。二次电池具有较高的能量密度以及较好的动力学性能。

Description

负极极片、负极极片的制备方法以及二次电池 技术领域
本申请涉及电池技术领域，尤其涉及一种负极极片、负极极片的制备方法以及二次电池。
背景技术
二次电池，例如锂离子电池，具有较高的能力密度、较长的循环寿命、较高的充放电效率等优点，已经在世界范围内被广泛使用。
随着二次电池的日益发展，对其能量密度以及动力学性能提出了更高的要求。对于获取高能量密度，现有技术通常采取提高极片的初始压实密度同时增加其涂布重量的方法，而对于获取高动力学，现有技术一般采取降低极片的初始压实密度同时降低涂布重量的方法，可见，现有技术难以兼顾高能量密度与高动力学的锂离子电池。
发明内容
有鉴于此，本申请提供一种负极极片、负极极片的制备方法以及二次电池，能够兼顾提升锂离子电池的能量密度和动力学性能。
第一方面，本申请提供了一种负极极片，负极极片包括负极集流体和设置在负极集流体至少一个表面上的负极活性材料层，负极活性材料层包括负极活性材料和无机陶瓷颗粒组，所述无机陶瓷颗粒组中的无机陶瓷颗粒以团簇聚集体形式设置在负极活性材料的表面(见图1的亮框标注)，对于负极极片，在扫描电镜测试时，在5μm×5μm的范围内，负极活性材料颗粒表面的无机陶瓷颗粒组的数量为N′，3≤N′≤20。本申请通过在负极极片中设置以团簇聚集体 形式附着在负极活性材料表面的多个无机陶瓷颗粒组，同时控制无机陶瓷颗粒组的数量在合适范围，一方面利于提升负极的电位，如此利于提高负极活性材料的容量发挥，进而在不改变活性材料量的情况下提升能量密度(ED)，而且由于负极电位的提升，在充电时更不容易出现析锂(拓宽了析锂窗口)，进而兼顾提升锂离子电池的动力学性能；另一方面，无机陶瓷颗粒是以无机陶瓷颗粒组形式的附着在负极活性材料表面，可避免大量的单颗粒陶瓷分布导致的离子传导受阻，更利于锂离子电池动力学性能的提升。优选地，5≤N′≤15。
在负极浆料的制备过程中，对于不同粒径和比表面积的无机陶瓷颗粒以及其不同的加入量，可以通过调整搅拌时间实现无机陶瓷颗粒组的不同团聚状态，例如，对于Dv50在5nm、W为100m2/g的无机陶瓷颗粒，加入量在0.1％时，搅拌30min可实现N′为1～3，搅拌30min～1h可实现N′为3～10，搅拌1～2h可实现N′为10～20；对于Dv50在15nm、W为60m2/g的无机陶瓷颗粒，加入量在0.1％时，搅拌0min可实现N′为1～3，搅拌10～30min可实现N′为3～10，搅拌30min～1h可实现N′为10～20。总之，对于Dv50越大、W越小、加入量越少的陶瓷，达到同样的N′数量范围，需要的时间越短。以上仅做示例，本申请并不限制。
在一些实施方式中，无机陶瓷颗粒的粒径Dv50为2nm～20nm。在负极极片中引入上述粒径范围的无机陶瓷颗粒，聚集后形成的团簇聚集体更利于提升负极的电位。无机陶瓷颗粒的粒径Dv50过小或者过大(例如小于2nm或大于20nm)均不利于形成合适数量的团簇聚集体。优选地，无机陶瓷颗粒的粒径Dv50为5nm～15nm。
在一些实施方式中，无机陶瓷颗粒的数量为N，N>3。如此，可避免大量的单颗粒陶瓷分布导致的离子传导受阻，其中，团簇聚集体中无机陶瓷颗粒的数量N≤3的均可记为单颗粒陶瓷。优选地，4≤N≤40。
在一些实施方式中，无机陶瓷颗粒的比表面积为W，W>50m2/g。无机陶 瓷颗粒的比表面积在上述范围内，聚集后形成的无机陶瓷颗粒组更利于提升负极的电位，更利于兼顾提升锂离子电池的能量密度和动力学性能。优选地，60m2/g≤W≤150m2/g。
