CN116504921B - Positive electrode sheet, electrochemical device, and electricity consumption device - Google Patents

Positive electrode sheet, electrochemical device, and electricity consumption device Download PDF

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CN116504921B
CN116504921B CN202310737675.3A CN202310737675A CN116504921B CN 116504921 B CN116504921 B CN 116504921B CN 202310737675 A CN202310737675 A CN 202310737675A CN 116504921 B CN116504921 B CN 116504921B
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positive electrode
active material
electrode active
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positive
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CN116504921A (en
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张磊成
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Weilai Battery Technology Anhui Co ltd
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Weilai Battery Technology Anhui Co ltd
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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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The application provides a positive electrode plate, an electrochemical device and an electricity utilization device, wherein the positive electrode plate comprises a positive electrode current collector and a positive electrode active material layer positioned on the surface of the positive electrode current collector, and the transmission coefficient F of the positive electrode plate meets the following conditions: f is more than or equal to 70 and less than or equal to 130,wherein I is a shuffling factor, i=i (003) /I (104) ，I (003) Is the peak intensity of the (003) -plane diffraction peak in the X-ray diffraction pattern of the positive electrode active material in the positive electrode active material layer, I (104) Peak intensity of (104) plane diffraction peak; t is the particle strength of the positive electrode active material in MPa; s is the tortuosity of the positive electrode active material layer; dv 50 The median particle diameter of the positive electrode active material is expressed in [ mu ] m. The positive plate is beneficial to improving the capacity, the cycle performance and the multiplying power performance of the lithium ion battery and improving the comprehensive performance of the lithium ion battery.

Description

Positive electrode sheet, electrochemical device, and electricity consumption device
Technical Field
The application relates to the field of energy storage, in particular to a positive electrode plate, an electrochemical device and an electric device.
Background
Among commercial rechargeable batteries, lithium ion batteries have higher energy density and wider operating voltage, and are widely applied to aspects such as electric automobiles, digital 3C, energy storage and the like. The cost, lifetime, safety, etc. characteristics of lithium ion batteries have been the focus of attention of researchers. Safety performance, cycle performance and calendar life are key to whether the lithium ion battery can be applied to an electric automobile.
In the design and manufacturing process of the lithium ion battery pole piece, the active material layer is densified by adopting a rolling mode and the like, so that the volume energy density of a final battery core is improved, meanwhile, contact among particles and adhesion between the particles and a current collector are promoted, and ionic electron conduction of an interface is facilitated. However, the too high density of pole piece particles can reduce the porosity of the pole piece and affect the wettability of the electrolyte to the pole piece; meanwhile, extrusion deformation of pore channels among pole piece particles can be caused, conduction of interfacial lithium ions in the electrochemical reaction process is hindered, and mismatching of ion transmission and electrode reaction is caused, so that electrochemical performance and cycle performance of the battery cell are deteriorated.
Disclosure of Invention
In view of the foregoing problems of the prior art, the present application provides a positive electrode tab and an electrochemical device. The application effectively improves the electrochemical performance and the cycle performance of the electrochemical device by matching the tortuosity of the positive electrode plate and the mixing factor, the particle strength and the median particle diameter of the positive electrode active material.
The first aspect of the application provides a positive electrode plate, which comprises a positive electrode current collector and a positive electrode active material layer positioned on the surface of the positive electrode current collector, wherein the transmission coefficient F of the positive electrode plate meets the following conditions: f is more than or equal to 70 and less than or equal to 130,
wherein I is a shuffling factor, i=i (003) /I (104) ，I (003) Is the peak intensity of the (003) -plane diffraction peak in the X-ray diffraction pattern of the positive electrode active material in the positive electrode active material layer, I (104) Peak intensity of (104) plane diffraction peak; t is the particle strength of the positive electrode active material in MPa; s is the tortuosity of the positive electrode active material layer; dv 50 The median particle diameter of the positive electrode active material is expressed in [ mu ] m.
A second aspect of the present application provides an electrochemical device comprising the aforementioned positive electrode sheet.
A third aspect of the present application provides an electrical device comprising the aforementioned electrochemical device.
The technical scheme of the application can realize the following beneficial effects:
the application adjusts and controls the mixed factor I, the particle strength t and the median diameter Dv of the positive electrode active material 50 The relation with the tortuosity s of the positive electrode plate is controlled, so that the transmission coefficient F of the positive electrode plate is controlled to be less than or equal to 70 and less than or equal to 130, the transmission of lithium ions in particles and among the particles can be promoted, the transmission rate is improved, and the rate capability of an electrochemical device is improved; in addition, through reasonable particle size and particle strength, stable pore channel structure can be formed among positive electrode active material particles, and the wettability of electrolyte to the electrode plate is improved, so that ion transmission is matched with electrode reaction, and the electrochemistry is improvedThe energy density of the device, the impedance is reduced, and the cycle performance is improved.
