WO2023241104A1 - 电极材料、电极极片及其制备方法、二次电池 - Google Patents

电极材料、电极极片及其制备方法、二次电池 Download PDF

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Publication number
WO2023241104A1
WO2023241104A1 PCT/CN2023/079056 CN2023079056W WO2023241104A1 WO 2023241104 A1 WO2023241104 A1 WO 2023241104A1 CN 2023079056 W CN2023079056 W CN 2023079056W WO 2023241104 A1 WO2023241104 A1 WO 2023241104A1
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Prior art keywords
electrode
binder
active material
lithium
preparation
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PCT/CN2023/079056
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English (en)
French (fr)
Inventor
王正
陆雷
王亚龙
余林真
胡长远
邓凯明
李世松
戴顺浩
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宁德时代新能源科技股份有限公司
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Publication of WO2023241104A1 publication Critical patent/WO2023241104A1/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
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of secondary batteries, and specifically relates to an electrode material, an electrode pole piece and a preparation method thereof, and a secondary battery.
  • Secondary batteries - such as lithium-ion batteries, are mainly composed of positive electrodes, negative electrodes and electrolytes (electrolytes). They are charged and discharged by moving lithium ions between the positive and negative electrodes. Because of their high energy density and high capacity, they can be widely used. Driving power supply for mobile terminals. In recent years, it has also been widely used in electric/hybrid vehicles and other fields.
  • the common industrial manufacturing method of secondary batteries mainly includes using a mixed slurry containing an electrode active material and a binder, and coating it on the electrode current collector by a wet method.
  • organic additives are often added during the preparation process of the electrode pieces, which are difficult to volatilize during drying and easily remain in the electrode pieces, thereby causing risks such as increased interface impedance and segregation.
  • the commonly used binders for positive electrodes are polyvinylidene fluoride (PVDF), and the commonly used binders for negative electrodes are styrene-butadiene rubber (SBR) and/or sodium carboxymethylcellulose (CMC). After coating, they need to be dried and removed in an oven.
  • the solvent in the pole piece requires a large oven footprint (50 to 60 m 2 ) and high energy consumption; and the slurry gel is prone to clogging the filter element due to large viscosity rebound, viscosity fluctuations, and poor filtration, and causes particles due to poor dispersion. Problems such as scratches and fluid thinning; the binder floats and migrates during the drying process, resulting in uneven distribution in the thickness direction, reduced porosity of the upper layer, and rapid cycle attenuation.
  • the purpose of this application is to provide an electrode material, an electrode plate and a preparation method thereof, and a secondary battery.
  • the electrode material has good adhesion and material fusion properties, and can be prepared into an electrode plate using a quasi-dry method, avoiding the need for At present, there are technical problems such as solvent residues in the preparation of electrode plates, large slurry viscosity rebound, easy clogging of the filter element during filtration, uneven dispersion of electrode materials, easy cracking of thick electrode plates, and reduction of secondary battery energy density.
  • a first aspect of the present application provides an electrode material, which includes an electrode active material, a conductive agent, and a binder;
  • the binder includes a first binder, and the first binder Including one or a combination of two or more of the following groups: polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene and perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene and hexafluoropropylene copolymer, ethylene With chlorotrifluoroethylene copolymer;
  • the binder also includes a second binder or a third binder;
  • the second adhesive includes one or a combination of two or more of the following: copolymers of two or more of acrylic acid, acrylate, acrylonitrile, and acrylamide; the first adhesive
  • the mass ratio to the second binder is 0 to 0.2:1;
  • the third binder includes one or a combination of two or more of the following groups: polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene Ethylene terpolymer, fluorine-containing acrylate resin, the mass ratio of the first binder to the third binder is 0.05-0.3:1.
  • the electrode materials have good adhesion and material fusion properties, which avoids the floating of the binders during the preparation process, the easy cracking of thick electrode sheets, and the avoidance of The delamination phenomenon and the risk of demoulding are eliminated, so that thick electrode sheets can be prepared.
  • this electrode material for electrode pole pieces of secondary batteries can increase the proportion of main materials and increase the energy density of the battery core. It also has the advantages of improving lithium ion transmission capacity, reducing impedance, and improving rate performance.
  • the mass percentage of the binder is 0.15-5%.
  • the mass ratio of the first binder to the second binder is 0.01-0.2:1; the mass ratio of the first binder to the third binder is 0.1-0.3: 1.
  • the mass percentage of the electrode active material is 91-99.65%
  • the mass percentage of the conductive agent is 0.2-4%
  • the mass percentage of the binder is 0.15- 5%.
  • the second binder contains a copolymer with a large weight average molecular weight At or equal to 300000.
  • the copolymer contained in the second binder forms a three-dimensional cross-linked network structure through hydrogen bonding between polar groups.
  • the conductive agent includes one or a combination of two or more of the following: conductive carbon black Super P (SP), acetylene black, Ketjen black (KB), carbon fiber, carbon nanotubes (CNTs) ), graphene, conductive graphite (such as KS-6, KS-15, SFG-6, MX-15, etc.).
  • SP conductive carbon black Super P
  • KB Ketjen black
  • CNTs carbon nanotubes
  • graphene such as KS-6, KS-15, SFG-6, MX-15, etc.
  • the electrode material is an electrode material for a positive electrode, which includes a positive active material, a conductive agent, and a binder; the binder includes a first binder and a third binder.
  • the mass percentage of the positive active material is 93-99.65%
  • the mass percentage of the conductive agent is 0.2-4%
  • the mass percentage of the binder is 0.15-3.3%.
  • the mass ratio of the first binder to the third binder is 0.05 ⁇ 0.3:1.
  • the mass percentage of the first binder is 0.1-0.3%, and the mass percentage of the third binder is 0.3-3%.
  • the cathode active material includes one or a combination of two or more of the following group: lithium transition metal oxide, lithium-containing phosphate, Prussian blue, and layered oxide.
  • the lithium transition metal oxide includes one or a combination of two or more selected from the following group: lithium cobalt oxide (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium Manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 /3Co 1 /3Mn 1 /3O 2 , its abbreviation is NCM333; LiNi 0.5 Co 0.2 Mn 0.3 O 2 , its abbreviation is NCM523; LiNi 0.5 Co 0.25 Mn 0.25 O 2 , its abbreviation is NCM211; LiNi 0.6 Co 0.2 Mn 0.2 O 2 , its abbreviation is NCM622; LiNi 0.8 Co 0.1 Mn 0.1 O 2 , which is abbreviated as NCM811), lithium nickel cobalt aluminum oxide (such as
  • the lithium-containing phosphate includes one or a combination of two or more selected from the following group: lithium iron phosphate (such as LiFePO 4 , which is abbreviated as LFP), a composite material of lithium iron phosphate and carbon , lithium manganese phosphate (such as LiMnPO 4 ), composite materials of lithium manganese phosphate and carbon, lithium iron manganese phosphate, composite materials of lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 , which is abbreviated as LFP
  • LiMnPO 4 lithium manganese phosphate
  • the electrode material is an electrode material for a negative electrode, which includes a negative electrode Active material, conductive agent and binder; the binder includes a first binder and a second binder.
  • the mass percentage of the negative active material is 91.7-98.8%
  • the mass percentage of the conductive agent is 0.2-4%
  • the mass percentage of the binder is 1-4.3%.
  • the mass ratio of the first binder to the second binder is 0 to 0.2:1.
  • the mass percentage of the first binder is 0-0.3%, and the mass percentage of the second binder is 1-4%.
  • the negative active material includes one or a combination of two or more selected from the following group: natural graphite, artificial graphite, mesophase microcarbon beads (MCMB), hard carbon, soft carbon, silicon, Silicon-carbon composites.
  • natural graphite artificial graphite
  • mesophase microcarbon beads MCMB
  • hard carbon soft carbon
  • silicon Silicon-carbon composites.
  • a second aspect of the present application provides a battery pole piece, which includes the electrode material described in the first aspect of the present application and a current collector, and the electrode material is disposed on the current collector.
  • the material layer formed of the electrode active material has a porosity of 10% to 45%.
  • the mass per unit area of the electrode material is 150-600 mg/1540.25mm 2 .
  • the electrode pole piece is an electrode pole piece used for a positive electrode, and the mass per unit area of the electrode material on the electrode pole piece is 350 to 600 mg/1540.25mm 2 .
  • the electrode piece is an electrode piece for a positive electrode
  • the electrode active material is a positive active material; wherein the material layer formed by the positive active material has a porosity of 10 to 45%.
  • the electrode piece is an electrode piece used for a negative electrode, and the mass per unit area of the electrode material on the electrode piece is 150 to 400 mg/1540.25 mm 2 .
  • the electrode piece is an electrode piece for a negative electrode
  • the electrode active material is a negative active material; wherein the material layer formed by the negative active material has a porosity of 20 to 45%.
  • the third aspect of this application provides a method for preparing the electrode pole piece described in the second aspect of this application, which includes: mixing the solvent, the electrode active material, the conductive agent and the binder in proportion to obtain an electrode slurry. material; knead the electrode slurry to obtain a lump material; extrusion, Thinning and compounding with the current collector.
  • the preparation method does not include a drying step.
  • the solid content of the electrode slurry is 65% to 90%.
  • an electrode slurry with a high solid content can be used, which not only reduces the manufacturing cost by reducing the amount of solvent used; but also avoids the step of drying to remove the solvent, thereby avoiding the need to dry the solvent.
  • the floating and migration of the binder leads to problems such as uneven distribution in the thickness direction, reduced porosity of the upper layer, and rapid cyclic decay.
  • the preparation method of the electrode slurry includes: mixing the electrode active material, the conductive agent and the first binder in proportion to obtain a powder particle mixture; Mix evenly with the second binder or the third binder and the solvent in proportion to obtain an electrode slurry.
  • the electrode piece is an electrode piece for a positive electrode
  • the electrode active material is a positive active material
  • the preparation method of the electrode slurry includes: combining the positive active material, a conductive agent and After the first binder is mixed uniformly in proportion, a powder particle mixture is obtained; the powder particle mixture, the third binder and the solvent are uniformly mixed in proportion to obtain the electrode slurry.
  • the electrode piece is an electrode piece for a positive electrode
  • the solvent includes one or a combination of two selected from the following group: N-methylpyrrolidone (NMP), small molecule alcohol .
