WO2023160307A1 - 正极补锂添加剂及其制备方法和应用 - Google Patents

正极补锂添加剂及其制备方法和应用 Download PDF

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WO2023160307A1
WO2023160307A1 PCT/CN2023/072605 CN2023072605W WO2023160307A1 WO 2023160307 A1 WO2023160307 A1 WO 2023160307A1 CN 2023072605 W CN2023072605 W CN 2023072605W WO 2023160307 A1 WO2023160307 A1 WO 2023160307A1
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lithium
positive electrode
additive
lithium supplement
electrode lithium
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PCT/CN2023/072605
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English (en)
French (fr)
Inventor
朱成奔
万远鑫
孔令涌
钟泽钦
钟文
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深圳市德方创域新能源科技有限公司
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Publication of WO2023160307A1 publication Critical patent/WO2023160307A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H01M4/1315—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx containing halogen atoms, e.g. LiCoOxFy
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the application belongs to the field of secondary batteries, and specifically relates to a positive electrode lithium supplement additive and its preparation method and application.
  • Lithium-ion batteries are considered to be the most promising due to their high working voltage and energy density, relatively small self-discharge level, no memory effect, no pollution from heavy metal elements such as lead and cadmium, and long cycle life. one of the energy sources. Lithium-ion batteries are widely used in many aspects such as electric vehicles, power tools, mobile consumer electronics, and energy storage.
  • the most commonly used cathode materials for lithium-ion batteries are mainly lithium iron phosphate, lithium nickel cobalt manganese (aluminum) acid ternary materials (commonly known as ternary materials), lithium cobalt oxide, lithium manganese oxide, etc., and carbon-based graphite is the most widely used negative electrode. materials and silicon-based anode materials.
  • lithium-ion batteries have many advantages , during the first charging process of lithium-ion batteries , the surface of the negative electrode is usually accompanied by the formation of a solid electrolyte film SEI film. Irreversibly consumed, the reversible specific capacity of the corresponding cell decreases.
  • Anode materials will further consume Li + , resulting in loss of lithium in cathode materials, reducing the first Coulombic efficiency and battery capacity of the battery. For example, in a lithium-ion battery system using a graphite negative electrode, about 10% of the lithium source will be consumed for the first charge.
  • anode materials with high specific capacity such as alloys (silicon, tin, etc.), oxides (silicon oxide, tin oxide), and amorphous carbon anodes, the consumption of lithium sources in the cathode will be further aggravated.
  • lithium-rich compounds have a good effect of supplementing lithium
  • Sensitive, gel is prone to occur during homogenization, resulting in processing failure, and even reacts with water to deteriorate. Therefore, the processing process has extremely strict requirements on water control, and it is difficult to implement large-scale application on existing battery production lines. Due to the high alkali, the electrochemical performance of the lithium-rich compound such as the lithium supplementation effect needs to be improved.
  • the lithium-rich metal salt lithium supplement material and the electrolyte are likely to react at the interface to generate dangerous gases, which poses certain safety hazards.
  • the electrical conductivity of these materials is not good, resulting in poor electrical performance of the material, and the lithium supplementation effect cannot be well exerted.
  • the purpose of this application is to overcome the above-mentioned deficiencies in the prior art, and provide a positive electrode lithium supplement additive and its preparation method to solve the problems of existing positive electrode lithium supplement additives, such as poor storage and processability and potential safety hazards caused by easy gas production. question.
  • Another object of the present application is to provide a positive electrode sheet and a secondary battery containing the electrode sheet, so as to solve the technical problems of unsatisfactory electrochemical performance such as the first coulombic efficiency of the existing secondary battery.
  • the first aspect of the present application provides a positive electrode lithium supplement additive.
  • the positive electrode lithium-replenishing additive of the present application includes a lithium-replenishing material, and the lithium-replenishing material also contains fluorine atoms, and the fluorine atoms replace the oxygen atoms in the lithium-replenishing material and are in oxygen vacancies.
  • the fluorine atoms replacing the oxygen atoms are 0.01-0.8 times the number of moles of oxygen atoms in the positive electrode lithium supplement additive.
  • the fluorine atoms replacing the oxygen atoms are 0.01-0.1 times the number of moles of oxygen atoms in the positive electrode lithium supplement additive.
  • the surface layer or surface of the positive electrode lithium supplement additive also contains hydrophobic fluoride.
  • the hydrophobic fluoride includes lithium fluoride.
  • the mass content of the hydrophobic fluoride in the positive electrode lithium supplement additive is 0.1%-2%.
  • the particle size of the lithium-supplementing additive for the positive electrode is 1-20 ⁇ m.
  • the lithium-supplementing material includes L x M y O z , wherein, L in the molecular formula is Li or/and a mixed alkali metal element of Li and not more than 30% of at least one of K and Na; M includes Fe, Co , Ni, Mn, V, Fe-Co, Cu, Mo, Al, Ti, Mg; 0 ⁇ x ⁇ 6, 0 ⁇ y ⁇ 3, 0 ⁇ z ⁇ 5.
  • L x My O z includes at least one of Li 5 Fe 0.98 Al 0.02 O 4 , Li 2 NiO 2 , Li 5 FeO 4 , Li 2 MnO 2 , Li 6 MnO 4 , and Li 2 CuO 2 .
  • the positive electrode lithium-replenishing additive also includes a hydrophobic encapsulation layer, and the hydrophobic encapsulation layer covers the lithium-replenishing material.
  • the hydrophobic encapsulation layer includes at least one of an ion conductor encapsulation layer and an electronic conductor encapsulation layer.
  • the material of the ion conductor encapsulation layer includes at least one of perovskite type, NASICON type and garnet type.
  • the material of the electronic conductor packaging layer includes at least one of carbon materials, conductive oxides, and conductive organics.
  • the thickness of the hydrophobic encapsulation layer is 5-100 nm.
  • the second aspect of the present application provides a preparation method of the positive electrode lithium supplement additive of the present application.
  • the preparation method of the positive electrode lithium supplement additive of the present application comprises the following steps:
  • the precursor mixture material is sintered in an inert atmosphere to obtain a positive electrode lithium supplement additive.
  • the lithium-supplementing material precursor includes the above-mentioned L x My O z precursor; wherein, L in the molecular formula is Li or/and a mixed alkali metal element of Li and not more than 30% of at least one of K and Na; M includes at least one of Fe, Co, Ni, Mn, V, Fe-Co, Cu, Mo, Al, Ti, Mg; 0 ⁇ x ⁇ 6, 0 ⁇ y ⁇ 3, 0 ⁇ z ⁇ 5.
  • the lithium-supplementing material precursor includes a transition metal salt and oxygen element, and the molar ratio of the fluorine element in the fluorine source to the oxygen element in the transition metal salt is 0.01-1:1.
  • the temperature of the sintering treatment is 500-1000° C., and the time is 4-24 hours.
  • the fluorine source includes ammonium fluoride, sodium fluoride, potassium fluoride, lithium fluoride, aluminum fluoride, hydrofluoride At least one of potassium and sodium bifluoride.
  • the sintering treatment also includes forming a hydrophobic encapsulation layer covering the material on the surface of the material after the sintering treatment.
  • an electrode sheet in a third aspect of the present application, includes a current collector and an electrode active layer bonded to the surface of the current collector.
  • the electrode active layer contains the positive lithium supplementary additive of the present application or the positive lithium supplementary additive prepared by the preparation method of the positive lithium supplementary additive of the present application.
  • a secondary battery in a fourth aspect of the present application, includes a positive electrode sheet and a negative electrode sheet, and the positive electrode sheet and/or the negative electrode sheet are the electrode sheets of this application.
  • the positive electrode lithium supplement additive of this application is doped with fluorine, and replaces oxygen vacancies, and the residual alkali content is reduced, which endows the positive electrode lithium supplement additive of this application with higher rate performance, and has better high pressure and good thermal stability at the same time, which improves lithium supplement
  • the lithium supplement effect of the material has high electrochemical performance and safety.
  • due to the doping of fluorine and the reduction of residual alkali content it can also significantly improve the positive electrode lithium supplement additive of the application against the negative effects of adverse factors such as water and carbon dioxide in the environment, and effectively improve the storage stability and storage stability of the positive electrode lithium supplement additive of the application. Processing performance, thereby improving the cycle and electrochemical performance of the corresponding electrode, reducing gas production, and high safety.
  • the hydrophobic encapsulation layer and fluorine doping together play a synergistic effect, improving the storage stability and processing of the positive electrode lithium supplement additive of the present application properties and corresponding electrochemical properties.
  • the preparation method of the positive electrode lithium-replenishing additive of the present application can effectively dope fluorine atoms in the lithium-replenishing material and replace the oxygen atoms contained in the lithium-replenishing material, thereby endowing the prepared positive electrode lithium-replenishing additive with better storage stability, processing performance and Thermal stability, high rate performance and high voltage characteristics improve the lithium supplementation effect and electrochemical performance of lithium supplementation materials, as well as high safety.
  • the preparation method of the positive electrode lithium supplement additive can ensure that the prepared positive electrode lithium supplement additive is stable in structure and electrochemical performance, has high efficiency, and saves production costs.
  • the positive electrode lithium supplement additive contained in the electrode sheet of this application can be used as a "sacrifice agent" during the first cycle of charging to supplement the negative electrode to form SEI
  • the irreversible lithium ions are consumed by the membrane, so as to maintain the abundance of lithium ions in the battery system and improve the overall electrochemical performance of the battery such as first efficiency, high voltage resistance and thermal stability.
  • the lithium ion battery of the present application has excellent first-time Coulombic efficiency, battery capacity, cycle performance and safety, long life and stable electrochemical performance.
  • the term "and/or” describes the association relationship of associated objects, indicating that there may be three relationships, for example, A and/or B may mean: A exists alone, A and B exist simultaneously, and B exists alone Condition. Among them, A and B can be singular or plural.
  • the character "/" generally indicates that the contextual objects are an "or" relationship.
  • At least one means one or more, and “multiple” means two or more.
  • At least one of the following” or similar expressions refer to any combination of these items, including any combination of single or plural items.
  • at least one item (unit) of a, b, or c or “at least one item (unit) of a, b, and c” can mean: a, b, c, a-b( That is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.
