CN115881960A - Positive electrode additive, preparation method and application thereof, secondary battery and terminal equipment - Google Patents

Positive electrode additive, preparation method and application thereof, secondary battery and terminal equipment Download PDF

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Publication number
CN115881960A
CN115881960A CN202111165759.1A CN202111165759A CN115881960A CN 115881960 A CN115881960 A CN 115881960A CN 202111165759 A CN202111165759 A CN 202111165759A CN 115881960 A CN115881960 A CN 115881960A
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China
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positive electrode
alkali metal
electrode additive
particles
additive
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CN202111165759.1A
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李硕宇
夏圣安
谢封超
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Huawei Technologies Co Ltd
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Huawei Technologies Co Ltd
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Priority to CN202111165759.1A priority Critical patent/CN115881960A/en
Priority to PCT/CN2022/123116 priority patent/WO2023051760A1/en
Publication of CN115881960A publication Critical patent/CN115881960A/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
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • 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
    • 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
    • H01M4/04—Processes of manufacture in general
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The application provides a positive electrode additive, a preparation method and application thereof, a secondary battery and terminal equipment, wherein the positive electrode additive comprises secondary particles, the secondary particles comprise at least two kinds of primary particles, at least one kind of primary particles in the primary particles are alkali metal-rich materials, and at least one kind of primary particles are electronic conductive agents; in the molecular formula of the alkali metal-rich material, the molecular weight of the alkali metal element accounts for more than 10% of the total molecular weight of the alkali metal-rich material; wherein the gap between adjacent primary particles is less than or equal to 500nm. The cycle life and energy density of the secondary battery can be improved by utilizing the anode additive, and the cycle expansion of the battery core is relieved.

Description

Positive electrode additive, preparation method and application thereof, secondary battery and terminal equipment
Technical Field
The application relates to the field of batteries, in particular to a positive electrode additive, a preparation method and application thereof, a secondary battery and terminal equipment.
Background
With the vigorous development of large-scale energy storage industries such as consumer electronics, electric vehicles, and data centers, the market demand for the cycle life and energy density of secondary batteries is increasing. Taking a lithium ion battery with a silicon-based material as a negative electrode as an example, the lithium ion battery has gradually become a hot point of research due to higher theoretical energy density. However, in the lithium ion battery, a large amount of active lithium is consumed in the first charging process, and a large amount of active lithium is also consumed in the SEI film which is repeatedly broken and recombined and by-products thereof in the charging and discharging cycle process, so that the first coulombic efficiency and the cycle life of the lithium ion battery are low, and the energy density of the lithium ion battery is also affected due to the consumption of the active lithium, so that the cycle life and the energy density of the lithium ion battery need to be improved by introducing additional active lithium into the positive active material through a lithium supplement technology. In the lithium supplement technology, the lithium supplement of the cathode is high in safety risk and very strict in requirements on the processing environment, so that the lithium supplement of the anode is mainly used at present. In the process of lithium supplement of the positive electrode, the existing lithium supplement capacity is low, and after lithium supplement, the energy density and the cycle performance improvement degree are poor, so that the use requirement cannot be met.
Disclosure of Invention
The application provides a positive electrode additive, a preparation method and application thereof, a secondary battery and terminal equipment, so as to improve the supplement effect of positive electrode active ions and further improve the cycle life and energy density of the secondary battery.
In a first aspect, the present application provides a positive electrode additive for a secondary battery, the secondary particles including at least two kinds of primary particles, at least one of the primary particles being an alkali metal-rich material, at least one of the primary particles being an electron conductive agent, and a molecular weight of an alkali metal element in a molecular formula of the alkali metal-rich material being 10% or more of a total molecular weight of the alkali metal-rich material; wherein the gap between adjacent primary particles is less than or equal to 500nm.
The positive electrode additive comprises secondary particles, wherein at least two kinds of primary particles are contained in any one secondary particle, at least one kind of primary particles is an alkali metal-rich material, and at least one kind of primary particles is an electron conductive agent. The inside of the secondary particles is in a compact compaction structure, and the internal gaps of the secondary particles, namely the gaps among the primary particles, are controlled within the range of 500nm, so that the transmission impedance among alkali-rich metal materials can be remarkably reduced, and the transmission of positive active ions in the secondary particles is improved, therefore, in the charge-discharge cycle process of a secondary battery, the supplement effect of the positive active ions can be remarkably improved. Furthermore, when the internal gap of the secondary particle is less than or equal to 500nm, the anode additive is applied to the anode material of the secondary battery, so that the conduction rate of the active ions of the anode can be obviously improved, and the cycle life and the energy density of the secondary battery are improved. In addition, by controlling the internal gap of the secondary particles to be below 500nm, a stable space network structure can be formed by using the electronic conductive agent, so that the effect of relieving the circular expansion of the battery core is achieved.
The alkali metal in the present application comprises at least one of lithium, sodium and potassium.
In an optional implementation manner of the present application, a gap between adjacent primary particles is less than or equal to 300nm, so as to further improve a conduction rate of positive active ions, improve a cycle life and an energy density of a secondary battery, and reduce a cycle expansion rate of a battery cell.
In an alternative embodiment of the present application, the alkali-rich material has an area ratio of 50% to 90% in at least a cross-sectional area of 5 μm × 5 μm. In a preferred embodiment, the area ratio of the alkali metal-rich material is 50% to 90% in any cross-sectional range of 5 μm × 5 μm. Wherein the alkali metal-rich material can decompose at a certain voltage to form positive active ions, such as active lithium, active sodium or active potassium, and the catalyst is used to lower the decomposition potential of the alkali metal-rich material. The area ratio of the alkali-rich metal material is limited in the range, and the supplementary effect of the active ions of the positive electrode can be effectively improved.
In an alternative implementation manner of the present application, the mass ratio of the alkali-rich metal material in the positive electrode additive is 10-70%.
In an alternative embodiment of the present application, the secondary particles further comprise a catalyst, and the catalyst is present in an area of 5% to 95% in at least one cross-sectional area of 5 μm × 5 μm in the secondary particles. In a preferred embodiment, the catalyst area is 5% to 95% in any cross-sectional area of 5. Mu. M.times.5. Mu.m. Wherein, when the positive electrode additive exists in the form of raw material, or the positive electrode additive is applied to the secondary battery and before the secondary battery is formed, the area of the catalyst is 5-50%, preferably 10-40% in any section range of 5 μm × 5 μm in the secondary particles of the positive electrode additive; after the secondary battery is formed, the area of the catalyst accounts for 50-95%, preferably 55-80% of the secondary particles of the positive electrode additive within the section range of any 5 micrometers multiplied by 5 micrometers. The area ratio of the catalyst is limited to the above range, and the decomposition of the alkali metal-rich material can be effectively promoted to generate more positive active ions, such as lithium ions, sodium ions or potassium ions.
In an alternative implementation manner of the present application, in the secondary particles, the density of the catalyst is greater than that of the alkali metal-rich material, and the density of the alkali metal-rich material is greater than that of the electron conductive agent, so as to better improve the conduction effect.
In an alternative embodiment of the present application, the mass ratio of the catalyst in the positive electrode additive is 30 to 90%.
In an optional implementation manner of the present application, the mass ratio of the electronic conductive agent in the positive electrode additive is 0.1-5%.
In an alternative implementation manner of the present application, the electronic conductive agent is a linear structure and/or a planar structure, and when the electronic conductive agent is a linear structure, the distance D1 between the two farthest points of the linear structure is greater than the sum of the particle diameter D2 of the alkali metal-rich material and the particle diameter D3 of the catalyst; when the electronic conductive agent is a planar structure, the distance D1 between the two farthest points of the planar structure is larger than the sum of the particle diameter D2 of the alkali metal-rich material and the particle diameter D3 of the catalyst. The electronic conductive agent with a linear structure or a surface structure is adopted, so that the electronic conductive agent can be inserted into the secondary particles to form an electronic conductive network, and the conductivity of the secondary particles is improved. It is understood that the electron conductive agent may include a granular electron conductive agent in addition to at least an electron conductive agent of a linear structure or a planar structure.