Drawings
The application will be further illustrated and described with reference to the following drawings, it being understood that the drawings serve only as examples and are not intended to limit the technical solution of the application.
FIG. 1 is an X-ray diffraction pattern (XRD) of a positive electrode active material according to an embodiment of the present application;
fig. 2 is a surface scanning electron microscope image of a positive electrode sheet formed when the positive electrode active material of the embodiment of the present application is a primary particle.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be clearly and completely described below with reference to the embodiments, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. The related embodiments described herein are of illustrative nature and are intended to provide a basic understanding of the application. The embodiments of the present application should not be construed as limiting the application.
For simplicity, only a few numerical ranges are specifically disclosed herein. However, any lower limit may be combined with any upper limit to form a range not explicitly recited; and any lower limit may be combined with any other lower limit to form a range not explicitly recited, and any upper limit may be combined with any other upper limit to form a range not explicitly recited. Furthermore, each separately disclosed point or individual value may itself be combined as a lower limit or upper limit with any other point or individual value or with other lower limit or upper limit to form a range not explicitly recited.
In the description herein, unless otherwise indicated, "above", "below" includes this number.
Unless otherwise indicated, terms used in the present application have well-known meanings commonly understood by those skilled in the art. Unless otherwise indicated, the numerical values of the parameters set forth in the present application may be measured by various measurement methods commonly used in the art (e.g., may be tested according to the methods set forth in the examples of the present application).
The list of items to which the term "at least one of," "at least one of," or other similar terms are connected may mean any combination of the listed items. For example, if items a and B are listed, the phrase "at least one of a and B" means only a; only B; or A and B. In another example, if items A, B and C are listed, then the phrase "at least one of A, B and C" means only a; or only B; only C; a and B (excluding C); a and C (excluding B); b and C (excluding A); or A, B and C. Item a may comprise a single component or multiple components. Item B may comprise a single component or multiple components. Item C may comprise a single component or multiple components.
The term "silicon-based material" is not particularly limited as long as silicon is contained in the material. In the present application, the "silicon-based material" may be silicon, silicon alloy, silicon oxygen compound, silicon carbon compound, or any mixture of the above silicon-based materials.
The term "carbon-based material" is not particularly limited and may be graphite, soft carbon, hard carbon, carbon nanotubes, graphene, and any mixture of the foregoing carbon-based materials. Wherein the term "graphite" is not particularly limited, and may be artificial graphite and/or natural graphite.
The application is further described below in conjunction with the detailed description. It should be understood that the detailed description is intended by way of illustration only and is not intended to limit the scope of the application.
1. Positive electrode plate
The first aspect of the application provides a positive electrode plate, which comprises a positive electrode current collector and a positive electrode active material layer positioned on the surface of the positive electrode current collector, wherein the transmission coefficient F of the positive electrode plate meets the following conditions: f is more than or equal to 70 and less than or equal to 130,
wherein, referring to fig. 1, I is a shuffling factor, i=i (003) /I (104) ，I (003) Is the positive electrode active material in the positive electrode active material layerPeak intensity of (003) -plane diffraction peak in X-ray diffraction pattern of material, I (104) Peak intensity of (104) plane diffraction peak; t is the particle strength of the positive electrode active material in MPa; s is the tortuosity of the positive pole piece; dv 50 The median particle diameter of the positive electrode active material is expressed in μm.
The application adjusts and controls the mixed factor I, the particle strength t and the median diameter Dv of the positive electrode active material 50 The relation with the tortuosity s of the positive electrode plate is controlled, so that the transmission coefficient F of the positive electrode plate is controlled to be less than or equal to 70 and less than or equal to 130, the transmission of lithium ions in particles and among the particles can be promoted, the transmission rate is improved, and the rate capability of an electrochemical device is improved; in addition, through reasonable particle size and particle strength, stable pore channel structures can be formed among positive electrode active material particles, and the wettability of electrolyte to the electrode plate is improved, so that ion transmission is matched with electrode reaction, and the energy density, impedance and cycle performance of the electrochemical device are improved.
The transmission coefficient F of the positive electrode sheet is, for example, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130 or a range of any two values.
In some embodiments, the transmission coefficient F of the positive electrode sheet also satisfies: f is more than or equal to 80 and less than or equal to 120. The positive electrode sheet has a transmission coefficient F of 82, 84, 86, 88, 92, 94, 96, 98, 102, 104, 106, 108, 112, 114, 116, 118 or a range of any two values.
In some embodiments, the shuffling factor I satisfies: i is more than or equal to 1.5 and less than or equal to 2.5; illustratively, the shuffling factor I is 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 or a range of any two of the values mentioned above.
