CN117525433A - Current collector, positive plate and battery - Google Patents

Current collector, positive plate and battery Download PDF

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Publication number
CN117525433A
CN117525433A CN202311513448.9A CN202311513448A CN117525433A CN 117525433 A CN117525433 A CN 117525433A CN 202311513448 A CN202311513448 A CN 202311513448A CN 117525433 A CN117525433 A CN 117525433A
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CN
China
Prior art keywords
positive electrode
coating
current collector
ltoreq
lithium
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202311513448.9A
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Chinese (zh)
Inventor
王昊鹏
赵伟
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Zhuhai Cosmx Battery Co Ltd
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Zhuhai Cosmx Battery Co Ltd
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Priority to CN202311513448.9A priority Critical patent/CN117525433A/en
Publication of CN117525433A publication Critical patent/CN117525433A/en
Pending legal-status Critical Current

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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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. coatings
    • 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
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/663—Selection of materials containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
    • 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 invention relates to the field of batteries, in particular to a current collector, a positive plate comprising the current collector and a battery comprising the current collector. The current collector comprises a substrate layer and a coating layer on at least one side surface of the substrate layer; the XRD diffraction pattern of the coating has diffraction peaks at 42.8 degrees-2 theta-44 degrees and 44 degrees-2 theta-45.2 degrees; the coating contains the following elements: fe. O and C. The outer surface of the current collector is provided with the coating, and the coating has a stable structure and can improve the needling test passing rate of the battery.

Description

Current collector, positive plate and battery
Technical Field
The invention relates to the field of batteries, in particular to a current collector, a positive plate comprising the current collector and a battery comprising the current collector.
Background
In recent years, with rapid development of portable electronic devices, electric vehicles, and power grid energy storage technologies, there is an increasing demand for batteries having high energy density, long life, and excellent rate performance. In view of the above requirements, lithium ion batteries are currently the most desirable energy storage devices. Typically, the battery passes through a needling test less frequently.
Therefore, it is important to invent a battery with superior needling test pass rate.
Disclosure of Invention
The present invention has been made to overcome the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a current collector, a positive electrode tab including the current collector, and a battery including the current collector. The outer surface of the current collector is provided with the coating, and the coating has a stable structure and can improve the needling test passing rate of the battery.
The present invention provides in a first aspect a current collector comprising a substrate layer and a coating on at least one side surface of the substrate layer; the XRD diffraction pattern of the coating has diffraction peaks at 42.8 degrees-2 theta-44 degrees and 44 degrees-2 theta-45.2 degrees; the coating contains the following elements: fe. O and C.
The second aspect of the invention provides a positive plate comprising the current collector according to the first aspect of the invention.
A third aspect of the present invention provides a battery comprising the current collector according to the first aspect of the present invention and/or the positive electrode sheet according to the second aspect of the present invention.
Through the technical scheme, compared with the prior art, the invention has at least the following advantages:
(1) The XRD diffraction pattern of the coating has diffraction peaks in a specific angle range, so that the coating has a stable structure, and the safety performance of the current collector can be improved, thereby improving the needling test passing rate of the battery;
(2) The battery of the present invention has excellent cycle capacity retention.
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
Drawings
Figure 1 shows the XRD diffraction pattern of a coating in an example of the invention.
Fig. 2 shows a Scanning Electron Microscope (SEM) image and an energy spectrometer (EDS) test image of a coating in an example of the invention.
Figure 3 shows the XRD diffractogram of the additive in an example of the invention.
Fig. 4 is a schematic cross-sectional view of a current collector according to an embodiment of the present invention.
Figure 5 shows the XRD diffractograms of the coatings of examples 1, 4a, 4b and 4c of the present invention.
Detailed Description
The following describes specific embodiments of the present invention in detail. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
The present invention provides, in a first aspect, a current collector that may include a base layer and a coating layer on at least one side surface of the base layer; the XRD diffraction pattern of the coating has diffraction peaks at 42.8 DEG-2 theta-44 DEG and 44 DEG-2 theta-45.2 deg. In the present invention, the "having diffraction peaks at 42.8. Ltoreq. 2θ. Ltoreq.44℃and 44. Ltoreq. 2θ. Ltoreq.45.2℃" has the conventional meaning in the art, meaning that the angles of the diffraction peaks corresponding to the peaks are in the range of 42.8. Ltoreq. 2θ. Ltoreq.44℃and 44. Ltoreq. 2θ < 45.2 ℃. As shown in FIG. 1, which shows the XRD diffraction patterns of the coating in an example of the present invention, it can be seen that the coating has diffraction peaks at 42.8.ltoreq.2θ.ltoreq.44℃and 44℃ <2θ.ltoreq.45.2 ℃.
In the present invention, the coating may contain the following elements: fe. O and C.
In the present invention, "the coating contains the following elements: fe. O and C "refer to: the coating was subjected to an energy spectrometer (EDS) test and at an acceleration voltage of 15kV the coating was detected to contain the following elements: fe. O and C. Fig. 2 shows a Scanning Electron Microscope (SEM) image and an energy spectrometer (EDS) test image of a coating according to an example of the present invention, from which it can be seen that the coating contains the elements Fe, O and C.
The inventors of the present invention found that when the diffraction peak of the XRD diffraction pattern of the coating layer is within a specific angle range, the coating layer has a relatively stable microstructure and weak oxidizing property, and can reduce oxidative decomposition of the electrolyte during the charge-discharge cycle of the battery, particularly under the high temperature condition of the needling test, the reduction of the oxidative decomposition of the electrolyte is particularly remarkable; and the coating comprises the element C, has good electron conductivity, and can reduce adverse effects on the internal resistance of the battery. Through a great deal of researches, the inventor of the invention discovers that when the coating is arranged on the outer surface of the substrate layer, the coating can protect the substrate layer, reduce the probability of short circuit occurrence between the current collector and the active material layer, reduce the probability of direct contact between the substrate layer and the metal nails in the needling test process, and remarkably improve the passing rate of the needling test of the battery.