In an optional implementation manner of the present application, D1, D2, and D3 satisfy: 1 is formed by the woven fabrics D1/(D2 + D3) and is less than or equal to 50. Wherein D2 and D3 may satisfy: d2<1/2D3. So as to further improve the contact between the alkali metal-rich material and the catalyst and the electron conductive agent and improve the conductivity of the secondary particles.
In an alternative implementation of the present application, the catalyst has a particle size of 50nm to 500nm. The nanometer particle size can improve the specific surface area of the catalyst and increase the contact area of the catalyst, the alkali-rich metal material and the electronic conductive agent.
In an alternative implementation of the present application, the electron conductive agent includes at least one of carbon nanotubes, carbon nanofibers, graphite, or graphene.
In an alternative implementation of the present application, the alkali-metal-rich material comprises at least one of an alkali metal oxide, an alkali metal superoxide, an alkali metal peroxide, an alkali metal sulfide, or an alkali metal salt; wherein the alkali metal salt comprises an alkali metal carbonate, an alkali metal oxalate or an alkali metal silicate.
The alkali metal is exemplified by lithium, and the alkali metal-rich material is a lithium-rich material comprising at least one of doped or undoped lithium oxide, doped or undoped lithium peroxide, doped or undoped lithium superoxide, doped or undoped lithium sulfide, or a lithium salt. Wherein, the inorganic lithium salt includes but is not limited to one of lithium carbonate, lithium oxalate or lithium silicate.
The alkali metal is exemplified by sodium, and the alkali metal-rich material is a sodium-rich material, the sodium-rich material comprises at least one of sodium oxide, sodium sulfide or sodium salt, and the sodium oxide can be doped or undoped sodium oxide; wherein the sodium oxide comprises sodium oxide, sodium peroxide, or sodium superoxide; the sodium salt includes sodium carbonate, sodium oxalate, sodium hydrosulfite, sodium silicate, etc.
The alkali metal is potassium, and the alkali metal-rich material is potassium-rich material, the potassium-rich material comprises potassium oxide or potassium salt, the potassium oxide comprises at least one of potassium oxide, potassium peroxide or potassium superoxide, and the potassium salt comprises potassium carbonate and/or potassium oxalate and/or potassium silicate.
In an alternative implementation of the present application, the catalyst includes at least one of elemental transition metal, transition metal carbide, transition metal oxide, transition metal sulfide, or transition metal lithium oxide. Wherein, the transition metal simple substance includes but is not limited to at least one of iron, cobalt, nickel, manganese, ruthenium, tungsten, iridium, platinum, molybdenum or titanium; transition metal carbides include, but are not limited to, at least one of iron carbide, cobalt carbide, nickel carbide, manganese carbide, ruthenium carbide, tungsten carbide, platinum-carbon composite, cobalt-carbon composite, iron-carbon composite, nickel-carbon composite, manganese-carbon composite, or ruthenium-carbon composite; transition metal oxides include, but are not limited to, at least one of iron oxide, cobalt oxide, nickel oxide, manganese oxide, ruthenium oxide, tungsten oxide, iridium oxide, or molybdenum oxide; transition metal sulfides include, but are not limited to, at least one of iron sulfide, fluidized cobalt, nickel sulfide, manganese sulfide, ruthenium sulfide, or molybdenum sulfide; the transition metal lithium oxide includes, but is not limited to, one of lithium cobaltate, lithium nickelate, lithium manganate, lithium nickel cobaltate, lithium nickel manganate or lithium nickel cobalt manganate. In an alternative implementation of the present application, the catalyst is selected from the group consisting of lithium cobaltate, NCM811, transition metal oxides, transition metal carbides, lithium cobaltate used as a catalyst having a diffraction peak intensity of the 006 crystal plane larger than that of the other crystal planes in XRD test. The raw materials are selected, so that byproducts can be avoided, the occupied space and the weight ratio of decomposition products in the anode material are reduced, and the energy density of the secondary battery is improved.
In an alternative implementation of the present application, the surface of the secondary particles is coated with a passivation layer.
In the data of the above possible implementations of the present application, for example, the internal voids and the cross-sectional area of the secondary particles, the area ratio and the mass ratio of the catalyst, the area ratio and the mass ratio of the alkali-rich material, and the particle diameter of each material particle, the values within the error range of engineering measurement should be understood as being within the range defined in the present application.
In a second aspect, the present application also provides a method for preparing a positive electrode additive, the method comprising: and (3) compacting and granulating the primary particles of the raw materials to form secondary particles, wherein the internal gaps of the formed secondary particles are less than or equal to 500nm.
The positive electrode additive obtained by the preparation method has the same technical effects as the positive electrode additive of the first aspect, and is not described again here.
In one possible implementation of the present application, the compacting and granulating of the primary particles of the raw material comprises: compacting and granulating a mixed raw material of primary particles containing an alkali-rich metal material, an electronic conductive agent and a catalyst to form secondary particles; or, the mixed raw material of the primary particles containing the alkali metal-rich material, the electron conductive agent and the catalyst precursor is compacted and granulated to form secondary particles. The catalyst may be added in the form of a catalyst, or may be added in the form of a catalyst precursor.
In one possible implementation of the present application, the primary particles of the alkali-metal-rich material and the primary particles of the catalyst are both nanoparticles.
In a third aspect, the present application provides the use of a positive electrode additive of the first aspect, which can be used in the manufacture of a secondary battery.
In a fourth aspect, the present application further provides a secondary battery, including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte, the electrolyte infiltrating the separator; the positive electrode comprises a positive electrode current collector and a positive electrode material layer, wherein the positive electrode material layer is mainly prepared from a positive electrode active material and the positive electrode additive of the first aspect of the application. Wherein the mass percentage of the positive electrode additive in the positive electrode material layer is 0.1-10%.
In a fifth aspect, the present application also provides a terminal device comprising an electric element and the secondary battery of the fourth aspect, wherein the secondary battery is electrically connected to the electric element to supply electric power to the electric element.
The terminal device includes, but is not limited to, a consumer product, a vehicle, a communication device, a base station, and the like, and specifically, the terminal device may be, for example, a mobile phone, a computer, a watch, a mobile power supply, an electric vehicle, a communication base station, and the like.
It is understood that the terminal device may further include a case in which both the electric element and the secondary battery are disposed, in addition to the electric element and the secondary battery.
Technical effects that can be achieved by the third aspect to the fifth aspect may be described with reference to corresponding effects in the first aspect, and are not repeated herein.
Drawings
Fig. 1 is a schematic structural view of a secondary particle according to an embodiment of the present application.
Reference numerals: 10-a lithium rich material; 20-an electron conductive agent; 30-a catalyst; 40-passivation layer.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more clear, the present application will be further described in detail with reference to the accompanying drawings.
The secondary battery mainly relies on the reversible deintercalation of active ions, such as lithium, sodium and potassium, to provide energy, so the amount of the active ions directly limits the energy density of the secondary battery, and the continuous loss of the active ions in the circulating process also leads to the reduction of the cycle life of the secondary battery. Taking the lithium secondary battery with silicon-based cathode as an example, the theoretical capacity of the silicon-based cathode can be as high as 4200mAh/g, so the secondary battery with silicon-based cathode has become the focus of current research. However, since the silicon-based material consumes a part of active lithium during the first charge and a part of active lithium is consumed by the SEI film that is repeatedly broken and reformed during charge and discharge cycles, the first efficiency and cycle life of such secondary batteries are poor.
In order to improve the first efficiency and cycle life of a secondary battery with a negative electrode containing silicon, hard carbon, phosphorus, tin and the like, the embodiment of the application provides the positive electrode additive, and the positive electrode additive is added into a positive electrode active material to supplement positive electrode active ions consumed in the process, so that the secondary battery obtains higher first efficiency and cycle life. The terminology used in the following examples is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of this application and the appended claims, the singular forms "a", "an", "the", and "the" are intended to include the plural forms as well, such as "one or more", unless the context clearly indicates otherwise.
Reference throughout this specification to "one embodiment" or "some embodiments," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," or the like, in various places throughout this specification are not necessarily all referring to the same embodiment, but rather "one or more but not all embodiments" unless specifically stated otherwise. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless expressly specified otherwise.