在一些实施方式中，无机陶瓷颗粒选自氟化锂、硫酸锂、钛酸钠、碳酸钙、硫酸钙、磷酸钙、氢氧化铝、氧化铝、硫酸铝、碳酸铝、氢氧化镁、氧化镁、硫酸镁、碳酸镁或氧化硅中的至少一种，基于负极活性材料层的质量，无机陶瓷颗粒组的质量百分含量为0.05wt％至0.3wt％。优选地，无机陶瓷颗粒选自氢氧化铝、二氧化硅、氢氧化镁中的任一种。无机陶瓷颗粒的种类以及含量在上述范围内时，更利于提升锂离子电池的能量密度和动力学性能。
在一些实施方式中，负极极片的厚度为30μm至300μm，负极集流体的厚度为4μm～25μm。
第二方面，本申请提供了一种负极极片的制备方法，包括以下步骤：将负极活性材料、无机陶瓷颗粒、粘结剂和分散剂混合，用去离子水调配成固含量为50％的水系浆料，搅拌0.5h～3h。
在一些实施方式中，分散剂包括有机酸，有机酸的分子量在10w以下，有机酸含有羟基、氨基或亚氨基中的至少一种，有机酸溶于pH在7以上且13以下的水溶液。
在一些实施方式中，负极活性材料、无机陶瓷颗粒、分散剂和粘接剂的质量比为(96～98):(0.1～0.5):(1～2):(1～2)。
第三方面，本申请提供了一种二次电池，二次电池包括上述第一方面的任一种负极极片；或者，二次电池包括上述第二方面的任一种制备方法制备得到的负极极片。
附图说明
为了更清楚地说明本申请实施例或现有技术中的技术方案，下面将对实施 例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为本申请中负极极片的SEM测试图；
图2为本申请中实施例1的负极极片在5μm×5μm的范围内SEM测试图；
图3为图2中负极极片的局部放大SEM测试图。
具体实施方式
为了使本申请的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本申请，并不用于限定本申请。
负极极片
本申请实施例第一方面提供了一种负极极片，负极极片包括负极集流体和设置在负极集流体至少一个表面上的负极活性材料层，负极活性材料层包括负极活性材料和无机陶瓷颗粒组，所述无机陶瓷颗粒组中的无机陶瓷颗粒以团簇聚集体形式设置在负极活性材料的表面，对于负极极片，在扫描电镜测试时，在5μm×5μm的范围内，负极活性材料颗粒表面的无机陶瓷颗粒组的数量为N′，3≤N′≤20。在负极极片中设置以团簇聚集体形式附着在负极活性材料表面的多个无机陶瓷颗粒组，同时控制负极活性材料表面的无机陶瓷颗粒组的数量在上述范围内，一方面可以提高负极的电位，有利于提高负极活性材料的容量发挥，而且由于负极的电位提升，在充电时更不容易出现析锂，利于改善动力学性能；另一方面，无机陶瓷颗粒是以无机陶瓷颗粒组的形式附着在负极活性材料的表面，可避免大量的单颗粒陶瓷(N≤3)分布导致的离子传导受阻，更利于动力学性能的提升，即兼顾提升锂离子电池的能量密度以及动力学性能。
具体地，在一些实施例中，3≤N′≤20。在一些实施例中，4≤N′≤18。在一些实施例中，5≤N′≤15。在一些实施例中，6≤N′≤13。在一些实施例中，8≤N′≤10。示例性地，在扫描电镜测试时，在5μm×5μm的范围内，负极活性材料颗粒表面的无机陶瓷颗粒组的数量N′为3、4、5、6、8、10、12、13、15、18、20或上述任意两个值组成的范围。
在一些实施例中，无机陶瓷颗粒组中无机陶瓷颗粒的粒径Dv50为2nm～20nm。在负极极片中引入上述粒径范围的无机陶瓷颗粒，聚集后更利于形成合适数量的团簇聚集体(N>3)提升负极的电位。示例性地，无机陶瓷颗粒的粒径Dv50为2nm、4nm、5nm、8nm、10nm、12nm、15nm、18nm、20nm或上述任意两个值组成的范围。