  • sequence numbers of the above-mentioned processes do not mean the order of execution, and some or all steps may be executed in parallel or sequentially, and the execution order of each process shall be based on its functions and The internal logic is determined and should not constitute any limitation to the implementation process of the embodiment of the present application.
  • the weight of the relevant components mentioned in the description of the embodiments of the present application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the various components.
  • the scaling up or down of the content of the fraction is within the scope disclosed in the description of the embodiments of the present application.
  • the mass described in the description of the embodiments of the present application may be ⁇ g, mg, g, kg and other well-known mass units in the chemical industry.
  • the embodiment of the present application provides a positive electrode lithium supplement additive.
  • the positive electrode lithium-replenishing additive in the embodiment of the present application includes a lithium-replenishing material and a fluorine atom doped with the lithium-replenishing material, and the fluorine atom replaces the oxygen atom in the lithium-replenishing material and is in an oxygen vacancy.
  • the lithium-replenishing material contained in the positive electrode lithium-replenishing additive of the embodiment of the present application is rich in lithium, thereby ensuring that the positive electrode lithium-replenishing additive of the embodiment of the present application can provide abundant lithium.
  • the positive electrode lithium supplement additive of the embodiment of the present application contains doped fluorine, and replaces the oxygen atom and is in an oxygen vacancy, thereby endowing the positive electrode lithium supplement additive of the embodiment of the present application with higher rate performance, and at the same time has higher high pressure and thermal stability.
  • the lithium supplementing effect of the lithium supplementing material is improved, its electrochemical performance and safety are high, and the residual alkali content is low, which effectively improves the positive electrode lithium supplementing additive of the embodiment of the present application against the negative impact of adverse factors such as water and carbon dioxide in the environment,
  • the positive electrode lithium-supplementing additive is endowed with high storage stability and processing performance, and can also reduce gas production, thereby improving the cycle, electrochemical performance and safety performance of the corresponding battery.
  • the content of the fluorine atom replacing the oxygen atom in the positive electrode lithium supplement additive in the embodiment of the present application is that the fluorine atom replacing the oxygen atom is 0.01-0.8 times the molar number of oxygen atoms in the positive electrode lithium supplement additive, and further 0.01 -0.1 times, that is, the molar ratio of the fluorine atom replacing the oxygen atom to the oxygen atom is 0.01-0.8:1, further 0.01-0.1:1.
  • the above-mentioned performance of the positive electrode lithium supplement additive in the embodiment of the present application can be improved, such as reducing the residual alkali content of the positive electrode lithium supplement additive, improving the storage stability, processing performance and rate performance of the positive electrode lithium supplement additive, At the same time, it has high voltage and thermal stability, improves the lithium supplementing effect of the lithium supplementing material, and has high electrochemical performance and safety.
  • the surface layer or surface of the positive electrode lithium supplement additive in the embodiment of the present application also contains Has hydrophobic fluoride.
  • the hydrophobic fluoride may be combined on the surface of the positive electrode lithium-replenishing additive of the embodiment of the present application, such as forming a coating layer, or doped and distributed in the surface layer of the positive electrode lithium-replenishing additive of the embodiment of the present application. In this way, the hydrophobic fluoride can play a synergistic effect with doped fluorine atoms, effectively improve the lithium ion conductivity of the positive electrode lithium supplement additive, and improve the lithium supplement effect of the positive electrode lithium supplement additive.
  • the hydrophobic fluoride can also play a role in isolating the environment with the fluorine atom, such as insulating unfavorable factors such as water vapor in the environment and the lithium supplement material, and protecting the lithium supplement material, thereby improving the positive lithium supplement additive of the embodiment of the present application. Lithium supplementation stability, storage performance and processing performance.
  • the content of the hydrophobic fluoride in the positive electrode lithium supplement additive is 0.1-2%.
  • the content of the hydrophobic fluoride in the positive electrode lithium supplement additive can be 0.1% or 0.2%. , 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2% and other typical but non-limiting contents.
  • the lithium-supplementing material in each of the above embodiments may include L x My O z .
  • L in the molecular formula of L x My O z is Li or/and a mixed alkali metal element of Li and at least one of K and Na not exceeding 30%;
  • M includes Fe, Co, Ni, Mn, V, Fe - at least one of Co, Cu, Mo, Al, Ti, Mg; 0 ⁇ x ⁇ 6, 0 ⁇ y ⁇ 3, 0 ⁇ z ⁇ 5. Therefore, according to the type of elements mentioned in M, the lithium supplement material can be at least one of iron-based lithium supplement materials, manganese-based lithium supplement materials, nickel-based lithium supplement materials, and the like.
  • M in L x My O z is Fe and Al.
  • the lithium-rich lithium supplementary material represented by L x My O z may be Li 5 Fe 0.98 Al 0.02 O 4 . It is also possible, but not limited to, Li 2 NiO 2 , Li 5 FeO 4 , Li 2 MnO 2 , Li 6 MnO 4 , Li 2 CuO 2 and the like. These lithium-supplementing materials are rich in lithium, and can release lithium ions during the first cycle of charging to effectively supplement lithium.
  • the lithium-replenishing material When the lithium-replenishing material has an inverse fluorite structure, it can also improve the unidirectional capacity characteristics of the lithium-replenishing material, thereby ensuring the lithium-replenishing effect of the positive electrode lithium-replenishing additive of the present application.
  • the lithium-supplementing material is doped with aluminum elements, Al atoms exist in the form of replacing iron atoms in the lattice. Al atoms in this form can widen the transmission channel of lithium ions and increase the extraction rate of lithium ions.
  • the type of positive electrode lithium-replenishing material such as positive electrode lithium-replenishing material or negative electrode lithium-replenishing material
  • the type of positive electrode lithium-replenishing additive in the embodiment of the present application is determined, such as positive electrode lithium-replenishing additive.
  • the morphology and particle size of the positive electrode lithium-supplementing additives in the above-mentioned embodiments can be adjusted according to actual production conditions or application needs.
  • the morphology can be but limited to the particle shape, and the particle size can be but limited to 1-20 ⁇ m. 2-20 ⁇ m.
  • the overall particle size of the positive electrode lithium supplement additive in the embodiment of the present application can be controlled and adjusted, so as to fully exert the lithium supplement effect of the lithium supplement material.
  • the positive electrode lithium supplement additive in the embodiment of the present application further includes a hydrophobic encapsulation layer.
  • the hydrophobic encapsulation layer covers the core body formed by the lithium-supplementing material above.
  • the hydrophobic encapsulation layer covers the outer surface of the lithium fluoride coating layer.
  • the hydrophobic encapsulation layer can effectively cover the above lithium supplement material, and the above lithium supplement material can be coated by the hydrophobic encapsulation layer, thereby improving the above lithium supplement material and
  • the external isolation effect prevents the external environment such as moisture and carbon dioxide from contacting the above lithium-replenishing material, ensures the stability of the above-mentioned lithium-replenishing material, and thus ensures the lithium-replenishing effect and stability of the positive electrode lithium-replenishing additive of this application.
  • the hydrophobic encapsulation layer can be a layer structure that can effectively isolate unfavorable factors such as water vapor or carbon dioxide in the environment, then its material can be able to form a dense hydrophobic coating Layer and effectively ensure the stability of granular lithium supplement materials.
  • the material of the hydrophobic encapsulation layer can also be an ionic conductor encapsulation layer that can be beneficial to ion conduction, or an electronic conductor encapsulation layer that is conducive to improving conductivity, and certainly can be an ion conductor encapsulation layer and an electronic conductor encapsulation layer. composite layer structure.
  • any layer of the ionic conductor encapsulation layer or the electronic conductor encapsulation layer can be directly coated on the above granular supplementary material with lithium fluoride on its surface. surface of the lithium material.
  • the ionic conductor encapsulation layer can improve the intercalation and extraction effect of lithium ions on lithium ions and the ionic conductivity of lithium ions.
  • the electronic conductor encapsulation layer can improve the electronic conductivity of the lithium supplement material, improve its conductivity and conductivity, stimulate the gram capacity of the positive electrode lithium supplement additive, and realize the real high-efficiency lithium supplement.
  • the ion conductor encapsulation layer plays a role in improving lithium ion conductivity. Therefore, the material of the ion conductor encapsulation layer can be a material that is conducive to the improvement of ion conductivity, For example, at least one of perovskite type, NASICON type and garnet type may be included but not limited.
  • the perovskite type includes Li 3x La 2/3-x TiO 3 (LLTO), specifically Li 0.5 La 0.5 TiO 3 , Li 0.33 La 0.57 TiO 3 , Li 0.29 La 0.57 TiO 3 , Li 0.33 Ba At least one of 0.25 La 0.39 TiO 3 , (Li 0.33 La 0.56 ) 1.005 Ti 0.99 Al 0.01 O 3 , Li 0.5 La 0.5 Ti 0.95 Zr 0.05 O 3 , etc., NASICON type such as but not only Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 (LATP), garnet type including Li 7 La 3 Zr 2 O 12 (LLZO), Li 6 ⁇ 4 La 3 Zr 1 ⁇ 4 Ta 0 ⁇ 6 O 12 , Li 6.5 La 3 Zr 1.5 Ta 0.5 At least one of O 12 .
  • LLTO Li 3x La 2/3-x TiO 3
  • the ion conductivity of the ion conductor encapsulation layer can be further improved.
  • the electronic conductor encapsulation layer can enhance the electronic conductivity of the hydrophobic encapsulation layer, thereby enhancing the electronic conductivity of the positive electrode lithium supplement additive, which is conducive to reducing the internal impedance of the electrode.
  • the electronic conductor packaging layer can also be used for secondary use, and it plays an auxiliary role as a conductive agent inside the electrode.
  • the electronic conductor encapsulation layer or the ionic conductor encapsulation layer can further enhance the compactness of the hydrophobic encapsulation layer, thereby improving the lithium supplementation stability and lithium supplementation effect of the positive electrode lithium supplementation additive.
  • the electronic conductor packaging layer can be fully covered or partially covered.
  • the material of the electronic conductor encapsulation layer includes at least one of carbon materials, conductive oxides, and conductive organics.
  • the carbon material includes at least one of amorphous carbon, carbon nanotubes, graphite, carbon black, graphene, and the like.
  • the conductive oxide when the electronic conductor encapsulation layer is made of conductive oxide, the conductive oxide may include at least one of In 2 O 3 , ZnO, and SnO 2 .