  • the small molecular alcohol is a polyhydric alcohol with a carbon chain length of less than 10; for example, it can be selected from 1,4-butanediol, 1,3-butanediol, and 2,3-butanediol. , one or a combination of two or more of 1,2-propanediol, 1,3-propanediol and 1,3-hexanediol.
  • the electrode piece is an electrode piece used for a positive electrode, and the solid content of the electrode slurry is 70 to 85%.
  • the electrode piece is an electrode piece for a negative electrode
  • the electrode active material is a negative active material
  • the preparation method of the electrode slurry includes: combining the negative active material, a conductive agent and After the first binder is mixed uniformly in proportion, a powder particle mixture is obtained; the powder particle mixture, the second binder and the solvent are uniformly mixed in proportion to obtain the electrode slurry.
  • the electrode piece is an electrode piece for a negative electrode
  • the solvent includes one or a combination of two selected from the following group: deionized water, N-methylpyrrolidone (NMP) , small molecular alcohols, esters.
  • the electrode piece is an electrode piece for a negative electrode
  • the solvent is deionized water
  • the electrode piece is an electrode piece used for a negative electrode, and the solid content of the electrode slurry is 65 to 90%.
  • the preparation method of the electrode slurry includes: mixing the electrode active material, the conductive agent and the first binder in proportion to obtain a powder particle mixture; Mix evenly with the second binder or the third binder and the solvent in proportion to obtain an electrode slurry.
  • the kneading equipment can be a kneader, an internal mixer, a screw extruder, etc.
  • the kneading temperature is 25 to 100°C.
  • the lump material is extruded to prepare thick sheet material
  • the extrusion equipment can be a screw extruder, a hydraulic extruder, etc.
  • the thinning takes the form of rolling.
  • the thinning process parameters include: A/B roller speed ratio 1:1 ⁇ 2; A roller is a mirror roller; B roller is a rough roller with a roughness of 0.2 ⁇ 0.5 ⁇ m; roller pressure 2 ⁇ 30T.
  • the thick sheet material is thinned by one or more rolls and then combined with a current collector to obtain an electrode piece.
  • the compounding takes the form of rolling.
  • the composite process parameters include: the B/C roller speed ratio is 1:1 ⁇ 2; the B roller is a rough roller with a roughness of 0.2 ⁇ 0.5 ⁇ m; the C roller is a rough roller with a roughness of 0.6 ⁇ 0.9 ⁇ m; roller pressure 2 ⁇ 50T.
  • a fourth aspect of the present application provides a secondary battery, which includes the electrode pole piece described in the second aspect of the present application and an electrolyte.
  • the electrode piece is an electrode piece used for a positive electrode, the thickness of the electrode piece is 50-500 ⁇ m, and the compacted density is 2.0-3.8 g/cm 3 ; and/or
  • the electrode pole piece is an electrode pole piece used for a negative electrode, the thickness of the electrode pole piece is 50-500 ⁇ m, and the compacted density is 1.4-1.75g/cm 3 .
  • This application provides an electrode material that uses a specific combination of binders, has good adhesion and material fusion, and avoids delamination and demoulding risks.
  • the electrode material provided by this application is prepared into an electrode plate, there is no need to add additional organic additives such as esters and petroleum ether to avoid solvent residues during processing; and there is no need for drying steps to avoid the need for the binder to Floating migration during the drying process causes problems such as uneven thickness direction and easy cracking of thick pole sheets.
  • This application also provides corresponding electrode plates.
  • thick electrode plates with good uniformity can be prepared, which can be combined into secondary batteries to increase the energy density of the cell; in addition, because the electrode plates
  • the binder content is low, which increases the proportion of main materials and further increases the energy density.
  • This application provides a method for preparing electrode pieces.
  • the preparation method adopts a quasi-dry method to prepare electrode pieces.
  • the electrode slurry has a high solid content and only needs to be kneaded, extruded, thinned, and combined with a current collector.
  • the preparation can be completed by processes such as compounding (for example, using roller pressing); it avoids problems such as large slurry viscosity rebound in wet coating and easy clogging of the filter element during filtration; there is no need to use an oven with a large floor area, effectively reducing energy consumption. Consumption.
  • the secondary battery prepared according to the electrode material provided by this application has good ion transmission capacity, rate performance, and low impedance; in addition, it also has the advantages of low solvent content and low cost, and has good applications. prospect.
  • Figure 1 Battery capacity retention rate of the lithium-ion battery provided by some embodiments of the present application during multiple charge and discharge cycles at 25°C.
  • Ranges disclosed in this application are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the edges of the particular range. boundary. Ranges defined in this manner are inclusive of the endpoints and may be combined arbitrarily, that is, any lower limit may be combined with any upper limit to form a range.
  • steps of the present application can be performed sequentially or randomly, and are preferably performed sequentially.
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • an electrode material which includes an electrode active material, a conductive agent and a binder;
  • the binder includes a first binder, and the first binder includes the following One or a combination of two or more in the group: polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene and perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene and hexafluoropropylene copolymer, ethylene and trifluoroethylene Chlorofluoroethylene copolymer;
  • the binder also includes a second binder or a third binder;
  • the second adhesive includes one or a combination of two or more of the following: copolymers of two or more of acrylic acid, acrylate, acrylonitrile, and acrylamide; the first adhesive
  • the mass ratio to the second binder is 0 to 0.2:1;
  • the third binder includes one or a combination of two or more of the following groups: polyvinylidene fluoride, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene Ethylene terpolymer, fluorine-containing acrylate resin (such as trifluoroethyl acrylate homopolymer, trifluoroethyl methacrylate homopolymer, pentafluoropropyl acrylate homopolymer, etc.), the first bonding
  • the mass ratio of the agent to the third binder is 0.05-0.3:1.
  • the electrode material has good adhesion and material fusion, and avoids the floating and thickening of the binder during the preparation process.
  • the pole piece is easy to crack, which avoids the delamination phenomenon and the risk of demolding, so that thick pole pieces can be prepared.
  • Using this electrode material for electrode pole pieces of secondary batteries can increase the proportion of main materials and increase the energy density of the battery core. It also has the advantages of improving lithium ion transmission capacity, reducing impedance, and improving rate performance.
  • the mass ratio of the first binder to the second binder is 0 to 0.2:1; for example, in some embodiments, the first binder does not exist; in other embodiments In the way, The mass ratio of the first binder to the second binder can be selected from 0.01:1, 0.02:1, 0.05:1, 0.1:1, 0.15:1, 0.2:1, etc.
  • first binder and the second binder at the same time is more conducive to improving the wettability of the electrode piece prepared from the electrode material to the electrolyte than using only the second binder in a reasonable ratio.
  • the mass ratio of the first binder to the third binder is 0.05-0.3:1, for example, it can be selected from 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25:1 , 0.3:1, etc.
  • this application effectively improves the adhesion, material fusion, etc. of the electrode material; such as It is not within the range of the ratio.
  • increasing the content of the first-added binder will reduce the material fusion, the adhesion between the diaphragm and the current collector, and increase the risk of defilming during the cycle.
  • Increasing the second/third-added binder will The content will increase the viscosity of the material, causing the sticky roller to be unable to complete the transfer and compounding of the current collector; reducing the content of the first-added binder will reduce the strength of the diaphragm, and reducing the content of the second/third-added binder will cause the film to Chip adhesion is reduced.
  • the mass percentage of the binder in the electrode material is 0.15-5%, for example, it can be selected from 0.15%, 0.5%, 1%, 1.1%, 1.15%, 1.25%, 1.3%, 2 %, 2.7%, 3%, 3.5%, 4%, 4.5%, 5%, etc.
  • the mass percentage of the binder is less than 0.15%, the lump material cannot be prepared, and it is not enough to provide sufficient bonding force; if the mass percentage is higher than 5%, the viscosity of the material is high, and during the thinning process It is easy to stick to the roller and it is impossible to transfer the film.
  • the mass percentage of the electrode active material is 91 to 99.65%, such as 91%, 91.5%, 92%, 92.5%, 93%, 93.5%, 94%, 94.5%, 95%, 95.5%, 96%, 96.5%, 97 %, 97.5%, 98%, 98.5%, 99%, 99.65%, etc.; the mass percentage of conductive agent is 0.2 ⁇ 4%, such as 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3% , 3.5%, 4%, etc.
  • the conductive agent exceeds the upper limit, the content of the active main material will decrease, and the energy density of the cell will decrease; if the conductive agent exceeds the lower limit, the conductivity of the pole piece will be insufficient, causing the cell impedance to increase and the rate performance to decrease.
  • the copolymer contained in the second binder has a weight average molecular weight greater than or equal to 300,000; the copolymer contained in the second binder is formed through hydrogen bonding between polar groups. Three-dimensional cross-linked network structure.
  • the conductive agent in the electrode material includes one or a combination of two or more of the following groups: conductive carbon black Super P (SP), acetylene black, Ketjen black (KB), carbon fiber, carbon nanotubes (CNTs), graphene, conductive graphite (such as KS-6, KS-15, SFG-6, MX-15, etc.).
  • SP conductive carbon black Super P
  • KB Ketjen black
  • CNTs carbon nanotubes
  • graphene such as KS-6, KS-15, SFG-6, MX-15, etc.
  • the electrode material is a cathode material, which includes a cathode active material, a conductive agent and a binder; the binder includes a first binder and a third binder; wherein, the mass percentage of the cathode active material 93 ⁇ 99.65%, such as 93%, 93.5%, 94%, 94.5%, 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, 99.65%, etc.;
  • the mass percentage of the conductive agent is 0.2 ⁇ 4%, such as 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, etc.; the mass percentage of the binder is 0.15 ⁇ 3.3%, such as 0.15%, 0.5%, 1%, 1.1%, 1.15%, 1.25%, 1.3%, 2%, 2.7%, 3%, 3.3%, etc.
  • the mass percentage of each raw material mentioned above is obtained after optimizing the cathode material
  • the mass ratio of the first binder to the third binder in the cathode material is 0.05-0.3:1; for example, 0.05:1, 0.1:1, 0.15:1, 0.2:1, 0.25 :1, 0.3:1, etc.
  • the mass percentage of the first binder in the cathode material is 0.1 to 0.3%, such as 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, etc.; the mass percentage of the third binder The percentage is 0.3 to 3%, such as 0.3%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, etc.