It is understood that the higher the I value, the lower the lithium nickel miscibility in general, the peak intensity ratio of (003) to (104) in the XRD diffractogram of the ternary material. If the lithium nickel mixed discharge degree is too low, interface side reaction is easy to occur, lithium ions are consumed, and an inactive phase is generated; if the lithium nickel is too high in mixed discharge degree, lithium ion conduction is hindered, and active lithium is lost more. The control of I in the above range is not only favorable for the conduction of lithium ions, but also can avoid the generation of inactive phases, thereby improving the electrochemical performance and the cycle performance of the electrochemical device.
In some embodiments, the shuffling factor I satisfies: i is more than or equal to 1.7 and less than or equal to 2.4; illustratively, the shuffling factor I is 1.75, 1.85, 1.95, 2.05, 2.15, 2.25, 2.35 or a range of any two of the foregoing values.
In some embodiments, the particle strength t of the positive electrode active material satisfies: t is more than or equal to 120 and less than or equal to 300; the particle strength t is illustratively 120 MPa, 130 MPa, 140 MPa, 150 MPa, 160 MPa, 170 MPa, 180 MPa, 190 MPa, 200 MPa, 210 MPa, 220 MPa, 230 MPa, 240 MPa, 250 MPa, 260 MPa, 270 MPa, 280 MPa, 290 MPa, 300 MPa or a range of any two of the foregoing values.
It can be understood that the particle strength t of the positive electrode active material reflects the hardness of the active particles themselves. The higher hardness particles can maintain the shape integrity without breaking when being rolled, but at the same time, the higher positive pole piece compaction density is more difficult to reach, and the thickness of the final positive pole piece is influenced. The particle strength t is controlled within the range, so that the structural stability of the positive electrode active material can be ensured, the formation of a proper pore channel structure of the positive electrode active material layer can be realized, the wettability of the positive electrode plate can be improved, and the comprehensive performance of the electrochemical device can be improved.
In some embodiments, the particle strength t of the positive electrode active material satisfies: 150 T is more than or equal to MPa and less than or equal to 270 MPa; illustratively, the particle strength t of the positive electrode active material is 155 MPa, 165 MPa, 175 MPa, 185 MPa, 195 MPa, 205 MPa, 215 MPa, 225 MPa, 235 MPa, 245 MPa, 255 MPa, 265 MPa, or a range of any two of the above numerical compositions.
In some embodiments, the tortuosity s of the positive pole piece satisfies: s is more than or equal to 1.2 and less than or equal to 4.0; illustratively, the cathode sheet has a tortuosity s of 1.2, 1.3, 1.4, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.5, 2.6, 2.8, 3.0, 3.2, 3.4, 3.5, 3.6, 3.8, 4.0, or a range of any two of the foregoing values.
The tortuosity can adopt X-ray tomography/cross-section scanning electron microscope andthe calculation is carried out in a simulation and analog combination mode, and a fitting formula adopts tau=f -α Where f is the proportionality coefficient, ε is the porosity of the pole piece, and α is the Bruggeman index. The tortuosity of the pole piece is related to the network structure of the porous electrode piece, is closely related to the shape and the particle size distribution of material particles, the design and the processing surface density, compaction and the like of the pole piece, and is designed in the research and development and production processes, so that the tortuosity can be adjusted within a reasonable range, and the rapid conduction of a large amount of lithium ions is facilitated, so that the high energy density, the good multiplying power and the good cycle performance are realized. It can be appreciated that too small tortuosity τ may affect the electrical contact between particles and the pole piece has poor liquid retention capacity; if the tortuosity τ is too large, the conduction path is too long, and the shuttle of lithium ions is hindered. The tortuosity can be regulated and controlled by regulating rolling conditions, such as rolling pressure and roll gap size.
In some embodiments, the tortuosity s of the positive pole piece satisfies: s is more than or equal to 1.8 and less than or equal to 3.0; illustratively, the cathode sheet has a tortuosity s of 1.85, 1.95, 2.05, 2.15, 2.25, 2.35, 2.45, 2.55, 2.65, 2.75, 2.85, 2.95, or a range of any two of the foregoing values.
In some embodiments, the median particle diameter Dv of the positive electrode active material 50 The method meets the following conditions: 0.5 Mu m is less than or equal to Dv 50 Less than or equal to 7 mu m; exemplary, median particle diameter Dv 50 The range is 0.5 [ mu ] m, 1.0 [ mu ] m, 1.5 [ mu ] m, 2.0 [ mu ] m, 2.5 [ mu ] m, 3.0 [ mu ] m, 3.5 [ mu ] m, 4.0 [ mu ] m, 4.5 [ mu ] m, 5.0 [ mu ] m, 5.5 [ mu ] m, 6.0 [ mu ] m, 6.5 [ mu ] m, 7.0 [ mu ] m or any two values of the foregoing.