In an embodiment of the present application, fig. 1 is a schematic structural diagram of a secondary particle in an embodiment of the present application, and as shown in fig. 1, in an embodiment of the present application, the secondary particle includes a plurality of primary particles agglomerated together, and the types of the plurality of primary particles are at least two, where at least one of the primary particles is an alkali-rich material, and at least one of the primary particles is an electron conductive agent. Wherein the gap formed between adjacent primary particles is 500nm or less, preferably 300nm or less. It is understood that the voids between adjacent primary particles may be understood as internal voids of the secondary particles, i.e., the internal voids of the secondary particles are 500nm or less. By way of illustration, the internal voids of the secondary particles may be, for example, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 200nm, 300nm, 400nm, or 500nm. The positive electrode additive provided by the embodiment of the application is verified through a large number of experiments, when the internal gap of the secondary particles is within 500nm, and further when the internal gap of the secondary particles is within 300nm, the supplementary effect of positive active ions can be remarkably improved.
Referring to fig. 1, in one embodiment of the present application, the secondary particles include an alkali-metal-rich material 10, an electron conductive agent 20, and a catalyst 30, and are mainly formed of primary particles of the alkali-metal-rich material 10, the electron conductive agent 20, and the catalyst 30. It is to be understood that a plurality of alkali metal rich material particles, a plurality of electron conductive agent particles, and a plurality of catalyst particles may be included in any one secondary particle. The alkali-rich material 10 is decomposed under the action of a catalyst in the formation process of the secondary battery, and is used for generating positive active ions so as to supply the positive active ions. Wherein, in one embodiment of the present application, the density of the catalyst 30 is greater than the density of the alkali-rich material 10, and the density of the alkali-rich material 10 is greater than the density of the electron conductive agent 20.
Alkali metal-rich materials
The alkali metal-rich material in the embodiments of the present application means that, in the molecular formula of the alkali metal-rich material, the molecular weight of the alkali metal element accounts for more than 10% of the total molecular weight of the alkali metal-rich material. As an illustrative example, the alkali metal-rich material may be at least one of a non-metallic lithium compound, a non-metallic sodium compound, a non-metallic potassium compound, a multi-metallic lithium compound, a multi-metallic sodium compound, a multi-metallic potassium compound, an inorganic lithium salt, an inorganic sodium salt, an inorganic potassium salt, or an organic lithium, organic sodium salt, or organic potassium salt.
By way of illustration, the non-metallic lithium compound can be, for example, lithium oxide including, but not limited to, lithium oxide, lithium peroxide, lithium superoxide, and the like, and other non-metallic lithium compounds including, but not limited to, lithium fluoride, lithium chloride, lithium iodide, lithium bromide, lithium nitride, lithium sulfide, lithium phosphide, lithium arsenide, and the like.
The non-metallic sodium compound can be, for example, a sodium oxide compound including, but not limited to, sodium oxide, sodium peroxide, or sodium superoxide, among others, and other non-metallic sodium compounds including, but not limited to, sodium fluoride, sodium chloride, sodium iodide, sodium bromide, sodium nitride, sodium sulfide, sodium phosphide, or sodium arsenide, among others.
The non-metallic potassium compound can be, for example, potassium oxide compounds including but not limited to potassium oxide, potassium peroxide, or potassium superoxide, and the like, and other non-metallic potassium compounds including but not limited to potassium fluoride, potassium chloride, potassium iodide, potassium bromide, potassium nitride, potassium sulfide, potassium phosphide, or potassium arsenide, and the like.
The multi-element lithium metal compound includes, but is not limited to, lithium nickel oxide, lithium cobalt oxide, lithium iron oxide, lithium manganese oxide, lithium titanium oxide, lithium vanadium oxide, lithium zirconium oxide, or lithium molybdenum oxide.
The multi-metal sodium compound generally contains oxygen and sodium, and at least one transition metal element, such as sodium nickelate, sodium nickel manganese oxide, sodium copper iron manganese oxide, and the like.
The sodium polymetallic compound generally contains oxygen and potassium elements, and at least one transition metal element, such as potassium nickelate, potassium cupronickel, and the like.
Inorganic lithium salts include, but are not limited to, lithium carbonate, lithium phosphate, lithium sulfate, lithium silicate, lithium oxalate; the organic lithium salt may be, for example, lithium polyacrylate. Inorganic sodium salts include, but are not limited to, sodium carbonate, sodium phosphate, sodium sulfate, sodium silicate, sodium oxalate. Inorganic lithium salts include, but are not limited to, potassium carbonate, potassium phosphate, potassium sulfate, potassium silicate, potassium oxalate.
In one embodiment of the present application, taking a lithium ion battery as an example, the lithium-rich material may be selected from at least one of lithium oxide, lithium peroxide, lithium superoxide, lithium carbonate, or lithium oxalate. When the lithium-rich material is selected from at least one of the materials, the lithium-rich material only generates active lithium and gas in the formation process of the lithium ion battery, so that the decomposition residue of the lithium-rich material can be effectively reduced, and the energy density of the lithium ion battery is improved. In addition, only active lithium and gas are generated by the decomposition of the lithium-rich material, and the side reaction between residues and electrolyte can be further avoided, so that the safety performance and the cycle performance of the lithium ion battery are improved. In the sodium ion battery and the potassium ion battery, the lithium oxide, the lithium peroxide, the lithium superoxide, the lithium carbonate and the lithium oxalate are correspondingly replaced, and the same effect can be generated, and the repeated description is omitted.
In one embodiment of the present application, the alkali metal-rich material is present in an area ratio of 50% to 90% in any 5 μm × 5 μm cross-sectional area in the secondary particles. This improves the effect of supplementing the positive electrode active ions of the secondary battery. The area ratio of the alkali-rich material may be, for example, but not limited to: 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%, and ranges between any two of the foregoing.
In one embodiment of the present application, the ratio of the alkali-rich material to the positive electrode additive is 10 to 70% by mass, preferably 20 to 70% by mass, and more preferably 50 to 70% by mass, and may be, for example, 10%, 15%, 20%, 25%, 30%, 40%, 50%, 60%, 65% or 70% by mass.
Catalyst and process for preparing same
In one example of the present application, when the positive electrode additive is present as a raw material or before a chemical conversion treatment is not performed in the secondary battery, the catalyst is present in an area of 5% to 50% in any cross-sectional range of 5 μm × 5 μm in the secondary particles. This improves the effect of supplementing the positive electrode active ions. The area ratio of the catalyst can be, for example, typically but not limitatively: 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%, and ranges between any two of the foregoing.
In one embodiment of the present application, when the positive electrode additive is in a secondary battery and subjected to a chemical conversion treatment, the area of the catalyst in the secondary particles is 50% to 95% in any 5 μm × 5 μm cross-sectional range.
In one embodiment of the present application, the catalyst may be selected from transition metal carbides, transition metal oxides, transition metal sulfides, and the like, such as carbides, oxides, and the like of iron, cobalt, nickel, manganese, ruthenium, tungsten, iridium, platinum, molybdenum, titanium, and the like, and specifically may be iron carbide, cobalt carbide, nickel carbide, manganese carbide, ruthenium carbide, tungsten carbide, iron oxide, cobalt oxide, nickel oxide, manganese oxide, ruthenium oxide, tungsten oxide, iridium oxide, molybdenum oxide, iron sulfide, fluidized cobalt, nickel sulfide, manganese sulfide, ruthenium sulfide, molybdenum sulfide, and the like. The catalyst can also be transition metal simple substance or transition metal simple substance composite material, such as metal simple substances of iron, cobalt, nickel, manganese, ruthenium, tungsten, iridium, platinum, molybdenum, titanium and the like, platinum-carbon composite material, cobalt-carbon composite material, iron-carbon composite material, nickel-carbon composite material, manganese-carbon composite material and ruthenium-carbon composite material. The catalyst may also be a lithium transition metal oxide, such as lithium cobaltate, lithium nickelate, lithium manganate, lithium nickel cobaltate, lithium nickel manganate, lithium nickel cobalt manganate. In addition to this, the catalyst may also be a carbon material in sp2 hybridized form, such as graphite, graphene, carbon nanotubes, carbon spheres, and the like.