  • the cathode active material includes lithium transition metal oxides, such as lithium cobalt oxide (eg, LiCoO 2 ), lithium nickel oxide (eg, LiNiO 2 ), lithium manganese oxide (eg, LiMnO 2 , LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 /3Co 1 /3Mn 1 /3O 2 , its abbreviation is NCM333; LiNi 0.5 Co 0.2 Mn 0.3 O 2 , its abbreviation is NCM523; LiNi 0.5 Co 0.25 Mn 0.25 O 2 , its abbreviation is NCM211; LiNi 0.6 Co 0.2 Mn 0.2 O 2 , its abbreviation is NCM622; LiNi 0.8 Co 0.1 Mn 0.1 O 2 , its abbreviation is NCM811 ), lithium nickel cobalt aluminum oxide (such as LiCoO
  • the positive active material includes lithium-containing phosphates, such as lithium iron phosphate (such as LiFePO 4 , which is abbreviated as LFP), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), manganese phosphate Composite materials of lithium and carbon, lithium iron manganese phosphate, composite materials of lithium iron manganese phosphate and carbon, etc.
  • lithium iron phosphate such as LiFePO 4 , which is abbreviated as LFP
  • composite materials of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate Composite materials of lithium and carbon
  • LiMnPO 4 lithium manganese phosphate Composite materials of lithium and carbon, lithium iron manganese phosphate, composite materials of lithium iron manganese phosphate and carbon, etc.
  • the positive active material includes Prussian blue.
  • the cathode active material includes layered oxide.
  • the electrode material is a negative electrode material, which includes a negative active material, a conductive agent, and a binder; the binder includes a first binder and a second binder; wherein, the mass of the negative active material
  • the percentage is 91.7 ⁇ 98.8%, such as 91.7%, 92%, 92.5%, 93%, 93.5%, 94%, 94.5%, 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.8%, etc.
  • the mass percentage of conductive agent is 0.2 ⁇ 4%, such as 0.2%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, etc.
  • the quality of the binder The percentage is 1 to 4.3%, such as 1%, 1.5%, 2%, 2.5%, 2.7%, 3%, 3.5%, 4%, 4.3%, etc.
  • the mass percentage of each raw material mentioned above is obtained after optimizing the negative electrode material.
  • the binder of the negative electrode material includes the second binder and does not include the first binder.
  • the mass ratio of the first binder to the second binder in the negative electrode material is 0.01 to 0.2:1; for example, 0.01:1, 0.02:1, 0.05:1, 0.1:1, 0.15 :1, 0.2:1, etc.
  • the mass percentage of the first binder in the negative electrode material is 0.05-0.3%, such as 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, etc.; the second binder The mass percentage of the agent is 1 to 4%, such as 1%, 1.2%, 1.5%, 1.7%, 1.8%, 1.9%, 1.95%, 2%, 3%, 4%, etc.
  • the negative active material includes one or a combination of two or more selected from the following group: natural graphite, artificial graphite, mesophase microcarbon beads (MCMB), hard carbon, soft carbon, silicon, silicon- Carbon composite.
  • MCMB mesophase microcarbon beads
  • a battery pole piece which includes a current collector, and an electrode material provided in the present application disposed on the current collector; wherein the material layer formed by the electrode active material has a porosity of 10 ⁇ 45%, such as 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, etc.
  • This porosity is conducive to increasing the electrolyte infiltration rate, reducing the standing time after liquid injection, improving production efficiency and reducing costs, while improving the diffusion capacity of lithium ions in the pole pieces, reducing impedance, and improving the rate performance of the battery core; such as porosity If it is not within the above range, the energy density of the battery core will be reduced, and the rate and high and low temperature performance will be reduced.
  • the unit area mass of the electrode material on the electrode pole piece is 150 ⁇ 600mg/1540.25mm 2 , for example about 150mg/1540.25mm 2 , 197mg/1540.25mm 2 , 200mg/1540.25mm 2 , 250mg/1540.25mm 2 , 300mg/1540.25mm 2 , 400mg/1540.25mm 2 , 430mg/1540.25mm 2 , 450mg/1540.25mm 2 , 480mg/1540.25mm 2 , 500mg/1540.25mm 2 , 550mg/1540.25mm 2 , 600mg/1540.25mm 2 , etc.
  • the electrode piece is a positive electrode piece
  • the material layer formed of the electrode active material has a porosity of 10-45%
  • the unit area mass of the electrode material on the electrode piece is 350-600mg/1540.25mm 2 .
  • the electrode piece is a negative electrode piece, and the material layer formed of the electrode active material has a porosity of 20 to 45%; the mass per unit area of the electrode material on the electrode piece is 150 to 400 mg/1540.25 mm2 .
  • a method for preparing the above-mentioned electrode pole piece includes: mixing the solvent, the electrode active material, the conductive agent and the binder uniformly in proportion to obtain an electrode slurry; Knead to obtain a dough-like material; the dough-like material is extruded, thinned, and compounded with the current collector in sequence.
  • the preparation method does not include a drying step; preferably, the solid content of the electrode slurry is 65% to 90%, such as 65%, 70%, 75%, 80%, 85%, 90% etc.
  • the amount of solvent used can be significantly reduced when preparing the electrode pole piece, thus avoiding the need for drying to remove the solvent. , thus avoiding problems such as uneven distribution in the thickness direction, lower porosity of the upper layer, and rapid cycle attenuation caused by floating migration of the binder during the upward evaporation process of the dry solvent.
  • a kneader, internal mixer or screw extruder is used as the kneading equipment, and the kneading temperature is 25-100°C; a screw extruder or a hydraulic extruder is used for extrusion, and the lump material is extruded.
  • Thick sheet material is produced; then the thick sheet material is thinned by rolling.
  • the thinning process is preferably A/B roller speed ratio 1:1 ⁇ 2; A roller is a mirror roller; B roller is a rough roller, rough The thickness is 0.2 ⁇ 0.5 ⁇ m; the roller pressure is 2 ⁇ 30T; and then the thick sheet material is compounded with the current collector after being thinned.
  • the compounding method is roller pressing, and the process is preferably B/C roller speed ratio 1:1 ⁇ 2 ;
  • Roller B is a rough roller with a roughness of 0.2 ⁇ 0.5 ⁇ m;
  • roller C is a rough roller with a roughness of 0.6 ⁇ 0.9 ⁇ m;
  • roller pressure is 2 ⁇ 50T.
  • a method for preparing a positive electrode sheet including: combining a positive active material, After the conductive agent and the first binder are mixed uniformly in proportion, a powder particle mixture is obtained; the powder particle mixture is mixed uniformly with the third binder and the solvent in proportion to obtain the electrode slurry; Preferably, the solid content of the electrode slurry is 70-85%.
  • the solvent includes one or a combination of two selected from the following group: N-methylpyrrolidone (NMP), small molecular alcohol (polyol with a carbon chain length of less than 10; for example Can be selected from one of 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-propanediol, 1,3-propanediol and 1,3-hexanediol or a combination of two or more).
  • NMP N-methylpyrrolidone
  • polyol with a carbon chain length of less than 10 for example Can be selected from one of 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-propanediol, 1,3-propanediol and 1,3-hexanediol or a combination of two or more).
  • a method for preparing a negative electrode sheet including: mixing the negative active material, the conductive agent and the first binder in proportion to obtain a powder particle mixture; Mix evenly with the second binder and the solvent in proportion to obtain the electrode slurry.
  • the solid content of the electrode slurry is 65 to 90%.
  • the solvent includes one or a combination of two selected from the following group: deionized water, N-methylpyrrolidone (NMP), small molecular alcohol (carbon chain length is less than 10 Polyol; for example, it can be selected from 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-propanediol, 1,3-propanediol, 1,3-hexanediol One or a combination of two or more), ester; preferably deionized water.
  • NMP N-methylpyrrolidone
  • small molecular alcohol carbon chain length is less than 10 Polyol; for example, it can be selected from 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-propanediol, 1,3-propanediol, 1,3-hexanediol
  • ester preferably
  • a secondary battery which includes the electrode plate provided by the application and an electrolyte; the positive electrode plate of the secondary battery is the electrode plate provided by the application, and the negative electrode plate is a conventional commercially available electrode. or the negative electrode piece of the secondary battery is the electrode piece provided by this application, and the positive electrode piece is a conventional commercially available electrode piece; preferably, the positive electrode piece and the negative electrode piece of the secondary battery are both provided by this application Electrode pole piece.
  • the secondary battery provided by this application has the advantages of high energy density, small cell impedance, high rate performance and cycle performance.
  • the thickness of the positive electrode sheet in the secondary battery is 50-500 ⁇ m, and the compacted density is 2.0-3.8 g/cm 3 ; the thickness of the negative electrode sheet is 50-500 ⁇ m, and the compacted density is 1.4-1.75 g/cm 3 .
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the mass per unit area of the electrode material is 400mg/1540.25mm 2 .
  • the above-mentioned positive electrode piece, a 14 ⁇ m thick polyethylene film as a separator, and the above-mentioned negative electrode piece are laminated in sequence, so that the separator is between the positive electrode piece and the negative electrode piece to play an isolation role, and the bare electrode is obtained by winding core.
  • the bare battery core is placed in the outer packaging, dried and then injected with electrolyte, and then goes through processes such as vacuum packaging, standing, formation, and shaping to prepare a lithium-ion battery.
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the positive electrode sheet in step (1) in Example 1 is the same: the mass ratio of lithium iron phosphate, conductive carbon black Super P, polytetrafluoroethylene and polyvinylidene fluoride is 98.2:0.7:0.1 :1.
  • step (3) Same as step (3) in step (3) of the secondary battery preparation method in Example 1.
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the positive electrode sheet in step (1) in Example 1 is the same: the mass ratio of lithium iron phosphate, conductive carbon black Super P, polytetrafluoroethylene and polyvinylidene fluoride is 98.2:0.7:0.15 :1.
  • the secondary battery was prepared in the same manner as step (3) in Example 2.
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the positive electrode sheet in step (1) in Example 1 is the same: the mass ratio of lithium iron phosphate, conductive carbon black Super P, polytetrafluoroethylene and polyvinylidene fluoride is 98.05:0.7:0.25 :1.
  • the secondary battery was prepared in the same manner as step (3) in Example 2.
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the positive electrode sheet in step (1) of Example 1 is the same: the mass ratio of lithium iron phosphate, conductive carbon black Super P, polytetrafluoroethylene and polyvinylidene fluoride is 98:0.7:0.3 :1.
  • the secondary battery was prepared in the same manner as step (3) in Example 2.
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the secondary battery was prepared in the same manner as step (3) in Example 2.
  • a lithium ion battery is provided.
  • the preparation method is the same except that the negative electrode plate is prepared according to the following steps.
