CN117133862A - Positive electrode plate, preparation method thereof, battery and electric equipment - Google Patents

Positive electrode plate, preparation method thereof, battery and electric equipment Download PDF

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Publication number
CN117133862A
CN117133862A CN202311409281.1A CN202311409281A CN117133862A CN 117133862 A CN117133862 A CN 117133862A CN 202311409281 A CN202311409281 A CN 202311409281A CN 117133862 A CN117133862 A CN 117133862A
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China
Prior art keywords
positive electrode
capacity
catalyst
compensator
battery
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CN202311409281.1A
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Chinese (zh)
Inventor
吴凯
景二东
张楠楠
谢浩添
王东浩
陈晓
孙信
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Priority to CN202311409281.1A priority Critical patent/CN117133862A/en
Publication of CN117133862A publication Critical patent/CN117133862A/en
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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
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/204—Racks, modules or packs for multiple batteries or multiple cells
    • H01M50/207—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape
    • H01M50/209—Racks, modules or packs for multiple batteries or multiple cells characterised by their shape adapted for prismatic or rectangular cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/20—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders
    • H01M50/249—Mountings; Secondary casings or frames; Racks, modules or packs; Suspension devices; Shock absorbers; Transport or carrying devices; Holders specially adapted for aircraft or vehicles, e.g. cars or trains
    • 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

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The application discloses a positive pole piece, a preparation method thereof, a battery and electric equipment, wherein the positive pole piece comprises a positive active material layer; and a capacity compensation layer provided on one side of the positive electrode active material layer, the capacity compensation layer including a catalyst and a capacity compensator having an average particle diameter of less than or equal to 2 μm. Thereby, the probability of contact between the catalyst and the capacity compensator is improved, the decomposition potential of the capacity compensator is reduced, and the capacity retention rate and the service life of the battery are improved.

Description

Positive electrode plate, preparation method thereof, battery and electric equipment
Technical Field
The application relates to the field of batteries, in particular to a positive pole piece, a preparation method thereof, a battery and electric equipment.
Background
The battery is not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles, and the like, as well as a plurality of fields such as military equipment, aerospace, and the like. A solid electrolyte film (SEI film) is formed in the formation of the battery, and active metal ions are consumed in the formation of the SEI film, so that irreversible capacity loss caused by the formation of the SEI film is compensated, and a capacity compensator is included in the battery. However, in general, the decomposition potential of the capacity compensator is high, and in order to improve the decomposition efficiency of the capacity compensator, the electrolyte is deteriorated by an increase in voltage, thereby reducing the capacity retention rate of the battery.
Disclosure of Invention
In view of the technical problems in the background art, the application provides a positive electrode plate, which aims to improve the capacity retention rate of a battery containing the positive electrode plate.
A first aspect of the present application provides a positive electrode sheet including a positive electrode active material layer including a positive electrode active material; and a capacity compensation layer provided on one side of the positive electrode active material layer, the capacity compensation layer including a catalyst and a capacity compensator having an average particle diameter of less than or equal to 2 μm.
The positive electrode plate comprises a positive electrode active material layer and a capacity compensation layer, wherein the capacity compensation layer comprises a catalyst and a capacity compensation agent, the catalyst can reduce the decomposition activation energy of the capacity compensation agent by adding the catalyst into the capacity compensation layer, so that active metal ions of the capacity compensation agent are more easily separated out, the decomposition potential of the capacity compensation agent is reduced, and the average particle size of the capacity compensation agent is controlled to be less than or equal to 2 mu m.
According to some embodiments of the application, the volume compensator has an average particle size of 50nm-2 μm.
According to some embodiments of the application, the volume compensator has an average particle size of 50nm to 500nm.
Thus, by setting the average particle diameter of the capacity compensator in the above range, the probability of contact between the catalyst and the capacity compensator can be further increased, the reactive sites of the capacity compensator can be increased, the ion and electron transport capacity of the capacity compensator can be improved, the decomposition potential of the capacity compensator can be further reduced, the decomposition efficiency and utilization rate of the capacity compensator can be improved, the capacity retention rate of the battery can be further improved, and the life of the battery can be prolonged.
According to some embodiments of the application, the average particle size of the catalyst is less than or equal to the average particle size of the capacity compensator. Therefore, the probability of contact between the catalyst and the capacity compensator is improved, the reaction site of the capacity compensator is increased, the transmission capacity of the capacity compensator to ions and electrons is improved, the decomposition potential of the capacity compensator is further reduced, the decomposition efficiency and the utilization rate of the capacity compensator are improved, the capacity retention rate of a battery is further improved, and the service life of the battery is prolonged.
According to some embodiments of the application, the catalyst has an average particle size of 50nm to 2 μm.
According to some embodiments of the application, the catalyst has an average particle size of 50nm to 500nm.
Thus, by setting the average particle diameter of the catalyst in the above range, the probability of contact between the catalyst and the capacity compensator can be further improved, the active ions of the capacity compensator can be more easily extracted, and the decomposition potential of the capacity compensator can be reduced.
According to some embodiments of the present application,the BET specific surface area of the catalyst was 87m 2 /g-200m 2 And/g. Thus, by setting the BET specific surface area of the catalyst in the above range, the probability of contact between the catalyst and the capacity compensator can be increased, the active ions of the capacity compensator can be more easily extracted, and the decomposition potential of the capacity compensator can be reduced.
According to some embodiments of the application, the catalyst has a BET specific surface area of 130m 2 /g-200m 2 /g。
According to some embodiments of the application, the ratio of the mass of the catalyst to the mass of the capacity compensator is (5-40) based on the total mass of the capacity compensator: 100. thus, the decomposition potential of the capacity compensator is reduced, and the capacity compensation efficiency is improved.
According to some embodiments of the application, the ratio of the mass of the capacity compensator to the mass of the positive electrode active material is (0.5-20) based on the total mass of the positive electrode sheet: 100. thereby, the efficiency of capacity compensation is improved.
According to some embodiments of the application, the catalyst comprises a metal compound. Thus, the active metal ions of the capacity compensator are more easily extracted, thereby lowering the decomposition potential of the capacity compensator.
According to some embodiments of the application, at least part of the surface of the metal compound has a carbon coating. Thus, the carbon coating layer can improve the electron conductivity of the catalyst, further reduce the decomposition potential of the capacity compensator, and improve the capacity compensation efficiency.
According to some embodiments of the application, the carbon coating layer comprises a mass fraction of 5% -30% based on the total mass of the metal compound and the carbon coating layer. This improves the electron conductivity of the catalyst and further promotes the removal of the active metal ions from the capacity compensator.
According to some embodiments of the application, the metal compound comprises at least one of a transition metal oxide, a transition metal carbide, a transition metal nitride, a transition metal sulfide, or a transition metal phosphide.
According to some embodiments of the application, theThe capacity compensator comprises a lithium supplementing agent and/or a sodium supplementing agent, wherein the lithium supplementing agent comprises Li 2 O、Li 2 O 2 、Li 2 CO 3 、Li 2 C 2 O 4 、Li 2 C 4 O 4 、Li 2 S、Li 2 Se、Li 2 Se 2 Or LiF; the sodium supplementing agent comprises Na 2 O、Na 2 O 2 、Na 2 CO 3 、Na 2 C 2 O 4 、Na 2 C 4 O 4 、Na 2 S、Na 2 Se、Na 2 Se 2 Or NaF.
According to some embodiments of the application, the positive electrode sheet further comprises: and the capacity compensation layer is positioned on one side of the positive electrode active material layer away from the positive electrode current collector. Therefore, the capacity compensation efficiency is improved, and meanwhile, the structural stability of the positive pole piece is improved.
The second aspect of the application provides a preparation method of a positive electrode plate, comprising the following steps: forming a positive electrode active material layer including a positive electrode active material; and forming a capacity compensation layer on one side of the positive electrode active material layer, the capacity compensation layer including a catalyst and a capacity compensator having an average particle diameter of less than or equal to 2 μm.