在一些实施例中，无机陶瓷颗粒组中无机陶瓷颗粒的数量为N，N>3。无机陶瓷颗粒组中无机陶瓷颗粒的数量在上述范围内，无机陶瓷颗粒组具有合适的二次粒径，更利于提升锂离子电池的动力学性能。具体地，在一些实施例中，N≥6，在一些实施例中，N≥10，在一些实施例中，N≥15，在一些实施例中，N≥20。以上仅为示例，本申请并不限制。优选地，4≤N≤40。
在一些实施例中，无机陶瓷颗粒组中无机陶瓷颗粒的比表面积为W，W>50m2/g。无机陶瓷颗粒的比表面积在上述范围内，聚集后形成的无机陶瓷颗粒组更利于提升负极的电位，兼顾提升锂离子电池的能量密度和动力学性能。具体地，在一些实施例中，55m2/g≤W≤160m2/g。在一些实施例中，60m2/g≤W≤150m2/g。在一些实施例中，65m2/g≤W≤140m2/g。在一些实施例中，85m2/g≤W≤110m2/g。在一些实施例中，90m2/g≤W≤105m2/g。示例性地，无机陶瓷颗粒组中无机陶瓷颗粒的比表面积W为51m2/g、53m2/g、55m2/g、58m2/g、60m2/g、65m2/g、70m2/g、85m2/g、90m2/g、105m2/g、110m2/g、130m2/g、140m2/g、150m2/g、160m2/g或上述任意两个值组成的范围。
在一些实施例中，无机陶瓷颗粒选自氟化锂、硫酸锂、钛酸钠、碳酸钙、 硫酸钙、磷酸钙、氢氧化铝、氧化铝、硫酸铝、碳酸铝、氢氧化镁、氧化镁、硫酸镁、碳酸镁或氧化硅中的至少一种，基于负极活性材料层的质量，无机陶瓷颗粒的质量百分含量为0.05wt％至0.3wt％。无机陶瓷颗粒的质量百分含量在上述范围内时，更利于提升锂离子电池的能量密度和动力学性能。示例性地，无机陶瓷颗粒的质量百分含量为0.05wt％、0.08wt％、0.1wt％、0.15wt％、0.25wt％、0.3wt％或上述任意两个值组成的范围。
在一些实施例中，负极活性材料层的厚度为30μm至300μm。示例性地，负极活性材料层的厚度为30μm、50μm、80μm、100μm、120μm、150μm、180μm、200μm、220μm、250μm、280μm、300μm或上述任意两个值组成的范围。
在一些实施例中，负极集流体的厚度为4μm～25μm。示例性地，负极集流体的厚度为4μm、6μm、8μm、10μm、15μm、20μm、25μm或上述任意两个值组成的范围。
负极极片的制备方法
将负极活性材料、无机陶瓷颗粒、粘结剂和分散剂混合，用去离子水调配成固含量为50％的水系浆料，搅拌0.5h～3h后，采用涂覆方式将得到的浆料涂覆于负极集流体上，涂覆方式优选挤压涂布方式涂覆电极材料，也可以使用凹版、微凹版、电喷涂、转移涂布等方式。极片经过干燥，获得附着力优良、表面光滑的电极材料涂层，以同样的方式涂覆集流体另一面。对于极片干燥，只要是能够使浆料内的溶剂挥发除去的方法就没有特别限定，例如可以列举在大气中50～300℃的温度气氛下进行热处理的方法。干燥方法有自然干燥、暖风干燥、加热干燥、远红外线辐射干燥等，可以使用任一种方法。
负极活性材料为石墨、硅或硅与石墨的混合物，其中，硅为纯硅材料、硅合金材料、硅碳复合材料、硅氧材料的一种或多种混合物。粘结剂包括是SBR(丁苯橡胶)、PAA(聚丙烯酸)、PVA(聚乙烯醇)、聚丙烯酸酯等多种或 一种。分散剂包括有机酸，有机酸的分子量在10w以下，有机酸含有羟基、氨基或亚氨基中的至少一种，有机酸溶于pH在7以上且13以下的水溶液。优选CMC(羧甲基纤维素)作为分散剂。