In one embodiment of the present application, the catalyst may be selected from lithium cobaltate, which has the following characteristics: when the diffraction pattern of the 006 crystal face is tested by XRD, the peak is the strongest peak.
The catalyst is used for reducing the decomposition potential of the alkali-rich metal material, and the decomposition voltage of the alkali-rich metal material is reduced and the decomposition of the alkali-rich metal material is promoted in the formation process of the secondary battery.
In one embodiment of the present application, the mass ratio of the catalyst in the positive electrode additive is 30% to 90%. The mass ratio of the catalyst in the positive electrode additive is 30 to 90%, preferably 30 to 80%, more preferably 30 to 70%, and may be, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%.
Electronic conductive agent
In one embodiment of the present application, the electron conductive agent is a linear structure and/or a planar structure, wherein the distance D1 between the two farthest points of the electron conductive agent of the linear structure is greater than the sum of the particle diameter D2 of the alkali metal-rich material and the particle diameter D3 of the catalyst; the distance D1 between the two farthest points of the electron conductive agent of the planar structure is larger than the sum of the particle diameter D2 of the alkali metal-rich material and the particle diameter D3 of the catalyst, namely D1 (D2 + D3). The electron conductive agent may be, for example, one of carbon nanotubes, carbon nanofibers, or graphene. In the structure, the electronic conductive agent is inserted in the secondary particles to form a conductive framework structure and form a good electronic conduction channel.
In one embodiment of the present application, the mass ratio of the electron conductive agent in the positive electrode additive is 0.1 to 5%. The added electronic conductive agent can enable the electronic conductive agent to form a three-dimensional skeleton structure in secondary particles of the positive electrode additive, and the electronic conductive agent is prevented from agglomerating on the surface of the alkali-rich metal material.
In one embodiment of the present application, D1, D2, and D3 satisfy: 1< -D1/(D2 + D3) < 50. In further embodiments of the present application, D2 and D3 satisfy: d2<1/2D3. The particle size of the catalyst may be, for example, 50nm to 500nm.
In one embodiment of the present application, the secondary particles may further include an ion conductive agent, wherein the ion conductive agent may be, for example, an inorganic electrolyte, an organic polymer electrolyte, or an organic-inorganic composite electrolyte.
Wherein, the inorganic electrolyte includes but is not limited to LiPON, lithium lanthanum zirconium oxygen, lithium lanthanum titanium oxygen, lithium aluminum titanium phosphate, lithium sulfur phosphorus iodine. The organic polymer electrolyte includes, but is not limited to, lithium polyacrylate, PEO-based solid electrolyte, PAN, PMMA electrolyte, and the like. The organic-inorganic composite electrolyte may be a composite of the above-exemplified inorganic electrolyte and organic polymer electrolyte.
With continued reference to fig. 1, in an embodiment of the present application, the powder particle of the positive electrode additive further includes a passivation layer 40, and the passivation layer 40 covers the surface of the secondary particle. The material forming the passivation layer 40 may be, for example, a carbon material, aluminum oxide, magnesium oxide, titanium nitride, lithium phosphate, lithium carbonate, lithium fluoride, lithium aluminum titanium phosphate, lithium lanthanum zirconium oxide, or an organic polymer. By providing the passivation layer 40, the interface of the secondary particles can be stabilized, and the transport ability of ions can be improved.
The following description will be made of a specific process for preparing the above-described positive electrode additive.
In an embodiment of the present application, a method for preparing a positive electrode additive of the embodiment of the present application includes: and (3) compacting and granulating the primary particles of the raw materials to form secondary particles. The internal gap of the secondary particles formed by compaction and granulation is less than or equal to 100nm.
In one embodiment of the present application, the primary particles of the feedstock are compacted and granulated, comprising: the mixed raw material of the primary particles containing the alkali-rich material, the electron conductive agent and the catalyst is compacted and granulated to form secondary particles.
Wherein, the alkali metal-rich material, the electronic conductive agent and the catalyst can be mixed by a ball milling mode. In one embodiment of the present application, before mixing the raw materials, the alkali-rich material and the primary particles of the catalyst may be subjected to ball milling and pulverization, so as to make the primary particles of the alkali-rich material and the primary particles of the catalyst nano-sized, increase the specific surface area of the alkali-rich material and the catalyst, and increase the solid-solid contact area between the alkali-rich material and the catalyst. As an illustrative example, the alkali metal-rich material and the catalyst may be first subjected to ball milling to perform nanocrystallization on the primary particles of the alkali metal-rich material and the catalyst.
In one embodiment of the present application, the step of mixing the alkali-rich material, the electron conductive agent, and the catalyst comprises: firstly, carrying out ball milling on an alkali-rich metal material and a catalyst for 8-72 h, then adding a powder material or an oily dispersion liquid of an electronic conductive agent into a mixture of the alkali-rich metal material and the catalyst, continuing carrying out ball milling for 4-24 h, taking out mixed powder and drying.
In another embodiment of the present application, the catalyst may also be added in the form of a catalyst precursor. When the catalyst is added in the form of a precursor, the mixed raw material containing the alkali metal-rich material, the electron conductive agent, and the primary particles of the catalyst precursor may be compacted and granulated to form secondary particles. Wherein the catalyst precursor can form the catalyst in the mixing process of the raw materials.
Here, when the raw material of the positive electrode additive includes a raw material such as an ion conductive agent, the raw material may be added during the mixing process.
In addition, it is understood that the specific compaction and granulation processes are not limited in the examples of the present application, as long as the internal voids of the formed secondary particles are less than or equal to 500nm. By way of illustration, the compaction may be, for example, isostatic compaction or compression molding compaction, the pressure may be, for example, 0.1MPa to 500MPa, and the specific pressure value may be adjusted according to the raw material to ensure that the internal voids of the secondary particles after compaction are less than or equal to 500nm. In the granulation process, the compacted compact may be formed into secondary granules by crushing, sieving, etc. Wherein the particle diameter of the formed secondary particles is 1 to 50 μm.
In one embodiment of the present application, the method for preparing the positive electrode additive may further include: the secondary particles are coated to form a passivation layer on the surfaces of the secondary particles. The passivation layer can be formed by liquid phase coating, solid phase coating, gas phase coating and the like. The thickness of the formed passivation layer can be, for example, 10nm to 500nm, so as to improve the ion transmission performance of the positive electrode additive.
The positive electrode additive of the present application will be described in further detail below with reference to specific examples, which are taken as examples of lithium ion batteries.