It will be appreciated that Dv 50 The particle size of the particles is reflected in the median particle size of the positive electrode active material used on a volume basis, i.e., the particle size corresponding to the cumulative particle size distribution percentage reaching 50%. The larger the particle size of the positive electrode active material is, the easier the realization of higher compaction density is, which is beneficial to the improvement of gram capacity of the lithium battery; however, when the particle size of the positive electrode active material is too large, the specific surface area of the positive electrode active material becomes relatively small, and wettability and reactivity of the positive electrode active material are reduced. Further, dv 50 In the above range, is advantageousThe thickness of the positive pole piece is reasonably controlled.
In some embodiments, the median particle diameter Dv 50 The method meets the following conditions: 1.5 Mu m is less than or equal to Dv 50 Less than or equal to 5 mu m; exemplary, median particle diameter Dv 50 The [ mu ] m is 1.6 [ mu ] m, 1.8 [ mu ] m, 2.2 [ mu ] m, 2.4 [ mu ] m, 2.6 [ mu ] m, 2.8 [ mu ] m, 3.2 [ mu ] m, 3.4 [ mu ] m, 3.6 [ mu ] m, 3.8 [ mu ] m, 4.2 [ mu ] m, 4.4 [ mu ] m, 4.6 [ mu ] m, 4.8 [ mu ] m or a range formed by any two values.
In some embodiments, the areal density m of the positive electrode sheet satisfies: 40 mg/cm 2 ≤m≤65 mg/cm 2 The method comprises the steps of carrying out a first treatment on the surface of the Exemplary, the positive electrode sheet has an areal density m of 40 mg/cm 2 、45 mg/cm 2 、50 mg/cm 2 、55 mg/cm 2 、60 mg/cm 2 、65 mg/cm 2 Or a range of any two values recited above. The surface density of the positive electrode sheet here means the double-sided density in the case where the current collector is coated with the active material on both sides, and the single-sided density of the positive electrode sheet in the case where the current collector is coated with the active material on only one side is 20 mg/cm 2 ~30 mg/cm 2 。
The areal density can be adjusted by controlling the flow rate of the slurry; the higher the surface density of the positive electrode plate is, the thicker the electrode plate is under the same compacted density, and the compacted density can be changed by changing rolling conditions, such as rolling pressure, roll gap size and the like, so as to further improve the surface density.
In some embodiments, the areal density m of the positive electrode active material layer satisfies: 45 mg/cm 2 ≤m≤60m g/cm 2 The method comprises the steps of carrying out a first treatment on the surface of the Exemplary, the positive electrode active material layer has an areal density m of 46 mg/cm 2 、48 mg/cm 2 、52 mg/cm 2 、54 mg/cm 2 、56 mg/cm 2 、58 mg/cm 2 Or a range of any two values recited above.
In some embodiments, the average thickness h of the positive electrode active material layer satisfies: 112. h is less than or equal to 156 mu m; the average thickness h of the positive electrode active material layer is, illustratively, 112 μm, 114 μm, 116 μm, 118 μm, 120 μm, 122 μm, 124 μm, 126 μm, 128 μm, 130 μm, 132 μm, 134 μm, 136 μm, 138 μm, 140 μm, 142 μm, 144 μm, 146 μm, 148 μm, 150 μm, 152 μm, 154 μm, 156 μm or a range of any two of the above numerical values. In some embodiments, the average thickness h of the positive electrode active material layer satisfies: 120. h is less than or equal to 143 mu m; the average thickness h of the positive electrode active material layer is, for example, 121 μm, 123 μm, 125 μm, 127 μm, 129 μm, 131 μm, 133 μm, 135 μm, 137 μm, 139 μm, 141 μm, 143 μm or a range of any two of the above numerical values. The average thickness of the positive electrode active material layer directly influences the transmission of ions in the positive electrode active material layer, and the thicker the positive electrode active material layer is, the higher the difficulty of the transmission of ions from the surface to the deepest inside of the positive electrode plate is, and the higher the ion transmission resistance is.
In some embodiments, the positive electrode active material includes primary particles (e.g., monocrystalline particles, see fig. 2); or at least one of secondary particles (e.g., polycrystalline particles). In this context, "primary particles" refer to crystals that do not contain grain boundaries over a few μm scale, the crystallographic orientation of which remains substantially uniform throughout the interior; "secondary particles" refers to a collection of primary particles of numerous oriented grains, the interior of which is based on a lattice-type periodic structure, but is isotropic.
It is understood that primary particles have better strength and stability than secondary particles, and have better processability when rolled, and also maintain higher capacity retention in circulation. The application reasonably optimizes the particle size, the particle strength, the mixing degree, the tortuosity of the positive electrode plate and the like of the positive electrode active material, so that better electrochemical performance and cycle performance can be realized.