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the negative electrode sheet in step (2) in Example 7 artificial The mass ratio of graphite, conductive carbon black Super P, polytetrafluoroethylene, and acrylic acid-acrylamide-acrylonitrile copolymer is 97.3:0.7:0.1:1.9.
  • the secondary battery was prepared in the same manner as step (3) in Example 6.
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the negative electrode sheet in step (2) in Example 7 is the same: the mass ratio of artificial graphite, conductive carbon black Super P, polytetrafluoroethylene, acrylic acid-acrylamide-acrylonitrile copolymer is 97.3 :0.7:0.2:1.8.
  • the secondary battery was prepared in the same manner as step (3) in Example 6.
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the negative electrode sheet in step (2) in Example 7 is the same: the mass ratio of artificial graphite, conductive carbon black Super P, polytetrafluoroethylene, acrylic acid-acrylamide-acrylonitrile copolymer is 97.3 :0.7:0.3:1.7.
  • the secondary battery was prepared in the same manner as step (3) in Example 6.
  • a lithium ion battery is provided.
  • the preparation method of the positive electrode sheet and the secondary battery is the same as that in Example 1, and the preparation method of the negative electrode sheet is the same as that in Example 9.
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the positive electrode sheet is the same as step (1) in Example 1: the mass per unit area of the electrode material is 430 mg/1540.25mm 2 .
  • the preparation method of the negative electrode piece in step (2) in Example 9 is the same: the mass per unit area of the electrode material is 212 mg/1540.25mm 2 .
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the positive electrode sheet is the same as step (1) in Example 1: the mass per unit area of the electrode material is 450 mg/1540.25mm 2 .
  • the preparation method of the negative electrode piece in step (2) in Example 9 is the same: the mass per unit area of the electrode material is 222 mg/1540.25mm 2 .
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the positive electrode sheet is the same as step (1) in Example 1: the mass per unit area of the electrode material is 480 mg/1540.25mm 2 .
  • the preparation method of the negative electrode piece in step (2) in Example 9 is the same: the mass per unit area of the electrode material is 237 mg/1540.25 mm 2 .
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the positive electrode sheet in step (1) of Example 6 is the same: the mass per unit area of the electrode material is 400 mg/1540.25mm 2 .
  • the preparation method of the negative electrode piece in step (2) in Example 1 is the same: the mass per unit area of the electrode material is 197 mg/1540.25 mm 2 .
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the positive electrode sheet in step (1) of Example 6 is the same: the mass per unit area of the electrode material is 430 mg/1540.25mm 2 .
  • the preparation method of the negative electrode piece in step (2) in Example 1 is the same: the mass per unit area of the electrode material is 212 mg/1540.25mm 2 .
  • a lithium-ion battery is provided, and its preparation method is as follows:
  • the preparation method of the positive electrode sheet in step (1) in Example 6 is the same: the mass per unit area of the electrode material is 450 mg/1540.25mm 2 .
  • the preparation method of the negative electrode sheet is the same as step (2) in Example 1: the mass per unit area of the electrode material is 222 mg/1540.25mm 2 .
  • the lithium-ion batteries prepared in the examples and comparative examples were tested, as follows:
  • Test method Use a capillary tube (diameter 1mm) to absorb a certain amount of electrolyte (height 2cm), so that the suction end of the capillary tube is in contact with the surface of the electrode plate.
  • the electrode piece has a porous structure. Under capillary force, the electrolyte in the capillary can be sucked out. The time required for the electrolyte to be completely absorbed is recorded, and the electrolyte infiltration rate is calculated.
  • Rate discharge charge at 0.33C to 3.65V constant voltage, charge until the current is 0.05C, let it sit for 5 minutes, discharge at 0.33C to 2.5V and measure the discharge capacity during the period, let it stand for 30 minutes; charge at 0.33C to 3.65V at constant voltage.
  • Rate charging charge at 0.33C to 3.65V constant voltage, charge until the current is 0.05C, let it sit for 5 minutes, discharge at 0.33C to 2.5V, and measure the charging capacity during the period, let it stand for 30 minutes; charge at 1C to 3.65V at constant voltage.
  • a charge-discharge cycle process is as follows: charge with a constant current of 1C to 3.65V, then charge with a constant voltage of 3.65V to a current of 0.05C, let it stand for 5 minutes, and then discharge with a constant current of 1C to 2.5V. Record the battery capacity at this time as C1, the above is a charge and discharge cycle of the battery, cycle according to the above process.