In one example, the XRD diffraction pattern of the coating has diffraction peaks at 43 DEG.ltoreq.2θ.ltoreq.43.9 DEG and 44.2 DEG.ltoreq.2θ.ltoreq.45.1.
In one example, the XRD diffraction pattern of the coating has diffraction peaks at 43.2 DEG.ltoreq.2θ.ltoreq.43.5 DEG and 44.5 DEG.ltoreq.2θ.ltoreq.44.9 ℃.
In the present invention, the base layer may include a polymer layer and conductive layers on opposite side surfaces of the polymer layer. The base layer may further include a conductive layer. Fig. 4 is a schematic cross-sectional view of a current collector according to an embodiment of the present invention, wherein fig. 4 (a) is a case where the base layer includes a polymer layer and a conductive layer, and fig. 4 (b) is a case where the base layer includes a conductive layer. In fig. 4 (a), the current collector includes a base layer 1 and a coating layer 2 on both side surfaces of the base layer 1, wherein the base layer 1 includes a polymer layer 11 and conductive layers 12 on both side surfaces of the polymer layer 11; in fig. 4 (b), the current collector includes a base layer 1 and a coating layer 2 on both side surfaces of the base layer 1, wherein the base layer 1 includes a conductive layer 12.
In the present invention, the polymer layer may include at least one of polyoxymethylene, polyethylene, polyvinylmethylether, polyvinylethylether, a copolymer of ethylene and propylene, polyvinyl alcohol, polyvinyl acetate, polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polyvinyl chloride, polyvinylidene chloride, polypropylene, polyacrylic acid, polymethyl methacrylate, polyethyl acrylate, poly (α -nitrilylacrylate), polyacrylonitrile, polyisobutenyl rubber, neoprene, natural rubber, ancient tower rubber, styrene butadiene rubber, polydecylene formamide, polyhexamethylene adipamide, polyhexamethylene sebacamide, polyethylene terephthalate, polyethylene oxide, polyphenylene sulfide, poly [ bis (trifluoroethoxy) phosphazene ], polydimethylsiloxane, polyvinylcarbazole, polytetrafluoroethylene, polyacrylamide, polyethylene terephthalate, polybutylene terephthalate, and polycarbonate.
In one example, the polymer comprises polyethylene terephthalate.
The inventors of the present invention have found that when the base layer comprises a polymer layer, it is able to withstand a certain degree of deformation during its preparation and use without causing fracture damage, and that the polymer layer is also able to further improve the needling test pass rate of the battery.
In the present invention, the conductive layer may include metallic aluminum or an aluminum alloy.
In the present invention, the coating may include an additive. The XRD diffraction pattern of the additive has diffraction peaks at 42.8 degrees-2 theta-44 degrees and 44 degrees-2 theta-45.2 degrees. As shown in FIG. 3, which shows XRD diffraction patterns of the additive in an example of the present invention, it can be seen that the additive has diffraction peaks at 42.8.ltoreq.2θ.ltoreq.44℃and 44.ltoreq.2θ.ltoreq.45.2 ℃.
In one example, the XRD diffraction pattern of the additive has diffraction peaks at 43 DEG.ltoreq.2θ.ltoreq.43.9 DEG and 44.2 DEG.ltoreq.2θ.ltoreq.45.1.
In one example, the XRD diffraction pattern of the additive has diffraction peaks at 43.2 DEG.ltoreq.2θ.ltoreq.43.5 DEG and 44.5 DEG.ltoreq.2θ.ltoreq.44.9 ℃.
The inventors of the present invention have found that when the XRD diffraction pattern of the additive has diffraction peaks at specific angles, the additive has a relatively stable microstructure and weak oxidizing property during charge and discharge cycles of the battery, and can reduce oxidative decomposition of the electrolyte, particularly under the high temperature condition of the needling test.
In the present invention, the additive may include a substance represented by formula I, the surface of which may be further coated with a material containing element C,
Li x Fe y-a M a O z I，
wherein M comprises at least one of Al, mg, ti and Zr, 0.ltoreq.x.ltoreq.1 (e.g., 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1), y is 1, 2 or 3, 0.ltoreq.a.ltoreq.0.3 (e.g., 0, 0.1, 0.2 or 0.3), 1.ltoreq.z.ltoreq.4 (e.g., 1, 1.5, 2, 2.5, 3, 3.5 or 4), satisfying: x/z.ltoreq.0.5 (e.g.0, 0.1, 0.2, 0.3, 0.4 or 0.5) and y/z.ltoreq.1 (e.g.0.25, 0.5 or 1).
The inventors of the present invention found that when the additive includes a substance represented by formula I, and when a, x, y, and z satisfy specific conditions, a lithium source can be additionally provided during charge and discharge cycles of the battery, which is advantageous in improving the cycle capacity retention rate of the battery; in addition, the additive has a stable structure, which is beneficial to improving the cycle capacity retention rate of the battery; the material containing the element C is coated on the surface of the substance shown in the chemical formula I, so that the coating has good conductivity, and adverse effects of the additive on the internal resistance of the battery can be reduced; the additive can also enhance the bonding performance between the current collector and the active material layer, improve the conduction performance between the current collector and the active material layer, improve the peeling strength, and avoid the delithiation of the active material layer in the charge-discharge cycle of the battery, thereby further improving the safety performance.
In one example, x is 0 or 1.
In one example, z is 2-4.
In one example, x/z is 0 or 0.5.
In one example, 0.5.ltoreq.y/z.ltoreq.1.
In the present invention, the "coating" may be a complete coating or a partial coating.
In the present invention, in the XRD diffraction pattern of the coating layer, the intensity of the diffraction peak at 44 DEG <2 theta < 45.2 DEG is equal to or more than the intensity of the diffraction peak at 42.8 DEG <2 theta < 44 deg.