In some embodiments, the positive electrode active material includes, but is not limited to, at least one of nickel cobalt-based ternary materials.
In some embodiments, the nickel cobalt-based ternary material includes, but is not limited to, li a Ni m Co n A (1-m-n) O 2 At least one of the materials, wherein A comprises at least one of manganese, aluminum, magnesium, chromium, calcium, zirconium, molybdenum, silver or niobium, a is more than or equal to 0.9 and less than or equal to 1.2,0.5 and less than or equal to m and less than or equal to 1, n is more than or equal to 0 and less than or equal to 0.5, and m+n is more than or equal to 1.
In some embodiments, the positive electrode active material includes, but is not limited to, at least one of lithium nickel oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium nickel manganese cobalt magnesium oxide, lithium nickel manganese oxide.
In some embodiments, the positive electrode active material layer further includes a binder and a conductive agent, the mass ratio of the positive electrode active material, the binder, and the conductive agent satisfying: (90-98): (1-5), the proportion of the binder and the conductive agent being adjustable, the embodiment of the application being not particularly limited.
In some embodiments, the binder includes, but is not limited to: at least one of polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, an ethyleneoxy-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, or the like.
In some embodiments, the conductive material includes, but is not limited to: at least one of carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof. In some embodiments, the carbon-based material comprises natural graphite, synthetic graphite, carbon black, acetylene black, ketjen black, carbon fiber, or any combination thereof. In some embodiments, the metal-based material is selected from metal powder, metal fiber, copper, nickel, aluminum, or silver. In some embodiments, the conductive polymer is a polyphenylene derivative.
In some embodiments, the positive current collector includes, but is not limited to, a metal foil or a composite current collector. For example, aluminum foil may be used. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, or the like) on a polymer substrate.
2. Electrochemical device
One or more embodiments of the present application also provide an electrochemical device including the aforementioned positive electrode tab.
The electrochemical device of the application also comprises a negative electrode plate and electrolyte.
In some embodiments, the negative electrode tab includes a negative electrode current collector and a negative electrode active material. The negative electrode active material includes at least one material selected from a silicon-based material, a carbon-based material, a tin-based material, a phosphorus-based material, and metallic lithium. The silicon-based material includes at least one of silicon, a silicon alloy, a silicon oxygen compound, and a silicon carbon compound. The carbon-based material includes at least one of graphite, soft carbon, hard carbon, carbon nanotubes, and graphene. The tin-based material includes at least one of tin, tin oxide, and tin alloy. The negative electrode current collector includes: at least one of copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, or any combination thereof.
In some embodiments, the negative electrode tab further comprises a binder and a conductive agent. Binders include, but are not limited to: at least one of polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, an ethyleneoxy-containing polymer, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, or the like. Conductive agents include, but are not limited to: at least one of carbon-based materials, metal-based materials, conductive polymers, and mixtures thereof. In some embodiments, the carbon-based material comprises natural graphite, synthetic graphite, carbon black, acetylene black, ketjen black, carbon fiber, or any combination thereof. In some embodiments, the metal-based material comprises metal powder, metal fibers, copper, nickel, aluminum, or silver. In some embodiments, the conductive polymer includes a polyphenylene derivative.
The electrochemical device of the present application further comprises an electrolyte comprising a lithium salt and a nonaqueous solvent.
In some embodiments of the application, the lithium salt includes, but is not limited to, liPF 6 、LiBF 4 、LiAsF 6 、LiClO 4 、LiB(C 6 H 5 ) 4 、LiCH 3 SO 3 、LiCF 3 SO 3 、LiN(SO 2 CF 3 ) 2 、LiC(SO 2 CF 3 ) 3 、LiSiF 6 One or more of LiBOB or lithium difluoroborate.
Exemplary lithium salts may be LiPF 6 。
The nonaqueous solvent includes, but is not limited to, one or more of a carbonate compound, a carboxylate compound, or an ether compound.
Illustratively, the carbonate compounds include, but are not limited to, one or more of a chain carbonate compound or a cyclic carbonate compound. Specifically, the chain carbonate compounds include, but are not limited to, one or more of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), or methylethyl carbonate (MEC); the cyclic carbonate compounds include, but are not limited to, one or more of Ethylene Carbonate (EC), propylene Carbonate (PC), butylene Carbonate (BC), or Vinyl Ethylene Carbonate (VEC).
Exemplary carboxylate compounds include, but are not limited to, one or more of methyl formate, methyl acetate, ethyl acetate, n-propyl acetate, t-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, gamma-butyrolactone, decalactone, valerolactone, or caprolactone.