  • the conductive organic substance may be a conductive polymer or the like.
  • the thickness of the hydrophobic encapsulation layer may be 5-100 nm.
  • it can be adjusted by controlling the thickness of the ionic conductor encapsulation layer and the electronic conductor encapsulation layer included in the above hydrophobic encapsulation layer. Controlling the thickness of the hydrophobic encapsulation layer within this range can improve the compactness of the hydrophobic encapsulation layer, further improve the storage stability and processing stability of the positive electrode lithium supplement additive, and simultaneously improve the ion and/or electronic conductivity of the positive electrode lithium supplement additive.
  • hydrophobic encapsulation layer can also include other functional layers as required, and the types of other functional layers can be You can choose flexibly according to your needs.
  • the lithium-replenishing material forming the nucleus can be at least one of primary particles and secondary particles of the lithium-replenishing material.
  • the embodiment of the present application also provides a preparation method of the above positive electrode lithium supplement additive.
  • the preparation method of the positive electrode lithium supplement additive in the embodiment of the present application comprises the following steps:
  • the lithium-replenishing material precursor in step S01 is a precursor for forming the lithium-replenishing material contained in the positive electrode lithium-replenishing additive of the above-mentioned application example, as in the embodiment, the lithium-replenishing material precursor may include L x M y O z precursor. Then, after the sintering treatment in the step S02, the precursor of the lithium-supplementing material generates L x M y O z as above.
  • the fluorine source in step S01 is to provide fluorine atoms, therefore, in the embodiment, the fluorine source includes ammonium fluoride, sodium fluoride, potassium fluoride, lithium fluoride, aluminum fluoride, potassium bifluoride, sodium bifluoride at least one. These fluorine sources can replace the oxygen atoms contained in the lithium-supplementing material generated during the sintering process by fluorine atoms during the sintering process in step S02.
  • the mixing ratio of the fluorine source and the precursor of the lithium-replenishing material should satisfy that in the generated positive electrode lithium-replenishing additive, the fluorine atom replacing the oxygen atom is 0.01-0.1 times the molar number of oxygen atoms in the positive electrode lithium-replenishing additive.
  • the lithium supplementary material precursor when the lithium supplementary material precursor includes a mixture of transition metal salts, lithium sources and other raw materials, then at this time the lithium supplementary material precursor contains oxygen elements, such as the lithium supplementary material precursor is L x M y O z precursor, then at this time the molar ratio of the fluorine element in the fluorine source to the oxygen element in the transition metal salt is 0.01-1:1, further 0.01-0.1:1, and further 0.02-0.2:1 .
  • the amount of fluorine atoms replacing oxygen atoms can be moderately controlled, thereby improving the rate performance, voltage and thermal stability of the positive electrode lithium supplement additive, and at the same time adjusting and controlling the particle size of the positive electrode lithium supplement additive. diameter, making its particle size relatively small.
  • the mixture formed by raw materials including transition metal salt, lithium source and the like is in the lithium supplement material precursor, and the transition metal salt can be the transition metal shown in M in L x M y O z , such as but not only Only ferric ammonium oxalate, ferric nitrate (manganese, copper), ferric sulfate (manganese, copper), ferric chloride (manganese, copper), ferric oxide (manganese dioxide, manganese oxide, cupric oxide, cuprous oxide ), one or more of iron acetate, the lithium source can but not only include at least one of LiOH, Li 2 CO 3 , CH 3 COOLi, CH 3 CH 2 OLi, LiNO 3 , LiCl, Li 2 SO 4 .
  • the mixing process in step S01 may be a solid-phase mixing process or a liquid-phase mixing method.
  • the solid-phase mixing treatment may include at least one of solid-phase ball mill mixing, soybean milk machine mixing, three-dimensional mixer mixing, high-efficiency mixer mixing, fusion machine mixing, and the like.
  • the liquid phase mixing method may include stirring mixing, liquid phase mixing followed by spray drying, sol-gel method, and the like.
  • a dispersant can also be added, and the dispersant is one or more of polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), polyvinyl alcohol, and the amount of the dispersant added can be transitional Metal salts and iron sources account for 1-5% of the total mass, and the air inlet temperature of the spray drying is 110-180°C.
  • PVP polyvinylpyrrolidone
  • PEG polyethylene glycol
  • the amount of the dispersant added can be transitional Metal salts and iron sources account for 1-5% of the total mass, and the air inlet temperature of the spray drying is 110-180°C.
  • step S02 during the sintering process of the precursor mixture, the precursor of the lithium-replenishing material in the precursor mixture reacts to form a lithium-replenishing material, such as the above-mentioned lithium-replenishing material.
  • the fluorine source also participates in the reaction. Since the diameter difference between the fluorine atom and the oxygen atom is small, and because the diameter difference between the fluorine atom and the oxygen atom is small, under the action of high temperature, partial substitution is easy to occur, that is, fluorine Substitute oxygen atoms, so that fluorine atoms replace part of the oxygen atoms in the lithium-supplementing material and occupy the oxygen vacancies of the oxygen atoms.
  • the temperature of the sintering treatment is 500-1000° C., and the time is 4-24 hours.
  • the sintering treatment conditions such as an inert atmosphere and the temperature range, can effectively make the precursor of the lithium-replenishing material react to form the lithium-replenishing material.
  • the generated positive electrode lithium supplement additive is a material with good stability, and its reactivity is not high. Therefore, it is difficult for the fluorine source to react directly with the positive electrode lithium supplement additive to form fluoride, but to make the fluorine Atoms replace the oxygen atoms in the lithium-supplementing material without destroying the structure of the lithium-supplementing material itself.
  • the residual alkali or lithium metal on the surface of the positive lithium supplement additive is a highly reactive substance, so it can react with the fluorine source more easily to form fluoride. In this way, the voltage and thermal stability of the lithium-replenishing material can be improved, and the electrochemical performance and safety performance of the positive electrode lithium-replenishing additive generated by the sintering process can be improved.
  • the fluorine source will also interact with the generated complementary materials during the sintering process.
  • These precursor raw materials or other residual alkalis and other impurities on the surface or surface of lithium materials react to generate hydrophobic fluorides, such as lithium fluoride, etc., so as to improve the ion conductivity of the positive electrode lithium supplement additive and isolate the environment, etc. effect.
  • the inert atmosphere ensures the stability of the target product generated by the sintering process.
  • it can be an atmosphere composed of a chemically inert gas.
  • the chemically inert gas can be a conventional chemically inert gas, such as Ar, N 2. At least one of He and the like.
  • a step of forming a hydrophobic encapsulation layer on the surface of the lithium-supplementing material is also included.
  • the method of forming the hydrophobic encapsulation layer can be formed by selecting a corresponding or suitable method according to the structure and material of the film layer.
  • the carbon coating layer may be coated by pyrolysis using a solid carbon source. If a solid carbon source is used for coating, firstly, the crushed material of the positive electrode lithium supplement additive after the cracking treatment is mixed with the solid carbon source.
  • the mixing method includes ball mill solid phase mixing, soybean milk machine mixing, and three-dimensional mixer mixing , high-efficiency mixer mixing, fusion machine mixing, etc. at least one of them.
  • sintering is carried out under inert conditions.
  • the carbon source may be at least one of glucose, sucrose, starch, citric acid, cellulose, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), pitch and the like.
  • the inert atmosphere can be at least one of Ar, N 2 and He.
  • the sintering temperature can be 400-800°C, and the time is 1-10h. This sintering treatment can make the carbon coating layer uniform and dense.
  • the mass ratio of the final carbon to the lithium-supplementing material can be controlled as (2-20):100. If the final carbon content is too low, the carbon cannot completely cover the lithium-supplementing material, and there will be defect positions in the surface conductivity of the material. ; If the carbon content is too high, the capacity of carbon itself is low, which will reduce the overall capacity of the material.
  • the above-mentioned preparation method of the positive electrode lithium-replenishing additive performs in-situ doping on the lithium-replenishing material through a fluorine source, which can effectively dope the lithium-replenishing material with fluorine atoms and replace the oxygen atoms contained in the lithium-replenishing material, thereby endowing the prepared positive electrode with
  • the lithium supplement additive has high rate performance, voltage and thermal stability, improves the lithium supplement effect and electrochemical performance of the lithium supplement material, and has high safety.
  • the preparation method of the positive electrode lithium supplement additive can ensure that the prepared positive electrode lithium supplement additive is stable in structure and electrochemical performance, and has high efficiency and saves production cost.
  • the embodiment of the present application further provides an electrode sheet.
  • the electrode sheet of the embodiment of the present application includes an electrode collector and an electrode active layer bonded to the surface of the electrode collector.
  • the electrode active layer contains the positive electrode lithium supplement additive of the above embodiment of the application.
  • the positive electrode lithium-replenishing additive contained in the electrode sheet plays the above role and can be used as a lithium source for the first cycle of charging
  • a "sacrifice agent” it is first consumed to supplement the irreversible lithium ions consumed by the formation of the SEI film on the negative electrode, so as to maintain the abundance of lithium ions in the battery system and improve the first efficiency and overall electrochemical performance of the battery.
  • the quality of the electrode sheet is stable and the yield rate is high.
  • the mass content of the electrode positive electrode lithium-supplementing additive contained in the above-mentioned application embodiment in the electrode active layer may be 1-20wt%; preferably, 2-10wt%.
  • the electrode active layer includes in addition to the electrode positive electrode lithium supplement additive, also includes electrode active materials, binders and conductive agents, wherein the binder can be commonly used electrode binders, such as polyvinylidene chloride, soluble polyvinyl chloride Tetrafluoroethylene, styrene-butadiene rubber, hydroxypropyl methylcellulose, methylcellulose, carboxymethylcellulose, polyvinyl alcohol, acrylonitrile copolymer, sodium alginate, chitosan and chitosan derivatives one or more of .
  • the binder can be commonly used electrode binders, such as polyvinylidene chloride, soluble polyvinyl chloride Tetrafluoroethylene, styrene-butadiene rubber, hydroxypropyl methylcellulose, methyl
  • the conductive agent may be a commonly used conductive agent, such as one or more of graphite, carbon black, acetylene black, graphene, carbon fiber, C60 and carbon nanotubes.
  • the electrode active material can be a positive electrode active material or a negative electrode active material.