Example 1
The embodiment provides a method for preparing a soft package lithium ion battery, wherein a positive electrode active material is Lithium Cobaltate (LCO), and a positive electrode additive comprises the following components: the preparation method comprises the following steps of taking modified lithium cobaltate as a catalytic inner core, taking lithium oxide as an alkali-rich metal material, taking Carbon Nanotubes (CNTs) as a conductive agent, and taking polyvinylidene fluoride (poly 1,1-difluoroethylene, PVDF) as a binder:
1) Preparation of Positive electrode additive
Raw material is Li 2 CoO 2 As a catalyst precursor, li 2 O is used as an alkali-rich metal material, CNTs is used as a conductive agent, the mass ratio of the three materials is 79 to 1, the ball material ratio is 20, firstly, a catalyst precursor is added, and after the ball milling is carried out for 48 hours at the rotating speed of 350r/min, lithium cobaltate is obtained, and an XRD test is carried out on the lithium cobaltate, so that the 006 crystal face diffraction peak is ensured to be stronger than other crystal face diffraction peaks; then Li is added 2 O, adjusting the rotating speed to 200r/min, ball-milling for 6 hours, adding CNTs dispersion liquid with 4% of solid content, continuously ball-milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting fine powder into an isostatic pressing device, setting the pressure to 300MPa, keeping the pressure for 5 minutes, then releasing pressure, taking out the sample, crushing, screening out particles with the particle size distribution within the range of 8-22 mu m, and placing the powder sample in CO for the next step 2 Heating to 100 deg.C in atmosphereAt a flow rate of 60sccm for 2 hours, the main objective of this step was to build dense Li on the particle surface 2 CO 3 Passivating the layer, and then collecting a sample to obtain the positive electrode additive. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Being a single crystal material of D50 μm, liCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 Manufacturing (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas can be generated in the formation stage, the generated gas can be discharged in the exhaust process, and electricity is supplied after an air bag is cut offThe cell is sealed. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 2
The embodiment provides a preparation method of a positive electrode additive, a button cell manufacturing and testing method, and a soft package full cell manufacturing method, and the preparation method specifically comprises the following steps:
1) Preparation of positive electrode additive
Raw material is Li 2 CoO 2 As a catalyst precursor, li 2 O is used as an alkali-rich metal material, CNTs is used as a conductive agent, the mass ratio of the three materials is 79 2 O, adjusting the rotating speed to 200r/min, ball-milling for 6 hours, adding CNTs dispersion liquid with 4% of solid content, continuously ball-milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting fine powder into an isostatic pressing device, setting the pressure to be 100MPa, keeping the pressure for 5 minutes, then releasing pressure, taking out the sample, crushing, screening out particles with the particle size distribution within the range of 8-22 mu m, and placing the powder sample in CO for the next step 2 Heating to 100 ℃ in an atmosphere, keeping the flow rate at 60sccm for 2 hours, wherein the main purpose of the step is to build compact Li on the particle surface 2 CO 3 Passivating the layer, and then collecting a sample to obtain the positive electrode additive. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Is a single crystal material with D50 of 14 mu mLiCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 Uniformly dispersing the materials and the positive electrode additive, adjusting the viscosity to be within 3000-8000, discharging after the fineness is less than 25 mu m, filtering, coating, drying, rolling and die-cutting to obtain the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 3
The embodiment provides a preparation method of a positive electrode additive and a button cell manufacturing and testing method, and a soft package full cell manufacturing and testing method, wherein the preparation method specifically comprises the following steps:
1) Preparation of Positive electrode additive
Raw material is Li 2 CoO 2 As a catalyst precursor, li 2 O is used as an alkali-rich metal material, CNTs is used as a conductive agent, the mass ratio of the three materials is 79 2 O, adjusting the rotating speed to 200r/min, ball-milling for 6 hours, and then addingContinuously ball-milling CNTs dispersion liquid with solid content of 4% for 4h, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting the fine powder into an isostatic pressing device, setting the pressure to be 400MPa, keeping for 5 min, then releasing the pressure, taking out the sample, crushing, screening out particles with the particle size distribution within the range of 8-22 mu m, and placing the powder sample in a CO device for the next step 2 Heating to 100 ℃ in an atmosphere, keeping the flow rate at 60sccm for 2 hours, wherein the main purpose of the step is to build compact Li on the particle surface 2 CO 3 Passivating the layer, and then collecting a sample to obtain the positive electrode additive. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8:1, dispersing the mixture in an NMP solution to prepare slurry, coating the slurry on the surface of an aluminum foil with the thickness of 9 mu m, drying, compacting by a roller press, cutting into an original sheet with the diameter of 13mm, selecting a lithium metal sheet as a negative electrode, matching a diaphragm electrolyte in a glove box to prepare a button cell, and testing the capacity of the button cell in a voltage interval of 3-4.5V at the multiplying power of 0.1C.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
LiCoO as raw material 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 Uniformly dispersing the materials and the positive electrode additive, adjusting the viscosity to be within 3000-8000, discharging after the fineness is less than 25 mu m, filtering, coating, drying, rolling and die-cutting to obtain the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 4
The embodiment provides a preparation method of a positive electrode additive, a button cell manufacturing and testing method, and a soft package full cell manufacturing method, and the preparation method specifically comprises the following steps:
1) Preparation of Positive electrode additive
The raw material is Li 2 CoO 2 As a catalyst precursor, li 2 O is used as an alkali-rich metal material, CNTs is used as a conductive agent, the mass ratio of the three materials is 79 2 O, adjusting the rotating speed to 200r/min, ball-milling for 6 hours, adding CNTs dispersion liquid with the solid content of 4%, continuing ball-milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting fine powder into a die pressing equipment steel die, keeping the pressure for 5 minutes, releasing the pressure, taking out the sample, crushing the sample, screening out particles with the particle size distribution within the range of 8-22 mu m, and placing the powder sample in CO for the next step 2 Heating to 100 ℃ in an atmosphere, keeping the flow rate at 60sccm for 2 hours, wherein the main purpose of the step is to build compact Li on the particle surface 2 CO 3 Passivating the layer, and then collecting a sample to obtain the positive electrode additive. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8:1, dispersing the mixture in an NMP solution to prepare slurry, coating the slurry on the surface of an aluminum foil with the thickness of 9 mu m, drying, compacting by a roller press, cutting into an original sheet with the diameter of 13mm, selecting a lithium metal sheet as a negative electrode, matching a diaphragm electrolyte in a glove box to prepare a button cell, and testing the capacity of the button cell in a voltage interval of 3-4.5V at the multiplying power of 0.1C.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 The particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 5
The embodiment provides a preparation method of a positive electrode additive, a button cell manufacturing and testing method, and a soft package full cell manufacturing method, and the preparation method specifically comprises the following steps:
1) Preparation of positive electrode additive
The raw material is Li 2 CoO 2 As a catalyst precursor, li 2 O is used as an alkali-rich metal material, CNTs is used as a conductive agent, the mass ratio of the three materials is 79 2 O, adjusting the rotating speed to 200r/min, ball-milling for 6 hours, adding CNTs dispersion liquid with the solid content of 4%, continuing ball-milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting fine powder into a die pressing equipment steel die, pressing to 550MPa, keeping for 5 minutes, releasing pressure, taking out the sample, crushing, screening out particles with the particle size distribution within the range of 8-22 mu m, and placing the powder sample in CO for the next step 2 Heating to 100 ℃ in an atmosphere at a flow rate of 60sccm for 2 hours, wherein the main purpose of the step is to build compact Li on the particle surface 2 CO 3 Passivating the layer, and then collecting a sample to obtain the positive electrode additive. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
LiCoO as raw material 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse evenly, and then adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to chemical conversion treatment, a large amount of gas is generated in the chemical conversion stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 6
This example provides a method for preparing a soft package secondary battery, in which a positive electrode active material is Lithium Cobaltate (LCO), and a positive electrode additive is composed of: modified NCM811 (LiNi) 0.8 Co 0.1 Mn 0.1 O 2 ) The catalyst is used as a catalytic core, lithium oxide is used as an alkali-rich metal material, carbon Nanotubes (CNTs) are used as a conductive agent, and polyvinylidene fluoride (poly 1,1-difluoroethylene, PVDF) is used as a binder, and the specific preparation method is as follows:
1) Preparation of Positive electrode additive
The raw material is selected from polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 O 2 As a catalyst precursor, li 2 CO 3 As an alkali-rich metal material, CNTs is used as a conductive agent, the mass ratio of the CNTs to the conductive agent is 79 2 CO 3 After ball milling for 6 hours at the rotating speed of 200r/min, adding CNTs dispersion liquid with the solid content of 4 percent, continuously ball milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting fine powder into isostatic pressing equipment, and setting the pressure300MPa, keeping for 5 minutes, then decompressing, taking out a sample, crushing, and screening out particles with the particle size distribution within the range of 8-22 mu m. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