In one example, in the XRD diffraction pattern of the coating, the intensity of the diffraction peak at 44 <2 theta +.45.2 deg. is greater than the intensity of the diffraction peak at 42.8 <2 theta +.44 deg..
In the present invention, in the XRD diffraction pattern of the coating layer, the intensity of the diffraction peak at 44.2 DEG.ltoreq.2θ.ltoreq.45.1 DEG is equal to or greater than the intensity of the diffraction peak at 43 DEG.ltoreq.2θ.ltoreq.43.9 deg.
In one example, in the XRD diffraction pattern of the coating, the intensity of the diffraction peak at 44.2. Ltoreq. 2θ.ltoreq.45.1℃is greater than the intensity of the diffraction peak at 43. Ltoreq. 2θ.ltoreq.43.9 ℃.
In the present invention, in the XRD diffraction pattern of the coating layer, the intensity of the diffraction peak at 44.5 DEG.ltoreq.2θ.ltoreq.44.9 DEG is equal to or more than the intensity of the diffraction peak at 43.2 DEG.ltoreq.2θ.ltoreq.43.5 deg.
In one example, in the XRD diffraction pattern of the coating, the intensity of the diffraction peak at 44.5 <2 > theta < 44.9 deg. is greater than the intensity of the diffraction peak at 43.2 <2 > theta < 43.5 deg..
In the present invention, in the XRD diffraction pattern of the additive, the intensity I2 of the diffraction peak at 44 DEG <2 theta < 45.2 DEG is equal to or more than the intensity I1 of the diffraction peak at 42.8 DEG <2 theta < 44 deg.
In one example, in the XRD diffraction pattern of the additive, the intensity I2 of the diffraction peak at 44 <2 theta +.45.2 DEG is greater than the intensity I1 of the diffraction peak at 42.8 <2 theta +.44 deg.
In the present invention 1< I2/I1<2, e.g. I2/I1 equals 1.01, 1.05, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 1.95 or 1.99.
In one example, 1.5< I2/I1<2.
The inventor of the invention discovers that when the I2/I1 is in a specific range, the additive has a more stable crystal structure, which is beneficial to improving the structural stability of the coating and the current collector, thereby playing a more effective role in protecting the substrate layer, reducing the probability of short circuit between the current collector and the active material layer, reducing the probability of direct contact between the substrate layer and the metal nails in the needling test process, and being beneficial to improving the needling test passing rate of the battery.
In the present invention, in the XRD diffraction pattern of the additive, the intensity of the diffraction peak at 44.2 DEG.ltoreq.2θ.ltoreq.45.1 DEG is equal to or greater than the intensity of the diffraction peak at 43 DEG.ltoreq.2θ.ltoreq.43.9 deg.
In one example, in the XRD diffraction pattern of the additive, the intensity of the diffraction peak at 44.2. Ltoreq. 2θ.ltoreq.45.1℃is greater than the intensity of the diffraction peak at 43. Ltoreq. 2θ.ltoreq.43.9 ℃.
In the present invention, in the XRD diffraction pattern of the additive, the intensity of the diffraction peak at 44.5 DEG.ltoreq.2θ.ltoreq.44.9 DEG is equal to or greater than the intensity of the diffraction peak at 43.2 DEG.ltoreq.2θ.ltoreq.43.5 deg.
In one example, in the XRD diffraction pattern of the additive, the intensity of the diffraction peak at 44.5.ltoreq.2θ.ltoreq.44.9℃is greater than the intensity of the diffraction peak at 43.2.ltoreq.2θ.ltoreq.43.5 ℃.
The inventors of the present invention found that when the diffraction peak of the XRD diffraction pattern of the additive is within a specific angle range, the additive has a relatively stable microstructure and weak oxidizing property, and can reduce oxidative decomposition of the electrolyte and increase protection of the base layer under high temperature conditions of the needling test during charge and discharge cycles of the battery.
In the present invention, the thickness of the coating layer may be 0.1 μm to 20 μm, for example 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm.
In one example, the thickness of the coating is 2 μm to 4 μm.
In the present invention, the thickness of the coating refers to the single layer thickness of the coating; the thickness of the coating may be measured using methods conventional in the art, for example, by Scanning Electron Microscopy (SEM), a cross-sectional view of the current collector may be obtained, and the thickness of the coating may be measured from 10 points randomly selected from the graph, and averaged.
In the present invention, the substance represented by formula I may include LiFeO 2 、Fe 3 O 4 、Fe 2 O 3 And LiFe 0.8 Al 0.2 O 2 At least one of them.
The inventor of the present invention found that when the substance represented by the chemical formula I includes a specific substance, the coating has a stable structure, can be kept stable in a high-potential environment, and particularly can be kept stable under the dual effects of high temperature and high potential, and is not easy to undergo side reaction with the electrolyte; further, when the substance represented by formula I includes elemental Li, li may be also extracted during the battery charging process, thereby playing a role in lithium supplementation.
In one example, the material of formula I comprises LiFeO 2 。
In one example, the material of formula I comprises LiFeO 2 With Fe 2 O 3 Is a mixture of (a) and (b).
In one example, the material of formula I comprises LiFeO 2 With Fe 2 O 3 Wherein LiFeO 2 With Fe 2 O 3 The mass ratio of ∈1:1 (e.g., 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1).
In one example, the material of formula I comprises LiFeO 2 With Fe 3 O 4 Is a mixture of (a) and (b).
In one example, the material of formula I comprises LiFeO 2 With Fe 3 O 4 Wherein LiFeO 2 With Fe 3 O 4 The mass ratio of ∈1:1 (e.g., 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1).
The inventors of the present invention found that when the substance of formula I comprises LiFeO 2 With Fe 2 O 3 Is a mixture of (B) and (C) LiFeO 2 With Fe 3 O 4 And Li can be removed in the charging process of the battery, so that the lithium supplementing effect is achieved, and the electrochemical performance of the battery is improved.
In the present invention, the material containing the element C may be a carbon material having electron conductivity.