  • the positive electrode active material includes lithium cobaltate, lithium manganate, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadyl phosphate, fluorinated One or more of lithium vanadium phosphate, lithium titanate, lithium nickel cobalt manganate, and lithium nickel cobalt aluminate.
  • the preparation process of the electrode sheet can be as follows: the electrode active material, the electrode positive electrode lithium supplement additive, the conductive agent and the binder are mixed to obtain the electrode slurry, and the electrode slurry is coated on the electrode current collector, dried, rolled
  • the electrode sheet is prepared by pressing, die-cutting and other steps.
  • the embodiment of the present application further provides a secondary battery.
  • the secondary battery of the embodiment of the present application includes necessary components such as a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte, and of course other necessary or auxiliary components.
  • the positive electrode sheet or/and the negative electrode sheet are the electrode sheets of the above-mentioned embodiments of the present application, specifically, when The above-mentioned electrode sheet is a positive electrode sheet, and contains the positive electrode lithium-replenishing additive of the above text application embodiment, and the positive electrode lithium-replenishing additive is a positive electrode lithium-replenishing additive, then the positive electrode sheet contained in the secondary battery is the above-mentioned embodiment of the application electrode sheet (positive electrode piece).
  • the secondary battery of the embodiment of the present application contains the positive electrode lithium supplement additive of the above text application example, based on the above text application example, the positive electrode lithium supplement additive has excellent lithium supplement performance or further has ion conductivity and/or electron conductivity, processing Performance, giving the secondary battery of the embodiment of the present application excellent first-time Coulombic efficiency, battery capacity and cycle performance, long life, and stable electrochemical performance.
  • This embodiment provides a fluorine-doped cathode lithium supplement additive and a preparation method thereof.
  • the positive electrode lithium-replenishing additive includes Li2NiO2 lithium-replenishing material and a carbon coating layer covering the lithium-replenishing material.
  • the lithium supplement material is doped with fluorine atoms.
  • Li 2 NiO 2 lithium-supplementing material precursor and ammonium fluoride are mixed in the solid state according to the molar ratio of 1:0.2 (the molar ratio of oxygen to fluorine is 1:0.1) to obtain the precursor mixture material;
  • the precursor mixture material was sintered at 580° C. for 12 hours in an argon-protected environment to obtain a fluorine-doped lithium-supplementing material
  • the lithium supplement material in this example is doped with fluorine atoms, which replace the oxygen atoms in the lithium supplement material, and the formed compound is Li 2 NiO 1.96 F 0.08 .
  • the positive electrode lithium supplement is measured by a laser particle size analyzer.
  • the particle diameter D50 of the additive was 5.32 ⁇ m.
  • the positive electrode lithium supplement additive includes Li 5 FeO 4 lithium supplement material and a carbon coating layer covering the lithium supplement material.
  • the lithium supplement material is doped with fluorine atoms.
  • Li 5 FeO 4 lithium-supplementing material precursor and sodium bifluoride are mixed in the solid state according to the molar ratio of 1:0.3 (the molar ratio of oxygen to fluorine is 1:0.15) to obtain the precursor mixture material;
  • the precursor mixture material was sintered at 650° C. for 8 hours in an argon-protected environment to obtain a fluorine-doped lithium-replenishing material
  • the lithium supplement material in this example is doped with fluorine atoms, which replace the oxygen atoms in the lithium supplement material, and the formed compound is Li 5 FeO 3.93 F 0.14 .
  • the positive electrode lithium supplement is measured by a laser particle size analyzer.
  • the particle diameter D50 of the additive was 3.64 ⁇ m.
  • This comparative example provides a positive electrode lithium supplement additive and a preparation method thereof.
  • the positive electrode lithium-replenishing additive is the lithium-replenishing material prepared in step S1 in Example 1, which is the core body and the carbon coating layer prepared in step S3 in Example 1. That is to say, compared with Example 1, the positive electrode lithium-supplementing additive of this comparative example does not contain doped fluorine atoms.
  • This comparative example provides a positive electrode lithium supplement additive and a preparation method thereof.
  • the positive electrode lithium-replenishing additive is the lithium-replenishing material prepared in step S1 in Example 2 as a nucleus and the carbon coating layer prepared in step S3 in Example 2. That is to say, compared with Example 1, the positive electrode lithium-supplementing additive of this comparative example does not contain doped fluorine atoms.
  • the positive electrode supplementary lithium additive provided by the above-mentioned embodiment 1 to embodiment 2 and the positive electrode supplementary additive provided by the comparative example Lithium additives are assembled into positive electrodes and lithium-ion batteries according to the following methods:
  • the mass ratio of the four is 95:2:3, and the main material is nano-lithium iron phosphate material.
  • the lithium supplement material is 3% of the mass of the main material, and the material is mixed evenly with N-methylpyrrolidone (NMP) as a solvent to make a slurry, and then evenly coated on the surface of the aluminum foil, rolled to a certain thickness, and vacuumed at 110°C Dry for 12 hours to make a positive electrode sheet; wherein, the positive lithium supplement additives are the positive lithium supplement additives provided in the above-mentioned Examples 1 to 2 and the positive lithium supplement additives provided in the comparative example;
  • NMP N-methylpyrrolidone
  • Diaphragm polypropylene microporous membrane
  • Battery casing (including negative electrode casing, stainless steel gasket and positive electrode casing) model is CR2032;
  • Lithium-ion battery assembly the assembly sequence of negative electrode case-stainless steel gasket-lithium metal sheet-diaphragm-electrolyte-positive electrode sheet-positive electrode case is assembled into a half-cell in an inert atmosphere glove box.
  • Test conditions put the assembled battery on the shelf in a constant temperature room at 25°C, and conduct a charge and discharge test after leaving it aside for 6 hours. First charge to 4.3V with a constant current of 0.05C, then charge with a constant voltage until the cut-off current is 0.01C, then discharge at 0.05C to 2V, start the second round of charge and discharge, adjust the voltage window to 2-3.75V, and charge at 0.05C Discharge, the constant voltage charge cut-off current is 0.01C, cycle to 100 circles under this charge and discharge condition. Record the first charge and discharge capacity of the battery, and the charge and discharge capacity of the 100th lap.
  • the first Coulombic efficiency is the ratio of the first discharge capacity to the first charge capacity
  • the 100-cycle capacity retention rate is the ratio of the 100th cycle discharge capacity to the first discharge capacity
  • the lithium-replenishing material when the lithium-replenishing material is doped with fluorine and coated with carbon, it is specifically like the positive electrode lithium-replenishing additive in Example 1 and Example 2. Due to surface reaction and carbon deposition, under the premise of both containing carbon coating layer, the particle size of the positive electrode lithium supplement additive containing fluorine-doped nuclei is slightly larger than that of the non-fluorine-doped nuclei. For example, the material particle size D50 of Example 1 is larger than that of Comparative Example 1, and the material particle size D50 of Example 2 is larger than that of Comparative Example 2.
  • the first charge capacity and the discharge capacity of the embodiment 1 and the embodiment 2 are obviously improved compared with the comparative example 1 and the comparative example 2, and the first effect is relatively the comparative example 1 and the comparative example.
  • Ratio 2 has also been significantly improved. This is because the structure of the lithium-supplementing material is more stable after fluorine doping and carbon coating, and the influence of moisture in the processing environment becomes weaker, that is, the material deteriorates less, so it can play a better role. High charge capacity.
  • the lithium-supplementing material hardly intercalates lithium after delithiation for the first time, that is, it no longer participates in the electrochemical reaction in the battery, the structure of the fluorine-doped material is stable after delithiation, and due to the carbon-coated The material has good electrical conductivity, so it can also serve as a conductive agent in the battery after delithiation.
  • the positive electrode lithium-supplementing additive of the embodiment of the present application is ideal to design the positive electrode lithium-supplementing additive of the embodiment of the present application as a core-shell structure, and use the lithium-replenishing material in which fluorine atoms replace oxygen vacancies as the core body, so as to improve the high pressure and thermal stability of the positive electrode lithium-supplementing additive of the embodiment of the present application Performance and lithium supplementation effect and other characteristics, thereby improving the cycle performance and safety performance of the corresponding battery.