对于负极集流体，只要是具有电子传导性且在所保持的负极活性物质中可通电的材料就没有特别限定。例如可使用C、Cu、Ni、Fe、V、Nb、Ti、Cr、Mo、Ru、Rh、Ta、W、Os、Ir、Pt、Au、AI等导电性物质、含有这些导电性物质中的两种以上的合金(例如不锈钢)。或为在导电性物质上镀覆不同导电性物质而成的材料(例如在Fe上镀覆Cu而成的材料)。从导电性高、电解液中的稳定性和抗氧化性良好的观点出发，作为集流体，优选Cu、Ni、不锈钢等，进一步从材料成本的观点出发，优选Cu、Ni。负极集流体层的形状没有特别限制，但优选为板状或箔状。对于负极集流体的厚度，优选为4-25μm。
在一些实施例中，负极活性材料、无机陶瓷颗粒、分散剂和粘接剂的质量比为(96～98):(0.1～0.5):(1～2):(1～2)。
二次电池
本申请实施例第二方面提供一种二次电池，二次电池包括正极极片、负极极片、隔离膜和电解液，隔离膜设置在正极极片和负极极片之间，负极极片为上述第一方面的任一种负极极片。
其他
正极极片包括正极集流体以及设置于正极集流体表面的正极活性材料层。本申请对正极集流体没有特别限制，只要能够实现本申请目的即可，例如，可以包含铝箔、铝合金箔或复合集流体(例如聚合物层表面设置金属层的复合集流体)等。本申请对正极集流体的厚度没有特别限制，只要能够实现本申请目的即可。例如，正极集流体的厚度为5μm至13μm。正极活性材料层包括正极活性材料，本申请对正极活性材料没有特别限制，只要能够实现本申请目的即 可，例如，正极活性材料可以包含含有选自由钴、锰、及镍组成的组中的一种或两种以上的与锂的复合金属氧化物、或包含选自铁、钴、镍及锰中的一种或两种以上的含锂的橄榄石型磷酸盐。这些正极活性物质可以单独使用一种或两种以上组合使用。作为这样的锂复合金属氧化物，可适宜列举出例如选自LiCoO2、LiMn2O4、LiNiO2、LiCo1-xNixO2(0.01<x<1)、LiNixMnyCozO2(x+y+z＝1)、Li2MnO3与LiMO2(M为Co、Ni、Mn、Fe等过渡金属)的固溶体、LiNi1/2Mn3/2O4、LiFePO4、LiMnPO4、及LiMn1-xFexPO4(0.01<x<1)中的一种以上，更优选为二种以上。这些与锂的复合金属氧化物或含锂的橄榄石型磷酸盐的一部分可以以其他元素取代，也可以将钴、镍、锰、铁的一部分以选自Co、Mn、Ni、Mg、Al、B、Ti、V、Nb、Cu、Zn、Mo、Ca、Sr、W、及Zr中的一种或两种以上的元素取代、或者以含有这些其他元素的化合物或碳材料被覆。本申请对正极活性材料层的厚度没有特别限制，只要能够实现本申请目的即可。例如，正极活性材料层的厚度为30μm至120μm。正极活性材料层还可以包括导电剂和粘结剂，本申请对导电剂和粘结剂的种类没有特别限制，只要能够实现本申请目的即可。例如，导电剂可以包括但不限于导电炭黑、碳纳米管(CNT)、碳纤维、科琴黑、石墨烯、金属材料或导电聚合物中的至少一种。粘结剂可以包括但不限于聚丙烯酸、聚丙烯酸盐、丙烯酸酯聚合物、聚乙烯醇、聚偏二氟乙烯、聚四氟乙烯或偏二氟乙烯-六氟丙烯共聚物中的至少一种。本申请对正极活性材料层中正极活性材料、导电剂、粘结剂的质量比没有特别限制，本领域技术人员可以根据实际需要选择，只要能够实现本申请目的即可。
隔离膜可以选用任意公知的具有电化学稳定性和化学稳定性的多孔结构隔离膜，例如玻璃纤维、无纺布、聚乙烯(PE)、聚丙烯(PP)及聚偏二氟乙烯(PVDF)中的一种或多种的单层或多层薄膜。