In one example, the material containing element C comprises a carbon material. The carbon material may include at least one of hard carbon, soft carbon, carbon black, conductive graphite, carbon nanotubes, and graphene.
In one example, the carbon material comprises soft carbon.
In one example, the carbon material comprises hard carbon.
The inventors of the present invention have found that a specific carbon material can enhance the conductivity of the additive, strengthen the conductive connection between the coating and the positive electrode active material layer, and facilitate the extraction of lithium ions in the additive.
In the present invention, in the additive, the ratio of the mass of the element Fe to the mass of the element C may be (5-30): 1, for example 5:1. 10:1. 15:1. 20:1. 25:1 or 30:1.
in one example, in the additive, the ratio of the mass of element Fe to the mass of element C is (10-20): 1.
in the present invention, the additive may be present in an amount of 20 to 99 wt%, for example 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 99 wt%, based on the total weight of the coating.
In one example, the additive is present in an amount of 50 to 80 weight percent, based on the total weight of the coating.
In the present invention, the coating layer may further include a first conductive agent and a first binder. The first conductive agent may include at least one of conductive carbon black, acetylene black, ketjen black, conductive graphite, carbon nanotubes, and carbon fibers. The first binder may include at least one of polyvinylidene fluoride, polytetrafluoroethylene, and polyethylene oxide.
In the present invention, the additive may be contained in an amount of 20 to 99 wt% (e.g., 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 99 wt%), the first conductive agent may be contained in an amount of 0 to 40 wt% (e.g., 40, 35, 30, 25, 20, 15, 10, 5, 1, 0.5, 0.1, or 0 wt%), and the first binder may be contained in an amount of 1 to 40 wt% (e.g., 40, 35, 30, 25, 20, 15, 10, 5, or 1 wt%), based on the total weight of the coating layer.
In one example, the additive is present in an amount of 50 to 80 wt%, the first conductive agent is present in an amount of 2 to 15 wt%, and the first binder is present in an amount of 5 to 48 wt%, based on the total weight of the coating.
In the present invention, the thickness of the current collector may be 8 μm to 25 μm, for example, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm or 25 μm.
In one example, the current collector has a thickness of 12 μm to 18 μm.
The second aspect of the present invention provides a positive electrode sheet, which may include the current collector according to the first aspect of the present invention.
Generally, there are four short circuits inside the battery, namely, a contact short circuit between the positive electrode current collector and the negative electrode active material layer, a contact short circuit between the positive electrode current collector and the negative electrode current collector, a contact short circuit between the positive electrode active material layer and the negative electrode current collector, and a contact short circuit between the positive electrode active material layer and the negative electrode active material layer, wherein the contact short circuit between the positive electrode current collector and the negative electrode active material layer is most dangerous, and a large amount of heat can be generated instantaneously, so that thermal runaway of the battery can be rapidly induced. The inventors of the present invention have found that the use of the current collector according to the first aspect of the present invention as a positive electrode current collector can reduce the probability of the most dangerous short circuit, i.e., the contact short circuit between the positive electrode current collector and the negative electrode active material layer, and improve the penetration rate of the needling test of the battery.
In the present invention, the positive electrode sheet includes the current collector and a positive electrode active material layer on at least one side surface of the current collector. The positive electrode active material layer may include a positive electrode active material. The positive electrode active material may include at least one of the following: lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium nickel cobalt manganese aluminate, lithium manganate, lithium nickel manganate, lithium nickelate, lithium iron phosphate, lithium iron manganese phosphate, lithium vanadium phosphate and lithium-rich manganese.
In the present invention, the positive electrode active material may be a positive electrode active material subjected to doping and/or coating modification treatment, or may be a positive electrode active material not subjected to doping and coating modification treatment.
In one example, the positive electrode active material includes lithium cobaltate. The lithium cobalt oxide may be doped and/or coated lithium cobalt oxide; undoped and uncoated lithium cobalt oxide are also possible.
The ratio of the mass of the element Co in the positive electrode active material to the mass of the element Fe in the additive is more than or equal to 10:1, for example 10:1. 15:1. 20:1. 25: 1. 30:1. 35: 1. 40: 1. 45:
1. 50: 1. 55: 1. 60:1. 65: 1. 70: 1. 75: 1. 80: 1. 85: 1. 90: 1. 95: and (2) 100: 1. 110: 1. 120: 1. 130: 1. 140: 1. 150: 1. 160:1. 170: 1. 180: 1. 190: 1. 200: 1. 210: 1. 220: 1. 230: 1. 240: 1. 250: 1. 260: 1. 270: 1. 280: 1. 290:1 or 300:1.
the inventors of the present invention found that, when the ratio of the mass of the element Co in the positive electrode active material to the mass of the element Fe in the additive is within a specific range, the battery including the positive electrode sheet can improve the penetration rate of the needling test while ensuring the energy density.
In one example, the ratio of the mass of the element Co in the positive electrode active material to the mass of the element Fe in the additive is (20-80): 1.
in the present invention, the median particle diameter Dv50 of the positive electrode active material is 20 μm or less, for example, 20 μm, 19 μm, 18 μm, 17 μm, 16 μm, 15 μm, 14 μm, 13 μm, 12 μm, 11 μm, 10 μm, 9 μm, 8 μm, 7 μm, 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm or 0.5 μm.
The inventors of the present invention found that when the median particle diameter Dv50 of the positive electrode active material is >20 μm, rolling of the positive electrode sheet is not favored, and therefore, dv50 is not more than 20 μm, and breakage or falling off of the positive electrode active material during rolling can be avoided.
In the present invention, the ratio of the thickness of the positive electrode active material layer to the thickness of the coating layer may be (3 to 160): 1, for example 3:1. 5:1. 10:1. 20:1. 30:1. 40: 1. 50: 1. 60:1. 70: 1. 80: 1. 90: 1. 100: 1. 110: 1. 120: 1. 130: 1. 140:
1. 150:1 or 160:1.
the inventors of the present invention have found that, when the ratio of the thickness of the positive electrode active material layer to the thickness of the coating layer is within a specific range, a battery including the positive electrode sheet can improve the penetration rate of the needling test while ensuring the energy density.