LiCoO as raw material 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse evenly, and then adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the method adopted in the embodimentThe residue of the positive electrode additive of (2) is a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 7
The embodiment provides a preparation method of a positive electrode additive, a button cell manufacturing and testing method, and a soft package full cell manufacturing method, and the preparation method specifically comprises the following steps:
1) Preparation of positive electrode additive
The raw material is selected from polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 O 2 As a catalyst precursor, li 2 CO 3 As an alkali-rich metal material, CNTs is used as a conductive agent, the mass ratio of the CNTs to the CNTs is 69 2 CO 3 After the ball milling is carried out for 6 hours at the rotating speed of 200r/min, adding CNTs dispersion liquid with the solid content of 4 percent, continuously carrying out the ball milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting the fine powder into an isostatic pressing device, setting the pressure at 300MPa, maintaining for 5 minutes, then releasing the pressure, taking out the sample, crushing, and screening out particles with the particle size distribution within the range of 8-22 mu m. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse evenly, and then adding LiCoO 2 MaterialAnd a positive electrode additive, wherein the viscosity is adjusted to be within the range of 3000-8000 after the positive electrode additive is uniformly dispersed, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
The cathode was matched with a silica graphite cathode (hold capacity 500mAh/g, first effect 83%), and 1mol/L LiPF was used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 8
The embodiment provides a preparation method of a positive electrode additive, a button cell manufacturing and testing method, and a soft package full cell manufacturing method, and the preparation method specifically comprises the following steps:
1) Preparation of Positive electrode additive
The raw material is selected from polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 O 2 As a catalyst precursor, li 2 CO 3 As an alkali-rich metal material, CNTs is used as a conductive agent, the mass ratio of the CNTs to the CNTs is 59 2 CO 3 After ball milling is carried out for 6 hours at the rotating speed of 200r/min, CNTs dispersion liquid with the solid content of 4 percent is added, the ball milling is carried out for 4 hours, a sample is taken out and dried, the dried sample is crushed through a 300-mesh screen, fine powder is put into isostatic pressing equipment, the pressure is set to be 300MPa, the pressure is released after the sample is kept for 5 minutesTaking out the sample, crushing, and screening out the particles with the particle size distribution in the range of 8-22 mu m. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse evenly, and then adding LiCoO 2 Uniformly dispersing the materials and the positive electrode additive, adjusting the viscosity to be within 3000-8000, discharging after the fineness is less than 25 mu m, filtering, coating, drying, rolling and die-cutting to obtain the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this exampleIs a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 9
The embodiment provides a preparation method of a positive electrode additive and a manufacturing and testing method of a button cell, and a manufacturing method of a soft package full cell, which specifically comprises the following steps:
1) Preparation of Positive electrode additive
The raw material is selected from polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 O 2 As a catalyst precursor, li 2 CO 3 As an alkali-rich metal material, CNTs is used as a conductive agent, the mass ratio of the CNTs to the conductive agent is 49 2 CO 3 After the ball milling is carried out for 6 hours at the rotating speed of 200r/min, adding CNTs dispersion liquid with the solid content of 4 percent, continuously carrying out the ball milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting the fine powder into an isostatic pressing device, setting the pressure at 300MPa, maintaining for 5 minutes, then releasing the pressure, taking out the sample, crushing, and screening out particles with the particle size distribution within the range of 8-22 mu m. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of NCM811 cathode
Uniformly mixing a single crystal material and a polycrystalline material of a raw material NCM811 according to a mass ratio of 6:4, and mixing NCM811 particles, a positive electrode additive, PVDF particles and CNTs according to a ratio of 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 Material and anode additive, dispersing uniformly and then mixingThe pitch viscosity is within the range of 3000-8000, the fineness is less than 25 μm, then the material is discharged, and the pole piece is prepared by filtering, coating, drying, rolling and die cutting.
4) All-cell-preparation of the negative electrode
The cathode was matched with a silica graphite cathode (hold capacity 500mAh/g, first effect 83%), and 1mol/L LiPF was used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 10
The embodiment provides a preparation method of a positive electrode additive and a manufacturing and testing method of a button cell, and a manufacturing method of a soft package full cell, which specifically comprises the following steps:
1) Preparation of Positive electrode additive
The raw material is selected from polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 O 2 As a catalyst precursor, li 2 O is used as an alkali-rich metal material, CNTs and Lithium Lanthanum Zirconium Oxygen (LLZO) are used as conductive agents, the mass ratio of the CNTs to the Lithium Lanthanum Zirconium Oxygen (LLZO) is 0.5 2 Adjusting the rotation speed of O and LLZO to 200r/min, ball-milling for 6 hours, adding CNTs dispersion liquid with solid content of 4%, continuing ball-milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting the fine powder into an isostatic pressing device, setting the pressure to be 300MPa, keeping the pressure for 5 minutes, releasing pressure, taking out the sample, crushing the sample,the granules with the size distribution in the range of 8-22 μm are screened out. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8:1, dispersing the mixture in an NMP solution to prepare slurry, coating the slurry on the surface of an aluminum foil with the thickness of 9 mu m, drying, compacting by a roller press, cutting into an original sheet with the diameter of 13mm, selecting a lithium metal sheet as a negative electrode, matching a diaphragm electrolyte in a glove box to prepare a button cell, and testing the capacity of the button cell in a voltage interval of 3-4.5V at the multiplying power of 0.1C.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 Manufacturing (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 11
The embodiment provides a preparation method of a positive electrode additive, a button cell manufacturing and testing method, and a soft package full cell manufacturing method, and the preparation method specifically comprises the following steps:
1) Preparation of Positive electrode additive
The raw material is selected from polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 O 2 As a catalyst precursor, li 2 O is used as an alkali-rich metal material, CNTs and Lithium Aluminum Titanium Phosphate (LATP) are used as conductive agents, the mass ratio of the CNTs to the LATP is 79 2 Adjusting the rotation speed of O and LLZO to 200r/min, ball-milling for 6 hours, adding CNTs dispersion liquid with the solid content of 4%, continuing ball-milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting fine powder into an isostatic pressing device, setting the pressure to be 300MPa, maintaining for 5 minutes, releasing pressure, taking out the sample, crushing, and screening out particles with the particle size distribution within the range of 8-22 mu m. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Being a single crystal material of D50 μm, liCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 Material and anode additive, adjusting viscosity after dispersing uniformlyDischarging in the fineness of less than 25 μm within 3000-8000, filtering, coating, oven drying, rolling, and die cutting to obtain the final product.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to chemical conversion treatment, a large amount of gas is generated in the chemical conversion stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 12
The embodiment provides a preparation method of a positive electrode additive, a button cell manufacturing and testing method, and a soft package full cell manufacturing method, and the preparation method specifically comprises the following steps:
1) Preparation of Positive electrode additive
The raw material is selected from polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 O 2 As a catalyst precursor, lithium oxalate (Li) 2 C 2 O 4 ) As an alkali-rich metal material, graphene is used as a conductive agent, the mass ratio of the graphene to the conductive agent is 79 2 C 2 O 4 After ball milling for 6 hours at the rotating speed of 200r/min, adding graphene dispersion liquid with the solid content of 4%, continuously ball milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting fine powder into isostatic pressing equipment, setting the pressure to be 300MPa, maintaining for 5 minutes, and releasing pressureTaking out the sample, crushing, and screening out the particles with the particle size distribution in the range of 8-22 mu m. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this exampleIs a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 13
The embodiment provides a preparation method of a positive electrode additive and a manufacturing and testing method of a button cell, and a manufacturing method of a soft package full cell, which specifically comprises the following steps:
1) Preparation of Positive electrode additive