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Abstract

申请公开了一种正极补锂添加剂及其制备方法和应用。本申请正极补锂添加剂包括补锂材料，在补锂材料中还含有氟原子，且氟原子替代补锂材料中的氧原子并处于氧空位。本申请正极补锂添加剂采用氟掺杂，具有较好的高压和热稳定性能以及较高倍率性能，降低残碱含量，具有高的存储稳定性和良好的加工性能，而且还能够降低产气量，从而提高相应电池的循环和电化学性能以及安全性能。另外，正极补锂添加剂的制备方法能够保证制备的正极补锂添加剂结构和电化学性能稳定，而且效率高，节约生产成本。

Description

正极补锂添加剂及其制备方法和应用
本申请要求于2022年02月25日提交中国专利局，申请号为202210184488.2，申请名称为“正极补锂添加剂及其制备方法和应用”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请属于二次电池领域，具体涉及一种正极补锂添加剂及其制备方法和应用。
背景技术
20世纪60、70年代的石油能源危机问题迫使人们去寻找新的可替代的新能源，随着人们对环境保护和能源危机意识的增强。锂离子电池因其具备较高的工作电压与能量密度、相对较小的自放电水平、无记忆效应、无铅镉等重金属元素污染、超长的循环寿命等优点，被认为是最具应用前景的能源之一。锂离子电池被广泛应用于电动车、电动工具、可移动电子消费品以及储能等诸多方面。
目前最常用的锂离子电池正极材料主要有磷酸铁锂、镍钴锰(铝)酸锂三元材料(俗称三元材料)、钴酸锂、锰酸锂等，负极应用最多的是碳基石墨材料以及硅基负极材料等。虽然锂离子电池有很多优点，但是锂离子电池在首次充电过程中，负极表面通常伴随着固态电解质膜SEI膜的形成，这个过程会消耗大量的Li+，意味着从正极材料脱出的Li+部分被不可逆消耗，对应电芯的可逆比容量降低。负极材料特别是硅基负极材料则会进一步消耗Li+，造成正极材料的锂损失，降低电池的首次库伦效率和电池容量。如在使用石墨负极的锂离子电池体系中，首次充电会消耗约10％的锂源。当采用高比容量的负极材料，例如合金类(硅、锡等)、氧化物类(氧化硅、氧化锡)和无定形碳负极时，正极锂源的消耗将进一步加剧。
为改善由于负极不可逆损耗引起的低库伦效率问题，研究者开发出了相关富锂化合物，作为补锂添加剂来解决首次充放电锂离子不可逆损耗的问题。
虽然该些富锂化合物具有良好的补锂作用，但是也存在一些不足，如现有材料制备工艺及原料性质问题，经常会导致原料反应不完全(也即残碱较高)，导致材料对水敏感，匀浆时容易发生凝胶导致加工失败，甚至与水反应发生变质。因此，加工过程对水控制要求极其严格，难以在现有电池产线上进行大规模应用。由于碱较高也会导致富锂化合物的补锂效果等电化学性能有待提高。同时，由于高电压情况下，富锂金属盐类补锂材料与电解液容易在界面发生反应生成危险性气体，存在一定的安全隐患。而且，这些材料自身的导电性并不好，导致材料电性能发挥较差，无法较好发挥补锂作用。
技术问题
本申请的目的在于克服现有技术的上述不足，提供一种正极补锂添加剂及其制备方法，以解决现有正极补锂添加剂存在储存性和加工性不佳和易产气导致安全隐患等技术问题。
本申请的另一目的在于提供一种正极片和含有该电极片的二次电池，以解决现有二次电池首次库伦效率等电化学性能不理想的技术问题。
技术解决方案
为了实现上述申请目的，本申请的第一方面，提供了一种正极补锂添加剂。本申请正极补锂添加剂包括补锂材料，在补锂材料中还含有氟原子，且氟原子替代补锂材料中的氧原子并处于氧空位。
进一步地，替代所述氧原子的所述氟原子是所述正极补锂添加剂中的氧原子摩尔数的0.01-0.8倍。
进一步地，替代所述氧原子的所述氟原子是所述正极补锂添加剂中的氧原子摩尔数的0.01-0.1倍。
进一步地，正极补锂添加剂的表层中或表面还含有疏水氟化物。
具体地，疏水氟化物包括氟化锂。
更进一步地，疏水氟化物在正极补锂添加剂的质量含量为0.1％-2％。
进一步地，正极补锂添加剂的粒径为1-20μm。
进一步地，补锂材料包括LxMyOz，其中，分子式中的L为Li或/和Li与不超过30％的K、Na中至少一种的混合碱金属元素；M包括Fe、Co、Ni、Mn、V、Fe-Co、Cu、Mo、Al、Ti、Mg其中的至少一种；0＜x≤6，0＜y≤3，0＜z≤5。
具体地，LxMyOz包括Li5Fe0.98Al0.02O4、Li2NiO2、Li5FeO4、Li2MnO2、Li6MnO4、Li2CuO2中的至少一种。
进一步地，正极补锂添加剂还包括疏水封装层，疏水封装层包覆补锂材料。
更进一步地，疏水封装层包括离子导体封装层、电子导体封装层中的至少一层。
具体地，离子导体封装层的材料包括钙钛矿型、NASICON型、石榴石型中的至少一种。
具体地，电子导体封装层的材料包括碳材料、导电氧化物、导电有机物中的至少一种。
进一步地，疏水封装层的厚度为5-100nm。
本申请的第二方面，提供了本申请正极补锂添加剂的制备方法。本申请正极补锂添加剂的制备方法包括如下步骤：
将补锂材料前驱体与氟源进行混合处理，得到前驱体混合物料；
将前驱体混合物料于惰性气氛中烧结处理，得到正极补锂添加剂。
进一步地，补锂材料前驱体包括上述LxMyOz前驱体；其中，分子式中的L为Li或/和Li与不超过30％的K、Na中至少一种的混合碱金属元素；M包括Fe、Co、Ni、Mn、V、Fe-Co、Cu、Mo、Al、Ti、Mg其中的至少一种；0＜x≤6，0＜y≤3，0＜z≤5。
进一步地，补锂材料前驱体包括过渡金属盐和氧元素，且氟源中的氟元素与过渡金属盐中氧元素的摩尔比为0.01-1:1。
进一步地，烧结处理的温度为500-1000℃，时间为4-24h。
进一步地，氟源包括氟化铵、氟化钠、氟化钾、氟化锂、氟化铝、氟氢化 钾、氟氢化钠中的至少一种。
进一步地，在烧结处理后，还包括在经烧结处理后的材料表面形成包覆材料的疏水封装层。
本申请的第三方面，提供了一种电极片。本申请电极片包括集流体和结合在集流体表面的电极活性层，电极活性层中含有本申请正极补锂添加剂或由本申请正极补锂添加剂制备方法制备的正极补锂添加剂。
本申请的第四方面，提供了一种二次电池。本申请包括正极片和负极片，正极片和/或负极片为本申请电极片。
与现有技术相比，本申请具有以下的技术效果：
本申请正极补锂添加剂采用氟掺杂，并取代氧空位，残碱含量降低，赋予本申请正极补锂添加剂较高的倍率性能，同时具有较好的高压和良好热稳定性能，提高了补锂材料的补锂效果，其电化学性能和安全性高。同时，由于氟的掺杂和残碱含量的降低，还能够显著提高本申请正极补锂添加剂抗环境中如水、二氧化碳等不利因素的负面影响，有效提高本申请正极补锂添加剂的存储稳定性和加工性能，从而提高相应电极的循环和电化学性能，降低产气量，安全性高。进一步地，当本申请正极补锂添加剂含有疏水氟化物和/或疏水封装层时，该疏水封装层与氟掺杂一起起到增效作用，提高本申请正极补锂添加剂的存储稳定性和加工性能以及相应的电化学性能。
本申请正极补锂添加剂的制备方法能够有效在补锂材料中掺杂氟原子，并取代补锂材料所含氧原子，从而赋予制备的正极补锂添加剂具有较好的存储稳定性、加工性能和热稳定性能以及较高的倍率性能和高压特性，提高了补锂材料的补锂效果和电化学性能以及安全性高。另外，正极补锂添加剂的制备方法能够保证制备的正极补锂添加剂结构和电化学性能稳定，而且效率高，节约生产成本。
本申请电极片由于含有本申请正极补锂添加剂，因此，本申请电极片所含的正极补锂添加剂能够在首圈充电过程中作为“牺牲剂”，用以补充负极形成SEI 膜而消耗掉的不可逆的锂离子，从而保持电池体系内锂离子的充裕，提高电池首效和耐高电压以及热稳定性等整体电化学性能。
本申请二次电池由于含有本申请电极片，因此，本申请锂离子电池具有优异的首次库伦效率、电池容量和循环性能以及安全性，寿命长，电化学性能稳定。
本发明的实施方式
为了使本申请要解决的技术问题、技术方案及有益效果更加清楚明白，以下结合实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本申请，并不用于限定本申请。
本申请中，术语“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B的情况。其中A，B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。
本申请中，“至少一个”是指一个或者多个，“多个”是指两个或两个以上。“以下至少一项(个)”或其类似表达，是指的这些项中的任意组合，包括单项(个)或复数项(个)的任意组合。例如，“a,b,或c中的至少一项(个)”，或，“a,b,和c中的至少一项(个)”，均可以表示：a,b,c,a-b(即a和b),a-c,b-c,或a-b-c，其中a,b,c分别可以是单个，也可以是多个。
应理解，在本申请的各种实施例中，上述各过程的序号的大小并不意味着执行顺序的先后，部分或全部步骤可以并行执行或先后执行，各过程的执行顺序应以其功能和内在逻辑确定，而不应对本申请实施例的实施过程构成任何限定。
在本申请实施例中使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本申请。在本申请实施例和所附权利要求书中所使用的单数形式的“一种”、“所述”和“该”也旨在包括多数形式，除非上下文清楚地表示其他含义。
本申请实施例说明书中所提到的相关成分的重量不仅仅可以指代各组分的具体含量，也可以表示各组分间重量的比例关系，因此，只要是按照本申请实施例说明书相关组分的含量按比例放大或缩小均在本申请实施例说明书公开的范围之内。具体地，本申请实施例说明书中所述的质量可以是μg、mg、g、kg等化工领域公知的质量单位。