电解液包括有机溶剂、电解质锂盐和添加剂。本发明对其种类不做具体限制，可以根据实际需求进行选择。示例性地，上述有机溶剂包括为碳酸乙烯酯 (EC)、碳酸丙烯酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸丁烯酯(BC)、氟代碳酸乙烯酯(FEC)、甲酸甲酯(MF)、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、1，4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)或二乙砜(ESE)中的一种或多种，优选为两种以上。示例性地，上述电解质锂盐包括LiPF6(六氟磷酸锂)、LiBF4(四氟硼酸锂)、LiClO4(高氯酸锂)、LiAsF6(六氟砷酸锂)、LiFSI(双氟磺酰亚胺锂)、LiTFSI(双三氟甲磺酰亚胺锂)、LiTFS(三氟甲磺酸锂)、LiDFOB(二氟草酸硼酸锂)、LiBOB(二草酸硼酸锂)、LiPO2F2(二氟磷酸锂)、LiDFOP(二氟二草酸磷酸锂)或LiTFOP(四氟草酸磷酸锂)中的一种或多种。上述电解液中还可选地包括其它添加剂，其可以是任意可被用作锂离子二次电池的添加剂，本发明不做具体限制，可以根据实际需求进行选择。作为示例，添加剂可以是碳酸亚乙烯酯(VC)、碳酸乙烯亚乙酯(VEC)、氟代碳酸乙烯酯(FEC)、1,3-丙烷磺酸内酯(PS)、丁二腈(SN)、己二腈(ADN)、1，3-丙烯磺酸内酯(PST)、三(三甲基硅烷)磷酸酯(TMSP)或三(三甲基硅烷)硼酸酯(TMSB)中的一种或多种。
二次电池可以按照本领域常规方法制备。示例性地，将上述正极极片、隔离膜及负极极片按顺序堆叠好，使隔离膜处于正极极片与负极极片之间起到隔离的作用，得到电极组件，也可以是经卷绕后得到电极组件；将电极组件置于包装外壳中，注入电解液并封口，得到二次电池。
对于锂电池的结构没有特别限定，可以适用具有单层或者多层的隔膜的硬币型电池、圆筒型电池、方型电池、或软包电池等。
本申请的锂离子电池的用途没有特别限定，其可用于现有技术中已知的任何电 子装置。
在一些实施例中，本申请的锂离子电池可用于，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
以下，举出实施例及对比例来对本申请的实施方式进行更具体地说明。除非另有声明，所列的份、百分比和比值都是基于重量计。
实施例1
(一)锂离子电池的制备
<负极极片的制备>
将97.4％活性材料人造石墨、0.1％ Al(OH)3、1.3％粘结剂SBR以及1.2％分散剂CMC混合，并用去离子水将混合物料调配成固含量为50％的水系浆料，搅拌1.5h；将制备得到的负极浆料以挤压涂布的方式均匀涂覆于6μm的铜箔上，涂膜后以100℃的温度烘烤干极片，得到涂层厚度为100μm的极片，在该极片的另一个表面上重复以上步骤，得到双面均涂布有负极活性材料层的极片。将负极极片进行辊压，得到厚度为81μm的负极极片。将获得的负极极片裁成78.5mm×732mm的尺寸待用。
实施例2～18与实施例1的区别在于，在负极极片的制备过程中，调控无机陶瓷颗粒的种类、粒径Dv50以及其比表面积的参数，具体见表1，同时，还通过调节水系浆料的搅拌时间用以控制无机陶瓷颗粒组的数量N′和无机陶瓷颗粒组中无机陶瓷颗粒的数量N改变，具体见表1，其他均与实施例1相同。具体 的搅拌时间举例，实施例5中，陶瓷Dv50在15nm、W在100m2/g，搅拌时间在1h，实施例11中，陶瓷Dv50在2nm、W在160m2/g，搅拌时间在3h。
<正极极片的制备>