In one example, the ratio of the thickness of the positive electrode active material layer to the thickness of the coating layer is (5-80): 1.
in one example, the ratio of the thickness of the positive electrode active material layer to the thickness of the coating layer is (7-30): 1.
in the present invention, the thickness of the positive electrode active material layer may be 15 μm to 80 μm, for example, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm or 80 μm.
In one example, the positive electrode active material layer has a thickness of 30 μm to 60 μm.
In the present invention, the thickness of the positive electrode active material layer refers to the thickness of the positive electrode active material layer on the positive electrode current collector side; the thickness of the positive electrode active material layer can be measured by a method conventional in the art, for example, a Scanning Electron Microscope (SEM) can be used to obtain a cross-sectional mirror image of the positive electrode sheet, and 10 points are randomly selected from the image to measure the thickness of the coating, and the average value is obtained.
In the present invention, the positive electrode active material layer may further include a second conductive agent and a second binder. The second conductive agent may include at least one of conductive carbon black, acetylene black, ketjen black, conductive graphite, carbon nanotubes, and carbon fibers. The second binder may include at least one of polyvinylidene fluoride, polytetrafluoroethylene, and polyethylene oxide.
In the present invention, the content of the positive electrode active material may be 80 to 99.8 wt% (e.g., 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 99.8 wt%), the content of the second conductive agent may be 0.1 to 10 wt% (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, or 0.1 wt%), and the content of the second binder may be 0.1 to 10 wt% (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, or 0.1%) based on the total weight of the positive electrode active material layer.
In one example, the positive electrode active material layer may contain 94 to 99 wt% of the positive electrode active material layer, 0.5 to 3 wt% of the second conductive agent, and 0.5 to 3 wt% of the second binder.
In the present invention, the positive electrode sheet may be prepared according to a method conventional in the art, for example: and uniformly dispersing the positive electrode active material, the second conductive agent and the second binder in a solvent to form positive electrode slurry, coating the positive electrode slurry on the current collector of the first aspect of the invention, and drying to obtain the positive electrode plate. The solvent may be selected from solvents conventionally used in the art, for example, N-methylpyrrolidone.
A third aspect of the present invention provides a battery comprising the current collector according to the first aspect of the present invention and/or the positive electrode sheet according to the second aspect of the present invention.
Components of the battery other than the positive electrode sheet (e.g., a negative electrode sheet, a separator, and an electrolyte, etc.) may be conventional choices in the art.
In one example, the battery further includes a negative electrode sheet, a separator, and an electrolyte.
The negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer on at least one side surface of the negative electrode current collector. The anode active material layer may include an anode active material, an anode conductive agent, and an anode binder.
The negative electrode active material may be a conventional choice in the art, for example, the negative electrode active material includes at least one of artificial graphite, natural graphite, mesophase carbon microspheres, hard carbon, soft carbon, metallic lithium, silicon oxide, and silicon carbon. The negative electrode conductive agent may include one or more of conductive carbon black, acetylene black, ketjen black, conductive graphite, carbon nanotubes, metal powder, and carbon fibers. The negative electrode binder may include at least one or more of sodium carboxymethyl cellulose, styrene-butadiene rubber, polytetrafluoroethylene, and polyethylene oxide.
In the present invention, the negative electrode active material may be contained in an amount of 80 to 99.8 wt% (e.g., 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 99.8 wt%), the negative electrode conductive agent may be contained in an amount of 0.1 to 10 wt% (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5 or 0.1 wt%), and the negative electrode binder may be contained in an amount of 0.1 to 10 wt% (e.g., 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5 or 0.1 wt%), based on the total weight of the negative electrode coating layer.
In one example, the negative electrode active material is contained in an amount of 90 to 99.6 wt%, the negative electrode conductive agent is contained in an amount of 0.2 to 5 wt%, and the negative electrode binder is contained in an amount of 0.2 to 5 wt%, based on the total weight of the negative electrode coating layer.
In the present invention, the negative electrode sheet may be prepared according to a method conventional in the art, for example: and uniformly dispersing the anode active material, the anode conductive agent and the anode binder in an anode solvent to form anode slurry, coating the anode slurry on an anode current collector, and drying to obtain the anode sheet. The negative electrode solvent may be selected from solvents conventionally used in the art, for example, deionized water.
In the present invention, the separator may be selected from at least one of separators conventionally used in the art, such as a polyethylene film or a polypropylene film.
In the present invention, the electrolyte may be selected from electrolytes conventionally used in the art, for example, the electrolyte includes an organic solvent and an electrolyte salt. The organic solvent may include Ethylene Carbonate (EC), propylene Carbonate (PC), butylene Carbonate (BC), dimethyl carbonate fluoride, ethyl methyl carbonate fluoride, ethylene Propylene Carbonate (EPC), dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, methyl ethyl carbonate (EMC), methyl Propyl Carbonate (MPC), methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl Acetate (EA), propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, methyl butyrate, butyl butyrateAt least one of ethyl acetate, propyl butyrate, butyl butyrate, methyl difluoroacetate, ethyl difluoroacetate, gamma-butyrolactone (GBL), gamma-valerolactone, delta-valerolactone, ethylene glycol dimethyl ether (DME), 1, 3-Dioxane (DOL), 1, 4-Dioxane (DOX), sulfolane, dimethyl sulfoxide (DMSO), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), methylene chloride and ethylene dichloride. The electrolyte salt may include lithium hexafluorophosphate (LiPF) 6 ) Lithium tetrafluoroborate (LiBF) 4 ) Lithium perchlorate (LiClO) 4 ) Lithium hexafluoroarsenate (LiAsF) 6 ) Lithium hexafluoroantimonate (LiSbF) 6 ) Lithium difluorophosphate (LiPF) 2 O 2 ) At least one of lithium 4, 5-dicyano-2-trifluoromethylimidazole (LiDTI), lithium bis (oxalato) borate (LiBOB), lithium bis (malonato) borate (LiBMB), lithium difluoro (oxalato) borate (LiDFOB), lithium bis (difluoromalonato) borate (LiBDFMB), (malonato) borate (LiMOB), lithium bis (fluorosulfonyl) imide (LiSI) and lithium bis (trifluoromethylsulfonyl) imide (LiTFSI).