第一方面，本申请实施例提供了一种正极补锂添加剂。本申请实施例正极补锂添加剂包括补锂材料和掺杂补锂材料的氟原子，且氟原子替代补锂材料中的氧原子并处于氧空位。这样，本申请实施例正极补锂添加剂所含的补锂材料为富含锂，从而保证本申请实施例正极补锂添加剂能够提供丰富的锂，其作为正极补锂添加剂加入电极中后，使得在首圈充电过程中作为“牺牲剂”，尽可能一次性将该正极补锂添加剂所含的全部锂离子释放出来，用以补充负极形成SEI膜而消耗掉的不可逆的锂离子。本申请实施例正极补锂添加剂含掺杂氟，且取代氧原子并处于氧空位，从而赋予本申请实施例正极补锂添加剂较高的倍率性能，同时具有较高的高压和热稳定等性能，提高了补锂材料的补锂效果，其电化学性能和安全性高，而且残碱含量低，有效提高了本申请实施例正极补锂添加剂抗环境中包括水、二氧化碳等不利因素的负面影响，赋予该正极补锂添加剂具有高的存储稳定性和加工性能，而且还能够降低产气量，从而提高相应电池的循环和电化学性能以及安全性能。
实施例中，替代氧原子的氟原子在本申请实施例正极补锂添加剂中含量为替代氧原子的该氟原子是该正极补锂添加剂中的氧原子摩尔数的0.01-0.8倍，进一步为0.01-0.1倍，也即是替代氧原子的氟原子与该氧原子摩尔比为0.01-0.8：1，进一步为0.01-0.1：1。通过对氟掺杂量的控制，能够提高本申请实施例正极补锂添加剂的上述性能，如降低正极补锂添加剂的残碱含量，提高正极补锂添加剂的储存稳定性和加工性能以及倍率性能，同时具有高的电压和热稳定性能，提高了补锂材料的补锂效果，其电化学性能和安全性高。
在进一步实施例中，在本申请实施例正极补锂添加剂的表层中或表面还含 有疏水氟化物。具体的该疏水氟化物可以是结合在本申请实施例正极补锂添加剂的表面，如可以形成包覆层，还可以是掺杂分布在本申请实施例正极补锂添加剂的表层中。这样，该疏水氟化物能够与掺杂氟原子起到增效作用，有效改善正极补锂添加剂的锂离子导率，提高正极补锂添加剂的补锂效果。同时疏水氟化物还能够与氟原子起到隔绝环境作用，如起到隔绝环境中如水汽等不利因素与补锂材料，起到保护补锂材料的作用，从而提高本申请实施例正极补锂添加剂的补锂稳定性和储存性能以及加工性能。
在上述疏水氟化物的实施例基础上，该疏水氟化物在正极补锂添加剂的含量为0.1-2％，示范例中，该疏水氟化物在正极补锂添加剂的含量可以为0.1％、0.2％、0.5％、0.8％、1％、1.2％、1.5％、1.8％、2％等典型但非限制性的含量。通过对疏水氟化物含量控制，能够提高疏水氟化物在上述的作用，从而提高本申请实施例正极补锂添加剂补锂效果、补锂稳定性和储存性能以及加工性能。
实施例中，上述各实施例中的补锂材料可以包括LxMyOz。其中，LxMyOz分子式中的L为Li或/和Li与不超过30％的K、Na中至少一种的混合碱金属元素；M包括Fe、Co、Ni、Mn、V、Fe-Co、Cu、Mo、Al、Ti、Mg其中的至少一种；0＜x≤6，0＜y≤3，0＜z≤5。因此，根据M所述元素种类，补锂材料可以是铁系补锂材料、锰系补锂材料、镍系锂材料等中的至少一种。在具体实施例中，LxMyOz中M为Fe和Al。此时，LxMyOz所示的富锂补锂材料可以是Li5Fe0.98Al0.02O4。还可以但不仅仅为Li2NiO2、Li5FeO4、Li2MnO2、Li6MnO4、Li2CuO2等。该些补锂材料富含锂，能够在首圈充电过程中释放锂离子起到有效的补锂作用。当该补锂材料为反萤石结构时，还能够提高补锂材料单向容量特性，从而保证本申请正极补锂添加剂补锂效果。当补锂材料含有铝元素掺杂时，Al原子以替代铁原子晶格的形式存在，这种形式存在的Al原子可以拓宽锂离子的传输通道，并能够提高锂离子的脱出速率。
另外，根据补锂材料的种类如为正极补锂材料或负极补锂材料，决定了本申请实施例正极补锂添加剂的种类，如为正极补锂添加剂。
其次，上述各实施例正极补锂添加剂的形貌和粒径大小可以根据实际的生产条件或应用的需要进行调整，如形貌可以但限于颗粒形貌，粒径可以但限于1-20μm，进一步为2-20μm。通过对正极补锂添加剂的形貌和粒径等进行控制和调节，可以实现对本申请实施例正极补锂添加剂整体粒径进行控制和调节，从而充分发挥补锂材料的补锂效果。
在上述各实施例的基础上，作为本申请实施例中，本申请实施例正极补锂添加剂还包括疏水封装层。疏水封装层包覆上文补锂材料形成的核体。如当结合在补锂材料表面的疏水氟化锂形成包覆层时，该疏水封装层包覆在氟化锂包覆层外表面。通过对本申请实施例正极补锂添加剂增设该疏水封装层，该疏水封装层能够有效包覆上文补锂材料，通过该疏水封装层包覆上文补锂材料，从而提高上文补锂材料与外界隔离效果，避免外界中如水分和二氧化碳与上文补锂材料的接触，保证上文补锂材料的稳定性从而保证本申请正极补锂添加剂的补锂效果和补锂的稳定性。
当本申请实施例正极补锂添加剂含有上述疏水封装层时，该疏水封装层可以是能够有效隔绝环境中的如水汽或二氧化碳等不利因素的层结构，那么其材料可以是能够形成致密疏水包覆层而有效保证颗粒状补锂材料稳定性的材料。在此基础上，该疏水封装层的材料还可以是能够利于离子传导的离子导体封装层，也可以是利于提高导电性的电子导体封装层，当然也可以是离子导体封装层与电子导体封装层的复合层结构。当疏水封装层为离子导体封装层与电子导体封装层的复合层结构时，该离子导体封装层或电子导体封装层任一层可以直接包覆在表面结合有氟化锂的上文颗粒状补锂材料的表面。其中，离子导体封装层能够改善补锂材料对锂离子的嵌脱效果和锂离子的离子导率。电子导体封装层能够改善补锂材料的电子导率，提高其导导电性能，激发正极补锂添加剂的克容量发挥，实现真正意义上的高效补锂。
当疏水封装层包括离子导体封装层时，该离子导体封装层起到提高锂离子导率作用。因此，该离子导体封装层的材料可以是有利于离子导率提高的材料， 如可以但不仅仅包括钙钛矿型、NASICON型、石榴石型中的至少一种。具体实施例中，钙钛矿型包括Li3xLa2/3-xTiO3(LLTO)，具体如Li0.5La0.5TiO3、Li0.33La0.57TiO3、Li0.29La0.57TiO3、Li0.33Ba0.25La0.39TiO3、(Li0.33La0.56)1.005Ti0.99Al0.01O3、Li0.5La0.5Ti0.95Zr0.05O3等中的至少一种，NASICON型如但不仅仅为Li1.4Al0.4Ti1.6(PO4)3(LATP)，石榴石型包括Li7La3Zr2O12(LLZO)、Li6·4La3Zr1·4Ta0·6O12，Li6.5La3Zr1.5Ta0.5O12中的至少一种。通过对离子导体封装层材料选择，能够进一步提高离子导体封装层离子电导率。
当疏水封装层包括电子导体封装层时，该电子导体封装层能够增强疏水封装层的电子电导率，从而增强正极补锂添加剂的电子电导率，有利于减小电极内部的阻抗。同时，在上述颗粒状补锂材料作为“牺牲品”释放过程中和释放完毕之后，电子导体封装层还可以进行二次利用，在电极内部起到导电剂的辅助作用。而且该电子导体封装层或进一步与离子导体封装层起到致密性的增效作用，提高疏水封装层的致密性，从而提高正极补锂添加剂的补锂稳定性和补锂效果。基于电子导体封装层的作用，可以是电子导体封装层全包覆，也可以是部分包覆。实施例中，电子导体封装层的材料包括碳材料、导电氧化物、导电有机物中的至少一种。具体实施例中，电子导体封装层的材料为碳材料时，碳材料包括无定形碳、碳纳米管、石墨、炭黑、石墨烯等中的至少一种。另些具体实施例中，电子导体封装层的材料为导电氧化物时，导电氧化物可以包括In2O3、ZnO、SnO2中的至少一种。导电有机物可以是导电聚合物等。通过调节电子导体封装层的含量和材料，能够进一步提高其电子电导率。
进一步实施例中，疏水封装层的厚度可以为5-100nm。如可以通过控制上文疏水封装层所含的离子导体封装层、电子导体封装层的厚度进行调节。将疏水封装层厚度的控制在该范围，能够提高疏水封装层的致密性，进一步提高正极补锂添加剂的存储稳定性和加工稳定性，同时提高正极补锂添加剂的离子和/或电子导率。
另外，疏水封装层还可以根据需要包括其他功能层，其他功能层的种类可 以根据需要进行灵活选择。
实施例中，当本申请实施例正极补锂添加剂含有疏水封装层时，形成核体的补锂材料可以是补锂材料的一次颗粒、二次颗粒中的至少一种。
第二方面，本申请实施例还提供了上文正极补锂添加剂的制备方法。本申请实施例正极补锂添加剂的制备方法包括以下步骤：
S01：将补锂材料前驱体与氟源进行混合处理，得到前驱体混合物料；
S02：将前驱体混合物料于惰性气氛中烧结处理，得到正极补锂添加剂。
其中，步骤S01中的补锂材料前驱体为形成上文本申请实施例正极补锂添加剂所含补锂材料的前驱体，如实施例中，该补锂材料前驱体可以是包括LxMyOz前驱体。那么该补锂材料前驱体经步骤S02中的烧结处理后，其生成如上文的如LxMyOz。
步骤S01中的氟源是提供氟原子，因此，实施例中，该氟源包括氟化铵、氟化钠、氟化钾、氟化锂、氟化铝、氟氢化钾、氟氢化钠中的至少一种。该些氟源能够在步骤S02中的烧结处理过程中，氟原子能够替代在烧结处理过程中生成的补锂材料所含的氧原子。
实施例中，该氟源与补锂材料前驱体的混合比例，应该满足在生成的正极补锂添加剂中，替代氧原子的氟原子是正极补锂添加剂中氧原子摩尔数的0.01-0.1倍。如实施例中，该补锂材料前驱体包括过渡金属盐、锂源等原料形成的混合物时，那么此时补锂材料前驱体中含有氧元素，如补锂材料前驱体为LxMyOz的前驱体时，那么在此时该氟源中的氟元素与过渡金属盐中氧元素的摩尔比为0.01-1:1，进一步为0.01-0.1:1，更进一步为0.02-0.2:1。通过对氟源的混合比例，能够适度的控制氟原子取代氧原子的量，从而提高制备正极补锂添加剂的倍率性能、电压和热稳定性能等性能，并同时还调节控制正极补锂添加剂的粒径，使得其粒径相对较小。
在具体实施例中，包括过渡金属盐、锂源等原料形成的混合物是补锂材料前驱体中，该过渡金属盐可以是LxMyOz中M所示的过渡金属，如可以但不仅 仅包括草酸铵铁、硝酸铁(锰、铜)、硫酸铁(锰、铜)、氯化铁(锰、铜)、三氧化二铁(二氧化锰、氧化亚锰，氧化铜、氧化亚铜)、乙酸铁其中的一种或多种，锂源可以但不仅仅包括LiOH、Li2CO3、CH3COOLi、CH3CH2OLi、LiNO3、LiCl、Li2SO4中的至少一种。