Therefore, the positive electrode plate prepared by the method provided by the application comprises the catalyst and the capacity compensator, the catalyst can reduce the decomposition activation energy of the capacity compensator, so that active ions of the capacity compensator are easier to be separated out, and the decomposition potential of the capacity compensator is reduced. Further, by setting the average particle diameter of the capacity compensator in the above range, the probability of contact between the catalyst and the capacity compensator can be increased, the reactive sites of the capacity compensator can be increased, the ion and electron transport capacity can be improved, the decomposition potential of the capacity compensator can be further reduced, the decomposition efficiency and the utilization rate of the capacity compensator can be improved, the capacity retention rate of the battery can be further improved, and the life of the battery can be prolonged.
According to some embodiments of the application, the method of forming the capacity compensation layer further comprises: a catalyst layer is formed on one side of the positive electrode active material layer, and the capacity compensator is formed in the catalyst layer by an electrochemical deposition method. Therefore, the electrochemical deposition can form the capacity compensator with smaller average grain diameter on the catalyst in situ, so that the probability of the contact between the catalyst and the capacity compensator is improved, the reaction site of the capacity compensator is increased, the transmission capacity of ions and electrons is improved, the decomposition potential of the capacity compensator is further reduced, the decomposition efficiency and the utilization rate of the capacity compensator are improved, the capacity retention rate of a battery is further improved, and the service life of the battery is prolonged.
According to some embodiments of the application, the catalyst layer has a porosity of 30% to 70%. Thereby improving the efficiency of in situ deposition of the capacity compensator on the catalyst surface during electrochemical deposition.
According to some embodiments of the application, the catalyst layer has a porosity of 30% -50%. Thereby improving the efficiency of in situ deposition of the capacity compensator on the catalyst surface during electrochemical deposition.
The third aspect of the application provides a battery comprising the positive electrode sheet provided by the first aspect of the application or the positive electrode sheet prepared by the method provided by the second aspect of the application. Thereby, the capacity retention rate of the battery is improved.
A fourth aspect of the application provides a powered device comprising a battery provided in the third aspect of the application. Thereby, the lifetime of the consumer is increased.
Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to designate like parts throughout the accompanying drawings. In the drawings:
fig. 1 is a schematic structural view of a positive electrode sheet according to an embodiment of the present application.
Fig. 2 is an SEM image of a catalyst and a capacity compensator according to an embodiment of the present application.
Fig. 3 is a schematic structural view of a positive electrode sheet according to another embodiment of the present application.
Fig. 4 is a schematic view of a battery according to an embodiment of the present application.
Fig. 5 is an exploded view of the battery of the embodiment of the present application shown in fig. 4.
Fig. 6 is a schematic view of a battery module according to an embodiment of the present application.
Fig. 7 is a schematic view of a battery pack according to an embodiment of the present application.
Fig. 8 is an exploded view of the battery pack of the embodiment of the present application shown in fig. 7.
Fig. 9 is a schematic diagram of a powered device using a battery as a power source according to an embodiment of the present application.
Reference numerals illustrate:
1, a battery pack; 2, upper box body; 3, lower box body; 4, a battery module; 5 a secondary battery; 51 a housing; 52 electrode assembly; 53 cover plates; 521 positive pole piece; 5211 positive electrode active material layer; 5212 capacity compensating layer; 5213 positive electrode current collector.
Detailed Description
Embodiments of the technical scheme of the present application are described in detail below. The following examples are only for more clearly illustrating the technical aspects of the present application, and thus are merely examples, and are not intended to limit the scope of the present application.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described herein may be combined with other embodiments.
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 of the embodiments of the present application, the term "and/or" is merely an association relationship describing an association object, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having" and any variations thereof in the description of the application and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion.
Currently, the more widely the battery is used in view of the development of market situation. The battery is not only applied to energy storage power supply systems such as hydraulic power, firepower, wind power and solar power stations, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric automobiles, and the like, as well as a plurality of fields such as military equipment, aerospace, and the like. With the continuous expansion of the battery application field, the market demand thereof is also continuously expanding.
In the formation process of the battery, an SEI film can be formed on the surface of the negative electrode, a large amount of active metal ions can be consumed in the formation process of the SEI film, and the initial effect of the battery is reduced. In order to improve the initial efficiency of the battery, capacity compensation may be performed in advance for the negative electrode or the positive electrode. When the positive electrode is subjected to capacity compensation, an additive rich in active metal ions is generally adopted, a capacity compensation layer is established on the positive electrode plate, enough active metal ions are released in the first-week charge and discharge process, and irreversible capacity loss caused by SEI film generation is compensated. However, the decomposition potential of the capacity compensator is high, and the electrolyte is deteriorated by an increase in voltage, so that the capacity compensation effect of the capacity compensator is limited.
The application provides a positive electrode plate, which comprises a positive electrode active material layer and a capacity compensation layer, wherein the capacity compensation layer comprises a catalyst and a capacity compensation agent, the decomposition potential of the capacity compensation agent can be reduced by adding the catalyst into the capacity compensation layer, the probability of the capacity compensation agent contacting with the catalyst can be improved by reducing the average particle size of the capacity compensation agent, the reaction site of the capacity compensation agent is increased, the transmission capacity of ions and electrons is improved, the decomposition potential of the capacity compensation agent is further reduced, the decomposition efficiency and the utilization rate of the capacity compensation agent are improved, the capacity retention rate of a battery is further improved, and the service life of the battery is prolonged.
The positive pole piece disclosed by the embodiment of the application is suitable for lithium ion batteries and sodium ion batteries, and the battery disclosed by the embodiment of the application can be used for electric equipment using the battery as a power supply or various energy storage systems using the battery as an energy storage element. The powered device may include, but is not limited to, a cell phone, tablet, notebook computer, electric toy, electric tool, battery car, electric car, ship, spacecraft, and the like. Among them, the electric toy may include fixed or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric plane toys, and the like, and the spacecraft may include planes, rockets, space planes, and spacecraft, and the like.
The first aspect of the present application provides a positive electrode tab 521, referring to fig. 1, the positive electrode tab 521 includes a positive electrode active material layer 5211, and the positive electrode active material layer 5211 includes a positive electrode active material; a capacity compensation layer 5212, the capacity compensation layer 5212 being provided on one side of the positive electrode active material layer 5211, the capacity compensation layer 5212 comprising a catalyst and a capacity compensator having an average particle diameter of 2 μm or less.
The positive electrode plate 521 comprises a positive electrode active material layer 5211 and a capacity compensation layer 5212, wherein the capacity compensation layer 5212 comprises a catalyst and a capacity compensation agent, the catalyst is added into the capacity compensation layer 5212, so that the decomposition activation energy of the capacity compensation agent can be reduced, active metal ions of the capacity compensation agent can be more easily separated, the decomposition potential of the capacity compensation agent can be reduced, the average particle size of the capacity compensation agent is controlled to be less than or equal to 2 mu m, the probability of the catalyst contacting the capacity compensation agent can be improved, the reaction site of the capacity compensation agent can be increased, the transmission capacity of ions and electrons can be improved, the decomposition potential of the capacity compensation agent can be further reduced, the decomposition efficiency and the utilization rate of the capacity compensation agent can be improved, the capacity retention rate of a battery can be improved, and the service life of the battery can be prolonged. When the particle diameter of the capacity compensator is > 2 μm, the contact efficiency of the capacity compensator and the catalyst is lowered due to the excessively large average particle diameter of the capacity compensator, which may reduce the catalytic effect of the catalyst.
According to some embodiments of the application, the volume compensator may have an average particle size of 20nm, 40nm, 50nm, 100nm, 500nm, 1 μm, 1.5 μm or 2 μm, etc., or may be in the range of any of the numerical compositions described above. According to some embodiments of the application, the volume compensator may have an average particle size of 50nm to 2 μm. According to other specific embodiments of the present application, the volume compensator may have an average particle size of 50nm to 500nm.
According to some embodiments of the application, the average particle size of the catalyst is less than or equal to the average particle size of the capacity compensator. Therefore, the probability of contact between the catalyst and the capacity compensator is improved, the reaction site of the capacity compensator is increased, the transmission capacity of the capacity compensator to ions and electrons is improved, the decomposition potential of the capacity compensator is further reduced, the decomposition efficiency and the utilization rate of the capacity compensator are improved, the capacity retention rate of a battery is further improved, and the service life of the battery is prolonged.