  • the capacity retention rate of lithium-ion batteries during cycling is shown in Figure 1.
  • V2 S*H*A, where: S-area, cm 2 ; H-thickness, cm; A-number of samples, EA;
  • the test results of pole piece porosity are shown in Table 4.

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Abstract

本申请提供了一种电极材料、电极极片及其制备方法、二次电池，该电极材料包括电极活性材料、导电剂和粘结剂；其中，粘结剂包括第一粘结剂和第二粘结剂(质量比0～0.2：1)，或者第一粘结剂和第三粘结剂(质量比0.05～0.3：1)；第一粘结剂包括聚四氟乙烯、聚三氟氯乙烯、四氟乙烯-全氟烷基乙烯基醚共聚物、四氟乙烯-六氟丙烯共聚物、乙烯-三氟氯乙烯共聚物中的一种或几种；第二粘结剂包括丙烯酸、丙烯酸酯、丙烯腈、丙烯酰胺中的两种或两种以上的共聚物；第三粘结剂包括聚偏氟乙烯、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、含氟丙烯酸酯树脂中的一种或几种。

Description

电极材料、电极极片及其制备方法、二次电池
相关申请的交叉引用
本申请要求享有于2022年6月14日提交的名称为“电极材料、电极极片及其制备方法、二次电池”的中国专利申请202210667718.0的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及二次电池技术领域，具体涉及一种电极材料、电极极片及其制备方法、二次电池。
背景技术
二次电池——例如锂离子电池，主要由正极、负极和电解质(电解液)构成，通过锂离子在正负极之间移动而进行充放电，因其具有高能量密度及高容量，可广泛应用于移动终端的驱动电源。近年来，亦广泛应用在电动/混合动力汽车等领域。
目前，二次电池的通常工业制造方法，主要包括使用含有电极活性物质和粘合剂的混合浆料，通过湿法涂布于电极集流体上。并且，现有技术中常在电极极片制备过程中加入有机助剂，其在烘干中挥发困难，易残留在电极极片中，从而造成界面阻抗增加、析理等风险。
正极常用的粘结剂为聚偏氟乙烯(PVDF)，负极常用的粘结剂为丁苯橡胶(SBR)和/或羧甲基纤维素钠(CMC)，涂布后需要烘箱进行烘干去除极片中溶剂，烘箱的占地面积较大(需50～60m2)、能耗大；且浆料凝胶易由于粘度反弹大、粘度波动、过滤不良从而堵塞滤芯，由于分散不良从而导致颗粒划痕、流体削薄等问题；粘结剂在干燥过程中上浮迁移，从而导致厚度方向分布不均、上层孔隙率降低，循环衰减快等问题。
发明内容
本申请的目的在于提供一种电极材料、电极极片及其制备方法、二次电池，该电极材料具有良好的粘合性和物料融合性，可采用准干法制备为电极极片，避免了目前电极极片制备中溶剂残留、浆料粘度反弹大、易在过滤时堵塞滤芯、电极材料分散不均匀、制备厚极片易开裂、降低二次电池能量密度等技术问题。
为此，本申请的第一方面提供一种电极材料，所述电极材料包括电极活性材料、导电剂和粘结剂；所述粘结剂包括第一粘结剂，所述第一粘结剂包括下组中的一种或两种以上的组合：聚四氟乙烯、聚三氟氯乙烯、四氟乙烯与全氟烷基乙烯基醚共聚物、四氟乙烯与六氟丙烯共聚物、乙烯与三氟氯乙烯共聚物；所述粘结剂还包括第二粘结剂或第三粘结剂；
所述第二粘结剂包括下组中的一种或两种以上的组合：丙烯酸、丙烯酸酯、丙烯腈、丙烯酰胺中的两种或两种以上的共聚物；所述第一粘结剂与所述第二粘结剂的质量比为0～0.2：1；
所述第三粘结剂包括下组中的一种或两种以上的组合：聚偏氟乙烯、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、含氟丙烯酸酯树脂，所述第一粘结剂与所述第三粘结剂的质量比为0.05～0.3：1。
由此，本申请通过应用上述电极材料特别是其中的粘结剂，使得该电极材料具有良好的粘合性和物料融合性，避免了制备过程中粘结剂上浮、厚极片易开裂，避免了分层现象及脱模风险，从而可以制备得到厚极片。将该电极材料用于二次电池的电极极片，可提高主材占比、增大电芯能量密度，并且具有提高锂离子传输能力、降低阻抗、提高倍率性能的优点。
在任意实施方式中，所述电极材料中，所述粘结剂的质量百分比为0.15～5％。
在任意实施方式中，所述第一粘结剂与第二粘结剂的质量比为0.01～0.2：1；所述第一粘结剂与第三粘结剂的质量比为0.1～0.3：1。
在任意实施方式中，所述电极材料中，所述电极活性材料的质量百分比为91～99.65％，所述导电剂的质量百分比为0.2～4％，所述粘结剂的质量百分比为0.15-5％。
在任意实施方式中，所述第二粘结剂所包含的共聚物，其重均分子量大 于或等于300000。
在任意实施方式中，所述第二粘结剂所包含的共聚物中，通过极性基团之间的氢键作用形成三维交联网状结构。
在任意实施方式中，所述导电剂包括下组中的一种或两种以上的组合：导电炭黑Super P(SP)、乙炔黑、科琴黑(KB)、碳纤维、碳纳米管(CNTs)、石墨烯、导电石墨(例如KS-6、KS-15、SFG-6、MX-15等)。
在任意实施方式中，所述电极材料为用于正极的电极材料，其包括正极活性材料、导电剂和粘结剂；所述粘结剂包括第一粘结剂和第三粘结剂。
在任意实施方式中，所述电极材料中，所述正极活性材料的质量百分比为93～99.65％，导电剂的质量百分比为0.2～4％，粘结剂的质量百分比为0.15～3.3％。
在任意实施方式中，所述电极材料中，所述第一粘结剂与所述第三粘结剂的质量比为0.05～0.3:1。
在任意实施方式中，所述电极材料中，所述第一粘结剂的质量百分比为0.1～0.3％，所述第三粘结剂的质量百分比为0.3～3％。
在任意实施方式中，所述正极活性材料包括下组中的一种或两种以上的组合：锂过渡金属氧化物、含锂磷酸盐、普鲁士蓝、层状氧化物。
在任意实施方式中，所述锂过渡金属氧化物包括选自下组中的一种或两种以上的组合：锂钴氧化物(例如LiCoO2)、锂镍氧化物(例如LiNiO2)、锂锰氧化物(例如LiMnO2、LiMn2O4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(例如LiNi1/3Co1/3Mn1/3O2，其简称为NCM333；LiNi0.5Co0.2Mn0.3O2，其简称为NCM523；LiNi0.5Co0.25Mn0.25O2，其简称为NCM211；LiNi0.6Co0.2Mn0.2O2，其简称为NCM622；LiNi0.8Co0.1Mn0.1O2，其简称为NCM811)、锂镍钴铝氧化物(例如LiNi0.85Co0.15Al0.05O2)及其改性化合物。
在任意实施方式中，所述含锂磷酸盐包括选自下组中的一种或两种以上的组合：磷酸铁锂(例如LiFePO4，其简称为LFP)、磷酸铁锂与碳的复合材料、磷酸锰锂(例如LiMnPO4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料。
在任意实施方式中，所述电极材料为用于负极的电极材料，其包括负极 活性材料、导电剂和粘结剂；所述粘结剂包括第一粘结剂和第二粘结剂。
在任意实施方式中，所述电极材料中，所述负极活性材料的质量百分比为91.7～98.8％，导电剂的质量百分比为0.2～4％，粘结剂的质量百分比为1～4.3％。
在任意实施方式中，所述电极材料中，所述第一粘结剂与所述第二粘结剂的质量比为0～0.2：1。
在任意实施方式中，所述电极材料中，所述第一粘结剂的质量百分比为0～0.3％，所述第二粘结剂的质量百分比为1～4％。
在任意实施方式中，所述负极活性材料包括选自下组中的一种或两种以上的组合：天然石墨、人造石墨、中间相微碳球(MCMB)、硬碳、软碳、硅、硅-碳复合物。
本申请的第二方面，提供一种电池极片，其包括本申请第一方面所述的电极材料和集流体，所述电极材料设置于所述集流体上。
在任意实施方式中，在所述电极极片上，所述电极活性材料形成的物质层的孔隙率为10～45％。
在任意实施方式中，在所述电极极片上，所述电极材料的单位面积质量为150～600mg/1540.25mm2。
在任意实施方式中，所述电极极片为用于正极的电极极片，在所述电极极片上，所述电极材料的单位面积质量为350～600mg/1540.25mm2。
在任意实施方式中，所述电极极片为用于正极的电极极片，所述电极活性材料为正极活性材料；其中，所述正极活性材料形成的物质层的孔隙率为10～45％。
在任意实施方式中，所述电极极片为用于负极的电极极片，在所述电极极片上，所述电极材料的单位面积质量为150～400mg/1540.25mm2。
在任意实施方式中，所述电极极片为用于负极的电极极片，所述电极活性材料为负极活性材料；其中，所述负极活性材料形成的物质层的孔隙率为20～45％。
本申请的第三方面，提供本申请第二方面所述的电极极片的制备方法，其包括：将溶剂、所述电极活性材料、导电剂和粘结剂按比例混合均匀后，得到电极浆料；将所述电极浆料捏合得到团状物料；将所述团状物料依次经挤出、 减薄、与所述集流体复合。
在任意实施方式中，所述制备方法中，不包括烘干步骤。
在任意实施方式中，所述电极浆料的固含量为65～90％。
根据本申请的实施例，可采用高固含量的电极浆料，通过降低溶剂的使用量，不仅降低了制造成本；而且避免了需要用烘干来去除溶剂的步骤，从而避免了在干燥溶剂向上挥发过程中粘结剂上浮迁移导致厚度方向分布不均、上层孔隙率降低、循环衰减快等问题。
在任意实施方式中，所述电极浆料的制备方法包括：将所述电极活性材料、导电剂和第一粘结剂按比例混合均匀后，得到粉体颗粒混合物；将所述粉体颗粒混合物与所述第二粘结剂或者所述第三粘结剂、所述溶剂按比例混合均匀，得到电极浆料。
在任意实施方式中，所述电极极片为用于正极的电极极片，所述电极活性材料为正极活性材料；所述电极浆料的制备方法包括：将所述正极活性材料、导电剂和第一粘结剂按比例混合均匀后，得到粉体颗粒混合物；将所述粉体颗粒混合物与所述第三粘结剂、所述溶剂按比例混合均匀，得到所述电极浆料。
在任意实施方式中，所述电极极片为用于正极的电极极片，所述溶剂包括选自下组中的一种或两种的组合：N-甲基吡咯烷酮(NMP)、小分子醇。
根据本申请的实施例，所述小分子醇为碳链长度为10以下的多元醇；例如可选自1，4-丁二醇、1，3-丁二醇、2，3-丁二醇、1，2-丙二醇、1，3-丙二醇、1，3-己二醇中的一种或两种以上的组合。
在任意实施方式中，所述电极极片为用于正极的电极极片，所述电极浆料固含量为70～85％。
在任意实施方式中，所述电极极片为用于负极的电极极片，所述电极活性材料为负极活性材料；所述电极浆料的制备方法包括：将所述负极活性材料、导电剂和第一粘结剂按比例混合均匀后，得到粉体颗粒混合物；将所述粉体颗粒混合物与所述第二粘结剂、所述溶剂按比例混合均匀，得到所述电极浆料。
在任意实施方式中，所述电极极片为用于负极的电极极片，所述溶剂包括选自下组中的一种或两种的组合：去离子水，N-甲基吡咯烷酮(NMP)、小分子醇、酯。
在任意实施方式中，所述电极极片为用于负极的电极极片，所述溶剂为去离子水。
在任意实施方式中，所述电极极片为用于负极的电极极片，所述电极浆料固含量为65～90％。
在任意实施方式中，所述电极浆料的制备方法包括：将所述电极活性材料、导电剂和第一粘结剂按比例混合均匀后，得到粉体颗粒混合物；将所述粉体颗粒混合物与所述第二粘结剂或者所述第三粘结剂、所述溶剂按比例混合均匀，得到电极浆料。