Exemplary ether compounds include, but are not limited to, one or more of dibutyl ether, tetraglyme, diglyme, 1, 2-dimethoxyethane, 1, 2-diethoxyethane, ethoxymethoxyethane, 2-methyltetrahydrofuran, or tetrahydrofuran.
In some embodiments, a separator is provided between the positive and negative electrode sheets to prevent shorting. The materials and shape of the separator that can be used in the embodiments of the present application are not particularly limited, and may be any of the techniques disclosed in the prior art. In some embodiments, the separator comprises a polymer or inorganic, etc., formed from a material that is stable to the electrolyte of the present application.
Electrochemical devices of the present application include, but are not limited to: all kinds of primary batteries, secondary batteries, fuel cells, solar cells or capacitors. In some embodiments, the electrochemical device is a lithium secondary battery. In some embodiments, lithium secondary batteries include, but are not limited to: lithium metal secondary batteries, lithium ion secondary batteries, lithium polymer secondary batteries, or lithium ion polymer secondary batteries.
In a specific example of the present application, the electrochemical device is a lithium ion battery, and the present application is not particularly limited to the type of lithium ion battery, and may be any type of lithium ion battery, such as button type, cylinder type, soft pack type lithium ion battery, and the like.
3. Power utilization device
One or more embodiments of the present application also provide an electric device including the aforementioned electrochemical device.
In some embodiments, the power utilization device of the present application includes, but is not limited to: notebook computers, pen-input computers, mobile computers, electronic book players, portable telephones, portable facsimile machines, portable copiers, portable printers, headsets, video recorders, liquid crystal televisions, hand-held cleaners, portable CD-players, mini-compact discs, transceivers, electronic notebooks, calculators, memory cards, portable audio recorders, radios, stand-by power supplies, motors, automobiles, motorcycles, mopeds, bicycles, lighting fixtures, toys, game machines, watches, electric tools, flash lamps, cameras, household large-sized batteries or lithium-ion capacitors, and the like.
Hereinafter, the electrochemical device of the present application will be further described with reference to specific examples and comparative examples.
Examples and comparative examples
Example 1
Preparing a positive electrode plate: positive electrode active material LiNi composed of primary particles m Co n Mn (1-m-n) O 2 Mixing a conductive agent LiTx300, a carbon nano tube and a binder PVDF according to a mass ratio of 97:1.5:0.5:1, adding a solvent NMP, and stirring under the action of a vacuum stirrer until the system is uniform to obtain positive electrode slurry; uniformly coating the anode slurry on an anode current collector, transferring to an oven for continuous drying, cold pressing, cutting and die cutting to obtain the anodePole pieces.
Preparing a negative electrode plate: mixing a negative electrode active substance (graphite and silica), a conductive agent SuperP, a thickening agent CMC and a binder SBR according to a mass ratio of 95.2:1.0:0.8:3.0, adding solvent deionized water, and stirring under the action of a vacuum stirrer until the system is uniform to obtain a negative electrode slurry; and uniformly coating the negative electrode slurry on a negative electrode current collector, transferring to an oven for continuous drying, and then carrying out cold pressing, slitting and die cutting to obtain a negative electrode plate.
Preparation of electrolyte: the electrolyte is Ethylene Carbonate (EC), propylene Carbonate (PC) and diethyl carbonate (DEC) according to the mass ratio of EC: PC: dec=1:1:1, followed by addition of lithium salt LiPF 6 And fluoroethylene carbonate, wherein the electrolyte is obtained after uniform mixing, and the LiPF is based on the mass of the electrolyte 6 The mass percentage of (2) is 14.5%, and the mass percentage of fluoroethylene carbonate is 3%.
A diaphragm: the separator was Polyethylene (PE) 9 μm thick.
Preparation of a lithium ion battery: and sequentially carrying out Z-shaped lamination on the positive pole piece, the isolating film and the negative pole piece in a lamination machine, enabling the isolating film to be positioned between the positive pole piece and the negative pole piece to play a role of isolation, placing the bare cell in the aluminum plastic film, and obtaining the lithium ion battery through the technological processes of liquid injection, formation, exhaust, aging, trimming and the like.
Examples 2 to 14
Examples 2 to 14 are different from example 1 in the crystal type of the positive electrode active material of the positive electrode sheet, median particle diameter Dv 50 The particle strength t, the miscibility factor I and the tortuosity s are shown in Table 1. Parameters in the design and manufacturing process of the lithium ion battery pole piece are controlled according to requirements, for example, the types and crystal forms of the positive electrode active materials, particle sizes, flow rates of slurry, rolling pressure, roll gap size and the like are changed, so that the parameters are controlled. The remaining preparation methods of examples 2 to 14 were the same as example 1.