According to some embodiments of the application, the catalyst has an average particle size of 50nm-2 μm, e.g., may be 50nm, 100nm, 500nm, 1 μm, 1.5 μm or 2 μm, etc., or may be in the range of any of the numerical compositions described above. According to other embodiments of the application, the catalyst may have an average particle size of 50nm to 500nm.
According to the application, the capacity compensator and the catalyst can be distinguished by combining a FEI Talos FS200X transmission electron microscope with an X-ray energy spectrometer (EDS), specifically, 0.01g of capacity compensation layer powder is placed in the transmission electron microscope, and the magnification is adjusted to observe the sample, so that the sample is clear and the quantity can be distinguished. The capacity compensator and the catalyst can be distinguished from a specific metal element in the catalyst by EDS elemental analysis. And respectively counting the particle sizes (not less than 10 particles) of the capacity compensator and the catalyst particles, and obtaining the average particle sizes of the capacity compensator and the catalyst particles by taking the average value.
According to some embodiments of the application, referring to fig. 2, the capacity compensator coats at least a portion of the surface of the catalyst. Therefore, the probability of contact between the catalyst and the capacity compensator is improved, the reaction site of the capacity compensator is increased, the decomposition potential of the capacity compensator is further reduced, the decomposition efficiency and the utilization rate of the capacity compensator are improved, the capacity retention rate of a battery is further improved, and the service life of the battery is prolonged.
According to some embodiments of the application, the capacity compensator may include a lithium and/or sodium supplement including Li 2 O、Li 2 O 2 、Li 2 CO 3 、Li 2 C 2 O 4 、Li 2 C 4 O 4 、Li 2 S、Li 2 Se、Li 2 Se 2 Or LiF; the sodium supplementing agent comprises Na 2 O、Na 2 O 2 、Na 2 CO 3 、Na 2 C 2 O 4 、Na 2 C 4 O 4 、Na 2 S、Na 2 Se、Na 2 Se 2 Or NaF. Thus, when the battery is a lithium ion battery, the capacity compensator employs a lithium supplementing agent, such as Li 2 O、Li 2 O 2 、Li 2 CO 3 、Li 2 C 2 O 4 、Li 2 C 4 O 4 、Li 2 S、Li 2 Se、Li 2 Se 2 Or LiF, the probability of contact between the lithium supplementing agent and the catalyst can be improved, so that the reaction site of the lithium supplementing agent is increased, the decomposition potential of the lithium supplementing agent is further reduced, the decomposition efficiency and the utilization rate of the lithium supplementing agent are improved, the capacity retention rate of the battery is improved, and the service life of the battery is prolonged; when the battery is a sodium ion battery, the capacity compensator employs a sodium supplementing agent, e.g., na 2 O、Na 2 O 2 、Na 2 CO 3 、Na 2 C 2 O 4 、Na 2 C 4 O 4 、Na 2 S、Na 2 Se、Na 2 Se 2 Or at least one of NaF, can raise the probability of contacting sodium supplement agent with catalyst, and then increase the reaction site of sodium supplement agent, further reduce the decomposition potential of sodium supplement agent, raise decomposition efficiency and utilization rate of sodium supplement agent, and then raise the capacity retention rate of battery, raise the life-span of battery.
According to some embodiments of the application, the BET specific surface area of the catalyst may be 87m 2 /g-200m 2 /g, for example, may be 87m 2 /g、100m 2 /g、120m 2 /g、140m 2 /g、160m 2 /g、180m 2 /g or 200m 2 /g, etc., or may be in the range of any of the numerical compositions described above. Therefore, the probability of contact between the catalyst and the capacity compensator is improved, the reaction site of the capacity compensator is increased, the decomposition potential of the capacity compensator is further reduced, the decomposition efficiency and the utilization rate of the capacity compensator are improved, the capacity retention rate of a battery is further improved, and the service life of the battery is prolonged. According to some embodiments of the application, the BET specific surface area of the catalyst may be 130m 2 /g-200m 2 /g。
In the application, the thermal decomposition temperature of the catalyst is about 1000-2000 ℃, the thermal decomposition temperature of the capacity compensator is about 300-600 ℃, the capacity compensation layer on the positive pole piece is scraped off, the catalyst is heated to 700-900 ℃ in nitrogen atmosphere, and the capacity compensator is decomposed and then separated to obtain the catalyst. The BET specific surface area can be measured by referring to the following method: about 7g of the sample was put into a 9cc bulb-equipped long tube using a U.S. microphone multi-station type full-automatic specific surface area and pore analyzer GeminiVII2390, deaerated at 200 ℃ for 2 hours, and then put into a host computer for testing to obtain BET (specific surface area) data of the catalyst.
According to some embodiments of the application, the catalyst may comprise a metal compound. Thus, the active metal ions of the capacity compensator are more easily extracted, thereby lowering the decomposition potential of the capacity compensator.
According to some embodiments of the application, at least part of the surface of the metal compound has a carbon coating. Thus, the electron conductivity of the catalyst can be improved, the decomposition potential of the capacity compensator can be further reduced, and the capacity compensation efficiency can be improved.
According to some embodiments of the application, the carbon coating layer has a mass ratio of 5% -30%, for example, may be 5%, 10%, 15%, 20%, 25% or 30%, etc., or may be in the range of any of the numerical compositions mentioned above, based on the total mass of the metal compound and the carbon coating layer. This improves the electron conductivity of the catalyst and further promotes the removal of the active metal ions from the capacity compensator.
In the present application, the contents of the metal compound and the carbon coating layer can be measured using a TGA-601 thermogravimetric analyzer. Introducing oxygen atmosphere into a metal compound with a carbon coating layer on the surface in a thermogravimetric analyzer to heat, reacting carbon materials in the mixed material with oxygen to generate carbon dioxide, and obtaining the content M of the carbon coating layer through weight loss mass 1 The metal compound content is (100% -M) 1 ）。
According to some embodiments of the application, the metal compound comprises at least one of a transition metal oxide, a transition metal carbide, a transition metal nitride, a transition metal sulfide, or a transition metal phosphide. Therefore, the transition metal has a valence layer d orbit which is not filled with electrons, the electron cloud is easy to deform, and electron exchange is easy to be realized with the capacity compensator, so that the capacity compensator is catalyzed to decompose, and the capacity compensator can exert more capacity under low potential.
According to some embodiments of the application, the capacity compensation layer includes a conductive agent including at least one of superconducting carbon, ketjen black, acetylene black, carbon nanotubes, or graphene.
According to some embodiments of the application, the ratio of the mass of the catalyst to the mass of the capacity compensator may be (5-40), based on the total mass of the capacity compensation layer 5212: 100, for example, may be 5:100, 10:100, 15:100, 20:100, 25:100, 30:100, 35:100, 40:100, etc., or may be in the range of any of the numerical compositions described above. Thus, by setting the ratio of the content of the catalyst to the content of the capacity compensator in the above range, the probability of contact between the catalyst and the capacity compensator is improved, the decomposition potential of the capacity compensator is reduced, the decomposition efficiency and the utilization rate of the capacity compensator are improved, the capacity retention rate of the battery is further improved, and the life of the battery is prolonged.
According to some embodiments of the application, the mass of the catalyst may be (0.002-0.024) g/1540.25mm based on the total mass of the capacity compensation layer 5212 2 For example, it may be 0.002g/1540.25mm 2 、0.004g/1540.25mm 2 、0.006g/1540.25mm 2 、0.008g/1540.25mm 2 、0.01g/1540.25mm 2 、0.012g/1540.25mm 2 、0.014g/1540.25mm 2 、0.016g/1540.25mm 2 、0.018g/1540.25mm 2 、0.02g/1540.25mm 2 、0.022g/1540.25mm 2 Or 0.024g/1540.25mm 2 Etc., or may be in the range of any of the numerical compositions described above. According to some specific embodiments of the present application, the mass of the catalyst may be (0.002-0.012) g/1540.25mm based on the total mass of the capacity compensation layer 5212 2 . Therefore, the probability of contact between the catalyst and the capacity compensator is improved, the decomposition potential of the capacity compensator is reduced, the decomposition efficiency and the utilization rate of the capacity compensator are improved, the capacity retention rate of the battery is further improved, and the service life of the battery is prolonged.