在任意实施方式中，所述捏合的设备可采用捏合机、密炼机、螺杆挤出机等。
在任意实施方式中，所述捏合的温度25～100℃。
在任意实施方式中，所述团状物料经挤出制备得到厚片料，所述挤出的设备可采用螺杆挤出机、液压挤出机等。
在任意实施方式中，所述减薄采取辊压的方式。
在任意实施方式中，所述减薄的工艺参数包括：A/B辊速度比值1：1～2；A辊为镜面辊；B辊为粗糙辊，粗糙度为0.2～0.5μm；辊压力2～30T。
在任意实施方式中，所述厚片料经过一次或多次辊压减薄后与集流体复合即可得到电极极片。
在任意实施方式中，所述复合采取辊压的方式。
在任意实施方式中，所述复合的工艺参数包括：B/C辊速度比值1：1～2；B辊为粗糙辊，粗糙度为0.2～0.5μm；C辊为粗糙辊，粗糙度为0.6～0.9μm；辊压力2～50T。
本申请的第四方面，提供一种二次电池，其包括本申请第二方面所述的电极极片和电解液。
在任意实施方式中，所述电极极片为用于正极的电极极片，所述电极极片的厚度为50～500μm，压实密度为2.0～3.8g/cm3；和/或
所述电极极片为用于负极的电极极片，所述电极极片的厚度为50～500μm，压实密度为1.4～1.75g/cm3。
与现有技术相比，本申请具有以下有益效果：
(1)本申请提供一种电极材料，该电极材料采用特定组合的粘结剂，具有良好的粘合性和物料融合性，避免了分层现象及脱模风险。本申请提供的电极材料在制备为电极极片时，无需额外添加酯类、石油醚等有机助剂，避免了加工过程中的溶剂残留；并且无需烘干干燥的步骤，避免了粘结剂在干燥过程中上浮迁移导致厚度方向不均匀，及厚极片易开裂等问题。
(2)本申请还提供相应的电极极片，根据本申请提供的电极材料可制备得到均一性良好的厚极片，组合成二次电池可提高电芯能量密度；此外，由于该电极极片中粘合剂含量较低，从而提高了主材占比进一步增大了能量密度。
(3)本申请提供了电极极片的制备方法，该制备方法采用准干法制备得到电极极片，电极浆料的固含量较高，仅需采用捏合、挤出、减薄、与集流体复合(例如采用辊压)等工序即可完成制备；避免了湿法涂布中浆料粘度反弹大、易在过滤时堵塞滤芯等问题；无需应用占地面积较大的烘箱，有效降低了能耗。
(4)根据本申请提供的电极材料所制备得到的二次电池，具有良好的离子传输能力、倍率性能，较低的阻抗；此外还具有溶剂量较低、成本较低等优点，具有良好应用前景。
附图说明
通过阅读下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本申请的限制。在附图中：
图1：本申请一些实施例提供的锂离子电池在25℃条件下多次充放电循环过程中的电池容量保持率。
具体实施方式
下面将参照附图更详细地描述本申请的示例性实施方式。虽然附图中显示了本申请的示例性实施方式，然而应当理解，可以以各种形式实现本申请而不应被这里阐述的实施方式所限制。相反，提供这些实施方式是为了能够更透彻地理解本申请，并且能够将本申请的范围完整的传达给本领域的技术人员。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边 界。这种方式进行限定的范围是包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。
在本申请提供的具体实施方式中，提供一种电极材料，其包括电极活性材料、导电剂和粘结剂；所述粘结剂包括第一粘结剂，所述第一粘结剂包括下组中的一种或两种以上的组合：聚四氟乙烯、聚三氟氯乙烯、四氟乙烯与全氟烷基乙烯基醚共聚物、四氟乙烯与六氟丙烯共聚物、乙烯与三氟氯乙烯共聚物；所述粘结剂还包括第二粘结剂或第三粘结剂；
所述第二粘结剂包括下组中的一种或两种以上的组合：丙烯酸、丙烯酸酯、丙烯腈、丙烯酰胺中的两种或两种以上的共聚物；所述第一粘结剂与所述第二粘结剂的质量比为0～0.2：1；
所述第三粘结剂包括下组中的一种或两种以上的组合：聚偏氟乙烯、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、含氟丙烯酸酯树脂(例如丙烯酸三氟乙酯均聚物、甲基丙烯酸三氟乙酯均聚物、丙烯酸五氟丙酯均聚物等)，所述第一粘结剂与所述第三粘结剂的质量比为0.05～0.3：1。
根据本申请的实施例，通过上述技术方案，特别是应用其中特定配比的粘结剂，使得该电极材料具有良好的粘合性和物料融合性，避免了制备过程中粘结剂上浮、厚极片易开裂，避免了分层现象及脱模风险，从而可以制备得到厚极片。将该电极材料用于二次电池的电极极片，可提高主材占比、增大电芯能量密度，并且具有提高锂离子传输能力、降低阻抗、提高倍率性能的优点。
在一些实施方式中，第一粘结剂与第二粘结剂的质量比为0～0.2：1；例如在一些具体实施方式中，所述第一粘结剂不存在；在另一些具体实施方式中， 所述第一粘结剂与所述第二粘结剂的质量比可以选自0.01：1、0.02：1、0.05：1、0.1：1、0.15：1、0.2：1等。
同时采用第一粘结剂与第二粘结剂，相对于仅采用第二粘结剂，在合理配比的情况下更有利于改善电极材料制备得到的电极极片对电解液的浸润性。
在一些实施方式中，第一粘结剂与第三粘结剂的质量比为0.05～0.3：1，例如可以选自0.05：1、0.1：1、0.15：1、0.2：1、0.25：1、0.3：1等。
通过选用特定的第一粘结剂与第二粘结剂配比、第一粘结剂与第三粘结剂配比，本申请有效改善了电极材料的粘合性、物料融合性等；如不在该配比范围内，例如增加第一加粘结剂含量则降低物料融合性，膜片与集流体粘结性，增加在循环过程中脱膜风险，增第二/第三加粘结剂含量则使物料粘性增大，造成粘辊不能完成转移与集流体复合；减少第一加粘结剂含量则会降低膜片强度降低，减少第二/第三加粘结剂含量则会造成膜片粘结力降低。
在一些实施方式中，所述电极材料中，粘结剂的质量百分比为0.15～5％，例如可以选自0.15％、0.5％、1％、1.1％、1.15％、1.25％、1.3％、2％、2.7％、3％、3.5％、4％、4.5％、5％等。其中，如粘结剂的质量百分比低于0.15％，则不能制备团状物料，且不足以提供足够的粘结力；如其质量百分比高于5％，则物料粘度较大，在减薄过程中容易粘辊无法实现膜片转移。
电极活性材料的质量百分比为91～99.65％，例如91％、91.5％、92％、92.5％、93％、93.5％、94％、94.5％、95％、95.5％、96％、96.5％、97％、97.5％、98％、98.5％、99％、99.65％等；导电剂的质量百分比为0.2～4％，例如0.2％、0.5％、1％、1.5％、2％、2.5％、3％、3.5％、4％等。其中，电极活性材料和导电剂处于上述质量百分比范围时，有利于极片导电性能，同时提高活性材料占比增加能量密度。如超出上述范围，例如导电剂超出上限则导致活性主材含量降低，进而电芯能量密度降低；导电剂超出下限则极片导电能力不够，造成电芯阻抗增大，倍率性能降低。
在一些实施方式中，第二粘结剂所包含的共聚物，其重均分子量大于或等于300000；第二粘结剂所包含的共聚物中，通过极性基团之间的氢键作用形成三维交联网状结构。
通过采用重均分子量大于或等于300000的具有网状交联结构的共聚物， 提供足够能力束缚石墨颗粒形成网状结构，并且使极片具有柔韧性，在极片收卷及卷绕过程中不开裂。
在一些实施方式中，电极材料中的导电剂包括下组中的一种或两种以上的组合：导电炭黑Super P(SP)、乙炔黑、科琴黑(KB)、碳纤维、碳纳米管(CNTs)、石墨烯、导电石墨(例如KS-6、KS-15、SFG-6、MX-15等)。
在一些实施方式中，电极材料为正极材料，其包括正极活性材料、导电剂和粘结剂；该粘结剂包括第一粘结剂和第三粘结剂；其中，正极活性材料的质量百分比为93～99.65％，例如93％、93.5％、94％、94.5％、95％、95.5％、96％、96.5％、97％、97.5％、98％、98.5％、99％、99.65％等；导电剂的质量百分比为0.2～4％，，例如0.2％、0.5％、1％、1.5％、2％、2.5％、3％、3.5％、4％等；粘结剂的质量百分比为0.15～3.3％，例如0.15％、0.5％、1％、1.1％、1.15％、1.25％、1.3％、2％、2.7％、3％、3.3％等。上述各原料的质量百分比为针对正极材料进行优化后得到的。
在一优选的实施方式中，正极材料中第一粘结剂与第三粘结剂的质量比为0.05～0.3:1；例如0.05：1、0.1：1、0.15：1、0.2：1、0.25：1、0.3：1等。
在另一优选的实施方式中，正极材料中第一粘结剂的质量百分比为0.1～0.3％，例如0.1％、0.15％、0.2％、0.25％、0.3％等；第三粘结剂的质量百分比为0.3～3％，例如0.3％、0.5％、1％、1.5％、2％、2.5％、3％等。
在一些实施方式中，正极活性材料包括锂过渡金属氧化物，例如锂钴氧化物(例如LiCoO2)、锂镍氧化物(例如LiNiO2)、锂锰氧化物(例如LiMnO2、LiMn2O4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(例如LiNi1/3Co1/3Mn1/3O2，其简称为NCM333；LiNi0.5Co0.2Mn0.3O2，其简称为NCM523；LiNi0.5Co0.25Mn0.25O2，其简称为NCM211；LiNi0.6Co0.2Mn0.2O2，其简称为NCM622；LiNi0.8Co0.1Mn0.1O2，其简称为NCM811)、锂镍钴铝氧化物(例如LiNi0.85Co0.15Al0.05O2)及其改性化合物等。
在一些实施方式中，正极活性材料包括含锂磷酸盐，例如磷酸铁锂(例如LiFePO4，其简称为LFP)、磷酸铁锂与碳的复合材料、磷酸锰锂(例如LiMnPO4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料等。
在一些实施方式中，正极活性材料包括普鲁士蓝。
在一些实施方式中，正极活性材料包括层状氧化物。
在一些实施方式中，电极材料为负极材料，其包括负极活性材料、导电剂和粘结剂；所述粘结剂包括第一粘结剂和第二粘结剂；其中，负极活性材料的质量百分比为91.7～98.8％，例如91.7％、92％、92.5％、93％、93.5％、94％、94.5％、95％、95.5％、96％、96.5％、97％、97.5％、98％、98.8％等；导电剂的质量百分比为0.2～4％，，例如0.2％、0.5％、1％、1.5％、2％、2.5％、3％、3.5％、4％等；粘结剂的质量百分比为1～4.3％，例如1％、1.5％、2％、2.5％、2.7％、3％、3.5％、4％、4.3％等。上述各原料的质量百分比为针对负极材料进行优化后得到的。
在一些实施方式中，负极材料的粘结剂包括第二粘结剂，不包括第一粘结剂。
在一优选的实施方式中，负极材料中第一粘结剂与第二粘结剂的质量比为0.01～0.2：1；例如0.01：1、0.02：1、0.05：1、0.1：1、0.15：1、0.2：1等。
在另一优选的实施方式中，负极材料中第一粘结剂的质量百分比为0.05～0.3％，例如0.05％、0.1％、0.15％、0.2％、0.25％、0.3％等；第二粘结剂的质量百分比为1～4％，例如1％、1.2％、1.5％、1.7％、1.8％、1.9％、1.95％、2％、3％、4％等。
在一些实施方式中，负极活性材料包括选自下组中的一种或两种以上的组合：天然石墨、人造石墨、中间相微碳球(MCMB)、硬碳、软碳、硅、硅-碳复合物。
在一些实施方式中，提供一种电池极片，其包括集流体，和设置在该集流体上的本申请所提供的电极材料；其中，所述电极活性材料形成的物质层的孔隙率为10～45％，例如10％、15％、20％、25％、30％、35％、40％、45％等。