Comparative examples 1 to 4
Comparative examples 1 to 4 are different from example 1 in the material type, crystal structure of the positive electrode active material of the positive electrode sheetMedian particle diameter Dv 50 The particle strength t, the miscibility factor I and the tortuosity s are shown in Table 1. Parameters in the design and manufacturing process of the lithium ion battery pole piece are controlled according to requirements, for example, the types and crystal forms of the positive electrode active materials, particle sizes, flow rates of slurry, rolling pressure, roll gap size and the like are changed, so that the parameters are controlled. The remaining preparation methods of comparative examples 1 to 4 were the same as in example 1.
The testing method comprises the following steps:
1. particle size testing:
and (3) ultrasonically dispersing the powder of the positive electrode active material by using ultrapure water as a dispersing agent, wherein the concentration is 15mg/ml, and adding sodium hexametaphosphate. The test is carried out by adopting a laser particle size analyzer, the refractive index of the material is set to be 1.692, and the refractive index of the dispersing agent is set to be 1.330.
2. Particle strength test:
and (3) drying the powder material in a vacuum drying oven at 110 ℃ for 12 hours, dipping a very small amount of powder to disperse the particles in a single layer, adopting a DUH-211/211S Shimadzu dynamic ultra-microhardness tester to test stress-displacement curve to obtain indentation hardness of 100 different particles, and taking an average value as a particle strength test value of the material.
3. X-ray diffraction test:
1g of positive electrode active material powder is placed in a sample tank to be flattened, an X-ray diffractometer is adopted for testing, the scanning range 2 theta is set to be 10 degrees to 80 degrees, and the scanning speed is set to be 2 degrees/min.
4. Tortuosity test
The tortuosity can be calculated by adopting a mode of combining an X-ray tomography/cross-section scanning electron microscope and simulation, and a fitting formula adopts tau=f epsilon -α Where f is the proportionality coefficient, ε is the porosity of the pole piece, and α is the Bruggeman index. The porosity of the pole piece is tested by a true density instrument and is tested by a helium gas compression method.
5. 2C specific discharge capacity test:
1) After standing for 30min, charging 1/3C CC-CV to 4.25V, and keeping the cut-off current at 0.05C; 2) Standing for 30min, and discharging the 2C to 2.5V; 3) Repeating the steps 6-7 for 3 times, and taking the gram capacity of the third discharge as the specific capacity of the discharge of 2C.
6. Cyclic capacity retention test:
1) Standing the lithium ion battery for 3 hours in the environment of 45 ℃ to reach temperature balance; 2) 1/3C discharge to 2.5V; 3) After standing for 30min, charging 1C CC-CV to 4.25V, and keeping the cut-off current at 0.05C; 4) Standing for 30min, and discharging 1C to 2.5V; 5) Repeating the steps 3-4 for 400 times, and taking the ratio of the 400 th discharge specific capacity to the 1 st discharge specific capacity as the high temperature circulation capacity retention rate.
Referring to table 1, as can be seen from any one of comparative examples 1 to 5 and any one of examples 1 to 10, the transmission coefficient F at the positive electrode sheet satisfies: when F is more than or equal to 70 and less than or equal to 130, the specific capacity of the lithium battery in 2C discharge and the retention rate of the cycling capacity after 500 circles at 45 ℃ are both obviously improved. The possible reason is that when the transmission coefficient F of the positive electrode sheet satisfies the above conditions, the lithium-nickel mixed discharging degree of the positive electrode active material itself, the pore channel structure of the positive electrode active material layer, the particle strength of the positive electrode active material and the specific surface area of the positive electrode active material realize overall optimization, are not easily crushed in the rolling stage, so that the structure of the positive electrode sheet of the lithium battery is very stable and can be fully infiltrated by electrolyte, the transmission of lithium ions in the circulation process is smooth and can reach balance, the conductivity of the positive electrode sheet is improved, the impedance is reduced, and further the improvement of the multiplying power performance is realized.
It can be seen that the tortuosity s of the positive electrode active material layer, the particle strength t of the positive electrode active material, the mixing factor I of the positive electrode active material, and the median particle diameter Dv of the positive electrode active material 50 The four have obvious synergistic effect.
While certain exemplary embodiments of the application have been illustrated and described, the application is not limited to the disclosed embodiments. Rather, one of ordinary skill in the art will recognize that certain modifications and changes may be made to the described embodiments without departing from the spirit and scope of the present application as described in the appended claims.