另外，步骤S01中的混合处理可以是固相混合处理还可以是液相混合法。其中，固相混合处理如可以包括固相球磨机混合、豆浆机混合、三维混料机混合、高效混料机混合、融合机混合等中至少一种。液相混合法可以包括搅拌混合、液相混合后喷雾干燥、溶胶凝胶法等。当采用喷雾干燥时，则还可以添加分散剂，分散剂为聚乙烯吡咯烷酮(PVP)、聚乙二醇(PEG)、聚乙烯醇中的一种或多种，该分散剂添加量可以为过渡金属盐以及铁源质量总质量的1-5％，喷雾干燥的进风温度为110-180℃。
步骤S02中，前驱体混合物料在烧结处理过程中，前驱体混合物料中的补锂材料前驱体反应生成补锂材料，如上文的补锂材料。在此过程中，氟源也参与了反应，由于氟原子和氧原子的直径相差较小，而且由于氟原子和氧原子的直径相差较小，在高温作用下，容易发生部分替代，也即氟替代氧原子，这样氟原子替代了补锂材料中的部分氧原子，占据了氧原子的氧空位。
实施例中，该烧结处理的温度为500-1000℃，时间为4-24h。该烧结处理条件如惰性气氛和该温度范围，能够有效使得补锂材料前驱体反应生成补锂材料。同时，生成的正极补锂添加剂是稳定性较好的材料，反应活性并不高，因此，氟源很难也即是几乎不与和正极补锂添加剂直接发生反应生成氟化物，而是使得氟原子替代了补锂材料中的氧原子，且不破坏补锂材料自身的结构。而正极补锂添加剂表面的残碱或者锂金属是反应活性较高的物质，因此，其可以与氟源更容易反应生成氟化物。从而提高补锂材料的电压和热稳定等性能，提升烧结处理生成的正极补锂添加剂电化学性能和其安全性能。
另外，在烧结处理中，由于烧结处理生成的补锂材料表层或表面一般还残留有前驱体原料或其他残碱等杂质，因此，该氟源在烧结过程中还会与生成补 锂材料表层或表面残留的该些前驱体原料或其他残碱等杂质反应，从而生成疏水氟化物，如可以是氟化锂等，从而起到提高正极补锂添加剂的离子导率和隔绝环境等作用。
步骤S02中，惰性气氛保证烧结处理生成目标产物的稳定性，如实施例中，可以是化学惰性气体构成的气氛，实施例中，该化学惰性气体可以是常规的化学惰性气体，如Ar、N2、He等中的至少一种。
在进一步实施例中，在上述烧结处理后，还包括在补锂材料表面形成疏水封装层的步骤。形成疏水封装层的方法可以根据膜层结构和材料选取对应或适合方法形成。如实施例中，当疏水封装层为碳包覆层时，该碳包覆层可以是使用固态碳源进行热裂解包覆。如果采用固态碳源包覆，则首先将上述经裂解处理后的正极补锂添加剂经破碎后的材料与固相碳源混合，混合方法包含球磨机固相混合、豆浆机混合、三维混料机混合、高效混料机混合、融合机混合等至少其中一种。混合后在惰性条件下进行烧结。碳源可以是葡萄糖、蔗糖、淀粉、柠檬酸、纤维素、聚四氟乙烯(PTFE)、聚偏氟乙烯(PVDF)、沥青等其中的至少一种。惰性气氛可以为Ar、N2、He中的至少一种。烧结温度可以为400-800℃，时间为1-10h。该烧结处理能够使得碳包覆层均匀，且致密，如果温度过低，碳源会难以裂解，达不到碳包覆效果，如果温度过高，可能导致碳源裂解太快，造成碳包覆不均匀。最终碳和补锂材料的质量比控制可以为(2-20):100，该混合比例如果最终碳含量太低，碳无法对补锂材料进行完整的包覆，材料表面导电性会存在缺陷位置；如果碳含量太高，碳自身容量较低，会使材料整体的容量下降。
因此，上述正极补锂添加剂的制备方法通过氟源对补锂材料进行原位掺杂，能够有效在补锂材料中掺杂氟原子，并取代补锂材料所含氧原子，从而赋予制备的正极补锂添加剂具有高的倍率性能、电压和热稳定性能，提高了补锂材料的补锂效果和电化学性能以及安全性高。另外，正极补锂添加剂的制备方法能够保证制备的正极补锂添加剂结构和电化学性能稳定，而且效率高，节约生产 成本。
第三方面，本申请实施例还提供了一种电极片。本申请实施例电极片包括电极集流体和结合在电极集流体表面的电极活性层，电极活性层中含有上文本申请实施例电极正极补锂添加剂。由于本申请实施例电极片含有上述本申请实施例电极正极补锂添加剂，因此，在充放电中过程中，电极片所含的正极补锂添加剂发挥上文作用，能够作为锂源在首圈充电过程中作为“牺牲剂”首先被消耗，用以补充负极形成SEI膜而消耗掉的不可逆的锂离子，从而保持电池体系内锂离子的充裕，提高电池首效和整体电化学性能。而且电极片质量稳定且良品率高。
在一实施例中，电极活性层中所含上文本申请实施例电极正极补锂添加剂的质量含量可以为1-20wt％；优选地，2-10wt％。电极活性层包括除了该电极正极补锂添加剂之外，还包括电极活性材料、粘结剂和导电剂，其中，粘结剂可以是常用的电极粘结剂，如包括聚偏氯乙烯、可溶性聚四氟乙烯、丁苯橡胶、羟丙基甲基纤维素、甲基纤维素、羧甲基纤维素、聚乙烯醇、丙烯腈共聚物、海藻酸钠、壳聚糖和壳聚糖衍生物中的一种或多种。本申请实施方式中，导电剂可以是常用的导电剂，如包括石墨、碳黑、乙炔黑、石墨烯、碳纤维、C60和碳纳米管中的一种或多种。电极活性材料可以是正极活性材料或负极活性材料，具体实施例中，正极活性材料包括钴酸锂、锰酸锂、磷酸铁锂、磷酸锰铁锂、磷酸钒锂，磷酸钒氧锂、氟代磷酸钒锂、钛酸锂、镍钴锰酸锂、镍钴铝酸锂中的一种或多种。
实施例中，电极片制备过程可以为：将电极活性材料、电极正极补锂添加剂、导电剂与粘结剂混合得到电极浆料，将电极浆料涂布在电极集流体上，经干燥、辊压、模切等步骤制备得到电极片。
第四方面，本申请实施例还提供了一种二次电池。本申请实施例二次电池包括正极片、负极片、隔膜和电解质等必要的部件，当然还包括其他必要或辅助的部件。其中，正极片或/和负极片为上述本申请实施例电极片，具体地，当 上述电极片为正极片，且含有上文本申请实施例正极补锂添加剂，并且该正极补锂添加剂为正极补锂添加剂，那么二次电池所含的正极片为上述本申请实施例电极片(正极片)。
由于本申请实施例二次电池中含有上文本申请实施例正极补锂添加剂，基于上文本申请实施例正极补锂添加剂所具有优异补锂性能或进一步具有离子传导性和/或电子传导性、加工性能，赋予本申请实施例二次电池优异的首次库伦效率和电池容量以及循环性能，寿命长，电化学性能稳定。
以下通过多个具体实施例来举例说明本申请实施例正极补锂添加剂及其制备方法和应用等。
1.正极补锂添加剂及其粒径控制方法实施例：
实施例1
本实施例提供一种掺氟正极补锂添加剂及制备方法。该正极补锂添加剂包括Li2NiO2补锂材料和包覆该补锂材料的碳包覆层。其中，补锂材料中掺杂有氟原子。
本实施例正极补锂添加剂的控制方法包括如下步骤：
S1.将Li2NiO2补锂材料前驱体与氟化铵按照摩尔比1:0.2(氧氟摩尔比为1:0.1)的比例进行固相混合处理，得到前驱体混合物料；
S2.将前驱体混合物料在氩气的保护环境于580℃下烧结处理12小时，得到掺氟补锂材料；
S3.在掺氟补锂材料表面原位形成碳包覆层：将掺氟补锂材料与其质量5％的中温沥青粉末通过固相混合，再在氩气环境于600℃下烧结6h，得到碳包覆掺氟补锂材料。
经检测，本实施例补锂材料中掺杂有氟原子，该氟原子是取代补锂材料中的氧原子，形成的化合物为Li2NiO1.96F0.08，通过激光粒度分析仪测得正极补锂添加剂的粒径D50为5.32μm。
实施例2
本实施例提供一种掺氟正极补锂添加剂及制备方法。该正极补锂添加剂包括Li5FeO4补锂材料和包覆该补锂材料的碳包覆层。其中，补锂材料中掺杂有氟原子。
本实施例正极补锂添加剂的控制方法包括如下步骤：
S1.将Li5FeO4补锂材料前驱体与氟氢化钠按照摩尔比1:0.3(氧氟摩尔比为1：0.15)的比例进行固相混合处理，得到前驱体混合物料；
S2.将前驱体混合物料在氩气的保护环境于650℃下烧结处理8小时，得到掺氟补锂材料；
S3.在掺氟补锂材料表面原位形成碳包覆层：将掺氟补锂材料与其质量7％的葡萄糖粉末通过固相混合，再在氩气环境于650℃下烧结4h，得到碳包覆掺氟补锂材料。
经检测，本实施例补锂材料中掺杂有氟原子，该氟原子是取代补锂材料中的氧原子，形成的化合物为Li5FeO3.93F0.14，通过激光粒度分析仪测得正极补锂添加剂的粒径D50为3.64μm。
对比例1
本对比例提供一种正极补锂添加剂及其制备方法。本对比例正极补锂添加剂为实施例1中步骤S1中制备的补锂材料为核体和实施例1中步骤S3中制备的碳包覆层。也即是与实施例1相比，本对比例正极补锂添加剂不含掺杂氟原子。
对比例2
本对比例提供一种正极补锂添加剂及其制备方法。本对比例正极补锂添加剂为实施例2中步骤S1中制备的补锂材料为核体和实施例2中步骤S3中制备的碳包覆层。也即是与实施例1相比，本对比例正极补锂添加剂不含掺杂氟原子。
2.锂离子电池实施例：
将上述实施例1至实施例2提供的正极补锂添加剂和对比例提供的正极补 锂添加剂分别按照如下方法组装成正极电极和锂离子电池：
正电极：在相同的条件下，按照(主材+补锂材料)：Super P-Li：PVDF，四者质量比为95:2:3的比例混合，其中主材为纳米磷酸铁锂材料，补锂材料为主材质量的3％，以N-甲基吡咯烷酮(NMP)作为溶剂将材料混合均匀制成浆料，再均匀涂覆在铝箔表面，辊压到一定厚度后，110℃下真空干燥12h，制成正极极片；其中，正极补锂添加剂分别为上述实施例1至实施例2提供的正极补锂添加剂和对比例提供的正极补锂添加剂；
对电极：锂金属片；
电解液：电解液为1mol/L的LiPF6/碳酸乙烯酯:碳酸甲乙酯(体积比)＝1:1溶液；
隔膜：聚丙烯微孔膜；
电池外壳：(包括负极壳、不锈钢垫片和正极壳)型号为CR2032型；
锂离子电池组装：负极壳-不锈钢垫片-锂金属片-隔膜-电解液-正极片-正极壳的组装顺序在惰性气氛手套箱内组装成半电池。
3.锂离子电池相关性能测试
将上述锂离子电池实施例中组装的各锂离子电池相关电化学性能进行测试，测试条件为：