Ruthenium oxide is selected as a catalyst and Li is used as a raw material 2 CO 3 As an alkali-rich metal material, ketjen black is used as a conductive agent, the mass ratio of the Ketjen black to the conductive agent is 79 to 1, the ball-material ratio is 15, the three are added into a ball milling tank together, the rotating speed is adjusted to 350r/min, after ball milling is carried out for 40 hours, a sample is crushed and passes through a 300-mesh screen, fine powder is put into an isostatic pressing device, the pressure is set to 300MPa, pressure is released after the sample is kept for 5 minutes, the sample is taken out and crushed, and particles with the particle size distribution within the range of 8-22 μm are screened out. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse evenly, and then adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
Negative electrode with siliconGraphite oxide cathode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 14
The embodiment provides a preparation method of a positive electrode additive, a button cell manufacturing and testing method, and a soft package full cell manufacturing method, and the preparation method specifically comprises the following steps:
1) Preparation of Positive electrode additive
Cobalt oxide (Co) is selected as raw material 3 O 4 ) As catalyst, lithium sulfide (Li) 2 S) as an alkali metal-rich material, SP and CNTs as a conductive agent, wherein the mass ratio of the SP to the CNTs is 79 3 O 4 、Li 2 And S and SP are added into a ball milling tank together, the rotating speed is adjusted to 350r/min, after ball milling is carried out for 40 hours, CNTs dispersion liquid with the solid content of 4% is added, after ball milling is carried out for 4 hours, a sample is taken out and dried, the dried sample is crushed through a 300-mesh screen, fine powder is filled into an isostatic pressing device, the pressure is set to be 300MPa, pressure is relieved after the sample is kept for 5 minutes, the sample is taken out and crushed, and particles with the particle size distribution within the range of 8-22 mu m are screened out. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
LiCoO as raw material 2 Being a single crystal material of D50 μm, liCoO 2 The particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example is a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Example 15
The embodiment provides a preparation method of a positive electrode additive and a manufacturing and testing method of a button cell, and a manufacturing method of a soft package full cell, which specifically comprises the following steps:
1) Preparation of Positive electrode additive
The raw material is selected from iron carbide (Fe) 3 C) As catalyst, lithium peroxide (Li) 2 O 2 ) As an alkali-metal-rich material, graphene and CNTs are used as conductive agents, wherein the mass ratio of the four materials is 79 3 C and Li 2 O 2 Adding the materials into a ball milling tank together, adjusting the rotating speed to 350r/min, performing ball milling for 40 hours, adding CNTs dispersion liquid with the solid content of 4%, continuing ball milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, putting fine powder into isostatic pressing equipment, setting the pressure to be 300MPa, maintaining for 5 minutes, releasing pressure, taking out the sample, crushing, and screening out particles with the particle size distribution within the range of 8-22 mu m. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 The particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse evenly, and then adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
The cathode was matched with a silica graphite cathode (hold capacity 500mAh/g, first effect 83%), and 1mol/L LiPF was used 6 /(EC + DEC, 1:1) electrolyte, PP/PE/PP separator, making 2270mAhThe left and right soft package batteries are used for battery testing and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example is a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Comparative example 1
The present comparative example provides a method for preparing a soft package secondary battery, in which the positive active material is Lithium Cobaltate (LCO), and the composition of the positive additive is as follows: the preparation method comprises the following steps of taking modified lithium cobaltate as a catalytic core, taking lithium oxide as an alkali-rich metal material, and taking polyvinylidene fluoride (poly 1,1-difluoroethylene, PVDF) as a binder:
1) Preparation of Positive electrode additive
The raw material is Li 2 CoO 2 As a catalyst precursor, li 2 Taking O as an alkali-rich metal material, wherein the mass ratio of the O to the alkali-rich metal material is 80 2 Adjusting the rotation speed to 200r/min, ball-milling for 10 hours, taking out the sample, crushing, screening out particles with the particle size distribution of 8-22 mu m, and placing the powder sample in CO 2 Heating to 100 ℃ in the atmosphere, keeping the flow rate at 60sccm for 2 hours, and collecting a sample to obtain the positive electrode additive. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8:1, dispersing the mixture in an NMP solution to prepare slurry, coating the slurry on the surface of an aluminum foil with the thickness of 9 mu m, drying, compacting by a roller press, cutting into an original sheet with the diameter of 13mm, selecting a lithium metal sheet as a negative electrode, matching a diaphragm electrolyte in a glove box to prepare a button cell, and testing the capacity of the button cell in a voltage interval of 3-4.5V at the multiplying power of 0.1C.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Being a single crystal material of D50 μm, liCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 Uniformly dispersing the materials and the positive electrode additive, adjusting the viscosity to be within 3000-8000, discharging after the fineness is less than 25 mu m, filtering, coating, drying, rolling and die-cutting to obtain the pole piece.
4) All-cell-preparation of the negative electrode
The cathode was matched with a silica graphite cathode (hold capacity 500mAh/g, first effect 83%), and 1mol/L LiPF was used 6 (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example was a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Comparative example 2
The present comparative example provides a method for preparing a soft pack secondary battery, in which the positive active material is Lithium Cobaltate (LCO), and the positive additive is composed of: the preparation method comprises the following steps of taking modified lithium cobaltate as a catalytic inner core, taking lithium oxide as an alkali-rich metal material, taking Carbon Nanotubes (CNTs) as a conductive agent, and taking polyvinylidene fluoride (poly 1,1-difluoroethylene, PVDF) as a binder:
1) Preparation of positive electrode additive
The raw material is selected from polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 O 2 As a catalyst precursor, li 2 CO 3 As an alkali-rich metal material, CNTs is used as a conductive agent, the mass ratio of the CNTs to the conductive agent is 79 2 CO 3 After the ball milling is carried out for 6 hours at the rotating speed of 200r/min, adding CNTs dispersion liquid with the solid content of 4 percent, continuously carrying out the ball milling for 4 hours, taking out and drying the sample, crushing the dried sample through a 300-mesh screen, and collecting fine powder as an additive material. After the preparation, the performance of each parameter of the obtained positive electrode additive is tested, and the test results are listed in table 1.
2) And (3) making the buckle electric: uniformly mixing a positive electrode additive, SP and PVDF according to the proportion of 8.1.
3) All-cell-preparation of Li 2 CoO 2 Positive electrode
LiCoO as raw material 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 Particles, positive additive, PVDF particles, and CNTs were as follows 94:2:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse uniformly, and simultaneously adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
4) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 /(EC+DEC，1:1)Electrolyte and a PP/PE/PP diaphragm are manufactured into a soft package battery of about 2270mAh for battery testing and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The soft package battery is subjected to formation treatment, a large amount of gas is generated in the formation stage, the generated gas can be discharged in the exhaust process, and the battery is sealed after an air bag is cut off. Wherein, after formation, the residue of the positive electrode additive used in this example is a trace amount of LiCoO 2 Particles of the LiCoO 2 The particle size distribution of the particles is between 50nm and 20 μm.
Comparative example 3
The comparative example provides a preparation method of a soft package secondary battery, and the preparation method specifically comprises the following steps:
1) All-cell-preparation of Li 2 CoO 2 Positive electrode
Raw material LiCoO 2 Is a single crystal material with D50 of 14 μm, and LiCoO 2 Particles, PVDF particles and CNTs were measured according to 96:2:2, dissolving PVDF in N-Methylpyrrolidone (NMP) solvent to prepare gel, adding CNTs to disperse evenly, and then adding LiCoO 2 The material and the anode additive are dispersed uniformly, the viscosity is adjusted to be within the range of 3000-8000, the fineness is less than 25 mu m, and then the material is discharged, filtered, coated, dried, rolled and die-cut to prepare the pole piece.
2) All-cell-preparation of the negative electrode
The negative electrode matched with silica graphite negative electrode (fastening capacitance 500mAh/g, first effect 83%), 1mol/L LiPF is used 6 Manufacturing (EC + DEC, 1:1) electrolyte and a PP/PE/PP diaphragm into a soft package battery of about 2270mAh for battery test and use;
wherein: EC is ethylene carbonate;
DEC is diethyl carbonate, diethyl carbonate;
PP polypropylene, polypropylene;
PE polyethylene, polyethene.
The parameters of the specific positive electrode additives of examples 1 to 15 and comparative examples 1 to 3 are shown in table 1.
TABLE 1
Figure BDA0003291598190000211
In table 1, the maximum internal void width, area ratio, and particle size of the secondary particles were measured as follows.
Method for testing maximum internal void width of secondary particles: coating additive material powder with conductive resin to prepare slurry, cutting a sample by using an ion polishing interface technology (CP) after the slurry is solidified, observing the section of the sample under a Scanning Electron Microscope (SEM), finding secondary particles, and measuring and counting the size of gaps existing in the cross section of the particles.
The method for testing the area ratio comprises the following steps: the method comprises the steps of wrapping additive material powder with conductive resin to prepare slurry, cutting a sample by using an ion polishing interface technology (CP) after the slurry is solidified, observing the section of the sample under a Scanning Electron Microscope (SEM), finding secondary particles and taking an electron microscope picture of the particle section.