Here, the reference is made to 0.002g/1540.25mm 2 It means that the mass of the catalyst contained in the capacity compensation layer 5212 per 1540.25 square mm is 0.002g.
According to some embodiments of the application, the capacitance is based on the total mass of the capacitance compensation layer 5212The mass of the compensating agent can be (0.002-0.06) g/1540.25mm 2 For example, it may be 0.002g/1540.25mm 2 、0.01g/1540.25mm 2 、0.015g/1540.25mm 2 、0.02g/1540.25mm 2 、0.025g/1540.25mm 2 、0.03g/1540.25mm 2 、0.035g/1540.25mm 2 、0.04g/1540.25mm 2 、0.045g/1540.25mm 2 、0.05g/1540.25mm 2 、0.055g/1540.25mm 2 Or 0.06g/1540.25mm 2 Etc., or may be in the range of any of the numerical compositions described above. According to some embodiments of the application, the mass of the volume compensation agent may be (0.004-0.045) g/1540.25mm based on the total mass of the volume compensation layer 5212 2 . Therefore, the capacity compensation efficiency is improved, the first efficiency of the battery is improved, and the capacity retention rate of the battery is improved.
Here, the reference is made to 0.002g/1540.25mm 2 It means that the mass of the capacity compensation agent contained in the capacity compensation layer 5212 per 1540.25 square mm is 0.002g.
In the present application, the catalyst content can be measured using a TGA-601 thermogravimetric analyzer. The thermal decomposition temperature of the catalyst is about 1000-2000 ℃, the thermal decomposition temperature of the capacity compensator is about 300-600 ℃, the capacity compensation layer on the positive pole piece is scraped off, nitrogen is introduced into a TGA-601 thermogravimetric analyzer to heat to 700-900 ℃, and the capacity compensator is decomposed and then separated to obtain the catalyst. Obtaining the content M of the capacity compensator by weight loss mass 2 The catalyst content is (100% -M) 2 ）。
According to some embodiments of the present application, the ratio of the mass of the capacity compensator to the mass of the positive electrode active material may be (0.5-20) based on the total mass of the positive electrode tab 521: 100, for example, may be 0.5:100, 1:100, 3:100, 5:100, 7:100, 9:100, 11:100, 13:100, 15:100, 17:100, 19:100, or 20:100, etc., or may be a range of any of the numerical compositions described above. Thus, by making the mass ratio of the capacity compensator to the positive electrode active material within the above range, the capacity extender can not only compensate for the active metal ions consumed in forming the SEI film, but also supplement the active metal ions during the battery cycle, thereby improving the cycle capacity retention rate of the battery.
According to some embodiments of the present application, the mass of the positive electrode active material in the positive electrode active material layer 5211 may be (0.2-0.4) g/1540.25mm based on the total mass of the positive electrode active material layer 5211 2 For example, it may be 0.2g/1540.25mm 2 、0.25g/1540.25mm 2 、0.3g/1540.25mm 2 、0.35g/1540.25mm 2 Or 0.4g/1540.25mm 2 . According to some embodiments of the present application, the mass of the positive electrode active material in the positive electrode active material layer 5211 may be (0.25-0.35) g/1540.25mm based on the total mass of the positive electrode active material layer 5211 2 。
Here, 0.2g/1540.25mm 2 It means that the mass of the positive electrode active material contained in each 1540.25mm positive electrode active material layer 5211 is 0.2g.
In the present application, the quality of the positive electrode active material can be measured using a TGA-601 thermogravimetric analyzer. Scraping the capacity compensation layer and the active material layer on the positive electrode plate in sequence, placing the active material layer material into a thermogravimetric analyzer, introducing oxygen and heating to 400 ℃, and decomposing substances except the positive electrode active material in the active material layer material firstly to obtain the content M of the active material layer material and the active material layer material through weight loss mass 3 The content of the positive electrode active material is (100% -M) 3 ）。
According to some embodiments of the present application, the ratio of the thickness of the capacity compensation layer 5212 to the positive electrode active material layer 5211 may be (15-50): 100, for example, may be 15:100, 20:100, 25:100, 30:100, 35:100, 40:100, 45:100, or 50:100, etc., or may be in the range of any of the numerical compositions described above. Therefore, the capacity compensation efficiency is improved, the thickness of the whole pole piece is reduced, and the energy density of the battery is improved. According to some embodiments of the present application, the ratio of the thickness of the capacity compensation layer 5212 to the positive electrode active material layer 5211 may be (20 to 38): 100.
The thickness test method in the application comprises the following steps: the thickness of the positive electrode tab 521 containing the positive electrode active material layer 5211 and the positive electrode current collector 5213 is a, and the thickness of the positive electrode active material layer 5211 is a-the thickness of the positive electrode current collector measured by a Mitutoyo 0-25mm per million; the thickness of the positive electrode tab 521 containing the positive electrode active material layer 5211, the capacity compensation layer 5212 and the positive electrode current collector 5213 was measured by a Mitutoyo 0-25mm per million and the thickness of the capacity compensation layer 5212 was b-a. Specifically, 10 points can be randomly selected on the positive electrode plate 521 for testing and recording thickness in the thickness testing process, and the average value of the 10 points is taken as thickness data.
According to some embodiments of the application, the thickness of the capacity compensation layer 5212 can be 25 μm-50 μm, for example, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc., or can be in the range of any of the numerical compositions described above. According to some embodiments of the application, the thickness of the capacitance compensation layer 5212 can be 30 μm to 45 μm. Thereby, the efficiency of capacity compensation is improved, and the initial efficiency and capacity retention rate of the battery are improved.
According to some embodiments of the present application, the thickness of the positive electrode active material layer 5211 may be 100 μm to 170 μm, for example, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, or the like, or may be in a range of any of the numerical compositions described above. According to some embodiments of the application, the thickness of the positive electrode active material layer 5211 may be 120 μm to 150 μm.
According to some embodiments of the application, referring to fig. 3, the positive electrode tab 521 may further include: the positive electrode collector 5213, the positive electrode active material layer 5211 is located at a side of the positive electrode collector 5213, and the capacity compensating layer 5212 is located at a side of the positive electrode active material layer 5211 remote from the positive electrode collector 5213. Therefore, the probability of collapsing the positive electrode active material layer 5211 caused by the active ion extraction process in the capacity compensator is reduced, the structural stability of the positive electrode pole piece 521 is improved, and the service life of the battery is prolonged.
According to some embodiments of the application, the positive electrode current collector 5213 may be a metal foil or a composite positive electrode current collector. For example, as the metal foil, aluminum foil may be used. The composite positive electrode current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite positive electrode current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
According to some embodiments of the present application, when the battery is a lithium ion battery, the positive electrode active material may employ a positive electrode active material for lithium ion batteries, which is well known in the art. As an example, the positive electrode active material may include at least one of the following materials: olivine structured lithium-containing phosphates, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material may be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (e.g., liCoO) 2 ) Lithium nickel oxide (e.g. LiNiO) 2 ) Lithium manganese oxide (e.g. LiMnO 2 、LiMn 2 O 4 ) Lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., liNi) 1/3 Co 1/ 3 Mn 1/3 O 2 (also referred to as NCM) 333 ）、LiNi 0.5 Co 0.2 Mn 0.3 O 2 (also referred to as NCM) 523 ）、LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also referred to as NCM) 211 ）、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also referred to as NCM) 622 ）、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM) 811 ) Lithium nickel cobalt aluminum oxide (e.g. LiNi 0.8 Co 0.15 Al 0.05 O 2 ) And at least one of its modified compounds and the like. Examples of olivine structured lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (e.g. LiFePO 4 (also abbreviated as LFP)), composite material of lithium iron phosphate and carbon, and manganese lithium phosphate (such as LiMnPO) 4 ) At least one of a composite material of lithium manganese phosphate and carbon, and a composite material of lithium manganese phosphate and carbon.