测试条件：将装配好的电池在25℃恒温室内上架，搁置6h后进行充放电测试。首先以0.05C恒流充至4.3V，再恒压充至截止电流为0.01C停止，再以0.05C放电至2V，第二圈开始充放电电压窗口调整为2-3.75V，以0.05C充放电，恒压充电截止电流为0.01C，以该充放电条件循环至100圈。记录电池首次充放电容量，以及第100圈充放电容量。
首次库伦效率为首次放电容量和首次充电容量的比值，100圈容量保持率为第100圈放电容量和首次放电容量的比值。
锂离子电池相关电化学性能如下表1所示：
表1
从表格中实施例和对比例的数据结果可以看出：当补锂材料经过氟掺杂以及碳包覆之后，具体如实施例1和实施例2中的正极补锂添加剂。由于表面反应以及碳沉积，在均含有碳包覆层的前提下，含氟掺杂核体的正极补锂添加剂的粒径略大于非氟掺杂核体的正极补锂添加剂的粒径，具体如实施例1的材料粒径D50要大于对比例例1，实施例2的材料粒径D50要大于对比例例2。通过实施例和对比例的扣电测试数据对比结果可以看出：实施例1和实施例2首次充电容量和放电容量都相对对比例1和对比例2明显提高，首效相对对比例1和对比例2明显也得以明显提高，这是由于氟掺杂和碳包覆之后补锂材料的结构更加稳定，加工环境中水分的影响也变得更弱，也即材料变质更少，从而能发挥更高的充电容量。另外，由于补锂材料首次脱锂之后，几乎不再嵌锂，也即不再参与电池中的电化学反应，经过氟掺杂的材料，脱锂之后材料的结构稳定，且由于碳包覆之后材料具有良好导电性，从而脱锂之后还可以作为导电剂在电池内发挥导电剂作用。因此，理想的是，将本申请实施例正极补锂添加剂设计为核壳结构，将氟原子替代氧空位的补锂材料作为核体，以提高本申请实施例正极补锂添加剂的高压和热稳定性以及补锂效果等特性，从而提高相应电池的循环性能和安全性能。
以上数据可以很好证明添加少量本申请实施例正极补锂添加剂，就可以使电池容量和首效以及循环性能得以明显改善，能有效提升电池能量密度，具有良好的发展前景。
以上实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对本申请专利范围的限制。应当指出的是，对于本领域的 普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请专利的保护范围应以所附权利要求为准。

Claims (15)

  1. 一种正极补锂添加剂，包括补锂材料，其特征在于：在所述补锂材料中还含有氟原子，且所述氟原子替代所述补锂材料中的氧原子并处于氧空位。
  2. 根据权利要求1所述的正极补锂添加剂，其特征在于：替代所述氧原子的所述氟原子是所述正极补锂添加剂中的氧原子摩尔数的0.01-0.8倍。
  3. 根据权利要求1或2所述的正极补锂添加剂，其特征在于：替代所述氧原子的所述氟原子是所述正极补锂添加剂中的氧原子摩尔数的0.01-0.1倍。
  4. 根据权利要求1-3任一项所述的正极补锂添加剂，其特征在于：所述正极补锂添加剂的表层中或表面还含有疏水氟化物。
  5. 根据权利要求4所述的正极补锂添加剂，其特征在于：所述疏水氟化物包括氟化锂。
  6. 根据权利要求4或5所述的正极补锂添加剂，其特征在于：所述疏水氟化物在所述正极补锂添加剂的质量含量为0.1％-2％。
  7. 根据权利要求1-6任一项所述的正极补锂添加剂，其特征在于：所述正极补锂添加剂的粒径为1-20μm。
  8. 根据权利要求1-7任一项所述的正极补锂添加剂，其特征在于：所述正极补锂添加剂还包括疏水封装层，所述疏水封装层包覆所述补锂材料；和/或
    所述补锂材料包括LxMyOz，其中，分子式中的L为Li或/和Li与不超过30％的K、Na中至少一种的混合碱金属元素；M包括Fe、Co、Ni、Mn、V、Fe-Co、Cu、Mo、Al、Ti、Mg其中的至少一种；0＜x≤6，0＜y≤3，0＜z≤5。
  9. 根据权利要求8所述的正极补锂添加剂，其特征在于：所述LxMyOz包括Li5Fe0.98Al0.02O4、Li2NiO2、Li5FeO4、Li2MnO2、Li6MnO4、Li2CuO2中的至少一种。
  10. 根据权利要求8或9所述的正极补锂添加剂，其特征在于：所述疏水封装层包括离子导体封装层、电子导体封装层中的至少一层；和/或
    所述疏水封装层的厚度为5-100nm。
  11. 根据权利要求10所述的正极补锂添加剂，其特征在于：所述离子导体封装层的材料包括钙钛矿型、NASICON型、石榴石型中的至少一种；
    所述电子导体封装层的材料包括碳材料、导电氧化物、导电有机物中的至少一种。
  12. 一种正极补锂添加剂的制备方法，其特征在于，包括如下步骤：
    将补锂材料前驱体与氟源进行混合处理，得到前驱体混合物料；
    将所述前驱体混合物料于惰性气氛中烧结处理，得到正极补锂添加剂。
  13. 根据权利要求12所述的制备方法，其特征在于：所述补锂材料前驱体包括LxMyOz前驱体，其中，分子式中的L为Li或/和Li与不超过30％的K、Na中至少一种的混合碱金属元素；M包括Fe、Co、Ni、Mn、V、Fe-Co、Cu、Mo、Al、Ti、Mg其中的至少一种；0＜x≤6，0＜y≤3，0＜z≤5；和/或
    所述补锂材料前驱体包括过渡金属盐，且所述氟源中的氟元素与所述过渡金属盐中氧元素的摩尔比为0.01-1:1；和/或
    所述烧结处理的温度为500-1000℃，时间为4-24h；和/或
    所述氟源包括氟化铵、氟化钠、氟化钾、氟化锂、氟化铝、氟氢化钾、氟氢化钠中的至少一种；和/或
    在所述烧结处理后，还包括在经烧结处理后的材料表面形成包覆所述材料的疏水封装层。
  14. 一种电极片，包括集流体和结合在集流体表面的电极活性层，其特征在于：所述电极活性层中含有权利要求1-11任一项所述的正极补锂添加剂或由权利要求12-13任一项所述的制备方法制备的正极补锂添加剂。
  15. 一种二次电池，包括正极片和负极片，其特征在于：所述正极片和/或负极片为权利要求14所述的电极片。
PCT/CN2023/072605 2022-02-25 2023-01-17 正极补锂添加剂及其制备方法和应用 WO2023160307A1 (zh)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117865226A (zh) * 2024-03-13 2024-04-12 天能帅福得能源股份有限公司 一种正极补锂添加剂及其制备方法和锂离子电池

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115312885A (zh) * 2022-02-25 2022-11-08 深圳市德方创域新能源科技有限公司 正极补锂添加剂及其制备方法和应用
CN115911606A (zh) * 2022-11-09 2023-04-04 深圳市德方创域新能源科技有限公司 补锂材料及其制备方法和应用

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107845836A (zh) * 2017-09-22 2018-03-27 深圳市比克动力电池有限公司 一种锂离子电池正极补锂添加剂及其制备方法和应用
CN109301242A (zh) * 2018-09-19 2019-02-01 河南工学院 一种锂离子电池正极补锂材料Li5FeO4的制备方法及应用
JP2019085315A (ja) * 2017-11-09 2019-06-06 株式会社豊田自動織機 炭素被覆Ｌｉ５ＦｅＯ４
CN109950484A (zh) * 2019-03-06 2019-06-28 蜂巢能源科技有限公司 制备富锂复合正极材料的方法、正极、电池
CN112164796A (zh) * 2020-09-16 2021-01-01 合肥国轩高科动力能源有限公司 一种锂离子电池正极材料的预锂化添加剂及其制备方法和应用
CN113793983A (zh) * 2021-08-09 2021-12-14 恒大新能源技术(深圳)有限公司 补锂添加剂及其制备方法与应用
CN115312885A (zh) * 2022-02-25 2022-11-08 深圳市德方创域新能源科技有限公司 正极补锂添加剂及其制备方法和应用

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107845836A (zh) * 2017-09-22 2018-03-27 深圳市比克动力电池有限公司 一种锂离子电池正极补锂添加剂及其制备方法和应用
JP2019085315A (ja) * 2017-11-09 2019-06-06 株式会社豊田自動織機 炭素被覆Ｌｉ５ＦｅＯ４
CN109301242A (zh) * 2018-09-19 2019-02-01 河南工学院 一种锂离子电池正极补锂材料Li5FeO4的制备方法及应用
CN109950484A (zh) * 2019-03-06 2019-06-28 蜂巢能源科技有限公司 制备富锂复合正极材料的方法、正极、电池
CN112164796A (zh) * 2020-09-16 2021-01-01 合肥国轩高科动力能源有限公司 一种锂离子电池正极材料的预锂化添加剂及其制备方法和应用
CN113793983A (zh) * 2021-08-09 2021-12-14 恒大新能源技术(深圳)有限公司 补锂添加剂及其制备方法与应用
CN115312885A (zh) * 2022-02-25 2022-11-08 深圳市德方创域新能源科技有限公司 正极补锂添加剂及其制备方法和应用

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117865226A (zh) * 2024-03-13 2024-04-12 天能帅福得能源股份有限公司 一种正极补锂添加剂及其制备方法和锂离子电池

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