The battery may be assembled in a manner conventional in the art. For example, stacking or winding the positive electrode sheet, the separator and the negative electrode sheet in sequence to obtain a battery cell; and placing the battery cell in a packaging shell, injecting the electrolyte and sealing to obtain the battery.
In the present invention, the numerical expressions "first", "second", and the like are used only to distinguish different substances or modes of use, and do not represent differences in order.
The present invention will be described in detail by examples. The described embodiments of the invention are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
The battery was prepared according to the following steps:
(1) Preparation of current collector
The additive (LiFeO) 2 Surface-coated soft carbon, wherein the elementThe mass ratio of element Fe to element C is about 15: 1) Mixing conductive carbon black and polyvinylidene fluoride according to the mass ratio of 75:5:20, adding N-methyl pyrrolidone, stirring uniformly to obtain coating slurry, wherein the solid content is 70%, coating the coating slurry on the surfaces of two sides of an aluminum foil (the thickness is 9 mu m), and drying to obtain a current collector, wherein the thickness of the coating is about 4 mu m.
(2) Preparation of positive electrode sheet
Mixing lithium cobaltate (Dv 50 is 15 mu m), conductive carbon black and polyvinylidene fluoride according to the mass ratio of 97:1:2, adding N-methyl pyrrolidone, stirring uniformly to obtain positive electrode slurry, wherein the solid content is 70%, uniformly coating the positive electrode slurry on the current collector obtained in the step (1), drying, rolling and cutting to obtain a positive electrode plate, wherein the thickness of a positive electrode active material layer is 30 mu m, and the mass ratio of element Co in lithium cobaltate to the mass ratio of element Fe in an additive is about 21:1.
(3) Preparation of negative electrode sheet
Mixing artificial graphite, conductive carbon black and sodium carboxymethylcellulose according to the mass ratio of 96:1:3, adding deionized water, stirring uniformly to obtain negative electrode slurry, wherein the solid content is 45%, uniformly coating the negative electrode slurry on copper foil (the thickness is 6 mu m), and drying, rolling and cutting to obtain a negative electrode sheet.
(4) Preparation of a cell
Sequentially laminating the positive plate prepared in the step (2), the diaphragm (the polyethylene film with the thickness of 8 mu m) and the negative plate prepared in the step (3), winding to obtain a winding core, sealing the winding core in an aluminum plastic film, and injecting electrolyte (EC: DEC: EMC=2:3:5, liPF) 6 Concentration is 1 mol/L), and the battery is obtained through ageing, formation and separation.
Example 2
With reference to example 1, the difference is that steps (1) and (2), in particular:
the additive (LiFeO) 2 The surface is coated with soft carbon, wherein the mass ratio of element Fe to element C is about 10: 1) Mixing conductive carbon black and polyvinylidene fluoride according to the mass ratio of 50:15:35, adding N-methyl pyrrolidone, stirring uniformly to obtain coating slurry, wherein the solid content is 70%, and mixingThe coating slurry is coated on the two side surfaces of an aluminum foil (the thickness is 9 mu m), and the current collector is obtained by drying, wherein the thickness of the coating is 3 mu m, the thickness of the positive electrode active material layer is 45 mu m, and the ratio of the mass of element Co in lithium cobaltate to the mass of element Fe in the additive is about 63:1.
Example 3
With reference to example 1, the difference is that steps (1) and (2), in particular:
the additive (LiFeO) 2 The surface is coated with soft carbon, wherein the mass ratio of element Fe to element C is about 20: 1) Mixing conductive carbon black and polyvinylidene fluoride according to the mass ratio of 80:5:15, adding N-methyl pyrrolidone, stirring uniformly to obtain coating slurry, wherein the solid content is 70%, coating the coating slurry on the surfaces of two sides of an aluminum foil (the thickness is 9 mu m), and drying to obtain a current collector, wherein the thickness of the coating is 2 mu m, the thickness of a positive electrode active material layer is 60 mu m, and the mass ratio of element Co in lithium cobaltate to element Fe in an additive is about 77:1.
Example 4 group
This set of examples is carried out with reference to example 1, except that the type of additive is changed, in particular:
example 4a, replacement of additives with "LiFeO" of the same quality 2 Surface-coated soft carbon and Fe 2 O 3 Surface-coated soft carbon mixture, liFeO 2 With Fe 2 O 3 The mass ratio of the element Fe to the element C is 1:1, and the mass ratio of the element Fe to the element C is 15:1", wherein the ratio of the mass of the element Co in the lithium cobaltate to the mass of the element Fe in the additive is about 19:1, a step of;
example 4b substitution of additives with "LiFeO" of the same quality 2 Surface-coated soft carbon and Fe 3 O 4 Surface-coated soft carbon mixture, liFeO 2 With Fe 3 O 4 The mass ratio of the element Fe to the element C is 1:1, and the mass ratio of the element Fe to the element C is 15:1", wherein the ratio of the mass of the element Co in the lithium cobaltate to the mass of the element Fe in the additive is about 19:1, a step of;
example 4c, substitution of additives for "LiFe" of the same mass 0.8 Al 0.2 O 2 Surface coated soft carbon "(wherein the mass ratio of elemental Fe to elemental C is 15:1), wherein the mass ratio of elemental Co in lithium cobaltate to elemental Fe in the additive is about 20:1.