According to some embodiments of the application, when the battery is a sodium-ion battery, for example, when the battery is a sodium-ion battery, the positive electrode active material may include, as an example, at least one of a layered transition metal oxide, a polyanion compound, and a prussian blue analog.
Examples of the layered transition metal oxide include:
Na 1-x Cu h Fe k Mn l M 1 m O 2-y wherein M is 1 Is one or more of Li, be, B, mg, al, K, ca, ti, co, ni, zn, ga, sr, Y, nb, mo, in, sn and Ba, 0<x≤0.33，0<h≤0.24，0≤k≤0.32，0<l≤0.68，0≤m<0.1，h+k+l+m＝1，0≤y<0.2；
Na 0.67 Mn 0.7 Ni z M 2 0.3-z O 2 Wherein M is 2 Is one or more of Li, mg, al, ca, ti, fe, cu, zn and Ba, 0<z≤0.1；
Na a Li b Ni c Mn d Fe e O 2 Of which 0.67<a≤1，0<b<0.2，0<c<0.3，0.67<d+e<0.8，b+c+d+e＝1。
Examples of the polyanion compound include:
A 1 f M 3 g (PO 4 ) i O j X 1 3-j wherein A is 1 H, li, na, K and NH 4 One or more of M 3 Is one or more of Ti, cr, mn, fe, co, ni, V, cu and Zn, X 1 Is one or more of F, cl and Br, 0<f≤4，0<g≤2，1≤i≤3，0≤j≤2；
Na n M 4 PO 4 X 2 Wherein M is 4 Is one or more of Mn, fe, co, ni, cu and Zn, X 2 Is one or more of F, cl and Br, 0<n≤2；
Na p M 5 q (SO 4 ) 3 Wherein M is 5 Is one or more of Mn, fe, co, ni, cu and Zn, 0<p≤2，0<q≤2；
Na s Mn t Fe 3-t (PO 4 ) 2 (P 2 O 7 ) Wherein 0 is<s.ltoreq.4, 0.ltoreq.t.ltoreq.3, for example t is 0, 1, 1.5, 2 or 3.
As examples of the above prussian blue analogues, for example, there may be mentioned:
A u M 6 v [M 7 (CN) 6 ] w ·xH 2 o, wherein A is H + 、NH 4 + One or more of alkali metal cations and alkaline earth metal cations, M 6 And M 7 Each independently is one or more of transition metal cations, 0<u≤2，0<v≤1，0<w≤1，0<x<6. For example A is H + 、Li + 、Na + 、K + 、NH 4 + 、Rb + 、Cs + 、Fr + 、Be 2+ 、Mg 2+ 、Ca 2+ 、Sr 2+ 、Ba 2+ Ra (Ra) 2+ One or more of M 6 And M 7 Each independently is a cation of one or more transition metal elements of Ti, V, cr, mn, fe, co, ni, cu, zn, sn and W.
The modifying compound of each material can be doping modification and/or surface coating modification of the material.
According to some embodiments of the application, a binder may be further included in the positive electrode active material layer 5211. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluoroacrylate resin.
According to some embodiments of the present application, a conductive agent may be further included in the positive electrode active material layer 5211. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
The second aspect of the present application provides a method for preparing the positive electrode tab 521, comprising: forming a positive electrode active material layer 5211; a capacity compensation layer 5212 is formed on one side of the positive electrode active material layer 5211, the capacity compensation layer 5212 including a catalyst and a capacity compensator having an average particle diameter of 2 μm or less. Therefore, the capacity compensation layer 5212 prepared by the method provided by the application comprises the catalyst and the capacity compensation agent, the catalyst can reduce the decomposition activation energy of the capacity compensation agent, so that the active ions of the capacity compensation agent are easier to be separated out, and the decomposition potential of the capacity compensation agent is reduced. By setting the average particle diameter of the capacity compensator in the above range, the probability of contact between the catalyst and the capacity compensator can be increased, the reactive sites of the capacity compensator can be increased, the ion and electron transport capacity can be improved, the decomposition potential of the capacity compensator can be further reduced, the decomposition efficiency and the utilization rate of the capacity compensator can be improved, the capacity retention rate of the battery can be further improved, and the service life of the battery can be prolonged.
According to some embodiments of the application, the method of forming the capacity compensation layer 5212 further comprises: a catalyst layer is formed on one side of the positive electrode active material layer 5211, and the capacity compensator is formed in the catalyst layer by electrochemical deposition.
According to some embodiments of the application, forming the catalyst layer may be performed by mixing a catalyst, a binder, a conductive agent, and a solvent to form a slurry, and coating the slurry on the pole piece to form the catalyst layer.
According to some embodiments of the application, when the capacity compensator is Li 2 O or Li 2 O 2 When Li// O is used 2 In the principle of the battery, a positive electrode is a pole piece containing a positive electrode active material layer 5211 and a catalyst layer, and lithium metal is a negative electrode to form an electrochemical cell, and O 2 Under atmosphere, lead toOvershoot of different lower voltages to form Li 2 O or Li 2 O 2 Due to the presence of pores in the catalyst layer, li 2 O or Li 2 O 2 May enter the pores to form the capacity compensator in situ in the catalyst layer.
According to some embodiments of the application, when the capacity compensator is Li 2 CO 3 、Li 2 C 2 O 4 Or Li (lithium) 2 C 4 O 4 When Li// CO is utilized 2 In the principle of the battery, a positive electrode is a pole piece containing a positive electrode active material layer 5211 and a catalyst layer, and lithium metal is a negative electrode to form an electrochemical cell, and the electrochemical cell is formed by CO 2 In the atmosphere, li is formed by adjusting different lower limit voltages 2 CO 3 、Li 2 C 2 O 4 Or Li (lithium) 2 C 4 O 4 Due to the presence of pores in the catalyst layer, li 2 CO 3 、Li 2 C 2 O 4 Or Li (lithium) 2 C 4 O 4 May enter the pores to form the capacity compensator in situ in the catalyst layer.
According to some embodiments of the application, when the capacity compensator is Li 2 S, using Li// S cell principle, using pole piece containing positive electrode active material layer 5211 and catalyst layer as positive electrode, applying sulfur nano particles on catalyst layer, using lithium as negative electrode to assemble into electrochemical cell, forming Li under inert gas atmosphere 2 S, li due to the presence of pores in the catalyst layer 2 S may enter the pores to form the capacity compensator in situ in the catalyst layer.
According to some embodiments of the application, when the capacity compensator is Li 2 Se or Li 2 Se 2 When using the Li// Se battery principle, using a pole piece containing a positive electrode active material layer 5211 and a catalyst layer as a positive electrode, applying selenium nano particles on the catalyst layer, using lithium metal as a negative electrode to assemble an electrochemical cell, and forming Li by adjusting different lower limit voltages under inert gas atmosphere 2 Se or Li 2 Se 2 Due to the presence of pores in the catalyst layer, li 2 Se or Li 2 Se 2 May enter the pores to form in situ in the catalyst layerA volume compensation agent.
According to some embodiments of the present application, when the capacity compensator is LiF, using the Li// CF cell principle, a pole piece containing a positive electrode active material layer 5211 and a catalyst layer is used as a positive electrode, CF nanoparticles are applied on the catalyst layer, lithium metal is used as a negative electrode to assemble an electrochemical cell, liF is formed in an inert gas atmosphere, and LiF can enter the pores due to the existence of the catalyst layer to form the capacity compensator in situ in the catalyst layer.
Therefore, the electrochemical deposition can form the capacity compensator with smaller average grain diameter on the catalyst in situ, so that the probability of the contact between the catalyst and the capacity compensator is improved, the reaction site of the capacity compensator is increased, the transmission capacity of ions and electrons is improved, the decomposition potential of the capacity compensator is further reduced, the decomposition efficiency and the utilization rate of the capacity compensator are improved, the capacity retention rate of a battery is further improved, and the service life of the battery is prolonged.
According to some embodiments of the present application, when the capacity compensator is formed in situ on the catalyst by electrochemical deposition, the capacity compensator with different particle sizes can be obtained by adjusting the current.