Method for testing particle size: the powder samples were dispersed in ethanol and tested using a laser particle sizer.
The specific capacity, the cycle performance and the volume expansion performance of the additive materials of examples 1 to 15 and comparative examples 1 to 3 were measured, respectively, and the results are shown in table 2.
The specific capacity testing method comprises the following steps: mixing an additive material, carbon black and a PVDF binder according to the proportion of 8.
Off potential of additive material:
uniformly mixing an additive material, SP and PVDF according to the proportion of 8.
The cycle performance test method comprises the following steps:
and (3) carrying out a 1C charging/1C discharging cyclic charging and discharging test on the manufactured soft package battery on a testing machine, recording the first discharging capacity as C1, stopping the test if the discharging capacity is lower than 80 percent C1 in the circulating process, and determining the number of the circulating circles between C1 and 80 percent C1 as the circulating life of the battery cell.
Volume expansion test method:
the manufactured soft package battery is adjusted to 50% SOC state, then 5 points are counted in total at four corners and the center position of the battery cell, the point is taken, the thickness of the battery cell is measured, the average value is taken as the initial thickness of the battery cell, and the initial thickness is recorded as D1. After the cell has cycled to 500 cycles, the pouch cell is adjusted to 100% SOC, and the cell thickness is also measured at 5 points in total at the four corners and center of the cell and averaged to give the 500 cycle thickness of the cell and recorded as D2, and (D2-D1)/D1 is recorded as the cell thickness growth rate.
TABLE 2
Figure BDA0003291598190000221
As can be seen from the data of examples 1 to 5 and comparative examples 1 to 2 in table 2, as the internal voids of the secondary particles increase, the charge capacity of the positive electrode additive gradually decreases, the cycle life of the resulting battery cell decreases, and when the internal voids exceed 500nm, the cycle life of the battery cell significantly decreases. It can be seen from the data in examples 6-8 that the charge capacity of the resulting positive electrode additive and the cycle life of the resulting cell also fluctuate significantly when the area ratio of the alkali metal-rich material to the catalyst is varied. Example 9 is a lithium ion battery with a positive electrode active material of NCM811, and compared to a conventional cell without a positive electrode additive, the cycle life of the cell is significantly improved, where the cycle life of the conventional NCM811 cell without a positive electrode additive is generally about 800 cycles.
In addition, from the comparative data of examples 10 to 15, it is clear that the types of the alkali-rich material, the electron conductive agent and the catalyst also have a certain influence on the charge capacity of the obtained positive electrode additive and the cycle life of the obtained cell. Examples 1-15 show an increase in both the charge capacity of the additive material and the cycle life of the cell as compared to comparative example 3. In addition, as can be seen from the test data in table 2, compared with comparative examples 1-2, the lithium removal sites of the button half cells corresponding to examples 1-5 are relatively low, and the charging capacities of the additive materials corresponding to examples 1-5 are also high, so that the purpose of improving the comprehensive performance of the secondary battery can be achieved.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (23)

1. A positive electrode additive for a secondary battery, comprising secondary particles including at least two kinds of primary particles, at least one of the primary particles being an alkali metal-rich material and at least one of the primary particles being an electron conductive agent; in the molecular formula of the alkali metal-rich material, the molecular weight of alkali metal elements accounts for more than 10% of the total molecular weight of the alkali metal-rich material; wherein the gap between adjacent primary particles is less than or equal to 500nm.
2. The positive electrode additive according to claim 1, wherein the voids between adjacent primary particles are less than or equal to 300nm.
3. The positive electrode additive as claimed in claim 1 or 2, wherein the alkali metal-rich material is present in an area ratio of 50% to 90% in at least one cross-sectional range of 5 μm x 5 μm in the secondary particles.
4. The positive electrode additive according to any one of claims 1 to 3, wherein the alkali metal-rich material is present in the positive electrode additive in an amount of 10 to 70% by mass.
5. The positive electrode additive as claimed in any one of claims 1 to 4, wherein the alkali metal-rich material comprises at least one of an alkali metal oxide, an alkali metal superoxide, an alkali metal peroxide, or an inorganic alkali metal salt; wherein the content of the first and second substances,
the inorganic alkali metal salt includes alkali metal carbonate and/or alkali metal oxalate.
6. The positive electrode additive according to any one of claims 1 to 5, wherein the electron conductive agent is contained in the positive electrode additive in an amount of 0.1 to 5% by mass.
7. The positive electrode additive as claimed in any one of claims 1 to 6, wherein the secondary particles further comprise a catalyst, and the catalyst has an area ratio of 5% to 95% in at least a cross-sectional range of 5 μm x 5 μm.
8. The positive electrode additive according to claim 7, wherein the mass ratio of the catalyst in the positive electrode additive is 30% to 90%.
9. The positive electrode additive according to claim 7 or 8, wherein the particle size of the catalyst is 50nm to 500nm.
10. The positive electrode additive as recited in any one of claims 7 to 9, wherein the catalyst comprises at least one of elemental transition metal, transition metal carbide, transition metal oxide, transition metal sulfide, or transition metal lithium oxide.
11. The positive electrode additive as claimed in any one of claims 7 to 10, wherein the catalyst has a density greater than that of the alkali metal rich material, and the alkali metal rich material has a density greater than that of the electron conductive agent.
12. The positive electrode additive according to any one of claims 7 to 11, wherein the electron conductive agent is a linear structure and/or a planar structure;
the distance D1 between the two farthest points of the linear structure is greater than the sum of the particle diameter D2 of the alkali metal-rich material and the particle diameter D3 of the catalyst;
the distance D1 between the two farthest points of the planar structure is larger than the sum of the particle diameter D2 of the alkali metal-rich material and the particle diameter D3 of the catalyst.
13. The positive electrode additive as claimed in claim 12, wherein D1, D2 and D3 satisfy: 1 is formed by the woven fabrics D1/(D2 + D3) and is less than or equal to 50.
14. The positive electrode additive according to claim 12 or 13, wherein D2 and D3 satisfy: d2<1/2D3.
15. The positive electrode additive as claimed in any one of claims 1 to 14, wherein the electron conductive agent comprises at least one of carbon nanotubes, carbon nanofibers, graphite or graphene.
16. The positive electrode additive as claimed in any one of claims 1 to 15, wherein the surface of the secondary particles is coated with a passivation layer.
17. A method for preparing a positive electrode additive according to any one of claims 1 to 16, comprising:
and compacting and granulating the primary particles of the raw materials to form the secondary particles, wherein gaps inside the formed secondary particles are less than or equal to 500nm.
18. The method for preparing the composite material according to claim 17, wherein the compacting and granulating the primary particles of the raw material comprises:
compacting and granulating a mixed raw material of primary particles containing an alkali metal-rich material, an electron conductive agent and a catalyst to form secondary particles;
or, compacting and granulating a mixed raw material containing the alkali metal-rich material, the electron conductive agent and the primary particles of the catalyst precursor to form the secondary particles.
19. The method of claim 18, wherein the primary particles of the alkali-metal-rich material and the primary particles of the catalyst are both nanoparticles.
20. Use of a positive electrode additive as defined in any one of claims 1 to 16 in the manufacture of a secondary battery.
21. A secondary battery is characterized by comprising a positive electrode, a negative electrode, a diaphragm arranged between the positive electrode and the negative electrode and an electrolyte, wherein the electrolyte infiltrates the diaphragm; the positive electrode comprises a positive electrode current collector and a positive electrode material layer, wherein the positive electrode material layer is mainly prepared from a positive electrode active material and the positive electrode additive as defined in any one of claims 1 to 16.
22. The secondary battery according to claim 21, wherein the positive electrode additive is present in the positive electrode material layer in a proportion of 0.1 to 10% by mass in the preparation of the positive electrode material layer.
23. A terminal device characterized by comprising an electric element and the secondary battery according to claim 21 or 22, wherein the secondary battery is electrically connected to the electric element to supply electric power to the electric element.
CN202111165759.1A 2021-09-30 2021-09-30 Positive electrode additive, preparation method and application thereof, secondary battery and terminal equipment Pending CN115881960A (en)

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