Claims (10)

1. The positive pole piece is characterized by comprising a positive current collector and a positive active material layer positioned on the surface of the positive current collector, wherein the transmission coefficient F of the positive pole piece meets the following conditions: f is more than or equal to 70 and less than or equal to 130,
，
wherein I is a shuffling factor, i=i (003) /I (104) ，I (003) A peak intensity of a (003) -plane diffraction peak in an X-ray diffraction pattern of the positive electrode active material in the positive electrode active material layer, I (104) Peak intensity of (104) plane diffraction peak;
t is the particle strength of the positive electrode active material, and the unit is MPa;
s is the tortuosity of the positive pole piece;
Dv 50 the median particle size of the positive electrode active material based on volume standard is in [ mu ] m;
the positive electrode plate also satisfies the following conditions:
(a) The shuffling factor I is 1.5 to 2.5;
(b) The particle strength t of the positive electrode active material is 120 MPa to 300 MPa;
(c) The tortuosity s of the positive pole piece is 1.2 to 4.0;
(d) Median particle diameter Dv of the positive electrode active material 50 0.5 μm to 7 μm;
the positive electrode active material includes at least one of nickel-cobalt-based materials.
2. The positive electrode sheet according to claim 1, wherein the transmission coefficient F of the positive electrode sheet further satisfies: f is more than or equal to 80 and less than or equal to 120.
3. The positive electrode sheet according to claim 1, wherein at least one of the following conditions is also satisfied:
(e) The shuffling factor I is 1.7 to 2.4;
(f) The particle strength H of the positive electrode active material is 150 MPa to 270 MPa;
(g) The tortuosity s of the positive pole piece is 1.8 to 3.0;
(h) Median particle diameter Dv of the positive electrode active material 50 1.5 μm to 5 μm.
4. The positive electrode sheet according to any one of claims 1 to 3, characterized in that at least one of the following conditions is also satisfied:
(i) The surface density m of the positive electrode plate meets the following conditions: 40 mg/cm 2 ≤m≤65 mg/cm 2 ；
(j) The average thickness h of the positive electrode active material layer satisfies: 112. and h is less than or equal to 156 mu m.
5. The positive electrode sheet according to any one of claims 1 to 3, wherein the positive electrode active material includes at least one of primary particles and secondary particles.
6. The positive electrode sheet according to any one of claims 1 to 3, wherein the positive electrode active material comprises at least one of nickel-cobalt-based ternary materials;
the nickel-cobalt ternary material comprises Li a Ni m Co n A (1-m-n) O 2 At least one of the materials, wherein A comprises at least one of manganese, aluminum, magnesium, chromium, calcium, zirconium, molybdenum, silver or niobium, a is more than or equal to 0.9 and less than or equal to 1.2,0.5 and less than or equal to m and less than or equal to 1, n is more than or equal to 0 and less than or equal to 0.5, and m+n is more than or equal to 1.
7. The positive electrode sheet according to claim 6, wherein the positive electrode active material comprises at least one of lithium nickel oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium nickel manganese cobalt magnesium oxide, and lithium nickel manganese oxide.
8. The positive electrode sheet according to any one of claims 1 to 3, wherein the positive electrode active material layer further comprises a binder and a conductive agent, the mass ratio of the positive electrode active material, the binder and the conductive agent satisfying: (90-98): 1-5.
9. An electrochemical device comprising the positive electrode sheet according to any one of claims 1 to 8.
10. An electrical device comprising the electrochemical device of claim 9.
CN202310737675.3A 2023-06-19 2023-06-19 Positive electrode sheet, electrochemical device, and electricity consumption device Active CN116504921B (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09245836A (en) * 1996-03-08 1997-09-19 Fuji Photo Film Co Ltd Nonaqueous electrolyte secondary battery
JP2008243447A (en) * 2007-03-26 2008-10-09 Mitsubishi Chemicals Corp Lithium transition metal composite oxide, its manufacturing method, cathode for lithium secondary battery using it, and lithium secondary battery using it
CN111247668A (en) * 2017-07-28 2020-06-05 美商映能量公司 Electrode with interface structure
CN113437288A (en) * 2021-06-29 2021-09-24 贝特瑞（江苏）新材料科技有限公司 Positive electrode active material, preparation method thereof and lithium ion battery

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7374339B2 (en) * 2021-02-23 2023-11-06 エルジー エナジー ソリューション リミテッド Sacrificial cathode material with reduced gas generation and method for manufacturing the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09245836A (en) * 1996-03-08 1997-09-19 Fuji Photo Film Co Ltd Nonaqueous electrolyte secondary battery
JP2008243447A (en) * 2007-03-26 2008-10-09 Mitsubishi Chemicals Corp Lithium transition metal composite oxide, its manufacturing method, cathode for lithium secondary battery using it, and lithium secondary battery using it
CN111247668A (en) * 2017-07-28 2020-06-05 美商映能量公司 Electrode with interface structure
CN113437288A (en) * 2021-06-29 2021-09-24 贝特瑞（江苏）新材料科技有限公司 Positive electrode active material, preparation method thereof and lithium ion battery

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