According to some embodiments of the application, the porosity of the catalyst layer may be 30% -70%, for example, 30%, 40%, 50%, 60% or 70%, etc., or may be in the range of any of the numerical compositions described above. Therefore, the efficiency of in-situ deposition of the capacity compensator on the surface of the catalyst is improved in the electrochemical deposition process, the probability of contact between the catalyst and the capacity compensator is improved, the decomposition potential of the capacity compensator is reduced, and the decomposition efficiency and the utilization rate of the capacity compensator are improved. According to some embodiments of the application, the catalyst layer may have a porosity of 30% to 50%.
In the present application, the porosity of the catalyst layer was measured using a full-automatic gas displacement method true density meter AccuPyc II 1340. Taking 10 positive pole pieces with consistent thickness D and area S, placing the positive pole pieces in a density tester, introducing helium or nitrogen into the density tester according to a program, starting testing, and obtaining the real volume V of a sample after the testing is finished 1 The method comprises the steps of carrying out a first treatment on the surface of the After the catalyst layers of the 10 pole pieces are scraped, the thickness D of the pole piece is recorded 1 The mixture is placed in a density tester again to obtain the real volume V of the active material layer after the test 2 The apparent volume v=10×s× (D-D 1 ) True volume of catalyst layer V 3 =V 1 -V 2 The porosity of the catalyst layer is ((V-V) 3 ）/V）×100%。
A third aspect of the present application provides a battery comprising the positive electrode tab 521 provided in the first aspect of the present application or the positive electrode tab 521 prepared by the method provided in the second aspect of the present application. Thereby, the capacity retention rate of the battery is improved.
According to some embodiments of the present application, the battery further includes a negative electrode tab including a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector, the negative electrode active material layer including a negative electrode active material.
As an example, the anode current collector has two surfaces opposing in its own thickness direction, and the anode active material layer is provided on either one or both of the two surfaces opposing the anode current collector.
In some embodiments, the negative electrode current collector may employ a metal foil or a composite current collector. For example, as the metal foil, copper foil may be used. The composite current collector may include a polymeric material base layer and a metal layer formed on at least one surface of the polymeric material base material. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
In some embodiments, the anode active material may employ an anode active material for a battery, which is well known in the art. As an example, the anode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like. The silicon-based material may be at least one selected from elemental silicon, silicon oxygen compounds, silicon carbon composites, silicon nitrogen composites, and silicon alloys. The tin-based material may be at least one selected from elemental tin, tin oxide, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery anode active material may be used. These negative electrode active materials may be used alone or in combination of two or more.
In some embodiments, the anode active material layer further optionally includes a binder. The binder may be at least one selected from Styrene Butadiene Rubber (SBR), polyacrylic acid (PAA), sodium Polyacrylate (PAAs), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium Alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).
In some embodiments, the anode active material layer further optionally includes a conductive agent. The conductive agent is at least one selected from superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
In some embodiments, the anode active material layer may optionally further include other adjuvants, such as a thickener (e.g., sodium carboxymethyl cellulose (CMC-Na)), and the like.
In some embodiments, the negative electrode sheet may be prepared by: dispersing the above components for preparing the negative electrode sheet, such as a negative electrode active material, a conductive agent, a binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; and coating the negative electrode slurry on a negative electrode current collector, and obtaining a negative electrode plate after the procedures of drying, cold pressing and the like.
According to some embodiments of the application, an electrolyte is also included in the battery, the electrolyte acting to conduct ions between the positive electrode tab 521 and the negative electrode tab. The application is not particularly limited in the kind of electrolyte, and may be selected according to the need.
According to some embodiments of the application, the electrolyte is an electrolyte. The electrolyte includes an electrolyte salt and a solvent.
According to some embodiments of the application, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis-fluorosulfonyl imide, lithium bis-trifluoromethylsulfonyl imide, lithium trifluoromethylsulfonate, lithium difluorophosphate, lithium difluorooxalato borate, lithium difluorodioxaato phosphate, and lithium tetrafluorooxalato phosphate.
According to some embodiments of the application, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1, 4-butyrolactone, sulfolane, dimethylsulfone, methylsulfone, and diethylsulfone.
According to some embodiments of the application, the electrolyte further optionally includes an additive. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives capable of improving certain properties of the battery, such as additives that improve the overcharge performance of the battery, additives that improve the high or low temperature performance of the battery, and the like.
According to some embodiments of the present application, the battery further includes a separator, the kind of the separator is not particularly limited, and any known porous structure separator having good chemical and mechanical stability may be selected.
According to some embodiments of the application, the material of the isolating film may be at least one selected from glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film or a multilayer composite film, and is not particularly limited. When the separator is a multilayer composite film, the materials of the respective layers may be the same or different, and are not particularly limited.
According to some embodiments of the present application, the positive electrode tab 521, the negative electrode tab, and the separator may be manufactured into an electrode assembly through a winding process or a lamination process.
According to some embodiments of the application, the battery may include an outer package. The outer package may be used to encapsulate the electrode assembly and electrolyte described above.
According to some embodiments of the application, the exterior package of the battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, or the like. The outer package of the battery may also be a pouch, such as a pouch-type pouch. The material of the flexible bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.
The shape of the battery is not particularly limited in the present application, and may be cylindrical, square, or any other shape. For example, fig. 4 is a square-structured battery 5 as an example.
According to some embodiments of the application, referring to fig. 5, the outer package may include a housing 51 and a cover 53. The housing 51 may include a bottom plate and a side plate connected to the bottom plate, where the bottom plate and the side plate enclose a receiving chamber. The housing 51 has an opening communicating with the accommodation chamber, and the cover plate 53 can be provided to cover the opening to close the accommodation chamber. The positive electrode tab 521, the negative electrode tab, and the separator may be formed into the electrode assembly 52 through a winding process or a lamination process. The electrode assembly 52 is enclosed in the accommodating chamber. The electrolyte is impregnated in the electrode assembly 52. The number of electrode assemblies 52 included in the battery 5 may be one or more, and those skilled in the art may choose according to specific practical requirements.
According to some embodiments of the present application, the cells may be assembled into a battery module, and the number of cells contained in the battery module may be one or more, and the specific number may be selected by one skilled in the art according to the application and capacity of the battery module.
Fig. 6 is a battery module 4 as an example. Referring to fig. 6, in the battery module 4, a plurality of batteries 5 may be sequentially arranged in the longitudinal direction of the battery module 4. Of course, the arrangement may be performed in any other way. The plurality of batteries 5 may be further fixed by fasteners.
Alternatively, the battery module 4 may further include a housing having an accommodating space in which the plurality of batteries 5 are accommodated.
According to some embodiments of the present application, the battery modules may be assembled into a battery pack, and the number of battery modules included in the battery pack may be one or more, and a specific number may be selected by those skilled in the art according to the application and capacity of the battery pack.
Fig. 7 and 8 are battery packs 1 as an example. Referring to fig. 7 and 8, a battery case and a plurality of battery modules 4 disposed in the battery case may be included in the battery pack 1. The battery box includes an upper box body 2 and a lower box body 3, and the upper box body 2 can be covered on the lower box body 3 and forms a closed space for accommodating the battery module 4. The plurality of battery modules 4 may be arranged in the battery box in any manner.
A fourth aspect of the application provides a powered device comprising a battery provided in the third aspect of the application. Thereby, the lifetime of the consumer is increased.
The electric equipment comprises at least one of a battery, a battery module or a battery pack provided by the application. The battery, battery module or battery pack may be used as a power source for the powered device, and may also be used as an energy storage unit for the powered device. The powered device may include a mobile device (e.g., a cell phone, a notebook computer, etc.), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship, a satellite, an energy storage system, etc., but is not limited thereto.
As the electric device, a battery module, or a battery pack may be selected according to the use requirement thereof.
Fig. 9 is a powered device as an example. The electric equipment is a pure electric vehicle, a hybrid electric vehicle or a plug-in hybrid electric vehicle and the like. To meet the high power and high energy density requirements of the consumer on the battery, a battery pack or battery module may be employed.
The device as another example may be a cell phone, tablet computer, notebook computer, or the like. The device is typically required to be lightweight and slim, and may employ a battery as a power source.