将正极活性材料钴酸锂(LiCoO2)、导电炭黑(Super P)、粘结剂(PVDF)混合，使得钴酸锂、导电炭黑、粘结剂的重量比为97.5:1.0:1.5，然后加入NMP作为溶剂，调配成固含量为75％的浆料，并搅拌均匀。将浆料以挤压涂布的方式均匀涂布在厚度为9μm的铝箔的一个表面上，90℃条件下烘干，得到涂层厚度为100μm的正极极片，然后在该正极极片的另一个表面上重复以上步骤，得到双面涂布有正极活性材料层的正极极片。将负极极片进行辊压，得到厚度为79μm的辊压后的正极极片。将正极极片裁切成规格为77mm×735mm的片材待用。
<电解液的制备>
在干燥氩气气氛中，将有机溶剂碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)按照质量比30:50:20混合，然后向有机溶剂中加入六氟磷酸锂(LiPF6)溶解并混合均匀，得到电解液，其中，LiPF6在电解液中的摩尔浓度为1.1mol/L。
<锂离子电池的制备>
以厚度为7μm的PE多孔聚合薄膜作为隔离膜，将上述制备的正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正负极中间起到隔离的作用，并卷绕得到电极组件。将电极组件置于外包装中，注入配好的电解液并封装，经过化成，脱气，切边等工艺流程得到锂离子电池。
对比例1～6
对比例1～6与实施例1的区别在于，在负极极片的制备过程中调控无机陶瓷颗粒的种类、粒径Dv50、比表面积、无机陶瓷颗粒组数量N′以及无机陶瓷 颗粒组中无机陶瓷颗粒的数量N改变，调控方法可参见实施例2～18，其他均与实施例1相同。
(二)性能测试
(1)SEM表征无机陶瓷颗粒组
将电池放电完全，拆解得到负极极片，使用DMC溶剂浸泡拆解极片6h后在60℃烘箱中3h烘去溶剂，得到干燥的极片。截取面积为5μm×5μm的负极极片，确保干燥状态并固定在样品台，将样品台连同支架放入CP仪器(IB-09010CP/离子抛光仪)中并调节至合适的位置进行截面抛光处理。切割完成后取出样品并放置在SEM-EDS仪器(ZEISS SEM-OXFORD EDS)中进行扫描电镜分析测试，加速电压调整至10kV，放大至3KX倍数条件下调节焦距、对比度、明亮度，拍照并确定无机陶瓷颗粒组的数量。例如实施例1在3KX倍数下的测试图可参见图2。对于无机陶瓷颗粒组，放大至30KX倍数条件下调节焦距、对比度、明亮度，拍照并确定具体的单颗无机陶瓷颗粒数量、比表面积以及粒径。例如实施例1在30KX倍数下的测试图可参见图3。
(2)电池析锂窗口测试
将电池置于12°恒温箱，静置1h，执行以下测试流程：1)0.7C DC to 3V；2)静置10min；3)XC CC to 4.5V，4.5V CV to 0.05C；4)静置10min；5)1～4步循环10次。调整不同的X(如1.2、1.4、1.6…)并拆解电池，当负极表面无灰白色的析锂时，取X的最大值为析锂窗口。
(3)能量密度测试
在25℃的环境中，将锂离子电池按照下述操作流程充电，再进行放电，得出锂离子电池放电容量：锂离子电池以0.5C恒流充电至4.45V，再以4.45V恒压充电至0.025C，静置5min，以0.5C恒流放电至3.0V，静置5min，得出放电容量C与放电平台Vp。上述锂离子电池充电步骤完成后，用激光测厚仪测试锂 离子电池的长L、宽W、高H，得到锂离子电池的体积V＝L×W×H。其能量密度(ED)＝C*Vp/V，单位为Wh/L。
(4)600圈循环容量保持率测试