该孔隙率有利于增加电解液浸润速率，降低在注液后静置时间，提高生产效率降低成本，同时提高锂离子在极片中的扩散能力，降低阻抗，提高电芯倍率性能；如孔隙率不在上述范围内，则造成电芯能量密度降低，倍率及高低温性能降低。
在一些实施方式中，电极材料在电极极片上的单位面积质量为 150～600mg/1540.25mm2，例如约150mg/1540.25mm2、197mg/1540.25mm2、200mg/1540.25mm2、250mg/1540.25mm2、300mg/1540.25mm2、400mg/1540.25mm2、430mg/1540.25mm2、450mg/1540.25mm2、480mg/1540.25mm2、500mg/1540.25mm2、550mg/1540.25mm2、600mg/1540.25mm2等。
在一优选的实施方式中，该电极极片为正极极片，电极活性材料形成的物质层的孔隙率为10～45％；电极材料在电极极片上的单位面积质量为350～600mg/1540.25mm2。
在另一优选的实施方式中，该电极极片为负极极片，电极活性材料形成的物质层的孔隙率为20～45％；电极材料在电极极片上的单位面积质量为150～400mg/1540.25mm2。
在一些实施方式中，提供上述电极极片的制备方法，其包括：将溶剂、所述电极活性材料、导电剂和粘结剂按比例混合均匀后，得到电极浆料；将所述电极浆料捏合得到团状物料；将所述团状物料依次经挤出、减薄、与所述集流体复合。
在一优选的实施方式中，该制备方法中不包括烘干步骤；优选地，该电极浆料的固含量为65～90％，例如65％、70％、75％、80％、85％、90％等。当采用本申请提供的电极材料时，特别是其中特定配比的粘结剂组分，使得可以在制备电极极片时显著降低溶剂的使用量，从而避免了需要用烘干来去除溶剂的步骤，进而避免了在干燥溶剂向上挥发过程中粘结剂上浮迁移导致厚度方向分布不均、上层孔隙率降低、循环衰减快等问题。
在一些实施方式中，采用捏合机、密炼机或螺杆挤出机作为捏合的设备，捏合的温度25～100℃；采用螺杆挤出机或液压挤出机进行挤出，将团状物料挤出为厚片料；然后对厚片料采取辊压的方式进行减薄，减薄工艺优选为A/B辊速度比值1：1～2；A辊为镜面辊；B辊为粗糙辊，粗糙度为0.2～0.5μm；辊压力2～30T；然后在厚片料经减薄后与集流体进行复合，复合采取辊压的方式，其工艺优选为B/C辊速度比值1：1～2；B辊为粗糙辊，粗糙度为0.2～0.5μm；C辊为粗糙辊，粗糙度为0.6～0.9μm；辊压力2～50T。
在一些实施方式中，提供正极极片的制备方法，包括：将正极活性材料、 导电剂和第一粘结剂按比例混合均匀后，得到粉体颗粒混合物；将该粉体颗粒混合物与所述第三粘结剂、所述溶剂按比例混合均匀，得到所述电极浆料；优选地，电极浆料固含量为70～85％。
在该正极极片的制备方法中，溶剂包括选自下组中的一种或两种的组合：N-甲基吡咯烷酮(NMP)、小分子醇(碳链长度为10以下的多元醇；例如可选自1，4-丁二醇、1，3-丁二醇、2，3-丁二醇、1，2-丙二醇、1，3-丙二醇、1，3-己二醇中的一种或两种以上的组合)。
在一些实施方式中，提供负极极片的制备方法，包括：将所述负极活性材料、导电剂和第一粘结剂按比例混合均匀后，得到粉体颗粒混合物；将所述粉体颗粒混合物与所述第二粘结剂、所述溶剂按比例混合均匀，得到所述电极浆料优选地，电极浆料固含量为65～90％。
在该负极极片的制备方法中，溶剂包括选自下组中的一种或两种的组合：去离子水，N-甲基吡咯烷酮(NMP)、小分子醇(碳链长度为10以下的多元醇；例如可选自1，4-丁二醇、1，3-丁二醇、2，3-丁二醇、1，2-丙二醇、1，3-丙二醇、1，3-己二醇中的一种或两种以上的组合)、酯；优选为去离子水。
在一些实施方式中，提供一种二次电池，其包括本申请提供的电极极片和电解液；该二次电池的正极极片为本申请提供的极片，负极极片为常规市售极片；或者该二次电池的负极极片为本申请提供的极片，正极极片为常规市售极片；优选地，该二次电池的正极极片和负极极片均为本申请提供的电极极片。
本申请提供的二次电池具有较高的能量密度，电芯阻抗较小，倍率性能、循环性能较高等优点
在一些实施方式中，该二次电池中正极极片的厚度为50～500μm，压实密度为2.0～3.8g/cm3；负极极片的厚度为50～500μm，压实密度为1.4～1.75g/cm3。
实施例1
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
按照磷酸铁锂、导电炭黑Super P、聚四氟乙烯和聚偏氟乙烯的质量比为98.15：0.7：0.15：1称取各原料。将正极活性材料磷酸铁锂、导电炭黑Super P、聚四氟乙烯在双行星搅拌机中混合均匀得到无溶剂颗粒料；将聚偏氟乙烯与 N-甲基吡咯烷酮(NMP)配成胶液后与所述无溶剂颗粒料在密炼机中捏合成团状物料(浆料固含量为75％)，经过螺杆挤出成厚片料后，经过辊压减薄，并与正极集流体铝箔复合得到正极极片。该正极极片上，电极材料的单位面积质量为400mg/1540.25mm2。
(2)负极极片的制备
将负极活性材料人造石墨、乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照质量比为96.6：0.7：1.5：1.2溶于去离子水中，充分搅拌混合均匀后得到负极浆料(浆料固含量为50％)；将负极浆料涂布于负极集流体铜箔，经烘干冷压后制备负极极片。该负极极片上，电极材料的单位面积质量为197mg/1540.25mm2。
(3)二次电池制备
将上述正极极片、作为隔离膜的14μm厚的聚乙烯膜、上述负极极片依次层叠好，使隔离膜处于正极极片与负极极片之间起到隔离的作用，并卷绕得到裸电芯。将裸电芯置于外包装中，经干燥后注入电解液，再依次经过真空封装、静置、化成、整形等工序后，制备得到锂离子电池。
实施例2
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
除以下区别之外，同实施例1中步骤(1)正极极片的制备方法：磷酸铁锂、导电炭黑Super P、聚四氟乙烯和聚偏氟乙烯的质量比为98.2：0.7：0.1：1。
(2)负极极片的制备
按照人造石墨、导电炭黑Super P、丙烯酸-丙烯酰胺-丙烯腈共聚物的质量比为97.3：0.7：2称取各原料。将人造石墨和导电炭黑Super P在双行星搅拌机中混合均匀得到无溶剂颗粒料；将丙烯酸-丙烯酰胺-丙烯腈共聚物、去离子水和该无溶剂颗粒料在密炼机中捏合成团状物料(浆料固含量为70％)，经过螺杆挤出成厚片料后，经过辊压减薄，并与负极集流体铜箔复合得到负极极片。该负极极片上，电极材料的单位面积质量为197mg/1540.25mm2。
(3)二次电池制备
同实施例1中步骤(3)二次电池制备方法。
实施例3
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
除以下区别之外，同实施例1中步骤(1)正极极片的制备方法：磷酸铁锂、导电炭黑Super P、聚四氟乙烯和聚偏氟乙烯的质量比为98.2：0.7：0.15：1。
(2)负极极片的制备
同实施例2中步骤(2)负极极片的制备方法。
(3)二次电池制备
同实施例2中步骤(3)二次电池制备。
实施例4
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
除以下区别之外，同实施例1中步骤(1)正极极片的制备方法：磷酸铁锂、导电炭黑Super P、聚四氟乙烯和聚偏氟乙烯的质量比为98.05：0.7：0.25：1。
(2)负极极片的制备
同实施例2中步骤(2)负极极片的制备方法。
(3)二次电池制备
同实施例2中步骤(3)二次电池制备。
实施例5
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
除以下区别之外，同实施例1中步骤(1)正极极片的制备方法：磷酸铁锂、导电炭黑Super P、聚四氟乙烯和聚偏氟乙烯的质量比为98：0.7：0.3：1。
(2)负极极片的制备
同实施例2中步骤(2)负极极片的制备方法。
(3)二次电池制备
同实施例2中步骤(3)二次电池制备。
实施例6
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
将磷酸铁锂、聚偏氟乙烯和乙炔黑按照质量比为97.3：2：0.7溶于溶剂N-甲基吡咯烷酮(NMP)中，充分搅拌混合均匀后得到正极浆料(浆料固含量为63％)；将正极浆料涂布于正极集流体铝箔，经烘干冷压后制备得到正极极片。该正极极片上，电极材料的单位面积质量为400mg/1540.25mm2。
(2)负极极片的制备
同实施例2中步骤(2)负极极片的制备方法。
(3)二次电池制备
同实施例2中步骤(3)二次电池制备。
实施例7
提供一种锂离子电池，除负极极片按以下步骤制备之外，其制备方法同
实施例6：
按照人造石墨、导电炭黑Super P、聚四氟乙烯、丙烯酸-丙烯酰胺-丙烯腈共聚物的质量比为97.3：0.7：0.05：1.95称取各原料。将人造石墨、导电炭黑Super P、聚四氟乙烯在双行星搅拌机中混合均匀得到无溶剂颗粒料；将丙烯酸-丙烯酰胺-丙烯腈共聚物、去离子水与该无溶剂颗粒料在密炼机中捏合成团状物料(浆料固含量为70％)，经过螺杆挤出成厚片料后，经过辊压减薄，并与负极集流体铜箔复合得到负极极片。该负极极片上，电极材料的单位面积质量为197mg/1540.25mm2。
实施例8
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
同实施例6中步骤(1)正极极片的制备方法。
(2)负极极片的制备
除以下区别之外，同实施例7中步骤(2)负极极片的制备方法：人造 石墨、导电炭黑Super P、聚四氟乙烯、丙烯酸-丙烯酰胺-丙烯腈共聚物的质量比为97.3：0.7：0.1：1.9。
(3)二次电池制备
同实施例6中步骤(3)二次电池制备。
实施例9
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
同实施例6中步骤(1)正极极片的制备方法。
(2)负极极片的制备
除以下区别之外，同实施例7中步骤(2)负极极片的制备方法：人造石墨、导电炭黑Super P、聚四氟乙烯、丙烯酸-丙烯酰胺-丙烯腈共聚物的质量比为97.3：0.7：0.2：1.8。
(3)二次电池制备
同实施例6中步骤(3)二次电池制备。
实施例10
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
同实施例6中步骤(1)正极极片的制备方法。
(2)负极极片的制备
除以下区别之外，同实施例7中步骤(2)负极极片的制备方法：人造石墨、导电炭黑Super P、聚四氟乙烯、丙烯酸-丙烯酰胺-丙烯腈共聚物的质量比为97.3：0.7：0.3：1.7。
(3)二次电池制备
同实施例6中步骤(3)二次电池制备。
实施例11
提供一种锂离子电池，其正极极片及二次电池制备方法同实施例1，负极极片制备方法同实施例9。
实施例12
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
除以下区别之外，同实施例1中步骤(1)正极极片的制备方法：电极材料的单位面积质量为430mg/1540.25mm2。
(2)负极极片的制备
除以下区别之外，同实施例9中步骤(2)负极极片的制备方法：电极材料的单位面积质量为212mg/1540.25mm2。
(3)二次电池的制备
同实施例1中步骤(3)二次电池的制备方法。
实施例13
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