In order to make the technical problems, technical schemes and beneficial effects solved by the embodiments of the present application more clear, the following will be described in further detail with reference to the embodiments and the accompanying drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses. All other embodiments, which can be made by a person skilled in the art based on the embodiments of the application without any inventive effort, are intended to fall within the scope of the application.
Example 1
1. Preparation of positive electrode sheet
The lithium iron phosphate material, the conductive agent carbon black and the binder polyvinylidene fluoride (PVDF) are mixed according to the weight ratio of 97:1: and 2, fully stirring and uniformly mixing the mixture in an N-methylpyrrolidone (NMP) solvent system to obtain first positive electrode slurry, uniformly coating the first positive electrode slurry on a positive electrode current collector, and drying to obtain the lithium iron phosphate layer pole piece.
Cobalt nitride catalyst, carbon nano tube and binder polyvinylidene fluoride (PVDF) are mixed according to the weight ratio of 85:10: and 5, fully stirring and uniformly mixing the mixture in an N-methyl pyrrolidone (NMP) solvent system to obtain second positive electrode slurry, uniformly coating the second positive electrode slurry on a lithium iron phosphate layer pole piece, drying, cold pressing and cutting for later use.
The pole piece is taken as a positive electrode, lithium metal is taken as a negative electrode to be assembled into an electrochemical cell, and saturated O 2 Under the atmosphere, the cell was discharged to 1.0V, the current density of the electrochemical deposition was 250mA/g, the time of the electrochemical deposition was 8h, and the current density was measured according to Li// O 2 Principle of Li 2 O is deposited in situ on the catalyst. And then taking out the positive pole piece in the electrochemical cell, and drying and secondarily cold-pressing to obtain the positive pole piece containing the lithium supplementing agent.
2. Preparation of negative electrode sheet
Active substances of artificial graphite, conductive agent carbon black, binder Styrene Butadiene Rubber (SBR) and thickener sodium carboxymethyl cellulose (CMC-Na) are mixed according to the weight ratio of 97.2:0.8:0.8:1.2, dissolving in deionized water serving as a solvent, and uniformly mixing to prepare negative electrode slurry; and uniformly coating the negative electrode slurry on a negative electrode current collector copper foil, and drying, cold pressing and cutting to obtain a negative electrode plate.
3. Isolation film
A polypropylene film was used as a separator.
4. Assembled battery
And sequentially stacking the obtained positive electrode plate, the isolating film and the negative electrode plate containing the lithium supplementing agent, enabling the isolating film to be positioned between the positive electrode plate and the negative electrode plate to play a role of isolation, then winding to obtain a bare cell, welding a tab for the bare cell, loading the bare cell into an aluminum shell, baking at 80 ℃ for removing water, injecting electrolyte, and sealing to obtain the uncharged battery. And the uncharged battery is subjected to the procedures of standing, hot and cold pressing, formation, shaping, capacity testing and the like in sequence to obtain the lithium ion battery.
The preparation methods of the batteries in example 2-example 23 and comparative examples 1 and 2 are the same as those in example 1, and the differences are shown in Table 1.
Example 6 Li 2 C 2 O 4 The electrochemical deposition process of (2) is as follows: lithium iron phosphate pole piece containing catalyst layer is used as positive electrode, lithium metal is used as negative electrode to assemble electrochemical cell, and saturated CO 2 Under the atmosphere, the cell was discharged to 1.0V, the current density of the electrochemical deposition was 250mA/g, the time of the electrochemical deposition was 8h, and the electrochemical deposition was carried out according to Li// CO 2 Principle of Li 2 C 2 O 4 In situ deposition on the catalyst. And then taking out the positive pole piece in the electrochemical cell, and drying and secondarily cold-pressing to obtain the positive pole piece containing the lithium supplementing agent.
Example 7 Li 2 The electrochemical deposition process of S is as follows: the lithium iron phosphate pole piece containing a catalyst layer is used as an anode, sulfur nano particles are applied to the catalyst layer, lithium metal is used as a cathode to be assembled into an electrochemical cell, the cell is discharged to 1.0V under nitrogen, the current density of electrochemical deposition is 400mA/g, the electrochemical deposition time is 5h, and Li is carried out according to the Li// S cell principle 2 S is deposited in situ on the catalyst. And then taking out the positive pole piece in the electrochemical cell, and drying and secondarily cold-pressing to obtain the positive pole piece containing the lithium supplementing agent.
The electrochemical deposition of LiF in example 8 is: and (3) taking a lithium iron phosphate pole piece containing a catalyst layer as an anode, applying CF nano particles on the catalyst layer, taking lithium metal as a cathode to assemble an electrochemical cell, discharging the cell to 1.0V under nitrogen, wherein the current density of electrochemical deposition is 500mA/g, the time of electrochemical deposition is 4 hours, and LiF is deposited on the catalyst in situ according to the Li// CF cell principle. And then taking out the positive pole piece in the electrochemical cell, and drying and secondarily cold-pressing to obtain the positive pole piece containing the lithium supplementing agent.
Comparative example 1 Li 2 The electrochemical deposition process of O is as follows: taking a lithium iron phosphate pole piece containing a catalyst layer as an anode, and in saturated O 2 Under the atmosphere, the cell was discharged to 1.0V, the current density of the electrochemical deposition was 2000mA/g, the time of the electrochemical deposition was 1h, and the electrochemical deposition was performed according to Li// O 2 Principle of Li 2 O is deposited in situ on the catalyst. And then taking out the positive pole piece in the electrochemical cell, and drying and secondarily cold-pressing to obtain the positive pole piece containing the lithium supplementing agent.
The preparation method of the positive electrode sheet in comparative example 2 comprises the following steps:
the lithium iron phosphate material, the conductive agent carbon black and the binder polyvinylidene fluoride (PVDF) are mixed according to the weight ratio of 97:1: and 2, fully stirring and uniformly mixing the mixture in an N-methylpyrrolidone (NMP) solvent system to obtain first positive electrode slurry, uniformly coating the first positive electrode slurry on a positive electrode current collector, and drying to obtain the lithium iron phosphate layer pole piece.
The pole piece is taken as a positive electrode, lithium metal is taken as a negative electrode to be assembled into an electrochemical cell, and saturated O 2 Under the atmosphere, the cell was discharged to 1.0V, the current density of the electrochemical deposition was 1000mA/g, the time of the electrochemical deposition was 2h, and the current density was measured according to Li// O 2 Principle of depositing Li on a lithium iron phosphate layer 2 O. And then taking out the positive pole piece in the electrochemical cell, and drying and secondarily cold-pressing to obtain the positive pole piece containing the lithium supplementing agent.
Performance testing
1. Battery capacity retention test
The battery capacity retention test procedure was as follows: the battery corresponding to example 1 was charged to 3.65V at a constant current of 1/3C, charged to 0.05C at a constant voltage of 3.65V, left to stand for 5min, discharged to a discharge cutoff voltage at 1/3C, and the obtained capacity was designated as initial capacity C 0 . Repeating the above steps for the same battery, and simultaneously recording the discharge capacity C of the battery after the nth cycle n Battery capacity retention rate P after each cycle n =C n /C 0 *100%. In this test procedure, the first cycle corresponds to n=1, the second cycle corresponds to n=2, and … … the 100 th cycle corresponds to n=100. The battery capacity retention rate data corresponding to example 1 in table 1 is data measured after 100 cycles under the above test conditions, i.e., P 100 Is a value of (2).
2. Lithium supplement agent decomposition voltage test
The batteries of examples and comparative examples were charged to 3.65V at a constant current of 1/3C, charged to 0.05C at a constant voltage of 3.65V, left for 5min, and then charged to 4.5V at an upper limit voltage at a constant current of 0.1C, and voltage (V) and capacity (Q) data obtained in the apparatus were recorded, and dQ/dV data was obtained by mathematical processing. And (3) drawing by taking the voltage data V as an abscissa axis and the corresponding dQ/dV as an ordinate axis, so as to obtain a dQ/dV curve changing along with V, wherein the voltage value corresponding to the position of the peak of the curve in the 3.65V-4.5V interval is the decomposition voltage of the lithium supplementing agent.