在测试温度为25℃的条件下静置30min，接着以1.5C恒流充电至4.3V，恒压充电至1.3C；接着以1.3C恒流充电至4.35V,恒压充电至1.2C，以1.2C恒流充电至4.4V，恒压充电至1.0C；以1.0C恒流充电至4.5V，恒压充电至0.05C；静置5min，以0.7C的电流密度放电至3.0V；静置5min，循环600次。循环第600圈的容量保持率＝(第600圈循环的放电容量/循环第一圈放电容量)×100％。
表1


备注：表1中“/”表示无相关参数，对比例1的负极极片中不含有无机陶瓷颗粒组，其负
极活性材料人造石墨的质量含量97.5％。
结合表1，对比例1和实施例1相比，对比例1的负极极片中不含无机陶瓷颗粒组，其在12℃析锂窗口仅为2.3C，其能量密度为765Wh/L，其在600圈循环容量保持率仅为73％，明显低于实施例1的能量密度780Wh/L以及实施例1的在600圈循环容量保持率90％。
对比例2～6中，对比例2中无机陶瓷颗粒的粒径Dv50过高，导致无机陶瓷颗粒组的数量N′较少且不利于提升负极极片的电位，对比例3中无机陶瓷颗粒的比表面积太小其也不利于形成无机陶瓷颗粒组，对比例4中无机陶瓷颗粒组的数量过多导致离子传导受阻，也不利于提升负极极片的电位，对比例5和对比例6中无机陶瓷颗粒组的数量也不合适。结合表1的数据，对比例2～5对应的锂离子电池的能量密度以及循环性能改善不明显。
实施例1～5和实施例8～11、实施例13～17，在无机陶瓷颗粒材料相同的情况下，无机陶瓷颗粒的Dv50为5nm至15nm，无机陶瓷颗粒比表面积为60m2/g至150m2/5≤N′≤15范围内，析锂窗口更大，说明电池的动力学性能更好，同时能量密度和循环保持率更高。
特别地，进一步调控无机陶瓷颗粒的粒径Dv50以及其比表面积W的范围合适时，能够实现在兼顾拓宽析锂窗口的同时，进一步提升锂离子电池的能量密度和循环性能。
特别地，进一步调整无机陶瓷颗粒组的种类以及含量也合适时，提升锂离子电池的能量密度和循环性能的效果更好。
以上所述仅为本申请的较佳实施例而已，并不用以限制本申请，凡在本申请的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本申请的保护范围之内。

Claims (10)

  1. 一种负极极片，其特征在于，所述负极极片包括负极集流体和设置在所述负极集流体至少一个表面上的负极活性材料层；
    所述负极活性材料层包括负极活性材料和无机陶瓷颗粒组，所述无机陶瓷颗粒组中的无机陶瓷颗粒以团簇聚集体形式设置在所述负极活性材料的表面；
    对于所述负极极片，在扫描电镜测试时，在5μm×5μm的范围内，负极活性材料颗粒表面的无机陶瓷颗粒组的数量为N′，3≤N′≤20。
  2. 根据权利要求1所述的负极极片，其特征在于，所述负极极片满足以下条件中的至少一者：
    (1)所述无机陶瓷颗粒的粒径Dv50为2nm～20nm；
    (2)所述无机陶瓷颗粒的数量为N，N>3；
    (3)所述无机陶瓷颗粒的比表面积为W，W>50m2/g；
    (4)5≤N′≤15。
  3. 根据权利要求2所述的负极极片，其特征在于，所述负极极片满足以下条件中的至少一者：
    (1)所述无机陶瓷颗粒的粒径Dv50为5nm～15nm；
    (2)60m2/g≤W≤150m2/g；
    (3)4≤N≤40。
  4. 根据权利要求1～3任一项所述的负极极片，其特征在于，所述无机陶瓷颗粒选自氟化锂、硫酸锂、钛酸钠、碳酸钙、硫酸钙、磷酸钙、氢氧化铝、氧化铝、硫酸铝、碳酸铝、氢氧化镁、氧化镁、硫酸镁、碳酸镁或氧化硅中的至少一种；
    基于所述负极活性材料层的质量，所述无机陶瓷颗粒的质量百分含量为0.05wt％至0.3wt％。