除以下区别之外，同实施例1中步骤(1)正极极片的制备方法：电极材料的单位面积质量为450mg/1540.25mm2。
(2)负极极片的制备
除以下区别之外，同实施例9中步骤(2)负极极片的制备方法：电极材料的单位面积质量为222mg/1540.25mm2。
(3)二次电池的制备
同实施例1中步骤(3)二次电池的制备方法。
实施例14
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
除以下区别之外，同实施例1中步骤(1)正极极片的制备方法：电极材料的单位面积质量为480mg/1540.25mm2。
(2)负极极片的制备
除以下区别之外，同实施例9中步骤(2)负极极片的制备方法：电极材料的单位面积质量为237mg/1540.25mm2。
(3)二次电池的制备
同实施例1中步骤(3)二次电池的制备方法。
对比例1
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
除以下区别之外，同实施例6中步骤(1)正极极片的制备方法：电极材料的单位面积质量为400mg/1540.25mm2。
(2)负极极片的制备
除以下区别之外，同实施例1中步骤(2)负极极片的制备方法：电极材料的单位面积质量为197mg/1540.25mm2。
(3)二次电池的制备
同实施例1中步骤(3)二次电池的制备方法。
对比例2
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
除以下区别之外，同实施例6中步骤(1)正极极片的制备方法：电极材料的单位面积质量为430mg/1540.25mm2。
(2)负极极片的制备
除以下区别之外，同实施例1中步骤(2)负极极片的制备方法：电极材料的单位面积质量为212mg/1540.25mm2。
(3)二次电池的制备
同实施例1中步骤(3)二次电池的制备方法。
对比例3
提供一种锂离子电池，其制备方法如下：
(1)正极极片的制备
除以下区别之外，同实施例6中步骤(1)正极极片的制备方法：电极材料的单位面积质量为450mg/1540.25mm2。
(2)负极极片的制备
除以下区别之外，同实施例1中步骤(2)负极极片的制备方法：电极材料的单位面积质量为222mg/1540.25mm2。
(3)二次电池的制备
同实施例1中步骤(3)二次电池的制备方法。
实验例
对实施例和对比例制备得到的锂离子电池进行测试，具体如下：
(1)析理测试
1C电流恒流充电到3.65V，然后在3.65V下恒压充电至电流0.05C，静置5min，然后以1C电流恒流放电到2.5V，以上为电池的一个充放电循环，循环10圈后，在3.65V下恒压充电至电流0.05C。在干燥环境中将电池拆解，负极极片表面金黄色表示未析理，有银白色区域出现表示析理。
(2)电解液浸润速率测试
测试方法：用毛细管(直径1mm)吸取一定量电解液(2cm高度)，使毛细管吸液端与电极极片表面接触。电极极片为多孔结构，在毛细作用力下，可将毛细管中的电解液吸出，记录电解液被完全吸收所需要的时间，由此通过计算得到电解液浸润速率。
电解液浸润速率计算方法：电解液密度*毛细管中电解液体积/电解液被完全吸收所需要的时间。
测试结果如表1所示。
表1锂离子电池正负极析理、电解液浸润速率检测结果

(3)倍率性能测试
倍率放电：0.33C充电至3.65V恒定电压充电至电流为0.05C，静置5分钟，0.33C放电至2.5V并测定其间的放电容量，静置30分钟；0.33C充电至3.65V恒定电压充电至电流为0.05C，静置5分钟，1C放电至2.5V并测定其间的放电容量，静置30分钟；0.33C充电至3.65V恒定电压充电至电流为0.05C，静置5分钟，3C放电至2.8V并测定其间的放电容量，静置30分钟；0.33C充电至3.65V恒定电压充电至电流为0.05C，静置5分钟，5C放电至2.5V并测定其间的放电容量，静置30分钟。
倍率充电：0.33C充电至3.65V恒定电压充电至电流为0.05C，静置5分钟，0.33C放电至2.5V，并测定其间的充电容量，静置30分钟；1C充电至3.65V恒定电压充电至电流为0.05C，静置30分钟，0.33C放电至2.5V并测定其间的充电容量，静置30分钟；3C充电3.65V恒定电压充电至电流为0.05C，静置5分钟，0.33C放电至2.5V并测定其间的充电容量，静置30分钟；5C充电至4.2V恒定电压充电至电流为0.05C，静置30分钟，0.33C放电至2.5V并测定其间的充电容量，静置30分钟。
测试结果如表2所示。
表2锂离子电池充放电倍率测试结果

(4)DCR性能测试
测试方法：
在25℃下，0.33C充电至满充状态，然后0.33C放电0.1Cn(Cn表示电池容量)而将二次电池调节至90％SOC，静置30分钟，静置结束电压V1，之后3C放电30秒，放电截止电压V2，静置40秒，3C充电30秒；
在25℃下，0.33C充电至满充状态，然后0.33C放电0.5Cn(Cn表示电池容量)而将二次电池调节至50％SOC，静置30分钟，静置结束电压V1，之后3C放电30秒，放电截止电压V2，之后3C放电30秒，静置40秒，3C充电30秒；
在25℃下，0.33C充电至满充状态，然后0.33C放电0.9Cn(Cn表示电池容量)而将二次电池调节至20％SOC，静置30分钟，静置结束电压V1，之后3C放电30秒，放电截止电压V2，之后3C放电30秒，静置40秒，3C充电30秒；
计算方法：DCR＝(V1-V2)/I，其中V1静置结束电压，V2放电截止电压，I是放电电流。测试结果如表3所示。
表3锂离子电池DCR性能测试结果

(5)电池循环寿命测试
在25℃下，对所有实施例和对比例的锂离子电池进行充放电测试。一个充放电循环过程如下：1C电流恒流充电到3.65V，然后在3.65V下恒压充电至电流0.05C，静置5min，然后以1C电流恒流放电到2.5V，记录此时电池容量为C1，以上为电池的一个充放电循环，按照上述过程循环。循环过程中锂离子电池容量保持率见图1所示。
(6)极片孔隙率测试
将装有样品的样品杯，置于真密度测试仪，密闭测试系统，按程序通入氦气，通过检测样品室和膨胀室中的气体的压力，再根据玻尔定律(PV＝nRT)来计算真实体积V1，用镊子选用>20片外观良好，边缘无掉粉的圆片装入样品杯。记录片数，计算表观体积V2，V2＝S*H*A，式中：S-面积,cm2；H-厚度,cm；A-样品数,EA；
孔隙率计算方法：孔隙率P＝(V2-V1)/V2*100％，式中，V1-样品真体积,cm3,测试得到；V2-样品表观体积,cm3。极片孔隙率检测结果如表4所示。
表4极片孔隙率检测结果
以上所述，仅为本申请较佳的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (17)

  1. 一种电极材料，其特征在于，所述电极材料包括电极活性材料、导电剂和粘结剂；所述粘结剂包括第一粘结剂，所述第一粘结剂包括下组中的一种或两种以上的组合：聚四氟乙烯、聚三氟氯乙烯、四氟乙烯-全氟烷基乙烯基醚共聚物、四氟乙烯-六氟丙烯共聚物、乙烯-三氟氯乙烯共聚物；所述粘结剂还包括第二粘结剂或第三粘结剂；
    所述第二粘结剂包括下组中的一种或两种以上的组合：丙烯酸、丙烯酸酯、丙烯腈、丙烯酰胺中的两种或两种以上的共聚物；所述第一粘结剂与所述第二粘结剂的质量比为0～0.2：1；
    所述第三粘结剂包括下组中的一种或两种以上的组合：聚偏氟乙烯、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、含氟丙烯酸酯树脂；所述第一粘结剂与所述第三粘结剂的质量比为0.05～0.3：1。
  2. 如权利要求1所述的电极材料，其特征在于，所述电极材料中，所述粘结剂的质量百分比为0.15～5％。
  3. 如权利要求1所述的电极材料，其特征在于，所述第一粘结剂与第二粘结剂的质量比为0.01～0.2：1；所述第一粘结剂与第三粘结剂的质量比为0.1～0.3：1。
  4. 如权利要求1所述的电极材料，其特征在于，所述电极材料中，所述电极活性材料的质量百分比为91～99.65％，所述导电剂的质量百分比为0.2～4％，所述粘结剂的质量百分比为0.15～5％。
  5. 如权利要求1所述的电极材料，其特征在于，所述第二粘结剂所包含的共聚物，其重均分子量大于或等于300000。
  6. 如权利要求1所述的电极材料，其特征在于，所述导电剂包括下组中的一种或两种以上的组合：导电炭黑Super P、乙炔黑、科琴黑、碳纤维、碳纳米管、石墨烯、导电石墨。
  7. 如权利要求1～6任一项所述的电极材料，其特征在于，所述电极活性材料为正极活性材料，所述粘结剂包括第一粘结剂和第三粘结剂。
  8. 如权利要求7所述的电极材料，其特征在于，所述正极活性材料包括下组中的一种或两种以上的组合：锂过渡金属氧化物、含锂磷酸盐、普鲁士蓝、层状氧化物；
    优选地，所述锂过渡金属氧化物包括选自下组中的一种或两种以上的组合：锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物及其改性化合物；
    优选地，所述含锂磷酸盐包括选自下组中的一种或两种以上的组合：磷酸铁锂、磷酸铁锂与碳的复合材料、磷酸锰锂、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料。
  9. 如权利要求1-6任一项所述的电极材料，其特征在于，所述电极活性材料为负极活性材料，所述粘结剂包括第一粘结剂和第二粘结剂。
  10. 如权利要求9所述的电极材料，其特征在于，所述负极活性材料包括选自下组中的一种或两种以上的组合：天然石墨、人造石墨、中间相微碳球、硬碳、软碳、硅、硅-碳复合物。
  11. 一种电池极片，其特征在于，包括权利要求1～10任一项所述的电极材料和集流体，所述电极材料设置于所述集流体上。
  12. 如权利要求11所述的电极极片，其特征在于，在所述电极极片上，所述电极活性材料形成的物质层的孔隙率为10～45％；所述电极材料的单位面积质量为150～600mg/1540.25mm2。
  13. 如权利要求12所述的电极极片，其特征在于，所述电极活性材料为正极活性材料；其中，所述正极活性材料形成的物质层的孔隙率为10～45％，所述电极材料的单位面积质量为350～600mg/1540.25mm2；或者，
    所述电极活性材料为负极活性材料；其中，所述负极活性材料形成的物质层的孔隙率为20～45％，所述电极材料的单位面积质量为150～400mg/1540.25mm2。
  14. 权利要求11～13任一项所述的电极极片的制备方法，其特征在于，包括：将溶剂、所述电极活性材料、导电剂和粘结剂按比例混合均匀后制备得到电极浆料；将所述电极浆料捏合得到团状物料；将所述团状物料依次经挤出、减薄、与所述集流体复合。
  15. 如权利要求14所述的制备方法，其特征在于，所述电极浆料的固含量为65～90％；优选地，所述制备方法不包括烘干步骤。
  16. 如权利要求14所述的制备方法，其特征在于，所述电极活性材料为正极活性材料，所述溶剂包括选自下组中的一种或两种的组合：N-甲基吡咯烷酮、小分子醇；或者，
    所述电极活性材料为负极活性材料，所述溶剂包括选自下组中的一种或两种的组合：去离子水，N-甲基吡咯烷酮、小分子醇、酯。
  17. 一种二次电池，其特征在于，所述二次电池包括权利要求1～10任一项所述的电极材料和/或权利要求11～13任一项所述的电池极片。
PCT/CN2023/079056 2022-06-14 2023-03-01 电极材料、电极极片及其制备方法、二次电池 WO2023241104A1 (zh)

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