3. Average particle size test of Capacity Compensation agent and catalyst
The capacity compensator and the catalyst are distinguished by a FEI Talos FS200X transmission electron microscope and an X-ray energy spectrometer (EDS), specifically, 0.01g of capacity compensation layer powder is placed in the transmission electron microscope, and the magnification is adjusted to observe the sample so as to ensure that the sample is clear and the quantity is distinguishable. The capacity compensator and the catalyst can be distinguished from a specific metal element in the catalyst by EDS elemental analysis. And respectively counting the particle sizes (not less than 10 particles) of the capacity compensator and the catalyst particles, and obtaining the average particle sizes of the capacity compensator and the catalyst particles by taking the average value.
4. Capacity compensator and catalyst content testing
And testing by using a TGA-601 thermogravimetric analyzer. The thermal decomposition temperature of the catalyst is about 1000-2000 ℃, the thermal decomposition temperature of the capacity compensator is about 300-600 ℃, the capacity compensation layer on the positive pole piece is scraped off, nitrogen is introduced into a TGA-601 thermogravimetric analyzer to heat to 700-900 ℃, and the capacity compensator is decomposed and then separated to obtain the catalyst. Obtaining the content M of the capacity compensator by weight loss mass 2 The catalyst content is (100% -M) 2 ）。
5. Catalyst specific surface area test
The thermal decomposition temperature of the catalyst is about 1000-2000 ℃, the thermal decomposition temperature of the capacity compensator is about 300-600 ℃, the capacity compensation layer on the positive pole piece is scraped off, and the catalyst can be obtained after the capacity compensator is decomposed after being heated to 700-900 ℃. The BET specific surface area can be measured by referring to the following method: about 7g of the sample was put into a 9cc bulb-equipped long tube using a U.S. microphone multi-station type full-automatic specific surface area and pore analyzer GeminiVII2390, deaerated at 200 ℃ for 2 hours, and then put into a host computer for testing to obtain BET (specific surface area) data of the catalyst.
6. Positive electrode active material content test
The content of the positive electrode active material can be measured using a TGA-601 thermogravimetric analyzer. Scraping the capacity compensation layer and the active material layer on the positive electrode plate in sequence, placing the material of the active material layer in a thermogravimetric analyzer, introducing oxygen for heating, decomposing substances except the positive electrode active material in the material of the active material layer, and obtaining the content M of the substances except the positive electrode active material through weight loss 3 The content of the positive electrode active material is (100% -M) 3 ）。
The test results of the batteries in example 1-example 23 and comparative examples 1, 2 are shown in table 2.
Conclusion: as can be seen from table 2, the decomposition voltages of the capacity compensators of the batteries in examples 1 to 23 were lower than those of comparative examples 1 and 2, and the cyclic capacity retention rates of the batteries in examples 1 to 23 were higher than those of comparative examples 1 and 2, indicating that the present application can reduce the decomposition potential of the capacity compensator, improve the decomposition efficiency and the utilization of the capacity compensator, and thus improve the capacity retention rate of the battery and the life of the battery by reducing the average particle diameter of the capacity compensator.
Examples 1 to 5 show that the smaller the particle diameter of the capacity compensator, the lower the decomposition voltage of the capacity compensator, and the higher the cycle capacity retention rate of the battery.
Example 6-example 8 it can be seen that the different capacity compensators formed by different electrochemical deposition processes can reduce the decomposition voltage of the capacity compensator and increase the cycle capacity retention rate of the battery due to the smaller particle size of the capacity compensator.
It can be seen from examples 9 to 16 that the decomposition voltage of the capacity compensator can be reduced and the cycle capacity retention rate of the battery can be improved by adjusting the kind and average particle diameter of the catalyst.
It can be seen from examples 17 to 19 that the decomposition voltage of the capacity compensator can be reduced and the cycle capacity retention rate of the battery can be improved by adjusting the catalyst content and adjusting the ratio of the catalyst content to the capacity compensator content.
As can be seen from examples 20 to 23, by adjusting the content of the positive electrode active material and adjusting the ratio of the content of the capacity compensator to the content of the positive electrode active material, the decomposition voltage of the capacity compensator can be reduced and the cycle capacity retention rate of the battery can be improved.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the application, and are intended to be included within the scope of the appended claims and description. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions falling within the scope of the claims.

Claims (22)

1. A positive electrode sheet, characterized by comprising:
a positive electrode active material layer including a positive electrode active material;
and a capacity compensation layer provided on one side of the positive electrode active material layer, the capacity compensation layer including a catalyst and a capacity compensator having an average particle diameter of less than or equal to 2 μm.
2. The positive electrode sheet according to claim 1, wherein the average particle diameter of the capacity compensator is 50nm to 2 μm.
3. The positive electrode sheet according to claim 2, wherein the average particle diameter of the capacity compensator is 50nm to 500nm.
4. A positive electrode sheet according to any one of claims 1 to 3, wherein the average particle diameter of the catalyst is less than or equal to the average particle diameter of the capacity compensator.
5. The positive electrode sheet according to claim 4, wherein the catalyst has an average particle diameter of 50nm to 2 μm.
6. The positive electrode sheet according to claim 5, wherein the catalyst has an average particle diameter of 50nm to 500nm.
7. The positive electrode sheet according to claim 4Characterized in that the BET specific surface area of the catalyst is 87m 2 /g-200m 2 /g。
8. The positive electrode sheet according to claim 7, wherein the catalyst has a BET specific surface area of 130m 2 /g-200m 2 /g。
9. The positive electrode sheet according to claim 4, wherein a ratio of the mass of the catalyst to the mass of the capacity compensator is (5-40) based on the total mass of the capacity compensation layer: 100.
10. the positive electrode sheet according to claim 4, wherein a ratio of the mass of the capacity compensator to the mass of the positive electrode active material is (0.5-20) based on the total mass of the positive electrode sheet: 100.
11. the positive electrode sheet according to claim 4, wherein the catalyst comprises a metal compound.
12. The positive electrode sheet according to claim 11, wherein at least part of the surface of the metal compound has a carbon coating layer.
13. The positive electrode sheet according to claim 12, wherein the carbon coating layer has a mass ratio of 5% to 30% based on the total mass of the metal compound and the carbon coating layer.
14. The positive electrode sheet according to claim 11, wherein the metal compound comprises at least one of a transition metal oxide, a transition metal carbide, a transition metal nitride, a transition metal sulfide, or a transition metal phosphide.
15. The positive electrode sheet according to claim 4, wherein the capacity compensator comprises a lithium supplementing agent andand/or a sodium supplementing agent, wherein the lithium supplementing agent comprises Li 2 O、Li 2 O 2 、Li 2 CO 3 、Li 2 C 2 O 4 、Li 2 C 4 O 4 、Li 2 S、Li 2 Se、Li 2 Se 2 Or LiF; the sodium supplementing agent comprises Na 2 O、Na 2 O 2 、Na 2 CO 3 、Na 2 C 2 O 4 、Na 2 C 4 O 4 、Na 2 S、Na 2 Se、Na 2 Se 2 Or NaF.
16. The positive electrode sheet according to claim 4, further comprising: and the capacity compensation layer is positioned on one side of the positive electrode active material layer away from the positive electrode current collector.
17. The preparation method of the positive electrode plate is characterized by comprising the following steps:
forming a positive electrode active material layer including a positive electrode active material;
and forming a capacity compensation layer on one side of the positive electrode active material layer, the capacity compensation layer including a catalyst and a capacity compensator having an average particle diameter of less than or equal to 2 μm.
18. The method of claim 17, wherein the method of forming the capacity compensation layer further comprises: a catalyst layer is formed on one side of the positive electrode active material layer, and the capacity compensator is formed in the catalyst layer by an electrochemical deposition method.
19. The method of claim 18, wherein the catalyst layer has a porosity of 30% -70%.
20. The method of claim 19, wherein the catalyst layer has a porosity of 30% -50%.
21. A battery comprising the positive electrode sheet of any one of claims 1-16 or the positive electrode sheet prepared by the method of any one of claims 17-20.
22. A powered device comprising the battery of claim 21.
CN202311409281.1A 2023-10-27 2023-10-27 Positive electrode plate, preparation method thereof, battery and electric equipment Pending CN117133862A (en)

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