example 5 group
This set of examples is carried out with reference to example 1, except that the mass ratio of the elements Fe and C in the additive is varied, in particular:
in example 5a, the mass ratio of element Fe to element C is 6:1, wherein the ratio of the mass of elemental Co in the lithium cobaltate to the mass of elemental Fe in the additive is about 22:1, a step of;
in example 5b, the mass ratio of element Fe to element C is 25:1, wherein the ratio of the mass of elemental Co in the lithium cobaltate to the mass of elemental Fe in the additive is about 20:1.
example 6 group
This set of examples is performed with reference to example 1, except that the thickness of the coating is varied, in particular:
the coating thickness in example 6a was 0.5 μm, wherein the ratio of the mass of elemental Co in lithium cobaltate to the mass of elemental Fe in the additive was about 165:1, a step of;
the coating thickness in example 6b was 7 μm, wherein the ratio of the mass of elemental Co in lithium cobaltate to the mass of elemental Fe in the additive was about 12:1.
example 7 group
This set of examples is carried out with reference to example 1, except that the mass content of additives in the coating is varied, in particular:
example 7a, an additive, conductive carbon black and polyvinylidene fluoride were mixed in a mass ratio of 30:15:55, wherein the mass ratio of elemental Co in lithium cobaltate to elemental Fe in the additive was about 52:1, a step of;
example 7b, an additive and polyvinylidene fluoride were mixed in a mass ratio of 99:1, wherein the mass ratio of elemental Co in lithium cobaltate to elemental Fe in the additive was about 16:1.
example 8 group
This set of examples is performed with reference to example 4a, except that LiFeO is changed 2 With Fe 2 O 3 Mass ratio of (3), in particular:
example 8a, additive LiFeO 2 Surface-coated soft carbon and Fe 2 O 3 Surface-coated soft carbon mixture, wherein, liFeO 2 With Fe 2 O 3 The mass ratio of the element Fe to the element C is 2:1, and the mass ratio of the element Fe to the element C is 15:1, the ratio of the mass of elemental Co in lithium cobaltate to the mass of elemental Fe in the additive is about 19:1, a step of;
example 8b, additive LiFeO 2 Surface-coated soft carbon and Fe 2 O 3 Surface-coated soft carbon mixture, wherein, liFeO 2 With Fe 2 O 3 The mass ratio of the element Fe to the element C is 1:2, and the mass ratio of the element Fe to the element C is 15:1, the ratio of the mass of elemental Co in lithium cobaltate to the mass of elemental Fe in the additive is about 18:1.
example 9
Reference is made to example 1, except that the material containing element C in the additive is modified, in particular: replacement of additives with "LiFeO" of the same quality 2 Surface coated hard carbon ", wherein the mass ratio of elemental Fe to elemental C is about 15:1.
example 10 group
This set of examples is performed with reference to example 1, except that the base layer is modified, in particular:
example 10a, replacing aluminum foil (9 μm in thickness) with an aluminum layer+polymer layer composite foil (wherein the polymer layer is 6 μm thick, the aluminum layers are disposed on both sides of the polymer layer, the single layer aluminum layer is 1.5 μm thick, and the polymer layer is polyethylene terephthalate);
example 10b aluminum foil (9 μm in thickness) was replaced with an aluminum layer + polymer layer composite foil (wherein the polymer layer was 6 μm thick, the aluminum layers were disposed on either side of the polymer layer, the single layer aluminum layer was 1.5 μm thick, and the polymer layer was polypropylene).
Comparative example 1
With reference to example 1, the difference is that steps (1) and (2), in particular:
mixing lithium cobaltate (Dv 50 is 15 mu m), conductive carbon black and polyvinylidene fluoride according to the mass ratio of 97:1:2, adding N-methyl pyrrolidone, stirring uniformly to obtain positive electrode slurry, wherein the solid content is 70%, uniformly coating the positive electrode slurry on aluminum foil (the thickness is 9 mu m), drying, rolling and cutting to obtain the positive electrode plate.
Comparative example 2
Reference example 1 was followed except that the additive was replaced with FeCO of the same mass 3 Wherein FeCO 3 The XRD diffraction pattern of (2) theta is more than or equal to 42.8 degrees and less than or equal to 44 degrees and 44 degrees<2 theta is less than or equal to 45.2 degrees, and does not have diffraction peaks.
The specific parameters in examples 1-10 and comparative examples 1-2 are shown in Table 1.
TABLE 1
Test example I
XRD testing
XRD testing was performed on the coating layers of the positive electrode sheets prepared in example 1 and examples 4a to 4c, and specific test conditions were as follows:
the X-ray tube used a copper target, a tube voltage of 45kV, a tube current of 40mA, a scan range of 10-90, a scan step length of 0.013, a one-step time of 48.2s, and test results shown in FIG. 5, wherein FIG. 5 (a) is the XRD pattern of the coating in example 1, FIG. 5 (b) is the XRD pattern of the coating in example 4a, FIG. 5 (c) is the XRD pattern of the coating in example 4b, and FIG. 5 (d) is the XRD pattern of the coating in example 4 c.
Test example II
(1) Needling test
The batteries obtained in examples and comparative examples were subjected to a needling test, and the specific test method is as follows:
the cells were charged to 100% SOC at room temperature (25 ℃) and penetrated at a rate of 50mm/s through the geometric center of the cell using a steel needle having a diameter of 4mm, 10 cells were tested per set, and the results are shown in Table 2.
(2) Internal resistance test
The batteries obtained in examples and comparative examples were subjected to internal resistance tests, and the specific test methods were as follows:
the results are shown in Table 2, using an AC internal resistance meter, with an AC signal amplitude of 10mV, a frequency of 1000 Hz.+ -.100 Hz, and a battery of 50% SOC.