  5. 根据权利要求4所述的负极极片，其特征在于，所述无机陶瓷颗粒选自氢氧化铝、二氧化硅、氢氧化镁中的任一种。
  6. 根据权利要求1～3任一项所述的负极极片，其特征在于，所述负极极片的厚度为30μm至300μm，所述负极集流体的厚度为4μm～25μm。
  7. 一种负极极片的制备方法，其特征在于，所述制备方法包括以下步骤：
    将负极活性材料、无机陶瓷颗粒、粘结剂和分散剂混合，用去离子水调配成固含量为50％的水系浆料，搅拌0.5h～3h。
  8. 根据权利要求7所述的制备方法，其特征在于，所述分散剂包括有机酸，且满足：
    (1)所述有机酸的分子量在10w以下；
    (2)所述有机酸含有羟基、氨基或亚氨基中的至少一种；
    (2)所述有机酸溶于pH在7以上且13以下的水溶液。
  9. 根据权利要求8所述的制备方法，其特征在于，所述负极活性材料、所述无机陶瓷颗粒、所述分散剂和所述粘接剂的质量比为(96～98):(0.1～0.5):(1～2):(1～2)。
  10. 一种二次电池，其特征在于，所述二次电池包括权利要求1～6任一项所述的负极极片；或者，
    所述二次电池包括由权利要求7～9任一项所述的制备方法制备得到的负极极片。
PCT/CN2024/084168 2024-03-27 2024-03-27 负极极片、负极极片的制备方法以及二次电池 Pending WO2025199815A1 (zh)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020047387A (ja) * 2018-09-14 2020-03-26 トヨタ自動車株式会社 リチウムイオン二次電池用負極
CN110993890A (zh) * 2019-12-16 2020-04-10 东莞维科电池有限公司 一种负极极片、其制备方法和用途
CN115516681A (zh) * 2022-03-01 2022-12-23 宁德新能源科技有限公司 电化学装置及包含该电化学装置的电子装置
CN116960280A (zh) * 2023-09-18 2023-10-27 宁德新能源科技有限公司 负极极片、其制备方法、以及包含其的电化学装置及电子装置
CN117393696A (zh) * 2023-11-01 2024-01-12 宁德新能源科技有限公司 一种负极极片、二次电池和电子装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020047387A (ja) * 2018-09-14 2020-03-26 トヨタ自動車株式会社 リチウムイオン二次電池用負極
CN110993890A (zh) * 2019-12-16 2020-04-10 东莞维科电池有限公司 一种负极极片、其制备方法和用途
CN115516681A (zh) * 2022-03-01 2022-12-23 宁德新能源科技有限公司 电化学装置及包含该电化学装置的电子装置
CN116960280A (zh) * 2023-09-18 2023-10-27 宁德新能源科技有限公司 负极极片、其制备方法、以及包含其的电化学装置及电子装置
CN117393696A (zh) * 2023-11-01 2024-01-12 宁德新能源科技有限公司 一种负极极片、二次电池和电子装置

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