(3) Cycle capacity retention test
The batteries obtained in examples and comparative examples were subjected to a cyclic capacity retention test, and the specific test methods were as follows:
the ratio of the 200 th cycle capacity divided by the 1 st cycle capacity was calculated as the capacity retention rate by repeating 200 th cycle under normal temperature (25 ℃) conditions, charging to 4.48V at a constant current and constant voltage, discharging to 3V at a cutoff current of 0.05C and discharging to 0.5C, and the results are shown in Table 2.
(4) Energy density testing
The batteries prepared in examples and comparative examples were subjected to energy density testing as follows:
charging the battery to 100% soc, discharging 0.2c to 3.0V, recording discharge capacity and average voltage; finally, the cells were charged to 50% soc, the thickness was recorded and the battery volume was calculated. Energy density = capacity x average voltage/battery volume, the results are reported in table 2.
TABLE 2
As can be seen from table 2, compared with the comparative example, the battery prepared by the current collector of the present invention significantly improves the passing rate and the retention rate of the circulation capacity of the needling test without significantly affecting the internal resistance.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims (12)

1. A current collector comprising a substrate layer and a coating on at least one side surface of the substrate layer; the XRD diffraction pattern of the coating has diffraction peaks at 42.8 degrees-2 theta-44 degrees and 44 degrees-2 theta-45.2 degrees; the coating contains the following elements: fe. O and C.
2. A current collector according to claim 1, wherein the XRD diffractogram of the coating has diffraction peaks at 43 ° -2 Θ -43.9 ° and 44.2 ° -2 Θ -45.1 °;
preferably, the XRD diffraction pattern of the coating has diffraction peaks at 43.2 DEG.ltoreq.2θ.ltoreq.43.5 DEG and 44.5 DEG.ltoreq.2θ.ltoreq.44.9 ℃.
3. The current collector of claim 1, wherein the base layer comprises a polymer layer and conductive layers on opposite side surfaces of the polymer layer, or the base layer comprises a conductive layer;
and/or the polymer layer comprises at least one of polyoxymethylene, polyethylene, polyvinylmethyl ether, polyvinylethyl ether, a copolymer of ethylene and propylene, polyvinyl alcohol, polyvinyl acetate, polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polyvinyl chloride, polyvinylidene chloride, polypropylene, polyacrylic acid, polymethyl methacrylate, polyethyl acrylate, poly (alpha-nitrilylacrylate), polyacrylonitrile, polyisobutylene rubber, neoprene rubber, natural rubber, ancient rubber, styrene butadiene rubber, polydecylene formamide, polyhexamethylene adipamide, polyhexamethylene sebacamide, polyethylene terephthalate, polyethylene oxide, polyphenylene sulfide, poly [ bis (trifluoroethoxy) phosphazene ], polydimethylsiloxane, polyvinylcarbazole, polytetrafluoroethylene, polyacrylamide, polyethylene terephthalate, polybutylene terephthalate, and polycarbonate;
and/or the conductive layer comprises metallic aluminum or an aluminum alloy.
4. The current collector according to claim 1, wherein the additive comprises a substance represented by formula I, the surface of the substance being coated with a material containing element C,
Li x Fe y-a M a O z I，
wherein M comprises at least one of Al, mg, ti and Zr, x is more than or equal to 0 and less than or equal to 1, y is 1, 2 or 3, a is more than or equal to 0 and less than or equal to 0.3,1 and z is more than or equal to 4, and the requirements are as follows: x/z is less than or equal to 0.5, and y/z is less than or equal to 1;
preferably, x/z is 0 or 0.5;
preferably, 0.5.ltoreq.y/z.ltoreq.1.
5. The current collector of claim 4, wherein the formula I comprises LiFeO 2 、Fe 3 O 4 、Fe 2 O 3 And LiFe 0.8 Al 0.2 O 2 At least one of (a) and (b);
and/or the material containing element C comprises a carbon material;
preferably, the carbon material includes at least one of hard carbon, soft carbon, carbon black, conductive graphite, carbon nanotubes, and graphene.
6. The current collector according to claim 4, wherein, in the additive, a ratio of a mass of element Fe to a mass of element C is (5-30): 1, a step of; preferably (10-20): 1.
7. the current collector according to claim 1, wherein an intensity of a diffraction peak at 44 ° <2Θ+.45.2° is equal to or greater than an intensity of a diffraction peak at 42.8 ° +.2Θ+.44°; preferably, the intensity of the diffraction peak at 44 ° <2θ+.45.2° is greater than the intensity of the diffraction peak at 42.8+.2θ+.44°;
and/or the thickness of the coating is 0.1 μm to 20 μm.
8. A current collector according to claim 1, wherein the additive is present in an amount of 20-99 wt%, based on the total weight of the coating; preferably 50-80% by weight.
9. A positive electrode sheet, characterized in that the positive electrode sheet comprises the current collector according to any one of claims 1 to 8.
10. The positive electrode sheet according to claim 9, wherein the positive electrode sheet further comprises a positive electrode active material layer on at least one side surface of the current collector; the positive electrode active material layer includes a positive electrode active material including at least one of: lithium cobaltate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium nickel cobalt manganese aluminate, lithium manganate, lithium nickel manganate, lithium nickelate, lithium iron phosphate, lithium iron manganese phosphate, lithium vanadium phosphate and lithium-rich manganese;
preferably, the positive electrode active material includes lithium cobaltate;
more preferably, the ratio of the mass of the element Co in the positive electrode active material to the mass of the element Fe in the additive is not less than 10:1.
11. the positive electrode sheet according to claim 10, wherein a ratio of a thickness of the positive electrode active material layer to a thickness of the coating layer is (3-160): 1, a step of; preferably (7-30): 1, a step of;
and/or the positive electrode active material layer has a thickness of 15 μm to 80 μm; preferably 30 μm to 60. Mu.m.
12. A battery comprising the current collector of any one of claims 1 to 8 and/or the positive electrode sheet of any one of claims 9 to 11.
CN202311513448.9A 2023-11-14 2023-11-14 Current collector, positive plate and battery Pending CN117525433A (en)

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